Reland concurrent sweeping of code space.

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/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 491 matching lines @@
     case LO_SPACE:
       return "large_object_space";
     default:
       UNREACHABLE();
   }
   return nullptr;
 }
 
 
 void Heap::ClearAllICsByKind(Code::Kind kind) {
+  // TODO(mvstanton): Do not iterate the heap.
   HeapObjectIterator it(code_space());
 
   for (Object* object = it.Next(); object != NULL; object = it.Next()) {
     Code* code = Code::cast(object);
     Code::Kind current_kind = code->kind();
     if (current_kind == Code::FUNCTION ||
         current_kind == Code::OPTIMIZED_FUNCTION) {
       code->ClearInlineCaches(kind);
     }
   }
@@ skipping 4721 matching lines @@
 
   new_space_.Verify();
 
   old_space_->Verify(&visitor);
   map_space_->Verify(&visitor);
 
   VerifyPointersVisitor no_dirty_regions_visitor;
   code_space_->Verify(&no_dirty_regions_visitor);
 
   lo_space_->Verify();
+
+  mark_compact_collector_.VerifyWeakEmbeddedObjectsInCode();
+  if (FLAG_omit_map_checks_for_leaf_maps) {
+    mark_compact_collector_.VerifyOmittedMapChecks();
+  }
 }
 #endif
 
 
 void Heap::ZapFromSpace() {
   if (!new_space_.IsFromSpaceCommitted()) return;
   NewSpacePageIterator it(new_space_.FromSpaceStart(),
                           new_space_.FromSpaceEnd());
   while (it.has_next()) {
     NewSpacePage* page = it.next();
@@ skipping 1726 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