From 9536480edc5f29368d2b7a05e30c199630b8074e Mon Sep 17 00:00:00 2001
From: Joel Sing <jsing@google.com>
Date: Thu, 20 Sep 2012 13:20:33 +1000
Subject: [PATCH] cgo: process DWARF info even when debug data is used for
 value

Always process the DWARF info, even when the const value is determined
using the debug data block. This ensures that the injected enum is
removed and future loads of the same constant do not trigger
inconsistent definitions.

Add tests for issues 2470 and 4054.
Fixes #4054.

R=golang-dev, fullung, dave, rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6501101
---
 misc/cgo/test/basic.go      | 10 ++++++++++
 misc/cgo/test/cgo_test.go   |  1 +
 misc/cgo/test/issue4054a.go | 23 +++++++++++++++++++++++
 misc/cgo/test/issue4054b.go | 23 +++++++++++++++++++++++
 src/cmd/cgo/gcc.go          |  9 +++++----
 5 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 misc/cgo/test/issue4054a.go
 create mode 100644 misc/cgo/test/issue4054b.go

diff --git a/misc/cgo/test/basic.go b/misc/cgo/test/basic.go
index 3716a4062eb..0c91801696e 100644
--- a/misc/cgo/test/basic.go
+++ b/misc/cgo/test/basic.go
@@ -14,6 +14,7 @@ package cgotest
 
 #define SHIFT(x, y)  ((x)<<(y))
 #define KILO SHIFT(1, 10)
+#define UINT32VAL 0xc008427bU
 
 enum E {
 	Enum1 = 1,
@@ -141,3 +142,12 @@ func benchCgoCall(b *testing.B) {
 		C.add(x, y)
 	}
 }
+
+// Issue 2470.
+func testUnsignedInt(t *testing.T) {
+	a := (int64)(C.UINT32VAL)
+	b := (int64)(0xc008427b)
+	if a != b {
+		t.Errorf("Incorrect unsigned int - got %x, want %x", a, b)
+	}
+}
diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index c3c35b53c2f..3b866290fe2 100644
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -16,6 +16,7 @@ func TestEnum(t *testing.T)                { testEnum(t) }
 func TestAtol(t *testing.T)                { testAtol(t) }
 func TestErrno(t *testing.T)               { testErrno(t) }
 func TestMultipleAssign(t *testing.T)      { testMultipleAssign(t) }
+func TestUnsignedInt(t *testing.T)         { testUnsignedInt(t) }
 func TestCallback(t *testing.T)            { testCallback(t) }
 func TestCallbackGC(t *testing.T)          { testCallbackGC(t) }
 func TestCallbackPanic(t *testing.T)       { testCallbackPanic(t) }
diff --git a/misc/cgo/test/issue4054a.go b/misc/cgo/test/issue4054a.go
new file mode 100644
index 00000000000..2abdac59047
--- /dev/null
+++ b/misc/cgo/test/issue4054a.go
@@ -0,0 +1,23 @@
+// Copyright 2012 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 cgotest
+
+/*
+typedef enum {
+	A = 0,
+	B,
+	C,
+	D,
+	E,
+	F,
+	G,
+	H,
+	I,
+	J,
+} issue4054a;
+*/
+import "C"
+
+var issue4054a = []int{C.A, C.B, C.C, C.D, C.E, C.F, C.G, C.H, C.I, C.J}
diff --git a/misc/cgo/test/issue4054b.go b/misc/cgo/test/issue4054b.go
new file mode 100644
index 00000000000..048964c8937
--- /dev/null
+++ b/misc/cgo/test/issue4054b.go
@@ -0,0 +1,23 @@
+// Copyright 2012 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 cgotest
+
+/*
+typedef enum {
+	A = 0,
+	B,
+	C,
+	D,
+	E,
+	F,
+	G,
+	H,
+	I,
+	J,
+} issue4054b;
+*/
+import "C"
+
+var issue4054b = []int{C.A, C.B, C.C, C.D, C.E, C.F, C.G, C.H, C.I, C.J}
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 2aaa570d830..d16d0202f66 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -616,10 +616,7 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
 			n.FuncType = conv.FuncType(f, pos)
 		} else {
 			n.Type = conv.Type(types[i], pos)
-			// Prefer debug data over DWARF debug output, if we have it.
-			if n.Kind == "const" && i < len(enumVal) {
-				n.Const = fmt.Sprintf("%#x", enumVal[i])
-			} else if enums[i] != 0 && n.Type.EnumValues != nil {
+			if enums[i] != 0 && n.Type.EnumValues != nil {
 				k := fmt.Sprintf("__cgo_enum__%d", i)
 				n.Kind = "const"
 				n.Const = fmt.Sprintf("%#x", n.Type.EnumValues[k])
@@ -627,6 +624,10 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
 				// equally in future loads of the same constant.
 				delete(n.Type.EnumValues, k)
 			}
+			// Prefer debug data over DWARF debug output, if we have it.
+			if n.Kind == "const" && i < len(enumVal) {
+				n.Const = fmt.Sprintf("%#x", enumVal[i])
+			}
 		}
 	}