You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
110 lines
4.1 KiB
110 lines
4.1 KiB
//===-- IndirectCallPromotionAnalysis.cpp - Find promotion candidates ===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Helper methods for identifying profitable indirect call promotion
|
|
// candidates for an instruction when the indirect-call value profile metadata
|
|
// is available.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/Analysis/IndirectCallSiteVisitor.h"
|
|
#include "llvm/IR/CallSite.h"
|
|
#include "llvm/IR/DiagnosticInfo.h"
|
|
#include "llvm/IR/InstIterator.h"
|
|
#include "llvm/IR/InstVisitor.h"
|
|
#include "llvm/IR/Instructions.h"
|
|
#include "llvm/IR/IntrinsicInst.h"
|
|
#include "llvm/ProfileData/InstrProf.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include <string>
|
|
#include <utility>
|
|
#include <vector>
|
|
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "pgo-icall-prom-analysis"
|
|
|
|
// The minimum call count for the direct-call target to be considered as the
|
|
// promotion candidate.
|
|
static cl::opt<unsigned>
|
|
ICPCountThreshold("icp-count-threshold", cl::Hidden, cl::ZeroOrMore,
|
|
cl::init(1000),
|
|
cl::desc("The minimum count to the direct call target "
|
|
"for the promotion"));
|
|
|
|
// The percent threshold for the direct-call target (this call site vs the
|
|
// total call count) for it to be considered as the promotion target.
|
|
static cl::opt<unsigned>
|
|
ICPPercentThreshold("icp-percent-threshold", cl::init(33), cl::Hidden,
|
|
cl::ZeroOrMore,
|
|
cl::desc("The percentage threshold for the promotion"));
|
|
|
|
// Set the maximum number of targets to promote for a single indirect-call
|
|
// callsite.
|
|
static cl::opt<unsigned>
|
|
MaxNumPromotions("icp-max-prom", cl::init(2), cl::Hidden, cl::ZeroOrMore,
|
|
cl::desc("Max number of promotions for a single indirect "
|
|
"call callsite"));
|
|
|
|
ICallPromotionAnalysis::ICallPromotionAnalysis() {
|
|
ValueDataArray = llvm::make_unique<InstrProfValueData[]>(MaxNumPromotions);
|
|
}
|
|
|
|
bool ICallPromotionAnalysis::isPromotionProfitable(uint64_t Count,
|
|
uint64_t TotalCount) {
|
|
if (Count < ICPCountThreshold)
|
|
return false;
|
|
|
|
unsigned Percentage = (Count * 100) / TotalCount;
|
|
return (Percentage >= ICPPercentThreshold);
|
|
}
|
|
|
|
// Indirect-call promotion heuristic. The direct targets are sorted based on
|
|
// the count. Stop at the first target that is not promoted. Returns the
|
|
// number of candidates deemed profitable.
|
|
uint32_t ICallPromotionAnalysis::getProfitablePromotionCandidates(
|
|
const Instruction *Inst, uint32_t NumVals, uint64_t TotalCount) {
|
|
ArrayRef<InstrProfValueData> ValueDataRef(ValueDataArray.get(), NumVals);
|
|
|
|
DEBUG(dbgs() << " \nWork on callsite " << *Inst << " Num_targets: " << NumVals
|
|
<< "\n");
|
|
|
|
uint32_t I = 0;
|
|
for (; I < MaxNumPromotions && I < NumVals; I++) {
|
|
uint64_t Count = ValueDataRef[I].Count;
|
|
assert(Count <= TotalCount);
|
|
DEBUG(dbgs() << " Candidate " << I << " Count=" << Count
|
|
<< " Target_func: " << ValueDataRef[I].Value << "\n");
|
|
|
|
if (!isPromotionProfitable(Count, TotalCount)) {
|
|
DEBUG(dbgs() << " Not promote: Cold target.\n");
|
|
return I;
|
|
}
|
|
TotalCount -= Count;
|
|
}
|
|
return I;
|
|
}
|
|
|
|
ArrayRef<InstrProfValueData>
|
|
ICallPromotionAnalysis::getPromotionCandidatesForInstruction(
|
|
const Instruction *I, uint32_t &NumVals, uint64_t &TotalCount,
|
|
uint32_t &NumCandidates) {
|
|
bool Res =
|
|
getValueProfDataFromInst(*I, IPVK_IndirectCallTarget, MaxNumPromotions,
|
|
ValueDataArray.get(), NumVals, TotalCount);
|
|
if (!Res) {
|
|
NumCandidates = 0;
|
|
return ArrayRef<InstrProfValueData>();
|
|
}
|
|
NumCandidates = getProfitablePromotionCandidates(I, NumVals, TotalCount);
|
|
return ArrayRef<InstrProfValueData>(ValueDataArray.get(), NumVals);
|
|
}
|