1 #!/usr/bin/env python 2 3 """ 4 Deduce types for usage observations. 5 6 Copyright (C) 2014, 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 details. 17 18 You should have received a copy of the GNU General Public License along with 19 this program. If not, see <http://www.gnu.org/licenses/>. 20 """ 21 22 from common import first, get_assigned_attributes, \ 23 get_attrname_from_location, get_attrnames, \ 24 get_invoked_attributes, get_name_path, init_item, \ 25 sorted_output, CommonOutput 26 from encoders import encode_access_location, encode_constrained, \ 27 encode_instruction, encode_location, encode_usage, \ 28 get_kinds, test_label_for_kind, test_label_for_type 29 from errors import DeduceError 30 from os.path import join 31 from referencing import combine_types, is_single_class_type, separate_types, \ 32 Reference 33 34 class Deducer(CommonOutput): 35 36 "Deduce types in a program." 37 38 root_class_type = "__builtins__.object" 39 40 def __init__(self, importer, output): 41 42 """ 43 Initialise an instance using the given 'importer' that will perform 44 deductions on the program information, writing the results to the given 45 'output' directory. 46 """ 47 48 self.importer = importer 49 self.output = output 50 51 # Descendants of classes. 52 53 self.descendants = {} 54 self.init_descendants() 55 self.init_special_attributes() 56 57 # Map locations to usage in order to determine specific types. 58 59 self.location_index = {} 60 61 # Map access locations to definition locations. 62 63 self.access_index = {} 64 65 # Map aliases to accesses that define them. 66 67 self.alias_index = {} 68 69 # Map constant accesses to redefined accesses. 70 71 self.const_accesses = {} 72 self.const_accesses_rev = {} 73 74 # Map usage observations to assigned attributes. 75 76 self.assigned_attrs = {} 77 78 # Map usage observations to objects. 79 80 self.attr_class_types = {} 81 self.attr_instance_types = {} 82 self.attr_module_types = {} 83 84 # All known attribute names. 85 86 self.all_attrnames = set() 87 88 # Modified attributes from usage observations. 89 90 self.modified_attributes = {} 91 92 # Accesses that are assignments or invocations. 93 94 self.reference_assignments = set() 95 self.reference_invocations = {} 96 self.reference_invocations_unsuitable = {} 97 98 # Map locations to types, constrained indicators and attributes. 99 100 self.accessor_class_types = {} 101 self.accessor_instance_types = {} 102 self.accessor_module_types = {} 103 self.provider_class_types = {} 104 self.provider_instance_types = {} 105 self.provider_module_types = {} 106 self.accessor_constrained = set() 107 self.access_constrained = set() 108 self.referenced_attrs = {} 109 self.referenced_objects = {} 110 111 # Details of access operations. 112 113 self.access_plans = {} 114 115 # Specific attribute access information. 116 117 self.access_instructions = {} 118 self.accessor_kinds = {} 119 120 # Accumulated information about accessors and providers. 121 122 self.accessor_general_class_types = {} 123 self.accessor_general_instance_types = {} 124 self.accessor_general_module_types = {} 125 self.accessor_all_types = {} 126 self.accessor_all_general_types = {} 127 self.provider_all_types = {} 128 self.accessor_guard_tests = {} 129 130 # Accumulated information about accessed attributes and 131 # access/attribute-specific accessor tests. 132 133 self.reference_all_attrs = {} 134 self.reference_all_providers = {} 135 self.reference_all_provider_kinds = {} 136 self.reference_all_accessor_types = {} 137 self.reference_all_accessor_general_types = {} 138 self.reference_test_types = {} 139 self.reference_test_accessor_type = {} 140 141 # The processing workflow itself. 142 143 self.init_usage_index() 144 self.init_attr_type_indexes() 145 self.init_combined_attribute_index() 146 self.init_accessors() 147 self.init_accesses() 148 self.init_aliases() 149 self.modify_mutated_attributes() 150 self.identify_references() 151 self.classify_accessors() 152 self.classify_accesses() 153 self.initialise_access_plans() 154 self.initialise_access_instructions() 155 self.identify_dependencies() 156 157 def to_output(self): 158 159 "Write the output files using deduction information." 160 161 self.check_output() 162 163 self.write_mutations() 164 self.write_accessors() 165 self.write_accesses() 166 self.write_access_plans() 167 168 def write_mutations(self): 169 170 """ 171 Write mutation-related output in the following format: 172 173 qualified name " " original object type 174 175 Object type can be "<class>", "<function>" or "<var>". 176 """ 177 178 f = open(join(self.output, "mutations"), "w") 179 try: 180 attrs = self.modified_attributes.items() 181 attrs.sort() 182 183 for attr, value in attrs: 184 print >>f, attr, value 185 finally: 186 f.close() 187 188 def write_accessors(self): 189 190 """ 191 Write reference-related output in the following format for types: 192 193 location " " ( "constrained" | "deduced" ) " " attribute type " " most general type names " " number of specific types 194 195 Note that multiple lines can be given for each location, one for each 196 attribute type. 197 198 Locations have the following format: 199 200 qualified name of scope "." local name ":" name version 201 202 The attribute type can be "<class>", "<instance>", "<module>" or "<>", 203 where the latter indicates an absence of suitable references. 204 205 Type names indicate the type providing the attributes, being either a 206 class or module qualified name. 207 208 ---- 209 210 A summary of accessor types is formatted as follows: 211 212 location " " ( "constrained" | "deduced" ) " " ( "specific" | "common" | "unguarded" ) " " most general type names " " number of specific types 213 214 This summary groups all attribute types (class, instance, module) into a 215 single line in order to determine the complexity of identifying an 216 accessor. 217 218 ---- 219 220 References that cannot be supported by any types are written to a 221 warnings file in the following format: 222 223 location 224 225 ---- 226 227 For each location where a guard would be asserted to guarantee the 228 nature of an object, the following format is employed: 229 230 location " " ( "specific" | "common" ) " " object kind " " object types 231 232 Object kind can be "<class>", "<instance>" or "<module>". 233 """ 234 235 f_type_summary = open(join(self.output, "type_summary"), "w") 236 f_types = open(join(self.output, "types"), "w") 237 f_warnings = open(join(self.output, "type_warnings"), "w") 238 f_guards = open(join(self.output, "guards"), "w") 239 240 try: 241 locations = self.accessor_class_types.keys() 242 locations.sort() 243 244 for location in locations: 245 constrained = location in self.accessor_constrained 246 247 # Accessor information. 248 249 class_types = self.accessor_class_types[location] 250 instance_types = self.accessor_instance_types[location] 251 module_types = self.accessor_module_types[location] 252 253 general_class_types = self.accessor_general_class_types[location] 254 general_instance_types = self.accessor_general_instance_types[location] 255 general_module_types = self.accessor_general_module_types[location] 256 257 all_types = self.accessor_all_types[location] 258 all_general_types = self.accessor_all_general_types[location] 259 260 if class_types: 261 print >>f_types, encode_location(location), encode_constrained(constrained), "<class>", \ 262 sorted_output(general_class_types), len(class_types) 263 264 if instance_types: 265 print >>f_types, encode_location(location), encode_constrained(constrained), "<instance>", \ 266 sorted_output(general_instance_types), len(instance_types) 267 268 if module_types: 269 print >>f_types, encode_location(location), encode_constrained(constrained), "<module>", \ 270 sorted_output(general_module_types), len(module_types) 271 272 if not all_types: 273 print >>f_types, encode_location(location), "deduced", "<>", 0 274 attrnames = list(self.location_index[location]) 275 attrnames.sort() 276 print >>f_warnings, encode_location(location), "; ".join(map(encode_usage, attrnames)) 277 278 guard_test = self.accessor_guard_tests.get(location) 279 if guard_test: 280 guard_test_type, guard_test_arg = guard_test 281 282 # Write specific type guard details. 283 284 if guard_test and guard_test_type == "specific": 285 print >>f_guards, encode_location(location), "-".join(guard_test), \ 286 first(get_kinds(all_types)), \ 287 sorted_output(all_types) 288 289 # Write common type guard details. 290 291 elif guard_test and guard_test_type == "common": 292 print >>f_guards, encode_location(location), "-".join(guard_test), \ 293 first(get_kinds(all_general_types)), \ 294 sorted_output(all_general_types) 295 296 print >>f_type_summary, encode_location(location), encode_constrained(constrained), \ 297 guard_test and "-".join(guard_test) or "unguarded", sorted_output(all_general_types), len(all_types) 298 299 finally: 300 f_type_summary.close() 301 f_types.close() 302 f_warnings.close() 303 f_guards.close() 304 305 def write_accesses(self): 306 307 """ 308 Specific attribute output is produced in the following format: 309 310 location " " ( "constrained" | "deduced" ) " " attribute type " " attribute references 311 312 Note that multiple lines can be given for each location and attribute 313 name, one for each attribute type. 314 315 Locations have the following format: 316 317 qualified name of scope "." local name " " attribute name ":" access number 318 319 The attribute type can be "<class>", "<instance>", "<module>" or "<>", 320 where the latter indicates an absence of suitable references. 321 322 Attribute references have the following format: 323 324 object type ":" qualified name 325 326 Object type can be "<class>", "<function>" or "<var>". 327 328 ---- 329 330 A summary of attributes is formatted as follows: 331 332 location " " attribute name " " ( "constrained" | "deduced" ) " " test " " attribute references 333 334 This summary groups all attribute types (class, instance, module) into a 335 single line in order to determine the complexity of each access. 336 337 Tests can be "validate", "specific", "untested", "guarded-validate" or "guarded-specific". 338 339 ---- 340 341 For each access where a test would be asserted to guarantee the 342 nature of an attribute, the following formats are employed: 343 344 location " " attribute name " " "validate" 345 location " " attribute name " " "specific" " " attribute type " " object type 346 347 ---- 348 349 References that cannot be supported by any types are written to a 350 warnings file in the following format: 351 352 location 353 """ 354 355 f_attr_summary = open(join(self.output, "attribute_summary"), "w") 356 f_attrs = open(join(self.output, "attributes"), "w") 357 f_tests = open(join(self.output, "tests"), "w") 358 f_warnings = open(join(self.output, "attribute_warnings"), "w") 359 f_unsuitable = open(join(self.output, "invocation_warnings"), "w") 360 361 try: 362 locations = self.referenced_attrs.keys() 363 locations.sort() 364 365 for location in locations: 366 constrained = location in self.access_constrained 367 368 # Attribute information, both name-based and anonymous. 369 370 referenced_attrs = self.referenced_attrs[location] 371 372 if referenced_attrs: 373 attrname = get_attrname_from_location(location) 374 375 all_accessed_attrs = self.reference_all_attrs[location] 376 377 for attrtype, attrs in self.get_referenced_attrs(location): 378 print >>f_attrs, encode_access_location(location), encode_constrained(constrained), attrtype, sorted_output(attrs) 379 380 test_type = self.reference_test_types.get(location) 381 382 # Write the need to test at run time. 383 384 if test_type[0] == "validate": 385 print >>f_tests, encode_access_location(location), "-".join(test_type) 386 387 # Write any type checks for anonymous accesses. 388 389 elif test_type and self.reference_test_accessor_type.get(location): 390 print >>f_tests, encode_access_location(location), "-".join(test_type), \ 391 sorted_output(all_accessed_attrs), \ 392 self.reference_test_accessor_type[location] 393 394 print >>f_attr_summary, encode_access_location(location), encode_constrained(constrained), \ 395 test_type and "-".join(test_type) or "untested", sorted_output(all_accessed_attrs) 396 397 # Write details of potentially unsuitable invocation 398 # occurrences. 399 400 unsuitable = self.reference_invocations_unsuitable.get(location) 401 if unsuitable: 402 unsuitable = map(str, unsuitable) 403 unsuitable.sort() 404 print >>f_unsuitable, encode_access_location(location), ", ".join(unsuitable) 405 406 else: 407 print >>f_warnings, encode_access_location(location) 408 409 finally: 410 f_attr_summary.close() 411 f_attrs.close() 412 f_tests.close() 413 f_warnings.close() 414 f_unsuitable.close() 415 416 def write_access_plans(self): 417 418 """ 419 Write access and instruction plans. 420 421 Each attribute access is written out as a plan of the following form: 422 423 location " " name " " test " " test type " " base " " traversed attributes 424 " " traversal access modes " " attributes to traverse 425 " " context " " context test " " first access method 426 " " final access method " " static attribute " " accessor kinds 427 428 Locations have the following format: 429 430 qualified name of scope "." local name ":" name version 431 432 Traversal access modes are either "class" (obtain accessor class to 433 access attribute) or "object" (obtain attribute directly from accessor). 434 """ 435 436 f_attrs = open(join(self.output, "attribute_plans"), "w") 437 438 try: 439 locations = self.access_plans.keys() 440 locations.sort() 441 442 for location in locations: 443 name, test, test_type, base, \ 444 traversed, traversal_modes, attrnames, \ 445 context, context_test, \ 446 first_method, final_method, \ 447 attr, accessor_kinds = self.access_plans[location] 448 449 print >>f_attrs, encode_access_location(location), \ 450 name or "{}", \ 451 test and "-".join(test) or "{}", \ 452 test_type or "{}", \ 453 base or "{}", \ 454 ".".join(traversed) or "{}", \ 455 ".".join(traversal_modes) or "{}", \ 456 ".".join(attrnames) or "{}", \ 457 context, context_test, \ 458 first_method, final_method, attr or "{}", \ 459 ",".join(accessor_kinds) 460 461 finally: 462 f_attrs.close() 463 464 f = open(join(self.output, "instruction_plans"), "w") 465 try: 466 access_instructions = self.access_instructions.items() 467 access_instructions.sort() 468 469 for location, instructions in access_instructions: 470 print >>f, encode_access_location(location), "..." 471 for instruction in instructions: 472 print >>f, encode_instruction(instruction) 473 print >>f 474 475 finally: 476 f.close() 477 478 def classify_accessors(self): 479 480 "For each program location, classify accessors." 481 482 # Where instance and module types are defined, class types are also 483 # defined. See: init_definition_details 484 485 locations = self.accessor_class_types.keys() 486 487 for location in locations: 488 constrained = location in self.accessor_constrained 489 490 # Provider information. 491 492 class_types = self.provider_class_types[location] 493 instance_types = self.provider_instance_types[location] 494 module_types = self.provider_module_types[location] 495 496 # Collect specific and general type information. 497 498 self.provider_all_types[location] = \ 499 combine_types(class_types, instance_types, module_types) 500 501 # Accessor information. 502 503 class_types = self.accessor_class_types[location] 504 self.accessor_general_class_types[location] = \ 505 general_class_types = self.get_most_general_class_types(class_types) 506 507 instance_types = self.accessor_instance_types[location] 508 self.accessor_general_instance_types[location] = \ 509 general_instance_types = self.get_most_general_class_types(instance_types) 510 511 module_types = self.accessor_module_types[location] 512 self.accessor_general_module_types[location] = \ 513 general_module_types = self.get_most_general_module_types(module_types) 514 515 # Collect specific and general type information. 516 517 self.accessor_all_types[location] = all_types = \ 518 combine_types(class_types, instance_types, module_types) 519 520 self.accessor_all_general_types[location] = all_general_types = \ 521 combine_types(general_class_types, general_instance_types, general_module_types) 522 523 # Record guard information. 524 525 if not constrained: 526 527 # Record specific type guard details. 528 529 if len(all_types) == 1: 530 self.accessor_guard_tests[location] = ("specific", test_label_for_type(first(all_types))) 531 elif is_single_class_type(all_types): 532 self.accessor_guard_tests[location] = ("specific", "object") 533 534 # Record common type guard details. 535 536 elif len(all_general_types) == 1: 537 self.accessor_guard_tests[location] = ("common", test_label_for_type(first(all_types))) 538 elif is_single_class_type(all_general_types): 539 self.accessor_guard_tests[location] = ("common", "object") 540 541 # Otherwise, no convenient guard can be defined. 542 543 def classify_accesses(self): 544 545 "For each program location, classify accesses." 546 547 # Attribute accesses use potentially different locations to those of 548 # accessors. 549 550 locations = self.referenced_attrs.keys() 551 552 for location in locations: 553 constrained = location in self.access_constrained 554 555 # Combine type information from all accessors supplying the access. 