C++ StoreInst::getNextNode方法代码示例

bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) {
  Module &M = *F.getParent();
  LLVMContext &C = F.getContext();
  IRBuilder<> IRB(C);
  SmallVector<Instruction *, 64> ToErase;
  // Vector of %setjmpTable values
  std::vector<Instruction *> SetjmpTableInsts;
  // Vector of %setjmpTableSize values
  std::vector<Instruction *> SetjmpTableSizeInsts;

  // Setjmp preparation

  // This instruction effectively means %setjmpTableSize = 4.
  // We create this as an instruction intentionally, and we don't want to fold
  // this instruction to a constant 4, because this value will be used in
  // SSAUpdater.AddAvailableValue(...) later.
  BasicBlock &EntryBB = F.getEntryBlock();
  BinaryOperator *SetjmpTableSize = BinaryOperator::Create(
      Instruction::Add, IRB.getInt32(4), IRB.getInt32(0), "setjmpTableSize",
      &*EntryBB.getFirstInsertionPt());
  // setjmpTable = (int *) malloc(40);
  Instruction *SetjmpTable = CallInst::CreateMalloc(
      SetjmpTableSize, IRB.getInt32Ty(), IRB.getInt32Ty(), IRB.getInt32(40),
      nullptr, nullptr, "setjmpTable");
  // setjmpTable[0] = 0;
  IRB.SetInsertPoint(SetjmpTableSize);
  IRB.CreateStore(IRB.getInt32(0), SetjmpTable);
  SetjmpTableInsts.push_back(SetjmpTable);
  SetjmpTableSizeInsts.push_back(SetjmpTableSize);

  // Setjmp transformation
  std::vector<PHINode *> SetjmpRetPHIs;
  Function *SetjmpF = M.getFunction("setjmp");
  for (User *U : SetjmpF->users()) {
    auto *CI = dyn_cast<CallInst>(U);
    if (!CI)
      report_fatal_error("Does not support indirect calls to setjmp");

    BasicBlock *BB = CI->getParent();
    if (BB->getParent() != &F) // in other function
      continue;

    // The tail is everything right after the call, and will be reached once
    // when setjmp is called, and later when longjmp returns to the setjmp
    BasicBlock *Tail = SplitBlock(BB, CI->getNextNode());
    // Add a phi to the tail, which will be the output of setjmp, which
    // indicates if this is the first call or a longjmp back. The phi directly
    // uses the right value based on where we arrive from
    IRB.SetInsertPoint(Tail->getFirstNonPHI());
    PHINode *SetjmpRet = IRB.CreatePHI(IRB.getInt32Ty(), 2, "setjmp.ret");

    // setjmp initial call returns 0
    SetjmpRet->addIncoming(IRB.getInt32(0), BB);
    // The proper output is now this, not the setjmp call itself
    CI->replaceAllUsesWith(SetjmpRet);
    // longjmp returns to the setjmp will add themselves to this phi
    SetjmpRetPHIs.push_back(SetjmpRet);

    // Fix call target
    // Our index in the function is our place in the array + 1 to avoid index
    // 0, because index 0 means the longjmp is not ours to handle.
    IRB.SetInsertPoint(CI);
    Value *Args[] = {CI->getArgOperand(0), IRB.getInt32(SetjmpRetPHIs.size()),
                     SetjmpTable, SetjmpTableSize};
    Instruction *NewSetjmpTable =
        IRB.CreateCall(SaveSetjmpF, Args, "setjmpTable");
    Instruction *NewSetjmpTableSize =
        IRB.CreateLoad(TempRet0GV, "setjmpTableSize");
    SetjmpTableInsts.push_back(NewSetjmpTable);
    SetjmpTableSizeInsts.push_back(NewSetjmpTableSize);
    ToErase.push_back(CI);
  }

  // Update each call that can longjmp so it can return to a setjmp where
  // relevant.

  // Because we are creating new BBs while processing and don't want to make
  // all these newly created BBs candidates again for longjmp processing, we
  // first make the vector of candidate BBs.
  std::vector<BasicBlock *> BBs;
  for (BasicBlock &BB : F)
    BBs.push_back(&BB);

  // BBs.size() will change within the loop, so we query it every time
  for (unsigned i = 0; i < BBs.size(); i++) {
    BasicBlock *BB = BBs[i];
    for (Instruction &I : *BB) {
      assert(!isa<InvokeInst>(&I));
      auto *CI = dyn_cast<CallInst>(&I);
      if (!CI)
        continue;

      const Value *Callee = CI->getCalledValue();
      if (!canLongjmp(M, Callee))
        continue;

      Value *Threw = nullptr;
      BasicBlock *Tail;
      if (Callee->getName().startswith(InvokePrefix)) {
        // If invoke wrapper has already been generated for this call in
//.........这里部分代码省略.........