cmd/compile: verify imported types after they are fully imported

Fixes #15548.

Change-Id: I1dfa9c8739a4b6d5e4c737c1a1e09e80e045b7aa
Reviewed-on: https://go-review.googlesource.com/22803
Reviewed-by: Alan Donovan <adonovan@google.com>

diff --git a/src/cmd/compile/internal/gc/bimport.go b/src/cmd/compile/internal/gc/bimport.go
index 167a36b2c02dc1a08298e826a3bd53ef44311555..6b0593cd472fc450ba4fb5aa842a5c40f1a06e35 100644 (file)
--- a/src/cmd/compile/internal/gc/bimport.go
+++ b/src/cmd/compile/internal/gc/bimport.go
@@ -29,6 +29,9 @@ type importer struct {
        typList  []*Type
        funcList []*Node // nil entry means already declared
 
+       // for delayed type verification
+       cmpList []struct{ pt, t *Type }
+
        // position encoding
        posInfoFormat bool
        prevFile      string
@@ -175,6 +178,8 @@ func Import(in *bufio.Reader) {
                Fatalf("importer: unexpected context %d", dclcontext)
        }
 
+       p.verifyTypes()
+
        // --- end of export data ---
 
        typecheckok = tcok
@@ -183,6 +188,19 @@ func Import(in *bufio.Reader) {
        testdclstack() // debugging only
 }
 
+func (p *importer) verifyTypes() {
+       for _, pair := range p.cmpList {
+               pt := pair.pt
+               t := pair.t
+               if !Eqtype(pt.Orig, t) {
+                       // TODO(gri) Is this a possible regular error (stale files)
+                       // or can this only happen if export/import is flawed?
+                       // (if the latter, change to Fatalf here)
+                       Yyerror("inconsistent definition for type %v during import\n\t%v (in %q)\n\t%v (in %q)", pt.Sym, Tconv(pt, FmtLong), pt.Sym.Importdef.Path, Tconv(t, FmtLong), importpkg.Path)
+               }
+       }
+}
+
 func (p *importer) pkg() *Pkg {
        // if the package was seen before, i is its index (>= 0)
        i := p.tagOrIndex()
@@ -317,6 +335,38 @@ func (p *importer) newtyp(etype EType) *Type {
        return t
 }
 
+// This is like the function importtype but it delays the
+// type identity check for types that have been seen already.
+// importer.importtype and importtype and (export.go) need to
+// remain in sync.
+func (p *importer) importtype(pt, t *Type) {
+       // override declaration in unsafe.go for Pointer.
+       // there is no way in Go code to define unsafe.Pointer
+       // so we have to supply it.
+       if incannedimport != 0 && importpkg.Name == "unsafe" && pt.Nod.Sym.Name == "Pointer" {
+               t = Types[TUNSAFEPTR]
+       }
+
+       if pt.Etype == TFORW {
+               n := pt.Nod
+               copytype(pt.Nod, t)
+               pt.Nod = n // unzero nod
+               pt.Sym.Importdef = importpkg
+               pt.Sym.Lastlineno = lineno
+               declare(n, PEXTERN)
+               checkwidth(pt)
+       } else {
+               // pt.Orig and t must be identical. Since t may not be
+               // fully set up yet, collect the types and verify identity
+               // later.
+               p.cmpList = append(p.cmpList, struct{ pt, t *Type }{pt, t})
+       }
+
+       if Debug['E'] != 0 {
+               fmt.Printf("import type %v %v\n", pt, Tconv(t, FmtLong))
+       }
+}
+
 func (p *importer) typ() *Type {
        // if the type was seen before, i is its index (>= 0)
        i := p.tagOrIndex()
@@ -339,7 +389,7 @@ func (p *importer) typ() *Type {
                // read underlying type
                // parser.go:hidden_type
                t0 := p.typ()
-               importtype(t, t0) // parser.go:hidden_import
+               p.importtype(t, t0) // parser.go:hidden_import
 
                // interfaces don't have associated methods
                if t0.IsInterface() {

diff --git a/src/cmd/compile/internal/gc/export.go b/src/cmd/compile/internal/gc/export.go
index 0a0fbc6b85ee70e0f64c8a4775c63e1f54e321dc..2dd137ed773c44cb39effd8102b3baa187bbe40f 100644 (file)
--- a/src/cmd/compile/internal/gc/export.go
+++ b/src/cmd/compile/internal/gc/export.go
@@ -551,6 +551,7 @@ func importvar(s *Sym, t *Type) {
        }
 }
 
+// importtype and importer.importtype (bimport.go) need to remain in sync.
 func importtype(pt *Type, t *Type) {
        // override declaration in unsafe.go for Pointer.
        // there is no way in Go code to define unsafe.Pointer

diff --git a/test/fixedbugs/issue15548.dir/a.go b/test/fixedbugs/issue15548.dir/a.go
new file mode 100644 (file)
index 0000000..3c593fc
--- /dev/null
+++ b/test/fixedbugs/issue15548.dir/a.go
@@ -0,0 +1,17 @@
+// 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 a
+
+type I0 interface {
+       I1
+}
+
+type T struct {
+       I1
+}
+
+type I1 interface {
+       M(*T) // removing * makes crash go away
+}

diff --git a/test/fixedbugs/issue15548.dir/b.go b/test/fixedbugs/issue15548.dir/b.go
new file mode 100644 (file)
index 0000000..b46f5ad
--- /dev/null
+++ b/test/fixedbugs/issue15548.dir/b.go
@@ -0,0 +1,9 @@
+// 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 b
+
+import "./a"
+
+var X a.T

diff --git a/test/fixedbugs/issue15548.dir/c.go b/test/fixedbugs/issue15548.dir/c.go
new file mode 100644 (file)
index 0000000..ce6e320
--- /dev/null
+++ b/test/fixedbugs/issue15548.dir/c.go
@@ -0,0 +1,10 @@
+// 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 c
+
+import (
+       _ "./a"
+       _ "./b"
+)

diff --git a/test/fixedbugs/issue15548.go b/test/fixedbugs/issue15548.go
new file mode 100644 (file)
index 0000000..4d2844d
--- /dev/null
+++ b/test/fixedbugs/issue15548.go
@@ -0,0 +1,7 @@
+// compiledir
+
+// 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 ignored