--- /dev/null
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+ * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--- /dev/null
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go. This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation. If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.
--- /dev/null
+package analysis
+
+import (
+ "flag"
+ "fmt"
+ "go/ast"
+ "go/token"
+ "go/types"
+ "reflect"
+)
+
+// An Analyzer describes an analysis function and its options.
+type Analyzer struct {
+ // The Name of the analyzer must be a valid Go identifier
+ // as it may appear in command-line flags, URLs, and so on.
+ Name string
+
+ // Doc is the documentation for the analyzer.
+ // The part before the first "\n\n" is the title
+ // (no capital or period, max ~60 letters).
+ Doc string
+
+ // Flags defines any flags accepted by the analyzer.
+ // The manner in which these flags are exposed to the user
+ // depends on the driver which runs the analyzer.
+ Flags flag.FlagSet
+
+ // Run applies the analyzer to a package.
+ // It returns an error if the analyzer failed.
+ //
+ // On success, the Run function may return a result
+ // computed by the Analyzer; its type must match ResultType.
+ // The driver makes this result available as an input to
+ // another Analyzer that depends directly on this one (see
+ // Requires) when it analyzes the same package.
+ //
+ // To pass analysis results between packages (and thus
+ // potentially between address spaces), use Facts, which are
+ // serializable.
+ Run func(*Pass) (interface{}, error)
+
+ // RunDespiteErrors allows the driver to invoke
+ // the Run method of this analyzer even on a
+ // package that contains parse or type errors.
+ RunDespiteErrors bool
+
+ // Requires is a set of analyzers that must run successfully
+ // before this one on a given package. This analyzer may inspect
+ // the outputs produced by each analyzer in Requires.
+ // The graph over analyzers implied by Requires edges must be acyclic.
+ //
+ // Requires establishes a "horizontal" dependency between
+ // analysis passes (different analyzers, same package).
+ Requires []*Analyzer
+
+ // ResultType is the type of the optional result of the Run function.
+ ResultType reflect.Type
+
+ // FactTypes indicates that this analyzer imports and exports
+ // Facts of the specified concrete types.
+ // An analyzer that uses facts may assume that its import
+ // dependencies have been similarly analyzed before it runs.
+ // Facts must be pointers.
+ //
+ // FactTypes establishes a "vertical" dependency between
+ // analysis passes (same analyzer, different packages).
+ FactTypes []Fact
+}
+
+func (a *Analyzer) String() string { return a.Name }
+
+// A Pass provides information to the Run function that
+// applies a specific analyzer to a single Go package.
+//
+// It forms the interface between the analysis logic and the driver
+// program, and has both input and an output components.
+//
+// As in a compiler, one pass may depend on the result computed by another.
+//
+// The Run function should not call any of the Pass functions concurrently.
+type Pass struct {
+ Analyzer *Analyzer // the identity of the current analyzer
+
+ // syntax and type information
+ Fset *token.FileSet // file position information
+ Files []*ast.File // the abstract syntax tree of each file
+ OtherFiles []string // names of non-Go files of this package
+ Pkg *types.Package // type information about the package
+ TypesInfo *types.Info // type information about the syntax trees
+
+ // Report reports a Diagnostic, a finding about a specific location
+ // in the analyzed source code such as a potential mistake.
+ // It may be called by the Run function.
+ Report func(Diagnostic)
+
+ // ResultOf provides the inputs to this analysis pass, which are
+ // the corresponding results of its prerequisite analyzers.
+ // The map keys are the elements of Analysis.Required,
+ // and the type of each corresponding value is the required
+ // analysis's ResultType.
+ ResultOf map[*Analyzer]interface{}
+
+ // -- facts --
+
+ // ImportObjectFact retrieves a fact associated with obj.
+ // Given a value ptr of type *T, where *T satisfies Fact,
+ // ImportObjectFact copies the value to *ptr.
+ //
+ // ImportObjectFact panics if called after the pass is complete.
+ // ImportObjectFact is not concurrency-safe.
+ ImportObjectFact func(obj types.Object, fact Fact) bool
+
+ // ImportPackageFact retrieves a fact associated with package pkg,
+ // which must be this package or one of its dependencies.
+ // See comments for ImportObjectFact.
+ ImportPackageFact func(pkg *types.Package, fact Fact) bool
+
+ // ExportObjectFact associates a fact of type *T with the obj,
+ // replacing any previous fact of that type.
+ //
+ // ExportObjectFact panics if it is called after the pass is
+ // complete, or if obj does not belong to the package being analyzed.
+ // ExportObjectFact is not concurrency-safe.
+ ExportObjectFact func(obj types.Object, fact Fact)
+
+ // ExportPackageFact associates a fact with the current package.
+ // See comments for ExportObjectFact.
+ ExportPackageFact func(fact Fact)
+
+ /* Further fields may be added in future. */
+ // For example, suggested or applied refactorings.
+}
+
+// Reportf is a helper function that reports a Diagnostic using the
+// specified position and formatted error message.
+func (pass *Pass) Reportf(pos token.Pos, format string, args ...interface{}) {
+ msg := fmt.Sprintf(format, args...)
+ pass.Report(Diagnostic{Pos: pos, Message: msg})
+}
+
+func (pass *Pass) String() string {
+ return fmt.Sprintf("%s@%s", pass.Analyzer.Name, pass.Pkg.Path())
+}
+
+// A Fact is an intermediate fact produced during analysis.
+//
+// Each fact is associated with a named declaration (a types.Object) or
+// with a package as a whole. A single object or package may have
+// multiple associated facts, but only one of any particular fact type.
+//
+// A Fact represents a predicate such as "never returns", but does not
+// represent the subject of the predicate such as "function F" or "package P".
+//
+// Facts may be produced in one analysis pass and consumed by another
+// analysis pass even if these are in different address spaces.
+// If package P imports Q, all facts about Q produced during
+// analysis of that package will be available during later analysis of P.
+// Facts are analogous to type export data in a build system:
+// just as export data enables separate compilation of several passes,
+// facts enable "separate analysis".
+//
+// Each pass (a, p) starts with the set of facts produced by the
+// same analyzer a applied to the packages directly imported by p.
+// The analysis may add facts to the set, and they may be exported in turn.
+// An analysis's Run function may retrieve facts by calling
+// Pass.Import{Object,Package}Fact and update them using
+// Pass.Export{Object,Package}Fact.
+//
+// A fact is logically private to its Analysis. To pass values
+// between different analyzers, use the results mechanism;
+// see Analyzer.Requires, Analyzer.ResultType, and Pass.ResultOf.
+//
+// A Fact type must be a pointer.
+// Facts are encoded and decoded using encoding/gob.
+// A Fact may implement the GobEncoder/GobDecoder interfaces
+// to customize its encoding. Fact encoding should not fail.
+//
+// A Fact should not be modified once exported.
+type Fact interface {
+ AFact() // dummy method to avoid type errors
+}
+
+// A Diagnostic is a message associated with a source location.
+//
+// An Analyzer may return a variety of diagnostics; the optional Category,
+// which should be a constant, may be used to classify them.
+// It is primarily intended to make it easy to look up documentation.
+type Diagnostic struct {
+ Pos token.Pos
+ Category string // optional
+ Message string
+}
--- /dev/null
+// The vet-lite command is a driver for static checkers conforming to
+// the golang.org/x/tools/go/analysis API. It must be run by go vet:
+//
+// $ GOVETTOOL=$(which vet-lite) go vet
+//
+// For a checker also capable of running standalone, use multichecker.
+package main
+
+import (
+ "flag"
+ "log"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/internal/analysisflags"
+ "golang.org/x/tools/go/analysis/internal/unitchecker"
+
+ "golang.org/x/tools/go/analysis/passes/asmdecl"
+ "golang.org/x/tools/go/analysis/passes/assign"
+ "golang.org/x/tools/go/analysis/passes/atomic"
+ "golang.org/x/tools/go/analysis/passes/bools"
+ "golang.org/x/tools/go/analysis/passes/buildtag"
+ "golang.org/x/tools/go/analysis/passes/cgocall"
+ "golang.org/x/tools/go/analysis/passes/composite"
+ "golang.org/x/tools/go/analysis/passes/copylock"
+ "golang.org/x/tools/go/analysis/passes/httpresponse"
+ "golang.org/x/tools/go/analysis/passes/loopclosure"
+ "golang.org/x/tools/go/analysis/passes/lostcancel"
+ "golang.org/x/tools/go/analysis/passes/nilfunc"
+ "golang.org/x/tools/go/analysis/passes/pkgfact"
+ "golang.org/x/tools/go/analysis/passes/printf"
+ "golang.org/x/tools/go/analysis/passes/shift"
+ "golang.org/x/tools/go/analysis/passes/stdmethods"
+ "golang.org/x/tools/go/analysis/passes/structtag"
+ "golang.org/x/tools/go/analysis/passes/tests"
+ "golang.org/x/tools/go/analysis/passes/unreachable"
+ "golang.org/x/tools/go/analysis/passes/unsafeptr"
+ "golang.org/x/tools/go/analysis/passes/unusedresult"
+)
+
+var analyzers = []*analysis.Analyzer{
+ // For now, just the traditional vet suite:
+ asmdecl.Analyzer,
+ assign.Analyzer,
+ atomic.Analyzer,
+ bools.Analyzer,
+ buildtag.Analyzer,
+ cgocall.Analyzer,
+ composite.Analyzer,
+ copylock.Analyzer,
+ httpresponse.Analyzer,
+ loopclosure.Analyzer,
+ lostcancel.Analyzer,
+ nilfunc.Analyzer,
+ pkgfact.Analyzer,
+ printf.Analyzer,
+ // shadow.Analyzer, // experimental; not enabled by default
+ shift.Analyzer,
+ stdmethods.Analyzer,
+ structtag.Analyzer,
+ tests.Analyzer,
+ unreachable.Analyzer,
+ unsafeptr.Analyzer,
+ unusedresult.Analyzer,
+}
+
+func main() {
+ log.SetFlags(0)
+ log.SetPrefix("vet: ")
+
+ if err := analysis.Validate(analyzers); err != nil {
+ log.Fatal(err)
+ }
+
+ analyzers = analysisflags.Parse(analyzers, true)
+
+ args := flag.Args()
+ if len(args) != 1 || !strings.HasSuffix(args[0], ".cfg") {
+ log.Fatalf("invalid command: want .cfg file (this reduced version of vet is intended to be run only by the 'go vet' command)")
+ }
+
+ unitchecker.Main(args[0], analyzers)
+}
--- /dev/null
+/*
+
+The analysis package defines the interface between a modular static
+analysis and an analysis driver program.
+
+
+THIS INTERFACE IS EXPERIMENTAL AND SUBJECT TO CHANGE.
+We aim to finalize it by November 2018.
+
+Background
+
+A static analysis is a function that inspects a package of Go code and
+reports a set of diagnostics (typically mistakes in the code), and
+perhaps produces other results as well, such as suggested refactorings
+or other facts. An analysis that reports mistakes is informally called a
+"checker". For example, the printf checker reports mistakes in
+fmt.Printf format strings.
+
+A "modular" analysis is one that inspects one package at a time but can
+save information from a lower-level package and use it when inspecting a
+higher-level package, analogous to separate compilation in a toolchain.
+The printf checker is modular: when it discovers that a function such as
+log.Fatalf delegates to fmt.Printf, it records this fact, and checks
+calls to that function too, including calls made from another package.
+
+By implementing a common interface, checkers from a variety of sources
+can be easily selected, incorporated, and reused in a wide range of
+driver programs including command-line tools (such as vet), text editors and
+IDEs, build and test systems (such as go build, Bazel, or Buck), test
+frameworks, code review tools, code-base indexers (such as SourceGraph),
+documentation viewers (such as godoc), batch pipelines for large code
+bases, and so on.
+
+
+Analyzer
+
+The primary type in the API is Analyzer. An Analyzer statically
+describes an analysis function: its name, documentation, flags,
+relationship to other analyzers, and of course, its logic.
+
+To define an analysis, a user declares a (logically constant) variable
+of type Analyzer. Here is a typical example from one of the analyzers in
+the go/analysis/passes/ subdirectory:
+
+ package unusedresult
+
+ var Analyzer = &analysis.Analyzer{
+ Name: "unusedresult",
+ Doc: "check for unused results of calls to some functions",
+ Run: run,
+ ...
+ }
+
+ func run(pass *analysis.Pass) (interface{}, error) {
+ ...
+ }
+
+
+An analysis driver is a program such as vet that runs a set of
+analyses and prints the diagnostics that they report.
+The driver program must import the list of Analyzers it needs.
+Typically each Analyzer resides in a separate package.
+To add a new Analyzer to an existing driver, add another item to the list:
+
+ import ( "unusedresult"; "nilness"; "printf" )
+
+ var analyses = []*analysis.Analyzer{
+ unusedresult.Analyzer,
+ nilness.Analyzer,
+ printf.Analyzer,
+ }
+
+A driver may use the name, flags, and documentation to provide on-line
+help that describes the analyses its performs.
+The vet command, shown below, is an example of a driver that runs
+multiple analyzers. It is based on the multichecker package
+(see the "Standalone commands" section for details).
+
+ $ go build golang.org/x/tools/cmd/vet
+ $ ./vet help
+ vet is a tool for static analysis of Go programs.
+
+ Usage: vet [-flag] [package]
+
+ Registered analyzers:
+
+ asmdecl report mismatches between assembly files and Go declarations
+ assign check for useless assignments
+ atomic check for common mistakes using the sync/atomic package
+ ...
+ unusedresult check for unused results of calls to some functions
+
+ $ ./vet help unusedresult
+ unusedresult: check for unused results of calls to some functions
+
+ Analyzer flags:
+
+ -unusedresult.funcs value
+ comma-separated list of functions whose results must be used (default Error,String)
+ -unusedresult.stringmethods value
+ comma-separated list of names of methods of type func() string whose results must be used
+
+ Some functions like fmt.Errorf return a result and have no side effects,
+ so it is always a mistake to discard the result. This analyzer reports
+ calls to certain functions in which the result of the call is ignored.
+
+ The set of functions may be controlled using flags.
+
+The Analyzer type has more fields besides those shown above:
+
+ type Analyzer struct {
+ Name string
+ Doc string
+ Flags flag.FlagSet
+ Run func(*Pass) (interface{}, error)
+ RunDespiteErrors bool
+ ResultType reflect.Type
+ Requires []*Analyzer
+ FactTypes []Fact
+ }
+
+The Flags field declares a set of named (global) flag variables that
+control analysis behavior. Unlike vet, analysis flags are not declared
+directly in the command line FlagSet; it is up to the driver to set the
+flag variables. A driver for a single analysis, a, might expose its flag
+f directly on the command line as -f, whereas a driver for multiple
+analyses might prefix the flag name by the analysis name (-a.f) to avoid
+ambiguity. An IDE might expose the flags through a graphical interface,
+and a batch pipeline might configure them from a config file.
+See the "findcall" analyzer for an example of flags in action.
+
+The RunDespiteErrors flag indicates whether the analysis is equipped to
+handle ill-typed code. If not, the driver will skip the analysis if
+there were parse or type errors.
+The optional ResultType field specifies the type of the result value
+computed by this analysis and made available to other analyses.
+The Requires field specifies a list of analyses upon which
+this one depends and whose results it may access, and it constrains the
+order in which a driver may run analyses.
+The FactTypes field is discussed in the section on Modularity.
+The analysis package provides a Validate function to perform basic
+sanity checks on an Analyzer, such as that its Requires graph is
+acyclic, its fact and result types are unique, and so on.
+
+Finally, the Run field contains a function to be called by the driver to
+execute the analysis on a single package. The driver passes it an
+instance of the Pass type.
+
+
+Pass
+
+A Pass describes a single unit of work: the application of a particular
+Analyzer to a particular package of Go code.
+The Pass provides information to the Analyzer's Run function about the
+package being analyzed, and provides operations to the Run function for
+reporting diagnostics and other information back to the driver.
+
+ type Pass struct {
+ Fset *token.FileSet
+ Files []*ast.File
+ OtherFiles []string
+ Pkg *types.Package
+ TypesInfo *types.Info
+ ResultOf map[*Analyzer]interface{}
+ Report func(Diagnostic)
+ ...
+ }
+
+The Fset, Files, Pkg, and TypesInfo fields provide the syntax trees,
+type information, and source positions for a single package of Go code.
+
+The OtherFiles field provides the names, but not the contents, of non-Go
+files such as assembly that are part of this package. See the "asmdecl"
+or "buildtags" analyzers for examples of loading non-Go files and report
+diagnostics against them.
+
+The ResultOf field provides the results computed by the analyzers
+required by this one, as expressed in its Analyzer.Requires field. The
+driver runs the required analyzers first and makes their results
+available in this map. Each Analyzer must return a value of the type
+described in its Analyzer.ResultType field.
+For example, the "ctrlflow" analyzer returns a *ctrlflow.CFGs, which
+provides a control-flow graph for each function in the package (see
+golang.org/x/tools/go/cfg); the "inspect" analyzer returns a value that
+enables other Analyzers to traverse the syntax trees of the package more
+efficiently; and the "buildssa" analyzer constructs an SSA-form
+intermediate representation.
+Each of these Analyzers extends the capabilities of later Analyzers
+without adding a dependency to the core API, so an analysis tool pays
+only for the extensions it needs.
+
+The Report function emits a diagnostic, a message associated with a
+source position. For most analyses, diagnostics are their primary
+result.
+For convenience, Pass provides a helper method, Reportf, to report a new
+diagnostic by formatting a string.
+Diagnostic is defined as:
+
+ type Diagnostic struct {
+ Pos token.Pos
+ Category string // optional
+ Message string
+ }
+
+The optional Category field is a short identifier that classifies the
+kind of message when an analysis produces several kinds of diagnostic.
+
+Most Analyzers inspect typed Go syntax trees, but a few, such as asmdecl
+and buildtag, inspect the raw text of Go source files or even non-Go
+files such as assembly. To report a diagnostic against a line of a
+raw text file, use the following sequence:
+
+ content, err := ioutil.ReadFile(filename)
+ if err != nil { ... }
+ tf := fset.AddFile(filename, -1, len(content))
+ tf.SetLinesForContent(content)
+ ...
+ pass.Reportf(tf.LineStart(line), "oops")
+
+
+Modular analysis with Facts
+
+To improve efficiency and scalability, large programs are routinely
+built using separate compilation: units of the program are compiled
+separately, and recompiled only when one of their dependencies changes;
+independent modules may be compiled in parallel. The same technique may
+be applied to static analyses, for the same benefits. Such analyses are
+described as "modular".
+
+A compiler’s type checker is an example of a modular static analysis.
+Many other checkers we would like to apply to Go programs can be
+understood as alternative or non-standard type systems. For example,
+vet's printf checker infers whether a function has the "printf wrapper"
+type, and it applies stricter checks to calls of such functions. In
+addition, it records which functions are printf wrappers for use by
+later analysis units to identify other printf wrappers by induction.
+A result such as “f is a printf wrapper” that is not interesting by
+itself but serves as a stepping stone to an interesting result (such as
+a diagnostic) is called a "fact".
+
+The analysis API allows an analysis to define new types of facts, to
+associate facts of these types with objects (named entities) declared
+within the current package, or with the package as a whole, and to query
+for an existing fact of a given type associated with an object or
+package.
+
+An Analyzer that uses facts must declare their types:
+
+ var Analyzer = &analysis.Analyzer{
+ Name: "printf",
+ FactTypes: []reflect.Type{reflect.TypeOf(new(isWrapper))},
+ ...
+ }
+
+ type isWrapper struct{} // => *types.Func f “is a printf wrapper”
+
+A driver program ensures that facts for a pass’s dependencies are
+generated before analyzing the pass and are responsible for propagating
+facts between from one pass to another, possibly across address spaces.
+Consequently, Facts must be serializable. The API requires that drivers
+use the gob encoding, an efficient, robust, self-describing binary
+protocol. A fact type may implement the GobEncoder/GobDecoder interfaces
+if the default encoding is unsuitable. Facts should be stateless.
+
+The Pass type has functions to import and export facts,
+associated either with an object or with a package:
+
+ type Pass struct {
+ ...
+ ExportObjectFact func(types.Object, Fact)
+ ImportObjectFact func(types.Object, Fact) bool
+
+ ExportPackageFact func(fact Fact)
+ ImportPackageFact func(*types.Package, Fact) bool
+ }
+
+An Analyzer may only export facts associated with the current package or
+its objects, though it may import facts from any package or object that
+is an import dependency of the current package.
+
+Conceptually, ExportObjectFact(obj, fact) inserts fact into a hidden map keyed by
+the pair (obj, TypeOf(fact)), and the ImportObjectFact function
+retrieves the entry from this map and copies its value into the variable
+pointed to by fact. This scheme assumes that the concrete type of fact
+is a pointer; this assumption is checked by the Validate function.
+See the "printf" analyzer for an example of object facts in action.
+
+
+Testing an Analyzer
+
+The analysistest subpackage provides utilities for testing an Analyzer.
+In a few lines of code, it is possible to run an analyzer on a package
+of testdata files and check that it reported all the expected
+diagnostics and facts (and no more). Expectations are expressed using
+"// want ..." comments in the input code.
+
+
+Standalone commands
+
+Analyzers are provided in the form of packages that a driver program is
+expected to import. The vet command imports a set of several analyses,
+but users may wish to define their own analysis commands that perform
+additional checks. To simplify the task of creating an analysis command,
+either for a single analyzer or for a whole suite, we provide the
+singlechecker and multichecker subpackages.
+
+The singlechecker package provides the main function for a command that
+runs one analysis. By convention, each analyzer such as
+go/passes/findcall should be accompanied by a singlechecker-based
+command such as go/analysis/passes/findcall/cmd/findcall, defined in its
+entirety as:
+
+ package main
+
+ import (
+ "golang.org/x/tools/go/analysis/passes/findcall"
+ "golang.org/x/tools/go/analysis/singlechecker"
+ )
+
+ func main() { singlechecker.Main(findcall.Analyzer) }
+
+A tool that provides multiple analyzers can use multichecker in a
+similar way, giving it the list of Analyzers.
+
+
+
+*/
+package analysis
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package analysisflags defines helpers for processing flags of
+// analysis driver tools.
+package analysisflags
+
+import (
+ "crypto/sha256"
+ "encoding/json"
+ "flag"
+ "fmt"
+ "io"
+ "log"
+ "os"
+ "strconv"
+
+ "golang.org/x/tools/go/analysis"
+)
+
+// Parse creates a flag for each of the analyzer's flags,
+// including (in multi mode) an --analysis.enable flag,
+// parses the flags, then filters and returns the list of
+// analyzers enabled by flags.
+func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
+ // Connect each analysis flag to the command line as -analysis.flag.
+ type analysisFlag struct {
+ Name string
+ Bool bool
+ Usage string
+ }
+ var analysisFlags []analysisFlag
+
+ enabled := make(map[*analysis.Analyzer]*triState)
+ for _, a := range analyzers {
+ var prefix string
+
+ // Add -analysis.enable flag.
+ if multi {
+ prefix = a.Name + "."
+
+ enable := new(triState)
+ enableName := prefix + "enable"
+ enableUsage := "enable " + a.Name + " analysis"
+ flag.Var(enable, enableName, enableUsage)
+ enabled[a] = enable
+ analysisFlags = append(analysisFlags, analysisFlag{enableName, true, enableUsage})
+ }
+
+ a.Flags.VisitAll(func(f *flag.Flag) {
+ if !multi && flag.Lookup(f.Name) != nil {
+ log.Printf("%s flag -%s would conflict with driver; skipping", a.Name, f.Name)
+ return
+ }
+
+ name := prefix + f.Name
+ flag.Var(f.Value, name, f.Usage)
+
+ var isBool bool
+ if b, ok := f.Value.(interface{ IsBoolFlag() bool }); ok {
+ isBool = b.IsBoolFlag()
+ }
+ analysisFlags = append(analysisFlags, analysisFlag{name, isBool, f.Usage})
+ })
+ }
+
+ // standard flags: -flags, -V.
+ printflags := flag.Bool("flags", false, "print analyzer flags in JSON")
+ addVersionFlag()
+
+ flag.Parse() // (ExitOnError)
+
+ // -flags: print flags so that go vet knows which ones are legitimate.
+ if *printflags {
+ data, err := json.MarshalIndent(analysisFlags, "", "\t")
+ if err != nil {
+ log.Fatal(err)
+ }
+ os.Stdout.Write(data)
+ os.Exit(0)
+ }
+
+ // If any --foo.enable flag is true, run only those analyzers. Otherwise,
+ // if any --foo.enable flag is false, run all but those analyzers.
+ if multi {
+ var hasTrue, hasFalse bool
+ for _, ts := range enabled {
+ switch *ts {
+ case setTrue:
+ hasTrue = true
+ case setFalse:
+ hasFalse = true
+ }
+ }
+
+ var keep []*analysis.Analyzer
+ if hasTrue {
+ for _, a := range analyzers {
+ if *enabled[a] == setTrue {
+ keep = append(keep, a)
+ }
+ }
+ analyzers = keep
+ } else if hasFalse {
+ for _, a := range analyzers {
+ if *enabled[a] != setFalse {
+ keep = append(keep, a)
+ }
+ }
+ analyzers = keep
+ }
+ }
+
+ return analyzers
+}
+
+// addVersionFlag registers a -V flag that, if set,
+// prints the executable version and exits 0.
+//
+// It is a variable not a function to permit easy
+// overriding in the copy vendored in $GOROOT/src/cmd/vet:
+//
+// func init() { addVersionFlag = objabi.AddVersionFlag }
+var addVersionFlag = func() {
+ flag.Var(versionFlag{}, "V", "print version and exit")
+}
+
+// versionFlag minimally complies with the -V protocol required by "go vet".
+type versionFlag struct{}
+
+func (versionFlag) IsBoolFlag() bool { return true }
+func (versionFlag) Get() interface{} { return nil }
+func (versionFlag) String() string { return "" }
+func (versionFlag) Set(s string) error {
+ if s != "full" {
+ log.Fatalf("unsupported flag value: -V=%s", s)
+ }
+
+ // This replicates the miminal subset of
+ // cmd/internal/objabi.AddVersionFlag, which is private to the
+ // go tool yet forms part of our command-line interface.
+ // TODO(adonovan): clarify the contract.
+
+ // Print the tool version so the build system can track changes.
+ // Formats:
+ // $progname version devel ... buildID=...
+ // $progname version go1.9.1
+ progname := os.Args[0]
+ f, err := os.Open(progname)
+ if err != nil {
+ log.Fatal(err)
+ }
+ h := sha256.New()
+ if _, err := io.Copy(h, f); err != nil {
+ log.Fatal(err)
+ }
+ f.Close()
+ fmt.Printf("%s version devel comments-go-here buildID=%02x\n",
+ progname, string(h.Sum(nil)))
+ os.Exit(0)
+ return nil
+}
+
+// A triState is a boolean that knows whether
+// it has been set to either true or false.
+// It is used to identify whether a flag appears;
+// the standard boolean flag cannot
+// distinguish missing from unset.
+// It also satisfies flag.Value.
+type triState int
+
+const (
+ unset triState = iota
+ setTrue
+ setFalse
+)
+
+func triStateFlag(name string, value triState, usage string) *triState {
+ flag.Var(&value, name, usage)
+ return &value
+}
+
+// triState implements flag.Value, flag.Getter, and flag.boolFlag.
+// They work like boolean flags: we can say vet -printf as well as vet -printf=true
+func (ts *triState) Get() interface{} {
+ return *ts == setTrue
+}
+
+func (ts triState) isTrue() bool {
+ return ts == setTrue
+}
+
+func (ts *triState) Set(value string) error {
+ b, err := strconv.ParseBool(value)
+ if err != nil {
+ // This error message looks poor but package "flag" adds
+ // "invalid boolean value %q for -foo.enable: %s"
+ return fmt.Errorf("want true or false")
+ }
+ if b {
+ *ts = setTrue
+ } else {
+ *ts = setFalse
+ }
+ return nil
+}
+
+func (ts *triState) String() string {
+ switch *ts {
+ case unset:
+ return "true"
+ case setTrue:
+ return "true"
+ case setFalse:
+ return "false"
+ }
+ panic("not reached")
+}
+
+func (ts triState) IsBoolFlag() bool {
+ return true
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package facts defines a serializable set of analysis.Fact.
+//
+// It provides a partial implementation of the Fact-related parts of the
+// analysis.Pass interface for use in analysis drivers such as "go vet"
+// and other build systems.
+//
+// The serial format is unspecified and may change, so the same version
+// of this package must be used for reading and writing serialized facts.
+//
+// The handling of facts in the analysis system parallels the handling
+// of type information in the compiler: during compilation of package P,
+// the compiler emits an export data file that describes the type of
+// every object (named thing) defined in package P, plus every object
+// indirectly reachable from one of those objects. Thus the downstream
+// compiler of package Q need only load one export data file per direct
+// import of Q, and it will learn everything about the API of package P
+// and everything it needs to know about the API of P's dependencies.
+//
+// Similarly, analysis of package P emits a fact set containing facts
+// about all objects exported from P, plus additional facts about only
+// those objects of P's dependencies that are reachable from the API of
+// package P; the downstream analysis of Q need only load one fact set
+// per direct import of Q.
+//
+// The notion of "exportedness" that matters here is that of the
+// compiler. According to the language spec, a method pkg.T.f is
+// unexported simply because its name starts with lowercase. But the
+// compiler must nonethless export f so that downstream compilations can
+// accurately ascertain whether pkg.T implements an interface pkg.I
+// defined as interface{f()}. Exported thus means "described in export
+// data".
+//
+package facts
+
+import (
+ "bytes"
+ "encoding/gob"
+ "fmt"
+ "go/types"
+ "io/ioutil"
+ "log"
+ "reflect"
+ "sort"
+ "sync"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/types/objectpath"
+)
+
+const debug = false
+
+// A Set is a set of analysis.Facts.
+//
+// Decode creates a Set of facts by reading from the imports of a given
+// package, and Encode writes out the set. Between these operation,
+// the Import and Export methods will query and update the set.
+//
+// All of Set's methods except String are safe to call concurrently.
+type Set struct {
+ pkg *types.Package
+ mu sync.Mutex
+ m map[key]analysis.Fact
+}
+
+type key struct {
+ pkg *types.Package
+ obj types.Object // (object facts only)
+ t reflect.Type
+}
+
+// ImportObjectFact implements analysis.Pass.ImportObjectFact.
+func (s *Set) ImportObjectFact(obj types.Object, ptr analysis.Fact) bool {
+ if obj == nil {
+ panic("nil object")
+ }
+ key := key{pkg: obj.Pkg(), obj: obj, t: reflect.TypeOf(ptr)}
+ s.mu.Lock()
+ defer s.mu.Unlock()
+ if v, ok := s.m[key]; ok {
+ reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
+ return true
+ }
+ return false
+}
+
+// ExportObjectFact implements analysis.Pass.ExportObjectFact.
+func (s *Set) ExportObjectFact(obj types.Object, fact analysis.Fact) {
+ if obj.Pkg() != s.pkg {
+ log.Panicf("in package %s: ExportObjectFact(%s, %T): can't set fact on object belonging another package",
+ s.pkg, obj, fact)
+ }
+ key := key{pkg: obj.Pkg(), obj: obj, t: reflect.TypeOf(fact)}
+ s.mu.Lock()
+ s.m[key] = fact // clobber any existing entry
+ s.mu.Unlock()
+}
+
+// ImportPackageFact implements analysis.Pass.ImportPackageFact.
+func (s *Set) ImportPackageFact(pkg *types.Package, ptr analysis.Fact) bool {
+ if pkg == nil {
+ panic("nil package")
+ }
+ key := key{pkg: pkg, t: reflect.TypeOf(ptr)}
+ s.mu.Lock()
+ defer s.mu.Unlock()
+ if v, ok := s.m[key]; ok {
+ reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
+ return true
+ }
+ return false
+}
+
+// ExportPackageFact implements analysis.Pass.ExportPackageFact.
+func (s *Set) ExportPackageFact(fact analysis.Fact) {
+ key := key{pkg: s.pkg, t: reflect.TypeOf(fact)}
+ s.mu.Lock()
+ s.m[key] = fact // clobber any existing entry
+ s.mu.Unlock()
+}
+
+// gobFact is the Gob declaration of a serialized fact.
+type gobFact struct {
+ PkgPath string // path of package
+ Object objectpath.Path // optional path of object relative to package itself
+ Fact analysis.Fact // type and value of user-defined Fact
+}
+
+// Decode decodes all the facts relevant to the analysis of package pkg.
+// The read function reads serialized fact data from an external source
+// for one of of pkg's direct imports. The empty file is a valid
+// encoding of an empty fact set.
+//
+// It is the caller's responsibility to call gob.Register on all
+// necessary fact types.
+func Decode(pkg *types.Package, read func(packagePath string) ([]byte, error)) (*Set, error) {
+ // Compute the import map for this package.
+ // See the package doc comment.
+ packages := importMap(pkg.Imports())
+
+ // Read facts from imported packages.
+ // Facts may describe indirectly imported packages, or their objects.
+ m := make(map[key]analysis.Fact) // one big bucket
+ for _, imp := range pkg.Imports() {
+ logf := func(format string, args ...interface{}) {
+ if debug {
+ prefix := fmt.Sprintf("in %s, importing %s: ",
+ pkg.Path(), imp.Path())
+ log.Print(prefix, fmt.Sprintf(format, args...))
+ }
+ }
+
+ // Read the gob-encoded facts.
+ data, err := read(imp.Path())
+ if err != nil {
+ return nil, fmt.Errorf("in %s, can't import facts for package %q: %v",
+ pkg.Path(), imp.Path(), err)
+ }
+ if len(data) == 0 {
+ continue // no facts
+ }
+ var gobFacts []gobFact
+ if err := gob.NewDecoder(bytes.NewReader(data)).Decode(&gobFacts); err != nil {
+ return nil, fmt.Errorf("decoding facts for %q: %v", imp.Path(), err)
+ }
+ if debug {
+ logf("decoded %d facts: %v", len(gobFacts), gobFacts)
+ }
+
+ // Parse each one into a key and a Fact.
+ for _, f := range gobFacts {
+ factPkg := packages[f.PkgPath]
+ if factPkg == nil {
+ // Fact relates to a dependency that was
+ // unused in this translation unit. Skip.
+ logf("no package %q; discarding %v", f.PkgPath, f.Fact)
+ continue
+ }
+ key := key{pkg: factPkg, t: reflect.TypeOf(f.Fact)}
+ if f.Object != "" {
+ // object fact
+ obj, err := objectpath.Object(factPkg, f.Object)
+ if err != nil {
+ // (most likely due to unexported object)
+ // TODO(adonovan): audit for other possibilities.
+ logf("no object for path: %v; discarding %s", err, f.Fact)
+ continue
+ }
+ key.obj = obj
+ logf("read %T fact %s for %v", f.Fact, f.Fact, key.obj)
+ } else {
+ // package fact
+ logf("read %T fact %s for %v", f.Fact, f.Fact, factPkg)
+ }
+ m[key] = f.Fact
+ }
+ }
+
+ return &Set{pkg: pkg, m: m}, nil
+}
+
+// Encode encodes a set of facts to a memory buffer.
+//
+// It may fail if one of the Facts could not be gob-encoded, but this is
+// a sign of a bug in an Analyzer.
+func (s *Set) Encode() []byte {
+
+ // TODO(adonovan): opt: use a more efficient encoding
+ // that avoids repeating PkgPath for each fact.
+
+ // Gather all facts, including those from imported packages.
+ var gobFacts []gobFact
+
+ s.mu.Lock()
+ for k, fact := range s.m {
+ if debug {
+ log.Printf("%v => %s\n", k, fact)
+ }
+ var object objectpath.Path
+ if k.obj != nil {
+ path, err := objectpath.For(k.obj)
+ if err != nil {
+ if debug {
+ log.Printf("discarding fact %s about %s\n", fact, k.obj)
+ }
+ continue // object not accessible from package API; discard fact
+ }
+ object = path
+ }
+ gobFacts = append(gobFacts, gobFact{
+ PkgPath: k.pkg.Path(),
+ Object: object,
+ Fact: fact,
+ })
+ }
+ s.mu.Unlock()
+
+ // Sort facts by (package, object, type) for determinism.
+ sort.Slice(gobFacts, func(i, j int) bool {
+ x, y := gobFacts[i], gobFacts[j]
+ if x.PkgPath != y.PkgPath {
+ return x.PkgPath < y.PkgPath
+ }
+ if x.Object != y.Object {
+ return x.Object < y.Object
+ }
+ tx := reflect.TypeOf(x.Fact)
+ ty := reflect.TypeOf(y.Fact)
+ if tx != ty {
+ return tx.String() < ty.String()
+ }
+ return false // equal
+ })
+
+ var buf bytes.Buffer
+ if len(gobFacts) > 0 {
+ if err := gob.NewEncoder(&buf).Encode(gobFacts); err != nil {
+ // Fact encoding should never fail. Identify the culprit.
+ for _, gf := range gobFacts {
+ if err := gob.NewEncoder(ioutil.Discard).Encode(gf); err != nil {
+ fact := gf.Fact
+ pkgpath := reflect.TypeOf(fact).Elem().PkgPath()
+ log.Panicf("internal error: gob encoding of analysis fact %s failed: %v; please report a bug against fact %T in package %q",
+ fact, err, fact, pkgpath)
+ }
+ }
+ }
+ }
+
+ if debug {
+ log.Printf("package %q: encode %d facts, %d bytes\n",
+ s.pkg.Path(), len(gobFacts), buf.Len())
+ }
+
+ return buf.Bytes()
+}
+
+// String is provided only for debugging, and must not be called
+// concurrent with any Import/Export method.
+func (s *Set) String() string {
+ var buf bytes.Buffer
+ buf.WriteString("{")
+ for k, f := range s.m {
+ if buf.Len() > 1 {
+ buf.WriteString(", ")
+ }
+ if k.obj != nil {
+ buf.WriteString(k.obj.String())
+ } else {
+ buf.WriteString(k.pkg.Path())
+ }
+ fmt.Fprintf(&buf, ": %v", f)
+ }
+ buf.WriteString("}")
+ return buf.String()
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package facts
+
+import "go/types"
+
+// importMap computes the import map for a package by traversing the
+// entire exported API each of its imports.
+//
+// This is a workaround for the fact that we cannot access the map used
+// internally by the types.Importer returned by go/importer. The entries
+// in this map are the packages and objects that may be relevant to the
+// current analysis unit.
+//
+// Packages in the map that are only indirectly imported may be
+// incomplete (!pkg.Complete()).
+//
+func importMap(imports []*types.Package) map[string]*types.Package {
+ objects := make(map[types.Object]bool)
+ packages := make(map[string]*types.Package)
+
+ var addObj func(obj types.Object) bool
+ var addType func(T types.Type)
+
+ addObj = func(obj types.Object) bool {
+ if !objects[obj] {
+ objects[obj] = true
+ addType(obj.Type())
+ if pkg := obj.Pkg(); pkg != nil {
+ packages[pkg.Path()] = pkg
+ }
+ return true
+ }
+ return false
+ }
+
+ addType = func(T types.Type) {
+ switch T := T.(type) {
+ case *types.Basic:
+ // nop
+ case *types.Named:
+ if addObj(T.Obj()) {
+ for i := 0; i < T.NumMethods(); i++ {
+ addObj(T.Method(i))
+ }
+ }
+ case *types.Pointer:
+ addType(T.Elem())
+ case *types.Slice:
+ addType(T.Elem())
+ case *types.Array:
+ addType(T.Elem())
+ case *types.Chan:
+ addType(T.Elem())
+ case *types.Map:
+ addType(T.Key())
+ addType(T.Elem())
+ case *types.Signature:
+ addType(T.Params())
+ addType(T.Results())
+ case *types.Struct:
+ for i := 0; i < T.NumFields(); i++ {
+ addObj(T.Field(i))
+ }
+ case *types.Tuple:
+ for i := 0; i < T.Len(); i++ {
+ addObj(T.At(i))
+ }
+ case *types.Interface:
+ for i := 0; i < T.NumMethods(); i++ {
+ addObj(T.Method(i))
+ }
+ }
+ }
+
+ for _, imp := range imports {
+ packages[imp.Path()] = imp
+
+ scope := imp.Scope()
+ for _, name := range scope.Names() {
+ addObj(scope.Lookup(name))
+ }
+ }
+
+ return packages
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The unitchecker package defines the main function for an analysis
+// driver that analyzes a single compilation unit during a build.
+// It is invoked by a build system such as "go vet":
+//
+// $ GOVETTOOL=$(which vet) go vet
+//
+// It supports the following command-line protocol:
+//
+// -V=full describe executable (to the build tool)
+// -flags describe flags (to the build tool)
+// foo.cfg description of compilation unit (from the build tool)
+//
+// This package does not depend on go/packages.
+// If you need a standalone tool, use multichecker,
+// which supports this mode but can also load packages
+// from source using go/packages.
+package unitchecker
+
+// TODO(adonovan):
+// - with gccgo, go build does not build standard library,
+// so we will not get to analyze it. Yet we must in order
+// to create base facts for, say, the fmt package for the
+// printf checker.
+// - support JSON output, factored with multichecker.
+
+import (
+ "encoding/gob"
+ "encoding/json"
+ "fmt"
+ "go/ast"
+ "go/build"
+ "go/importer"
+ "go/parser"
+ "go/token"
+ "go/types"
+ "io"
+ "io/ioutil"
+ "log"
+ "os"
+ "sort"
+ "strings"
+ "sync"
+ "time"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/internal/facts"
+)
+
+// A Config describes a compilation unit to be analyzed.
+// It is provided to the tool in a JSON-encoded file
+// whose name ends with ".cfg".
+type Config struct {
+ Compiler string
+ Dir string
+ ImportPath string
+ GoFiles []string
+ OtherFiles []string // TODO(adonovan): make go vet populate this (github.com/golang/go/issues/27665)
+ ImportMap map[string]string
+ PackageFile map[string]string
+ Standard map[string]bool
+ PackageVetx map[string]string
+ VetxOnly bool
+ VetxOutput string
+ SucceedOnTypecheckFailure bool
+}
+
+// Main reads the *.cfg file, runs the analysis,
+// and calls os.Exit with an appropriate error code.
