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[memprof] Introduce IndexedMemProfReader (NFC) #89331

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Merged
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Apr 19, 2024
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[memprof] Introduce IndexedMemProfReader (NFC) #89331

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33 changes: 24 additions & 9 deletions llvm/include/llvm/ProfileData/InstrProfReader.h
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Original file line number Diff line number Diff line change
Expand Up @@ -647,6 +647,26 @@ class InstrProfReaderRemapper {
ArrayRef<NamedInstrProfRecord> &Data) = 0;
};

class IndexedMemProfReader {
private:
/// MemProf profile schema (if available).
memprof::MemProfSchema Schema;
/// MemProf record profile data on-disk indexed via llvm::md5(FunctionName).
std::unique_ptr<MemProfRecordHashTable> MemProfRecordTable;
/// MemProf frame profile data on-disk indexed via frame id.
std::unique_ptr<MemProfFrameHashTable> MemProfFrameTable;
/// MemProf call stack data on-disk indexed via call stack id.
std::unique_ptr<MemProfCallStackHashTable> MemProfCallStackTable;

public:
IndexedMemProfReader() = default;

Error deserialize(const unsigned char *Start, uint64_t MemProfOffset);

Expected<memprof::MemProfRecord>
getMemProfRecord(const uint64_t FuncNameHash) const;
};

/// Reader for the indexed binary instrprof format.
class IndexedInstrProfReader : public InstrProfReader {
private:
Expand All @@ -662,14 +682,7 @@ class IndexedInstrProfReader : public InstrProfReader {
std::unique_ptr<ProfileSummary> Summary;
/// Context sensitive profile summary data.
std::unique_ptr<ProfileSummary> CS_Summary;
/// MemProf profile schema (if available).
memprof::MemProfSchema Schema;
/// MemProf record profile data on-disk indexed via llvm::md5(FunctionName).
std::unique_ptr<MemProfRecordHashTable> MemProfRecordTable;
/// MemProf frame profile data on-disk indexed via frame id.
std::unique_ptr<MemProfFrameHashTable> MemProfFrameTable;
/// MemProf call stack data on-disk indexed via call stack id.
std::unique_ptr<MemProfCallStackHashTable> MemProfCallStackTable;
IndexedMemProfReader MemProfReader;
/// VTableNamePtr points to the beginning of compressed vtable names.
/// When a symtab is constructed from profiles by llvm-profdata, the list of
/// names could be decompressed based on `VTableNamePtr` and
Expand Down Expand Up @@ -753,7 +766,9 @@ class IndexedInstrProfReader : public InstrProfReader {

/// Return the memprof record for the function identified by
/// llvm::md5(Name).
Expected<memprof::MemProfRecord> getMemProfRecord(uint64_t FuncNameHash);
Expected<memprof::MemProfRecord> getMemProfRecord(uint64_t FuncNameHash) {
return MemProfReader.getMemProfRecord(FuncNameHash);
}

/// Fill Counts with the profile data for the given function name.
Error getFunctionCounts(StringRef FuncName, uint64_t FuncHash,
Expand Down
186 changes: 96 additions & 90 deletions llvm/lib/ProfileData/InstrProfReader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1202,6 +1202,99 @@ IndexedInstrProfReader::readSummary(IndexedInstrProf::ProfVersion Version,
}
}

Error IndexedMemProfReader::deserialize(const unsigned char *Start,
uint64_t MemProfOffset) {
const unsigned char *Ptr = Start + MemProfOffset;

