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llvm-project/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp

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//===-- IndirectCallPromotion.cpp - Optimizations based on value profiling ===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the transformation that promotes indirect calls to
// conditional direct calls when the indirect-call value profile metadata is
// available.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
#include "llvm/Analysis/IndirectCallSiteVisitor.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.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/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/Pass.h"
#include "llvm/PassRegistry.h"
#include "llvm/PassSupport.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/PGOInstrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <cassert>
#include <cstdint>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "pgo-icall-prom"
STATISTIC(NumOfPGOICallPromotion, "Number of indirect call promotions.");
STATISTIC(NumOfPGOICallsites, "Number of indirect call candidate sites.");
STATISTIC(NumOfPGOMemOPOpt, "Number of memop intrinsics optimized.");
STATISTIC(NumOfPGOMemOPAnnotate, "Number of memop intrinsics annotated.");
// Command line option to disable indirect-call promotion with the default as
// false. This is for debug purpose.
static cl::opt<bool> DisableICP("disable-icp", cl::init(false), cl::Hidden,
cl::desc("Disable indirect call promotion"));
// Set the cutoff value for the promotion. If the value is other than 0, we
// stop the transformation once the total number of promotions equals the cutoff
// value.
// For debug use only.
static cl::opt<unsigned>
ICPCutOff("icp-cutoff", cl::init(0), cl::Hidden, cl::ZeroOrMore,
cl::desc("Max number of promotions for this compilaiton"));
// If ICPCSSkip is non zero, the first ICPCSSkip callsites will be skipped.
// For debug use only.
static cl::opt<unsigned>
ICPCSSkip("icp-csskip", cl::init(0), cl::Hidden, cl::ZeroOrMore,
cl::desc("Skip Callsite up to this number for this compilaiton"));
// Set if the pass is called in LTO optimization. The difference for LTO mode
// is the pass won't prefix the source module name to the internal linkage
// symbols.
static cl::opt<bool> ICPLTOMode("icp-lto", cl::init(false), cl::Hidden,
cl::desc("Run indirect-call promotion in LTO "
"mode"));
// Set if the pass is called in SamplePGO mode. The difference for SamplePGO
// mode is it will add prof metadatato the created direct call.
static cl::opt<bool>
ICPSamplePGOMode("icp-samplepgo", cl::init(false), cl::Hidden,
cl::desc("Run indirect-call promotion in SamplePGO mode"));
// If the option is set to true, only call instructions will be considered for
// transformation -- invoke instructions will be ignored.
static cl::opt<bool>
ICPCallOnly("icp-call-only", cl::init(false), cl::Hidden,
cl::desc("Run indirect-call promotion for call instructions "
"only"));
// If the option is set to true, only invoke instructions will be considered for
// transformation -- call instructions will be ignored.
static cl::opt<bool> ICPInvokeOnly("icp-invoke-only", cl::init(false),
cl::Hidden,
cl::desc("Run indirect-call promotion for "
"invoke instruction only"));
// Dump the function level IR if the transformation happened in this
// function. For debug use only.
static cl::opt<bool>
ICPDUMPAFTER("icp-dumpafter", cl::init(false), cl::Hidden,
cl::desc("Dump IR after transformation happens"));
// The minimum call count to optimize memory intrinsic calls.
static cl::opt<unsigned>
MemOPCountThreshold("pgo-memop-count-threshold", cl::Hidden, cl::ZeroOrMore,
cl::init(1000),
cl::desc("The minimum count to optimize memory "
"intrinsic calls"));
// Command line option to disable memory intrinsic optimization. The default is
// false. This is for debug purpose.
static cl::opt<bool> DisableMemOPOPT("disable-memop-opt", cl::init(false),
cl::Hidden, cl::desc("Disable optimize"));
// The percent threshold to optimize memory intrinsic calls.
static cl::opt<unsigned>
MemOPPercentThreshold("pgo-memop-percent-threshold", cl::init(40),
cl::Hidden, cl::ZeroOrMore,
cl::desc("The percentage threshold for the "
"memory intrinsic calls optimization"));
// Maximum number of versions for optimizing memory intrinsic call.
static cl::opt<unsigned>
MemOPMaxVersion("pgo-memop-max-version", cl::init(3), cl::Hidden,
cl::ZeroOrMore,
cl::desc("The max version for the optimized memory "
" intrinsic calls"));
// Scale the counts from the annotation using the BB count value.
static cl::opt<bool>
MemOPScaleCount("pgo-memop-scale-count", cl::init(true), cl::Hidden,
cl::desc("Scale the memop size counts using the basic "
" block count value"));
// This option sets the rangge of precise profile memop sizes.
