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//===- PGOCtxProfReader.cpp - Contextual Instrumentation profile reader ---===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Read a contextual profile into a datastructure suitable for maintenance
// throughout IPO
//
//===----------------------------------------------------------------------===//
#include "llvm/ProfileData/PGOCtxProfReader.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Bitstream/BitCodeEnums.h"
#include "llvm/Bitstream/BitstreamReader.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/ProfileData/PGOCtxProfWriter.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"
using namespace llvm;
// FIXME(#92054) - these Error handling macros are (re-)invented in a few
// places.
#define EXPECT_OR_RET(LHS, RHS) \
auto LHS = RHS; \
if (!LHS) \
return LHS.takeError();
#define RET_ON_ERR(EXPR) \
if (auto Err = (EXPR)) \
return Err;
Expected<PGOCtxProfContext &>
PGOCtxProfContext::getOrEmplace(uint32_t Index, GlobalValue::GUID G,
SmallVectorImpl<uint64_t> &&Counters) {
auto [Iter, Inserted] =
Callsites[Index].insert({G, PGOCtxProfContext(G, std::move(Counters))});
if (!Inserted)
return make_error<InstrProfError>(instrprof_error::invalid_prof,
"Duplicate GUID for same callsite.");
return Iter->second;
}
Expected<BitstreamEntry> PGOCtxProfileReader::advance() {
return Cursor.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
}
Error PGOCtxProfileReader::wrongValue(const Twine &Msg) {
return make_error<InstrProfError>(instrprof_error::invalid_prof, Msg);
}
Error PGOCtxProfileReader::unsupported(const Twine &Msg) {
return make_error<InstrProfError>(instrprof_error::unsupported_version, Msg);
}
bool PGOCtxProfileReader::canReadContext() {
auto Blk = advance();
if (!Blk) {
consumeError(Blk.takeError());
return false;
}
return Blk->Kind == BitstreamEntry::SubBlock &&
Blk->ID == PGOCtxProfileBlockIDs::ContextNodeBlockID;
}
Expected<std::pair<std::optional<uint32_t>, PGOCtxProfContext>>
PGOCtxProfileReader::readContext(bool ExpectIndex) {
RET_ON_ERR(Cursor.EnterSubBlock(PGOCtxProfileBlockIDs::ContextNodeBlockID));
std::optional<ctx_profile::GUID> Guid;
std::optional<SmallVector<uint64_t, 16>> Counters;
std::optional<uint32_t> CallsiteIndex;
SmallVector<uint64_t, 1> RecordValues;
// We don't prescribe the order in which the records come in, and we are ok
// if other unsupported records appear. We seek in the current subblock until
// we get all we know.
auto GotAllWeNeed = [&]() {
return Guid.has_value() && Counters.has_value() &&
(!ExpectIndex || CallsiteIndex.has_value());
};
while (!GotAllWeNeed()) {
RecordValues.clear();
EXPECT_OR_RET(Entry, advance());
if (Entry->Kind != BitstreamEntry::Record)
return wrongValue(
"Expected records before encountering more subcontexts");
EXPECT_OR_RET(ReadRecord,
Cursor.readRecord(bitc::UNABBREV_RECORD, RecordValues));
switch (*ReadRecord) {
case PGOCtxProfileRecords::Guid:
if (RecordValues.size() != 1)
return wrongValue("The GUID record should have exactly one value");
Guid = RecordValues[0];
break;
case PGOCtxProfileRecords::Counters:
Counters = std::move(RecordValues);
if (Counters->empty())
return wrongValue("Empty counters. At least the entry counter (one "
"value) was expected");
break;
case PGOCtxProfileRecords::CalleeIndex:
if (!ExpectIndex)
return wrongValue("The root context should not have a callee index");
if (RecordValues.size() != 1)
return wrongValue("The callee index should have exactly one value");
CallsiteIndex = RecordValues[0];
break;
default:
// OK if we see records we do not understand, like records (profile
// components) introduced later.
break;
}
}
PGOCtxProfContext Ret(*Guid, std::move(*Counters));
while (canReadContext()) {
EXPECT_OR_RET(SC, readContext(true));
auto &Targets = Ret.callsites()[*SC->first];
auto [_, Inserted] =
Targets.insert({SC->second.guid(), std::move(SC->second)});
if (!Inserted)
return wrongValue(
"Unexpected duplicate target (callee) at the same callsite.");
}
return std::make_pair(CallsiteIndex, std::move(Ret));
}
Error PGOCtxProfileReader::readMetadata() {
if (Magic.size() < PGOCtxProfileWriter::ContainerMagic.size() ||
Magic != PGOCtxProfileWriter::ContainerMagic)
return make_error<InstrProfError>(instrprof_error::invalid_prof,
"Invalid magic");
BitstreamEntry Entry;
RET_ON_ERR(Cursor.advance().moveInto(Entry));
if (Entry.Kind != BitstreamEntry::SubBlock ||
Entry.ID != bitc::BLOCKINFO_BLOCK_ID)
return unsupported("Expected Block ID");
// We don't need the blockinfo to read the rest, it's metadata usable for e.g.
// llvm-bcanalyzer.
RET_ON_ERR(Cursor.SkipBlock());
EXPECT_OR_RET(Blk, advance());
if (Blk->Kind != BitstreamEntry::SubBlock)
return unsupported("Expected Version record");
RET_ON_ERR(
Cursor.EnterSubBlock(PGOCtxProfileBlockIDs::ProfileMetadataBlockID));
EXPECT_OR_RET(MData, advance());
if (MData->Kind != BitstreamEntry::Record)
return unsupported("Expected Version record");
SmallVector<uint64_t, 1> Ver;
EXPECT_OR_RET(Code, Cursor.readRecord(bitc::UNABBREV_RECORD, Ver));
if (*Code != PGOCtxProfileRecords::Version)
return unsupported("Expected Version record");
if (Ver.size() != 1 || Ver[0] > PGOCtxProfileWriter::CurrentVersion)
return unsupported("Version " + Twine(*Code) +
" is higher than supported version " +
Twine(PGOCtxProfileWriter::CurrentVersion));
return Error::success();
}
Expected<std::map<GlobalValue::GUID, PGOCtxProfContext>>
PGOCtxProfileReader::loadContexts() {
std::map<GlobalValue::GUID, PGOCtxProfContext> Ret;
RET_ON_ERR(readMetadata());
while (canReadContext()) {
EXPECT_OR_RET(E, readContext(false));
auto Key = E->second.guid();
if (!Ret.insert({Key, std::move(E->second)}).second)
return wrongValue("Duplicate roots");
}
return std::move(Ret);
}
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