void TryCatchFinallyScopes::pushTryCatch(TryCatchStatement *stmt,
llvm::BasicBlock *endbb) {
TryCatchScope scope(irs, getOrCreateEhPtrSlot(), stmt, endbb);
// Only after emitting all the catch bodies, register the catch scopes.
// This is so that (re)throwing inside a catch does not match later
// catches.
tryCatchScopes.push_back(scope);
if (!useMSVCEH())
landingPadsPerCleanupScope[currentCleanupScope()].push_back(nullptr);
}
llvm::BasicBlock *TryCatchFinallyScopes::getOrCreateResumeUnwindBlock() {
if (!resumeUnwindBlock) {
resumeUnwindBlock = irs.insertBB("eh.resume");
llvm::BasicBlock *oldBB = irs.scopebb();
irs.scope() = IRScope(resumeUnwindBlock);
llvm::Function *resumeFn =
getRuntimeFunction(Loc(), irs.module, "_d_eh_resume_unwind");
irs.ir->CreateCall(resumeFn, DtoLoad(getOrCreateEhPtrSlot()));
irs.ir->CreateUnreachable();
irs.scope() = IRScope(oldBB);
}
return resumeUnwindBlock;
}
llvm::BasicBlock *IrFunction::getOrCreateResumeUnwindBlock() {
assert(func == gIR->topfunc() &&
"Should only access unwind resume block while emitting function.");
if (!resumeUnwindBlock) {
resumeUnwindBlock =
llvm::BasicBlock::Create(gIR->context(), "eh.resume", func);
llvm::BasicBlock *oldBB = gIR->scopebb();
gIR->scope() = IRScope(resumeUnwindBlock);
llvm::Function *resumeFn =
getRuntimeFunction(Loc(), gIR->module, "_d_eh_resume_unwind");
gIR->ir->CreateCall(resumeFn, gIR->ir->CreateLoad(getOrCreateEhPtrSlot()));
gIR->ir->CreateUnreachable();
gIR->scope() = IRScope(oldBB);
}
return resumeUnwindBlock;
}
llvm::BasicBlock *TryCatchFinallyScopes::emitLandingPad() {
#if LDC_LLVM_VER >= 308
if (useMSVCEH()) {
assert(currentCleanupScope() > 0);
return emitLandingPadMSVC(currentCleanupScope() - 1);
}
#endif
// save and rewrite scope
IRScope savedIRScope = irs.scope();
// insert landing pads at the end of the function, in emission order,
// to improve human-readability of the IR
llvm::BasicBlock *beginBB = irs.insertBBBefore(nullptr, "landingPad");
irs.scope() = IRScope(beginBB);
llvm::LandingPadInst *landingPad = createLandingPadInst(irs);
// Stash away the exception object pointer and selector value into their
// stack slots.
llvm::Value *ehPtr = DtoExtractValue(landingPad, 0);
irs.ir->CreateStore(ehPtr, getOrCreateEhPtrSlot());
llvm::Value *ehSelector = DtoExtractValue(landingPad, 1);
if (!ehSelectorSlot)
ehSelectorSlot = DtoRawAlloca(ehSelector->getType(), 0, "eh.selector");
irs.ir->CreateStore(ehSelector, ehSelectorSlot);
// Add landingpad clauses, emit finallys and 'if' chain to catch the
// exception.
CleanupCursor lastCleanup = currentCleanupScope();
for (auto it = tryCatchScopes.rbegin(), end = tryCatchScopes.rend();
it != end; ++it) {
const auto &tryCatchScope = *it;
// Insert any cleanups in between the previous (inner-more) try-catch scope
// and this one.
const auto newCleanup = tryCatchScope.getCleanupScope();
assert(lastCleanup >= newCleanup);
if (lastCleanup > newCleanup) {
landingPad->setCleanup(true);
llvm::BasicBlock *afterCleanupBB =
irs.insertBB(beginBB->getName() + llvm::Twine(".after.cleanup"));
runCleanups(lastCleanup, newCleanup, afterCleanupBB);
irs.scope() = IRScope(afterCleanupBB);
lastCleanup = newCleanup;
}
for (const auto &cb : tryCatchScope.getCatchBlocks()) {
// Add the ClassInfo reference to the landingpad instruction so it is
// emitted to the EH tables.
landingPad->addClause(cb.classInfoPtr);
llvm::BasicBlock *mismatchBB =
irs.insertBB(beginBB->getName() + llvm::Twine(".mismatch"));
// "Call" llvm.eh.typeid.for, which gives us the eh selector value to
// compare the landing pad selector value with.
llvm::Value *ehTypeId =
irs.ir->CreateCall(GET_INTRINSIC_DECL(eh_typeid_for),
DtoBitCast(cb.classInfoPtr, getVoidPtrType()));
// Compare the selector value from the unwinder against the expected
// one and branch accordingly.
irs.ir->CreateCondBr(
irs.ir->CreateICmpEQ(irs.ir->CreateLoad(ehSelectorSlot), ehTypeId),
cb.bodyBB, mismatchBB, cb.branchWeights);
irs.scope() = IRScope(mismatchBB);
}
}
// No catch matched. Execute all finallys and resume unwinding.
auto resumeUnwindBlock = getOrCreateResumeUnwindBlock();
if (lastCleanup > 0) {
landingPad->setCleanup(true);
runCleanups(lastCleanup, 0, resumeUnwindBlock);
} else if (!tryCatchScopes.empty()) {
// Directly convert the last mismatch branch into a branch to the
// unwind resume block.
irs.scopebb()->replaceAllUsesWith(resumeUnwindBlock);
irs.scopebb()->eraseFromParent();
} else {
irs.ir->CreateBr(resumeUnwindBlock);
}
irs.scope() = savedIRScope;
return beginBB;
}
