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

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//=-- CoverageMappingReader.cpp - Code coverage mapping reader ----*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for reading coverage mapping data for
// instrumentation based coverage.
//
//===----------------------------------------------------------------------===//
#include "llvm/ProfileData/CoverageMappingReader.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Object/MachOUniversal.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace coverage;
using namespace object;
#define DEBUG_TYPE "coverage-mapping"
void CoverageMappingIterator::increment() {
// Check if all the records were read or if an error occurred while reading
// the next record.
if (Reader->readNextRecord(Record))
*this = CoverageMappingIterator();
}
std::error_code RawCoverageReader::readULEB128(uint64_t &Result) {
if (Data.size() < 1)
return coveragemap_error::truncated;
unsigned N = 0;
Result = decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
if (N > Data.size())
return coveragemap_error::malformed;
Data = Data.substr(N);
return std::error_code();
}
std::error_code RawCoverageReader::readIntMax(uint64_t &Result,
uint64_t MaxPlus1) {
if (auto Err = readULEB128(Result))
return Err;
if (Result >= MaxPlus1)
return coveragemap_error::malformed;
return std::error_code();
}
std::error_code RawCoverageReader::readSize(uint64_t &Result) {
if (auto Err = readULEB128(Result))
return Err;
// Sanity check the number.
if (Result > Data.size())
return coveragemap_error::malformed;
return std::error_code();
}
std::error_code RawCoverageReader::readString(StringRef &Result) {
uint64_t Length;
if (auto Err = readSize(Length))
return Err;
Result = Data.substr(0, Length);
Data = Data.substr(Length);
return std::error_code();
}
std::error_code RawCoverageFilenamesReader::read() {
uint64_t NumFilenames;
if (auto Err = readSize(NumFilenames))
return Err;
for (size_t I = 0; I < NumFilenames; ++I) {
StringRef Filename;
if (auto Err = readString(Filename))
return Err;
Filenames.push_back(Filename);
}
return std::error_code();
}
std::error_code RawCoverageMappingReader::decodeCounter(unsigned Value,
Counter &C) {
auto Tag = Value & Counter::EncodingTagMask;
switch (Tag) {
case Counter::Zero:
C = Counter::getZero();
return std::error_code();
case Counter::CounterValueReference:
C = Counter::getCounter(Value >> Counter::EncodingTagBits);
return std::error_code();
default:
break;
}
Tag -= Counter::Expression;
switch (Tag) {
case CounterExpression::Subtract:
case CounterExpression::Add: {
auto ID = Value >> Counter::EncodingTagBits;
if (ID >= Expressions.size())
return coveragemap_error::malformed;
Expressions[ID].Kind = CounterExpression::ExprKind(Tag);
C = Counter::getExpression(ID);
break;
}
default:
return coveragemap_error::malformed;
}
return std::error_code();
}
std::error_code RawCoverageMappingReader::readCounter(Counter &C) {
uint64_t EncodedCounter;
if (auto Err =
readIntMax(EncodedCounter, std::numeric_limits<unsigned>::max()))
return Err;
if (auto Err = decodeCounter(EncodedCounter, C))
return Err;
return std::error_code();
}
static const unsigned EncodingExpansionRegionBit = 1
<< Counter::EncodingTagBits;
/// \brief Read the sub-array of regions for the given inferred file id.
/// \param NumFileIDs the number of file ids that are defined for this
/// function.
std::error_code RawCoverageMappingReader::readMappingRegionsSubArray(
std::vector<CounterMappingRegion> &MappingRegions, unsigned InferredFileID,
size_t NumFileIDs) {
uint64_t NumRegions;
if (auto Err = readSize(NumRegions))
return Err;
unsigned LineStart = 0;
for (size_t I = 0; I < NumRegions; ++I) {
Counter C;
CounterMappingRegion::RegionKind Kind = CounterMappingRegion::CodeRegion;
// Read the combined counter + region kind.
