Initial implementation of GetStackSample sampling profiler API.

include/v8.h

 // Copyright 2012 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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 1397 matching lines @@
   bool IsEval() const;
 
   /**
    * Returns whether or not the associated function is called as a
    * constructor via "new".
    */
   bool IsConstructor() const;
 };
 
 
+// A StateTag represents a possible state of the VM.
+enum StateTag { JS, GC, COMPILER, OTHER, EXTERNAL, IDLE };
+
+
+// A RegisterState represents the current state of registers used
+// by the sampling profiler API.
+struct RegisterState {
+  RegisterState() : pc(NULL), sp(NULL), fp(NULL) {}
+  void* pc;  // Instruction pointer.
+  void* sp;  // Stack pointer.
+  void* fp;  // Frame pointer.
+};
+
+
+// The output structure filled up by GetStackSample API function.
+struct SampleInfo {
+  size_t frames_count;
+  StateTag vm_state;
+};
+
+
 /**
  * A JSON Parser.
  */
 class V8_EXPORT JSON {
  public:
   /**
    * Tries to parse the string |json_string| and returns it as value if
    * successful.
    *
    * \param json_string The string to parse.
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    * are in the range of 0 - GetNumberOfDataSlots() - 1.
    */
   V8_INLINE static uint32_t GetNumberOfDataSlots();
 
   /**
    * Get statistics about the heap memory usage.
    */
   void GetHeapStatistics(HeapStatistics* heap_statistics);
 
   /**
+   * Get a call stack sample from the isolate.
+   * \param state Execution state.
+   * \param frames Caller allocated buffer to store stack frames.
+   * \param frames_limit Maximum number of frames to capture. The buffer must
+   *                     be large enough to hold the number of frames.
+   * \param sample_info The sample info is filled up by the function
+   *                    provides number of actual captured stack frames and
+   *                    the current VM state.
+   * \note GetStackSample should only be called when the JS thread is paused or
+   *       interrupted. Otherwise the behavior is undefined.
+   */
+  void GetStackSample(const RegisterState& state, void** frames,
+                      size_t frames_limit, SampleInfo* sample_info);
+
+  /**
    * Adjusts the amount of registered external memory. Used to give V8 an
    * indication of the amount of externally allocated memory that is kept alive
    * by JavaScript objects. V8 uses this to decide when to perform global
    * garbage collections. Registering externally allocated memory will trigger
    * global garbage collections more often than it would otherwise in an attempt
    * to garbage collect the JavaScript objects that keep the externally
    * allocated memory alive.
    *
    * \param change_in_bytes the change in externally allocated memory that is
    *   kept alive by JavaScript objects.
@@ skipping 2388 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_