[ms-inline asm] Add basic codegen support for simple asm stmts. Currently,

only machine specific clobbers are modeled.

llvm-svn: 161524

clang/lib/CodeGen/CGStmt.cpp

@@ -1686,4 +1686,19 @@ void CodeGenFunction::EmitMSAsmStmt(const MSAsmStmt &S) {
   // MS-style inline assembly is not fully supported, so sema emits a warning.
   if (!CGM.getCodeGenOpts().EmitMicrosoftInlineAsm)
     return;
+
+  assert (S.isSimple() && "CodeGen can only handle simple MSAsmStmts.");
+
+  std::vector<llvm::Value*> Args;
+  std::vector<llvm::Type *> ArgTypes;
+
+  std::string MachineClobbers = Target.getClobbers();
+
+  llvm::FunctionType *FTy =
+    llvm::FunctionType::get(VoidTy, ArgTypes, false);
+
+  llvm::InlineAsm *IA =
+    llvm::InlineAsm::get(FTy, *S.getAsmString(), MachineClobbers, true);
+  llvm::CallInst *Result = Builder.CreateCall(IA, Args);
+  Result->addAttribute(~0, llvm::Attribute::NoUnwind);
 }

clang/test/CodeGen/ms-inline-asm.c

@@ -1,7 +1,8 @@
-// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -O0 -fms-extensions -w -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -O0 -fms-extensions -fenable-experimental-ms-inline-asm -w -emit-llvm -o - | FileCheck %s
 
 void t1() {
 // CHECK: @t1
+// CHECK: call void asm sideeffect "", "~{dirflag},~{fpsr},~{flags}"() nounwind
 // CHECK: ret void
   __asm {}
 }