Split TickSample and Sampler.

src/profiler/tick-sample.cc

Index: src/profiler/tick-sample.cc
diff --git a/src/profiler/sampler.cc b/src/profiler/tick-sample.cc
similarity index 25%
copy from src/profiler/sampler.cc
copy to src/profiler/tick-sample.cc
index 055c9c83292ff99b4b4c8353b4656a2ed00f2825..3edd964c86d56bd8ec881007050241d7fbb3b632 100644
--- a/src/profiler/sampler.cc
+++ b/src/profiler/tick-sample.cc
@@ -2,179 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "src/profiler/sampler.h"
+#include "src/profiler/tick-sample.h"
 
-#if V8_OS_POSIX && !V8_OS_CYGWIN
-
-#define USE_SIGNALS
-
-#include <errno.h>
-#include <pthread.h>
-#include <signal.h>
-#include <sys/time.h>
-
-#if !V8_OS_QNX && !V8_OS_NACL && !V8_OS_AIX
-#include <sys/syscall.h>  // NOLINT
-#endif
-
-#if V8_OS_MACOSX
-#include <mach/mach.h>
-// OpenBSD doesn't have <ucontext.h>. ucontext_t lives in <signal.h>
-// and is a typedef for struct sigcontext. There is no uc_mcontext.
-#elif(!V8_OS_ANDROID || defined(__BIONIC_HAVE_UCONTEXT_T)) && \
-    !V8_OS_OPENBSD && !V8_OS_NACL
-#include <ucontext.h>
-#endif
-
-#include <unistd.h>
-
-// 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 V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
-    (defined(__arm__) || defined(__aarch64__)) && \
-    !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
-#include <asm/sigcontext.h>  // NOLINT
-#endif
-
-#elif V8_OS_WIN || V8_OS_CYGWIN
-
-#include "src/base/win32-headers.h"
-
-#endif
-
-#include "src/base/atomic-utils.h"
-#include "src/base/platform/platform.h"
-#include "src/flags.h"
 #include "src/frames-inl.h"
-#include "src/log.h"
-#include "src/profiler/cpu-profiler-inl.h"
-#include "src/simulator.h"
-#include "src/v8threads.h"
 #include "src/vm-state-inl.h"
 
 
-#if V8_OS_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(__aarch64__)
-
-typedef struct sigcontext mcontext_t;
-
-typedef struct ucontext {
-  uint64_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 };
-
-#elif defined(__x86_64__)
-// x64 version for Android.
-typedef struct {
-  uint64_t gregs[23];
-  void* fpregs;
-  uint64_t __reserved1[8];
-} mcontext_t;
-
-typedef struct ucontext {
-  uint64_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_RBP = 10, REG_RSP = 15, REG_RIP = 16 };
-#endif
-
-#endif  // V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
-
-
 namespace v8 {
 namespace internal {
 
 namespace {
 
-class PlatformDataCommon : public Malloced {
- public:
-  PlatformDataCommon() : profiled_thread_id_(ThreadId::Current()) {}
-  ThreadId profiled_thread_id() { return profiled_thread_id_; }
-
- protected:
-  ~PlatformDataCommon() {}
-
- private:
-  ThreadId profiled_thread_id_;
-};
-
-
 bool IsSamePage(byte* ptr1, byte* ptr2) {
   const uint32_t kPageSize = 4096;
   uintptr_t mask = ~static_cast<uintptr_t>(kPageSize - 1);
@@ -237,579 +75,8 @@ bool IsNoFrameRegion(Address address) {
   return false;
 }
 
-typedef List<Sampler*> SamplerList;
-
-#if defined(USE_SIGNALS)
-class AtomicGuard {
- public:
-  explicit AtomicGuard(base::AtomicValue<int>* atomic, bool is_block = true)
-      : atomic_(atomic),
-        is_success_(false) {
-    do {
-      // Use Acquire_Load to gain mutual exclusion.
-      USE(atomic_->Value());
-      is_success_ = atomic_->TrySetValue(0, 1);
-    } while (is_block && !is_success_);
-  }
-
-  bool is_success() { return is_success_; }
-
-  ~AtomicGuard() {
-    if (is_success_) {
-      atomic_->SetValue(0);
-    }
-    atomic_ = NULL;
-  }
-
- private:
-  base::AtomicValue<int>* atomic_;
-  bool is_success_;
-};
-
-
-// Returns key for hash map.
