From 08e46f97ec8c00cc1bfe87fcd014db211a878ffb Mon Sep 17 00:00:00 2001
From: Nico Weber <nicolasweber@gmx.de>
Date: Tue, 24 Apr 2012 21:27:01 +0000
Subject: [PATCH] Let NULL and MSVC headers coexist better.
Fixes the two issues mentioned in PR12146.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155490 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Headers/stddef.h | 9 ++++++---
test/Headers/ms-null-ms-header-vs-stddef.cpp | 16 ++++++++++++++++
2 files changed, 22 insertions(+), 3 deletions(-)
create mode 100644 test/Headers/ms-null-ms-header-vs-stddef.cpp
diff --git a/lib/Headers/stddef.h b/lib/Headers/stddef.h
index 9e87ee89b3b..d7db826e676 100644
--- a/lib/Headers/stddef.h
+++ b/lib/Headers/stddef.h
@@ -43,10 +43,13 @@ typedef __WCHAR_TYPE__ wchar_t;
#undef NULL
#ifdef __cplusplus
-#undef __null // VC++ hack.
-#define NULL __null
+# if !defined(__MINGW32__) && !defined(_MSC_VER)
+# define NULL __null
+# else
+# define NULL 0
+# endif
#else
-#define NULL ((void*)0)
+# define NULL ((void*)0)
#endif
#define offsetof(t, d) __builtin_offsetof(t, d)
diff --git a/test/Headers/ms-null-ms-header-vs-stddef.cpp b/test/Headers/ms-null-ms-header-vs-stddef.cpp
new file mode 100644
index 00000000000..7efa871da90
--- /dev/null
+++ b/test/Headers/ms-null-ms-header-vs-stddef.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang -fsyntax-only -target i686-pc-win32 %s
+// RUN: %clang -fsyntax-only -target i386-mingw32 %s
+
+// Something in MSVC's headers (pulled in e.g. by <crtdefs.h>) defines __null
+// to something, mimick that.
+#define __null
+
+#include <stddef.h>
+
+// __null is used as a type annotation in MS headers, with __null defined to
+// nothing in regular builds. This should continue to work even with stddef.h
+// included.
+void f(__null void* p) { }
+
+// NULL should work fine even with __null defined to nothing.
+void* p = NULL;
--
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