1// Copyright 2013 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "src/sampler.h"
6
7#if V8_OS_POSIX && !V8_OS_CYGWIN
8
9#define USE_SIGNALS
10
11#include <errno.h>
12#include <pthread.h>
13#include <signal.h>
14#include <sys/time.h>
15
16#if !V8_OS_QNX && !V8_OS_NACL
17#include <sys/syscall.h>  // NOLINT
18#endif
19
20#if V8_OS_MACOSX
21#include <mach/mach.h>
22// OpenBSD doesn't have <ucontext.h>. ucontext_t lives in <signal.h>
23// and is a typedef for struct sigcontext. There is no uc_mcontext.
24#elif(!V8_OS_ANDROID || defined(__BIONIC_HAVE_UCONTEXT_T)) && \
25    !V8_OS_OPENBSD && !V8_OS_NACL
26#include <ucontext.h>
27#endif
28
29#include <unistd.h>
30
31// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
32// Old versions of the C library <signal.h> didn't define the type.
33#if V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
34    (defined(__arm__) || defined(__aarch64__)) && \
35    !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
36#include <asm/sigcontext.h>  // NOLINT
37#endif
38
39#elif V8_OS_WIN || V8_OS_CYGWIN
40
41#include "src/base/win32-headers.h"
42
43#endif
44
45#include "src/v8.h"
46
47#include "src/base/platform/platform.h"
48#include "src/cpu-profiler-inl.h"
49#include "src/flags.h"
50#include "src/frames-inl.h"
51#include "src/log.h"
52#include "src/simulator.h"
53#include "src/v8threads.h"
54#include "src/vm-state-inl.h"
55
56
57#if V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
58
59// Not all versions of Android's C library provide ucontext_t.
60// Detect this and provide custom but compatible definitions. Note that these
61// follow the GLibc naming convention to access register values from
62// mcontext_t.
63//
64// See http://code.google.com/p/android/issues/detail?id=34784
65
66#if defined(__arm__)
67
68typedef struct sigcontext mcontext_t;
69
70typedef struct ucontext {
71  uint32_t uc_flags;
72  struct ucontext* uc_link;
73  stack_t uc_stack;
74  mcontext_t uc_mcontext;
75  // Other fields are not used by V8, don't define them here.
76} ucontext_t;
77
78#elif defined(__aarch64__)
79
80typedef struct sigcontext mcontext_t;
81
82typedef struct ucontext {
83  uint64_t uc_flags;
84  struct ucontext *uc_link;
85  stack_t uc_stack;
86  mcontext_t uc_mcontext;
87  // Other fields are not used by V8, don't define them here.
88} ucontext_t;
89
90#elif defined(__mips__)
91// MIPS version of sigcontext, for Android bionic.
92typedef struct {
93  uint32_t regmask;
94  uint32_t status;
95  uint64_t pc;
96  uint64_t gregs[32];
97  uint64_t fpregs[32];
98  uint32_t acx;
99  uint32_t fpc_csr;
100  uint32_t fpc_eir;
101  uint32_t used_math;
102  uint32_t dsp;
103  uint64_t mdhi;
104  uint64_t mdlo;
105  uint32_t hi1;
106  uint32_t lo1;
107  uint32_t hi2;
108  uint32_t lo2;
109  uint32_t hi3;
110  uint32_t lo3;
111} mcontext_t;
112
113typedef struct ucontext {
114  uint32_t uc_flags;
115  struct ucontext* uc_link;
116  stack_t uc_stack;
117  mcontext_t uc_mcontext;
118  // Other fields are not used by V8, don't define them here.
119} ucontext_t;
120
121#elif defined(__i386__)
122// x86 version for Android.
