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DataReader.cpp
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//===- bolt/Profile/DataReader.cpp - Perf data reader ---------------------===//
//
// 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 family of functions reads profile data written by the perf2bolt
// utility and stores it in memory for llvm-bolt consumption.
//
//===----------------------------------------------------------------------===//
#include "bolt/Profile/DataReader.h"
#include "bolt/Core/BinaryFunction.h"
#include "bolt/Passes/MCF.h"
#include "bolt/Utils/Utils.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Errc.h"
#undef DEBUG_TYPE
#define DEBUG_TYPE "bolt-prof"
using namespace llvm;
namespace opts {
extern cl::OptionCategory BoltCategory;
extern llvm::cl::opt<unsigned> Verbosity;
static cl::opt<bool>
DumpData("dump-data",
cl::desc("dump parsed bolt data for debugging"),
cl::Hidden,
cl::cat(BoltCategory));
} // namespace opts
namespace llvm {
namespace bolt {
namespace {
/// Return true if the function name can change across compilations.
bool hasVolatileName(const BinaryFunction &BF) {
for (const StringRef &Name : BF.getNames())
if (getLTOCommonName(Name))
return true;
return false;
}
/// Return standard escaped name of the function possibly renamed by BOLT.
std::string normalizeName(StringRef NameRef) {
// Strip "PG." prefix used for globalized locals.
NameRef = NameRef.starts_with("PG.") ? NameRef.substr(2) : NameRef;
return getEscapedName(NameRef);
}
} // anonymous namespace
raw_ostream &operator<<(raw_ostream &OS, const Location &Loc) {
if (Loc.IsSymbol) {
OS << Loc.Name;
if (Loc.Offset)
OS << "+" << Twine::utohexstr(Loc.Offset);
} else {
OS << Twine::utohexstr(Loc.Offset);
}
return OS;
}
void FuncBranchData::appendFrom(const FuncBranchData &FBD, uint64_t Offset) {
Data.insert(Data.end(), FBD.Data.begin(), FBD.Data.end());
for (auto I = Data.begin(), E = Data.end(); I != E; ++I) {
if (I->From.Name == FBD.Name) {
I->From.Name = this->Name;
I->From.Offset += Offset;
}
if (I->To.Name == FBD.Name) {
I->To.Name = this->Name;
I->To.Offset += Offset;
}
}
llvm::stable_sort(Data);
ExecutionCount += FBD.ExecutionCount;
for (auto I = FBD.EntryData.begin(), E = FBD.EntryData.end(); I != E; ++I) {
assert(I->To.Name == FBD.Name);
auto NewElmt = EntryData.insert(EntryData.end(), *I);
NewElmt->To.Name = this->Name;
NewElmt->To.Offset += Offset;
}
}
uint64_t FuncBranchData::getNumExecutedBranches() const {
uint64_t ExecutedBranches = 0;
for (const BranchInfo &BI : Data) {
int64_t BranchCount = BI.Branches;
assert(BranchCount >= 0 && "branch execution count should not be negative");
ExecutedBranches += BranchCount;
}
return ExecutedBranches;
}
void SampleInfo::mergeWith(const SampleInfo &SI) { Hits += SI.Hits; }
void SampleInfo::print(raw_ostream &OS) const {
OS << Loc.IsSymbol << " " << Loc.Name << " " << Twine::utohexstr(Loc.Offset)
<< " " << Hits << "\n";
}
uint64_t FuncSampleData::getSamples(uint64_t Start, uint64_t End) const {
assert(llvm::is_sorted(Data));
struct Compare {
bool operator()(const SampleInfo &SI, const uint64_t Val) const {
return SI.Loc.Offset < Val;
}
bool operator()(const uint64_t Val, const SampleInfo &SI) const {
return Val < SI.Loc.Offset;
}
};
uint64_t Result = 0;
for (auto I = llvm::lower_bound(Data, Start, Compare()),
E = llvm::lower_bound(Data, End, Compare());
I != E; ++I)
Result += I->Hits;
return Result;
}
void FuncSampleData::bumpCount(uint64_t Offset, uint64_t Count) {
auto Iter = Index.find(Offset);
if (Iter == Index.end()) {
Data.emplace_back(Location(true, Name, Offset), Count);
Index[Offset] = Data.size() - 1;
return;
}
SampleInfo &SI = Data[Iter->second];
SI.Hits += Count;
}
void FuncBranchData::bumpBranchCount(uint64_t OffsetFrom, uint64_t OffsetTo,
uint64_t Count, uint64_t Mispreds) {
auto Iter = IntraIndex[OffsetFrom].find(OffsetTo);
if (Iter == IntraIndex[OffsetFrom].end()) {
Data.emplace_back(Location(true, Name, OffsetFrom),
Location(true, Name, OffsetTo), Mispreds, Count);
IntraIndex[OffsetFrom][OffsetTo] = Data.size() - 1;
return;
}
