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llvm-project/llvm/lib/ProfileData/SampleProfReader.cpp

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//===- SampleProfReader.cpp - Read LLVM sample profile data ---------------===//
//
// 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 class that reads LLVM sample profiles. It
// supports three file formats: text, binary and gcov.
//
// The textual representation is useful for debugging and testing purposes. The
// binary representation is more compact, resulting in smaller file sizes.
//
// The gcov encoding is the one generated by GCC's AutoFDO profile creation
// tool (https://github.com/google/autofdo)
//
// All three encodings can be used interchangeably as an input sample profile.
//
//===----------------------------------------------------------------------===//
#include "llvm/ProfileData/SampleProfReader.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
using namespace llvm::sampleprof;
using namespace llvm;
/// \brief Print the samples collected for a function on stream \p OS.
///
/// \param OS Stream to emit the output to.
void FunctionSamples::print(raw_ostream &OS, unsigned Indent) const {
OS << TotalSamples << ", " << TotalHeadSamples << ", " << BodySamples.size()
<< " sampled lines\n";
for (const auto &SI : BodySamples) {
LineLocation Loc = SI.first;
const SampleRecord &Sample = SI.second;
OS.indent(Indent);
OS << "line offset: " << Loc.LineOffset
<< ", discriminator: " << Loc.Discriminator
<< ", number of samples: " << Sample.getSamples();
if (Sample.hasCalls()) {
OS << ", calls:";
for (const auto &I : Sample.getCallTargets())
OS << " " << I.first() << ":" << I.second;
}
OS << "\n";
}
for (const auto &CS : CallsiteSamples) {
CallsiteLocation Loc = CS.first;
const FunctionSamples &CalleeSamples = CS.second;
OS.indent(Indent);
OS << "line offset: " << Loc.LineOffset
<< ", discriminator: " << Loc.Discriminator
<< ", inlined callee: " << Loc.CalleeName << ": ";
CalleeSamples.print(OS, Indent + 2);
}
}
/// \brief Dump the function profile for \p FName.
///
/// \param FName Name of the function to print.
/// \param OS Stream to emit the output to.
void SampleProfileReader::dumpFunctionProfile(StringRef FName,
raw_ostream &OS) {
OS << "Function: " << FName << ": ";
Profiles[FName].print(OS);
}
/// \brief Dump all the function profiles found on stream \p OS.
void SampleProfileReader::dump(raw_ostream &OS) {
for (const auto &I : Profiles)
dumpFunctionProfile(I.getKey(), OS);
}
/// \brief Parse \p Input as function head.
///
/// Parse one line of \p Input, and update function name in \p FName,
/// function's total sample count in \p NumSamples, function's entry
/// count in \p NumHeadSamples.
///
/// \returns true if parsing is successful.
static bool ParseHead(const StringRef &Input, StringRef &FName,
uint64_t &NumSamples, uint64_t &NumHeadSamples) {
if (Input[0] == ' ')
return false;
size_t n2 = Input.rfind(':');
size_t n1 = Input.rfind(':', n2 - 1);
FName = Input.substr(0, n1);
if (Input.substr(n1 + 1, n2 - n1 - 1).getAsInteger(10, NumSamples))
return false;
if (Input.substr(n2 + 1).getAsInteger(10, NumHeadSamples))
return false;
return true;
}
/// \brief Returns true if line offset \p L is legal (only has 16 bits).
static bool isOffsetLegal(unsigned L) {
return (L & 0xffff) == L;
}
/// \brief Parse \p Input as line sample.
///
/// \param Input input line.
/// \param IsCallsite true if the line represents an inlined callsite.
/// \param Depth the depth of the inline stack.
/// \param NumSamples total samples of the line/inlined callsite.
/// \param LineOffset line offset to the start of the function.
/// \param Discriminator discriminator of the line.
/// \param TargetCountMap map from indirect call target to count.