-void* ThreadKey(pthread_t thread_id) {
-  return reinterpret_cast<void*>(thread_id);
-}
-
-
-// Returns hash value for hash map.
-uint32_t ThreadHash(pthread_t thread_id) {
-#if V8_OS_MACOSX
-  return static_cast<uint32_t>(reinterpret_cast<intptr_t>(thread_id));
-#else
-  return static_cast<uint32_t>(thread_id);
-#endif
-}
-#endif  // USE_SIGNALS
-
 }  // namespace
 
-#if defined(USE_SIGNALS)
-
-class Sampler::PlatformData : public PlatformDataCommon {
- public:
-  PlatformData() : vm_tid_(pthread_self()) {}
-  pthread_t vm_tid() const { return vm_tid_; }
-
- private:
-  pthread_t vm_tid_;
-};
-
-#elif V8_OS_WIN || V8_OS_CYGWIN
-
-// ----------------------------------------------------------------------------
-// Win32 profiler support. On Cygwin we use the same sampler implementation as
-// on Win32.
-
-class Sampler::PlatformData : public PlatformDataCommon {
- public:
-  // Get a handle to the calling thread. This is the thread that we are
-  // going to profile. We need to make a copy of the handle because we are
-  // going to use it in the sampler thread. Using GetThreadHandle() will
-  // not work in this case. We're using OpenThread because DuplicateHandle
-  // for some reason doesn't work in Chrome's sandbox.
-  PlatformData()
-      : profiled_thread_(OpenThread(THREAD_GET_CONTEXT |
-                                    THREAD_SUSPEND_RESUME |
-                                    THREAD_QUERY_INFORMATION,
-                                    false,
-                                    GetCurrentThreadId())) {}
-
-  ~PlatformData() {
-    if (profiled_thread_ != NULL) {
-      CloseHandle(profiled_thread_);
-      profiled_thread_ = NULL;
-    }
-  }
-
-  HANDLE profiled_thread() { return profiled_thread_; }
-
- private:
-  HANDLE profiled_thread_;
-};
-#endif
-
-
-#if defined(USE_SIMULATOR)
-bool SimulatorHelper::FillRegisters(Isolate* isolate,
-                                    v8::RegisterState* state) {
-  Simulator *simulator = isolate->thread_local_top()->simulator_;
-  // Check if there is active simulator.
-  if (simulator == NULL) return false;
-#if V8_TARGET_ARCH_ARM
-  if (!simulator->has_bad_pc()) {
-    state->pc = reinterpret_cast<Address>(simulator->get_pc());
-  }
-  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
-  state->fp = reinterpret_cast<Address>(simulator->get_register(
-      Simulator::r11));
-#elif V8_TARGET_ARCH_ARM64
-  state->pc = reinterpret_cast<Address>(simulator->pc());
-  state->sp = reinterpret_cast<Address>(simulator->sp());
-  state->fp = reinterpret_cast<Address>(simulator->fp());
-#elif V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64
-  if (!simulator->has_bad_pc()) {
-    state->pc = reinterpret_cast<Address>(simulator->get_pc());
-  }
-  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
-  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
-#elif V8_TARGET_ARCH_PPC
-  if (!simulator->has_bad_pc()) {
-    state->pc = reinterpret_cast<Address>(simulator->get_pc());
-  }
-  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
-  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
-#elif V8_TARGET_ARCH_S390
-  if (!simulator->has_bad_pc()) {
-    state->pc = reinterpret_cast<Address>(simulator->get_pc());
-  }
-  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
-  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
-#endif
-  if (state->sp == 0 || state->fp == 0) {
-    // It possible that the simulator is interrupted while it is updating
-    // the sp or fp register. ARM64 simulator does this in two steps:
-    // first setting it to zero and then setting it to the new value.
-    // Bailout if sp/fp doesn't contain the new value.
-    //
-    // FIXME: The above doesn't really solve the issue.
-    // If a 64-bit target is executed on a 32-bit host even the final
-    // write is non-atomic, so it might obtain a half of the result.
-    // Moreover as long as the register set code uses memcpy (as of now),
-    // it is not guaranteed to be atomic even when both host and target
-    // are of same bitness.
