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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138504 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 3 insertions, 3 deletions

diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index 06ce502..b57fd9a 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -895,7 +895,7 @@ MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
   const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
   bool verboseAsm = streamer.isVerboseAsm();
 
-  if (!MOFI->isFunctionEHFrameSymbolPrivate() && IsEH) {
+  if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
     MCSymbol *EHSym =
       context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
     streamer.EmitEHSymAttributes(frame.Function, EHSym);
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 5295d0f..7e3d7a6 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/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();