Make IPC_MESSAGE_EXPORT more robust.
Currently, files that want to export ipc messages currently do
#undef IPC_MESSAGE_EXPORT
#define IPC_MESSAGE_EXPORT CONTENT_EXPORT
at the top, and files that don't want to export ipc messages just do nothing. This is problematic if a cc file does
#include "exported_messages.h"
#include "not_exported_messages.h"
because the second header file picks up the #define from the first file and declares all its messages as exported. In other translation units, where not_exported_messages.h is #included without another header above it, the messages will get default visibility – so the same class ends up with different visibilities in different translation units.
Instead, let ipc_message_macros.h #undef IPC_MESSAGE_EXPORT outside of the include guard, so that all files that don't set the define see it as defined to nothing. (Idea from jam@)
Also disable about:ipc in the component build, since ipc logging adds a dependency from chrome on all ipc message classes, so they would all have to be exported.
BUG=90078
TEST=No linker errors about IPC messages when doing components build on mac. (Other linker errors remain for now.)
TBR=brettw
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=122689
Review URL: http://codereview.chromium.org/9425006
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122828 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ipc/ipc_message_macros.h b/ipc/ipc_message_macros.h
index 783108ea..f37c05b 100644
--- a/ipc/ipc_message_macros.h
+++ b/ipc/ipc_message_macros.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
@@ -173,6 +173,14 @@
// ViewHostMsg_SyncMessageName::WriteReplyParams(reply_msg, out1, out2);
// Send(reply_msg);
+// Files that want to export their ipc messages should do
+// #undef IPC_MESSAGE_EXPORT
+// #define IPC_MESSAGE_EXPORT VISIBILITY_MACRO
+// after including this header, but before using any of the macros below.
+// (This needs to be before the include guard.)
+#undef IPC_MESSAGE_EXPORT
+#define IPC_MESSAGE_EXPORT
+
#ifndef IPC_IPC_MESSAGE_MACROS_H_
#define IPC_IPC_MESSAGE_MACROS_H_
@@ -184,11 +192,6 @@
#include "ipc/ipc_message_utils_impl.h"
#endif
-// Override this to force message classes to be exported.
-#ifndef IPC_MESSAGE_EXPORT
-#define IPC_MESSAGE_EXPORT
-#endif
-
// Macros for defining structs. May be subsequently redefined.
#define IPC_STRUCT_BEGIN(struct_name) \
IPC_STRUCT_BEGIN_WITH_PARENT(struct_name, IPC::NoParams)
