[explicit isolates] Convert regexp, debug and snapshot to use ReadOnlyRoots

In future the RO_SPACE root accessors in Heap will become private, so
instead convert them all to use ReadOnlyRoots.

Bug: v8:7786
Change-Id: I631fa1e44d2b9998a5567c96c6977955ac86d5a1
Reviewed-on: https://chromium-review.googlesource.com/1125931
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54215}

src/debug/debug-coverage.cc

@@ -575,7 +575,7 @@ void Coverage::SelectMode(Isolate* isolate, debug::Coverage::Mode mode) {
       isolate->debug()->RemoveAllCoverageInfos();
       if (!isolate->is_collecting_type_profile()) {
         isolate->SetFeedbackVectorsForProfilingTools(
-            isolate->heap()->undefined_value());
+            ReadOnlyRoots(isolate).undefined_value());
       }
       break;
     case debug::Coverage::kBlockBinary:

src/debug/debug-scopes.cc

@@ -778,7 +778,7 @@ bool ScopeIterator::SetLocalVariableValue(Handle<String> variable_name,
         case VariableLocation::UNALLOCATED:
           // Drop assignments to unallocated locals.
           DCHECK(var->is_this() ||
-                 *variable_name == isolate_->heap()->arguments_string());
+                 *variable_name == ReadOnlyRoots(isolate_).arguments_string());
           return false;
 
         case VariableLocation::PARAMETER: {

src/debug/debug-type-profile.cc

@@ -100,7 +100,7 @@ void TypeProfile::SelectMode(Isolate* isolate, debug::TypeProfile::Mode mode) {
       // coverage.
       if (isolate->is_best_effort_code_coverage()) {
         isolate->SetFeedbackVectorsForProfilingTools(
-            isolate->heap()->undefined_value());
+            ReadOnlyRoots(isolate).undefined_value());
       }
     }
   } else {

src/debug/debug.cc

@@ -2194,7 +2194,7 @@ void Debug::StopSideEffectCheckMode() {
   DCHECK(isolate_->debug_execution_mode() == DebugInfo::kSideEffects);
   if (side_effect_check_failed_) {
     DCHECK(isolate_->has_pending_exception());
-    DCHECK_EQ(isolate_->heap()->termination_exception(),
+    DCHECK_EQ(ReadOnlyRoots(isolate_).termination_exception(),
               isolate_->pending_exception());
     // Convert the termination exception into a regular exception.
     isolate_->CancelTerminateExecution();

src/regexp/jsregexp.cc

@@ -6872,7 +6872,8 @@ void RegExpResultsCache::Enter(Isolate* isolate, Handle<String> key_string,
     }
   }
   // Convert backing store to a copy-on-write array.
-  value_array->set_map_no_write_barrier(isolate->heap()->fixed_cow_array_map());
+  value_array->set_map_no_write_barrier(
+      ReadOnlyRoots(isolate).fixed_cow_array_map());
 }
 
 

src/regexp/jsregexp.h

@@ -1514,7 +1514,7 @@ class RegExpEngine: public AllStatic {
   struct CompilationResult {
     CompilationResult(Isolate* isolate, const char* error_message)
         : error_message(error_message),
-          code(isolate->heap()->the_hole_value()),
+          code(ReadOnlyRoots(isolate).the_hole_value()),
           num_registers(0) {}
     CompilationResult(Object* code, int registers)
         : error_message(nullptr), code(code), num_registers(registers) {}

src/snapshot/code-serializer.cc

@@ -164,29 +164,29 @@ void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
     UNREACHABLE();
   }
 
+  ReadOnlyRoots roots(isolate());
   if (ElideObject(obj)) {
-    return SerializeObject(isolate()->heap()->undefined_value(), how_to_code,
-                           where_to_point, skip);
+    return SerializeObject(roots.undefined_value(), how_to_code, where_to_point,
+                           skip);
   }
 
   if (obj->IsScript()) {
     Script* script_obj = Script::cast(obj);
     DCHECK_NE(script_obj->compilation_type(), Script::COMPILATION_TYPE_EVAL);
     // Wrapper object is a context-dependent JSValue. Reset it here.
-    script_obj->set_wrapper(isolate()->heap()->undefined_value());
+    script_obj->set_wrapper(roots.undefined_value());
     // We want to differentiate between undefined and uninitialized_symbol for
     // context_data for now. It is hack to allow debugging for scripts that are
     // included as a part of custom snapshot. (see debug::Script::IsEmbedded())
     Object* context_data = script_obj->context_data();
-    if (context_data != isolate()->heap()->undefined_value() &&
-        context_data != isolate()->heap()->uninitialized_symbol()) {
-      script_obj->set_context_data(isolate()->heap()->undefined_value());
+    if (context_data != roots.undefined_value() &&
+        context_data != roots.uninitialized_symbol()) {
+      script_obj->set_context_data(roots.undefined_value());
     }
     // We don't want to serialize host options to avoid serializing unnecessary
     // object graph.
     FixedArray* host_options = script_obj->host_defined_options();
-    script_obj->set_host_defined_options(
-        isolate()->heap()->empty_fixed_array());
+    script_obj->set_host_defined_options(roots.empty_fixed_array());
     SerializeGeneric(obj, how_to_code, where_to_point);
     script_obj->set_host_defined_options(host_options);
     script_obj->set_context_data(context_data);
@@ -315,7 +315,7 @@ MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize(
 
