In the fragile ObjC ABI, save the caught exception to the side if there are
both @catches and a @finally, because the second call to @objc_exception_try_enter
will clobber the exception slot. Fixes rdar://problem/8440970.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@115575 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 766703d..c7e4c5f 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -2973,6 +2973,10 @@
llvm::Value *CallTryExitVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(),
"_call_try_exit");
+ // A slot containing the exception to rethrow. Only needed when we
+ // have both a @catch and a @finally.
+ llvm::Value *PropagatingExnVar = 0;
+
// Push a normal cleanup to leave the try scope.
CGF.EHStack.pushCleanup<PerformFragileFinally>(NormalCleanup, &S,
SyncArgSlot,
@@ -3044,6 +3048,12 @@
llvm::BasicBlock *CatchBlock = 0;
llvm::BasicBlock *CatchHandler = 0;
if (HasFinally) {
+ // Save the currently-propagating exception before
+ // objc_exception_try_enter clears the exception slot.
+ PropagatingExnVar = CGF.CreateTempAlloca(Caught->getType(),
+ "propagating_exception");
+ CGF.Builder.CreateStore(Caught, PropagatingExnVar);
+
// Enter a new exception try block (in case a @catch block
// throws an exception).
CGF.Builder.CreateCall(ObjCTypes.getExceptionTryEnterFn(), ExceptionData)
@@ -3178,6 +3188,15 @@
// the try's write hazard and here.
//Hazards.emitWriteHazard();
+ // Extract the new exception and save it to the
+ // propagating-exception slot.
+ assert(PropagatingExnVar);
+ llvm::CallInst *NewCaught =
+ CGF.Builder.CreateCall(ObjCTypes.getExceptionExtractFn(),
+ ExceptionData, "caught");
+ NewCaught->setDoesNotThrow();
+ CGF.Builder.CreateStore(NewCaught, PropagatingExnVar);
+
// Don't pop the catch handler; the throw already did.
CGF.Builder.CreateStore(CGF.Builder.getFalse(), CallTryExitVar);
CGF.EmitBranchThroughCleanup(FinallyRethrow);
@@ -3198,13 +3217,21 @@
CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
CGF.EmitBlock(FinallyRethrow.getBlock(), true);
if (CGF.HaveInsertPoint()) {
- // Just look in the buffer for the exception to throw.
- llvm::CallInst *Caught =
- CGF.Builder.CreateCall(ObjCTypes.getExceptionExtractFn(),
- ExceptionData);
- Caught->setDoesNotThrow();
+ // If we have a propagating-exception variable, check it.
+ llvm::Value *PropagatingExn;
+ if (PropagatingExnVar) {
+ PropagatingExn = CGF.Builder.CreateLoad(PropagatingExnVar);
- CGF.Builder.CreateCall(ObjCTypes.getExceptionThrowFn(), Caught)
+ // Otherwise, just look in the buffer for the exception to throw.
+ } else {
+ llvm::CallInst *Caught =
+ CGF.Builder.CreateCall(ObjCTypes.getExceptionExtractFn(),
+ ExceptionData);
+ Caught->setDoesNotThrow();
+ PropagatingExn = Caught;
+ }
+
+ CGF.Builder.CreateCall(ObjCTypes.getExceptionThrowFn(), PropagatingExn)
->setDoesNotThrow();
CGF.Builder.CreateUnreachable();
}