+func Main(configFile string, analyzers []*analysis.Analyzer) {
+ cfg, err := readConfig(configFile)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ fset := token.NewFileSet()
+ diags, err := run(fset, cfg, analyzers)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ if len(diags) > 0 {
+ for _, diag := range diags {
+ fmt.Fprintf(os.Stderr, "%s: %s\n", fset.Position(diag.Pos), diag.Message)
+ }
+ os.Exit(1)
+ }
+
+ os.Exit(0)
+}
+
+func readConfig(filename string) (*Config, error) {
+ data, err := ioutil.ReadFile(filename)
+ if err != nil {
+ return nil, err
+ }
+ cfg := new(Config)
+ if err := json.Unmarshal(data, cfg); err != nil {
+ return nil, fmt.Errorf("cannot decode JSON config file %s: %v", filename, err)
+ }
+ if len(cfg.GoFiles) == 0 {
+ // The go command disallows packages with no files.
+ // The only exception is unsafe, but the go command
+ // doesn't call vet on it.
+ return nil, fmt.Errorf("package has no files: %s", cfg.ImportPath)
+ }
+ return cfg, nil
+}
+
+func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]analysis.Diagnostic, error) {
+ // Load, parse, typecheck.
+ var files []*ast.File
+ for _, name := range cfg.GoFiles {
+ f, err := parser.ParseFile(fset, name, nil, parser.ParseComments)
+ if err != nil {
+ if cfg.SucceedOnTypecheckFailure {
+ // Silently succeed; let the compiler
+ // report parse errors.
+ err = nil
+ }
+ return nil, err
+ }
+ files = append(files, f)
+ }
+ compilerImporter := importer.For(cfg.Compiler, func(path string) (io.ReadCloser, error) {
+ // path is a resolved package path, not an import path.
+ file, ok := cfg.PackageFile[path]
+ if !ok {
+ if cfg.Compiler == "gccgo" && cfg.Standard[path] {
+ return nil, nil // fall back to default gccgo lookup
+ }
+ return nil, fmt.Errorf("no package file for %q", path)
+ }
+ return os.Open(file)
+ })
+ importer := importerFunc(func(importPath string) (*types.Package, error) {
+ path, ok := cfg.ImportMap[importPath] // resolve vendoring, etc
+ if !ok {
+ return nil, fmt.Errorf("can't resolve import %q", path)
+ }
+ return compilerImporter.Import(path)
+ })
+ tc := &types.Config{
+ Importer: importer,
+ Sizes: types.SizesFor("gc", build.Default.GOARCH), // assume gccgo ≡ gc?
+ }
+ info := &types.Info{
+ Types: make(map[ast.Expr]types.TypeAndValue),
+ Defs: make(map[*ast.Ident]types.Object),
+ Uses: make(map[*ast.Ident]types.Object),
+ Implicits: make(map[ast.Node]types.Object),
+ Scopes: make(map[ast.Node]*types.Scope),
+ Selections: make(map[*ast.SelectorExpr]*types.Selection),
+ }
+ pkg, err := tc.Check(cfg.ImportPath, fset, files, info)
+ if err != nil {
+ if cfg.SucceedOnTypecheckFailure {
+ // Silently succeed; let the compiler
+ // report type errors.
+ err = nil
+ }
+ return nil, err
+ }
+
+ // Register fact types with gob.
+ // In VetxOnly mode, analyzers are only for their facts,
+ // so we can skip any analysis that neither produces facts
+ // nor depends on any analysis that produces facts.
+ // Also build a map to hold working state and result.
+ type action struct {
+ once sync.Once
+ result interface{}
+ err error
+ usesFacts bool // (transitively uses)
+ diagnostics []analysis.Diagnostic
+ }
+ actions := make(map[*analysis.Analyzer]*action)
+ var registerFacts func(a *analysis.Analyzer) bool
+ registerFacts = func(a *analysis.Analyzer) bool {
+ act, ok := actions[a]
+ if !ok {
+ act = new(action)
+ var usesFacts bool
+ for _, f := range a.FactTypes {
+ usesFacts = true
+ gob.Register(f)
+ }
+ for _, req := range a.Requires {
+ if registerFacts(req) {
+ usesFacts = true
+ }
+ }
+ act.usesFacts = usesFacts
+ actions[a] = act
+ }
+ return act.usesFacts
+ }
+ var filtered []*analysis.Analyzer
+ for _, a := range analyzers {
+ if registerFacts(a) || !cfg.VetxOnly {
+ filtered = append(filtered, a)
+ }
+ }
+ analyzers = filtered
+
+ // Read facts from imported packages.
+ read := func(path string) ([]byte, error) {
+ if vetx, ok := cfg.PackageVetx[path]; ok {
+ return ioutil.ReadFile(vetx)
+ }
+ return nil, nil // no .vetx file, no facts
+ }
+ facts, err := facts.Decode(pkg, read)
+ if err != nil {
+ return nil, err
+ }
+
+ // In parallel, execute the DAG of analyzers.
+ var exec func(a *analysis.Analyzer) *action
+ var execAll func(analyzers []*analysis.Analyzer)
+ exec = func(a *analysis.Analyzer) *action {
+ act := actions[a]
+ act.once.Do(func() {
+ execAll(a.Requires) // prefetch dependencies in parallel
+
+ // The inputs to this analysis are the
+ // results of its prerequisites.
+ inputs := make(map[*analysis.Analyzer]interface{})
+ var failed []string
+ for _, req := range a.Requires {
+ reqact := exec(req)
+ if reqact.err != nil {
+ failed = append(failed, req.String())
+ continue
+ }
+ inputs[req] = reqact.result
+ }
+
+ // Report an error if any dependency failed.
+ if failed != nil {
+ sort.Strings(failed)
+ act.err = fmt.Errorf("failed prerequisites: %s", strings.Join(failed, ", "))
+ return
+ }
+
+ pass := &analysis.Pass{
+ Analyzer: a,
+ Fset: fset,
+ Files: files,
+ OtherFiles: cfg.OtherFiles,
+ Pkg: pkg,
+ TypesInfo: info,
+ ResultOf: inputs,
+ Report: func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
+ ImportObjectFact: facts.ImportObjectFact,
+ ExportObjectFact: facts.ExportObjectFact,
+ ImportPackageFact: facts.ImportPackageFact,
+ ExportPackageFact: facts.ExportPackageFact,
+ }
+
+ t0 := time.Now()
+ act.result, act.err = a.Run(pass)
+ if false {
+ log.Printf("analysis %s = %s", pass, time.Since(t0))
+ }
+ })
+ return act
+ }
+ execAll = func(analyzers []*analysis.Analyzer) {
+ var wg sync.WaitGroup
+ for _, a := range analyzers {
+ wg.Add(1)
+ go func(a *analysis.Analyzer) {
+ _ = exec(a)
+ wg.Done()
+ }(a)
+ }
+ wg.Wait()
+ }
+
+ execAll(analyzers)
+
+ // Return diagnostics from root analyzers.
+ var diags []analysis.Diagnostic
+ for _, a := range analyzers {
+ act := actions[a]
+ if act.err != nil {
+ return nil, act.err // some analysis failed
+ }
+ diags = append(diags, act.diagnostics...)
+ }
+
+ data := facts.Encode()
+ if err := ioutil.WriteFile(cfg.VetxOutput, data, 0666); err != nil {
+ return nil, fmt.Errorf("failed to write analysis facts: %v", err)
+ }
+
+ return diags, nil
+}
+
+type importerFunc func(path string) (*types.Package, error)
+
+func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package asmdecl defines an Analyzer that reports mismatches between
+// assembly files and Go declarations.
+package asmdecl
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/build"
+ "go/token"
+ "go/types"
+ "log"
+ "regexp"
+ "strconv"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "asmdecl",
+ Doc: "report mismatches between assembly files and Go declarations",
+ Run: run,
+}
+
+// 'kind' is a kind of assembly variable.
+// The kinds 1, 2, 4, 8 stand for values of that size.
+type asmKind int
+
+// These special kinds are not valid sizes.
+const (
+ asmString asmKind = 100 + iota
+ asmSlice
+ asmArray
+ asmInterface
+ asmEmptyInterface
+ asmStruct
+ asmComplex
+)
+
+// An asmArch describes assembly parameters for an architecture
+type asmArch struct {
+ name string
+ bigEndian bool
+ stack string
+ lr bool
+ // calculated during initialization
+ sizes types.Sizes
+ intSize int
+ ptrSize int
+ maxAlign int
+}
+
+// An asmFunc describes the expected variables for a function on a given architecture.
+type asmFunc struct {
+ arch *asmArch
+ size int // size of all arguments
+ vars map[string]*asmVar
+ varByOffset map[int]*asmVar
+}
+
+// An asmVar describes a single assembly variable.
+type asmVar struct {
+ name string
+ kind asmKind
+ typ string
+ off int
+ size int
+ inner []*asmVar
+}
+
+var (
+ asmArch386 = asmArch{name: "386", bigEndian: false, stack: "SP", lr: false}
+ asmArchArm = asmArch{name: "arm", bigEndian: false, stack: "R13", lr: true}
+ asmArchArm64 = asmArch{name: "arm64", bigEndian: false, stack: "RSP", lr: true}
+ asmArchAmd64 = asmArch{name: "amd64", bigEndian: false, stack: "SP", lr: false}
+ asmArchAmd64p32 = asmArch{name: "amd64p32", bigEndian: false, stack: "SP", lr: false}
+ asmArchMips = asmArch{name: "mips", bigEndian: true, stack: "R29", lr: true}
+ asmArchMipsLE = asmArch{name: "mipsle", bigEndian: false, stack: "R29", lr: true}
+ asmArchMips64 = asmArch{name: "mips64", bigEndian: true, stack: "R29", lr: true}
+ asmArchMips64LE = asmArch{name: "mips64le", bigEndian: false, stack: "R29", lr: true}
+ asmArchPpc64 = asmArch{name: "ppc64", bigEndian: true, stack: "R1", lr: true}
+ asmArchPpc64LE = asmArch{name: "ppc64le", bigEndian: false, stack: "R1", lr: true}
+ asmArchS390X = asmArch{name: "s390x", bigEndian: true, stack: "R15", lr: true}
+ asmArchWasm = asmArch{name: "wasm", bigEndian: false, stack: "SP", lr: false}
+
+ arches = []*asmArch{
+ &asmArch386,
+ &asmArchArm,
+ &asmArchArm64,
+ &asmArchAmd64,
+ &asmArchAmd64p32,
+ &asmArchMips,
+ &asmArchMipsLE,
+ &asmArchMips64,
+ &asmArchMips64LE,
+ &asmArchPpc64,
+ &asmArchPpc64LE,
+ &asmArchS390X,
+ &asmArchWasm,
+ }
+)
+
+func init() {
+ for _, arch := range arches {
+ arch.sizes = types.SizesFor("gc", arch.name)
+ if arch.sizes == nil {
+ // TODO(adonovan): fix: now that asmdecl is not in the standard
+ // library we cannot assume types.SizesFor is consistent with arches.
+ // For now, assume 64-bit norms and print a warning.
+ // But this warning should really be deferred until we attempt to use
+ // arch, which is very unlikely.
+ arch.sizes = types.SizesFor("gc", "amd64")
+ log.Printf("unknown architecture %s", arch.name)
+ }
+ arch.intSize = int(arch.sizes.Sizeof(types.Typ[types.Int]))
+ arch.ptrSize = int(arch.sizes.Sizeof(types.Typ[types.UnsafePointer]))
+ arch.maxAlign = int(arch.sizes.Alignof(types.Typ[types.Int64]))
+ }
+}
+
+var (
+ re = regexp.MustCompile
+ asmPlusBuild = re(`//\s+\+build\s+([^\n]+)`)
+ asmTEXT = re(`\bTEXT\b(.*)·([^\(]+)\(SB\)(?:\s*,\s*([0-9A-Z|+()]+))?(?:\s*,\s*\$(-?[0-9]+)(?:-([0-9]+))?)?`)
+ asmDATA = re(`\b(DATA|GLOBL)\b`)
+ asmNamedFP = re(`([a-zA-Z0-9_\xFF-\x{10FFFF}]+)(?:\+([0-9]+))\(FP\)`)
+ asmUnnamedFP = re(`[^+\-0-9](([0-9]+)\(FP\))`)
+ asmSP = re(`[^+\-0-9](([0-9]+)\(([A-Z0-9]+)\))`)
+ asmOpcode = re(`^\s*(?:[A-Z0-9a-z_]+:)?\s*([A-Z]+)\s*([^,]*)(?:,\s*(.*))?`)
+ ppc64Suff = re(`([BHWD])(ZU|Z|U|BR)?$`)
+)
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ // No work if no assembly files.
+ var sfiles []string
+ for _, fname := range pass.OtherFiles {
+ if strings.HasSuffix(fname, ".s") {
+ sfiles = append(sfiles, fname)
+ }
+ }
+ if sfiles == nil {
+ return nil, nil
+ }
+
+ // Gather declarations. knownFunc[name][arch] is func description.
+ knownFunc := make(map[string]map[string]*asmFunc)
+
+ for _, f := range pass.Files {
+ for _, decl := range f.Decls {
+ if decl, ok := decl.(*ast.FuncDecl); ok && decl.Body == nil {
+ knownFunc[decl.Name.Name] = asmParseDecl(pass, decl)
+ }
+ }
+ }
+
+Files:
+ for _, fname := range sfiles {
+ content, tf, err := analysisutil.ReadFile(pass.Fset, fname)
+ if err != nil {
+ return nil, err
+ }
+
+ // Determine architecture from file name if possible.
+ var arch string
+ var archDef *asmArch
+ for _, a := range arches {
+ if strings.HasSuffix(fname, "_"+a.name+".s") {
+ arch = a.name
+ archDef = a
+ break
+ }
+ }
+
+ lines := strings.SplitAfter(string(content), "\n")
+ var (
+ fn *asmFunc
+ fnName string
+ localSize, argSize int
+ wroteSP bool
+ haveRetArg bool
+ retLine []int
+ )
+
+ flushRet := func() {
+ if fn != nil && fn.vars["ret"] != nil && !haveRetArg && len(retLine) > 0 {
+ v := fn.vars["ret"]
+ for _, line := range retLine {
+ pass.Reportf(analysisutil.LineStart(tf, line), "[%s] %s: RET without writing to %d-byte ret+%d(FP)", arch, fnName, v.size, v.off)
+ }
+ }
+ retLine = nil
+ }
+ for lineno, line := range lines {
+ lineno++
+
+ badf := func(format string, args ...interface{}) {
+ pass.Reportf(analysisutil.LineStart(tf, lineno), "[%s] %s: %s", arch, fnName, fmt.Sprintf(format, args...))
+ }
+
+ if arch == "" {
+ // Determine architecture from +build line if possible.
+ if m := asmPlusBuild.FindStringSubmatch(line); m != nil {
+ // There can be multiple architectures in a single +build line,
+ // so accumulate them all and then prefer the one that
+ // matches build.Default.GOARCH.
+ var archCandidates []*asmArch
+ for _, fld := range strings.Fields(m[1]) {
+ for _, a := range arches {
+ if a.name == fld {
+ archCandidates = append(archCandidates, a)
+ }
+ }
+ }
+ for _, a := range archCandidates {
+ if a.name == build.Default.GOARCH {
+ archCandidates = []*asmArch{a}
+ break
+ }
+ }
+ if len(archCandidates) > 0 {
+ arch = archCandidates[0].name
+ archDef = archCandidates[0]
+ }
+ }
+ }
+
+ if m := asmTEXT.FindStringSubmatch(line); m != nil {
+ flushRet()
+ if arch == "" {
+ // Arch not specified by filename or build tags.
+ // Fall back to build.Default.GOARCH.
+ for _, a := range arches {
+ if a.name == build.Default.GOARCH {
+ arch = a.name
+ archDef = a
+ break
+ }
+ }
+ if arch == "" {
+ badf("%s: cannot determine architecture for assembly file")
+ continue Files
+ }
+ }
+ fnName = m[2]
+ if pkgName := strings.TrimSpace(m[1]); pkgName != "" {
+ pathParts := strings.Split(pkgName, "∕")
+ pkgName = pathParts[len(pathParts)-1]
+ if pkgName != pass.Pkg.Path() {
+ badf("[%s] cannot check cross-package assembly function: %s is in package %s", arch, fnName, pkgName)
+ fn = nil
+ fnName = ""
+ continue
+ }
+ }
+ flag := m[3]
+ fn = knownFunc[fnName][arch]
+ if fn != nil {
+ size, _ := strconv.Atoi(m[5])
+ if size != fn.size && (flag != "7" && !strings.Contains(flag, "NOSPLIT") || size != 0) {
+ badf("wrong argument size %d; expected $...-%d", size, fn.size)
+ }
+ }
+ localSize, _ = strconv.Atoi(m[4])
+ localSize += archDef.intSize
+ if archDef.lr && !strings.Contains(flag, "NOFRAME") {
+ // Account for caller's saved LR
+ localSize += archDef.intSize
+ }
+ argSize, _ = strconv.Atoi(m[5])
+ if fn == nil && !strings.Contains(fnName, "<>") {
+ badf("function %s missing Go declaration", fnName)
+ }
+ wroteSP = false
+ haveRetArg = false
+ continue
+ } else if strings.Contains(line, "TEXT") && strings.Contains(line, "SB") {
+ // function, but not visible from Go (didn't match asmTEXT), so stop checking
+ flushRet()
+ fn = nil
+ fnName = ""
+ continue
+ }
+
+ if strings.Contains(line, "RET") {
+ retLine = append(retLine, lineno)
+ }
+
+ if fnName == "" {
+ continue
+ }
+
+ if asmDATA.FindStringSubmatch(line) != nil {
+ fn = nil
+ }
+
+ if archDef == nil {
+ continue
+ }
+
+ if strings.Contains(line, ", "+archDef.stack) || strings.Contains(line, ",\t"+archDef.stack) {
+ wroteSP = true
+ continue
+ }
+
+ for _, m := range asmSP.FindAllStringSubmatch(line, -1) {
+ if m[3] != archDef.stack || wroteSP {
+ continue
+ }
+ off := 0
+ if m[1] != "" {
+ off, _ = strconv.Atoi(m[2])
+ }
+ if off >= localSize {
+ if fn != nil {
+ v := fn.varByOffset[off-localSize]
+ if v != nil {
+ badf("%s should be %s+%d(FP)", m[1], v.name, off-localSize)
+ continue
+ }
+ }
+ if off >= localSize+argSize {
+ badf("use of %s points beyond argument frame", m[1])
+ continue
+ }
+ badf("use of %s to access argument frame", m[1])
+ }
+ }
+
+ if fn == nil {
+ continue
+ }
+
+ for _, m := range asmUnnamedFP.FindAllStringSubmatch(line, -1) {
+ off, _ := strconv.Atoi(m[2])
+ v := fn.varByOffset[off]
+ if v != nil {
+ badf("use of unnamed argument %s; offset %d is %s+%d(FP)", m[1], off, v.name, v.off)
+ } else {
+ badf("use of unnamed argument %s", m[1])
+ }
+ }
+
+ for _, m := range asmNamedFP.FindAllStringSubmatch(line, -1) {
+ name := m[1]
+ off := 0
+ if m[2] != "" {
+ off, _ = strconv.Atoi(m[2])
+ }
+ if name == "ret" || strings.HasPrefix(name, "ret_") {
+ haveRetArg = true
+ }
+ v := fn.vars[name]
+ if v == nil {
+ // Allow argframe+0(FP).
+ if name == "argframe" && off == 0 {
+ continue
+ }
+ v = fn.varByOffset[off]
+ if v != nil {
+ badf("unknown variable %s; offset %d is %s+%d(FP)", name, off, v.name, v.off)
+ } else {
+ badf("unknown variable %s", name)
+ }
+ continue
+ }
+ asmCheckVar(badf, fn, line, m[0], off, v)
+ }
+ }
+ flushRet()
+ }
+ return nil, nil
+}
+
+func asmKindForType(t types.Type, size int) asmKind {
+ switch t := t.Underlying().(type) {
+ case *types.Basic:
+ switch t.Kind() {
+ case types.String:
+ return asmString
+ case types.Complex64, types.Complex128:
+ return asmComplex
+ }
+ return asmKind(size)
+ case *types.Pointer, *types.Chan, *types.Map, *types.Signature:
+ return asmKind(size)
+ case *types.Struct:
+ return asmStruct
+ case *types.Interface:
+ if t.Empty() {
+ return asmEmptyInterface
+ }
+ return asmInterface
+ case *types.Array:
+ return asmArray
+ case *types.Slice:
+ return asmSlice
+ }
+ panic("unreachable")
+}
+
+// A component is an assembly-addressable component of a composite type,
+// or a composite type itself.
+type component struct {
+ size int
+ offset int
+ kind asmKind
+ typ string
+ suffix string // Such as _base for string base, _0_lo for lo half of first element of [1]uint64 on 32 bit machine.
+ outer string // The suffix for immediately containing composite type.
+}
+
+func newComponent(suffix string, kind asmKind, typ string, offset, size int, outer string) component {
+ return component{suffix: suffix, kind: kind, typ: typ, offset: offset, size: size, outer: outer}
+}
+
+// componentsOfType generates a list of components of type t.
+// For example, given string, the components are the string itself, the base, and the length.
+func componentsOfType(arch *asmArch, t types.Type) []component {
+ return appendComponentsRecursive(arch, t, nil, "", 0)
+}
+
+// appendComponentsRecursive implements componentsOfType.
+// Recursion is required to correct handle structs and arrays,
+// which can contain arbitrary other types.
+func appendComponentsRecursive(arch *asmArch, t types.Type, cc []component, suffix string, off int) []component {
+ s := t.String()
+ size := int(arch.sizes.Sizeof(t))
+ kind := asmKindForType(t, size)
+ cc = append(cc, newComponent(suffix, kind, s, off, size, suffix))
+
+ switch kind {
+ case 8:
+ if arch.ptrSize == 4 {
+ w1, w2 := "lo", "hi"
+ if arch.bigEndian {
+ w1, w2 = w2, w1
+ }
+ cc = append(cc, newComponent(suffix+"_"+w1, 4, "half "+s, off, 4, suffix))
+ cc = append(cc, newComponent(suffix+"_"+w2, 4, "half "+s, off+4, 4, suffix))
+ }
+
+ case asmEmptyInterface:
+ cc = append(cc, newComponent(suffix+"_type", asmKind(arch.ptrSize), "interface type", off, arch.ptrSize, suffix))
+ cc = append(cc, newComponent(suffix+"_data", asmKind(arch.ptrSize), "interface data", off+arch.ptrSize, arch.ptrSize, suffix))
+
+ case asmInterface:
+ cc = append(cc, newComponent(suffix+"_itable", asmKind(arch.ptrSize), "interface itable", off, arch.ptrSize, suffix))
+ cc = append(cc, newComponent(suffix+"_data", asmKind(arch.ptrSize), "interface data", off+arch.ptrSize, arch.ptrSize, suffix))
+
+ case asmSlice:
+ cc = append(cc, newComponent(suffix+"_base", asmKind(arch.ptrSize), "slice base", off, arch.ptrSize, suffix))
+ cc = append(cc, newComponent(suffix+"_len", asmKind(arch.intSize), "slice len", off+arch.ptrSize, arch.intSize, suffix))
+ cc = append(cc, newComponent(suffix+"_cap", asmKind(arch.intSize), "slice cap", off+arch.ptrSize+arch.intSize, arch.intSize, suffix))
+
+ case asmString:
+ cc = append(cc, newComponent(suffix+"_base", asmKind(arch.ptrSize), "string base", off, arch.ptrSize, suffix))
+ cc = append(cc, newComponent(suffix+"_len", asmKind(arch.intSize), "string len", off+arch.ptrSize, arch.intSize, suffix))
+
+ case asmComplex:
+ fsize := size / 2
+ cc = append(cc, newComponent(suffix+"_real", asmKind(fsize), fmt.Sprintf("real(complex%d)", size*8), off, fsize, suffix))
+ cc = append(cc, newComponent(suffix+"_imag", asmKind(fsize), fmt.Sprintf("imag(complex%d)", size*8), off+fsize, fsize, suffix))
+
+ case asmStruct:
+ tu := t.Underlying().(*types.Struct)
+ fields := make([]*types.Var, tu.NumFields())
+ for i := 0; i < tu.NumFields(); i++ {
+ fields[i] = tu.Field(i)
+ }
+ offsets := arch.sizes.Offsetsof(fields)
+ for i, f := range fields {
+ cc = appendComponentsRecursive(arch, f.Type(), cc, suffix+"_"+f.Name(), off+int(offsets[i]))
+ }
+
+ case asmArray:
+ tu := t.Underlying().(*types.Array)
+ elem := tu.Elem()
+ // Calculate offset of each element array.
+ fields := []*types.Var{
+ types.NewVar(token.NoPos, nil, "fake0", elem),
+ types.NewVar(token.NoPos, nil, "fake1", elem),
+ }
+ offsets := arch.sizes.Offsetsof(fields)
+ elemoff := int(offsets[1])
+ for i := 0; i < int(tu.Len()); i++ {
+ cc = appendComponentsRecursive(arch, elem, cc, suffix+"_"+strconv.Itoa(i), i*elemoff)
+ }
+ }
+
+ return cc
+}
+
+// asmParseDecl parses a function decl for expected assembly variables.
+func asmParseDecl(pass *analysis.Pass, decl *ast.FuncDecl) map[string]*asmFunc {
+ var (
+ arch *asmArch
+ fn *asmFunc
+ offset int
+ )
+
+ // addParams adds asmVars for each of the parameters in list.
+ // isret indicates whether the list are the arguments or the return values.
+ // TODO(adonovan): simplify by passing (*types.Signature).{Params,Results}
+ // instead of list.
+ addParams := func(list []*ast.Field, isret bool) {
+ argnum := 0
+ for _, fld := range list {
+ t := pass.TypesInfo.Types[fld.Type].Type
+
+ // Work around github.com/golang/go/issues/28277.
+ if t == nil {
+ if ell, ok := fld.Type.(*ast.Ellipsis); ok {
+ t = types.NewSlice(pass.TypesInfo.Types[ell.Elt].Type)
+ }
+ }
+
+ align := int(arch.sizes.Alignof(t))
+ size := int(arch.sizes.Sizeof(t))
+ offset += -offset & (align - 1)
+ cc := componentsOfType(arch, t)
+
+ // names is the list of names with this type.
+ names := fld.Names
+ if len(names) == 0 {
+ // Anonymous args will be called arg, arg1, arg2, ...
+ // Similarly so for return values: ret, ret1, ret2, ...
+ name := "arg"
+ if isret {
+ name = "ret"
+ }
+ if argnum > 0 {
+ name += strconv.Itoa(argnum)
+ }
+ names = []*ast.Ident{ast.NewIdent(name)}
+ }
+ argnum += len(names)
+
+ // Create variable for each name.
+ for _, id := range names {
+ name := id.Name
+ for _, c := range cc {
+ outer := name + c.outer
+ v := asmVar{
+ name: name + c.suffix,
+ kind: c.kind,
+ typ: c.typ,
+ off: offset + c.offset,
+ size: c.size,
+ }
+ if vo := fn.vars[outer]; vo != nil {
+ vo.inner = append(vo.inner, &v)
+ }
+ fn.vars[v.name] = &v
+ for i := 0; i < v.size; i++ {
+ fn.varByOffset[v.off+i] = &v
+ }
+ }
+ offset += size
+ }
+ }
+ }
+
+ m := make(map[string]*asmFunc)
+ for _, arch = range arches {
+ fn = &asmFunc{
+ arch: arch,
+ vars: make(map[string]*asmVar),
+ varByOffset: make(map[int]*asmVar),
+ }
+ offset = 0
+ addParams(decl.Type.Params.List, false)
+ if decl.Type.Results != nil && len(decl.Type.Results.List) > 0 {
+ offset += -offset & (arch.maxAlign - 1)
+ addParams(decl.Type.Results.List, true)
+ }
+ fn.size = offset
+ m[arch.name] = fn
+ }
+
+ return m
+}
+
+// asmCheckVar checks a single variable reference.
+func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr string, off int, v *asmVar) {
+ m := asmOpcode.FindStringSubmatch(line)
+ if m == nil {
+ if !strings.HasPrefix(strings.TrimSpace(line), "//") {
+ badf("cannot find assembly opcode")
+ }
+ return
+ }
+
+ // Determine operand sizes from instruction.
+ // Typically the suffix suffices, but there are exceptions.
+ var src, dst, kind asmKind
+ op := m[1]
+ switch fn.arch.name + "." + op {
+ case "386.FMOVLP":
+ src, dst = 8, 4
+ case "arm.MOVD":
+ src = 8
+ case "arm.MOVW":
+ src = 4
+ case "arm.MOVH", "arm.MOVHU":
+ src = 2
+ case "arm.MOVB", "arm.MOVBU":
+ src = 1
+ // LEA* opcodes don't really read the second arg.
+ // They just take the address of it.
+ case "386.LEAL":
+ dst = 4
+ case "amd64.LEAQ":
+ dst = 8
+ case "amd64p32.LEAL":
+ dst = 4
+ default:
+ switch fn.arch.name {
+ case "386", "amd64":
+ if strings.HasPrefix(op, "F") && (strings.HasSuffix(op, "D") || strings.HasSuffix(op, "DP")) {
+ // FMOVDP, FXCHD, etc
+ src = 8
+ break
+ }
+ if strings.HasPrefix(op, "P") && strings.HasSuffix(op, "RD") {
+ // PINSRD, PEXTRD, etc
+ src = 4
+ break
+ }
+ if strings.HasPrefix(op, "F") && (strings.HasSuffix(op, "F") || strings.HasSuffix(op, "FP")) {
+ // FMOVFP, FXCHF, etc
+ src = 4
+ break
+ }
+ if strings.HasSuffix(op, "SD") {
+ // MOVSD, SQRTSD, etc
+ src = 8
+ break
+ }
+ if strings.HasSuffix(op, "SS") {
+ // MOVSS, SQRTSS, etc
+ src = 4
+ break
+ }
+ if strings.HasPrefix(op, "SET") {
+ // SETEQ, etc
+ src = 1
+ break
+ }
+ switch op[len(op)-1] {
+ case 'B':
+ src = 1
+ case 'W':
+ src = 2
+ case 'L':
+ src = 4
+ case 'D', 'Q':
+ src = 8
+ }
+ case "ppc64", "ppc64le":
+ // Strip standard suffixes to reveal size letter.
+ m := ppc64Suff.FindStringSubmatch(op)
+ if m != nil {
+ switch m[1][0] {
+ case 'B':
+ src = 1
+ case 'H':
+ src = 2
+ case 'W':
+ src = 4
+ case 'D':
+ src = 8
+ }
+ }
+ case "mips", "mipsle", "mips64", "mips64le":
+ switch op {
+ case "MOVB", "MOVBU":
+ src = 1
+ case "MOVH", "MOVHU":
+ src = 2
+ case "MOVW", "MOVWU", "MOVF":
+ src = 4
+ case "MOVV", "MOVD":
+ src = 8
+ }
+ case "s390x":
+ switch op {
+ case "MOVB", "MOVBZ":
+ src = 1
+ case "MOVH", "MOVHZ":
+ src = 2
+ case "MOVW", "MOVWZ", "FMOVS":
+ src = 4
+ case "MOVD", "FMOVD":
+ src = 8
+ }
+ }
+ }
+ if dst == 0 {
+ dst = src
+ }
+
+ // Determine whether the match we're holding
+ // is the first or second argument.
+ if strings.Index(line, expr) > strings.Index(line, ",") {
+ kind = dst
+ } else {
+ kind = src
+ }
+
+ vk := v.kind
+ vs := v.size
+ vt := v.typ
+ switch vk {
+ case asmInterface, asmEmptyInterface, asmString, asmSlice:
+ // allow reference to first word (pointer)
+ vk = v.inner[0].kind
+ vs = v.inner[0].size
+ vt = v.inner[0].typ
+ }
+
+ if off != v.off {
+ var inner bytes.Buffer
+ for i, vi := range v.inner {
+ if len(v.inner) > 1 {
+ fmt.Fprintf(&inner, ",")
+ }
+ fmt.Fprintf(&inner, " ")
+ if i == len(v.inner)-1 {
+ fmt.Fprintf(&inner, "or ")
+ }
+ fmt.Fprintf(&inner, "%s+%d(FP)", vi.name, vi.off)
+ }
+ badf("invalid offset %s; expected %s+%d(FP)%s", expr, v.name, v.off, inner.String())
+ return
+ }
+ if kind != 0 && kind != vk {
+ var inner bytes.Buffer
+ if len(v.inner) > 0 {
+ fmt.Fprintf(&inner, " containing")
+ for i, vi := range v.inner {
+ if i > 0 && len(v.inner) > 2 {
+ fmt.Fprintf(&inner, ",")
+ }
+ fmt.Fprintf(&inner, " ")
+ if i > 0 && i == len(v.inner)-1 {
+ fmt.Fprintf(&inner, "and ")
+ }
+ fmt.Fprintf(&inner, "%s+%d(FP)", vi.name, vi.off)
+ }
+ }
+ badf("invalid %s of %s; %s is %d-byte value%s", op, expr, vt, vs, inner.String())
+ }
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package assign defines an Analyzer that detects useless assignments.
+package assign
+
+// TODO(adonovan): check also for assignments to struct fields inside
+// methods that are on T instead of *T.
+
+import (
+ "go/ast"
+ "go/token"
+ "reflect"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for useless assignments
+
+This checker reports assignments of the form x = x or a[i] = a[i].
+These are almost always useless, and even when they aren't they are
+usually a mistake.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "assign",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.AssignStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ stmt := n.(*ast.AssignStmt)
+ if stmt.Tok != token.ASSIGN {
+ return // ignore :=
+ }
+ if len(stmt.Lhs) != len(stmt.Rhs) {
+ // If LHS and RHS have different cardinality, they can't be the same.
+ return
+ }
+ for i, lhs := range stmt.Lhs {
+ rhs := stmt.Rhs[i]
+ if analysisutil.HasSideEffects(pass.TypesInfo, lhs) ||
+ analysisutil.HasSideEffects(pass.TypesInfo, rhs) {
+ continue // expressions may not be equal
+ }
+ if reflect.TypeOf(lhs) != reflect.TypeOf(rhs) {
+ continue // short-circuit the heavy-weight gofmt check
+ }
+ le := analysisutil.Format(pass.Fset, lhs)
+ re := analysisutil.Format(pass.Fset, rhs)
+ if le == re {
+ pass.Reportf(stmt.Pos(), "self-assignment of %s to %s", re, le)
+ }
+ }
+ })
+
+ return nil, nil
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package atomic defines an Analyzer that checks for common mistakes
+// using the sync/atomic package.
+package atomic
+
+import (
+ "go/ast"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for common mistakes using the sync/atomic package
+
+The atomic checker looks for assignment statements of the form:
+
+ x = atomic.AddUint64(&x, 1)
+
+which are not atomic.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "atomic",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.AssignStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(node ast.Node) {
+ n := node.(*ast.AssignStmt)
+ if len(n.Lhs) != len(n.Rhs) {
+ return
+ }
+ if len(n.Lhs) == 1 && n.Tok == token.DEFINE {
+ return
+ }
+
+ for i, right := range n.Rhs {
+ call, ok := right.(*ast.CallExpr)
+ if !ok {
+ continue
+ }
+ sel, ok := call.Fun.(*ast.SelectorExpr)
+ if !ok {
+ continue
+ }
+ pkgIdent, _ := sel.X.(*ast.Ident)
+ pkgName, ok := pass.TypesInfo.Uses[pkgIdent].(*types.PkgName)
+ if !ok || pkgName.Imported().Path() != "sync/atomic" {
+ continue
+ }
+
+ switch sel.Sel.Name {
+ case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr":
+ checkAtomicAddAssignment(pass, n.Lhs[i], call)
+ }
+ }
+ })
+ return nil, nil
+}
+
+// checkAtomicAddAssignment walks the atomic.Add* method calls checking
+// for assigning the return value to the same variable being used in the
+// operation
+func checkAtomicAddAssignment(pass *analysis.Pass, left ast.Expr, call *ast.CallExpr) {
+ if len(call.Args) != 2 {
+ return
+ }
+ arg := call.Args[0]
+ broken := false
+
+ gofmt := func(e ast.Expr) string { return analysisutil.Format(pass.Fset, e) }
+
+ if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
+ broken = gofmt(left) == gofmt(uarg.X)
+ } else if star, ok := left.(*ast.StarExpr); ok {
+ broken = gofmt(star.X) == gofmt(arg)
+ }
+
+ if broken {
+ pass.Reportf(left.Pos(), "direct assignment to atomic value")
+ }
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package bools defines an Analyzer that detects common mistakes
+// involving boolean operators.
+package bools
+
+import (
+ "go/ast"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "bools",
+ Doc: "check for common mistakes involving boolean operators",
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.BinaryExpr)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ e := n.(*ast.BinaryExpr)
+
+ var op boolOp
+ switch e.Op {
+ case token.LOR:
+ op = or
+ case token.LAND:
+ op = and
+ default:
+ return
+ }
+
+ // TODO(adonovan): this reports n(n-1)/2 errors for an
+ // expression e||...||e of depth n. Fix.
+ // See https://github.com/golang/go/issues/28086.
+ comm := op.commutativeSets(pass.TypesInfo, e)
+ for _, exprs := range comm {
+ op.checkRedundant(pass, exprs)
+ op.checkSuspect(pass, exprs)
+ }
+ })
+ return nil, nil
+}
+
+type boolOp struct {
+ name string
+ tok token.Token // token corresponding to this operator
+ badEq token.Token // token corresponding to the equality test that should not be used with this operator
+}
+
+var (
+ or = boolOp{"or", token.LOR, token.NEQ}
+ and = boolOp{"and", token.LAND, token.EQL}
+)
+
+// commutativeSets returns all side effect free sets of
+// expressions in e that are connected by op.
+// For example, given 'a || b || f() || c || d' with the or op,
+// commutativeSets returns {{b, a}, {d, c}}.
+func (op boolOp) commutativeSets(info *types.Info, e *ast.BinaryExpr) [][]ast.Expr {
+ exprs := op.split(e)
+
+ // Partition the slice of expressions into commutative sets.
+ i := 0
+ var sets [][]ast.Expr
+ for j := 0; j <= len(exprs); j++ {
+ if j == len(exprs) || hasSideEffects(info, exprs[j]) {
+ if i < j {
+ sets = append(sets, exprs[i:j])
+ }
+ i = j + 1
+ }
+ }
+
+ return sets
+}
+
+// checkRedundant checks for expressions of the form
+// e && e
+// e || e
+// Exprs must contain only side effect free expressions.
+func (op boolOp) checkRedundant(pass *analysis.Pass, exprs []ast.Expr) {
+ seen := make(map[string]bool)
+ for _, e := range exprs {
+ efmt := analysisutil.Format(pass.Fset, e)
+ if seen[efmt] {
+ pass.Reportf(e.Pos(), "redundant %s: %s %s %s", op.name, efmt, op.tok, efmt)
+ } else {
+ seen[efmt] = true
+ }
+ }
+}
+
+// checkSuspect checks for expressions of the form
+// x != c1 || x != c2
+// x == c1 && x == c2
+// where c1 and c2 are constant expressions.
+// If c1 and c2 are the same then it's redundant;
+// if c1 and c2 are different then it's always true or always false.
+// Exprs must contain only side effect free expressions.
+func (op boolOp) checkSuspect(pass *analysis.Pass, exprs []ast.Expr) {
+ // seen maps from expressions 'x' to equality expressions 'x != c'.
+ seen := make(map[string]string)
+
+ for _, e := range exprs {
+ bin, ok := e.(*ast.BinaryExpr)
+ if !ok || bin.Op != op.badEq {
+ continue
+ }
+
+ // In order to avoid false positives, restrict to cases
+ // in which one of the operands is constant. We're then
+ // interested in the other operand.
+ // In the rare case in which both operands are constant
+ // (e.g. runtime.GOOS and "windows"), we'll only catch
+ // mistakes if the LHS is repeated, which is how most
+ // code is written.
+ var x ast.Expr
+ switch {
+ case pass.TypesInfo.Types[bin.Y].Value != nil:
+ x = bin.X
+ case pass.TypesInfo.Types[bin.X].Value != nil:
+ x = bin.Y
+ default:
+ continue
+ }
+
+ // e is of the form 'x != c' or 'x == c'.
+ xfmt := analysisutil.Format(pass.Fset, x)
+ efmt := analysisutil.Format(pass.Fset, e)
+ if prev, found := seen[xfmt]; found {
+ // checkRedundant handles the case in which efmt == prev.
+ if efmt != prev {
+ pass.Reportf(e.Pos(), "suspect %s: %s %s %s", op.name, efmt, op.tok, prev)
+ }
+ } else {
+ seen[xfmt] = efmt
+ }
+ }
+}
+
+// hasSideEffects reports whether evaluation of e has side effects.
+func hasSideEffects(info *types.Info, e ast.Expr) bool {
+ safe := true
+ ast.Inspect(e, func(node ast.Node) bool {
+ switch n := node.(type) {
+ case *ast.CallExpr:
+ typVal := info.Types[n.Fun]
+ switch {
+ case typVal.IsType():
+ // Type conversion, which is safe.
+ case typVal.IsBuiltin():
+ // Builtin func, conservatively assumed to not
+ // be safe for now.
+ safe = false
+ return false
+ default:
+ // A non-builtin func or method call.
+ // Conservatively assume that all of them have
+ // side effects for now.
+ safe = false
+ return false
+ }
+ case *ast.UnaryExpr:
+ if n.Op == token.ARROW {
+ safe = false
+ return false
+ }
+ }
+ return true
+ })
+ return !safe
+}
+
+// split returns a slice of all subexpressions in e that are connected by op.
+// For example, given 'a || (b || c) || d' with the or op,
+// split returns []{d, c, b, a}.
