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swiftshader/SwiftShader/b8f1a3a/./third_party/llvm-10.0/llvm/lib/Transforms/Utils/InlineFunction.cpp
blob: 6da612eb4e658e3a0239f2898af9355dfda08134 [file]
//===- InlineFunction.cpp - Code to perform function inlining -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements inlining of a function into a call site, resolving
// parameters and the return value as appropriate.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <limits>
#include <string>
#include <utility>
#include <vector>
using namespace llvm;
using ProfileCount = Function::ProfileCount;
static cl::opt<bool>
EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(true),
cl::Hidden,
cl::desc("Convert noalias attributes to metadata during inlining."));
static cl::opt<bool>
PreserveAlignmentAssumptions("preserve-alignment-assumptions-during-inlining",
cl::init(true), cl::Hidden,
cl::desc("Convert align attributes to assumptions during inlining."));
llvm::InlineResult llvm::InlineFunction(CallBase *CB, InlineFunctionInfo &IFI,
AAResults *CalleeAAR,
bool InsertLifetime) {
return InlineFunction(CallSite(CB), IFI, CalleeAAR, InsertLifetime);
}
namespace {
/// A class for recording information about inlining a landing pad.
class LandingPadInliningInfo {
/// Destination of the invoke's unwind.
BasicBlock *OuterResumeDest;
/// Destination for the callee's resume.
BasicBlock *InnerResumeDest = nullptr;
/// LandingPadInst associated with the invoke.
LandingPadInst *CallerLPad = nullptr;
/// PHI for EH values from landingpad insts.
PHINode *InnerEHValuesPHI = nullptr;
SmallVector<Value*, 8> UnwindDestPHIValues;
public:
LandingPadInliningInfo(InvokeInst *II)
: OuterResumeDest(II->getUnwindDest()) {
// If there are PHI nodes in the unwind destination block, we need to keep
// track of which values came into them from the invoke before removing
// the edge from this block.
BasicBlock *InvokeBB = II->getParent();
BasicBlock::iterator I = OuterResumeDest->begin();
for (; isa<PHINode>(I); ++I) {
// Save the value to use for this edge.
PHINode *PHI = cast<PHINode>(I);
UnwindDestPHIValues.push_back(PHI->getIncomingValueForBlock(InvokeBB));
}
CallerLPad = cast<LandingPadInst>(I);
}
/// The outer unwind destination is the target of
/// unwind edges introduced for calls within the inlined function.
BasicBlock *getOuterResumeDest() const {
return OuterResumeDest;
}
BasicBlock *getInnerResumeDest();
LandingPadInst *getLandingPadInst() const { return CallerLPad; }
/// Forward the 'resume' instruction to the caller's landing pad block.
/// When the landing pad block has only one predecessor, this is
/// a simple branch. When there is more than one predecessor, we need to
/// split the landing pad block after the landingpad instruction and jump
/// to there.
void forwardResume(ResumeInst *RI,
SmallPtrSetImpl<LandingPadInst*> &InlinedLPads);
/// Add incoming-PHI values to the unwind destination block for the given
/// basic block, using the values for the original invoke's source block.
void addIncomingPHIValuesFor(BasicBlock *BB) const {
addIncomingPHIValuesForInto(BB, OuterResumeDest);
}
void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
BasicBlock::iterator I = dest->begin();
for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
PHINode *phi = cast<PHINode>(I);
phi->addIncoming(UnwindDestPHIValues[i], src);
}
}
};
} // end anonymous namespace
/// Get or create a target for the branch from ResumeInsts.
BasicBlock *LandingPadInliningInfo::getInnerResumeDest() {
if (InnerResumeDest) return InnerResumeDest;
// Split the landing pad.
BasicBlock::iterator SplitPoint = ++CallerLPad->getIterator();
InnerResumeDest =
OuterResumeDest->splitBasicBlock(SplitPoint,
OuterResumeDest->getName() + ".body");
// The number of incoming edges we expect to the inner landing pad.
const unsigned PHICapacity = 2;
// Create corresponding new PHIs for all the PHIs in the outer landing pad.
Instruction *InsertPoint = &InnerResumeDest->front();
BasicBlock::iterator I = OuterResumeDest->begin();
for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
PHINode *OuterPHI = cast<PHINode>(I);
PHINode *InnerPHI = PHINode::Create(OuterPHI->getType(), PHICapacity,
OuterPHI->getName() + ".lpad-body",
InsertPoint);
OuterPHI->replaceAllUsesWith(InnerPHI);
InnerPHI->addIncoming(OuterPHI, OuterResumeDest);
}
// Create a PHI for the exception values.
InnerEHValuesPHI = PHINode::Create(CallerLPad->getType(), PHICapacity,
"eh.lpad-body", InsertPoint);
CallerLPad->replaceAllUsesWith(InnerEHValuesPHI);
InnerEHValuesPHI->addIncoming(CallerLPad, OuterResumeDest);
// All done.
return InnerResumeDest;
}
/// Forward the 'resume' instruction to the caller's landing pad block.
/// When the landing pad block has only one predecessor, this is a simple
/// branch. When there is more than one predecessor, we need to split the
/// landing pad block after the landingpad instruction and jump to there.
void LandingPadInliningInfo::forwardResume(
ResumeInst *RI, SmallPtrSetImpl<LandingPadInst *> &InlinedLPads) {
BasicBlock *Dest = getInnerResumeDest();
BasicBlock *Src = RI->getParent();
BranchInst::Create(Dest, Src);
// Update the PHIs in the destination. They were inserted in an order which
// makes this work.
addIncomingPHIValuesForInto(Src, Dest);
InnerEHValuesPHI->addIncoming(RI->getOperand(0), Src);
RI->eraseFromParent();
}
/// Helper for getUnwindDestToken/getUnwindDestTokenHelper.
static Value *getParentPad(Value *EHPad) {
if (auto *FPI = dyn_cast<FuncletPadInst>(EHPad))
return FPI->getParentPad();
return cast<CatchSwitchInst>(EHPad)->getParentPad();
}
using UnwindDestMemoTy = DenseMap<Instruction *, Value *>;
/// Helper for getUnwindDestToken that does the descendant-ward part of
/// the search.
static Value *getUnwindDestTokenHelper(Instruction *EHPad,
UnwindDestMemoTy &MemoMap) {
SmallVector<Instruction *, 8> Worklist(1, EHPad);
while (!Worklist.empty()) {
Instruction *CurrentPad = Worklist.pop_back_val();
// We only put pads on the worklist that aren't in the MemoMap. When
// we find an unwind dest for a pad we may update its ancestors, but
// the queue only ever contains uncles/great-uncles/etc. of CurrentPad,
// so they should never get updated while queued on the worklist.
assert(!MemoMap.count(CurrentPad));
Value *UnwindDestToken = nullptr;
if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(CurrentPad)) {
if (CatchSwitch->hasUnwindDest()) {
UnwindDestToken = CatchSwitch->getUnwindDest()->getFirstNonPHI();
} else {
// Catchswitch doesn't have a 'nounwind' variant, and one might be
// annotated as "unwinds to caller" when really it's nounwind (see
// e.g. SimplifyCFGOpt::SimplifyUnreachable), so we can't infer the
// parent's unwind dest from this. We can check its catchpads'
// descendants, since they might include a cleanuppad with an
// "unwinds to caller" cleanupret, which can be trusted.
for (auto HI = CatchSwitch->handler_begin(),
HE = CatchSwitch->handler_end();
HI != HE && !UnwindDestToken; ++HI) {
BasicBlock *HandlerBlock = *HI;
auto *CatchPad = cast<CatchPadInst>(HandlerBlock->getFirstNonPHI());
for (User *Child : CatchPad->users()) {
// Intentionally ignore invokes here -- since the catchswitch is
// marked "unwind to caller", it would be a verifier error if it
// contained an invoke which unwinds out of it, so any invoke we'd
// encounter must unwind to some child of the catch.
if (!isa<CleanupPadInst>(Child) && !isa<CatchSwitchInst>(Child))
continue;
Instruction *ChildPad = cast<Instruction>(Child);
auto Memo = MemoMap.find(ChildPad);
if (Memo == MemoMap.end()) {
// Haven't figured out this child pad yet; queue it.
Worklist.push_back(ChildPad);
continue;
}
// We've already checked this child, but might have found that
// it offers no proof either way.
Value *ChildUnwindDestToken = Memo->second;
if (!ChildUnwindDestToken)
continue;
// We already know the child's unwind dest, which can either
// be ConstantTokenNone to indicate unwind to caller, or can
// be another child of the catchpad. Only the former indicates
// the unwind dest of the catchswitch.
if (isa<ConstantTokenNone>(ChildUnwindDestToken)) {
UnwindDestToken = ChildUnwindDestToken;
break;
}
assert(getParentPad(ChildUnwindDestToken) == CatchPad);
}
}
}
} else {
auto *CleanupPad = cast<CleanupPadInst>(CurrentPad);
for (User *U : CleanupPad->users()) {
if (auto *CleanupRet = dyn_cast<CleanupReturnInst>(U)) {
if (BasicBlock *RetUnwindDest = CleanupRet->getUnwindDest())
UnwindDestToken = RetUnwindDest->getFirstNonPHI();
else
UnwindDestToken = ConstantTokenNone::get(CleanupPad->getContext());
break;
}
Value *ChildUnwindDestToken;
if (auto *Invoke = dyn_cast<InvokeInst>(U)) {
ChildUnwindDestToken = Invoke->getUnwindDest()->getFirstNonPHI();
} else if (isa<CleanupPadInst>(U) || isa<CatchSwitchInst>(U)) {
Instruction *ChildPad = cast<Instruction>(U);
auto Memo = MemoMap.find(ChildPad);
if (Memo == MemoMap.end()) {
// Haven't resolved this child yet; queue it and keep searching.
Worklist.push_back(ChildPad);
continue;
}
// We've checked this child, but still need to ignore it if it
// had no proof either way.
ChildUnwindDestToken = Memo->second;
if (!ChildUnwindDestToken)
continue;
} else {
// Not a relevant user of the cleanuppad
continue;
}
// In a well-formed program, the child/invoke must either unwind to
// an(other) child of the cleanup, or exit the cleanup. In the
// first case, continue searching.
if (isa<Instruction>(ChildUnwindDestToken) &&
getParentPad(ChildUnwindDestToken) == CleanupPad)
continue;
UnwindDestToken = ChildUnwindDestToken;
break;
}
}
// If we haven't found an unwind dest for CurrentPad, we may have queued its
// children, so move on to the next in the worklist.
if (!UnwindDestToken)
continue;
// Now we know that CurrentPad unwinds to UnwindDestToken. It also exits
// any ancestors of CurrentPad up to but not including UnwindDestToken's
// parent pad. Record this in the memo map, and check to see if the
// original EHPad being queried is one of the ones exited.
Value *UnwindParent;
if (auto *UnwindPad = dyn_cast<Instruction>(UnwindDestToken))
UnwindParent = getParentPad(UnwindPad);
else
UnwindParent = nullptr;
bool ExitedOriginalPad = false;
for (Instruction *ExitedPad = CurrentPad;
ExitedPad && ExitedPad != UnwindParent;
ExitedPad = dyn_cast<Instruction>(getParentPad(ExitedPad))) {
// Skip over catchpads since they just follow their catchswitches.
if (isa<CatchPadInst>(ExitedPad))
continue;
MemoMap[ExitedPad] = UnwindDestToken;
ExitedOriginalPad |= (ExitedPad == EHPad);
}
if (ExitedOriginalPad)
return UnwindDestToken;
// Continue the search.
}
// No definitive information is contained within this funclet.
return nullptr;
}
/// Given an EH pad, find where it unwinds. If it unwinds to an EH pad,
/// return that pad instruction. If it unwinds to caller, return
/// ConstantTokenNone. If it does not have a definitive unwind destination,
/// return nullptr.