BranchInfo &BI = Data[Iter->second];
BI.Branches += Count;
BI.Mispreds += Mispreds;
}
void FuncBranchData::bumpCallCount(uint64_t OffsetFrom, const Location &To,
uint64_t Count, uint64_t Mispreds) {
auto Iter = InterIndex[OffsetFrom].find(To);
if (Iter == InterIndex[OffsetFrom].end()) {
Data.emplace_back(Location(true, Name, OffsetFrom), To, Mispreds, Count);
InterIndex[OffsetFrom][To] = Data.size() - 1;
return;
}
BranchInfo &BI = Data[Iter->second];
BI.Branches += Count;
BI.Mispreds += Mispreds;
}
void FuncBranchData::bumpEntryCount(const Location &From, uint64_t OffsetTo,
uint64_t Count, uint64_t Mispreds) {
auto Iter = EntryIndex[OffsetTo].find(From);
if (Iter == EntryIndex[OffsetTo].end()) {
EntryData.emplace_back(From, Location(true, Name, OffsetTo), Mispreds,
Count);
EntryIndex[OffsetTo][From] = EntryData.size() - 1;
return;
}
BranchInfo &BI = EntryData[Iter->second];
BI.Branches += Count;
BI.Mispreds += Mispreds;
}
void BranchInfo::mergeWith(const BranchInfo &BI) {
Branches += BI.Branches;
Mispreds += BI.Mispreds;
}
void BranchInfo::print(raw_ostream &OS) const {
OS << From.IsSymbol << " " << From.Name << " "
<< Twine::utohexstr(From.Offset) << " " << To.IsSymbol << " " << To.Name
<< " " << Twine::utohexstr(To.Offset) << " " << Mispreds << " " << Branches
<< '\n';
}
ErrorOr<const BranchInfo &> FuncBranchData::getBranch(uint64_t From,
uint64_t To) const {
for (const BranchInfo &I : Data)
if (I.From.Offset == From && I.To.Offset == To && I.From.Name == I.To.Name)
return I;
return make_error_code(llvm::errc::invalid_argument);
}
ErrorOr<const BranchInfo &>
FuncBranchData::getDirectCallBranch(uint64_t From) const {
// Commented out because it can be expensive.
// assert(std::is_sorted(Data.begin(), Data.end()));
struct Compare {
bool operator()(const BranchInfo &BI, const uint64_t Val) const {
return BI.From.Offset < Val;
}
bool operator()(const uint64_t Val, const BranchInfo &BI) const {
return Val < BI.From.Offset;
}
};
auto Range = std::equal_range(Data.begin(), Data.end(), From, Compare());
for (const auto &RI : llvm::make_range(Range))
if (RI.From.Name != RI.To.Name)
return RI;
return make_error_code(llvm::errc::invalid_argument);
}
void MemInfo::print(raw_ostream &OS) const {
OS << (Offset.IsSymbol + 3) << " " << Offset.Name << " "
<< Twine::utohexstr(Offset.Offset) << " " << (Addr.IsSymbol + 3) << " "
<< Addr.Name << " " << Twine::utohexstr(Addr.Offset) << " " << Count
<< "\n";
}
void MemInfo::prettyPrint(raw_ostream &OS) const {
OS << "(PC: " << Offset << ", M: " << Addr << ", C: " << Count << ")";
}
void FuncMemData::update(const Location &Offset, const Location &Addr) {
auto Iter = EventIndex[Offset.Offset].find(Addr);
if (Iter == EventIndex[Offset.Offset].end()) {
Data.emplace_back(MemInfo(Offset, Addr, 1));
EventIndex[Offset.Offset][Addr] = Data.size() - 1;
return;
}
++Data[Iter->second].Count;
}
Error DataReader::preprocessProfile(BinaryContext &BC) {
if (std::error_code EC = parseInput())
return errorCodeToError(EC);
if (opts::DumpData)
dump();
if (collectedInBoltedBinary())
outs() << "BOLT-INFO: profile collection done on a binary already "
"processed by BOLT\n";
for (auto &BFI : BC.getBinaryFunctions()) {
BinaryFunction &Function = BFI.second;
if (FuncMemData *MemData = getMemDataForNames(Function.getNames())) {
setMemData(Function, MemData);
MemData->Used = true;
}
if (FuncBranchData *FuncData = getBranchDataForNames(Function.getNames())) {
setBranchData(Function, FuncData);
Function.ExecutionCount = FuncData->ExecutionCount;
FuncData->Used = true;
}
}
for (auto &BFI : BC.getBinaryFunctions()) {
BinaryFunction &Function = BFI.second;
matchProfileMemData(Function);
}
return Error::success();
}
Error DataReader::readProfilePreCFG(BinaryContext &BC) {
for (auto &BFI : BC.getBinaryFunctions()) {
BinaryFunction &Function = BFI.second;
FuncMemData *MemoryData = getMemData(Function);
if (!MemoryData)
continue;
for (MemInfo &MI : MemoryData->Data) {
const uint64_t Offset = MI.Offset.Offset;
auto II = Function.Instructions.find(Offset);
if (II == Function.Instructions.end()) {
// Ignore bad instruction address.