// Read the first 64-bit word, which may be RecordTableOffset in
// memprof::MemProfVersion0 or the MemProf version number in
// memprof::MemProfVersion1 and above.
const uint64_t FirstWord =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);

memprof::IndexedVersion Version = memprof::Version0;
if (FirstWord == memprof::Version1 || FirstWord == memprof::Version2) {
// Everything is good. We can proceed to deserialize the rest.
Version = static_cast<memprof::IndexedVersion>(FirstWord);
} else if (FirstWord >= 24) {
// This is a heuristic/hack to detect memprof::MemProfVersion0,
// which does not have a version field in the header.
// In memprof::MemProfVersion0, FirstWord will be RecordTableOffset,
// which should be at least 24 because of the MemProf header size.
Version = memprof::Version0;
} else {
return make_error<InstrProfError>(
instrprof_error::unsupported_version,
formatv("MemProf version {} not supported; "
"requires version between {} and {}, inclusive",
FirstWord, memprof::MinimumSupportedVersion,
memprof::MaximumSupportedVersion));
}

// The value returned from RecordTableGenerator.Emit.
const uint64_t RecordTableOffset =
Version == memprof::Version0
? FirstWord
: support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
// The offset in the stream right before invoking
// FrameTableGenerator.Emit.
const uint64_t FramePayloadOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
// The value returned from FrameTableGenerator.Emit.
const uint64_t FrameTableOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);

// The offset in the stream right before invoking
// CallStackTableGenerator.Emit.
uint64_t CallStackPayloadOffset = 0;
// The value returned from CallStackTableGenerator.Emit.
uint64_t CallStackTableOffset = 0;
if (Version >= memprof::Version2) {
CallStackPayloadOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
CallStackTableOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
}

// Read the schema.
auto SchemaOr = memprof::readMemProfSchema(Ptr);
if (!SchemaOr)
return SchemaOr.takeError();
Schema = SchemaOr.get();

// Now initialize the table reader with a pointer into data buffer.
MemProfRecordTable.reset(MemProfRecordHashTable::Create(
/*Buckets=*/Start + RecordTableOffset,
/*Payload=*/Ptr,
/*Base=*/Start, memprof::RecordLookupTrait(Version, Schema)));

// Initialize the frame table reader with the payload and bucket offsets.
MemProfFrameTable.reset(MemProfFrameHashTable::Create(
/*Buckets=*/Start + FrameTableOffset,
/*Payload=*/Start + FramePayloadOffset,
/*Base=*/Start, memprof::FrameLookupTrait()));

if (Version >= memprof::Version2)
MemProfCallStackTable.reset(MemProfCallStackHashTable::Create(
/*Buckets=*/Start + CallStackTableOffset,
/*Payload=*/Start + CallStackPayloadOffset,
/*Base=*/Start, memprof::CallStackLookupTrait()));

#ifdef EXPENSIVE_CHECKS
// Go through all the records and verify that CSId has been correctly
// populated. Do this only under EXPENSIVE_CHECKS. Otherwise, we
// would defeat the purpose of OnDiskIterableChainedHashTable.
// Note that we can compare CSId against actual call stacks only for
// Version0 and Version1 because IndexedAllocationInfo::CallStack and
// IndexedMemProfRecord::CallSites are not populated in Version2.
if (Version <= memprof::Version1)
for (const auto &Record : MemProfRecordTable->data())
verifyIndexedMemProfRecord(Record);
#endif

return Error::success();
}

Error IndexedInstrProfReader::readHeader() {
using namespace support;

Expand Down Expand Up @@ -1244,95 +1337,8 @@ Error IndexedInstrProfReader::readHeader() {
uint64_t MemProfOffset =
endian::byte_swap<uint64_t, llvm::endianness::little>(
Header->MemProfOffset);

const unsigned char *Ptr = Start + MemProfOffset;

