C++ IntrinsicInst类代码示例

/// Escape RegNode so that we can access it from child handlers. Find the call
/// to localescape, if any, in the entry block and append RegNode to the list
/// of arguments.
int WinEHStatePass::escapeRegNode(Function &F) {
    // Find the call to localescape and extract its arguments.
    IntrinsicInst *EscapeCall = nullptr;
    for (Instruction &I : F.getEntryBlock()) {
        IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
        if (II && II->getIntrinsicID() == Intrinsic::localescape) {
            EscapeCall = II;
            break;
        }
    }
    SmallVector<Value *, 8> Args;
    if (EscapeCall) {
        auto Ops = EscapeCall->arg_operands();
        Args.append(Ops.begin(), Ops.end());
    }
    Args.push_back(RegNode);

    // Replace the call (if it exists) with new one. Otherwise, insert at the end
    // of the entry block.
    IRBuilder<> Builder(&F.getEntryBlock(),
                        EscapeCall ? EscapeCall : F.getEntryBlock().end());
    Builder.CreateCall(FrameEscape, Args);
    if (EscapeCall)
        EscapeCall->eraseFromParent();
    return Args.size() - 1;
}

static bool allPredCameFromBeginCatch(
    BasicBlock *BB, BasicBlock::reverse_iterator InstRbegin,
    IntrinsicInst **SecondEndCatch, SmallSet<BasicBlock *, 4> &VisitedBlocks) {
  VisitedBlocks.insert(BB);
  // Look for a begincatch in this block.
  for (BasicBlock::reverse_iterator RI = InstRbegin, RE = BB->rend(); RI != RE;
       ++RI) {
    IntrinsicInst *IC = dyn_cast<IntrinsicInst>(&*RI);
    if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch)
      return true;
    // If we find another end catch before we find a begin catch, that's
    // an error.
    if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch) {
      *SecondEndCatch = IC;
      return false;
    }
    // If we encounter a landingpad instruction, the search failed.
    if (isa<LandingPadInst>(*RI))
      return false;
  }
  // If while searching we find a block with no predeccesors,
  // the search failed.
  if (pred_empty(BB))
    return false;
  // Search any predecessors we haven't seen before.
  for (BasicBlock *Pred : predecessors(BB)) {
    if (VisitedBlocks.count(Pred))
      continue;
    if (!allPredCameFromBeginCatch(Pred, Pred->rbegin(), SecondEndCatch,
                                   VisitedBlocks))
      return false;
  }
  return true;
}

static bool
allSuccessorsReachEndCatch(BasicBlock *BB, BasicBlock::iterator InstBegin,
                           IntrinsicInst **SecondBeginCatch,
                           SmallSet<BasicBlock *, 4> &VisitedBlocks) {
  VisitedBlocks.insert(BB);
  for (BasicBlock::iterator I = InstBegin, E = BB->end(); I != E; ++I) {
    IntrinsicInst *IC = dyn_cast<IntrinsicInst>(I);
    if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch)
      return true;
    // If we find another begincatch while looking for an endcatch,
    // that's also an error.
    if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch) {
      *SecondBeginCatch = IC;
      return false;
    }
  }

  // If we reach a block with no successors while searching, the
  // search has failed.
  if (succ_empty(BB))
    return false;
  // Otherwise, search all of the successors.
  for (BasicBlock *Succ : successors(BB)) {
    if (VisitedBlocks.count(Succ))
      continue;
    if (!allSuccessorsReachEndCatch(Succ, Succ->begin(), SecondBeginCatch,
                                    VisitedBlocks))
      return false;
  }
  return true;
}

bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
    BasicBlock *BB = CI->getParent();

    // Lower inline assembly if we can.
    // If we found an inline asm expession, and if the target knows how to
    // lower it to normal LLVM code, do so now.
    if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
        if (TLI->ExpandInlineAsm(CI)) {
            // Avoid invalidating the iterator.
            CurInstIterator = BB->begin();
            // Avoid processing instructions out of order, which could cause
            // reuse before a value is defined.
            SunkAddrs.clear();
            return true;
        }
        // Sink address computing for memory operands into the block.
        if (OptimizeInlineAsmInst(CI))
            return true;
    }

