Some autoconf tests use module level inline asm to test compiler's handling of

.cfi_startproc. e.g. libffi:

 $ cat confopt.c 
asm (".cfi_startproc\n\t.cfi_endproc");

int main () { return 0; }

Teach MC / dwarf emission to handle these cfi directives which essentially
create an empty frame.

rdar://10017184

llvm-svn: 138504

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 5295d0f58f3..7e3d7a6886e 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -190,14 +190,14 @@ void MCStreamer::EmitCFIStartProc() {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   if (CurFrame && !CurFrame->End)
     report_fatal_error("Starting a frame before finishing the previous one!");
-  MCDwarfFrameInfo Frame;
 
+  MCDwarfFrameInfo Frame;
   Frame.Function = LastSymbol;
 
   // If the function is externally visible, we need to create a local
   // symbol to avoid relocations.
   StringRef Prefix = getContext().getAsmInfo().getPrivateGlobalPrefix();
-  if (LastSymbol->getName().startswith(Prefix)) {
+  if (LastSymbol && LastSymbol->getName().startswith(Prefix)) {
     Frame.Begin = LastSymbol;
   } else {
     Frame.Begin = getContext().CreateTempSymbol();