/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp

Bug Summary

File:	llvm/lib/Transforms/Utils/CodeExtractor.cpp
Warning:	line 997, column 33 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CodeExtractor.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/build-llvm/lib/Transforms/Utils -resource-dir /usr/lib/llvm-13/lib/clang/13.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/build-llvm/lib/Transforms/Utils -I /build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils -I /build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/build-llvm/include -I /build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-13/lib/clang/13.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/build-llvm/lib/Transforms/Utils -fdebug-prefix-map=/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-03-15-022507-3198-1 -x c++ /build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp
1//===- CodeExtractor.cpp - Pull code region into a new function -----------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the interface to tear out a code region, such as an
10// individual loop or a parallel section, into a new function, replacing it with
11// a call to the new function.
12//
13//===----------------------------------------------------------------------===//

15#include "llvm/Transforms/Utils/CodeExtractor.h"
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/Optional.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SetVector.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/Analysis/AssumptionCache.h"
24#include "llvm/Analysis/BlockFrequencyInfo.h"
25#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
26#include "llvm/Analysis/BranchProbabilityInfo.h"
27#include "llvm/Analysis/LoopInfo.h"
28#include "llvm/IR/Argument.h"
29#include "llvm/IR/Attributes.h"
30#include "llvm/IR/BasicBlock.h"
31#include "llvm/IR/CFG.h"
32#include "llvm/IR/Constant.h"
33#include "llvm/IR/Constants.h"
34#include "llvm/IR/DIBuilder.h"
35#include "llvm/IR/DataLayout.h"
36#include "llvm/IR/DebugInfoMetadata.h"
37#include "llvm/IR/DerivedTypes.h"
38#include "llvm/IR/Dominators.h"
39#include "llvm/IR/Function.h"
40#include "llvm/IR/GlobalValue.h"
41#include "llvm/IR/InstIterator.h"
42#include "llvm/IR/InstrTypes.h"
43#include "llvm/IR/Instruction.h"
44#include "llvm/IR/Instructions.h"
45#include "llvm/IR/IntrinsicInst.h"
46#include "llvm/IR/Intrinsics.h"
47#include "llvm/IR/LLVMContext.h"
48#include "llvm/IR/MDBuilder.h"
49#include "llvm/IR/Module.h"
50#include "llvm/IR/PatternMatch.h"
51#include "llvm/IR/Type.h"
52#include "llvm/IR/User.h"
53#include "llvm/IR/Value.h"
54#include "llvm/IR/Verifier.h"
55#include "llvm/Pass.h"
56#include "llvm/Support/BlockFrequency.h"
57#include "llvm/Support/BranchProbability.h"
58#include "llvm/Support/Casting.h"
59#include "llvm/Support/CommandLine.h"
60#include "llvm/Support/Debug.h"
61#include "llvm/Support/ErrorHandling.h"
62#include "llvm/Support/raw_ostream.h"
63#include "llvm/Transforms/Utils/BasicBlockUtils.h"
64#include "llvm/Transforms/Utils/Local.h"
65#include <cassert>
66#include <cstdint>
67#include <iterator>
68#include <map>
69#include <set>
70#include <utility>
71#include <vector>

73using namespace llvm;
74using namespace llvm::PatternMatch;
75using ProfileCount = Function::ProfileCount;

77#define DEBUG_TYPE"code-extractor" "code-extractor"

79// Provide a command-line option to aggregate function arguments into a struct
80// for functions produced by the code extractor. This is useful when converting
81// extracted functions to pthread-based code, as only one argument (void*) can
82// be passed in to pthread_create().
83static cl::opt<bool>
84AggregateArgsOpt("aggregate-extracted-args", cl::Hidden,
               cl::desc("Aggregate arguments to code-extracted functions"));

87/// Test whether a block is valid for extraction.
88static bool isBlockValidForExtraction(const BasicBlock &BB,
                                    const SetVector<BasicBlock *> &Result,
                                    bool AllowVarArgs, bool AllowAlloca) {
// taking the address of a basic block moved to another function is illegal
if (BB.hasAddressTaken())
  return false;

// don't hoist code that uses another basicblock address, as it's likely to
// lead to unexpected behavior, like cross-function jumps
SmallPtrSet<User const *, 16> Visited;
SmallVector<User const *, 16> ToVisit;

for (Instruction const &Inst : BB)
  ToVisit.push_back(&Inst);

while (!ToVisit.empty()) {
  User const *Curr = ToVisit.pop_back_val();
  if (!Visited.insert(Curr).second)
    continue;
  if (isa<BlockAddress const>(Curr))
    return false; // even a reference to self is likely to be not compatible

  if (isa<Instruction>(Curr) && cast<Instruction>(Curr)->getParent() != &BB)
    continue;

  for (auto const &U : Curr->operands()) {
    if (auto *UU = dyn_cast<User>(U))
      ToVisit.push_back(UU);
  }
}

// If explicitly requested, allow vastart and alloca. For invoke instructions
// verify that extraction is valid.
for (BasicBlock::const_iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
  if (isa<AllocaInst>(I)) {
     if (!AllowAlloca)
       return false;
     continue;
  }

  if (const auto *II = dyn_cast<InvokeInst>(I)) {
    // Unwind destination (either a landingpad, catchswitch, or cleanuppad)
    // must be a part of the subgraph which is being extracted.
    if (auto *UBB = II->getUnwindDest())
      if (!Result.count(UBB))
        return false;
    continue;
  }

  // All catch handlers of a catchswitch instruction as well as the unwind
  // destination must be in the subgraph.
  if (const auto *CSI = dyn_cast<CatchSwitchInst>(I)) {
    if (auto *UBB = CSI->getUnwindDest())
      if (!Result.count(UBB))
        return false;
    for (auto *HBB : CSI->handlers())
      if (!Result.count(const_cast<BasicBlock*>(HBB)))
        return false;
    continue;
  }

  // Make sure that entire catch handler is within subgraph. It is sufficient
  // to check that catch return's block is in the list.
  if (const auto *CPI = dyn_cast<CatchPadInst>(I)) {
    for (const auto *U : CPI->users())
      if (const auto *CRI = dyn_cast<CatchReturnInst>(U))
        if (!Result.count(const_cast<BasicBlock*>(CRI->getParent())))
          return false;
    continue;
  }

  // And do similar checks for cleanup handler - the entire handler must be
  // in subgraph which is going to be extracted. For cleanup return should
  // additionally check that the unwind destination is also in the subgraph.
  if (const auto *CPI = dyn_cast<CleanupPadInst>(I)) {
    for (const auto *U : CPI->users())
      if (const auto *CRI = dyn_cast<CleanupReturnInst>(U))
        if (!Result.count(const_cast<BasicBlock*>(CRI->getParent())))
          return false;
    continue;
  }
  if (const auto *CRI = dyn_cast<CleanupReturnInst>(I)) {
    if (auto *UBB = CRI->getUnwindDest())
      if (!Result.count(UBB))
        return false;
    continue;
  }

  if (const CallInst *CI = dyn_cast<CallInst>(I)) {
    if (const Function *F = CI->getCalledFunction()) {
      auto IID = F->getIntrinsicID();
      if (IID == Intrinsic::vastart) {
        if (AllowVarArgs)
          continue;
        else
          return false;
      }

      // Currently, we miscompile outlined copies of eh_typid_for. There are
      // proposals for fixing this in llvm.org/PR39545.
      if (IID == Intrinsic::eh_typeid_for)
        return false;
    }
  }
}

return true;
195}

197/// Build a set of blocks to extract if the input blocks are viable.
198static SetVector<BasicBlock *>
199buildExtractionBlockSet(ArrayRef<BasicBlock *> BBs, DominatorTree *DT,
                      bool AllowVarArgs, bool AllowAlloca) {
assert(!BBs.empty() && "The set of blocks to extract must be non-empty")((!BBs.empty() && "The set of blocks to extract must be non-empty"
) ? static_cast<void> (0) : __assert_fail ("!BBs.empty() && \"The set of blocks to extract must be non-empty\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 201, __PRETTY_FUNCTION__));
SetVector<BasicBlock *> Result;

// Loop over the blocks, adding them to our set-vector, and aborting with an
// empty set if we encounter invalid blocks.
for (BasicBlock *BB : BBs) {
  // If this block is dead, don't process it.
  if (DT && !DT->isReachableFromEntry(BB))
    continue;

  if (!Result.insert(BB))
    llvm_unreachable("Repeated basic blocks in extraction input")::llvm::llvm_unreachable_internal("Repeated basic blocks in extraction input"
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 212);
}

LLVM_DEBUG(dbgs() << "Region front block: " << Result.front()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Region front block: " <<
 Result.front()->getName() << '\n'; } } while (false
)
                  << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Region front block: " <<
 Result.front()->getName() << '\n'; } } while (false
);

for (auto *BB : Result) {
  if (!isBlockValidForExtraction(*BB, Result, AllowVarArgs, AllowAlloca))
    return {};

  // Make sure that the first block is not a landing pad.
  if (BB == Result.front()) {
    if (BB->isEHPad()) {
      LLVM_DEBUG(dbgs() << "The first block cannot be an unwind block\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "The first block cannot be an unwind block\n"
; } } while (false);
      return {};
    }
    continue;
  }

