[Interpreter] Add support for cpu profiler logging.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 2d74dc4a63a9b89d4542eb1ec8a8ab24662ddd4d..94c6679aea072222c899baf35d5300e36a023db5 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -614,6 +614,19 @@ class Isolate {
     return &thread_local_top_.js_entry_sp_;
   }
 
+  inline Address interpreter_entry_trampoline_start() {
+    return interpreter_entry_trampoline_start_;

[Yang, 2016/02/25 11:50:43]

Do we really need this cache? This requires the code object for the interpreter
entry trampoline to never move. We could also just get
builtins()->InterpreterEntryTrampoline()->instruction_start().

[rmcilroy, 2016/02/25 11:55:11]

This is not a cache, it is required for safty in the sampling thread. Originally
I was using builtins()->InterpreterEntryTrampoline(), but we can't do that in
StackFrame::ComputeType for SafeStackIterator (i.e., when
!iterator->can_access_heap_objects_) since it requires dereferencing of heap
pointers and handles which is not safe at any arbitrary point that the sampler
might interrupt the main thread. The particular situation I've seen is where
DisallowHandleDereference is on the stack when the profiler interrupts the main
thread, which causes the sampler thread to crash when dereferencing
builtins()->InterpreterEntryTrampoline()

[rmcilroy, 2016/02/25 15:06:54]

Done.

+  }
+  inline Address interpreter_entry_trampoline_end() {
+    return interpreter_entry_trampoline_end_;
+  }
+  inline Address interpreter_bytecode_dispatch_start() {
+    return interpreter_bytecode_dispatch_start_;
+  }
+  inline Address interpreter_bytecode_dispatch_end() {
+    return interpreter_bytecode_dispatch_end_;
+  }
+
   // Returns the global object of the current context. It could be
   // a builtin object, or a JS global object.
   inline Handle<JSGlobalObject> global_object();
@@ -1315,6 +1328,13 @@ class Isolate {
   Address virtual_handler_register_;
   Address virtual_slot_register_;
 
+  // Addresses used in frames.cc to determine if a frame is an interpreter
+  // frame without looking at heap objects.
+  Address interpreter_entry_trampoline_start_;
+  Address interpreter_entry_trampoline_end_;
+  Address interpreter_bytecode_dispatch_start_;
+  Address interpreter_bytecode_dispatch_end_;
+
   int next_optimization_id_;
 
   // Counts javascript calls from the API. Wraps around on overflow.