-    return false;
-  }
-  return true;
-}
-#endif  // USE_SIMULATOR
-
-
-#if defined(USE_SIGNALS)
-
-class SignalHandler : public AllStatic {
- public:
-  static void SetUp() { if (!mutex_) mutex_ = new base::Mutex(); }
-  static void TearDown() { delete mutex_; mutex_ = NULL; }
-
-  static void IncreaseSamplerCount() {
-    base::LockGuard<base::Mutex> lock_guard(mutex_);
-    if (++client_count_ == 1) Install();
-  }
-
-  static void DecreaseSamplerCount() {
-    base::LockGuard<base::Mutex> lock_guard(mutex_);
-    if (--client_count_ == 0) Restore();
-  }
-
-  static bool Installed() {
-    return signal_handler_installed_;
-  }
-
-#if !V8_OS_NACL
-  static void CollectSample(void* context, Sampler* sampler);
-#endif
-
- private:
-  static void Install() {
-#if !V8_OS_NACL
-    struct sigaction sa;
-    sa.sa_sigaction = &HandleProfilerSignal;
-    sigemptyset(&sa.sa_mask);
-#if V8_OS_QNX
-    sa.sa_flags = SA_SIGINFO;
-#else
-    sa.sa_flags = SA_RESTART | SA_SIGINFO;
-#endif
-    signal_handler_installed_ =
-        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
-#endif
-  }
-
-  static void Restore() {
-#if !V8_OS_NACL
-    if (signal_handler_installed_) {
-      sigaction(SIGPROF, &old_signal_handler_, 0);
-      signal_handler_installed_ = false;
-    }
-#endif
-  }
-
-#if !V8_OS_NACL
-  static void HandleProfilerSignal(int signal, siginfo_t* info, void* context);
-#endif
-  // Protects the process wide state below.
-  static base::Mutex* mutex_;
-  static int client_count_;
-  static bool signal_handler_installed_;
-  static struct sigaction old_signal_handler_;
-};
-
-
-base::Mutex* SignalHandler::mutex_ = NULL;
-int SignalHandler::client_count_ = 0;
-struct sigaction SignalHandler::old_signal_handler_;
-bool SignalHandler::signal_handler_installed_ = false;
-
-
-// As Native Client does not support signal handling, profiling is disabled.
-#if !V8_OS_NACL
-void SignalHandler::CollectSample(void* context, Sampler* sampler) {
-  if (sampler == NULL || (!sampler->IsProfiling() &&
-                          !sampler->IsRegistered())) {
-    return;
-  }
-  Isolate* isolate = sampler->isolate();
-
-  // We require a fully initialized and entered isolate.
-  if (isolate == NULL || !isolate->IsInUse()) return;
-
-  if (v8::Locker::IsActive() &&
-      !isolate->thread_manager()->IsLockedByCurrentThread()) {
-    return;
-  }
-
-  v8::RegisterState state;
-
-#if defined(USE_SIMULATOR)
-  if (!SimulatorHelper::FillRegisters(isolate, &state)) return;
-#else
-  // Extracting the sample from the context is extremely machine dependent.
-  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
-#if !(V8_OS_OPENBSD || (V8_OS_LINUX && (V8_HOST_ARCH_PPC || V8_HOST_ARCH_S390)))
-  mcontext_t& mcontext = ucontext->uc_mcontext;
-#endif
-#if V8_OS_LINUX
-#if V8_HOST_ARCH_IA32
-  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
-#elif V8_HOST_ARCH_X64
-  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
-#elif V8_HOST_ARCH_ARM
-#if V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4)
-  // Old GLibc ARM versions used a gregs[] array to access the register
-  // values from mcontext_t.
-  state.pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
-#else
-  state.pc = reinterpret_cast<Address>(mcontext.arm_pc);
-  state.sp = reinterpret_cast<Address>(mcontext.arm_sp);
-  state.fp = reinterpret_cast<Address>(mcontext.arm_fp);
-#endif  // V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4)
-#elif V8_HOST_ARCH_ARM64
-  state.pc = reinterpret_cast<Address>(mcontext.pc);
-  state.sp = reinterpret_cast<Address>(mcontext.sp);
-  // FP is an alias for x29.
