Mangle C struct fields that happen to be named after Go keywords by prefixing them...

Fixes #36.

R=rsc
https://golang.org/cl/157061

diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 79dcd29a9657ac39500f906e24aa5f83749b4f78..5f3653976df4f3fa964a14265acabd858b998324 100644 (file)
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -619,6 +619,34 @@ func (c *typeConv) Struct(dt *dwarf.StructType) (expr *ast.StructType, csyntax s
        csyntax = "struct { ";
        fld := make([]*ast.Field, 0, 2*len(dt.Field)+1);        // enough for padding around every field
        off := int64(0);
+
+       // Mangle struct fields that happen to be named Go keywords into
+       // _{keyword}.  Create a map from C ident -> Go ident.  The Go ident will
+       // be mangled.  Any existing identifier that already has the same name on
+       // the C-side will cause the Go-mangled version to be prefixed with _.
+       // (e.g. in a struct with fields '_type' and 'type', the latter would be
+       // rendered as '__type' in Go).
+       ident := make(map[string]string);
+       used := make(map[string]bool);
+       for _, f := range dt.Field {
+               ident[f.Name] = f.Name;
+               used[f.Name] = true;
+       }
+       for cid, goid := range ident {
+               if token.Lookup(strings.Bytes(goid)).IsKeyword() {
+                       // Avoid keyword
+                       goid = "_" + goid;
+
+                       // Also avoid existing fields
+                       for _, exist := used[goid]; exist; _, exist = used[goid] {
+                               goid = "_" + goid
+                       }
+
+                       used[goid] = true;
+                       ident[cid] = goid;
+               }
+       }
+
        for _, f := range dt.Field {
                if f.ByteOffset > off {
                        fld = c.pad(fld, f.ByteOffset-off);
@@ -627,7 +655,8 @@ func (c *typeConv) Struct(dt *dwarf.StructType) (expr *ast.StructType, csyntax s
                t := c.Type(f.Type);
                n := len(fld);
                fld = fld[0 : n+1];
-               fld[n] = &ast.Field{Names: []*ast.Ident{c.Ident(f.Name)}, Type: t.Go};
+
+               fld[n] = &ast.Field{Names: []*ast.Ident{c.Ident(ident[f.Name])}, Type: t.Go};
                off += t.Size;
                csyntax += t.C + " " + f.Name + "; ";
                if t.Align > align {