extern cl::opt<std::string> MemOPSizeRange;
// This option sets the value that groups large memop sizes
extern cl::opt<unsigned> MemOPSizeLarge;
namespace {
class PGOIndirectCallPromotionLegacyPass : public ModulePass {
public:
static char ID;
PGOIndirectCallPromotionLegacyPass(bool InLTO = false, bool SamplePGO = false)
: ModulePass(ID), InLTO(InLTO), SamplePGO(SamplePGO) {
initializePGOIndirectCallPromotionLegacyPassPass(
*PassRegistry::getPassRegistry());
}
StringRef getPassName() const override { return "PGOIndirectCallPromotion"; }
private:
bool runOnModule(Module &M) override;
// If this pass is called in LTO. We need to special handling the PGOFuncName
// for the static variables due to LTO's internalization.
bool InLTO;
// If this pass is called in SamplePGO. We need to add the prof metadata to
// the promoted direct call.
bool SamplePGO;
};
class PGOMemOPSizeOptLegacyPass : public FunctionPass {
public:
static char ID;
PGOMemOPSizeOptLegacyPass() : FunctionPass(ID) {
initializePGOMemOPSizeOptLegacyPassPass(*PassRegistry::getPassRegistry());
}
StringRef getPassName() const override { return "PGOMemOPSize"; }
private:
bool runOnFunction(Function &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<BlockFrequencyInfoWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
}
};
} // end anonymous namespace
char PGOIndirectCallPromotionLegacyPass::ID = 0;
INITIALIZE_PASS(PGOIndirectCallPromotionLegacyPass, "pgo-icall-prom",
"Use PGO instrumentation profile to promote indirect calls to "
"direct calls.",
false, false)
ModulePass *llvm::createPGOIndirectCallPromotionLegacyPass(bool InLTO,
bool SamplePGO) {
return new PGOIndirectCallPromotionLegacyPass(InLTO, SamplePGO);
}
char PGOMemOPSizeOptLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(PGOMemOPSizeOptLegacyPass, "pgo-memop-opt",
"Optimize memory intrinsic using its size value profile",
false, false)
INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_END(PGOMemOPSizeOptLegacyPass, "pgo-memop-opt",
"Optimize memory intrinsic using its size value profile",
false, false)
FunctionPass *llvm::createPGOMemOPSizeOptLegacyPass() {
return new PGOMemOPSizeOptLegacyPass();
}
namespace {
// The class for main data structure to promote indirect calls to conditional
// direct calls.
class ICallPromotionFunc {
private:
Function &F;
Module *M;
// Symtab that maps indirect call profile values to function names and
// defines.
InstrProfSymtab *Symtab;
bool SamplePGO;
// Test if we can legally promote this direct-call of Target.
bool isPromotionLegal(Instruction *Inst, uint64_t Target, Function *&F,
const char **Reason = nullptr);
// A struct that records the direct target and it's call count.
struct PromotionCandidate {
Function *TargetFunction;
uint64_t Count;
PromotionCandidate(Function *F, uint64_t C) : TargetFunction(F), Count(C) {}
};
// Check if the indirect-call call site should be promoted. Return the number
// of promotions. Inst is the candidate indirect call, ValueDataRef
// contains the array of value profile data for profiled targets,
// TotalCount is the total profiled count of call executions, and
// NumCandidates is the number of candidate entries in ValueDataRef.
std::vector<PromotionCandidate> getPromotionCandidatesForCallSite(
Instruction *Inst, const ArrayRef<InstrProfValueData> &ValueDataRef,
uint64_t TotalCount, uint32_t NumCandidates);
// Promote a list of targets for one indirect-call callsite. Return
// the number of promotions.
uint32_t tryToPromote(Instruction *Inst,
const std::vector<PromotionCandidate> &Candidates,
uint64_t &TotalCount);
// Noncopyable
ICallPromotionFunc(const ICallPromotionFunc &other) = delete;
ICallPromotionFunc &operator=(const ICallPromotionFunc &other) = delete;
public:
ICallPromotionFunc(Function &Func, Module *Modu, InstrProfSymtab *Symtab,
bool SamplePGO)
: F(Func), M(Modu), Symtab(Symtab), SamplePGO(SamplePGO) {}
bool processFunction();
};
} // end anonymous namespace
bool llvm::isLegalToPromote(Instruction *Inst, Function *F,
const char **Reason) {
// Check the return type.
