Fix Heap::IsHeapIterable.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index a63fd65d4bc6b2298a08bcdad7a62e160867ede8..30735f1f97902f0df742a35a176b1a875592071f 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -13126,14 +13126,6 @@ RUNTIME_FUNCTION(Runtime_DebugReferencedBy) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 3);
 
-  // First perform a full GC in order to avoid references from dead objects.
-  Heap* heap = isolate->heap();
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask, "%DebugReferencedBy");
-  // The heap iterator reserves the right to do a GC to make the heap iterable.
-  // Due to the GC above we know it won't need to do that, but it seems cleaner
-  // to get the heap iterator constructed before we start having unprotected
-  // Object* locals that are not protected by handles.
-
   // Check parameters.
   CONVERT_ARG_HANDLE_CHECKED(JSObject, target, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, instance_filter, 1);
@@ -13151,6 +13143,10 @@ RUNTIME_FUNCTION(Runtime_DebugReferencedBy) {
 
   // Get the number of referencing objects.
   int count;
+  // First perform a full GC in order to avoid dead objects and to make the heap
+  // iterable.
+  Heap* heap = isolate->heap();
+  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask, "%DebugConstructedBy");
   HeapIterator heap_iterator(heap);
   count = DebugReferencedBy(&heap_iterator,
                             *target, *instance_filter, max_references,
@@ -13160,8 +13156,7 @@ RUNTIME_FUNCTION(Runtime_DebugReferencedBy) {
   Handle<FixedArray> instances = isolate->factory()->NewFixedArray(count);
 
   // Fill the referencing objects.
-  // AllocateFixedArray above does not make the heap non-iterable.
-  ASSERT(heap->IsHeapIterable());
+  heap->MakeHeapIterable();
   HeapIterator heap_iterator2(heap);
   count = DebugReferencedBy(&heap_iterator2,
                             *target, *instance_filter, max_references,
@@ -13216,9 +13211,6 @@ RUNTIME_FUNCTION(Runtime_DebugConstructedBy) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
-  // First perform a full GC in order to avoid dead objects.
-  Heap* heap = isolate->heap();
-  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask, "%DebugConstructedBy");
 
   // Check parameters.
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, constructor, 0);
@@ -13227,6 +13219,10 @@ RUNTIME_FUNCTION(Runtime_DebugConstructedBy) {
 
   // Get the number of referencing objects.
   int count;
+  // First perform a full GC in order to avoid dead objects and to make the heap
+  // iterable.
+  Heap* heap = isolate->heap();
+  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask, "%DebugConstructedBy");
   HeapIterator heap_iterator(heap);
   count = DebugConstructedBy(&heap_iterator,
                              *constructor,
@@ -13237,8 +13233,8 @@ RUNTIME_FUNCTION(Runtime_DebugConstructedBy) {
   // Allocate an array to hold the result.
   Handle<FixedArray> instances = isolate->factory()->NewFixedArray(count);
 
-  ASSERT(heap->IsHeapIterable());
   // Fill the referencing objects.
+  heap->MakeHeapIterable();
   HeapIterator heap_iterator2(heap);
   count = DebugConstructedBy(&heap_iterator2,
                              *constructor,
@@ -13376,7 +13372,7 @@ RUNTIME_FUNCTION(Runtime_LiveEditFindSharedFunctionInfosForScript) {
   int number;
   Heap* heap = isolate->heap();
   {
-    heap->EnsureHeapIsIterable();
+    heap->MakeHeapIterable();
     DisallowHeapAllocation no_allocation;
     HeapIterator heap_iterator(heap);
     Script* scr = *script;
@@ -13385,7 +13381,7 @@ RUNTIME_FUNCTION(Runtime_LiveEditFindSharedFunctionInfosForScript) {
   }
   if (number > kBufferSize) {
     array = isolate->factory()->NewFixedArray(number);
-    heap->EnsureHeapIsIterable();
+    heap->MakeHeapIterable();
     DisallowHeapAllocation no_allocation;
     HeapIterator heap_iterator(heap);
     Script* scr = *script;
@@ -14469,7 +14465,7 @@ static Handle<Object> Runtime_GetScriptFromScriptName(
   Handle<Script> script;
   Factory* factory = script_name->GetIsolate()->factory();
   Heap* heap = script_name->GetHeap();
-  heap->EnsureHeapIsIterable();
+  heap->MakeHeapIterable();
   DisallowHeapAllocation no_allocation_during_heap_iteration;
   HeapIterator iterator(heap);
   HeapObject* obj = NULL;