   if (isolate->logger()->is_listening_to_code_events() ||
       isolate->is_profiling()) {
-    String* name = isolate->heap()->empty_string();
+    String* name = ReadOnlyRoots(isolate).empty_string();
     if (result->script()->IsScript()) {
       Script* script = Script::cast(result->script());
       if (script->name()->IsString()) name = String::cast(script->name());

src/snapshot/default-deserializer-allocator.cc

@@ -71,9 +71,9 @@ Address DefaultDeserializerAllocator::Allocate(AllocationSpace space,
     // aligned object when the filler maps have not been deserialized yet.
     // We require filler maps as padding to align the object.
     Heap* heap = isolate()->heap();
-    DCHECK(heap->free_space_map()->IsMap());
-    DCHECK(heap->one_pointer_filler_map()->IsMap());
-    DCHECK(heap->two_pointer_filler_map()->IsMap());
+    DCHECK(ReadOnlyRoots(heap).free_space_map()->IsMap());
+    DCHECK(ReadOnlyRoots(heap).one_pointer_filler_map()->IsMap());
+    DCHECK(ReadOnlyRoots(heap).two_pointer_filler_map()->IsMap());
     obj = heap->AlignWithFiller(obj, size, reserved, next_alignment_);
     address = obj->address();
     next_alignment_ = kWordAligned;

src/snapshot/deserializer.cc

@@ -182,7 +182,7 @@ HeapObject* Deserializer<AllocatorT>::PostProcessNewObject(HeapObject* obj,
     // as a (weak) root. If this root is relocated correctly, this becomes
     // unnecessary.
     if (isolate_->heap()->allocation_sites_list() == Smi::kZero) {
-      site->set_weak_next(isolate_->heap()->undefined_value());
+      site->set_weak_next(ReadOnlyRoots(isolate_).undefined_value());
     } else {
       site->set_weak_next(isolate_->heap()->allocation_sites_list());
     }
@@ -203,7 +203,7 @@ HeapObject* Deserializer<AllocatorT>::PostProcessNewObject(HeapObject* obj,
     call_handler_infos_.push_back(CallHandlerInfo::cast(obj));
 #endif
   } else if (obj->IsExternalString()) {
-    if (obj->map() == isolate_->heap()->native_source_string_map()) {
+    if (obj->map() == ReadOnlyRoots(isolate_).native_source_string_map()) {
       ExternalOneByteString* string = ExternalOneByteString::cast(obj);
       DCHECK(string->is_short());
       string->set_resource(

src/snapshot/partial-serializer.cc

@@ -37,11 +37,11 @@ void PartialSerializer::Serialize(Context** o, bool include_global_proxy) {
   // it before serializing, it will get re-added to the context list
   // explicitly when it's loaded.
   context_->set(Context::NEXT_CONTEXT_LINK,
-                isolate()->heap()->undefined_value());
+                ReadOnlyRoots(isolate()).undefined_value());
   DCHECK(!context_->global_object()->IsUndefined());
   // Reset math random cache to get fresh random numbers.
   context_->set_math_random_index(Smi::kZero);
-  context_->set_math_random_cache(isolate()->heap()->undefined_value());
+  context_->set_math_random_cache(ReadOnlyRoots(isolate()).undefined_value());
 
   VisitRootPointer(Root::kPartialSnapshotCache, nullptr,
                    reinterpret_cast<Object**>(o));
@@ -125,8 +125,8 @@ bool PartialSerializer::ShouldBeInThePartialSnapshotCache(HeapObject* o) {
   return o->IsName() || o->IsSharedFunctionInfo() || o->IsHeapNumber() ||
          o->IsCode() || o->IsScopeInfo() || o->IsAccessorInfo() ||
          o->IsTemplateInfo() ||
-         o->map() ==
-             startup_serializer_->isolate()->heap()->fixed_cow_array_map();
+         o->map() == ReadOnlyRoots(startup_serializer_->isolate())
+                         .fixed_cow_array_map();
 }
 