123typedef struct {
124  uint32_t gregs[19];
125  void* fpregs;
126  uint32_t oldmask;
127  uint32_t cr2;
128} mcontext_t;
129
130typedef uint32_t kernel_sigset_t[2];  // x86 kernel uses 64-bit signal masks
131typedef struct ucontext {
132  uint32_t uc_flags;
133  struct ucontext* uc_link;
134  stack_t uc_stack;
135  mcontext_t uc_mcontext;
136  // Other fields are not used by V8, don't define them here.
137} ucontext_t;
138enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
139
140#elif defined(__x86_64__)
141// x64 version for Android.
142typedef struct {
143  uint64_t gregs[23];
144  void* fpregs;
145  uint64_t __reserved1[8];
146} mcontext_t;
147
148typedef struct ucontext {
149  uint64_t uc_flags;
150  struct ucontext *uc_link;
151  stack_t uc_stack;
152  mcontext_t uc_mcontext;
153  // Other fields are not used by V8, don't define them here.
154} ucontext_t;
155enum { REG_RBP = 10, REG_RSP = 15, REG_RIP = 16 };
156#endif
157
158#endif  // V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
159
160
161namespace v8 {
162namespace internal {
163
164namespace {
165
166class PlatformDataCommon : public Malloced {
167 public:
168  PlatformDataCommon() : profiled_thread_id_(ThreadId::Current()) {}
169  ThreadId profiled_thread_id() { return profiled_thread_id_; }
170
171 protected:
172  ~PlatformDataCommon() {}
173
174 private:
175  ThreadId profiled_thread_id_;
176};
177
178}  // namespace
179
180#if defined(USE_SIGNALS)
181
182class Sampler::PlatformData : public PlatformDataCommon {
183 public:
184  PlatformData() : vm_tid_(pthread_self()) {}
185  pthread_t vm_tid() const { return vm_tid_; }
186
187 private:
188  pthread_t vm_tid_;
189};
190
191#elif V8_OS_WIN || V8_OS_CYGWIN
192
193// ----------------------------------------------------------------------------
194// Win32 profiler support. On Cygwin we use the same sampler implementation as
195// on Win32.
196
197class Sampler::PlatformData : public PlatformDataCommon {
198 public:
199  // Get a handle to the calling thread. This is the thread that we are
200  // going to profile. We need to make a copy of the handle because we are
201  // going to use it in the sampler thread. Using GetThreadHandle() will
202  // not work in this case. We're using OpenThread because DuplicateHandle
203  // for some reason doesn't work in Chrome's sandbox.
204  PlatformData()
205      : profiled_thread_(OpenThread(THREAD_GET_CONTEXT |
206                                    THREAD_SUSPEND_RESUME |
207                                    THREAD_QUERY_INFORMATION,
208                                    false,
209                                    GetCurrentThreadId())) {}
210
211  ~PlatformData() {
212    if (profiled_thread_ != NULL) {
213      CloseHandle(profiled_thread_);
214      profiled_thread_ = NULL;
215    }
216  }
217
218  HANDLE profiled_thread() { return profiled_thread_; }
219
220 private:
221  HANDLE profiled_thread_;
222};
223#endif
224
225
226#if defined(USE_SIMULATOR)
227class SimulatorHelper {
228 public:
229  inline bool Init(Sampler* sampler, Isolate* isolate) {
230    simulator_ = isolate->thread_local_top()->simulator_;
231    // Check if there is active simulator.
232    return simulator_ != NULL;
233  }
234
235  inline void FillRegisters(RegisterState* state) {
236#if V8_TARGET_ARCH_ARM
237    state->pc = reinterpret_cast<Address>(simulator_->get_pc());
238    state->sp = reinterpret_cast<Address>(simulator_->get_register(
239        Simulator::sp));
240    state->fp = reinterpret_cast<Address>(simulator_->get_register(
241        Simulator::r11));
242#elif V8_TARGET_ARCH_ARM64
243    if (simulator_->sp() == 0 || simulator_->fp() == 0) {
244      // It possible that the simulator is interrupted while it is updating
245      // the sp or fp register. ARM64 simulator does this in two steps:
246      // first setting it to zero and then setting it to the new value.