556 557 accessor_locations = self.get_accessors_for_access(location) 558 559 all_provider_types = set() 560 all_accessor_types = set() 561 all_accessor_general_types = set() 562 563 for accessor_location in accessor_locations: 564 565 # Obtain the provider types for guard-related attribute access 566 # checks. 567 568 all_provider_types.update(self.provider_all_types.get(accessor_location)) 569 570 # Obtain the accessor guard types (specific and general). 571 572 all_accessor_types.update(self.accessor_all_types.get(accessor_location)) 573 all_accessor_general_types.update(self.accessor_all_general_types.get(accessor_location)) 574 575 # Obtain basic properties of the types involved in the access. 576 577 single_accessor_type = len(all_accessor_types) == 1 578 single_accessor_class_type = is_single_class_type(all_accessor_types) 579 single_accessor_general_type = len(all_accessor_general_types) == 1 580 single_accessor_general_class_type = is_single_class_type(all_accessor_general_types) 581 582 # Determine whether the attribute access is guarded or not. 583 584 guarded = ( 585 single_accessor_type or single_accessor_class_type or 586 single_accessor_general_type or single_accessor_general_class_type 587 ) 588 589 if guarded: 590 (guard_class_types, guard_instance_types, guard_module_types, 591 _function_types, _var_types) = separate_types(all_provider_types) 592 593 self.reference_all_accessor_types[location] = all_accessor_types 594 self.reference_all_accessor_general_types[location] = all_accessor_general_types 595 596 # Attribute information, both name-based and anonymous. 597 598 referenced_attrs = self.referenced_attrs[location] 599 600 if not referenced_attrs: 601 raise DeduceError("In %s, access via %s to attribute %s (occurrence %d) cannot be identified." % location) 602 603 # Record attribute information for each name used on the 604 # accessor. 605 606 attrname = get_attrname_from_location(location) 607 608 self.reference_all_attrs[location] = all_accessed_attrs = [] 609 self.reference_all_providers[location] = all_providers = [] 610 self.reference_all_provider_kinds[location] = all_provider_kinds = set() 611 612 # Obtain provider and attribute details for this kind of 613 # object. 614 615 for attrtype, object_type, attr in referenced_attrs: 616 all_accessed_attrs.append(attr) 617 all_providers.append(object_type) 618 all_provider_kinds.add(attrtype) 619 620 # Obtain reference and provider information as sets for the 621 # operations below, retaining the list forms for use with 622 # instruction plan preparation. 623 624 all_accessed_attrs = set(all_accessed_attrs) 625 all_providers = set(all_providers) 626 all_general_providers = self.get_most_general_types(all_providers) 627 628 # Determine which attributes would be provided by the 629 # accessor types upheld by a guard. 630 631 if guarded: 632 guard_attrs = set() 633 634 for _attrtype, object_type, attr in \ 635 self._identify_reference_attribute(location, attrname, guard_class_types, guard_instance_types, guard_module_types): 636 637 guard_attrs.add(attr) 638 else: 639 guard_attrs = None 640 641 # Constrained accesses guarantee the nature of the accessor. 642 # However, there may still be many types involved. 643 644 if constrained: 645 if single_accessor_type: 646 self.reference_test_types[location] = ("constrained", "specific", test_label_for_type(first(all_accessor_types))) 647 elif single_accessor_class_type: 648 self.reference_test_types[location] = ("constrained", "specific", "object") 649 elif single_accessor_general_type: 650 self.reference_test_types[location] = ("constrained", "common", test_label_for_type(first(all_accessor_general_types))) 651 elif single_accessor_general_class_type: 652 self.reference_test_types[location] = ("constrained", "common", "object") 653 else: 654 self.reference_test_types[location] = ("constrained", "many") 655 656 # Suitably guarded accesses, where the nature of the 657 # accessor can be guaranteed, do not require the attribute 658 # involved to be validated. Otherwise, for unguarded 659 # accesses, access-level tests are required. 