+func (op boolOp) split(e ast.Expr) (exprs []ast.Expr) {
+ for {
+ e = unparen(e)
+ if b, ok := e.(*ast.BinaryExpr); ok && b.Op == op.tok {
+ exprs = append(exprs, op.split(b.Y)...)
+ e = b.X
+ } else {
+ exprs = append(exprs, e)
+ break
+ }
+ }
+ return
+}
+
+// unparen returns e with any enclosing parentheses stripped.
+func unparen(e ast.Expr) ast.Expr {
+ for {
+ p, ok := e.(*ast.ParenExpr)
+ if !ok {
+ return e
+ }
+ e = p.X
+ }
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package buildtag defines an Analyzer that checks build tags.
+package buildtag
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "strings"
+ "unicode"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "buildtag",
+ Doc: "check that +build tags are well-formed and correctly located",
+ Run: runBuildTag,
+}
+
+func runBuildTag(pass *analysis.Pass) (interface{}, error) {
+ for _, f := range pass.Files {
+ checkGoFile(pass, f)
+ }
+ for _, name := range pass.OtherFiles {
+ if err := checkOtherFile(pass, name); err != nil {
+ return nil, err
+ }
+ }
+ return nil, nil
+}
+
+func checkGoFile(pass *analysis.Pass, f *ast.File) {
+ pastCutoff := false
+ for _, group := range f.Comments {
+ // A +build comment is ignored after or adjoining the package declaration.
+ if group.End()+1 >= f.Package {
+ pastCutoff = true
+ }
+
+ // "+build" is ignored within or after a /*...*/ comment.
+ if !strings.HasPrefix(group.List[0].Text, "//") {
+ pastCutoff = true
+ continue
+ }
+
+ // Check each line of a //-comment.
+ for _, c := range group.List {
+ if !strings.Contains(c.Text, "+build") {
+ continue
+ }
+ if err := checkLine(c.Text, pastCutoff); err != nil {
+ pass.Reportf(c.Pos(), "%s", err)
+ }
+ }
+ }
+}
+
+func checkOtherFile(pass *analysis.Pass, filename string) error {
+ content, tf, err := analysisutil.ReadFile(pass.Fset, filename)
+ if err != nil {
+ return err
+ }
+
+ // We must look at the raw lines, as build tags may appear in non-Go
+ // files such as assembly files.
+ lines := bytes.SplitAfter(content, nl)
+
+ // Determine cutpoint where +build comments are no longer valid.
+ // They are valid in leading // comments in the file followed by
+ // a blank line.
+ //
+ // This must be done as a separate pass because of the
+ // requirement that the comment be followed by a blank line.
+ var cutoff int
+ for i, line := range lines {
+ line = bytes.TrimSpace(line)
+ if !bytes.HasPrefix(line, slashSlash) {
+ if len(line) > 0 {
+ break
+ }
+ cutoff = i
+ }
+ }
+
+ for i, line := range lines {
+ line = bytes.TrimSpace(line)
+ if !bytes.HasPrefix(line, slashSlash) {
+ continue
+ }
+ if !bytes.Contains(line, []byte("+build")) {
+ continue
+ }
+ if err := checkLine(string(line), i >= cutoff); err != nil {
+ pass.Reportf(analysisutil.LineStart(tf, i+1), "%s", err)
+ continue
+ }
+ }
+ return nil
+}
+
+// checkLine checks a line that starts with "//" and contains "+build".
+func checkLine(line string, pastCutoff bool) error {
+ line = strings.TrimPrefix(line, "//")
+ line = strings.TrimSpace(line)
+
+ if strings.HasPrefix(line, "+build") {
+ fields := strings.Fields(line)
+ if fields[0] != "+build" {
+ // Comment is something like +buildasdf not +build.
+ return fmt.Errorf("possible malformed +build comment")
+ }
+ if pastCutoff {
+ return fmt.Errorf("+build comment must appear before package clause and be followed by a blank line")
+ }
+ if err := checkArguments(fields); err != nil {
+ return err
+ }
+ } else {
+ // Comment with +build but not at beginning.
+ if !pastCutoff {
+ return fmt.Errorf("possible malformed +build comment")
+ }
+ }
+ return nil
+}
+
+func checkArguments(fields []string) error {
+ // The original version of this checker in vet could examine
+ // files with malformed build tags that would cause the file to
+ // be always ignored by "go build". However, drivers for the new
+ // analysis API will analyze only the files selected to form a
+ // package, so these checks will never fire.
+ // TODO(adonovan): rethink this.
+
+ for _, arg := range fields[1:] {
+ for _, elem := range strings.Split(arg, ",") {
+ if strings.HasPrefix(elem, "!!") {
+ return fmt.Errorf("invalid double negative in build constraint: %s", arg)
+ }
+ elem = strings.TrimPrefix(elem, "!")
+ for _, c := range elem {
+ if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' && c != '.' {
+ return fmt.Errorf("invalid non-alphanumeric build constraint: %s", arg)
+ }
+ }
+ }
+ }
+ return nil
+}
+
+var (
+ nl = []byte("\n")
+ slashSlash = []byte("//")
+)
--- /dev/null
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package cgocall defines an Analyzer that detects some violations of
+// the cgo pointer passing rules.
+package cgocall
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "go/types"
+ "log"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `detect some violations of the cgo pointer passing rules
+
+Check for invalid cgo pointer passing.
+This looks for code that uses cgo to call C code passing values
+whose types are almost always invalid according to the cgo pointer
+sharing rules.
+Specifically, it warns about attempts to pass a Go chan, map, func,
+or slice to C, either directly, or via a pointer, array, or struct.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "cgocall",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.CallExpr)(nil),
+ }
+ inspect.WithStack(nodeFilter, func(n ast.Node, push bool, stack []ast.Node) bool {
+ if !push {
+ return true
+ }
+ call, name := findCall(pass.Fset, stack)
+ if call == nil {
+ return true // not a call we need to check
+ }
+
+ // A call to C.CBytes passes a pointer but is always safe.
+ if name == "CBytes" {
+ return true
+ }
+
+ if false {
+ fmt.Printf("%s: inner call to C.%s\n", pass.Fset.Position(n.Pos()), name)
+ fmt.Printf("%s: outer call to C.%s\n", pass.Fset.Position(call.Lparen), name)
+ }
+
+ for _, arg := range call.Args {
+ if !typeOKForCgoCall(cgoBaseType(pass.TypesInfo, arg), make(map[types.Type]bool)) {
+ pass.Reportf(arg.Pos(), "possibly passing Go type with embedded pointer to C")
+ break
+ }
+
+ // Check for passing the address of a bad type.
+ if conv, ok := arg.(*ast.CallExpr); ok && len(conv.Args) == 1 &&
+ isUnsafePointer(pass.TypesInfo, conv.Fun) {
+ arg = conv.Args[0]
+ }
+ if u, ok := arg.(*ast.UnaryExpr); ok && u.Op == token.AND {
+ if !typeOKForCgoCall(cgoBaseType(pass.TypesInfo, u.X), make(map[types.Type]bool)) {
+ pass.Reportf(arg.Pos(), "possibly passing Go type with embedded pointer to C")
+ break
+ }
+ }
+ }
+ return true
+ })
+ return nil, nil
+}
+
+// findCall returns the CallExpr that we need to check, which may not be
+// the same as the one we're currently visiting, due to code generation.
+// It also returns the name of the function, such as "f" for C.f(...).
+//
+// This checker was initially written in vet to inpect unprocessed cgo
+// source files using partial type information. However, Analyzers in
+// the new analysis API are presented with the type-checked, processed
+// Go ASTs resulting from cgo processing files, so we must choose
+// between:
+//
+// a) locating the cgo file (e.g. from //line directives)
+// and working with that, or
+// b) working with the file generated by cgo.
+//
+// We cannot use (a) because it does not provide type information, which
+// the analyzer needs, and it is infeasible for the analyzer to run the
+// type checker on this file. Thus we choose (b), which is fragile,
+// because the checker may need to change each time the cgo processor
+// changes.
+//
+// Consider a cgo source file containing this header:
+//
+// /* void f(void *x, *y); */
+// import "C"
+//
+// The cgo tool expands a call such as:
+//
+// C.f(x, y)
+//
+// to this:
+//
+// 1 func(param0, param1 unsafe.Pointer) {
+// 2 ... various checks on params ...
+// 3 (_Cfunc_f)(param0, param1)
+// 4 }(x, y)
+//
+// We first locate the _Cfunc_f call on line 3, then
+// walk up the stack of enclosing nodes until we find
+// the call on line 4.
+//
+func findCall(fset *token.FileSet, stack []ast.Node) (*ast.CallExpr, string) {
+ last := len(stack) - 1
+ call := stack[last].(*ast.CallExpr)
+ if id, ok := analysisutil.Unparen(call.Fun).(*ast.Ident); ok {
+ if name := strings.TrimPrefix(id.Name, "_Cfunc_"); name != id.Name {
+ // Find the outer call with the arguments (x, y) we want to check.
+ for i := last - 1; i >= 0; i-- {
+ if outer, ok := stack[i].(*ast.CallExpr); ok {
+ return outer, name
+ }
+ }
+ // This shouldn't happen.
+ // Perhaps the code generator has changed?
+ log.Printf("%s: can't find outer call for C.%s(...)",
+ fset.Position(call.Lparen), name)
+ }
+ }
+ return nil, ""
+}
+
+// cgoBaseType tries to look through type conversions involving
+// unsafe.Pointer to find the real type. It converts:
+// unsafe.Pointer(x) => x
+// *(*unsafe.Pointer)(unsafe.Pointer(&x)) => x
+func cgoBaseType(info *types.Info, arg ast.Expr) types.Type {
+ switch arg := arg.(type) {
+ case *ast.CallExpr:
+ if len(arg.Args) == 1 && isUnsafePointer(info, arg.Fun) {
+ return cgoBaseType(info, arg.Args[0])
+ }
+ case *ast.StarExpr:
+ call, ok := arg.X.(*ast.CallExpr)
+ if !ok || len(call.Args) != 1 {
+ break
+ }
+ // Here arg is *f(v).
+ t := info.Types[call.Fun].Type
+ if t == nil {
+ break
+ }
+ ptr, ok := t.Underlying().(*types.Pointer)
+ if !ok {
+ break
+ }
+ // Here arg is *(*p)(v)
+ elem, ok := ptr.Elem().Underlying().(*types.Basic)
+ if !ok || elem.Kind() != types.UnsafePointer {
+ break
+ }
+ // Here arg is *(*unsafe.Pointer)(v)
+ call, ok = call.Args[0].(*ast.CallExpr)
+ if !ok || len(call.Args) != 1 {
+ break
+ }
+ // Here arg is *(*unsafe.Pointer)(f(v))
+ if !isUnsafePointer(info, call.Fun) {
+ break
+ }
+ // Here arg is *(*unsafe.Pointer)(unsafe.Pointer(v))
+ u, ok := call.Args[0].(*ast.UnaryExpr)
+ if !ok || u.Op != token.AND {
+ break
+ }
+ // Here arg is *(*unsafe.Pointer)(unsafe.Pointer(&v))
+ return cgoBaseType(info, u.X)
+ }
+
+ return info.Types[arg].Type
+}
+
+// typeOKForCgoCall reports whether the type of arg is OK to pass to a
+// C function using cgo. This is not true for Go types with embedded
+// pointers. m is used to avoid infinite recursion on recursive types.
+func typeOKForCgoCall(t types.Type, m map[types.Type]bool) bool {
+ if t == nil || m[t] {
+ return true
+ }
+ m[t] = true
+ switch t := t.Underlying().(type) {
+ case *types.Chan, *types.Map, *types.Signature, *types.Slice:
+ return false
+ case *types.Pointer:
+ return typeOKForCgoCall(t.Elem(), m)
+ case *types.Array:
+ return typeOKForCgoCall(t.Elem(), m)
+ case *types.Struct:
+ for i := 0; i < t.NumFields(); i++ {
+ if !typeOKForCgoCall(t.Field(i).Type(), m) {
+ return false
+ }
+ }
+ }
+ return true
+}
+
+func isUnsafePointer(info *types.Info, e ast.Expr) bool {
+ t := info.Types[e].Type
+ return t != nil && t.Underlying() == types.Typ[types.UnsafePointer]
+}
--- /dev/null
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package composite defines an Analyzer that checks for unkeyed
+// composite literals.
+package composite
+
+import (
+ "go/ast"
+ "go/types"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `checked for unkeyed composite literals
+
+This analyzer reports a diagnostic for composite literals of struct
+types imported from another package that do not use the field-keyed
+syntax. Such literals are fragile because the addition of a new field
+(even if unexported) to the struct will cause compilation to fail.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "composites",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+var whitelist = true
+
+func init() {
+ Analyzer.Flags.BoolVar(&whitelist, "whitelist", whitelist, "use composite white list; for testing only")
+}
+
+// runUnkeyedLiteral checks if a composite literal is a struct literal with
+// unkeyed fields.
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.CompositeLit)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ cl := n.(*ast.CompositeLit)
+
+ typ := pass.TypesInfo.Types[cl].Type
+ if typ == nil {
+ // cannot determine composite literals' type, skip it
+ return
+ }
+ typeName := typ.String()
+ if whitelist && unkeyedLiteral[typeName] {
+ // skip whitelisted types
+ return
+ }
+ under := typ.Underlying()
+ for {
+ ptr, ok := under.(*types.Pointer)
+ if !ok {
+ break
+ }
+ under = ptr.Elem().Underlying()
+ }
+ if _, ok := under.(*types.Struct); !ok {
+ // skip non-struct composite literals
+ return
+ }
+ if isLocalType(pass, typ) {
+ // allow unkeyed locally defined composite literal
+ return
+ }
+
+ // check if the CompositeLit contains an unkeyed field
+ allKeyValue := true
+ for _, e := range cl.Elts {
+ if _, ok := e.(*ast.KeyValueExpr); !ok {
+ allKeyValue = false
+ break
+ }
+ }
+ if allKeyValue {
+ // all the composite literal fields are keyed
+ return
+ }
+
+ pass.Reportf(cl.Pos(), "%s composite literal uses unkeyed fields", typeName)
+ })
+ return nil, nil
+}
+
+func isLocalType(pass *analysis.Pass, typ types.Type) bool {
+ switch x := typ.(type) {
+ case *types.Struct:
+ // struct literals are local types
+ return true
+ case *types.Pointer:
+ return isLocalType(pass, x.Elem())
+ case *types.Named:
+ // names in package foo are local to foo_test too
+ return strings.TrimSuffix(x.Obj().Pkg().Path(), "_test") == strings.TrimSuffix(pass.Pkg.Path(), "_test")
+ }
+ return false
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package composite
+
+// unkeyedLiteral is a white list of types in the standard packages
+// that are used with unkeyed literals we deem to be acceptable.
+var unkeyedLiteral = map[string]bool{
+ // These image and image/color struct types are frozen. We will never add fields to them.
+ "image/color.Alpha16": true,
+ "image/color.Alpha": true,
+ "image/color.CMYK": true,
+ "image/color.Gray16": true,
+ "image/color.Gray": true,
+ "image/color.NRGBA64": true,
+ "image/color.NRGBA": true,
+ "image/color.NYCbCrA": true,
+ "image/color.RGBA64": true,
+ "image/color.RGBA": true,
+ "image/color.YCbCr": true,
+ "image.Point": true,
+ "image.Rectangle": true,
+ "image.Uniform": true,
+
+ "unicode.Range16": true,
+
+ // These three structs are used in generated test main files,
+ // but the generator can be trusted.
+ "testing.InternalBenchmark": true,
+ "testing.InternalExample": true,
+ "testing.InternalTest": true,
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package copylock defines an Analyzer that checks for locks
+// erroneously passed by value.
+package copylock
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for locks erroneously passed by value
+
+Inadvertently copying a value containing a lock, such as sync.Mutex or
+sync.WaitGroup, may cause both copies to malfunction. Generally such
+values should be referred to through a pointer.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "copylocks",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.AssignStmt)(nil),
+ (*ast.CallExpr)(nil),
+ (*ast.CompositeLit)(nil),
+ (*ast.FuncDecl)(nil),
+ (*ast.FuncLit)(nil),
+ (*ast.GenDecl)(nil),
+ (*ast.RangeStmt)(nil),
+ (*ast.ReturnStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(node ast.Node) {
+ switch node := node.(type) {
+ case *ast.RangeStmt:
+ checkCopyLocksRange(pass, node)
+ case *ast.FuncDecl:
+ checkCopyLocksFunc(pass, node.Name.Name, node.Recv, node.Type)
+ case *ast.FuncLit:
+ checkCopyLocksFunc(pass, "func", nil, node.Type)
+ case *ast.CallExpr:
+ checkCopyLocksCallExpr(pass, node)
+ case *ast.AssignStmt:
+ checkCopyLocksAssign(pass, node)
+ case *ast.GenDecl:
+ checkCopyLocksGenDecl(pass, node)
+ case *ast.CompositeLit:
+ checkCopyLocksCompositeLit(pass, node)
+ case *ast.ReturnStmt:
+ checkCopyLocksReturnStmt(pass, node)
+ }
+ })
+ return nil, nil
+}
+
+// checkCopyLocksAssign checks whether an assignment
+// copies a lock.
+func checkCopyLocksAssign(pass *analysis.Pass, as *ast.AssignStmt) {
+ for i, x := range as.Rhs {
+ if path := lockPathRhs(pass, x); path != nil {
+ pass.Reportf(x.Pos(), "assignment copies lock value to %v: %v", analysisutil.Format(pass.Fset, as.Lhs[i]), path)
+ }
+ }
+}
+
+// checkCopyLocksGenDecl checks whether lock is copied
+// in variable declaration.
+func checkCopyLocksGenDecl(pass *analysis.Pass, gd *ast.GenDecl) {
+ if gd.Tok != token.VAR {
+ return
+ }
+ for _, spec := range gd.Specs {
+ valueSpec := spec.(*ast.ValueSpec)
+ for i, x := range valueSpec.Values {
+ if path := lockPathRhs(pass, x); path != nil {
+ pass.Reportf(x.Pos(), "variable declaration copies lock value to %v: %v", valueSpec.Names[i].Name, path)
+ }
+ }
+ }
+}
+
+// checkCopyLocksCompositeLit detects lock copy inside a composite literal
+func checkCopyLocksCompositeLit(pass *analysis.Pass, cl *ast.CompositeLit) {
+ for _, x := range cl.Elts {
+ if node, ok := x.(*ast.KeyValueExpr); ok {
+ x = node.Value
+ }
+ if path := lockPathRhs(pass, x); path != nil {
+ pass.Reportf(x.Pos(), "literal copies lock value from %v: %v", analysisutil.Format(pass.Fset, x), path)
+ }
+ }
+}
+
+// checkCopyLocksReturnStmt detects lock copy in return statement
+func checkCopyLocksReturnStmt(pass *analysis.Pass, rs *ast.ReturnStmt) {
+ for _, x := range rs.Results {
+ if path := lockPathRhs(pass, x); path != nil {
+ pass.Reportf(x.Pos(), "return copies lock value: %v", path)
+ }
+ }
+}
+
+// checkCopyLocksCallExpr detects lock copy in the arguments to a function call
+func checkCopyLocksCallExpr(pass *analysis.Pass, ce *ast.CallExpr) {
+ var id *ast.Ident
+ switch fun := ce.Fun.(type) {
+ case *ast.Ident:
+ id = fun
+ case *ast.SelectorExpr:
+ id = fun.Sel
+ }
+ if fun, ok := pass.TypesInfo.Uses[id].(*types.Builtin); ok {
+ switch fun.Name() {
+ case "new", "len", "cap", "Sizeof":
+ return
+ }
+ }
+ for _, x := range ce.Args {
+ if path := lockPathRhs(pass, x); path != nil {
+ pass.Reportf(x.Pos(), "call of %s copies lock value: %v", analysisutil.Format(pass.Fset, ce.Fun), path)
+ }
+ }
+}
+
+// checkCopyLocksFunc checks whether a function might
+// inadvertently copy a lock, by checking whether
+// its receiver, parameters, or return values
+// are locks.
+func checkCopyLocksFunc(pass *analysis.Pass, name string, recv *ast.FieldList, typ *ast.FuncType) {
+ if recv != nil && len(recv.List) > 0 {
+ expr := recv.List[0].Type
+ if path := lockPath(pass.Pkg, pass.TypesInfo.Types[expr].Type); path != nil {
+ pass.Reportf(expr.Pos(), "%s passes lock by value: %v", name, path)
+ }
+ }
+
+ if typ.Params != nil {
+ for _, field := range typ.Params.List {
+ expr := field.Type
+ if path := lockPath(pass.Pkg, pass.TypesInfo.Types[expr].Type); path != nil {
+ pass.Reportf(expr.Pos(), "%s passes lock by value: %v", name, path)
+ }
+ }
+ }
+
+ // Don't check typ.Results. If T has a Lock field it's OK to write
+ // return T{}
+ // because that is returning the zero value. Leave result checking
+ // to the return statement.
+}
+
+// checkCopyLocksRange checks whether a range statement
+// might inadvertently copy a lock by checking whether
+// any of the range variables are locks.
+func checkCopyLocksRange(pass *analysis.Pass, r *ast.RangeStmt) {
+ checkCopyLocksRangeVar(pass, r.Tok, r.Key)
+ checkCopyLocksRangeVar(pass, r.Tok, r.Value)
+}
+
+func checkCopyLocksRangeVar(pass *analysis.Pass, rtok token.Token, e ast.Expr) {
+ if e == nil {
+ return
+ }
+ id, isId := e.(*ast.Ident)
+ if isId && id.Name == "_" {
+ return
+ }
+
+ var typ types.Type
+ if rtok == token.DEFINE {
+ if !isId {
+ return
+ }
+ obj := pass.TypesInfo.Defs[id]
+ if obj == nil {
+ return
+ }
+ typ = obj.Type()
+ } else {
+ typ = pass.TypesInfo.Types[e].Type
+ }
+
+ if typ == nil {
+ return
+ }
+ if path := lockPath(pass.Pkg, typ); path != nil {
+ pass.Reportf(e.Pos(), "range var %s copies lock: %v", analysisutil.Format(pass.Fset, e), path)
+ }
+}
+
+type typePath []types.Type
+
+// String pretty-prints a typePath.
+func (path typePath) String() string {
+ n := len(path)
+ var buf bytes.Buffer
+ for i := range path {
+ if i > 0 {
+ fmt.Fprint(&buf, " contains ")
+ }
+ // The human-readable path is in reverse order, outermost to innermost.
+ fmt.Fprint(&buf, path[n-i-1].String())
+ }
+ return buf.String()
+}
+
+func lockPathRhs(pass *analysis.Pass, x ast.Expr) typePath {
+ if _, ok := x.(*ast.CompositeLit); ok {
+ return nil
+ }
+ if _, ok := x.(*ast.CallExpr); ok {
+ // A call may return a zero value.
+ return nil
+ }
+ if star, ok := x.(*ast.StarExpr); ok {
+ if _, ok := star.X.(*ast.CallExpr); ok {
+ // A call may return a pointer to a zero value.
+ return nil
+ }
+ }
+ return lockPath(pass.Pkg, pass.TypesInfo.Types[x].Type)
+}
+
+// lockPath returns a typePath describing the location of a lock value
+// contained in typ. If there is no contained lock, it returns nil.
+func lockPath(tpkg *types.Package, typ types.Type) typePath {
+ if typ == nil {
+ return nil
+ }
+
+ for {
+ atyp, ok := typ.Underlying().(*types.Array)
+ if !ok {
+ break
+ }
+ typ = atyp.Elem()
+ }
+
+ // We're only interested in the case in which the underlying
+ // type is a struct. (Interfaces and pointers are safe to copy.)
+ styp, ok := typ.Underlying().(*types.Struct)
+ if !ok {
+ return nil
+ }
+
+ // We're looking for cases in which a pointer to this type
+ // is a sync.Locker, but a value is not. This differentiates
+ // embedded interfaces from embedded values.
+ if types.Implements(types.NewPointer(typ), lockerType) && !types.Implements(typ, lockerType) {
+ return []types.Type{typ}
+ }
+
+ // In go1.10, sync.noCopy did not implement Locker.
+ // (The Unlock method was added only in CL 121876.)
+ // TODO(adonovan): remove workaround when we drop go1.10.
+ if named, ok := typ.(*types.Named); ok &&
+ named.Obj().Name() == "noCopy" &&
+ named.Obj().Pkg().Path() == "sync" {
+ return []types.Type{typ}
+ }
+
+ nfields := styp.NumFields()
+ for i := 0; i < nfields; i++ {
+ ftyp := styp.Field(i).Type()
+ subpath := lockPath(tpkg, ftyp)
+ if subpath != nil {
+ return append(subpath, typ)
+ }
+ }
+
+ return nil
+}
+
+var lockerType *types.Interface
+
+// Construct a sync.Locker interface type.
+func init() {
+ nullary := types.NewSignature(nil, nil, nil, false) // func()
+ methods := []*types.Func{
+ types.NewFunc(token.NoPos, nil, "Lock", nullary),
+ types.NewFunc(token.NoPos, nil, "Unlock", nullary),
+ }
+ lockerType = types.NewInterface(methods, nil).Complete()
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package ctrlflow is an analysis that provides a syntactic
+// control-flow graph (CFG) for the body of a function.
+// It records whether a function cannot return.
+// By itself, it does not report any diagnostics.
+package ctrlflow
+
+import (
+ "go/ast"
+ "go/types"
+ "log"
+ "reflect"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+ "golang.org/x/tools/go/cfg"
+ "golang.org/x/tools/go/types/typeutil"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "ctrlflow",
+ Doc: "build a control-flow graph",
+ Run: run,
+ ResultType: reflect.TypeOf(new(CFGs)),
+ FactTypes: []analysis.Fact{new(noReturn)},
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+}
+
+// noReturn is a fact indicating that a function does not return.
+type noReturn struct{}
+
+func (*noReturn) AFact() {}
+
+func (*noReturn) String() string { return "noReturn" }
+
+// A CFGs holds the control-flow graphs
+// for all the functions of the current package.
+type CFGs struct {
+ defs map[*ast.Ident]types.Object // from Pass.TypesInfo.Defs
+ funcDecls map[*types.Func]*declInfo
+ funcLits map[*ast.FuncLit]*litInfo
+ pass *analysis.Pass // transient; nil after construction
+}
+
+// CFGs has two maps: funcDecls for named functions and funcLits for
+// unnamed ones. Unlike funcLits, the funcDecls map is not keyed by its
+// syntax node, *ast.FuncDecl, because callMayReturn needs to do a
+// look-up by *types.Func, and you can get from an *ast.FuncDecl to a
+// *types.Func but not the other way.
+
+type declInfo struct {
+ decl *ast.FuncDecl
+ cfg *cfg.CFG // iff decl.Body != nil
+ started bool // to break cycles
+ noReturn bool
+}
+
+type litInfo struct {
+ cfg *cfg.CFG
+ noReturn bool
+}
+
+// FuncDecl returns the control-flow graph for a named function.
+// It returns nil if decl.Body==nil.
+func (c *CFGs) FuncDecl(decl *ast.FuncDecl) *cfg.CFG {
+ if decl.Body == nil {
+ return nil
+ }
+ fn := c.defs[decl.Name].(*types.Func)
+ return c.funcDecls[fn].cfg
+}
+
+// FuncLit returns the control-flow graph for a literal function.
+func (c *CFGs) FuncLit(lit *ast.FuncLit) *cfg.CFG {
+ return c.funcLits[lit].cfg
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ // Because CFG construction consumes and produces noReturn
+ // facts, CFGs for exported FuncDecls must be built before 'run'
+ // returns; we cannot construct them lazily.
+ // (We could build CFGs for FuncLits lazily,
+ // but the benefit is marginal.)
+
+ // Pass 1. Map types.Funcs to ast.FuncDecls in this package.
+ funcDecls := make(map[*types.Func]*declInfo) // functions and methods
+ funcLits := make(map[*ast.FuncLit]*litInfo)
+
+ var decls []*types.Func // keys(funcDecls), in order
+ var lits []*ast.FuncLit // keys(funcLits), in order
+
+ nodeFilter := []ast.Node{
+ (*ast.FuncDecl)(nil),
+ (*ast.FuncLit)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ switch n := n.(type) {
+ case *ast.FuncDecl:
+ fn := pass.TypesInfo.Defs[n.Name].(*types.Func)
+ funcDecls[fn] = &declInfo{decl: n}
+ decls = append(decls, fn)
+
+ case *ast.FuncLit:
+ funcLits[n] = new(litInfo)
+ lits = append(lits, n)
+ }
+ })
+
+ c := &CFGs{
+ defs: pass.TypesInfo.Defs,
+ funcDecls: funcDecls,
+ funcLits: funcLits,
+ pass: pass,
+ }
+
+ // Pass 2. Build CFGs.
+
+ // Build CFGs for named functions.
+ // Cycles in the static call graph are broken
+ // arbitrarily but deterministically.
+ // We create noReturn facts as discovered.
+ for _, fn := range decls {
+ c.buildDecl(fn, funcDecls[fn])
+ }
+
+ // Build CFGs for literal functions.
+ // These aren't relevant to facts (since they aren't named)
+ // but are required for the CFGs.FuncLit API.
+ for _, lit := range lits {
+ li := funcLits[lit]
+ if li.cfg == nil {
+ li.cfg = cfg.New(lit.Body, c.callMayReturn)
+ if !hasReachableReturn(li.cfg) {
+ li.noReturn = true
+ }
+ }
+ }
+
+ // All CFGs are now built.
+ c.pass = nil
+
+ return c, nil
+}
+
+// di.cfg may be nil on return.
+func (c *CFGs) buildDecl(fn *types.Func, di *declInfo) {
+ // buildDecl may call itself recursively for the same function,
+ // because cfg.New is passed the callMayReturn method, which
+ // builds the CFG of the callee, leading to recursion.
+ // The buildDecl call tree thus resembles the static call graph.
+ // We mark each node when we start working on it to break cycles.
+
+ if !di.started { // break cycle
+ di.started = true
+
+ if isIntrinsicNoReturn(fn) {
+ di.noReturn = true
+ }
+ if di.decl.Body != nil {
+ di.cfg = cfg.New(di.decl.Body, c.callMayReturn)
+ if !hasReachableReturn(di.cfg) {
+ di.noReturn = true
+ }
+ }
+ if di.noReturn {
+ c.pass.ExportObjectFact(fn, new(noReturn))
+ }
+
+ // debugging
+ if false {
+ log.Printf("CFG for %s:\n%s (noreturn=%t)\n", fn, di.cfg.Format(c.pass.Fset), di.noReturn)
+ }
+ }
+}
+
+// callMayReturn reports whether the called function may return.
+// It is passed to the CFG builder.
+func (c *CFGs) callMayReturn(call *ast.CallExpr) (r bool) {
+ if id, ok := call.Fun.(*ast.Ident); ok && c.pass.TypesInfo.Uses[id] == panicBuiltin {
+ return false // panic never returns
+ }
+
+ // Is this a static call?
+ fn := typeutil.StaticCallee(c.pass.TypesInfo, call)
+ if fn == nil {
+ return true // callee not statically known; be conservative
+ }
+
+ // Function or method declared in this package?
+ if di, ok := c.funcDecls[fn]; ok {
+ c.buildDecl(fn, di)
+ return !di.noReturn
+ }
+
+ // Not declared in this package.
+ // Is there a fact from another package?
+ return !c.pass.ImportObjectFact(fn, new(noReturn))
+}
+
+var panicBuiltin = types.Universe.Lookup("panic").(*types.Builtin)
+
+func hasReachableReturn(g *cfg.CFG) bool {
+ for _, b := range g.Blocks {
+ if b.Live && b.Return() != nil {
+ return true
+ }
+ }
+ return false
+}
+
+// isIntrinsicNoReturn reports whether a function intrinsically never
+// returns because it stops execution of the calling thread.
+// It is the base case in the recursion.
+func isIntrinsicNoReturn(fn *types.Func) bool {
+ // Add functions here as the need arises, but don't allocate memory.
+ path, name := fn.Pkg().Path(), fn.Name()
+ return path == "syscall" && (name == "Exit" || name == "ExitProcess" || name == "ExitThread") ||
+ path == "runtime" && name == "Goexit"
+}
--- /dev/null
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package httpresponse defines an Analyzer that checks for mistakes
+// using HTTP responses.
+package httpresponse
+
+import (
+ "go/ast"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for mistakes using HTTP responses
+
+A common mistake when using the net/http package is to defer a function
+call to close the http.Response Body before checking the error that
+determines whether the response is valid:
+
+ resp, err := http.Head(url)
+ defer resp.Body.Close()
+ if err != nil {
+ log.Fatal(err)
+ }
+ // (defer statement belongs here)
+
+This checker helps uncover latent nil dereference bugs by reporting a
+diagnostic for such mistakes.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "httpresponse",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ // Fast path: if the package doesn't import net/http,
+ // skip the traversal.
+ if !imports(pass.Pkg, "net/http") {
+ return nil, nil
+ }
+
+ nodeFilter := []ast.Node{
+ (*ast.CallExpr)(nil),
+ }
+ inspect.WithStack(nodeFilter, func(n ast.Node, push bool, stack []ast.Node) bool {
+ if !push {
+ return true
+ }
+ call := n.(*ast.CallExpr)
+ if !isHTTPFuncOrMethodOnClient(pass.TypesInfo, call) {
+ return true // the function call is not related to this check.
+ }
+
+ // Find the innermost containing block, and get the list
+ // of statements starting with the one containing call.
+ stmts := restOfBlock(stack)
+ if len(stmts) < 2 {
+ return true // the call to the http function is the last statement of the block.
+ }
+
+ asg, ok := stmts[0].(*ast.AssignStmt)
+ if !ok {
+ return true // the first statement is not assignment.
+ }
+ resp := rootIdent(asg.Lhs[0])
+ if resp == nil {
+ return true // could not find the http.Response in the assignment.
+ }
+
+ def, ok := stmts[1].(*ast.DeferStmt)
+ if !ok {
+ return true // the following statement is not a defer.
+ }
+ root := rootIdent(def.Call.Fun)
+ if root == nil {
+ return true // could not find the receiver of the defer call.
+ }
+
+ if resp.Obj == root.Obj {
+ pass.Reportf(root.Pos(), "using %s before checking for errors", resp.Name)
+ }
+ return true
+ })
+ return nil, nil
+}
+
+// isHTTPFuncOrMethodOnClient checks whether the given call expression is on
+// either a function of the net/http package or a method of http.Client that
+// returns (*http.Response, error).
+func isHTTPFuncOrMethodOnClient(info *types.Info, expr *ast.CallExpr) bool {
+ fun, _ := expr.Fun.(*ast.SelectorExpr)
+ sig, _ := info.Types[fun].Type.(*types.Signature)
+ if sig == nil {
+ return false // the call is not of the form x.f()
+ }
+
+ res := sig.Results()
+ if res.Len() != 2 {
+ return false // the function called does not return two values.
+ }
+ if ptr, ok := res.At(0).Type().(*types.Pointer); !ok || !isNamedType(ptr.Elem(), "net/http", "Response") {
+ return false // the first return type is not *http.Response.
+ }
+
+ errorType := types.Universe.Lookup("error").Type()
+ if !types.Identical(res.At(1).Type(), errorType) {
+ return false // the second return type is not error
+ }
+
+ typ := info.Types[fun.X].Type
+ if typ == nil {
+ id, ok := fun.X.(*ast.Ident)
+ return ok && id.Name == "http" // function in net/http package.
+ }
+
+ if isNamedType(typ, "net/http", "Client") {
+ return true // method on http.Client.
+ }
+ ptr, ok := typ.(*types.Pointer)
+ return ok && isNamedType(ptr.Elem(), "net/http", "Client") // method on *http.Client.
+}
+
+// restOfBlock, given a traversal stack, finds the innermost containing
+// block and returns the suffix of its statements starting with the
+// current node (the last element of stack).
+func restOfBlock(stack []ast.Node) []ast.Stmt {
+ for i := len(stack) - 1; i >= 0; i-- {
+ if b, ok := stack[i].(*ast.BlockStmt); ok {
+ for j, v := range b.List {
+ if v == stack[i+1] {
+ return b.List[j:]
+ }
+ }
+ break
+ }
+ }
+ return nil
+}
+
+// rootIdent finds the root identifier x in a chain of selections x.y.z, or nil if not found.
+func rootIdent(n ast.Node) *ast.Ident {
+ switch n := n.(type) {
+ case *ast.SelectorExpr:
+ return rootIdent(n.X)
+ case *ast.Ident:
+ return n
+ default:
+ return nil
+ }
+}
+
+// isNamedType reports whether t is the named type path.name.
+func isNamedType(t types.Type, path, name string) bool {
+ n, ok := t.(*types.Named)
+ if !ok {
+ return false
+ }
+ obj := n.Obj()
+ return obj.Name() == name && obj.Pkg() != nil && obj.Pkg().Path() == path
+}
+
+func imports(pkg *types.Package, path string) bool {
+ for _, imp := range pkg.Imports() {
+ if imp.Path() == path {
+ return true
+ }
+ }
+ return false
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package inspect defines an Analyzer that provides an AST inspector
+// (golang.org/x/tools/go/ast/inspect.Inspect) for the syntax trees of a
+// package. It is only a building block for other analyzers.
+//
+// Example of use in another analysis:
+//
+// import "golang.org/x/tools/go/analysis/passes/inspect"
+//
+// var Analyzer = &analysis.Analyzer{
+// ...
+// Requires: reflect.TypeOf(new(inspect.Analyzer)),
+// }
+//
+// func run(pass *analysis.Pass) (interface{}, error) {
+// inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+// inspect.Preorder(nil, func(n ast.Node) {
+// ...
+// })
+// return nil
+// }
+//
+package inspect
+
+import (
+ "reflect"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "inspect",
+ Doc: "optimize AST traversal for later passes",
+ Run: run,
+ RunDespiteErrors: true,
+ ResultType: reflect.TypeOf(new(inspector.Inspector)),
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ return inspector.New(pass.Files), nil
+}
--- /dev/null
+// Package analysisutil defines various helper functions
+// used by two or more packages beneath go/analysis.
+package analysisutil
+
+import (
+ "bytes"
+ "go/ast"
+ "go/printer"
+ "go/token"
+ "go/types"
+ "io/ioutil"
+)
+
+// Format returns a string representation of the expression.
+func Format(fset *token.FileSet, x ast.Expr) string {
+ var b bytes.Buffer
+ printer.Fprint(&b, fset, x)
+ return b.String()
+}
+
+// HasSideEffects reports whether evaluation of e has side effects.
+func HasSideEffects(info *types.Info, e ast.Expr) bool {
+ safe := true
+ ast.Inspect(e, func(node ast.Node) bool {
+ switch n := node.(type) {
+ case *ast.CallExpr:
+ typVal := info.Types[n.Fun]
+ switch {
+ case typVal.IsType():
+ // Type conversion, which is safe.
+ case typVal.IsBuiltin():
+ // Builtin func, conservatively assumed to not
+ // be safe for now.
+ safe = false
+ return false
+ default:
+ // A non-builtin func or method call.
+ // Conservatively assume that all of them have
+ // side effects for now.
+ safe = false
+ return false
+ }
+ case *ast.UnaryExpr:
+ if n.Op == token.ARROW {
+ safe = false
+ return false
+ }
+ }
+ return true
+ })
+ return !safe
+}
+
+// Unparen returns e with any enclosing parentheses stripped.
+func Unparen(e ast.Expr) ast.Expr {
+ for {
+ p, ok := e.(*ast.ParenExpr)
+ if !ok {
+ return e
+ }
+ e = p.X
+ }
+}
+
+// ReadFile reads a file and adds it to the FileSet
+// so that we can report errors against it using lineStart.
+func ReadFile(fset *token.FileSet, filename string) ([]byte, *token.File, error) {
+ content, err := ioutil.ReadFile(filename)
+ if err != nil {
+ return nil, nil, err
+ }
+ tf := fset.AddFile(filename, -1, len(content))
+ tf.SetLinesForContent(content)
+ return content, tf, nil
+}
+
+// LineStart returns the position of the start of the specified line
+// within file f, or NoPos if there is no line of that number.
+func LineStart(f *token.File, line int) token.Pos {
+ // Use binary search to find the start offset of this line.
+ //
+ // TODO(adonovan): eventually replace this function with the
+ // simpler and more efficient (*go/token.File).LineStart, added
+ // in go1.12.
+
+ min := 0 // inclusive
+ max := f.Size() // exclusive
+ for {
+ offset := (min + max) / 2
+ pos := f.Pos(offset)
+ posn := f.Position(pos)
+ if posn.Line == line {
+ return pos - (token.Pos(posn.Column) - 1)
+ }
+
+ if min+1 >= max {
+ return token.NoPos
+ }
+
+ if posn.Line < line {
+ min = offset
+ } else {
+ max = offset
+ }
+ }
+}
--- /dev/null
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package loopclosure defines an Analyzer that checks for references to
+// enclosing loop variables from within nested functions.
+package loopclosure
+
+import (
+ "go/ast"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+// TODO(adonovan): also report an error for the following structure,
+// which is often used to ensure that deferred calls do not accumulate
+// in a loop:
+//
+// for i, x := range c {
+// func() {
+// ...reference to i or x...
+// }()
+// }
+
+const Doc = `check references to loop variables from within nested functions
+
+This analyzer checks for references to loop variables from within a
+function literal inside the loop body. It checks only instances where
+the function literal is called in a defer or go statement that is the
+last statement in the loop body, as otherwise we would need whole
+program analysis.
+
+For example:
+
+ for i, v := range s {
+ go func() {
+ println(i, v) // not what you might expect
+ }()
+ }
+
+See: https://golang.org/doc/go_faq.html#closures_and_goroutines`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "loopclosure",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.RangeStmt)(nil),
+ (*ast.ForStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ // Find the variables updated by the loop statement.
