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cmd/cgo: avoid worklist nondeterminism.

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+ Regression test.

Fixes #9026.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/162490043
This commit is contained in:
Alan Donovan 2014-10-30 14:01:14 -04:00
parent f21a02a179
commit 09f6f05c1f
3 changed files with 49 additions and 9 deletions
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1
misc/cgo/test/cgo_test.go
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@ -62,5 +62,6 @@ func Test8517(t *testing.T) { test8517(t) }
func Test8811(t *testing.T) { test8811(t) }
func TestReturnAfterGrow(t *testing.T) { testReturnAfterGrow(t) }
func TestReturnAfterGrowFromGo(t *testing.T) { testReturnAfterGrowFromGo(t) }
func Test9026(t *testing.T) { test9026(t) }
func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }

33
misc/cgo/test/issue9026.go Normal file
View File

@ -0,0 +1,33 @@
package cgotest
/*
typedef struct {} git_merge_file_input;
typedef struct {} git_merge_file_options;
int git_merge_file(
git_merge_file_input *in,
git_merge_file_options *opts) {}
*/
import "C"
import (
"fmt"
"testing"
)
func test9026(t *testing.T) {
var in C.git_merge_file_input
var opts *C.git_merge_file_options
C.git_merge_file(&in, opts)
// Test that the generated type names are deterministic.
// (Previously this would fail about 10% of the time.)
//
// Brittle: the assertion may fail spuriously when the algorithm
// changes, but should remain stable otherwise.
got := fmt.Sprintf("%T %T", in, opts)
want := "cgotest._Ctype_struct___12 *cgotest._Ctype_struct___13"
if got != want {
t.Errorf("Non-deterministic type names: got %s, want %s", got, want)
}
}

24
src/cmd/cgo/gcc.go
View File

@ -944,6 +944,8 @@ type typeConv struct {
// Map from types to incomplete pointers to those types.
ptrs map[dwarf.Type][]*Type
// Keys of ptrs in insertion order (deterministic worklist)
ptrKeys []dwarf.Type
// Predeclared types.
bool ast.Expr
@ -1061,16 +1063,17 @@ func (tr *TypeRepr) Set(repr string, fargs ...interface{}) {
func (c *typeConv) FinishType(pos token.Pos) {
// Completing one pointer type might produce more to complete.
// Keep looping until they're all done.
for len(c.ptrs) > 0 {
for dtype := range c.ptrs {
// Note Type might invalidate c.ptrs[dtype].
t := c.Type(dtype, pos)
for _, ptr := range c.ptrs[dtype] {
ptr.Go.(*ast.StarExpr).X = t.Go
ptr.C.Set("%s*", t.C)
}
delete(c.ptrs, dtype)
for len(c.ptrKeys) > 0 {
dtype := c.ptrKeys[0]
c.ptrKeys = c.ptrKeys[1:]
// Note Type might invalidate c.ptrs[dtype].
t := c.Type(dtype, pos)
for _, ptr := range c.ptrs[dtype] {
ptr.Go.(*ast.StarExpr).X = t.Go
ptr.C.Set("%s*", t.C)
}
c.ptrs[dtype] = nil // retain the map key
}
}
@ -1237,6 +1240,9 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
// Placeholder initialization; completed in FinishType.
t.Go = &ast.StarExpr{}
t.C.Set("<incomplete>*")
if _, ok := c.ptrs[dt.Type]; !ok {
c.ptrKeys = append(c.ptrKeys, dt.Type)
}
c.ptrs[dt.Type] = append(c.ptrs[dt.Type], t)
case *dwarf.QualType: