cmd/cgo: use type aliases for #define type macros

Cgo's initial design for handling "#define foo int*" involved
rewriting "C.foo" to "*_Ctype_int" everywhere. But now that we have
type aliases, we can declare "type _Ctype_foo = *_Ctype_int" once, and
then rewrite "C.foo" to just "_Ctype_foo".

This is important for go/types's UsesCgo mode, where go/types needs to
be able to figure out a type for each C.foo identifier using only the
information written into _cgo_gotypes.go.

Fixes #38649.

Change-Id: Ia0f8c2d82df81efb1be5bc26195ea9154c0af871
Reviewed-on: https://go-review.googlesource.com/c/go/+/230037
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Matthew Dempsky 2020-04-30 23:05:51 -07:00
parent f00b8b45a2
commit b565d1ec16
5 changed files with 36 additions and 6 deletions

View file

@ -897,6 +897,10 @@ static uint16_t issue31093F(uint16_t v) { return v; }
// issue 32579
typedef struct S32579 { unsigned char data[1]; } S32579;
// issue 38649
// Test that #define'd type aliases work.
#define netbsd_gid unsigned int
*/
import "C"
@ -2192,3 +2196,7 @@ func test32579(t *testing.T) {
t.Errorf("&s[0].data[0] failed: got %d, want %d", s[0].data[0], 1)
}
}
// issue 38649
var issue38649 C.netbsd_gid = 42

View file

@ -0,0 +1,15 @@
// Copyright 2020 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.
//
// +build ignore
package main
/*
struct Issue38649 { int x; };
#define issue38649 struct Issue38649
*/
import "C"
type issue38649 C.issue38649

View file

@ -19,5 +19,8 @@ var v6 = B{}
// Test that S is fully defined
var v7 = S{}
// Test that #define'd type is fully defined
var _ = issue38649{X: 0}
func main() {
}

View file

@ -23,6 +23,7 @@ var filePrefixes = []string{
"fieldtypedef",
"issue37479",
"issue37621",
"issue38649",
}
func TestGoDefs(t *testing.T) {

View file

@ -182,6 +182,9 @@ func (p *Package) Translate(f *File) {
numTypedefs = len(p.typedefs)
// Also ask about any typedefs we've seen so far.
for _, info := range p.typedefList {
if f.Name[info.typedef] != nil {
continue
}
n := &Name{
Go: info.typedef,
C: info.typedef,
@ -710,6 +713,9 @@ func (p *Package) prepareNames(f *File) {
}
}
p.mangleName(n)
if n.Kind == "type" && typedef[n.Mangle] == nil {
typedef[n.Mangle] = n.Type
}
}
}
@ -1348,6 +1354,9 @@ func (p *Package) rewriteRef(f *File) {
if *godefs {
// Substitute definition for mangled type name.
if r.Name.Type != nil {
expr = r.Name.Type.Go
}
if id, ok := expr.(*ast.Ident); ok {
if t := typedef[id.Name]; t != nil {
expr = t.Go
@ -1413,9 +1422,7 @@ func (p *Package) rewriteName(f *File, r *Ref) ast.Expr {
r.Context = ctxType
if r.Name.Type == nil {
error_(r.Pos(), "invalid conversion to C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
break
}
expr = r.Name.Type.Go
break
}
error_(r.Pos(), "call of non-function C.%s", fixGo(r.Name.Go))
@ -1472,9 +1479,7 @@ func (p *Package) rewriteName(f *File, r *Ref) ast.Expr {
// Okay - might be new(T)
if r.Name.Type == nil {
error_(r.Pos(), "expression C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
break
}
expr = r.Name.Type.Go
case "var":
expr = &ast.StarExpr{Star: (*r.Expr).Pos(), X: expr}
case "macro":
@ -1493,8 +1498,6 @@ func (p *Package) rewriteName(f *File, r *Ref) ast.Expr {
// Use of C.enum_x, C.struct_x or C.union_x without C definition.
// GCC won't raise an error when using pointers to such unknown types.
error_(r.Pos(), "type C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
} else {
expr = r.Name.Type.Go
}
default:
if r.Name.Kind == "func" {