Type *CallRetType = Inst->getType();
if (!CallRetType->isVoidTy()) {
Type *FuncRetType = F->getReturnType();
if (FuncRetType != CallRetType &&
!CastInst::isBitCastable(FuncRetType, CallRetType)) {
if (Reason)
*Reason = "Return type mismatch";
return false;
}
}
// Check if the arguments are compatible with the parameters
FunctionType *DirectCalleeType = F->getFunctionType();
unsigned ParamNum = DirectCalleeType->getFunctionNumParams();
CallSite CS(Inst);
unsigned ArgNum = CS.arg_size();
if (ParamNum != ArgNum && !DirectCalleeType->isVarArg()) {
if (Reason)
*Reason = "The number of arguments mismatch";
return false;
}
for (unsigned I = 0; I < ParamNum; ++I) {
Type *PTy = DirectCalleeType->getFunctionParamType(I);
Type *ATy = CS.getArgument(I)->getType();
if (PTy == ATy)
continue;
if (!CastInst::castIsValid(Instruction::BitCast, CS.getArgument(I), PTy)) {
if (Reason)
*Reason = "Argument type mismatch";
return false;
}
}
DEBUG(dbgs() << " #" << NumOfPGOICallPromotion << " Promote the icall to "
<< F->getName() << "\n");
return true;
}
bool ICallPromotionFunc::isPromotionLegal(Instruction *Inst, uint64_t Target,
Function *&TargetFunction,
const char **Reason) {
TargetFunction = Symtab->getFunction(Target);
if (TargetFunction == nullptr) {
*Reason = "Cannot find the target";
return false;
}
return isLegalToPromote(Inst, TargetFunction, Reason);
}
// Indirect-call promotion heuristic. The direct targets are sorted based on
// the count. Stop at the first target that is not promoted.
std::vector<ICallPromotionFunc::PromotionCandidate>
ICallPromotionFunc::getPromotionCandidatesForCallSite(
Instruction *Inst, const ArrayRef<InstrProfValueData> &ValueDataRef,
uint64_t TotalCount, uint32_t NumCandidates) {
std::vector<PromotionCandidate> Ret;
DEBUG(dbgs() << " \nWork on callsite #" << NumOfPGOICallsites << *Inst
<< " Num_targets: " << ValueDataRef.size()
<< " Num_candidates: " << NumCandidates << "\n");
NumOfPGOICallsites++;
if (ICPCSSkip != 0 && NumOfPGOICallsites <= ICPCSSkip) {
DEBUG(dbgs() << " Skip: User options.\n");
return Ret;
}
for (uint32_t I = 0; I < NumCandidates; I++) {
uint64_t Count = ValueDataRef[I].Count;
assert(Count <= TotalCount);
uint64_t Target = ValueDataRef[I].Value;
DEBUG(dbgs() << " Candidate " << I << " Count=" << Count
<< " Target_func: " << Target << "\n");
if (ICPInvokeOnly && dyn_cast<CallInst>(Inst)) {
DEBUG(dbgs() << " Not promote: User options.\n");
break;
}
if (ICPCallOnly && dyn_cast<InvokeInst>(Inst)) {
DEBUG(dbgs() << " Not promote: User option.\n");
break;
}
if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
DEBUG(dbgs() << " Not promote: Cutoff reached.\n");
break;
}
Function *TargetFunction = nullptr;
const char *Reason = nullptr;
if (!isPromotionLegal(Inst, Target, TargetFunction, &Reason)) {
StringRef TargetFuncName = Symtab->getFuncName(Target);
DEBUG(dbgs() << " Not promote: " << Reason << "\n");
emitOptimizationRemarkMissed(
F.getContext(), "pgo-icall-prom", F, Inst->getDebugLoc(),
Twine("Cannot promote indirect call to ") +
(TargetFuncName.empty() ? Twine(Target) : Twine(TargetFuncName)) +
Twine(" with count of ") + Twine(Count) + ": " + Reason);
break;
}
Ret.push_back(PromotionCandidate(TargetFunction, Count));
TotalCount -= Count;
}
return Ret;
}
// Create a diamond structure for If_Then_Else. Also update the profile
// count. Do the fix-up for the invoke instruction.
static void createIfThenElse(Instruction *Inst, Function *DirectCallee,
uint64_t Count, uint64_t TotalCount,
BasicBlock **DirectCallBB,
BasicBlock **IndirectCallBB,
BasicBlock **MergeBB) {
CallSite CS(Inst);
Value *OrigCallee = CS.getCalledValue();
IRBuilder<> BBBuilder(Inst);
LLVMContext &Ctx = Inst->getContext();
Value *BCI1 =
BBBuilder.CreateBitCast(OrigCallee, Type::getInt8PtrTy(Ctx), "");
Value *BCI2 =
BBBuilder.CreateBitCast(DirectCallee, Type::getInt8PtrTy(Ctx), "");
Value *PtrCmp = BBBuilder.CreateICmpEQ(BCI1, BCI2, "");
uint64_t ElseCount = TotalCount - Count;
uint64_t MaxCount = (Count >= ElseCount ? Count : ElseCount);
uint64_t Scale = calculateCountScale(MaxCount);
MDBuilder MDB(Inst->getContext());
MDNode *BranchWeights = MDB.createBranchWeights(
scaleBranchCount(Count, Scale), scaleBranchCount(ElseCount, Scale));
TerminatorInst *ThenTerm, *ElseTerm;
SplitBlockAndInsertIfThenElse(PtrCmp, Inst, &ThenTerm, &ElseTerm,
BranchWeights);
*DirectCallBB = ThenTerm->getParent();
(*DirectCallBB)->setName("if.true.direct_targ");
*IndirectCallBB = ElseTerm->getParent();
(*IndirectCallBB)->setName("if.false.orig_indirect");
*MergeBB = Inst->getParent();
(*MergeBB)->setName("if.end.icp");
// Special handing of Invoke instructions.