uint64_t EncodedCounterAndRegion;
if (auto Err = readIntMax(EncodedCounterAndRegion,
std::numeric_limits<unsigned>::max()))
return Err;
unsigned Tag = EncodedCounterAndRegion & Counter::EncodingTagMask;
uint64_t ExpandedFileID = 0;
if (Tag != Counter::Zero) {
if (auto Err = decodeCounter(EncodedCounterAndRegion, C))
return Err;
} else {
// Is it an expansion region?
if (EncodedCounterAndRegion & EncodingExpansionRegionBit) {
Kind = CounterMappingRegion::ExpansionRegion;
ExpandedFileID = EncodedCounterAndRegion >>
Counter::EncodingCounterTagAndExpansionRegionTagBits;
if (ExpandedFileID >= NumFileIDs)
return coveragemap_error::malformed;
} else {
switch (EncodedCounterAndRegion >>
Counter::EncodingCounterTagAndExpansionRegionTagBits) {
case CounterMappingRegion::CodeRegion:
// Don't do anything when we have a code region with a zero counter.
break;
case CounterMappingRegion::SkippedRegion:
Kind = CounterMappingRegion::SkippedRegion;
break;
default:
return coveragemap_error::malformed;
}
}
}
// Read the source range.
uint64_t LineStartDelta, ColumnStart, NumLines, ColumnEnd;
if (auto Err =
readIntMax(LineStartDelta, std::numeric_limits<unsigned>::max()))
return Err;
if (auto Err = readULEB128(ColumnStart))
return Err;
if (ColumnStart > std::numeric_limits<unsigned>::max())
return coveragemap_error::malformed;
if (auto Err = readIntMax(NumLines, std::numeric_limits<unsigned>::max()))
return Err;
if (auto Err = readIntMax(ColumnEnd, std::numeric_limits<unsigned>::max()))
return Err;
LineStart += LineStartDelta;
// Adjust the column locations for the empty regions that are supposed to
// cover whole lines. Those regions should be encoded with the
// column range (1 -> std::numeric_limits<unsigned>::max()), but because
// the encoded std::numeric_limits<unsigned>::max() is several bytes long,
// we set the column range to (0 -> 0) to ensure that the column start and
// column end take up one byte each.
// The std::numeric_limits<unsigned>::max() is used to represent a column
// position at the end of the line without knowing the length of that line.
if (ColumnStart == 0 && ColumnEnd == 0) {
ColumnStart = 1;
ColumnEnd = std::numeric_limits<unsigned>::max();
}
DEBUG({
dbgs() << "Counter in file " << InferredFileID << " " << LineStart << ":"
<< ColumnStart << " -> " << (LineStart + NumLines) << ":"
<< ColumnEnd << ", ";
if (Kind == CounterMappingRegion::ExpansionRegion)
dbgs() << "Expands to file " << ExpandedFileID;
else
CounterMappingContext(Expressions).dump(C, dbgs());
dbgs() << "\n";
});
MappingRegions.push_back(CounterMappingRegion(
C, InferredFileID, ExpandedFileID, LineStart, ColumnStart,
LineStart + NumLines, ColumnEnd, Kind));
}
return std::error_code();
}
std::error_code RawCoverageMappingReader::read() {
// Read the virtual file mapping.
llvm::SmallVector<unsigned, 8> VirtualFileMapping;
uint64_t NumFileMappings;
if (auto Err = readSize(NumFileMappings))
return Err;
for (size_t I = 0; I < NumFileMappings; ++I) {
uint64_t FilenameIndex;
if (auto Err = readIntMax(FilenameIndex, TranslationUnitFilenames.size()))
return Err;
VirtualFileMapping.push_back(FilenameIndex);
}
// Construct the files using unique filenames and virtual file mapping.
for (auto I : VirtualFileMapping) {
Filenames.push_back(TranslationUnitFilenames[I]);
}
// Read the expressions.
uint64_t NumExpressions;
if (auto Err = readSize(NumExpressions))
return Err;
// Create an array of dummy expressions that get the proper counters
// when the expressions are read, and the proper kinds when the counters
// are decoded.