660 661 elif guarded and all_accessed_attrs.issubset(guard_attrs): 662 if single_accessor_type: 663 self.reference_test_types[location] = ("guarded", "specific", test_label_for_type(first(all_accessor_types))) 664 elif single_accessor_class_type: 665 self.reference_test_types[location] = ("guarded", "specific", "object") 666 elif single_accessor_general_type: 667 self.reference_test_types[location] = ("guarded", "common", test_label_for_type(first(all_accessor_general_types))) 668 elif single_accessor_general_class_type: 669 self.reference_test_types[location] = ("guarded", "common", "object") 670 671 # Record the need to test the type of anonymous and 672 # unconstrained accessors. 673 674 elif len(all_providers) == 1: 675 provider = first(all_providers) 676 if provider != self.root_class_type: 677 all_accessor_kinds = set(get_kinds(all_accessor_types)) 678 if len(all_accessor_kinds) == 1: 679 test_type = ("test", "specific", test_label_for_kind(first(all_accessor_kinds))) 680 else: 681 test_type = ("test", "specific", "object") 682 self.reference_test_types[location] = test_type 683 self.reference_test_accessor_type[location] = provider 684 685 elif len(all_general_providers) == 1: 686 provider = first(all_general_providers) 687 if provider != self.root_class_type: 688 all_accessor_kinds = set(get_kinds(all_accessor_general_types)) 689 if len(all_accessor_kinds) == 1: 690 test_type = ("test", "common", test_label_for_kind(first(all_accessor_kinds))) 691 else: 692 test_type = ("test", "common", "object") 693 self.reference_test_types[location] = test_type 694 self.reference_test_accessor_type[location] = provider 695 696 # Record the need to test the identity of the attribute. 697 698 else: 699 self.reference_test_types[location] = ("validate",) 700 701 def initialise_access_plans(self): 702 703 "Define attribute access plans." 704 705 for location in self.referenced_attrs.keys(): 706 original_location = self.const_accesses_rev.get(location) 707 self.access_plans[original_location or location] = self.get_access_plan(location) 708 709 def identify_dependencies(self): 710 711 "Introduce more module dependencies to the importer." 712 713 for location, referenced_attrs in self.referenced_attrs.items(): 714 path, name, attrnames, version = location 715 716 # Identify module-level paths. 717 718 if self.importer.modules.has_key(path): 719 module_name = path 720 721 # Identify the module containing other paths. 722 723 else: 724 ref = self.importer.identify(path) 725 for objpath in ref.ancestors(): 726 if self.importer.modules.has_key(objpath): 727 module_name = objpath 728 break 729 else: 730 raise DeduceError("Cannot find module for path %s." % path) 731 732 # Identify references providing dependencies. 733 734 for attrtype, objtype, attr in referenced_attrs: 735 self.importer.add_dependency(path, attr.get_origin()) 736 737 def get_referenced_attrs(self, location): 738 739 """ 740 Return attributes referenced at the given access 'location' by the given 741 'attrname' as a list of (attribute type, attribute set) tuples. 742 """ 743 744 d = {} 745 for attrtype, objtype, attr in self.referenced_attrs[location]: 746 init_item(d, attrtype, set) 747 d[attrtype].add(attr.unaliased()) 748 l = d.items() 749 l.sort() # class, module, instance 750 return l 751 752 # Initialisation methods. 753 754 def init_descendants(self): 755 756 "Identify descendants of each class." 757 758 for name in self.importer.classes.keys(): 759 self.get_descendants_for_class(name) 760 761 def get_descendants_for_class(self, name): 762 763 """ 764 Use subclass information to deduce the descendants for the class of the 765 given 'name'. 766 """ 767 768 if not self.descendants.has_key(name): 769 descendants = set() 770 771 for subclass in self.importer.subclasses[name]: 772 descendants.update(self.get_descendants_for_class(subclass)) 773 descendants.add(subclass) 774 775 self.descendants[name] = descendants 776 777 return self.descendants[name] 778 779 def init_special_attributes(self): 780 781 "Add special attributes to the classes for inheritance-related tests." 782 783 all_class_attrs = self.importer.all_class_attrs 784 785 for name, descendants in self.descendants.items(): 786 for descendant in descendants: 787 all_class_attrs[descendant]["#%s" % name] = name 788 789 for name in all_class_attrs.keys(): 790 all_class_attrs[name]["#%s" % name] = name 791 792 def init_usage_index(self): 793 794 """ 795 Create indexes for module and function attribute usage and for anonymous 796 accesses. 