cmd/cgo: mangle names before rewriting calls

Move name mangling before rewriting calls rather than after.
This is in preparation for later changes.

Change-Id: I74bc351f4290dad7ebf6d0d361bb684087786053
Reviewed-on: https://go-review.googlesource.com/c/142881
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/cgo/gcc.go

@@ -188,6 +188,7 @@ func (p *Package) Translate(f *File) {
 			break
 		}
 	}
+	p.prepareNames(f)
 	if p.rewriteCalls(f) {
 		// Add `import _cgo_unsafe "unsafe"` after the package statement.
 		f.Edit.Insert(f.offset(f.AST.Name.End()), "; import _cgo_unsafe \"unsafe\"")
@@ -679,6 +680,27 @@ func (p *Package) recordTypedefs1(dtype dwarf.Type, visited map[dwarf.Type]bool)
 	}
 }
 
+// prepareNames finalizes the Kind field of not-type names and sets
+// the mangled name of all names.
+func (p *Package) prepareNames(f *File) {
+	for _, n := range f.Name {
+		if n.Kind == "not-type" {
+			if n.Define == "" {
+				n.Kind = "var"
+			} else {
+				n.Kind = "macro"
+				n.FuncType = &FuncType{
+					Result: n.Type,
+					Go: &ast.FuncType{
+						Results: &ast.FieldList{List: []*ast.Field{{Type: n.Type.Go}}},
+					},
+				}
+			}
+		}
+		p.mangleName(n)
+	}
+}
+
 // mangleName does name mangling to translate names
 // from the original Go source files to the names
 // used in the final Go files generated by cgo.
@@ -1130,24 +1152,7 @@ func (p *Package) rewriteRef(f *File) {
 	// code for them.
 	functions := make(map[string]bool)
 
-	// Assign mangled names.
 	for _, n := range f.Name {
-		if n.Kind == "not-type" {
-			if n.Define == "" {
-				n.Kind = "var"
-			} else {
-				n.Kind = "macro"
-				n.FuncType = &FuncType{
-					Result: n.Type,
-					Go: &ast.FuncType{
-						Results: &ast.FieldList{List: []*ast.Field{{Type: n.Type.Go}}},
-					},
-				}
-			}
-		}
-		if n.Mangle == "" {
-			p.mangleName(n)
-		}
 		if n.Kind == "func" {
 			functions[n.Go] = false
 		}