Make Isolate::GetStackSample API support simulator

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 47fc1ce1b2f62ba22dd739aeba225c14da1b9230..15e5b6934af400b996bc4d8db528194693042edf 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -7527,6 +7527,71 @@ void Isolate::GetStackSample(const RegisterState& state, void** frames,
 }
 
 
+void Isolate::GetStackSample(RegisterState* state, void** frames,

[alph, 2016/04/27 22:29:20]

v8 usually do not put that much implementation specific code into api.cc
Also copying code is a bad practice, can you please move it into
i::TickSample::GetStackSample and make the current sampler use it.

+                             size_t frames_limit, SampleInfo* sample_info) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+#if defined(USE_SIMULATOR)
+  i::Simulator *simulator = isolate->thread_local_top()->simulator_;
+  if (simulator != NULL) {
+#if V8_TARGET_ARCH_ARM
+    if (!simulator->has_bad_pc()) {
+      state->pc = reinterpret_cast<void*>(simulator->get_pc());
+    }
+    state->sp = reinterpret_cast<void*>(simulator->get_register(
+        i::Simulator::sp));
+    state->fp = reinterpret_cast<void*>(simulator->get_register(
+        i::Simulator::r11));
+#elif V8_TARGET_ARCH_ARM64
+    if (simulator->sp() == 0 || simulator->fp() == 0) {
+      // It's 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 a 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;
+    }
+    state->pc = reinterpret_cast<void*>(simulator->pc());
+    state->sp = reinterpret_cast<void*>(simulator->sp());
+    state->fp = reinterpret_cast<void*>(simulator->fp());
+#elif V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64
+    if (!simulator->has_bad_pc()) {
+      state->pc = reinterpret_cast<void*>(simulator->get_pc());
+    }
+    state->sp = reinterpret_cast<void*>(simulator->get_register(
+        i::Simulator::sp));
+    state->fp = reinterpret_cast<void*>(simulator->get_register(
+        i::Simulator::fp));
+#elif V8_TARGET_ARCH_PPC
+    if (!simulator->has_bad_pc()) {
+      state->pc = reinterpret_cast<void*>(simulator->get_pc());
+    }
+    state->sp =
+        reinterpret_cast<void*>(simulator->get_register(i::Simulator::sp));
+    state->fp =
+        reinterpret_cast<void*>(simulator->get_register(i::Simulator::fp));
+#elif V8_TARGET_ARCH_S390
+    if (!simulator->has_bad_pc()) {
+      state->pc = reinterpret_cast<void*>(simulator->get_pc());
+    }
+    state->sp =
+        reinterpret_cast<void*>(simulator->get_register(i::Simulator::sp));
+    state->fp =
+        reinterpret_cast<void*>(simulator->get_register(i::Simulator::fp));
+#endif
+  }
+#endif  // USE_SIMULATOR
+  i::TickSample::GetStackSample(isolate, *state,
+                                i::TickSample::kSkipCEntryFrame,
+                                frames, frames_limit, sample_info);
+}
+
+
 void Isolate::SetEventLogger(LogEventCallback that) {
   // Do not overwrite the event logger if we want to log explicitly.
   if (i::FLAG_log_internal_timer_events) return;