///
/// This routine gets invoked for calls in funclets in inlinees when inlining
/// an invoke. Since many funclets don't have calls inside them, it's queried
/// on-demand rather than building a map of pads to unwind dests up front.
/// Determining a funclet's unwind dest may require recursively searching its
/// descendants, and also ancestors and cousins if the descendants don't provide
/// an answer. Since most funclets will have their unwind dest immediately
/// available as the unwind dest of a catchswitch or cleanupret, this routine
/// searches top-down from the given pad and then up. To avoid worst-case
/// quadratic run-time given that approach, it uses a memo map to avoid
/// re-processing funclet trees. The callers that rewrite the IR as they go
/// take advantage of this, for correctness, by checking/forcing rewritten
/// pads' entries to match the original callee view.
static Value *getUnwindDestToken(Instruction *EHPad,
UnwindDestMemoTy &MemoMap) {
// Catchpads unwind to the same place as their catchswitch;
// redirct any queries on catchpads so the code below can
// deal with just catchswitches and cleanuppads.
if (auto *CPI = dyn_cast<CatchPadInst>(EHPad))
EHPad = CPI->getCatchSwitch();
// Check if we've already determined the unwind dest for this pad.
auto Memo = MemoMap.find(EHPad);
if (Memo != MemoMap.end())
return Memo->second;
// Search EHPad and, if necessary, its descendants.
Value *UnwindDestToken = getUnwindDestTokenHelper(EHPad, MemoMap);
assert((UnwindDestToken == nullptr) != (MemoMap.count(EHPad) != 0));
if (UnwindDestToken)
return UnwindDestToken;
// No information is available for this EHPad from itself or any of its
// descendants. An unwind all the way out to a pad in the caller would
// need also to agree with the unwind dest of the parent funclet, so
// search up the chain to try to find a funclet with information. Put
// null entries in the memo map to avoid re-processing as we go up.
MemoMap[EHPad] = nullptr;
#ifndef NDEBUG
SmallPtrSet<Instruction *, 4> TempMemos;
TempMemos.insert(EHPad);
#endif
Instruction *LastUselessPad = EHPad;
Value *AncestorToken;
for (AncestorToken = getParentPad(EHPad);
auto *AncestorPad = dyn_cast<Instruction>(AncestorToken);
AncestorToken = getParentPad(AncestorToken)) {
// Skip over catchpads since they just follow their catchswitches.
if (isa<CatchPadInst>(AncestorPad))
continue;
// If the MemoMap had an entry mapping AncestorPad to nullptr, since we
// haven't yet called getUnwindDestTokenHelper for AncestorPad in this
// call to getUnwindDestToken, that would mean that AncestorPad had no
// information in itself, its descendants, or its ancestors. If that
// were the case, then we should also have recorded the lack of information
// for the descendant that we're coming from. So assert that we don't
// find a null entry in the MemoMap for AncestorPad.
assert(!MemoMap.count(AncestorPad) || MemoMap[AncestorPad]);
auto AncestorMemo = MemoMap.find(AncestorPad);
if (AncestorMemo == MemoMap.end()) {
UnwindDestToken = getUnwindDestTokenHelper(AncestorPad, MemoMap);
} else {
UnwindDestToken = AncestorMemo->second;
}
if (UnwindDestToken)
break;
LastUselessPad = AncestorPad;
MemoMap[LastUselessPad] = nullptr;
#ifndef NDEBUG
TempMemos.insert(LastUselessPad);
#endif
}
// We know that getUnwindDestTokenHelper was called on LastUselessPad and
// returned nullptr (and likewise for EHPad and any of its ancestors up to
// LastUselessPad), so LastUselessPad has no information from below. Since
// getUnwindDestTokenHelper must investigate all downward paths through
// no-information nodes to prove that a node has no information like this,
// and since any time it finds information it records it in the MemoMap for
// not just the immediately-containing funclet but also any ancestors also
// exited, it must be the case that, walking downward from LastUselessPad,
// visiting just those nodes which have not been mapped to an unwind dest
// by getUnwindDestTokenHelper (the nullptr TempMemos notwithstanding, since
// they are just used to keep getUnwindDestTokenHelper from repeating work),
// any node visited must have been exhaustively searched with no information
// for it found.
SmallVector<Instruction *, 8> Worklist(1, LastUselessPad);
while (!Worklist.empty()) {
Instruction *UselessPad = Worklist.pop_back_val();
auto Memo = MemoMap.find(UselessPad);
if (Memo != MemoMap.end() && Memo->second) {
// Here the name 'UselessPad' is a bit of a misnomer, because we've found
// that it is a funclet that does have information about unwinding to
// a particular destination; its parent was a useless pad.
// Since its parent has no information, the unwind edge must not escape
// the parent, and must target a sibling of this pad. This local unwind
// gives us no information about EHPad. Leave it and the subtree rooted
// at it alone.
assert(getParentPad(Memo->second) == getParentPad(UselessPad));
continue;
}
// We know we don't have information for UselesPad. If it has an entry in
// the MemoMap (mapping it to nullptr), it must be one of the TempMemos
// added on this invocation of getUnwindDestToken; if a previous invocation
// recorded nullptr, it would have had to prove that the ancestors of
// UselessPad, which include LastUselessPad, had no information, and that
// in turn would have required proving that the descendants of
// LastUselesPad, which include EHPad, have no information about
// LastUselessPad, which would imply that EHPad was mapped to nullptr in
// the MemoMap on that invocation, which isn't the case if we got here.
assert(!MemoMap.count(UselessPad) || TempMemos.count(UselessPad));
// Assert as we enumerate users that 'UselessPad' doesn't have any unwind
// information that we'd be contradicting by making a map entry for it
// (which is something that getUnwindDestTokenHelper must have proved for
// us to get here). Just assert on is direct users here; the checks in
// this downward walk at its descendants will verify that they don't have
// any unwind edges that exit 'UselessPad' either (i.e. they either have no
// unwind edges or unwind to a sibling).
MemoMap[UselessPad] = UnwindDestToken;
if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(UselessPad)) {
assert(CatchSwitch->getUnwindDest() == nullptr && "Expected useless pad");
for (BasicBlock *HandlerBlock : CatchSwitch->handlers()) {
auto *CatchPad = HandlerBlock->getFirstNonPHI();
for (User *U : CatchPad->users()) {
assert(
(!isa<InvokeInst>(U) ||
(getParentPad(
cast<InvokeInst>(U)->getUnwindDest()->getFirstNonPHI()) ==
CatchPad)) &&
"Expected useless pad");
if (isa<CatchSwitchInst>(U) || isa<CleanupPadInst>(U))
Worklist.push_back(cast<Instruction>(U));
}
}
} else {
assert(isa<CleanupPadInst>(UselessPad));
for (User *U : UselessPad->users()) {
assert(!isa<CleanupReturnInst>(U) && "Expected useless pad");
assert((!isa<InvokeInst>(U) ||
(getParentPad(
cast<InvokeInst>(U)->getUnwindDest()->getFirstNonPHI()) ==
UselessPad)) &&
"Expected useless pad");
if (isa<CatchSwitchInst>(U) || isa<CleanupPadInst>(U))
Worklist.push_back(cast<Instruction>(U));
}
}
}
return UnwindDestToken;
}
/// When we inline a basic block into an invoke,
/// we have to turn all of the calls that can throw into invokes.
/// This function analyze BB to see if there are any calls, and if so,
/// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
/// nodes in that block with the values specified in InvokeDestPHIValues.
static BasicBlock *HandleCallsInBlockInlinedThroughInvoke(
BasicBlock *BB, BasicBlock *UnwindEdge,
UnwindDestMemoTy *FuncletUnwindMap = nullptr) {
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *I = &*BBI++;
// We only need to check for function calls: inlined invoke
// instructions require no special handling.
CallInst *CI = dyn_cast<CallInst>(I);
if (!CI || CI->doesNotThrow() || isa<InlineAsm>(CI->getCalledValue()))
continue;
// We do not need to (and in fact, cannot) convert possibly throwing calls
// to @llvm.experimental_deoptimize (resp. @llvm.experimental.guard) into
// invokes. The caller's "segment" of the deoptimization continuation
// attached to the newly inlined @llvm.experimental_deoptimize
// (resp. @llvm.experimental.guard) call should contain the exception
// handling logic, if any.
if (auto *F = CI->getCalledFunction())
if (F->getIntrinsicID() == Intrinsic::experimental_deoptimize ||
F->getIntrinsicID() == Intrinsic::experimental_guard)
continue;
if (auto FuncletBundle = CI->getOperandBundle(LLVMContext::OB_funclet)) {
// This call is nested inside a funclet. If that funclet has an unwind
// destination within the inlinee, then unwinding out of this call would
// be UB. Rewriting this call to an invoke which targets the inlined
// invoke's unwind dest would give the call's parent funclet multiple
// unwind destinations, which is something that subsequent EH table
// generation can't handle and that the veirifer rejects. So when we
// see such a call, leave it as a call.
auto *FuncletPad = cast<Instruction>(FuncletBundle->Inputs[0]);
Value *UnwindDestToken =
getUnwindDestToken(FuncletPad, *FuncletUnwindMap);
if (UnwindDestToken && !isa<ConstantTokenNone>(UnwindDestToken))
continue;
#ifndef NDEBUG
Instruction *MemoKey;
if (auto *CatchPad = dyn_cast<CatchPadInst>(FuncletPad))
MemoKey = CatchPad->getCatchSwitch();
else
MemoKey = FuncletPad;
assert(FuncletUnwindMap->count(MemoKey) &&
(*FuncletUnwindMap)[MemoKey] == UnwindDestToken &&
"must get memoized to avoid confusing later searches");
#endif // NDEBUG
}
changeToInvokeAndSplitBasicBlock(CI, UnwindEdge);
return BB;
}
return nullptr;
}
/// If we inlined an invoke site, we need to convert calls
/// in the body of the inlined function into invokes.
///
/// II is the invoke instruction being inlined. FirstNewBlock is the first
/// block of the inlined code (the last block is the end of the function),
/// and InlineCodeInfo is information about the code that got inlined.
static void HandleInlinedLandingPad(InvokeInst *II, BasicBlock *FirstNewBlock,
ClonedCodeInfo &InlinedCodeInfo) {
BasicBlock *InvokeDest = II->getUnwindDest();
Function *Caller = FirstNewBlock->getParent();
// The inlined code is currently at the end of the function, scan from the
// start of the inlined code to its end, checking for stuff we need to
// rewrite.
LandingPadInliningInfo Invoke(II);
// Get all of the inlined landing pad instructions.
SmallPtrSet<LandingPadInst*, 16> InlinedLPads;
for (Function::iterator I = FirstNewBlock->getIterator(), E = Caller->end();
I != E; ++I)
if (InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator()))
InlinedLPads.insert(II->getLandingPadInst());
// Append the clauses from the outer landing pad instruction into the inlined
// landing pad instructions.
LandingPadInst *OuterLPad = Invoke.getLandingPadInst();
for (LandingPadInst *InlinedLPad : InlinedLPads) {
unsigned OuterNum = OuterLPad->getNumClauses();
InlinedLPad->reserveClauses(OuterNum);
for (unsigned OuterIdx = 0; OuterIdx != OuterNum; ++OuterIdx)
InlinedLPad->addClause(OuterLPad->getClause(OuterIdx));
if (OuterLPad->isCleanup())
InlinedLPad->setCleanup(true);
}
for (Function::iterator BB = FirstNewBlock->getIterator(), E = Caller->end();
BB != E; ++BB) {
if (InlinedCodeInfo.ContainsCalls)
if (BasicBlock *NewBB = HandleCallsInBlockInlinedThroughInvoke(
&*BB, Invoke.getOuterResumeDest()))
// Update any PHI nodes in the exceptional block to indicate that there
// is now a new entry in them.
