- // Create an alloca for the incoming jump buffer ptr and the new jump buffer
- // that needs to be restored on all exits from the function. This is an
- // alloca because the value needs to be added to the global context list.
- unsigned Align = 4; // FIXME: Should be a TLI check?
- AllocaInst *FunctionContext =
- new AllocaInst(FunctionContextTy, 0, Align,
- "fcn_context", F.begin()->begin());
-
- Value *Idxs[2];
- Type *Int32Ty = Type::getInt32Ty(F.getContext());
- Value *Zero = ConstantInt::get(Int32Ty, 0);
- // We need to also keep around a reference to the call_site field
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, "call_site",
- EntryBB->getTerminator());
-
- // The exception selector comes back in context->data[1]
- Idxs[1] = ConstantInt::get(Int32Ty, 2);
- Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, "fc_data",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs,
- "exc_selector_gep",
- EntryBB->getTerminator());
- // The exception value comes back in context->data[0]
- Idxs[1] = Zero;
- Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs,
- "exception_gep",
- EntryBB->getTerminator());
-
- // The result of the eh.selector call will be replaced with a a reference to
- // the selector value returned in the function context. We leave the selector
- // itself so the EH analysis later can use it.
- for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
- CallInst *I = EH_Selectors[i];
- Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
- I->replaceAllUsesWith(SelectorVal);
- }
-
- // eh.exception calls are replaced with references to the proper location in
- // the context. Unlike eh.selector, the eh.exception calls are removed
- // entirely.
- for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
- CallInst *I = EH_Exceptions[i];
- // Possible for there to be duplicates, so check to make sure the
- // instruction hasn't already been removed.
- if (!I->getParent()) continue;
- Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
- Type *Ty = Type::getInt8PtrTy(F.getContext());
- Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
-
- I->replaceAllUsesWith(Val);
- I->eraseFromParent();
- }
-
- for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
- ReplaceLandingPadVal(F, LandingPads[i], ExceptionAddr, SelectorAddr);
-
- // The entry block changes to have the eh.sjlj.setjmp, with a conditional
- // branch to a dispatch block for non-zero returns. If we return normally,
- // we're not handling an exception and just register the function context and
- // continue.
-
- // Create the dispatch block. The dispatch block is basically a big switch
- // statement that goes to all of the invoke landing pads.
- BasicBlock *DispatchBlock =
- BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
-
- // Insert a load of the callsite in the dispatch block, and a switch on its
- // value. By default, we issue a trap statement.
- BasicBlock *TrapBlock =
- BasicBlock::Create(F.getContext(), "trapbb", &F);
- CallInst::Create(Intrinsic::getDeclaration(F.getParent(), Intrinsic::trap),
- "", TrapBlock);
- new UnreachableInst(F.getContext(), TrapBlock);
-
- Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
- DispatchBlock);
- SwitchInst *DispatchSwitch =
- SwitchInst::Create(DispatchLoad, TrapBlock, Invokes.size(),
- DispatchBlock);
- // Split the entry block to insert the conditional branch for the setjmp.
- BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
- "eh.sjlj.setjmp.cont");
-
- // Populate the Function Context
- // 1. LSDA address
- // 2. Personality function address
- // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)