Tweaks to the code serializer.

src/heap/heap.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 
 #include "src/allocation.h"
@@ skipping 180 matching lines @@
   V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
   V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset)       \
   V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset)             \
   V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)
 
 #define ROOT_LIST(V)  \
   STRONG_ROOT_LIST(V) \
   SMI_ROOT_LIST(V)    \
   V(StringTable, string_table, StringTable)
 
-// Heap roots that are known to be immortal immovable, for which we can safely
-// skip write barriers.
-#define IMMORTAL_IMMOVABLE_ROOT_LIST(V) \
-  V(byte_array_map)                     \
-  V(free_space_map)                     \
-  V(one_pointer_filler_map)             \
-  V(two_pointer_filler_map)             \
-  V(undefined_value)                    \
-  V(the_hole_value)                     \
-  V(null_value)                         \
-  V(true_value)                         \
-  V(false_value)                        \
-  V(uninitialized_value)                \
-  V(cell_map)                           \
-  V(global_property_cell_map)           \
-  V(shared_function_info_map)           \
-  V(meta_map)                           \
-  V(heap_number_map)                    \
-  V(mutable_heap_number_map)            \
-  V(native_context_map)                 \
-  V(fixed_array_map)                    \
-  V(code_map)                           \
-  V(scope_info_map)                     \
-  V(fixed_cow_array_map)                \
-  V(fixed_double_array_map)             \
-  V(constant_pool_array_map)            \
-  V(weak_cell_map)                      \
-  V(no_interceptor_result_sentinel)     \
-  V(hash_table_map)                     \
-  V(ordered_hash_table_map)             \
-  V(empty_fixed_array)                  \
-  V(empty_byte_array)                   \
-  V(empty_descriptor_array)             \
-  V(empty_constant_pool_array)          \
-  V(arguments_marker)                   \
-  V(symbol_map)                         \
-  V(sloppy_arguments_elements_map)      \
-  V(function_context_map)               \
-  V(catch_context_map)                  \
-  V(with_context_map)                   \
-  V(block_context_map)                  \
-  V(module_context_map)                 \
-  V(global_context_map)                 \
-  V(undefined_map)                      \
-  V(the_hole_map)                       \
-  V(null_map)                           \
-  V(boolean_map)                        \
-  V(uninitialized_map)                  \
-  V(message_object_map)                 \
-  V(foreign_map)                        \
-  V(neander_map)
-
 #define INTERNALIZED_STRING_LIST(V)                        \
   V(Object_string, "Object")                               \
   V(proto_string, "__proto__")                             \
   V(arguments_string, "arguments")                         \
   V(Arguments_string, "Arguments")                         \
   V(caller_string, "caller")                               \
   V(boolean_string, "boolean")                             \
   V(Boolean_string, "Boolean")                             \
   V(callee_string, "callee")                               \
   V(constructor_string, "constructor")                     \
@@ skipping 81 matching lines @@
   V(normal_ic_symbol)               \
   V(home_object_symbol)             \
   V(intl_initialized_marker_symbol) \
   V(intl_impl_object_symbol)        \
   V(promise_debug_marker_symbol)    \
   V(promise_has_handler_symbol)     \
   V(class_script_symbol)            \
   V(class_start_position_symbol)    \
   V(class_end_position_symbol)
 
+// Heap roots that are known to be immortal immovable, for which we can safely
+// skip write barriers. This list is not complete and has omissions.
+#define IMMORTAL_IMMOVABLE_ROOT_LIST(V) \
+  V(ByteArrayMap)                       \
+  V(FreeSpaceMap)                       \
+  V(OnePointerFillerMap)                \
+  V(TwoPointerFillerMap)                \
+  V(UndefinedValue)                     \
+  V(TheHoleValue)                       \
+  V(NullValue)                          \
+  V(TrueValue)                          \
+  V(FalseValue)                         \
+  V(UninitializedValue)                 \
+  V(CellMap)                            \
+  V(GlobalPropertyCellMap)              \
+  V(SharedFunctionInfoMap)              \
+  V(MetaMap)                            \
+  V(HeapNumberMap)                      \
+  V(MutableHeapNumberMap)               \
+  V(NativeContextMap)                   \
+  V(FixedArrayMap)                      \
+  V(CodeMap)                            \
+  V(ScopeInfoMap)                       \
+  V(FixedCOWArrayMap)                   \
+  V(FixedDoubleArrayMap)                \
+  V(ConstantPoolArrayMap)               \
+  V(WeakCellMap)                        \
+  V(NoInterceptorResultSentinel)        \
+  V(HashTableMap)                       \
+  V(OrderedHashTableMap)                \
+  V(EmptyFixedArray)                    \
+  V(EmptyByteArray)                     \
+  V(EmptyDescriptorArray)               \
+  V(EmptyConstantPoolArray)             \
+  V(ArgumentsMarker)                    \
+  V(SymbolMap)                          \
+  V(SloppyArgumentsElementsMap)         \
+  V(FunctionContextMap)                 \
+  V(CatchContextMap)                    \
+  V(WithContextMap)                     \
+  V(BlockContextMap)                    \
+  V(ModuleContextMap)                   \
+  V(GlobalContextMap)                   \
+  V(UndefinedMap)                       \
+  V(TheHoleMap)                         \
+  V(NullMap)                            \
+  V(BooleanMap)                         \
+  V(UninitializedMap)                   \
+  V(ArgumentsMarkerMap)                 \
+  V(JSMessageObjectMap)                 \
+  V(ForeignMap)                         \
+  V(NeanderMap)                         \
+  PRIVATE_SYMBOL_LIST(V)
+
 // Forward declarations.
 class HeapStats;
 class Isolate;
 class WeakObjectRetainer;
 
 
 typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap,
                                                       Object** pointer);
 
 class StoreBufferRebuilder {
@@ skipping 557 matching lines @@
     roots_[kMaterializedObjectsRootIndex] = objects;
   }
 
   // Generated code can embed this address to get access to the roots.
   Object** roots_array_start() { return roots_; }
 
   Address* store_buffer_top_address() {
     return reinterpret_cast<Address*>(&roots_[kStoreBufferTopRootIndex]);
   }
 
+  static bool RootIsImmortalImmovable(int root_index);
+
 #ifdef VERIFY_HEAP
   // Verify the heap is in its normal state before or after a GC.
   void Verify();
 
 
   bool weak_embedded_objects_verification_enabled() {
     return no_weak_object_verification_scope_depth_ == 0;
   }
 #endif
 
@@ skipping 168 matching lines @@
     kStringTableRootIndex,
 
 #define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
     SMI_ROOT_LIST(ROOT_INDEX_DECLARATION)
 #undef ROOT_INDEX_DECLARATION
     kRootListLength,
     kStrongRootListLength = kStringTableRootIndex,
     kSmiRootsStart = kStringTableRootIndex + 1
   };
 
+  Object* root(RootListIndex index) { return roots_[index]; }
+
   STATIC_ASSERT(kUndefinedValueRootIndex ==
                 Internals::kUndefinedValueRootIndex);
   STATIC_ASSERT(kNullValueRootIndex == Internals::kNullValueRootIndex);
   STATIC_ASSERT(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
   STATIC_ASSERT(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
   STATIC_ASSERT(kempty_stringRootIndex == Internals::kEmptyStringRootIndex);
 
   // Generated code can embed direct references to non-writable roots if
   // they are in new space.
   static bool RootCanBeWrittenAfterInitialization(RootListIndex root_index);
@@ skipping 1419 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_