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
|
//===-- xray_inmemory_log.cc ------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of XRay, a dynamic runtime instrumentation system.
//
// Implementation of a simple in-memory log of XRay events. This defines a
// logging function that's compatible with the XRay handler interface, and
// routines for exporting data to files.
//
//===----------------------------------------------------------------------===//
#include <cassert>
#include <fcntl.h>
#include <mutex>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <thread>
#include <unistd.h>
#if defined(__x86_64__)
#include "xray_x86_64.h"
#elif defined(__arm__) || defined(__aarch64__)
#include "xray_emulate_tsc.h"
#else
#error "Unsupported CPU Architecture"
#endif /* Architecture-specific inline intrinsics */
#include "sanitizer_common/sanitizer_libc.h"
#include "xray/xray_records.h"
#include "xray_defs.h"
#include "xray_flags.h"
#include "xray_interface_internal.h"
#include "xray_utils.h"
// __xray_InMemoryRawLog will use a thread-local aligned buffer capped to a
// certain size (32kb by default) and use it as if it were a circular buffer for
// events. We store simple fixed-sized entries in the log for external analysis.
extern "C" {
void __xray_InMemoryRawLog(int32_t FuncId,
XRayEntryType Type) XRAY_NEVER_INSTRUMENT;
}
namespace __xray {
std::mutex LogMutex;
class ThreadExitFlusher {
int Fd;
XRayRecord *Start;
size_t &Offset;
public:
explicit ThreadExitFlusher(int Fd, XRayRecord *Start,
size_t &Offset) XRAY_NEVER_INSTRUMENT
: Fd(Fd),
Start(Start),
Offset(Offset) {}
~ThreadExitFlusher() XRAY_NEVER_INSTRUMENT {
std::lock_guard<std::mutex> L(LogMutex);
if (Fd > 0 && Start != nullptr) {
retryingWriteAll(Fd, reinterpret_cast<char *>(Start),
reinterpret_cast<char *>(Start + Offset));
// Because this thread's exit could be the last one trying to write to the
// file and that we're not able to close out the file properly, we sync
// instead and hope that the pending writes are flushed as the thread
// exits.
fsync(Fd);
}
}
};
} // namespace __xray
using namespace __xray;
static int __xray_OpenLogFile() XRAY_NEVER_INSTRUMENT {
int F = getLogFD();
auto CPUFrequency = getCPUFrequency();
if (F == -1)
return -1;
// Since we're here, we get to write the header. We set it up so that the
// header will only be written once, at the start, and let the threads
// logging do writes which just append.
XRayFileHeader Header;
Header.Version = 1;
Header.Type = FileTypes::NAIVE_LOG;
Header.CycleFrequency =
CPUFrequency == -1 ? 0 : static_cast<uint64_t>(CPUFrequency);
// FIXME: Actually check whether we have 'constant_tsc' and 'nonstop_tsc'
// before setting the values in the header.
Header.ConstantTSC = 1;
Header.NonstopTSC = 1;
retryingWriteAll(F, reinterpret_cast<char *>(&Header),
reinterpret_cast<char *>(&Header) + sizeof(Header));
return F;
}
void __xray_InMemoryRawLog(int32_t FuncId,
XRayEntryType Type) XRAY_NEVER_INSTRUMENT {
using Buffer =
std::aligned_storage<sizeof(XRayRecord), alignof(XRayRecord)>::type;
static constexpr size_t BuffLen = 1024;
thread_local static Buffer InMemoryBuffer[BuffLen] = {};
thread_local static size_t Offset = 0;
static int Fd = __xray_OpenLogFile();
if (Fd == -1)
return;
thread_local __xray::ThreadExitFlusher Flusher(
Fd, reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer), Offset);
thread_local pid_t TId = syscall(SYS_gettid);
// First we get the useful data, and stuff it into the already aligned buffer
// through a pointer offset.
auto &R = reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer)[Offset];
R.RecordType = RecordTypes::NORMAL;
R.TSC = __xray::readTSC(R.CPU);
R.TId = TId;
R.Type = Type;
R.FuncId = FuncId;
++Offset;
if (Offset == BuffLen) {
std::lock_guard<std::mutex> L(LogMutex);
auto RecordBuffer = reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer);
retryingWriteAll(Fd, reinterpret_cast<char *>(RecordBuffer),
reinterpret_cast<char *>(RecordBuffer + Offset));
Offset = 0;
}
}
static auto Unused = [] {
if (flags()->xray_naive_log)
__xray_set_handler(__xray_InMemoryRawLog);
return true;
}();
|
