Imported Upstream version 2011.07.29

4 files changed, 43 insertions, 4 deletions

diff --git a/src/cmd/cgo/ast.go b/src/cmd/cgo/ast.go
index 46e33686d..73b7313d6 100644
--- a/src/cmd/cgo/ast.go
+++ b/src/cmd/cgo/ast.go
@@ -189,6 +189,10 @@ func (f *File) saveExport(x interface{}, context string) {
 			error(c.Pos(), "export missing name")
 		}
 
+		if name != n.Name.Name {
+			error(c.Pos(), "export comment has wrong name %q, want %q", name, n.Name.Name)
+		}
+
 		f.ExpFunc = append(f.ExpFunc, &ExpFunc{
 			Func:    n,
 			ExpName: name,
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go
index 064725c1d..63413825a 100644
--- a/src/cmd/cgo/doc.go
+++ b/src/cmd/cgo/doc.go
@@ -52,6 +52,7 @@ C.char, C.schar (signed char), C.uchar (unsigned char),
 C.short, C.ushort (unsigned short), C.int, C.uint (unsigned int),
 C.long, C.ulong (unsigned long), C.longlong (long long),
 C.ulonglong (unsigned long long), C.float, C.double.
+The C type void* is represented by Go's unsafe.Pointer.
 
 To access a struct, union, or enum type directly, prefix it with
 struct_, union_, or enum_, as in C.struct_stat.
@@ -68,6 +69,21 @@ C compilers are aware of this calling convention and adjust
 the call accordingly, but Go cannot.  In Go, you must pass
 the pointer to the first element explicitly: C.f(&x[0]).
 
+A few special functions convert between Go and C types
+by making copies of the data.  In pseudo-Go definitions:
+
+	// Go string to C string
+	func C.CString(string) *C.char
+
+	// C string to Go string
+	func C.GoString(*C.char) string
+
+	// C string, length to Go string
+	func C.GoStringN(*C.char, C.int) string
+
+	// C pointer, length to Go []byte
+	func C.GoBytes(unsafe.Pointer, C.int) []byte
+
 Cgo transforms the input file into four output files: two Go source
 files, a C file for 6c (or 8c or 5c), and a C file for gcc.
 
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index a4d83f1e7..7ec4d8ccf 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -1140,6 +1140,14 @@ func (c *typeConv) Type(dtype dwarf.Type) *Type {
 			t.Align = c.ptrSize
 			break
 		}
+		if dt.Name == "_GoBytes_" {
+			// Special C name for Go []byte type.
+			// Knows slice layout used by compilers: pointer, length, cap.
+			t.Go = c.Ident("[]byte")
+			t.Size = c.ptrSize + 4 + 4
+			t.Align = c.ptrSize
+			break
+		}
 		name := c.Ident("_Ctypedef_" + dt.Name)
 		t.Go = name // publish before recursive call
 		sub := c.Type(dt.Type)
diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index 6802dd1cf..9c962b8ff 100644
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -236,7 +236,7 @@ func (p *Package) writeDefsFunc(fc, fgo2 *os.File, n *Name) {
 	printer.Fprint(fgo2, fset, d)
 	fmt.Fprintf(fgo2, "\n")
 
-	if name == "CString" || name == "GoString" || name == "GoStringN" {
+	if name == "CString" || name == "GoString" || name == "GoStringN" || name == "GoBytes" {
 		// The builtins are already defined in the C prolog.
 		return
 	}
@@ -316,7 +316,7 @@ func (p *Package) writeOutput(f *File, srcfile string) {
 
 func (p *Package) writeOutputFunc(fgcc *os.File, n *Name) {
 	name := n.Mangle
-	if name == "_Cfunc_CString" || name == "_Cfunc_GoString" || name == "_Cfunc_GoStringN" || p.Written[name] {
+	if name == "_Cfunc_CString" || name == "_Cfunc_GoString" || name == "_Cfunc_GoStringN" || name == "_Cfunc_GoBytes" || p.Written[name] {
 		// The builtins are already defined in the C prolog, and we don't
 		// want to duplicate function definitions we've already done.
 		return
@@ -412,7 +412,7 @@ func (p *Package) writeExports(fgo2, fc, fm *os.File) {
 				t := p.cgoType(atype)
 				if off%t.Align != 0 {
 					pad := t.Align - off%t.Align
-					ctype += fmt.Sprintf("\t\tchar __pad%d[%d]\n", npad, pad)
+					ctype += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad)
 					off += pad
 					npad++
 				}
@@ -646,6 +646,8 @@ func (p *Package) cgoType(e ast.Expr) *Type {
 			}
 			return r
 		}
+		error(e.Pos(), "unrecognized Go type %s", t.Name)
+		return &Type{Size: 4, Align: 4, C: c("int")}
 	case *ast.SelectorExpr:
 		id, ok := t.X.(*ast.Ident)
 		if ok && id.Name == "unsafe" && t.Sel.Name == "Pointer" {
@@ -679,8 +681,10 @@ __cgo_size_assert(double, 8)
 
 const builtinProlog = `
 typedef struct { char *p; int n; } _GoString_;
+typedef struct { char *p; int n; int c; } _GoBytes_;
 _GoString_ GoString(char *p);
 _GoString_ GoStringN(char *p, int l);
+_GoBytes_ GoBytes(void *p, int n);
 char *CString(_GoString_);
 `
 
@@ -705,10 +709,17 @@ void
 }
 
 void
+·_Cfunc_GoBytes(int8 *p, int32 l, Slice s)
+{
+	s = runtime·gobytes((byte*)p, l);
+	FLUSH(&s);
+}
+
+void
 ·_Cfunc_CString(String s, int8 *p)
 {
 	p = runtime·cmalloc(s.len+1);
-	runtime·mcpy((byte*)p, s.str, s.len);
+	runtime·memmove((byte*)p, s.str, s.len);
 	p[s.len] = 0;
 	FLUSH(&p);
 }