-  state.fp = reinterpret_cast<Address>(mcontext.regs[29]);
-#elif V8_HOST_ARCH_MIPS
-  state.pc = reinterpret_cast<Address>(mcontext.pc);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[29]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[30]);
-#elif V8_HOST_ARCH_MIPS64
-  state.pc = reinterpret_cast<Address>(mcontext.pc);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[29]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[30]);
-#elif V8_HOST_ARCH_PPC
-  state.pc = reinterpret_cast<Address>(ucontext->uc_mcontext.regs->nip);
-  state.sp = reinterpret_cast<Address>(ucontext->uc_mcontext.regs->gpr[PT_R1]);
-  state.fp = reinterpret_cast<Address>(ucontext->uc_mcontext.regs->gpr[PT_R31]);
-#elif V8_HOST_ARCH_S390
-#if V8_TARGET_ARCH_32_BIT
-  // 31-bit target will have bit 0 (MSB) of the PSW set to denote addressing
-  // mode.  This bit needs to be masked out to resolve actual address.
-  state.pc =
-      reinterpret_cast<Address>(ucontext->uc_mcontext.psw.addr & 0x7FFFFFFF);
-#else
-  state.pc = reinterpret_cast<Address>(ucontext->uc_mcontext.psw.addr);
-#endif  // V8_TARGET_ARCH_32_BIT
-  state.sp = reinterpret_cast<Address>(ucontext->uc_mcontext.gregs[15]);
-  state.fp = reinterpret_cast<Address>(ucontext->uc_mcontext.gregs[11]);
-#endif  // V8_HOST_ARCH_*
-#elif V8_OS_MACOSX
-#if V8_HOST_ARCH_X64
-#if __DARWIN_UNIX03
-  state.pc = reinterpret_cast<Address>(mcontext->__ss.__rip);
-  state.sp = reinterpret_cast<Address>(mcontext->__ss.__rsp);
-  state.fp = reinterpret_cast<Address>(mcontext->__ss.__rbp);
-#else  // !__DARWIN_UNIX03
-  state.pc = reinterpret_cast<Address>(mcontext->ss.rip);
-  state.sp = reinterpret_cast<Address>(mcontext->ss.rsp);
-  state.fp = reinterpret_cast<Address>(mcontext->ss.rbp);
-#endif  // __DARWIN_UNIX03
-#elif V8_HOST_ARCH_IA32
-#if __DARWIN_UNIX03
-  state.pc = reinterpret_cast<Address>(mcontext->__ss.__eip);
-  state.sp = reinterpret_cast<Address>(mcontext->__ss.__esp);
-  state.fp = reinterpret_cast<Address>(mcontext->__ss.__ebp);
-#else  // !__DARWIN_UNIX03
-  state.pc = reinterpret_cast<Address>(mcontext->ss.eip);
-  state.sp = reinterpret_cast<Address>(mcontext->ss.esp);
-  state.fp = reinterpret_cast<Address>(mcontext->ss.ebp);
-#endif  // __DARWIN_UNIX03
-#endif  // V8_HOST_ARCH_IA32
-#elif V8_OS_FREEBSD
-#if V8_HOST_ARCH_IA32
-  state.pc = reinterpret_cast<Address>(mcontext.mc_eip);
-  state.sp = reinterpret_cast<Address>(mcontext.mc_esp);
-  state.fp = reinterpret_cast<Address>(mcontext.mc_ebp);
-#elif V8_HOST_ARCH_X64
-  state.pc = reinterpret_cast<Address>(mcontext.mc_rip);
-  state.sp = reinterpret_cast<Address>(mcontext.mc_rsp);
-  state.fp = reinterpret_cast<Address>(mcontext.mc_rbp);
-#elif V8_HOST_ARCH_ARM
-  state.pc = reinterpret_cast<Address>(mcontext.mc_r15);
-  state.sp = reinterpret_cast<Address>(mcontext.mc_r13);
-  state.fp = reinterpret_cast<Address>(mcontext.mc_r11);
-#endif  // V8_HOST_ARCH_*
-#elif V8_OS_NETBSD
-#if V8_HOST_ARCH_IA32
-  state.pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_EIP]);
-  state.sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_ESP]);
-  state.fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_EBP]);
-#elif V8_HOST_ARCH_X64