+ var vars []*ast.Ident
+ addVar := func(expr ast.Expr) {
+ if id, ok := expr.(*ast.Ident); ok {
+ vars = append(vars, id)
+ }
+ }
+ var body *ast.BlockStmt
+ switch n := n.(type) {
+ case *ast.RangeStmt:
+ body = n.Body
+ addVar(n.Key)
+ addVar(n.Value)
+ case *ast.ForStmt:
+ body = n.Body
+ switch post := n.Post.(type) {
+ case *ast.AssignStmt:
+ // e.g. for p = head; p != nil; p = p.next
+ for _, lhs := range post.Lhs {
+ addVar(lhs)
+ }
+ case *ast.IncDecStmt:
+ // e.g. for i := 0; i < n; i++
+ addVar(post.X)
+ }
+ }
+ if vars == nil {
+ return
+ }
+
+ // Inspect a go or defer statement
+ // if it's the last one in the loop body.
+ // (We give up if there are following statements,
+ // because it's hard to prove go isn't followed by wait,
+ // or defer by return.)
+ if len(body.List) == 0 {
+ return
+ }
+ var last *ast.CallExpr
+ switch s := body.List[len(body.List)-1].(type) {
+ case *ast.GoStmt:
+ last = s.Call
+ case *ast.DeferStmt:
+ last = s.Call
+ default:
+ return
+ }
+ lit, ok := last.Fun.(*ast.FuncLit)
+ if !ok {
+ return
+ }
+ ast.Inspect(lit.Body, func(n ast.Node) bool {
+ id, ok := n.(*ast.Ident)
+ if !ok || id.Obj == nil {
+ return true
+ }
+ if pass.TypesInfo.Types[id].Type == nil {
+ // Not referring to a variable (e.g. struct field name)
+ return true
+ }
+ for _, v := range vars {
+ if v.Obj == id.Obj {
+ pass.Reportf(id.Pos(), "loop variable %s captured by func literal",
+ id.Name)
+ }
+ }
+ return true
+ })
+ })
+ return nil, nil
+}
--- /dev/null
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package lostcancel defines an Analyzer that checks for failure to
+// call a context cancelation function.
+package lostcancel
+
+import (
+ "fmt"
+ "go/ast"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/ctrlflow"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+ "golang.org/x/tools/go/cfg"
+)
+
+const Doc = `check cancel func returned by context.WithCancel is called
+
+The cancelation function returned by context.WithCancel, WithTimeout,
+and WithDeadline must be called or the new context will remain live
+until its parent context is cancelled.
+(The background context is never cancelled.)`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "lostcancel",
+ Doc: Doc,
+ Run: run,
+ Requires: []*analysis.Analyzer{
+ inspect.Analyzer,
+ ctrlflow.Analyzer,
+ },
+}
+
+const debug = false
+
+var contextPackage = "context"
+
+// checkLostCancel reports a failure to the call the cancel function
+// returned by context.WithCancel, either because the variable was
+// assigned to the blank identifier, or because there exists a
+// control-flow path from the call to a return statement and that path
+// does not "use" the cancel function. Any reference to the variable
+// counts as a use, even within a nested function literal.
+//
+// checkLostCancel analyzes a single named or literal function.
+func run(pass *analysis.Pass) (interface{}, error) {
+ // Fast path: bypass check if file doesn't use context.WithCancel.
+ if !hasImport(pass.Pkg, contextPackage) {
+ return nil, nil
+ }
+
+ // Call runFunc for each Func{Decl,Lit}.
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+ nodeTypes := []ast.Node{
+ (*ast.FuncLit)(nil),
+ (*ast.FuncDecl)(nil),
+ }
+ inspect.Preorder(nodeTypes, func(n ast.Node) {
+ runFunc(pass, n)
+ })
+ return nil, nil
+}
+
+func runFunc(pass *analysis.Pass, node ast.Node) {
+ // Maps each cancel variable to its defining ValueSpec/AssignStmt.
+ cancelvars := make(map[*types.Var]ast.Node)
+
+ // TODO(adonovan): opt: refactor to make a single pass
+ // over the AST using inspect.WithStack and node types
+ // {FuncDecl,FuncLit,CallExpr,SelectorExpr}.
+
+ // Find the set of cancel vars to analyze.
+ stack := make([]ast.Node, 0, 32)
+ ast.Inspect(node, func(n ast.Node) bool {
+ switch n.(type) {
+ case *ast.FuncLit:
+ if len(stack) > 0 {
+ return false // don't stray into nested functions
+ }
+ case nil:
+ stack = stack[:len(stack)-1] // pop
+ return true
+ }
+ stack = append(stack, n) // push
+
+ // Look for [{AssignStmt,ValueSpec} CallExpr SelectorExpr]:
+ //
+ // ctx, cancel := context.WithCancel(...)
+ // ctx, cancel = context.WithCancel(...)
+ // var ctx, cancel = context.WithCancel(...)
+ //
+ if isContextWithCancel(pass.TypesInfo, n) && isCall(stack[len(stack)-2]) {
+ var id *ast.Ident // id of cancel var
+ stmt := stack[len(stack)-3]
+ switch stmt := stmt.(type) {
+ case *ast.ValueSpec:
+ if len(stmt.Names) > 1 {
+ id = stmt.Names[1]
+ }
+ case *ast.AssignStmt:
+ if len(stmt.Lhs) > 1 {
+ id, _ = stmt.Lhs[1].(*ast.Ident)
+ }
+ }
+ if id != nil {
+ if id.Name == "_" {
+ pass.Reportf(id.Pos(),
+ "the cancel function returned by context.%s should be called, not discarded, to avoid a context leak",
+ n.(*ast.SelectorExpr).Sel.Name)
+ } else if v, ok := pass.TypesInfo.Uses[id].(*types.Var); ok {
+ cancelvars[v] = stmt
+ } else if v, ok := pass.TypesInfo.Defs[id].(*types.Var); ok {
+ cancelvars[v] = stmt
+ }
+ }
+ }
+
+ return true
+ })
+
+ if len(cancelvars) == 0 {
+ return // no need to inspect CFG
+ }
+
+ // Obtain the CFG.
+ cfgs := pass.ResultOf[ctrlflow.Analyzer].(*ctrlflow.CFGs)
+ var g *cfg.CFG
+ var sig *types.Signature
+ switch node := node.(type) {
+ case *ast.FuncDecl:
+ g = cfgs.FuncDecl(node)
+ sig, _ = pass.TypesInfo.Defs[node.Name].Type().(*types.Signature)
+ case *ast.FuncLit:
+ g = cfgs.FuncLit(node)
+ sig, _ = pass.TypesInfo.Types[node.Type].Type.(*types.Signature)
+ }
+ if sig == nil {
+ return // missing type information
+ }
+
+ // Print CFG.
+ if debug {
+ fmt.Println(g.Format(pass.Fset))
+ }
+
+ // Examine the CFG for each variable in turn.
+ // (It would be more efficient to analyze all cancelvars in a
+ // single pass over the AST, but seldom is there more than one.)
+ for v, stmt := range cancelvars {
+ if ret := lostCancelPath(pass, g, v, stmt, sig); ret != nil {
+ lineno := pass.Fset.Position(stmt.Pos()).Line
+ pass.Reportf(stmt.Pos(), "the %s function is not used on all paths (possible context leak)", v.Name())
+ pass.Reportf(ret.Pos(), "this return statement may be reached without using the %s var defined on line %d", v.Name(), lineno)
+ }
+ }
+}
+
+func isCall(n ast.Node) bool { _, ok := n.(*ast.CallExpr); return ok }
+
+func hasImport(pkg *types.Package, path string) bool {
+ for _, imp := range pkg.Imports() {
+ if imp.Path() == path {
+ return true
+ }
+ }
+ return false
+}
+
+// isContextWithCancel reports whether n is one of the qualified identifiers
+// context.With{Cancel,Timeout,Deadline}.
+func isContextWithCancel(info *types.Info, n ast.Node) bool {
+ if sel, ok := n.(*ast.SelectorExpr); ok {
+ switch sel.Sel.Name {
+ case "WithCancel", "WithTimeout", "WithDeadline":
+ if x, ok := sel.X.(*ast.Ident); ok {
+ if pkgname, ok := info.Uses[x].(*types.PkgName); ok {
+ return pkgname.Imported().Path() == contextPackage
+ }
+ // Import failed, so we can't check package path.
+ // Just check the local package name (heuristic).
+ return x.Name == "context"
+ }
+ }
+ }
+ return false
+}
+
+// lostCancelPath finds a path through the CFG, from stmt (which defines
+// the 'cancel' variable v) to a return statement, that doesn't "use" v.
+// If it finds one, it returns the return statement (which may be synthetic).
+// sig is the function's type, if known.
+func lostCancelPath(pass *analysis.Pass, g *cfg.CFG, v *types.Var, stmt ast.Node, sig *types.Signature) *ast.ReturnStmt {
+ vIsNamedResult := sig != nil && tupleContains(sig.Results(), v)
+
+ // uses reports whether stmts contain a "use" of variable v.
+ uses := func(pass *analysis.Pass, v *types.Var, stmts []ast.Node) bool {
+ found := false
+ for _, stmt := range stmts {
+ ast.Inspect(stmt, func(n ast.Node) bool {
+ switch n := n.(type) {
+ case *ast.Ident:
+ if pass.TypesInfo.Uses[n] == v {
+ found = true
+ }
+ case *ast.ReturnStmt:
+ // A naked return statement counts as a use
+ // of the named result variables.
+ if n.Results == nil && vIsNamedResult {
+ found = true
+ }
+ }
+ return !found
+ })
+ }
+ return found
+ }
+
+ // blockUses computes "uses" for each block, caching the result.
+ memo := make(map[*cfg.Block]bool)
+ blockUses := func(pass *analysis.Pass, v *types.Var, b *cfg.Block) bool {
+ res, ok := memo[b]
+ if !ok {
+ res = uses(pass, v, b.Nodes)
+ memo[b] = res
+ }
+ return res
+ }
+
+ // Find the var's defining block in the CFG,
+ // plus the rest of the statements of that block.
+ var defblock *cfg.Block
+ var rest []ast.Node
+outer:
+ for _, b := range g.Blocks {
+ for i, n := range b.Nodes {
+ if n == stmt {
+ defblock = b
+ rest = b.Nodes[i+1:]
+ break outer
+ }
+ }
+ }
+ if defblock == nil {
+ panic("internal error: can't find defining block for cancel var")
+ }
+
+ // Is v "used" in the remainder of its defining block?
+ if uses(pass, v, rest) {
+ return nil
+ }
+
+ // Does the defining block return without using v?
+ if ret := defblock.Return(); ret != nil {
+ return ret
+ }
+
+ // Search the CFG depth-first for a path, from defblock to a
+ // return block, in which v is never "used".
+ seen := make(map[*cfg.Block]bool)
+ var search func(blocks []*cfg.Block) *ast.ReturnStmt
+ search = func(blocks []*cfg.Block) *ast.ReturnStmt {
+ for _, b := range blocks {
+ if !seen[b] {
+ seen[b] = true
+
+ // Prune the search if the block uses v.
+ if blockUses(pass, v, b) {
+ continue
+ }
+
+ // Found path to return statement?
+ if ret := b.Return(); ret != nil {
+ if debug {
+ fmt.Printf("found path to return in block %s\n", b)
+ }
+ return ret // found
+ }
+
+ // Recur
+ if ret := search(b.Succs); ret != nil {
+ if debug {
+ fmt.Printf(" from block %s\n", b)
+ }
+ return ret
+ }
+ }
+ }
+ return nil
+ }
+ return search(defblock.Succs)
+}
+
+func tupleContains(tuple *types.Tuple, v *types.Var) bool {
+ for i := 0; i < tuple.Len(); i++ {
+ if tuple.At(i) == v {
+ return true
+ }
+ }
+ return false
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package nilfunc defines an Analyzer that checks for useless
+// comparisons against nil.
+package nilfunc
+
+import (
+ "go/ast"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for useless comparisons between functions and nil
+
+A useless comparison is one like f == nil as opposed to f() == nil.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "nilfunc",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.BinaryExpr)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ e := n.(*ast.BinaryExpr)
+
+ // Only want == or != comparisons.
+ if e.Op != token.EQL && e.Op != token.NEQ {
+ return
+ }
+
+ // Only want comparisons with a nil identifier on one side.
+ var e2 ast.Expr
+ switch {
+ case pass.TypesInfo.Types[e.X].IsNil():
+ e2 = e.Y
+ case pass.TypesInfo.Types[e.Y].IsNil():
+ e2 = e.X
+ default:
+ return
+ }
+
+ // Only want identifiers or selector expressions.
+ var obj types.Object
+ switch v := e2.(type) {
+ case *ast.Ident:
+ obj = pass.TypesInfo.Uses[v]
+ case *ast.SelectorExpr:
+ obj = pass.TypesInfo.Uses[v.Sel]
+ default:
+ return
+ }
+
+ // Only want functions.
+ if _, ok := obj.(*types.Func); !ok {
+ return
+ }
+
+ pass.Reportf(e.Pos(), "comparison of function %v %v nil is always %v", obj.Name(), e.Op, e.Op == token.NEQ)
+ })
+ return nil, nil
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The pkgfact package is a demonstration and test of the package fact
+// mechanism.
+//
+// The output of the pkgfact analysis is a set of key/values pairs
+// gathered from the analyzed package and its imported dependencies.
+// Each key/value pair comes from a top-level constant declaration
+// whose name starts and ends with "_". For example:
+//
+// package p
+//
+// const _greeting_ = "hello"
+// const _audience_ = "world"
+//
+// the pkgfact analysis output for package p would be:
+//
+// {"greeting": "hello", "audience": "world"}.
+//
+// In addition, the analysis reports a diagnostic at each import
+// showing which key/value pairs it contributes.
+package pkgfact
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "go/types"
+ "reflect"
+ "sort"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "pkgfact",
+ Doc: "gather name/value pairs from constant declarations",
+ Run: run,
+ FactTypes: []analysis.Fact{new(pairsFact)},
+ ResultType: reflect.TypeOf(map[string]string{}),
+}
+
+// A pairsFact is a package-level fact that records
+// an set of key=value strings accumulated from constant
+// declarations in this package and its dependencies.
+// Elements are ordered by keys, which are unique.
+type pairsFact []string
+
+func (f *pairsFact) AFact() {}
+func (f *pairsFact) String() string { return "pairs(" + strings.Join(*f, ", ") + ")" }
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ result := make(map[string]string)
+
+ // At each import, print the fact from the imported
+ // package and accumulate its information into the result.
+ // (Warning: accumulation leads to quadratic growth of work.)
+ doImport := func(spec *ast.ImportSpec) {
+ pkg := imported(pass.TypesInfo, spec)
+ var fact pairsFact
+ if pass.ImportPackageFact(pkg, &fact) {
+ for _, pair := range fact {
+ eq := strings.IndexByte(pair, '=')
+ result[pair[:eq]] = pair[1+eq:]
+ }
+ pass.Reportf(spec.Pos(), "%s", strings.Join(fact, " "))
+ }
+ }
+
+ // At each "const _name_ = value", add a fact into env.
+ doConst := func(spec *ast.ValueSpec) {
+ if len(spec.Names) == len(spec.Values) {
+ for i := range spec.Names {
+ name := spec.Names[i].Name
+ if strings.HasPrefix(name, "_") && strings.HasSuffix(name, "_") {
+
+ if key := strings.Trim(name, "_"); key != "" {
+ value := pass.TypesInfo.Types[spec.Values[i]].Value.String()
+ result[key] = value
+ }
+ }
+ }
+ }
+ }
+
+ for _, f := range pass.Files {
+ for _, decl := range f.Decls {
+ if decl, ok := decl.(*ast.GenDecl); ok {
+ for _, spec := range decl.Specs {
+ switch decl.Tok {
+ case token.IMPORT:
+ doImport(spec.(*ast.ImportSpec))
+ case token.CONST:
+ doConst(spec.(*ast.ValueSpec))
+ }
+ }
+ }
+ }
+ }
+
+ // Sort/deduplicate the result and save it as a package fact.
+ keys := make([]string, 0, len(result))
+ for key := range result {
+ keys = append(keys, key)
+ }
+ sort.Strings(keys)
+ var fact pairsFact
+ for _, key := range keys {
+ fact = append(fact, fmt.Sprintf("%s=%s", key, result[key]))
+ }
+ if len(fact) > 0 {
+ pass.ExportPackageFact(&fact)
+ }
+
+ return result, nil
+}
+
+func imported(info *types.Info, spec *ast.ImportSpec) *types.Package {
+ obj, ok := info.Implicits[spec]
+ if !ok {
+ obj = info.Defs[spec.Name] // renaming import
+ }
+ return obj.(*types.PkgName).Imported()
+}
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the printf-checker.
+
+package printf
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/constant"
+ "go/token"
+ "go/types"
+ "regexp"
+ "sort"
+ "strconv"
+ "strings"
+ "unicode/utf8"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+ "golang.org/x/tools/go/types/typeutil"
+)
+
+func init() {
+ Analyzer.Flags.Var(isPrint, "funcs", "comma-separated list of print function names to check")
+}
+
+var Analyzer = &analysis.Analyzer{
+ Name: "printf",
+ Doc: "check printf-like invocations",
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+ FactTypes: []analysis.Fact{new(isWrapper)},
+}
+
+const doc = `check consistency of Printf format strings and arguments
+
+The check applies to known functions (for example, those in package fmt)
+as well as any detected wrappers of known functions.
+
+A function that wants to avail itself of printf checking but does not
+get found by this analyzer's heuristics (for example, due to use of
+dynamic calls) can insert a bogus call:
+
+ if false {
+ fmt.Sprintf(format, args...) // enable printf checking
+ }
+
+The -funcs flag specifies a comma-separated list of names of additional
+known formatting functions or methods. If the name contains a period,
+it must denote a specific function using one of the following forms:
+
+ dir/pkg.Function
+ dir/pkg.Type.Method
+ (*dir/pkg.Type).Method
+
+Otherwise the name is interpreted as a case-insensitive unqualified
+identifier such as "errorf". Either way, if a listed name ends in f, the
+function is assumed to be Printf-like, taking a format string before the
+argument list. Otherwise it is assumed to be Print-like, taking a list
+of arguments with no format string.
+`
+
+// isWrapper is a fact indicating that a function is a print or printf wrapper.
+type isWrapper struct{ Printf bool }
+
+func (f *isWrapper) AFact() {}
+
+func (f *isWrapper) String() string {
+ if f.Printf {
+ return "printfWrapper"
+ } else {
+ return "printWrapper"
+ }
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ findPrintfLike(pass)
+ checkCall(pass)
+ return nil, nil
+}
+
+type printfWrapper struct {
+ obj *types.Func
+ fdecl *ast.FuncDecl
+ format *types.Var
+ args *types.Var
+ callers []printfCaller
+ failed bool // if true, not a printf wrapper
+}
+
+type printfCaller struct {
+ w *printfWrapper
+ call *ast.CallExpr
+}
+
+// maybePrintfWrapper decides whether decl (a declared function) may be a wrapper
+// around a fmt.Printf or fmt.Print function. If so it returns a printfWrapper
+// function describing the declaration. Later processing will analyze the
+// graph of potential printf wrappers to pick out the ones that are true wrappers.
+// A function may be a Printf or Print wrapper if its last argument is ...interface{}.
+// If the next-to-last argument is a string, then this may be a Printf wrapper.
+// Otherwise it may be a Print wrapper.
+func maybePrintfWrapper(info *types.Info, decl ast.Decl) *printfWrapper {
+ // Look for functions with final argument type ...interface{}.
+ fdecl, ok := decl.(*ast.FuncDecl)
+ if !ok || fdecl.Body == nil {
+ return nil
+ }
+ fn := info.Defs[fdecl.Name].(*types.Func)
+
+ sig := fn.Type().(*types.Signature)
+ if !sig.Variadic() {
+ return nil // not variadic
+ }
+
+ params := sig.Params()
+ nparams := params.Len() // variadic => nonzero
+
+ args := params.At(nparams - 1)
+ iface, ok := args.Type().(*types.Slice).Elem().(*types.Interface)
+ if !ok || !iface.Empty() {
+ return nil // final (args) param is not ...interface{}
+ }
+
+ // Is second last param 'format string'?
+ var format *types.Var
+ if nparams >= 2 {
+ if p := params.At(nparams - 2); p.Type() == types.Typ[types.String] {
+ format = p
+ }
+ }
+
+ return &printfWrapper{
+ obj: fn,
+ fdecl: fdecl,
+ format: format,
+ args: args,
+ }
+}
+
+// findPrintfLike scans the entire package to find printf-like functions.
+func findPrintfLike(pass *analysis.Pass) (interface{}, error) {
+ // Gather potential wrappers and call graph between them.
+ byObj := make(map[*types.Func]*printfWrapper)
+ var wrappers []*printfWrapper
+ for _, file := range pass.Files {
+ for _, decl := range file.Decls {
+ w := maybePrintfWrapper(pass.TypesInfo, decl)
+ if w == nil {
+ continue
+ }
+ byObj[w.obj] = w
+ wrappers = append(wrappers, w)
+ }
+ }
+
+ // Walk the graph to figure out which are really printf wrappers.
+ for _, w := range wrappers {
+ // Scan function for calls that could be to other printf-like functions.
+ ast.Inspect(w.fdecl.Body, func(n ast.Node) bool {
+ if w.failed {
+ return false
+ }
+
+ // TODO: Relax these checks; issue 26555.
+ if assign, ok := n.(*ast.AssignStmt); ok {
+ for _, lhs := range assign.Lhs {
+ if match(pass.TypesInfo, lhs, w.format) ||
+ match(pass.TypesInfo, lhs, w.args) {
+ // Modifies the format
+ // string or args in
+ // some way, so not a
+ // simple wrapper.
+ w.failed = true
+ return false
+ }
+ }
+ }
+ if un, ok := n.(*ast.UnaryExpr); ok && un.Op == token.AND {
+ if match(pass.TypesInfo, un.X, w.format) ||
+ match(pass.TypesInfo, un.X, w.args) {
+ // Taking the address of the
+ // format string or args,
+ // so not a simple wrapper.
+ w.failed = true
+ return false
+ }
+ }
+
+ call, ok := n.(*ast.CallExpr)
+ if !ok || len(call.Args) == 0 || !match(pass.TypesInfo, call.Args[len(call.Args)-1], w.args) {
+ return true
+ }
+
+ fn, kind := printfNameAndKind(pass, call)
+ if kind != 0 {
+ checkPrintfFwd(pass, w, call, kind)
+ return true
+ }
+
+ // If the call is to another function in this package,
+ // maybe we will find out it is printf-like later.
+ // Remember this call for later checking.
+ if fn != nil && fn.Pkg() == pass.Pkg && byObj[fn] != nil {
+ callee := byObj[fn]
+ callee.callers = append(callee.callers, printfCaller{w, call})
+ }
+
+ return true
+ })
+ }
+ return nil, nil
+}
+
+func match(info *types.Info, arg ast.Expr, param *types.Var) bool {
+ id, ok := arg.(*ast.Ident)
+ return ok && info.ObjectOf(id) == param
+}
+
+const (
+ kindPrintf = 1
+ kindPrint = 2
+)
+
+// checkPrintfFwd checks that a printf-forwarding wrapper is forwarding correctly.
+// It diagnoses writing fmt.Printf(format, args) instead of fmt.Printf(format, args...).
+func checkPrintfFwd(pass *analysis.Pass, w *printfWrapper, call *ast.CallExpr, kind int) {
+ matched := kind == kindPrint ||
+ kind == kindPrintf && len(call.Args) >= 2 && match(pass.TypesInfo, call.Args[len(call.Args)-2], w.format)
+ if !matched {
+ return
+ }
+
+ if !call.Ellipsis.IsValid() {
+ typ, ok := pass.TypesInfo.Types[call.Fun].Type.(*types.Signature)
+ if !ok {
+ return
+ }
+ if len(call.Args) > typ.Params().Len() {
+ // If we're passing more arguments than what the
+ // print/printf function can take, adding an ellipsis
+ // would break the program. For example:
+ //
+ // func foo(arg1 string, arg2 ...interface{} {
+ // fmt.Printf("%s %v", arg1, arg2)
+ // }
+ return
+ }
+ desc := "printf"
+ if kind == kindPrint {
+ desc = "print"
+ }
+ pass.Reportf(call.Pos(), "missing ... in args forwarded to %s-like function", desc)
+ return
+ }
+ fn := w.obj
+ var fact isWrapper
+ if !pass.ImportObjectFact(fn, &fact) {
+ fact.Printf = kind == kindPrintf
+ pass.ExportObjectFact(fn, &fact)
+ for _, caller := range w.callers {
+ checkPrintfFwd(pass, caller.w, caller.call, kind)
+ }
+ }
+}
+
+// isPrint records the print functions.
+// If a key ends in 'f' then it is assumed to be a formatted print.
+//
+// Keys are either values returned by (*types.Func).FullName,
+// or case-insensitive identifiers such as "errorf".
+//
+// The -funcs flag adds to this set.
+var isPrint = stringSet{
+ "fmt.Errorf": true,
+ "fmt.Fprint": true,
+ "fmt.Fprintf": true,
+ "fmt.Fprintln": true,
+ "fmt.Print": true, // technically these three
+ "fmt.Printf": true, // are redundant because they
+ "fmt.Println": true, // forward to Fprint{,f,ln}
+ "fmt.Sprint": true,
+ "fmt.Sprintf": true,
+ "fmt.Sprintln": true,
+
+ // *testing.T and B are detected by induction, but testing.TB is
+ // an interface and the inference can't follow dynamic calls.
+ "(testing.TB).Error": true,
+ "(testing.TB).Errorf": true,
+ "(testing.TB).Fatal": true,
+ "(testing.TB).Fatalf": true,
+ "(testing.TB).Log": true,
+ "(testing.TB).Logf": true,
+ "(testing.TB).Skip": true,
+ "(testing.TB).Skipf": true,
+}
+
+// formatString returns the format string argument and its index within
+// the given printf-like call expression.
+//
+// The last parameter before variadic arguments is assumed to be
+// a format string.
+//
+// The first string literal or string constant is assumed to be a format string
+// if the call's signature cannot be determined.
+//
+// If it cannot find any format string parameter, it returns ("", -1).
+func formatString(pass *analysis.Pass, call *ast.CallExpr) (format string, idx int) {
+ typ := pass.TypesInfo.Types[call.Fun].Type
+ if typ != nil {
+ if sig, ok := typ.(*types.Signature); ok {
+ if !sig.Variadic() {
+ // Skip checking non-variadic functions.
+ return "", -1
+ }
+ idx := sig.Params().Len() - 2
+ if idx < 0 {
+ // Skip checking variadic functions without
+ // fixed arguments.
+ return "", -1
+ }
+ s, ok := stringConstantArg(pass, call, idx)
+ if !ok {
+ // The last argument before variadic args isn't a string.
+ return "", -1
+ }
+ return s, idx
+ }
+ }
+
+ // Cannot determine call's signature. Fall back to scanning for the first
+ // string constant in the call.
+ for idx := range call.Args {
+ if s, ok := stringConstantArg(pass, call, idx); ok {
+ return s, idx
+ }
+ if pass.TypesInfo.Types[call.Args[idx]].Type == types.Typ[types.String] {
+ // Skip checking a call with a non-constant format
+ // string argument, since its contents are unavailable
+ // for validation.
+ return "", -1
+ }
+ }
+ return "", -1
+}
+
+// stringConstantArg returns call's string constant argument at the index idx.
+//
+// ("", false) is returned if call's argument at the index idx isn't a string
+// constant.
+func stringConstantArg(pass *analysis.Pass, call *ast.CallExpr, idx int) (string, bool) {
+ if idx >= len(call.Args) {
+ return "", false
+ }
+ arg := call.Args[idx]
+ lit := pass.TypesInfo.Types[arg].Value
+ if lit != nil && lit.Kind() == constant.String {
+ return constant.StringVal(lit), true
+ }
+ return "", false
+}
+
+// checkCall triggers the print-specific checks if the call invokes a print function.
+func checkCall(pass *analysis.Pass) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+ nodeFilter := []ast.Node{
+ (*ast.CallExpr)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ call := n.(*ast.CallExpr)
+ fn, kind := printfNameAndKind(pass, call)
+ switch kind {
+ case kindPrintf:
+ checkPrintf(pass, call, fn)
+ case kindPrint:
+ checkPrint(pass, call, fn)
+ }
+ })
+}
+
+func printfNameAndKind(pass *analysis.Pass, call *ast.CallExpr) (fn *types.Func, kind int) {
+ fn, _ = typeutil.Callee(pass.TypesInfo, call).(*types.Func)
+ if fn == nil {
+ return nil, 0
+ }
+
+ var fact isWrapper
+ if pass.ImportObjectFact(fn, &fact) {
+ if fact.Printf {
+ return fn, kindPrintf
+ } else {
+ return fn, kindPrint
+ }
+ }
+
+ _, ok := isPrint[fn.FullName()]
+ if !ok {
+ // Next look up just "printf", for use with -printf.funcs.
+ _, ok = isPrint[strings.ToLower(fn.Name())]
+ }
+ if ok {
+ if strings.HasSuffix(fn.Name(), "f") {
+ kind = kindPrintf
+ } else {
+ kind = kindPrint
+ }
+ }
+ return fn, kind
+}
+
+// isFormatter reports whether t satisfies fmt.Formatter.
+// Unlike fmt.Stringer, it's impossible to satisfy fmt.Formatter without importing fmt.
+func isFormatter(pass *analysis.Pass, t types.Type) bool {
+ for _, imp := range pass.Pkg.Imports() {
+ if imp.Path() == "fmt" {
+ formatter := imp.Scope().Lookup("Formatter").Type().Underlying().(*types.Interface)
+ return types.Implements(t, formatter)
+ }
+ }
+ return false
+}
+
+// formatState holds the parsed representation of a printf directive such as "%3.*[4]d".
+// It is constructed by parsePrintfVerb.
+type formatState struct {
+ verb rune // the format verb: 'd' for "%d"
+ format string // the full format directive from % through verb, "%.3d".
+ name string // Printf, Sprintf etc.
+ flags []byte // the list of # + etc.
+ argNums []int // the successive argument numbers that are consumed, adjusted to refer to actual arg in call
+ firstArg int // Index of first argument after the format in the Printf call.
+ // Used only during parse.
+ pass *analysis.Pass
+ call *ast.CallExpr
+ argNum int // Which argument we're expecting to format now.
+ hasIndex bool // Whether the argument is indexed.
+ indexPending bool // Whether we have an indexed argument that has not resolved.
+ nbytes int // number of bytes of the format string consumed.
+}
+
+// checkPrintf checks a call to a formatted print routine such as Printf.
+func checkPrintf(pass *analysis.Pass, call *ast.CallExpr, fn *types.Func) {
+ format, idx := formatString(pass, call)
+ if idx < 0 {
+ if false {
+ pass.Reportf(call.Lparen, "can't check non-constant format in call to %s", fn.Name())
+ }
+ return
+ }
+
+ firstArg := idx + 1 // Arguments are immediately after format string.
+ if !strings.Contains(format, "%") {
+ if len(call.Args) > firstArg {
+ pass.Reportf(call.Lparen, "%s call has arguments but no formatting directives", fn.Name())
+ }
+ return
+ }
+ // Hard part: check formats against args.
+ argNum := firstArg
+ maxArgNum := firstArg
+ anyIndex := false
+ for i, w := 0, 0; i < len(format); i += w {
+ w = 1
+ if format[i] != '%' {
+ continue
+ }
+ state := parsePrintfVerb(pass, call, fn.Name(), format[i:], firstArg, argNum)
+ if state == nil {
+ return
+ }
+ w = len(state.format)
+ if !okPrintfArg(pass, call, state) { // One error per format is enough.
+ return
+ }
+ if state.hasIndex {
+ anyIndex = true
+ }
+ if len(state.argNums) > 0 {
+ // Continue with the next sequential argument.
+ argNum = state.argNums[len(state.argNums)-1] + 1
+ }
+ for _, n := range state.argNums {
+ if n >= maxArgNum {
+ maxArgNum = n + 1
+ }
+ }
+ }
+ // Dotdotdot is hard.
+ if call.Ellipsis.IsValid() && maxArgNum >= len(call.Args)-1 {
+ return
+ }
+ // If any formats are indexed, extra arguments are ignored.
+ if anyIndex {
+ return
+ }
+ // There should be no leftover arguments.
+ if maxArgNum != len(call.Args) {
+ expect := maxArgNum - firstArg
+ numArgs := len(call.Args) - firstArg
+ pass.Reportf(call.Pos(), "%s call needs %v but has %v", fn.Name(), count(expect, "arg"), count(numArgs, "arg"))
+ }
+}
+
+// parseFlags accepts any printf flags.
+func (s *formatState) parseFlags() {
+ for s.nbytes < len(s.format) {
+ switch c := s.format[s.nbytes]; c {
+ case '#', '0', '+', '-', ' ':
+ s.flags = append(s.flags, c)
+ s.nbytes++
+ default:
+ return
+ }
+ }
+}
+
+// scanNum advances through a decimal number if present.
+func (s *formatState) scanNum() {
+ for ; s.nbytes < len(s.format); s.nbytes++ {
+ c := s.format[s.nbytes]
+ if c < '0' || '9' < c {
+ return
+ }
+ }
+}
+
+// parseIndex scans an index expression. It returns false if there is a syntax error.
+func (s *formatState) parseIndex() bool {
+ if s.nbytes == len(s.format) || s.format[s.nbytes] != '[' {
+ return true
+ }
+ // Argument index present.
+ s.nbytes++ // skip '['
+ start := s.nbytes
+ s.scanNum()
+ ok := true
+ if s.nbytes == len(s.format) || s.nbytes == start || s.format[s.nbytes] != ']' {
+ ok = false
+ s.nbytes = strings.Index(s.format, "]")
+ if s.nbytes < 0 {
+ s.pass.Reportf(s.call.Pos(), "%s format %s is missing closing ]", s.name, s.format)
+ return false
+ }
+ }
+ arg32, err := strconv.ParseInt(s.format[start:s.nbytes], 10, 32)
+ if err != nil || !ok || arg32 <= 0 || arg32 > int64(len(s.call.Args)-s.firstArg) {
+ s.pass.Reportf(s.call.Pos(), "%s format has invalid argument index [%s]", s.name, s.format[start:s.nbytes])
+ return false
+ }
+ s.nbytes++ // skip ']'
+ arg := int(arg32)
+ arg += s.firstArg - 1 // We want to zero-index the actual arguments.
+ s.argNum = arg
+ s.hasIndex = true
+ s.indexPending = true
+ return true
+}
+
+// parseNum scans a width or precision (or *). It returns false if there's a bad index expression.
+func (s *formatState) parseNum() bool {
+ if s.nbytes < len(s.format) && s.format[s.nbytes] == '*' {
+ if s.indexPending { // Absorb it.
+ s.indexPending = false
+ }
+ s.nbytes++
+ s.argNums = append(s.argNums, s.argNum)
+ s.argNum++
+ } else {
+ s.scanNum()
+ }
+ return true
+}
+
+// parsePrecision scans for a precision. It returns false if there's a bad index expression.
+func (s *formatState) parsePrecision() bool {
+ // If there's a period, there may be a precision.
+ if s.nbytes < len(s.format) && s.format[s.nbytes] == '.' {
+ s.flags = append(s.flags, '.') // Treat precision as a flag.
+ s.nbytes++
+ if !s.parseIndex() {
+ return false
+ }
+ if !s.parseNum() {
+ return false
+ }
+ }
+ return true
+}
+
+// parsePrintfVerb looks the formatting directive that begins the format string
+// and returns a formatState that encodes what the directive wants, without looking
+// at the actual arguments present in the call. The result is nil if there is an error.
+func parsePrintfVerb(pass *analysis.Pass, call *ast.CallExpr, name, format string, firstArg, argNum int) *formatState {
+ state := &formatState{
+ format: format,
+ name: name,
+ flags: make([]byte, 0, 5),
+ argNum: argNum,
+ argNums: make([]int, 0, 1),
+ nbytes: 1, // There's guaranteed to be a percent sign.
+ firstArg: firstArg,
+ pass: pass,
+ call: call,
+ }
+ // There may be flags.
+ state.parseFlags()
+ // There may be an index.
+ if !state.parseIndex() {
+ return nil
+ }
+ // There may be a width.
+ if !state.parseNum() {
+ return nil
+ }
+ // There may be a precision.
+ if !state.parsePrecision() {
+ return nil
+ }
+ // Now a verb, possibly prefixed by an index (which we may already have).
+ if !state.indexPending && !state.parseIndex() {
+ return nil
+ }
+ if state.nbytes == len(state.format) {
+ pass.Reportf(call.Pos(), "%s format %s is missing verb at end of string", name, state.format)
+ return nil
+ }
+ verb, w := utf8.DecodeRuneInString(state.format[state.nbytes:])
+ state.verb = verb
+ state.nbytes += w
+ if verb != '%' {
+ state.argNums = append(state.argNums, state.argNum)
+ }
+ state.format = state.format[:state.nbytes]
+ return state
+}
+
+// printfArgType encodes the types of expressions a printf verb accepts. It is a bitmask.
+type printfArgType int
+
+const (
+ argBool printfArgType = 1 << iota
+ argInt
+ argRune
+ argString
+ argFloat
+ argComplex
+ argPointer
+ anyType printfArgType = ^0
+)
+
+type printVerb struct {
+ verb rune // User may provide verb through Formatter; could be a rune.
+ flags string // known flags are all ASCII
+ typ printfArgType
+}
+
+// Common flag sets for printf verbs.
+const (
+ noFlag = ""
+ numFlag = " -+.0"
+ sharpNumFlag = " -+.0#"
+ allFlags = " -+.0#"
+)
+
+// printVerbs identifies which flags are known to printf for each verb.
+var printVerbs = []printVerb{
+ // '-' is a width modifier, always valid.
+ // '.' is a precision for float, max width for strings.
+ // '+' is required sign for numbers, Go format for %v.
+ // '#' is alternate format for several verbs.
+ // ' ' is spacer for numbers
+ {'%', noFlag, 0},
+ {'b', numFlag, argInt | argFloat | argComplex},
+ {'c', "-", argRune | argInt},
+ {'d', numFlag, argInt | argPointer},
+ {'e', sharpNumFlag, argFloat | argComplex},
+ {'E', sharpNumFlag, argFloat | argComplex},
+ {'f', sharpNumFlag, argFloat | argComplex},
+ {'F', sharpNumFlag, argFloat | argComplex},
+ {'g', sharpNumFlag, argFloat | argComplex},
+ {'G', sharpNumFlag, argFloat | argComplex},
+ {'o', sharpNumFlag, argInt},
+ {'p', "-#", argPointer},
+ {'q', " -+.0#", argRune | argInt | argString},
+ {'s', " -+.0", argString},
+ {'t', "-", argBool},
+ {'T', "-", anyType},
+ {'U', "-#", argRune | argInt},
+ {'v', allFlags, anyType},
+ {'x', sharpNumFlag, argRune | argInt | argString | argPointer},
+ {'X', sharpNumFlag, argRune | argInt | argString | argPointer},
+}
+
+// okPrintfArg compares the formatState to the arguments actually present,
+// reporting any discrepancies it can discern. If the final argument is ellipsissed,
+// there's little it can do for that.
+func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, state *formatState) (ok bool) {
+ var v printVerb
+ found := false
+ // Linear scan is fast enough for a small list.
+ for _, v = range printVerbs {
+ if v.verb == state.verb {
+ found = true
+ break
+ }
+ }
+
+ // Does current arg implement fmt.Formatter?
+ formatter := false
+ if state.argNum < len(call.Args) {
+ if tv, ok := pass.TypesInfo.Types[call.Args[state.argNum]]; ok {
+ formatter = isFormatter(pass, tv.Type)
+ }
+ }
+
+ if !formatter {
+ if !found {
+ pass.Reportf(call.Pos(), "%s format %s has unknown verb %c", state.name, state.format, state.verb)
+ return false
+ }
+ for _, flag := range state.flags {
+ // TODO: Disable complaint about '0' for Go 1.10. To be fixed properly in 1.11.
+ // See issues 23598 and 23605.
+ if flag == '0' {
+ continue
+ }
+ if !strings.ContainsRune(v.flags, rune(flag)) {
+ pass.Reportf(call.Pos(), "%s format %s has unrecognized flag %c", state.name, state.format, flag)
+ return false
+ }
+ }
+ }
+ // Verb is good. If len(state.argNums)>trueArgs, we have something like %.*s and all
+ // but the final arg must be an integer.
+ trueArgs := 1
+ if state.verb == '%' {
+ trueArgs = 0
+ }
+ nargs := len(state.argNums)
+ for i := 0; i < nargs-trueArgs; i++ {
+ argNum := state.argNums[i]
+ if !argCanBeChecked(pass, call, i, state) {
+ return
+ }
+ arg := call.Args[argNum]
+ if !matchArgType(pass, argInt, nil, arg) {
+ pass.Reportf(call.Pos(), "%s format %s uses non-int %s as argument of *", state.name, state.format, analysisutil.Format(pass.Fset, arg))
+ return false
+ }
+ }
+
+ if state.verb == '%' || formatter {
+ return true
+ }
+ argNum := state.argNums[len(state.argNums)-1]
+ if !argCanBeChecked(pass, call, len(state.argNums)-1, state) {
+ return false
+ }
+ arg := call.Args[argNum]
+ if isFunctionValue(pass, arg) && state.verb != 'p' && state.verb != 'T' {
+ pass.Reportf(call.Pos(), "%s format %s arg %s is a func value, not called", state.name, state.format, analysisutil.Format(pass.Fset, arg))
+ return false
+ }
+ if !matchArgType(pass, v.typ, nil, arg) {
+ typeString := ""
+ if typ := pass.TypesInfo.Types[arg].Type; typ != nil {
+ typeString = typ.String()
+ }
+ pass.Reportf(call.Pos(), "%s format %s has arg %s of wrong type %s", state.name, state.format, analysisutil.Format(pass.Fset, arg), typeString)
+ return false
+ }
+ if v.typ&argString != 0 && v.verb != 'T' && !bytes.Contains(state.flags, []byte{'#'}) && recursiveStringer(pass, arg) {
+ pass.Reportf(call.Pos(), "%s format %s with arg %s causes recursive String method call", state.name, state.format, analysisutil.Format(pass.Fset, arg))
+ return false
+ }
+ return true
+}
+
+// recursiveStringer reports whether the argument e is a potential
+// recursive call to stringer, such as t and &t in these examples:
+//
+// func (t *T) String() string { printf("%s", t) }
+// func (t T) String() string { printf("%s", t) }
+// func (t T) String() string { printf("%s", &t) }
+//
+func recursiveStringer(pass *analysis.Pass, e ast.Expr) bool {
+ typ := pass.TypesInfo.Types[e].Type
+
+ // It's unlikely to be a recursive stringer if it has a Format method.
