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

src/parsing/parser.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/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 911 matching lines @@
   fni_->PushEnclosingName(raw_name);
 
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
 
   // Place holder for the result.
   FunctionLiteral* result = nullptr;
 
   {
     // 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);
     bool ok = true;
 
     if (info->is_arrow()) {
       bool is_async = allow_harmony_async_await() && info->is_async();
       if (is_async) {
         DCHECK(!scanner()->HasAnyLineTerminatorAfterNext());
         if (!Check(Token::ASYNC)) {
@@ skipping 1988 matching lines @@
                               FunctionKind::kAsyncFunction, pos, type,
                               language_mode(), CHECK_OK);
 }
 
 Parser::LazyParsingResult Parser::SkipLazyFunctionBody(
     int* materialized_literal_count, int* expected_property_count,
     bool is_inner_function, bool may_abort, bool* ok) {
   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.
   if (!is_inner_function && consume_cached_parse_data() &&
       !cached_parse_data_->rejected()) {
     // If we have cached data, we use it to skip parsing the function body. The
     // data contains the information we need to construct the lazy function.
     FunctionEntry entry =
         cached_parse_data_->GetFunctionEntry(function_block_pos);
     // Check that cached data is valid. If not, mark it as invalid (the embedder
@@ skipping 12 matching lines @@
       if (entry.calls_eval()) scope->RecordEvalCall();
       return kLazyParsingComplete;
     }
     cached_parse_data_->Reject();
   }
   // With no cached data, we partially parse the function, without building an
   // AST. This gathers the data needed to build a lazy function.
   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);
     return kLazyParsingAborted;
   }
   if (result == PreParser::kPreParseStackOverflow) {
     // Propagate stack overflow.
     set_stack_overflow();
     *ok = false;
     return kLazyParsingComplete;
@@ skipping 481 matching lines @@
     SET_ALLOW(harmony_restrictive_declarations);
     SET_ALLOW(harmony_async_await);
     SET_ALLOW(harmony_trailing_commas);
     SET_ALLOW(harmony_class_fields);
 #undef SET_ALLOW
   }
   // Aborting inner function preparsing would leave scopes in an inconsistent
   // 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();
   }
   return result;
 }
 
 Expression* Parser::InstallHomeObject(Expression* function_literal,
                                       Expression* home_object) {
   Block* do_block = factory()->NewBlock(nullptr, 1, false, kNoSourcePosition);
   Variable* result_var =
@@ skipping 2103 matching lines @@
 
   return final_loop;
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8