continue;
}
auto &MemAccessProfile =
BC.MIB->getOrCreateAnnotationAs<MemoryAccessProfile>(
II->second, "MemoryAccessProfile");
BinaryData *BD = nullptr;
if (MI.Addr.IsSymbol)
BD = BC.getBinaryDataByName(MI.Addr.Name);
MemAccessProfile.AddressAccessInfo.push_back(
{BD, MI.Addr.Offset, MI.Count});
auto NextII = std::next(II);
if (NextII == Function.Instructions.end())
MemAccessProfile.NextInstrOffset = Function.getSize();
else
MemAccessProfile.NextInstrOffset = II->first;
}
Function.HasMemoryProfile = true;
}
return Error::success();
}
Error DataReader::readProfile(BinaryContext &BC) {
for (auto &BFI : BC.getBinaryFunctions()) {
BinaryFunction &Function = BFI.second;
readProfile(Function);
}
uint64_t NumUnused = 0;
for (const auto &KV : NamesToBranches) {
const FuncBranchData &FBD = KV.second;
if (!FBD.Used)
++NumUnused;
}
BC.setNumUnusedProfiledObjects(NumUnused);
return Error::success();
}
std::error_code DataReader::parseInput() {
ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
MemoryBuffer::getFileOrSTDIN(Filename);
if (std::error_code EC = MB.getError()) {
Diag << "cannot open " << Filename << ": " << EC.message() << "\n";
return EC;
}
FileBuf = std::move(MB.get());
ParsingBuf = FileBuf->getBuffer();
if (std::error_code EC = parse())
return EC;
if (!ParsingBuf.empty())
Diag << "WARNING: invalid profile data detected at line " << Line
<< ". Possibly corrupted profile.\n";
buildLTONameMaps();
return std::error_code();
}
void DataReader::readProfile(BinaryFunction &BF) {
if (BF.empty())
return;
if (!hasLBR()) {
BF.ProfileFlags = BinaryFunction::PF_SAMPLE;
readSampleData(BF);
return;
}
BF.ProfileFlags = BinaryFunction::PF_LBR;
// Possibly assign/re-assign branch profile data.
matchProfileData(BF);
FuncBranchData *FBD = getBranchData(BF);
if (!FBD)
return;
// Assign basic block counts to function entry points. These only include
// counts for outside entries.
//
// There is a slight skew introduced here as branches originated from RETs
// may be accounted for in the execution count of an entry block if the last
// instruction in a predecessor fall-through block is a call. This situation
// should rarely happen because there are few multiple-entry functions.
for (const BranchInfo &BI : FBD->EntryData) {
BinaryBasicBlock *BB = BF.getBasicBlockAtOffset(BI.To.Offset);
if (BB && (BB->isEntryPoint() || BB->isLandingPad())) {
uint64_t Count = BB->getExecutionCount();
if (Count == BinaryBasicBlock::COUNT_NO_PROFILE)
Count = 0;
BB->setExecutionCount(Count + BI.Branches);
}
}
for (const BranchInfo &BI : FBD->Data) {
if (BI.From.Name != BI.To.Name)
continue;
if (!recordBranch(BF, BI.From.Offset, BI.To.Offset, BI.Branches,
BI.Mispreds)) {
LLVM_DEBUG(dbgs() << "bad branch : " << BI.From.Offset << " -> "
<< BI.To.Offset << '\n');
}
}
// Convert branch data into annotations.
