Skip to content

Commit

Permalink
[PGO] Add support for writing previous indexed format (#84505)
Browse files Browse the repository at this point in the history 
Enable temporary support to ease use of new llvm-profdata with slightly
older indexed profiles after 16e74fd,
which bumped the indexed format for type profiling.
  • Loading branch information
@teresajohnson
teresajohnson committed Mar 8, 2024
1 parent 300a39b commit 08ddd2c
Show file tree
Hide file tree
Showing 4 changed files with 102 additions and 43 deletions.
10 changes: 9 additions & 1 deletion llvm/include/llvm/ProfileData/InstrProfWriter.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -68,10 +68,18 @@ class InstrProfWriter {
// Use raw pointer here for the incomplete type object.
InstrProfRecordWriterTrait *InfoObj;

// Temporary support for writing the previous version of the format, to enable
// some forward compatibility. Currently this suppresses the writing of the
// new vtable names section and header fields.
// TODO: Consider enabling this with future version changes as well, to ease
// deployment of newer versions of llvm-profdata.
bool WritePrevVersion = false;

public:
InstrProfWriter(bool Sparse = false,
uint64_t TemporalProfTraceReservoirSize = 0,
uint64_t MaxTemporalProfTraceLength = 0);
uint64_t MaxTemporalProfTraceLength = 0,
bool WritePrevVersion = false);
~InstrProfWriter();

StringMap<ProfilingData> &getProfileData() { return FunctionData; }
Expand Down
113 changes: 73 additions & 40 deletions llvm/lib/ProfileData/InstrProfWriter.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -181,10 +181,12 @@ class InstrProfRecordWriterTrait {

InstrProfWriter::InstrProfWriter(bool Sparse,
uint64_t TemporalProfTraceReservoirSize,
uint64_t MaxTemporalProfTraceLength)
uint64_t MaxTemporalProfTraceLength,
bool WritePrevVersion)
: Sparse(Sparse), MaxTemporalProfTraceLength(MaxTemporalProfTraceLength),
TemporalProfTraceReservoirSize(TemporalProfTraceReservoirSize),
InfoObj(new InstrProfRecordWriterTrait()) {}
InfoObj(new InstrProfRecordWriterTrait()),
WritePrevVersion(WritePrevVersion) {}

InstrProfWriter::~InstrProfWriter() { delete InfoObj; }

Expand Down Expand Up @@ -432,7 +434,13 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
// Write the header.
IndexedInstrProf::Header Header;
Header.Magic = IndexedInstrProf::Magic;
Header.Version = IndexedInstrProf::ProfVersion::CurrentVersion;
Header.Version = WritePrevVersion
? IndexedInstrProf::ProfVersion::Version11
: IndexedInstrProf::ProfVersion::CurrentVersion;
// The WritePrevVersion handling will either need to be removed or updated
// if the version is advanced beyond 12.
assert(IndexedInstrProf::ProfVersion::CurrentVersion ==
IndexedInstrProf::ProfVersion::Version12);
if (static_cast<bool>(ProfileKind & InstrProfKind::IRInstrumentation))
Header.Version |= VARIANT_MASK_IR_PROF;
if (static_cast<bool>(ProfileKind & InstrProfKind::ContextSensitive))
Expand Down Expand Up @@ -484,7 +492,8 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
OS.write(0);

uint64_t VTableNamesOffset = OS.tell();
OS.write(0);
if (!WritePrevVersion)
OS.write(0);

// Reserve space to write profile summary data.
uint32_t NumEntries = ProfileSummaryBuilder::DefaultCutoffs.size();
Expand Down Expand Up @@ -608,27 +617,29 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {

uint64_t VTableNamesSectionStart = OS.tell();

// Use a dummy (and uncompressed) string as compressed vtable names and get
// the necessary profile format change in place for version 12.
// TODO: Store the list of vtable names in InstrProfWriter and use the
// real compressed name.
std::string CompressedVTableNames = "VTableNames";
if (!WritePrevVersion) {
// Use a dummy (and uncompressed) string as compressed vtable names and get
// the necessary profile format change in place for version 12.
// TODO: Store the list of vtable names in InstrProfWriter and use the
// real compressed name.
std::string CompressedVTableNames = "VTableNames";

uint64_t CompressedStringLen = CompressedVTableNames.length();
uint64_t CompressedStringLen = CompressedVTableNames.length();

// Record the length of compressed string.
OS.write(CompressedStringLen);
// Record the length of compressed string.
OS.write(CompressedStringLen);

// Write the chars in compressed strings.
for (auto &c : CompressedVTableNames)
OS.writeByte(static_cast<uint8_t>(c));
// Write the chars in compressed strings.
for (auto &c : CompressedVTableNames)
OS.writeByte(static_cast<uint8_t>(c));