  // All blocks other than the first must not have predecessors outside of
  // the subgraph which is being extracted.
  for (auto *PBB : predecessors(BB))
    if (!Result.count(PBB)) {
      LLVM_DEBUG(dbgs() << "No blocks in this region may have entries from "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "No blocks in this region may have entries from "
 "outside the region except for the first block!\n" << "Problematic source BB: "
 << BB->getName() << "\n" << "Problematic destination BB: "
 << PBB->getName() << "\n"; } } while (false)
                           "outside the region except for the first block!\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "No blocks in this region may have entries from "
 "outside the region except for the first block!\n" << "Problematic source BB: "
 << BB->getName() << "\n" << "Problematic destination BB: "
 << PBB->getName() << "\n"; } } while (false)
                        << "Problematic source BB: " << BB->getName() << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "No blocks in this region may have entries from "
 "outside the region except for the first block!\n" << "Problematic source BB: "
 << BB->getName() << "\n" << "Problematic destination BB: "
 << PBB->getName() << "\n"; } } while (false)
                        << "Problematic destination BB: " << PBB->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "No blocks in this region may have entries from "
 "outside the region except for the first block!\n" << "Problematic source BB: "
 << BB->getName() << "\n" << "Problematic destination BB: "
 << PBB->getName() << "\n"; } } while (false)
                        << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "No blocks in this region may have entries from "
 "outside the region except for the first block!\n" << "Problematic source BB: "
 << BB->getName() << "\n" << "Problematic destination BB: "
 << PBB->getName() << "\n"; } } while (false);
      return {};
    }
}

return Result;
245}

247CodeExtractor::CodeExtractor(ArrayRef<BasicBlock *> BBs, DominatorTree *DT,
                           bool AggregateArgs, BlockFrequencyInfo *BFI,
                           BranchProbabilityInfo *BPI, AssumptionCache *AC,
                           bool AllowVarArgs, bool AllowAlloca,
                           std::string Suffix)
  : DT(DT), AggregateArgs(AggregateArgs || AggregateArgsOpt), BFI(BFI),
    BPI(BPI), AC(AC), AllowVarArgs(AllowVarArgs),
    Blocks(buildExtractionBlockSet(BBs, DT, AllowVarArgs, AllowAlloca)),
    Suffix(Suffix) {}

257CodeExtractor::CodeExtractor(DominatorTree &DT, Loop &L, bool AggregateArgs,
                           BlockFrequencyInfo *BFI,
                           BranchProbabilityInfo *BPI, AssumptionCache *AC,
                           std::string Suffix)
  : DT(&DT), AggregateArgs(AggregateArgs || AggregateArgsOpt), BFI(BFI),
    BPI(BPI), AC(AC), AllowVarArgs(false),
    Blocks(buildExtractionBlockSet(L.getBlocks(), &DT,
                                   /* AllowVarArgs */ false,
                                   /* AllowAlloca */ false)),
    Suffix(Suffix) {}

268/// definedInRegion - Return true if the specified value is defined in the
269/// extracted region.
270static bool definedInRegion(const SetVector<BasicBlock *> &Blocks, Value *V) {
if (Instruction *I = dyn_cast<Instruction>(V))
  if (Blocks.count(I->getParent()))
    return true;
return false;
275}

277/// definedInCaller - Return true if the specified value is defined in the
278/// function being code extracted, but not in the region being extracted.
279/// These values must be passed in as live-ins to the function.
280static bool definedInCaller(const SetVector<BasicBlock *> &Blocks, Value *V) {
if (isa<Argument>(V)) return true;
if (Instruction *I = dyn_cast<Instruction>(V))
  if (!Blocks.count(I->getParent()))
    return true;
return false;
286}

288static BasicBlock *getCommonExitBlock(const SetVector<BasicBlock *> &Blocks) {
BasicBlock *CommonExitBlock = nullptr;
auto hasNonCommonExitSucc = [&](BasicBlock *Block) {
  for (auto *Succ : successors(Block)) {
    // Internal edges, ok.
    if (Blocks.count(Succ))
      continue;
    if (!CommonExitBlock) {
      CommonExitBlock = Succ;
      continue;
    }
    if (CommonExitBlock != Succ)
      return true;
  }
  return false;
};

if (any_of(Blocks, hasNonCommonExitSucc))
  return nullptr;

return CommonExitBlock;
309}

311CodeExtractorAnalysisCache::CodeExtractorAnalysisCache(Function &F) {
for (BasicBlock &BB : F) {
  for (Instruction &II : BB.instructionsWithoutDebug())
    if (auto *AI = dyn_cast<AllocaInst>(&II))
      Allocas.push_back(AI);

  findSideEffectInfoForBlock(BB);
}
319}

321void CodeExtractorAnalysisCache::findSideEffectInfoForBlock(BasicBlock &BB) {
for (Instruction &II : BB.instructionsWithoutDebug()) {
  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 (isa<Constant>(MemAddr))
      break;
    Value *Base = MemAddr->stripInBoundsConstantOffsets();
    if (!isa<AllocaInst>(Base)) {
      SideEffectingBlocks.insert(&BB);
      return;
    }
    BaseMemAddrs[&BB].insert(Base);
    break;
  }
  default: {
    IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(&II);
    if (IntrInst) {
      if (IntrInst->isLifetimeStartOrEnd())
        break;
      SideEffectingBlocks.insert(&BB);
      return;
    }
    // Treat all the other cases conservatively if it has side effects.
    if (II.mayHaveSideEffects()) {
      SideEffectingBlocks.insert(&BB);
      return;
    }
  }
  }
}
362}

364bool CodeExtractorAnalysisCache::doesBlockContainClobberOfAddr(
  BasicBlock &BB, AllocaInst *Addr) const {
if (SideEffectingBlocks.count(&BB))
  return true;
auto It = BaseMemAddrs.find(&BB);
if (It != BaseMemAddrs.end())
  return It->second.count(Addr);
return false;
372}

374bool CodeExtractor::isLegalToShrinkwrapLifetimeMarkers(
  const CodeExtractorAnalysisCache &CEAC, Instruction *Addr) const {
AllocaInst *AI = cast<AllocaInst>(Addr->stripInBoundsConstantOffsets());
Function *Func = (*Blocks.begin())->getParent();
for (BasicBlock &BB : *Func) {
  if (Blocks.count(&BB))
    continue;
  if (CEAC.doesBlockContainClobberOfAddr(BB, AI))
    return false;
}
return true;
385}

387BasicBlock *
388CodeExtractor::findOrCreateBlockForHoisting(BasicBlock *CommonExitBlock) {
BasicBlock *SinglePredFromOutlineRegion = nullptr;
assert(!Blocks.count(CommonExitBlock) &&((!Blocks.count(CommonExitBlock) && "Expect a block outside the region!"
) ? static_cast<void> (0) : __assert_fail ("!Blocks.count(CommonExitBlock) && \"Expect a block outside the region!\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 391, __PRETTY_FUNCTION__))
       "Expect a block outside the region!")((!Blocks.count(CommonExitBlock) && "Expect a block outside the region!"
) ? static_cast<void> (0) : __assert_fail ("!Blocks.count(CommonExitBlock) && \"Expect a block outside the region!\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 391, __PRETTY_FUNCTION__));
for (auto *Pred : predecessors(CommonExitBlock)) {
  if (!Blocks.count(Pred))
    continue;
  if (!SinglePredFromOutlineRegion) {
    SinglePredFromOutlineRegion = Pred;
  } else if (SinglePredFromOutlineRegion != Pred) {
    SinglePredFromOutlineRegion = nullptr;
    break;
  }
}

if (SinglePredFromOutlineRegion)
  return SinglePredFromOutlineRegion;

406#ifndef NDEBUG
auto getFirstPHI = [](BasicBlock *BB) {
  BasicBlock::iterator I = BB->begin();
  PHINode *FirstPhi = nullptr;
  while (I != BB->end()) {
    PHINode *Phi = dyn_cast<PHINode>(I);
    if (!Phi)
      break;
    if (!FirstPhi) {
      FirstPhi = Phi;
      break;
    }
  }
  return FirstPhi;
};
// If there are any phi nodes, the single pred either exists or has already
// be created before code extraction.
assert(!getFirstPHI(CommonExitBlock) && "Phi not expected")((!getFirstPHI(CommonExitBlock) && "Phi not expected"
) ? static_cast<void> (0) : __assert_fail ("!getFirstPHI(CommonExitBlock) && \"Phi not expected\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 423, __PRETTY_FUNCTION__));
424#endif

BasicBlock *NewExitBlock = CommonExitBlock->splitBasicBlock(
    CommonExitBlock->getFirstNonPHI()->getIterator());

for (BasicBlock *Pred :
     llvm::make_early_inc_range(predecessors(CommonExitBlock))) {
  if (Blocks.count(Pred))
    continue;
  Pred->getTerminator()->replaceUsesOfWith(CommonExitBlock, NewExitBlock);
}
// Now add the old exit block to the outline region.
Blocks.insert(CommonExitBlock);
return CommonExitBlock;
438}

440// Find the pair of life time markers for address 'Addr' that are either
441// defined inside the outline region or can legally be shrinkwrapped into the
442// outline region. If there are not other untracked uses of the address, return
443// the pair of markers if found; otherwise return a pair of nullptr.
444CodeExtractor::LifetimeMarkerInfo
445CodeExtractor::getLifetimeMarkers(const CodeExtractorAnalysisCache &CEAC,
                                Instruction *Addr,
                                BasicBlock *ExitBlock) const {
LifetimeMarkerInfo Info;

for (User *U : Addr->users()) {
  IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(U);
  if (IntrInst) {
    // We don't model addresses with multiple start/end markers, but the
    // markers do not need to be in the region.
    if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_start) {
      if (Info.LifeStart)
        return {};
      Info.LifeStart = IntrInst;
      continue;
    }
    if (IntrInst->getIntrinsicID() == Intrinsic::lifetime_end) {
      if (Info.LifeEnd)
        return {};
      Info.LifeEnd = IntrInst;
      continue;
    }
    // At this point, permit debug uses outside of the region.
    // This is fixed in a later call to fixupDebugInfoPostExtraction().
    if (isa<DbgInfoIntrinsic>(IntrInst))
      continue;
  }
  // Find untracked uses of the address, bail.
  if (!definedInRegion(Blocks, U))
    return {};
}

if (!Info.LifeStart || !Info.LifeEnd)
  return {};

Info.SinkLifeStart = !definedInRegion(Blocks, Info.LifeStart);
Info.HoistLifeEnd = !definedInRegion(Blocks, Info.LifeEnd);
// Do legality check.
if ((Info.SinkLifeStart || Info.HoistLifeEnd) &&
    !isLegalToShrinkwrapLifetimeMarkers(CEAC, Addr))
  return {};

