[WinEH] Generate .xdata for catch handlers

This lets us catch exceptions in simple cases.

N.B. Things that do not work include (but are not limited to):
- Throwing from within a catch handler.
- Catching an object with a named catch parameter.
- 'CatchHigh' is fictitious, we aren't sure of its purpose.
- We aren't entirely efficient with regards to the number of EH states
  that we generate.
- IP-to-State tables are sensitive to the order of emission.

llvm-svn: 233767

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 2cb81d06b05..6e7a3bc4db7 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -139,6 +139,11 @@ MCSymbol *MCContext::getOrCreateFrameAllocSymbol(StringRef FuncName,
                            "$frame_escape_" + Twine(Idx));
 }
 
+MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(StringRef FuncName) {
+  return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
+                           "$parent_frame_offset");
+}
+
 MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
   // Determine whether this is an assembler temporary or normal label, if used.
   bool IsTemporary = false;