From: yurys@chromium.org <yurys@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Mon, 15 Apr 2013 13:57:41 +0000 (+0000)
Subject: Move *BSD and Solaris Sampler implementation into sampler.cc
X-Git-Tag: upstream/4.7.83~14582
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1596afa7f9131d67b79908d09ead8354864a0e82;p=platform%2Fupstream%2Fv8.git

Move *BSD and Solaris Sampler implementation into sampler.cc

This is a first step to having profiler sampler implementation in one file with platform capabilities guarded with #ifdef. Otherwise we have very similar implementations scattered over platform-*.cc files which makes it hard to see differences and make changes.

The next steps will be to merge win32, Mac OS X and Cygwin implementations into sampler.cc They suspend profiled thread instead of sending a signal but apart from that the logic is pretty much the same. Then I'm going to move sampler-related code from log.* into sampler.*

BUG=None

Review URL: https://codereview.chromium.org/13852005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14265 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---

diff --git a/src/log.cc b/src/log.cc
index 3e1ff1e..3984d01 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -170,11 +170,6 @@ class Ticker: public Sampler {
     if (IsActive()) Stop();
   }
 
- protected:
-  virtual void DoSampleStack(TickSample* sample) {
-    StackTracer::Trace(isolate(), sample);
-  }
-
  private:
   Profiler* profiler_;
 };
diff --git a/src/platform-freebsd.cc b/src/platform-freebsd.cc
index e9db66d..735f078 100644
--- a/src/platform-freebsd.cc
+++ b/src/platform-freebsd.cc
@@ -56,7 +56,6 @@
 
 #include "platform-posix.h"
 #include "platform.h"
-#include "simulator.h"
 #include "vm-state-inl.h"
 
 
@@ -683,200 +682,6 @@ Semaphore* OS::CreateSemaphore(int count) {
 }
 
 
-static pthread_t GetThreadID() {
-  pthread_t thread_id = pthread_self();
-  return thread_id;
-}
-
-
-class Sampler::PlatformData : public Malloced {
- public:
-  PlatformData()
-      : vm_tid_(GetThreadID()),
-        profiled_thread_id_(ThreadId::Current()) {}
-
-  pthread_t vm_tid() const { return vm_tid_; }
-  ThreadId profiled_thread_id() { return profiled_thread_id_; }
-
- private:
-  pthread_t vm_tid_;
-  ThreadId profiled_thread_id_;
-};
-
-
-static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
-  USE(info);
-  if (signal != SIGPROF) return;
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
-    // We require a fully initialized and entered isolate.
-    return;
-  }
-  if (v8::Locker::IsActive() &&
-      !isolate->thread_manager()->IsLockedByCurrentThread()) {
-    return;
-  }
-
-  Sampler* sampler = isolate->logger()->sampler();
-  if (sampler == NULL || !sampler->IsActive()) return;
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
-  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
-  Isolate::PerIsolateThreadData* per_thread_data = isolate->
-      FindPerThreadDataForThread(thread_id);
-  if (!per_thread_data) return;
-  Simulator* sim = per_thread_data->simulator();
-  // Check if there is active simulator before allocating TickSample.
-  if (!sim) return;
-#endif
-#endif  // USE_SIMULATOR
-
-  TickSample sample_obj;
-  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
-  if (sample == NULL) sample = &sample_obj;
-
-  // Extracting the sample from the context is extremely machine dependent.
-  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
-  mcontext_t& mcontext = ucontext->uc_mcontext;
-  sample->state = isolate->current_vm_state();
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
-#elif V8_TARGET_ARCH_MIPS
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
-#endif
-#else
-#if V8_HOST_ARCH_IA32
-  sample->pc = reinterpret_cast<Address>(mcontext.mc_eip);
-  sample->sp = reinterpret_cast<Address>(mcontext.mc_esp);
-  sample->fp = reinterpret_cast<Address>(mcontext.mc_ebp);
-#elif V8_HOST_ARCH_X64
-  sample->pc = reinterpret_cast<Address>(mcontext.mc_rip);
-  sample->sp = reinterpret_cast<Address>(mcontext.mc_rsp);
-  sample->fp = reinterpret_cast<Address>(mcontext.mc_rbp);
-#elif V8_HOST_ARCH_ARM
-  sample->pc = reinterpret_cast<Address>(mcontext.mc_r15);
-  sample->sp = reinterpret_cast<Address>(mcontext.mc_r13);
-  sample->fp = reinterpret_cast<Address>(mcontext.mc_r11);
-#endif  // V8_HOST_ARCH_*
-#endif  // USE_SIMULATOR
-  sampler->SampleStack(sample);
-  sampler->Tick(sample);
-}
-
-
-class SignalSender : public Thread {
- public:
-  static const int kSignalSenderStackSize = 64 * KB;
-
-  explicit SignalSender(int interval)
-      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
-        interval_(interval) {}
-
-  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
-  static void TearDown() { delete mutex_; }
-
-  static void AddActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::AddActiveSampler(sampler);
-    if (instance_ == NULL) {
-      // Install a signal handler.
-      struct sigaction sa;
-      sa.sa_sigaction = ProfilerSignalHandler;
-      sigemptyset(&sa.sa_mask);
-      sa.sa_flags = SA_RESTART | SA_SIGINFO;
-      signal_handler_installed_ =
-          (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
-
-      // Start a thread that sends SIGPROF signal to VM threads.
-      instance_ = new SignalSender(sampler->interval());
-      instance_->StartSynchronously();
-    } else {
-      ASSERT(instance_->interval_ == sampler->interval());
-    }
-  }
-
-  static void RemoveActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::RemoveActiveSampler(sampler);
-    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
-      instance_->Join();
-      delete instance_;
-      instance_ = NULL;
-
-      // Restore the old signal handler.
-      if (signal_handler_installed_) {
-        sigaction(SIGPROF, &old_signal_handler_, 0);
-        signal_handler_installed_ = false;
-      }
-    }
-  }
-
-  // Implement Thread::Run().
-  virtual void Run() {
-    SamplerRegistry::State state;
-    while ((state = SamplerRegistry::GetState()) !=
-           SamplerRegistry::HAS_NO_SAMPLERS) {
-      // When CPU profiling is enabled both JavaScript and C++ code is
-      // profiled. We must not suspend.
-      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
-        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
-      }
-      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
-    }
-  }
-
-  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
-    if (!sampler->IsProfiling()) return;
-    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
-    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
-  }
-
-  void SendProfilingSignal(pthread_t tid) {
-    if (!signal_handler_installed_) return;
-    pthread_kill(tid, SIGPROF);
-  }
-
-  void Sleep() {
-    // Convert ms to us and subtract 100 us to compensate delays
-    // occuring during signal delivery.
-    useconds_t interval = interval_ * 1000 - 100;
-    int result = usleep(interval);
-#ifdef DEBUG
-    if (result != 0 && errno != EINTR) {
-      fprintf(stderr,
-              "SignalSender usleep error; interval = %u, errno = %d\n",
-              interval,
-              errno);
-      ASSERT(result == 0 || errno == EINTR);
-    }
-#endif
-    USE(result);
-  }
-
-  const int interval_;
-
-  // Protects the process wide state below.
-  static Mutex* mutex_;
-  static SignalSender* instance_;
-  static bool signal_handler_installed_;
-  static struct sigaction old_signal_handler_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SignalSender);
-};
-
-Mutex* SignalSender::mutex_ = NULL;
-SignalSender* SignalSender::instance_ = NULL;
-struct sigaction SignalSender::old_signal_handler_;
-bool SignalSender::signal_handler_installed_ = false;
-
-
 void OS::SetUp() {
   // Seed the random number generator.
   // Convert the current time to a 64-bit integer first, before converting it
@@ -886,44 +691,12 @@ void OS::SetUp() {
   uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
   srandom(static_cast<unsigned int>(seed));
   limit_mutex = CreateMutex();
-  SignalSender::SetUp();
 }
 
 
 void OS::TearDown() {
-  SignalSender::TearDown();
   delete limit_mutex;
 }
 
 
-Sampler::Sampler(Isolate* isolate, int interval)
-    : isolate_(isolate),
-      interval_(interval),
-      profiling_(false),
-      active_(false),
-      samples_taken_(0) {
-  data_ = new PlatformData;
-}
-
-
-Sampler::~Sampler() {
-  ASSERT(!IsActive());
-  delete data_;
-}
-
-
-void Sampler::Start() {
-  ASSERT(!IsActive());
-  SetActive(true);
-  SignalSender::AddActiveSampler(this);
-}
-
-
-void Sampler::Stop() {
-  ASSERT(IsActive());
-  SignalSender::RemoveActiveSampler(this);
-  SetActive(false);
-}
-
-
 } }  // namespace v8::internal
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index 20d1be9..4ac69ec 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -68,7 +68,6 @@
 
 #include "platform-posix.h"
 #include "platform.h"
-#include "simulator.h"
 #include "v8threads.h"
 #include "vm-state-inl.h"
 
@@ -992,320 +991,6 @@ Semaphore* OS::CreateSemaphore(int count) {
 }
 
 
-#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T)
-
-// Not all versions of Android's C library provide ucontext_t.
-// Detect this and provide custom but compatible definitions. Note that these
-// follow the GLibc naming convention to access register values from
-// mcontext_t.
-//
-// See http://code.google.com/p/android/issues/detail?id=34784
-
-#if defined(__arm__)
-
-typedef struct sigcontext mcontext_t;
-
-typedef struct ucontext {
-  uint32_t uc_flags;
-  struct ucontext* uc_link;
-  stack_t uc_stack;
-  mcontext_t uc_mcontext;
-  // Other fields are not used by V8, don't define them here.
-} ucontext_t;
-
-#elif defined(__mips__)
-// MIPS version of sigcontext, for Android bionic.
-typedef struct {
-  uint32_t regmask;
-  uint32_t status;
-  uint64_t pc;
-  uint64_t gregs[32];
-  uint64_t fpregs[32];
-  uint32_t acx;
-  uint32_t fpc_csr;
-  uint32_t fpc_eir;
-  uint32_t used_math;
-  uint32_t dsp;
-  uint64_t mdhi;
-  uint64_t mdlo;
-  uint32_t hi1;
-  uint32_t lo1;
-  uint32_t hi2;
-  uint32_t lo2;
-  uint32_t hi3;
-  uint32_t lo3;
-} mcontext_t;
-
-typedef struct ucontext {
-  uint32_t uc_flags;
-  struct ucontext* uc_link;
-  stack_t uc_stack;
-  mcontext_t uc_mcontext;
-  // Other fields are not used by V8, don't define them here.
-} ucontext_t;
-
-#elif defined(__i386__)
-// x86 version for Android.
-typedef struct {
-  uint32_t gregs[19];
-  void* fpregs;
-  uint32_t oldmask;
-  uint32_t cr2;
-} mcontext_t;
-
-typedef uint32_t kernel_sigset_t[2];  // x86 kernel uses 64-bit signal masks
-typedef struct ucontext {
-  uint32_t uc_flags;
-  struct ucontext* uc_link;
-  stack_t uc_stack;
-  mcontext_t uc_mcontext;
-  // Other fields are not used by V8, don't define them here.
-} ucontext_t;
-enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
-#endif
-
-#endif  // __ANDROID__ && !defined(__BIONIC_HAVE_UCONTEXT_T)
-
-static int GetThreadID() {
-#if defined(__ANDROID__)
-  // Android's C library provides gettid(2).
-  return gettid();
-#else
-  // Glibc doesn't provide a wrapper for gettid(2).
-  return syscall(SYS_gettid);
-#endif
-}
-
-
-class Sampler::PlatformData : public Malloced {
- public:
-  PlatformData()
-      : vm_tid_(GetThreadID()),
-        profiled_thread_id_(ThreadId::Current()) {}
-
-  pthread_t vm_tid() const { return vm_tid_; }
-  ThreadId profiled_thread_id() { return profiled_thread_id_; }
-
- private:
-  pthread_t vm_tid_;
-  ThreadId profiled_thread_id_;
-};
-
-
-static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
-#if defined(__native_client__)
-  // As Native Client does not support signal handling, profiling
-  // is disabled.
-  return;
-#else
-  USE(info);
-  if (signal != SIGPROF) return;
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
-    // We require a fully initialized and entered isolate.
-    return;
-  }
-  if (v8::Locker::IsActive() &&
-      !isolate->thread_manager()->IsLockedByCurrentThread()) {
-    return;
-  }
-
-  Sampler* sampler = isolate->logger()->sampler();
-  if (sampler == NULL || !sampler->IsActive()) return;
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
-  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
-  Isolate::PerIsolateThreadData* per_thread_data = isolate->
-      FindPerThreadDataForThread(thread_id);
-  if (!per_thread_data) return;
-  Simulator* sim = per_thread_data->simulator();
-  // Check if there is active simulator before allocating TickSample.
-  if (!sim) return;
-#endif
-#endif  // USE_SIMULATOR
-
-  TickSample sample_obj;
-  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
-  if (sample == NULL) sample = &sample_obj;
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
-#elif V8_TARGET_ARCH_MIPS
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
-#endif
-#else
-  // Extracting the sample from the context is extremely machine dependent.
-  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
-  mcontext_t& mcontext = ucontext->uc_mcontext;
-  sample->state = isolate->current_vm_state();
-#if V8_HOST_ARCH_IA32
-  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
-#elif V8_HOST_ARCH_X64
-  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
-#elif V8_HOST_ARCH_ARM
-#if defined(__GLIBC__) && !defined(__UCLIBC__) && \
-    (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
-  // Old GLibc ARM versions used a gregs[] array to access the register
-  // values from mcontext_t.
-  sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
-#else
-  sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
-  sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
-  sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
-#endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
-        // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
-#elif V8_HOST_ARCH_MIPS
-  sample->pc = reinterpret_cast<Address>(mcontext.pc);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[29]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[30]);
-#endif  // V8_HOST_ARCH_*
-#endif  // USE_SIMULATOR
-  sampler->SampleStack(sample);
-  sampler->Tick(sample);
-#endif  // __native_client__
-}
-
-
-class SignalSender : public Thread {
- public:
-  static const int kSignalSenderStackSize = 64 * KB;
-
-  explicit SignalSender(int interval)
-      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
-        vm_tgid_(getpid()),
-        interval_(interval) {}
-
-  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
-  static void TearDown() { delete mutex_; }
-
-  static void InstallSignalHandler() {
-    struct sigaction sa;
-    sa.sa_sigaction = ProfilerSignalHandler;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = SA_RESTART | SA_SIGINFO;
-    signal_handler_installed_ =
-        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
-  }
-
-  static void RestoreSignalHandler() {
-    if (signal_handler_installed_) {
-      sigaction(SIGPROF, &old_signal_handler_, 0);
-      signal_handler_installed_ = false;
-    }
-  }
-
-  static void AddActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::AddActiveSampler(sampler);
-    if (instance_ == NULL) {
-      // Start a thread that will send SIGPROF signal to VM threads,
-      // when CPU profiling will be enabled.
-      instance_ = new SignalSender(sampler->interval());
-      instance_->StartSynchronously();
-    } else {
-      ASSERT(instance_->interval_ == sampler->interval());
-    }
-  }
-
-  static void RemoveActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::RemoveActiveSampler(sampler);
-    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
-      instance_->Join();
-      delete instance_;
-      instance_ = NULL;
-      RestoreSignalHandler();
-    }
-  }
-
-  // Implement Thread::Run().
-  virtual void Run() {
-    SamplerRegistry::State state;
-    while ((state = SamplerRegistry::GetState()) !=
-           SamplerRegistry::HAS_NO_SAMPLERS) {
-      // When CPU profiling is enabled both JavaScript and C++ code is
-      // profiled. We must not suspend.
-      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
-        if (!signal_handler_installed_) InstallSignalHandler();
-        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
-      } else {
-        if (signal_handler_installed_) RestoreSignalHandler();
-      }
-      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
-    }
-  }
-
-  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
-    if (!sampler->IsProfiling()) return;
-    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
-    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
-  }
-
-  void SendProfilingSignal(int tid) {
-    if (!signal_handler_installed_) return;
-    // Glibc doesn't provide a wrapper for tgkill(2).
-#if defined(ANDROID)
-    syscall(__NR_tgkill, vm_tgid_, tid, SIGPROF);
-#else
-    int result = syscall(SYS_tgkill, vm_tgid_, tid, SIGPROF);
-    USE(result);
-    ASSERT(result == 0);
-#endif
-  }
-
-  void Sleep() {
-    // Convert ms to us and subtract 100 us to compensate delays
-    // occuring during signal delivery.
-    useconds_t interval = interval_ * 1000 - 100;
-#if defined(ANDROID)
-    usleep(interval);
-#else
-    int result = usleep(interval);
-#ifdef DEBUG
-    if (result != 0 && errno != EINTR) {
-      fprintf(stderr,
-              "SignalSender usleep error; interval = %u, errno = %d\n",
-              interval,
-              errno);
-      ASSERT(result == 0 || errno == EINTR);
-    }
-#endif  // DEBUG
-    USE(result);
-#endif  // ANDROID
-  }
-
-  const int vm_tgid_;
-  const int interval_;
-
-  // Protects the process wide state below.
-  static Mutex* mutex_;
-  static SignalSender* instance_;
-  static bool signal_handler_installed_;
-  static struct sigaction old_signal_handler_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SignalSender);
-};
-
-
-Mutex* SignalSender::mutex_ = NULL;
-SignalSender* SignalSender::instance_ = NULL;
-struct sigaction SignalSender::old_signal_handler_;
-bool SignalSender::signal_handler_installed_ = false;
-
-
 void OS::SetUp() {
   // Seed the random number generator. We preserve microsecond resolution.
   uint64_t seed = Ticks() ^ (getpid() << 16);
@@ -1330,44 +1015,12 @@ void OS::SetUp() {
 #endif
   }
 #endif
-  SignalSender::SetUp();
 }
 
 
 void OS::TearDown() {
-  SignalSender::TearDown();
   delete limit_mutex;
 }
 
 
-Sampler::Sampler(Isolate* isolate, int interval)
-    : isolate_(isolate),
-      interval_(interval),
-      profiling_(false),
-      active_(false),
-      samples_taken_(0) {
-  data_ = new PlatformData;
-}
-
-
-Sampler::~Sampler() {
-  ASSERT(!IsActive());
-  delete data_;
-}
-
-
-void Sampler::Start() {
-  ASSERT(!IsActive());
-  SetActive(true);
-  SignalSender::AddActiveSampler(this);
-}
-
-
-void Sampler::Stop() {
-  ASSERT(IsActive());
-  SignalSender::RemoveActiveSampler(this);
-  SetActive(false);
-}
-
-
 } }  // namespace v8::internal
diff --git a/src/platform-openbsd.cc b/src/platform-openbsd.cc
index 4c29023..e1aff17 100644
--- a/src/platform-openbsd.cc
+++ b/src/platform-openbsd.cc
@@ -53,7 +53,6 @@
 
 #include "platform-posix.h"
 #include "platform.h"
-#include "simulator.h"
 #include "v8threads.h"
 #include "vm-state-inl.h"
 
@@ -729,260 +728,17 @@ Semaphore* OS::CreateSemaphore(int count) {
 }
 
 
-static pthread_t GetThreadID() {
-  return pthread_self();
-}
-
-
-class Sampler::PlatformData : public Malloced {
- public:
-  PlatformData()
-      : vm_tid_(GetThreadID()),
-        profiled_thread_id_(ThreadId::Current()) {}
-
-  pthread_t vm_tid() const { return vm_tid_; }
-  ThreadId profiled_thread_id() { return profiled_thread_id_; }
-
- private:
-  pthread_t vm_tid_;
-  ThreadId profiled_thread_id_;
-};
-
-
-static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
-  USE(info);
-  if (signal != SIGPROF) return;
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
-    // We require a fully initialized and entered isolate.
-    return;
-  }
-  if (v8::Locker::IsActive() &&
-      !isolate->thread_manager()->IsLockedByCurrentThread()) {
-    return;
-  }
-
-  Sampler* sampler = isolate->logger()->sampler();
-  if (sampler == NULL || !sampler->IsActive()) return;
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
-  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
-  Isolate::PerIsolateThreadData* per_thread_data = isolate->
-      FindPerThreadDataForThread(thread_id);
-  if (!per_thread_data) return;
-  Simulator* sim = per_thread_data->simulator();
-  // Check if there is active simulator before allocating TickSample.
-  if (!sim) return;
-#endif
-#endif  // USE_SIMULATOR
-
-  TickSample sample_obj;
-  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
-  if (sample == NULL) sample = &sample_obj;
-
-  // Extracting the sample from the context is extremely machine dependent.
-  sample->state = isolate->current_vm_state();
-  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
-#elif V8_TARGET_ARCH_MIPS
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
-#endif
-#else
-#ifdef __NetBSD__
-  mcontext_t& mcontext = ucontext->uc_mcontext;
-#if V8_HOST_ARCH_IA32
-  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_EIP]);
-  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_ESP]);
-  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_EBP]);
-#elif V8_HOST_ARCH_X64
-  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_RIP]);
-  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RSP]);
-  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RBP]);
-#endif  // V8_HOST_ARCH
-#else  // OpenBSD
-#if V8_HOST_ARCH_IA32
-  sample->pc = reinterpret_cast<Address>(ucontext->sc_eip);
-  sample->sp = reinterpret_cast<Address>(ucontext->sc_esp);
-  sample->fp = reinterpret_cast<Address>(ucontext->sc_ebp);
-#elif V8_HOST_ARCH_X64
-  sample->pc = reinterpret_cast<Address>(ucontext->sc_rip);
-  sample->sp = reinterpret_cast<Address>(ucontext->sc_rsp);
-  sample->fp = reinterpret_cast<Address>(ucontext->sc_rbp);
-#endif  // V8_HOST_ARCH
-#endif  // __NetBSD__
-#endif  // USE_SIMULATOR
-  sampler->SampleStack(sample);
-  sampler->Tick(sample);
-}
-
-
-class SignalSender : public Thread {
- public:
-  static const int kSignalSenderStackSize = 64 * KB;
-
-  explicit SignalSender(int interval)
-      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
-        vm_tgid_(getpid()),
-        interval_(interval) {}
-
-  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
-  static void TearDown() { delete mutex_; }
-
-  static void InstallSignalHandler() {
-    struct sigaction sa;
-    sa.sa_sigaction = ProfilerSignalHandler;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = SA_RESTART | SA_SIGINFO;
-    signal_handler_installed_ =
-        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
-  }
-
-  static void RestoreSignalHandler() {
-    if (signal_handler_installed_) {
-      sigaction(SIGPROF, &old_signal_handler_, 0);
-      signal_handler_installed_ = false;
-    }
-  }
-
-  static void AddActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::AddActiveSampler(sampler);
-    if (instance_ == NULL) {
-      // Start a thread that will send SIGPROF signal to VM threads,
-      // when CPU profiling will be enabled.
-      instance_ = new SignalSender(sampler->interval());
-      instance_->StartSynchronously();
-    } else {
-      ASSERT(instance_->interval_ == sampler->interval());
-    }
-  }
-
-  static void RemoveActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::RemoveActiveSampler(sampler);
-    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
-      instance_->Join();
-      delete instance_;
-      instance_ = NULL;
-      RestoreSignalHandler();
-    }
-  }
-
-  // Implement Thread::Run().
-  virtual void Run() {
-    SamplerRegistry::State state;
-    while ((state = SamplerRegistry::GetState()) !=
-           SamplerRegistry::HAS_NO_SAMPLERS) {
-      // When CPU profiling is enabled both JavaScript and C++ code is
-      // profiled. We must not suspend.
-      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
-        if (!signal_handler_installed_) InstallSignalHandler();
-        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
-      } else if (signal_handler_installed_) {
-        RestoreSignalHandler();
-      }
-      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
-    }
-  }
-
-  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
-    if (!sampler->IsProfiling()) return;
-    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
-    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
-  }
-
-  void SendProfilingSignal(pthread_t tid) {
-    if (!signal_handler_installed_) return;
-    pthread_kill(tid, SIGPROF);
-  }
-
-  void Sleep() {
-    // Convert ms to us and subtract 100 us to compensate delays
-    // occuring during signal delivery.
-    useconds_t interval = interval_ * 1000 - 100;
-    int result = usleep(interval);
-#ifdef DEBUG
-    if (result != 0 && errno != EINTR) {
-      fprintf(stderr,
-              "SignalSender usleep error; interval = %u, errno = %d\n",
-              interval,
-              errno);
-      ASSERT(result == 0 || errno == EINTR);
-    }
-#endif
-    USE(result);
-  }
-
-  const int vm_tgid_;
-  const int interval_;
-
-  // Protects the process wide state below.
-  static Mutex* mutex_;
-  static SignalSender* instance_;
-  static bool signal_handler_installed_;
-  static struct sigaction old_signal_handler_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SignalSender);
-};
-
-
-Mutex* SignalSender::mutex_ = NULL;
-SignalSender* SignalSender::instance_ = NULL;
-struct sigaction SignalSender::old_signal_handler_;
-bool SignalSender::signal_handler_installed_ = false;
-
-
 void OS::SetUp() {
   // Seed the random number generator. We preserve microsecond resolution.
   uint64_t seed = Ticks() ^ (getpid() << 16);
   srandom(static_cast<unsigned int>(seed));
   limit_mutex = CreateMutex();
-  SignalSender::SetUp();
 }
 
 
 void OS::TearDown() {
-  SignalSender::TearDown();
   delete limit_mutex;
 }
 
 
-Sampler::Sampler(Isolate* isolate, int interval)
-    : isolate_(isolate),
-      interval_(interval),
-      profiling_(false),
-      active_(false),
-      samples_taken_(0) {
-  data_ = new PlatformData;
-}
-
-
-Sampler::~Sampler() {
-  ASSERT(!IsActive());
-  delete data_;
-}
-
-
-void Sampler::Start() {
-  ASSERT(!IsActive());
-  SetActive(true);
-  SignalSender::AddActiveSampler(this);
-}
-
-
-void Sampler::Stop() {
-  ASSERT(IsActive());
-  SignalSender::RemoveActiveSampler(this);
-  SetActive(false);
-}
-
-
 } }  // namespace v8::internal
diff --git a/src/platform-solaris.cc b/src/platform-solaris.cc
index f2477eb..aeacab9 100644
--- a/src/platform-solaris.cc
+++ b/src/platform-solaris.cc
@@ -54,7 +54,6 @@
 
