From 5c484035ac41e9af5907ec574faa6e8c43cc00a2 Mon Sep 17 00:00:00 2001
From: Erich Keane <erich.keane@intel.com>
Date: Tue, 24 Oct 2017 23:12:01 +0000
Subject: [PATCH] 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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@316528 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/AST/ASTContext.cpp | 2 +-
test/CodeGenCXX/default_calling_conv.cpp | 7 +++++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index a7ff9e10e9d..87d096dab00 100644
--- a/lib/AST/ASTContext.cpp
+++ b/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/test/CodeGenCXX/default_calling_conv.cpp b/test/CodeGenCXX/default_calling_conv.cpp
index 95c214a223d..15eedc8e318 100644
--- a/test/CodeGenCXX/default_calling_conv.cpp
+++ b/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() {}
--
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