Invoke.addIncomingPHIValuesFor(NewBB);
// Forward any resumes that are remaining here.
if (ResumeInst *RI = dyn_cast<ResumeInst>(BB->getTerminator()))
Invoke.forwardResume(RI, InlinedLPads);
}
// Now that everything is happy, we have one final detail. The PHI nodes in
// the exception destination block still have entries due to the original
// invoke instruction. Eliminate these entries (which might even delete the
// PHI node) now.
InvokeDest->removePredecessor(II->getParent());
}
/// If we inlined an invoke site, we need to convert calls
/// in the body of the inlined function into invokes.
///
/// II is the invoke instruction being inlined. FirstNewBlock is the first
/// block of the inlined code (the last block is the end of the function),
/// and InlineCodeInfo is information about the code that got inlined.
static void HandleInlinedEHPad(InvokeInst *II, BasicBlock *FirstNewBlock,
ClonedCodeInfo &InlinedCodeInfo) {
BasicBlock *UnwindDest = II->getUnwindDest();
Function *Caller = FirstNewBlock->getParent();
assert(UnwindDest->getFirstNonPHI()->isEHPad() && "unexpected BasicBlock!");
// If there are PHI nodes in the unwind destination block, we need to keep
// track of which values came into them from the invoke before removing the
// edge from this block.
SmallVector<Value *, 8> UnwindDestPHIValues;
BasicBlock *InvokeBB = II->getParent();
for (Instruction &I : *UnwindDest) {
// Save the value to use for this edge.
PHINode *PHI = dyn_cast<PHINode>(&I);
if (!PHI)
break;
UnwindDestPHIValues.push_back(PHI->getIncomingValueForBlock(InvokeBB));
}
// Add incoming-PHI values to the unwind destination block for the given basic
// block, using the values for the original invoke's source block.
auto UpdatePHINodes = [&](BasicBlock *Src) {
BasicBlock::iterator I = UnwindDest->begin();
for (Value *V : UnwindDestPHIValues) {
PHINode *PHI = cast<PHINode>(I);
PHI->addIncoming(V, Src);
++I;
}
};
// This connects all the instructions which 'unwind to caller' to the invoke
// destination.
UnwindDestMemoTy FuncletUnwindMap;
for (Function::iterator BB = FirstNewBlock->getIterator(), E = Caller->end();
BB != E; ++BB) {
if (auto *CRI = dyn_cast<CleanupReturnInst>(BB->getTerminator())) {
if (CRI->unwindsToCaller()) {
auto *CleanupPad = CRI->getCleanupPad();
CleanupReturnInst::Create(CleanupPad, UnwindDest, CRI);
CRI->eraseFromParent();
UpdatePHINodes(&*BB);
// Finding a cleanupret with an unwind destination would confuse
// subsequent calls to getUnwindDestToken, so map the cleanuppad
// to short-circuit any such calls and recognize this as an "unwind
// to caller" cleanup.
assert(!FuncletUnwindMap.count(CleanupPad) ||
isa<ConstantTokenNone>(FuncletUnwindMap[CleanupPad]));
FuncletUnwindMap[CleanupPad] =
ConstantTokenNone::get(Caller->getContext());
}
}
Instruction *I = BB->getFirstNonPHI();
if (!I->isEHPad())
continue;
Instruction *Replacement = nullptr;
if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(I)) {
if (CatchSwitch->unwindsToCaller()) {
Value *UnwindDestToken;
if (auto *ParentPad =
dyn_cast<Instruction>(CatchSwitch->getParentPad())) {
// This catchswitch is nested inside another funclet. If that
// funclet has an unwind destination within the inlinee, then
// unwinding out of this catchswitch would be UB. Rewriting this
// catchswitch to unwind to the inlined invoke's unwind dest would
// give the parent funclet multiple unwind destinations, which is
// something that subsequent EH table generation can't handle and
// that the veirifer rejects. So when we see such a call, leave it
// as "unwind to caller".
UnwindDestToken = getUnwindDestToken(ParentPad, FuncletUnwindMap);
if (UnwindDestToken && !isa<ConstantTokenNone>(UnwindDestToken))
continue;
} else {
// This catchswitch has no parent to inherit constraints from, and
// none of its descendants can have an unwind edge that exits it and
// targets another funclet in the inlinee. It may or may not have a
// descendant that definitively has an unwind to caller. In either
// case, we'll have to assume that any unwinds out of it may need to
// be routed to the caller, so treat it as though it has a definitive
// unwind to caller.
UnwindDestToken = ConstantTokenNone::get(Caller->getContext());
}
auto *NewCatchSwitch = CatchSwitchInst::Create(
CatchSwitch->getParentPad(), UnwindDest,
CatchSwitch->getNumHandlers(), CatchSwitch->getName(),
CatchSwitch);
for (BasicBlock *PadBB : CatchSwitch->handlers())
NewCatchSwitch->addHandler(PadBB);
// Propagate info for the old catchswitch over to the new one in
// the unwind map. This also serves to short-circuit any subsequent
// checks for the unwind dest of this catchswitch, which would get
// confused if they found the outer handler in the callee.
FuncletUnwindMap[NewCatchSwitch] = UnwindDestToken;
Replacement = NewCatchSwitch;
}
} else if (!isa<FuncletPadInst>(I)) {
llvm_unreachable("unexpected EHPad!");
}
if (Replacement) {
Replacement->takeName(I);
I->replaceAllUsesWith(Replacement);
I->eraseFromParent();
UpdatePHINodes(&*BB);
}
}
if (InlinedCodeInfo.ContainsCalls)
for (Function::iterator BB = FirstNewBlock->getIterator(),
E = Caller->end();
BB != E; ++BB)
if (BasicBlock *NewBB = HandleCallsInBlockInlinedThroughInvoke(
&*BB, UnwindDest, &FuncletUnwindMap))
// Update any PHI nodes in the exceptional block to indicate that there
// is now a new entry in them.
UpdatePHINodes(NewBB);
// Now that everything is happy, we have one final detail. The PHI nodes in
// the exception destination block still have entries due to the original
// invoke instruction. Eliminate these entries (which might even delete the
// PHI node) now.
UnwindDest->removePredecessor(InvokeBB);
}
/// When inlining a call site that has !llvm.mem.parallel_loop_access or
/// llvm.access.group metadata, that metadata should be propagated to all
/// memory-accessing cloned instructions.
static void PropagateParallelLoopAccessMetadata(CallSite CS,
ValueToValueMapTy &VMap) {
MDNode *M =
CS.getInstruction()->getMetadata(LLVMContext::MD_mem_parallel_loop_access);
MDNode *CallAccessGroup =
CS.getInstruction()->getMetadata(LLVMContext::MD_access_group);
if (!M && !CallAccessGroup)
return;
for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
VMI != VMIE; ++VMI) {
if (!VMI->second)
continue;
Instruction *NI = dyn_cast<Instruction>(VMI->second);
if (!NI)
continue;
if (M) {
if (MDNode *PM =
NI->getMetadata(LLVMContext::MD_mem_parallel_loop_access)) {
M = MDNode::concatenate(PM, M);
NI->setMetadata(LLVMContext::MD_mem_parallel_loop_access, M);
} else if (NI->mayReadOrWriteMemory()) {
NI->setMetadata(LLVMContext::MD_mem_parallel_loop_access, M);
}
}
if (NI->mayReadOrWriteMemory()) {
MDNode *UnitedAccGroups = uniteAccessGroups(
NI->getMetadata(LLVMContext::MD_access_group), CallAccessGroup);
NI->setMetadata(LLVMContext::MD_access_group, UnitedAccGroups);
}
}
}
/// When inlining a function that contains noalias scope metadata,
/// this metadata needs to be cloned so that the inlined blocks
/// have different "unique scopes" at every call site. Were this not done, then
/// aliasing scopes from a function inlined into a caller multiple times could
/// not be differentiated (and this would lead to miscompiles because the
/// non-aliasing property communicated by the metadata could have
/// call-site-specific control dependencies).
static void CloneAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap) {
const Function *CalledFunc = CS.getCalledFunction();
SetVector<const MDNode *> MD;
// Note: We could only clone the metadata if it is already used in the
// caller. I'm omitting that check here because it might confuse
// inter-procedural alias analysis passes. We can revisit this if it becomes
// an efficiency or overhead problem.
for (const BasicBlock &I : *CalledFunc)
for (const Instruction &J : I) {
if (const MDNode *M = J.getMetadata(LLVMContext::MD_alias_scope))
MD.insert(M);
if (const MDNode *M = J.getMetadata(LLVMContext::MD_noalias))
MD.insert(M);
}
if (MD.empty())
return;
// Walk the existing metadata, adding the complete (perhaps cyclic) chain to
// the set.
SmallVector<const Metadata *, 16> Queue(MD.begin(), MD.end());
while (!Queue.empty()) {
const MDNode *M = cast<MDNode>(Queue.pop_back_val());
for (unsigned i = 0, ie = M->getNumOperands(); i != ie; ++i)
if (const MDNode *M1 = dyn_cast<MDNode>(M->getOperand(i)))
if (MD.insert(M1))
Queue.push_back(M1);
}
// Now we have a complete set of all metadata in the chains used to specify
// the noalias scopes and the lists of those scopes.
SmallVector<TempMDTuple, 16> DummyNodes;
DenseMap<const MDNode *, TrackingMDNodeRef> MDMap;
for (const MDNode *I : MD) {
DummyNodes.push_back(MDTuple::getTemporary(CalledFunc->getContext(), None));
MDMap[I].reset(DummyNodes.back().get());
}
// Create new metadata nodes to replace the dummy nodes, replacing old
// metadata references with either a dummy node or an already-created new
// node.
for (const MDNode *I : MD) {
SmallVector<Metadata *, 4> NewOps;
for (unsigned i = 0, ie = I->getNumOperands(); i != ie; ++i) {
const Metadata *V = I->getOperand(i);
if (const MDNode *M = dyn_cast<MDNode>(V))
NewOps.push_back(MDMap[M]);
else
NewOps.push_back(const_cast<Metadata *>(V));
}
MDNode *NewM = MDNode::get(CalledFunc->getContext(), NewOps);
MDTuple *TempM = cast<MDTuple>(MDMap[I]);
assert(TempM->isTemporary() && "Expected temporary node");
TempM->replaceAllUsesWith(NewM);
}
// Now replace the metadata in the new inlined instructions with the
// repacements from the map.
for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
VMI != VMIE; ++VMI) {
if (!VMI->second)
continue;
Instruction *NI = dyn_cast<Instruction>(VMI->second);
if (!NI)
continue;
if (MDNode *M = NI->getMetadata(LLVMContext::MD_alias_scope)) {
MDNode *NewMD = MDMap[M];
// If the call site also had alias scope metadata (a list of scopes to
// which instructions inside it might belong), propagate those scopes to
// the inlined instructions.
if (MDNode *CSM =
CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
NewMD = MDNode::concatenate(NewMD, CSM);
NI->setMetadata(LLVMContext::MD_alias_scope, NewMD);
} else if (NI->mayReadOrWriteMemory()) {
if (MDNode *M =
CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
NI->setMetadata(LLVMContext::MD_alias_scope, M);
}
if (MDNode *M = NI->getMetadata(LLVMContext::MD_noalias)) {
MDNode *NewMD = MDMap[M];
// If the call site also had noalias metadata (a list of scopes with
// which instructions inside it don't alias), propagate those scopes to
// the inlined instructions.
if (MDNode *CSM =
CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
NewMD = MDNode::concatenate(NewMD, CSM);
NI->setMetadata(LLVMContext::MD_noalias, NewMD);
} else if (NI->mayReadOrWriteMemory()) {
if (MDNode *M = CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
NI->setMetadata(LLVMContext::MD_noalias, M);
}
}
}
/// If the inlined function has noalias arguments,
/// then add new alias scopes for each noalias argument, tag the mapped noalias
/// parameters with noalias metadata specifying the new scope, and tag all
/// non-derived loads, stores and memory intrinsics with the new alias scopes.
static void AddAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap,
const DataLayout &DL, AAResults *CalleeAAR) {
if (!EnableNoAliasConversion)
return;
const Function *CalledFunc = CS.getCalledFunction();
SmallVector<const Argument *, 4> NoAliasArgs;
for (const Argument &Arg : CalledFunc->args())
if (Arg.hasNoAliasAttr() && !Arg.use_empty())
NoAliasArgs.push_back(&Arg);
if (NoAliasArgs.empty())
return;
// To do a good job, if a noalias variable is captured, we need to know if
// the capture point dominates the particular use we're considering.