// Read the first 64-bit word, which may be RecordTableOffset in
// memprof::MemProfVersion0 or the MemProf version number in
// memprof::MemProfVersion1 and above.
const uint64_t FirstWord =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);

memprof::IndexedVersion Version = memprof::Version0;
if (FirstWord == memprof::Version1 || FirstWord == memprof::Version2) {
// Everything is good. We can proceed to deserialize the rest.
Version = static_cast<memprof::IndexedVersion>(FirstWord);
} else if (FirstWord >= 24) {
// This is a heuristic/hack to detect memprof::MemProfVersion0,
// which does not have a version field in the header.
// In memprof::MemProfVersion0, FirstWord will be RecordTableOffset,
// which should be at least 24 because of the MemProf header size.
Version = memprof::Version0;
} else {
return make_error<InstrProfError>(
instrprof_error::unsupported_version,
formatv("MemProf version {} not supported; "
"requires version between {} and {}, inclusive",
FirstWord, memprof::MinimumSupportedVersion,
memprof::MaximumSupportedVersion));
}

// The value returned from RecordTableGenerator.Emit.
const uint64_t RecordTableOffset =
Version == memprof::Version0
? FirstWord
: support::endian::readNext<uint64_t, llvm::endianness::little>(
Ptr);
// The offset in the stream right before invoking
// FrameTableGenerator.Emit.
const uint64_t FramePayloadOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
// The value returned from FrameTableGenerator.Emit.
const uint64_t FrameTableOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);

// The offset in the stream right before invoking
// CallStackTableGenerator.Emit.
uint64_t CallStackPayloadOffset = 0;
// The value returned from CallStackTableGenerator.Emit.
uint64_t CallStackTableOffset = 0;
if (Version >= memprof::Version2) {
CallStackPayloadOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
CallStackTableOffset =
support::endian::readNext<uint64_t, llvm::endianness::little>(Ptr);
}

// Read the schema.
auto SchemaOr = memprof::readMemProfSchema(Ptr);
if (!SchemaOr)
return SchemaOr.takeError();
Schema = SchemaOr.get();

// Now initialize the table reader with a pointer into data buffer.
MemProfRecordTable.reset(MemProfRecordHashTable::Create(
/*Buckets=*/Start + RecordTableOffset,
/*Payload=*/Ptr,
/*Base=*/Start, memprof::RecordLookupTrait(Version, Schema)));

// Initialize the frame table reader with the payload and bucket offsets.
MemProfFrameTable.reset(MemProfFrameHashTable::Create(
/*Buckets=*/Start + FrameTableOffset,
/*Payload=*/Start + FramePayloadOffset,
/*Base=*/Start, memprof::FrameLookupTrait()));

if (Version >= memprof::Version2)
MemProfCallStackTable.reset(MemProfCallStackHashTable::Create(
/*Buckets=*/Start + CallStackTableOffset,
/*Payload=*/Start + CallStackPayloadOffset,
/*Base=*/Start, memprof::CallStackLookupTrait()));

#ifdef EXPENSIVE_CHECKS
// Go through all the records and verify that CSId has been correctly
// populated. Do this only under EXPENSIVE_CHECKS. Otherwise, we
// would defeat the purpose of OnDiskIterableChainedHashTable.
// Note that we can compare CSId against actual call stacks only for
// Version0 and Version1 because IndexedAllocationInfo::CallStack and
// IndexedMemProfRecord::CallSites are not populated in Version2.
if (Version <= memprof::Version1)
for (const auto &Record : MemProfRecordTable->data())
verifyIndexedMemProfRecord(Record);
#endif
if (Error E = MemProfReader.deserialize(Start, MemProfOffset))
return E;
}

// BinaryIdOffset field in the header is only valid when the format version
Expand Down Expand Up @@ -1501,7 +1507,7 @@ Expected<InstrProfRecord> IndexedInstrProfReader::getInstrProfRecord(
}

Expected<memprof::MemProfRecord>
IndexedInstrProfReader::getMemProfRecord(const uint64_t FuncNameHash) {
IndexedMemProfReader::getMemProfRecord(const uint64_t FuncNameHash) const {
// TODO: Add memprof specific errors.
if (MemProfRecordTable == nullptr)
return make_error<InstrProfError>(instrprof_error::invalid_prof,
Expand Down