///
/// returns true if parsing is successful.
static bool ParseLine(const StringRef &Input, bool &IsCallsite, uint32_t &Depth,
uint64_t &NumSamples, uint32_t &LineOffset,
uint32_t &Discriminator, StringRef &CalleeName,
DenseMap<StringRef, uint64_t> &TargetCountMap) {
for (Depth = 0; Input[Depth] == ' '; Depth++)
;
if (Depth == 0)
return false;
size_t n1 = Input.find(':');
StringRef Loc = Input.substr(Depth, n1 - Depth);
size_t n2 = Loc.find('.');
if (n2 == StringRef::npos) {
if (Loc.getAsInteger(10, LineOffset) || !isOffsetLegal(LineOffset))
return false;
Discriminator = 0;
} else {
if (Loc.substr(0, n2).getAsInteger(10, LineOffset))
return false;
if (Loc.substr(n2 + 1).getAsInteger(10, Discriminator))
return false;
}
StringRef Rest = Input.substr(n1 + 2);
if (Rest[0] >= '0' && Rest[0] <= '9') {
IsCallsite = false;
size_t n3 = Rest.find(' ');
if (n3 == StringRef::npos) {
if (Rest.getAsInteger(10, NumSamples))
return false;
} else {
if (Rest.substr(0, n3).getAsInteger(10, NumSamples))
return false;
}
while (n3 != StringRef::npos) {
n3 += Rest.substr(n3).find_first_not_of(' ');
Rest = Rest.substr(n3);
n3 = Rest.find(' ');
StringRef pair = Rest;
if (n3 != StringRef::npos) {
pair = Rest.substr(0, n3);
}
size_t n4 = pair.find(':');
uint64_t count;
if (pair.substr(n4 + 1).getAsInteger(10, count))
return false;
TargetCountMap[pair.substr(0, n4)] = count;
}
} else {
IsCallsite = true;
size_t n3 = Rest.find_last_of(':');
CalleeName = Rest.substr(0, n3);
if (Rest.substr(n3 + 1).getAsInteger(10, NumSamples))
return false;
}
return true;
}
/// \brief Load samples from a text file.
///
/// See the documentation at the top of the file for an explanation of
/// the expected format.
///
/// \returns true if the file was loaded successfully, false otherwise.
std::error_code SampleProfileReaderText::read() {
line_iterator LineIt(*Buffer, /*SkipBlanks=*/true, '#');
InlineCallStack InlineStack;
for (; !LineIt.is_at_eof(); ++LineIt) {
if ((*LineIt)[(*LineIt).find_first_not_of(' ')] == '#')
continue;
// Read the header of each function.
//
// Note that for function identifiers we are actually expecting
// mangled names, but we may not always get them. This happens when
// the compiler decides not to emit the function (e.g., it was inlined
// and removed). In this case, the binary will not have the linkage
// name for the function, so the profiler will emit the function's
// unmangled name, which may contain characters like ':' and '>' in its
// name (member functions, templates, etc).
//
// The only requirement we place on the identifier, then, is that it
// should not begin with a number.