-  state.pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_RIP]);
-  state.sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RSP]);
-  state.fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RBP]);
-#endif  // V8_HOST_ARCH_*
-#elif V8_OS_OPENBSD
-#if V8_HOST_ARCH_IA32
-  state.pc = reinterpret_cast<Address>(ucontext->sc_eip);
-  state.sp = reinterpret_cast<Address>(ucontext->sc_esp);
-  state.fp = reinterpret_cast<Address>(ucontext->sc_ebp);
-#elif V8_HOST_ARCH_X64
-  state.pc = reinterpret_cast<Address>(ucontext->sc_rip);
-  state.sp = reinterpret_cast<Address>(ucontext->sc_rsp);
-  state.fp = reinterpret_cast<Address>(ucontext->sc_rbp);
-#endif  // V8_HOST_ARCH_*
-#elif V8_OS_SOLARIS
-  state.pc = reinterpret_cast<Address>(mcontext.gregs[REG_PC]);
-  state.sp = reinterpret_cast<Address>(mcontext.gregs[REG_SP]);
-  state.fp = reinterpret_cast<Address>(mcontext.gregs[REG_FP]);
-#elif V8_OS_QNX
-#if V8_HOST_ARCH_IA32
-  state.pc = reinterpret_cast<Address>(mcontext.cpu.eip);
-  state.sp = reinterpret_cast<Address>(mcontext.cpu.esp);
-  state.fp = reinterpret_cast<Address>(mcontext.cpu.ebp);
-#elif V8_HOST_ARCH_ARM
-  state.pc = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_PC]);
-  state.sp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_SP]);
-  state.fp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_FP]);
-#endif  // V8_HOST_ARCH_*
-#elif V8_OS_AIX
-  state.pc = reinterpret_cast<Address>(mcontext.jmp_context.iar);
-  state.sp = reinterpret_cast<Address>(mcontext.jmp_context.gpr[1]);
-  state.fp = reinterpret_cast<Address>(mcontext.jmp_context.gpr[31]);
-#endif  // V8_OS_AIX
-#endif  // USE_SIMULATOR
-  sampler->SampleStack(state);
-}
-#endif  // V8_OS_NACL
-
-#endif  // USE_SIGNALS
-
-
-class SamplerThread : public base::Thread {
- public:
-  static const int kSamplerThreadStackSize = 64 * KB;
-
-  explicit SamplerThread(int interval)
-      : Thread(base::Thread::Options("SamplerThread", kSamplerThreadStackSize)),
-        interval_(interval) {}
-
-  static void SetUp() { if (!mutex_) mutex_ = new base::Mutex(); }
-  static void TearDown() { delete mutex_; mutex_ = NULL; }
-
-  static void AddActiveSampler(Sampler* sampler) {
-    bool need_to_start = false;
-    base::LockGuard<base::Mutex> lock_guard(mutex_);
-    if (instance_ == NULL) {
-      // Start a thread that will send SIGPROF signal to VM threads,
-      // when CPU profiling will be enabled.
-      instance_ = new SamplerThread(sampler->interval());
-      need_to_start = true;
-    }
-
-    DCHECK(sampler->IsActive());
-    DCHECK(instance_->interval_ == sampler->interval());
-
-#if defined(USE_SIGNALS)
-    AddSampler(sampler);
-#else
-    DCHECK(!instance_->active_samplers_.Contains(sampler));
-    instance_->active_samplers_.Add(sampler);
-#endif  // USE_SIGNALS
-
-    if (need_to_start) instance_->StartSynchronously();
-  }
-
-  static void RemoveSampler(Sampler* sampler) {
-    SamplerThread* instance_to_remove = NULL;
-    {
-      base::LockGuard<base::Mutex> lock_guard(mutex_);
-
-      DCHECK(sampler->IsActive() || sampler->IsRegistered());
-#if defined(USE_SIGNALS)
-      {
-        AtomicGuard atomic_guard(&sampler_list_access_counter_);
-        // Remove sampler from map.
