Move SimulatorHelper into V8 out of profiler clients.

src/profiler/tick-sample.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/profiler/tick-sample.h"
 
 #include "include/v8-profiler.h"
 #include "src/frames-inl.h"
 #include "src/msan.h"
 #include "src/simulator.h"
 #include "src/vm-state-inl.h"
 
 namespace v8 {
-
 namespace {
 
 bool IsSamePage(i::byte* ptr1, i::byte* ptr2) {
   const uint32_t kPageSize = 4096;
   uintptr_t mask = ~static_cast<uintptr_t>(kPageSize - 1);
   return (reinterpret_cast<uintptr_t>(ptr1) & mask) ==
          (reinterpret_cast<uintptr_t>(ptr2) & mask);
 }
 
 // Check if the code at specified address could potentially be a
@@ skipping 45 matching lines @@
         if (!memcmp(pc, pattern->bytes + offset, pattern->bytes_count - offset))
           return true;
       }
     }
   }
   return false;
 }
 
 }  // 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
 //
 DISABLE_ASAN void TickSample::Init(Isolate* v8_isolate,
-                                   const RegisterState& regs,
+                                   const RegisterState& reg_state,

[alph, 2016/08/09 19:03:41]

state

[lpy, 2016/08/10 05:50:03]

TickSample already has a different type of data member called state.

                                    RecordCEntryFrame record_c_entry_frame,
-                                   bool update_stats) {
+                                   bool update_stats, bool update_state) {
   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 {
+  RegisterState regs = reg_state;
+  if (!GetStackSample(v8_isolate, &regs, record_c_entry_frame, stack,
+                      kMaxFramesCount, &info, update_state)) {
     // 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, RegisterState* regs,
                                 RecordCEntryFrame record_c_entry_frame,
                                 void** frames, size_t frames_limit,
-                                v8::SampleInfo* sample_info) {
+                                v8::SampleInfo* sample_info,
+                                bool update_state) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(v8_isolate);
   sample_info->frames_count = 0;
   sample_info->vm_state = isolate->current_vm_state();
   sample_info->external_callback_entry = nullptr;
   if (sample_info->vm_state == GC) return true;
 
   i::Address js_entry_sp = isolate->js_entry_sp();
   if (js_entry_sp == nullptr) return true;  // Not executing JS now.
-  DCHECK(regs.sp);
 
-  if (regs.pc && IsNoFrameRegion(static_cast<i::Address>(regs.pc))) {
-    // Can't collect stack.
+#if defined(USE_SIMULATOR)
+  if (update_state) {

[alph, 2016/08/09 19:03:41]

update_state is never referenced when not under simulator. You may get some
compiler warning. USE(update_state) should help.

[lpy, 2016/08/10 05:50:03]

Done.

+    if (!i::SimulatorHelper::FillRegisters(isolate, regs)) return false;
+  }
+#endif
+  DCHECK(regs->sp);
+
+  if (regs->pc && IsNoFrameRegion(static_cast<i::Address>(regs->pc))) {
+    // The frame is not setup, so it'd be hard to iterate the stack. Bailout.
     return false;
   }
 
   i::ExternalCallbackScope* scope = isolate->external_callback_scope();
   i::Address handler = i::Isolate::handler(isolate->thread_local_top());
   // If there is a handler on top of the external callback scope then
   // we have already entrered JavaScript again and the external callback
   // is not the top function.
   if (scope && scope->scope_address() < handler) {
     sample_info->external_callback_entry =
         *scope->callback_entrypoint_address();
   }
 
-  i::SafeStackFrameIterator it(isolate, reinterpret_cast<i::Address>(regs.fp),
-                               reinterpret_cast<i::Address>(regs.sp),
+  i::SafeStackFrameIterator it(isolate, reinterpret_cast<i::Address>(regs->fp),
+                               reinterpret_cast<i::Address>(regs->sp),
                                js_entry_sp);
 
   // If at this point iterator does not see any frames,
   // is usually means something is wrong with the FP,
   // e.g. it is used as a general purpose register in the function.
   // Bailout.
   if (it.done()) return false;
 
   size_t i = 0;
   if (record_c_entry_frame == kIncludeCEntryFrame &&
@@ skipping 16 matching lines @@
     frames[i++] = bytecode_array + i::BytecodeArray::kHeaderSize +
                   frame->GetBytecodeOffset();
   }
   sample_info->frames_count = i;
   return true;
 }
 
 namespace internal {
 
 void TickSample::Init(Isolate* isolate, const v8::RegisterState& state,
-                      RecordCEntryFrame record_c_entry_frame,
-                      bool update_stats) {
+                      RecordCEntryFrame record_c_entry_frame, bool update_stats,
+                      bool update_state) {
   v8::TickSample::Init(reinterpret_cast<v8::Isolate*>(isolate), state,
-                       record_c_entry_frame, update_stats);
+                       record_c_entry_frame, update_stats, update_state);
   if (pc == nullptr) return;
   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