DominatorTree DT;
DT.recalculate(const_cast<Function&>(*CalledFunc));
// noalias indicates that pointer values based on the argument do not alias
// pointer values which are not based on it. So we add a new "scope" for each
// noalias function argument. Accesses using pointers based on that argument
// become part of that alias scope, accesses using pointers not based on that
// argument are tagged as noalias with that scope.
DenseMap<const Argument *, MDNode *> NewScopes;
MDBuilder MDB(CalledFunc->getContext());
// Create a new scope domain for this function.
MDNode *NewDomain =
MDB.createAnonymousAliasScopeDomain(CalledFunc->getName());
for (unsigned i = 0, e = NoAliasArgs.size(); i != e; ++i) {
const Argument *A = NoAliasArgs[i];
std::string Name = CalledFunc->getName();
if (A->hasName()) {
Name += ": %";
Name += A->getName();
} else {
Name += ": argument ";
Name += utostr(i);
}
// Note: We always create a new anonymous root here. This is true regardless
// of the linkage of the callee because the aliasing "scope" is not just a
// property of the callee, but also all control dependencies in the caller.
MDNode *NewScope = MDB.createAnonymousAliasScope(NewDomain, Name);
NewScopes.insert(std::make_pair(A, NewScope));
}
// Iterate over all new instructions in the map; for all memory-access
// instructions, add the alias scope metadata.
for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
VMI != VMIE; ++VMI) {
if (const Instruction *I = dyn_cast<Instruction>(VMI->first)) {
if (!VMI->second)
continue;
Instruction *NI = dyn_cast<Instruction>(VMI->second);
if (!NI)
continue;
bool IsArgMemOnlyCall = false, IsFuncCall = false;
SmallVector<const Value *, 2> PtrArgs;
if (const LoadInst *LI = dyn_cast<LoadInst>(I))
PtrArgs.push_back(LI->getPointerOperand());
else if (const StoreInst *SI = dyn_cast<StoreInst>(I))
PtrArgs.push_back(SI->getPointerOperand());
else if (const VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
PtrArgs.push_back(VAAI->getPointerOperand());
else if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I))
PtrArgs.push_back(CXI->getPointerOperand());
else if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I))
PtrArgs.push_back(RMWI->getPointerOperand());
else if (const auto *Call = dyn_cast<CallBase>(I)) {
// If we know that the call does not access memory, then we'll still
// know that about the inlined clone of this call site, and we don't
// need to add metadata.
if (Call->doesNotAccessMemory())
continue;
IsFuncCall = true;
if (CalleeAAR) {
FunctionModRefBehavior MRB = CalleeAAR->getModRefBehavior(Call);
if (MRB == FMRB_OnlyAccessesArgumentPointees ||
MRB == FMRB_OnlyReadsArgumentPointees)
IsArgMemOnlyCall = true;
}
for (Value *Arg : Call->args()) {
// We need to check the underlying objects of all arguments, not just
// the pointer arguments, because we might be passing pointers as
// integers, etc.
// However, if we know that the call only accesses pointer arguments,
// then we only need to check the pointer arguments.
if (IsArgMemOnlyCall && !Arg->getType()->isPointerTy())
continue;
PtrArgs.push_back(Arg);
}
}
// If we found no pointers, then this instruction is not suitable for
// pairing with an instruction to receive aliasing metadata.
// However, if this is a call, this we might just alias with none of the
// noalias arguments.
if (PtrArgs.empty() && !IsFuncCall)
continue;
// It is possible that there is only one underlying object, but you
// need to go through several PHIs to see it, and thus could be
// repeated in the Objects list.
SmallPtrSet<const Value *, 4> ObjSet;
SmallVector<Metadata *, 4> Scopes, NoAliases;
SmallSetVector<const Argument *, 4> NAPtrArgs;
for (const Value *V : PtrArgs) {
SmallVector<const Value *, 4> Objects;
GetUnderlyingObjects(V, Objects, DL, /* LI = */ nullptr);
for (const Value *O : Objects)
ObjSet.insert(O);
}
// Figure out if we're derived from anything that is not a noalias
// argument.
bool CanDeriveViaCapture = false, UsesAliasingPtr = false;
for (const Value *V : ObjSet) {
// Is this value a constant that cannot be derived from any pointer
// value (we need to exclude constant expressions, for example, that
// are formed from arithmetic on global symbols).
bool IsNonPtrConst = isa<ConstantInt>(V) || isa<ConstantFP>(V) ||
isa<ConstantPointerNull>(V) ||
isa<ConstantDataVector>(V) || isa<UndefValue>(V);
if (IsNonPtrConst)
continue;
// If this is anything other than a noalias argument, then we cannot
// completely describe the aliasing properties using alias.scope
// metadata (and, thus, won't add any).
if (const Argument *A = dyn_cast<Argument>(V)) {
if (!A->hasNoAliasAttr())
UsesAliasingPtr = true;
} else {
UsesAliasingPtr = true;
}
// If this is not some identified function-local object (which cannot
// directly alias a noalias argument), or some other argument (which,
// by definition, also cannot alias a noalias argument), then we could
// alias a noalias argument that has been captured).
if (!isa<Argument>(V) &&
!isIdentifiedFunctionLocal(const_cast<Value*>(V)))
CanDeriveViaCapture = true;
}
// A function call can always get captured noalias pointers (via other
// parameters, globals, etc.).
if (IsFuncCall && !IsArgMemOnlyCall)
CanDeriveViaCapture = true;
// First, we want to figure out all of the sets with which we definitely
// don't alias. Iterate over all noalias set, and add those for which:
// 1. The noalias argument is not in the set of objects from which we
// definitely derive.
// 2. The noalias argument has not yet been captured.
// An arbitrary function that might load pointers could see captured
// noalias arguments via other noalias arguments or globals, and so we
// must always check for prior capture.
for (const Argument *A : NoAliasArgs) {
if (!ObjSet.count(A) && (!CanDeriveViaCapture ||
// It might be tempting to skip the
// PointerMayBeCapturedBefore check if
// A->hasNoCaptureAttr() is true, but this is
// incorrect because nocapture only guarantees
// that no copies outlive the function, not
// that the value cannot be locally captured.
!PointerMayBeCapturedBefore(A,
/* ReturnCaptures */ false,
/* StoreCaptures */ false, I, &DT)))
NoAliases.push_back(NewScopes[A]);
}
if (!NoAliases.empty())
NI->setMetadata(LLVMContext::MD_noalias,
MDNode::concatenate(
NI->getMetadata(LLVMContext::MD_noalias),
MDNode::get(CalledFunc->getContext(), NoAliases)));
// Next, we want to figure out all of the sets to which we might belong.
// We might belong to a set if the noalias argument is in the set of
// underlying objects. If there is some non-noalias argument in our list
// of underlying objects, then we cannot add a scope because the fact
// that some access does not alias with any set of our noalias arguments
// cannot itself guarantee that it does not alias with this access
// (because there is some pointer of unknown origin involved and the
// other access might also depend on this pointer). We also cannot add
// scopes to arbitrary functions unless we know they don't access any
// non-parameter pointer-values.
bool CanAddScopes = !UsesAliasingPtr;
if (CanAddScopes && IsFuncCall)
CanAddScopes = IsArgMemOnlyCall;
if (CanAddScopes)
for (const Argument *A : NoAliasArgs) {
if (ObjSet.count(A))
Scopes.push_back(NewScopes[A]);
}
if (!Scopes.empty())
NI->setMetadata(
LLVMContext::MD_alias_scope,
MDNode::concatenate(NI->getMetadata(LLVMContext::MD_alias_scope),
MDNode::get(CalledFunc->getContext(), Scopes)));
}
}
}
/// If the inlined function has non-byval align arguments, then
/// add @llvm.assume-based alignment assumptions to preserve this information.
static void AddAlignmentAssumptions(CallSite CS, InlineFunctionInfo &IFI) {
if (!PreserveAlignmentAssumptions || !IFI.GetAssumptionCache)
return;
AssumptionCache *AC = &(*IFI.GetAssumptionCache)(*CS.getCaller());
auto &DL = CS.getCaller()->getParent()->getDataLayout();
// To avoid inserting redundant assumptions, we should check for assumptions
// already in the caller. To do this, we might need a DT of the caller.
DominatorTree DT;
bool DTCalculated = false;
Function *CalledFunc = CS.getCalledFunction();
for (Argument &Arg : CalledFunc->args()) {
unsigned Align = Arg.getType()->isPointerTy() ? Arg.getParamAlignment() : 0;
if (Align && !Arg.hasByValOrInAllocaAttr() && !Arg.hasNUses(0)) {
if (!DTCalculated) {
DT.recalculate(*CS.getCaller());
DTCalculated = true;
}
// If we can already prove the asserted alignment in the context of the
// caller, then don't bother inserting the assumption.
Value *ArgVal = CS.getArgument(Arg.getArgNo());
if (getKnownAlignment(ArgVal, DL, CS.getInstruction(), AC, &DT) >= Align)
continue;
CallInst *NewAsmp = IRBuilder<>(CS.getInstruction())
.CreateAlignmentAssumption(DL, ArgVal, Align);
AC->registerAssumption(NewAsmp);
}
}
}
/// Once we have cloned code over from a callee into the caller,
/// update the specified callgraph to reflect the changes we made.
/// Note that it's possible that not all code was copied over, so only
/// some edges of the callgraph may remain.
static void UpdateCallGraphAfterInlining(CallSite CS,
Function::iterator FirstNewBlock,
ValueToValueMapTy &VMap,
InlineFunctionInfo &IFI) {
CallGraph &CG = *IFI.CG;
const Function *Caller = CS.getCaller();
const Function *Callee = CS.getCalledFunction();
CallGraphNode *CalleeNode = CG[Callee];
CallGraphNode *CallerNode = CG[Caller];
// Since we inlined some uninlined call sites in the callee into the caller,
// add edges from the caller to all of the callees of the callee.
CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();
// Consider the case where CalleeNode == CallerNode.
CallGraphNode::CalledFunctionsVector CallCache;
if (CalleeNode == CallerNode) {
CallCache.assign(I, E);
I = CallCache.begin();
E = CallCache.end();
}
for (; I != E; ++I) {
const Value *OrigCall = I->first;
ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
// Only copy the edge if the call was inlined!
if (VMI == VMap.end() || VMI->second == nullptr)
continue;
// If the call was inlined, but then constant folded, there is no edge to
// add. Check for this case.
auto *NewCall = dyn_cast<CallBase>(VMI->second);
if (!NewCall)
continue;
// We do not treat intrinsic calls like real function calls because we
// expect them to become inline code; do not add an edge for an intrinsic.
if (NewCall->getCalledFunction() &&
NewCall->getCalledFunction()->isIntrinsic())
continue;
// Remember that this call site got inlined for the client of
// InlineFunction.
