[parser] Parse tasks: save top-level function data.

BUG=v8:6093

Change-Id: I7268abd56769d4cbaefdaa901c532871837cc47e
Reviewed-on: https://chromium-review.googlesource.com/452340
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Wiktor Garbacz <wiktorg@google.com>
Cr-Commit-Position: refs/heads/master@{#43782}

src/flag-definitions.h

@@ -918,6 +918,10 @@ DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
 DEFINE_BOOL(trace_maps, false, "trace map creation")
 #endif
 
+// preparser.cc
+DEFINE_BOOL(use_parse_tasks, false, "use parse tasks")
+DEFINE_BOOL(trace_parse_tasks, false, "trace parse task creation")
+
 // parser.cc
 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
 DEFINE_BOOL(trace_parse, false, "trace parsing and preparsing")

src/parsing/parser-base.h

@@ -201,6 +201,7 @@ class ParserBase {
              RuntimeCallStats* runtime_call_stats,
              bool parsing_on_main_thread = true)
       : scope_(nullptr),
+        original_scope_(nullptr),
         function_state_(nullptr),
         extension_(extension),
         fni_(nullptr),
@@ -1391,6 +1392,7 @@ class ParserBase {
   // Parser base's protected field members.
 
   Scope* scope_;                   // Scope stack.
+  Scope* original_scope_;  // The top scope for the current parsing item.
   FunctionState* function_state_;  // Function state stack.
   v8::Extension* extension_;
   FuncNameInferrer* fni_;

src/parsing/parser.cc

@@ -507,7 +507,6 @@ Parser::Parser(ParseInfo* info)
                          true),
       scanner_(info->unicode_cache()),
       reusable_preparser_(nullptr),
-      original_scope_(nullptr),
       mode_(PARSE_EAGERLY),  // Lazy mode must be set explicitly.
       target_stack_(nullptr),
       compile_options_(info->compile_options()),
@@ -624,6 +623,12 @@ FunctionLiteral* Parser::ParseProgram(Isolate* isolate, ParseInfo* info) {
 
   {
     std::unique_ptr<Utf16CharacterStream> stream(ScannerStream::For(source));
+    if (FLAG_use_parse_tasks) {
+      // FIXME(wiktorg) make it useful for something
+      scanner_.Initialize(stream.get());
+      reusable_preparser()->PreParseProgram();
+      stream->Seek(0);
+    }
     scanner_.Initialize(stream.get());
     result = DoParseProgram(info);
   }

src/parsing/parser.h

@@ -1164,7 +1164,6 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
 
   Scanner scanner_;
   PreParser* reusable_preparser_;
-  Scope* original_scope_;  // for ES5 function declarations in sloppy eval
   Mode mode_;
 
   friend class ParserTarget;

src/parsing/preparse-data.cc

@@ -60,6 +60,24 @@ ScriptData* ParserLogger::GetScriptData() {
   return result;
 }
 
+PreParseData::FunctionData PreParseData::GetTopLevelFunctionData(
+    int start) const {
+  auto it = top_level_functions_data_.find(start);
+  if (it != top_level_functions_data_.end()) {
+    return it->second;
+  }
+  return FunctionData();
+}
+
+void PreParseData::AddTopLevelFunctionData(FunctionData&& data) {
+  DCHECK(data.is_valid());
+  top_level_functions_data_[data.start] = std::move(data);
+}
+
+void PreParseData::AddTopLevelFunctionData(const FunctionData& data) {
+  DCHECK(data.is_valid());
+  top_level_functions_data_[data.start] = data;
+}
 
 }  // namespace internal
 }  // namespace v8.

src/parsing/preparse-data.h

@@ -5,6 +5,8 @@
 #ifndef V8_PARSING_PREPARSE_DATA_H_
 #define V8_PARSING_PREPARSE_DATA_H_
 