Expressions.resize(
NumExpressions,
CounterExpression(CounterExpression::Subtract, Counter(), Counter()));
for (size_t I = 0; I < NumExpressions; ++I) {
if (auto Err = readCounter(Expressions[I].LHS))
return Err;
if (auto Err = readCounter(Expressions[I].RHS))
return Err;
}
// Read the mapping regions sub-arrays.
for (unsigned InferredFileID = 0, S = VirtualFileMapping.size();
InferredFileID < S; ++InferredFileID) {
if (auto Err = readMappingRegionsSubArray(MappingRegions, InferredFileID,
VirtualFileMapping.size()))
return Err;
}
// Set the counters for the expansion regions.
// i.e. Counter of expansion region = counter of the first region
// from the expanded file.
// Perform multiple passes to correctly propagate the counters through
// all the nested expansion regions.
SmallVector<CounterMappingRegion *, 8> FileIDExpansionRegionMapping;
FileIDExpansionRegionMapping.resize(VirtualFileMapping.size(), nullptr);
for (unsigned Pass = 1, S = VirtualFileMapping.size(); Pass < S; ++Pass) {
for (auto &R : MappingRegions) {
if (R.Kind != CounterMappingRegion::ExpansionRegion)
continue;
assert(!FileIDExpansionRegionMapping[R.ExpandedFileID]);
FileIDExpansionRegionMapping[R.ExpandedFileID] = &R;
}
for (auto &R : MappingRegions) {
if (FileIDExpansionRegionMapping[R.FileID]) {
FileIDExpansionRegionMapping[R.FileID]->Count = R.Count;
FileIDExpansionRegionMapping[R.FileID] = nullptr;
}
}
}
return std::error_code();
}
namespace {
/// \brief A helper structure to access the data from a section
/// in an object file.
struct SectionData {
StringRef Data;
uint64_t Address;
std::error_code load(SectionRef &Section) {
if (auto Err = Section.getContents(Data))
return Err;
Address = Section.getAddress();
return std::error_code();
}
std::error_code get(uint64_t Pointer, size_t Size, StringRef &Result) {
if (Pointer < Address)
return coveragemap_error::malformed;
auto Offset = Pointer - Address;
if (Offset + Size > Data.size())
return coveragemap_error::malformed;
Result = Data.substr(Pointer - Address, Size);
return std::error_code();
}
};
}
template <typename T, support::endianness Endian>
std::error_code readCoverageMappingData(
SectionData &ProfileNames, StringRef Data,
std::vector<BinaryCoverageReader::ProfileMappingRecord> &Records,
std::vector<StringRef> &Filenames) {
using namespace support;
llvm::DenseSet<T> UniqueFunctionMappingData;
// Read the records in the coverage data section.
for (const char *Buf = Data.data(), *End = Buf + Data.size(); Buf < End;) {
if (Buf + 4 * sizeof(uint32_t) > End)
return coveragemap_error::malformed;
uint32_t NRecords = endian::readNext<uint32_t, Endian, unaligned>(Buf);
uint32_t FilenamesSize = endian::readNext<uint32_t, Endian, unaligned>(Buf);
uint32_t CoverageSize = endian::readNext<uint32_t, Endian, unaligned>(Buf);
uint32_t Version = endian::readNext<uint32_t, Endian, unaligned>(Buf);
switch (Version) {
case CoverageMappingVersion1:
break;
default:
return coveragemap_error::unsupported_version;
}
// Skip past the function records, saving the start and end for later.
const char *FunBuf = Buf;
Buf += NRecords * sizeof(coverage::CovMapFunctionRecord<T>);
const char *FunEnd = Buf;
// Get the filenames.
if (Buf + FilenamesSize > End)
return coveragemap_error::malformed;
size_t FilenamesBegin = Filenames.size();
RawCoverageFilenamesReader Reader(StringRef(Buf, FilenamesSize), Filenames);
if (auto Err = Reader.read())
return Err;
Buf += FilenamesSize;
// We'll read the coverage mapping records in the loop below.
const char *CovBuf = Buf;
Buf += CoverageSize;
const char *CovEnd = Buf;
if (Buf > End)
return coveragemap_error::malformed;
// Each coverage map has an alignment of 8, so we need to adjust alignment
// before reading the next map.
