Create ScopeInfos while analyzing the Scope chain

src/ast/scopes.cc

 // 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.
 
 #include "src/ast/scopes.h"
 
 #include <set>
 
 #include "src/accessors.h"
 #include "src/bootstrapper.h"
@@ skipping 793 matching lines @@
       stack_locals->Add(var, zone());
     } else if (var->IsContextSlot()) {
       context_locals->Add(var, zone());
     } else if (var->IsGlobalSlot()) {
       context_globals->Add(var, zone());
     }
   }
 }
 
 void DeclarationScope::AllocateVariables(ParseInfo* info) {
-  // 1) Propagate scope information.
   PropagateScopeInfo();
-
-  // 2) Resolve variables.
   ResolveVariablesRecursively(info);
-
-  // 3) Allocate variables.
   AllocateVariablesRecursively();
+  AllocateScopeInfosRecursively(info);
 }
 
 
 bool Scope::AllowsLazyParsing() const {
   // If we are inside a block scope, we must parse eagerly to find out how
   // to allocate variables on the block scope. At this point, declarations may
   // not have yet been parsed.
   for (const Scope* s = this; s != nullptr; s = s->outer_scope_) {
     if (s->is_block_scope()) return false;
   }
@@ skipping 68 matching lines @@
 DeclarationScope* Scope::GetReceiverScope() {
   Scope* scope = this;
   while (!scope->is_script_scope() &&
          (!scope->is_function_scope() ||
           scope->AsDeclarationScope()->is_arrow_scope())) {
     scope = scope->outer_scope();
   }
   return scope->AsDeclarationScope();
 }
 
-
-
-Handle<ScopeInfo> Scope::GetScopeInfo(Isolate* isolate) {
-  if (scope_info_.is_null()) {
-    scope_info_ = ScopeInfo::Create(isolate, zone(), this);
-  }
-  return scope_info_;
-}
-
 Handle<StringSet> DeclarationScope::CollectNonLocals(
     ParseInfo* info, Handle<StringSet> non_locals) {
   VariableProxy* free_variables = FetchFreeVariables(this, info);
   for (VariableProxy* proxy = free_variables; proxy != nullptr;
        proxy = proxy->next_unresolved()) {
     non_locals = StringSet::Add(non_locals, proxy->name());
   }
   return non_locals;
 }
 
@@ skipping 663 matching lines @@
   // If we didn't allocate any locals in the local context, then we only
   // need the minimal number of slots if we must have a context.
   if (num_heap_slots_ == Context::MIN_CONTEXT_SLOTS && !must_have_context) {
     num_heap_slots_ = 0;
   }
 
   // Allocation done.
   DCHECK(num_heap_slots_ == 0 || num_heap_slots_ >= Context::MIN_CONTEXT_SLOTS);
 }
 
+void Scope::AllocateScopeInfosRecursively(ParseInfo* info) {
+  DCHECK(scope_info_.is_null());

[marja, 2016/08/29 10:49:30]

Discussed offline: maybe we should create ScopeInfos only for those Scopes which
need them, not for all. The chained-together-ScopeInfos will also only contain
those ones which are needed, and the rest will be discarded.

+  scope_info_ = ScopeInfo::Create(info->isolate(), zone(), this);

[Toon Verwaest, 2016/08/29 11:46:25]

Wut? We pass along info just to get the isolate?

[jochen (gone - plz use gerrit), 2016/08/29 12:15:25]

Eventually, I'd like get the ScopeInfo of the outer scope chain from the
ParseInfo, but I can also change Isolate* to ParseInfo* then

+
+  // Allocate ScopeInfos for inner scopes.
+  for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
+    scope->AllocateScopeInfosRecursively(info);
+  }
+}
 
 int Scope::StackLocalCount() const {
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   return num_stack_slots() -
          (function != nullptr && function->IsStackLocal() ? 1 : 0);
 }
 
 
 int Scope::ContextLocalCount() const {
   if (num_heap_slots() == 0) return 0;
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS - num_global_slots() -
          (is_function_var_in_context ? 1 : 0);
 }
 
 
 int Scope::ContextGlobalCount() const { return num_global_slots(); }
 
 }  // namespace internal
 }  // namespace v8