Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

cmd/cgo: use __gcc_struct__ for go exported functions

Browse source 
Fixes #6833

R=minux.ma, iant
CC=golang-dev
https://golang.org/cl/35790045
This commit is contained in:
Alex Brainman 2013-12-10 11:30:12 +11:00
parent 52ee63f544
commit 6795687427
4 changed files with 54 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

26
src/cmd/cgo/out.go
View file

@ -529,15 +529,8 @@ func (p *Package) writeOutputFunc(fgcc *os.File, n *Name) {
}
// We're trying to write a gcc struct that matches 6c/8c/5c's layout.
// Use packed attribute to force no padding in this struct in case
// gcc has different packing requirements. For example,
// on 386 Windows, gcc wants to 8-align int64s, but 8c does not.
// Use __gcc_struct__ to work around http://gcc.gnu.org/PR52991 on x86,
// and http://golang.org/issue/5603.
extraAttr := ""
if !strings.Contains(p.gccBaseCmd()[0], "clang") && (goarch == "amd64" || goarch == "386") {
extraAttr = ", __gcc_struct__"
}
fmt.Fprintf(fgcc, "\t%s __attribute__((__packed__%v)) *a = v;\n", ctype, extraAttr)
// gcc has different packing requirements.
fmt.Fprintf(fgcc, "\t%s %v *a = v;\n", ctype, p.packedAttribute())
fmt.Fprintf(fgcc, "\t")
if t := n.FuncType.Result; t != nil {
fmt.Fprintf(fgcc, "a->r = ")
@ -618,6 +611,19 @@ func (p *Package) writeGccgoOutputFunc(fgcc *os.File, n *Name) {
fmt.Fprintf(fgcc, "\n")
}
// packedAttribute returns host compiler struct attribute that will be
// used to match 6c/8c/5c's struct layout. For example, on 386 Windows,
// gcc wants to 8-align int64s, but 8c does not.
// Use __gcc_struct__ to work around http://gcc.gnu.org/PR52991 on x86,
// and http://golang.org/issue/5603.
func (p *Package) packedAttribute() string {
s := "__attribute__((__packed__"
if !strings.Contains(p.gccBaseCmd()[0], "clang") && (goarch == "amd64" || goarch == "386") {
s += ", __gcc_struct__"
}
return s + "))"
}
// Write out the various stubs we need to support functions exported
// from Go so that they are callable from C.
func (p *Package) writeExports(fgo2, fc, fm *os.File) {
@ -727,7 +733,7 @@ func (p *Package) writeExports(fgo2, fc, fm *os.File) {
fmt.Fprintf(fgcc, "extern void _cgoexp%s_%s(void *, int);\n", cPrefix, exp.ExpName)
fmt.Fprintf(fgcc, "\n%s\n", s)
fmt.Fprintf(fgcc, "{\n")
fmt.Fprintf(fgcc, "\t%s __attribute__((packed)) a;\n", ctype)
fmt.Fprintf(fgcc, "\t%s %v a;\n", ctype, p.packedAttribute())
if gccResult != "void" && (len(fntype.Results.List) > 1 || len(fntype.Results.List[0].Names) > 1) {
fmt.Fprintf(fgcc, "\t%s r;\n", gccResult)
}