Move *BSD and Solaris Sampler implementations into sampler.cc

src/sampler.h

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_SAMPLER_H_
+#define V8_SAMPLER_H_
+
+#include "atomicops.h"
+#include "v8globals.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+
+// ----------------------------------------------------------------------------
+// Sampler
+//
+// A sampler periodically samples the state of the VM and optionally
+// (if used for profiling) the program counter and stack pointer for
+// the thread that created it.
+
+// TickSample captures the information collected for each sample.
+class TickSample {
+ public:

[Sven Panne, 2013/04/15 07:08:40]

Style nit: Use a struct instead of class+public, it makes it immediately
crystal-clear that this is a POD (with a convenience constructor).

[yurys, 2013/04/15 11:37:55]

Done.

+  TickSample()
+      : state(OTHER),
+        pc(NULL),
+        sp(NULL),
+        fp(NULL),
+        external_callback(NULL),
+        frames_count(0) {}
+  StateTag state;  // The state of the VM.
+  Address pc;      // Instruction pointer.
+  Address sp;      // Stack pointer.
+  Address fp;      // Frame pointer.
+  Address external_callback;
+  static const int kMaxFramesCount = 64;
+  Address stack[kMaxFramesCount];  // Call stack.
+  int frames_count : 8;  // Number of captured frames.
+};
+
+class Sampler {
+ public:
+  // Initializes the Sampler support. Called once at VM startup.
+  static void SetUp();
+  static void TearDown();
+
+  // Initialize sampler.
+  Sampler(Isolate* isolate, int interval);
+  virtual ~Sampler();
+
+  int interval() const { return interval_; }
+
+  // Performs stack sampling.
+  void SampleStack(TickSample* sample);
+
+  // This method is called for each sampling period with the current
+  // program counter.
+  virtual void Tick(TickSample* sample) = 0;
+
+  // Start and stop sampler.
+  void Start();
+  void Stop();
+
+  // Is the sampler used for profiling?
+  bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
+  void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); }
+  void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); }
+
+  // Whether the sampler is running (that is, consumes resources).
+  bool IsActive() const { return NoBarrier_Load(&active_); }
+
+  Isolate* isolate() { return isolate_; }

[Sven Panne, 2013/04/15 07:08:40]

Add "const". Move it just above interval(), this makes it a bit clearer that
those 2 functions just return the constructor arguments right above them.

[yurys, 2013/04/15 11:37:55]

Done.

+
+  // Used in tests to make sure that stack sampling is performed.
+  int samples_taken() const { return samples_taken_; }
+  void ResetSamplesTaken() { samples_taken_ = 0; }
+
+  class PlatformData;
+  PlatformData* data() { return data_; }
+
+  PlatformData* platform_data() { return data_; }

[Sven Panne, 2013/04/15 07:08:40]

Why do we need 2 accessors? "const" would be nice, too.

[yurys, 2013/04/15 11:37:55]

Removed data() accessor, it wasn't used. Added const to platform_data accessor.

+
+ private:
+  void SetActive(bool value) { NoBarrier_Store(&active_, value); }
+
+  Isolate* isolate_;
+  const int interval_;
+  Atomic32 profiling_;
+  Atomic32 active_;
+  PlatformData* data_;  // Platform specific data.
+  int samples_taken_;  // Counts stack samples taken.
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_SAMPLER_H_