[ms-inline asm] Add a very simple test case.  Basically, we're only testing for
crashers at the moment (and coincidentally this case was causing a crash).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161520 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index a8a06a9..be90578 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -2786,6 +2786,9 @@
                                     SourceLocation AsmLoc,
                                     ArrayRef<Token> AsmToks,
                                     const TargetInfo &TI) {
+  if (!AsmToks.size())
+    return "";
+
   std::string Res;
   IdentifierInfo *II = AsmToks[0].getIdentifierInfo();
   Res = II->getName().str();
@@ -2841,6 +2844,9 @@
 static std::string buildMSAsmString(Sema &SemaRef,
                                     ArrayRef<Token> AsmToks,
                                     ArrayRef<unsigned> LineEnds) {
+  if (!AsmToks.size())
+    return "";
+
   // Collect the tokens into a string
   SmallString<512> Asm;
   SmallString<512> TokenBuf;
diff --git a/test/CodeGen/ms-inline-asm.c b/test/CodeGen/ms-inline-asm.c
new file mode 100644
index 0000000..2d36bbc
--- /dev/null
+++ b/test/CodeGen/ms-inline-asm.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -O0 -fms-extensions -w -emit-llvm -o - | FileCheck %s
+
+void t1() {
+// CHECK: @t1
+// CHECK: ret void
+  __asm {}
+}