reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
//===- Profile.h - XRay Profile Abstraction -------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Defines the XRay Profile class representing the latency profile generated by
// XRay's profiling mode.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_XRAY_PROFILE_H
#define LLVM_XRAY_PROFILE_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Error.h"
#include <list>
#include <utility>
#include <vector>

namespace llvm {
namespace xray {

class Profile;

// We forward declare the Trace type for turning a Trace into a Profile.
class Trace;

/// This function will attempt to load an XRay Profiling Mode profile from the
/// provided |Filename|.
///
/// For any errors encountered in the loading of the profile data from
/// |Filename|, this function will return an Error condition appropriately.
Expected<Profile> loadProfile(StringRef Filename);

/// This algorithm will merge two Profile instances into a single Profile
/// instance, aggregating blocks by Thread ID.
Profile mergeProfilesByThread(const Profile &L, const Profile &R);

/// This algorithm will merge two Profile instances into a single Profile
/// instance, aggregating blocks by function call stack.
Profile mergeProfilesByStack(const Profile &L, const Profile &R);

/// This function takes a Trace and creates a Profile instance from it.
Expected<Profile> profileFromTrace(const Trace &T);

/// Profile instances are thread-compatible.
class Profile {
public:
  using ThreadID = uint64_t;
  using PathID = unsigned;
  using FuncID = int32_t;

  struct Data {
    uint64_t CallCount;
    uint64_t CumulativeLocalTime;
  };

  struct Block {
    ThreadID Thread;
    std::vector<std::pair<PathID, Data>> PathData;
  };

  /// Provides a sequence of function IDs from a previously interned PathID.
  ///
  /// Returns an error if |P| had not been interned before into the Profile.
  ///
  Expected<std::vector<FuncID>> expandPath(PathID P) const;

  /// The stack represented in |P| must be in stack order (leaf to root). This
  /// will always return the same PathID for |P| that has the same sequence.
  PathID internPath(ArrayRef<FuncID> P);

  /// Appends a fully-formed Block instance into the Profile.
  ///
  /// Returns an error condition in the following cases:
  ///
  ///    - The PathData component of the Block is empty
  ///
  Error addBlock(Block &&B);

  Profile() = default;
  ~Profile() = default;

  Profile(Profile &&O) noexcept
      : Blocks(std::move(O.Blocks)), NodeStorage(std::move(O.NodeStorage)),
        Roots(std::move(O.Roots)), PathIDMap(std::move(O.PathIDMap)),
        NextID(O.NextID) {}

  Profile &operator=(Profile &&O) noexcept {
    Blocks = std::move(O.Blocks);
    NodeStorage = std::move(O.NodeStorage);
    Roots = std::move(O.Roots);
    PathIDMap = std::move(O.PathIDMap);
    NextID = O.NextID;
    return *this;
  }

  Profile(const Profile &);
  Profile &operator=(const Profile &);

  friend void swap(Profile &L, Profile &R) {
    using std::swap;
    swap(L.Blocks, R.Blocks);
    swap(L.NodeStorage, R.NodeStorage);
    swap(L.Roots, R.Roots);
    swap(L.PathIDMap, R.PathIDMap);
    swap(L.NextID, R.NextID);
  }

private:
  using BlockList = std::list<Block>;

  struct TrieNode {
    FuncID Func = 0;
    std::vector<TrieNode *> Callees{};
    TrieNode *Caller = nullptr;
    PathID ID = 0;
  };

  // List of blocks associated with a Profile.
  BlockList Blocks;

  // List of TrieNode elements we've seen.
  std::list<TrieNode> NodeStorage;

  // List of call stack roots.
  SmallVector<TrieNode *, 4> Roots;

  // Reverse mapping between a PathID to a TrieNode*.
  DenseMap<PathID, TrieNode *> PathIDMap;

  // Used to identify paths.
  PathID NextID = 1;

public:
  using const_iterator = BlockList::const_iterator;
  const_iterator begin() const { return Blocks.begin(); }
  const_iterator end() const { return Blocks.end(); }
  bool empty() const { return Blocks.empty(); }
};

} // namespace xray
} // namespace llvm

#endif