Initial GetSample implementation.

src/profile-generator.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/profile-generator-inl.h"
 
 #include "src/compiler.h"
 #include "src/debug.h"
@@ skipping 610 matching lines @@
           // frame. In the latter case we know the caller for sure but in the
           // former case we don't so we simply replace the frame with
           // 'unresolved' entry.
           if (sample.top_frame_type == StackFrame::JAVA_SCRIPT) {
             *entry++ = unresolved_entry_;
           }
         }
       }
     }
 
-    for (const Address* stack_pos = sample.stack,
+    for (const Address* stack_pos = reinterpret_cast<const Address*>(sample.stack),

[Sven Panne, 2014/09/02 08:15:02]

static_cast again, the const seems to be unnecessary here.

[gholap, 2014/09/02 08:56:08]

Hmm... that should work for individual pointers, right? and not arrays of
pointers?
(won't compile unless reinterpret_cast and const both are present...)

[Sven Panne, 2014/09/02 11:15:36]

Done correctly, it *would* work, but actually there is a far easier way than
this unreadable pointer fiddling:

  for (unsigned i = 0; i < sample.frames_count; ++i) {
    *entry++ = code_map_.FindEntry(static_cast<Address>(sample.stack[i]));
  }

Looking at the use sites, you might even consider replacing the old-skool
array+size interface of Sample by an iterator interface with begin() and end(),
so one could write (in C++11, available soon):

  for (auto slot: sample) {
    *entry++ = code_map_.FindEntry(static_cast<Address>(slot));
  }

[gholap, 2014/09/02 14:43:11]

Done. I know where I went wrong! I took my working thumb-rule to be edit/touch
as few lines of code as possible :P That way, I didn't even consider what is
going on inside the for loop! I'll make efforts to avoid such thing
henceforth...

            *stack_end = stack_pos + sample.frames_count;
          stack_pos != stack_end;
          ++stack_pos) {
       *entry++ = code_map_.FindEntry(*stack_pos);
     }
   }
 
   if (FLAG_prof_browser_mode) {
     bool no_symbolized_entries = true;
     for (CodeEntry** e = entries.start(); e != entry; ++e) {
@@ skipping 24 matching lines @@
     case OTHER:
     case EXTERNAL:
       return program_entry_;
     case IDLE:
       return idle_entry_;
     default: return NULL;
   }
 }
 
 } }  // namespace v8::internal