// Check to see if we have a place to do hoisting, if not, bail.
if (Info.HoistLifeEnd && !ExitBlock)
  return {};

return Info;
492}

494void CodeExtractor::findAllocas(const CodeExtractorAnalysisCache &CEAC,
                              ValueSet &SinkCands, ValueSet &HoistCands,
                              BasicBlock *&ExitBlock) const {
Function *Func = (*Blocks.begin())->getParent();
ExitBlock = getCommonExitBlock(Blocks);

auto moveOrIgnoreLifetimeMarkers =
    [&](const LifetimeMarkerInfo &LMI) -> bool {
  if (!LMI.LifeStart)
    return false;
  if (LMI.SinkLifeStart) {
    LLVM_DEBUG(dbgs() << "Sinking lifetime.start: " << *LMI.LifeStartdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking lifetime.start: "
 << *LMI.LifeStart << "\n"; } } while (false)
                      << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking lifetime.start: "
 << *LMI.LifeStart << "\n"; } } while (false);
    SinkCands.insert(LMI.LifeStart);
  }
  if (LMI.HoistLifeEnd) {
    LLVM_DEBUG(dbgs() << "Hoisting lifetime.end: " << *LMI.LifeEnd << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Hoisting lifetime.end: "
 << *LMI.LifeEnd << "\n"; } } while (false);
    HoistCands.insert(LMI.LifeEnd);
  }
  return true;
};

// Look up allocas in the original function in CodeExtractorAnalysisCache, as
// this is much faster than walking all the instructions.
for (AllocaInst *AI : CEAC.getAllocas()) {
  BasicBlock *BB = AI->getParent();
  if (Blocks.count(BB))
    continue;

  // As a prior call to extractCodeRegion() may have shrinkwrapped the alloca,
  // check whether it is actually still in the original function.
  Function *AIFunc = BB->getParent();
  if (AIFunc != Func)
    continue;

  LifetimeMarkerInfo MarkerInfo = getLifetimeMarkers(CEAC, AI, ExitBlock);
  bool Moved = moveOrIgnoreLifetimeMarkers(MarkerInfo);
  if (Moved) {
    LLVM_DEBUG(dbgs() << "Sinking alloca: " << *AI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking alloca: " <<
 *AI << "\n"; } } while (false);
    SinkCands.insert(AI);
    continue;
  }

  // Find bitcasts in the outlined region that have lifetime marker users
  // outside that region. Replace the lifetime marker use with an
  // outside region bitcast to avoid unnecessary alloca/reload instructions
  // and extra lifetime markers.
  SmallVector<Instruction *, 2> LifetimeBitcastUsers;
  for (User *U : AI->users()) {
    if (!definedInRegion(Blocks, U))
      continue;

    if (U->stripInBoundsConstantOffsets() != AI)
      continue;

    Instruction *Bitcast = cast<Instruction>(U);
    for (User *BU : Bitcast->users()) {
      IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(BU);
      if (!IntrInst)
        continue;

      if (!IntrInst->isLifetimeStartOrEnd())
        continue;

      if (definedInRegion(Blocks, IntrInst))
        continue;

      LLVM_DEBUG(dbgs() << "Replace use of extracted region bitcast"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Replace use of extracted region bitcast"
 << *Bitcast << " in out-of-region lifetime marker "
 << *IntrInst << "\n"; } } while (false)
                        << *Bitcast << " in out-of-region lifetime marker "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Replace use of extracted region bitcast"
 << *Bitcast << " in out-of-region lifetime marker "
 << *IntrInst << "\n"; } } while (false)
                        << *IntrInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Replace use of extracted region bitcast"
 << *Bitcast << " in out-of-region lifetime marker "
 << *IntrInst << "\n"; } } while (false);
      LifetimeBitcastUsers.push_back(IntrInst);
    }
  }

  for (Instruction *I : LifetimeBitcastUsers) {
    Module *M = AIFunc->getParent();
    LLVMContext &Ctx = M->getContext();
    auto *Int8PtrTy = Type::getInt8PtrTy(Ctx);
    CastInst *CastI =
        CastInst::CreatePointerCast(AI, Int8PtrTy, "lt.cast", I);
    I->replaceUsesOfWith(I->getOperand(1), CastI);
  }

  // Follow any bitcasts.
  SmallVector<Instruction *, 2> Bitcasts;
  SmallVector<LifetimeMarkerInfo, 2> BitcastLifetimeInfo;
  for (User *U : AI->users()) {
    if (U->stripInBoundsConstantOffsets() == AI) {
      Instruction *Bitcast = cast<Instruction>(U);
      LifetimeMarkerInfo LMI = getLifetimeMarkers(CEAC, Bitcast, ExitBlock);
      if (LMI.LifeStart) {
        Bitcasts.push_back(Bitcast);
        BitcastLifetimeInfo.push_back(LMI);
        continue;
      }
    }

    // Found unknown use of AI.
    if (!definedInRegion(Blocks, U)) {
      Bitcasts.clear();
      break;
    }
  }

  // Either no bitcasts reference the alloca or there are unknown uses.
  if (Bitcasts.empty())
    continue;

  LLVM_DEBUG(dbgs() << "Sinking alloca (via bitcast): " << *AI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking alloca (via bitcast): "
 << *AI << "\n"; } } while (false);
  SinkCands.insert(AI);
  for (unsigned I = 0, E = Bitcasts.size(); I != E; ++I) {
    Instruction *BitcastAddr = Bitcasts[I];
    const LifetimeMarkerInfo &LMI = BitcastLifetimeInfo[I];
    assert(LMI.LifeStart &&((LMI.LifeStart && "Unsafe to sink bitcast without lifetime markers"
) ? static_cast<void> (0) : __assert_fail ("LMI.LifeStart && \"Unsafe to sink bitcast without lifetime markers\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 608, __PRETTY_FUNCTION__))
           "Unsafe to sink bitcast without lifetime markers")((LMI.LifeStart && "Unsafe to sink bitcast without lifetime markers"
) ? static_cast<void> (0) : __assert_fail ("LMI.LifeStart && \"Unsafe to sink bitcast without lifetime markers\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 608, __PRETTY_FUNCTION__));
    moveOrIgnoreLifetimeMarkers(LMI);
    if (!definedInRegion(Blocks, BitcastAddr)) {
      LLVM_DEBUG(dbgs() << "Sinking bitcast-of-alloca: " << *BitcastAddrdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking bitcast-of-alloca: "
 << *BitcastAddr << "\n"; } } while (false)
                        << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "Sinking bitcast-of-alloca: "
 << *BitcastAddr << "\n"; } } while (false);
      SinkCands.insert(BitcastAddr);
    }
  }
}
617}

619bool CodeExtractor::isEligible() const {
if (Blocks.empty())
  return false;
BasicBlock *Header = *Blocks.begin();
Function *F = Header->getParent();

// For functions with varargs, check that varargs handling is only done in the
// outlined function, i.e vastart and vaend are only used in outlined blocks.
if (AllowVarArgs && F->getFunctionType()->isVarArg()) {
  auto containsVarArgIntrinsic = [](const Instruction &I) {
    if (const CallInst *CI = dyn_cast<CallInst>(&I))
      if (const Function *Callee = CI->getCalledFunction())
        return Callee->getIntrinsicID() == Intrinsic::vastart ||
               Callee->getIntrinsicID() == Intrinsic::vaend;
    return false;
  };

  for (auto &BB : *F) {
    if (Blocks.count(&BB))
      continue;
    if (llvm::any_of(BB, containsVarArgIntrinsic))
      return false;
  }
}
return true;
644}

646void CodeExtractor::findInputsOutputs(ValueSet &Inputs, ValueSet &Outputs,
                                    const ValueSet &SinkCands) const {
for (BasicBlock *BB : Blocks) {
  // If a used value is defined outside the region, it's an input.  If an
  // instruction is used outside the region, it's an output.
  for (Instruction &II : *BB) {
    for (auto &OI : II.operands()) {
      Value *V = OI;
      if (!SinkCands.count(V) && definedInCaller(Blocks, V))
        Inputs.insert(V);
    }

    for (User *U : II.users())
      if (!definedInRegion(Blocks, U)) {
        Outputs.insert(&II);
        break;
      }
  }
}
665}

667/// severSplitPHINodesOfEntry - If a PHI node has multiple inputs from outside
668/// of the region, we need to split the entry block of the region so that the
669/// PHI node is easier to deal with.
670void CodeExtractor::severSplitPHINodesOfEntry(BasicBlock *&Header) {
unsigned NumPredsFromRegion = 0;
unsigned NumPredsOutsideRegion = 0;

if (Header != &Header->getParent()->getEntryBlock()) {
  PHINode *PN = dyn_cast<PHINode>(Header->begin());
  if (!PN) return;  // No PHI nodes.

  // If the header node contains any PHI nodes, check to see if there is more
  // than one entry from outside the region.  If so, we need to sever the
  // header block into two.
  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
    if (Blocks.count(PN->getIncomingBlock(i)))
      ++NumPredsFromRegion;
    else
      ++NumPredsOutsideRegion;

  // If there is one (or fewer) predecessor from outside the region, we don't
  // need to do anything special.
  if (NumPredsOutsideRegion <= 1) return;
}

// Otherwise, we need to split the header block into two pieces: one
// containing PHI nodes merging values from outside of the region, and a
// second that contains all of the code for the block and merges back any
// incoming values from inside of the region.
BasicBlock *NewBB = SplitBlock(Header, Header->getFirstNonPHI(), DT);

// We only want to code extract the second block now, and it becomes the new
// header of the region.
BasicBlock *OldPred = Header;
Blocks.remove(OldPred);
Blocks.insert(NewBB);
Header = NewBB;

// Okay, now we need to adjust the PHI nodes and any branches from within the
// region to go to the new header block instead of the old header block.
if (NumPredsFromRegion) {
  PHINode *PN = cast<PHINode>(OldPred->begin());
  // Loop over all of the predecessors of OldPred that are in the region,
  // changing them to branch to NewBB instead.
  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
    if (Blocks.count(PN->getIncomingBlock(i))) {
      Instruction *TI = PN->getIncomingBlock(i)->getTerminator();
      TI->replaceUsesOfWith(OldPred, NewBB);
    }

  // Okay, everything within the region is now branching to the right block, we
  // just have to update the PHI nodes now, inserting PHI nodes into NewBB.
  BasicBlock::iterator AfterPHIs;
  for (AfterPHIs = OldPred->begin(); isa<PHINode>(AfterPHIs); ++AfterPHIs) {
    PHINode *PN = cast<PHINode>(AfterPHIs);
    // Create a new PHI node in the new region, which has an incoming value
    // from OldPred of PN.
    PHINode *NewPN = PHINode::Create(PN->getType(), 1 + NumPredsFromRegion,
                                     PN->getName() + ".ce", &NewBB->front());
    PN->replaceAllUsesWith(NewPN);
    NewPN->addIncoming(PN, OldPred);