-        pthread_t thread_id = sampler->platform_data()->vm_tid();
-        void* thread_key = ThreadKey(thread_id);
-        uint32_t thread_hash = ThreadHash(thread_id);
-        HashMap::Entry* entry =
-            thread_id_to_samplers_.Get().Lookup(thread_key, thread_hash);
-        DCHECK(entry != NULL);
-        SamplerList* samplers = reinterpret_cast<SamplerList*>(entry->value);
-        samplers->RemoveElement(sampler);
-        if (samplers->is_empty()) {
-          thread_id_to_samplers_.Pointer()->Remove(thread_key, thread_hash);
-          delete samplers;
-        }
-        if (thread_id_to_samplers_.Get().occupancy() == 0) {
-          instance_to_remove = instance_;
-          instance_ = NULL;
-        }
-      }
-#else
-      bool removed = instance_->active_samplers_.RemoveElement(sampler);
-      DCHECK(removed);
-      USE(removed);
-
-      // We cannot delete the instance immediately as we need to Join() the
-      // thread but we are holding mutex_ and the thread may try to acquire it.
-      if (instance_->active_samplers_.is_empty()) {
-        instance_to_remove = instance_;
-        instance_ = NULL;
-      }
-#endif  // USE_SIGNALS
-    }
-
-    if (!instance_to_remove) return;
-    instance_to_remove->Join();
-    delete instance_to_remove;
-  }
-
-  // Unlike AddActiveSampler, this method only adds a sampler,
-  // but won't start the sampler thread.
-  static void RegisterSampler(Sampler* sampler) {
-    base::LockGuard<base::Mutex> lock_guard(mutex_);
-#if defined(USE_SIGNALS)
-    AddSampler(sampler);
-#endif  // USE_SIGNALS
-  }
-
-  // Implement Thread::Run().
-  virtual void Run() {
-    while (true) {
-      {
-        base::LockGuard<base::Mutex> lock_guard(mutex_);
-#if defined(USE_SIGNALS)
-        if (thread_id_to_samplers_.Get().occupancy() == 0) break;
-        if (SignalHandler::Installed()) {
-          for (HashMap::Entry *p = thread_id_to_samplers_.Get().Start();
-               p != NULL; p = thread_id_to_samplers_.Get().Next(p)) {
-#if V8_OS_AIX && V8_TARGET_ARCH_PPC64
-            // on AIX64, cannot cast (void *) to pthread_t which is
-            // of type unsigned int (4bytes)
-            pthread_t thread_id = reinterpret_cast<intptr_t>(p->key);
-#else
-            pthread_t thread_id = reinterpret_cast<pthread_t>(p->key);
-#endif
-            pthread_kill(thread_id, SIGPROF);
-          }
-        }
-#else
-        if (active_samplers_.is_empty()) break;
-        // When CPU profiling is enabled both JavaScript and C++ code is
-        // profiled. We must not suspend.
-        for (int i = 0; i < active_samplers_.length(); ++i) {
-          Sampler* sampler = active_samplers_.at(i);
-          if (!sampler->IsProfiling()) continue;
-          sampler->DoSample();
-        }
-#endif  // USE_SIGNALS
-      }
-      base::OS::Sleep(base::TimeDelta::FromMilliseconds(interval_));
-    }
-  }
-
- private:
-  // Protects the process wide state below.
-  static base::Mutex* mutex_;
-  static SamplerThread* instance_;
-
-  const int interval_;
-
-#if defined(USE_SIGNALS)
-  struct HashMapCreateTrait {
-    static void Construct(HashMap* allocated_ptr) {
-      new (allocated_ptr) HashMap(HashMap::PointersMatch);
-    }
-  };
-  friend class SignalHandler;
-  static base::LazyInstance<HashMap, HashMapCreateTrait>::type
-      thread_id_to_samplers_;
-  static base::AtomicValue<int> sampler_list_access_counter_;
-  static void AddSampler(Sampler* sampler) {
-    AtomicGuard atomic_guard(&sampler_list_access_counter_);
-    // Add sampler into map if needed.
-    pthread_t thread_id = sampler->platform_data()->vm_tid();
-    HashMap::Entry *entry =
-        thread_id_to_samplers_.Pointer()->LookupOrInsert(ThreadKey(thread_id),
-                                                         ThreadHash(thread_id));
-    if (entry->value == NULL) {
-      SamplerList* samplers = new SamplerList();
-      samplers->Add(sampler);
-      entry->value = samplers;
-    } else {
-      SamplerList* samplers = reinterpret_cast<SamplerList*>(entry->value);
-      if (!samplers->Contains(sampler)) {
-        samplers->Add(sampler);
-      }
-    }
-  }
-#else
-  SamplerList active_samplers_;
-#endif  // USE_SIGNALS
-
-  DISALLOW_COPY_AND_ASSIGN(SamplerThread);
-};
-
-
-base::Mutex* SamplerThread::mutex_ = NULL;
-SamplerThread* SamplerThread::instance_ = NULL;
-#if defined(USE_SIGNALS)
-base::LazyInstance<HashMap, SamplerThread::HashMapCreateTrait>::type
-    SamplerThread::thread_id_to_samplers_ = LAZY_INSTANCE_INITIALIZER;
-base::AtomicValue<int> SamplerThread::sampler_list_access_counter_(0);
-
-// As Native Client does not support signal handling, profiling is disabled.
