/// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
/// into the caller, update the specified callgraph to reflect the changes we
/// made.  Note that it's possible that not all code was copied over, so only
/// some edges of the callgraph may remain.
static void UpdateCallGraphAfterInlining(CallSite CS,
                                         Function::iterator FirstNewBlock,
                                         ValueToValueMapTy &VMap,
                                         InlineFunctionInfo &IFI) {
  CallGraph &CG = *IFI.CG;
  const Function *Caller = CS.getInstruction()->getParent()->getParent();
  const Function *Callee = CS.getCalledFunction();
  CallGraphNode *CalleeNode = CG[Callee];
  CallGraphNode *CallerNode = CG[Caller];

  // Since we inlined some uninlined call sites in the callee into the caller,
  // add edges from the caller to all of the callees of the callee.
  CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();

  // Consider the case where CalleeNode == CallerNode.
  CallGraphNode::CalledFunctionsVector CallCache;
  if (CalleeNode == CallerNode) {
    CallCache.assign(I, E);
    I = CallCache.begin();
    E = CallCache.end();
  }

  for (; I != E; ++I) {
    const Value *OrigCall = I->first;

    ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
    // Only copy the edge if the call was inlined!
    if (VMI == VMap.end() || VMI->second == 0)
      continue;
    
    // If the call was inlined, but then constant folded, there is no edge to
    // add.  Check for this case.
    Instruction *NewCall = dyn_cast<Instruction>(VMI->second);
    if (NewCall == 0) continue;

    // Remember that this call site got inlined for the client of
    // InlineFunction.
    IFI.InlinedCalls.push_back(NewCall);

    // It's possible that inlining the callsite will cause it to go from an
    // indirect to a direct call by resolving a function pointer.  If this
    // happens, set the callee of the new call site to a more precise
    // destination.  This can also happen if the call graph node of the caller
    // was just unnecessarily imprecise.
    if (I->second->getFunction() == 0)
      if (Function *F = CallSite(NewCall).getCalledFunction()) {
        // Indirect call site resolved to direct call.
        CallerNode->addCalledFunction(CallSite(NewCall), CG[F]);

        continue;
      }

    CallerNode->addCalledFunction(CallSite(NewCall), I->second);
  }
  
  // Update the call graph by deleting the edge from Callee to Caller.  We must
  // do this after the loop above in case Caller and Callee are the same.
  CallerNode->removeCallEdgeFor(CS);
}
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/// DeleteBasicBlock - remove the specified basic block from the program,
/// updating the callgraph to reflect any now-obsolete edges due to calls that
/// exist in the BB.
void PruneEH::DeleteBasicBlock(BasicBlock *BB) {
  assert(pred_empty(BB) && "BB is not dead!");
  CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();

  Instruction *TokenInst = nullptr;

  CallGraphNode *CGN = CG[BB->getParent()];
  for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) {
    --I;

    if (I->getType()->isTokenTy()) {
      TokenInst = &*I;
      break;
    }

    if (auto CS = CallSite (&*I)) {
      const Function *Callee = CS.getCalledFunction();
      if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
        CGN->removeCallEdgeFor(CS);
      else if (!Callee->isIntrinsic())
        CGN->removeCallEdgeFor(CS);
    }

    if (!I->use_empty())
      I->replaceAllUsesWith(UndefValue::get(I->getType()));
  }

  if (TokenInst) {
    if (!isa<TerminatorInst>(TokenInst))
      changeToUnreachable(TokenInst->getNextNode(), /*UseLLVMTrap=*/false);
  } else {
    // Get the list of successors of this block.
    std::vector<BasicBlock *> Succs(succ_begin(BB), succ_end(BB));

    for (unsigned i = 0, e = Succs.size(); i != e; ++i)
      Succs[i]->removePredecessor(BB);

    BB->eraseFromParent();
  }
}
Exemple #3
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/// DeleteBasicBlock - remove the specified basic block from the program,
/// updating the callgraph to reflect any now-obsolete edges due to calls that
/// exist in the BB.
void PruneEH::DeleteBasicBlock(BasicBlock *BB) {
  assert(pred_begin(BB) == pred_end(BB) && "BB is not dead!");
  CallGraph &CG = getAnalysis<CallGraph>();

  CallGraphNode *CGN = CG[BB->getParent()];
  for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) {
    --I;
    if (CallInst *CI = dyn_cast<CallInst>(I)) {
      if (!isa<IntrinsicInst>(I))
        CGN->removeCallEdgeFor(CI);
    } else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
      CGN->removeCallEdgeFor(II);
    if (!I->use_empty())
      I->replaceAllUsesWith(UndefValue::get(I->getType()));
  }

  // Get the list of successors of this block.
  std::vector<BasicBlock*> Succs(succ_begin(BB), succ_end(BB));

  for (unsigned i = 0, e = Succs.size(); i != e; ++i)
    Succs[i]->removePredecessor(BB);