+#include <unordered_map>
+
 #include "src/allocation.h"
 #include "src/base/hashmap.h"
 #include "src/collector.h"
@@ -111,6 +113,40 @@ class ParserLogger final {
 #endif
 };
 
+class PreParseData final {
+ public:
+  struct FunctionData {
+    int start;
+    int end;
+    int num_parameters;
+    int function_length;
+    bool has_duplicate_parameters;
+    int expected_property_count;
+    int num_inner_functions;
+
+    FunctionData() : start(-1), end(-1) {}
+
+    FunctionData(int start, int end, int num_parameters, int function_length,
+                 bool has_duplicate_parameters, int expected_property_count,
+                 int num_inner_functions)
+        : start(start),
+          end(end),
+          num_parameters(num_parameters),
+          function_length(function_length),
+          has_duplicate_parameters(has_duplicate_parameters),
+          expected_property_count(expected_property_count),
+          num_inner_functions(num_inner_functions) {}
+
+    bool is_valid() const { return start < end; }
+  };
+
+  FunctionData GetTopLevelFunctionData(int start) const;
+  void AddTopLevelFunctionData(FunctionData&& data);
+  void AddTopLevelFunctionData(const FunctionData& data);
+
+ private:
+  std::unordered_map<int, FunctionData> top_level_functions_data_;
+};
 
 }  // namespace internal
 }  // namespace v8.

src/parsing/preparser.cc

@@ -85,6 +85,35 @@ PreParserIdentifier PreParser::GetSymbol() const {
   return symbol;
 }
 
+PreParser::PreParseResult PreParser::PreParseProgram(bool is_module) {
+  DCHECK_NULL(scope_);
+  DeclarationScope* scope = NewScriptScope();
+#ifdef DEBUG
+  scope->set_is_being_lazily_parsed(true);
+#endif
+
+  // ModuleDeclarationInstantiation for Source Text Module Records creates a
+  // new Module Environment Record whose outer lexical environment record is
+  // the global scope.
+  if (is_module) scope = NewModuleScope(scope);
+
+  FunctionState top_scope(&function_state_, &scope_, scope);
+  original_scope_ = scope_;
+  bool ok = true;
+  int start_position = scanner()->peek_location().beg_pos;
+  parsing_module_ = is_module;
+  PreParserStatementList body;
+  ParseStatementList(body, Token::EOS, &ok);
+  original_scope_ = nullptr;
+  if (stack_overflow()) return kPreParseStackOverflow;
+  if (!ok) {
+    ReportUnexpectedToken(scanner()->current_token());
+  } else if (is_strict(this->scope()->language_mode())) {
+    CheckStrictOctalLiteral(start_position, scanner()->location().end_pos, &ok);
+  }
+  return kPreParseSuccess;
+}
+
 PreParser::PreParseResult PreParser::PreParseFunction(
     FunctionKind kind, DeclarationScope* function_scope, bool parsing_module,
     bool is_inner_function, bool may_abort, int* use_counts) {
@@ -233,12 +262,15 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
       runtime_call_stats_,
       counters[track_unresolved_variables_][parsing_on_main_thread_]);
 
+  bool is_top_level =
+      scope()->AllowsLazyParsingWithoutUnresolvedVariables(original_scope_);
+
   DeclarationScope* function_scope = NewFunctionScope(kind);
   function_scope->SetLanguageMode(language_mode);
   FunctionState function_state(&function_state_, &scope_, function_scope);
   DuplicateFinder duplicate_finder;
   ExpressionClassifier formals_classifier(this, &duplicate_finder);
-  GetNextFunctionLiteralId();
+  int func_id = GetNextFunctionLiteralId();
 
   Expect(Token::LPAREN, CHECK_OK);
   int start_position = scanner()->location().beg_pos;
@@ -280,6 +312,30 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
     CheckStrictOctalLiteral(start_position, end_position, CHECK_OK);
   }
 
