cmd/compile/internal/syntax: implement Pos.FileBase method (cleanup)

Factor out file base computation into a method.

Change-Id: Ia6de100459b6df2919f2320872890320aa88866d
Reviewed-on: https://go-review.googlesource.com/c/go/+/586156
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

diff --git a/src/cmd/compile/internal/noder/irgen.go b/src/cmd/compile/internal/noder/irgen.go
index d54ec05b6a47afd7dc0e00d082e8d83418330238..4d51c6b44678fc3ff5b753c9ec932bf6fdfc8f10 100644 (file)
--- a/src/cmd/compile/internal/noder/irgen.go
+++ b/src/cmd/compile/internal/noder/irgen.go
@@ -29,9 +29,9 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
 
        // setup and syntax error reporting
        files := make([]*syntax.File, len(noders))
-       // posBaseMap maps all file pos bases back to *syntax.File
+       // fileBaseMap maps all file pos bases back to *syntax.File
        // for checking Go version mismatched.
-       posBaseMap := make(map[*syntax.PosBase]*syntax.File)
+       fileBaseMap := make(map[*syntax.PosBase]*syntax.File)
        for i, p := range noders {
                files[i] = p.file
                // The file.Pos() is the position of the package clause.
@@ -40,7 +40,7 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
                // Make sure to consistently map back to file base, here and
                // when we look for a file in the conf.Error handler below,
                // otherwise the file may not be found (was go.dev/issue/67141).
-               posBaseMap[fileBase(p.file.Pos())] = p.file
+               fileBaseMap[p.file.Pos().FileBase()] = p.file
        }
 
        // typechecking
@@ -75,9 +75,9 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
                terr := err.(types2.Error)
                msg := terr.Msg
                if versionErrorRx.MatchString(msg) {
-                       posBase := fileBase(terr.Pos)
-                       fileVersion := info.FileVersions[posBase]
-                       file := posBaseMap[posBase]
+                       fileBase := terr.Pos.FileBase()
+                       fileVersion := info.FileVersions[fileBase]
+                       file := fileBaseMap[fileBase]
                        if file == nil {
                                // This should never happen, but be careful and don't crash.
                        } else if file.GoVersion == fileVersion {
@@ -155,15 +155,6 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
        return pkg, info
 }
 
-// fileBase returns a file's position base given a position in the file.
-func fileBase(pos syntax.Pos) *syntax.PosBase {
-       base := pos.Base()
-       for !base.IsFileBase() { // line directive base
-               base = base.Pos().Base()
-       }
-       return base
-}
-
 // A cycleFinder detects anonymous interface cycles (go.dev/issue/56103).
 type cycleFinder struct {
        cyclic map[*types2.Interface]bool

diff --git a/src/cmd/compile/internal/syntax/pos.go b/src/cmd/compile/internal/syntax/pos.go
index dd25d4f249dee6b7b0ed8b9dc937a6e4724b00f8..5ea9f5304ab6124d8c4d4e2d678a296c50f3a704 100644 (file)
--- a/src/cmd/compile/internal/syntax/pos.go
+++ b/src/cmd/compile/internal/syntax/pos.go
@@ -34,6 +34,18 @@ func (pos Pos) Base() *PosBase { return pos.base }
 func (pos Pos) Line() uint     { return uint(pos.line) }
 func (pos Pos) Col() uint      { return uint(pos.col) }
 
+// FileBase returns the PosBase of the file containing pos,
+// skipping over intermediate PosBases from //line directives.
+// The result is nil if pos doesn't have a file base.
+func (pos Pos) FileBase() *PosBase {
+       b := pos.base
+       for b != nil && b != b.pos.base {
+               b = b.pos.base
+       }
+       // b == nil || b == b.pos.base
+       return b
+}
+
 func (pos Pos) RelFilename() string { return pos.base.Filename() }
 
 func (pos Pos) RelLine() uint {

diff --git a/src/cmd/compile/internal/types2/check.go b/src/cmd/compile/internal/types2/check.go
index a347467b597b7b80d2f105342da4203aac219435..3bb28b46b4e78a7773ed8b326fa920524120f9c5 100644 (file)
--- a/src/cmd/compile/internal/types2/check.go
+++ b/src/cmd/compile/internal/types2/check.go
@@ -373,7 +373,7 @@ func (check *Checker) initFiles(files []*syntax.File) {
                                check.errorf(file.PkgName, TooNew, "file requires newer Go version %v", fileVersion)
                        }
                }
-               versions[base(file.Pos())] = v // base(file.Pos()) may be nil for tests
+               versions[file.Pos().FileBase()] = v // file.Pos().FileBase() may be nil for tests
        }
 }
 

diff --git a/src/cmd/compile/internal/types2/version.go b/src/cmd/compile/internal/types2/version.go
index 241b10d3e637289d59953ec1a4fdac641d419d8d..39ecb9c3af2a0a8bce1a84ea67d6d0d916639d40 100644 (file)
--- a/src/cmd/compile/internal/types2/version.go
+++ b/src/cmd/compile/internal/types2/version.go
@@ -5,7 +5,6 @@
 package types2
 
 import (
-       "cmd/compile/internal/syntax"
        "fmt"
        "go/version"
        "internal/goversion"
@@ -56,7 +55,7 @@ var (
 func (check *Checker) allowVersion(at poser, v goVersion) bool {
        fileVersion := check.conf.GoVersion
        if pos := at.Pos(); pos.IsKnown() {
-               fileVersion = check.versions[base(pos)]
+               fileVersion = check.versions[pos.FileBase()]
        }
 
        // We need asGoVersion (which calls version.Lang) below
@@ -76,19 +75,3 @@ func (check *Checker) verifyVersionf(at poser, v goVersion, format string, args
        }
        return true
 }
-
-// base finds the underlying PosBase of the source file containing pos,
-// skipping over intermediate PosBase layers created by //line directives.
-// The positions must be known.
-func base(pos syntax.Pos) *syntax.PosBase {
-       assert(pos.IsKnown())
-       b := pos.Base()
-       for {
-               bb := b.Pos().Base()
-               if bb == nil || bb == b {
-                       break
-               }
-               b = bb
-       }
-       return b
-}