247      // Bailout if sp/fp doesn't contain the new value.
248      return;
249    }
250    state->pc = reinterpret_cast<Address>(simulator_->pc());
251    state->sp = reinterpret_cast<Address>(simulator_->sp());
252    state->fp = reinterpret_cast<Address>(simulator_->fp());
253#elif V8_TARGET_ARCH_MIPS
254    state->pc = reinterpret_cast<Address>(simulator_->get_pc());
255    state->sp = reinterpret_cast<Address>(simulator_->get_register(
256        Simulator::sp));
257    state->fp = reinterpret_cast<Address>(simulator_->get_register(
258        Simulator::fp));
259#elif V8_TARGET_ARCH_MIPS64
260    state->pc = reinterpret_cast<Address>(simulator_->get_pc());
261    state->sp = reinterpret_cast<Address>(simulator_->get_register(
262        Simulator::sp));
263    state->fp = reinterpret_cast<Address>(simulator_->get_register(
264        Simulator::fp));
265#endif
266  }
267
268 private:
269  Simulator* simulator_;
270};
271#endif  // USE_SIMULATOR
272
273
274#if defined(USE_SIGNALS)
275
276class SignalHandler : public AllStatic {
277 public:
278  static void SetUp() { if (!mutex_) mutex_ = new base::Mutex(); }
279  static void TearDown() { delete mutex_; mutex_ = NULL; }
280
281  static void IncreaseSamplerCount() {
282    base::LockGuard<base::Mutex> lock_guard(mutex_);
283    if (++client_count_ == 1) Install();
284  }
285
286  static void DecreaseSamplerCount() {
287    base::LockGuard<base::Mutex> lock_guard(mutex_);
288    if (--client_count_ == 0) Restore();
289  }
290
291  static bool Installed() {
292    return signal_handler_installed_;
293  }
294
295 private:
296  static void Install() {
297#if !V8_OS_NACL
298    struct sigaction sa;
299    sa.sa_sigaction = &HandleProfilerSignal;
300    sigemptyset(&sa.sa_mask);
301#if V8_OS_QNX
302    sa.sa_flags = SA_SIGINFO;
303#else
304    sa.sa_flags = SA_RESTART | SA_SIGINFO;
305#endif
306    signal_handler_installed_ =
307        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
308#endif
309  }
310
311  static void Restore() {
312#if !V8_OS_NACL
313    if (signal_handler_installed_) {
314      sigaction(SIGPROF, &old_signal_handler_, 0);
315      signal_handler_installed_ = false;
316    }
317#endif
318  }
319
320#if !V8_OS_NACL
321  static void HandleProfilerSignal(int signal, siginfo_t* info, void* context);
322#endif
323  // Protects the process wide state below.
324  static base::Mutex* mutex_;
325  static int client_count_;
326  static bool signal_handler_installed_;
327  static struct sigaction old_signal_handler_;
328};
329
330
331base::Mutex* SignalHandler::mutex_ = NULL;
332int SignalHandler::client_count_ = 0;
333struct sigaction SignalHandler::old_signal_handler_;
334bool SignalHandler::signal_handler_installed_ = false;
335
336
337// As Native Client does not support signal handling, profiling is disabled.
338#if !V8_OS_NACL
339void SignalHandler::HandleProfilerSignal(int signal, siginfo_t* info,
340                                         void* context) {
341  USE(info);
342  if (signal != SIGPROF) return;
343  Isolate* isolate = Isolate::UnsafeCurrent();
344  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
345    // We require a fully initialized and entered isolate.
346    return;
347  }
348  if (v8::Locker::IsActive() &&
349      !isolate->thread_manager()->IsLockedByCurrentThread()) {
350    return;
351  }
352
353  Sampler* sampler = isolate->logger()->sampler();
354  if (sampler == NULL) return;
355
356  RegisterState state;
357
358#if defined(USE_SIMULATOR)
359  SimulatorHelper helper;
360  if (!helper.Init(sampler, isolate)) return;
361  helper.FillRegisters(&state);
362  // It possible that the simulator is interrupted while it is updating
363  // the sp or fp register. ARM64 simulator does this in two steps:
364  // first setting it to zero and then setting it to the new value.
365  // Bailout if sp/fp doesn't contain the new value.
366  if (state.sp == 0 || state.fp == 0) return;
367#else
368  // Extracting the sample from the context is extremely machine dependent.
369  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
370#if !V8_OS_OPENBSD
371  mcontext_t& mcontext = ucontext->uc_mcontext;
372#endif
373#if V8_OS_LINUX
374#if V8_HOST_ARCH_IA32
375  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
376  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
377  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
378#elif V8_HOST_ARCH_X64
379  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
380  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
381  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
382#elif V8_HOST_ARCH_ARM
383#if defined(__GLIBC__) && !defined(__UCLIBC__) && \
384    (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
385  // Old GLibc ARM versions used a gregs[] array to access the register
386  // values from mcontext_t.
387  state.pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
388  state.sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
389  state.fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
390#else
391  state.pc = reinterpret_cast<Address>(mcontext.arm_pc);
392  state.sp = reinterpret_cast<Address>(mcontext.arm_sp);
393  state.fp = reinterpret_cast<Address>(mcontext.arm_fp);
394#endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
395        // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
396#elif V8_HOST_ARCH_ARM64
397  state.pc = reinterpret_cast<Address>(mcontext.pc);
398  state.sp = reinterpret_cast<Address>(mcontext.sp);
399  // FP is an alias for x29.
400  state.fp = reinterpret_cast<Address>(mcontext.regs[29]);
401#elif V8_HOST_ARCH_MIPS
402  state.pc = reinterpret_cast<Address>(mcontext.pc);
403  state.sp = reinterpret_cast<Address>(mcontext.gregs[29]);
404  state.fp = reinterpret_cast<Address>(mcontext.gregs[30]);
405#elif V8_HOST_ARCH_MIPS64
406  state.pc = reinterpret_cast<Address>(mcontext.pc);
407  state.sp = reinterpret_cast<Address>(mcontext.gregs[29]);
408  state.fp = reinterpret_cast<Address>(mcontext.gregs[30]);
409#endif  // V8_HOST_ARCH_*
410#elif V8_OS_MACOSX
411#if V8_HOST_ARCH_X64
412#if __DARWIN_UNIX03
413  state.pc = reinterpret_cast<Address>(mcontext->__ss.__rip);
414  state.sp = reinterpret_cast<Address>(mcontext->__ss.__rsp);
415  state.fp = reinterpret_cast<Address>(mcontext->__ss.__rbp);
416#else  // !__DARWIN_UNIX03
417  state.pc = reinterpret_cast<Address>(mcontext->ss.rip);
418  state.sp = reinterpret_cast<Address>(mcontext->ss.rsp);
419  state.fp = reinterpret_cast<Address>(mcontext->ss.rbp);
420#endif  // __DARWIN_UNIX03
421#elif V8_HOST_ARCH_IA32
422#if __DARWIN_UNIX03
423  state.pc = reinterpret_cast<Address>(mcontext->__ss.__eip);
424  state.sp = reinterpret_cast<Address>(mcontext->__ss.__esp);
425  state.fp = reinterpret_cast<Address>(mcontext->__ss.__ebp);