    // Lower all uses of llvm.objectsize.*
    IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
    if (II && II->getIntrinsicID() == Intrinsic::objectsize) {
        bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
        Type *ReturnTy = CI->getType();
        Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);

        // Substituting this can cause recursive simplifications, which can
        // invalidate our iterator.  Use a WeakVH to hold onto it in case this
        // happens.
        WeakVH IterHandle(CurInstIterator);

        ReplaceAndSimplifyAllUses(CI, RetVal, TLI ? TLI->getTargetData() : 0,
                                  TLInfo, ModifiedDT ? 0 : DT);

        // If the iterator instruction was recursively deleted, start over at the
        // start of the block.
        if (IterHandle != CurInstIterator) {
            CurInstIterator = BB->begin();
            SunkAddrs.clear();
        }
        return true;
    }

    // From here on out we're working with named functions.
    if (CI->getCalledFunction() == 0) return false;

    // We'll need TargetData from here on out.
    const TargetData *TD = TLI ? TLI->getTargetData() : 0;
    if (!TD) return false;

    // Lower all default uses of _chk calls.  This is very similar
    // to what InstCombineCalls does, but here we are only lowering calls
    // that have the default "don't know" as the objectsize.  Anything else
    // should be left alone.
    CodeGenPrepareFortifiedLibCalls Simplifier;
    return Simplifier.fold(CI, TD);
}

void AAAnalyzer::handle_instrinsic(Instruction *inst) {
    IntrinsicInst * call = (IntrinsicInst*) inst;
    switch (call->getIntrinsicID()) {
            // Variable Argument Handling Intrinsics
        case Intrinsic::vastart:
        {
            Value * va_list_ptr = call->getArgOperand(0);
            wrapValue(va_list_ptr);
        }
            break;
        case Intrinsic::vaend:
        {
        }
            break;
        case Intrinsic::vacopy: // the same with memmove/memcpy

            //Standard C Library Intrinsics
        case Intrinsic::memmove:
        case Intrinsic::memcpy:
        {
            Value * src_ptr = call->getArgOperand(0);
            Value * dst_ptr = call->getArgOperand(1);

            DyckVertex* src_ptr_ver = wrapValue(src_ptr);
            DyckVertex* dst_ptr_ver = wrapValue(dst_ptr);

            DyckVertex* src_ver = addPtrTo(src_ptr_ver, NULL);
            DyckVertex* dst_ver = addPtrTo(dst_ptr_ver, NULL);

            makeAlias(src_ver, dst_ver);
        }
            break;
        case Intrinsic::memset:
        {
            Value * ptr = call->getArgOperand(0);
            Value * val = call->getArgOperand(1);
            addPtrTo(wrapValue(ptr), wrapValue(val));
        }
            break;
            /// @todo other C lib intrinsics

            //Accurate Garbage Collection Intrinsics
            //Code Generator Intrinsics
            //Bit Manipulation Intrinsics
            //Exception Handling Intrinsics
            //Trampoline Intrinsics
            //Memory Use Markers
            //General Intrinsics

            //Arithmetic with Overflow Intrinsics
            //Specialised Arithmetic Intrinsics
            //Half Precision Floating Point Intrinsics
            //Debugger Intrinsics
        default:break;
    }
}

bool AMDGPUCodeGenPrepare::promoteUniformBitreverseToI32(
    IntrinsicInst &I) const {
  assert(I.getIntrinsicID() == Intrinsic::bitreverse &&
         "I must be bitreverse intrinsic");
  assert(needsPromotionToI32(I.getType()) &&
         "I does not need promotion to i32");

  IRBuilder<> Builder(&I);
  Builder.SetCurrentDebugLocation(I.getDebugLoc());

  Type *I32Ty = getI32Ty(Builder, I.getType());
  Function *I32 =
      Intrinsic::getDeclaration(Mod, Intrinsic::bitreverse, { I32Ty });
  Value *ExtOp = Builder.CreateZExt(I.getOperand(0), I32Ty);
  Value *ExtRes = Builder.CreateCall(I32, { ExtOp });
  Value *LShrOp =
      Builder.CreateLShr(ExtRes, 32 - getBaseElementBitWidth(I.getType()));
  Value *TruncRes =
      Builder.CreateTrunc(LShrOp, I.getType());