    // Loop over all of the incoming value in PN, moving them to NewPN if they
    // are from the extracted region.
    for (unsigned i = 0; i != PN->getNumIncomingValues(); ++i) {
      if (Blocks.count(PN->getIncomingBlock(i))) {
        NewPN->addIncoming(PN->getIncomingValue(i), PN->getIncomingBlock(i));
        PN->removeIncomingValue(i);
        --i;
      }
    }
  }
}
740}

742/// severSplitPHINodesOfExits - if PHI nodes in exit blocks have inputs from
743/// outlined region, we split these PHIs on two: one with inputs from region
744/// and other with remaining incoming blocks; then first PHIs are placed in
745/// outlined region.
746void CodeExtractor::severSplitPHINodesOfExits(
  const SmallPtrSetImpl<BasicBlock *> &Exits) {
for (BasicBlock *ExitBB : Exits) {
  BasicBlock *NewBB = nullptr;

  for (PHINode &PN : ExitBB->phis()) {
    // Find all incoming values from the outlining region.
    SmallVector<unsigned, 2> IncomingVals;
    for (unsigned i = 0; i < PN.getNumIncomingValues(); ++i)
      if (Blocks.count(PN.getIncomingBlock(i)))
        IncomingVals.push_back(i);

    // Do not process PHI if there is one (or fewer) predecessor from region.
    // If PHI has exactly one predecessor from region, only this one incoming
    // will be replaced on codeRepl block, so it should be safe to skip PHI.
    if (IncomingVals.size() <= 1)
      continue;

    // Create block for new PHIs and add it to the list of outlined if it
    // wasn't done before.
    if (!NewBB) {
      NewBB = BasicBlock::Create(ExitBB->getContext(),
                                 ExitBB->getName() + ".split",
                                 ExitBB->getParent(), ExitBB);
      SmallVector<BasicBlock *, 4> Preds(predecessors(ExitBB));
      for (BasicBlock *PredBB : Preds)
        if (Blocks.count(PredBB))
          PredBB->getTerminator()->replaceUsesOfWith(ExitBB, NewBB);
      BranchInst::Create(ExitBB, NewBB);
      Blocks.insert(NewBB);
    }

    // Split this PHI.
    PHINode *NewPN =
        PHINode::Create(PN.getType(), IncomingVals.size(),
                        PN.getName() + ".ce", NewBB->getFirstNonPHI());
    for (unsigned i : IncomingVals)
      NewPN->addIncoming(PN.getIncomingValue(i), PN.getIncomingBlock(i));
    for (unsigned i : reverse(IncomingVals))
      PN.removeIncomingValue(i, false);
    PN.addIncoming(NewPN, NewBB);
  }
}
789}

791void CodeExtractor::splitReturnBlocks() {
for (BasicBlock *Block : Blocks)
  if (ReturnInst *RI = dyn_cast<ReturnInst>(Block->getTerminator())) {
    BasicBlock *New =
        Block->splitBasicBlock(RI->getIterator(), Block->getName() + ".ret");
    if (DT) {
      // Old dominates New. New node dominates all other nodes dominated
      // by Old.
      DomTreeNode *OldNode = DT->getNode(Block);
      SmallVector<DomTreeNode *, 8> Children(OldNode->begin(),
                                             OldNode->end());

      DomTreeNode *NewNode = DT->addNewBlock(New, Block);

      for (DomTreeNode *I : Children)
        DT->changeImmediateDominator(I, NewNode);
    }
  }
809}

811/// constructFunction - make a function based on inputs and outputs, as follows:
812/// f(in0, ..., inN, out0, ..., outN)
813Function *CodeExtractor::constructFunction(const ValueSet &inputs,
                                         const ValueSet &outputs,
                                         BasicBlock *header,
                                         BasicBlock *newRootNode,
                                         BasicBlock *newHeader,
                                         Function *oldFunction,
                                         Module *M) {
LLVM_DEBUG(dbgs() << "inputs: " << inputs.size() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "inputs: " << inputs
.size() << "\n"; } } while (false);
1
Assuming 'DebugFlag' is false→
2
←
Loop condition is false.  Exiting loop→
LLVM_DEBUG(dbgs() << "outputs: " << outputs.size() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "outputs: " << outputs
.size() << "\n"; } } while (false);
3
←
Loop condition is false.  Exiting loop→

// This function returns unsigned, outputs will go back by reference.
switch (NumExitBlocks) {
4
←
Control jumps to the 'default' case at line 828→
case 0:
case 1: RetTy = Type::getVoidTy(header->getContext()); break;
case 2: RetTy = Type::getInt1Ty(header->getContext()); break;
default: RetTy = Type::getInt16Ty(header->getContext()); break;
5
←
 Execution continues on line 831→
}

std::vector<Type *> paramTy;

// Add the types of the input values to the function's argument list
for (Value *value : inputs) {
  LLVM_DEBUG(dbgs() << "value used in func: " << *value << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "value used in func: " <<
 *value << "\n"; } } while (false);
  paramTy.push_back(value->getType());
}

// Add the types of the output values to the function's argument list.
for (Value *output : outputs) {
  LLVM_DEBUG(dbgs() << "instr used in func: " << *output << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { dbgs() << "instr used in func: " <<
 *output << "\n"; } } while (false);
  if (AggregateArgs)
    paramTy.push_back(output->getType());
  else
    paramTy.push_back(PointerType::getUnqual(output->getType()));
}

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
)
6
←
Assuming 'DebugFlag' is false→
7
←
Loop condition is false.  Exiting loop→
  dbgs() << "Function type: " << *RetTy << " f(";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
)
  for (Type *i : paramTy)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
)
    dbgs() << *i << ", ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
)
  dbgs() << ")\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { { dbgs() << "Function type: " <<
 *RetTy << " f("; for (Type *i : paramTy) dbgs() <<
 *i << ", "; dbgs() << ")\n"; }; } } while (false
);

StructType *StructTy = nullptr;
8
←
'StructTy' initialized to a null pointer value→
if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
9
←
Assuming field 'AggregateArgs' is true→
10
←
Assuming the condition is false→
11
←
Taking false branch→
  StructTy = StructType::get(M->getContext(), paramTy);
  paramTy.clear();
  paramTy.push_back(PointerType::getUnqual(StructTy));
}
FunctionType *funcType =
                FunctionType::get(RetTy, paramTy,
                                  AllowVarArgs && oldFunction->isVarArg());
12
←
Assuming field 'AllowVarArgs' is false→

std::string SuffixToUse =
    Suffix.empty()
13
←
Assuming the condition is false→
14
←
'?' condition is false→
        ? (header->getName().empty() ? "extracted" : header->getName().str())
        : Suffix;
// Create the new function
Function *newFunction = Function::Create(
    funcType, GlobalValue::InternalLinkage, oldFunction->getAddressSpace(),
    oldFunction->getName() + "." + SuffixToUse, M);
// If the old function is no-throw, so is the new one.
if (oldFunction->doesNotThrow())
15
←
Assuming the condition is false→
16
←
Taking false branch→
  newFunction->setDoesNotThrow();

// Inherit the uwtable attribute if we need to.
if (oldFunction->hasUWTable())
17
←
Assuming the condition is false→
18
←
Taking false branch→
  newFunction->setHasUWTable();

// Inherit all of the target dependent attributes and white-listed
// target independent attributes.
//  (e.g. If the extracted region contains a call to an x86.sse
//  instruction we need to make sure that the extracted region has the
//  "target-features" attribute allowing it to be lowered.
// FIXME: This should be changed to check to see if a specific
//           attribute can not be inherited.
for (const auto &Attr : oldFunction->getAttributes().getFnAttributes()) {
19
←
Assuming '__begin1' is equal to '__end1'→
  if (Attr.isStringAttribute()) {
    if (Attr.getKindAsString() == "thunk")
      continue;
  } else
    switch (Attr.getKindAsEnum()) {
    // Those attributes cannot be propagated safely. Explicitly list them
    // here so we get a warning if new attributes are added. This list also
    // includes non-function attributes.
    case Attribute::Alignment:
    case Attribute::AllocSize:
    case Attribute::ArgMemOnly:
    case Attribute::Builtin:
    case Attribute::ByVal:
    case Attribute::Convergent:
    case Attribute::Dereferenceable:
    case Attribute::DereferenceableOrNull:
    case Attribute::InAlloca:
    case Attribute::InReg:
    case Attribute::InaccessibleMemOnly:
    case Attribute::InaccessibleMemOrArgMemOnly:
    case Attribute::JumpTable:
    case Attribute::Naked:
    case Attribute::Nest:
    case Attribute::NoAlias:
    case Attribute::NoBuiltin:
    case Attribute::NoCapture:
    case Attribute::NoMerge:
    case Attribute::NoReturn:
    case Attribute::NoSync:
    case Attribute::NoUndef:
    case Attribute::None:
    case Attribute::NonNull:
    case Attribute::Preallocated:
    case Attribute::ReadNone:
    case Attribute::ReadOnly:
    case Attribute::Returned:
    case Attribute::ReturnsTwice:
    case Attribute::SExt:
    case Attribute::Speculatable:
    case Attribute::StackAlignment:
    case Attribute::StructRet:
    case Attribute::SwiftError:
    case Attribute::SwiftSelf:
    case Attribute::WillReturn:
    case Attribute::WriteOnly:
    case Attribute::ZExt:
    case Attribute::ImmArg:
    case Attribute::ByRef:
    case Attribute::EndAttrKinds:
    case Attribute::EmptyKey:
    case Attribute::TombstoneKey:
      continue;
    // Those attributes should be safe to propagate to the extracted function.
    case Attribute::AlwaysInline:
    case Attribute::Cold:
    case Attribute::Hot:
    case Attribute::NoRecurse:
    case Attribute::InlineHint:
    case Attribute::MinSize:
    case Attribute::NoCallback:
    case Attribute::NoDuplicate:
    case Attribute::NoFree:
    case Attribute::NoImplicitFloat:
    case Attribute::NoInline:
    case Attribute::NonLazyBind:
    case Attribute::NoRedZone:
    case Attribute::NoUnwind:
    case Attribute::NullPointerIsValid:
    case Attribute::OptForFuzzing:
    case Attribute::OptimizeNone:
    case Attribute::OptimizeForSize:
    case Attribute::SafeStack:
    case Attribute::ShadowCallStack:
    case Attribute::SanitizeAddress:
    case Attribute::SanitizeMemory:
    case Attribute::SanitizeThread:
    case Attribute::SanitizeHWAddress:
    case Attribute::SanitizeMemTag:
    case Attribute::SpeculativeLoadHardening:
    case Attribute::StackProtect:
    case Attribute::StackProtectReq:
    case Attribute::StackProtectStrong:
    case Attribute::StrictFP:
    case Attribute::UWTable:
    case Attribute::NoCfCheck:
    case Attribute::MustProgress:
    case Attribute::NoProfile:
      break;
    }

  newFunction->addFnAttr(Attr);
}
newFunction->getBasicBlockList().push_back(newRootNode);