426#else  // !__DARWIN_UNIX03
427  state.pc = reinterpret_cast<Address>(mcontext->ss.eip);
428  state.sp = reinterpret_cast<Address>(mcontext->ss.esp);
429  state.fp = reinterpret_cast<Address>(mcontext->ss.ebp);
430#endif  // __DARWIN_UNIX03
431#endif  // V8_HOST_ARCH_IA32
432#elif V8_OS_FREEBSD
433#if V8_HOST_ARCH_IA32
434  state.pc = reinterpret_cast<Address>(mcontext.mc_eip);
435  state.sp = reinterpret_cast<Address>(mcontext.mc_esp);
436  state.fp = reinterpret_cast<Address>(mcontext.mc_ebp);
437#elif V8_HOST_ARCH_X64
438  state.pc = reinterpret_cast<Address>(mcontext.mc_rip);
439  state.sp = reinterpret_cast<Address>(mcontext.mc_rsp);
440  state.fp = reinterpret_cast<Address>(mcontext.mc_rbp);
441#elif V8_HOST_ARCH_ARM
442  state.pc = reinterpret_cast<Address>(mcontext.mc_r15);
443  state.sp = reinterpret_cast<Address>(mcontext.mc_r13);
444  state.fp = reinterpret_cast<Address>(mcontext.mc_r11);
445#endif  // V8_HOST_ARCH_*
446#elif V8_OS_NETBSD
447#if V8_HOST_ARCH_IA32
448  state.pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_EIP]);
449  state.sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_ESP]);
450  state.fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_EBP]);
451#elif V8_HOST_ARCH_X64
452  state.pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_RIP]);
453  state.sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RSP]);
454  state.fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RBP]);
455#endif  // V8_HOST_ARCH_*
456#elif V8_OS_OPENBSD
457#if V8_HOST_ARCH_IA32
458  state.pc = reinterpret_cast<Address>(ucontext->sc_eip);
459  state.sp = reinterpret_cast<Address>(ucontext->sc_esp);
460  state.fp = reinterpret_cast<Address>(ucontext->sc_ebp);
461#elif V8_HOST_ARCH_X64
462  state.pc = reinterpret_cast<Address>(ucontext->sc_rip);
463  state.sp = reinterpret_cast<Address>(ucontext->sc_rsp);
464  state.fp = reinterpret_cast<Address>(ucontext->sc_rbp);
465#endif  // V8_HOST_ARCH_*
466#elif V8_OS_SOLARIS
467  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_PC]);
468  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_SP]);
469  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_FP]);
470#elif V8_OS_QNX
471#if V8_HOST_ARCH_IA32
472  state.pc = reinterpret_cast<Address>(mcontext.cpu.eip);
473  state.sp = reinterpret_cast<Address>(mcontext.cpu.esp);
474  state.fp = reinterpret_cast<Address>(mcontext.cpu.ebp);
475#elif V8_HOST_ARCH_ARM
476  state.pc = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_PC]);
477  state.sp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_SP]);
478  state.fp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_FP]);
479#endif  // V8_HOST_ARCH_*
480#endif  // V8_OS_QNX
481#endif  // USE_SIMULATOR
482  sampler->SampleStack(state);
483}
484#endif  // V8_OS_NACL
485
486#endif
487
488
489class SamplerThread : public base::Thread {
490 public:
491  static const int kSamplerThreadStackSize = 64 * KB;
492
493  explicit SamplerThread(int interval)
494      : Thread(base::Thread::Options("SamplerThread", kSamplerThreadStackSize)),
495        interval_(interval) {}
496
497  static void SetUp() { if (!mutex_) mutex_ = new base::Mutex(); }
498  static void TearDown() { delete mutex_; mutex_ = NULL; }
499
500  static void AddActiveSampler(Sampler* sampler) {
501    bool need_to_start = false;
502    base::LockGuard<base::Mutex> lock_guard(mutex_);
503    if (instance_ == NULL) {
504      // Start a thread that will send SIGPROF signal to VM threads,
505      // when CPU profiling will be enabled.
