cmd/cgo: fix cgo bad typedefs

Two fixes:

1) Typedefs of the bad typedefs should also not be rewritten to the
   underlying type.  They shouldn't just be uintptr, though, they should
   retain the C naming structure.  For example, in C:

   typedef const __CFString * CFStringRef;
   typedef CFStringRef SecKeyAlgorithm;

   we want the Go:

   type _Ctype_CFStringRef uintptr
   type _Ctype_SecKeyAlgorithm = _Ctype_CFStringRef

2) We need more types than just function arguments/return values.
   At least we need types of global variables, so when we see a reference to:

   extern const SecKeyAlgorithm kSecKeyAlgorithmECDSASignatureDigestX962SHA1;

   we know that we need to investigate the type SecKeyAlgorithm.
   Might as well just find every typedef and check the badness of all of them.
   This requires looping until a fixed point of known types is reached.
   Usually it takes just 2 iterations, sometimes 3.

Fixes #24161

Change-Id: I32ca7e48eb4d4133c6242e91d1879636f5224ea9
Reviewed-on: https://go-review.googlesource.com/123177
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

4 files changed, 98 insertions, 0 deletions

diff --git a/misc/cgo/test/issue24161_darwin_test.go b/misc/cgo/test/issue24161_darwin_test.go
index cb15b3c5a0..10fdfbd1bc 100644
--- a/misc/cgo/test/issue24161_darwin_test.go
+++ b/misc/cgo/test/issue24161_darwin_test.go
@@ -8,6 +8,9 @@ import (
 	"testing"
 
 	"./issue24161arg"
+	"./issue24161e0"
+	"./issue24161e1"
+	"./issue24161e2"
 	"./issue24161res"
 )
 
@@ -17,3 +20,12 @@ func Test24161Arg(t *testing.T) {
 func Test24161Res(t *testing.T) {
 	issue24161res.Test(t)
 }
+func Test24161Example0(t *testing.T) {
+	issue24161e0.Test(t)
+}
+func Test24161Example1(t *testing.T) {
+	issue24161e1.Test(t)
+}
+func Test24161Example2(t *testing.T) {
+	issue24161e2.Test(t)
+}
diff --git a/misc/cgo/test/issue24161e0/main.go b/misc/cgo/test/issue24161e0/main.go
new file mode 100644
index 0000000000..ec5bea9662
--- /dev/null
+++ b/misc/cgo/test/issue24161e0/main.go
@@ -0,0 +1,22 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin
+
+package issue24161e0
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework CoreFoundation -framework Security
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/Security.h>
+*/
+import "C"
+import "testing"
+
+func f1() {
+	C.SecKeyCreateSignature(0, C.kSecKeyAlgorithmECDSASignatureDigestX962SHA1, 0, nil)
+}
+
+func Test(t *testing.T) {}
diff --git a/misc/cgo/test/issue24161e1/main.go b/misc/cgo/test/issue24161e1/main.go
new file mode 100644
index 0000000000..aea0ff50c5
--- /dev/null
+++ b/misc/cgo/test/issue24161e1/main.go
@@ -0,0 +1,31 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin
+
+package issue24161e1
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework CoreFoundation -framework Security
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/Security.h>
+*/
+import "C"
+import (
+	"fmt"
+	"testing"
+)
+
+func f1() {
+	C.SecKeyCreateSignature(0, C.kSecKeyAlgorithmECDSASignatureDigestX962SHA1, 0, nil)
+}
+
+func f2(e C.CFErrorRef) {
+	if desc := C.CFErrorCopyDescription(e); desc != 0 {
+		fmt.Println(desc)
+	}
+}
+
+func Test(t *testing.T) {}
diff --git a/misc/cgo/test/issue24161e2/main.go b/misc/cgo/test/issue24161e2/main.go
new file mode 100644
index 0000000000..c6675a7689
--- /dev/null
+++ b/misc/cgo/test/issue24161e2/main.go
@@ -0,0 +1,33 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin
+
+package issue24161e2
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework CoreFoundation -framework Security
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/Security.h>
+*/
+import "C"
+import (
+	"fmt"
+	"testing"
+)
+
+var _ C.CFStringRef
+
+func f1() {
+	C.SecKeyCreateSignature(0, C.kSecKeyAlgorithmECDSASignatureDigestX962SHA1, 0, nil)
+}
+
+func f2(e C.CFErrorRef) {
+	if desc := C.CFErrorCopyDescription(e); desc != 0 {
+		fmt.Println(desc)
+	}
+}
+
+func Test(t *testing.T) {}