 #include "platform-posix.h"
 #include "platform.h"
-#include "simulator.h"
 #include "v8threads.h"
 #include "vm-state-inl.h"
 
@@ -662,198 +661,6 @@ Semaphore* OS::CreateSemaphore(int count) {
 }
 
 
-static pthread_t GetThreadID() {
-  return pthread_self();
-}
-
-
-class Sampler::PlatformData : public Malloced {
- public:
-  PlatformData()
-      : vm_tid_(GetThreadID()),
-        profiled_thread_id_(ThreadId::Current()) {}
-
-  pthread_t vm_tid() const { return vm_tid_; }
-  ThreadId profiled_thread_id() { return profiled_thread_id_; }
-
- private:
-  pthread_t vm_tid_;
-  ThreadId profiled_thread_id_;
-};
-
-
-static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
-  USE(info);
-  if (signal != SIGPROF) return;
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
-    // We require a fully initialized and entered isolate.
-    return;
-  }
-  if (v8::Locker::IsActive() &&
-      !isolate->thread_manager()->IsLockedByCurrentThread()) {
-    return;
-  }
-
-  Sampler* sampler = isolate->logger()->sampler();
-  if (sampler == NULL || !sampler->IsActive()) return;
-
-  TickSample sample_obj;
-  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
-  if (sample == NULL) sample = &sample_obj;
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
-  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
-  Isolate::PerIsolateThreadData* per_thread_data = isolate->
-      FindPerThreadDataForThread(thread_id);
-  if (!per_thread_data) return;
-  Simulator* sim = per_thread_data->simulator();
-  // Check if there is active simulator before allocating TickSample.
-  if (!sim) return;
-#endif
-#endif  // USE_SIMULATOR
-
-  // Extracting the sample from the context is extremely machine dependent.
-  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
-  mcontext_t& mcontext = ucontext->uc_mcontext;
-  sample->state = isolate->current_vm_state();
-
-#if defined(USE_SIMULATOR)
-#if V8_TARGET_ARCH_ARM
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
-#elif V8_TARGET_ARCH_MIPS
-  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
-  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
-  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
-#endif
-#else
-  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_PC]);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_SP]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_FP]);
-#endif  // USE_SIMULATOR
-
-  sampler->SampleStack(sample);
-  sampler->Tick(sample);
-}
-
-
-class SignalSender : public Thread {
- public:
-  static const int kSignalSenderStackSize = 64 * KB;
-
-  explicit SignalSender(int interval)
-      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
-        interval_(interval) {}
-
-  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
-  static void TearDown() { delete mutex_; }
-
-  static void InstallSignalHandler() {
-    struct sigaction sa;
-    sa.sa_sigaction = ProfilerSignalHandler;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = SA_RESTART | SA_SIGINFO;
-    signal_handler_installed_ =
-        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
-  }
-
-  static void RestoreSignalHandler() {
-    if (signal_handler_installed_) {
-      sigaction(SIGPROF, &old_signal_handler_, 0);
-      signal_handler_installed_ = false;
-    }
-  }
-
-  static void AddActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::AddActiveSampler(sampler);
-    if (instance_ == NULL) {
-      // Start a thread that will send SIGPROF signal to VM threads,
-      // when CPU profiling will be enabled.
-      instance_ = new SignalSender(sampler->interval());
-      instance_->StartSynchronously();
-    } else {
-      ASSERT(instance_->interval_ == sampler->interval());
-    }
-  }
-
-  static void RemoveActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
-    SamplerRegistry::RemoveActiveSampler(sampler);
-    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
-      instance_->Join();
-      delete instance_;
-      instance_ = NULL;
-      RestoreSignalHandler();
-    }
-  }
-
-  // Implement Thread::Run().
-  virtual void Run() {
-    SamplerRegistry::State state;
-    while ((state = SamplerRegistry::GetState()) !=
-           SamplerRegistry::HAS_NO_SAMPLERS) {
-      // When CPU profiling is enabled both JavaScript and C++ code is
-      // profiled. We must not suspend.
-      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
-        if (!signal_handler_installed_) InstallSignalHandler();
-        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
-      } else if (signal_handler_installed_) {
-        RestoreSignalHandler();
-      }
-      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
-    }
-  }
-
-  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
-    if (!sampler->IsProfiling()) return;
-    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
-    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
-  }
-
-  void SendProfilingSignal(pthread_t tid) {
-    if (!signal_handler_installed_) return;
-    pthread_kill(tid, SIGPROF);
-  }
-
-  void Sleep() {
-    // Convert ms to us and subtract 100 us to compensate delays
-    // occuring during signal delivery.
-    useconds_t interval = interval_ * 1000 - 100;
-    int result = usleep(interval);
-#ifdef DEBUG
-    if (result != 0 && errno != EINTR) {
-      fprintf(stderr,
-              "SignalSender usleep error; interval = %u, errno = %d\n",
-              interval,
-              errno);
-      ASSERT(result == 0 || errno == EINTR);
-    }
-#endif
-    USE(result);
-  }
-
-  const int interval_;
-
-  // Protects the process wide state below.
-  static Mutex* mutex_;
-  static SignalSender* instance_;
-  static bool signal_handler_installed_;
-  static struct sigaction old_signal_handler_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SignalSender);
-};
-
-Mutex* SignalSender::mutex_ = NULL;
-SignalSender* SignalSender::instance_ = NULL;
-struct sigaction SignalSender::old_signal_handler_;
-bool SignalSender::signal_handler_installed_ = false;
-
-
 void OS::SetUp() {
   // Seed the random number generator.
   // Convert the current time to a 64-bit integer first, before converting it
@@ -863,43 +670,12 @@ void OS::SetUp() {
   uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
   srandom(static_cast<unsigned int>(seed));
   limit_mutex = CreateMutex();
-  SignalSender::SetUp();
 }
 