InvokeInst *II = dyn_cast<InvokeInst>(Inst);
if (!II)
return;
// We don't need branch instructions for invoke.
ThenTerm->eraseFromParent();
ElseTerm->eraseFromParent();
// Add jump from Merge BB to the NormalDest. This is needed for the newly
// created direct invoke stmt -- as its NormalDst will be fixed up to MergeBB.
BranchInst::Create(II->getNormalDest(), *MergeBB);
}
// Find the PHI in BB that have the CallResult as the operand.
static bool getCallRetPHINode(BasicBlock *BB, Instruction *Inst) {
BasicBlock *From = Inst->getParent();
for (auto &I : *BB) {
PHINode *PHI = dyn_cast<PHINode>(&I);
if (!PHI)
continue;
int IX = PHI->getBasicBlockIndex(From);
if (IX == -1)
continue;
Value *V = PHI->getIncomingValue(IX);
if (dyn_cast<Instruction>(V) == Inst)
return true;
}
return false;
}
// This method fixes up PHI nodes in BB where BB is the UnwindDest of an
// invoke instruction. In BB, there may be PHIs with incoming block being
// OrigBB (the MergeBB after if-then-else splitting). After moving the invoke
// instructions to its own BB, OrigBB is no longer the predecessor block of BB.
// Instead two new predecessors are added: IndirectCallBB and DirectCallBB,
// so the PHI node's incoming BBs need to be fixed up accordingly.
static void fixupPHINodeForUnwind(Instruction *Inst, BasicBlock *BB,
BasicBlock *OrigBB,
BasicBlock *IndirectCallBB,
BasicBlock *DirectCallBB) {
for (auto &I : *BB) {
PHINode *PHI = dyn_cast<PHINode>(&I);
if (!PHI)
continue;
int IX = PHI->getBasicBlockIndex(OrigBB);
if (IX == -1)
continue;
Value *V = PHI->getIncomingValue(IX);
PHI->addIncoming(V, IndirectCallBB);
PHI->setIncomingBlock(IX, DirectCallBB);
}
}
// This method fixes up PHI nodes in BB where BB is the NormalDest of an
// invoke instruction. In BB, there may be PHIs with incoming block being
// OrigBB (the MergeBB after if-then-else splitting). After moving the invoke
// instructions to its own BB, a new incoming edge will be added to the original
// NormalDstBB from the IndirectCallBB.
static void fixupPHINodeForNormalDest(Instruction *Inst, BasicBlock *BB,
BasicBlock *OrigBB,
BasicBlock *IndirectCallBB,
Instruction *NewInst) {
for (auto &I : *BB) {
PHINode *PHI = dyn_cast<PHINode>(&I);
if (!PHI)
continue;
int IX = PHI->getBasicBlockIndex(OrigBB);
if (IX == -1)
continue;
Value *V = PHI->getIncomingValue(IX);
if (dyn_cast<Instruction>(V) == Inst) {
PHI->setIncomingBlock(IX, IndirectCallBB);
PHI->addIncoming(NewInst, OrigBB);
continue;
}
PHI->addIncoming(V, IndirectCallBB);
}
}
// Add a bitcast instruction to the direct-call return value if needed.
static Instruction *insertCallRetCast(const Instruction *Inst,
Instruction *DirectCallInst,
Function *DirectCallee) {
if (Inst->getType()->isVoidTy())
return DirectCallInst;
Type *CallRetType = Inst->getType();
Type *FuncRetType = DirectCallee->getReturnType();
if (FuncRetType == CallRetType)
return DirectCallInst;
BasicBlock *InsertionBB;
if (CallInst *CI = dyn_cast<CallInst>(DirectCallInst))
InsertionBB = CI->getParent();
else
InsertionBB = (dyn_cast<InvokeInst>(DirectCallInst))->getNormalDest();
return (new BitCastInst(DirectCallInst, CallRetType, "",
InsertionBB->getTerminator()));
}
// Create a DirectCall instruction in the DirectCallBB.
// Parameter Inst is the indirect-call (invoke) instruction.
// DirectCallee is the decl of the direct-call (invoke) target.
// DirecallBB is the BB that the direct-call (invoke) instruction is inserted.
