Move SimulatorHelper into V8 out of profiler clients.

Clients should not know about the simulator.

BUG=v8:4789

Review-Url: https://codereview.chromium.org/2128613004
Cr-Commit-Position: refs/heads/master@{#37617}

src/api.cc

@@ -7656,20 +7656,13 @@ bool Isolate::GetHeapCodeAndMetadataStatistics(
 
 void Isolate::GetStackSample(const RegisterState& state, void** frames,
                              size_t frames_limit, SampleInfo* sample_info) {
-#if defined(USE_SIMULATOR)
-  RegisterState regs;
-  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
-  if (!i::SimulatorHelper::FillRegisters(isolate, &regs)) {
-    sample_info->frames_count = 0;
-    sample_info->vm_state = OTHER;
-    sample_info->external_callback_entry = nullptr;
+  if (TickSample::GetStackSample(this, state, TickSample::kSkipCEntryFrame,
+                                 frames, frames_limit, sample_info)) {
     return;
   }
-#else
-  const RegisterState& regs = state;
-#endif
-  TickSample::GetStackSample(this, regs, TickSample::kSkipCEntryFrame, frames,
-                             frames_limit, sample_info);
+  sample_info->frames_count = 0;
+  sample_info->vm_state = OTHER;
+  sample_info->external_callback_entry = nullptr;
 }
 
 size_t Isolate::NumberOfPhantomHandleResetsSinceLastCall() {

src/log.cc

@@ -619,10 +619,10 @@ class Profiler: public base::Thread {
 //
 class Ticker: public sampler::Sampler {
  public:
-  Ticker(Isolate* isolate, int interval):
-      sampler::Sampler(reinterpret_cast<v8::Isolate*>(isolate)),
-      profiler_(NULL),
-      sampling_thread_(new SamplingThread(this, interval)) {}
+  Ticker(Isolate* isolate, int interval)
+      : sampler::Sampler(reinterpret_cast<v8::Isolate*>(isolate)),
+        profiler_(nullptr),
+        sampling_thread_(new SamplingThread(this, interval)) {}
 
   ~Ticker() {
     if (IsActive()) Stop();
@@ -630,7 +630,7 @@ class Ticker: public sampler::Sampler {
   }
 
   void SetProfiler(Profiler* profiler) {
-    DCHECK(profiler_ == NULL);
+    DCHECK(profiler_ == nullptr);
     profiler_ = profiler;
     IncreaseProfilingDepth();
     if (!IsActive()) Start();
@@ -638,7 +638,7 @@ class Ticker: public sampler::Sampler {
   }
 
   void ClearProfiler() {
-    profiler_ = NULL;
+    profiler_ = nullptr;
     if (IsActive()) Stop();
     DecreaseProfilingDepth();
     sampling_thread_->Join();
@@ -646,15 +646,9 @@ class Ticker: public sampler::Sampler {
 
   void SampleStack(const v8::RegisterState& state) override {
     if (!profiler_) return;
-    v8::Isolate* v8_isolate = isolate();
-    Isolate* i_isolate = reinterpret_cast<Isolate*>(v8_isolate);
-#if defined(USE_SIMULATOR)
-    if (!SimulatorHelper::FillRegisters(i_isolate,
-                                        const_cast<v8::RegisterState*>(&state)))
-      return;
-#endif
+    Isolate* isolate = reinterpret_cast<Isolate*>(this->isolate());
     TickSample sample;
-    sample.Init(i_isolate, state, TickSample::kIncludeCEntryFrame, true);
+    sample.Init(isolate, state, TickSample::kIncludeCEntryFrame, true);
     profiler_->Insert(&sample);
   }
 

src/profiler/cpu-profiler.cc

@@ -23,18 +23,11 @@ class CpuSampler : public sampler::Sampler {
       : sampler::Sampler(reinterpret_cast<v8::Isolate*>(isolate)),
         processor_(processor) {}
 
-  void SampleStack(const v8::RegisterState& state) override {
-    v8::Isolate* v8_isolate = isolate();
-    Isolate* i_isolate = reinterpret_cast<Isolate*>(v8_isolate);
-#if defined(USE_SIMULATOR)
-    v8::RegisterState regs;
-    if (!SimulatorHelper::FillRegisters(i_isolate, &regs)) return;
-#else
-    const v8::RegisterState& regs = state;
-#endif
+  void SampleStack(const v8::RegisterState& regs) override {
     TickSample* sample = processor_->StartTickSample();
-    if (sample == NULL) return;
-    sample->Init(i_isolate, regs, TickSample::kIncludeCEntryFrame, true);
+    if (sample == nullptr) return;
+    Isolate* isolate = reinterpret_cast<Isolate*>(this->isolate());
+    sample->Init(isolate, regs, TickSample::kIncludeCEntryFrame, true);
     if (is_counting_samples_ && !sample->timestamp.IsNull()) {
       if (sample->state == JS) ++js_sample_count_;
       if (sample->state == EXTERNAL) ++external_sample_count_;

src/profiler/tick-sample.cc

@@ -11,7 +11,6 @@
 #include "src/vm-state-inl.h"
 
 namespace v8 {
-
 namespace {
 
 bool IsSamePage(i::byte* ptr1, i::byte* ptr2) {
@@ -77,6 +76,73 @@ bool IsNoFrameRegion(i::Address address) {
 
