CPU profiler: increase the max number of captured frames.

src/sampler.h

 // 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.
 
 #ifndef V8_SAMPLER_H_
 #define V8_SAMPLER_H_
 
 #include "src/base/atomicops.h"
 #include "src/frames.h"
 #include "src/globals.h"
@@ skipping 26 matching lines @@
         frames_count(0),
         has_external_callback(false),
         top_frame_type(StackFrame::NONE) {}
   void Init(Isolate* isolate, const RegisterState& state);
   StateTag state;  // The state of the VM.
   Address pc;      // Instruction pointer.
   union {
     Address tos;   // Top stack value (*sp).
     Address external_callback;
   };
-  static const int kMaxFramesCount = 64;
+  static const unsigned kMaxFramesCountLog2 = 8;
+  static const unsigned kMaxFramesCount = (1 << kMaxFramesCountLog2) - 1;
   Address stack[kMaxFramesCount];  // Call stack.
   TimeTicks timestamp;
-  int frames_count : 8;  // Number of captured frames.
+  unsigned frames_count : kMaxFramesCountLog2;  // Number of captured frames.
   bool has_external_callback : 1;
   StackFrame::Type top_frame_type : 4;
 };
 
 class Sampler {
  public:
   // Initializes the Sampler support. Called once at VM startup.
   static void SetUp();
   static void TearDown();
 
@@ skipping 58 matching lines @@
   bool is_counting_samples_;
   // Counts stack samples taken in JS VM state.
   unsigned js_and_external_sample_count_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SAMPLER_H_