[sandbox] Properly initialize LocalFactory::isolate_for_sandbox

This is required when allocating external pointer table entries from
background threads through the LocalFactory interface.

Bug: v8:10391
Change-Id: Ice5eee1000e1c7341bd0e58782cbb175080a5a74
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3448376Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79010}

src/heap/factory-base.cc

@@ -82,10 +82,10 @@ Handle<CodeDataContainer> FactoryBase<Impl>::NewCodeDataContainer(
   data_container.set_kind_specific_flags(flags, kRelaxedStore);
   if (V8_EXTERNAL_CODE_SPACE_BOOL) {
     data_container.set_code_cage_base(impl()->isolate()->code_cage_base());
-    Isolate* isolate_for_heap_sandbox = impl()->isolate_for_heap_sandbox();
-    data_container.AllocateExternalPointerEntries(isolate_for_heap_sandbox);
+    Isolate* isolate_for_sandbox = impl()->isolate_for_sandbox();
+    data_container.AllocateExternalPointerEntries(isolate_for_sandbox);
     data_container.set_raw_code(Smi::zero(), SKIP_WRITE_BARRIER);
-    data_container.set_code_entry_point(isolate_for_heap_sandbox, kNullAddress);
+    data_container.set_code_entry_point(isolate_for_sandbox, kNullAddress);
   }
   data_container.clear_padding();
   return handle(data_container, isolate());

src/heap/factory.h

@@ -1021,7 +1021,7 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
 
   // This is the real Isolate that will be used for allocating and accessing
   // external pointer entries when V8_SANDBOXED_EXTERNAL_POINTERS is enabled.
-  Isolate* isolate_for_heap_sandbox() const {
+  Isolate* isolate_for_sandbox() const {
 #ifdef V8_SANDBOXED_EXTERNAL_POINTERS
     return isolate();
 #else

src/heap/local-factory.cc

@@ -19,7 +19,12 @@
 namespace v8 {
 namespace internal {
 
+#ifdef V8_SANDBOXED_EXTERNAL_POINTERS
+LocalFactory::LocalFactory(Isolate* isolate)
+    : roots_(isolate), isolate_for_sandbox_(isolate) {}
+#else
 LocalFactory::LocalFactory(Isolate* isolate) : roots_(isolate) {}
+#endif
 
 void LocalFactory::AddToScriptList(Handle<Script> shared) {
 // TODO(leszeks): Actually add the script to the main Isolate's script list,

src/heap/local-factory.h

@@ -66,9 +66,9 @@ class V8_EXPORT_PRIVATE LocalFactory : public FactoryBase<LocalFactory> {
 
   // This is the real Isolate that will be used for allocating and accessing
   // external pointer entries when V8_SANDBOXED_EXTERNAL_POINTERS is enabled.
-  Isolate* isolate_for_heap_sandbox() {
+  Isolate* isolate_for_sandbox() {
 #ifdef V8_SANDBOXED_EXTERNAL_POINTERS
-    return isolate_for_heap_sandbox_;
+    return isolate_for_sandbox_;
 #else
     return nullptr;
 #endif  // V8_SANDBOXED_EXTERNAL_POINTERS
@@ -84,7 +84,7 @@ class V8_EXPORT_PRIVATE LocalFactory : public FactoryBase<LocalFactory> {
 
   ReadOnlyRoots roots_;
 #ifdef V8_SANDBOXED_EXTERNAL_POINTERS
-  Isolate* isolate_for_heap_sandbox_;
+  Isolate* isolate_for_sandbox_;
 #endif
 #ifdef DEBUG
   bool a_script_was_added_to_the_script_list_ = false;