convertBranchData(BF);
}
void DataReader::matchProfileData(BinaryFunction &BF) {
// This functionality is available for LBR-mode only
// TODO: Implement evaluateProfileData() for samples, checking whether
// sample addresses match instruction addresses in the function
if (!hasLBR())
return;
FuncBranchData *FBD = getBranchData(BF);
if (FBD) {
BF.ProfileMatchRatio = evaluateProfileData(BF, *FBD);
BF.RawBranchCount = FBD->getNumExecutedBranches();
if (BF.ProfileMatchRatio == 1.0f) {
if (fetchProfileForOtherEntryPoints(BF)) {
BF.ProfileMatchRatio = evaluateProfileData(BF, *FBD);
BF.ExecutionCount = FBD->ExecutionCount;
BF.RawBranchCount = FBD->getNumExecutedBranches();
}
return;
}
}
// Check if the function name can fluctuate between several compilations
// possibly triggered by minor unrelated code changes in the source code
// of the input binary.
if (!hasVolatileName(BF))
return;
// Check for a profile that matches with 100% confidence.
const std::vector<FuncBranchData *> AllBranchData =
getBranchDataForNamesRegex(BF.getNames());
for (FuncBranchData *NewBranchData : AllBranchData) {
// Prevent functions from sharing the same profile.
if (NewBranchData->Used)
continue;
if (evaluateProfileData(BF, *NewBranchData) != 1.0f)
continue;
if (FBD)
FBD->Used = false;
// Update function profile data with the new set.
setBranchData(BF, NewBranchData);
NewBranchData->Used = true;
BF.ExecutionCount = NewBranchData->ExecutionCount;
BF.ProfileMatchRatio = 1.0f;
break;
}
}
void DataReader::matchProfileMemData(BinaryFunction &BF) {
const std::vector<FuncMemData *> AllMemData =
getMemDataForNamesRegex(BF.getNames());
for (FuncMemData *NewMemData : AllMemData) {
// Prevent functions from sharing the same profile.
if (NewMemData->Used)
continue;
if (FuncMemData *MD = getMemData(BF))
MD->Used = false;
// Update function profile data with the new set.
setMemData(BF, NewMemData);
NewMemData->Used = true;
break;
}
}
bool DataReader::fetchProfileForOtherEntryPoints(BinaryFunction &BF) {
BinaryContext &BC = BF.getBinaryContext();
FuncBranchData *FBD = getBranchData(BF);
if (!FBD)
return false;
// Check if we are missing profiling data for secondary entry points
bool First = true;
bool Updated = false;
for (BinaryBasicBlock *BB : BF.BasicBlocks) {
if (First) {
First = false;
continue;
}
if (BB->isEntryPoint()) {
uint64_t EntryAddress = BB->getOffset() + BF.getAddress();
// Look for branch data associated with this entry point
if (BinaryData *BD = BC.getBinaryDataAtAddress(EntryAddress)) {
if (FuncBranchData *Data = getBranchDataForSymbols(BD->getSymbols())) {
FBD->appendFrom(*Data, BB->getOffset());
Data->Used = true;
Updated = true;
}
}
}
}
return Updated;
}
float DataReader::evaluateProfileData(BinaryFunction &BF,
const FuncBranchData &BranchData) const {
BinaryContext &BC = BF.getBinaryContext();
// Until we define a minimal profile, we consider an empty branch data to be
// a valid profile. It could happen to a function without branches when we
// still have an EntryData for the execution count.
if (BranchData.Data.empty())
return 1.0f;
uint64_t NumMatchedBranches = 0;
for (const BranchInfo &BI : BranchData.Data) {
bool IsValid = false;
if (BI.From.Name == BI.To.Name) {
// Try to record information with 0 count.
IsValid = recordBranch(BF, BI.From.Offset, BI.To.Offset, 0);
} else if (collectedInBoltedBinary()) {
// We can't check branch source for collections in bolted binaries because
// the source of the branch may be mapped to the first instruction in a BB
// instead of the original branch (which may not exist in the source bin).
IsValid = true;
} else {
// The branch has to originate from this function.
// Check for calls, tail calls, rets and indirect branches.
// When matching profiling info, we did not reach the stage
// when we identify tail calls, so they are still represented
// by regular branch instructions and we need isBranch() here.
