1//===- Profile.h - XRay Profile Abstraction -------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Defines the XRay Profile class representing the latency profile generated by
10// XRay's profiling mode.
11//
12//===----------------------------------------------------------------------===//
13#ifndef LLVM_XRAY_PROFILE_H
14#define LLVM_XRAY_PROFILE_H
15
16#include "llvm/ADT/DenseMap.h"
17#include "llvm/ADT/SmallVector.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/Error.h"
20#include <list>
21#include <utility>
22#include <vector>
23
24namespace llvm {
25namespace xray {
26
27class Profile;
28
29// We forward declare the Trace type for turning a Trace into a Profile.
30class Trace;
31
32/// This function will attempt to load an XRay Profiling Mode profile from the
33/// provided |Filename|.
34///
35/// For any errors encountered in the loading of the profile data from
36/// |Filename|, this function will return an Error condition appropriately.
37Expected<Profile> loadProfile(StringRef Filename);
38
39/// This algorithm will merge two Profile instances into a single Profile
40/// instance, aggregating blocks by Thread ID.
41Profile mergeProfilesByThread(const Profile &L, const Profile &R);
42
43/// This algorithm will merge two Profile instances into a single Profile
44/// instance, aggregating blocks by function call stack.
45Profile mergeProfilesByStack(const Profile &L, const Profile &R);
46
47/// This function takes a Trace and creates a Profile instance from it.
48Expected<Profile> profileFromTrace(const Trace &T);
49
50/// Profile instances are thread-compatible.
51class Profile {
52public:
53 using ThreadID = uint64_t;
54 using PathID = unsigned;
55 using FuncID = int32_t;
56
57 struct Data {
58 uint64_t CallCount;
59 uint64_t CumulativeLocalTime;
60 };
61
62 struct Block {
63 ThreadID Thread;
64 std::vector<std::pair<PathID, Data>> PathData;
65 };
66
67 /// Provides a sequence of function IDs from a previously interned PathID.
68 ///
69 /// Returns an error if |P| had not been interned before into the Profile.
70 ///
71 Expected<std::vector<FuncID>> expandPath(PathID P) const;
72
73 /// The stack represented in |P| must be in stack order (leaf to root). This
74 /// will always return the same PathID for |P| that has the same sequence.
75 PathID internPath(ArrayRef<FuncID> P);
76
77 /// Appends a fully-formed Block instance into the Profile.
78 ///
79 /// Returns an error condition in the following cases:
80 ///
81 /// - The PathData component of the Block is empty
82 ///
83 Error addBlock(Block &&B);
84
85 Profile() = default;
86 ~Profile() = default;
87
88 Profile(Profile &&O) noexcept
89 : Blocks(std::move(O.Blocks)), NodeStorage(std::move(O.NodeStorage)),
90 Roots(std::move(O.Roots)), PathIDMap(std::move(O.PathIDMap)),
91 NextID(O.NextID) {}
92
93 Profile &operator=(Profile &&O) noexcept {
94 Blocks = std::move(O.Blocks);
95 NodeStorage = std::move(O.NodeStorage);
96 Roots = std::move(O.Roots);
97 PathIDMap = std::move(O.PathIDMap);
98 NextID = O.NextID;
99 return *this;
100 }
101
102 Profile(const Profile &);
103 Profile &operator=(const Profile &);
104
105 friend void swap(Profile &L, Profile &R) {
106 using std::swap;
107 swap(x&: L.Blocks, y&: R.Blocks);
108 swap(x&: L.NodeStorage, y&: R.NodeStorage);
109 swap(LHS&: L.Roots, RHS&: R.Roots);
110 swap(a&: L.PathIDMap, b&: R.PathIDMap);
111 swap(a&: L.NextID, b&: R.NextID);
112 }
113
114private:
115 using BlockList = std::list<Block>;
116
117 struct TrieNode {
118 FuncID Func = 0;
119 std::vector<TrieNode *> Callees{};
120 TrieNode *Caller = nullptr;
121 PathID ID = 0;
122 };
123
124 // List of blocks associated with a Profile.
125 BlockList Blocks;
126
127 // List of TrieNode elements we've seen.
128 std::list<TrieNode> NodeStorage;
129
130 // List of call stack roots.
131 SmallVector<TrieNode *, 4> Roots;
132
133 // Reverse mapping between a PathID to a TrieNode*.
134 DenseMap<PathID, TrieNode *> PathIDMap;
135
136 // Used to identify paths.
137 PathID NextID = 1;
138
139public:
140 using const_iterator = BlockList::const_iterator;
141 const_iterator begin() const { return Blocks.begin(); }
142 const_iterator end() const { return Blocks.end(); }
143 bool empty() const { return Blocks.empty(); }
144};
145
146} // namespace xray
147} // namespace llvm
148
149#endif
150

source code of llvm/include/llvm/XRay/Profile.h