Imported Upstream version 2011.05.22upstream-weekly/2011.05.22

2 files changed, 17 insertions, 9 deletions

diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index ae5ca2c7d..ac6561345 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -604,7 +604,7 @@ const gccTmp = "_obj/_cgo_.o"
 // gccCmd returns the gcc command line to use for compiling
 // the input.
 func (p *Package) gccCmd() []string {
-	return []string{
+	c := []string{
 		p.gccName(),
 		p.gccMachine(),
 		"-Wall",                             // many warnings
@@ -614,15 +614,17 @@ func (p *Package) gccCmd() []string {
 		"-fno-eliminate-unused-debug-types", // gets rid of e.g. untyped enum otherwise
 		"-c",                                // do not link
 		"-xc",                               // input language is C
-		"-",                                 // read input from standard input
 	}
+	c = append(c, p.GccOptions...)
+	c = append(c, "-") //read input from standard input
+	return c
 }
 
 // gccDebug runs gcc -gdwarf-2 over the C program stdin and
 // returns the corresponding DWARF data and any messages
 // printed to standard error.
 func (p *Package) gccDebug(stdin []byte) *dwarf.Data {
-	runGcc(stdin, append(p.gccCmd(), p.GccOptions...))
+	runGcc(stdin, p.gccCmd())
 
 	// Try to parse f as ELF and Mach-O and hope one works.
 	var f interface {
@@ -649,8 +651,8 @@ func (p *Package) gccDebug(stdin []byte) *dwarf.Data {
 // #defines that gcc encountered while processing the input
 // and its included files.
 func (p *Package) gccDefines(stdin []byte) string {
-	base := []string{p.gccName(), p.gccMachine(), "-E", "-dM", "-xc", "-"}
-	stdout, _ := runGcc(stdin, append(base, p.GccOptions...))
+	base := []string{p.gccName(), p.gccMachine(), "-E", "-dM", "-xc"}
+	stdout, _ := runGcc(stdin, append(append(base, p.GccOptions...), "-"))
 	return stdout
 }
 
@@ -659,7 +661,7 @@ func (p *Package) gccDefines(stdin []byte) string {
 // gcc to fail.
 func (p *Package) gccErrors(stdin []byte) string {
 	// TODO(rsc): require failure
-	args := append(p.gccCmd(), p.GccOptions...)
+	args := p.gccCmd()
 	if *debugGcc {
 		fmt.Fprintf(os.Stderr, "$ %s <<EOF\n", strings.Join(args, " "))
 		os.Stderr.Write(stdin)
diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index bc031cc58..2ce4e9752 100644
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -331,7 +331,11 @@ func (p *Package) writeOutputFunc(fgcc *os.File, n *Name) {
 		fmt.Fprintf(fgcc, "\tint e;\n") // assuming 32 bit (see comment above structType)
 		fmt.Fprintf(fgcc, "\terrno = 0;\n")
 	}
-	fmt.Fprintf(fgcc, "\t%s *a = v;\n", ctype)
+	// 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.
+	fmt.Fprintf(fgcc, "\t%s __attribute__((__packed__)) *a = v;\n", ctype)
 	fmt.Fprintf(fgcc, "\t")
 	if t := n.FuncType.Result; t != nil {
 		fmt.Fprintf(fgcc, "a->r = ")
@@ -370,7 +374,9 @@ func (p *Package) writeExports(fgo2, fc, fm *os.File) {
 		fn := exp.Func
 
 		// Construct a gcc struct matching the 6c argument and
-		// result frame.
+		// result frame.  The gcc struct will be compiled with
+		// __attribute__((packed)) so all padding must be accounted
+		// for explicitly.
 		ctype := "struct {\n"
 		off := int64(0)
 		npad := 0
@@ -458,7 +464,7 @@ func (p *Package) writeExports(fgo2, fc, fm *os.File) {
 		fmt.Fprintf(fgcc, "extern _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 a;\n", ctype)
+		fmt.Fprintf(fgcc, "\t%s __attribute__((packed)) a;\n", ctype)
 		if gccResult != "void" && (len(fntype.Results.List) > 1 || len(fntype.Results.List[0].Names) > 1) {
 			fmt.Fprintf(fgcc, "\t%s r;\n", gccResult)
 		}