// MergeBB is the bottom BB of the if-then-else-diamond after the
// transformation. For invoke instruction, the edges from DirectCallBB and
// IndirectCallBB to MergeBB are removed before this call (during
// createIfThenElse).
static Instruction *createDirectCallInst(const Instruction *Inst,
Function *DirectCallee,
BasicBlock *DirectCallBB,
BasicBlock *MergeBB) {
Instruction *NewInst = Inst->clone();
if (CallInst *CI = dyn_cast<CallInst>(NewInst)) {
CI->setCalledFunction(DirectCallee);
CI->mutateFunctionType(DirectCallee->getFunctionType());
} else {
// Must be an invoke instruction. Direct invoke's normal destination is
// fixed up to MergeBB. MergeBB is the place where return cast is inserted.
// Also since IndirectCallBB does not have an edge to MergeBB, there is no
// need to insert new PHIs into MergeBB.
InvokeInst *II = dyn_cast<InvokeInst>(NewInst);
assert(II);
II->setCalledFunction(DirectCallee);
II->mutateFunctionType(DirectCallee->getFunctionType());
II->setNormalDest(MergeBB);
}
DirectCallBB->getInstList().insert(DirectCallBB->getFirstInsertionPt(),
NewInst);
// Clear the value profile data.
NewInst->setMetadata(LLVMContext::MD_prof, nullptr);
CallSite NewCS(NewInst);
FunctionType *DirectCalleeType = DirectCallee->getFunctionType();
unsigned ParamNum = DirectCalleeType->getFunctionNumParams();
for (unsigned I = 0; I < ParamNum; ++I) {
Type *ATy = NewCS.getArgument(I)->getType();
Type *PTy = DirectCalleeType->getParamType(I);
if (ATy != PTy) {
BitCastInst *BI = new BitCastInst(NewCS.getArgument(I), PTy, "", NewInst);
NewCS.setArgument(I, BI);
}
}
return insertCallRetCast(Inst, NewInst, DirectCallee);
}
// Create a PHI to unify the return values of calls.
static void insertCallRetPHI(Instruction *Inst, Instruction *CallResult,
Function *DirectCallee) {
if (Inst->getType()->isVoidTy())
return;
BasicBlock *RetValBB = CallResult->getParent();
BasicBlock *PHIBB;
if (InvokeInst *II = dyn_cast<InvokeInst>(CallResult))
RetValBB = II->getNormalDest();
PHIBB = RetValBB->getSingleSuccessor();
if (getCallRetPHINode(PHIBB, Inst))
return;
PHINode *CallRetPHI = PHINode::Create(Inst->getType(), 0);
PHIBB->getInstList().push_front(CallRetPHI);
Inst->replaceAllUsesWith(CallRetPHI);
CallRetPHI->addIncoming(Inst, Inst->getParent());
CallRetPHI->addIncoming(CallResult, RetValBB);
}
// This function does the actual indirect-call promotion transformation:
// For an indirect-call like:
// Ret = (*Foo)(Args);
// It transforms to:
// if (Foo == DirectCallee)
// Ret1 = DirectCallee(Args);
// else
// Ret2 = (*Foo)(Args);
// Ret = phi(Ret1, Ret2);
// It adds type casts for the args do not match the parameters and the return
// value. Branch weights metadata also updated.
// If \p AttachProfToDirectCall is true, a prof metadata is attached to the
// new direct call to contain \p Count. This is used by SamplePGO inliner to
// check callsite hotness.
// Returns the promoted direct call instruction.
Instruction *llvm::promoteIndirectCall(Instruction *Inst,
Function *DirectCallee, uint64_t Count,
uint64_t TotalCount,
bool AttachProfToDirectCall) {
assert(DirectCallee != nullptr);
BasicBlock *BB = Inst->getParent();
// Just to suppress the non-debug build warning.
(void)BB;
DEBUG(dbgs() << "\n\n== Basic Block Before ==\n");
DEBUG(dbgs() << *BB << "\n");
BasicBlock *DirectCallBB, *IndirectCallBB, *MergeBB;
createIfThenElse(Inst, DirectCallee, Count, TotalCount, &DirectCallBB,
&IndirectCallBB, &MergeBB);
Instruction *NewInst =
createDirectCallInst(Inst, DirectCallee, DirectCallBB, MergeBB);
if (AttachProfToDirectCall) {
SmallVector<uint32_t, 1> Weights;
Weights.push_back(Count);
MDBuilder MDB(NewInst->getContext());
dyn_cast<Instruction>(NewInst->stripPointerCasts())
->setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
}
// Move Inst from MergeBB to IndirectCallBB.