// Create an iterator to name all of the arguments we inserted.
Function::arg_iterator AI = newFunction->arg_begin();

// Rewrite all users of the inputs in the extracted region to use the
// arguments (or appropriate addressing into struct) instead.
for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
20
←
Assuming 'i' is not equal to 'e'→
21
←
Loop condition is true.  Entering loop body→
  Value *RewriteVal;
  if (AggregateArgs21.1
Field 'AggregateArgs' is true
) {
22
←
Taking true branch→
    Value *Idx[2];
    Idx[0] = Constant::getNullValue(Type::getInt32Ty(header->getContext()));
    Idx[1] = ConstantInt::get(Type::getInt32Ty(header->getContext()), i);
    Instruction *TI = newFunction->begin()->getTerminator();
    GetElementPtrInst *GEP = GetElementPtrInst::Create(
        StructTy, &*AI, Idx, "gep_" + inputs[i]->getName(), TI);
    RewriteVal = new LoadInst(StructTy->getElementType(i), GEP,
23
←
Called C++ object pointer is null
                              "loadgep_" + inputs[i]->getName(), TI);
  } else
    RewriteVal = &*AI++;

  std::vector<User *> Users(inputs[i]->user_begin(), inputs[i]->user_end());
  for (User *use : Users)
    if (Instruction *inst = dyn_cast<Instruction>(use))
      if (Blocks.count(inst->getParent()))
        inst->replaceUsesOfWith(inputs[i], RewriteVal);
}

// Set names for input and output arguments.
if (!AggregateArgs) {
  AI = newFunction->arg_begin();
  for (unsigned i = 0, e = inputs.size(); i != e; ++i, ++AI)
    AI->setName(inputs[i]->getName());
  for (unsigned i = 0, e = outputs.size(); i != e; ++i, ++AI)
    AI->setName(outputs[i]->getName()+".out");
}

// Rewrite branches to basic blocks outside of the loop to new dummy blocks
// within the new function. This must be done before we lose track of which
// blocks were originally in the code region.
std::vector<User *> Users(header->user_begin(), header->user_end());
for (auto &U : Users)
  // The BasicBlock which contains the branch is not in the region
  // modify the branch target to a new block
  if (Instruction *I = dyn_cast<Instruction>(U))
    if (I->isTerminator() && I->getFunction() == oldFunction &&
        !Blocks.count(I->getParent()))
      I->replaceUsesOfWith(header, newHeader);

return newFunction;
1031}

1033/// Erase lifetime.start markers which reference inputs to the extraction
1034/// region, and insert the referenced memory into \p LifetimesStart.
1035///
1036/// The extraction region is defined by a set of blocks (\p Blocks), and a set
1037/// of allocas which will be moved from the caller function into the extracted
1038/// function (\p SunkAllocas).
1039static void eraseLifetimeMarkersOnInputs(const SetVector<BasicBlock *> &Blocks,
                                       const SetVector<Value *> &SunkAllocas,
                                       SetVector<Value *> &LifetimesStart) {
for (BasicBlock *BB : Blocks) {
  for (auto It = BB->begin(), End = BB->end(); It != End;) {
    auto *II = dyn_cast<IntrinsicInst>(&*It);
    ++It;
    if (!II || !II->isLifetimeStartOrEnd())
      continue;

    // Get the memory operand of the lifetime marker. If the underlying
    // object is a sunk alloca, or is otherwise defined in the extraction
    // region, the lifetime marker must not be erased.
    Value *Mem = II->getOperand(1)->stripInBoundsOffsets();
    if (SunkAllocas.count(Mem) || definedInRegion(Blocks, Mem))
      continue;

    if (II->getIntrinsicID() == Intrinsic::lifetime_start)
      LifetimesStart.insert(Mem);
    II->eraseFromParent();
  }
}
1061}

1063/// Insert lifetime start/end markers surrounding the call to the new function
1064/// for objects defined in the caller.
1065static void insertLifetimeMarkersSurroundingCall(
  Module *M, ArrayRef<Value *> LifetimesStart, ArrayRef<Value *> LifetimesEnd,
  CallInst *TheCall) {
LLVMContext &Ctx = M->getContext();
auto Int8PtrTy = Type::getInt8PtrTy(Ctx);
auto NegativeOne = ConstantInt::getSigned(Type::getInt64Ty(Ctx), -1);
Instruction *Term = TheCall->getParent()->getTerminator();

// The memory argument to a lifetime marker must be a i8*. Cache any bitcasts
// needed to satisfy this requirement so they may be reused.
DenseMap<Value *, Value *> Bitcasts;

// Emit lifetime markers for the pointers given in \p Objects. Insert the
// markers before the call if \p InsertBefore, and after the call otherwise.
auto insertMarkers = [&](Function *MarkerFunc, ArrayRef<Value *> Objects,
                         bool InsertBefore) {
  for (Value *Mem : Objects) {
    assert((!isa<Instruction>(Mem) || cast<Instruction>(Mem)->getFunction() ==(((!isa<Instruction>(Mem) || cast<Instruction>(Mem
)->getFunction() == TheCall->getFunction()) && "Input memory not defined in original function"
) ? static_cast<void> (0) : __assert_fail ("(!isa<Instruction>(Mem) || cast<Instruction>(Mem)->getFunction() == TheCall->getFunction()) && \"Input memory not defined in original function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1084, __PRETTY_FUNCTION__))
                                          TheCall->getFunction()) &&(((!isa<Instruction>(Mem) || cast<Instruction>(Mem
)->getFunction() == TheCall->getFunction()) && "Input memory not defined in original function"
) ? static_cast<void> (0) : __assert_fail ("(!isa<Instruction>(Mem) || cast<Instruction>(Mem)->getFunction() == TheCall->getFunction()) && \"Input memory not defined in original function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1084, __PRETTY_FUNCTION__))
           "Input memory not defined in original function")(((!isa<Instruction>(Mem) || cast<Instruction>(Mem
)->getFunction() == TheCall->getFunction()) && "Input memory not defined in original function"
) ? static_cast<void> (0) : __assert_fail ("(!isa<Instruction>(Mem) || cast<Instruction>(Mem)->getFunction() == TheCall->getFunction()) && \"Input memory not defined in original function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1084, __PRETTY_FUNCTION__));
    Value *&MemAsI8Ptr = Bitcasts[Mem];
    if (!MemAsI8Ptr) {
      if (Mem->getType() == Int8PtrTy)
        MemAsI8Ptr = Mem;
      else
        MemAsI8Ptr =
            CastInst::CreatePointerCast(Mem, Int8PtrTy, "lt.cast", TheCall);
    }

    auto Marker = CallInst::Create(MarkerFunc, {NegativeOne, MemAsI8Ptr});
    if (InsertBefore)
      Marker->insertBefore(TheCall);
    else
      Marker->insertBefore(Term);
  }
};

if (!LifetimesStart.empty()) {
  auto StartFn = llvm::Intrinsic::getDeclaration(
      M, llvm::Intrinsic::lifetime_start, Int8PtrTy);
  insertMarkers(StartFn, LifetimesStart, /*InsertBefore=*/true);
}

if (!LifetimesEnd.empty()) {
  auto EndFn = llvm::Intrinsic::getDeclaration(
      M, llvm::Intrinsic::lifetime_end, Int8PtrTy);
  insertMarkers(EndFn, LifetimesEnd, /*InsertBefore=*/false);
}
1113}

1115/// emitCallAndSwitchStatement - This method sets up the caller side by adding
1116/// the call instruction, splitting any PHI nodes in the header block as
1117/// necessary.
1118CallInst *CodeExtractor::emitCallAndSwitchStatement(Function *newFunction,
                                                  BasicBlock *codeReplacer,
                                                  ValueSet &inputs,
                                                  ValueSet &outputs) {
// Emit a call to the new function, passing in: *pointer to struct (if
// aggregating parameters), or plan inputs and allocated memory for outputs
std::vector<Value *> params, StructValues, ReloadOutputs, Reloads;

Module *M = newFunction->getParent();
LLVMContext &Context = M->getContext();
const DataLayout &DL = M->getDataLayout();
CallInst *call = nullptr;

// Add inputs as params, or to be filled into the struct
unsigned ArgNo = 0;
SmallVector<unsigned, 1> SwiftErrorArgs;
for (Value *input : inputs) {
  if (AggregateArgs)
    StructValues.push_back(input);
  else {
    params.push_back(input);
    if (input->isSwiftError())
      SwiftErrorArgs.push_back(ArgNo);
  }
  ++ArgNo;
}

// Create allocas for the outputs
for (Value *output : outputs) {
  if (AggregateArgs) {
    StructValues.push_back(output);
  } else {
    AllocaInst *alloca =
      new AllocaInst(output->getType(), DL.getAllocaAddrSpace(),
                     nullptr, output->getName() + ".loc",
                     &codeReplacer->getParent()->front().front());
    ReloadOutputs.push_back(alloca);
    params.push_back(alloca);
  }
}

StructType *StructArgTy = nullptr;
AllocaInst *Struct = nullptr;
if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
  std::vector<Type *> ArgTypes;
  for (Value *V : StructValues)
    ArgTypes.push_back(V->getType());

