[WinEH] Emit EH tables for __CxxFrameHandler3 on 32-bit x86

Small (really small!) C++ exception handling examples work on 32-bit x86
now.

This change disables the use of .seh_* directives in WinException when
CFI is not in use. It also uses absolute symbol references in the tables
instead of imagerel32 relocations.

Also fixes a cache invalidation bug in MMI personality classification.

llvm-svn: 238575

2 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index cabe63b029f..be31bc976b1 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -1102,9 +1102,9 @@ void MCAsmStreamer::EmitWinEHHandlerData() {
   // We only do this so the section switch that terminates the handler
   // data block is visible.
   WinEH::FrameInfo *CurFrame = getCurrentWinFrameInfo();
-  if (MCSection *XData = WinEH::UnwindEmitter::getXDataSection(
-          CurFrame->Function, getContext()))
-    SwitchSectionNoChange(XData);
+  MCSection *XData =
+      WinEH::UnwindEmitter::getXDataSection(CurFrame->Function, getContext());
+  SwitchSectionNoChange(XData);
 
   OS << "\t.seh_handlerdata";
   EmitEOL();
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 71d4b06b5d9..03ef7eda72c 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -391,11 +391,17 @@ void MCStreamer::EmitCFIWindowSave() {
 }
 
 void MCStreamer::EnsureValidWinFrameInfo() {
+  const MCAsmInfo *MAI = Context.getAsmInfo();
+  if (!MAI->usesWindowsCFI())
+    report_fatal_error(".seh_* directives are not supported on this target");
   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End)
     report_fatal_error("No open Win64 EH frame function!");
 }
 
 void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol) {
+  const MCAsmInfo *MAI = Context.getAsmInfo();
+  if (!MAI->usesWindowsCFI())
+    report_fatal_error(".seh_* directives are not supported on this target");
   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
     report_fatal_error("Starting a function before ending the previous one!");