MCInst *Instr = BF.getInstructionAtOffset(BI.From.Offset);
// If it's a prefix - skip it.
if (Instr && BC.MIB->isPrefix(*Instr))
Instr = BF.getInstructionAtOffset(BI.From.Offset + 1);
if (Instr && (BC.MIB->isCall(*Instr) || BC.MIB->isBranch(*Instr) ||
BC.MIB->isReturn(*Instr)))
IsValid = true;
}
if (IsValid) {
++NumMatchedBranches;
continue;
}
LLVM_DEBUG(dbgs() << "\tinvalid branch in " << BF << " : 0x"
<< Twine::utohexstr(BI.From.Offset) << " -> ";
if (BI.From.Name == BI.To.Name) dbgs()
<< "0x" << Twine::utohexstr(BI.To.Offset) << '\n';
else dbgs() << "<outbounds>\n";);
}
const float MatchRatio = (float)NumMatchedBranches / BranchData.Data.size();
if (opts::Verbosity >= 2 && NumMatchedBranches < BranchData.Data.size())
errs() << "BOLT-WARNING: profile branches match only "
<< format("%.1f%%", MatchRatio * 100.0f) << " ("
<< NumMatchedBranches << '/' << BranchData.Data.size()
<< ") for function " << BF << '\n';
return MatchRatio;
}
void DataReader::readSampleData(BinaryFunction &BF) {
FuncSampleData *SampleDataOrErr = getFuncSampleData(BF.getNames());
if (!SampleDataOrErr)
return;
// Basic samples mode territory (without LBR info)
// First step is to assign BB execution count based on samples from perf
BF.ProfileMatchRatio = 1.0f;
BF.removeTagsFromProfile();
bool NormalizeByInsnCount = usesEvent("cycles") || usesEvent("instructions");
bool NormalizeByCalls = usesEvent("branches");
static bool NagUser = true;
if (NagUser) {
outs()
<< "BOLT-INFO: operating with basic samples profiling data (no LBR).\n";
if (NormalizeByInsnCount)
outs() << "BOLT-INFO: normalizing samples by instruction count.\n";
else if (NormalizeByCalls)
outs() << "BOLT-INFO: normalizing samples by branches.\n";
NagUser = false;
}
uint64_t LastOffset = BF.getSize();
uint64_t TotalEntryCount = 0;
for (BinaryFunction::BasicBlockOffset &BBOffset :
llvm::reverse(BF.BasicBlockOffsets)) {
uint64_t CurOffset = BBOffset.first;
// Always work with samples multiplied by 1000 to avoid losing them if we
// later need to normalize numbers
uint64_t NumSamples =
SampleDataOrErr->getSamples(CurOffset, LastOffset) * 1000;
if (NormalizeByInsnCount && BBOffset.second->getNumNonPseudos()) {
NumSamples /= BBOffset.second->getNumNonPseudos();
} else if (NormalizeByCalls) {
uint32_t NumCalls = BBOffset.second->getNumCalls();
NumSamples /= NumCalls + 1;
}
BBOffset.second->setExecutionCount(NumSamples);
if (BBOffset.second->isEntryPoint())
TotalEntryCount += NumSamples;
LastOffset = CurOffset;
}
BF.ExecutionCount = TotalEntryCount;
}
void DataReader::convertBranchData(BinaryFunction &BF) const {
BinaryContext &BC = BF.getBinaryContext();
if (BF.empty())
return;
FuncBranchData *FBD = getBranchData(BF);
if (!FBD)
return;
// Profile information for calls.
//
// There are 3 cases that we annotate differently:
// 1) Conditional tail calls that could be mispredicted.
// 2) Indirect calls to multiple destinations with mispredictions.
// Before we validate CFG we have to handle indirect branches here too.
// 3) Regular direct calls. The count could be different from containing
// basic block count. Keep this data in case we find it useful.