  // Allocate a struct at the beginning of this function
  StructArgTy = StructType::get(newFunction->getContext(), ArgTypes);
  Struct = new AllocaInst(StructArgTy, DL.getAllocaAddrSpace(), nullptr,
                          "structArg",
                          &codeReplacer->getParent()->front().front());
  params.push_back(Struct);

  for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
    Value *Idx[2];
    Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
    Idx[1] = ConstantInt::get(Type::getInt32Ty(Context), i);
    GetElementPtrInst *GEP = GetElementPtrInst::Create(
        StructArgTy, Struct, Idx, "gep_" + StructValues[i]->getName());
    codeReplacer->getInstList().push_back(GEP);
    new StoreInst(StructValues[i], GEP, codeReplacer);
  }
}

// Emit the call to the function
call = CallInst::Create(newFunction, params,
                        NumExitBlocks > 1 ? "targetBlock" : "");
// Add debug location to the new call, if the original function has debug
// info. In that case, the terminator of the entry block of the extracted
// function contains the first debug location of the extracted function,
// set in extractCodeRegion.
if (codeReplacer->getParent()->getSubprogram()) {
  if (auto DL = newFunction->getEntryBlock().getTerminator()->getDebugLoc())
    call->setDebugLoc(DL);
}
codeReplacer->getInstList().push_back(call);

// Set swifterror parameter attributes.
for (unsigned SwiftErrArgNo : SwiftErrorArgs) {
  call->addParamAttr(SwiftErrArgNo, Attribute::SwiftError);
  newFunction->addParamAttr(SwiftErrArgNo, Attribute::SwiftError);
}

Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
unsigned FirstOut = inputs.size();
if (!AggregateArgs)
  std::advance(OutputArgBegin, inputs.size());

// Reload the outputs passed in by reference.
for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
  Value *Output = nullptr;
  if (AggregateArgs) {
    Value *Idx[2];
    Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
    Idx[1] = ConstantInt::get(Type::getInt32Ty(Context), FirstOut + i);
    GetElementPtrInst *GEP = GetElementPtrInst::Create(
        StructArgTy, Struct, Idx, "gep_reload_" + outputs[i]->getName());
    codeReplacer->getInstList().push_back(GEP);
    Output = GEP;
  } else {
    Output = ReloadOutputs[i];
  }
  LoadInst *load = new LoadInst(outputs[i]->getType(), Output,
                                outputs[i]->getName() + ".reload",
                                codeReplacer);
  Reloads.push_back(load);
  std::vector<User *> Users(outputs[i]->user_begin(), outputs[i]->user_end());
  for (unsigned u = 0, e = Users.size(); u != e; ++u) {
    Instruction *inst = cast<Instruction>(Users[u]);
    if (!Blocks.count(inst->getParent()))
      inst->replaceUsesOfWith(outputs[i], load);
  }
}

// Now we can emit a switch statement using the call as a value.
SwitchInst *TheSwitch =
    SwitchInst::Create(Constant::getNullValue(Type::getInt16Ty(Context)),
                       codeReplacer, 0, codeReplacer);

// Since there may be multiple exits from the original region, make the new
// function return an unsigned, switch on that number.  This loop iterates
// over all of the blocks in the extracted region, updating any terminator
// instructions in the to-be-extracted region that branch to blocks that are
// not in the region to be extracted.
std::map<BasicBlock *, BasicBlock *> ExitBlockMap;

unsigned switchVal = 0;
for (BasicBlock *Block : Blocks) {
  Instruction *TI = Block->getTerminator();
  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
    if (!Blocks.count(TI->getSuccessor(i))) {
      BasicBlock *OldTarget = TI->getSuccessor(i);
      // add a new basic block which returns the appropriate value
      BasicBlock *&NewTarget = ExitBlockMap[OldTarget];
      if (!NewTarget) {
        // If we don't already have an exit stub for this non-extracted
        // destination, create one now!
        NewTarget = BasicBlock::Create(Context,
                                       OldTarget->getName() + ".exitStub",
                                       newFunction);
        unsigned SuccNum = switchVal++;

        Value *brVal = nullptr;
        switch (NumExitBlocks) {
        case 0:
        case 1: break;  // No value needed.
        case 2:         // Conditional branch, return a bool
          brVal = ConstantInt::get(Type::getInt1Ty(Context), !SuccNum);
          break;
        default:
          brVal = ConstantInt::get(Type::getInt16Ty(Context), SuccNum);
          break;
        }

        ReturnInst::Create(Context, brVal, NewTarget);

        // Update the switch instruction.
        TheSwitch->addCase(ConstantInt::get(Type::getInt16Ty(Context),
                                            SuccNum),
                           OldTarget);
      }

      // rewrite the original branch instruction with this new target
      TI->setSuccessor(i, NewTarget);
    }
}

// Store the arguments right after the definition of output value.
// This should be proceeded after creating exit stubs to be ensure that invoke
// result restore will be placed in the outlined function.
Function::arg_iterator OAI = OutputArgBegin;
for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
  auto *OutI = dyn_cast<Instruction>(outputs[i]);
  if (!OutI)
    continue;

  // Find proper insertion point.
  BasicBlock::iterator InsertPt;
  // In case OutI is an invoke, we insert the store at the beginning in the
  // 'normal destination' BB. Otherwise we insert the store right after OutI.
  if (auto *InvokeI = dyn_cast<InvokeInst>(OutI))
    InsertPt = InvokeI->getNormalDest()->getFirstInsertionPt();
  else if (auto *Phi = dyn_cast<PHINode>(OutI))
    InsertPt = Phi->getParent()->getFirstInsertionPt();
  else
    InsertPt = std::next(OutI->getIterator());

  Instruction *InsertBefore = &*InsertPt;
  assert((InsertBefore->getFunction() == newFunction ||(((InsertBefore->getFunction() == newFunction || Blocks.count
(InsertBefore->getParent())) && "InsertPt should be in new function"
) ? static_cast<void> (0) : __assert_fail ("(InsertBefore->getFunction() == newFunction || Blocks.count(InsertBefore->getParent())) && \"InsertPt should be in new function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1310, __PRETTY_FUNCTION__))
          Blocks.count(InsertBefore->getParent())) &&(((InsertBefore->getFunction() == newFunction || Blocks.count
(InsertBefore->getParent())) && "InsertPt should be in new function"
) ? static_cast<void> (0) : __assert_fail ("(InsertBefore->getFunction() == newFunction || Blocks.count(InsertBefore->getParent())) && \"InsertPt should be in new function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1310, __PRETTY_FUNCTION__))
         "InsertPt should be in new function")(((InsertBefore->getFunction() == newFunction || Blocks.count
(InsertBefore->getParent())) && "InsertPt should be in new function"
) ? static_cast<void> (0) : __assert_fail ("(InsertBefore->getFunction() == newFunction || Blocks.count(InsertBefore->getParent())) && \"InsertPt should be in new function\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1310, __PRETTY_FUNCTION__));
  assert(OAI != newFunction->arg_end() &&((OAI != newFunction->arg_end() && "Number of output arguments should match "
 "the amount of defined values") ? static_cast<void> (0
) : __assert_fail ("OAI != newFunction->arg_end() && \"Number of output arguments should match \" \"the amount of defined values\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1313, __PRETTY_FUNCTION__))
         "Number of output arguments should match "((OAI != newFunction->arg_end() && "Number of output arguments should match "
 "the amount of defined values") ? static_cast<void> (0
) : __assert_fail ("OAI != newFunction->arg_end() && \"Number of output arguments should match \" \"the amount of defined values\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1313, __PRETTY_FUNCTION__))
         "the amount of defined values")((OAI != newFunction->arg_end() && "Number of output arguments should match "
 "the amount of defined values") ? static_cast<void> (0
) : __assert_fail ("OAI != newFunction->arg_end() && \"Number of output arguments should match \" \"the amount of defined values\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1313, __PRETTY_FUNCTION__));
  if (AggregateArgs) {
    Value *Idx[2];
    Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
    Idx[1] = ConstantInt::get(Type::getInt32Ty(Context), FirstOut + i);
    GetElementPtrInst *GEP = GetElementPtrInst::Create(
        StructArgTy, &*OAI, Idx, "gep_" + outputs[i]->getName(),
        InsertBefore);
    new StoreInst(outputs[i], GEP, InsertBefore);
    // Since there should be only one struct argument aggregating
    // all the output values, we shouldn't increment OAI, which always
    // points to the struct argument, in this case.
  } else {
    new StoreInst(outputs[i], &*OAI, InsertBefore);
    ++OAI;
  }
}

// Now that we've done the deed, simplify the switch instruction.
Type *OldFnRetTy = TheSwitch->getParent()->getParent()->getReturnType();
switch (NumExitBlocks) {
case 0:
  // There are no successors (the block containing the switch itself), which
  // means that previously this was the last part of the function, and hence
  // this should be rewritten as a `ret'

  // Check if the function should return a value
  if (OldFnRetTy->isVoidTy()) {
    ReturnInst::Create(Context, nullptr, TheSwitch);  // Return void
  } else if (OldFnRetTy == TheSwitch->getCondition()->getType()) {
    // return what we have
    ReturnInst::Create(Context, TheSwitch->getCondition(), TheSwitch);
  } else {
    // Otherwise we must have code extracted an unwind or something, just
    // return whatever we want.
    ReturnInst::Create(Context,
                       Constant::getNullValue(OldFnRetTy), TheSwitch);
  }

  TheSwitch->eraseFromParent();
  break;
case 1:
  // Only a single destination, change the switch into an unconditional
  // branch.
  BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch);
  TheSwitch->eraseFromParent();
  break;
case 2:
  BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch->getSuccessor(2),
                     call, TheSwitch);
  TheSwitch->eraseFromParent();
  break;
default:
  // Otherwise, make the default destination of the switch instruction be one
  // of the other successors.
  TheSwitch->setCondition(call);
  TheSwitch->setDefaultDest(TheSwitch->getSuccessor(NumExitBlocks));
  // Remove redundant case
  TheSwitch->removeCase(SwitchInst::CaseIt(TheSwitch, NumExitBlocks-1));
  break;
}

// Insert lifetime markers around the reloads of any output values. The
// allocas output values are stored in are only in-use in the codeRepl block.
insertLifetimeMarkersSurroundingCall(M, ReloadOutputs, ReloadOutputs, call);

return call;
1380}

1382void CodeExtractor::moveCodeToFunction(Function *newFunction) {
Function *oldFunc = (*Blocks.begin())->getParent();
Function::BasicBlockListType &oldBlocks = oldFunc->getBasicBlockList();
Function::BasicBlockListType &newBlocks = newFunction->getBasicBlockList();

for (BasicBlock *Block : Blocks) {
  // Delete the basic block from the old function, and the list of blocks
  oldBlocks.remove(Block);

