[debug] Store blocklist on ScopeInfo for DebugEvaluate contexts.

Following up on https://crrev.com/c/1946349, this moves the blocklist to
the ScopeInfo instead of storing it directly on the DebugEvaluate
contexts. This is not the final state that we're looking for, but a
small step along the way.

Bug: chromium:1027475, v8:9938, chromium:1072939
Change-Id: I529f2fcacaf057a1236847bf0eb8e12cc1686515
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2910774Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74724}

src/debug/debug-evaluate.cc

@@ -159,9 +159,8 @@ MaybeHandle<Object> DebugEvaluate::WithTopmostArguments(Isolate* isolate,
   Handle<ScopeInfo> scope_info =
       ScopeInfo::CreateForWithScope(isolate, Handle<ScopeInfo>::null());
   scope_info->SetIsDebugEvaluateScope();
-  Handle<Context> evaluation_context =
-      factory->NewDebugEvaluateContext(native_context, scope_info, materialized,
-                                       Handle<Context>(), Handle<StringSet>());
+  Handle<Context> evaluation_context = factory->NewDebugEvaluateContext(
+      native_context, scope_info, materialized, Handle<Context>());
   Handle<SharedFunctionInfo> outer_info(
       native_context->empty_function().shared(), isolate);
   Handle<JSObject> receiver(native_context->global_proxy(), isolate);
@@ -257,9 +256,13 @@ DebugEvaluate::ContextBuilder::ContextBuilder(Isolate* isolate,
     ContextChainElement element = *rit;
     scope_info = ScopeInfo::CreateForWithScope(isolate, scope_info);
     scope_info->SetIsDebugEvaluateScope();
+    if (!element.blocklist.is_null()) {
+      scope_info = ScopeInfo::RecreateWithBlockList(isolate, scope_info,
+                                                    element.blocklist);
+    }
     evaluation_context_ = factory->NewDebugEvaluateContext(
         evaluation_context_, scope_info, element.materialized_object,
-        element.wrapped_context, element.blocklist);
+        element.wrapped_context);
   }
 }
 

src/heap/factory.cc

@@ -1174,16 +1174,13 @@ Handle<Context> Factory::NewCatchContext(Handle<Context> previous,
 Handle<Context> Factory::NewDebugEvaluateContext(Handle<Context> previous,
                                                  Handle<ScopeInfo> scope_info,
                                                  Handle<JSReceiver> extension,
-                                                 Handle<Context> wrapped,
-                                                 Handle<StringSet> blocklist) {
-  STATIC_ASSERT(Context::BLOCK_LIST_INDEX ==
-                Context::MIN_CONTEXT_EXTENDED_SLOTS + 1);
+                                                 Handle<Context> wrapped) {
   DCHECK(scope_info->IsDebugEvaluateScope());
   Handle<HeapObject> ext = extension.is_null()
                                ? Handle<HeapObject>::cast(undefined_value())
                                : Handle<HeapObject>::cast(extension);
   // TODO(ishell): Take the details from DebugEvaluateContextContext class.
-  int variadic_part_length = Context::MIN_CONTEXT_EXTENDED_SLOTS + 2;
+  int variadic_part_length = Context::MIN_CONTEXT_EXTENDED_SLOTS + 1;
   Context context =
       NewContextInternal(isolate()->debug_evaluate_context_map(),
                          Context::SizeFor(variadic_part_length),
@@ -1196,9 +1193,6 @@ Handle<Context> Factory::NewDebugEvaluateContext(Handle<Context> previous,
   if (!wrapped.is_null()) {
     context.set(Context::WRAPPED_CONTEXT_INDEX, *wrapped, SKIP_WRITE_BARRIER);
   }
-  if (!blocklist.is_null()) {
-    context.set(Context::BLOCK_LIST_INDEX, *blocklist, SKIP_WRITE_BARRIER);
-  }
   return handle(context, isolate());
 }
 

src/heap/factory.h

@@ -342,8 +342,7 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   Handle<Context> NewDebugEvaluateContext(Handle<Context> previous,
                                           Handle<ScopeInfo> scope_info,
                                           Handle<JSReceiver> extension,
-                                          Handle<Context> wrapped,
-                                          Handle<StringSet> blocklist);
+                                          Handle<Context> wrapped);
 
   // Create a block context.
   Handle<Context> NewBlockContext(Handle<Context> previous,

src/objects/contexts.cc

@@ -373,9 +373,9 @@ Handle<Object> Context::Lookup(Handle<Context> context, Handle<String> name,
       }
 
       // Check blocklist. Names that are listed, cannot be resolved further.
-      Object blocklist = context->get(BLOCK_LIST_INDEX);
-      if (blocklist.IsStringSet() &&
-          StringSet::cast(blocklist).Has(isolate, name)) {
+      ScopeInfo scope_info = context->scope_info();
+      if (scope_info.HasLocalsBlockList() &&
+          scope_info.LocalsBlockList().Has(isolate, name)) {
         if (FLAG_trace_contexts) {
           PrintF(" - name is blocklisted. Aborting.\n");
         }

src/objects/contexts.h

@@ -518,8 +518,7 @@ class Context : public TorqueGeneratedContext<Context, HeapObject> {
     THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS,
 
     // These slots hold values in debug evaluate contexts.
-    WRAPPED_CONTEXT_INDEX = MIN_CONTEXT_EXTENDED_SLOTS,
-    BLOCK_LIST_INDEX = MIN_CONTEXT_EXTENDED_SLOTS + 1
+    WRAPPED_CONTEXT_INDEX = MIN_CONTEXT_EXTENDED_SLOTS
   };
 
   static const int kExtensionSize =