IFI.InlinedCalls.push_back(NewCall);
// It's possible that inlining the callsite will cause it to go from an
// indirect to a direct call by resolving a function pointer. If this
// happens, set the callee of the new call site to a more precise
// destination. This can also happen if the call graph node of the caller
// was just unnecessarily imprecise.
if (!I->second->getFunction())
if (Function *F = NewCall->getCalledFunction()) {
// Indirect call site resolved to direct call.
CallerNode->addCalledFunction(NewCall, CG[F]);
continue;
}
CallerNode->addCalledFunction(NewCall, I->second);
}
// Update the call graph by deleting the edge from Callee to Caller. We must
// do this after the loop above in case Caller and Callee are the same.
CallerNode->removeCallEdgeFor(*cast<CallBase>(CS.getInstruction()));
}
static void HandleByValArgumentInit(Value *Dst, Value *Src, Module *M,
BasicBlock *InsertBlock,
InlineFunctionInfo &IFI) {
Type *AggTy = cast<PointerType>(Src->getType())->getElementType();
IRBuilder<> Builder(InsertBlock, InsertBlock->begin());
Value *Size = Builder.getInt64(M->getDataLayout().getTypeStoreSize(AggTy));
// Always generate a memcpy of alignment 1 here because we don't know
// the alignment of the src pointer. Other optimizations can infer
// better alignment.
Builder.CreateMemCpy(Dst, /*DstAlign*/ Align::None(), Src,
/*SrcAlign*/ Align::None(), Size);
}
/// When inlining a call site that has a byval argument,
/// we have to make the implicit memcpy explicit by adding it.
static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
const Function *CalledFunc,
InlineFunctionInfo &IFI,
unsigned ByValAlignment) {
PointerType *ArgTy = cast<PointerType>(Arg->getType());
Type *AggTy = ArgTy->getElementType();
Function *Caller = TheCall->getFunction();
const DataLayout &DL = Caller->getParent()->getDataLayout();
// If the called function is readonly, then it could not mutate the caller's
// copy of the byval'd memory. In this case, it is safe to elide the copy and
// temporary.
if (CalledFunc->onlyReadsMemory()) {
// If the byval argument has a specified alignment that is greater than the
// passed in pointer, then we either have to round up the input pointer or
// give up on this transformation.
if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
return Arg;
AssumptionCache *AC =
IFI.GetAssumptionCache ? &(*IFI.GetAssumptionCache)(*Caller) : nullptr;
// If the pointer is already known to be sufficiently aligned, or if we can
// round it up to a larger alignment, then we don't need a temporary.
if (getOrEnforceKnownAlignment(Arg, ByValAlignment, DL, TheCall, AC) >=
ByValAlignment)
return Arg;
// Otherwise, we have to make a memcpy to get a safe alignment. This is bad
// for code quality, but rarely happens and is required for correctness.
}
// Create the alloca. If we have DataLayout, use nice alignment.
Align Alignment(DL.getPrefTypeAlignment(AggTy));
// If the byval had an alignment specified, we *must* use at least that
// alignment, as it is required by the byval argument (and uses of the
// pointer inside the callee).
Alignment = max(Alignment, MaybeAlign(ByValAlignment));
Value *NewAlloca =
new AllocaInst(AggTy, DL.getAllocaAddrSpace(), nullptr, Alignment,
Arg->getName(), &*Caller->begin()->begin());
IFI.StaticAllocas.push_back(cast<AllocaInst>(NewAlloca));
// Uses of the argument in the function should use our new alloca
// instead.
return NewAlloca;
}
// Check whether this Value is used by a lifetime intrinsic.
static bool isUsedByLifetimeMarker(Value *V) {
for (User *U : V->users())
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U))
if (II->isLifetimeStartOrEnd())
return true;
return false;
}
// Check whether the given alloca already has
// lifetime.start or lifetime.end intrinsics.
static bool hasLifetimeMarkers(AllocaInst *AI) {
Type *Ty = AI->getType();
Type *Int8PtrTy = Type::getInt8PtrTy(Ty->getContext(),
Ty->getPointerAddressSpace());
if (Ty == Int8PtrTy)
return isUsedByLifetimeMarker(AI);
// Do a scan to find all the casts to i8*.
for (User *U : AI->users()) {
if (U->getType() != Int8PtrTy) continue;
if (U->stripPointerCasts() != AI) continue;
if (isUsedByLifetimeMarker(U))
return true;
}
return false;
}
/// Return the result of AI->isStaticAlloca() if AI were moved to the entry
/// block. Allocas used in inalloca calls and allocas of dynamic array size
/// cannot be static.
static bool allocaWouldBeStaticInEntry(const AllocaInst *AI ) {
return isa<Constant>(AI->getArraySize()) && !AI->isUsedWithInAlloca();
}
/// Returns a DebugLoc for a new DILocation which is a clone of \p OrigDL
/// inlined at \p InlinedAt. \p IANodes is an inlined-at cache.
static DebugLoc inlineDebugLoc(DebugLoc OrigDL, DILocation *InlinedAt,
LLVMContext &Ctx,
DenseMap<const MDNode *, MDNode *> &IANodes) {
auto IA = DebugLoc::appendInlinedAt(OrigDL, InlinedAt, Ctx, IANodes);
return DebugLoc::get(OrigDL.getLine(), OrigDL.getCol(), OrigDL.getScope(),
IA);
}
/// Returns the LoopID for a loop which has has been cloned from another
/// function for inlining with the new inlined-at start and end locs.
static MDNode *inlineLoopID(const MDNode *OrigLoopId, DILocation *InlinedAt,
LLVMContext &Ctx,
DenseMap<const MDNode *, MDNode *> &IANodes) {
assert(OrigLoopId && OrigLoopId->getNumOperands() > 0 &&
"Loop ID needs at least one operand");
assert(OrigLoopId && OrigLoopId->getOperand(0).get() == OrigLoopId &&
"Loop ID should refer to itself");
// Save space for the self-referential LoopID.
SmallVector<Metadata *, 4> MDs = {nullptr};
for (unsigned i = 1; i < OrigLoopId->getNumOperands(); ++i) {
Metadata *MD = OrigLoopId->getOperand(i);
// Update the DILocations to encode the inlined-at metadata.
if (DILocation *DL = dyn_cast<DILocation>(MD))
MDs.push_back(inlineDebugLoc(DL, InlinedAt, Ctx, IANodes));
else
MDs.push_back(MD);
}
MDNode *NewLoopID = MDNode::getDistinct(Ctx, MDs);
// Insert the self-referential LoopID.
NewLoopID->replaceOperandWith(0, NewLoopID);
return NewLoopID;
}
/// Update inlined instructions' line numbers to
/// to encode location where these instructions are inlined.
static void fixupLineNumbers(Function *Fn, Function::iterator FI,
Instruction *TheCall, bool CalleeHasDebugInfo) {
const DebugLoc &TheCallDL = TheCall->getDebugLoc();
if (!TheCallDL)
return;
auto &Ctx = Fn->getContext();
DILocation *InlinedAtNode = TheCallDL;
// Create a unique call site, not to be confused with any other call from the
// same location.
InlinedAtNode = DILocation::getDistinct(
Ctx, InlinedAtNode->getLine(), InlinedAtNode->getColumn(),
InlinedAtNode->getScope(), InlinedAtNode->getInlinedAt());
// Cache the inlined-at nodes as they're built so they are reused, without
// this every instruction's inlined-at chain would become distinct from each
// other.
DenseMap<const MDNode *, MDNode *> IANodes;
// Check if we are not generating inline line tables and want to use
// the call site location instead.
bool NoInlineLineTables = Fn->hasFnAttribute("no-inline-line-tables");
for (; FI != Fn->end(); ++FI) {
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
// Loop metadata needs to be updated so that the start and end locs
// reference inlined-at locations.
if (MDNode *LoopID = BI->getMetadata(LLVMContext::MD_loop)) {
MDNode *NewLoopID =
inlineLoopID(LoopID, InlinedAtNode, BI->getContext(), IANodes);
BI->setMetadata(LLVMContext::MD_loop, NewLoopID);
}
if (!NoInlineLineTables)
if (DebugLoc DL = BI->getDebugLoc()) {
DebugLoc IDL =
inlineDebugLoc(DL, InlinedAtNode, BI->getContext(), IANodes);
BI->setDebugLoc(IDL);
continue;
}
if (CalleeHasDebugInfo && !NoInlineLineTables)
continue;
// If the inlined instruction has no line number, or if inline info
// is not being generated, make it look as if it originates from the call
// location. This is important for ((__always_inline, __nodebug__))
// functions which must use caller location for all instructions in their
// function body.
// Don't update static allocas, as they may get moved later.
if (auto *AI = dyn_cast<AllocaInst>(BI))
if (allocaWouldBeStaticInEntry(AI))
continue;
BI->setDebugLoc(TheCallDL);
}
// Remove debug info intrinsics if we're not keeping inline info.
if (NoInlineLineTables) {
BasicBlock::iterator BI = FI->begin();
while (BI != FI->end()) {
if (isa<DbgInfoIntrinsic>(BI)) {
BI = BI->eraseFromParent();
continue;
}
++BI;
}
}
}
}
/// Update the block frequencies of the caller after a callee has been inlined.
///
/// Each block cloned into the caller has its block frequency scaled by the
/// ratio of CallSiteFreq/CalleeEntryFreq. This ensures that the cloned copy of
/// callee's entry block gets the same frequency as the callsite block and the
/// relative frequencies of all cloned blocks remain the same after cloning.
static void updateCallerBFI(BasicBlock *CallSiteBlock,
const ValueToValueMapTy &VMap,
BlockFrequencyInfo *CallerBFI,
BlockFrequencyInfo *CalleeBFI,
const BasicBlock &CalleeEntryBlock) {
SmallPtrSet<BasicBlock *, 16> ClonedBBs;
for (auto Entry : VMap) {
if (!isa<BasicBlock>(Entry.first) || !Entry.second)
continue;
auto *OrigBB = cast<BasicBlock>(Entry.first);
auto *ClonedBB = cast<BasicBlock>(Entry.second);
uint64_t Freq = CalleeBFI->getBlockFreq(OrigBB).getFrequency();
if (!ClonedBBs.insert(ClonedBB).second) {
// Multiple blocks in the callee might get mapped to one cloned block in
// the caller since we prune the callee as we clone it. When that happens,
// we want to use the maximum among the original blocks' frequencies.
uint64_t NewFreq = CallerBFI->getBlockFreq(ClonedBB).getFrequency();
if (NewFreq > Freq)
Freq = NewFreq;
}
CallerBFI->setBlockFreq(ClonedBB, Freq);
}
BasicBlock *EntryClone = cast<BasicBlock>(VMap.lookup(&CalleeEntryBlock));
CallerBFI->setBlockFreqAndScale(
EntryClone, CallerBFI->getBlockFreq(CallSiteBlock).getFrequency(),
ClonedBBs);
}
/// Update the branch metadata for cloned call instructions.
static void updateCallProfile(Function *Callee, const ValueToValueMapTy &VMap,
const ProfileCount &CalleeEntryCount,
const Instruction *TheCall,
ProfileSummaryInfo *PSI,
BlockFrequencyInfo *CallerBFI) {
if (!CalleeEntryCount.hasValue() || CalleeEntryCount.isSynthetic() ||
CalleeEntryCount.getCount() < 1)
return;
auto CallSiteCount = PSI ? PSI->getProfileCount(TheCall, CallerBFI) : None;
int64_t CallCount =
std::min(CallSiteCount.hasValue() ? CallSiteCount.getValue() : 0,
CalleeEntryCount.getCount());
updateProfileCallee(Callee, -CallCount, &VMap);
}
void llvm::updateProfileCallee(
Function *Callee, int64_t entryDelta,
const ValueMap<const Value *, WeakTrackingVH> *VMap) {
auto CalleeCount = Callee->getEntryCount();
if (!CalleeCount.hasValue())
return;
uint64_t priorEntryCount = CalleeCount.getCount();
uint64_t newEntryCount;
// Since CallSiteCount is an estimate, it could exceed the original callee
// count and has to be set to 0 so guard against underflow.
if (entryDelta < 0 && static_cast<uint64_t>(-entryDelta) > priorEntryCount)
newEntryCount = 0;
else
newEntryCount = priorEntryCount + entryDelta;
// During inlining ?
if (VMap) {
uint64_t cloneEntryCount = priorEntryCount - newEntryCount;
for (auto Entry : *VMap)
if (isa<CallInst>(Entry.first))
if (auto *CI = dyn_cast_or_null<CallInst>(Entry.second))
CI->updateProfWeight(cloneEntryCount, priorEntryCount);
}
if (entryDelta) {
Callee->setEntryCount(newEntryCount);
for (BasicBlock &BB : *Callee)
// No need to update the callsite if it is pruned during inlining.
if (!VMap || VMap->count(&BB))
for (Instruction &I : BB)
if (CallInst *CI = dyn_cast<CallInst>(&I))
CI->updateProfWeight(newEntryCount, priorEntryCount);
}
}
/// This function inlines the called function into the basic block of the
/// caller. This returns false if it is not possible to inline this call.
