From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Mon, 1 Aug 2016 21:31:24 +0000 (+0000)
Subject: CodeGen: simplify the CC handling for TLS wrappers
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=56057abaa37e14ff41af046d6b684f295956e154;p=clang

CodeGen: simplify the CC handling for TLS wrappers

Use the calling convention of the wrapper directly to set the calling convention
to ensure that the calling convention matches.  Incorrectly setting the calling
convention results in the code path being entirely nullified as InstCombine +
SimplifyCFG will prune the mismatched CC calls.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@277390 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index 36eb40ef09..2492c82f86 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2346,8 +2346,7 @@ LValue ItaniumCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
   llvm::Function *Wrapper = getOrCreateThreadLocalWrapper(VD, Val);
 
   llvm::CallInst *CallVal = CGF.Builder.CreateCall(Wrapper);
-  if (isThreadWrapperReplaceable(VD, CGF.CGM))
-    CallVal->setCallingConv(llvm::CallingConv::CXX_FAST_TLS);
+  CallVal->setCallingConv(Wrapper->getCallingConv());
 
   LValue LV;
   if (VD->getType()->isReferenceType())
diff --git a/test/CodeGen/windows-on-arm-itanium-thread-local.c b/test/CodeGen/windows-on-arm-itanium-thread-local.c
new file mode 100644
index 0000000000..7f12c367d9
--- /dev/null
+++ b/test/CodeGen/windows-on-arm-itanium-thread-local.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple thumbv7--windows-itanium -fdeclspec -fms-compatibility -fms-compatibility-version=19.0 -S -emit-llvm -o - %s | FileCheck %s
+
+__declspec(thread) static void *c;
+void f(void *p) {
+  c = p;
+}
+
+// CHECK-LABEL: @f(i8* %p)
+// CHECK-NOT: call i8** @_ZTWL1c()
+// CHECK: call arm_aapcs_vfpcc i8** @_ZTWL1c()
+