+ if isFormatter(pass, typ) {
+ return false
+ }
+
+ // Does e allow e.String()?
+ obj, _, _ := types.LookupFieldOrMethod(typ, false, pass.Pkg, "String")
+ stringMethod, ok := obj.(*types.Func)
+ if !ok {
+ return false
+ }
+
+ // Is the expression e within the body of that String method?
+ return stringMethod.Pkg() == pass.Pkg && stringMethod.Scope().Contains(e.Pos())
+}
+
+// isFunctionValue reports whether the expression is a function as opposed to a function call.
+// It is almost always a mistake to print a function value.
+func isFunctionValue(pass *analysis.Pass, e ast.Expr) bool {
+ if typ := pass.TypesInfo.Types[e].Type; typ != nil {
+ _, ok := typ.(*types.Signature)
+ return ok
+ }
+ return false
+}
+
+// argCanBeChecked reports whether the specified argument is statically present;
+// it may be beyond the list of arguments or in a terminal slice... argument, which
+// means we can't see it.
+func argCanBeChecked(pass *analysis.Pass, call *ast.CallExpr, formatArg int, state *formatState) bool {
+ argNum := state.argNums[formatArg]
+ if argNum <= 0 {
+ // Shouldn't happen, so catch it with prejudice.
+ panic("negative arg num")
+ }
+ if argNum < len(call.Args)-1 {
+ return true // Always OK.
+ }
+ if call.Ellipsis.IsValid() {
+ return false // We just can't tell; there could be many more arguments.
+ }
+ if argNum < len(call.Args) {
+ return true
+ }
+ // There are bad indexes in the format or there are fewer arguments than the format needs.
+ // This is the argument number relative to the format: Printf("%s", "hi") will give 1 for the "hi".
+ arg := argNum - state.firstArg + 1 // People think of arguments as 1-indexed.
+ pass.Reportf(call.Pos(), "%s format %s reads arg #%d, but call has %v", state.name, state.format, arg, count(len(call.Args)-state.firstArg, "arg"))
+ return false
+}
+
+// printFormatRE is the regexp we match and report as a possible format string
+// in the first argument to unformatted prints like fmt.Print.
+// We exclude the space flag, so that printing a string like "x % y" is not reported as a format.
+var printFormatRE = regexp.MustCompile(`%` + flagsRE + numOptRE + `\.?` + numOptRE + indexOptRE + verbRE)
+
+const (
+ flagsRE = `[+\-#]*`
+ indexOptRE = `(\[[0-9]+\])?`
+ numOptRE = `([0-9]+|` + indexOptRE + `\*)?`
+ verbRE = `[bcdefgopqstvxEFGTUX]`
+)
+
+// checkPrint checks a call to an unformatted print routine such as Println.
+func checkPrint(pass *analysis.Pass, call *ast.CallExpr, fn *types.Func) {
+ firstArg := 0
+ typ := pass.TypesInfo.Types[call.Fun].Type
+ if typ == nil {
+ // Skip checking functions with unknown type.
+ return
+ }
+ if sig, ok := typ.(*types.Signature); ok {
+ if !sig.Variadic() {
+ // Skip checking non-variadic functions.
+ return
+ }
+ params := sig.Params()
+ firstArg = params.Len() - 1
+
+ typ := params.At(firstArg).Type()
+ typ = typ.(*types.Slice).Elem()
+ it, ok := typ.(*types.Interface)
+ if !ok || !it.Empty() {
+ // Skip variadic functions accepting non-interface{} args.
+ return
+ }
+ }
+ args := call.Args
+ if len(args) <= firstArg {
+ // Skip calls without variadic args.
+ return
+ }
+ args = args[firstArg:]
+
+ if firstArg == 0 {
+ if sel, ok := call.Args[0].(*ast.SelectorExpr); ok {
+ if x, ok := sel.X.(*ast.Ident); ok {
+ if x.Name == "os" && strings.HasPrefix(sel.Sel.Name, "Std") {
+ pass.Reportf(call.Pos(), "%s does not take io.Writer but has first arg %s", fn.Name(), analysisutil.Format(pass.Fset, call.Args[0]))
+ }
+ }
+ }
+ }
+
+ arg := args[0]
+ if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
+ // Ignore trailing % character in lit.Value.
+ // The % in "abc 0.0%" couldn't be a formatting directive.
+ s := strings.TrimSuffix(lit.Value, `%"`)
+ if strings.Contains(s, "%") {
+ m := printFormatRE.FindStringSubmatch(s)
+ if m != nil {
+ pass.Reportf(call.Pos(), "%s call has possible formatting directive %s", fn.Name(), m[0])
+ }
+ }
+ }
+ if strings.HasSuffix(fn.Name(), "ln") {
+ // The last item, if a string, should not have a newline.
+ arg = args[len(args)-1]
+ if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
+ str, _ := strconv.Unquote(lit.Value)
+ if strings.HasSuffix(str, "\n") {
+ pass.Reportf(call.Pos(), "%s arg list ends with redundant newline", fn.Name())
+ }
+ }
+ }
+ for _, arg := range args {
+ if isFunctionValue(pass, arg) {
+ pass.Reportf(call.Pos(), "%s arg %s is a func value, not called", fn.Name(), analysisutil.Format(pass.Fset, arg))
+ }
+ if recursiveStringer(pass, arg) {
+ pass.Reportf(call.Pos(), "%s arg %s causes recursive call to String method", fn.Name(), analysisutil.Format(pass.Fset, arg))
+ }
+ }
+}
+
+// count(n, what) returns "1 what" or "N whats"
+// (assuming the plural of what is whats).
+func count(n int, what string) string {
+ if n == 1 {
+ return "1 " + what
+ }
+ return fmt.Sprintf("%d %ss", n, what)
+}
+
+// stringSet is a set-of-nonempty-strings-valued flag.
+// Note: elements without a '.' get lower-cased.
+type stringSet map[string]bool
+
+func (ss stringSet) String() string {
+ var list []string
+ for name := range ss {
+ list = append(list, name)
+ }
+ sort.Strings(list)
+ return strings.Join(list, ",")
+}
+
+func (ss stringSet) Set(flag string) error {
+ for _, name := range strings.Split(flag, ",") {
+ if len(name) == 0 {
+ return fmt.Errorf("empty string")
+ }
+ if !strings.Contains(name, ".") {
+ name = strings.ToLower(name)
+ }
+ ss[name] = true
+ }
+ return nil
+}
--- /dev/null
+package printf
+
+import (
+ "go/ast"
+ "go/build"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+)
+
+var errorType = types.Universe.Lookup("error").Type().Underlying().(*types.Interface)
+
+// matchArgType reports an error if printf verb t is not appropriate
+// for operand arg.
+//
+// typ is used only for recursive calls; external callers must supply nil.
+//
+// (Recursion arises from the compound types {map,chan,slice} which
+// may be printed with %d etc. if that is appropriate for their element
+// types.)
+func matchArgType(pass *analysis.Pass, t printfArgType, typ types.Type, arg ast.Expr) bool {
+ return matchArgTypeInternal(pass, t, typ, arg, make(map[types.Type]bool))
+}
+
+// matchArgTypeInternal is the internal version of matchArgType. It carries a map
+// remembering what types are in progress so we don't recur when faced with recursive
+// types or mutually recursive types.
+func matchArgTypeInternal(pass *analysis.Pass, t printfArgType, typ types.Type, arg ast.Expr, inProgress map[types.Type]bool) bool {
+ // %v, %T accept any argument type.
+ if t == anyType {
+ return true
+ }
+ if typ == nil {
+ // external call
+ typ = pass.TypesInfo.Types[arg].Type
+ if typ == nil {
+ return true // probably a type check problem
+ }
+ }
+ // If the type implements fmt.Formatter, we have nothing to check.
+ if isFormatter(pass, typ) {
+ return true
+ }
+ // If we can use a string, might arg (dynamically) implement the Stringer or Error interface?
+ if t&argString != 0 && isConvertibleToString(pass, typ) {
+ return true
+ }
+
+ typ = typ.Underlying()
+ if inProgress[typ] {
+ // We're already looking at this type. The call that started it will take care of it.
+ return true
+ }
+ inProgress[typ] = true
+
+ switch typ := typ.(type) {
+ case *types.Signature:
+ return t&argPointer != 0
+
+ case *types.Map:
+ // Recur: map[int]int matches %d.
+ return t&argPointer != 0 ||
+ (matchArgTypeInternal(pass, t, typ.Key(), arg, inProgress) && matchArgTypeInternal(pass, t, typ.Elem(), arg, inProgress))
+
+ case *types.Chan:
+ return t&argPointer != 0
+
+ case *types.Array:
+ // Same as slice.
+ if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
+ return true // %s matches []byte
+ }
+ // Recur: []int matches %d.
+ return t&argPointer != 0 || matchArgTypeInternal(pass, t, typ.Elem(), arg, inProgress)
+
+ case *types.Slice:
+ // Same as array.
+ if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
+ return true // %s matches []byte
+ }
+ // Recur: []int matches %d. But watch out for
+ // type T []T
+ // If the element is a pointer type (type T[]*T), it's handled fine by the Pointer case below.
+ return t&argPointer != 0 || matchArgTypeInternal(pass, t, typ.Elem(), arg, inProgress)
+
+ case *types.Pointer:
+ // Ugly, but dealing with an edge case: a known pointer to an invalid type,
+ // probably something from a failed import.
+ if typ.Elem().String() == "invalid type" {
+ if false {
+ pass.Reportf(arg.Pos(), "printf argument %v is pointer to invalid or unknown type", analysisutil.Format(pass.Fset, arg))
+ }
+ return true // special case
+ }
+ // If it's actually a pointer with %p, it prints as one.
+ if t == argPointer {
+ return true
+ }
+ // If it's pointer to struct, that's equivalent in our analysis to whether we can print the struct.
+ if str, ok := typ.Elem().Underlying().(*types.Struct); ok {
+ return matchStructArgType(pass, t, str, arg, inProgress)
+ }
+ // Check whether the rest can print pointers.
+ return t&argPointer != 0
+
+ case *types.Struct:
+ return matchStructArgType(pass, t, typ, arg, inProgress)
+
+ case *types.Interface:
+ // There's little we can do.
+ // Whether any particular verb is valid depends on the argument.
+ // The user may have reasonable prior knowledge of the contents of the interface.
+ return true
+
+ case *types.Basic:
+ switch typ.Kind() {
+ case types.UntypedBool,
+ types.Bool:
+ return t&argBool != 0
+
+ case types.UntypedInt,
+ types.Int,
+ types.Int8,
+ types.Int16,
+ types.Int32,
+ types.Int64,
+ types.Uint,
+ types.Uint8,
+ types.Uint16,
+ types.Uint32,
+ types.Uint64,
+ types.Uintptr:
+ return t&argInt != 0
+
+ case types.UntypedFloat,
+ types.Float32,
+ types.Float64:
+ return t&argFloat != 0
+
+ case types.UntypedComplex,
+ types.Complex64,
+ types.Complex128:
+ return t&argComplex != 0
+
+ case types.UntypedString,
+ types.String:
+ return t&argString != 0
+
+ case types.UnsafePointer:
+ return t&(argPointer|argInt) != 0
+
+ case types.UntypedRune:
+ return t&(argInt|argRune) != 0
+
+ case types.UntypedNil:
+ return false
+
+ case types.Invalid:
+ if false {
+ pass.Reportf(arg.Pos(), "printf argument %v has invalid or unknown type", analysisutil.Format(pass.Fset, arg))
+ }
+ return true // Probably a type check problem.
+ }
+ panic("unreachable")
+ }
+
+ return false
+}
+
+func isConvertibleToString(pass *analysis.Pass, typ types.Type) bool {
+ if bt, ok := typ.(*types.Basic); ok && bt.Kind() == types.UntypedNil {
+ // We explicitly don't want untyped nil, which is
+ // convertible to both of the interfaces below, as it
+ // would just panic anyway.
+ return false
+ }
+ if types.ConvertibleTo(typ, errorType) {
+ return true // via .Error()
+ }
+
+ // Does it implement fmt.Stringer?
+ if obj, _, _ := types.LookupFieldOrMethod(typ, false, nil, "String"); obj != nil {
+ if fn, ok := obj.(*types.Func); ok {
+ sig := fn.Type().(*types.Signature)
+ if sig.Params().Len() == 0 &&
+ sig.Results().Len() == 1 &&
+ sig.Results().At(0).Type() == types.Typ[types.String] {
+ return true
+ }
+ }
+ }
+
+ return false
+}
+
+// hasBasicType reports whether x's type is a types.Basic with the given kind.
+func hasBasicType(pass *analysis.Pass, x ast.Expr, kind types.BasicKind) bool {
+ t := pass.TypesInfo.Types[x].Type
+ if t != nil {
+ t = t.Underlying()
+ }
+ b, ok := t.(*types.Basic)
+ return ok && b.Kind() == kind
+}
+
+// matchStructArgType reports whether all the elements of the struct match the expected
+// type. For instance, with "%d" all the elements must be printable with the "%d" format.
+func matchStructArgType(pass *analysis.Pass, t printfArgType, typ *types.Struct, arg ast.Expr, inProgress map[types.Type]bool) bool {
+ for i := 0; i < typ.NumFields(); i++ {
+ typf := typ.Field(i)
+ if !matchArgTypeInternal(pass, t, typf.Type(), arg, inProgress) {
+ return false
+ }
+ if t&argString != 0 && !typf.Exported() && isConvertibleToString(pass, typf.Type()) {
+ // Issue #17798: unexported Stringer or error cannot be properly fomatted.
+ return false
+ }
+ }
+ return true
+}
+
+var archSizes = types.SizesFor("gc", build.Default.GOARCH)
--- /dev/null
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package shift
+
+// Simplified dead code detector.
+// Used for skipping shift checks on unreachable arch-specific code.
+
+import (
+ "go/ast"
+ "go/constant"
+ "go/types"
+)
+
+// updateDead puts unreachable "if" and "case" nodes into dead.
+func updateDead(info *types.Info, dead map[ast.Node]bool, node ast.Node) {
+ if dead[node] {
+ // The node is already marked as dead.
+ return
+ }
+
+ // setDead marks the node and all the children as dead.
+ setDead := func(n ast.Node) {
+ ast.Inspect(n, func(node ast.Node) bool {
+ if node != nil {
+ dead[node] = true
+ }
+ return true
+ })
+ }
+
+ switch stmt := node.(type) {
+ case *ast.IfStmt:
+ // "if" branch is dead if its condition evaluates
+ // to constant false.
+ v := info.Types[stmt.Cond].Value
+ if v == nil {
+ return
+ }
+ if !constant.BoolVal(v) {
+ setDead(stmt.Body)
+ return
+ }
+ if stmt.Else != nil {
+ setDead(stmt.Else)
+ }
+ case *ast.SwitchStmt:
+ // Case clause with empty switch tag is dead if it evaluates
+ // to constant false.
+ if stmt.Tag == nil {
+ BodyLoopBool:
+ for _, stmt := range stmt.Body.List {
+ cc := stmt.(*ast.CaseClause)
+ if cc.List == nil {
+ // Skip default case.
+ continue
+ }
+ for _, expr := range cc.List {
+ v := info.Types[expr].Value
+ if v == nil || v.Kind() != constant.Bool || constant.BoolVal(v) {
+ continue BodyLoopBool
+ }
+ }
+ setDead(cc)
+ }
+ return
+ }
+
+ // Case clause is dead if its constant value doesn't match
+ // the constant value from the switch tag.
+ // TODO: This handles integer comparisons only.
+ v := info.Types[stmt.Tag].Value
+ if v == nil || v.Kind() != constant.Int {
+ return
+ }
+ tagN, ok := constant.Uint64Val(v)
+ if !ok {
+ return
+ }
+ BodyLoopInt:
+ for _, x := range stmt.Body.List {
+ cc := x.(*ast.CaseClause)
+ if cc.List == nil {
+ // Skip default case.
+ continue
+ }
+ for _, expr := range cc.List {
+ v := info.Types[expr].Value
+ if v == nil {
+ continue BodyLoopInt
+ }
+ n, ok := constant.Uint64Val(v)
+ if !ok || tagN == n {
+ continue BodyLoopInt
+ }
+ }
+ setDead(cc)
+ }
+ }
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package shift defines an Analyzer that checks for shifts that exceed
+// the width of an integer.
+package shift
+
+// TODO(adonovan): integrate with ctrflow (CFG-based) dead code analysis. May
+// have impedance mismatch due to its (non-)treatment of constant
+// expressions (such as runtime.GOARCH=="386").
+
+import (
+ "go/ast"
+ "go/build"
+ "go/constant"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+var Analyzer = &analysis.Analyzer{
+ Name: "shift",
+ Doc: "check for shifts that equal or exceed the width of the integer",
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ // Do a complete pass to compute dead nodes.
+ dead := make(map[ast.Node]bool)
+ nodeFilter := []ast.Node{
+ (*ast.IfStmt)(nil),
+ (*ast.SwitchStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ // TODO(adonovan): move updateDead into this file.
+ updateDead(pass.TypesInfo, dead, n)
+ })
+
+ nodeFilter = []ast.Node{
+ (*ast.AssignStmt)(nil),
+ (*ast.BinaryExpr)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(node ast.Node) {
+ if dead[node] {
+ // Skip shift checks on unreachable nodes.
+ return
+ }
+
+ switch node := node.(type) {
+ case *ast.BinaryExpr:
+ if node.Op == token.SHL || node.Op == token.SHR {
+ checkLongShift(pass, node, node.X, node.Y)
+ }
+ case *ast.AssignStmt:
+ if len(node.Lhs) != 1 || len(node.Rhs) != 1 {
+ return
+ }
+ if node.Tok == token.SHL_ASSIGN || node.Tok == token.SHR_ASSIGN {
+ checkLongShift(pass, node, node.Lhs[0], node.Rhs[0])
+ }
+ }
+ })
+ return nil, nil
+}
+
+// checkLongShift checks if shift or shift-assign operations shift by more than
+// the length of the underlying variable.
+func checkLongShift(pass *analysis.Pass, node ast.Node, x, y ast.Expr) {
+ if pass.TypesInfo.Types[x].Value != nil {
+ // Ignore shifts of constants.
+ // These are frequently used for bit-twiddling tricks
+ // like ^uint(0) >> 63 for 32/64 bit detection and compatibility.
+ return
+ }
+
+ v := pass.TypesInfo.Types[y].Value
+ if v == nil {
+ return
+ }
+ amt, ok := constant.Int64Val(v)
+ if !ok {
+ return
+ }
+ t := pass.TypesInfo.Types[x].Type
+ if t == nil {
+ return
+ }
+ b, ok := t.Underlying().(*types.Basic)
+ if !ok {
+ return
+ }
+ var size int64
+ switch b.Kind() {
+ case types.Uint8, types.Int8:
+ size = 8
+ case types.Uint16, types.Int16:
+ size = 16
+ case types.Uint32, types.Int32:
+ size = 32
+ case types.Uint64, types.Int64:
+ size = 64
+ case types.Int, types.Uint:
+ size = uintBitSize
+ case types.Uintptr:
+ size = uintptrBitSize
+ default:
+ return
+ }
+ if amt >= size {
+ ident := analysisutil.Format(pass.Fset, x)
+ pass.Reportf(node.Pos(), "%s (%d bits) too small for shift of %d", ident, size, amt)
+ }
+}
+
+var (
+ uintBitSize = 8 * archSizes.Sizeof(types.Typ[types.Uint])
+ uintptrBitSize = 8 * archSizes.Sizeof(types.Typ[types.Uintptr])
+)
+
+var archSizes = types.SizesFor("gc", build.Default.GOARCH)
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package stdmethods defines an Analyzer that checks for misspellings
+// in the signatures of methods similar to well-known interfaces.
+package stdmethods
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/printer"
+ "go/token"
+ "go/types"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check signature of methods of well-known interfaces
+
+Sometimes a type may be intended to satisfy an interface but may fail to
+do so because of a mistake in its method signature.
+For example, the result of this WriteTo method should be (int64, error),
+not error, to satisfy io.WriterTo:
+
+ type myWriterTo struct{...}
+ func (myWriterTo) WriteTo(w io.Writer) error { ... }
+
+This check ensures that each method whose name matches one of several
+well-known interface methods from the standard library has the correct
+signature for that interface.
+
+Checked method names include:
+ Format GobEncode GobDecode MarshalJSON MarshalXML
+ Peek ReadByte ReadFrom ReadRune Scan Seek
+ UnmarshalJSON UnreadByte UnreadRune WriteByte
+ WriteTo
+`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "stdmethods",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+// canonicalMethods lists the input and output types for Go methods
+// that are checked using dynamic interface checks. Because the
+// checks are dynamic, such methods would not cause a compile error
+// if they have the wrong signature: instead the dynamic check would
+// fail, sometimes mysteriously. If a method is found with a name listed
+// here but not the input/output types listed here, vet complains.
+//
+// A few of the canonical methods have very common names.
+// For example, a type might implement a Scan method that
+// has nothing to do with fmt.Scanner, but we still want to check
+// the methods that are intended to implement fmt.Scanner.
+// To do that, the arguments that have a = prefix are treated as
+// signals that the canonical meaning is intended: if a Scan
+// method doesn't have a fmt.ScanState as its first argument,
+// we let it go. But if it does have a fmt.ScanState, then the
+// rest has to match.
+var canonicalMethods = map[string]struct{ args, results []string }{
+ // "Flush": {{}, {"error"}}, // http.Flusher and jpeg.writer conflict
+ "Format": {[]string{"=fmt.State", "rune"}, []string{}}, // fmt.Formatter
+ "GobDecode": {[]string{"[]byte"}, []string{"error"}}, // gob.GobDecoder
+ "GobEncode": {[]string{}, []string{"[]byte", "error"}}, // gob.GobEncoder
+ "MarshalJSON": {[]string{}, []string{"[]byte", "error"}}, // json.Marshaler
+ "MarshalXML": {[]string{"*xml.Encoder", "xml.StartElement"}, []string{"error"}}, // xml.Marshaler
+ "ReadByte": {[]string{}, []string{"byte", "error"}}, // io.ByteReader
+ "ReadFrom": {[]string{"=io.Reader"}, []string{"int64", "error"}}, // io.ReaderFrom
+ "ReadRune": {[]string{}, []string{"rune", "int", "error"}}, // io.RuneReader
+ "Scan": {[]string{"=fmt.ScanState", "rune"}, []string{"error"}}, // fmt.Scanner
+ "Seek": {[]string{"=int64", "int"}, []string{"int64", "error"}}, // io.Seeker
+ "UnmarshalJSON": {[]string{"[]byte"}, []string{"error"}}, // json.Unmarshaler
+ "UnmarshalXML": {[]string{"*xml.Decoder", "xml.StartElement"}, []string{"error"}}, // xml.Unmarshaler
+ "UnreadByte": {[]string{}, []string{"error"}},
+ "UnreadRune": {[]string{}, []string{"error"}},
+ "WriteByte": {[]string{"byte"}, []string{"error"}}, // jpeg.writer (matching bufio.Writer)
+ "WriteTo": {[]string{"=io.Writer"}, []string{"int64", "error"}}, // io.WriterTo
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.FuncDecl)(nil),
+ (*ast.InterfaceType)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ switch n := n.(type) {
+ case *ast.FuncDecl:
+ if n.Recv != nil {
+ canonicalMethod(pass, n.Name, n.Type)
+ }
+ case *ast.InterfaceType:
+ for _, field := range n.Methods.List {
+ for _, id := range field.Names {
+ canonicalMethod(pass, id, field.Type.(*ast.FuncType))
+ }
+ }
+ }
+ })
+ return nil, nil
+}
+
+func canonicalMethod(pass *analysis.Pass, id *ast.Ident, t *ast.FuncType) {
+ // Expected input/output.
+ expect, ok := canonicalMethods[id.Name]
+ if !ok {
+ return
+ }
+
+ // Actual input/output
+ args := typeFlatten(t.Params.List)
+ var results []ast.Expr
+ if t.Results != nil {
+ results = typeFlatten(t.Results.List)
+ }
+
+ // Do the =s (if any) all match?
+ if !matchParams(pass, expect.args, args, "=") || !matchParams(pass, expect.results, results, "=") {
+ return
+ }
+
+ // Everything must match.
+ if !matchParams(pass, expect.args, args, "") || !matchParams(pass, expect.results, results, "") {
+ expectFmt := id.Name + "(" + argjoin(expect.args) + ")"
+ if len(expect.results) == 1 {
+ expectFmt += " " + argjoin(expect.results)
+ } else if len(expect.results) > 1 {
+ expectFmt += " (" + argjoin(expect.results) + ")"
+ }
+
+ var buf bytes.Buffer
+ if err := printer.Fprint(&buf, pass.Fset, t); err != nil {
+ fmt.Fprintf(&buf, "<%s>", err)
+ }
+ actual := buf.String()
+ actual = strings.TrimPrefix(actual, "func")
+ actual = id.Name + actual
+
+ pass.Reportf(id.Pos(), "method %s should have signature %s", actual, expectFmt)
+ }
+}
+
+func argjoin(x []string) string {
+ y := make([]string, len(x))
+ for i, s := range x {
+ if s[0] == '=' {
+ s = s[1:]
+ }
+ y[i] = s
+ }
+ return strings.Join(y, ", ")
+}
+
+// Turn parameter list into slice of types
+// (in the ast, types are Exprs).
+// Have to handle f(int, bool) and f(x, y, z int)
+// so not a simple 1-to-1 conversion.
+func typeFlatten(l []*ast.Field) []ast.Expr {
+ var t []ast.Expr
+ for _, f := range l {
+ if len(f.Names) == 0 {
+ t = append(t, f.Type)
+ continue
+ }
+ for range f.Names {
+ t = append(t, f.Type)
+ }
+ }
+ return t
+}
+
+// Does each type in expect with the given prefix match the corresponding type in actual?
+func matchParams(pass *analysis.Pass, expect []string, actual []ast.Expr, prefix string) bool {
+ for i, x := range expect {
+ if !strings.HasPrefix(x, prefix) {
+ continue
+ }
+ if i >= len(actual) {
+ return false
+ }
+ if !matchParamType(pass.Fset, pass.Pkg, x, actual[i]) {
+ return false
+ }
+ }
+ if prefix == "" && len(actual) > len(expect) {
+ return false
+ }
+ return true
+}
+
+// Does this one type match?
+func matchParamType(fset *token.FileSet, pkg *types.Package, expect string, actual ast.Expr) bool {
+ expect = strings.TrimPrefix(expect, "=")
+ // Strip package name if we're in that package.
+ if n := len(pkg.Name()); len(expect) > n && expect[:n] == pkg.Name() && expect[n] == '.' {
+ expect = expect[n+1:]
+ }
+
+ // Overkill but easy.
+ var buf bytes.Buffer
+ printer.Fprint(&buf, fset, actual)
+ return buf.String() == expect
+}
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package structtag defines an Analyzer that checks struct field tags
+// are well formed.
+package structtag
+
+import (
+ "errors"
+ "go/ast"
+ "go/token"
+ "go/types"
+ "path/filepath"
+ "reflect"
+ "strconv"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check that struct field tags conform to reflect.StructTag.Get
+
+Also report certain struct tags (json, xml) used with unexported fields.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "structtag",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.StructType)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ styp := pass.TypesInfo.Types[n.(*ast.StructType)].Type.(*types.Struct)
+ var seen map[[2]string]token.Pos
+ for i := 0; i < styp.NumFields(); i++ {
+ field := styp.Field(i)
+ tag := styp.Tag(i)
+ checkCanonicalFieldTag(pass, field, tag, &seen)
+ }
+ })
+ return nil, nil
+}
+
+var checkTagDups = []string{"json", "xml"}
+var checkTagSpaces = map[string]bool{"json": true, "xml": true, "asn1": true}
+
+// checkCanonicalFieldTag checks a single struct field tag.
+func checkCanonicalFieldTag(pass *analysis.Pass, field *types.Var, tag string, seen *map[[2]string]token.Pos) {
+ for _, key := range checkTagDups {
+ checkTagDuplicates(pass, tag, key, field, field, seen)
+ }
+
+ if err := validateStructTag(tag); err != nil {
+ pass.Reportf(field.Pos(), "struct field tag %#q not compatible with reflect.StructTag.Get: %s", tag, err)
+ }
+
+ // Check for use of json or xml tags with unexported fields.
+
+ // Embedded struct. Nothing to do for now, but that
+ // may change, depending on what happens with issue 7363.
+ // TODO(adonovan): investigate, now that that issue is fixed.
+ if field.Anonymous() {
+ return
+ }
+
+ if field.Exported() {
+ return
+ }
+
+ for _, enc := range [...]string{"json", "xml"} {
+ if reflect.StructTag(tag).Get(enc) != "" {
+ pass.Reportf(field.Pos(), "struct field %s has %s tag but is not exported", field.Name(), enc)
+ return
+ }
+ }
+}
+
+// checkTagDuplicates checks a single struct field tag to see if any tags are
+// duplicated. nearest is the field that's closest to the field being checked,
+// while still being part of the top-level struct type.
+func checkTagDuplicates(pass *analysis.Pass, tag, key string, nearest, field *types.Var, seen *map[[2]string]token.Pos) {
+ val := reflect.StructTag(tag).Get(key)
+ if val == "-" {
+ // Ignored, even if the field is anonymous.
+ return
+ }
+ if val == "" || val[0] == ',' {
+ if field.Anonymous() {
+ typ, ok := field.Type().Underlying().(*types.Struct)
+ if !ok {
+ return
+ }
+ for i := 0; i < typ.NumFields(); i++ {
+ field := typ.Field(i)
+ if !field.Exported() {
+ continue
+ }
+ tag := typ.Tag(i)
+ checkTagDuplicates(pass, tag, key, nearest, field, seen)
+ }
+ }
+ // Ignored if the field isn't anonymous.
+ return
+ }
+ if key == "xml" && field.Name() == "XMLName" {
+ // XMLName defines the XML element name of the struct being
+ // checked. That name cannot collide with element or attribute
+ // names defined on other fields of the struct. Vet does not have a
+ // check for untagged fields of type struct defining their own name
+ // by containing a field named XMLName; see issue 18256.
+ return
+ }
+ if i := strings.Index(val, ","); i >= 0 {
+ if key == "xml" {
+ // Use a separate namespace for XML attributes.
+ for _, opt := range strings.Split(val[i:], ",") {
+ if opt == "attr" {
+ key += " attribute" // Key is part of the error message.
+ break
+ }
+ }
+ }
+ val = val[:i]
+ }
+ if *seen == nil {
+ *seen = map[[2]string]token.Pos{}
+ }
+ if pos, ok := (*seen)[[2]string{key, val}]; ok {
+ posn := pass.Fset.Position(pos)
+ posn.Filename = filepath.Base(posn.Filename)
+ posn.Column = 0
+ pass.Reportf(nearest.Pos(), "struct field %s repeats %s tag %q also at %s", field.Name(), key, val, posn)
+ } else {
+ (*seen)[[2]string{key, val}] = field.Pos()
+ }
+}
+
+var (
+ errTagSyntax = errors.New("bad syntax for struct tag pair")
+ errTagKeySyntax = errors.New("bad syntax for struct tag key")
+ errTagValueSyntax = errors.New("bad syntax for struct tag value")
+ errTagValueSpace = errors.New("suspicious space in struct tag value")
+ errTagSpace = errors.New("key:\"value\" pairs not separated by spaces")
+)
+
+// validateStructTag parses the struct tag and returns an error if it is not
+// in the canonical format, which is a space-separated list of key:"value"
+// settings. The value may contain spaces.
+func validateStructTag(tag string) error {
+ // This code is based on the StructTag.Get code in package reflect.
+
+ n := 0
+ for ; tag != ""; n++ {
+ if n > 0 && tag != "" && tag[0] != ' ' {
+ // More restrictive than reflect, but catches likely mistakes
+ // like `x:"foo",y:"bar"`, which parses as `x:"foo" ,y:"bar"` with second key ",y".
+ return errTagSpace
+ }
+ // Skip leading space.
+ i := 0
+ for i < len(tag) && tag[i] == ' ' {
+ i++
+ }
+ tag = tag[i:]
+ if tag == "" {
+ break
+ }
+
+ // Scan to colon. A space, a quote or a control character is a syntax error.
+ // Strictly speaking, control chars include the range [0x7f, 0x9f], not just
+ // [0x00, 0x1f], but in practice, we ignore the multi-byte control characters
+ // as it is simpler to inspect the tag's bytes than the tag's runes.
+ i = 0
+ for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f {
+ i++
+ }
+ if i == 0 {
+ return errTagKeySyntax
+ }
+ if i+1 >= len(tag) || tag[i] != ':' {
+ return errTagSyntax
+ }
+ if tag[i+1] != '"' {
+ return errTagValueSyntax
+ }
+ key := tag[:i]
+ tag = tag[i+1:]
+
+ // Scan quoted string to find value.
+ i = 1
+ for i < len(tag) && tag[i] != '"' {
+ if tag[i] == '\\' {
+ i++
+ }
+ i++
+ }
+ if i >= len(tag) {
+ return errTagValueSyntax
+ }
+ qvalue := tag[:i+1]
+ tag = tag[i+1:]
+
+ value, err := strconv.Unquote(qvalue)
+ if err != nil {
+ return errTagValueSyntax
+ }
+
+ if !checkTagSpaces[key] {
+ continue
+ }
+
+ switch key {
+ case "xml":
+ // If the first or last character in the XML tag is a space, it is
+ // suspicious.
+ if strings.Trim(value, " ") != value {
+ return errTagValueSpace
+ }
+
+ // If there are multiple spaces, they are suspicious.
+ if strings.Count(value, " ") > 1 {
+ return errTagValueSpace
+ }
+
+ // If there is no comma, skip the rest of the checks.
+ comma := strings.IndexRune(value, ',')
+ if comma < 0 {
+ continue
+ }
+
+ // If the character before a comma is a space, this is suspicious.
+ if comma > 0 && value[comma-1] == ' ' {
+ return errTagValueSpace
+ }
+ value = value[comma+1:]
+ case "json":
+ // JSON allows using spaces in the name, so skip it.
+ comma := strings.IndexRune(value, ',')
+ if comma < 0 {
+ continue
+ }
+ value = value[comma+1:]
+ }
+
+ if strings.IndexByte(value, ' ') >= 0 {
+ return errTagValueSpace
+ }
+ }
+ return nil
+}
--- /dev/null
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package tests defines an Analyzer that checks for common mistaken
+// usages of tests and examples.
+package tests
+
+import (
+ "go/ast"
+ "go/types"
+ "strings"
+ "unicode"
+ "unicode/utf8"
+
+ "golang.org/x/tools/go/analysis"
+)
+
+const Doc = `check for common mistaken usages of tests and examples
+
+The tests checker walks Test, Benchmark and Example functions checking
+malformed names, wrong signatures and examples documenting non-existent
+identifiers.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "tests",
+ Doc: Doc,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ for _, f := range pass.Files {
+ if !strings.HasSuffix(pass.Fset.File(f.Pos()).Name(), "_test.go") {
+ continue
+ }
+ for _, decl := range f.Decls {
+ fn, ok := decl.(*ast.FuncDecl)
+ if !ok || fn.Recv != nil {
+ // Ignore non-functions or functions with receivers.
+ continue
+ }
+
+ switch {
+ case strings.HasPrefix(fn.Name.Name, "Example"):
+ checkExample(pass, fn)
+ case strings.HasPrefix(fn.Name.Name, "Test"):
+ checkTest(pass, fn, "Test")
+ case strings.HasPrefix(fn.Name.Name, "Benchmark"):
+ checkTest(pass, fn, "Benchmark")
+ }
+ }
+ }
+ return nil, nil
+}
+
+func isExampleSuffix(s string) bool {
+ r, size := utf8.DecodeRuneInString(s)
+ return size > 0 && unicode.IsLower(r)
+}
+
+func isTestSuffix(name string) bool {
+ if len(name) == 0 {
+ // "Test" is ok.
+ return true
+ }
+ r, _ := utf8.DecodeRuneInString(name)
+ return !unicode.IsLower(r)
+}
+
+func isTestParam(typ ast.Expr, wantType string) bool {
+ ptr, ok := typ.(*ast.StarExpr)
+ if !ok {
+ // Not a pointer.
+ return false
+ }
+ // No easy way of making sure it's a *testing.T or *testing.B:
+ // ensure the name of the type matches.
+ if name, ok := ptr.X.(*ast.Ident); ok {
+ return name.Name == wantType
+ }
+ if sel, ok := ptr.X.(*ast.SelectorExpr); ok {
+ return sel.Sel.Name == wantType
+ }
+ return false
+}
+
+func lookup(pkg *types.Package, name string) types.Object {
+ if o := pkg.Scope().Lookup(name); o != nil {
+ return o
+ }
+
+ // If this package is ".../foo_test" and it imports a package
+ // ".../foo", try looking in the latter package.
+ // This heuristic should work even on build systems that do not
+ // record any special link between the packages.
+ if basePath := strings.TrimSuffix(pkg.Path(), "_test"); basePath != pkg.Path() {
+ for _, imp := range pkg.Imports() {
+ if imp.Path() == basePath {
+ return imp.Scope().Lookup(name)
+ }
+ }
+ }
+ return nil
+}
+
+func checkExample(pass *analysis.Pass, fn *ast.FuncDecl) {
+ fnName := fn.Name.Name
+ if params := fn.Type.Params; len(params.List) != 0 {
+ pass.Reportf(fn.Pos(), "%s should be niladic", fnName)
+ }
+ if results := fn.Type.Results; results != nil && len(results.List) != 0 {
+ pass.Reportf(fn.Pos(), "%s should return nothing", fnName)
+ }
+
+ if fnName == "Example" {
+ // Nothing more to do.
+ return
+ }
+
+ var (
+ exName = strings.TrimPrefix(fnName, "Example")
+ elems = strings.SplitN(exName, "_", 3)
+ ident = elems[0]
+ obj = lookup(pass.Pkg, ident)
+ )
+ if ident != "" && obj == nil {
+ // Check ExampleFoo and ExampleBadFoo.
+ pass.Reportf(fn.Pos(), "%s refers to unknown identifier: %s", fnName, ident)
+ // Abort since obj is absent and no subsequent checks can be performed.
+ return
+ }
+ if len(elems) < 2 {
+ // Nothing more to do.
+ return
+ }
+
+ if ident == "" {
+ // Check Example_suffix and Example_BadSuffix.
+ if residual := strings.TrimPrefix(exName, "_"); !isExampleSuffix(residual) {
+ pass.Reportf(fn.Pos(), "%s has malformed example suffix: %s", fnName, residual)
+ }
+ return
+ }
+
+ mmbr := elems[1]
+ if !isExampleSuffix(mmbr) {
+ // Check ExampleFoo_Method and ExampleFoo_BadMethod.
+ if obj, _, _ := types.LookupFieldOrMethod(obj.Type(), true, obj.Pkg(), mmbr); obj == nil {
+ pass.Reportf(fn.Pos(), "%s refers to unknown field or method: %s.%s", fnName, ident, mmbr)
+ }
+ }
+ if len(elems) == 3 && !isExampleSuffix(elems[2]) {
+ // Check ExampleFoo_Method_suffix and ExampleFoo_Method_Badsuffix.
+ pass.Reportf(fn.Pos(), "%s has malformed example suffix: %s", fnName, elems[2])
+ }
+}
+
+func checkTest(pass *analysis.Pass, fn *ast.FuncDecl, prefix string) {
+ // Want functions with 0 results and 1 parameter.
+ if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
+ fn.Type.Params == nil ||
+ len(fn.Type.Params.List) != 1 ||
+ len(fn.Type.Params.List[0].Names) > 1 {
+ return
+ }
+
+ // The param must look like a *testing.T or *testing.B.
+ if !isTestParam(fn.Type.Params.List[0].Type, prefix[:1]) {
+ return
+ }
+
+ if !isTestSuffix(fn.Name.Name[len(prefix):]) {
+ pass.Reportf(fn.Pos(), "%s has malformed name: first letter after '%s' must not be lowercase", fn.Name.Name, prefix)
+ }
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package unreachable defines an Analyzer that checks for unreachable code.
+package unreachable
+
+// TODO(adonovan): use the new cfg package, which is more precise.
+
+import (
+ "go/ast"
+ "go/token"
+ "log"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for unreachable code
+
+The unreachable analyzer finds statements that execution can never reach
+because they are preceded by an return statement, a call to panic, an
+infinite loop, or similar constructs.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "unreachable",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ RunDespiteErrors: true,
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.FuncDecl)(nil),
+ (*ast.FuncLit)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ var body *ast.BlockStmt
+ switch n := n.(type) {
+ case *ast.FuncDecl:
+ body = n.Body
+ case *ast.FuncLit:
+ body = n.Body
+ }
+ if body == nil {
+ return
+ }
+ d := &deadState{
+ pass: pass,
+ hasBreak: make(map[ast.Stmt]bool),
+ hasGoto: make(map[string]bool),
+ labels: make(map[string]ast.Stmt),
+ }
+ d.findLabels(body)
+ d.reachable = true
+ d.findDead(body)
+ })
+ return nil, nil
+}
+
+type deadState struct {
+ pass *analysis.Pass
+ hasBreak map[ast.Stmt]bool
+ hasGoto map[string]bool
+ labels map[string]ast.Stmt
+ breakTarget ast.Stmt
+
+ reachable bool
+}
+
+// findLabels gathers information about the labels defined and used by stmt
+// and about which statements break, whether a label is involved or not.