 void PartialSerializer::SerializeEmbedderFields() {

src/snapshot/serializer.cc

@@ -500,7 +500,7 @@ void Serializer<AllocatorT>::ObjectSerializer::SerializeExternalString() {
   // for native native source code strings, we replace the resource field
   // with the native source id.
   // For the rest we serialize them to look like ordinary sequential strings.
-  if (object_->map() != heap->native_source_string_map()) {
+  if (object_->map() != ReadOnlyRoots(heap).native_source_string_map()) {
     ExternalString* string = ExternalString::cast(object_);
     Address resource = string->resource_as_address();
     ExternalReferenceEncoder::Value reference;
@@ -532,9 +532,9 @@ void Serializer<
     AllocatorT>::ObjectSerializer::SerializeExternalStringAsSequentialString() {
   // Instead of serializing this as an external string, we serialize
   // an imaginary sequential string with the same content.
-  Isolate* isolate = serializer_->isolate();
+  ReadOnlyRoots roots(serializer_->isolate());
   DCHECK(object_->IsExternalString());
-  DCHECK(object_->map() != isolate->heap()->native_source_string_map());
+  DCHECK(object_->map() != roots.native_source_string_map());
   ExternalString* string = ExternalString::cast(object_);
   int length = string->length();
   Map* map;
@@ -544,15 +544,14 @@ void Serializer<
   // Find the map and size for the imaginary sequential string.
   bool internalized = object_->IsInternalizedString();
   if (object_->IsExternalOneByteString()) {
-    map = internalized ? isolate->heap()->one_byte_internalized_string_map()
-                       : isolate->heap()->one_byte_string_map();
+    map = internalized ? roots.one_byte_internalized_string_map()
+                       : roots.one_byte_string_map();
     allocation_size = SeqOneByteString::SizeFor(length);
     content_size = length * kCharSize;
     resource = reinterpret_cast<const byte*>(
         ExternalOneByteString::cast(string)->resource()->data());
   } else {
-    map = internalized ? isolate->heap()->internalized_string_map()
-                       : isolate->heap()->string_map();
+    map = internalized ? roots.internalized_string_map() : roots.string_map();
     allocation_size = SeqTwoByteString::SizeFor(length);
     content_size = length * kShortSize;
     resource = reinterpret_cast<const byte*>(
@@ -595,7 +594,8 @@ class UnlinkWeakNextScope {
     if (object->IsAllocationSite()) {
       object_ = object;
       next_ = AllocationSite::cast(object)->weak_next();
-      AllocationSite::cast(object)->set_weak_next(heap->undefined_value());
+      AllocationSite::cast(object)->set_weak_next(
+          ReadOnlyRoots(heap).undefined_value());
     }
   }
 
@@ -648,7 +648,7 @@ void Serializer<AllocatorT>::ObjectSerializer::Serialize() {
 
   if (object_->IsScript()) {
     // Clear cached line ends.
-    Object* undefined = serializer_->isolate()->heap()->undefined_value();
+    Object* undefined = ReadOnlyRoots(serializer_->isolate()).undefined_value();
     Script::cast(object_)->set_line_ends(undefined);
   }
 

src/snapshot/startup-deserializer.cc

@@ -52,12 +52,13 @@ void StartupDeserializer::DeserializeInto(Isolate* isolate) {
     FlushICacheForNewIsolate();
   }
 
-  isolate->heap()->set_native_contexts_list(isolate->heap()->undefined_value());
+  isolate->heap()->set_native_contexts_list(
+      ReadOnlyRoots(isolate).undefined_value());
   // The allocation site list is build during root iteration, but if no sites
   // were encountered then it needs to be initialized to undefined.
   if (isolate->heap()->allocation_sites_list() == Smi::kZero) {
     isolate->heap()->set_allocation_sites_list(
-        isolate->heap()->undefined_value());
+        ReadOnlyRoots(isolate).undefined_value());
   }
 
   // Issue code events for newly deserialized code objects.

src/snapshot/startup-serializer.cc

@@ -65,12 +65,12 @@ void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
     call_handler_infos_.push_back(info);
   } else if (obj->IsScript() && Script::cast(obj)->IsUserJavaScript()) {
     Script::cast(obj)->set_context_data(
-        isolate()->heap()->uninitialized_symbol());
+        ReadOnlyRoots(isolate()).uninitialized_symbol());
   } else if (obj->IsSharedFunctionInfo()) {
     // Clear inferred name for native functions.
     SharedFunctionInfo* shared = SharedFunctionInfo::cast(obj);
     if (!shared->IsSubjectToDebugging() && shared->HasInferredName()) {
-      shared->set_inferred_name(isolate()->heap()->empty_string());
+      shared->set_inferred_name(ReadOnlyRoots(isolate()).empty_string());
     }
   }
 
@@ -86,7 +86,7 @@ void StartupSerializer::SerializeWeakReferencesAndDeferred() {
   // This comes right after serialization of the partial snapshot, where we
   // add entries to the partial snapshot cache of the startup snapshot. Add
   // one entry with 'undefined' to terminate the partial snapshot cache.
-  Object* undefined = isolate()->heap()->undefined_value();
+  Object* undefined = ReadOnlyRoots(isolate()).undefined_value();
   VisitRootPointer(Root::kPartialSnapshotCache, nullptr, &undefined);
   isolate()->heap()->IterateWeakRoots(this, VISIT_FOR_SERIALIZATION);
   SerializeDeferredObjects();