-#if !V8_OS_NACL
-void SignalHandler::HandleProfilerSignal(int signal, siginfo_t* info,
-                                         void* context) {
-  USE(info);
-  if (signal != SIGPROF) return;
-  AtomicGuard atomic_guard(&SamplerThread::sampler_list_access_counter_, false);
-  if (!atomic_guard.is_success()) return;
-  pthread_t thread_id = pthread_self();
-  HashMap::Entry* entry =
-      SamplerThread::thread_id_to_samplers_.Pointer()->Lookup(
-          ThreadKey(thread_id), ThreadHash(thread_id));
-  if (entry == NULL)
-    return;
-  SamplerList* samplers = reinterpret_cast<SamplerList*>(entry->value);
-  for (int i = 0; i < samplers->length(); ++i) {
-    Sampler* sampler = samplers->at(i);
-    CollectSample(context, sampler);
-  }
-}
-#endif  // !V8_OS_NACL
-#endif  // USE_SIGNALs
-
 
 //
 // StackTracer implementation
@@ -908,138 +175,59 @@ void TickSample::GetStackSample(Isolate* isolate, const v8::RegisterState& regs,
 }
 
 
-void Sampler::SetUp() {
-#if defined(USE_SIGNALS)
-  SignalHandler::SetUp();
-#endif
-  SamplerThread::SetUp();
-}
-
-
-void Sampler::TearDown() {
-  SamplerThread::TearDown();
-#if defined(USE_SIGNALS)
-  SignalHandler::TearDown();
-#endif
-}
-
-Sampler::Sampler(Isolate* isolate, int interval)
-    : isolate_(isolate),
-      interval_(interval),
-      profiling_(false),
-      has_processing_thread_(false),
-      active_(false),
-      registered_(false),
-      is_counting_samples_(false),
-      js_sample_count_(0),
-      external_sample_count_(0) {
-  data_ = new PlatformData;
-}
-
-Sampler::~Sampler() {
-  DCHECK(!IsActive());
-  if (IsRegistered()) {
-    SamplerThread::RemoveSampler(this);
+#if defined(USE_SIMULATOR)
+bool SimulatorHelper::FillRegisters(Isolate* isolate,
+                                    v8::RegisterState* state) {
+  Simulator *simulator = isolate->thread_local_top()->simulator_;
+  // Check if there is active simulator.
+  if (simulator == NULL) return false;
+#if V8_TARGET_ARCH_ARM
+  if (!simulator->has_bad_pc()) {
+    state->pc = reinterpret_cast<Address>(simulator->get_pc());
   }
-  delete data_;
-}
-
-void Sampler::Start() {
-  DCHECK(!IsActive());
-  SetActive(true);
-  SamplerThread::AddActiveSampler(this);
-}
-
-
-void Sampler::Stop() {
-  DCHECK(IsActive());
-  SamplerThread::RemoveSampler(this);
-  SetActive(false);
-  SetRegistered(false);
-}
-
-
-void Sampler::IncreaseProfilingDepth() {
-  base::NoBarrier_AtomicIncrement(&profiling_, 1);
-#if defined(USE_SIGNALS)
-  SignalHandler::IncreaseSamplerCount();
-#endif
-}
-
-
-void Sampler::DecreaseProfilingDepth() {
-#if defined(USE_SIGNALS)
-  SignalHandler::DecreaseSamplerCount();
-#endif
-  base::NoBarrier_AtomicIncrement(&profiling_, -1);
-}
-
-
-void Sampler::SampleStack(const v8::RegisterState& state) {
-  TickSample* sample = isolate_->cpu_profiler()->StartTickSample();
-  TickSample sample_obj;
-  if (sample == NULL) sample = &sample_obj;
-  sample->Init(isolate_, state, TickSample::kIncludeCEntryFrame, true);
-  if (is_counting_samples_ && !sample->timestamp.IsNull()) {
-    if (sample->state == JS) ++js_sample_count_;
-    if (sample->state == EXTERNAL) ++external_sample_count_;
+  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
+  state->fp = reinterpret_cast<Address>(simulator->get_register(
+      Simulator::r11));
+#elif V8_TARGET_ARCH_ARM64