if ((*LineIt)[0] != ' ') {
uint64_t NumSamples, NumHeadSamples;
StringRef FName;
if (!ParseHead(*LineIt, FName, NumSamples, NumHeadSamples)) {
reportError(LineIt.line_number(),
"Expected 'mangled_name:NUM:NUM', found " + *LineIt);
return sampleprof_error::malformed;
}
Profiles[FName] = FunctionSamples();
FunctionSamples &FProfile = Profiles[FName];
FProfile.addTotalSamples(NumSamples);
FProfile.addHeadSamples(NumHeadSamples);
InlineStack.clear();
InlineStack.push_back(&FProfile);
} else {
uint64_t NumSamples;
StringRef FName;
DenseMap<StringRef, uint64_t> TargetCountMap;
bool IsCallsite;
uint32_t Depth, LineOffset, Discriminator;
if (!ParseLine(*LineIt, IsCallsite, Depth, NumSamples, LineOffset,
Discriminator, FName, TargetCountMap)) {
reportError(LineIt.line_number(),
"Expected 'NUM[.NUM]: NUM[ mangled_name:NUM]*', found " +
*LineIt);
return sampleprof_error::malformed;
}
if (IsCallsite) {
while (InlineStack.size() > Depth) {
InlineStack.pop_back();
}
FunctionSamples &FSamples = InlineStack.back()->functionSamplesAt(
CallsiteLocation(LineOffset, Discriminator, FName));
FSamples.addTotalSamples(NumSamples);
InlineStack.push_back(&FSamples);
} else {
while (InlineStack.size() > Depth) {
InlineStack.pop_back();
}
FunctionSamples &FProfile = *InlineStack.back();
for (const auto &name_count : TargetCountMap) {
FProfile.addCalledTargetSamples(LineOffset, Discriminator,
name_count.first, name_count.second);
}
FProfile.addBodySamples(LineOffset, Discriminator, NumSamples);
}
}
}
return sampleprof_error::success;
}
template <typename T> ErrorOr<T> SampleProfileReaderBinary::readNumber() {
unsigned NumBytesRead = 0;
std::error_code EC;
uint64_t Val = decodeULEB128(Data, &NumBytesRead);
if (Val > std::numeric_limits<T>::max())
EC = sampleprof_error::malformed;
else if (Data + NumBytesRead > End)
EC = sampleprof_error::truncated;
else
EC = sampleprof_error::success;
if (EC) {
reportError(0, EC.message());
return EC;
}
Data += NumBytesRead;
return static_cast<T>(Val);
}
ErrorOr<StringRef> SampleProfileReaderBinary::readString() {
std::error_code EC;
StringRef Str(reinterpret_cast<const char *>(Data));
if (Data + Str.size() + 1 > End) {
EC = sampleprof_error::truncated;
reportError(0, EC.message());
return EC;
}
Data += Str.size() + 1;
return Str;
}
ErrorOr<StringRef> SampleProfileReaderBinary::readStringFromTable() {
std::error_code EC;
auto Idx = readNumber<uint32_t>();
if (std::error_code EC = Idx.getError())
return EC;
if (*Idx >= NameTable.size())
return sampleprof_error::truncated_name_table;
return NameTable[*Idx];
}
std::error_code
SampleProfileReaderBinary::readProfile(FunctionSamples &FProfile) {
auto NumSamples = readNumber<uint64_t>();
if (std::error_code EC = NumSamples.getError())
return EC;
FProfile.addTotalSamples(*NumSamples);
// Read the samples in the body.
auto NumRecords = readNumber<uint32_t>();
if (std::error_code EC = NumRecords.getError())
return EC;
for (uint32_t I = 0; I < *NumRecords; ++I) {
auto LineOffset = readNumber<uint64_t>();
if (std::error_code EC = LineOffset.getError())
return EC;
if (!isOffsetLegal(*LineOffset)) {
return std::error_code();
}
auto Discriminator = readNumber<uint64_t>();
if (std::error_code EC = Discriminator.getError())
return EC;
auto NumSamples = readNumber<uint64_t>();
if (std::error_code EC = NumSamples.getError())
return EC;
auto NumCalls = readNumber<uint32_t>();
if (std::error_code EC = NumCalls.getError())
return EC;
for (uint32_t J = 0; J < *NumCalls; ++J) {
auto CalledFunction(readStringFromTable());
if (std::error_code EC = CalledFunction.getError())
return EC;
auto CalledFunctionSamples = readNumber<uint64_t>();
if (std::error_code EC = CalledFunctionSamples.getError())
return EC;
FProfile.addCalledTargetSamples(*LineOffset, *Discriminator,
*CalledFunction, *CalledFunctionSamples);
}
FProfile.addBodySamples(*LineOffset, *Discriminator, *NumSamples);
}
// Read all the samples for inlined function calls.