Buf += alignmentAdjustment(Buf, 8);
auto CFR =
reinterpret_cast<const coverage::CovMapFunctionRecord<T> *>(FunBuf);
while ((const char *)CFR < FunEnd) {
// Read the function information
T NamePtr = endian::byte_swap<T, Endian>(CFR->NamePtr);
uint32_t NameSize = endian::byte_swap<uint32_t, Endian>(CFR->NameSize);
uint32_t DataSize = endian::byte_swap<uint32_t, Endian>(CFR->DataSize);
uint64_t FuncHash = endian::byte_swap<uint64_t, Endian>(CFR->FuncHash);
CFR++;
// Now use that to read the coverage data.
if (CovBuf + DataSize > CovEnd)
return coveragemap_error::malformed;
auto Mapping = StringRef(CovBuf, DataSize);
CovBuf += DataSize;
// Ignore this record if we already have a record that points to the same
// function name. This is useful to ignore the redundant records for the
// functions with ODR linkage.
if (!UniqueFunctionMappingData.insert(NamePtr).second)
continue;
// Finally, grab the name and create a record.
StringRef FuncName;
if (std::error_code EC = ProfileNames.get(NamePtr, NameSize, FuncName))
return EC;
Records.push_back(BinaryCoverageReader::ProfileMappingRecord(
CoverageMappingVersion(Version), FuncName, FuncHash, Mapping,
FilenamesBegin, Filenames.size() - FilenamesBegin));
}
}
return std::error_code();
}
static const char *TestingFormatMagic = "llvmcovmtestdata";
static std::error_code loadTestingFormat(StringRef Data,
SectionData &ProfileNames,
StringRef &CoverageMapping,
uint8_t &BytesInAddress,
support::endianness &Endian) {
BytesInAddress = 8;
Endian = support::endianness::little;
Data = Data.substr(StringRef(TestingFormatMagic).size());
if (Data.size() < 1)
return coveragemap_error::truncated;
unsigned N = 0;
auto ProfileNamesSize =
decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
if (N > Data.size())
return coveragemap_error::malformed;
Data = Data.substr(N);
if (Data.size() < 1)
return coveragemap_error::truncated;
N = 0;
ProfileNames.Address =
decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
if (N > Data.size())
return coveragemap_error::malformed;
Data = Data.substr(N);
if (Data.size() < ProfileNamesSize)
return coveragemap_error::malformed;
ProfileNames.Data = Data.substr(0, ProfileNamesSize);
CoverageMapping = Data.substr(ProfileNamesSize);
return std::error_code();
}
static ErrorOr<SectionRef> lookupSection(ObjectFile &OF, StringRef Name) {
StringRef FoundName;
for (const auto &Section : OF.sections()) {
if (auto EC = Section.getName(FoundName))
return EC;
if (FoundName == Name)
return Section;
}
return coveragemap_error::no_data_found;
}
static std::error_code loadBinaryFormat(MemoryBufferRef ObjectBuffer,
SectionData &ProfileNames,
StringRef &CoverageMapping,
uint8_t &BytesInAddress,
support::endianness &Endian,
StringRef Arch) {
auto BinOrErr = object::createBinary(ObjectBuffer);
if (std::error_code EC = BinOrErr.getError())
return EC;
auto Bin = std::move(BinOrErr.get());
std::unique_ptr<ObjectFile> OF;
if (auto *Universal = dyn_cast<object::MachOUniversalBinary>(Bin.get())) {
// If we have a universal binary, try to look up the object for the
// appropriate architecture.
auto ObjectFileOrErr = Universal->getObjectForArch(Arch);
if (std::error_code EC = ObjectFileOrErr.getError())
return EC;
OF = std::move(ObjectFileOrErr.get());
} else if (isa<object::ObjectFile>(Bin.get())) {
// For any other object file, upcast and take ownership.
