Pre-cache PLY yacc parse table and use optimized mode (45% build time improvement)

Source/bindings/generated_bindings.gyp

 #
 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 101 matching lines @@
       '<(SHARED_INTERMEDIATE_DIR)/ServiceWorkerGlobalScopeConstructors.idl',
     ],
 
 
     # Python source
     'jinja_module_files': [
       # jinja2/__init__.py contains version string, so sufficient for package
       '<(DEPTH)/third_party/jinja2/__init__.py',
       '<(DEPTH)/third_party/markupsafe/__init__.py',  # jinja2 dep
     ],
-    'idl_compiler_files': [
-      'scripts/idl_compiler.py',
+    'idl_lexer_parser_files': [
       # PLY (Python Lex-Yacc)
       '<(DEPTH)/third_party/ply/lex.py',
       '<(DEPTH)/third_party/ply/yacc.py',
       # Web IDL lexer/parser (base parser)
       '<(DEPTH)/tools/idl_parser/idl_lexer.py',
       '<(DEPTH)/tools/idl_parser/idl_node.py',
       '<(DEPTH)/tools/idl_parser/idl_parser.py',
       # Blink IDL lexer/parser/constructor
       'scripts/blink_idl_lexer.py',
       'scripts/blink_idl_parser.py',
+    ],
+    'idl_compiler_files': [
+      'scripts/idl_compiler.py',
+      # Blink IDL front end (ex-lexer/parser)
       'scripts/idl_definitions.py',
       'scripts/idl_reader.py',
       'scripts/idl_validator.py',
       'scripts/interface_dependency_resolver.py',
       # V8 code generator
       'scripts/code_generator_v8.py',
       'scripts/v8_attributes.py',
       'scripts/v8_callback_interface.py',
       'scripts/v8_globals.py',
       'scripts/v8_interface.py',
@@ skipping 130 matching lines @@
         '<(SHARED_INTERMEDIATE_DIR)/blink/InterfacesInfo.pickle',
         '--event-names-file',
         '<(SHARED_INTERMEDIATE_DIR)/blink/EventInterfaces.in',
         '<@(write_file_only_if_changed)',
       ],
       'message': 'Generating list of Event interfaces',
       }]
   },
 ################################################################################
   {
+    # A separate pre-caching step is *not required* to use parse table caching
+    # in PLY, as the cache is concurrency-safe.
+    # However, pre-caching ensures that all compiler processes use the cached
+    # file (hence maximizing speed), instead of early processes building the
+    # table themselves (as it's not yet been written by the time they start).
+    'target_name': 'cached_yacc_tables',
+    'type': 'none',
+    'actions': [{
+      'action_name': 'cache_yacc_tables',
+      'inputs': [
+        '<@(idl_lexer_parser_files)',
+      ],
+      'outputs': [
+        '<(bindings_output_dir)/parsetab.pickle',

[haraken, 2014/03/05 06:18:04]

parsed_yacc_table.pickle ?

[Nils Barth (inactive), 2014/03/05 06:28:05]

"parsetab.pickle" is the PLY standard name.
(Similarly, PLY uses "parsetab.py" for the module.)

+      ],
+      'action': [
+        'python',
+        'scripts/blink_idl_parser.py',
+        '<(bindings_output_dir)',
+      ],
+      'message': 'Caching PLY yacc parse tables',
+    }],
+  },
+################################################################################
+  {
     # A separate pre-caching step is *required* to use bytecode caching in
     # Jinja (which improves speed significantly), as the bytecode cache is
     # not concurrency-safe on write; details in code_generator_v8.py.
     'target_name': 'cached_jinja_templates',
     'type': 'none',
     'actions': [{
       'action_name': 'cache_jinja_templates',
       'inputs': [
         '<@(jinja_module_files)',
         'scripts/code_generator_v8.py',
@@ skipping 13 matching lines @@
   },
 ################################################################################
   {
     'target_name': 'individual_generated_bindings',
     'type': 'none',
     # The 'binding' rule generates .h files, so mark as hard_dependency, per:
     # https://code.google.com/p/gyp/wiki/InputFormatReference#Linking_Dependencies
     'hard_dependency': 1,
     'dependencies': [
       'interfaces_info',
+      'cached_yacc_tables',
       'cached_jinja_templates',
       '../core/core_generated.gyp:generated_testing_idls',
     ],
     'sources': [
       '<@(interface_idl_files)',
     ],
     'rules': [{
       'rule_name': 'binding',
       'extension': 'idl',
       'msvs_external_rule': 1,
       'inputs': [
+        '<@(idl_lexer_parser_files)',  # to be explicit (covered by parsetab)
         '<@(idl_compiler_files)',
+        '<(bindings_output_dir)/parsetab.pickle',
         '<(bindings_output_dir)/cached_jinja_templates.stamp',
         'IDLExtendedAttributes.txt',
         # If the dependency structure or public interface info (e.g.,
         # [ImplementedAs]) changes, we rebuild all files, since we're not
         # computing dependencies file-by-file in the build.
         # This data is generally stable.
         '<(SHARED_INTERMEDIATE_DIR)/blink/InterfacesInfo.pickle',
         # Further, if any dependency (partial interface or implemented
         # interface) changes, rebuild everything, since every IDL potentially
         # depends on them, because we're not computing dependencies
@@ skipping 55 matching lines @@
     'type': 'none',
     'dependencies': [
       'aggregate_generated_bindings',
       'event_interfaces',
       'individual_generated_bindings',
     ],
   },
 ################################################################################
   ],  # targets
 }