auto NumCallsites = readNumber<uint32_t>();
if (std::error_code EC = NumCallsites.getError())
return EC;
for (uint32_t J = 0; J < *NumCallsites; ++J) {
auto LineOffset = readNumber<uint64_t>();
if (std::error_code EC = LineOffset.getError())
return EC;
auto Discriminator = readNumber<uint64_t>();
if (std::error_code EC = Discriminator.getError())
return EC;
auto FName(readStringFromTable());
if (std::error_code EC = FName.getError())
return EC;
FunctionSamples &CalleeProfile = FProfile.functionSamplesAt(
CallsiteLocation(*LineOffset, *Discriminator, *FName));
if (std::error_code EC = readProfile(CalleeProfile))
return EC;
}
return sampleprof_error::success;
}
std::error_code SampleProfileReaderBinary::read() {
while (!at_eof()) {
auto NumHeadSamples = readNumber<uint64_t>();
if (std::error_code EC = NumHeadSamples.getError())
return EC;
auto FName(readStringFromTable());
if (std::error_code EC = FName.getError())
return EC;
Profiles[*FName] = FunctionSamples();
FunctionSamples &FProfile = Profiles[*FName];
FProfile.addHeadSamples(*NumHeadSamples);
if (std::error_code EC = readProfile(FProfile))
return EC;
}
return sampleprof_error::success;
}
std::error_code SampleProfileReaderBinary::readHeader() {
Data = reinterpret_cast<const uint8_t *>(Buffer->getBufferStart());
End = Data + Buffer->getBufferSize();
// Read and check the magic identifier.
auto Magic = readNumber<uint64_t>();
if (std::error_code EC = Magic.getError())
return EC;
else if (*Magic != SPMagic())
return sampleprof_error::bad_magic;
// Read the version number.
auto Version = readNumber<uint64_t>();
if (std::error_code EC = Version.getError())
return EC;
else if (*Version != SPVersion())
return sampleprof_error::unsupported_version;
// Read the name table.
auto Size = readNumber<uint32_t>();
if (std::error_code EC = Size.getError())
return EC;
NameTable.reserve(*Size);
for (uint32_t I = 0; I < *Size; ++I) {
auto Name(readString());
if (std::error_code EC = Name.getError())
return EC;
NameTable.push_back(*Name);
}
return sampleprof_error::success;
}
bool SampleProfileReaderBinary::hasFormat(const MemoryBuffer &Buffer) {
const uint8_t *Data =
reinterpret_cast<const uint8_t *>(Buffer.getBufferStart());
uint64_t Magic = decodeULEB128(Data);
return Magic == SPMagic();
}
std::error_code SampleProfileReaderGCC::skipNextWord() {
uint32_t dummy;
if (!GcovBuffer.readInt(dummy))
return sampleprof_error::truncated;
return sampleprof_error::success;
}
template <typename T> ErrorOr<T> SampleProfileReaderGCC::readNumber() {
if (sizeof(T) <= sizeof(uint32_t)) {
uint32_t Val;
if (GcovBuffer.readInt(Val) && Val <= std::numeric_limits<T>::max())
return static_cast<T>(Val);
} else if (sizeof(T) <= sizeof(uint64_t)) {
uint64_t Val;
if (GcovBuffer.readInt64(Val) && Val <= std::numeric_limits<T>::max())
return static_cast<T>(Val);
}
std::error_code EC = sampleprof_error::malformed;
reportError(0, EC.message());
return EC;
}
ErrorOr<StringRef> SampleProfileReaderGCC::readString() {
StringRef Str;
if (!GcovBuffer.readString(Str))
return sampleprof_error::truncated;
return Str;
}
std::error_code SampleProfileReaderGCC::readHeader() {
// Read the magic identifier.
if (!GcovBuffer.readGCDAFormat())
return sampleprof_error::unrecognized_format;
// Read the version number. Note - the GCC reader does not validate this
// version, but the profile creator generates v704.
