[WinEH] Add codegen support for cleanuppad and cleanupret

All of the complexity is in cleanupret, and it mostly follows the same
codepaths as catchret, except it doesn't take a return value in RAX.

This small example now compiles and executes successfully on win32:
  extern "C" int printf(const char *, ...) noexcept;
  struct Dtor {
    ~Dtor() { printf("~Dtor\n"); }
  };
  void has_cleanup() {
    Dtor o;
    throw 42;
  }
  int main() {
    try {
      has_cleanup();
    } catch (int) {
      printf("caught it\n");
    }
  }

Don't try to put the cleanup in the same function as the catch, or Bad
Things will happen.

llvm-svn: 247219

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index e706d73dee2..095315809cb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -316,10 +316,11 @@ void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
 /// Retreive the MCSymbol for a GlobalValue or MachineBasicBlock. GlobalValues
 /// are used in the old WinEH scheme, and they will be removed eventually.
 static MCSymbol *getMCSymbolForMBBOrGV(AsmPrinter *Asm, ValueOrMBB Handler) {
+  if (!Handler)
+    return nullptr;
   if (Handler.is<MachineBasicBlock *>())
     return Handler.get<MachineBasicBlock *>()->getSymbol();
-  else
-    return Asm->getSymbol(cast<GlobalValue>(Handler.get<const Value *>()));
+  return Asm->getSymbol(cast<GlobalValue>(Handler.get<const Value *>()));
 }
 
 void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
@@ -404,8 +405,9 @@ void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
   if (UnwindMapXData) {
     OS.EmitLabel(UnwindMapXData);
     for (const WinEHUnwindMapEntry &UME : FuncInfo.UnwindMap) {
-      OS.EmitIntValue(UME.ToState, 4);                // ToState
-      OS.EmitValue(create32bitRef(UME.Cleanup), 4);   // Action
+      MCSymbol *CleanupSym = getMCSymbolForMBBOrGV(Asm, UME.Cleanup);
+      OS.EmitIntValue(UME.ToState, 4);             // ToState
+      OS.EmitValue(create32bitRef(CleanupSym), 4); // Action
     }
   }