 
 void OS::TearDown() {
-  SignalSender::TearDown();
   delete limit_mutex;
 }
 
 
-Sampler::Sampler(Isolate* isolate, int interval)
-    : isolate_(isolate),
-      interval_(interval),
-      profiling_(false),
-      active_(false),
-      samples_taken_(0) {
-  data_ = new PlatformData;
-}
-
-
-Sampler::~Sampler() {
-  ASSERT(!IsActive());
-  delete data_;
-}
-
-
-void Sampler::Start() {
-  ASSERT(!IsActive());
-  SetActive(true);
-  SignalSender::AddActiveSampler(this);
-}
-
-
-void Sampler::Stop() {
-  ASSERT(IsActive());
-  SignalSender::RemoveActiveSampler(this);
-  SetActive(false);
-}
-
 } }  // namespace v8::internal
diff --git a/src/platform.h b/src/platform.h
index 3aeb38e..8551616 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -99,20 +99,13 @@ int random();
 #include "atomicops.h"
 #include "lazy-instance.h"
 #include "platform-tls.h"
+#include "sampler.h"
 #include "utils.h"
 #include "v8globals.h"
 
 namespace v8 {
 namespace internal {
 
-// Use AtomicWord for a machine-sized pointer. It is assumed that
-// reads and writes of naturally aligned values of this type are atomic.
-#if defined(__OpenBSD__) && defined(__i386__)
-typedef Atomic32 AtomicWord;
-#else
-typedef intptr_t AtomicWord;
-#endif
-
 class Semaphore;
 class Mutex;
 
@@ -727,91 +720,6 @@ class Socket {
 };
 