  BB->eraseFromParent();
}
/// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
/// into the caller, update the specified callgraph to reflect the changes we
/// made.  Note that it's possible that not all code was copied over, so only
/// some edges of the callgraph may remain.
static void UpdateCallGraphAfterInlining(CallSite CS,
                                         Function::iterator FirstNewBlock,
                                       DenseMap<const Value*, Value*> &ValueMap,
                                         CallGraph &CG) {
  const Function *Caller = CS.getInstruction()->getParent()->getParent();
  const Function *Callee = CS.getCalledFunction();
  CallGraphNode *CalleeNode = CG[Callee];
  CallGraphNode *CallerNode = CG[Caller];

  // Since we inlined some uninlined call sites in the callee into the caller,
  // add edges from the caller to all of the callees of the callee.
  CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();

  // Consider the case where CalleeNode == CallerNode.
  CallGraphNode::CalledFunctionsVector CallCache;
  if (CalleeNode == CallerNode) {
    CallCache.assign(I, E);
    I = CallCache.begin();
    E = CallCache.end();
  }

  for (; I != E; ++I) {
    const Instruction *OrigCall = I->first.getInstruction();

    DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall);
    // Only copy the edge if the call was inlined!
    if (VMI != ValueMap.end() && VMI->second) {
      // If the call was inlined, but then constant folded, there is no edge to
      // add.  Check for this case.
      if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second))
        CallerNode->addCalledFunction(CallSite::get(NewCall), I->second);
    }
  }
  // Update the call graph by deleting the edge from Callee to Caller.  We must
  // do this after the loop above in case Caller and Callee are the same.
  CallerNode->removeCallEdgeFor(CS);
}
/// updateCallSites - Update all sites that call F to use NF.
CallGraphNode *SRETPromotion::updateCallSites(Function *F, Function *NF) {
  CallGraph &CG = getAnalysis<CallGraph>();
  SmallVector<Value*, 16> Args;

  // Attributes - Keep track of the parameter attributes for the arguments.
  SmallVector<AttributeWithIndex, 8> ArgAttrsVec;

  // Get a new callgraph node for NF.
  CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF);

  while (!F->use_empty()) {
    CallSite CS(*F->use_begin());
    Instruction *Call = CS.getInstruction();

    const AttrListPtr &PAL = F->getAttributes();
    // Add any return attributes.
    if (Attributes attrs = PAL.getRetAttributes())
      ArgAttrsVec.push_back(AttributeWithIndex::get(0, attrs));

    // Copy arguments, however skip first one.
    CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
    Value *FirstCArg = *AI;
    ++AI;
    // 0th parameter attribute is reserved for return type.
    // 1th parameter attribute is for first 1st sret argument.
    unsigned ParamIndex = 2; 
    while (AI != AE) {
      Args.push_back(*AI); 
      if (Attributes Attrs = PAL.getParamAttributes(ParamIndex))
        ArgAttrsVec.push_back(AttributeWithIndex::get(ParamIndex - 1, Attrs));
      ++ParamIndex;
      ++AI;
    }

    // Add any function attributes.
    if (Attributes attrs = PAL.getFnAttributes())
      ArgAttrsVec.push_back(AttributeWithIndex::get(~0, attrs));
    
    AttrListPtr NewPAL = AttrListPtr::get(ArgAttrsVec.begin(), ArgAttrsVec.end());
    
    // Build new call instruction.
    Instruction *New;
    if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
      New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
                               Args.begin(), Args.end(), "", Call);
      cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
      cast<InvokeInst>(New)->setAttributes(NewPAL);
    } else {
      New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call);
      cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
      cast<CallInst>(New)->setAttributes(NewPAL);
      if (cast<CallInst>(Call)->isTailCall())
        cast<CallInst>(New)->setTailCall();
    }
    Args.clear();
    ArgAttrsVec.clear();
    New->takeName(Call);

    // Update the callgraph to know that the callsite has been transformed.
    CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()];
    CalleeNode->removeCallEdgeFor(Call);
    CalleeNode->addCalledFunction(New, NF_CGN);
    
    // Update all users of sret parameter to extract value using extractvalue.
    for (Value::use_iterator UI = FirstCArg->use_begin(), 
           UE = FirstCArg->use_end(); UI != UE; ) {
      User *U2 = *UI++;
      CallInst *C2 = dyn_cast<CallInst>(U2);
      if (C2 && (C2 == Call))
        continue;
      
      GetElementPtrInst *UGEP = cast<GetElementPtrInst>(U2);
      ConstantInt *Idx = cast<ConstantInt>(UGEP->getOperand(2));
      Value *GR = ExtractValueInst::Create(New, Idx->getZExtValue(),
                                           "evi", UGEP);
      while(!UGEP->use_empty()) {
        // isSafeToUpdateAllCallers has checked that all GEP uses are
        // LoadInsts
        LoadInst *L = cast<LoadInst>(*UGEP->use_begin());
        L->replaceAllUsesWith(GR);
        L->eraseFromParent();
      }
      UGEP->eraseFromParent();
      continue;
    }
    Call->eraseFromParent();
  }
  
  return NF_CGN;
}