OF.reset(cast<object::ObjectFile>(Bin.release()));
// If we've asked for a particular arch, make sure they match.
if (!Arch.empty() && OF->getArch() != Triple(Arch).getArch())
return object_error::arch_not_found;
} else
// We can only handle object files.
return coveragemap_error::malformed;
// The coverage uses native pointer sizes for the object it's written in.
BytesInAddress = OF->getBytesInAddress();
Endian = OF->isLittleEndian() ? support::endianness::little
: support::endianness::big;
// Look for the sections that we are interested in.
auto NamesSection = lookupSection(*OF, getInstrProfNameSectionName(false));
if (auto EC = NamesSection.getError())
return EC;
auto CoverageSection =
lookupSection(*OF, getInstrProfCoverageSectionName(false));
if (auto EC = CoverageSection.getError())
return EC;
// Get the contents of the given sections.
if (std::error_code EC = CoverageSection->getContents(CoverageMapping))
return EC;
if (std::error_code EC = ProfileNames.load(*NamesSection))
return EC;
return std::error_code();
}
ErrorOr<std::unique_ptr<BinaryCoverageReader>>
BinaryCoverageReader::create(std::unique_ptr<MemoryBuffer> &ObjectBuffer,
StringRef Arch) {
std::unique_ptr<BinaryCoverageReader> Reader(new BinaryCoverageReader());
SectionData Profile;
StringRef Coverage;
uint8_t BytesInAddress;
support::endianness Endian;
std::error_code EC;
if (ObjectBuffer->getBuffer().startswith(TestingFormatMagic))
// This is a special format used for testing.
EC = loadTestingFormat(ObjectBuffer->getBuffer(), Profile, Coverage,
BytesInAddress, Endian);
else
EC = loadBinaryFormat(ObjectBuffer->getMemBufferRef(), Profile, Coverage,
BytesInAddress, Endian, Arch);
if (EC)
return EC;
if (BytesInAddress == 4 && Endian == support::endianness::little)
EC = readCoverageMappingData<uint32_t, support::endianness::little>(
Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
else if (BytesInAddress == 4 && Endian == support::endianness::big)
EC = readCoverageMappingData<uint32_t, support::endianness::big>(
Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
else if (BytesInAddress == 8 && Endian == support::endianness::little)
EC = readCoverageMappingData<uint64_t, support::endianness::little>(
Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
else if (BytesInAddress == 8 && Endian == support::endianness::big)
EC = readCoverageMappingData<uint64_t, support::endianness::big>(
Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
else
return coveragemap_error::malformed;
if (EC)
return EC;
return std::move(Reader);
}
std::error_code
BinaryCoverageReader::readNextRecord(CoverageMappingRecord &Record) {
if (CurrentRecord >= MappingRecords.size())
return coveragemap_error::eof;
FunctionsFilenames.clear();
Expressions.clear();
MappingRegions.clear();
auto &R = MappingRecords[CurrentRecord];
RawCoverageMappingReader Reader(
R.CoverageMapping,
makeArrayRef(Filenames).slice(R.FilenamesBegin, R.FilenamesSize),
FunctionsFilenames, Expressions, MappingRegions);
if (auto Err = Reader.read())
return Err;
Record.FunctionName = R.FunctionName;
Record.FunctionHash = R.FunctionHash;
Record.Filenames = FunctionsFilenames;
Record.Expressions = Expressions;
Record.MappingRegions = MappingRegions;
++CurrentRecord;
return std::error_code();
}
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