Inst->removeFromParent();
IndirectCallBB->getInstList().insert(IndirectCallBB->getFirstInsertionPt(),
Inst);
if (InvokeInst *II = dyn_cast<InvokeInst>(Inst)) {
// At this point, the original indirect invoke instruction has the original
// UnwindDest and NormalDest. For the direct invoke instruction, the
// NormalDest points to MergeBB, and MergeBB jumps to the original
// NormalDest. MergeBB might have a new bitcast instruction for the return
// value. The PHIs are with the original NormalDest. Since we now have two
// incoming edges to NormalDest and UnwindDest, we have to do some fixups.
//
// UnwindDest will not use the return value. So pass nullptr here.
fixupPHINodeForUnwind(Inst, II->getUnwindDest(), MergeBB, IndirectCallBB,
DirectCallBB);
// We don't need to update the operand from NormalDest for DirectCallBB.
// Pass nullptr here.
fixupPHINodeForNormalDest(Inst, II->getNormalDest(), MergeBB,
IndirectCallBB, NewInst);
}
insertCallRetPHI(Inst, NewInst, DirectCallee);
DEBUG(dbgs() << "\n== Basic Blocks After ==\n");
DEBUG(dbgs() << *BB << *DirectCallBB << *IndirectCallBB << *MergeBB << "\n");
emitOptimizationRemark(
BB->getContext(), "pgo-icall-prom", *BB->getParent(), Inst->getDebugLoc(),
Twine("Promote indirect call to ") + DirectCallee->getName() +
" with count " + Twine(Count) + " out of " + Twine(TotalCount));
return NewInst;
}
// Promote indirect-call to conditional direct-call for one callsite.
uint32_t ICallPromotionFunc::tryToPromote(
Instruction *Inst, const std::vector<PromotionCandidate> &Candidates,
uint64_t &TotalCount) {
uint32_t NumPromoted = 0;
for (auto &C : Candidates) {
uint64_t Count = C.Count;
promoteIndirectCall(Inst, C.TargetFunction, Count, TotalCount, SamplePGO);
assert(TotalCount >= Count);
TotalCount -= Count;
NumOfPGOICallPromotion++;
NumPromoted++;
}
return NumPromoted;
}
// Traverse all the indirect-call callsite and get the value profile
// annotation to perform indirect-call promotion.
bool ICallPromotionFunc::processFunction() {
bool Changed = false;
ICallPromotionAnalysis ICallAnalysis;
for (auto &I : findIndirectCallSites(F)) {
uint32_t NumVals, NumCandidates;
uint64_t TotalCount;
auto ICallProfDataRef = ICallAnalysis.getPromotionCandidatesForInstruction(
I, NumVals, TotalCount, NumCandidates);
if (!NumCandidates)
continue;
auto PromotionCandidates = getPromotionCandidatesForCallSite(
I, ICallProfDataRef, TotalCount, NumCandidates);
uint32_t NumPromoted = tryToPromote(I, PromotionCandidates, TotalCount);
if (NumPromoted == 0)
continue;
Changed = true;
// Adjust the MD.prof metadata. First delete the old one.
I->setMetadata(LLVMContext::MD_prof, nullptr);
// If all promoted, we don't need the MD.prof metadata.
if (TotalCount == 0 || NumPromoted == NumVals)
continue;
// Otherwise we need update with the un-promoted records back.
annotateValueSite(*M, *I, ICallProfDataRef.slice(NumPromoted), TotalCount,
IPVK_IndirectCallTarget, NumCandidates);
}
return Changed;
}
// A wrapper function that does the actual work.
static bool promoteIndirectCalls(Module &M, bool InLTO, bool SamplePGO) {
if (DisableICP)
return false;
InstrProfSymtab Symtab;
Symtab.create(M, InLTO);
bool Changed = false;
for (auto &F : M) {
if (F.isDeclaration())
continue;
if (F.hasFnAttribute(Attribute::OptimizeNone))
continue;
ICallPromotionFunc ICallPromotion(F, &M, &Symtab, SamplePGO);
bool FuncChanged = ICallPromotion.processFunction();
if (ICPDUMPAFTER && FuncChanged) {
DEBUG(dbgs() << "\n== IR Dump After =="; F.print(dbgs()));
DEBUG(dbgs() << "\n");
}
Changed |= FuncChanged;
if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
DEBUG(dbgs() << " Stop: Cutoff reached.\n");
break;
}
}
return Changed;
}
bool PGOIndirectCallPromotionLegacyPass::runOnModule(Module &M) {
// Command-line option has the priority for InLTO.