 
-// ----------------------------------------------------------------------------
-// Sampler
-//
-// A sampler periodically samples the state of the VM and optionally
-// (if used for profiling) the program counter and stack pointer for
-// the thread that created it.
-
-// TickSample captures the information collected for each sample.
-class TickSample {
- public:
-  TickSample()
-      : state(OTHER),
-        pc(NULL),
-        sp(NULL),
-        fp(NULL),
-        external_callback(NULL),
-        frames_count(0) {}
-  StateTag state;  // The state of the VM.
-  Address pc;      // Instruction pointer.
-  Address sp;      // Stack pointer.
-  Address fp;      // Frame pointer.
-  Address external_callback;
-  static const int kMaxFramesCount = 64;
-  Address stack[kMaxFramesCount];  // Call stack.
-  int frames_count : 8;  // Number of captured frames.
-};
-
-class Sampler {
- public:
-  // Initialize sampler.
-  Sampler(Isolate* isolate, int interval);
-  virtual ~Sampler();
-
-  int interval() const { return interval_; }
-
-  // Performs stack sampling.
-  void SampleStack(TickSample* sample) {
-    DoSampleStack(sample);
-    IncSamplesTaken();
-  }
-
-  // This method is called for each sampling period with the current
-  // program counter.
-  virtual void Tick(TickSample* sample) = 0;
-
-  // Start and stop sampler.
-  void Start();
-  void Stop();
-
-  // Is the sampler used for profiling?
-  bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
-  void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); }
-  void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); }
-
-  // Whether the sampler is running (that is, consumes resources).
-  bool IsActive() const { return NoBarrier_Load(&active_); }
-
-  Isolate* isolate() { return isolate_; }
-
-  // Used in tests to make sure that stack sampling is performed.
-  int samples_taken() const { return samples_taken_; }
-  void ResetSamplesTaken() { samples_taken_ = 0; }
-
-  class PlatformData;
-  PlatformData* data() { return data_; }
-
-  PlatformData* platform_data() { return data_; }
-
- protected:
-  virtual void DoSampleStack(TickSample* sample) = 0;
-
- private:
-  void SetActive(bool value) { NoBarrier_Store(&active_, value); }
-  void IncSamplesTaken() { if (++samples_taken_ < 0) samples_taken_ = 0; }
-
-  Isolate* isolate_;
-  const int interval_;
-  Atomic32 profiling_;
-  Atomic32 active_;
-  PlatformData* data_;  // Platform specific data.
-  int samples_taken_;  // Counts stack samples taken.
-  DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
-};
-
-
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_
diff --git a/src/sampler.cc b/src/sampler.cc
new file mode 100644
index 0000000..446f996
--- /dev/null
+++ b/src/sampler.cc
@@ -0,0 +1,480 @@
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
+    || defined(__NetBSD__) || defined(__sun)
+
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/syscall.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+#endif
+
+// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
+// Old versions of the C library <signal.h> didn't define the type.
+#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
+    defined(__arm__) && !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
+#include <asm/sigcontext.h>
+#endif
+
+#include "v8.h"
+
+#include "log.h"
+#include "platform.h"
+#include "simulator.h"
+#include "v8threads.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
+    || defined(__NetBSD__) || defined(__sun)
+
+#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T)
+
+// Not all versions of Android's C library provide ucontext_t.
+// Detect this and provide custom but compatible definitions. Note that these
+// follow the GLibc naming convention to access register values from
+// mcontext_t.
+//
+// See http://code.google.com/p/android/issues/detail?id=34784
+
+#if defined(__arm__)
+
+typedef struct sigcontext mcontext_t;
+
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+
+#elif defined(__mips__)
+// MIPS version of sigcontext, for Android bionic.
+typedef struct {
+  uint32_t regmask;
+  uint32_t status;
+  uint64_t pc;
+  uint64_t gregs[32];
+  uint64_t fpregs[32];
+  uint32_t acx;
+  uint32_t fpc_csr;
+  uint32_t fpc_eir;
+  uint32_t used_math;
+  uint32_t dsp;
+  uint64_t mdhi;
+  uint64_t mdlo;
+  uint32_t hi1;
+  uint32_t lo1;
+  uint32_t hi2;
+  uint32_t lo2;
+  uint32_t hi3;
+  uint32_t lo3;
+} mcontext_t;
+
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+
+#elif defined(__i386__)
+// x86 version for Android.
+typedef struct {
+  uint32_t gregs[19];
+  void* fpregs;
+  uint32_t oldmask;
+  uint32_t cr2;
+} mcontext_t;
+
+typedef uint32_t kernel_sigset_t[2];  // x86 kernel uses 64-bit signal masks
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
+#endif
+
+#endif  // __ANDROID__ && !defined(__BIONIC_HAVE_UCONTEXT_T)
+
+
+static pthread_t GetThreadID() {
+#if defined(__ANDROID__)
+  // Android's C library provides gettid(2).
+  return gettid();
+#elif defined(__linux__)
+  // Glibc doesn't provide a wrapper for gettid(2).
+  return syscall(SYS_gettid);
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+    || defined(__sun)
+  return pthread_self();
+#endif
+}
+
+
+class Sampler::PlatformData : public Malloced {
+ public:
+  PlatformData()
+      : vm_tid_(GetThreadID()),
+        profiled_thread_id_(ThreadId::Current()) {}
+
+  pthread_t vm_tid() const { return vm_tid_; }
+  ThreadId profiled_thread_id() { return profiled_thread_id_; }
+
+ private:
+  pthread_t vm_tid_;
+  ThreadId profiled_thread_id_;
+};
+
+
+static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
+#if defined(__native_client__)
+  // As Native Client does not support signal handling, profiling
+  // is disabled.
+  return;
+#else
+  USE(info);
+  if (signal != SIGPROF) return;
+  Isolate* isolate = Isolate::UncheckedCurrent();
+  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
+    // We require a fully initialized and entered isolate.
+    return;
+  }
+  if (v8::Locker::IsActive() &&
+      !isolate->thread_manager()->IsLockedByCurrentThread()) {
+    return;
+  }
+
+  Sampler* sampler = isolate->logger()->sampler();
+  if (sampler == NULL || !sampler->IsActive()) return;
+
+#if defined(USE_SIMULATOR)
+#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
+  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
+  Isolate::PerIsolateThreadData* per_thread_data = isolate->
+      FindPerThreadDataForThread(thread_id);
+  if (!per_thread_data) return;
+  Simulator* sim = per_thread_data->simulator();
+  // Check if there is active simulator before allocating TickSample.
+  if (!sim) return;
+#endif
+#endif  // USE_SIMULATOR
+
+  TickSample sample_obj;
+  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
+  if (sample == NULL) sample = &sample_obj;
+
+#if defined(USE_SIMULATOR)
+#if V8_TARGET_ARCH_ARM
+  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
+  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
+  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
+#elif V8_TARGET_ARCH_MIPS
+  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
+  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
+  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
+#endif  // V8_TARGET_ARCH_*
+#else
+  // Extracting the sample from the context is extremely machine dependent.
+  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+  mcontext_t& mcontext = ucontext->uc_mcontext;
+  sample->state = isolate->current_vm_state();
+#if defined(__linux__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
+#elif V8_HOST_ARCH_ARM
+#if defined(__GLIBC__) && !defined(__UCLIBC__) && \
+    (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+  // Old GLibc ARM versions used a gregs[] array to access the register
+  // values from mcontext_t.
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
+#else
+  sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
+  sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
+  sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
+#endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
+        // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+#elif V8_HOST_ARCH_MIPS
+  sample->pc = reinterpret_cast<Address>(mcontext.pc);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[29]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[30]);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__FreeBSD__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_eip);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_esp);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_ebp);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_rip);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_rsp);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_rbp);
+#elif V8_HOST_ARCH_ARM
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_r15);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_r13);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_r11);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__NetBSD__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_EIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_ESP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_RIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RSP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RBP]);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__OpenBSD__)
