C++ CallInst::getNextNode方法代码示例

/// Replaces the given call site (Call or Invoke) with a gc.statepoint
/// intrinsic with an empty deoptimization arguments list.  This does
/// NOT do explicit relocation for GC support.
static Value *ReplaceWithStatepoint(const CallSite &CS /* to replace */) {
  assert(CS.getInstruction()->getModule() && "must be set");

  // TODO: technically, a pass is not allowed to get functions from within a
  // function pass since it might trigger a new function addition.  Refactor
  // this logic out to the initialization of the pass.  Doesn't appear to
  // matter in practice.

  // Then go ahead and use the builder do actually do the inserts.  We insert
  // immediately before the previous instruction under the assumption that all
  // arguments will be available here.  We can't insert afterwards since we may
  // be replacing a terminator.
  IRBuilder<> Builder(CS.getInstruction());

  // Note: The gc args are not filled in at this time, that's handled by
  // RewriteStatepointsForGC (which is currently under review).

  // Create the statepoint given all the arguments
  Instruction *Token = nullptr;

  uint64_t ID;
  uint32_t NumPatchBytes;

  AttributeSet OriginalAttrs = CS.getAttributes();
  Attribute AttrID =
      OriginalAttrs.getAttribute(AttributeSet::FunctionIndex, "statepoint-id");
  Attribute AttrNumPatchBytes = OriginalAttrs.getAttribute(
      AttributeSet::FunctionIndex, "statepoint-num-patch-bytes");

  AttrBuilder AttrsToRemove;
  bool HasID = AttrID.isStringAttribute() &&
               !AttrID.getValueAsString().getAsInteger(10, ID);

  if (HasID)
    AttrsToRemove.addAttribute("statepoint-id");
  else
    ID = 0xABCDEF00;

  bool HasNumPatchBytes =
      AttrNumPatchBytes.isStringAttribute() &&
      !AttrNumPatchBytes.getValueAsString().getAsInteger(10, NumPatchBytes);

  if (HasNumPatchBytes)
    AttrsToRemove.addAttribute("statepoint-num-patch-bytes");
  else
    NumPatchBytes = 0;

  OriginalAttrs = OriginalAttrs.removeAttributes(
      CS.getInstruction()->getContext(), AttributeSet::FunctionIndex,
      AttrsToRemove);

  if (CS.isCall()) {
    CallInst *ToReplace = cast<CallInst>(CS.getInstruction());
    CallInst *Call = Builder.CreateGCStatepointCall(
        ID, NumPatchBytes, CS.getCalledValue(),
        makeArrayRef(CS.arg_begin(), CS.arg_end()), None, None,
        "safepoint_token");
    Call->setTailCall(ToReplace->isTailCall());
    Call->setCallingConv(ToReplace->getCallingConv());

    // In case if we can handle this set of attributes - set up function
    // attributes directly on statepoint and return attributes later for
    // gc_result intrinsic.
    Call->setAttributes(OriginalAttrs.getFnAttributes());

    Token = Call;

    // Put the following gc_result and gc_relocate calls immediately after
    // the old call (which we're about to delete).
    assert(ToReplace->getNextNode() && "not a terminator, must have next");
    Builder.SetInsertPoint(ToReplace->getNextNode());
    Builder.SetCurrentDebugLocation(ToReplace->getNextNode()->getDebugLoc());
  } else if (CS.isInvoke()) {
    InvokeInst *ToReplace = cast<InvokeInst>(CS.getInstruction());

    // Insert the new invoke into the old block.  We'll remove the old one in a
    // moment at which point this will become the new terminator for the
    // original block.
    Builder.SetInsertPoint(ToReplace->getParent());
    InvokeInst *Invoke = Builder.CreateGCStatepointInvoke(
        ID, NumPatchBytes, CS.getCalledValue(), ToReplace->getNormalDest(),
        ToReplace->getUnwindDest(), makeArrayRef(CS.arg_begin(), CS.arg_end()),
        None, None, "safepoint_token");

    Invoke->setCallingConv(ToReplace->getCallingConv());

    // In case if we can handle this set of attributes - set up function
    // attributes directly on statepoint and return attributes later for
    // gc_result intrinsic.
    Invoke->setAttributes(OriginalAttrs.getFnAttributes());

    Token = Invoke;

    // We'll insert the gc.result into the normal block
    BasicBlock *NormalDest = ToReplace->getNormalDest();
    // Can not insert gc.result in case of phi nodes preset.
    // Should have removed this cases prior to running this function
//.........这里部分代码省略.........