return promoteIndirectCalls(M, InLTO | ICPLTOMode,
SamplePGO | ICPSamplePGOMode);
}
PreservedAnalyses PGOIndirectCallPromotion::run(Module &M,
ModuleAnalysisManager &AM) {
if (!promoteIndirectCalls(M, InLTO | ICPLTOMode,
SamplePGO | ICPSamplePGOMode))
return PreservedAnalyses::all();
return PreservedAnalyses::none();
}
namespace {
class MemOPSizeOpt : public InstVisitor<MemOPSizeOpt> {
public:
MemOPSizeOpt(Function &Func, BlockFrequencyInfo &BFI)
: Func(Func), BFI(BFI), Changed(false) {
ValueDataArray =
llvm::make_unique<InstrProfValueData[]>(MemOPMaxVersion + 2);
// Get the MemOPSize range information from option MemOPSizeRange,
getMemOPSizeRangeFromOption(MemOPSizeRange, PreciseRangeStart,
PreciseRangeLast);
}
bool isChanged() const { return Changed; }
void perform() {
WorkList.clear();
visit(Func);
for (auto &MI : WorkList) {
++NumOfPGOMemOPAnnotate;
if (perform(MI)) {
Changed = true;
++NumOfPGOMemOPOpt;
DEBUG(dbgs() << "MemOP calls: " << MI->getCalledFunction()->getName()
<< "is Transformed.\n");
}
}
}
void visitMemIntrinsic(MemIntrinsic &MI) {
Value *Length = MI.getLength();
// Not perform on constant length calls.
if (dyn_cast<ConstantInt>(Length))
return;
WorkList.push_back(&MI);
}
private:
Function &Func;
BlockFrequencyInfo &BFI;
bool Changed;
std::vector<MemIntrinsic *> WorkList;
// Start of the previse range.
int64_t PreciseRangeStart;
// Last value of the previse range.
int64_t PreciseRangeLast;
// The space to read the profile annotation.
std::unique_ptr<InstrProfValueData[]> ValueDataArray;
bool perform(MemIntrinsic *MI);
// This kind shows which group the value falls in. For PreciseValue, we have
// the profile count for that value. LargeGroup groups the values that are in
// range [LargeValue, +inf). NonLargeGroup groups the rest of values.
enum MemOPSizeKind { PreciseValue, NonLargeGroup, LargeGroup };
MemOPSizeKind getMemOPSizeKind(int64_t Value) const {
if (Value == MemOPSizeLarge && MemOPSizeLarge != 0)
return LargeGroup;
if (Value == PreciseRangeLast + 1)
return NonLargeGroup;
return PreciseValue;
}
};
static const char *getMIName(const MemIntrinsic *MI) {
switch (MI->getIntrinsicID()) {
case Intrinsic::memcpy:
return "memcpy";
case Intrinsic::memmove:
return "memmove";
case Intrinsic::memset:
return "memset";
default:
return "unknown";
}
}
static bool isProfitable(uint64_t Count, uint64_t TotalCount) {
assert(Count <= TotalCount);
if (Count < MemOPCountThreshold)
return false;
if (Count < TotalCount * MemOPPercentThreshold / 100)
return false;
return true;
}
static inline uint64_t getScaledCount(uint64_t Count, uint64_t Num,
uint64_t Denom) {
if (!MemOPScaleCount)
return Count;
bool Overflowed;
uint64_t ScaleCount = SaturatingMultiply(Count, Num, &Overflowed);
return ScaleCount / Denom;
}
bool MemOPSizeOpt::perform(MemIntrinsic *MI) {
assert(MI);
if (MI->getIntrinsicID() == Intrinsic::memmove)
return false;
uint32_t NumVals, MaxNumPromotions = MemOPMaxVersion + 2;
uint64_t TotalCount;
if (!getValueProfDataFromInst(*MI, IPVK_MemOPSize, MaxNumPromotions,
ValueDataArray.get(), NumVals, TotalCount))
return false;
uint64_t ActualCount = TotalCount;
uint64_t SavedTotalCount = TotalCount;
if (MemOPScaleCount) {
auto BBEdgeCount = BFI.getBlockProfileCount(MI->getParent());
if (!BBEdgeCount)
return false;
ActualCount = *BBEdgeCount;
}
if (ActualCount < MemOPCountThreshold)
return false;
ArrayRef<InstrProfValueData> VDs(ValueDataArray.get(), NumVals);
TotalCount = ActualCount;
if (MemOPScaleCount)
DEBUG(dbgs() << "Scale counts: numberator = " << ActualCount
<< " denominator = " << SavedTotalCount << "\n");
// Keeping track of the count of the default case:
uint64_t RemainCount = TotalCount;
SmallVector<uint64_t, 16> SizeIds;
SmallVector<uint64_t, 16> CaseCounts;
uint64_t MaxCount = 0;
unsigned Version = 0;
// Default case is in the front -- save the slot here.
