r316528 - Correct behavior of fastcall when default CC is set.

Erich Keane via cfe-commits cfe-commits at lists.llvm.org
Tue Oct 24 16:12:01 PDT 2017

Author: erichkeane
Date: Tue Oct 24 16:12:01 2017
New Revision: 316528

URL: http://llvm.org/viewvc/llvm-project?rev=316528&view=rev
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.


Modified: cfe/trunk/lib/AST/ASTContext.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=316528&r1=316527&r2=316528&view=diff
--- cfe/trunk/lib/AST/ASTContext.cpp (original)
+++ cfe/trunk/lib/AST/ASTContext.cpp Tue Oct 24 16:12:01 2017
@@ -9269,7 +9269,7 @@ CallingConv ASTContext::getDefaultCallin
   case LangOptions::DCC_CDecl:
     return CC_C;
   case LangOptions::DCC_FastCall:
-    if (getTargetInfo().hasFeature("sse2"))
+    if (getTargetInfo().hasFeature("sse2") && !IsVariadic)
       return CC_X86FastCall;
   case LangOptions::DCC_StdCall:

Modified: cfe/trunk/test/CodeGenCXX/default_calling_conv.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/default_calling_conv.cpp?rev=316528&r1=316527&r2=316528&view=diff
--- cfe/trunk/test/CodeGenCXX/default_calling_conv.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/default_calling_conv.cpp Tue Oct 24 16:12:01 2017
@@ -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() {}

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