CallInst* ArgumentRecovery::createCallSite(TargetInfo& targetInfo, const CallInformation& ci, Value& callee, Value& callerRegisters, Instruction& insertionPoint)
{
	LLVMContext& ctx = insertionPoint.getContext();
	
	unsigned pointerSize = targetInfo.getPointerSize() * CHAR_BIT;
	Type* integer = Type::getIntNTy(ctx, pointerSize);
	Type* integerPtr = Type::getIntNPtrTy(ctx, pointerSize, 1);
	
	// Create GEPs in caller for each value that we need.
	// Load SP first since we might need it.
	auto spPtr = targetInfo.getRegister(&callerRegisters, *targetInfo.getStackPointer());
	spPtr->insertBefore(&insertionPoint);
	auto spValue = new LoadInst(spPtr, "sp", &insertionPoint);
	
	// Fix parameters
	SmallVector<Value*, 8> arguments;
	for (const auto& vi : ci.parameters())
	{
		if (vi.type == ValueInformation::IntegerRegister)
		{
			auto registerPtr = targetInfo.getRegister(&callerRegisters, *vi.registerInfo);
			registerPtr->insertBefore(&insertionPoint);
			auto registerValue = new LoadInst(registerPtr, vi.registerInfo->name, &insertionPoint);
			arguments.push_back(registerValue);
		}
		else if (vi.type == ValueInformation::Stack)
		{
			// assume one pointer-sized word
			auto offsetConstant = ConstantInt::get(integer, vi.frameBaseOffset);
			auto offset = BinaryOperator::Create(BinaryOperator::Add, spValue, offsetConstant, "", &insertionPoint);
			auto casted = new IntToPtrInst(offset, integerPtr, "", &insertionPoint);
			auto loaded = new LoadInst(casted, "", &insertionPoint);
			arguments.push_back(loaded);
		}
		else
		{
			llvm_unreachable("not implemented");
		}
	}
	
	CallInst* newCall = CallInst::Create(&callee, arguments, "", &insertionPoint);
	
	// Fix return value(s)
	unsigned i = 0;
	Instruction* returnInsertionPoint = newCall->getNextNode();
	for (const auto& vi : ci.returns())
	{
		if (vi.type == ValueInformation::IntegerRegister)
		{
			Value* registerValue = ci.returns_size() == 1
				? static_cast<Value*>(newCall)
				: ExtractValueInst::Create(newCall, {i}, vi.registerInfo->name, returnInsertionPoint);
			
			auto registerPtr = targetInfo.getRegister(&callerRegisters, *vi.registerInfo);
			registerPtr->insertBefore(returnInsertionPoint);
			new StoreInst(registerValue, registerPtr, returnInsertionPoint);
		}
		else
		{
			llvm_unreachable("not implemented");
		}
		i++;
	}
	
	return newCall;
}

/// \brief Recursively handle the condition leading to a loop
Value *SIAnnotateControlFlow::handleLoopCondition(
    Value *Cond, PHINode *Broken, llvm::Loop *L, BranchInst *Term,
    SmallVectorImpl<WeakTrackingVH> &LoopPhiConditions) {
  // Only search through PHI nodes which are inside the loop.  If we try this
  // with PHI nodes that are outside of the loop, we end up inserting new PHI
  // nodes outside of the loop which depend on values defined inside the loop.
  // This will break the module with
  // 'Instruction does not dominate all users!' errors.
  PHINode *Phi = nullptr;
  if ((Phi = dyn_cast<PHINode>(Cond)) && L->contains(Phi)) {
    BasicBlock *Parent = Phi->getParent();
    PHINode *NewPhi = PHINode::Create(Int64, 0, "loop.phi", &Parent->front());
    Value *Ret = NewPhi;

    // Handle all non-constant incoming values first
    for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
      Value *Incoming = Phi->getIncomingValue(i);
      BasicBlock *From = Phi->getIncomingBlock(i);
      if (isa<ConstantInt>(Incoming)) {
        NewPhi->addIncoming(Broken, From);
        continue;
      }

      Phi->setIncomingValue(i, BoolFalse);
      Value *PhiArg = handleLoopCondition(Incoming, Broken, L,
                                          Term, LoopPhiConditions);
      NewPhi->addIncoming(PhiArg, From);
    }

    BasicBlock *IDom = DT->getNode(Parent)->getIDom()->getBlock();

    for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
      Value *Incoming = Phi->getIncomingValue(i);
      if (Incoming != BoolTrue)
        continue;

      BasicBlock *From = Phi->getIncomingBlock(i);
      if (From == IDom) {
        // We're in the following situation:
        //   IDom/From
        //      |   \
        //      |   If-block
        //      |   /
        //     Parent
        // where we want to break out of the loop if the If-block is not taken.
        // Due to the depth-first traversal, there should be an end.cf
        // intrinsic in Parent, and we insert an else.break before it.
        //
        // Note that the end.cf need not be the first non-phi instruction
        // of parent, particularly when we're dealing with a multi-level
        // break, but it should occur within a group of intrinsic calls
        // at the beginning of the block.
        CallInst *OldEnd = dyn_cast<CallInst>(Parent->getFirstInsertionPt());
        while (OldEnd && OldEnd->getCalledFunction() != EndCf)
          OldEnd = dyn_cast<CallInst>(OldEnd->getNextNode());
        if (OldEnd && OldEnd->getCalledFunction() == EndCf) {
          Value *Args[] = { OldEnd->getArgOperand(0), NewPhi };
          Ret = CallInst::Create(ElseBreak, Args, "", OldEnd);
          continue;
        }
      }

      TerminatorInst *Insert = From->getTerminator();
      Value *PhiArg = CallInst::Create(Break, Broken, "", Insert);
      NewPhi->setIncomingValue(i, PhiArg);
    }