+func (d *deadState) findLabels(stmt ast.Stmt) {
+ switch x := stmt.(type) {
+ default:
+ log.Fatalf("%s: internal error in findLabels: unexpected statement %T", d.pass.Fset.Position(x.Pos()), x)
+
+ case *ast.AssignStmt,
+ *ast.BadStmt,
+ *ast.DeclStmt,
+ *ast.DeferStmt,
+ *ast.EmptyStmt,
+ *ast.ExprStmt,
+ *ast.GoStmt,
+ *ast.IncDecStmt,
+ *ast.ReturnStmt,
+ *ast.SendStmt:
+ // no statements inside
+
+ case *ast.BlockStmt:
+ for _, stmt := range x.List {
+ d.findLabels(stmt)
+ }
+
+ case *ast.BranchStmt:
+ switch x.Tok {
+ case token.GOTO:
+ if x.Label != nil {
+ d.hasGoto[x.Label.Name] = true
+ }
+
+ case token.BREAK:
+ stmt := d.breakTarget
+ if x.Label != nil {
+ stmt = d.labels[x.Label.Name]
+ }
+ if stmt != nil {
+ d.hasBreak[stmt] = true
+ }
+ }
+
+ case *ast.IfStmt:
+ d.findLabels(x.Body)
+ if x.Else != nil {
+ d.findLabels(x.Else)
+ }
+
+ case *ast.LabeledStmt:
+ d.labels[x.Label.Name] = x.Stmt
+ d.findLabels(x.Stmt)
+
+ // These cases are all the same, but the x.Body only works
+ // when the specific type of x is known, so the cases cannot
+ // be merged.
+ case *ast.ForStmt:
+ outer := d.breakTarget
+ d.breakTarget = x
+ d.findLabels(x.Body)
+ d.breakTarget = outer
+
+ case *ast.RangeStmt:
+ outer := d.breakTarget
+ d.breakTarget = x
+ d.findLabels(x.Body)
+ d.breakTarget = outer
+
+ case *ast.SelectStmt:
+ outer := d.breakTarget
+ d.breakTarget = x
+ d.findLabels(x.Body)
+ d.breakTarget = outer
+
+ case *ast.SwitchStmt:
+ outer := d.breakTarget
+ d.breakTarget = x
+ d.findLabels(x.Body)
+ d.breakTarget = outer
+
+ case *ast.TypeSwitchStmt:
+ outer := d.breakTarget
+ d.breakTarget = x
+ d.findLabels(x.Body)
+ d.breakTarget = outer
+
+ case *ast.CommClause:
+ for _, stmt := range x.Body {
+ d.findLabels(stmt)
+ }
+
+ case *ast.CaseClause:
+ for _, stmt := range x.Body {
+ d.findLabels(stmt)
+ }
+ }
+}
+
+// findDead walks the statement looking for dead code.
+// If d.reachable is false on entry, stmt itself is dead.
+// When findDead returns, d.reachable tells whether the
+// statement following stmt is reachable.
+func (d *deadState) findDead(stmt ast.Stmt) {
+ // Is this a labeled goto target?
+ // If so, assume it is reachable due to the goto.
+ // This is slightly conservative, in that we don't
+ // check that the goto is reachable, so
+ // L: goto L
+ // will not provoke a warning.
+ // But it's good enough.
+ if x, isLabel := stmt.(*ast.LabeledStmt); isLabel && d.hasGoto[x.Label.Name] {
+ d.reachable = true
+ }
+
+ if !d.reachable {
+ switch stmt.(type) {
+ case *ast.EmptyStmt:
+ // do not warn about unreachable empty statements
+ default:
+ d.pass.Reportf(stmt.Pos(), "unreachable code")
+ d.reachable = true // silence error about next statement
+ }
+ }
+
+ switch x := stmt.(type) {
+ default:
+ log.Fatalf("%s: internal error in findDead: unexpected statement %T", d.pass.Fset.Position(x.Pos()), x)
+
+ case *ast.AssignStmt,
+ *ast.BadStmt,
+ *ast.DeclStmt,
+ *ast.DeferStmt,
+ *ast.EmptyStmt,
+ *ast.GoStmt,
+ *ast.IncDecStmt,
+ *ast.SendStmt:
+ // no control flow
+
+ case *ast.BlockStmt:
+ for _, stmt := range x.List {
+ d.findDead(stmt)
+ }
+
+ case *ast.BranchStmt:
+ switch x.Tok {
+ case token.BREAK, token.GOTO, token.FALLTHROUGH:
+ d.reachable = false
+ case token.CONTINUE:
+ // NOTE: We accept "continue" statements as terminating.
+ // They are not necessary in the spec definition of terminating,
+ // because a continue statement cannot be the final statement
+ // before a return. But for the more general problem of syntactically
+ // identifying dead code, continue redirects control flow just
+ // like the other terminating statements.
+ d.reachable = false
+ }
+
+ case *ast.ExprStmt:
+ // Call to panic?
+ call, ok := x.X.(*ast.CallExpr)
+ if ok {
+ name, ok := call.Fun.(*ast.Ident)
+ if ok && name.Name == "panic" && name.Obj == nil {
+ d.reachable = false
+ }
+ }
+
+ case *ast.ForStmt:
+ d.findDead(x.Body)
+ d.reachable = x.Cond != nil || d.hasBreak[x]
+
+ case *ast.IfStmt:
+ d.findDead(x.Body)
+ if x.Else != nil {
+ r := d.reachable
+ d.reachable = true
+ d.findDead(x.Else)
+ d.reachable = d.reachable || r
+ } else {
+ // might not have executed if statement
+ d.reachable = true
+ }
+
+ case *ast.LabeledStmt:
+ d.findDead(x.Stmt)
+
+ case *ast.RangeStmt:
+ d.findDead(x.Body)
+ d.reachable = true
+
+ case *ast.ReturnStmt:
+ d.reachable = false
+
+ case *ast.SelectStmt:
+ // NOTE: Unlike switch and type switch below, we don't care
+ // whether a select has a default, because a select without a
+ // default blocks until one of the cases can run. That's different
+ // from a switch without a default, which behaves like it has
+ // a default with an empty body.
+ anyReachable := false
+ for _, comm := range x.Body.List {
+ d.reachable = true
+ for _, stmt := range comm.(*ast.CommClause).Body {
+ d.findDead(stmt)
+ }
+ anyReachable = anyReachable || d.reachable
+ }
+ d.reachable = anyReachable || d.hasBreak[x]
+
+ case *ast.SwitchStmt:
+ anyReachable := false
+ hasDefault := false
+ for _, cas := range x.Body.List {
+ cc := cas.(*ast.CaseClause)
+ if cc.List == nil {
+ hasDefault = true
+ }
+ d.reachable = true
+ for _, stmt := range cc.Body {
+ d.findDead(stmt)
+ }
+ anyReachable = anyReachable || d.reachable
+ }
+ d.reachable = anyReachable || d.hasBreak[x] || !hasDefault
+
+ case *ast.TypeSwitchStmt:
+ anyReachable := false
+ hasDefault := false
+ for _, cas := range x.Body.List {
+ cc := cas.(*ast.CaseClause)
+ if cc.List == nil {
+ hasDefault = true
+ }
+ d.reachable = true
+ for _, stmt := range cc.Body {
+ d.findDead(stmt)
+ }
+ anyReachable = anyReachable || d.reachable
+ }
+ d.reachable = anyReachable || d.hasBreak[x] || !hasDefault
+ }
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package unsafeptr defines an Analyzer that checks for invalid
+// conversions of uintptr to unsafe.Pointer.
+package unsafeptr
+
+import (
+ "go/ast"
+ "go/token"
+ "go/types"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+const Doc = `check for invalid conversions of uintptr to unsafe.Pointer
+
+The unsafeptr analyzer reports likely incorrect uses of unsafe.Pointer
+to convert integers to pointers. A conversion from uintptr to
+unsafe.Pointer is invalid if it implies that there is a uintptr-typed
+word in memory that holds a pointer value, because that word will be
+invisible to stack copying and to the garbage collector.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "unsafeptr",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.CallExpr)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ x := n.(*ast.CallExpr)
+ if len(x.Args) != 1 {
+ return
+ }
+ if hasBasicType(pass.TypesInfo, x.Fun, types.UnsafePointer) &&
+ hasBasicType(pass.TypesInfo, x.Args[0], types.Uintptr) &&
+ !isSafeUintptr(pass.TypesInfo, x.Args[0]) {
+ pass.Reportf(x.Pos(), "possible misuse of unsafe.Pointer")
+ }
+ })
+ return nil, nil
+}
+
+// isSafeUintptr reports whether x - already known to be a uintptr -
+// is safe to convert to unsafe.Pointer. It is safe if x is itself derived
+// directly from an unsafe.Pointer via conversion and pointer arithmetic
+// or if x is the result of reflect.Value.Pointer or reflect.Value.UnsafeAddr
+// or obtained from the Data field of a *reflect.SliceHeader or *reflect.StringHeader.
+func isSafeUintptr(info *types.Info, x ast.Expr) bool {
+ switch x := x.(type) {
+ case *ast.ParenExpr:
+ return isSafeUintptr(info, x.X)
+
+ case *ast.SelectorExpr:
+ switch x.Sel.Name {
+ case "Data":
+ // reflect.SliceHeader and reflect.StringHeader are okay,
+ // but only if they are pointing at a real slice or string.
+ // It's not okay to do:
+ // var x SliceHeader
+ // x.Data = uintptr(unsafe.Pointer(...))
+ // ... use x ...
+ // p := unsafe.Pointer(x.Data)
+ // because in the middle the garbage collector doesn't
+ // see x.Data as a pointer and so x.Data may be dangling
+ // by the time we get to the conversion at the end.
+ // For now approximate by saying that *Header is okay
+ // but Header is not.
+ pt, ok := info.Types[x.X].Type.(*types.Pointer)
+ if ok {
+ t, ok := pt.Elem().(*types.Named)
+ if ok && t.Obj().Pkg().Path() == "reflect" {
+ switch t.Obj().Name() {
+ case "StringHeader", "SliceHeader":
+ return true
+ }
+ }
+ }
+ }
+
+ case *ast.CallExpr:
+ switch len(x.Args) {
+ case 0:
+ // maybe call to reflect.Value.Pointer or reflect.Value.UnsafeAddr.
+ sel, ok := x.Fun.(*ast.SelectorExpr)
+ if !ok {
+ break
+ }
+ switch sel.Sel.Name {
+ case "Pointer", "UnsafeAddr":
+ t, ok := info.Types[sel.X].Type.(*types.Named)
+ if ok && t.Obj().Pkg().Path() == "reflect" && t.Obj().Name() == "Value" {
+ return true
+ }
+ }
+
+ case 1:
+ // maybe conversion of uintptr to unsafe.Pointer
+ return hasBasicType(info, x.Fun, types.Uintptr) &&
+ hasBasicType(info, x.Args[0], types.UnsafePointer)
+ }
+
+ case *ast.BinaryExpr:
+ switch x.Op {
+ case token.ADD, token.SUB, token.AND_NOT:
+ return isSafeUintptr(info, x.X) && !isSafeUintptr(info, x.Y)
+ }
+ }
+ return false
+}
+
+// hasBasicType reports whether x's type is a types.Basic with the given kind.
+func hasBasicType(info *types.Info, x ast.Expr, kind types.BasicKind) bool {
+ t := info.Types[x].Type
+ if t != nil {
+ t = t.Underlying()
+ }
+ b, ok := t.(*types.Basic)
+ return ok && b.Kind() == kind
+}
--- /dev/null
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package unusedresult defines an analyzer that checks for unused
+// results of calls to certain pure functions.
+package unusedresult
+
+import (
+ "go/ast"
+ "go/token"
+ "go/types"
+ "sort"
+ "strings"
+
+ "golang.org/x/tools/go/analysis"
+ "golang.org/x/tools/go/analysis/passes/inspect"
+ "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+ "golang.org/x/tools/go/ast/inspector"
+)
+
+// TODO(adonovan): make this analysis modular: export a mustUseResult
+// fact for each function that tail-calls one of the functions that we
+// check, and check those functions too.
+
+const Doc = `check for unused results of calls to some functions
+
+Some functions like fmt.Errorf return a result and have no side effects,
+so it is always a mistake to discard the result. This analyzer reports
+calls to certain functions in which the result of the call is ignored.
+
+The set of functions may be controlled using flags.`
+
+var Analyzer = &analysis.Analyzer{
+ Name: "unusedresult",
+ Doc: Doc,
+ Requires: []*analysis.Analyzer{inspect.Analyzer},
+ Run: run,
+}
+
+// flags
+var funcs, stringMethods stringSetFlag
+
+func init() {
+ // TODO(adonovan): provide a comment syntax to allow users to
+ // add their functions to this set using facts.
+ funcs.Set("errors.New,fmt.Errorf,fmt.Sprintf,fmt.Sprint,sort.Reverse")
+ Analyzer.Flags.Var(&funcs, "funcs",
+ "comma-separated list of functions whose results must be used")
+
+ stringMethods.Set("Error,String")
+ Analyzer.Flags.Var(&stringMethods, "stringmethods",
+ "comma-separated list of names of methods of type func() string whose results must be used")
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+ inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+ nodeFilter := []ast.Node{
+ (*ast.ExprStmt)(nil),
+ }
+ inspect.Preorder(nodeFilter, func(n ast.Node) {
+ call, ok := analysisutil.Unparen(n.(*ast.ExprStmt).X).(*ast.CallExpr)
+ if !ok {
+ return // not a call statement
+ }
+ fun := analysisutil.Unparen(call.Fun)
+
+ if pass.TypesInfo.Types[fun].IsType() {
+ return // a conversion, not a call
+ }
+
+ selector, ok := fun.(*ast.SelectorExpr)
+ if !ok {
+ return // neither a method call nor a qualified ident
+ }
+
+ sel, ok := pass.TypesInfo.Selections[selector]
+ if ok && sel.Kind() == types.MethodVal {
+ // method (e.g. foo.String())
+ obj := sel.Obj().(*types.Func)
+ sig := sel.Type().(*types.Signature)
+ if types.Identical(sig, sigNoArgsStringResult) {
+ if stringMethods[obj.Name()] {
+ pass.Reportf(call.Lparen, "result of (%s).%s call not used",
+ sig.Recv().Type(), obj.Name())
+ }
+ }
+ } else if !ok {
+ // package-qualified function (e.g. fmt.Errorf)
+ obj := pass.TypesInfo.Uses[selector.Sel]
+ if obj, ok := obj.(*types.Func); ok {
+ qname := obj.Pkg().Path() + "." + obj.Name()
+ if funcs[qname] {
+ pass.Reportf(call.Lparen, "result of %v call not used", qname)
+ }
+ }
+ }
+ })
+ return nil, nil
+}
+
+// func() string
+var sigNoArgsStringResult = types.NewSignature(nil, nil,
+ types.NewTuple(types.NewVar(token.NoPos, nil, "", types.Typ[types.String])),
+ false)
+
+type stringSetFlag map[string]bool
+
+func (ss *stringSetFlag) String() string {
+ var items []string
+ for item := range *ss {
+ items = append(items, item)
+ }
+ sort.Strings(items)
+ return strings.Join(items, ",")
+}
+
+func (ss *stringSetFlag) Set(s string) error {
+ m := make(map[string]bool) // clobber previous value
+ if s != "" {
+ for _, name := range strings.Split(s, ",") {
+ if name == "" {
+ continue // TODO: report error? proceed?
+ }
+ m[name] = true
+ }
+ }
+ *ss = m
+ return nil
+}
--- /dev/null
+package analysis
+
+import (
+ "fmt"
+ "reflect"
+ "unicode"
+)
+
+// Validate reports an error if any of the analyzers are misconfigured.
+// Checks include:
+// that the name is a valid identifier;
+// that analyzer names are unique;
+// that the Requires graph is acylic;
+// that analyzer fact types are unique;
+// that each fact type is a pointer.
+func Validate(analyzers []*Analyzer) error {
+ names := make(map[string]bool)
+
+ // Map each fact type to its sole generating analyzer.
+ factTypes := make(map[reflect.Type]*Analyzer)
+
+ // Traverse the Requires graph, depth first.
+ const (
+ white = iota
+ grey
+ black
+ finished
+ )
+ color := make(map[*Analyzer]uint8)
+ var visit func(a *Analyzer) error
+ visit = func(a *Analyzer) error {
+ if a == nil {
+ return fmt.Errorf("nil *Analyzer")
+ }
+ if color[a] == white {
+ color[a] = grey
+
+ // names
+ if !validIdent(a.Name) {
+ return fmt.Errorf("invalid analyzer name %q", a)
+ }
+ if names[a.Name] {
+ return fmt.Errorf("duplicate analyzer name %q", a)
+ }
+ names[a.Name] = true
+
+ if a.Doc == "" {
+ return fmt.Errorf("analyzer %q is undocumented", a)
+ }
+
+ // fact types
+ for _, f := range a.FactTypes {
+ if f == nil {
+ return fmt.Errorf("analyzer %s has nil FactType", a)
+ }
+ t := reflect.TypeOf(f)
+ if prev := factTypes[t]; prev != nil {
+ return fmt.Errorf("fact type %s registered by two analyzers: %v, %v",
+ t, a, prev)
+ }
+ if t.Kind() != reflect.Ptr {
+ return fmt.Errorf("%s: fact type %s is not a pointer", a, t)
+ }
+ factTypes[t] = a
+ }
+
+ // recursion
+ for i, req := range a.Requires {
+ if err := visit(req); err != nil {
+ return fmt.Errorf("%s.Requires[%d]: %v", a.Name, i, err)
+ }
+ }
+ color[a] = black
+ }
+
+ return nil
+ }
+ for _, a := range analyzers {
+ if err := visit(a); err != nil {
+ return err
+ }
+ }
+
+ // Reject duplicates among analyzers.
+ // Precondition: color[a] == black.
+ // Postcondition: color[a] == finished.
+ for _, a := range analyzers {
+ if color[a] == finished {
+ return fmt.Errorf("duplicate analyzer: %s", a.Name)
+ }
+ color[a] = finished
+ }
+
+ return nil
+}
+
+func validIdent(name string) bool {
+ for i, r := range name {
+ if !(r == '_' || unicode.IsLetter(r) || i > 0 && unicode.IsDigit(r)) {
+ return false
+ }
+ }
+ return name != ""
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package astutil
+
+// This file defines utilities for working with source positions.
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "sort"
+)
+
+// PathEnclosingInterval returns the node that encloses the source
+// interval [start, end), and all its ancestors up to the AST root.
+//
+// The definition of "enclosing" used by this function considers
+// additional whitespace abutting a node to be enclosed by it.
+// In this example:
+//
+// z := x + y // add them
+// <-A->
+// <----B----->
+//
+// the ast.BinaryExpr(+) node is considered to enclose interval B
+// even though its [Pos()..End()) is actually only interval A.
+// This behaviour makes user interfaces more tolerant of imperfect
+// input.
+//
+// This function treats tokens as nodes, though they are not included
+// in the result. e.g. PathEnclosingInterval("+") returns the
+// enclosing ast.BinaryExpr("x + y").
+//
+// If start==end, the 1-char interval following start is used instead.
+//
+// The 'exact' result is true if the interval contains only path[0]
+// and perhaps some adjacent whitespace. It is false if the interval
+// overlaps multiple children of path[0], or if it contains only
+// interior whitespace of path[0].
+// In this example:
+//
+// z := x + y // add them
+// <--C--> <---E-->
+// ^
+// D
+//
+// intervals C, D and E are inexact. C is contained by the
+// z-assignment statement, because it spans three of its children (:=,
+// x, +). So too is the 1-char interval D, because it contains only
+// interior whitespace of the assignment. E is considered interior
+// whitespace of the BlockStmt containing the assignment.
+//
+// Precondition: [start, end) both lie within the same file as root.
+// TODO(adonovan): return (nil, false) in this case and remove precond.
+// Requires FileSet; see loader.tokenFileContainsPos.
+//
+// Postcondition: path is never nil; it always contains at least 'root'.
+//
+func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
+ // fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging
+
+ // Precondition: node.[Pos..End) and adjoining whitespace contain [start, end).
+ var visit func(node ast.Node) bool
+ visit = func(node ast.Node) bool {
+ path = append(path, node)
+
+ nodePos := node.Pos()
+ nodeEnd := node.End()
+
+ // fmt.Printf("visit(%T, %d, %d)\n", node, nodePos, nodeEnd) // debugging
+
+ // Intersect [start, end) with interval of node.
+ if start < nodePos {
+ start = nodePos
+ }
+ if end > nodeEnd {
+ end = nodeEnd
+ }
+
+ // Find sole child that contains [start, end).
+ children := childrenOf(node)
+ l := len(children)
+ for i, child := range children {
+ // [childPos, childEnd) is unaugmented interval of child.
+ childPos := child.Pos()
+ childEnd := child.End()
+
+ // [augPos, augEnd) is whitespace-augmented interval of child.
+ augPos := childPos
+ augEnd := childEnd
+ if i > 0 {
+ augPos = children[i-1].End() // start of preceding whitespace
+ }
+ if i < l-1 {
+ nextChildPos := children[i+1].Pos()
+ // Does [start, end) lie between child and next child?
+ if start >= augEnd && end <= nextChildPos {
+ return false // inexact match
+ }
+ augEnd = nextChildPos // end of following whitespace
+ }
+
+ // fmt.Printf("\tchild %d: [%d..%d)\tcontains interval [%d..%d)?\n",
+ // i, augPos, augEnd, start, end) // debugging
+
+ // Does augmented child strictly contain [start, end)?
+ if augPos <= start && end <= augEnd {
+ _, isToken := child.(tokenNode)
+ return isToken || visit(child)
+ }
+
+ // Does [start, end) overlap multiple children?
+ // i.e. left-augmented child contains start
+ // but LR-augmented child does not contain end.
+ if start < childEnd && end > augEnd {
+ break
+ }
+ }
+
+ // No single child contained [start, end),
+ // so node is the result. Is it exact?
+
+ // (It's tempting to put this condition before the
+ // child loop, but it gives the wrong result in the
+ // case where a node (e.g. ExprStmt) and its sole
+ // child have equal intervals.)
+ if start == nodePos && end == nodeEnd {
+ return true // exact match
+ }
+
+ return false // inexact: overlaps multiple children
+ }
+
+ if start > end {
+ start, end = end, start
+ }
+
+ if start < root.End() && end > root.Pos() {
+ if start == end {
+ end = start + 1 // empty interval => interval of size 1
+ }
+ exact = visit(root)
+
+ // Reverse the path:
+ for i, l := 0, len(path); i < l/2; i++ {
+ path[i], path[l-1-i] = path[l-1-i], path[i]
+ }
+ } else {
+ // Selection lies within whitespace preceding the
+ // first (or following the last) declaration in the file.
+ // The result nonetheless always includes the ast.File.
+ path = append(path, root)
+ }
+
+ return
+}
+
+// tokenNode is a dummy implementation of ast.Node for a single token.
+// They are used transiently by PathEnclosingInterval but never escape
+// this package.
+//
+type tokenNode struct {
+ pos token.Pos
+ end token.Pos
+}
+
+func (n tokenNode) Pos() token.Pos {
+ return n.pos
+}
+
+func (n tokenNode) End() token.Pos {
+ return n.end
+}
+
+func tok(pos token.Pos, len int) ast.Node {
+ return tokenNode{pos, pos + token.Pos(len)}
+}
+
+// childrenOf returns the direct non-nil children of ast.Node n.
+// It may include fake ast.Node implementations for bare tokens.
+// it is not safe to call (e.g.) ast.Walk on such nodes.
+//
+func childrenOf(n ast.Node) []ast.Node {
+ var children []ast.Node
+
+ // First add nodes for all true subtrees.
+ ast.Inspect(n, func(node ast.Node) bool {
+ if node == n { // push n
+ return true // recur
+ }
+ if node != nil { // push child
+ children = append(children, node)
+ }
+ return false // no recursion
+ })
+
+ // Then add fake Nodes for bare tokens.
+ switch n := n.(type) {
+ case *ast.ArrayType:
+ children = append(children,
+ tok(n.Lbrack, len("[")),
+ tok(n.Elt.End(), len("]")))
+
+ case *ast.AssignStmt:
+ children = append(children,
+ tok(n.TokPos, len(n.Tok.String())))
+
+ case *ast.BasicLit:
+ children = append(children,
+ tok(n.ValuePos, len(n.Value)))
+
+ case *ast.BinaryExpr:
+ children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+ case *ast.BlockStmt:
+ children = append(children,
+ tok(n.Lbrace, len("{")),
+ tok(n.Rbrace, len("}")))
+
+ case *ast.BranchStmt:
+ children = append(children,
+ tok(n.TokPos, len(n.Tok.String())))
+
+ case *ast.CallExpr:
+ children = append(children,
+ tok(n.Lparen, len("(")),
+ tok(n.Rparen, len(")")))
+ if n.Ellipsis != 0 {
+ children = append(children, tok(n.Ellipsis, len("...")))
+ }
+
+ case *ast.CaseClause:
+ if n.List == nil {
+ children = append(children,
+ tok(n.Case, len("default")))
+ } else {
+ children = append(children,
+ tok(n.Case, len("case")))
+ }
+ children = append(children, tok(n.Colon, len(":")))
+
+ case *ast.ChanType:
+ switch n.Dir {
+ case ast.RECV:
+ children = append(children, tok(n.Begin, len("<-chan")))
+ case ast.SEND:
+ children = append(children, tok(n.Begin, len("chan<-")))
+ case ast.RECV | ast.SEND:
+ children = append(children, tok(n.Begin, len("chan")))
+ }
+
+ case *ast.CommClause:
+ if n.Comm == nil {
+ children = append(children,
+ tok(n.Case, len("default")))
+ } else {
+ children = append(children,
+ tok(n.Case, len("case")))
+ }
+ children = append(children, tok(n.Colon, len(":")))
+
+ case *ast.Comment:
+ // nop
+
+ case *ast.CommentGroup:
+ // nop
+
+ case *ast.CompositeLit:
+ children = append(children,
+ tok(n.Lbrace, len("{")),
+ tok(n.Rbrace, len("{")))
+
+ case *ast.DeclStmt:
+ // nop
+
+ case *ast.DeferStmt:
+ children = append(children,
+ tok(n.Defer, len("defer")))
+
+ case *ast.Ellipsis:
+ children = append(children,
+ tok(n.Ellipsis, len("...")))
+
+ case *ast.EmptyStmt:
+ // nop
+
+ case *ast.ExprStmt:
+ // nop
+
+ case *ast.Field:
+ // TODO(adonovan): Field.{Doc,Comment,Tag}?
+
+ case *ast.FieldList:
+ children = append(children,
+ tok(n.Opening, len("(")),
+ tok(n.Closing, len(")")))
+
+ case *ast.File:
+ // TODO test: Doc
+ children = append(children,
+ tok(n.Package, len("package")))
+
+ case *ast.ForStmt:
+ children = append(children,
+ tok(n.For, len("for")))
+
+ case *ast.FuncDecl:
+ // TODO(adonovan): FuncDecl.Comment?
+
+ // Uniquely, FuncDecl breaks the invariant that
+ // preorder traversal yields tokens in lexical order:
+ // in fact, FuncDecl.Recv precedes FuncDecl.Type.Func.
+ //
+ // As a workaround, we inline the case for FuncType
+ // here and order things correctly.
+ //
+ children = nil // discard ast.Walk(FuncDecl) info subtrees
+ children = append(children, tok(n.Type.Func, len("func")))
+ if n.Recv != nil {
+ children = append(children, n.Recv)
+ }
+ children = append(children, n.Name)
+ if n.Type.Params != nil {
+ children = append(children, n.Type.Params)
+ }
+ if n.Type.Results != nil {
+ children = append(children, n.Type.Results)
+ }
+ if n.Body != nil {
+ children = append(children, n.Body)
+ }
+
+ case *ast.FuncLit:
+ // nop
+
+ case *ast.FuncType:
+ if n.Func != 0 {
+ children = append(children,
+ tok(n.Func, len("func")))
+ }
+
+ case *ast.GenDecl:
+ children = append(children,
+ tok(n.TokPos, len(n.Tok.String())))
+ if n.Lparen != 0 {
+ children = append(children,
+ tok(n.Lparen, len("(")),
+ tok(n.Rparen, len(")")))
+ }
+
+ case *ast.GoStmt:
+ children = append(children,
+ tok(n.Go, len("go")))
+
+ case *ast.Ident:
+ children = append(children,
+ tok(n.NamePos, len(n.Name)))
+
+ case *ast.IfStmt:
+ children = append(children,
+ tok(n.If, len("if")))
+
+ case *ast.ImportSpec:
+ // TODO(adonovan): ImportSpec.{Doc,EndPos}?
+
+ case *ast.IncDecStmt:
+ children = append(children,
+ tok(n.TokPos, len(n.Tok.String())))
+
+ case *ast.IndexExpr:
+ children = append(children,
+ tok(n.Lbrack, len("{")),
+ tok(n.Rbrack, len("}")))
+
+ case *ast.InterfaceType:
+ children = append(children,
+ tok(n.Interface, len("interface")))
+
+ case *ast.KeyValueExpr:
+ children = append(children,
+ tok(n.Colon, len(":")))
+
+ case *ast.LabeledStmt:
+ children = append(children,
+ tok(n.Colon, len(":")))
+
+ case *ast.MapType:
+ children = append(children,
+ tok(n.Map, len("map")))
+
+ case *ast.ParenExpr:
+ children = append(children,
+ tok(n.Lparen, len("(")),
+ tok(n.Rparen, len(")")))
+
+ case *ast.RangeStmt:
+ children = append(children,
+ tok(n.For, len("for")),
+ tok(n.TokPos, len(n.Tok.String())))
+
+ case *ast.ReturnStmt:
+ children = append(children,
+ tok(n.Return, len("return")))
+
+ case *ast.SelectStmt:
+ children = append(children,
+ tok(n.Select, len("select")))
+
+ case *ast.SelectorExpr:
+ // nop
+
+ case *ast.SendStmt:
+ children = append(children,
+ tok(n.Arrow, len("<-")))
+
+ case *ast.SliceExpr:
+ children = append(children,
+ tok(n.Lbrack, len("[")),
+ tok(n.Rbrack, len("]")))
+
+ case *ast.StarExpr:
+ children = append(children, tok(n.Star, len("*")))
+
+ case *ast.StructType:
+ children = append(children, tok(n.Struct, len("struct")))
+
+ case *ast.SwitchStmt:
+ children = append(children, tok(n.Switch, len("switch")))
+
+ case *ast.TypeAssertExpr:
+ children = append(children,
+ tok(n.Lparen-1, len(".")),
+ tok(n.Lparen, len("(")),
+ tok(n.Rparen, len(")")))
+
+ case *ast.TypeSpec:
+ // TODO(adonovan): TypeSpec.{Doc,Comment}?
+
+ case *ast.TypeSwitchStmt:
+ children = append(children, tok(n.Switch, len("switch")))
+
+ case *ast.UnaryExpr:
+ children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+ case *ast.ValueSpec:
+ // TODO(adonovan): ValueSpec.{Doc,Comment}?
+
+ case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
+ // nop
+ }
+
+ // TODO(adonovan): opt: merge the logic of ast.Inspect() into
+ // the switch above so we can make interleaved callbacks for
+ // both Nodes and Tokens in the right order and avoid the need
+ // to sort.
+ sort.Sort(byPos(children))
+
+ return children
+}
+
+type byPos []ast.Node
+
+func (sl byPos) Len() int {
+ return len(sl)
+}
+func (sl byPos) Less(i, j int) bool {
+ return sl[i].Pos() < sl[j].Pos()
+}
+func (sl byPos) Swap(i, j int) {
+ sl[i], sl[j] = sl[j], sl[i]
+}
+
+// NodeDescription returns a description of the concrete type of n suitable
+// for a user interface.
+//
+// TODO(adonovan): in some cases (e.g. Field, FieldList, Ident,
+// StarExpr) we could be much more specific given the path to the AST
+// root. Perhaps we should do that.
+//
+func NodeDescription(n ast.Node) string {
+ switch n := n.(type) {
+ case *ast.ArrayType:
+ return "array type"
+ case *ast.AssignStmt:
+ return "assignment"
+ case *ast.BadDecl:
+ return "bad declaration"
+ case *ast.BadExpr:
+ return "bad expression"
+ case *ast.BadStmt:
+ return "bad statement"
+ case *ast.BasicLit:
+ return "basic literal"
+ case *ast.BinaryExpr:
+ return fmt.Sprintf("binary %s operation", n.Op)
+ case *ast.BlockStmt:
+ return "block"
+ case *ast.BranchStmt:
+ switch n.Tok {
+ case token.BREAK:
+ return "break statement"
+ case token.CONTINUE:
+ return "continue statement"
+ case token.GOTO:
+ return "goto statement"
+ case token.FALLTHROUGH:
+ return "fall-through statement"
+ }
+ case *ast.CallExpr:
+ if len(n.Args) == 1 && !n.Ellipsis.IsValid() {
+ return "function call (or conversion)"
+ }
+ return "function call"
+ case *ast.CaseClause:
+ return "case clause"
+ case *ast.ChanType:
+ return "channel type"
+ case *ast.CommClause:
+ return "communication clause"
+ case *ast.Comment:
+ return "comment"
+ case *ast.CommentGroup:
+ return "comment group"
+ case *ast.CompositeLit:
+ return "composite literal"
+ case *ast.DeclStmt:
+ return NodeDescription(n.Decl) + " statement"
+ case *ast.DeferStmt:
+ return "defer statement"
+ case *ast.Ellipsis:
+ return "ellipsis"
+ case *ast.EmptyStmt:
+ return "empty statement"
+ case *ast.ExprStmt:
+ return "expression statement"
+ case *ast.Field:
+ // Can be any of these:
+ // struct {x, y int} -- struct field(s)
+ // struct {T} -- anon struct field
+ // interface {I} -- interface embedding
+ // interface {f()} -- interface method
+ // func (A) func(B) C -- receiver, param(s), result(s)
+ return "field/method/parameter"
+ case *ast.FieldList:
+ return "field/method/parameter list"
+ case *ast.File:
+ return "source file"
+ case *ast.ForStmt:
+ return "for loop"
+ case *ast.FuncDecl:
+ return "function declaration"
+ case *ast.FuncLit:
+ return "function literal"
+ case *ast.FuncType:
+ return "function type"
+ case *ast.GenDecl:
+ switch n.Tok {
+ case token.IMPORT:
+ return "import declaration"
+ case token.CONST:
+ return "constant declaration"
+ case token.TYPE:
+ return "type declaration"
+ case token.VAR:
+ return "variable declaration"
+ }
+ case *ast.GoStmt:
+ return "go statement"
+ case *ast.Ident:
+ return "identifier"
+ case *ast.IfStmt:
+ return "if statement"
+ case *ast.ImportSpec:
+ return "import specification"
+ case *ast.IncDecStmt:
+ if n.Tok == token.INC {
+ return "increment statement"
+ }
+ return "decrement statement"
+ case *ast.IndexExpr:
+ return "index expression"
+ case *ast.InterfaceType:
+ return "interface type"
+ case *ast.KeyValueExpr:
+ return "key/value association"
+ case *ast.LabeledStmt:
+ return "statement label"
+ case *ast.MapType:
+ return "map type"
+ case *ast.Package:
+ return "package"
+ case *ast.ParenExpr:
+ return "parenthesized " + NodeDescription(n.X)
+ case *ast.RangeStmt:
+ return "range loop"
+ case *ast.ReturnStmt:
+ return "return statement"
+ case *ast.SelectStmt:
+ return "select statement"
+ case *ast.SelectorExpr:
+ return "selector"
+ case *ast.SendStmt:
+ return "channel send"
+ case *ast.SliceExpr:
+ return "slice expression"
+ case *ast.StarExpr:
+ return "*-operation" // load/store expr or pointer type
+ case *ast.StructType:
+ return "struct type"
+ case *ast.SwitchStmt:
+ return "switch statement"
+ case *ast.TypeAssertExpr:
+ return "type assertion"
+ case *ast.TypeSpec:
+ return "type specification"
+ case *ast.TypeSwitchStmt:
+ return "type switch"
+ case *ast.UnaryExpr:
+ return fmt.Sprintf("unary %s operation", n.Op)
+ case *ast.ValueSpec:
+ return "value specification"
+
+ }
+ panic(fmt.Sprintf("unexpected node type: %T", n))
+}
--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package astutil contains common utilities for working with the Go AST.
+package astutil // import "golang.org/x/tools/go/ast/astutil"
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "strconv"
+ "strings"
+)
+
+// AddImport adds the import path to the file f, if absent.
+func AddImport(fset *token.FileSet, f *ast.File, ipath string) (added bool) {
+ return AddNamedImport(fset, f, "", ipath)
+}
+
+// AddNamedImport adds the import path to the file f, if absent.
+// If name is not empty, it is used to rename the import.
+//
+// For example, calling
+// AddNamedImport(fset, f, "pathpkg", "path")
+// adds
+// import pathpkg "path"
+func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
+ if imports(f, ipath) {
+ return false
+ }
+
+ newImport := &ast.ImportSpec{
+ Path: &ast.BasicLit{
+ Kind: token.STRING,
+ Value: strconv.Quote(ipath),
+ },
+ }
+ if name != "" {
+ newImport.Name = &ast.Ident{Name: name}
+ }
+
+ // Find an import decl to add to.
+ // The goal is to find an existing import
+ // whose import path has the longest shared
+ // prefix with ipath.
+ var (
+ bestMatch = -1 // length of longest shared prefix
+ lastImport = -1 // index in f.Decls of the file's final import decl
+ impDecl *ast.GenDecl // import decl containing the best match
+ impIndex = -1 // spec index in impDecl containing the best match
+
+ isThirdPartyPath = isThirdParty(ipath)
+ )
+ for i, decl := range f.Decls {
+ gen, ok := decl.(*ast.GenDecl)
+ if ok && gen.Tok == token.IMPORT {
+ lastImport = i
+ // Do not add to import "C", to avoid disrupting the
+ // association with its doc comment, breaking cgo.
+ if declImports(gen, "C") {
+ continue
+ }
+
+ // Match an empty import decl if that's all that is available.
+ if len(gen.Specs) == 0 && bestMatch == -1 {
+ impDecl = gen
+ }
+
+ // Compute longest shared prefix with imports in this group and find best
+ // matched import spec.
+ // 1. Always prefer import spec with longest shared prefix.
+ // 2. While match length is 0,
+ // - for stdlib package: prefer first import spec.
+ // - for third party package: prefer first third party import spec.
+ // We cannot use last import spec as best match for third party package
+ // because grouped imports are usually placed last by goimports -local
+ // flag.
+ // See issue #19190.
+ seenAnyThirdParty := false
+ for j, spec := range gen.Specs {
+ impspec := spec.(*ast.ImportSpec)
+ p := importPath(impspec)
+ n := matchLen(p, ipath)
+ if n > bestMatch || (bestMatch == 0 && !seenAnyThirdParty && isThirdPartyPath) {
+ bestMatch = n
+ impDecl = gen
+ impIndex = j
+ }
+ seenAnyThirdParty = seenAnyThirdParty || isThirdParty(p)
+ }
+ }
+ }
+
+ // If no import decl found, add one after the last import.
+ if impDecl == nil {
+ impDecl = &ast.GenDecl{
+ Tok: token.IMPORT,
+ }
+ if lastImport >= 0 {
+ impDecl.TokPos = f.Decls[lastImport].End()
+ } else {
+ // There are no existing imports.
+ // Our new import, preceded by a blank line, goes after the package declaration
+ // and after the comment, if any, that starts on the same line as the
+ // package declaration.
+ impDecl.TokPos = f.Package
+
+ file := fset.File(f.Package)
+ pkgLine := file.Line(f.Package)
+ for _, c := range f.Comments {
+ if file.Line(c.Pos()) > pkgLine {
+ break
+ }
+ // +2 for a blank line
+ impDecl.TokPos = c.End() + 2
+ }
+ }
+ f.Decls = append(f.Decls, nil)
+ copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
+ f.Decls[lastImport+1] = impDecl
+ }
+
+ // Insert new import at insertAt.
+ insertAt := 0
+ if impIndex >= 0 {
+ // insert after the found import
+ insertAt = impIndex + 1
+ }
+ impDecl.Specs = append(impDecl.Specs, nil)
+ copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
+ impDecl.Specs[insertAt] = newImport
+ pos := impDecl.Pos()
+ if insertAt > 0 {
+ // If there is a comment after an existing import, preserve the comment
+ // position by adding the new import after the comment.
+ if spec, ok := impDecl.Specs[insertAt-1].(*ast.ImportSpec); ok && spec.Comment != nil {
+ pos = spec.Comment.End()
+ } else {
+ // Assign same position as the previous import,
+ // so that the sorter sees it as being in the same block.
+ pos = impDecl.Specs[insertAt-1].Pos()
+ }
+ }
+ if newImport.Name != nil {
+ newImport.Name.NamePos = pos
+ }
+ newImport.Path.ValuePos = pos
+ newImport.EndPos = pos
+
+ // Clean up parens. impDecl contains at least one spec.
+ if len(impDecl.Specs) == 1 {
+ // Remove unneeded parens.
+ impDecl.Lparen = token.NoPos
+ } else if !impDecl.Lparen.IsValid() {
+ // impDecl needs parens added.
+ impDecl.Lparen = impDecl.Specs[0].Pos()
+ }
+
+ f.Imports = append(f.Imports, newImport)
+
+ if len(f.Decls) <= 1 {
+ return true
+ }
+
+ // Merge all the import declarations into the first one.
+ var first *ast.GenDecl
+ for i := 0; i < len(f.Decls); i++ {
+ decl := f.Decls[i]
+ gen, ok := decl.(*ast.GenDecl)
+ if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
+ continue
+ }
+ if first == nil {
+ first = gen
+ continue // Don't touch the first one.
+ }
+ // We now know there is more than one package in this import
+ // declaration. Ensure that it ends up parenthesized.
