+FunctionPass *llvm::createDwarfEHPass(const TargetMachine *TM) {
+ return new DwarfEHPrepare(TM);
+}
+
+/// GetExceptionObject - Return the exception object from the value passed into
+/// the 'resume' instruction (typically an aggregate). Clean up any dead
+/// instructions, including the 'resume' instruction.
+Value *DwarfEHPrepare::GetExceptionObject(ResumeInst *RI) {
+ Value *V = RI->getOperand(0);
+ Value *ExnObj = nullptr;
+ InsertValueInst *SelIVI = dyn_cast<InsertValueInst>(V);
+ LoadInst *SelLoad = nullptr;
+ InsertValueInst *ExcIVI = nullptr;
+ bool EraseIVIs = false;
+
+ if (SelIVI) {
+ if (SelIVI->getNumIndices() == 1 && *SelIVI->idx_begin() == 1) {
+ ExcIVI = dyn_cast<InsertValueInst>(SelIVI->getOperand(0));
+ if (ExcIVI && isa<UndefValue>(ExcIVI->getOperand(0)) &&
+ ExcIVI->getNumIndices() == 1 && *ExcIVI->idx_begin() == 0) {
+ ExnObj = ExcIVI->getOperand(1);
+ SelLoad = dyn_cast<LoadInst>(SelIVI->getOperand(1));
+ EraseIVIs = true;
+ }
+ }
+ }
+
+ if (!ExnObj)
+ ExnObj = ExtractValueInst::Create(RI->getOperand(0), 0, "exn.obj", RI);
+
+ RI->eraseFromParent();
+
+ if (EraseIVIs) {
+ if (SelIVI->getNumUses() == 0)
+ SelIVI->eraseFromParent();
+ if (ExcIVI->getNumUses() == 0)
+ ExcIVI->eraseFromParent();
+ if (SelLoad && SelLoad->getNumUses() == 0)
+ SelLoad->eraseFromParent();
+ }
+
+ return ExnObj;