From 130a2eecc44b762345d5ff704e9d599b25e0f091 Mon Sep 17 00:00:00 2001
From: eric_tian <eric_tian@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Fri, 8 May 2009 02:27:46 +0000
Subject: [PATCH] =?UTF-8?q?The=20GCC=20compiler=E2=80=99s=20behavior=20is?=
 =?UTF-8?q?=20different=20than=20the=20Microsoft=20compilers=20for=20stati?=
 =?UTF-8?q?cally=20linked=20vararg=20functions.=20The=20GCC=20compilers=20?=
 =?UTF-8?q?do=20provide=20=5F=5Fbuiltin=5F=20functions=20for=20accessing?=
 =?UTF-8?q?=20varargs.=20we=20should=20use=20these=20intrinsic=20functions?=
 =?UTF-8?q?=20with=20GCC?=
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git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8260 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdePkg/Include/Base.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/MdePkg/Include/Base.h b/MdePkg/Include/Base.h
index 00cce609f5..69ebba345e 100644
--- a/MdePkg/Include/Base.h
+++ b/MdePkg/Include/Base.h
@@ -332,7 +332,20 @@ struct _LIST_ENTRY {
 //    return Result
 //  }
 //
+#if defined(__GNUC__)
+//
+//  In GCC compiler, its behavior for statically linked varargs is different with MSFT tool chain.
+//  Should use __builtin_* intrinsic functions provided by GCC compiler to access varargs.
+//
+typedef __builtin_va_list VA_LIST;
 
+#define VA_START(Marker, Parameter)  __builtin_va_start(Marker, Parameter)
+
+#define VA_ARG(Marker, TYPE)         __builtin_va_arg(Marker, TYPE)
+
+#define VA_END(Marker)               __builtin_va_end(Marker)
+
+#else
 /**
   Return the size of argument that has been aligned to sizeof (UINTN).
 
@@ -394,6 +407,8 @@ typedef CHAR8 *VA_LIST;
 **/
 #define VA_END(Marker)      (Marker = (VA_LIST) 0)
 
+#endif
+
 /**
   Macro that returns the byte offset of a field in a data structure.