+ first.Lparen = first.Pos()
+ // Move the imports of the other import declaration to the first one.
+ for _, spec := range gen.Specs {
+ spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
+ first.Specs = append(first.Specs, spec)
+ }
+ f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
+ i--
+ }
+
+ return true
+}
+
+func isThirdParty(importPath string) bool {
+ // Third party package import path usually contains "." (".com", ".org", ...)
+ // This logic is taken from golang.org/x/tools/imports package.
+ return strings.Contains(importPath, ".")
+}
+
+// DeleteImport deletes the import path from the file f, if present.
+func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
+ return DeleteNamedImport(fset, f, "", path)
+}
+
+// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
+func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
+ var delspecs []*ast.ImportSpec
+ var delcomments []*ast.CommentGroup
+
+ // Find the import nodes that import path, if any.
+ for i := 0; i < len(f.Decls); i++ {
+ decl := f.Decls[i]
+ gen, ok := decl.(*ast.GenDecl)
+ if !ok || gen.Tok != token.IMPORT {
+ continue
+ }
+ for j := 0; j < len(gen.Specs); j++ {
+ spec := gen.Specs[j]
+ impspec := spec.(*ast.ImportSpec)
+ if impspec.Name == nil && name != "" {
+ continue
+ }
+ if impspec.Name != nil && impspec.Name.Name != name {
+ continue
+ }
+ if importPath(impspec) != path {
+ continue
+ }
+
+ // We found an import spec that imports path.
+ // Delete it.
+ delspecs = append(delspecs, impspec)
+ deleted = true
+ copy(gen.Specs[j:], gen.Specs[j+1:])
+ gen.Specs = gen.Specs[:len(gen.Specs)-1]
+
+ // If this was the last import spec in this decl,
+ // delete the decl, too.
+ if len(gen.Specs) == 0 {
+ copy(f.Decls[i:], f.Decls[i+1:])
+ f.Decls = f.Decls[:len(f.Decls)-1]
+ i--
+ break
+ } else if len(gen.Specs) == 1 {
+ if impspec.Doc != nil {
+ delcomments = append(delcomments, impspec.Doc)
+ }
+ if impspec.Comment != nil {
+ delcomments = append(delcomments, impspec.Comment)
+ }
+ for _, cg := range f.Comments {
+ // Found comment on the same line as the import spec.
+ if cg.End() < impspec.Pos() && fset.Position(cg.End()).Line == fset.Position(impspec.Pos()).Line {
+ delcomments = append(delcomments, cg)
+ break
+ }
+ }
+
+ spec := gen.Specs[0].(*ast.ImportSpec)
+
+ // Move the documentation right after the import decl.
+ if spec.Doc != nil {
+ for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Doc.Pos()).Line {
+ fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+ }
+ }
+ for _, cg := range f.Comments {
+ if cg.End() < spec.Pos() && fset.Position(cg.End()).Line == fset.Position(spec.Pos()).Line {
+ for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Pos()).Line {
+ fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+ }
+ break
+ }
+ }
+ }
+ if j > 0 {
+ lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
+ lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
+ line := fset.Position(impspec.Path.ValuePos).Line
+
+ // We deleted an entry but now there may be
+ // a blank line-sized hole where the import was.
+ if line-lastLine > 1 {
+ // There was a blank line immediately preceding the deleted import,
+ // so there's no need to close the hole.
+ // Do nothing.
+ } else if line != fset.File(gen.Rparen).LineCount() {
+ // There was no blank line. Close the hole.
+ fset.File(gen.Rparen).MergeLine(line)
+ }
+ }
+ j--
+ }
+ }
+
+ // Delete imports from f.Imports.
+ for i := 0; i < len(f.Imports); i++ {
+ imp := f.Imports[i]
+ for j, del := range delspecs {
+ if imp == del {
+ copy(f.Imports[i:], f.Imports[i+1:])
+ f.Imports = f.Imports[:len(f.Imports)-1]
+ copy(delspecs[j:], delspecs[j+1:])
+ delspecs = delspecs[:len(delspecs)-1]
+ i--
+ break
+ }
+ }
+ }
+
+ // Delete comments from f.Comments.
+ for i := 0; i < len(f.Comments); i++ {
+ cg := f.Comments[i]
+ for j, del := range delcomments {
+ if cg == del {
+ copy(f.Comments[i:], f.Comments[i+1:])
+ f.Comments = f.Comments[:len(f.Comments)-1]
+ copy(delcomments[j:], delcomments[j+1:])
+ delcomments = delcomments[:len(delcomments)-1]
+ i--
+ break
+ }
+ }
+ }
+
+ if len(delspecs) > 0 {
+ panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
+ }
+
+ return
+}
+
+// RewriteImport rewrites any import of path oldPath to path newPath.
+func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool) {
+ for _, imp := range f.Imports {
+ if importPath(imp) == oldPath {
+ rewrote = true
+ // record old End, because the default is to compute
+ // it using the length of imp.Path.Value.
+ imp.EndPos = imp.End()
+ imp.Path.Value = strconv.Quote(newPath)
+ }
+ }
+ return
+}
+
+// UsesImport reports whether a given import is used.
+func UsesImport(f *ast.File, path string) (used bool) {
+ spec := importSpec(f, path)
+ if spec == nil {
+ return
+ }
+
+ name := spec.Name.String()
+ switch name {
+ case "<nil>":
+ // If the package name is not explicitly specified,
+ // make an educated guess. This is not guaranteed to be correct.
+ lastSlash := strings.LastIndex(path, "/")
+ if lastSlash == -1 {
+ name = path
+ } else {
+ name = path[lastSlash+1:]
+ }
+ case "_", ".":
+ // Not sure if this import is used - err on the side of caution.
+ return true
+ }
+
+ ast.Walk(visitFn(func(n ast.Node) {
+ sel, ok := n.(*ast.SelectorExpr)
+ if ok && isTopName(sel.X, name) {
+ used = true
+ }
+ }), f)
+
+ return
+}
+
+type visitFn func(node ast.Node)
+
+func (fn visitFn) Visit(node ast.Node) ast.Visitor {
+ fn(node)
+ return fn
+}
+
+// imports returns true if f imports path.
+func imports(f *ast.File, path string) bool {
+ return importSpec(f, path) != nil
+}
+
+// importSpec returns the import spec if f imports path,
+// or nil otherwise.
+func importSpec(f *ast.File, path string) *ast.ImportSpec {
+ for _, s := range f.Imports {
+ if importPath(s) == path {
+ return s
+ }
+ }
+ return nil
+}
+
+// importPath returns the unquoted import path of s,
+// or "" if the path is not properly quoted.
+func importPath(s *ast.ImportSpec) string {
+ t, err := strconv.Unquote(s.Path.Value)
+ if err == nil {
+ return t
+ }
+ return ""
+}
+
+// declImports reports whether gen contains an import of path.
+func declImports(gen *ast.GenDecl, path string) bool {
+ if gen.Tok != token.IMPORT {
+ return false
+ }
+ for _, spec := range gen.Specs {
+ impspec := spec.(*ast.ImportSpec)
+ if importPath(impspec) == path {
+ return true
+ }
+ }
+ return false
+}
+
+// matchLen returns the length of the longest path segment prefix shared by x and y.
+func matchLen(x, y string) int {
+ n := 0
+ for i := 0; i < len(x) && i < len(y) && x[i] == y[i]; i++ {
+ if x[i] == '/' {
+ n++
+ }
+ }
+ return n
+}
+
+// isTopName returns true if n is a top-level unresolved identifier with the given name.
+func isTopName(n ast.Expr, name string) bool {
+ id, ok := n.(*ast.Ident)
+ return ok && id.Name == name && id.Obj == nil
+}
+
+// Imports returns the file imports grouped by paragraph.
+func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec {
+ var groups [][]*ast.ImportSpec
+
+ for _, decl := range f.Decls {
+ genDecl, ok := decl.(*ast.GenDecl)
+ if !ok || genDecl.Tok != token.IMPORT {
+ break
+ }
+
+ group := []*ast.ImportSpec{}
+
+ var lastLine int
+ for _, spec := range genDecl.Specs {
+ importSpec := spec.(*ast.ImportSpec)
+ pos := importSpec.Path.ValuePos
+ line := fset.Position(pos).Line
+ if lastLine > 0 && pos > 0 && line-lastLine > 1 {
+ groups = append(groups, group)
+ group = []*ast.ImportSpec{}
+ }
+ group = append(group, importSpec)
+ lastLine = line
+ }
+ groups = append(groups, group)
+ }
+
+ return groups
+}
--- /dev/null
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package astutil
+
+import (
+ "fmt"
+ "go/ast"
+ "reflect"
+ "sort"
+)
+
+// An ApplyFunc is invoked by Apply for each node n, even if n is nil,
+// before and/or after the node's children, using a Cursor describing
+// the current node and providing operations on it.
+//
+// The return value of ApplyFunc controls the syntax tree traversal.
+// See Apply for details.
+type ApplyFunc func(*Cursor) bool
+
+// Apply traverses a syntax tree recursively, starting with root,
+// and calling pre and post for each node as described below.
+// Apply returns the syntax tree, possibly modified.
+//
+// If pre is not nil, it is called for each node before the node's
+// children are traversed (pre-order). If pre returns false, no
+// children are traversed, and post is not called for that node.
+//
+// If post is not nil, and a prior call of pre didn't return false,
+// post is called for each node after its children are traversed
+// (post-order). If post returns false, traversal is terminated and
+// Apply returns immediately.
+//
+// Only fields that refer to AST nodes are considered children;
+// i.e., token.Pos, Scopes, Objects, and fields of basic types
+// (strings, etc.) are ignored.
+//
+// Children are traversed in the order in which they appear in the
+// respective node's struct definition. A package's files are
+// traversed in the filenames' alphabetical order.
+//
+func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
+ parent := &struct{ ast.Node }{root}
+ defer func() {
+ if r := recover(); r != nil && r != abort {
+ panic(r)
+ }
+ result = parent.Node
+ }()
+ a := &application{pre: pre, post: post}
+ a.apply(parent, "Node", nil, root)
+ return
+}
+
+var abort = new(int) // singleton, to signal termination of Apply
+
+// A Cursor describes a node encountered during Apply.
+// Information about the node and its parent is available
+// from the Node, Parent, Name, and Index methods.
+//
+// If p is a variable of type and value of the current parent node
+// c.Parent(), and f is the field identifier with name c.Name(),
+// the following invariants hold:
+//
+// p.f == c.Node() if c.Index() < 0
+// p.f[c.Index()] == c.Node() if c.Index() >= 0
+//
+// The methods Replace, Delete, InsertBefore, and InsertAfter
+// can be used to change the AST without disrupting Apply.
+type Cursor struct {
+ parent ast.Node
+ name string
+ iter *iterator // valid if non-nil
+ node ast.Node
+}
+
+// Node returns the current Node.
+func (c *Cursor) Node() ast.Node { return c.node }
+
+// Parent returns the parent of the current Node.
+func (c *Cursor) Parent() ast.Node { return c.parent }
+
+// Name returns the name of the parent Node field that contains the current Node.
+// If the parent is a *ast.Package and the current Node is a *ast.File, Name returns
+// the filename for the current Node.
+func (c *Cursor) Name() string { return c.name }
+
+// Index reports the index >= 0 of the current Node in the slice of Nodes that
+// contains it, or a value < 0 if the current Node is not part of a slice.
+// The index of the current node changes if InsertBefore is called while
+// processing the current node.
+func (c *Cursor) Index() int {
+ if c.iter != nil {
+ return c.iter.index
+ }
+ return -1
+}
+
+// field returns the current node's parent field value.
+func (c *Cursor) field() reflect.Value {
+ return reflect.Indirect(reflect.ValueOf(c.parent)).FieldByName(c.name)
+}
+
+// Replace replaces the current Node with n.
+// The replacement node is not walked by Apply.
+func (c *Cursor) Replace(n ast.Node) {
+ if _, ok := c.node.(*ast.File); ok {
+ file, ok := n.(*ast.File)
+ if !ok {
+ panic("attempt to replace *ast.File with non-*ast.File")
+ }
+ c.parent.(*ast.Package).Files[c.name] = file
+ return
+ }
+
+ v := c.field()
+ if i := c.Index(); i >= 0 {
+ v = v.Index(i)
+ }
+ v.Set(reflect.ValueOf(n))
+}
+
+// Delete deletes the current Node from its containing slice.
+// If the current Node is not part of a slice, Delete panics.
+// As a special case, if the current node is a package file,
+// Delete removes it from the package's Files map.
+func (c *Cursor) Delete() {
+ if _, ok := c.node.(*ast.File); ok {
+ delete(c.parent.(*ast.Package).Files, c.name)
+ return
+ }
+
+ i := c.Index()
+ if i < 0 {
+ panic("Delete node not contained in slice")
+ }
+ v := c.field()
+ l := v.Len()
+ reflect.Copy(v.Slice(i, l), v.Slice(i+1, l))
+ v.Index(l - 1).Set(reflect.Zero(v.Type().Elem()))
+ v.SetLen(l - 1)
+ c.iter.step--
+}
+
+// InsertAfter inserts n after the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertAfter panics.
+// Apply does not walk n.
+func (c *Cursor) InsertAfter(n ast.Node) {
+ i := c.Index()
+ if i < 0 {
+ panic("InsertAfter node not contained in slice")
+ }
+ v := c.field()
+ v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+ l := v.Len()
+ reflect.Copy(v.Slice(i+2, l), v.Slice(i+1, l))
+ v.Index(i + 1).Set(reflect.ValueOf(n))
+ c.iter.step++
+}
+
+// InsertBefore inserts n before the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertBefore panics.
+// Apply will not walk n.
+func (c *Cursor) InsertBefore(n ast.Node) {
+ i := c.Index()
+ if i < 0 {
+ panic("InsertBefore node not contained in slice")
+ }
+ v := c.field()
+ v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+ l := v.Len()
+ reflect.Copy(v.Slice(i+1, l), v.Slice(i, l))
+ v.Index(i).Set(reflect.ValueOf(n))
+ c.iter.index++
+}
+
+// application carries all the shared data so we can pass it around cheaply.
+type application struct {
+ pre, post ApplyFunc
+ cursor Cursor
+ iter iterator
+}
+
+func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.Node) {
+ // convert typed nil into untyped nil
+ if v := reflect.ValueOf(n); v.Kind() == reflect.Ptr && v.IsNil() {
+ n = nil
+ }
+
+ // avoid heap-allocating a new cursor for each apply call; reuse a.cursor instead
+ saved := a.cursor
+ a.cursor.parent = parent
+ a.cursor.name = name
+ a.cursor.iter = iter
+ a.cursor.node = n
+
+ if a.pre != nil && !a.pre(&a.cursor) {
+ a.cursor = saved
+ return
+ }
+
+ // walk children
+ // (the order of the cases matches the order of the corresponding node types in go/ast)
+ switch n := n.(type) {
+ case nil:
+ // nothing to do
+
+ // Comments and fields
+ case *ast.Comment:
+ // nothing to do
+
+ case *ast.CommentGroup:
+ if n != nil {
+ a.applyList(n, "List")
+ }
+
+ case *ast.Field:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.applyList(n, "Names")
+ a.apply(n, "Type", nil, n.Type)
+ a.apply(n, "Tag", nil, n.Tag)
+ a.apply(n, "Comment", nil, n.Comment)
+
+ case *ast.FieldList:
+ a.applyList(n, "List")
+
+ // Expressions
+ case *ast.BadExpr, *ast.Ident, *ast.BasicLit:
+ // nothing to do
+
+ case *ast.Ellipsis:
+ a.apply(n, "Elt", nil, n.Elt)
+
+ case *ast.FuncLit:
+ a.apply(n, "Type", nil, n.Type)
+ a.apply(n, "Body", nil, n.Body)
+
+ case *ast.CompositeLit:
+ a.apply(n, "Type", nil, n.Type)
+ a.applyList(n, "Elts")
+
+ case *ast.ParenExpr:
+ a.apply(n, "X", nil, n.X)
+
+ case *ast.SelectorExpr:
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Sel", nil, n.Sel)
+
+ case *ast.IndexExpr:
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Index", nil, n.Index)
+
+ case *ast.SliceExpr:
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Low", nil, n.Low)
+ a.apply(n, "High", nil, n.High)
+ a.apply(n, "Max", nil, n.Max)
+
+ case *ast.TypeAssertExpr:
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Type", nil, n.Type)
+
+ case *ast.CallExpr:
+ a.apply(n, "Fun", nil, n.Fun)
+ a.applyList(n, "Args")
+
+ case *ast.StarExpr:
+ a.apply(n, "X", nil, n.X)
+
+ case *ast.UnaryExpr:
+ a.apply(n, "X", nil, n.X)
+
+ case *ast.BinaryExpr:
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Y", nil, n.Y)
+
+ case *ast.KeyValueExpr:
+ a.apply(n, "Key", nil, n.Key)
+ a.apply(n, "Value", nil, n.Value)
+
+ // Types
+ case *ast.ArrayType:
+ a.apply(n, "Len", nil, n.Len)
+ a.apply(n, "Elt", nil, n.Elt)
+
+ case *ast.StructType:
+ a.apply(n, "Fields", nil, n.Fields)
+
+ case *ast.FuncType:
+ a.apply(n, "Params", nil, n.Params)
+ a.apply(n, "Results", nil, n.Results)
+
+ case *ast.InterfaceType:
+ a.apply(n, "Methods", nil, n.Methods)
+
+ case *ast.MapType:
+ a.apply(n, "Key", nil, n.Key)
+ a.apply(n, "Value", nil, n.Value)
+
+ case *ast.ChanType:
+ a.apply(n, "Value", nil, n.Value)
+
+ // Statements
+ case *ast.BadStmt:
+ // nothing to do
+
+ case *ast.DeclStmt:
+ a.apply(n, "Decl", nil, n.Decl)
+
+ case *ast.EmptyStmt:
+ // nothing to do
+
+ case *ast.LabeledStmt:
+ a.apply(n, "Label", nil, n.Label)
+ a.apply(n, "Stmt", nil, n.Stmt)
+
+ case *ast.ExprStmt:
+ a.apply(n, "X", nil, n.X)
+
+ case *ast.SendStmt:
+ a.apply(n, "Chan", nil, n.Chan)
+ a.apply(n, "Value", nil, n.Value)
+
+ case *ast.IncDecStmt:
+ a.apply(n, "X", nil, n.X)
+
+ case *ast.AssignStmt:
+ a.applyList(n, "Lhs")
+ a.applyList(n, "Rhs")
+
+ case *ast.GoStmt:
+ a.apply(n, "Call", nil, n.Call)
+
+ case *ast.DeferStmt:
+ a.apply(n, "Call", nil, n.Call)
+
+ case *ast.ReturnStmt:
+ a.applyList(n, "Results")
+
+ case *ast.BranchStmt:
+ a.apply(n, "Label", nil, n.Label)
+
+ case *ast.BlockStmt:
+ a.applyList(n, "List")
+
+ case *ast.IfStmt:
+ a.apply(n, "Init", nil, n.Init)
+ a.apply(n, "Cond", nil, n.Cond)
+ a.apply(n, "Body", nil, n.Body)
+ a.apply(n, "Else", nil, n.Else)
+
+ case *ast.CaseClause:
+ a.applyList(n, "List")
+ a.applyList(n, "Body")
+
+ case *ast.SwitchStmt:
+ a.apply(n, "Init", nil, n.Init)
+ a.apply(n, "Tag", nil, n.Tag)
+ a.apply(n, "Body", nil, n.Body)
+
+ case *ast.TypeSwitchStmt:
+ a.apply(n, "Init", nil, n.Init)
+ a.apply(n, "Assign", nil, n.Assign)
+ a.apply(n, "Body", nil, n.Body)
+
+ case *ast.CommClause:
+ a.apply(n, "Comm", nil, n.Comm)
+ a.applyList(n, "Body")
+
+ case *ast.SelectStmt:
+ a.apply(n, "Body", nil, n.Body)
+
+ case *ast.ForStmt:
+ a.apply(n, "Init", nil, n.Init)
+ a.apply(n, "Cond", nil, n.Cond)
+ a.apply(n, "Post", nil, n.Post)
+ a.apply(n, "Body", nil, n.Body)
+
+ case *ast.RangeStmt:
+ a.apply(n, "Key", nil, n.Key)
+ a.apply(n, "Value", nil, n.Value)
+ a.apply(n, "X", nil, n.X)
+ a.apply(n, "Body", nil, n.Body)
+
+ // Declarations
+ case *ast.ImportSpec:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.apply(n, "Name", nil, n.Name)
+ a.apply(n, "Path", nil, n.Path)
+ a.apply(n, "Comment", nil, n.Comment)
+
+ case *ast.ValueSpec:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.applyList(n, "Names")
+ a.apply(n, "Type", nil, n.Type)
+ a.applyList(n, "Values")
+ a.apply(n, "Comment", nil, n.Comment)
+
+ case *ast.TypeSpec:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.apply(n, "Name", nil, n.Name)
+ a.apply(n, "Type", nil, n.Type)
+ a.apply(n, "Comment", nil, n.Comment)
+
+ case *ast.BadDecl:
+ // nothing to do
+
+ case *ast.GenDecl:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.applyList(n, "Specs")
+
+ case *ast.FuncDecl:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.apply(n, "Recv", nil, n.Recv)
+ a.apply(n, "Name", nil, n.Name)
+ a.apply(n, "Type", nil, n.Type)
+ a.apply(n, "Body", nil, n.Body)
+
+ // Files and packages
+ case *ast.File:
+ a.apply(n, "Doc", nil, n.Doc)
+ a.apply(n, "Name", nil, n.Name)
+ a.applyList(n, "Decls")
+ // Don't walk n.Comments; they have either been walked already if
+ // they are Doc comments, or they can be easily walked explicitly.
+
+ case *ast.Package:
+ // collect and sort names for reproducible behavior
+ var names []string
+ for name := range n.Files {
+ names = append(names, name)
+ }
+ sort.Strings(names)
+ for _, name := range names {
+ a.apply(n, name, nil, n.Files[name])
+ }
+
+ default:
+ panic(fmt.Sprintf("Apply: unexpected node type %T", n))
+ }
+
+ if a.post != nil && !a.post(&a.cursor) {
+ panic(abort)
+ }
+
+ a.cursor = saved
+}
+
+// An iterator controls iteration over a slice of nodes.
+type iterator struct {
+ index, step int
+}
+
+func (a *application) applyList(parent ast.Node, name string) {
+ // avoid heap-allocating a new iterator for each applyList call; reuse a.iter instead
+ saved := a.iter
+ a.iter.index = 0
+ for {
+ // must reload parent.name each time, since cursor modifications might change it
+ v := reflect.Indirect(reflect.ValueOf(parent)).FieldByName(name)
+ if a.iter.index >= v.Len() {
+ break
+ }
+
+ // element x may be nil in a bad AST - be cautious
+ var x ast.Node
+ if e := v.Index(a.iter.index); e.IsValid() {
+ x = e.Interface().(ast.Node)
+ }
+
+ a.iter.step = 1
+ a.apply(parent, name, &a.iter, x)
+ a.iter.index += a.iter.step
+ }
+ a.iter = saved
+}
--- /dev/null
+package astutil
+
+import "go/ast"
+
+// Unparen returns e with any enclosing parentheses stripped.
+func Unparen(e ast.Expr) ast.Expr {
+ for {
+ p, ok := e.(*ast.ParenExpr)
+ if !ok {
+ return e
+ }
+ e = p.X
+ }
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package inspector provides helper functions for traversal over the
+// syntax trees of a package, including node filtering by type, and
+// materialization of the traversal stack.
+//
+// During construction, the inspector does a complete traversal and
+// builds a list of push/pop events and their node type. Subsequent
+// method calls that request a traversal scan this list, rather than walk
+// the AST, and perform type filtering using efficient bit sets.
+//
+// Experiments suggest the inspector's traversals are about 2.5x faster
+// than ast.Inspect, but it may take around 5 traversals for this
+// benefit to amortize the inspector's construction cost.
+// If efficiency is the primary concern, do not use use Inspector for
+// one-off traversals.
+package inspector
+
+// There are four orthogonal features in a traversal:
+// 1 type filtering
+// 2 pruning
+// 3 postorder calls to f
+// 4 stack
+// Rather than offer all of them in the API,
+// only a few combinations are exposed:
+// - Preorder is the fastest and has fewest features,
+// but is the most commonly needed traversal.
+// - Nodes and WithStack both provide pruning and postorder calls,
+// even though few clients need it, because supporting two versions
+// is not justified.
+// More combinations could be supported by expressing them as
+// wrappers around a more generic traversal, but this was measured
+// and found to degrade performance significantly (30%).
+
+import (
+ "go/ast"
+)
+
+// An Inspector provides methods for inspecting
+// (traversing) the syntax trees of a package.
+type Inspector struct {
+ events []event
+}
+
+// New returns an Inspector for the specified syntax trees.
+func New(files []*ast.File) *Inspector {
+ return &Inspector{traverse(files)}
+}
+
+// An event represents a push or a pop
+// of an ast.Node during a traversal.
+type event struct {
+ node ast.Node
+ typ uint64 // typeOf(node)
+ index int // 1 + index of corresponding pop event, or 0 if this is a pop
+}
+
+// Preorder visits all the nodes of the files supplied to New in
+// depth-first order. It calls f(n) for each node n before it visits
+// n's children.
+//
+// The types argument, if non-empty, enables type-based filtering of
+// events. The function f if is called only for nodes whose type
+// matches an element of the types slice.
+func (in *Inspector) Preorder(types []ast.Node, f func(ast.Node)) {
+ // Because it avoids postorder calls to f, and the pruning
+ // check, Preorder is almost twice as fast as Nodes. The two
+ // features seem to contribute similar slowdowns (~1.4x each).
+
+ mask := maskOf(types)
+ for i := 0; i < len(in.events); {
+ ev := in.events[i]
+ if ev.typ&mask != 0 {
+ if ev.index > 0 {
+ f(ev.node)
+ }
+ }
+ i++
+ }
+}
+
+// Nodes visits the nodes of the files supplied to New in depth-first
+// order. It calls f(n, true) for each node n before it visits n's
+// children. If f returns true, Nodes invokes f recursively for each
+// of the non-nil children of the node, followed by a call of
+// f(n, false).
+//
+// The types argument, if non-empty, enables type-based filtering of
+// events. The function f if is called only for nodes whose type
+// matches an element of the types slice.
+func (in *Inspector) Nodes(types []ast.Node, f func(n ast.Node, push bool) (prune bool)) {
+ mask := maskOf(types)
+ for i := 0; i < len(in.events); {
+ ev := in.events[i]
+ if ev.typ&mask != 0 {
+ if ev.index > 0 {
+ // push
+ if !f(ev.node, true) {
+ i = ev.index // jump to corresponding pop + 1
+ continue
+ }
+ } else {
+ // pop
+ f(ev.node, false)
+ }
+ }
+ i++
+ }
+}
+
+// WithStack visits nodes in a similar manner to Nodes, but it
+// supplies each call to f an additional argument, the current
+// traversal stack. The stack's first element is the outermost node,
+// an *ast.File; its last is the innermost, n.
+func (in *Inspector) WithStack(types []ast.Node, f func(n ast.Node, push bool, stack []ast.Node) (prune bool)) {
+ mask := maskOf(types)
+ var stack []ast.Node
+ for i := 0; i < len(in.events); {
+ ev := in.events[i]
+ if ev.index > 0 {
+ // push
+ stack = append(stack, ev.node)
+ if ev.typ&mask != 0 {
+ if !f(ev.node, true, stack) {
+ i = ev.index
+ stack = stack[:len(stack)-1]
+ continue
+ }
+ }
+ } else {
+ // pop
+ if ev.typ&mask != 0 {
+ f(ev.node, false, stack)
+ }
+ stack = stack[:len(stack)-1]
+ }
+ i++
+ }
+}
+
+// traverse builds the table of events representing a traversal.
+func traverse(files []*ast.File) []event {
+ // Preallocate approximate number of events
+ // based on source file extent.
+ // This makes traverse faster by 4x (!).
+ var extent int
+ for _, f := range files {
+ extent += int(f.End() - f.Pos())
+ }
+ // This estimate is based on the net/http package.
+ events := make([]event, 0, extent*33/100)
+
+ var stack []event
+ for _, f := range files {
+ ast.Inspect(f, func(n ast.Node) bool {
+ if n != nil {
+ // push
+ ev := event{
+ node: n,
+ typ: typeOf(n),
+ index: len(events), // push event temporarily holds own index
+ }
+ stack = append(stack, ev)
+ events = append(events, ev)
+ } else {
+ // pop
+ ev := stack[len(stack)-1]
+ stack = stack[:len(stack)-1]
+
+ events[ev.index].index = len(events) + 1 // make push refer to pop
+
+ ev.index = 0 // turn ev into a pop event
+ events = append(events, ev)
+ }
+ return true
+ })
+ }
+
+ return events
+}
--- /dev/null
+package inspector
+
+// This file defines func typeOf(ast.Node) uint64.
+//
+// The initial map-based implementation was too slow;
+// see https://go-review.googlesource.com/c/tools/+/135655/1/go/ast/inspector/inspector.go#196
+
+import "go/ast"
+
+const (
+ nArrayType = iota
+ nAssignStmt
+ nBadDecl
+ nBadExpr
+ nBadStmt
+ nBasicLit
+ nBinaryExpr
+ nBlockStmt
+ nBranchStmt
+ nCallExpr
+ nCaseClause
+ nChanType
+ nCommClause
+ nComment
+ nCommentGroup
+ nCompositeLit
+ nDeclStmt
+ nDeferStmt
+ nEllipsis
+ nEmptyStmt
+ nExprStmt
+ nField
+ nFieldList
+ nFile
+ nForStmt
+ nFuncDecl
+ nFuncLit
+ nFuncType
+ nGenDecl
+ nGoStmt
+ nIdent
+ nIfStmt
+ nImportSpec
+ nIncDecStmt
+ nIndexExpr
+ nInterfaceType
+ nKeyValueExpr
+ nLabeledStmt
+ nMapType
+ nPackage
+ nParenExpr
+ nRangeStmt
+ nReturnStmt
+ nSelectStmt
+ nSelectorExpr
+ nSendStmt
+ nSliceExpr
+ nStarExpr
+ nStructType
+ nSwitchStmt
+ nTypeAssertExpr
+ nTypeSpec
+ nTypeSwitchStmt
+ nUnaryExpr
+ nValueSpec
+)
+
+// typeOf returns a distinct single-bit value that represents the type of n.
+//
+// Various implementations were benchmarked with BenchmarkNewInspector:
+// GOGC=off
+// - type switch 4.9-5.5ms 2.1ms
+// - binary search over a sorted list of types 5.5-5.9ms 2.5ms
+// - linear scan, frequency-ordered list 5.9-6.1ms 2.7ms
+// - linear scan, unordered list 6.4ms 2.7ms
+// - hash table 6.5ms 3.1ms
+// A perfect hash seemed like overkill.
+//
+// The compiler's switch statement is the clear winner
+// as it produces a binary tree in code,
+// with constant conditions and good branch prediction.
+// (Sadly it is the most verbose in source code.)
+// Binary search suffered from poor branch prediction.
+//
+func typeOf(n ast.Node) uint64 {
+ // Fast path: nearly half of all nodes are identifiers.
+ if _, ok := n.(*ast.Ident); ok {
+ return 1 << nIdent
+ }
+
+ // These cases include all nodes encountered by ast.Inspect.
+ switch n.(type) {
+ case *ast.ArrayType:
+ return 1 << nArrayType
+ case *ast.AssignStmt:
+ return 1 << nAssignStmt
+ case *ast.BadDecl:
+ return 1 << nBadDecl
+ case *ast.BadExpr:
+ return 1 << nBadExpr
+ case *ast.BadStmt:
+ return 1 << nBadStmt
+ case *ast.BasicLit:
+ return 1 << nBasicLit
+ case *ast.BinaryExpr:
+ return 1 << nBinaryExpr
+ case *ast.BlockStmt:
+ return 1 << nBlockStmt
+ case *ast.BranchStmt:
+ return 1 << nBranchStmt
+ case *ast.CallExpr:
+ return 1 << nCallExpr
+ case *ast.CaseClause:
+ return 1 << nCaseClause
+ case *ast.ChanType:
+ return 1 << nChanType
+ case *ast.CommClause:
+ return 1 << nCommClause
+ case *ast.Comment:
+ return 1 << nComment
+ case *ast.CommentGroup:
+ return 1 << nCommentGroup
+ case *ast.CompositeLit:
+ return 1 << nCompositeLit
+ case *ast.DeclStmt:
+ return 1 << nDeclStmt
+ case *ast.DeferStmt:
+ return 1 << nDeferStmt
+ case *ast.Ellipsis:
+ return 1 << nEllipsis
+ case *ast.EmptyStmt:
+ return 1 << nEmptyStmt
+ case *ast.ExprStmt:
+ return 1 << nExprStmt
+ case *ast.Field:
+ return 1 << nField
+ case *ast.FieldList:
+ return 1 << nFieldList
+ case *ast.File:
+ return 1 << nFile
+ case *ast.ForStmt:
+ return 1 << nForStmt
+ case *ast.FuncDecl:
+ return 1 << nFuncDecl
+ case *ast.FuncLit:
+ return 1 << nFuncLit
+ case *ast.FuncType:
+ return 1 << nFuncType
+ case *ast.GenDecl:
+ return 1 << nGenDecl
+ case *ast.GoStmt:
+ return 1 << nGoStmt
+ case *ast.Ident:
+ return 1 << nIdent
+ case *ast.IfStmt:
+ return 1 << nIfStmt
+ case *ast.ImportSpec:
+ return 1 << nImportSpec
+ case *ast.IncDecStmt:
+ return 1 << nIncDecStmt
+ case *ast.IndexExpr:
+ return 1 << nIndexExpr
+ case *ast.InterfaceType:
+ return 1 << nInterfaceType
+ case *ast.KeyValueExpr:
+ return 1 << nKeyValueExpr
+ case *ast.LabeledStmt:
+ return 1 << nLabeledStmt
+ case *ast.MapType:
+ return 1 << nMapType
+ case *ast.Package:
+ return 1 << nPackage
+ case *ast.ParenExpr:
+ return 1 << nParenExpr
+ case *ast.RangeStmt:
+ return 1 << nRangeStmt
+ case *ast.ReturnStmt:
+ return 1 << nReturnStmt
+ case *ast.SelectStmt:
+ return 1 << nSelectStmt
+ case *ast.SelectorExpr:
+ return 1 << nSelectorExpr
+ case *ast.SendStmt:
+ return 1 << nSendStmt
+ case *ast.SliceExpr:
+ return 1 << nSliceExpr
+ case *ast.StarExpr:
+ return 1 << nStarExpr
+ case *ast.StructType:
+ return 1 << nStructType
+ case *ast.SwitchStmt:
+ return 1 << nSwitchStmt
+ case *ast.TypeAssertExpr:
+ return 1 << nTypeAssertExpr
+ case *ast.TypeSpec:
+ return 1 << nTypeSpec
+ case *ast.TypeSwitchStmt:
+ return 1 << nTypeSwitchStmt
+ case *ast.UnaryExpr:
+ return 1 << nUnaryExpr
+ case *ast.ValueSpec:
+ return 1 << nValueSpec
+ }
+ return 0
+}
+
+func maskOf(nodes []ast.Node) uint64 {
+ if nodes == nil {
+ return 1<<64 - 1 // match all node types
+ }
+ var mask uint64
+ for _, n := range nodes {
+ mask |= typeOf(n)
+ }
+ return mask
+}
--- /dev/null
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cfg
+
+// This file implements the CFG construction pass.
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+)
+
+type builder struct {
+ cfg *CFG
+ mayReturn func(*ast.CallExpr) bool
+ current *Block
+ lblocks map[*ast.Object]*lblock // labeled blocks
+ targets *targets // linked stack of branch targets
+}
+
+func (b *builder) stmt(_s ast.Stmt) {
+ // The label of the current statement. If non-nil, its _goto
+ // target is always set; its _break and _continue are set only
+ // within the body of switch/typeswitch/select/for/range.
+ // It is effectively an additional default-nil parameter of stmt().
+ var label *lblock
+start:
+ switch s := _s.(type) {
+ case *ast.BadStmt,
+ *ast.SendStmt,
+ *ast.IncDecStmt,
+ *ast.GoStmt,
+ *ast.DeferStmt,
+ *ast.EmptyStmt,
+ *ast.AssignStmt:
+ // No effect on control flow.
+ b.add(s)
+
+ case *ast.ExprStmt:
+ b.add(s)
+ if call, ok := s.X.(*ast.CallExpr); ok && !b.mayReturn(call) {
+ // Calls to panic, os.Exit, etc, never return.
+ b.current = b.newBlock("unreachable.call")
+ }
+
+ case *ast.DeclStmt:
+ // Treat each var ValueSpec as a separate statement.
+ d := s.Decl.(*ast.GenDecl)
+ if d.Tok == token.VAR {
+ for _, spec := range d.Specs {
+ if spec, ok := spec.(*ast.ValueSpec); ok {
+ b.add(spec)
+ }
+ }
+ }
+
+ case *ast.LabeledStmt:
+ label = b.labeledBlock(s.Label)
+ b.jump(label._goto)
+ b.current = label._goto
+ _s = s.Stmt
+ goto start // effectively: tailcall stmt(g, s.Stmt, label)
+
+ case *ast.ReturnStmt:
+ b.add(s)
+ b.current = b.newBlock("unreachable.return")
+
+ case *ast.BranchStmt:
+ b.branchStmt(s)
+
+ case *ast.BlockStmt:
+ b.stmtList(s.List)
+
+ case *ast.IfStmt:
+ if s.Init != nil {
+ b.stmt(s.Init)
+ }
+ then := b.newBlock("if.then")
+ done := b.newBlock("if.done")
+ _else := done
+ if s.Else != nil {
+ _else = b.newBlock("if.else")
+ }
+ b.add(s.Cond)
+ b.ifelse(then, _else)
+ b.current = then
+ b.stmt(s.Body)
+ b.jump(done)
+
+ if s.Else != nil {
+ b.current = _else
+ b.stmt(s.Else)
+ b.jump(done)
+ }
+
+ b.current = done
+
+ case *ast.SwitchStmt:
+ b.switchStmt(s, label)
+
+ case *ast.TypeSwitchStmt:
+ b.typeSwitchStmt(s, label)
+
+ case *ast.SelectStmt:
+ b.selectStmt(s, label)
+
+ case *ast.ForStmt:
+ b.forStmt(s, label)
+
+ case *ast.RangeStmt:
+ b.rangeStmt(s, label)
+
+ default:
+ panic(fmt.Sprintf("unexpected statement kind: %T", s))
+ }
+}
+
+func (b *builder) stmtList(list []ast.Stmt) {
+ for _, s := range list {
+ b.stmt(s)
+ }
+}
+
+func (b *builder) branchStmt(s *ast.BranchStmt) {
+ var block *Block
+ switch s.Tok {
+ case token.BREAK:
+ if s.Label != nil {
+ if lb := b.labeledBlock(s.Label); lb != nil {
+ block = lb._break
+ }
+ } else {
+ for t := b.targets; t != nil && block == nil; t = t.tail {
+ block = t._break
+ }
+ }
+
+ case token.CONTINUE:
+ if s.Label != nil {
+ if lb := b.labeledBlock(s.Label); lb != nil {
+ block = lb._continue
+ }
+ } else {
+ for t := b.targets; t != nil && block == nil; t = t.tail {
+ block = t._continue
+ }
+ }
+
+ case token.FALLTHROUGH:
+ for t := b.targets; t != nil; t = t.tail {
+ block = t._fallthrough
+ }
+
+ case token.GOTO:
+ if s.Label != nil {
+ block = b.labeledBlock(s.Label)._goto
+ }
+ }
+ if block == nil {
+ block = b.newBlock("undefined.branch")
+ }
+ b.jump(block)
+ b.current = b.newBlock("unreachable.branch")
+}
+
+func (b *builder) switchStmt(s *ast.SwitchStmt, label *lblock) {
+ if s.Init != nil {
+ b.stmt(s.Init)
+ }
+ if s.Tag != nil {
+ b.add(s.Tag)
+ }
+ done := b.newBlock("switch.done")
+ if label != nil {
+ label._break = done
+ }
+ // We pull the default case (if present) down to the end.
+ // But each fallthrough label must point to the next
+ // body block in source order, so we preallocate a
+ // body block (fallthru) for the next case.
+ // Unfortunately this makes for a confusing block order.
+ var defaultBody *[]ast.Stmt
+ var defaultFallthrough *Block
+ var fallthru, defaultBlock *Block
+ ncases := len(s.Body.List)
+ for i, clause := range s.Body.List {
+ body := fallthru
+ if body == nil {
+ body = b.newBlock("switch.body") // first case only
+ }
+
+ // Preallocate body block for the next case.
+ fallthru = done
+ if i+1 < ncases {
+ fallthru = b.newBlock("switch.body")
+ }
+
+ cc := clause.(*ast.CaseClause)
+ if cc.List == nil {
+ // Default case.
+ defaultBody = &cc.Body
+ defaultFallthrough = fallthru
+ defaultBlock = body
+ continue
+ }
+
+ var nextCond *Block
+ for _, cond := range cc.List {
+ nextCond = b.newBlock("switch.next")
+ b.add(cond) // one half of the tag==cond condition
+ b.ifelse(body, nextCond)
+ b.current = nextCond
+ }
+ b.current = body
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ _fallthrough: fallthru,
+ }
+ b.stmtList(cc.Body)
+ b.targets = b.targets.tail
+ b.jump(done)
+ b.current = nextCond
+ }
+ if defaultBlock != nil {
+ b.jump(defaultBlock)
+ b.current = defaultBlock
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ _fallthrough: defaultFallthrough,
+ }
+ b.stmtList(*defaultBody)
+ b.targets = b.targets.tail
+ }
+ b.jump(done)
+ b.current = done
+}
+
+func (b *builder) typeSwitchStmt(s *ast.TypeSwitchStmt, label *lblock) {
+ if s.Init != nil {
+ b.stmt(s.Init)
+ }
+ if s.Assign != nil {
+ b.add(s.Assign)
+ }
+
+ done := b.newBlock("typeswitch.done")
+ if label != nil {
+ label._break = done
+ }
+ var default_ *ast.CaseClause
+ for _, clause := range s.Body.List {
+ cc := clause.(*ast.CaseClause)
+ if cc.List == nil {
+ default_ = cc
+ continue
+ }
+ body := b.newBlock("typeswitch.body")
+ var next *Block
+ for _, casetype := range cc.List {
+ next = b.newBlock("typeswitch.next")
+ // casetype is a type, so don't call b.add(casetype).