 }  // namespace
 
+namespace internal {
+namespace {
+
+#if defined(USE_SIMULATOR)
+class SimulatorHelper {
+ public:
+  // Returns true if register values were successfully retrieved
+  // from the simulator, otherwise returns false.
+  static bool FillRegisters(Isolate* isolate, v8::RegisterState* state);
+};
+
+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
+
+}  // namespace
+}  // namespace internal
+
 //
 // StackTracer implementation
 //
@@ -85,35 +151,33 @@ DISABLE_ASAN void TickSample::Init(Isolate* v8_isolate,
                                    RecordCEntryFrame record_c_entry_frame,
                                    bool update_stats) {
   this->update_stats = update_stats;
-
   SampleInfo info;
-  if (GetStackSample(v8_isolate, const_cast<RegisterState&>(regs),
-                     record_c_entry_frame, reinterpret_cast<void**>(&stack[0]),
-                     kMaxFramesCount, &info)) {
-    state = info.vm_state;
-    pc = regs.pc;
-    frames_count = static_cast<unsigned>(info.frames_count);
-    has_external_callback = info.external_callback_entry != nullptr;
-    if (has_external_callback) {
-      external_callback_entry = info.external_callback_entry;
-    } else if (frames_count) {
-      // sp register may point at an arbitrary place in memory, make
-      // sure MSAN doesn't complain about it.
-      MSAN_MEMORY_IS_INITIALIZED(regs.sp, sizeof(void*));
-      // Sample potential return address value for frameless invocation of
-      // stubs (we'll figure out later, if this value makes sense).
-      tos = i::Memory::Address_at(reinterpret_cast<i::Address>(regs.sp));
-    } else {
-      tos = nullptr;
-    }
-  } else {
+  if (!GetStackSample(v8_isolate, regs, record_c_entry_frame, stack,
+                      kMaxFramesCount, &info)) {
     // It is executing JS but failed to collect a stack trace.
     // Mark the sample as spoiled.
     pc = nullptr;
+    return;
+  }
+  state = info.vm_state;
+  pc = regs.pc;
+  frames_count = static_cast<unsigned>(info.frames_count);
+  has_external_callback = info.external_callback_entry != nullptr;
+  if (has_external_callback) {
+    external_callback_entry = info.external_callback_entry;
+  } else if (frames_count) {
+    // sp register may point at an arbitrary place in memory, make
+    // sure MSAN doesn't complain about it.
+    MSAN_MEMORY_IS_INITIALIZED(regs.sp, sizeof(void*));
+    // Sample potential return address value for frameless invocation of
+    // stubs (we'll figure out later, if this value makes sense).
+    tos = i::Memory::Address_at(reinterpret_cast<i::Address>(regs.sp));
+  } else {
+    tos = nullptr;
   }
 }
 
-bool TickSample::GetStackSample(Isolate* v8_isolate, const RegisterState& regs,
+bool TickSample::GetStackSample(Isolate* v8_isolate, const RegisterState& state,
                                 RecordCEntryFrame record_c_entry_frame,
                                 void** frames, size_t frames_limit,
                                 v8::SampleInfo* sample_info) {
@@ -125,10 +189,17 @@ bool TickSample::GetStackSample(Isolate* v8_isolate, const RegisterState& regs,
 
   i::Address js_entry_sp = isolate->js_entry_sp();
   if (js_entry_sp == nullptr) return true;  // Not executing JS now.
+
+#if defined(USE_SIMULATOR)
+  v8::RegisterState regs;
+  if (!i::SimulatorHelper::FillRegisters(isolate, &regs)) return false;
+#else
+  const v8::RegisterState& regs = state;
+#endif
   DCHECK(regs.sp);
 
   if (regs.pc && IsNoFrameRegion(static_cast<i::Address>(regs.pc))) {
-    // Can't collect stack.
+    // The frame is not setup, so it'd be hard to iterate the stack. Bailout.
     return false;
   }
 
@@ -183,59 +254,5 @@ void TickSample::Init(Isolate* isolate, const v8::RegisterState& state,
   timestamp = base::TimeTicks::HighResolutionNow();
 }
 
-#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
-
 }  // namespace internal
 }  // namespace v8

src/profiler/tick-sample.h

@@ -15,21 +15,11 @@ namespace internal {
 class Isolate;
 
 struct TickSample : public v8::TickSample {
-  TickSample() : v8::TickSample() {}
   void Init(Isolate* isolate, const v8::RegisterState& state,
             RecordCEntryFrame record_c_entry_frame, bool update_stats);
   base::TimeTicks timestamp;
 };
 
-#if defined(USE_SIMULATOR)
-class SimulatorHelper {
- public:
-  // Returns true if register values were successfully retrieved
-  // from the simulator, otherwise returns false.
-  static bool FillRegisters(Isolate* isolate, v8::RegisterState* state);
-};
-#endif  // USE_SIMULATOR
-
 }  // namespace internal
 }  // namespace v8
 

test/cctest/libsampler/test-sampler.cc

@@ -41,10 +41,9 @@ class TestSampler : public Sampler {
   explicit TestSampler(Isolate* isolate) : Sampler(isolate) {}
 
   void SampleStack(const v8::RegisterState& regs) override {
-    void* frames[Sampler::kMaxFramesCount];
+    void* frames[kMaxFramesCount];
     SampleInfo sample_info;
-    isolate()->GetStackSample(regs, reinterpret_cast<void**>(frames),
-                              Sampler::kMaxFramesCount, &sample_info);
+    isolate()->GetStackSample(regs, frames, kMaxFramesCount, &sample_info);
     if (is_counting_samples_) {
       if (sample_info.vm_state == JS) ++js_sample_count_;
       if (sample_info.vm_state == EXTERNAL) ++external_sample_count_;