//
for (BranchInfo &BI : FBD->Data) {
// Ignore internal branches.
if (BI.To.IsSymbol && BI.To.Name == BI.From.Name && BI.To.Offset != 0)
continue;
MCInst *Instr = BF.getInstructionAtOffset(BI.From.Offset);
if (!Instr ||
(!BC.MIB->isCall(*Instr) && !BC.MIB->isIndirectBranch(*Instr)))
continue;
auto setOrUpdateAnnotation = [&](StringRef Name, uint64_t Count) {
if (opts::Verbosity >= 1 && BC.MIB->hasAnnotation(*Instr, Name))
errs() << "BOLT-WARNING: duplicate " << Name << " info for offset 0x"
<< Twine::utohexstr(BI.From.Offset) << " in function " << BF
<< '\n';
auto &Value = BC.MIB->getOrCreateAnnotationAs<uint64_t>(*Instr, Name);
Value += Count;
};
if (BC.MIB->isIndirectCall(*Instr) || BC.MIB->isIndirectBranch(*Instr)) {
IndirectCallSiteProfile &CSP =
BC.MIB->getOrCreateAnnotationAs<IndirectCallSiteProfile>(
*Instr, "CallProfile");
MCSymbol *CalleeSymbol = nullptr;
if (BI.To.IsSymbol) {
if (BinaryData *BD = BC.getBinaryDataByName(BI.To.Name))
CalleeSymbol = BD->getSymbol();
}
CSP.emplace_back(CalleeSymbol, BI.Branches, BI.Mispreds);
} else if (BC.MIB->getConditionalTailCall(*Instr)) {
setOrUpdateAnnotation("CTCTakenCount", BI.Branches);
setOrUpdateAnnotation("CTCMispredCount", BI.Mispreds);
} else {
setOrUpdateAnnotation("Count", BI.Branches);
}
}
}
bool DataReader::recordBranch(BinaryFunction &BF, uint64_t From, uint64_t To,
uint64_t Count, uint64_t Mispreds) const {
BinaryContext &BC = BF.getBinaryContext();
BinaryBasicBlock *FromBB = BF.getBasicBlockContainingOffset(From);
const BinaryBasicBlock *ToBB = BF.getBasicBlockContainingOffset(To);
if (!FromBB || !ToBB) {
LLVM_DEBUG(dbgs() << "failed to get block for recorded branch\n");
return false;
}
// Could be bad LBR data; ignore the branch. In the case of data collected
// in binaries optimized by BOLT, a source BB may be mapped to two output
// BBs as a result of optimizations. In that case, a branch between these
// two will be recorded as a branch from A going to A in the source address
// space. Keep processing.
if (From == To)
return true;
// Return from a tail call.
if (FromBB->succ_size() == 0)
return true;
// Very rarely we will see ignored branches. Do a linear check.
for (std::pair<uint32_t, uint32_t> &Branch : BF.IgnoredBranches)
if (Branch ==
std::make_pair(static_cast<uint32_t>(From), static_cast<uint32_t>(To)))
return true;
bool OffsetMatches = !!(To == ToBB->getOffset());
if (!OffsetMatches) {
// Skip the nops to support old .fdata
uint64_t Offset = ToBB->getOffset();
for (const MCInst &Instr : *ToBB) {
if (!BC.MIB->isNoop(Instr))
break;
if (std::optional<uint32_t> Size = BC.MIB->getSize(Instr))
Offset += *Size;
}
if (To == Offset)
OffsetMatches = true;
}
if (!OffsetMatches) {
// "To" could be referring to nop instructions in between 2 basic blocks.
// While building the CFG we make sure these nops are attributed to the
// previous basic block, thus we check if the destination belongs to the
// gap past the last instruction.
const MCInst *LastInstr = ToBB->getLastNonPseudoInstr();
if (LastInstr) {
const uint32_t LastInstrOffset =
BC.MIB->getOffsetWithDefault(*LastInstr, 0);
// With old .fdata we are getting FT branches for "jcc,jmp" sequences.
if (To == LastInstrOffset && BC.MIB->isUnconditionalBranch(*LastInstr))
return true;
if (To <= LastInstrOffset) {
LLVM_DEBUG(dbgs() << "branch recorded into the middle of the block"
<< " in " << BF << " : " << From << " -> " << To
<< '\n');
return false;
}
}
// The real destination is the layout successor of the detected ToBB.
if (ToBB == BF.getLayout().block_back())
return false;
const BinaryBasicBlock *NextBB =
BF.getLayout().getBlock(ToBB->getIndex() + 1);
assert((NextBB && NextBB->getOffset() > ToBB->getOffset()) && "bad layout");
ToBB = NextBB;
}
// If there's no corresponding instruction for 'From', we have probably
// discarded it as a FT from __builtin_unreachable.
MCInst *FromInstruction = BF.getInstructionAtOffset(From);
if (!FromInstruction) {
// If the data was collected in a bolted binary, the From addresses may be
// translated to the first instruction of the source BB if BOLT inserted
// a new branch that did not exist in the source (we can't map it to the
// source instruction, so we map it to the first instr of source BB).
