Introduce SharedFunctionInfo::Iterator and Script::Iterator.

src/heap/heap.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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 697 matching lines @@
   // Remember the last top pointer so that we can later find out
   // whether we allocated in new space since the last GC.
   new_space_top_after_last_gc_ = new_space()->top();
   last_gc_time_ = MonotonicallyIncreasingTimeInMs();
 
   ReduceNewSpaceSize();
 }
 
 
 void Heap::PreprocessStackTraces() {
-  if (!weak_stack_trace_list()->IsWeakFixedArray()) return;
-  WeakFixedArray* array = WeakFixedArray::cast(weak_stack_trace_list());
-  int length = array->Length();
-  for (int i = 0; i < length; i++) {
-    if (array->IsEmptySlot(i)) continue;
-    FixedArray* elements = FixedArray::cast(array->Get(i));
+  WeakFixedArray::Iterator iterator(weak_stack_trace_list());
+  FixedArray* elements;
+  while ((elements = iterator.Next<FixedArray>())) {
     for (int j = 1; j < elements->length(); j += 4) {
       Object* maybe_code = elements->get(j + 2);
       // If GC happens while adding a stack trace to the weak fixed array,
       // which has been copied into a larger backing store, we may run into
       // a stack trace that has already been preprocessed. Guard against this.
       if (!maybe_code->IsCode()) break;
       Code* code = Code::cast(maybe_code);
       int offset = Smi::cast(elements->get(j + 3))->value();
       Address pc = code->address() + offset;
       int pos = code->SourcePosition(pc);
@@ skipping 6141 matching lines @@
     *object_type = "CODE_TYPE";                                                \
     *object_sub_type = "CODE_AGE/" #name;                                      \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 }  // namespace internal
 }  // namespace v8