[parser]: Skipping inner funcs / initial implemetation of storing scope analysis data from preparse…

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/ast/ast.h"
 #include "src/bootstrapper.h"
 #include "src/counters.h"
 #include "src/messages.h"
 #include "src/objects-inl.h"
 #include "src/objects/module-info.h"
 #include "src/parsing/parse-info.h"
+#include "src/parsing/preparsed-scope-data.h"
 
 namespace v8 {
 namespace internal {
 
 namespace {
 void* kDummyPreParserVariable = reinterpret_cast<void*>(0x1);
 void* kDummyPreParserLexicalVariable = reinterpret_cast<void*>(0x2);
 
 bool IsLexical(Variable* variable) {
   if (variable == kDummyPreParserLexicalVariable) return true;
@@ skipping 1342 matching lines @@
   }
 
 #ifdef DEBUG
   needs_migration_ = false;
   is_being_lazily_parsed_ = false;
 #endif
 
   was_lazily_parsed_ = !aborted;
 }
 
-void DeclarationScope::AnalyzePartially(AstNodeFactory* ast_node_factory) {
+void DeclarationScope::AnalyzePartially(
+    AstNodeFactory* ast_node_factory,
+    PreParsedScopeData* preparsed_scope_data) {

[vogelheim, 2017/01/25 10:00:17]

DCHECK_EQ(FLAG_preparser_scope_analysis, preparsed_scope_data != nullptr);

(Or is this not the right invariant?)

[marja, 2017/01/25 10:21:26]

It's not, since PreParsedScopeData always exists (it's a member of ParseInfo)
even without the flag. I could also not thread it through here unless the flag
is on (so I'd check the flag in Parser ctor or in ParseFunctionLiteral) but that
seems an unnecessary check.

   DCHECK(!force_eager_compilation_);
   VariableProxy* unresolved = nullptr;
 
   if (!outer_scope_->is_script_scope()) {
     // Try to resolve unresolved variables for this Scope and migrate those
     // which cannot be resolved inside. It doesn't make sense to try to resolve
     // them in the outer Scopes here, because they are incomplete.
     for (VariableProxy* proxy = FetchFreeVariables(this); proxy != nullptr;
          proxy = proxy->next_unresolved()) {
       DCHECK(!proxy->is_resolved());
       VariableProxy* copy = ast_node_factory->CopyVariableProxy(proxy);
       copy->set_next_unresolved(unresolved);
       unresolved = copy;
     }
 
     // Clear arguments_ if unused. This is used as a signal for optimization.
     if (arguments_ != nullptr &&
         !(MustAllocate(arguments_) && !has_arguments_parameter_)) {
       arguments_ = nullptr;
     }
+
+    if (FLAG_preparser_scope_analysis) {
+      // Decide context allocation for the locals and parameters and store the
+      // info away.
+      AllocateVariablesRecursively();
+      GetAllocationData(preparsed_scope_data);
+    }
   }
 
   ResetAfterPreparsing(ast_node_factory->ast_value_factory(), false);
 
   unresolved_ = unresolved;
 }
 
 #ifdef DEBUG
 namespace {
 
@@ skipping 733 matching lines @@
   if (scope_info_.is_null()) {
     scope_info_ = ScopeInfo::Create(isolate, zone(), this, outer_scope);
   }
   MaybeHandle<ScopeInfo> outer = NeedsContext() ? scope_info_ : outer_scope;
   for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
     if (scope->is_function_scope()) continue;
     scope->AllocateDebuggerScopeInfos(isolate, outer);
   }
 }
 
+void Scope::GetAllocationData(PreParsedScopeData* data) {

[vogelheim, 2017/01/25 10:00:18]

naming nitpick: This doesn't really get anything...  Maybe
CollectAllocationDataFromInnerScopes... or something shorter? :)

[marja, 2017/01/25 10:21:26]

Went for CollectVariableData (no "FromInenrScopes" since it also collects from
this scope).

+  PreParsedScopeData::ScopeData scope_data(data, scope_type(), start_position(),
+                                           end_position());
+  // TODO(marja): Add data about the variables.
+  for (Scope* inner = inner_scope_; inner != nullptr; inner = inner->sibling_) {
+    inner->GetAllocationData(data);
+  }

[vogelheim, 2017/01/25 10:00:18]

nitpick: I found this code a bit weird to read... this iterates over the tree of
inner scopes (relative to the calling DeclarationScope::AnalyzePartially), but
it doesn't seem to actually do anything. Until I remembered that the ScopeData
constructor effectively builds up a chain of scope data referenced from within
*data.

[marja, 2017/01/25 10:21:26]

Acknowledged.

+}
+
 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 -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8