// We do not keep offsets for random instructions. So the check above will
// evaluate to true if the first instr is not a branch (call/jmp/ret/etc)
if (collectedInBoltedBinary()) {
if (FromBB->getInputOffset() != From) {
LLVM_DEBUG(dbgs() << "offset " << From << " does not match a BB in "
<< BF << '\n');
return false;
}
FromInstruction = nullptr;
} else {
LLVM_DEBUG(dbgs() << "no instruction for offset " << From << " in " << BF
<< '\n');
return false;
}
}
if (!FromBB->getSuccessor(ToBB->getLabel())) {
// Check if this is a recursive call or a return from a recursive call.
if (FromInstruction && ToBB->isEntryPoint() &&
(BC.MIB->isCall(*FromInstruction) ||
BC.MIB->isIndirectBranch(*FromInstruction))) {
// Execution count is already accounted for.
return true;
}
// For data collected in a bolted binary, we may have created two output BBs
// that map to one original block. Branches between these two blocks will
// appear here as one BB jumping to itself, even though it has no loop
// edges. Ignore these.
if (collectedInBoltedBinary() && FromBB == ToBB)
return true;
// Allow passthrough blocks.
BinaryBasicBlock *FTSuccessor = FromBB->getConditionalSuccessor(false);
if (FTSuccessor && FTSuccessor->succ_size() == 1 &&
FTSuccessor->getSuccessor(ToBB->getLabel())) {
BinaryBasicBlock::BinaryBranchInfo &FTBI =
FTSuccessor->getBranchInfo(*ToBB);
FTBI.Count += Count;
if (Count)
FTBI.MispredictedCount += Mispreds;
ToBB = FTSuccessor;
} else {
LLVM_DEBUG(dbgs() << "invalid branch in " << BF
<< formatv(": {0:x} -> {1:x}\n", From, To));
return false;
}
}
BinaryBasicBlock::BinaryBranchInfo &BI = FromBB->getBranchInfo(*ToBB);
BI.Count += Count;
// Only update mispredicted count if it the count was real.
if (Count) {
BI.MispredictedCount += Mispreds;
}
return true;
}
void DataReader::reportError(StringRef ErrorMsg) {
Diag << "Error reading BOLT data input file: line " << Line << ", column "
<< Col << ": " << ErrorMsg << '\n';
}
bool DataReader::expectAndConsumeFS() {
if (ParsingBuf[0] != FieldSeparator) {
reportError("expected field separator");
return false;
}
ParsingBuf = ParsingBuf.drop_front(1);
Col += 1;
return true;
}
void DataReader::consumeAllRemainingFS() {
while (ParsingBuf[0] == FieldSeparator) {
ParsingBuf = ParsingBuf.drop_front(1);
Col += 1;
}
}
bool DataReader::checkAndConsumeNewLine() {
if (ParsingBuf[0] != '\n')
return false;
ParsingBuf = ParsingBuf.drop_front(1);
Col = 0;
Line += 1;
return true;
}
ErrorOr<StringRef> DataReader::parseString(char EndChar, bool EndNl) {
if (EndChar == '\\') {
reportError("EndChar could not be backslash");
return make_error_code(llvm::errc::io_error);
}
std::string EndChars(1, EndChar);
EndChars.push_back('\\');
if (EndNl)
EndChars.push_back('\n');
size_t StringEnd = 0;
do {
StringEnd = ParsingBuf.find_first_of(EndChars, StringEnd);
if (StringEnd == StringRef::npos ||
(StringEnd == 0 && ParsingBuf[StringEnd] != '\\')) {
reportError("malformed field");
return make_error_code(llvm::errc::io_error);
}
if (ParsingBuf[StringEnd] != '\\')
break;
StringEnd += 2;
} while (true);
StringRef Str = ParsingBuf.substr(0, StringEnd);
// If EndNl was set and nl was found instead of EndChar, do not consume the
// new line.
