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//=-- InstrProfWriter.cpp - Instrumented profiling writer -------------------=//
//                     The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file contains support for writing profiling data for clang's
// instrumentation based PGO and coverage.

#include "llvm/ProfileData/InstrProfWriter.h"
#include "InstrProfIndexed.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/OnDiskHashTable.h"

using namespace llvm;

namespace {
class InstrProfRecordTrait {
  typedef StringRef key_type;
  typedef StringRef key_type_ref;

  typedef const InstrProfWriter::CounterData *const data_type;
  typedef const InstrProfWriter::CounterData *const data_type_ref;

  typedef uint64_t hash_value_type;
  typedef uint64_t offset_type;

  static hash_value_type ComputeHash(key_type_ref K) {
    return IndexedInstrProf::ComputeHash(IndexedInstrProf::HashType, K);

  static std::pair<offset_type, offset_type>
  EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
    using namespace llvm::support;
    endian::Writer<little> LE(Out);

    offset_type N = K.size();

    offset_type M = 0;
    for (const auto &Counts : *V)
      M += (2 + Counts.second.size()) * sizeof(uint64_t);

    return std::make_pair(N, M);

  static void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N){
    Out.write(K.data(), N);

  static void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V,
                       offset_type) {
    using namespace llvm::support;
    endian::Writer<little> LE(Out);

    for (const auto &Counts : *V) {
      for (uint64_t I : Counts.second)

InstrProfWriter::addFunctionCounts(StringRef FunctionName,
                                   uint64_t FunctionHash,
                                   ArrayRef<uint64_t> Counters) {
  auto &CounterData = FunctionData[FunctionName];

  auto Where = CounterData.find(FunctionHash);
  if (Where == CounterData.end()) {
    // We've never seen a function with this name and hash, add it.
    CounterData[FunctionHash] = Counters;
    // We keep track of the max function count as we go for simplicity.
    if (Counters[0] > MaxFunctionCount)
      MaxFunctionCount = Counters[0];
    return instrprof_error::success;

  // We're updating a function we've seen before.
  auto &FoundCounters = Where->second;
  // If the number of counters doesn't match we either have bad data or a hash
  // collision.
  if (FoundCounters.size() != Counters.size())
    return instrprof_error::count_mismatch;

  for (size_t I = 0, E = Counters.size(); I < E; ++I) {
    if (FoundCounters[I] + Counters[I] < FoundCounters[I])
      return instrprof_error::counter_overflow;
    FoundCounters[I] += Counters[I];
  // We keep track of the max function count as we go for simplicity.
  if (FoundCounters[0] > MaxFunctionCount)
    MaxFunctionCount = FoundCounters[0];

  return instrprof_error::success;

std::pair<uint64_t, uint64_t> InstrProfWriter::writeImpl(raw_ostream &OS) {
  OnDiskChainedHashTableGenerator<InstrProfRecordTrait> Generator;

  // Populate the hash table generator.
  for (const auto &I : FunctionData)
    Generator.insert(I.getKey(), &I.getValue());

  using namespace llvm::support;
  endian::Writer<little> LE(OS);

  // Write the header.

  // Save a space to write the hash table start location.
  uint64_t HashTableStartLoc = OS.tell();
  // Write the hash table.
  uint64_t HashTableStart = Generator.Emit(OS);

  return std::make_pair(HashTableStartLoc, HashTableStart);

void InstrProfWriter::write(raw_fd_ostream &OS) {
  // Write the hash table.
  auto TableStart = writeImpl(OS);

  // Go back and fill in the hash table start.
  using namespace support;

std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
  std::string Data;
  llvm::raw_string_ostream OS(Data);
  // Write the hash table.
  auto TableStart = writeImpl(OS);

  // Go back and fill in the hash table start.
  using namespace support;
  uint64_t Bytes = endian::byte_swap<uint64_t, little>(TableStart.second);
  Data.replace(TableStart.first, sizeof(uint64_t), (const char *)&Bytes,

  // Return this in an aligned memory buffer.
  return MemoryBuffer::getMemBufferCopy(Data);