cgo: add basic gccgo support.

R=rsc, iant
CC=golang-dev, remy
https://golang.org/cl/5485070

diff --git a/src/cmd/cgo/main.go b/src/cmd/cgo/main.go
index 2749ca74f28321d93f43e843f109dece192b2076..96d304ab7611dcc8efa30b44797d588036dbe918 100644 (file)
--- a/src/cmd/cgo/main.go
+++ b/src/cmd/cgo/main.go
@@ -130,6 +130,8 @@ var dynobj = flag.String("dynimport", "", "if non-empty, print dynamic import da
 var godefs = flag.Bool("godefs", false, "for bootstrap: write Go definitions for C file to standard output")
 var cdefs = flag.Bool("cdefs", false, "for bootstrap: write C definitions for C file to standard output")
 
+var gccgo = flag.Bool("gccgo", false, "generate files for use with gccgo")
+
 var goarch, goos string
 
 func main() {

diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index e4709ae54c117dd8f9efbeb42fc1b9026abf41cd..2e0a56987ac830a2ba7d81891070fed58d68137d 100644 (file)
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -46,7 +46,9 @@ func (p *Package) writeDefs() {
        fmt.Fprintf(fgo2, "package %s\n\n", p.PackageName)
        fmt.Fprintf(fgo2, "import \"unsafe\"\n\n")
        fmt.Fprintf(fgo2, "import \"syscall\"\n\n")
-       fmt.Fprintf(fgo2, "import _ \"runtime/cgo\"\n\n")
+       if !*gccgo {
+               fmt.Fprintf(fgo2, "import _ \"runtime/cgo\"\n\n")
+       }
        fmt.Fprintf(fgo2, "type _ unsafe.Pointer\n\n")
        fmt.Fprintf(fgo2, "func _Cerrno(dst *error, x int) { *dst = syscall.Errno(x) }\n")
 
@@ -57,7 +59,11 @@ func (p *Package) writeDefs() {
        }
        fmt.Fprintf(fgo2, "type _Ctype_void [0]byte\n")
 
-       fmt.Fprintf(fc, cProlog)
+       if *gccgo {
+               fmt.Fprintf(fc, cPrologGccgo)
+       } else {
+               fmt.Fprintf(fc, cProlog)
+       }
 
        cVars := make(map[string]bool)
        for _, n := range p.Name {
@@ -238,13 +244,22 @@ func (p *Package) writeDefsFunc(fc, fgo2 *os.File, n *Name) {
                Type: gtype,
        }
        printer.Fprint(fgo2, fset, d)
-       fmt.Fprintf(fgo2, "\n")
+       if *gccgo {
+               fmt.Fprintf(fgo2, " __asm__(\"%s\")\n", n.C)
+       } else {
+               fmt.Fprintf(fgo2, "\n")
+       }
 
        if name == "CString" || name == "GoString" || name == "GoStringN" || name == "GoBytes" {
                // The builtins are already defined in the C prolog.
                return
        }
 
+       // gccgo does not require a wrapper unless an error must be returned.
+       if *gccgo && !n.AddError {
+               return
+       }
+
        var argSize int64
        _, argSize = p.structType(n)
 
@@ -730,6 +745,42 @@ void
 }
 `
 
+const cPrologGccgo = `
+#include <stdint.h>
+#include <string.h>
+
+struct __go_string {
+       const unsigned char *__data;
+       int __length;
+};
+
+typedef struct __go_open_array {
+       void* __values;
+       int __count;
+       int __capacity;
+} Slice;
+
+struct __go_string __go_byte_array_to_string(const void* p, int len);
+struct __go_open_array __go_string_to_byte_array (struct __go_string str);
+
+const char *CString(struct __go_string s) {
+       return strndup(s.__data, s.__length);
+}
+
+struct __go_string GoString(char *p) {
+       return __go_byte_array_to_string(p, strlen(p));
+}
+
+struct __go_string GoStringN(char *p, int n) {
+       return __go_byte_array_to_string(p, n);
+}
+
+Slice GoBytes(char *p, int n) {
+       struct __go_string s = { p, n };
+       return __go_string_to_byte_array(s);
+}
+`
+
 const gccExportHeaderProlog = `
 typedef unsigned int uint;
 typedef signed char schar;