506      instance_ = new SamplerThread(sampler->interval());
507      need_to_start = true;
508    }
509
510    DCHECK(sampler->IsActive());
511    DCHECK(!instance_->active_samplers_.Contains(sampler));
512    DCHECK(instance_->interval_ == sampler->interval());
513    instance_->active_samplers_.Add(sampler);
514
515    if (need_to_start) instance_->StartSynchronously();
516  }
517
518  static void RemoveActiveSampler(Sampler* sampler) {
519    SamplerThread* instance_to_remove = NULL;
520    {
521      base::LockGuard<base::Mutex> lock_guard(mutex_);
522
523      DCHECK(sampler->IsActive());
524      bool removed = instance_->active_samplers_.RemoveElement(sampler);
525      DCHECK(removed);
526      USE(removed);
527
528      // We cannot delete the instance immediately as we need to Join() the
529      // thread but we are holding mutex_ and the thread may try to acquire it.
530      if (instance_->active_samplers_.is_empty()) {
531        instance_to_remove = instance_;
532        instance_ = NULL;
533      }
534    }
535
536    if (!instance_to_remove) return;
537    instance_to_remove->Join();
538    delete instance_to_remove;
539  }
540
541  // Implement Thread::Run().
542  virtual void Run() {
543    while (true) {
544      {
545        base::LockGuard<base::Mutex> lock_guard(mutex_);
546        if (active_samplers_.is_empty()) break;
547        // When CPU profiling is enabled both JavaScript and C++ code is
548        // profiled. We must not suspend.
549        for (int i = 0; i < active_samplers_.length(); ++i) {
550          Sampler* sampler = active_samplers_.at(i);
551          if (!sampler->isolate()->IsInitialized()) continue;
552          if (!sampler->IsProfiling()) continue;
553          sampler->DoSample();
554        }
555      }
556      base::OS::Sleep(interval_);
557    }
558  }
559
560 private:
561  // Protects the process wide state below.
562  static base::Mutex* mutex_;
563  static SamplerThread* instance_;
564
565  const int interval_;
566  List<Sampler*> active_samplers_;
567
568  DISALLOW_COPY_AND_ASSIGN(SamplerThread);
569};
570
571
572base::Mutex* SamplerThread::mutex_ = NULL;
573SamplerThread* SamplerThread::instance_ = NULL;
574
575
576//
577// StackTracer implementation
578//
579DISABLE_ASAN void TickSample::Init(Isolate* isolate,
580                                   const RegisterState& regs) {
581  DCHECK(isolate->IsInitialized());
582  timestamp = base::TimeTicks::HighResolutionNow();
583  pc = regs.pc;
584  state = isolate->current_vm_state();
585
586  // Avoid collecting traces while doing GC.
587  if (state == GC) return;
588
589  Address js_entry_sp = isolate->js_entry_sp();
590  if (js_entry_sp == 0) {
591    // Not executing JS now.
592    return;
593  }
594
595  ExternalCallbackScope* scope = isolate->external_callback_scope();
596  Address handler = Isolate::handler(isolate->thread_local_top());
597  // If there is a handler on top of the external callback scope then
598  // we have already entrered JavaScript again and the external callback
599  // is not the top function.
600  if (scope && scope->scope_address() < handler) {
601    external_callback = scope->callback();
602    has_external_callback = true;
603  } else {
604    // Sample potential return address value for frameless invocation of
605    // stubs (we'll figure out later, if this value makes sense).
