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[memprof] Add MemProf version (#86414)

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This patch adds a version field to the MemProf section of the indexed
profile format, calling the new version "version 1".  The existing
version is called "version 0".

The writer supports both versions via a command-line option:

  llvm-profdata merge --memprof-version=1 ...

The reader supports both versions by automatically detecting the
version from the header.
This commit is contained in:
Kazu Hirata
2024-03-28 14:29:34 -07:00
committed by GitHub
parent 17c3f102be
commit 44253a9ce6
5 changed files with 91 additions and 18 deletions
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11
llvm/include/llvm/ProfileData/InstrProfWriter.h
View File

@@ -75,11 +75,14 @@ private:
// deployment of newer versions of llvm-profdata.
bool WritePrevVersion = false;
// The MemProf version we should write.
memprof::IndexedVersion MemProfVersionRequested;
public:
InstrProfWriter(bool Sparse = false,
uint64_t TemporalProfTraceReservoirSize = 0,
uint64_t MaxTemporalProfTraceLength = 0,
bool WritePrevVersion = false);
InstrProfWriter(
bool Sparse = false, uint64_t TemporalProfTraceReservoirSize = 0,
uint64_t MaxTemporalProfTraceLength = 0, bool WritePrevVersion = false,
memprof::IndexedVersion MemProfVersionRequested = memprof::Version0);
~InstrProfWriter();
StringMap<ProfilingData> &getProfileData() { return FunctionData; }

14
llvm/include/llvm/ProfileData/MemProf.h
View File

@@ -16,6 +16,20 @@
namespace llvm {
namespace memprof {
// The versions of the indexed MemProf format
enum IndexedVersion : uint64_t {
// Version 0: This version didn't have a version field.
Version0 = 0,
// Version 1: Added a version field to the header.
Version1 = 1,
};
constexpr uint64_t MinimumSupportedVersion = Version0;
constexpr uint64_t MaximumSupportedVersion = Version1;
// Verify that the minimum and maximum satisfy the obvious constraint.
static_assert(MinimumSupportedVersion <= MaximumSupportedVersion);
enum class Meta : uint64_t {
Start = 0,
#define MIBEntryDef(NameTag, Name, Type) NameTag,

34
llvm/lib/ProfileData/InstrProfReader.cpp
View File

@@ -24,6 +24,7 @@
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SwapByteOrder.h"
#include "llvm/Support/VirtualFileSystem.h"
@@ -1230,10 +1231,39 @@ Error IndexedInstrProfReader::readHeader() {
Header->MemProfOffset);
const unsigned char *Ptr = Start + MemProfOffset;
// The value returned from RecordTableGenerator.Emit.
const uint64_t RecordTableOffset =
// Read the first 64-bit word, which may be RecordTableOffset in
// memprof::MemProfVersion0 or the MemProf version number in
// memprof::MemProfVersion1.
const uint64_t FirstWord =
support::endian::readNext<uint64_t, llvm::endianness::little,
unaligned>(Ptr);
memprof::IndexedVersion Version = memprof::Version0;
if (FirstWord == memprof::Version1) {
// Everything is good. We can proceed to deserialize the rest.
Version = memprof::Version1;
} 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,
unaligned>(Ptr);
// The offset in the stream right before invoking
// FrameTableGenerator.Emit.
const uint64_t FramePayloadOffset =