    LoopPhiConditions.push_back(WeakTrackingVH(Phi));
    return Ret;
  }

  if (Instruction *Inst = dyn_cast<Instruction>(Cond)) {
    BasicBlock *Parent = Inst->getParent();
    Instruction *Insert;
    if (L->contains(Inst)) {
      Insert = Parent->getTerminator();
    } else {
      Insert = L->getHeader()->getFirstNonPHIOrDbgOrLifetime();
    }

    Value *Args[] = { Cond, Broken };
    return CallInst::Create(IfBreak, Args, "", Insert);
  }

  // Insert IfBreak in the loop header TERM for constant COND other than true.
  if (isa<Constant>(Cond)) {
    Instruction *Insert = Cond == BoolTrue ?
      Term : L->getHeader()->getTerminator();

    Value *Args[] = { Cond, Broken };
    return CallInst::Create(IfBreak, Args, "", Insert);
  }

  llvm_unreachable("Unhandled loop condition!");
}

void DuettoNativeRewriter::rewriteConstructorImplementation(Module& M, Function& F)
{
	//Copy the code in a function with the right signature
	Function* newFunc=getReturningConstructor(M, &F);
	if(!newFunc->empty())
		return;

	//Visit each instruction and take note of the ones that needs to be replaced
	Function::const_iterator B=F.begin();
	Function::const_iterator BE=F.end();
	ValueToValueMapTy valueMap;
	CallInst* lowerConstructor = NULL;
	const CallInst* oldLowerConstructor = NULL;
	for(;B!=BE;++B)
	{
		BasicBlock::const_iterator I=B->begin();
		BasicBlock::const_iterator IE=B->end();
		for(;I!=IE;++I)
		{
			if(I->getOpcode()!=Instruction::Call)
				continue;
			const CallInst* callInst=cast<CallInst>(&(*I));
			Function* f=callInst->getCalledFunction();
			if(!f)
				continue;
			const char* startOfType;
			const char* endOfType;
			if(!DuettoNativeRewriter::isBuiltinConstructor(f->getName().data(), startOfType, endOfType))
				continue;
			//Check that the constructor is for 'this'
			if(callInst->getOperand(0)!=F.arg_begin())
				continue;
			//If this is another constructor for the same type, change it to a
			//returning constructor and use it as the 'this' argument
			Function* newFunc = getReturningConstructor(M, f);
			llvm::SmallVector<Value*, 4> newArgs;
			for(unsigned i=1;i<callInst->getNumArgOperands();i++)
				newArgs.push_back(callInst->getArgOperand(i));
			lowerConstructor = CallInst::Create(newFunc, newArgs);
			oldLowerConstructor = callInst;
			break;
		}
		if(lowerConstructor)
			break;
	}

	//Clone the linkage first
	newFunc->setLinkage(F.getLinkage());
	Function::arg_iterator origArg=++F.arg_begin();
	Function::arg_iterator newArg=newFunc->arg_begin();
	valueMap.insert(make_pair(F.arg_begin(), lowerConstructor));

	for(unsigned i=1;i<F.arg_size();i++)
	{
		valueMap.insert(make_pair(&(*origArg), &(*newArg)));
		++origArg;
		++newArg;
	}
	SmallVector<ReturnInst*, 4> returns;
	CloneFunctionInto(newFunc, &F, valueMap, false, returns);

	//Find the right place to add the base construtor call
	assert(lowerConstructor->getNumArgOperands()<=1 && "Native constructors with multiple args are not supported");
	Instruction* callPred = NULL;
	if (lowerConstructor->getNumArgOperands()==1 && Instruction::classof(lowerConstructor->getArgOperand(0)))
	{
		//Switch the argument to the one in the new func
		lowerConstructor->setArgOperand(0, valueMap[lowerConstructor->getArgOperand(0)]);
		callPred = cast<Instruction>(lowerConstructor->getArgOperand(0));
	}
	else
		callPred = &newFunc->getEntryBlock().front();

	//Add add it
	lowerConstructor->insertAfter(callPred);

	//Override the returs values
	for(unsigned i=0;i<returns.size();i++)
	{
		Instruction* newInst = ReturnInst::Create(M.getContext(),lowerConstructor);
		newInst->insertBefore(returns[i]);
		returns[i]->removeFromParent();
	}
	//Recursively move all the users of the lower constructor after the call itself
	Instruction* insertPoint = lowerConstructor->getNextNode();
	SmallVector<Value*, 4> usersQueue(lowerConstructor->getNumUses());
	unsigned int i;
	Value::use_iterator it;
	for(i=usersQueue.size()-1,it=lowerConstructor->use_begin();it!=lowerConstructor->use_end();++it,i--)
		usersQueue[i]=it->getUser();

	SmallSet<Instruction*, 4> movedInstructions;
	while(!usersQueue.empty())
	{
		Instruction* cur=dyn_cast<Instruction>(usersQueue.pop_back_val());
		if(!cur)
			continue;
		if(movedInstructions.count(cur))
			continue;
		movedInstructions.insert(cur);
//.........这里部分代码省略.........