cmd/fix,cmd/cgo,misc/cgo: map the EGLDisplay C type to uintptr in Go

Similar to to macOS' CF* types and JNI's jobject and derived types,
the EGLDisplay type is declared as a pointer but can contain
non-pointers (see #27054).
Fix it the same way: map EGLDisplay to uintptr in Go.

Fixes #27054

RELNOTE=yes

Change-Id: I6136f8f8162687c5493b30ed324e29efe55a8fd7
Reviewed-on: https://go-review.googlesource.com/c/154417
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

misc/cgo/test/issue27054/egl.h

@@ -0,0 +1,7 @@
+// 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.
+
+// This is the relevant part of EGL/egl.h.
+
+typedef void *EGLDisplay;

misc/cgo/test/issue27054/test27054.go

@@ -0,0 +1,17 @@
+// 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.
+
+package issue27054
+
+/*
+#include "egl.h"
+*/
+import "C"
+import (
+	"testing"
+)
+
+func Test27054(t *testing.T) {
+	var _ C.EGLDisplay = 0 // Note: 0, not nil. That makes sure we use uintptr for this type.
+}

src/cmd/cgo/gcc.go

@@ -3004,6 +3004,9 @@ func (c *typeConv) badPointerTypedef(dt *dwarf.TypedefType) bool {
 	if c.badJNI(dt) {
 		return true
 	}
+	if c.badEGLDisplay(dt) {
+		return true
+	}
 	return false
 }
 
@@ -3140,6 +3143,19 @@ func (c *typeConv) badJNI(dt *dwarf.TypedefType) bool {
 	return false
 }
 
+func (c *typeConv) badEGLDisplay(dt *dwarf.TypedefType) bool {
+	if dt.Name != "EGLDisplay" {
+		return false
+	}
+	// Check that the typedef is "typedef void *EGLDisplay".
+	if ptr, ok := dt.Type.(*dwarf.PtrType); ok {
+		if _, ok := ptr.Type.(*dwarf.VoidType); ok {
+			return true
+		}
+	}
+	return false
+}
+
 // jniTypes maps from JNI types that we want to be uintptrs, to the underlying type to which
 // they are mapped. The base "jobject" maps to the empty string.
 var jniTypes = map[string]string{

src/cmd/fix/egltype.go

@@ -0,0 +1,32 @@
+// 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.
+
+package main
+
+import (
+	"go/ast"
+)
+
+func init() {
+	register(eglFix)
+}
+
+var eglFix = fix{
+	name:     "egl",
+	date:     "2018-12-15",
+	f:        eglfix,
+	desc:     `Fixes initializers of EGLDisplay`,
+	disabled: false,
+}
+
+// Old state:
+//   type EGLDisplay unsafe.Pointer
+// New state:
+//   type EGLDisplay uintptr
+// This fix finds nils initializing these types and replaces the nils with 0s.
+func eglfix(f *ast.File) bool {
+	return typefix(f, func(s string) bool {
+		return s == "C.EGLDisplay"
+	})
+}

src/cmd/fix/egltype_test.go

@@ -0,0 +1,185 @@
+// Copyright 2017 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.
+
+package main
+
+func init() {
+	addTestCases(eglTests, eglfix)
+}
+
+var eglTests = []testCase{
+	{
+		Name: "egl.localVariable",
+		In: `package main
+
+import "C"
+
+func f() {
+	var x C.EGLDisplay = nil
+	x = nil
+	x, x = nil, nil
+}
+`,
+		Out: `package main
+
+import "C"
+
+func f() {
+	var x C.EGLDisplay = 0
+	x = 0
+	x, x = 0, 0
+}
+`,
+	},
+	{
+		Name: "egl.globalVariable",
+		In: `package main
+
+import "C"
+
+var x C.EGLDisplay = nil
+
+func f() {
+	x = nil
+}
+`,
+		Out: `package main
+
+import "C"
+
+var x C.EGLDisplay = 0
+
+func f() {
+	x = 0
+}
+`,
+	},
+	{
+		Name: "egl.EqualArgument",
+		In: `package main
+
+import "C"
+
+var x C.EGLDisplay
+var y = x == nil
+var z = x != nil
+`,
+		Out: `package main
+
+import "C"
+
+var x C.EGLDisplay
+var y = x == 0
+var z = x != 0
+`,
+	},
+	{
+		Name: "egl.StructField",
+		In: `package main
+
+import "C"
+
+type T struct {
+	x C.EGLDisplay
+}
+
+var t = T{x: nil}
+`,
+		Out: `package main
+
+import "C"
+
+type T struct {
+	x C.EGLDisplay
+}
+
+var t = T{x: 0}
+`,
+	},
+	{
+		Name: "egl.FunctionArgument",
+		In: `package main
+
+import "C"
+
+func f(x C.EGLDisplay) {
+}
+
+func g() {
+	f(nil)
+}
+`,
+		Out: `package main
+
+import "C"
+
+func f(x C.EGLDisplay) {
+}
+
+func g() {
+	f(0)
+}
+`,
+	},
+	{
+		Name: "egl.ArrayElement",
+		In: `package main
+
+import "C"
+
+var x = [3]C.EGLDisplay{nil, nil, nil}
+`,
+		Out: `package main
+
+import "C"
+
+var x = [3]C.EGLDisplay{0, 0, 0}
+`,
+	},
+	{
+		Name: "egl.SliceElement",
+		In: `package main
+
+import "C"
+
+var x = []C.EGLDisplay{nil, nil, nil}
+`,
+		Out: `package main
+
+import "C"
+
+var x = []C.EGLDisplay{0, 0, 0}
+`,
+	},
+	{
+		Name: "egl.MapKey",
+		In: `package main
+
+import "C"
+
+var x = map[C.EGLDisplay]int{nil: 0}
+`,
+		Out: `package main
+
+import "C"
+
+var x = map[C.EGLDisplay]int{0: 0}
+`,
+	},
+	{
+		Name: "egl.MapValue",
+		In: `package main
+
+import "C"
+
+var x = map[int]C.EGLDisplay{0: nil}
+`,
+		Out: `package main
+
+import "C"
+
+var x = map[int]C.EGLDisplay{0: 0}
+`,
+	},
+}