GCOV::GCOVVersion version;
if (!GcovBuffer.readGCOVVersion(version))
return sampleprof_error::unrecognized_format;
if (version != GCOV::V704)
return sampleprof_error::unsupported_version;
// Skip the empty integer.
if (std::error_code EC = skipNextWord())
return EC;
return sampleprof_error::success;
}
std::error_code SampleProfileReaderGCC::readSectionTag(uint32_t Expected) {
uint32_t Tag;
if (!GcovBuffer.readInt(Tag))
return sampleprof_error::truncated;
if (Tag != Expected)
return sampleprof_error::malformed;
if (std::error_code EC = skipNextWord())
return EC;
return sampleprof_error::success;
}
std::error_code SampleProfileReaderGCC::readNameTable() {
if (std::error_code EC = readSectionTag(GCOVTagAFDOFileNames))
return EC;
uint32_t Size;
if (!GcovBuffer.readInt(Size))
return sampleprof_error::truncated;
for (uint32_t I = 0; I < Size; ++I) {
StringRef Str;
if (!GcovBuffer.readString(Str))
return sampleprof_error::truncated;
Names.push_back(Str);
}
return sampleprof_error::success;
}
std::error_code SampleProfileReaderGCC::readFunctionProfiles() {
if (std::error_code EC = readSectionTag(GCOVTagAFDOFunction))
return EC;
uint32_t NumFunctions;
if (!GcovBuffer.readInt(NumFunctions))
return sampleprof_error::truncated;
InlineCallStack Stack;
for (uint32_t I = 0; I < NumFunctions; ++I)
if (std::error_code EC = readOneFunctionProfile(Stack, true, 0))
return EC;
return sampleprof_error::success;
}
std::error_code SampleProfileReaderGCC::readOneFunctionProfile(
const InlineCallStack &InlineStack, bool Update, uint32_t Offset) {
uint64_t HeadCount = 0;
if (InlineStack.size() == 0)
if (!GcovBuffer.readInt64(HeadCount))
return sampleprof_error::truncated;
uint32_t NameIdx;
if (!GcovBuffer.readInt(NameIdx))
return sampleprof_error::truncated;
StringRef Name(Names[NameIdx]);
uint32_t NumPosCounts;
if (!GcovBuffer.readInt(NumPosCounts))
return sampleprof_error::truncated;
uint32_t NumCallsites;
if (!GcovBuffer.readInt(NumCallsites))
return sampleprof_error::truncated;
FunctionSamples *FProfile = nullptr;
if (InlineStack.size() == 0) {
// If this is a top function that we have already processed, do not
// update its profile again. This happens in the presence of
// function aliases. Since these aliases share the same function
// body, there will be identical replicated profiles for the
// original function. In this case, we simply not bother updating
// the profile of the original function.
FProfile = &Profiles[Name];
FProfile->addHeadSamples(HeadCount);
if (FProfile->getTotalSamples() > 0)
Update = false;
} else {
// Otherwise, we are reading an inlined instance. The top of the
// inline stack contains the profile of the caller. Insert this
// callee in the caller's CallsiteMap.
FunctionSamples *CallerProfile = InlineStack.front();
uint32_t LineOffset = Offset >> 16;
uint32_t Discriminator = Offset & 0xffff;
FProfile = &CallerProfile->functionSamplesAt(
CallsiteLocation(LineOffset, Discriminator, Name));
}
for (uint32_t I = 0; I < NumPosCounts; ++I) {
uint32_t Offset;
if (!GcovBuffer.readInt(Offset))
return sampleprof_error::truncated;
uint32_t NumTargets;
if (!GcovBuffer.readInt(NumTargets))
return sampleprof_error::truncated;
uint64_t Count;
if (!GcovBuffer.readInt64(Count))
return sampleprof_error::truncated;
// The line location is encoded in the offset as:
// high 16 bits: line offset to the start of the function.
// low 16 bits: discriminator.
uint32_t LineOffset = Offset >> 16;
uint32_t Discriminator = Offset & 0xffff;
InlineCallStack NewStack;
NewStack.push_back(FProfile);
NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
if (Update) {
// Walk up the inline stack, adding the samples on this line to
// the total sample count of the callers in the chain.
for (auto CallerProfile : NewStack)
CallerProfile->addTotalSamples(Count);
// Update the body samples for the current profile.
