More exception handling improvements... WIP.
Highlights include:
Add a helper to generate __cxa_free_exception and _ZSt9terminatev.
Add a region to handle EH object deallocation for ctor failures for throw.
Add a terminate handler for __cxa_end_catch.
A framework for adding cleanup actions for the exceptional edges only.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 420e275..85d02bb 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -31,9 +31,21 @@
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
}
+static llvm::Constant *getFreeExceptionFn(CodeGenFunction &CGF) {
+ // void __cxa_free_exception(void *thrown_exception);
+ const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
+ std::vector<const llvm::Type*> Args(1, Int8PtrTy);
+
+ const llvm::FunctionType *FTy =
+ llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
+ Args, false);
+
+ return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
+}
+
static llvm::Constant *getThrowFn(CodeGenFunction &CGF) {
- // void __cxa_throw (void *thrown_exception, std::type_info *tinfo,
- // void (*dest) (void *) );
+ // void __cxa_throw(void *thrown_exception, std::type_info *tinfo,
+ // void (*dest) (void *));
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
std::vector<const llvm::Type*> Args(3, Int8PtrTy);
@@ -46,7 +58,7 @@
}
static llvm::Constant *getReThrowFn(CodeGenFunction &CGF) {
- // void __cxa_rethrow ();
+ // void __cxa_rethrow();
const llvm::FunctionType *FTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
@@ -55,7 +67,7 @@
}
static llvm::Constant *getBeginCatchFn(CodeGenFunction &CGF) {
- // void* __cxa_begin_catch ();
+ // void* __cxa_begin_catch();
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
std::vector<const llvm::Type*> Args(1, Int8PtrTy);
@@ -67,7 +79,7 @@
}
static llvm::Constant *getEndCatchFn(CodeGenFunction &CGF) {
- // void __cxa_end_catch ();
+ // void __cxa_end_catch();
const llvm::FunctionType *FTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
@@ -92,6 +104,15 @@
return CGF.CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume_or_Rethrow");
}
+static llvm::Constant *getTerminateFn(CodeGenFunction &CGF) {
+ // void __terminate();
+
+ const llvm::FunctionType *FTy =
+ llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
+
+ return CGF.CGM.CreateRuntimeFunction(FTy, "_ZSt9terminatev");
+}
+
// CopyObject - Utility to copy an object. Calls copy constructor as necessary.
// N is casted to the right type.
static void CopyObject(CodeGenFunction &CGF, const Expr *E, llvm::Value *N) {
@@ -112,7 +133,19 @@
CGF.EmitAggExpr(E, This, false);
} else if (CXXConstructorDecl *CopyCtor
= RD->getCopyConstructor(CGF.getContext(), 0)) {
- // FIXME: region management
+ // All temporaries end before we call __cxa_throw
+ CodeGenFunction::CleanupScope TryScope(CGF);
+ {
+ // These actions are only on the exceptional edge.
+ CodeGenFunction::DelayedCleanupBlock Scope(CGF, true);
+
+ llvm::Constant *FreeExceptionFn = getFreeExceptionFn(CGF);
+ const llvm::Type *Int8PtrTy
+ = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
+ llvm::Value *ExceptionPtr = CGF.Builder.CreateBitCast(N, Int8PtrTy);
+ CGF.Builder.CreateCall(FreeExceptionFn, ExceptionPtr);
+ }
+
llvm::Value *Src = CGF.EmitLValue(E).getAddress();
// Stolen from EmitClassAggrMemberwiseCopy
@@ -129,9 +162,8 @@
CopyCtor->getType()->getAs<FunctionType>()->getResultType();
CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(ResultType, CallArgs),
Callee, CallArgs, CopyCtor);
- // FIXME: region management
} else
- CGF.ErrorUnsupported(E, "uncopyable object");
+ llvm::llvm_unreachable("uncopyable object");
}
}
@@ -154,7 +186,7 @@
CGF.EmitAggregateCopy(This, E, ObjectType);
} else if (CXXConstructorDecl *CopyCtor
= RD->getCopyConstructor(CGF.getContext(), 0)) {
- // FIXME: region management
+ // FIXME: region management, call terminate
llvm::Value *Src = E;
// Stolen from EmitClassAggrMemberwiseCopy
@@ -241,16 +273,12 @@
llvm::BasicBlock *PrevLandingPad = getInvokeDest();
llvm::BasicBlock *TryHandler = createBasicBlock("try.handler");
-#if 0
llvm::BasicBlock *FinallyBlock = createBasicBlock("finally");
-#endif
llvm::BasicBlock *FinallyRethrow = createBasicBlock("finally.throw");
llvm::BasicBlock *FinallyEnd = createBasicBlock("finally.end");
-#if 0
// Push an EH context entry, used for handling rethrows.
