Attempt no. 3 to fix Heap::IsHeapIterable and HeapIterator

src/debug.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 "v8.h"
 
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "code-stubs.h"
@@ skipping 2035 matching lines @@
     // We could perhaps avoid this list and instead re-use the GC metadata
     // links.
     List<Handle<JSFunction> > generator_functions;
 
     {
       // We are going to iterate heap to find all functions without
       // debug break slots.
       Heap* heap = isolate_->heap();
       heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                               "preparing for breakpoints");
+      HeapIterator iterator(heap);
 
       // Ensure no GC in this scope as we are going to use gc_metadata
       // field in the Code object to mark active functions.
       DisallowHeapAllocation no_allocation;
 
       Object* active_code_marker = heap->the_hole_value();
 
       CollectActiveFunctionsFromThread(isolate_,
                                        isolate_->thread_local_top(),
                                        &active_functions,
                                        active_code_marker);
       ActiveFunctionsCollector active_functions_collector(&active_functions,
                                                           active_code_marker);
       isolate_->thread_manager()->IterateArchivedThreads(
           &active_functions_collector);
 
       // Scan the heap for all non-optimized functions which have no
       // debug break slots and are not active or inlined into an active
       // function and mark them for lazy compilation.
-      HeapIterator iterator(heap);
       HeapObject* obj = NULL;
       while (((obj = iterator.next()) != NULL)) {
         if (obj->IsJSFunction()) {
           JSFunction* function = JSFunction::cast(obj);
           SharedFunctionInfo* shared = function->shared();
 
           if (!shared->allows_lazy_compilation()) continue;
           if (!shared->script()->IsScript()) continue;
           if (function->IsBuiltin()) continue;
           if (shared->code()->gc_metadata() == active_code_marker) continue;
@@ skipping 104 matching lines @@
   // NOTE: The below fix-point iteration depends on all functions that cannot be
   // compiled lazily without a context to not be compiled at all. Compilation
   // will be triggered at points where we do not need a context.
   bool done = false;
   // The current candidate for the source position:
   int target_start_position = RelocInfo::kNoPosition;
   Handle<JSFunction> target_function;
   Handle<SharedFunctionInfo> target;
   Heap* heap = isolate_->heap();
   while (!done) {
-    { // Extra scope for iterator and no-allocation.
-      heap->EnsureHeapIsIterable();
-      DisallowHeapAllocation no_alloc_during_heap_iteration;
+    { // Extra scope for iterator.
       HeapIterator iterator(heap);
       for (HeapObject* obj = iterator.next();
            obj != NULL; obj = iterator.next()) {
         bool found_next_candidate = false;
         Handle<JSFunction> function;
         Handle<SharedFunctionInfo> shared;
         if (obj->IsJSFunction()) {
           function = Handle<JSFunction>(JSFunction::cast(obj));
           shared = Handle<SharedFunctionInfo>(function->shared());
           ASSERT(shared->allows_lazy_compilation() || shared->is_compiled());
@@ skipping 309 matching lines @@
 
 void Debug::CreateScriptCache() {
   Heap* heap = isolate_->heap();
   HandleScope scope(isolate_);
 
   // Perform two GCs to get rid of all unreferenced scripts. The first GC gets
   // rid of all the cached script wrappers and the second gets rid of the
   // scripts which are no longer referenced.  The second also sweeps precisely,
   // which saves us doing yet another GC to make the heap iterable.
   heap->CollectAllGarbage(Heap::kNoGCFlags, "Debug::CreateScriptCache");
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "Debug::CreateScriptCache");
 
   ASSERT(script_cache_ == NULL);
   script_cache_ = new ScriptCache(isolate_);
 
   // Scan heap for Script objects.
   int count = 0;
   HeapIterator iterator(heap);
-  DisallowHeapAllocation no_allocation;
 
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (obj->IsScript() && Script::cast(obj)->HasValidSource()) {
       script_cache_->Add(Handle<Script>(Script::cast(obj)));
       count++;
     }
   }
 }
 
 
@@ skipping 1004 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   LockGuard<Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 } }  // namespace v8::internal