/// The program is still in a well defined state if this occurs though.
///
/// Note that this only does one level of inlining. For example, if the
/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
/// exists in the instruction stream. Similarly this will inline a recursive
/// function by one level.
llvm::InlineResult llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
AAResults *CalleeAAR,
bool InsertLifetime,
Function *ForwardVarArgsTo) {
Instruction *TheCall = CS.getInstruction();
assert(TheCall->getParent() && TheCall->getFunction()
&& "Instruction not in function!");
// FIXME: we don't inline callbr yet.
if (isa<CallBrInst>(TheCall))
return false;
// If IFI has any state in it, zap it before we fill it in.
IFI.reset();
Function *CalledFunc = CS.getCalledFunction();
if (!CalledFunc || // Can't inline external function or indirect
CalledFunc->isDeclaration()) // call!
return "external or indirect";
// The inliner does not know how to inline through calls with operand bundles
// in general ...
if (CS.hasOperandBundles()) {
for (int i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
uint32_t Tag = CS.getOperandBundleAt(i).getTagID();
// ... but it knows how to inline through "deopt" operand bundles ...
if (Tag == LLVMContext::OB_deopt)
continue;
// ... and "funclet" operand bundles.
if (Tag == LLVMContext::OB_funclet)
continue;
return "unsupported operand bundle";
}
}
// If the call to the callee cannot throw, set the 'nounwind' flag on any
// calls that we inline.
bool MarkNoUnwind = CS.doesNotThrow();
BasicBlock *OrigBB = TheCall->getParent();
Function *Caller = OrigBB->getParent();
// GC poses two hazards to inlining, which only occur when the callee has GC:
// 1. If the caller has no GC, then the callee's GC must be propagated to the
// caller.
// 2. If the caller has a differing GC, it is invalid to inline.
if (CalledFunc->hasGC()) {
if (!Caller->hasGC())
Caller->setGC(CalledFunc->getGC());
else if (CalledFunc->getGC() != Caller->getGC())
return "incompatible GC";
}
// Get the personality function from the callee if it contains a landing pad.
Constant *CalledPersonality =
CalledFunc->hasPersonalityFn()
? CalledFunc->getPersonalityFn()->stripPointerCasts()
: nullptr;
// Find the personality function used by the landing pads of the caller. If it
// exists, then check to see that it matches the personality function used in
// the callee.
Constant *CallerPersonality =
Caller->hasPersonalityFn()
? Caller->getPersonalityFn()->stripPointerCasts()
: nullptr;
if (CalledPersonality) {
if (!CallerPersonality)
Caller->setPersonalityFn(CalledPersonality);
// If the personality functions match, then we can perform the
// inlining. Otherwise, we can't inline.
// TODO: This isn't 100% true. Some personality functions are proper
// supersets of others and can be used in place of the other.
else if (CalledPersonality != CallerPersonality)
return "incompatible personality";
}
// We need to figure out which funclet the callsite was in so that we may
// properly nest the callee.
Instruction *CallSiteEHPad = nullptr;
if (CallerPersonality) {
EHPersonality Personality = classifyEHPersonality(CallerPersonality);
if (isScopedEHPersonality(Personality)) {
Optional<OperandBundleUse> ParentFunclet =
CS.getOperandBundle(LLVMContext::OB_funclet);
if (ParentFunclet)
CallSiteEHPad = cast<FuncletPadInst>(ParentFunclet->Inputs.front());
// OK, the inlining site is legal. What about the target function?
if (CallSiteEHPad) {
if (Personality == EHPersonality::MSVC_CXX) {
// The MSVC personality cannot tolerate catches getting inlined into
// cleanup funclets.
if (isa<CleanupPadInst>(CallSiteEHPad)) {
// Ok, the call site is within a cleanuppad. Let's check the callee
// for catchpads.
for (const BasicBlock &CalledBB : *CalledFunc) {
if (isa<CatchSwitchInst>(CalledBB.getFirstNonPHI()))
return "catch in cleanup funclet";
}
}
} else if (isAsynchronousEHPersonality(Personality)) {
// SEH is even less tolerant, there may not be any sort of exceptional
// funclet in the callee.
for (const BasicBlock &CalledBB : *CalledFunc) {
if (CalledBB.isEHPad())
return "SEH in cleanup funclet";
}
}
}
}
}
// Determine if we are dealing with a call in an EHPad which does not unwind
// to caller.
bool EHPadForCallUnwindsLocally = false;
if (CallSiteEHPad && CS.isCall()) {
UnwindDestMemoTy FuncletUnwindMap;
Value *CallSiteUnwindDestToken =
getUnwindDestToken(CallSiteEHPad, FuncletUnwindMap);
EHPadForCallUnwindsLocally =
CallSiteUnwindDestToken &&
!isa<ConstantTokenNone>(CallSiteUnwindDestToken);
}
// Get an iterator to the last basic block in the function, which will have
// the new function inlined after it.
Function::iterator LastBlock = --Caller->end();
// Make sure to capture all of the return instructions from the cloned
// function.
SmallVector<ReturnInst*, 8> Returns;
ClonedCodeInfo InlinedFunctionInfo;
Function::iterator FirstNewBlock;
{ // Scope to destroy VMap after cloning.
ValueToValueMapTy VMap;
// Keep a list of pair (dst, src) to emit byval initializations.
SmallVector<std::pair<Value*, Value*>, 4> ByValInit;
auto &DL = Caller->getParent()->getDataLayout();
// Calculate the vector of arguments to pass into the function cloner, which
// matches up the formal to the actual argument values.
CallSite::arg_iterator AI = CS.arg_begin();
unsigned ArgNo = 0;
for (Function::arg_iterator I = CalledFunc->arg_begin(),
E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
Value *ActualArg = *AI;
// When byval arguments actually inlined, we need to make the copy implied
// by them explicit. However, we don't do this if the callee is readonly
// or readnone, because the copy would be unneeded: the callee doesn't
// modify the struct.
if (CS.isByValArgument(ArgNo)) {
ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
CalledFunc->getParamAlignment(ArgNo));
if (ActualArg != *AI)
ByValInit.push_back(std::make_pair(ActualArg, (Value*) *AI));
}
VMap[&*I] = ActualArg;
}
// Add alignment assumptions if necessary. We do this before the inlined
// instructions are actually cloned into the caller so that we can easily
// check what will be known at the start of the inlined code.
AddAlignmentAssumptions(CS, IFI);
// We want the inliner to prune the code as it copies. We would LOVE to
// have no dead or constant instructions leftover after inlining occurs
// (which can happen, e.g., because an argument was constant), but we'll be
// happy with whatever the cloner can do.
CloneAndPruneFunctionInto(Caller, CalledFunc, VMap,
/*ModuleLevelChanges=*/false, Returns, ".i",
&InlinedFunctionInfo, TheCall);
// Remember the first block that is newly cloned over.
FirstNewBlock = LastBlock; ++FirstNewBlock;
if (IFI.CallerBFI != nullptr && IFI.CalleeBFI != nullptr)
// Update the BFI of blocks cloned into the caller.
updateCallerBFI(OrigBB, VMap, IFI.CallerBFI, IFI.CalleeBFI,
CalledFunc->front());
updateCallProfile(CalledFunc, VMap, CalledFunc->getEntryCount(), TheCall,
IFI.PSI, IFI.CallerBFI);
// Inject byval arguments initialization.
for (std::pair<Value*, Value*> &Init : ByValInit)
HandleByValArgumentInit(Init.first, Init.second, Caller->getParent(),
&*FirstNewBlock, IFI);
Optional<OperandBundleUse> ParentDeopt =
CS.getOperandBundle(LLVMContext::OB_deopt);
if (ParentDeopt) {
SmallVector<OperandBundleDef, 2> OpDefs;
for (auto &VH : InlinedFunctionInfo.OperandBundleCallSites) {
Instruction *I = dyn_cast_or_null<Instruction>(VH);
if (!I) continue; // instruction was DCE'd or RAUW'ed to undef
OpDefs.clear();
CallSite ICS(I);
OpDefs.reserve(ICS.getNumOperandBundles());
for (unsigned i = 0, e = ICS.getNumOperandBundles(); i < e; ++i) {
auto ChildOB = ICS.getOperandBundleAt(i);
if (ChildOB.getTagID() != LLVMContext::OB_deopt) {
// If the inlined call has other operand bundles, let them be
OpDefs.emplace_back(ChildOB);
continue;
}
// It may be useful to separate this logic (of handling operand
// bundles) out to a separate "policy" component if this gets crowded.
// Prepend the parent's deoptimization continuation to the newly
// inlined call's deoptimization continuation.
std::vector<Value *> MergedDeoptArgs;
MergedDeoptArgs.reserve(ParentDeopt->Inputs.size() +
ChildOB.Inputs.size());
MergedDeoptArgs.insert(MergedDeoptArgs.end(),
ParentDeopt->Inputs.begin(),
ParentDeopt->Inputs.end());
MergedDeoptArgs.insert(MergedDeoptArgs.end(), ChildOB.Inputs.begin(),
ChildOB.Inputs.end());
OpDefs.emplace_back("deopt", std::move(MergedDeoptArgs));
}
Instruction *NewI = nullptr;
if (isa<CallInst>(I))
NewI = CallInst::Create(cast<CallInst>(I), OpDefs, I);
else if (isa<CallBrInst>(I))
NewI = CallBrInst::Create(cast<CallBrInst>(I), OpDefs, I);
else
NewI = InvokeInst::Create(cast<InvokeInst>(I), OpDefs, I);
// Note: the RAUW does the appropriate fixup in VMap, so we need to do
// this even if the call returns void.
I->replaceAllUsesWith(NewI);
VH = nullptr;
I->eraseFromParent();
}
}
// Update the callgraph if requested.
if (IFI.CG)
UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
// For 'nodebug' functions, the associated DISubprogram is always null.
// Conservatively avoid propagating the callsite debug location to
// instructions inlined from a function whose DISubprogram is not null.
fixupLineNumbers(Caller, FirstNewBlock, TheCall,
CalledFunc->getSubprogram() != nullptr);
// Clone existing noalias metadata if necessary.
CloneAliasScopeMetadata(CS, VMap);
// Add noalias metadata if necessary.