606    tos = Memory::Address_at(regs.sp);
607    has_external_callback = false;
608  }
609
610  SafeStackFrameIterator it(isolate, regs.fp, regs.sp, js_entry_sp);
611  top_frame_type = it.top_frame_type();
612  unsigned i = 0;
613  while (!it.done() && i < TickSample::kMaxFramesCount) {
614    stack[i++] = it.frame()->pc();
615    it.Advance();
616  }
617  frames_count = i;
618}
619
620
621void Sampler::SetUp() {
622#if defined(USE_SIGNALS)
623  SignalHandler::SetUp();
624#endif
625  SamplerThread::SetUp();
626}
627
628
629void Sampler::TearDown() {
630  SamplerThread::TearDown();
631#if defined(USE_SIGNALS)
632  SignalHandler::TearDown();
633#endif
634}
635
636
637Sampler::Sampler(Isolate* isolate, int interval)
638    : isolate_(isolate),
639      interval_(interval),
640      profiling_(false),
641      has_processing_thread_(false),
642      active_(false),
643      is_counting_samples_(false),
644      js_and_external_sample_count_(0) {
645  data_ = new PlatformData;
646}
647
648
649Sampler::~Sampler() {
650  DCHECK(!IsActive());
651  delete data_;
652}
653
654
655void Sampler::Start() {
656  DCHECK(!IsActive());
657  SetActive(true);
658  SamplerThread::AddActiveSampler(this);
659}
660
661
662void Sampler::Stop() {
663  DCHECK(IsActive());
664  SamplerThread::RemoveActiveSampler(this);
665  SetActive(false);
666}
667
668
669void Sampler::IncreaseProfilingDepth() {
670  base::NoBarrier_AtomicIncrement(&profiling_, 1);
671#if defined(USE_SIGNALS)
672  SignalHandler::IncreaseSamplerCount();
673#endif
674}
675
676
677void Sampler::DecreaseProfilingDepth() {
678#if defined(USE_SIGNALS)
679  SignalHandler::DecreaseSamplerCount();
680#endif
681  base::NoBarrier_AtomicIncrement(&profiling_, -1);
682}
683
684
685void Sampler::SampleStack(const RegisterState& state) {
686  TickSample* sample = isolate_->cpu_profiler()->StartTickSample();
687  TickSample sample_obj;
688  if (sample == NULL) sample = &sample_obj;
689  sample->Init(isolate_, state);
690  if (is_counting_samples_) {
691    if (sample->state == JS || sample->state == EXTERNAL) {
692      ++js_and_external_sample_count_;
693    }
694  }
695  Tick(sample);
696  if (sample != &sample_obj) {
697    isolate_->cpu_profiler()->FinishTickSample();
698  }
699}
700
701
702#if defined(USE_SIGNALS)
703
704void Sampler::DoSample() {
705  if (!SignalHandler::Installed()) return;
706  pthread_kill(platform_data()->vm_tid(), SIGPROF);
707}
708
709#elif V8_OS_WIN || V8_OS_CYGWIN
710
711void Sampler::DoSample() {
712  HANDLE profiled_thread = platform_data()->profiled_thread();
713  if (profiled_thread == NULL) return;
714
715#if defined(USE_SIMULATOR)
716  SimulatorHelper helper;
717  if (!helper.Init(this, isolate())) return;
718#endif
719
720  const DWORD kSuspendFailed = static_cast<DWORD>(-1);
721  if (SuspendThread(profiled_thread) == kSuspendFailed) return;
722
723  // Context used for sampling the register state of the profiled thread.
724  CONTEXT context;
725  memset(&context, 0, sizeof(context));
726  context.ContextFlags = CONTEXT_FULL;
727  if (GetThreadContext(profiled_thread, &context) != 0) {
728    RegisterState state;
729#if defined(USE_SIMULATOR)
730    helper.FillRegisters(&state);
731#else
732#if V8_HOST_ARCH_X64
733    state.pc = reinterpret_cast<Address>(context.Rip);
734    state.sp = reinterpret_cast<Address>(context.Rsp);
735    state.fp = reinterpret_cast<Address>(context.Rbp);
736#else
737    state.pc = reinterpret_cast<Address>(context.Eip);
738    state.sp = reinterpret_cast<Address>(context.Esp);
739    state.fp = reinterpret_cast<Address>(context.Ebp);
740#endif
741#endif  // USE_SIMULATOR
742    SampleStack(state);
743  }
744  ResumeThread(profiled_thread);
745}
746
747#endif  // USE_SIGNALS
748
749
750} }  // namespace v8::internal
751