Reland of Preparse functions in the scope that was created when parsing of the function was started

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index 04b9daa887e3ffa1aba3fc25d888bc0dd897ba89..966f1efde18ecfa6f17afce414879eb08444e537 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -929,9 +929,12 @@
   {
     // Parse the function literal.
     Scope* outer = original_scope_;
+    DeclarationScope* outer_function = outer->GetClosureScope();
     DCHECK(outer);
-    FunctionState function_state(&function_state_, &scope_state_, outer,
-                                 info->function_kind());
+    FunctionState function_state(&function_state_, &scope_state_,
+                                 outer_function,
+                                 outer_function->function_kind());
+    BlockState block_state(&scope_state_, outer);
     DCHECK(is_sloppy(outer->language_mode()) ||
            is_strict(info->language_mode()));
     FunctionLiteral::FunctionType function_type = ComputeFunctionType(info);
@@ -2940,7 +2943,7 @@
   if (produce_cached_parse_data()) CHECK(log_);
 
   int function_block_pos = position();
-  DeclarationScope* scope = this->scope()->AsDeclarationScope();
+  DeclarationScope* scope = function_state_->scope();
   DCHECK(scope->is_function_scope());
   scope->set_is_lazily_parsed(true);
   // Inner functions are not part of the cached data.
@@ -2973,6 +2976,7 @@
   SingletonLogger logger;
   PreParser::PreParseResult result =
       ParseLazyFunctionBodyWithPreParser(&logger, is_inner_function, may_abort);
+
   // Return immediately if pre-parser decided to abort parsing.
   if (result == PreParser::kPreParseAbort) {
     scope->set_is_lazily_parsed(false);
@@ -3474,32 +3478,13 @@
   // state; we don't parse inner functions in the abortable mode anyway.
   DCHECK(!is_inner_function || !may_abort);
 
-  FunctionKind kind = function_state_->kind();
-  PreParser::PreParseResult result;
-  if (!is_inner_function) {
-    // If we don't need to look at the scope, construct a dummy scope chain
-    // which is not connected to the real scope chain.
-    LanguageMode mode = language_mode();
-    bool has_simple_parameters =
-        scope()->AsDeclarationScope()->has_simple_parameters();
-    DeclarationScope* top_scope = NewScriptScope();
-    top_scope->SetLanguageMode(mode);
-    FunctionState top_state(&function_state_, &scope_state_, top_scope,
-                            kNormalFunction);
-    DeclarationScope* function_scope = NewFunctionScope(kind);
-    if (!has_simple_parameters) {
-      function_scope->SetHasNonSimpleParameters();
-    }
-    result = reusable_preparser_->PreParseLazyFunction(
-        kind, function_scope, parsing_module_, logger, is_inner_function,
-        may_abort, use_counts_);
-  } else {
-    // Detaching the scopes created by PreParser from the Scope chain must be
-    // done above (see ParseFunctionLiteral & AnalyzePartially).
-    result = reusable_preparser_->PreParseLazyFunction(
-        kind, scope()->AsDeclarationScope(), parsing_module_, logger,
-        is_inner_function, may_abort, use_counts_);
-  }
+  DeclarationScope* function_scope = function_state_->scope();
+  PreParser::PreParseResult result = reusable_preparser_->PreParseLazyFunction(
+      function_scope, parsing_module_, logger, is_inner_function, may_abort,
+      use_counts_);
+  // Detaching the scopes created by PreParser from the Scope chain must be done
+  // above (see ParseFunctionLiteral & AnalyzePartially).
+  if (!is_inner_function) function_scope->ResetAfterPreparsing();
   if (pre_parse_timer_ != NULL) {
     pre_parse_timer_->Stop();
   }