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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef __PROFILER_BACKTRACE_H
#define __PROFILER_BACKTRACE_H
#include "ProfileBuffer.h"
#include "mozilla/ProfileBufferEntrySerialization.h"
#include "mozilla/UniquePtrExtensions.h"
#include <string>
class ProfileBuffer;
class ProfilerCodeAddressService;
class ThreadInfo;
class UniqueStacks;
namespace mozilla {
class ProfileChunkedBuffer;
class TimeStamp;
namespace baseprofiler {
class SpliceableJSONWriter;
} // namespace baseprofiler
} // namespace mozilla
// ProfilerBacktrace encapsulates a synchronous sample.
// It can work with a ProfileBuffer and/or a ProfileChunkedBuffer (if both, they
// must already be linked together). The ProfileChunkedBuffer contains all the
// data; the ProfileBuffer is not strictly needed, only provide it if it is
// already available at the call site.
// And these buffers can either be:
// - owned here, so that the ProfilerBacktrace object can be kept for later
// use), OR
// - referenced through pointers (in cases where the backtrace is immediately
// streamed out, so we only need temporary references to external buffers);
// these pointers may be null for empty backtraces.
class ProfilerBacktrace {
public:
// Take ownership of external buffers and use them to keep, and to stream a
// backtrace. If a ProfileBuffer is given, its underlying chunked buffer must
// be provided as well.
explicit ProfilerBacktrace(
const char* aName,
mozilla::UniquePtr<mozilla::ProfileChunkedBuffer>
aProfileChunkedBufferStorage,
mozilla::UniquePtr<ProfileBuffer> aProfileBufferStorageOrNull = nullptr);
// Take pointers to external buffers and use them to stream a backtrace.
// If null, the backtrace is effectively empty.
// If both are provided, they must already be connected.
explicit ProfilerBacktrace(
const char* aName,
mozilla::ProfileChunkedBuffer* aExternalProfileChunkedBufferOrNull =
nullptr,
ProfileBuffer* aExternalProfileBufferOrNull = nullptr);
~ProfilerBacktrace();
[[nodiscard]] bool IsEmpty() const {
return !mProfileChunkedBuffer ||
mozilla::ProfileBufferEntryWriter::Serializer<
mozilla::ProfileChunkedBuffer>::Bytes(*mProfileChunkedBuffer) <=
mozilla::ULEB128Size(0u);
}
// ProfilerBacktraces' stacks are deduplicated in the context of the
// profile that contains the backtrace as a marker payload.
//
// That is, markers that contain backtraces should not need their own stack,
// frame, and string tables. They should instead reuse their parent
// profile's tables.
ProfilerThreadId StreamJSON(
mozilla::baseprofiler::SpliceableJSONWriter& aWriter,
const mozilla::TimeStamp& aProcessStartTime, UniqueStacks& aUniqueStacks);
private:
// Used to serialize a ProfilerBacktrace.
friend struct mozilla::ProfileBufferEntryWriter::Serializer<
ProfilerBacktrace>;
friend struct mozilla::ProfileBufferEntryReader::Deserializer<
ProfilerBacktrace>;
std::string mName;
// `ProfileChunkedBuffer` in which `mProfileBuffer` stores its data; must be
// located before `mProfileBuffer` so that it's destroyed after.
mozilla::UniquePtr<mozilla::ProfileChunkedBuffer>
mOptionalProfileChunkedBufferStorage;
// If null, there is no need to check mProfileBuffer's (if present) underlying
// buffer because this is done when constructed.
mozilla::ProfileChunkedBuffer* mProfileChunkedBuffer;
mozilla::UniquePtr<ProfileBuffer> mOptionalProfileBufferStorage;
ProfileBuffer* mProfileBuffer;
};
namespace mozilla {
// Format: [ UniquePtr<BlockRingsBuffer> | name ]
// Initial len==0 marks a nullptr or empty backtrace.
template <>
struct mozilla::ProfileBufferEntryWriter::Serializer<ProfilerBacktrace> {
static Length Bytes(const ProfilerBacktrace& aBacktrace) {
if (!aBacktrace.mProfileChunkedBuffer) {
// No buffer.
return ULEB128Size(0u);
}
auto bufferBytes = SumBytes(*aBacktrace.mProfileChunkedBuffer);
if (bufferBytes <= ULEB128Size(0u)) {
// Empty buffer.
return ULEB128Size(0u);
}
return bufferBytes + SumBytes(aBacktrace.mName);
}
static void Write(mozilla::ProfileBufferEntryWriter& aEW,
const ProfilerBacktrace& aBacktrace) {
if (!aBacktrace.mProfileChunkedBuffer ||
SumBytes(*aBacktrace.mProfileChunkedBuffer) <= ULEB128Size(0u)) {
// No buffer, or empty buffer.
aEW.WriteULEB128(0u);
return;
}
aEW.WriteObject(*aBacktrace.mProfileChunkedBuffer);
aEW.WriteObject(aBacktrace.mName);
}
};
template <typename Destructor>
struct mozilla::ProfileBufferEntryWriter::Serializer<
mozilla::UniquePtr<ProfilerBacktrace, Destructor>> {
static Length Bytes(
const mozilla::UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
if (!aBacktrace) {
// Null backtrace pointer (treated like an empty backtrace).
return ULEB128Size(0u);
}
return SumBytes(*aBacktrace);
}
static void Write(
mozilla::ProfileBufferEntryWriter& aEW,
const mozilla::UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
if (!aBacktrace) {
// Null backtrace pointer (treated like an empty backtrace).
aEW.WriteULEB128(0u);
return;
}
aEW.WriteObject(*aBacktrace);
}
};
template <typename Destructor>
struct mozilla::ProfileBufferEntryReader::Deserializer<
mozilla::UniquePtr<ProfilerBacktrace, Destructor>> {
static void ReadInto(
mozilla::ProfileBufferEntryReader& aER,
mozilla::UniquePtr<ProfilerBacktrace, Destructor>& aBacktrace) {
aBacktrace = Read(aER);
}
static mozilla::UniquePtr<ProfilerBacktrace, Destructor> Read(
mozilla::ProfileBufferEntryReader& aER) {
auto profileChunkedBuffer =
aER.ReadObject<UniquePtr<ProfileChunkedBuffer>>();
if (!profileChunkedBuffer) {
return nullptr;
}
MOZ_ASSERT(
!profileChunkedBuffer->IsThreadSafe(),
"ProfilerBacktrace only stores non-thread-safe ProfileChunkedBuffers");
std::string name = aER.ReadObject<std::string>();
return UniquePtr<ProfilerBacktrace, Destructor>{
new ProfilerBacktrace(name.c_str(), std::move(profileChunkedBuffer))};
}
};
} // namespace mozilla
#endif // __PROFILER_BACKTRACE_H
|