797 """ 798 799 for module in self.importer.get_modules(): 800 for path, assignments in module.attr_usage.items(): 801 self.add_usage(assignments, path) 802 803 for location, all_attrnames in self.importer.all_attr_accesses.items(): 804 for attrnames in all_attrnames: 805 attrname = get_attrnames(attrnames)[-1] 806 access_location = (location, None, attrnames, 0) 807 self.add_usage_term(access_location, ((attrname, False, False),)) 808 809 def add_usage(self, assignments, path): 810 811 """ 812 Collect usage from the given 'assignments', adding 'path' details to 813 each record if specified. Add the usage to an index mapping to location 814 information, as well as to an index mapping locations to usages. 815 """ 816 817 for name, versions in assignments.items(): 818 for i, usages in enumerate(versions): 819 location = (path, name, None, i) 820 821 for usage in usages: 822 self.add_usage_term(location, usage) 823 824 def add_usage_term(self, location, usage): 825 826 """ 827 For 'location' and using 'usage' as a description of usage, record 828 in the usage index a mapping from the usage to 'location', and record in 829 the location index a mapping from 'location' to the usage. 830 """ 831 832 init_item(self.location_index, location, set) 833 self.location_index[location].add(usage) 834 835 def init_accessors(self): 836 837 "Create indexes for module and function accessor information." 838 839 for module in self.importer.get_modules(): 840 for path, all_accesses in module.attr_accessors.items(): 841 self.add_accessors(all_accesses, path) 842 843 def add_accessors(self, all_accesses, path): 844 845 """ 846 For attribute accesses described by the mapping of 'all_accesses' from 847 name details to accessor details, record the locations of the accessors 848 for each access. 849 """ 850 851 # Get details for each access combining the given name and attribute. 852 853 for (name, attrnames), accesses in all_accesses.items(): 854 855 # Obtain the usage details using the access information. 856 857 for access_number, versions in enumerate(accesses): 858 access_location = (path, name, attrnames, access_number) 859 locations = [] 860 861 for version in versions: 862 location = (path, name, None, version) 863 locations.append(location) 864 865 self.access_index[access_location] = locations 866 867 def get_accessors_for_access(self, access_location): 868 869 "Find a definition providing accessor details, if necessary." 870 871 try: 872 return self.access_index[access_location] 873 except KeyError: 874 return [access_location] 875 876 def init_accesses(self): 877 878 """ 879 Check that attributes used in accesses are actually defined on some 880 object. This can be overlooked if unknown attributes are employed in 881 attribute chains. 882 883 Initialise collections for accesses involving assignments. 884 """ 885 886 # For each scope, obtain access details. 887 888 for path, all_accesses in self.importer.all_attr_access_modifiers.items(): 889 890 # For each combination of name and attribute names, obtain 891 # applicable modifiers. 892 893 for (name, attrname_str), modifiers in all_accesses.items(): 894 895 # For each access, determine the name versions affected by 896 # assignments. 897 898 for access_number, (assignment, invocation) in enumerate(modifiers): 899 900 if name: 901 access_location = (path, name, attrname_str, access_number) 902 else: 903 access_location = (path, None, attrname_str, 0) 904 905 # Plain name accesses do not employ attributes and are 906 # ignored. 907 908 if not attrname_str: 909 continue 910 911 attrnames = get_attrnames(attrname_str) 912 913 # Check the attribute names. 914 915 for attrname in attrnames: 916 if not attrname in self.all_attrnames: 917 raise DeduceError("In %s, attribute %s is not defined in the program." % (path, attrname)) 918 919 # Now only process assignments and invocations. 920 921 if invocation: 922 self.reference_invocations[access_location] = invocation 923 continue 924 elif not assignment: 925 continue 926 927 # Associate assignments with usage. 928 929 self.reference_assignments.add(access_location) 930 931 # Assignment occurs for the only attribute. 932 933 if len(attrnames) == 1: 934 accessor_locations = self.get_accessors_for_access(access_location) 935 936 for location in accessor_locations: 937 for usage in self.location_index[location]: 938 init_item(self.assigned_attrs, usage, set) 939 self.assigned_attrs[usage].add((path, name, attrnames[0])) 940 941 # Assignment occurs for the final attribute. 