CaseCounts.push_back(0);
for (auto &VD : VDs) {
int64_t V = VD.Value;
uint64_t C = VD.Count;
if (MemOPScaleCount)
C = getScaledCount(C, ActualCount, SavedTotalCount);
// Only care precise value here.
if (getMemOPSizeKind(V) != PreciseValue)
continue;
// ValueCounts are sorted on the count. Break at the first un-profitable
// value.
if (!isProfitable(C, RemainCount))
break;
SizeIds.push_back(V);
CaseCounts.push_back(C);
if (C > MaxCount)
MaxCount = C;
assert(RemainCount >= C);
RemainCount -= C;
if (++Version > MemOPMaxVersion && MemOPMaxVersion != 0)
break;
}
if (Version == 0)
return false;
CaseCounts[0] = RemainCount;
if (RemainCount > MaxCount)
MaxCount = RemainCount;
uint64_t SumForOpt = TotalCount - RemainCount;
DEBUG(dbgs() << "Read one memory intrinsic profile: " << SumForOpt << " vs "
<< TotalCount << "\n");
DEBUG(
for (auto &VD
: VDs) { dbgs() << " (" << VD.Value << "," << VD.Count << ")\n"; });
DEBUG(dbgs() << "Optimize one memory intrinsic call to " << Version
<< " Versions\n");
// mem_op(..., size)
// ==>
// switch (size) {
// case s1:
// mem_op(..., s1);
// goto merge_bb;
// case s2:
// mem_op(..., s2);
// goto merge_bb;
// ...
// default:
// mem_op(..., size);
// goto merge_bb;
// }
// merge_bb:
BasicBlock *BB = MI->getParent();
DEBUG(dbgs() << "\n\n== Basic Block Before ==\n");
DEBUG(dbgs() << *BB << "\n");
BasicBlock *DefaultBB = SplitBlock(BB, MI);
BasicBlock::iterator It(*MI);
++It;
assert(It != DefaultBB->end());
BasicBlock *MergeBB = SplitBlock(DefaultBB, &(*It));
DefaultBB->setName("MemOP.Default");
MergeBB->setName("MemOP.Merge");
auto &Ctx = Func.getContext();
IRBuilder<> IRB(BB);
BB->getTerminator()->eraseFromParent();
Value *SizeVar = MI->getLength();
SwitchInst *SI = IRB.CreateSwitch(SizeVar, DefaultBB, SizeIds.size());
// Clear the value profile data.
MI->setMetadata(LLVMContext::MD_prof, nullptr);
DEBUG(dbgs() << "\n\n== Basic Block After==\n");
for (uint64_t SizeId : SizeIds) {
ConstantInt *CaseSizeId = ConstantInt::get(Type::getInt64Ty(Ctx), SizeId);
BasicBlock *CaseBB = BasicBlock::Create(
Ctx, Twine("MemOP.Case.") + Twine(SizeId), &Func, DefaultBB);
Instruction *NewInst = MI->clone();
// Fix the argument.
dyn_cast<MemIntrinsic>(NewInst)->setLength(CaseSizeId);
CaseBB->getInstList().push_back(NewInst);
IRBuilder<> IRBCase(CaseBB);
IRBCase.CreateBr(MergeBB);
SI->addCase(CaseSizeId, CaseBB);
DEBUG(dbgs() << *CaseBB << "\n");
}
setProfMetadata(Func.getParent(), SI, CaseCounts, MaxCount);
DEBUG(dbgs() << *BB << "\n");
DEBUG(dbgs() << *DefaultBB << "\n");
DEBUG(dbgs() << *MergeBB << "\n");
emitOptimizationRemark(Func.getContext(), "memop-opt", Func,
MI->getDebugLoc(),
Twine("optimize ") + getMIName(MI) + " with count " +
Twine(SumForOpt) + " out of " + Twine(TotalCount) +
" for " + Twine(Version) + " versions");
return true;
}
} // namespace
static bool PGOMemOPSizeOptImpl(Function &F, BlockFrequencyInfo &BFI) {
if (DisableMemOPOPT)
return false;
if (F.hasFnAttribute(Attribute::OptimizeForSize))
return false;
MemOPSizeOpt MemOPSizeOpt(F, BFI);
MemOPSizeOpt.perform();
return MemOPSizeOpt.isChanged();
}
bool PGOMemOPSizeOptLegacyPass::runOnFunction(Function &F) {
BlockFrequencyInfo &BFI =
getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
return PGOMemOPSizeOptImpl(F, BFI);
}
namespace llvm {
char &PGOMemOPSizeOptID = PGOMemOPSizeOptLegacyPass::ID;
PreservedAnalyses PGOMemOPSizeOpt::run(Function &F,
FunctionAnalysisManager &FAM) {
auto &BFI = FAM.getResult<BlockFrequencyAnalysis>(F);
bool Changed = PGOMemOPSizeOptImpl(F, BFI);
if (!Changed)
return PreservedAnalyses::all();
auto PA = PreservedAnalyses();
PA.preserve<GlobalsAA>();
return PA;
}
} // namespace llvm
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