[explicit isolates] Add Handle getters to ReadOnlyRoots

Add <root>_handle getters to ReadOnlyRoots, so an Isolate isn't required
to get a handle of a root.

Also convert one GetIsolate()->factory()->accessor() to
GetReadOnlyRoots().accessor_handle() in FixedArray.

Bug: v8:7786
Change-Id: I1b72c58f90eacf64be95abb65df91cf993178a93
Reviewed-on: https://chromium-review.googlesource.com/1129225
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54334}

src/objects.cc

@@ -10250,7 +10250,7 @@ bool FixedArray::ContainsSortedNumbers() {
 Handle<FixedArray> FixedArray::ShrinkOrEmpty(Handle<FixedArray> array,
                                              int new_length) {
   if (new_length == 0) {
-    return array->GetIsolate()->factory()->empty_fixed_array();
+    return array->GetReadOnlyRoots().empty_fixed_array_handle();
   } else {
     array->Shrink(new_length);
     return array;

src/roots-inl.h

@@ -19,6 +19,10 @@ ReadOnlyRoots::ReadOnlyRoots(Isolate* isolate) : heap_(isolate->heap()) {}
 #define ROOT_ACCESSOR(type, name, camel_name)                              \
   type* ReadOnlyRoots::name() {                                            \
     return type::cast(heap_->roots_[Heap::k##camel_name##RootIndex]);      \
+  }                                                                        \
+  Handle<type> ReadOnlyRoots::name##_handle() {                            \
+    return Handle<type>(                                                   \
+        bit_cast<type**>(&heap_->roots_[Heap::k##camel_name##RootIndex])); \
   }
 STRONG_READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
@@ -26,6 +30,10 @@ STRONG_READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
 #define STRING_ACCESSOR(name, str)                                     \
   String* ReadOnlyRoots::name() {                                      \
     return String::cast(heap_->roots_[Heap::k##name##RootIndex]);      \
+  }                                                                    \
+  Handle<String> ReadOnlyRoots::name##_handle() {                      \
+    return Handle<String>(                                             \
+        bit_cast<String**>(&heap_->roots_[Heap::k##name##RootIndex])); \
   }
 INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
 #undef STRING_ACCESSOR
@@ -33,6 +41,10 @@ INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
 #define SYMBOL_ACCESSOR(name)                                          \
   Symbol* ReadOnlyRoots::name() {                                      \
     return Symbol::cast(heap_->roots_[Heap::k##name##RootIndex]);      \
+  }                                                                    \
+  Handle<Symbol> ReadOnlyRoots::name##_handle() {                      \
+    return Handle<Symbol>(                                             \
+        bit_cast<Symbol**>(&heap_->roots_[Heap::k##name##RootIndex])); \
   }
 PRIVATE_SYMBOL_LIST(SYMBOL_ACCESSOR)
 #undef SYMBOL_ACCESSOR
@@ -40,6 +52,10 @@ PRIVATE_SYMBOL_LIST(SYMBOL_ACCESSOR)
 #define SYMBOL_ACCESSOR(name, description)                             \
   Symbol* ReadOnlyRoots::name() {                                      \
     return Symbol::cast(heap_->roots_[Heap::k##name##RootIndex]);      \
+  }                                                                    \
+  Handle<Symbol> ReadOnlyRoots::name##_handle() {                      \
+    return Handle<Symbol>(                                             \
+        bit_cast<Symbol**>(&heap_->roots_[Heap::k##name##RootIndex])); \
   }
 PUBLIC_SYMBOL_LIST(SYMBOL_ACCESSOR)
 WELL_KNOWN_SYMBOL_LIST(SYMBOL_ACCESSOR)
@@ -48,6 +64,10 @@ WELL_KNOWN_SYMBOL_LIST(SYMBOL_ACCESSOR)
 #define STRUCT_MAP_ACCESSOR(NAME, Name, name)                          \
   Map* ReadOnlyRoots::name##_map() {                                   \
     return Map::cast(heap_->roots_[Heap::k##Name##MapRootIndex]);      \
+  }                                                                    \
+  Handle<Map> ReadOnlyRoots::name##_map_handle() {                     \
+    return Handle<Map>(                                                \
+        bit_cast<Map**>(&heap_->roots_[Heap::k##Name##MapRootIndex])); \
   }
 STRUCT_LIST(STRUCT_MAP_ACCESSOR)
 #undef STRUCT_MAP_ACCESSOR
@@ -55,6 +75,10 @@ STRUCT_LIST(STRUCT_MAP_ACCESSOR)
 #define ALLOCATION_SITE_MAP_ACCESSOR(NAME, Name, Size, name)                 \
   Map* ReadOnlyRoots::name##_map() {                                         \
     return Map::cast(heap_->roots_[Heap::k##Name##Size##MapRootIndex]);      \
+  }                                                                          \
+  Handle<Map> ReadOnlyRoots::name##_map_handle() {                           \
+    return Handle<Map>(                                                      \
+        bit_cast<Map**>(&heap_->roots_[Heap::k##Name##Size##MapRootIndex])); \
   }
 ALLOCATION_SITE_LIST(ALLOCATION_SITE_MAP_ACCESSOR)
 #undef ALLOCATION_SITE_MAP_ACCESSOR