AddAliasScopeMetadata(CS, VMap, DL, CalleeAAR);
// Propagate llvm.mem.parallel_loop_access if necessary.
PropagateParallelLoopAccessMetadata(CS, VMap);
// Register any cloned assumptions.
if (IFI.GetAssumptionCache)
for (BasicBlock &NewBlock :
make_range(FirstNewBlock->getIterator(), Caller->end()))
for (Instruction &I : NewBlock) {
if (auto *II = dyn_cast<IntrinsicInst>(&I))
if (II->getIntrinsicID() == Intrinsic::assume)
(*IFI.GetAssumptionCache)(*Caller).registerAssumption(II);
}
}
// If there are any alloca instructions in the block that used to be the entry
// block for the callee, move them to the entry block of the caller. First
// calculate which instruction they should be inserted before. We insert the
// instructions at the end of the current alloca list.
{
BasicBlock::iterator InsertPoint = Caller->begin()->begin();
for (BasicBlock::iterator I = FirstNewBlock->begin(),
E = FirstNewBlock->end(); I != E; ) {
AllocaInst *AI = dyn_cast<AllocaInst>(I++);
if (!AI) continue;
// If the alloca is now dead, remove it. This often occurs due to code
// specialization.
if (AI->use_empty()) {
AI->eraseFromParent();
continue;
}
if (!allocaWouldBeStaticInEntry(AI))
continue;
// Keep track of the static allocas that we inline into the caller.
IFI.StaticAllocas.push_back(AI);
// Scan for the block of allocas that we can move over, and move them
// all at once.
while (isa<AllocaInst>(I) &&
!cast<AllocaInst>(I)->use_empty() &&
allocaWouldBeStaticInEntry(cast<AllocaInst>(I))) {
IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
++I;
}
// Transfer all of the allocas over in a block. Using splice means
// that the instructions aren't removed from the symbol table, then
// reinserted.
Caller->getEntryBlock().getInstList().splice(
InsertPoint, FirstNewBlock->getInstList(), AI->getIterator(), I);
}
// Move any dbg.declares describing the allocas into the entry basic block.
DIBuilder DIB(*Caller->getParent());
for (auto &AI : IFI.StaticAllocas)
replaceDbgDeclareForAlloca(AI, AI, DIB, DIExpression::ApplyOffset, 0);
}
SmallVector<Value*,4> VarArgsToForward;
SmallVector<AttributeSet, 4> VarArgsAttrs;
for (unsigned i = CalledFunc->getFunctionType()->getNumParams();
i < CS.getNumArgOperands(); i++) {
VarArgsToForward.push_back(CS.getArgOperand(i));
VarArgsAttrs.push_back(CS.getAttributes().getParamAttributes(i));
}
bool InlinedMustTailCalls = false, InlinedDeoptimizeCalls = false;
if (InlinedFunctionInfo.ContainsCalls) {
CallInst::TailCallKind CallSiteTailKind = CallInst::TCK_None;
if (CallInst *CI = dyn_cast<CallInst>(TheCall))
CallSiteTailKind = CI->getTailCallKind();
// For inlining purposes, the "notail" marker is the same as no marker.
if (CallSiteTailKind == CallInst::TCK_NoTail)
CallSiteTailKind = CallInst::TCK_None;
for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E;
++BB) {
for (auto II = BB->begin(); II != BB->end();) {
Instruction &I = *II++;
CallInst *CI = dyn_cast<CallInst>(&I);
if (!CI)
continue;
// Forward varargs from inlined call site to calls to the
// ForwardVarArgsTo function, if requested, and to musttail calls.
if (!VarArgsToForward.empty() &&
((ForwardVarArgsTo &&
CI->getCalledFunction() == ForwardVarArgsTo) ||
CI->isMustTailCall())) {
// Collect attributes for non-vararg parameters.
AttributeList Attrs = CI->getAttributes();
SmallVector<AttributeSet, 8> ArgAttrs;
if (!Attrs.isEmpty() || !VarArgsAttrs.empty()) {
for (unsigned ArgNo = 0;
ArgNo < CI->getFunctionType()->getNumParams(); ++ArgNo)
ArgAttrs.push_back(Attrs.getParamAttributes(ArgNo));
}
// Add VarArg attributes.
ArgAttrs.append(VarArgsAttrs.begin(), VarArgsAttrs.end());
Attrs = AttributeList::get(CI->getContext(), Attrs.getFnAttributes(),
Attrs.getRetAttributes(), ArgAttrs);
// Add VarArgs to existing parameters.
SmallVector<Value *, 6> Params(CI->arg_operands());
Params.append(VarArgsToForward.begin(), VarArgsToForward.end());
CallInst *NewCI = CallInst::Create(
CI->getFunctionType(), CI->getCalledOperand(), Params, "", CI);
NewCI->setDebugLoc(CI->getDebugLoc());
NewCI->setAttributes(Attrs);
NewCI->setCallingConv(CI->getCallingConv());
CI->replaceAllUsesWith(NewCI);
CI->eraseFromParent();
CI = NewCI;
}
if (Function *F = CI->getCalledFunction())
InlinedDeoptimizeCalls |=
F->getIntrinsicID() == Intrinsic::experimental_deoptimize;
// We need to reduce the strength of any inlined tail calls. For
// musttail, we have to avoid introducing potential unbounded stack
// growth. For example, if functions 'f' and 'g' are mutually recursive
// with musttail, we can inline 'g' into 'f' so long as we preserve
// musttail on the cloned call to 'f'. If either the inlined call site
// or the cloned call site is *not* musttail, the program already has
// one frame of stack growth, so it's safe to remove musttail. Here is
// a table of example transformations:
//
// f -> musttail g -> musttail f ==> f -> musttail f
// f -> musttail g -> tail f ==> f -> tail f
// f -> g -> musttail f ==> f -> f
// f -> g -> tail f ==> f -> f
//
// Inlined notail calls should remain notail calls.
CallInst::TailCallKind ChildTCK = CI->getTailCallKind();
if (ChildTCK != CallInst::TCK_NoTail)
ChildTCK = std::min(CallSiteTailKind, ChildTCK);
CI->setTailCallKind(ChildTCK);
InlinedMustTailCalls |= CI->isMustTailCall();
// Calls inlined through a 'nounwind' call site should be marked
// 'nounwind'.
if (MarkNoUnwind)
CI->setDoesNotThrow();
}
}
}
// Leave lifetime markers for the static alloca's, scoping them to the
// function we just inlined.
if (InsertLifetime && !IFI.StaticAllocas.empty()) {
IRBuilder<> builder(&FirstNewBlock->front());
for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
AllocaInst *AI = IFI.StaticAllocas[ai];
// Don't mark swifterror allocas. They can't have bitcast uses.
if (AI->isSwiftError())
continue;
// If the alloca is already scoped to something smaller than the whole
// function then there's no need to add redundant, less accurate markers.
if (hasLifetimeMarkers(AI))
continue;
// Try to determine the size of the allocation.
ConstantInt *AllocaSize = nullptr;
if (ConstantInt *AIArraySize =
dyn_cast<ConstantInt>(AI->getArraySize())) {
auto &DL = Caller->getParent()->getDataLayout();
Type *AllocaType = AI->getAllocatedType();
uint64_t AllocaTypeSize = DL.getTypeAllocSize(AllocaType);
uint64_t AllocaArraySize = AIArraySize->getLimitedValue();
// Don't add markers for zero-sized allocas.
if (AllocaArraySize == 0)
continue;
// Check that array size doesn't saturate uint64_t and doesn't
// overflow when it's multiplied by type size.
if (AllocaArraySize != std::numeric_limits<uint64_t>::max() &&
std::numeric_limits<uint64_t>::max() / AllocaArraySize >=
AllocaTypeSize) {
AllocaSize = ConstantInt::get(Type::getInt64Ty(AI->getContext()),
AllocaArraySize * AllocaTypeSize);
}
}
builder.CreateLifetimeStart(AI, AllocaSize);
for (ReturnInst *RI : Returns) {
// Don't insert llvm.lifetime.end calls between a musttail or deoptimize
// call and a return. The return kills all local allocas.
if (InlinedMustTailCalls &&
RI->getParent()->getTerminatingMustTailCall())
continue;
if (InlinedDeoptimizeCalls &&
RI->getParent()->getTerminatingDeoptimizeCall())
continue;
IRBuilder<>(RI).CreateLifetimeEnd(AI, AllocaSize);
}
}
}
// If the inlined code contained dynamic alloca instructions, wrap the inlined
// code with llvm.stacksave/llvm.stackrestore intrinsics.
if (InlinedFunctionInfo.ContainsDynamicAllocas) {
Module *M = Caller->getParent();
// Get the two intrinsics we care about.
Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);
// Insert the llvm.stacksave.
CallInst *SavedPtr = IRBuilder<>(&*FirstNewBlock, FirstNewBlock->begin())
.CreateCall(StackSave, {}, "savedstack");
// Insert a call to llvm.stackrestore before any return instructions in the
// inlined function.
for (ReturnInst *RI : Returns) {
// Don't insert llvm.stackrestore calls between a musttail or deoptimize
// call and a return. The return will restore the stack pointer.
if (InlinedMustTailCalls && RI->getParent()->getTerminatingMustTailCall())
continue;
if (InlinedDeoptimizeCalls && RI->getParent()->getTerminatingDeoptimizeCall())
continue;
IRBuilder<>(RI).CreateCall(StackRestore, SavedPtr);
}
}
// If we are inlining for an invoke instruction, we must make sure to rewrite
// any call instructions into invoke instructions. This is sensitive to which
// funclet pads were top-level in the inlinee, so must be done before
// rewriting the "parent pad" links.
if (auto *II = dyn_cast<InvokeInst>(TheCall)) {
BasicBlock *UnwindDest = II->getUnwindDest();
Instruction *FirstNonPHI = UnwindDest->getFirstNonPHI();
if (isa<LandingPadInst>(FirstNonPHI)) {
HandleInlinedLandingPad(II, &*FirstNewBlock, InlinedFunctionInfo);
} else {
HandleInlinedEHPad(II, &*FirstNewBlock, InlinedFunctionInfo);
}
}
// Update the lexical scopes of the new funclets and callsites.
// Anything that had 'none' as its parent is now nested inside the callsite's
// EHPad.
if (CallSiteEHPad) {
for (Function::iterator BB = FirstNewBlock->getIterator(),
E = Caller->end();
BB != E; ++BB) {
// Add bundle operands to any top-level call sites.
SmallVector<OperandBundleDef, 1> OpBundles;
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;) {
Instruction *I = &*BBI++;
CallSite CS(I);
if (!CS)
continue;
// Skip call sites which are nounwind intrinsics.
auto *CalledFn =
dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts());
if (CalledFn && CalledFn->isIntrinsic() && CS.doesNotThrow())
continue;
// Skip call sites which already have a "funclet" bundle.
if (CS.getOperandBundle(LLVMContext::OB_funclet))
continue;
CS.getOperandBundlesAsDefs(OpBundles);
OpBundles.emplace_back("funclet", CallSiteEHPad);
Instruction *NewInst;
if (CS.isCall())
NewInst = CallInst::Create(cast<CallInst>(I), OpBundles, I);
else if (CS.isCallBr())
NewInst = CallBrInst::Create(cast<CallBrInst>(I), OpBundles, I);
else
NewInst = InvokeInst::Create(cast<InvokeInst>(I), OpBundles, I);
NewInst->takeName(I);
I->replaceAllUsesWith(NewInst);
I->eraseFromParent();
OpBundles.clear();
}
// It is problematic if the inlinee has a cleanupret which unwinds to
// caller and we inline it into a call site which doesn't unwind but into
// an EH pad that does. Such an edge must be dynamically unreachable.