+  USE(mcontext);
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(ucontext->sc_eip);
+  sample->sp = reinterpret_cast<Address>(ucontext->sc_esp);
+  sample->fp = reinterpret_cast<Address>(ucontext->sc_ebp);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(ucontext->sc_rip);
+  sample->sp = reinterpret_cast<Address>(ucontext->sc_rsp);
+  sample->fp = reinterpret_cast<Address>(ucontext->sc_rbp);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__sun)
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_PC]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_SP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_FP]);
+#endif  // __sun
+#endif  // USE_SIMULATOR
+
+  sampler->SampleStack(sample);
+  sampler->Tick(sample);
+#endif  // __native_client__
+}
+
+
+class SignalSender : public Thread {
+ public:
+  static const int kSignalSenderStackSize = 64 * KB;
+
+  explicit SignalSender(int interval)
+      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
+        vm_tgid_(getpid()),
+        interval_(interval) {}
+
+  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
+  static void TearDown() { delete mutex_; }
+
+  static void InstallSignalHandler() {
+    struct sigaction sa;
+    sa.sa_sigaction = ProfilerSignalHandler;
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = SA_RESTART | SA_SIGINFO;
+    signal_handler_installed_ =
+        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
+  }
+
+  static void RestoreSignalHandler() {
+    if (signal_handler_installed_) {
+      sigaction(SIGPROF, &old_signal_handler_, 0);
+      signal_handler_installed_ = false;
+    }
+  }
+
+  static void AddActiveSampler(Sampler* sampler) {
+    ScopedLock lock(mutex_);
+    SamplerRegistry::AddActiveSampler(sampler);
+    if (instance_ == NULL) {
+      // Start a thread that will send SIGPROF signal to VM threads,
+      // when CPU profiling will be enabled.
+      instance_ = new SignalSender(sampler->interval());
+      instance_->StartSynchronously();
+    } else {
+      ASSERT(instance_->interval_ == sampler->interval());
+    }
+  }
+
+  static void RemoveActiveSampler(Sampler* sampler) {
+    ScopedLock lock(mutex_);
+    SamplerRegistry::RemoveActiveSampler(sampler);
+    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
+      instance_->Join();
+      delete instance_;
+      instance_ = NULL;
+      RestoreSignalHandler();
+    }
+  }
+
+  // Implement Thread::Run().
+  virtual void Run() {
+    SamplerRegistry::State state;
+    while ((state = SamplerRegistry::GetState()) !=
+           SamplerRegistry::HAS_NO_SAMPLERS) {
+      // When CPU profiling is enabled both JavaScript and C++ code is
+      // profiled. We must not suspend.
+      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
+        if (!signal_handler_installed_) InstallSignalHandler();
+        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
+      } else {
+        if (signal_handler_installed_) RestoreSignalHandler();
+      }
+      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
+    }
+  }
+
+  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
+    if (!sampler->IsProfiling()) return;
+    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
+    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
+  }
+
+  void SendProfilingSignal(int tid) {
+    if (!signal_handler_installed_) return;
+    // Glibc doesn't provide a wrapper for tgkill(2).
+#if defined(ANDROID)
+    syscall(__NR_tgkill, vm_tgid_, tid, SIGPROF);
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+    || defined(__sun)
+    pthread_kill(tid, SIGPROF);
+#else
+    int result = syscall(SYS_tgkill, vm_tgid_, tid, SIGPROF);
+    USE(result);
+    ASSERT(result == 0);
+#endif
+  }
+
+  void Sleep() {
+    // Convert ms to us and subtract 100 us to compensate delays
+    // occuring during signal delivery.
+    useconds_t interval = interval_ * 1000 - 100;
+#if defined(ANDROID)
+    usleep(interval);
+#else
+    int result = usleep(interval);
+#ifdef DEBUG
+    if (result != 0 && errno != EINTR) {
+      fprintf(stderr,
+              "SignalSender usleep error; interval = %u, errno = %d\n",
+              interval,
+              errno);
+      ASSERT(result == 0 || errno == EINTR);
+    }
+#endif  // DEBUG
+    USE(result);
+#endif  // ANDROID
+  }
+
+  const int vm_tgid_;
+  const int interval_;
+
+  // Protects the process wide state below.
+  static Mutex* mutex_;
+  static SignalSender* instance_;
+  static bool signal_handler_installed_;
+  static struct sigaction old_signal_handler_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SignalSender);
+};
+
+
+Mutex* SignalSender::mutex_ = NULL;
+SignalSender* SignalSender::instance_ = NULL;
+struct sigaction SignalSender::old_signal_handler_;
+bool SignalSender::signal_handler_installed_ = false;
+
+
+void Sampler::SetUp() {
+  SignalSender::SetUp();
+}
+
+
+void Sampler::TearDown() {
+  SignalSender::TearDown();
+}
+
+
+Sampler::Sampler(Isolate* isolate, int interval)
+    : isolate_(isolate),
+      interval_(interval),
+      profiling_(false),
+      active_(false),
+      samples_taken_(0) {
+  data_ = new PlatformData;
+}
+
+
+Sampler::~Sampler() {
+  ASSERT(!IsActive());
+  delete data_;
+}
+
+void Sampler::Start() {
+  ASSERT(!IsActive());
+  SetActive(true);
+  SignalSender::AddActiveSampler(this);
+}
+
+
+void Sampler::Stop() {
+  ASSERT(IsActive());
+  SignalSender::RemoveActiveSampler(this);
+  SetActive(false);
+}
+
+#else
+
+void Sampler::SetUp() {
+}
+
+
+void Sampler::TearDown() {
+}
+
+#endif  // __linux__ || _*BSD__ || __sun
+
+void Sampler::SampleStack(TickSample* sample) {
+  StackTracer::Trace(isolate_, sample);
+  if (++samples_taken_ < 0) samples_taken_ = 0;
+}
+
+} }  // namespace v8::internal
diff --git a/src/sampler.h b/src/sampler.h
new file mode 100644
index 0000000..2b8b75d
--- /dev/null
+++ b/src/sampler.h
@@ -0,0 +1,119 @@
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_SAMPLER_H_
+#define V8_SAMPLER_H_
+
+#include "atomicops.h"
+#include "v8globals.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+
+// ----------------------------------------------------------------------------
+// Sampler
+//
+// A sampler periodically samples the state of the VM and optionally
+// (if used for profiling) the program counter and stack pointer for
+// the thread that created it.
+
+// TickSample captures the information collected for each sample.
+struct TickSample {
+  TickSample()
+      : state(OTHER),
+        pc(NULL),
+        sp(NULL),
+        fp(NULL),
+        external_callback(NULL),
+        frames_count(0) {}
+  StateTag state;  // The state of the VM.
+  Address pc;      // Instruction pointer.
+  Address sp;      // Stack pointer.
+  Address fp;      // Frame pointer.
+  Address external_callback;
+  static const int kMaxFramesCount = 64;
+  Address stack[kMaxFramesCount];  // Call stack.
+  int frames_count : 8;  // Number of captured frames.
+};
+
+class Sampler {
+ public:
+  // Initializes the Sampler support. Called once at VM startup.
+  static void SetUp();
+  static void TearDown();
+
+  // Initialize sampler.
+  Sampler(Isolate* isolate, int interval);
+  virtual ~Sampler();
+
+  Isolate* isolate() const { return isolate_; }
+  int interval() const { return interval_; }
+
+  // Performs stack sampling.
+  void SampleStack(TickSample* sample);
+
+  // This method is called for each sampling period with the current
+  // program counter.
+  virtual void Tick(TickSample* sample) = 0;
+
+  // Start and stop sampler.
+  void Start();
+  void Stop();
+
+  // Is the sampler used for profiling?
+  bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
+  void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); }
+  void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); }
+
+  // Whether the sampler is running (that is, consumes resources).
+  bool IsActive() const { return NoBarrier_Load(&active_); }
+
+  // Used in tests to make sure that stack sampling is performed.
+  int samples_taken() const { return samples_taken_; }
+  void ResetSamplesTaken() { samples_taken_ = 0; }
+
+  class PlatformData;
+  PlatformData* platform_data() const { return data_; }
+
+ private:
+  void SetActive(bool value) { NoBarrier_Store(&active_, value); }
+
+  Isolate* isolate_;
+  const int interval_;
+  Atomic32 profiling_;
+  Atomic32 active_;
+  PlatformData* data_;  // Platform specific data.
+  int samples_taken_;  // Counts stack samples taken.
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_SAMPLER_H_
diff --git a/src/v8.cc b/src/v8.cc
index df92690..494bb30 100644
--- a/src/v8.cc
+++ b/src/v8.cc
@@ -41,6 +41,7 @@
 #include "objects.h"
 #include "once.h"
 #include "platform.h"
+#include "sampler.h"
 #include "runtime-profiler.h"
 #include "serialize.h"
 #include "store-buffer.h"
@@ -123,6 +124,7 @@ void V8::TearDown() {
   delete call_completed_callbacks_;
   call_completed_callbacks_ = NULL;
 