+ // This block logically contains a type assertion,
+ // x.(casetype), but it's unclear how to represent x.
+ _ = casetype
+ b.ifelse(body, next)
+ b.current = next
+ }
+ b.current = body
+ b.typeCaseBody(cc, done)
+ b.current = next
+ }
+ if default_ != nil {
+ b.typeCaseBody(default_, done)
+ } else {
+ b.jump(done)
+ }
+ b.current = done
+}
+
+func (b *builder) typeCaseBody(cc *ast.CaseClause, done *Block) {
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ }
+ b.stmtList(cc.Body)
+ b.targets = b.targets.tail
+ b.jump(done)
+}
+
+func (b *builder) selectStmt(s *ast.SelectStmt, label *lblock) {
+ // First evaluate channel expressions.
+ // TODO(adonovan): fix: evaluate only channel exprs here.
+ for _, clause := range s.Body.List {
+ if comm := clause.(*ast.CommClause).Comm; comm != nil {
+ b.stmt(comm)
+ }
+ }
+
+ done := b.newBlock("select.done")
+ if label != nil {
+ label._break = done
+ }
+
+ var defaultBody *[]ast.Stmt
+ for _, cc := range s.Body.List {
+ clause := cc.(*ast.CommClause)
+ if clause.Comm == nil {
+ defaultBody = &clause.Body
+ continue
+ }
+ body := b.newBlock("select.body")
+ next := b.newBlock("select.next")
+ b.ifelse(body, next)
+ b.current = body
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ }
+ switch comm := clause.Comm.(type) {
+ case *ast.ExprStmt: // <-ch
+ // nop
+ case *ast.AssignStmt: // x := <-states[state].Chan
+ b.add(comm.Lhs[0])
+ }
+ b.stmtList(clause.Body)
+ b.targets = b.targets.tail
+ b.jump(done)
+ b.current = next
+ }
+ if defaultBody != nil {
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ }
+ b.stmtList(*defaultBody)
+ b.targets = b.targets.tail
+ b.jump(done)
+ }
+ b.current = done
+}
+
+func (b *builder) forStmt(s *ast.ForStmt, label *lblock) {
+ // ...init...
+ // jump loop
+ // loop:
+ // if cond goto body else done
+ // body:
+ // ...body...
+ // jump post
+ // post: (target of continue)
+ // ...post...
+ // jump loop
+ // done: (target of break)
+ if s.Init != nil {
+ b.stmt(s.Init)
+ }
+ body := b.newBlock("for.body")
+ done := b.newBlock("for.done") // target of 'break'
+ loop := body // target of back-edge
+ if s.Cond != nil {
+ loop = b.newBlock("for.loop")
+ }
+ cont := loop // target of 'continue'
+ if s.Post != nil {
+ cont = b.newBlock("for.post")
+ }
+ if label != nil {
+ label._break = done
+ label._continue = cont
+ }
+ b.jump(loop)
+ b.current = loop
+ if loop != body {
+ b.add(s.Cond)
+ b.ifelse(body, done)
+ b.current = body
+ }
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ _continue: cont,
+ }
+ b.stmt(s.Body)
+ b.targets = b.targets.tail
+ b.jump(cont)
+
+ if s.Post != nil {
+ b.current = cont
+ b.stmt(s.Post)
+ b.jump(loop) // back-edge
+ }
+ b.current = done
+}
+
+func (b *builder) rangeStmt(s *ast.RangeStmt, label *lblock) {
+ b.add(s.X)
+
+ if s.Key != nil {
+ b.add(s.Key)
+ }
+ if s.Value != nil {
+ b.add(s.Value)
+ }
+
+ // ...
+ // loop: (target of continue)
+ // if ... goto body else done
+ // body:
+ // ...
+ // jump loop
+ // done: (target of break)
+
+ loop := b.newBlock("range.loop")
+ b.jump(loop)
+ b.current = loop
+
+ body := b.newBlock("range.body")
+ done := b.newBlock("range.done")
+ b.ifelse(body, done)
+ b.current = body
+
+ if label != nil {
+ label._break = done
+ label._continue = loop
+ }
+ b.targets = &targets{
+ tail: b.targets,
+ _break: done,
+ _continue: loop,
+ }
+ b.stmt(s.Body)
+ b.targets = b.targets.tail
+ b.jump(loop) // back-edge
+ b.current = done
+}
+
+// -------- helpers --------
+
+// Destinations associated with unlabeled for/switch/select stmts.
+// We push/pop one of these as we enter/leave each construct and for
+// each BranchStmt we scan for the innermost target of the right type.
+//
+type targets struct {
+ tail *targets // rest of stack
+ _break *Block
+ _continue *Block
+ _fallthrough *Block
+}
+
+// Destinations associated with a labeled block.
+// We populate these as labels are encountered in forward gotos or
+// labeled statements.
+//
+type lblock struct {
+ _goto *Block
+ _break *Block
+ _continue *Block
+}
+
+// labeledBlock returns the branch target associated with the
+// specified label, creating it if needed.
+//
+func (b *builder) labeledBlock(label *ast.Ident) *lblock {
+ lb := b.lblocks[label.Obj]
+ if lb == nil {
+ lb = &lblock{_goto: b.newBlock(label.Name)}
+ if b.lblocks == nil {
+ b.lblocks = make(map[*ast.Object]*lblock)
+ }
+ b.lblocks[label.Obj] = lb
+ }
+ return lb
+}
+
+// newBlock appends a new unconnected basic block to b.cfg's block
+// slice and returns it.
+// It does not automatically become the current block.
+// comment is an optional string for more readable debugging output.
+func (b *builder) newBlock(comment string) *Block {
+ g := b.cfg
+ block := &Block{
+ Index: int32(len(g.Blocks)),
+ comment: comment,
+ }
+ block.Succs = block.succs2[:0]
+ g.Blocks = append(g.Blocks, block)
+ return block
+}
+
+func (b *builder) add(n ast.Node) {
+ b.current.Nodes = append(b.current.Nodes, n)
+}
+
+// jump adds an edge from the current block to the target block,
+// and sets b.current to nil.
+func (b *builder) jump(target *Block) {
+ b.current.Succs = append(b.current.Succs, target)
+ b.current = nil
+}
+
+// ifelse emits edges from the current block to the t and f blocks,
+// and sets b.current to nil.
+func (b *builder) ifelse(t, f *Block) {
+ b.current.Succs = append(b.current.Succs, t, f)
+ b.current = nil
+}
--- /dev/null
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This package constructs a simple control-flow graph (CFG) of the
+// statements and expressions within a single function.
+//
+// Use cfg.New to construct the CFG for a function body.
+//
+// The blocks of the CFG contain all the function's non-control
+// statements. The CFG does not contain control statements such as If,
+// Switch, Select, and Branch, but does contain their subexpressions.
+// For example, this source code:
+//
+// if x := f(); x != nil {
+// T()
+// } else {
+// F()
+// }
+//
+// produces this CFG:
+//
+// 1: x := f()
+// x != nil
+// succs: 2, 3
+// 2: T()
+// succs: 4
+// 3: F()
+// succs: 4
+// 4:
+//
+// The CFG does contain Return statements; even implicit returns are
+// materialized (at the position of the function's closing brace).
+//
+// The CFG does not record conditions associated with conditional branch
+// edges, nor the short-circuit semantics of the && and || operators,
+// nor abnormal control flow caused by panic. If you need this
+// information, use golang.org/x/tools/go/ssa instead.
+//
+package cfg
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/format"
+ "go/token"
+)
+
+// A CFG represents the control-flow graph of a single function.
+//
+// The entry point is Blocks[0]; there may be multiple return blocks.
+type CFG struct {
+ Blocks []*Block // block[0] is entry; order otherwise undefined
+}
+
+// A Block represents a basic block: a list of statements and
+// expressions that are always evaluated sequentially.
+//
+// A block may have 0-2 successors: zero for a return block or a block
+// that calls a function such as panic that never returns; one for a
+// normal (jump) block; and two for a conditional (if) block.
+type Block struct {
+ Nodes []ast.Node // statements, expressions, and ValueSpecs
+ Succs []*Block // successor nodes in the graph
+ Index int32 // index within CFG.Blocks
+ Live bool // block is reachable from entry
+
+ comment string // for debugging
+ succs2 [2]*Block // underlying array for Succs
+}
+
+// New returns a new control-flow graph for the specified function body,
+// which must be non-nil.
+//
+// The CFG builder calls mayReturn to determine whether a given function
+// call may return. For example, calls to panic, os.Exit, and log.Fatal
+// do not return, so the builder can remove infeasible graph edges
+// following such calls. The builder calls mayReturn only for a
+// CallExpr beneath an ExprStmt.
+func New(body *ast.BlockStmt, mayReturn func(*ast.CallExpr) bool) *CFG {
+ b := builder{
+ mayReturn: mayReturn,
+ cfg: new(CFG),
+ }
+ b.current = b.newBlock("entry")
+ b.stmt(body)
+
+ // Compute liveness (reachability from entry point), breadth-first.
+ q := make([]*Block, 0, len(b.cfg.Blocks))
+ q = append(q, b.cfg.Blocks[0]) // entry point
+ for len(q) > 0 {
+ b := q[len(q)-1]
+ q = q[:len(q)-1]
+
+ if !b.Live {
+ b.Live = true
+ q = append(q, b.Succs...)
+ }
+ }
+
+ // Does control fall off the end of the function's body?
+ // Make implicit return explicit.
+ if b.current != nil && b.current.Live {
+ b.add(&ast.ReturnStmt{
+ Return: body.End() - 1,
+ })
+ }
+
+ return b.cfg
+}
+
+func (b *Block) String() string {
+ return fmt.Sprintf("block %d (%s)", b.Index, b.comment)
+}
+
+// Return returns the return statement at the end of this block if present, nil otherwise.
+func (b *Block) Return() (ret *ast.ReturnStmt) {
+ if len(b.Nodes) > 0 {
+ ret, _ = b.Nodes[len(b.Nodes)-1].(*ast.ReturnStmt)
+ }
+ return
+}
+
+// Format formats the control-flow graph for ease of debugging.
+func (g *CFG) Format(fset *token.FileSet) string {
+ var buf bytes.Buffer
+ for _, b := range g.Blocks {
+ fmt.Fprintf(&buf, ".%d: # %s\n", b.Index, b.comment)
+ for _, n := range b.Nodes {
+ fmt.Fprintf(&buf, "\t%s\n", formatNode(fset, n))
+ }
+ if len(b.Succs) > 0 {
+ fmt.Fprintf(&buf, "\tsuccs:")
+ for _, succ := range b.Succs {
+ fmt.Fprintf(&buf, " %d", succ.Index)
+ }
+ buf.WriteByte('\n')
+ }
+ buf.WriteByte('\n')
+ }
+ return buf.String()
+}
+
+func formatNode(fset *token.FileSet, n ast.Node) string {
+ var buf bytes.Buffer
+ format.Node(&buf, fset, n)
+ // Indent secondary lines by a tab.
+ return string(bytes.Replace(buf.Bytes(), []byte("\n"), []byte("\n\t"), -1))
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package objectpath defines a naming scheme for types.Objects
+// (that is, named entities in Go programs) relative to their enclosing
+// package.
+//
+// Type-checker objects are canonical, so they are usually identified by
+// their address in memory (a pointer), but a pointer has meaning only
+// within one address space. By contrast, objectpath names allow the
+// identity of an object to be sent from one program to another,
+// establishing a correspondence between types.Object variables that are
+// distinct but logically equivalent.
+//
+// A single object may have multiple paths. In this example,
+// type A struct{ X int }
+// type B A
+// the field X has two paths due to its membership of both A and B.
+// The For(obj) function always returns one of these paths, arbitrarily
+// but consistently.
+package objectpath
+
+import (
+ "fmt"
+ "strconv"
+ "strings"
+
+ "go/types"
+)
+
+// A Path is an opaque name that identifies a types.Object
+// relative to its package. Conceptually, the name consists of a
+// sequence of destructuring operations applied to the package scope
+// to obtain the original object.
+// The name does not include the package itself.
+type Path string
+
+// Encoding
+//
+// An object path is a textual and (with training) human-readable encoding
+// of a sequence of destructuring operators, starting from a types.Package.
+// The sequences represent a path through the package/object/type graph.
+// We classify these operators by their type:
+//
+// PO package->object Package.Scope.Lookup
+// OT object->type Object.Type
+// TT type->type Type.{Elem,Key,Params,Results,Underlying} [EKPRU]
+// TO type->object Type.{At,Field,Method,Obj} [AFMO]
+//
+// All valid paths start with a package and end at an object
+// and thus may be defined by the regular language:
+//
+// objectpath = PO (OT TT* TO)*
+//
+// The concrete encoding follows directly:
+// - The only PO operator is Package.Scope.Lookup, which requires an identifier.
+// - The only OT operator is Object.Type,
+// which we encode as '.' because dot cannot appear in an identifier.
+// - The TT operators are encoded as [EKPRU].
+// - The OT operators are encoded as [AFMO];
+// three of these (At,Field,Method) require an integer operand,
+// which is encoded as a string of decimal digits.
+// These indices are stable across different representations
+// of the same package, even source and export data.
+//
+// In the example below,
+//
+// package p
+//
+// type T interface {
+// f() (a string, b struct{ X int })
+// }
+//
+// field X has the path "T.UM0.RA1.F0",
+// representing the following sequence of operations:
+//
+// p.Lookup("T") T
+// .Type().Underlying().Method(0). f
+// .Type().Results().At(1) b
+// .Type().Field(0) X
+//
+// The encoding is not maximally compact---every R or P is
+// followed by an A, for example---but this simplifies the
+// encoder and decoder.
+//
+const (
+ // object->type operators
+ opType = '.' // .Type() (Object)
+
+ // type->type operators
+ opElem = 'E' // .Elem() (Pointer, Slice, Array, Chan, Map)
+ opKey = 'K' // .Key() (Map)
+ opParams = 'P' // .Params() (Signature)
+ opResults = 'R' // .Results() (Signature)
+ opUnderlying = 'U' // .Underlying() (Named)
+
+ // type->object operators
+ opAt = 'A' // .At(i) (Tuple)
+ opField = 'F' // .Field(i) (Struct)
+ opMethod = 'M' // .Method(i) (Named or Interface; not Struct: "promoted" names are ignored)
+ opObj = 'O' // .Obj() (Named)
+)
+
+// The For function returns the path to an object relative to its package,
+// or an error if the object is not accessible from the package's Scope.
+//
+// The For function guarantees to return a path only for the following objects:
+// - package-level types
+// - exported package-level non-types
+// - methods
+// - parameter and result variables
+// - struct fields
+// These objects are sufficient to define the API of their package.
+// The objects described by a package's export data are drawn from this set.
+//
+// For does not return a path for predeclared names, imported package
+// names, local names, and unexported package-level names (except
+// types).
+//
+// Example: given this definition,
+//
+// package p
+//
+// type T interface {
+// f() (a string, b struct{ X int })
+// }
+//
+// For(X) would return a path that denotes the following sequence of operations:
+//
+// p.Scope().Lookup("T") (TypeName T)
+// .Type().Underlying().Method(0). (method Func f)
+// .Type().Results().At(1) (field Var b)
+// .Type().Field(0) (field Var X)
+//
+// where p is the package (*types.Package) to which X belongs.
+func For(obj types.Object) (Path, error) {
+ pkg := obj.Pkg()
+
+ // This table lists the cases of interest.
+ //
+ // Object Action
+ // ------ ------
+ // nil reject
+ // builtin reject
+ // pkgname reject
+ // label reject
+ // var
+ // package-level accept
+ // func param/result accept
+ // local reject
+ // struct field accept
+ // const
+ // package-level accept
+ // local reject
+ // func
+ // package-level accept
+ // init functions reject
+ // concrete method accept
+ // interface method accept
+ // type
+ // package-level accept
+ // local reject
+ //
+ // The only accessible package-level objects are members of pkg itself.
+ //
+ // The cases are handled in four steps:
+ //
+ // 1. reject nil and builtin
+ // 2. accept package-level objects
+ // 3. reject obviously invalid objects
+ // 4. search the API for the path to the param/result/field/method.
+
+ // 1. reference to nil or builtin?
+ if pkg == nil {
+ return "", fmt.Errorf("predeclared %s has no path", obj)
+ }
+ scope := pkg.Scope()
+
+ // 2. package-level object?
+ if scope.Lookup(obj.Name()) == obj {
+ // Only exported objects (and non-exported types) have a path.
+ // Non-exported types may be referenced by other objects.
+ if _, ok := obj.(*types.TypeName); !ok && !obj.Exported() {
+ return "", fmt.Errorf("no path for non-exported %v", obj)
+ }
+ return Path(obj.Name()), nil
+ }
+
+ // 3. Not a package-level object.
+ // Reject obviously non-viable cases.
+ switch obj := obj.(type) {
+ case *types.Const, // Only package-level constants have a path.
+ *types.TypeName, // Only package-level types have a path.
+ *types.Label, // Labels are function-local.
+ *types.PkgName: // PkgNames are file-local.
+ return "", fmt.Errorf("no path for %v", obj)
+
+ case *types.Var:
+ // Could be:
+ // - a field (obj.IsField())
+ // - a func parameter or result
+ // - a local var.
+ // Sadly there is no way to distinguish
+ // a param/result from a local
+ // so we must proceed to the find.
+
+ case *types.Func:
+ // A func, if not package-level, must be a method.
+ if recv := obj.Type().(*types.Signature).Recv(); recv == nil {
+ return "", fmt.Errorf("func is not a method: %v", obj)
+ }
+ // TODO(adonovan): opt: if the method is concrete,
+ // do a specialized version of the rest of this function so
+ // that it's O(1) not O(|scope|). Basically 'find' is needed
+ // only for struct fields and interface methods.
+
+ default:
+ panic(obj)
+ }
+
+ // 4. Search the API for the path to the var (field/param/result) or method.
+
+ // First inspect package-level named types.
+ // In the presence of path aliases, these give
+ // the best paths because non-types may
+ // refer to types, but not the reverse.
+ empty := make([]byte, 0, 48) // initial space
+ for _, name := range scope.Names() {
+ o := scope.Lookup(name)
+ tname, ok := o.(*types.TypeName)
+ if !ok {
+ continue // handle non-types in second pass
+ }
+
+ path := append(empty, name...)
+ path = append(path, opType)
+
+ T := o.Type()
+
+ if tname.IsAlias() {
+ // type alias
+ if r := find(obj, T, path); r != nil {
+ return Path(r), nil
+ }
+ } else {
+ // defined (named) type
+ if r := find(obj, T.Underlying(), append(path, opUnderlying)); r != nil {
+ return Path(r), nil
+ }
+ }
+ }
+
+ // Then inspect everything else:
+ // non-types, and declared methods of defined types.
+ for _, name := range scope.Names() {
+ o := scope.Lookup(name)
+ path := append(empty, name...)
+ if _, ok := o.(*types.TypeName); !ok {
+ if o.Exported() {
+ // exported non-type (const, var, func)
+ if r := find(obj, o.Type(), append(path, opType)); r != nil {
+ return Path(r), nil
+ }
+ }
+ continue
+ }
+
+ // Inspect declared methods of defined types.
+ if T, ok := o.Type().(*types.Named); ok {
+ path = append(path, opType)
+ for i := 0; i < T.NumMethods(); i++ {
+ m := T.Method(i)
+ path2 := appendOpArg(path, opMethod, i)
+ if m == obj {
+ return Path(path2), nil // found declared method
+ }
+ if r := find(obj, m.Type(), append(path2, opType)); r != nil {
+ return Path(r), nil
+ }
+ }
+ }
+ }
+
+ return "", fmt.Errorf("can't find path for %v in %s", obj, pkg.Path())
+}
+
+func appendOpArg(path []byte, op byte, arg int) []byte {
+ path = append(path, op)
+ path = strconv.AppendInt(path, int64(arg), 10)
+ return path
+}
+
+// find finds obj within type T, returning the path to it, or nil if not found.
+func find(obj types.Object, T types.Type, path []byte) []byte {
+ switch T := T.(type) {
+ case *types.Basic, *types.Named:
+ // Named types belonging to pkg were handled already,
+ // so T must belong to another package. No path.
+ return nil
+ case *types.Pointer:
+ return find(obj, T.Elem(), append(path, opElem))
+ case *types.Slice:
+ return find(obj, T.Elem(), append(path, opElem))
+ case *types.Array:
+ return find(obj, T.Elem(), append(path, opElem))
+ case *types.Chan:
+ return find(obj, T.Elem(), append(path, opElem))
+ case *types.Map:
+ if r := find(obj, T.Key(), append(path, opKey)); r != nil {
+ return r
+ }
+ return find(obj, T.Elem(), append(path, opElem))
+ case *types.Signature:
+ if r := find(obj, T.Params(), append(path, opParams)); r != nil {
+ return r
+ }
+ return find(obj, T.Results(), append(path, opResults))
+ case *types.Struct:
+ for i := 0; i < T.NumFields(); i++ {
+ f := T.Field(i)
+ path2 := appendOpArg(path, opField, i)
+ if f == obj {
+ return path2 // found field var
+ }
+ if r := find(obj, f.Type(), append(path2, opType)); r != nil {
+ return r
+ }
+ }
+ return nil
+ case *types.Tuple:
+ for i := 0; i < T.Len(); i++ {
+ v := T.At(i)
+ path2 := appendOpArg(path, opAt, i)
+ if v == obj {
+ return path2 // found param/result var
+ }
+ if r := find(obj, v.Type(), append(path2, opType)); r != nil {
+ return r
+ }
+ }
+ return nil
+ case *types.Interface:
+ for i := 0; i < T.NumMethods(); i++ {
+ m := T.Method(i)
+ path2 := appendOpArg(path, opMethod, i)
+ if m == obj {
+ return path2 // found interface method
+ }
+ if r := find(obj, m.Type(), append(path2, opType)); r != nil {
+ return r
+ }
+ }
+ return nil
+ }
+ panic(T)
+}
+
+// Object returns the object denoted by path p within the package pkg.
+func Object(pkg *types.Package, p Path) (types.Object, error) {
+ if p == "" {
+ return nil, fmt.Errorf("empty path")
+ }
+
+ pathstr := string(p)
+ var pkgobj, suffix string
+ if dot := strings.IndexByte(pathstr, opType); dot < 0 {
+ pkgobj = pathstr
+ } else {
+ pkgobj = pathstr[:dot]
+ suffix = pathstr[dot:] // suffix starts with "."
+ }
+
+ obj := pkg.Scope().Lookup(pkgobj)
+ if obj == nil {
+ return nil, fmt.Errorf("package %s does not contain %q", pkg.Path(), pkgobj)
+ }
+
+ // abtraction of *types.{Pointer,Slice,Array,Chan,Map}
+ type hasElem interface {
+ Elem() types.Type
+ }
+ // abstraction of *types.{Interface,Named}
+ type hasMethods interface {
+ Method(int) *types.Func
+ NumMethods() int
+ }
+
+ // The loop state is the pair (t, obj),
+ // exactly one of which is non-nil, initially obj.
+ // All suffixes start with '.' (the only object->type operation),
+ // followed by optional type->type operations,
+ // then a type->object operation.
+ // The cycle then repeats.
+ var t types.Type
+ for suffix != "" {
+ code := suffix[0]
+ suffix = suffix[1:]
+
+ // Codes [AFM] have an integer operand.
+ var index int
+ switch code {
+ case opAt, opField, opMethod:
+ rest := strings.TrimLeft(suffix, "0123456789")
+ numerals := suffix[:len(suffix)-len(rest)]
+ suffix = rest
+ i, err := strconv.Atoi(numerals)
+ if err != nil {
+ return nil, fmt.Errorf("invalid path: bad numeric operand %q for code %q", numerals, code)
+ }
+ index = int(i)
+ case opObj:
+ // no operand
+ default:
+ // The suffix must end with a type->object operation.
+ if suffix == "" {
+ return nil, fmt.Errorf("invalid path: ends with %q, want [AFMO]", code)
+ }
+ }
+
+ if code == opType {
+ if t != nil {
+ return nil, fmt.Errorf("invalid path: unexpected %q in type context", opType)
+ }
+ t = obj.Type()
+ obj = nil
+ continue
+ }
+
+ if t == nil {
+ return nil, fmt.Errorf("invalid path: code %q in object context", code)
+ }
+
+ // Inv: t != nil, obj == nil
+
+ switch code {
+ case opElem:
+ hasElem, ok := t.(hasElem) // Pointer, Slice, Array, Chan, Map
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %T, want pointer, slice, array, chan or map)", code, t, t)
+ }
+ t = hasElem.Elem()
+
+ case opKey:
+ mapType, ok := t.(*types.Map)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %T, want map)", code, t, t)
+ }
+ t = mapType.Key()
+
+ case opParams:
+ sig, ok := t.(*types.Signature)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t)
+ }
+ t = sig.Params()
+
+ case opResults:
+ sig, ok := t.(*types.Signature)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t)
+ }
+ t = sig.Results()
+
+ case opUnderlying:
+ named, ok := t.(*types.Named)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %s, want named)", code, t, t)
+ }
+ t = named.Underlying()
+
+ case opAt:
+ tuple, ok := t.(*types.Tuple)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %s, want tuple)", code, t, t)
+ }
+ if n := tuple.Len(); index >= n {
+ return nil, fmt.Errorf("tuple index %d out of range [0-%d)", index, n)
+ }
+ obj = tuple.At(index)
+ t = nil
+
+ case opField:
+ structType, ok := t.(*types.Struct)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %T, want struct)", code, t, t)
+ }
+ if n := structType.NumFields(); index >= n {
+ return nil, fmt.Errorf("field index %d out of range [0-%d)", index, n)
+ }
+ obj = structType.Field(index)
+ t = nil
+
+ case opMethod:
+ hasMethods, ok := t.(hasMethods) // Interface or Named
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %s, want interface or named)", code, t, t)
+ }
+ if n := hasMethods.NumMethods(); index >= n {
+ return nil, fmt.Errorf("method index %d out of range [0-%d)", index, n)
+ }
+ obj = hasMethods.Method(index)
+ t = nil
+
+ case opObj:
+ named, ok := t.(*types.Named)
+ if !ok {
+ return nil, fmt.Errorf("cannot apply %q to %s (got %s, want named)", code, t, t)
+ }
+ obj = named.Obj()
+ t = nil
+
+ default:
+ return nil, fmt.Errorf("invalid path: unknown code %q", code)
+ }
+ }
+
+ if obj.Pkg() != pkg {
+ return nil, fmt.Errorf("path denotes %s, which belongs to a different package", obj)
+ }
+
+ return obj, nil // success
+}
--- /dev/null
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeutil
+
+import (
+ "go/ast"
+ "go/types"
+
+ "golang.org/x/tools/go/ast/astutil"
+)
+
+// Callee returns the named target of a function call, if any:
+// a function, method, builtin, or variable.
+func Callee(info *types.Info, call *ast.CallExpr) types.Object {
+ var obj types.Object
+ switch fun := astutil.Unparen(call.Fun).(type) {
+ case *ast.Ident:
+ obj = info.Uses[fun] // type, var, builtin, or declared func
+ case *ast.SelectorExpr:
+ if sel, ok := info.Selections[fun]; ok {
+ obj = sel.Obj() // method or field
+ } else {
+ obj = info.Uses[fun.Sel] // qualified identifier?
+ }
+ }
+ if _, ok := obj.(*types.TypeName); ok {
+ return nil // T(x) is a conversion, not a call
+ }
+ return obj
+}
+
+// StaticCallee returns the target (function or method) of a static
+// function call, if any. It returns nil for calls to builtins.
+func StaticCallee(info *types.Info, call *ast.CallExpr) *types.Func {
+ if f, ok := Callee(info, call).(*types.Func); ok && !interfaceMethod(f) {
+ return f
+ }
+ return nil
+}
+
+func interfaceMethod(f *types.Func) bool {
+ recv := f.Type().(*types.Signature).Recv()
+ return recv != nil && types.IsInterface(recv.Type())
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeutil
+
+import "go/types"
+
+// Dependencies returns all dependencies of the specified packages.
+//
+// Dependent packages appear in topological order: if package P imports
+// package Q, Q appears earlier than P in the result.
+// The algorithm follows import statements in the order they
+// appear in the source code, so the result is a total order.
+//
+func Dependencies(pkgs ...*types.Package) []*types.Package {
+ var result []*types.Package
+ seen := make(map[*types.Package]bool)
+ var visit func(pkgs []*types.Package)
+ visit = func(pkgs []*types.Package) {
+ for _, p := range pkgs {
+ if !seen[p] {
+ seen[p] = true
+ visit(p.Imports())
+ result = append(result, p)
+ }
+ }
+ }
+ visit(pkgs)
+ return result
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package typeutil defines various utilities for types, such as Map,
+// a mapping from types.Type to interface{} values.
+package typeutil // import "golang.org/x/tools/go/types/typeutil"
+
+import (
+ "bytes"
+ "fmt"
+ "go/types"
+ "reflect"
+)
+
+// Map is a hash-table-based mapping from types (types.Type) to
+// arbitrary interface{} values. The concrete types that implement
+// the Type interface are pointers. Since they are not canonicalized,
+// == cannot be used to check for equivalence, and thus we cannot
+// simply use a Go map.
+//
+// Just as with map[K]V, a nil *Map is a valid empty map.
+//
+// Not thread-safe.
+//
+type Map struct {
+ hasher Hasher // shared by many Maps
+ table map[uint32][]entry // maps hash to bucket; entry.key==nil means unused
+ length int // number of map entries
+}
+
+// entry is an entry (key/value association) in a hash bucket.
+type entry struct {
+ key types.Type
+ value interface{}
+}
+
+// SetHasher sets the hasher used by Map.
+//
+// All Hashers are functionally equivalent but contain internal state
+// used to cache the results of hashing previously seen types.
+//
+// A single Hasher created by MakeHasher() may be shared among many
+// Maps. This is recommended if the instances have many keys in
+// common, as it will amortize the cost of hash computation.
+//
+// A Hasher may grow without bound as new types are seen. Even when a
+// type is deleted from the map, the Hasher never shrinks, since other
+// types in the map may reference the deleted type indirectly.
+//
+// Hashers are not thread-safe, and read-only operations such as
+// Map.Lookup require updates to the hasher, so a full Mutex lock (not a
+// read-lock) is require around all Map operations if a shared
+// hasher is accessed from multiple threads.
+//
+// If SetHasher is not called, the Map will create a private hasher at
+// the first call to Insert.
+//
+func (m *Map) SetHasher(hasher Hasher) {
+ m.hasher = hasher
+}
+
+// Delete removes the entry with the given key, if any.
+// It returns true if the entry was found.
+//
+func (m *Map) Delete(key types.Type) bool {
+ if m != nil && m.table != nil {
+ hash := m.hasher.Hash(key)
+ bucket := m.table[hash]
+ for i, e := range bucket {
+ if e.key != nil && types.Identical(key, e.key) {
+ // We can't compact the bucket as it
+ // would disturb iterators.
+ bucket[i] = entry{}
+ m.length--
+ return true
+ }
+ }
+ }
+ return false
+}
+
+// At returns the map entry for the given key.
+// The result is nil if the entry is not present.
+//
+func (m *Map) At(key types.Type) interface{} {
+ if m != nil && m.table != nil {
+ for _, e := range m.table[m.hasher.Hash(key)] {
+ if e.key != nil && types.Identical(key, e.key) {
+ return e.value
+ }
+ }
+ }
+ return nil
+}
+
+// Set sets the map entry for key to val,
+// and returns the previous entry, if any.
+func (m *Map) Set(key types.Type, value interface{}) (prev interface{}) {
+ if m.table != nil {
+ hash := m.hasher.Hash(key)
+ bucket := m.table[hash]
+ var hole *entry
+ for i, e := range bucket {
+ if e.key == nil {
+ hole = &bucket[i]
+ } else if types.Identical(key, e.key) {
+ prev = e.value
+ bucket[i].value = value
+ return
+ }
+ }
+
+ if hole != nil {
+ *hole = entry{key, value} // overwrite deleted entry
+ } else {
+ m.table[hash] = append(bucket, entry{key, value})
+ }
+ } else {
+ if m.hasher.memo == nil {
+ m.hasher = MakeHasher()
+ }
+ hash := m.hasher.Hash(key)
+ m.table = map[uint32][]entry{hash: {entry{key, value}}}
+ }
+
+ m.length++
+ return
+}
+
+// Len returns the number of map entries.
+func (m *Map) Len() int {
+ if m != nil {
+ return m.length
+ }
+ return 0
+}
+
+// Iterate calls function f on each entry in the map in unspecified order.
+//
+// If f should mutate the map, Iterate provides the same guarantees as
+// Go maps: if f deletes a map entry that Iterate has not yet reached,
+// f will not be invoked for it, but if f inserts a map entry that
+// Iterate has not yet reached, whether or not f will be invoked for
+// it is unspecified.
+//
+func (m *Map) Iterate(f func(key types.Type, value interface{})) {
+ if m != nil {
+ for _, bucket := range m.table {
+ for _, e := range bucket {
+ if e.key != nil {
+ f(e.key, e.value)
+ }
+ }
+ }
+ }
+}
+
+// Keys returns a new slice containing the set of map keys.
+// The order is unspecified.
+func (m *Map) Keys() []types.Type {
+ keys := make([]types.Type, 0, m.Len())
+ m.Iterate(func(key types.Type, _ interface{}) {
+ keys = append(keys, key)
+ })
+ return keys
+}
+
+func (m *Map) toString(values bool) string {
+ if m == nil {
+ return "{}"
+ }
+ var buf bytes.Buffer
+ fmt.Fprint(&buf, "{")
+ sep := ""
+ m.Iterate(func(key types.Type, value interface{}) {
+ fmt.Fprint(&buf, sep)
+ sep = ", "
+ fmt.Fprint(&buf, key)
+ if values {
+ fmt.Fprintf(&buf, ": %q", value)
+ }
+ })
+ fmt.Fprint(&buf, "}")
+ return buf.String()
+}
+
+// String returns a string representation of the map's entries.
+// Values are printed using fmt.Sprintf("%v", v).
+// Order is unspecified.
+//
+func (m *Map) String() string {
+ return m.toString(true)
+}
+
+// KeysString returns a string representation of the map's key set.
+// Order is unspecified.
+//
+func (m *Map) KeysString() string {
+ return m.toString(false)
+}
+
+////////////////////////////////////////////////////////////////////////
+// Hasher
+
+// A Hasher maps each type to its hash value.
+// For efficiency, a hasher uses memoization; thus its memory
+// footprint grows monotonically over time.
+// Hashers are not thread-safe.
+// Hashers have reference semantics.
+// Call MakeHasher to create a Hasher.
+type Hasher struct {
+ memo map[types.Type]uint32
+}
+
+// MakeHasher returns a new Hasher instance.
+func MakeHasher() Hasher {
+ return Hasher{make(map[types.Type]uint32)}
+}
+
+// Hash computes a hash value for the given type t such that
+// Identical(t, t') => Hash(t) == Hash(t').
+func (h Hasher) Hash(t types.Type) uint32 {
+ hash, ok := h.memo[t]
+ if !ok {
+ hash = h.hashFor(t)
+ h.memo[t] = hash
+ }
+ return hash
+}
+
+// hashString computes the Fowler–Noll–Vo hash of s.
+func hashString(s string) uint32 {
+ var h uint32
+ for i := 0; i < len(s); i++ {
+ h ^= uint32(s[i])
+ h *= 16777619
+ }
+ return h
+}
+
+// hashFor computes the hash of t.
+func (h Hasher) hashFor(t types.Type) uint32 {
+ // See Identical for rationale.
+ switch t := t.(type) {
+ case *types.Basic:
+ return uint32(t.Kind())
+
+ case *types.Array:
+ return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())
+
+ case *types.Slice:
+ return 9049 + 2*h.Hash(t.Elem())
+
+ case *types.Struct:
+ var hash uint32 = 9059
+ for i, n := 0, t.NumFields(); i < n; i++ {
+ f := t.Field(i)
+ if f.Anonymous() {
+ hash += 8861
+ }
+ hash += hashString(t.Tag(i))
+ hash += hashString(f.Name()) // (ignore f.Pkg)
+ hash += h.Hash(f.Type())
+ }
+ return hash
+
+ case *types.Pointer:
+ return 9067 + 2*h.Hash(t.Elem())
+
+ case *types.Signature:
+ var hash uint32 = 9091
+ if t.Variadic() {
+ hash *= 8863
+ }
+ return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())
+
+ case *types.Interface:
+ var hash uint32 = 9103
+ for i, n := 0, t.NumMethods(); i < n; i++ {
+ // See go/types.identicalMethods for rationale.
+ // Method order is not significant.
+ // Ignore m.Pkg().
+ m := t.Method(i)
+ hash += 3*hashString(m.Name()) + 5*h.Hash(m.Type())
+ }
+ return hash
+
+ case *types.Map:
+ return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())
+
+ case *types.Chan:
+ return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())
+
+ case *types.Named:
+ // Not safe with a copying GC; objects may move.
+ return uint32(reflect.ValueOf(t.Obj()).Pointer())
+
+ case *types.Tuple:
+ return h.hashTuple(t)
+ }
+ panic(t)
+}
+
+func (h Hasher) hashTuple(tuple *types.Tuple) uint32 {
+ // See go/types.identicalTypes for rationale.
+ n := tuple.Len()
+ var hash uint32 = 9137 + 2*uint32(n)
+ for i := 0; i < n; i++ {
+ hash += 3 * h.Hash(tuple.At(i).Type())
+ }
+ return hash
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file implements a cache of method sets.
+
+package typeutil
+
+import (
+ "go/types"
+ "sync"
+)
+
+// A MethodSetCache records the method set of each type T for which
+// MethodSet(T) is called so that repeat queries are fast.
+// The zero value is a ready-to-use cache instance.
+type MethodSetCache struct {
+ mu sync.Mutex
+ named map[*types.Named]struct{ value, pointer *types.MethodSet } // method sets for named N and *N
+ others map[types.Type]*types.MethodSet // all other types
+}
+
+// MethodSet returns the method set of type T. It is thread-safe.
+//
+// If cache is nil, this function is equivalent to types.NewMethodSet(T).
+// Utility functions can thus expose an optional *MethodSetCache
+// parameter to clients that care about performance.
+//
+func (cache *MethodSetCache) MethodSet(T types.Type) *types.MethodSet {
+ if cache == nil {
+ return types.NewMethodSet(T)
+ }
+ cache.mu.Lock()
+ defer cache.mu.Unlock()
+
+ switch T := T.(type) {
+ case *types.Named:
+ return cache.lookupNamed(T).value
+
+ case *types.Pointer:
+ if N, ok := T.Elem().(*types.Named); ok {
+ return cache.lookupNamed(N).pointer
+ }
+ }
+
+ // all other types
+ // (The map uses pointer equivalence, not type identity.)
+ mset := cache.others[T]
+ if mset == nil {
+ mset = types.NewMethodSet(T)
+ if cache.others == nil {
+ cache.others = make(map[types.Type]*types.MethodSet)
+ }
+ cache.others[T] = mset
+ }
+ return mset
+}
+
+func (cache *MethodSetCache) lookupNamed(named *types.Named) struct{ value, pointer *types.MethodSet } {
+ if cache.named == nil {
+ cache.named = make(map[*types.Named]struct{ value, pointer *types.MethodSet })
+ }
+ // Avoid recomputing mset(*T) for each distinct Pointer
+ // instance whose underlying type is a named type.
+ msets, ok := cache.named[named]
+ if !ok {
+ msets.value = types.NewMethodSet(named)
+ msets.pointer = types.NewMethodSet(types.NewPointer(named))
+ cache.named[named] = msets
+ }
+ return msets
+}
--- /dev/null
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeutil
+
+// This file defines utilities for user interfaces that display types.
+
+import "go/types"
+
+// IntuitiveMethodSet returns the intuitive method set of a type T,
+// which is the set of methods you can call on an addressable value of
+// that type.
+//
+// The result always contains MethodSet(T), and is exactly MethodSet(T)
+// for interface types and for pointer-to-concrete types.
+// For all other concrete types T, the result additionally
+// contains each method belonging to *T if there is no identically
+// named method on T itself.
+//
+// This corresponds to user intuition about method sets;
+// this function is intended only for user interfaces.
+//
+// The order of the result is as for types.MethodSet(T).
+//
+func IntuitiveMethodSet(T types.Type, msets *MethodSetCache) []*types.Selection {
+ isPointerToConcrete := func(T types.Type) bool {
+ ptr, ok := T.(*types.Pointer)
+ return ok && !types.IsInterface(ptr.Elem())
+ }
+
+ var result []*types.Selection
+ mset := msets.MethodSet(T)
+ if types.IsInterface(T) || isPointerToConcrete(T) {
+ for i, n := 0, mset.Len(); i < n; i++ {
+ result = append(result, mset.At(i))
+ }
+ } else {
+ // T is some other concrete type.
+ // Report methods of T and *T, preferring those of T.
+ pmset := msets.MethodSet(types.NewPointer(T))
+ for i, n := 0, pmset.Len(); i < n; i++ {
+ meth := pmset.At(i)
+ if m := mset.Lookup(meth.Obj().Pkg(), meth.Obj().Name()); m != nil {
+ meth = m
+ }
+ result = append(result, meth)
+ }
+
+ }
+ return result
+}
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"revision": "90868a75fefd03942536221d7c0e2f84ec62a668",
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+ },
+ {
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