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//===- InstrProfCorrelator.h ------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
// This file defines InstrProfCorrelator used to generate PGO profiles from
// raw profile data and debug info.
//===----------------------------------------------------------------------===//
#ifndef LLVM_PROFILEDATA_INSTRPROFCORRELATOR_H
#define LLVM_PROFILEDATA_INSTRPROFCORRELATOR_H
#include "llvm/ADT/DenseSet.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MemoryBuffer.h"
#include <vector>
namespace llvm {
/// InstrProfCorrelator - A base class used to create raw instrumentation data
/// to their functions.
class InstrProfCorrelator {
public:
static llvm::Expected<std::unique_ptr<InstrProfCorrelator>>
get(StringRef DebugInfoFilename);
/// Construct a ProfileData vector used to correlate raw instrumentation data
/// to their functions.
virtual Error correlateProfileData() = 0;
/// Return the number of ProfileData elements.
llvm::Optional<size_t> getDataSize() const;
/// Return a pointer to the names string that this class constructs.
const char *getNamesPointer() const { return Names.c_str(); }
/// Return the number of bytes in the names string.
size_t getNamesSize() const { return Names.size(); }
/// Return the size of the counters section in bytes.
uint64_t getCountersSectionSize() const {
return Ctx->CountersSectionEnd - Ctx->CountersSectionStart;
}
static const char *FunctionNameAttributeName;
static const char *CFGHashAttributeName;
static const char *NumCountersAttributeName;
enum InstrProfCorrelatorKind { CK_32Bit, CK_64Bit };
InstrProfCorrelatorKind getKind() const { return Kind; }
virtual ~InstrProfCorrelator() = default;
protected:
struct Context {
static llvm::Expected<std::unique_ptr<Context>>
get(std::unique_ptr<MemoryBuffer> Buffer, const object::ObjectFile &Obj);
std::unique_ptr<MemoryBuffer> Buffer;
/// The address range of the __llvm_prf_cnts section.
uint64_t CountersSectionStart;
uint64_t CountersSectionEnd;
/// True if target and host have different endian orders.
bool ShouldSwapBytes;
};
const std::unique_ptr<InstrProfCorrelator::Context> Ctx;
InstrProfCorrelator(InstrProfCorrelatorKind K, std::unique_ptr<Context> Ctx)
: Ctx(std::move(Ctx)), Kind(K) {}
std::string Names;
std::vector<std::string> NamesVec;
private:
static llvm::Expected<std::unique_ptr<InstrProfCorrelator>>
get(std::unique_ptr<MemoryBuffer> Buffer);
const InstrProfCorrelatorKind Kind;
};
/// InstrProfCorrelatorImpl - A child of InstrProfCorrelator with a template
/// pointer type so that the ProfileData vector can be materialized.
template <class IntPtrT>
class InstrProfCorrelatorImpl : public InstrProfCorrelator {
public:
InstrProfCorrelatorImpl(std::unique_ptr<InstrProfCorrelator::Context> Ctx);
static bool classof(const InstrProfCorrelator *C);
/// Return a pointer to the underlying ProfileData vector that this class
/// constructs.
const RawInstrProf::ProfileData<IntPtrT> *getDataPointer() const {
return Data.empty() ? nullptr : Data.data();
}
/// Return the number of ProfileData elements.
size_t getDataSize() const { return Data.size(); }
static llvm::Expected<std::unique_ptr<InstrProfCorrelatorImpl<IntPtrT>>>
get(std::unique_ptr<InstrProfCorrelator::Context> Ctx,
const object::ObjectFile &Obj);
protected:
std::vector<RawInstrProf::ProfileData<IntPtrT>> Data;
Error correlateProfileData() override;
virtual void correlateProfileDataImpl() = 0;
void addProbe(StringRef FunctionName, uint64_t CFGHash, IntPtrT CounterOffset,
IntPtrT FunctionPtr, uint32_t NumCounters);
private:
InstrProfCorrelatorImpl(InstrProfCorrelatorKind Kind,
std::unique_ptr<InstrProfCorrelator::Context> Ctx)
: InstrProfCorrelator(Kind, std::move(Ctx)){};
llvm::DenseSet<IntPtrT> CounterOffsets;
// Byte-swap the value if necessary.
template <class T> T maybeSwap(T Value) const {
return Ctx->ShouldSwapBytes ? sys::getSwappedBytes(Value) : Value;
}
};
/// DwarfInstrProfCorrelator - A child of InstrProfCorrelatorImpl that takes
/// DWARF debug info as input to correlate profiles.
template <class IntPtrT>
class DwarfInstrProfCorrelator : public InstrProfCorrelatorImpl<IntPtrT> {
public:
DwarfInstrProfCorrelator(std::unique_ptr<DWARFContext> DICtx,
std::unique_ptr<InstrProfCorrelator::Context> Ctx)
: InstrProfCorrelatorImpl<IntPtrT>(std::move(Ctx)),
DICtx(std::move(DICtx)) {}
private:
std::unique_ptr<DWARFContext> DICtx;
/// Return the address of the object that the provided DIE symbolizes.
llvm::Optional<uint64_t> getLocation(const DWARFDie &Die) const;
/// Returns true if the provided DIE symbolizes an instrumentation probe
/// symbol.
static bool isDIEOfProbe(const DWARFDie &Die);
/// Iterate over DWARF DIEs to find those that symbolize instrumentation
/// probes and construct the ProfileData vector and Names string.
///
/// Here is some example DWARF for an instrumentation probe we are looking
/// for:
/// \code
/// DW_TAG_subprogram
/// DW_AT_low_pc (0x0000000000000000)
/// DW_AT_high_pc (0x0000000000000014)
/// DW_AT_name ("foo")
/// DW_TAG_variable
/// DW_AT_name ("__profc_foo")
/// DW_AT_location (DW_OP_addr 0x0)
/// DW_TAG_LLVM_annotation
/// DW_AT_name ("Function Name")
/// DW_AT_const_value ("foo")
/// DW_TAG_LLVM_annotation
/// DW_AT_name ("CFG Hash")
/// DW_AT_const_value (12345678)
/// DW_TAG_LLVM_annotation
/// DW_AT_name ("Num Counters")
/// DW_AT_const_value (2)
/// NULL
/// NULL
/// \endcode
void correlateProfileDataImpl() override;
};
} // end namespace llvm
#endif // LLVM_PROFILEDATA_INSTRPROFCORRELATOR_H
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