FProfile->addBodySamples(LineOffset, Discriminator, Count);
}
// Process the list of functions called at an indirect call site.
// These are all the targets that a function pointer (or virtual
// function) resolved at runtime.
for (uint32_t J = 0; J < NumTargets; J++) {
uint32_t HistVal;
if (!GcovBuffer.readInt(HistVal))
return sampleprof_error::truncated;
if (HistVal != HIST_TYPE_INDIR_CALL_TOPN)
return sampleprof_error::malformed;
uint64_t TargetIdx;
if (!GcovBuffer.readInt64(TargetIdx))
return sampleprof_error::truncated;
StringRef TargetName(Names[TargetIdx]);
uint64_t TargetCount;
if (!GcovBuffer.readInt64(TargetCount))
return sampleprof_error::truncated;
if (Update) {
FunctionSamples &TargetProfile = Profiles[TargetName];
TargetProfile.addCalledTargetSamples(LineOffset, Discriminator,
TargetName, TargetCount);
}
}
}
// Process all the inlined callers into the current function. These
// are all the callsites that were inlined into this function.
for (uint32_t I = 0; I < NumCallsites; I++) {
// The offset is encoded as:
// high 16 bits: line offset to the start of the function.
// low 16 bits: discriminator.
uint32_t Offset;
if (!GcovBuffer.readInt(Offset))
return sampleprof_error::truncated;
InlineCallStack NewStack;
NewStack.push_back(FProfile);
NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
if (std::error_code EC = readOneFunctionProfile(NewStack, Update, Offset))
return EC;
}
return sampleprof_error::success;
}
/// \brief Read a GCC AutoFDO profile.
///
/// This format is generated by the Linux Perf conversion tool at
/// https://github.com/google/autofdo.
std::error_code SampleProfileReaderGCC::read() {
// Read the string table.
if (std::error_code EC = readNameTable())
return EC;
// Read the source profile.
if (std::error_code EC = readFunctionProfiles())
return EC;
return sampleprof_error::success;
}
bool SampleProfileReaderGCC::hasFormat(const MemoryBuffer &Buffer) {
StringRef Magic(reinterpret_cast<const char *>(Buffer.getBufferStart()));
return Magic == "adcg*704";
}
/// \brief Prepare a memory buffer for the contents of \p Filename.
///
/// \returns an error code indicating the status of the buffer.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
setupMemoryBuffer(std::string Filename) {
auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(Filename);
if (std::error_code EC = BufferOrErr.getError())
return EC;
auto Buffer = std::move(BufferOrErr.get());
// Sanity check the file.
if (Buffer->getBufferSize() > std::numeric_limits<uint32_t>::max())
return sampleprof_error::too_large;
return std::move(Buffer);
}
/// \brief Create a sample profile reader based on the format of the input file.
///
/// \param Filename The file to open.
///
/// \param Reader The reader to instantiate according to \p Filename's format.
///
/// \param C The LLVM context to use to emit diagnostics.
///
/// \returns an error code indicating the status of the created reader.
ErrorOr<std::unique_ptr<SampleProfileReader>>
SampleProfileReader::create(StringRef Filename, LLVMContext &C) {
auto BufferOrError = setupMemoryBuffer(Filename);
if (std::error_code EC = BufferOrError.getError())
return EC;
auto Buffer = std::move(BufferOrError.get());
std::unique_ptr<SampleProfileReader> Reader;
if (SampleProfileReaderBinary::hasFormat(*Buffer))
Reader.reset(new SampleProfileReaderBinary(std::move(Buffer), C));
else if (SampleProfileReaderGCC::hasFormat(*Buffer))
Reader.reset(new SampleProfileReaderGCC(std::move(Buffer), C));
else
Reader.reset(new SampleProfileReaderText(std::move(Buffer), C));
if (std::error_code EC = Reader->readHeader())
return EC;
return std::move(Reader);
}
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