+  if (FLAG_use_parse_tasks && is_top_level && preparse_data_) {
+    preparse_data_->AddTopLevelFunctionData(PreParseData::FunctionData(
+        start_position, end_position, formals.num_parameters(),
+        formals.function_length,
+        formals_classifier.is_valid_formal_parameter_list_without_duplicates(),
+        function_state_->expected_property_count(),
+        GetLastFunctionLiteralId() - func_id));
+    // TODO(wiktorg) spin-off a parse task
+    if (FLAG_trace_parse_tasks) {
+      PrintF("Saved function at %d to %d with:\n", start_position,
+             end_position);
+      PrintF("\t- %d params\n", formals.num_parameters());
+      PrintF("\t- %d function length\n", formals.function_length);
+      PrintF(
+          "\t- %s duplicate parameters\n",
+          formals_classifier.is_valid_formal_parameter_list_without_duplicates()
+              ? "NO"
+              : "SOME");
+      PrintF("\t- %d expected properties\n",
+             function_state_->expected_property_count());
+      PrintF("\t- %d inner-funcs\n", GetLastFunctionLiteralId() - func_id);
+    }
+  }
+
   if (FLAG_trace_preparse) {
     PrintF("  [%s]: %i-%i\n",
            track_unresolved_variables_ ? "Preparse resolution"

src/parsing/preparser.h

@@ -888,6 +888,7 @@ class PreParser : public ParserBase<PreParser> {
                               ast_value_factory, runtime_call_stats,
                               parsing_on_main_thread),
         use_counts_(nullptr),
+        preparse_data_(FLAG_use_parse_tasks ? new PreParseData() : nullptr),
         track_unresolved_variables_(false),
         pending_error_handler_(pending_error_handler) {}
 
@@ -899,33 +900,7 @@ class PreParser : public ParserBase<PreParser> {
   // success (even if parsing failed, the pre-parse data successfully
   // captured the syntax error), and false if a stack-overflow happened
   // during parsing.
-  PreParseResult PreParseProgram(bool is_module = false) {
-    DCHECK_NULL(scope_);
-    DeclarationScope* scope = NewScriptScope();
-#ifdef DEBUG
-    scope->set_is_being_lazily_parsed(true);
-#endif
-
-    // ModuleDeclarationInstantiation for Source Text Module Records creates a
-    // new Module Environment Record whose outer lexical environment record is
-    // the global scope.
-    if (is_module) scope = NewModuleScope(scope);
-
-    FunctionState top_scope(&function_state_, &scope_, scope);
-    bool ok = true;
-    int start_position = scanner()->peek_location().beg_pos;
-    parsing_module_ = is_module;
-    PreParserStatementList body;
-    ParseStatementList(body, Token::EOS, &ok);
-    if (stack_overflow()) return kPreParseStackOverflow;
-    if (!ok) {
-      ReportUnexpectedToken(scanner()->current_token());
-    } else if (is_strict(this->scope()->language_mode())) {
-      CheckStrictOctalLiteral(start_position, scanner()->location().end_pos,
-                              &ok);
-    }
-    return kPreParseSuccess;
-  }
+  PreParseResult PreParseProgram(bool is_module = false);
 
   // Parses a single function literal, from the opening parentheses before
   // parameters to the closing brace after the body.
@@ -941,6 +916,8 @@ class PreParser : public ParserBase<PreParser> {
                                   bool track_unresolved_variables,
                                   bool may_abort, int* use_counts);
 
+  const PreParseData* preparse_data() const { return preparse_data_.get(); }
+
  private:
   // These types form an algebra over syntactic categories that is just
   // rich enough to let us recognize and propagate the constructs that
@@ -1679,6 +1656,7 @@ class PreParser : public ParserBase<PreParser> {
   // Preparser's private field members.
 
   int* use_counts_;
+  std::unique_ptr<PreParseData> preparse_data_;
   bool track_unresolved_variables_;
   PreParserLogger log_;
   PendingCompilationErrorHandler* pending_error_handler_;