[heap] Do not invoke GC to make heap iterable.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index afdc7bb4cd397d69625ecdca09c295a668e0a6ae..5dab9451677bf2c340bb075aadbbd2c6a541dc13 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -893,7 +893,8 @@ void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
     isolate()->optimizing_compile_dispatcher()->Flush();
   }
   isolate()->ClearSerializerData();
-  set_current_gc_flags(kMakeHeapIterableMask | kReduceMemoryFootprintMask);
+  set_current_gc_flags(kAbortIncrementalMarkingMask |
+                       kReduceMemoryFootprintMask);
   isolate_->compilation_cache()->Clear();
   const int kMaxNumberOfAttempts = 7;
   const int kMinNumberOfAttempts = 2;
@@ -4032,22 +4033,10 @@ AllocationResult Heap::AllocateStruct(InstanceType type) {
 }
 
 
-bool Heap::IsHeapIterable() {
-  // TODO(hpayer): This function is not correct. Allocation folding in old
-  // space breaks the iterability.
-  return new_space_top_after_last_gc_ == new_space()->top();
-}
-
-
 void Heap::MakeHeapIterable() {
-  DCHECK(AllowHeapAllocation::IsAllowed());
-  if (!IsHeapIterable()) {
-    CollectAllGarbage(kMakeHeapIterableMask, "Heap::MakeHeapIterable");
-  }
   if (mark_compact_collector()->sweeping_in_progress()) {
     mark_compact_collector()->EnsureSweepingCompleted();
   }
-  DCHECK(IsHeapIterable());
 }
 
 
@@ -4592,10 +4581,7 @@ void Heap::Verify() {
   CHECK(HasBeenSetUp());
   HandleScope scope(isolate());
 
-  if (mark_compact_collector()->sweeping_in_progress()) {
-    // We have to wait here for the sweeper threads to have an iterable heap.
-    mark_compact_collector()->EnsureSweepingCompleted();
-  }
+  MakeHeapIterable();
 
   VerifyPointersVisitor visitor;
   IterateRoots(&visitor, VISIT_ONLY_STRONG);