bool EndNlInsteadOfEndChar = ParsingBuf[StringEnd] == '\n' && EndChar != '\n';
unsigned End = EndNlInsteadOfEndChar ? StringEnd : StringEnd + 1;
ParsingBuf = ParsingBuf.drop_front(End);
if (EndChar == '\n') {
Col = 0;
Line += 1;
} else {
Col += End;
}
return Str;
}
ErrorOr<int64_t> DataReader::parseNumberField(char EndChar, bool EndNl) {
ErrorOr<StringRef> NumStrRes = parseString(EndChar, EndNl);
if (std::error_code EC = NumStrRes.getError())
return EC;
StringRef NumStr = NumStrRes.get();
int64_t Num;
if (NumStr.getAsInteger(10, Num)) {
reportError("expected decimal number");
Diag << "Found: " << NumStr << "\n";
return make_error_code(llvm::errc::io_error);
}
return Num;
}
ErrorOr<uint64_t> DataReader::parseHexField(char EndChar, bool EndNl) {
ErrorOr<StringRef> NumStrRes = parseString(EndChar, EndNl);
if (std::error_code EC = NumStrRes.getError())
return EC;
StringRef NumStr = NumStrRes.get();
uint64_t Num;
if (NumStr.getAsInteger(16, Num)) {
reportError("expected hexidecimal number");
Diag << "Found: " << NumStr << "\n";
return make_error_code(llvm::errc::io_error);
}
return Num;
}
ErrorOr<Location> DataReader::parseLocation(char EndChar, bool EndNl,
bool ExpectMemLoc) {
// Read whether the location of the branch should be DSO or a symbol
// 0 means it is a DSO. 1 means it is a global symbol. 2 means it is a local
// symbol.
// The symbol flag is also used to tag memory load events by adding 3 to the
// base values, i.e. 3 not a symbol, 4 global symbol and 5 local symbol.
if (!ExpectMemLoc && ParsingBuf[0] != '0' && ParsingBuf[0] != '1' &&
ParsingBuf[0] != '2') {
reportError("expected 0, 1 or 2");
return make_error_code(llvm::errc::io_error);
}
if (ExpectMemLoc && ParsingBuf[0] != '3' && ParsingBuf[0] != '4' &&
ParsingBuf[0] != '5') {
reportError("expected 3, 4 or 5");
return make_error_code(llvm::errc::io_error);
}
bool IsSymbol =
(!ExpectMemLoc && (ParsingBuf[0] == '1' || ParsingBuf[0] == '2')) ||
(ExpectMemLoc && (ParsingBuf[0] == '4' || ParsingBuf[0] == '5'));
ParsingBuf = ParsingBuf.drop_front(1);
Col += 1;
if (!expectAndConsumeFS())
return make_error_code(llvm::errc::io_error);
consumeAllRemainingFS();
// Read the string containing the symbol or the DSO name
ErrorOr<StringRef> NameRes = parseString(FieldSeparator);
if (std::error_code EC = NameRes.getError())
return EC;
StringRef Name = NameRes.get();
consumeAllRemainingFS();
// Read the offset
ErrorOr<uint64_t> Offset = parseHexField(EndChar, EndNl);
if (std::error_code EC = Offset.getError())
return EC;
return Location(IsSymbol, Name, Offset.get());
}
ErrorOr<BranchInfo> DataReader::parseBranchInfo() {
ErrorOr<Location> Res = parseLocation(FieldSeparator);
if (std::error_code EC = Res.getError())
return EC;
Location From = Res.get();
consumeAllRemainingFS();
Res = parseLocation(FieldSeparator);
if (std::error_code EC = Res.getError())
return EC;
Location To = Res.get();
consumeAllRemainingFS();
ErrorOr<int64_t> MRes = parseNumberField(FieldSeparator);
if (std::error_code EC = MRes.getError())
return EC;
int64_t NumMispreds = MRes.get();
consumeAllRemainingFS();
ErrorOr<int64_t> BRes = parseNumberField(FieldSeparator, /* EndNl = */ true);
if (std::error_code EC = BRes.getError())
return EC;
int64_t NumBranches = BRes.get();
consumeAllRemainingFS();
if (!checkAndConsumeNewLine()) {
reportError("expected end of line");
return make_error_code(llvm::errc::io_error);
}
return BranchInfo(std::move(From), std::move(To), NumMispreds, NumBranches);
}
ErrorOr<MemInfo> DataReader::parseMemInfo() {
ErrorOr<Location> Res = parseMemLocation(FieldSeparator);
if (std::error_code EC = Res.getError())
return EC;
Location Offset = Res.get();
consumeAllRemainingFS();
Res = parseMemLocation(FieldSeparator);
if (std::error_code EC = Res.getError())
return EC;
Location Addr = Res.get();
consumeAllRemainingFS();
ErrorOr<int64_t> CountRes = parseNumberField(FieldSeparator, true);
if (std::error_code EC = CountRes.getError())
return EC;
consumeAllRemainingFS();