src/roots.h

@@ -5,6 +5,7 @@
 #ifndef V8_ROOTS_H_
 #define V8_ROOTS_H_
 
+#include "src/handles.h"
 #include "src/heap-symbols.h"
 #include "src/objects-definitions.h"
 
@@ -289,6 +290,7 @@ namespace internal {
 
 class Heap;
 class Isolate;
+class Map;
 class String;
 class Symbol;
 
@@ -297,30 +299,41 @@ class ReadOnlyRoots {
   explicit ReadOnlyRoots(Heap* heap) : heap_(heap) {}
   inline explicit ReadOnlyRoots(Isolate* isolate);
 
-#define ROOT_ACCESSOR(type, name, camel_name) inline class type* name();
+#define ROOT_ACCESSOR(type, name, camel_name) \
+  inline class type* name();                  \
+  inline Handle<type> name##_handle();
   STRONG_READ_ONLY_ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
-#define STRING_ACCESSOR(name, str) inline String* name();
+#define STRING_ACCESSOR(name, str) \
+  inline String* name();           \
+  inline Handle<String> name##_handle();
   INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
 #undef STRING_ACCESSOR
 
-#define SYMBOL_ACCESSOR(name) inline Symbol* name();
+#define SYMBOL_ACCESSOR(name) \
+  inline Symbol* name();      \
+  inline Handle<Symbol> name##_handle();
   PRIVATE_SYMBOL_LIST(SYMBOL_ACCESSOR)
 #undef SYMBOL_ACCESSOR
 
-#define SYMBOL_ACCESSOR(name, description) inline Symbol* name();
+#define SYMBOL_ACCESSOR(name, description) \
+  inline Symbol* name();                   \
+  inline Handle<Symbol> name##_handle();
   PUBLIC_SYMBOL_LIST(SYMBOL_ACCESSOR)
   WELL_KNOWN_SYMBOL_LIST(SYMBOL_ACCESSOR)
 #undef SYMBOL_ACCESSOR
 
 // Utility type maps.
-#define STRUCT_MAP_ACCESSOR(NAME, Name, name) inline Map* name##_map();
+#define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
+  inline Map* name##_map();                   \
+  inline class Handle<Map> name##_map_handle();
   STRUCT_LIST(STRUCT_MAP_ACCESSOR)
 #undef STRUCT_MAP_ACCESSOR
 
 #define ALLOCATION_SITE_MAP_ACCESSOR(NAME, Name, Size, name) \
-  inline Map* name##_map();
+  inline Map* name##_map();                                  \
+  inline class Handle<Map> name##_map_handle();
   ALLOCATION_SITE_LIST(ALLOCATION_SITE_MAP_ACCESSOR)
 #undef ALLOCATION_SITE_MAP_ACCESSOR