  I.replaceAllUsesWith(TruncRes);
  I.eraseFromParent();

  return true;
}

/// getStoredPointerOperand - Return the pointer that is being written to.
static Value *getStoredPointerOperand(Instruction *I) {
  if (StoreInst *SI = dyn_cast<StoreInst>(I))
    return SI->getPointerOperand();
  if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I))
    return MI->getDest();

  IntrinsicInst *II = cast<IntrinsicInst>(I);
  switch (II->getIntrinsicID()) {
  default: llvm_unreachable("Unexpected intrinsic!");
  case Intrinsic::init_trampoline:
    return II->getArgOperand(0);
  }
}

/// isShortenable - Returns true if this instruction can be safely shortened in
/// length.
static bool isShortenable(Instruction *I) {
  // Don't shorten stores for now
  if (isa<StoreInst>(I))
    return false;
  
  IntrinsicInst *II = cast<IntrinsicInst>(I);
  switch (II->getIntrinsicID()) {
    default: return false;
    case Intrinsic::memset:
    case Intrinsic::memcpy:
      // Do shorten memory intrinsics.
      return true;
  }
}

bool CodeExtractor::isLegalToShrinkwrapLifetimeMarkers(
    Instruction *Addr) const {
  AllocaInst *AI = cast<AllocaInst>(Addr->stripInBoundsConstantOffsets());
  Function *Func = (*Blocks.begin())->getParent();
  for (BasicBlock &BB : *Func) {
    if (Blocks.count(&BB))
      continue;
    for (Instruction &II : BB) {

      if (isa<DbgInfoIntrinsic>(II))
        continue;

      unsigned Opcode = II.getOpcode();
      Value *MemAddr = nullptr;
      switch (Opcode) {
      case Instruction::Store:
      case Instruction::Load: {
        if (Opcode == Instruction::Store) {
          StoreInst *SI = cast<StoreInst>(&II);
          MemAddr = SI->getPointerOperand();
        } else {
          LoadInst *LI = cast<LoadInst>(&II);
          MemAddr = LI->getPointerOperand();
        }
        // Global variable can not be aliased with locals.
        if (dyn_cast<Constant>(MemAddr))
          break;
        Value *Base = MemAddr->stripInBoundsConstantOffsets();
        if (!dyn_cast<AllocaInst>(Base) || Base == AI)
          return false;
        break;
      }
      default: {
        IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(&II);
        if (IntrInst) {
          if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start ||
              IntrInst->getIntrinsicID() == Intrinsic::lifetime_end)
            break;
          return false;
        }
        // Treat all the other cases conservatively if it has side effects.
        if (II.mayHaveSideEffects())
          return false;
      }
      }
    }
  }

  return true;
}

bool AMDGPUCodeGenPrepare::visitIntrinsicInst(IntrinsicInst &I) {
  switch (I.getIntrinsicID()) {
  case Intrinsic::bitreverse:
    return visitBitreverseIntrinsicInst(I);
  default:
    return false;
  }
}

/// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
void DwarfEHPrepare::
FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
                        SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels) {
  for (Value::use_iterator
         I = SelectorIntrinsic->use_begin(),
         E = SelectorIntrinsic->use_end(); I != E; ++I) {
    IntrinsicInst *II = cast<IntrinsicInst>(*I);

    if (II->getParent()->getParent() != F)
      continue;

    if (!HasCatchAllInSelector(II))
      Sels.insert(II);
    else
      CatchAllSels.insert(II);
  }
}

// TODO: Ideally  we should share Inliner's InlineCost Analysis code.
// For now use a simplified version. The returned 'InlineCost' will be used
// to esimate the size cost as well as runtime cost of the BB.
int PartialInlinerImpl::computeBBInlineCost(BasicBlock *BB) {
  int InlineCost = 0;
  const DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
  for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
    if (isa<DbgInfoIntrinsic>(I))
      continue;

    switch (I->getOpcode()) {
    case Instruction::BitCast:
    case Instruction::PtrToInt:
    case Instruction::IntToPtr:
    case Instruction::Alloca:
      continue;
    case Instruction::GetElementPtr:
      if (cast<GetElementPtrInst>(I)->hasAllZeroIndices())
        continue;
    default:
      break;
    }

    IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(I);
    if (IntrInst) {
      if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start ||
          IntrInst->getIntrinsicID() == Intrinsic::lifetime_end)
        continue;
    }

    if (CallInst *CI = dyn_cast<CallInst>(I)) {
      InlineCost += getCallsiteCost(CallSite(CI), DL);
      continue;
    }

    if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
      InlineCost += getCallsiteCost(CallSite(II), DL);
      continue;
    }

    if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
      InlineCost += (SI->getNumCases() + 1) * InlineConstants::InstrCost;
      continue;
    }
    InlineCost += InlineConstants::InstrCost;
  }
  return InlineCost;
}

bool AMDGPUCodeGenPrepare::visitBitreverseIntrinsicInst(IntrinsicInst &I) {
  bool Changed = false;

  if (ST->has16BitInsts() && needsPromotionToI32(I.getType()) &&
      DA->isUniform(&I))
    Changed |= promoteUniformBitreverseToI32(I);

  return Changed;
}

/// \brief Split sadd.with.overflow into add + sadd.with.overflow to allow
/// analysis and optimization.
///
/// \return A new value representing the non-overflowing add if possible,
/// otherwise return the original value.
Instruction *SimplifyIndvar::splitOverflowIntrinsic(Instruction *IVUser,
                                                    const DominatorTree *DT) {
  IntrinsicInst *II = dyn_cast<IntrinsicInst>(IVUser);
  if (!II || II->getIntrinsicID() != Intrinsic::sadd_with_overflow)
    return IVUser;

  // Find a branch guarded by the overflow check.
  BranchInst *Branch = 0;
  Instruction *AddVal = 0;
  for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
       UI != E; ++UI) {
    if (ExtractValueInst *ExtractInst = dyn_cast<ExtractValueInst>(*UI)) {
      if (ExtractInst->getNumIndices() != 1)
        continue;
      if (ExtractInst->getIndices()[0] == 0)
        AddVal = ExtractInst;
      else if (ExtractInst->getIndices()[0] == 1 && ExtractInst->hasOneUse())
        Branch = dyn_cast<BranchInst>(ExtractInst->use_back());
    }
  }
  if (!AddVal || !Branch)
    return IVUser;

  BasicBlock *ContinueBB = Branch->getSuccessor(1);
  if (llvm::next(pred_begin(ContinueBB)) != pred_end(ContinueBB))
    return IVUser;

  // Check if all users of the add are provably NSW.
  bool AllNSW = true;
  for (Value::use_iterator UI = AddVal->use_begin(), E = AddVal->use_end();
       UI != E; ++UI) {
    if (Instruction *UseInst = dyn_cast<Instruction>(*UI)) {
      BasicBlock *UseBB = UseInst->getParent();
      if (PHINode *PHI = dyn_cast<PHINode>(UseInst))
        UseBB = PHI->getIncomingBlock(UI);
      if (!DT->dominates(ContinueBB, UseBB)) {
        AllNSW = false;
        break;
      }
    }
  }
  if (!AllNSW)
    return IVUser;

  // Go for it...
  IRBuilder<> Builder(IVUser);
  Instruction *AddInst = dyn_cast<Instruction>(
    Builder.CreateNSWAdd(II->getOperand(0), II->getOperand(1)));

  // The caller expects the new add to have the same form as the intrinsic. The
  // IV operand position must be the same.
  assert((AddInst->getOpcode() == Instruction::Add &&
          AddInst->getOperand(0) == II->getOperand(0)) &&
         "Bad add instruction created from overflow intrinsic.");

  AddVal->replaceAllUsesWith(AddInst);
  DeadInsts.push_back(AddVal);
  return AddInst;
}

static bool isCallPromotable(CallInst *CI) {
  IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
  if (!II)
    return false;

  switch (II->getIntrinsicID()) {
  case Intrinsic::memcpy:
  case Intrinsic::memmove:
  case Intrinsic::memset:
  case Intrinsic::lifetime_start:
  case Intrinsic::lifetime_end:
  case Intrinsic::invariant_start:
  case Intrinsic::invariant_end:
  case Intrinsic::invariant_group_barrier:
  case Intrinsic::objectsize:
    return true;
  default:
    return false;
  }
}