// As such, we replace the cleanupret with unreachable.
if (auto *CleanupRet = dyn_cast<CleanupReturnInst>(BB->getTerminator()))
if (CleanupRet->unwindsToCaller() && EHPadForCallUnwindsLocally)
changeToUnreachable(CleanupRet, /*UseLLVMTrap=*/false);
Instruction *I = BB->getFirstNonPHI();
if (!I->isEHPad())
continue;
if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(I)) {
if (isa<ConstantTokenNone>(CatchSwitch->getParentPad()))
CatchSwitch->setParentPad(CallSiteEHPad);
} else {
auto *FPI = cast<FuncletPadInst>(I);
if (isa<ConstantTokenNone>(FPI->getParentPad()))
FPI->setParentPad(CallSiteEHPad);
}
}
}
if (InlinedDeoptimizeCalls) {
// We need to at least remove the deoptimizing returns from the Return set,
// so that the control flow from those returns does not get merged into the
// caller (but terminate it instead). If the caller's return type does not
// match the callee's return type, we also need to change the return type of
// the intrinsic.
if (Caller->getReturnType() == TheCall->getType()) {
auto NewEnd = llvm::remove_if(Returns, [](ReturnInst *RI) {
return RI->getParent()->getTerminatingDeoptimizeCall() != nullptr;
});
Returns.erase(NewEnd, Returns.end());
} else {
SmallVector<ReturnInst *, 8> NormalReturns;
Function *NewDeoptIntrinsic = Intrinsic::getDeclaration(
Caller->getParent(), Intrinsic::experimental_deoptimize,
{Caller->getReturnType()});
for (ReturnInst *RI : Returns) {
CallInst *DeoptCall = RI->getParent()->getTerminatingDeoptimizeCall();
if (!DeoptCall) {
NormalReturns.push_back(RI);
continue;
}
// The calling convention on the deoptimize call itself may be bogus,
// since the code we're inlining may have undefined behavior (and may
// never actually execute at runtime); but all
// @llvm.experimental.deoptimize declarations have to have the same
// calling convention in a well-formed module.
auto CallingConv = DeoptCall->getCalledFunction()->getCallingConv();
NewDeoptIntrinsic->setCallingConv(CallingConv);
auto *CurBB = RI->getParent();
RI->eraseFromParent();
SmallVector<Value *, 4> CallArgs(DeoptCall->arg_begin(),
DeoptCall->arg_end());
SmallVector<OperandBundleDef, 1> OpBundles;
DeoptCall->getOperandBundlesAsDefs(OpBundles);
DeoptCall->eraseFromParent();
assert(!OpBundles.empty() &&
"Expected at least the deopt operand bundle");
IRBuilder<> Builder(CurBB);
CallInst *NewDeoptCall =
Builder.CreateCall(NewDeoptIntrinsic, CallArgs, OpBundles);
NewDeoptCall->setCallingConv(CallingConv);
if (NewDeoptCall->getType()->isVoidTy())
Builder.CreateRetVoid();
else
Builder.CreateRet(NewDeoptCall);
}
// Leave behind the normal returns so we can merge control flow.
std::swap(Returns, NormalReturns);
}
}
// Handle any inlined musttail call sites. In order for a new call site to be
// musttail, the source of the clone and the inlined call site must have been
// musttail. Therefore it's safe to return without merging control into the
// phi below.
if (InlinedMustTailCalls) {
// Check if we need to bitcast the result of any musttail calls.
Type *NewRetTy = Caller->getReturnType();
bool NeedBitCast = !TheCall->use_empty() && TheCall->getType() != NewRetTy;
// Handle the returns preceded by musttail calls separately.
SmallVector<ReturnInst *, 8> NormalReturns;
for (ReturnInst *RI : Returns) {
CallInst *ReturnedMustTail =
RI->getParent()->getTerminatingMustTailCall();
if (!ReturnedMustTail) {
NormalReturns.push_back(RI);
continue;
}
if (!NeedBitCast)
continue;
// Delete the old return and any preceding bitcast.
BasicBlock *CurBB = RI->getParent();
auto *OldCast = dyn_cast_or_null<BitCastInst>(RI->getReturnValue());
RI->eraseFromParent();
if (OldCast)
OldCast->eraseFromParent();
// Insert a new bitcast and return with the right type.
IRBuilder<> Builder(CurBB);
Builder.CreateRet(Builder.CreateBitCast(ReturnedMustTail, NewRetTy));
}
// Leave behind the normal returns so we can merge control flow.
std::swap(Returns, NormalReturns);
}
// Now that all of the transforms on the inlined code have taken place but
// before we splice the inlined code into the CFG and lose track of which
// blocks were actually inlined, collect the call sites. We only do this if
// call graph updates weren't requested, as those provide value handle based
// tracking of inlined call sites instead.
if (InlinedFunctionInfo.ContainsCalls && !IFI.CG) {
// Otherwise just collect the raw call sites that were inlined.
for (BasicBlock &NewBB :
make_range(FirstNewBlock->getIterator(), Caller->end()))
for (Instruction &I : NewBB)
if (auto CS = CallSite(&I))
IFI.InlinedCallSites.push_back(CS);
}
// If we cloned in _exactly one_ basic block, and if that block ends in a
// return instruction, we splice the body of the inlined callee directly into
// the calling basic block.
if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
// Move all of the instructions right before the call.
OrigBB->getInstList().splice(TheCall->getIterator(),
FirstNewBlock->getInstList(),
FirstNewBlock->begin(), FirstNewBlock->end());
// Remove the cloned basic block.
Caller->getBasicBlockList().pop_back();
// If the call site was an invoke instruction, add a branch to the normal
// destination.
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall);
NewBr->setDebugLoc(Returns[0]->getDebugLoc());
}
// If the return instruction returned a value, replace uses of the call with
// uses of the returned value.
if (!TheCall->use_empty()) {
ReturnInst *R = Returns[0];
if (TheCall == R->getReturnValue())
TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(R->getReturnValue());
}
// Since we are now done with the Call/Invoke, we can delete it.
TheCall->eraseFromParent();
// Since we are now done with the return instruction, delete it also.
Returns[0]->eraseFromParent();
// We are now done with the inlining.
return true;
}
// Otherwise, we have the normal case, of more than one block to inline or
// multiple return sites.
// We want to clone the entire callee function into the hole between the
// "starter" and "ender" blocks. How we accomplish this depends on whether
// this is an invoke instruction or a call instruction.
BasicBlock *AfterCallBB;
BranchInst *CreatedBranchToNormalDest = nullptr;
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
// Add an unconditional branch to make this look like the CallInst case...
CreatedBranchToNormalDest = BranchInst::Create(II->getNormalDest(), TheCall);
// Split the basic block. This guarantees that no PHI nodes will have to be
// updated due to new incoming edges, and make the invoke case more
// symmetric to the call case.
AfterCallBB =
OrigBB->splitBasicBlock(CreatedBranchToNormalDest->getIterator(),
CalledFunc->getName() + ".exit");
} else { // It's a call
// If this is a call instruction, we need to split the basic block that
// the call lives in.
//
AfterCallBB = OrigBB->splitBasicBlock(TheCall->getIterator(),
CalledFunc->getName() + ".exit");
}
if (IFI.CallerBFI) {
// Copy original BB's block frequency to AfterCallBB
IFI.CallerBFI->setBlockFreq(
AfterCallBB, IFI.CallerBFI->getBlockFreq(OrigBB).getFrequency());
}
// Change the branch that used to go to AfterCallBB to branch to the first
// basic block of the inlined function.
//
Instruction *Br = OrigBB->getTerminator();
assert(Br && Br->getOpcode() == Instruction::Br &&
"splitBasicBlock broken!");
Br->setOperand(0, &*FirstNewBlock);
// Now that the function is correct, make it a little bit nicer. In
// particular, move the basic blocks inserted from the end of the function
// into the space made by splitting the source basic block.
Caller->getBasicBlockList().splice(AfterCallBB->getIterator(),
Caller->getBasicBlockList(), FirstNewBlock,
Caller->end());
// Handle all of the return instructions that we just cloned in, and eliminate
// any users of the original call/invoke instruction.
Type *RTy = CalledFunc->getReturnType();
PHINode *PHI = nullptr;
if (Returns.size() > 1) {
// The PHI node should go at the front of the new basic block to merge all
// possible incoming values.
if (!TheCall->use_empty()) {
PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
&AfterCallBB->front());
// Anything that used the result of the function call should now use the
// PHI node as their operand.
TheCall->replaceAllUsesWith(PHI);
}
// Loop over all of the return instructions adding entries to the PHI node
// as appropriate.
if (PHI) {
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
ReturnInst *RI = Returns[i];
assert(RI->getReturnValue()->getType() == PHI->getType() &&
"Ret value not consistent in function!");
PHI->addIncoming(RI->getReturnValue(), RI->getParent());
}
}
// Add a branch to the merge points and remove return instructions.
DebugLoc Loc;
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
ReturnInst *RI = Returns[i];
BranchInst* BI = BranchInst::Create(AfterCallBB, RI);
Loc = RI->getDebugLoc();
BI->setDebugLoc(Loc);
RI->eraseFromParent();
}
// We need to set the debug location to *somewhere* inside the
// inlined function. The line number may be nonsensical, but the
// instruction will at least be associated with the right
// function.
if (CreatedBranchToNormalDest)
CreatedBranchToNormalDest->setDebugLoc(Loc);
} else if (!Returns.empty()) {
// Otherwise, if there is exactly one return value, just replace anything
// using the return value of the call with the computed value.
if (!TheCall->use_empty()) {
if (TheCall == Returns[0]->getReturnValue())
TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
}
// Update PHI nodes that use the ReturnBB to use the AfterCallBB.
BasicBlock *ReturnBB = Returns[0]->getParent();
ReturnBB->replaceAllUsesWith(AfterCallBB);
// Splice the code from the return block into the block that it will return
// to, which contains the code that was after the call.
AfterCallBB->getInstList().splice(AfterCallBB->begin(),
ReturnBB->getInstList());
if (CreatedBranchToNormalDest)
CreatedBranchToNormalDest->setDebugLoc(Returns[0]->getDebugLoc());
// Delete the return instruction now and empty ReturnBB now.
Returns[0]->eraseFromParent();
ReturnBB->eraseFromParent();
} else if (!TheCall->use_empty()) {
// No returns, but something is using the return value of the call. Just
// nuke the result.
TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
}
// Since we are now done with the Call/Invoke, we can delete it.
TheCall->eraseFromParent();
// If we inlined any musttail calls and the original return is now
// unreachable, delete it. It can only contain a bitcast and ret.
if (InlinedMustTailCalls && pred_begin(AfterCallBB) == pred_end(AfterCallBB))
AfterCallBB->eraseFromParent();
// We should always be able to fold the entry block of the function into the
// single predecessor of the block...
assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);
// Splice the code entry block into calling block, right before the
// unconditional branch.
CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
OrigBB->getInstList().splice(Br->getIterator(), CalleeEntry->getInstList());
// Remove the unconditional branch.
OrigBB->getInstList().erase(Br);
// Now we can remove the CalleeEntry block, which is now empty.
Caller->getBasicBlockList().erase(CalleeEntry);
// If we inserted a phi node, check to see if it has a single value (e.g. all
// the entries are the same or undef). If so, remove the PHI so it doesn't
// block other optimizations.
if (PHI) {
AssumptionCache *AC =
IFI.GetAssumptionCache ? &(*IFI.GetAssumptionCache)(*Caller) : nullptr;
auto &DL = Caller->getParent()->getDataLayout();
if (Value *V = SimplifyInstruction(PHI, {DL, nullptr, nullptr, AC})) {
PHI->replaceAllUsesWith(V);
PHI->eraseFromParent();
}
}
return true;
}