PushCleanupBlock(FinallyBlock);
-#endif
// Emit the statements in the try {} block
setInvokeDest(TryHandler);
@@ -306,6 +334,7 @@
llvm::Value *Selector
= Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(),
SelectorArgs.end(), "selector");
+ llvm::BasicBlock *TerminateHandler = 0;
for (unsigned i = 0; i<S.getNumHandlers(); ++i) {
const CXXCatchStmt *C = S.getHandler(i);
VarDecl *CatchParam = C->getExceptionDecl();
@@ -375,13 +404,15 @@
EmitBlock(MatchEnd);
- // Unfortunately, we also have to generate another EH frame here
- // in case this throws.
- llvm::BasicBlock *MatchEndHandler =
- createBasicBlock("match.end.handler");
- llvm::BasicBlock *Cont = createBasicBlock("myinvoke.cont");
+ // Set up terminate handler
+ bool GenerateTerminate = false;
+ if (!TerminateHandler) {
+ TerminateHandler = createBasicBlock("terminate.handler");
+ GenerateTerminate = true;
+ }
+ llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
Builder.CreateInvoke(getEndCatchFn(*this),
- Cont, MatchEndHandler,
+ Cont, TerminateHandler,
Args.begin(), Args.begin());
EmitBlock(Cont);
@@ -390,19 +421,31 @@
if (Info.EndBlock)
EmitBlock(Info.EndBlock);
- EmitBlock(MatchEndHandler);
Exc = Builder.CreateCall(llvm_eh_exception, "exc");
- // We are required to emit this call to satisfy LLVM, even
- // though we don't use the result.
- Args.clear();
- Args.push_back(Exc);
- Args.push_back(Personality);
- Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
- 0));
- Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
Builder.CreateStore(Exc, RethrowPtr);
EmitBranchThroughCleanup(FinallyRethrow);
+ if (GenerateTerminate) {
+ GenerateTerminate = false;
+ EmitBlock(TerminateHandler);
+ Exc = Builder.CreateCall(llvm_eh_exception, "exc");
+ // We are required to emit this call to satisfy LLVM, even
+ // though we don't use the result.
+ Args.clear();
+ Args.push_back(Exc);
+ Args.push_back(Personality);
+ Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
+ 0));
+ Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
+ llvm::CallInst *TerminateCall =
+ Builder.CreateCall(getTerminateFn(*this));
+ TerminateCall->setDoesNotReturn();
+ Builder.CreateUnreachable();
+
+ // Clear the insertion point to indicate we are in unreachable code.
+ Builder.ClearInsertionPoint();
+ }
+
if (Next)
EmitBlock(Next);
}
@@ -413,7 +456,6 @@
setInvokeDest(PrevLandingPad);
-#if 0
EmitBlock(FinallyBlock);
if (Info.SwitchBlock)
@@ -423,7 +465,6 @@
// Branch around the rethrow code.
EmitBranch(FinallyEnd);
-#endif
EmitBlock(FinallyRethrow);
Builder.CreateCall(getUnwindResumeOrRethrowFn(*this),