llvm/bolt/include/bolt/Profile/DataAggregator.h

//===- bolt/Profile/DataAggregator.h - Perf data aggregator -----*- 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 family of functions reads profile data written by perf record,
// aggregates it and then writes it back to an output file.
//
//===----------------------------------------------------------------------===//

#ifndef BOLT_PROFILE_DATA_AGGREGATOR_H
#define BOLT_PROFILE_DATA_AGGREGATOR_H

#include "bolt/Profile/DataReader.h"
#include "bolt/Profile/YAMLProfileWriter.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Program.h"
#include <unordered_map>

namespace llvm {
namespace bolt {

class BinaryFunction;
class BinaryContext;
class BoltAddressTranslation;

/// DataAggregator inherits all parsing logic from DataReader as well as
/// its data structures used to represent aggregated profile data in memory.
///
/// The aggregator works by dispatching two separate perf-script jobs that
/// read perf samples and perf task annotations. Later, we read the output
/// files to extract information about which PID was used for this binary.
/// With the PID, we filter the samples and extract all LBR entries.
///
/// To aggregate LBR entries, we rely on a BinaryFunction map to locate the
/// original function where the event happened. Then, we convert a raw address
/// to an offset relative to the start of this function and aggregate branch
/// information for each function.
///
/// This must be coordinated with RewriteInstance so we have BinaryFunctions in
/// State::Disassembled. After this state, BinaryFunction will drop the
/// instruction map with original addresses we rely on to validate the traces
/// found in the LBR.
///
/// The last step is to write the aggregated data to disk in the output file
/// specified by the user.
class DataAggregator : public DataReader { … };
} // namespace bolt
} // namespace llvm

#endif