// Pad up to a multiple of 8.
// InstrProfReader would read bytes according to 'CompressedStringLen'.
uint64_t PaddedLength = alignTo(CompressedStringLen, 8);
// Pad up to a multiple of 8.
// InstrProfReader would read bytes according to 'CompressedStringLen'.
uint64_t PaddedLength = alignTo(CompressedStringLen, 8);

for (uint64_t K = CompressedStringLen; K < PaddedLength; K++) {
OS.writeByte(0);
for (uint64_t K = CompressedStringLen; K < PaddedLength; K++) {
OS.writeByte(0);
}
}

uint64_t TemporalProfTracesSectionStart = 0;
Expand Down Expand Up @@ -662,26 +673,48 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
}
InfoObj->CSSummaryBuilder = nullptr;

// Now do the final patch:
PatchItem PatchItems[] = {
// Patch the Header.HashOffset field.
{HashTableStartFieldOffset, &HashTableStart, 1},
// Patch the Header.MemProfOffset (=0 for profiles without MemProf
// data).
{MemProfSectionOffset, &MemProfSectionStart, 1},
// Patch the Header.BinaryIdSectionOffset.
{BinaryIdSectionOffset, &BinaryIdSectionStart, 1},
// Patch the Header.TemporalProfTracesOffset (=0 for profiles without
// traces).
{TemporalProfTracesOffset, &TemporalProfTracesSectionStart, 1},
{VTableNamesOffset, &VTableNamesSectionStart, 1},
// Patch the summary data.
{SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
(int)(SummarySize / sizeof(uint64_t))},
{CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
(int)CSSummarySize}};

OS.patch(PatchItems, std::size(PatchItems));
if (!WritePrevVersion) {
// Now do the final patch:
PatchItem PatchItems[] = {
// Patch the Header.HashOffset field.
{HashTableStartFieldOffset, &HashTableStart, 1},
// Patch the Header.MemProfOffset (=0 for profiles without MemProf
// data).
{MemProfSectionOffset, &MemProfSectionStart, 1},
// Patch the Header.BinaryIdSectionOffset.
{BinaryIdSectionOffset, &BinaryIdSectionStart, 1},
// Patch the Header.TemporalProfTracesOffset (=0 for profiles without
// traces).
{TemporalProfTracesOffset, &TemporalProfTracesSectionStart, 1},
{VTableNamesOffset, &VTableNamesSectionStart, 1},
// Patch the summary data.
{SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
(int)(SummarySize / sizeof(uint64_t))},
{CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
(int)CSSummarySize}};

OS.patch(PatchItems, std::size(PatchItems));
} else {
// Now do the final patch:
PatchItem PatchItems[] = {
// Patch the Header.HashOffset field.
{HashTableStartFieldOffset, &HashTableStart, 1},
// Patch the Header.MemProfOffset (=0 for profiles without MemProf
// data).
{MemProfSectionOffset, &MemProfSectionStart, 1},
// Patch the Header.BinaryIdSectionOffset.
{BinaryIdSectionOffset, &BinaryIdSectionStart, 1},
// Patch the Header.TemporalProfTracesOffset (=0 for profiles without
// traces).
{TemporalProfTracesOffset, &TemporalProfTracesSectionStart, 1},
// Patch the summary data.
{SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
(int)(SummarySize / sizeof(uint64_t))},
{CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
(int)CSSummarySize}};

OS.patch(PatchItems, std::size(PatchItems));
}

for (const auto &I : FunctionData)
for (const auto &F : I.getValue())
Expand Down
9 changes: 9 additions & 0 deletions llvm/test/tools/llvm-profdata/profile-version.test
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
Test the profile version.

RUN: llvm-profdata merge -o %t.profdata %p/Inputs/basic.proftext
RUN: llvm-profdata show --profile-version %t.profdata | FileCheck %s
CHECK: Profile version: 12

RUN: llvm-profdata merge -o %t.prev.profdata %p/Inputs/basic.proftext --write-prev-version
RUN: llvm-profdata show --profile-version %t.prev.profdata | FileCheck %s --check-prefix=PREV
PREV: Profile version: 11
13 changes: 11 additions & 2 deletions llvm/tools/llvm-profdata/llvm-profdata.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -291,6 +291,15 @@ cl::opt<bool> DropProfileSymbolList(
cl::desc("Drop the profile symbol list when merging AutoFDO profiles "
"(only meaningful for -sample)"));

// Temporary support for writing the previous version of the format, to enable
// some forward compatibility.
// TODO: Consider enabling this with future version changes as well, to ease
// deployment of newer versions of llvm-profdata.
cl::opt<bool> DoWritePrevVersion(
"write-prev-version", cl::init(false), cl::Hidden,
cl::desc("Write the previous version of indexed format, to enable "
"some forward compatibility."));

// Options specific to overlap subcommand.
cl::opt<std::string> BaseFilename(cl::Positional, cl::Required,
cl::desc("<base profile file>"),
Expand Down Expand Up @@ -579,8 +588,8 @@ 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), ErrLock(ErrLock),
WriterErrorCodes(WriterErrorCodes) {}
: Writer(IsSparse, ReservoirSize, MaxTraceLength, DoWritePrevVersion),
ErrLock(ErrLock), WriterErrorCodes(WriterErrorCodes) {}
};

/// Computer the overlap b/w profile BaseFilename and TestFileName,
Expand Down

0 comments on commit 08ddd2c

Please sign in to comment.