40
llvm/lib/ProfileData/InstrProfWriter.cpp
View File

@@ -22,6 +22,7 @@
#include "llvm/Support/Endian.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/OnDiskHashTable.h"
#include "llvm/Support/raw_ostream.h"
@@ -179,14 +180,15 @@ public:
} // end namespace llvm
InstrProfWriter::InstrProfWriter(bool Sparse,
uint64_t TemporalProfTraceReservoirSize,
uint64_t MaxTemporalProfTraceLength,
bool WritePrevVersion)
InstrProfWriter::InstrProfWriter(
bool Sparse, uint64_t TemporalProfTraceReservoirSize,
uint64_t MaxTemporalProfTraceLength, bool WritePrevVersion,
memprof::IndexedVersion MemProfVersionRequested)
: Sparse(Sparse), MaxTemporalProfTraceLength(MaxTemporalProfTraceLength),
TemporalProfTraceReservoirSize(TemporalProfTraceReservoirSize),
InfoObj(new InstrProfRecordWriterTrait()),
WritePrevVersion(WritePrevVersion) {}
WritePrevVersion(WritePrevVersion),
MemProfVersionRequested(MemProfVersionRequested) {}
InstrProfWriter::~InstrProfWriter() { delete InfoObj; }
@@ -516,6 +518,7 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
// Write the MemProf profile data if we have it. This includes a simple schema
// with the format described below followed by the hashtable:
// uint64_t Version
// uint64_t RecordTableOffset = RecordTableGenerator.Emit
// uint64_t FramePayloadOffset = Stream offset before emitting the frame table
// uint64_t FrameTableOffset = FrameTableGenerator.Emit
@@ -528,7 +531,21 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
// OnDiskChainedHashTable MemProfFrameData
uint64_t MemProfSectionStart = 0;
if (static_cast<bool>(ProfileKind & InstrProfKind::MemProf)) {
if (MemProfVersionRequested < memprof::MinimumSupportedVersion ||
MemProfVersionRequested > memprof::MaximumSupportedVersion) {
return make_error<InstrProfError>(
instrprof_error::unsupported_version,
formatv("MemProf version {} not supported; "
"requires version between {} and {}, inclusive",
MemProfVersionRequested, memprof::MinimumSupportedVersion,
memprof::MaximumSupportedVersion));
}
MemProfSectionStart = OS.tell();
if (MemProfVersionRequested >= memprof::Version1)
OS.write(MemProfVersionRequested);
OS.write(0ULL); // Reserve space for the memprof record table offset.
OS.write(0ULL); // Reserve space for the memprof frame payload offset.
OS.write(0ULL); // Reserve space for the memprof frame table offset.
@@ -570,12 +587,13 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
uint64_t FrameTableOffset = FrameTableGenerator.Emit(OS.OS, *FrameWriter);
PatchItem PatchItems[] = {
{MemProfSectionStart, &RecordTableOffset, 1},
{MemProfSectionStart + sizeof(uint64_t), &FramePayloadOffset, 1},
{MemProfSectionStart + 2 * sizeof(uint64_t), &FrameTableOffset, 1},
};
OS.patch(PatchItems);
uint64_t Header[] = {RecordTableOffset, FramePayloadOffset,
FrameTableOffset};
uint64_t HeaderUpdatePos = MemProfSectionStart;
if (MemProfVersionRequested >= memprof::Version1)
// The updates go just after the version field.
HeaderUpdatePos += sizeof(uint64_t);
OS.patch({{HeaderUpdatePos, Header, std::size(Header)}});
}
// BinaryIdSection has two parts:

10
llvm/tools/llvm-profdata/llvm-profdata.cpp
View File

@@ -300,6 +300,13 @@ cl::opt<bool> DoWritePrevVersion(
cl::desc("Write the previous version of indexed format, to enable "
"some forward compatibility."));
cl::opt<memprof::IndexedVersion> MemProfVersionRequested(
"memprof-version", cl::Hidden, cl::sub(MergeSubcommand),
cl::desc("Specify the version of the memprof format to use"),
cl::init(memprof::Version0),
cl::values(clEnumValN(memprof::Version0, "0", "version 0"),
clEnumValN(memprof::Version1, "1", "version 1")));
// Options specific to overlap subcommand.
cl::opt<std::string> BaseFilename(cl::Positional, cl::Required,
cl::desc("<base profile file>"),
@@ -588,7 +595,8 @@ struct WriterContext {
WriterContext(bool IsSparse, std::mutex &ErrLock,
SmallSet<instrprof_error, 4> &WriterErrorCodes,
uint64_t ReservoirSize = 0, uint64_t MaxTraceLength = 0)
: Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion),
: Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion,
MemProfVersionRequested),
ErrLock(ErrLock), WriterErrorCodes(WriterErrorCodes) {}
};