Correct behavior of fastcall when default CC is set.

Fastcall doesn't support variadic function calls, so
setting the default calling convention to Fastcall would
result in incorrect code being emitted for these conditions.

This patch adds a 'variadic' test to the default calling conv
test, as well as fixes the behavior of fastcall.

llvm-svn: 316528

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index a7ff9e1..87d096d 100644 (file)
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -9269,7 +9269,7 @@ CallingConv ASTContext::getDefaultCallingConvention(bool IsVariadic,
   case LangOptions::DCC_CDecl:
     return CC_C;
   case LangOptions::DCC_FastCall:
-    if (getTargetInfo().hasFeature("sse2"))
+    if (getTargetInfo().hasFeature("sse2") && !IsVariadic)
       return CC_X86FastCall;
     break;
   case LangOptions::DCC_StdCall:

diff --git a/clang/test/CodeGenCXX/default_calling_conv.cpp b/clang/test/CodeGenCXX/default_calling_conv.cpp
index 95c214a..15eedc8 100644 (file)
--- a/clang/test/CodeGenCXX/default_calling_conv.cpp
+++ b/clang/test/CodeGenCXX/default_calling_conv.cpp
@@ -10,6 +10,13 @@
 // VECTORCALL: define x86_vectorcallcc void @_Z5test1v
 void test1() {}
 
+// fastcall, stdcall, and vectorcall all do not support variadic functions.
+// CDECL: define void @_Z12testVariadicz
+// FASTCALL: define void @_Z12testVariadicz
+// STDCALL: define void @_Z12testVariadicz
+// VECTORCALL: define void @_Z12testVariadicz
+void testVariadic(...){}
+
 // ALL: define void @_Z5test2v
 void __attribute__((cdecl)) test2() {}