Revision control

Line Code
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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/* -*- Mode: C++; tab-width: 8; 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/. */

#include <unistd.h>
#include <sys/mman.h>
#include <mach/mach_init.h>
#include <mach-o/getsect.h>

#include <AvailabilityMacros.h>

#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <libkern/OSAtomic.h>
#include <mach/mach.h>
#include <mach/semaphore.h>
#include <mach/task.h>
#include <mach/thread_act.h>
#include <mach/vm_statistics.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <math.h>

// this port is based off of v8 svn revision 9837

/* static */ int
Thread::GetCurrentId()
{
  return gettid();
}

void*
GetStackTop(void* aGuess)
{
  pthread_t thread = pthread_self();
  return pthread_get_stackaddr_np(thread);
}

class PlatformData
{
public:
  explicit PlatformData(int aThreadId) : mProfiledThread(mach_thread_self())
  {
    MOZ_COUNT_CTOR(PlatformData);
  }

  ~PlatformData() {
    // Deallocate Mach port for thread.
    mach_port_deallocate(mach_task_self(), mProfiledThread);

    MOZ_COUNT_DTOR(PlatformData);
  }

  thread_act_t ProfiledThread() { return mProfiledThread; }

private:
  // Note: for mProfiledThread Mach primitives are used instead of pthread's
  // because the latter doesn't provide thread manipulation primitives required.
  // For details, consult "Mac OS X Internals" book, Section 7.3.
  thread_act_t mProfiledThread;
};

////////////////////////////////////////////////////////////////////////
// BEGIN Sampler target specifics

Sampler::Sampler(PSLockRef aLock)
{
}

void
Sampler::Disable(PSLockRef aLock)
{
}

template<typename Func>
void
Sampler::SuspendAndSampleAndResumeThread(PSLockRef aLock,
                                         const RegisteredThread& aRegisteredThread,
                                         const Func& aProcessRegs)
{
  thread_act_t samplee_thread =
    aRegisteredThread.GetPlatformData()->ProfiledThread();

  //----------------------------------------------------------------//
  // Suspend the samplee thread and get its context.

  // We're using thread_suspend on OS X because pthread_kill (which is what we
  // at one time used on Linux) has less consistent performance and causes
  // strange crashes, see bug 1166778 and bug 1166808.  thread_suspend
  // is also just a lot simpler to use.

  if (KERN_SUCCESS != thread_suspend(samplee_thread)) {
    return;
  }

  //----------------------------------------------------------------//
  // Sample the target thread.

  // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  //
  // The profiler's "critical section" begins here.  We must be very careful
  // what we do here, or risk deadlock.  See the corresponding comment in
  // platform-linux-android.cpp for details.

  thread_state_flavor_t flavor = x86_THREAD_STATE64;
  x86_thread_state64_t state;
  mach_msg_type_number_t count = x86_THREAD_STATE64_COUNT;
# if __DARWIN_UNIX03
#  define REGISTER_FIELD(name) __r ## name
# else
#  define REGISTER_FIELD(name) r ## name
# endif  // __DARWIN_UNIX03

  if (thread_get_state(samplee_thread,
                       flavor,
                       reinterpret_cast<natural_t*>(&state),
                       &count) == KERN_SUCCESS) {
    Registers regs;
    regs.mPC = reinterpret_cast<Address>(state.REGISTER_FIELD(ip));
    regs.mSP = reinterpret_cast<Address>(state.REGISTER_FIELD(sp));
    regs.mFP = reinterpret_cast<Address>(state.REGISTER_FIELD(bp));
    regs.mLR = 0;

    aProcessRegs(regs);
  }

#undef REGISTER_FIELD

  //----------------------------------------------------------------//
  // Resume the target thread.

  thread_resume(samplee_thread);

  // The profiler's critical section ends here.
  //
  // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
}

// END Sampler target specifics
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
// BEGIN SamplerThread target specifics

static void*
ThreadEntry(void* aArg)
{
  auto thread = static_cast<SamplerThread*>(aArg);
  thread->Run();
  return nullptr;
}

SamplerThread::SamplerThread(PSLockRef aLock,
                             uint32_t aActivityGeneration,
                             double aIntervalMilliseconds)
  : Sampler(aLock)
  , mActivityGeneration(aActivityGeneration)
  , mIntervalMicroseconds(
      std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5))))
  , mThread{nullptr}
{
  pthread_attr_t* attr_ptr = nullptr;
  if (pthread_create(&mThread, attr_ptr, ThreadEntry, this) != 0) {
    MOZ_CRASH("pthread_create failed");
  }
}

SamplerThread::~SamplerThread()
{
  pthread_join(mThread, nullptr);
}

void
SamplerThread::SleepMicro(uint32_t aMicroseconds)
{
  usleep(aMicroseconds);
  // FIXME: the OSX 10.12 page for usleep says "The usleep() function is
  // obsolescent.  Use nanosleep(2) instead."  This implementation could be
  // merged with the linux-android version.  Also, this doesn't handle the
  // case where the usleep call is interrupted by a signal.
}

void
SamplerThread::Stop(PSLockRef aLock)
{
  Sampler::Disable(aLock);
}

// END SamplerThread target specifics
////////////////////////////////////////////////////////////////////////

static void
PlatformInit(PSLockRef aLock)
{
}

#if defined(HAVE_NATIVE_UNWIND)
void
Registers::SyncPopulate()
{
  asm (
      // Compute caller's %rsp by adding to %rbp:
      // 8 bytes for previous %rbp, 8 bytes for return address
      "leaq 0x10(%%rbp), %0\n\t"
      // Dereference %rbp to get previous %rbp
      "movq (%%rbp), %1\n\t"
      :
      "=r"(mSP),
      "=r"(mFP)
  );
  mPC = reinterpret_cast<Address>(__builtin_extract_return_addr(
                                    __builtin_return_address(0)));
  mLR = 0;
}
#endif