+  Sampler::TearDown();
   OS::TearDown();
 }
 
@@ -270,6 +272,7 @@ void V8::InitializeOncePerProcessImpl() {
   }
   if (FLAG_trace_hydrogen) FLAG_parallel_recompilation = false;
   OS::SetUp();
+  Sampler::SetUp();
   CPU::SetUp();
   use_crankshaft_ = FLAG_crankshaft
       && !Serializer::enabled()
diff --git a/src/v8globals.h b/src/v8globals.h
index 02010b9..82e30f5 100644
--- a/src/v8globals.h
+++ b/src/v8globals.h
@@ -163,7 +163,6 @@ class RelocInfo;
 class Deserializer;
 class MessageLocation;
 class ObjectGroup;
-class TickSample;
 class VirtualMemory;
 class Mutex;
 
diff --git a/tools/gyp/v8.gyp b/tools/gyp/v8.gyp
index 4522187..7233dfe 100644
--- a/tools/gyp/v8.gyp
+++ b/tools/gyp/v8.gyp
@@ -447,6 +447,8 @@
             '../../src/runtime.h',
             '../../src/safepoint-table.cc',
             '../../src/safepoint-table.h',
+            '../../src/sampler.cc',
+            '../../src/sampler.h',
             '../../src/scanner-character-streams.cc',
             '../../src/scanner-character-streams.h',
             '../../src/scanner.cc',