  // Insert this basic block into the new function
  newBlocks.push_back(Block);
}
1394}

1396void CodeExtractor::calculateNewCallTerminatorWeights(
  BasicBlock *CodeReplacer,
  DenseMap<BasicBlock *, BlockFrequency> &ExitWeights,
  BranchProbabilityInfo *BPI) {
using Distribution = BlockFrequencyInfoImplBase::Distribution;
using BlockNode = BlockFrequencyInfoImplBase::BlockNode;

// Update the branch weights for the exit block.
Instruction *TI = CodeReplacer->getTerminator();
SmallVector<unsigned, 8> BranchWeights(TI->getNumSuccessors(), 0);

// Block Frequency distribution with dummy node.
Distribution BranchDist;

SmallVector<BranchProbability, 4> EdgeProbabilities(
    TI->getNumSuccessors(), BranchProbability::getUnknown());

// Add each of the frequencies of the successors.
for (unsigned i = 0, e = TI->getNumSuccessors(); i < e; ++i) {
  BlockNode ExitNode(i);
  uint64_t ExitFreq = ExitWeights[TI->getSuccessor(i)].getFrequency();
  if (ExitFreq != 0)
    BranchDist.addExit(ExitNode, ExitFreq);
  else
    EdgeProbabilities[i] = BranchProbability::getZero();
}

// Check for no total weight.
if (BranchDist.Total == 0) {
  BPI->setEdgeProbability(CodeReplacer, EdgeProbabilities);
  return;
}

// Normalize the distribution so that they can fit in unsigned.
BranchDist.normalize();

// Create normalized branch weights and set the metadata.
for (unsigned I = 0, E = BranchDist.Weights.size(); I < E; ++I) {
  const auto &Weight = BranchDist.Weights[I];

  // Get the weight and update the current BFI.
  BranchWeights[Weight.TargetNode.Index] = Weight.Amount;
  BranchProbability BP(Weight.Amount, BranchDist.Total);
  EdgeProbabilities[Weight.TargetNode.Index] = BP;
}
BPI->setEdgeProbability(CodeReplacer, EdgeProbabilities);
TI->setMetadata(
    LLVMContext::MD_prof,
    MDBuilder(TI->getContext()).createBranchWeights(BranchWeights));
1445}

1447/// Erase debug info intrinsics which refer to values in \p F but aren't in
1448/// \p F.
1449static void eraseDebugIntrinsicsWithNonLocalRefs(Function &F) {
for (Instruction &I : instructions(F)) {
  SmallVector<DbgVariableIntrinsic *, 4> DbgUsers;
  findDbgUsers(DbgUsers, &I);
  for (DbgVariableIntrinsic *DVI : DbgUsers)
    if (DVI->getFunction() != &F)
      DVI->eraseFromParent();
}
1457}

1459/// Fix up the debug info in the old and new functions by pointing line
1460/// locations and debug intrinsics to the new subprogram scope, and by deleting
1461/// intrinsics which point to values outside of the new function.
1462static void fixupDebugInfoPostExtraction(Function &OldFunc, Function &NewFunc,
                                       CallInst &TheCall) {
DISubprogram *OldSP = OldFunc.getSubprogram();
LLVMContext &Ctx = OldFunc.getContext();

if (!OldSP) {
  // Erase any debug info the new function contains.
  stripDebugInfo(NewFunc);
  // Make sure the old function doesn't contain any non-local metadata refs.
  eraseDebugIntrinsicsWithNonLocalRefs(NewFunc);
  return;
}

// Create a subprogram for the new function. Leave out a description of the
// function arguments, as the parameters don't correspond to anything at the
// source level.
assert(OldSP->getUnit() && "Missing compile unit for subprogram")((OldSP->getUnit() && "Missing compile unit for subprogram"
) ? static_cast<void> (0) : __assert_fail ("OldSP->getUnit() && \"Missing compile unit for subprogram\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1478, __PRETTY_FUNCTION__));
DIBuilder DIB(*OldFunc.getParent(), /*AllowUnresolved=*/false,
              OldSP->getUnit());
auto SPType = DIB.createSubroutineType(DIB.getOrCreateTypeArray(None));
DISubprogram::DISPFlags SPFlags = DISubprogram::SPFlagDefinition |
                                  DISubprogram::SPFlagOptimized |
                                  DISubprogram::SPFlagLocalToUnit;
auto NewSP = DIB.createFunction(
    OldSP->getUnit(), NewFunc.getName(), NewFunc.getName(), OldSP->getFile(),
    /*LineNo=*/0, SPType, /*ScopeLine=*/0, DINode::FlagZero, SPFlags);
NewFunc.setSubprogram(NewSP);

// Debug intrinsics in the new function need to be updated in one of two
// ways:
//  1) They need to be deleted, because they describe a value in the old
//     function.
//  2) They need to point to fresh metadata, e.g. because they currently
//     point to a variable in the wrong scope.
SmallDenseMap<DINode *, DINode *> RemappedMetadata;
SmallVector<Instruction *, 4> DebugIntrinsicsToDelete;
for (Instruction &I : instructions(NewFunc)) {
  auto *DII = dyn_cast<DbgInfoIntrinsic>(&I);
  if (!DII)
    continue;

  // Point the intrinsic to a fresh label within the new function.
  if (auto *DLI = dyn_cast<DbgLabelInst>(&I)) {
    DILabel *OldLabel = DLI->getLabel();
    DINode *&NewLabel = RemappedMetadata[OldLabel];
    if (!NewLabel)
      NewLabel = DILabel::get(Ctx, NewSP, OldLabel->getName(),
                              OldLabel->getFile(), OldLabel->getLine());
    DLI->setArgOperand(0, MetadataAsValue::get(Ctx, NewLabel));
    continue;
  }

  auto IsInvalidLocation = [&NewFunc](Value *Location) {
    // Location is invalid if it isn't a constant or an instruction, or is an
    // instruction but isn't in the new function.
    if (!Location ||
        (!isa<Constant>(Location) && !isa<Instruction>(Location)))
      return true;
    Instruction *LocationInst = dyn_cast<Instruction>(Location);
    return LocationInst && LocationInst->getFunction() != &NewFunc;
  };

  auto *DVI = cast<DbgVariableIntrinsic>(DII);
  // If any of the used locations are invalid, delete the intrinsic.
  if (any_of(DVI->location_ops(), IsInvalidLocation)) {
    DebugIntrinsicsToDelete.push_back(DVI);
    continue;
  }

  // Point the intrinsic to a fresh variable within the new function.
  DILocalVariable *OldVar = DVI->getVariable();
  DINode *&NewVar = RemappedMetadata[OldVar];
  if (!NewVar)
    NewVar = DIB.createAutoVariable(
        NewSP, OldVar->getName(), OldVar->getFile(), OldVar->getLine(),
        OldVar->getType(), /*AlwaysPreserve=*/false, DINode::FlagZero,
        OldVar->getAlignInBits());
  DVI->setVariable(cast<DILocalVariable>(NewVar));
}
for (auto *DII : DebugIntrinsicsToDelete)
  DII->eraseFromParent();
DIB.finalizeSubprogram(NewSP);

// Fix up the scope information attached to the line locations in the new
// function.
for (Instruction &I : instructions(NewFunc)) {
  if (const DebugLoc &DL = I.getDebugLoc())
    I.setDebugLoc(DILocation::get(Ctx, DL.getLine(), DL.getCol(), NewSP));

  // Loop info metadata may contain line locations. Fix them up.
  auto updateLoopInfoLoc = [&Ctx,
                            NewSP](const DILocation &Loc) -> DILocation * {
    return DILocation::get(Ctx, Loc.getLine(), Loc.getColumn(), NewSP,
                           nullptr);
  };
  updateLoopMetadataDebugLocations(I, updateLoopInfoLoc);
}
if (!TheCall.getDebugLoc())
  TheCall.setDebugLoc(DILocation::get(Ctx, 0, 0, OldSP));

eraseDebugIntrinsicsWithNonLocalRefs(NewFunc);
1563}

1565Function *
1566CodeExtractor::extractCodeRegion(const CodeExtractorAnalysisCache &CEAC) {
if (!isEligible())
  return nullptr;

// Assumption: this is a single-entry code region, and the header is the first
// block in the region.
BasicBlock *header = *Blocks.begin();
Function *oldFunction = header->getParent();

// Calculate the entry frequency of the new function before we change the root
//   block.
BlockFrequency EntryFreq;
if (BFI) {
  assert(BPI && "Both BPI and BFI are required to preserve profile info")((BPI && "Both BPI and BFI are required to preserve profile info"
) ? static_cast<void> (0) : __assert_fail ("BPI && \"Both BPI and BFI are required to preserve profile info\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1579, __PRETTY_FUNCTION__));
  for (BasicBlock *Pred : predecessors(header)) {
    if (Blocks.count(Pred))
      continue;
    EntryFreq +=
        BFI->getBlockFreq(Pred) * BPI->getEdgeProbability(Pred, header);
  }
}

// Remove @llvm.assume calls that will be moved to the new function from the
// old function's assumption cache.
for (BasicBlock *Block : Blocks) {
  for (auto It = Block->begin(), End = Block->end(); It != End;) {
    Instruction *I = &*It;
    ++It;

    if (match(I, m_Intrinsic<Intrinsic::assume>())) {
      if (AC)
        AC->unregisterAssumption(cast<CallInst>(I));
      I->eraseFromParent();
    }
  }
}

// If we have any return instructions in the region, split those blocks so
// that the return is not in the region.
splitReturnBlocks();

// Calculate the exit blocks for the extracted region and the total exit
// weights for each of those blocks.
DenseMap<BasicBlock *, BlockFrequency> ExitWeights;
SmallPtrSet<BasicBlock *, 1> ExitBlocks;
for (BasicBlock *Block : Blocks) {
  for (BasicBlock *Succ : successors(Block)) {
    if (!Blocks.count(Succ)) {
      // Update the branch weight for this successor.
      if (BFI) {
        BlockFrequency &BF = ExitWeights[Succ];
        BF += BFI->getBlockFreq(Block) * BPI->getEdgeProbability(Block, Succ);
      }
      ExitBlocks.insert(Succ);
    }
  }
}
NumExitBlocks = ExitBlocks.size();

