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|
//===- bolt/Passes/StokeInfo.cpp ------------------------------------------===//
//
// 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 the StokeInfo class.
//
//===----------------------------------------------------------------------===//
#include "bolt/Passes/StokeInfo.h"
#include "bolt/Passes/BinaryFunctionCallGraph.h"
#include "bolt/Passes/DataflowInfoManager.h"
#include "llvm/Support/CommandLine.h"
#define DEBUG_TYPE "stoke"
using namespace llvm;
using namespace bolt;
namespace opts {
cl::OptionCategory StokeOptCategory("STOKE pass options");
static cl::opt<std::string>
StokeOutputDataFilename("stoke-out",
cl::desc("output data (.csv) for Stoke's use"),
cl::Optional,
cl::cat(StokeOptCategory));
}
namespace llvm {
namespace bolt {
void getRegNameFromBitVec(const BinaryContext &BC, const BitVector &RegV,
std::set<std::string> *NameVec = nullptr) {
for (int RegIdx : RegV.set_bits()) {
LLVM_DEBUG(dbgs() << BC.MRI->getName(RegIdx) << " ");
if (NameVec)
NameVec->insert(std::string(BC.MRI->getName(RegIdx)));
}
LLVM_DEBUG(dbgs() << "\n");
}
void StokeInfo::checkInstr(const BinaryFunction &BF, StokeFuncInfo &FuncInfo) {
MCPlusBuilder *MIB = BF.getBinaryContext().MIB.get();
BitVector RegV(NumRegs, false);
for (const BinaryBasicBlock *BB : BF.getLayout().blocks()) {
if (BB->empty())
continue;
for (const MCInst &It : *BB) {
if (MIB->isPseudo(It))
continue;
// skip function with exception handling yet
if (MIB->isEHLabel(It) || MIB->isInvoke(It)) {
FuncInfo.Omitted = true;
return;
}
// check if this function contains call instruction
if (MIB->isCall(It)) {
FuncInfo.HasCall = true;
const MCSymbol *TargetSymbol = MIB->getTargetSymbol(It);
// if it is an indirect call, skip
if (TargetSymbol == nullptr) {
FuncInfo.Omitted = true;
return;
}
}
// check if this function modify stack or heap
// TODO: more accurate analysis
bool IsPush = MIB->isPush(It);
bool IsRipAddr = MIB->hasPCRelOperand(It);
if (IsPush)
FuncInfo.StackOut = true;
if (MIB->isStore(It) && !IsPush && !IsRipAddr)
FuncInfo.HeapOut = true;
if (IsRipAddr)
FuncInfo.HasRipAddr = true;
} // end of for (auto &It : ...)
} // end of for (auto *BB : ...)
}
bool StokeInfo::checkFunction(BinaryFunction &BF, DataflowInfoManager &DInfo,
RegAnalysis &RA, StokeFuncInfo &FuncInfo) {
std::string Name = BF.getSymbol()->getName().str();
if (!BF.isSimple() || BF.isMultiEntry() || BF.empty())
return false;
outs() << " STOKE-INFO: analyzing function " << Name << "\n";
FuncInfo.FuncName = Name;
FuncInfo.Offset = BF.getFileOffset();
FuncInfo.Size = BF.getMaxSize();
FuncInfo.NumInstrs = BF.getNumNonPseudos();
FuncInfo.NumBlocks = BF.size();
// early stop for large functions
if (FuncInfo.NumInstrs > 500)
return false;
FuncInfo.IsLoopFree = BF.isLoopFree();
if (!FuncInfo.IsLoopFree) {
const BinaryLoopInfo &BLI = BF.getLoopInfo();
FuncInfo.NumLoops = BLI.OuterLoops;
FuncInfo.MaxLoopDepth = BLI.MaximumDepth;
}
FuncInfo.HotSize = BF.estimateHotSize();
FuncInfo.TotalSize = BF.estimateSize();
FuncInfo.Score = BF.getFunctionScore();
checkInstr(BF, FuncInfo);
// register analysis
BinaryBasicBlock &EntryBB = BF.front();
assert(EntryBB.isEntryPoint() && "Weird, this should be the entry block!");
MCInst *FirstNonPseudo = EntryBB.getFirstNonPseudoInstr();
if (!FirstNonPseudo)
return false;
LLVM_DEBUG(dbgs() << "\t [DefIn]\n\t ");
BitVector LiveInBV =
*(DInfo.getLivenessAnalysis().getStateAt(FirstNonPseudo));
LiveInBV &= DefaultDefInMask;
getRegNameFromBitVec(BF.getBinaryContext(), LiveInBV, &FuncInfo.DefIn);
LLVM_DEBUG(dbgs() << "\t [LiveOut]\n\t ");
BitVector LiveOutBV = RA.getFunctionClobberList(&BF);
LiveOutBV &= DefaultLiveOutMask;
getRegNameFromBitVec(BF.getBinaryContext(), LiveOutBV, &FuncInfo.LiveOut);
outs() << " STOKE-INFO: end function \n";
return true;
}
void StokeInfo::runOnFunctions(BinaryContext &BC) {
outs() << "STOKE-INFO: begin of stoke pass\n";
std::ofstream Outfile;
if (!opts::StokeOutputDataFilename.empty()) {
Outfile.open(opts::StokeOutputDataFilename);
} else {
errs() << "STOKE-INFO: output file is required\n";
return;
}
// check some context meta data
LLVM_DEBUG(dbgs() << "\tTarget: " << BC.TheTarget->getName() << "\n");
LLVM_DEBUG(dbgs() << "\tTripleName " << BC.TripleName << "\n");
LLVM_DEBUG(dbgs() << "\tgetNumRegs " << BC.MRI->getNumRegs() << "\n");
BinaryFunctionCallGraph CG = buildCallGraph(BC);
RegAnalysis RA(BC, &BC.getBinaryFunctions(), &CG);
NumRegs = BC.MRI->getNumRegs();
assert(NumRegs > 0 && "STOKE-INFO: the target register number is incorrect!");
DefaultDefInMask.resize(NumRegs, false);
DefaultLiveOutMask.resize(NumRegs, false);
BC.MIB->getDefaultDefIn(DefaultDefInMask);
BC.MIB->getDefaultLiveOut(DefaultLiveOutMask);
getRegNameFromBitVec(BC, DefaultDefInMask);
getRegNameFromBitVec(BC, DefaultLiveOutMask);
StokeFuncInfo FuncInfo;
// analyze all functions
FuncInfo.printCsvHeader(Outfile);
for (auto &BF : BC.getBinaryFunctions()) {
DataflowInfoManager DInfo(BF.second, &RA, nullptr);
FuncInfo.reset();
if (checkFunction(BF.second, DInfo, RA, FuncInfo))
FuncInfo.printData(Outfile);
}
outs() << "STOKE-INFO: end of stoke pass\n";
}
} // namespace bolt
} // namespace llvm
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