+  state->pc = reinterpret_cast<Address>(simulator->pc());
+  state->sp = reinterpret_cast<Address>(simulator->sp());
+  state->fp = reinterpret_cast<Address>(simulator->fp());
+#elif V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64
+  if (!simulator->has_bad_pc()) {
+    state->pc = reinterpret_cast<Address>(simulator->get_pc());
   }
-  Tick(sample);
-  if (sample != &sample_obj) {
-    isolate_->cpu_profiler()->FinishTickSample();
+  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
+  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
+#elif V8_TARGET_ARCH_PPC
+  if (!simulator->has_bad_pc()) {
+    state->pc = reinterpret_cast<Address>(simulator->get_pc());
   }
-}
-
-
-#if defined(USE_SIGNALS)
-
-void Sampler::DoSample() {
-  if (!SignalHandler::Installed()) return;
-  if (!IsActive() && !IsRegistered()) {
-    SamplerThread::RegisterSampler(this);
-    SetRegistered(true);
+  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
+  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
+#elif V8_TARGET_ARCH_S390
+  if (!simulator->has_bad_pc()) {
+    state->pc = reinterpret_cast<Address>(simulator->get_pc());
   }
-  pthread_kill(platform_data()->vm_tid(), SIGPROF);
-}
-
-#elif V8_OS_WIN || V8_OS_CYGWIN
-
-void Sampler::DoSample() {
-  HANDLE profiled_thread = platform_data()->profiled_thread();
-  if (profiled_thread == NULL) return;
-
-  const DWORD kSuspendFailed = static_cast<DWORD>(-1);
-  if (SuspendThread(profiled_thread) == kSuspendFailed) return;
-
-  // Context used for sampling the register state of the profiled thread.
-  CONTEXT context;
-  memset(&context, 0, sizeof(context));
-  context.ContextFlags = CONTEXT_FULL;
-  if (GetThreadContext(profiled_thread, &context) != 0) {
-    v8::RegisterState state;
-#if defined(USE_SIMULATOR)
-    if (!SimulatorHelper::FillRegisters(isolate(), &state)) {
-      ResumeThread(profiled_thread);
-      return;
-    }
-#else
-#if V8_HOST_ARCH_X64
-    state.pc = reinterpret_cast<Address>(context.Rip);
-    state.sp = reinterpret_cast<Address>(context.Rsp);
-    state.fp = reinterpret_cast<Address>(context.Rbp);
-#else
-    state.pc = reinterpret_cast<Address>(context.Eip);
-    state.sp = reinterpret_cast<Address>(context.Esp);
-    state.fp = reinterpret_cast<Address>(context.Ebp);
+  state->sp = reinterpret_cast<Address>(simulator->get_register(Simulator::sp));
+  state->fp = reinterpret_cast<Address>(simulator->get_register(Simulator::fp));
 #endif
-#endif  // USE_SIMULATOR
-    SampleStack(state);
+  if (state->sp == 0 || state->fp == 0) {
+    // It possible that the simulator is interrupted while it is updating
+    // the sp or fp register. ARM64 simulator does this in two steps:
+    // first setting it to zero and then setting it to the new value.
+    // Bailout if sp/fp doesn't contain the new value.
+    //
+    // FIXME: The above doesn't really solve the issue.
+    // If a 64-bit target is executed on a 32-bit host even the final
+    // write is non-atomic, so it might obtain a half of the result.
+    // Moreover as long as the register set code uses memcpy (as of now),
+    // it is not guaranteed to be atomic even when both host and target
+    // are of same bitness.
+    return false;
   }
-  ResumeThread(profiled_thread);
+  return true;
 }
-
-#endif  // USE_SIGNALS
-
+#endif  // USE_SIMULATOR
 
 }  // namespace internal
 }  // namespace v8