// If we have to split PHI nodes of the entry or exit blocks, do so now.
severSplitPHINodesOfEntry(header);
severSplitPHINodesOfExits(ExitBlocks);

// This takes place of the original loop
BasicBlock *codeReplacer = BasicBlock::Create(header->getContext(),
                                              "codeRepl", oldFunction,
                                              header);

// The new function needs a root node because other nodes can branch to the
// head of the region, but the entry node of a function cannot have preds.
BasicBlock *newFuncRoot = BasicBlock::Create(header->getContext(),
                                             "newFuncRoot");
auto *BranchI = BranchInst::Create(header);
// If the original function has debug info, we have to add a debug location
// to the new branch instruction from the artificial entry block.
// We use the debug location of the first instruction in the extracted
// blocks, as there is no other equivalent line in the source code.
if (oldFunction->getSubprogram()) {
  any_of(Blocks, [&BranchI](const BasicBlock *BB) {
    return any_of(*BB, [&BranchI](const Instruction &I) {
      if (!I.getDebugLoc())
        return false;
      BranchI->setDebugLoc(I.getDebugLoc());
      return true;
    });
  });
}
newFuncRoot->getInstList().push_back(BranchI);

ValueSet inputs, outputs, SinkingCands, HoistingCands;
BasicBlock *CommonExit = nullptr;
findAllocas(CEAC, SinkingCands, HoistingCands, CommonExit);
assert(HoistingCands.empty() || CommonExit)((HoistingCands.empty() || CommonExit) ? static_cast<void>
 (0) : __assert_fail ("HoistingCands.empty() || CommonExit", "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1658, __PRETTY_FUNCTION__));

// Find inputs to, outputs from the code region.
findInputsOutputs(inputs, outputs, SinkingCands);

// Now sink all instructions which only have non-phi uses inside the region.
// Group the allocas at the start of the block, so that any bitcast uses of
// the allocas are well-defined.
AllocaInst *FirstSunkAlloca = nullptr;
for (auto *II : SinkingCands) {
  if (auto *AI = dyn_cast<AllocaInst>(II)) {
    AI->moveBefore(*newFuncRoot, newFuncRoot->getFirstInsertionPt());
    if (!FirstSunkAlloca)
      FirstSunkAlloca = AI;
  }
}
assert((SinkingCands.empty() || FirstSunkAlloca) &&(((SinkingCands.empty() || FirstSunkAlloca) && "Did not expect a sink candidate without any allocas"
) ? static_cast<void> (0) : __assert_fail ("(SinkingCands.empty() || FirstSunkAlloca) && \"Did not expect a sink candidate without any allocas\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1675, __PRETTY_FUNCTION__))
       "Did not expect a sink candidate without any allocas")(((SinkingCands.empty() || FirstSunkAlloca) && "Did not expect a sink candidate without any allocas"
) ? static_cast<void> (0) : __assert_fail ("(SinkingCands.empty() || FirstSunkAlloca) && \"Did not expect a sink candidate without any allocas\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1675, __PRETTY_FUNCTION__));
for (auto *II : SinkingCands) {
  if (!isa<AllocaInst>(II)) {
    cast<Instruction>(II)->moveAfter(FirstSunkAlloca);
  }
}

if (!HoistingCands.empty()) {
  auto *HoistToBlock = findOrCreateBlockForHoisting(CommonExit);
  Instruction *TI = HoistToBlock->getTerminator();
  for (auto *II : HoistingCands)
    cast<Instruction>(II)->moveBefore(TI);
}

// Collect objects which are inputs to the extraction region and also
// referenced by lifetime start markers within it. The effects of these
// markers must be replicated in the calling function to prevent the stack
// coloring pass from merging slots which store input objects.
ValueSet LifetimesStart;
eraseLifetimeMarkersOnInputs(Blocks, SinkingCands, LifetimesStart);

// Construct new function based on inputs/outputs & add allocas for all defs.
Function *newFunction =
    constructFunction(inputs, outputs, header, newFuncRoot, codeReplacer,
                      oldFunction, oldFunction->getParent());

// Update the entry count of the function.
if (BFI) {
  auto Count = BFI->getProfileCountFromFreq(EntryFreq.getFrequency());
  if (Count.hasValue())
    newFunction->setEntryCount(
        ProfileCount(Count.getValue(), Function::PCT_Real)); // FIXME
  BFI->setBlockFreq(codeReplacer, EntryFreq.getFrequency());
}

CallInst *TheCall =
    emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs);

moveCodeToFunction(newFunction);

// Replicate the effects of any lifetime start/end markers which referenced
// input objects in the extraction region by placing markers around the call.
insertLifetimeMarkersSurroundingCall(
    oldFunction->getParent(), LifetimesStart.getArrayRef(), {}, TheCall);

// Propagate personality info to the new function if there is one.
if (oldFunction->hasPersonalityFn())
  newFunction->setPersonalityFn(oldFunction->getPersonalityFn());

// Update the branch weights for the exit block.
if (BFI && NumExitBlocks > 1)
  calculateNewCallTerminatorWeights(codeReplacer, ExitWeights, BPI);

// Loop over all of the PHI nodes in the header and exit blocks, and change
// any references to the old incoming edge to be the new incoming edge.
for (BasicBlock::iterator I = header->begin(); isa<PHINode>(I); ++I) {
  PHINode *PN = cast<PHINode>(I);
  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
    if (!Blocks.count(PN->getIncomingBlock(i)))
      PN->setIncomingBlock(i, newFuncRoot);
}

for (BasicBlock *ExitBB : ExitBlocks)
  for (PHINode &PN : ExitBB->phis()) {
    Value *IncomingCodeReplacerVal = nullptr;
    for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
      // Ignore incoming values from outside of the extracted region.
      if (!Blocks.count(PN.getIncomingBlock(i)))
        continue;

      // Ensure that there is only one incoming value from codeReplacer.
      if (!IncomingCodeReplacerVal) {
        PN.setIncomingBlock(i, codeReplacer);
        IncomingCodeReplacerVal = PN.getIncomingValue(i);
      } else
        assert(IncomingCodeReplacerVal == PN.getIncomingValue(i) &&((IncomingCodeReplacerVal == PN.getIncomingValue(i) &&
 "PHI has two incompatbile incoming values from codeRepl") ? static_cast
<void> (0) : __assert_fail ("IncomingCodeReplacerVal == PN.getIncomingValue(i) && \"PHI has two incompatbile incoming values from codeRepl\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1751, __PRETTY_FUNCTION__))
               "PHI has two incompatbile incoming values from codeRepl")((IncomingCodeReplacerVal == PN.getIncomingValue(i) &&
 "PHI has two incompatbile incoming values from codeRepl") ? static_cast
<void> (0) : __assert_fail ("IncomingCodeReplacerVal == PN.getIncomingValue(i) && \"PHI has two incompatbile incoming values from codeRepl\""
, "/build/llvm-toolchain-snapshot-13~++20210314100619+a28facba1ccd/llvm/lib/Transforms/Utils/CodeExtractor.cpp"
, 1751, __PRETTY_FUNCTION__));
    }
  }

fixupDebugInfoPostExtraction(*oldFunction, *newFunction, *TheCall);

// Mark the new function `noreturn` if applicable. Terminators which resume
// exception propagation are treated as returning instructions. This is to
// avoid inserting traps after calls to outlined functions which unwind.
bool doesNotReturn = none_of(*newFunction, [](const BasicBlock &BB) {
  const Instruction *Term = BB.getTerminator();
  return isa<ReturnInst>(Term) || isa<ResumeInst>(Term);
});
if (doesNotReturn)
  newFunction->setDoesNotReturn();

LLVM_DEBUG(if (verifyFunction(*newFunction, &errs())) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*newFunction, &errs
())) { newFunction->dump(); report_fatal_error("verification of newFunction failed!"
); }; } } while (false)
  newFunction->dump();do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*newFunction, &errs
())) { newFunction->dump(); report_fatal_error("verification of newFunction failed!"
); }; } } while (false)
  report_fatal_error("verification of newFunction failed!");do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*newFunction, &errs
())) { newFunction->dump(); report_fatal_error("verification of newFunction failed!"
); }; } } while (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*newFunction, &errs
())) { newFunction->dump(); report_fatal_error("verification of newFunction failed!"
); }; } } while (false);
LLVM_DEBUG(if (verifyFunction(*oldFunction))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*oldFunction)) report_fatal_error
("verification of oldFunction failed!"); } } while (false)
           report_fatal_error("verification of oldFunction failed!"))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (verifyFunction(*oldFunction)) report_fatal_error
("verification of oldFunction failed!"); } } while (false);
LLVM_DEBUG(if (AC && verifyAssumptionCache(*oldFunction, *newFunction, AC))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (AC && verifyAssumptionCache
(*oldFunction, *newFunction, AC)) report_fatal_error("Stale Asumption cache for old Function!"
); } } while (false)
               report_fatal_error("Stale Asumption cache for old Function!"))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("code-extractor")) { if (AC && verifyAssumptionCache
(*oldFunction, *newFunction, AC)) report_fatal_error("Stale Asumption cache for old Function!"
); } } while (false);
return newFunction;
1776}

1778bool CodeExtractor::verifyAssumptionCache(const Function &OldFunc,
                                        const Function &NewFunc,
                                        AssumptionCache *AC) {
for (auto AssumeVH : AC->assumptions()) {
  auto *I = dyn_cast_or_null<CallInst>(AssumeVH);
  if (!I)
    continue;

  // There shouldn't be any llvm.assume intrinsics in the new function.
  if (I->getFunction() != &OldFunc)
    return true;

  // There shouldn't be any stale affected values in the assumption cache
  // that were previously in the old function, but that have now been moved
  // to the new function.
  for (auto AffectedValVH : AC->assumptionsFor(I->getOperand(0))) {
    auto *AffectedCI = dyn_cast_or_null<CallInst>(AffectedValVH);
    if (!AffectedCI)
      continue;
    if (AffectedCI->getFunction() != &OldFunc)
      return true;
    auto *AssumedInst = cast<Instruction>(AffectedCI->getOperand(0));
    if (AssumedInst->getFunction() != &OldFunc)
      return true;
  }
}
return false;
1805}