942 943 else: 944 usage = ((attrnames[-1], False, False),) 945 init_item(self.assigned_attrs, usage, set) 946 self.assigned_attrs[usage].add((path, name, attrnames[-1])) 947 948 def init_aliases(self): 949 950 "Expand aliases so that alias-based accesses can be resolved." 951 952 # Get aliased names with details of their accesses. 953 954 for (path, name), all_aliases in self.importer.all_aliased_names.items(): 955 956 # For each version of the name, obtain the access location. 957 958 for version, (original_path, original_name, attrnames, access_number) in all_aliases.items(): 959 accessor_location = (path, name, None, version) 960 access_location = (original_path, original_name, attrnames, access_number) 961 init_item(self.alias_index, accessor_location, list) 962 self.alias_index[accessor_location].append(access_location) 963 964 # Get aliases in terms of non-aliases and accesses. 965 966 for accessor_location, access_locations in self.alias_index.items(): 967 self.update_aliases(accessor_location, access_locations) 968 969 def update_aliases(self, accessor_location, access_locations, visited=None): 970 971 """ 972 Update the given 'accessor_location' defining an alias, update 973 'access_locations' to refer to non-aliases, following name references 974 via the access index. 975 976 If 'visited' is specified, it contains a set of accessor locations (and 977 thus keys to the alias index) that are currently being defined. 978 """ 979 980 if visited is None: 981 visited = set() 982 983 updated_locations = set() 984 985 for access_location in access_locations: 986 (path, original_name, attrnames, access_number) = access_location 987 988 # Where an alias refers to a name access, obtain the original name 989 # version details. 990 991 if attrnames is None: 992 993 # For each name version, attempt to determine any accesses that 994 # initialise the name. 995 996 for name_accessor_location in self.access_index[access_location]: 997 998 # Already-visited aliases do not contribute details. 999 1000 if name_accessor_location in visited: 1001 continue 1002 1003 visited.add(name_accessor_location) 1004 1005 name_access_locations = self.alias_index.get(name_accessor_location) 1006 if name_access_locations: 1007 updated_locations.update(self.update_aliases(name_accessor_location, name_access_locations, visited)) 1008 else: 1009 updated_locations.add(name_accessor_location) 1010 1011 # Otherwise, record the access details. 1012 1013 else: 1014 updated_locations.add(access_location) 1015 1016 self.alias_index[accessor_location] = updated_locations 1017 return updated_locations 1018 1019 # Attribute mutation for types. 1020 1021 def modify_mutated_attributes(self): 1022 1023 "Identify known, mutated attributes and change their state." 1024 1025 # Usage-based accesses. 1026 1027 for usage, all_attrnames in self.assigned_attrs.items(): 1028 if not usage: 1029 continue 1030 1031 for path, name, attrname in all_attrnames: 1032 class_types = self.get_class_types_for_usage(usage) 1033 only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types) 1034 module_types = self.get_module_types_for_usage(usage) 1035 1036 # Detect self usage within methods in order to narrow the scope 1037 # of the mutation. 1038 1039 t = name == "self" and self.constrain_self_reference(path, class_types, only_instance_types) 1040 if t: 1041 class_types, only_instance_types, module_types, constrained = t 1042 objects = set(class_types).union(only_instance_types).union(module_types) 1043 1044 self.mutate_attribute(objects, attrname) 1045 1046 def mutate_attribute(self, objects, attrname): 1047 1048 "Mutate static 'objects' with the given 'attrname'." 1049 1050 for name in objects: 1051 attr = "%s.%s" % (name, attrname) 1052 value = self.importer.get_object(attr) 1053 1054 # If the value is None, the attribute is 1055 # inherited and need not be set explicitly on 1056 # the class concerned. 1057 1058 if value: 1059 self.modified_attributes[attr] = value 1060 self.importer.set_object(attr, value.as_var()) 1061 1062 # Simplification of types. 1063 1064 def get_most_general_types(self, types): 1065 1066 "Return the most general types for the given 'types'." 1067 1068 module_types = set() 1069 class_types = set() 1070 1071 for type in types: 1072 ref = self.importer.identify(type) 1073 if ref.has_kind("<module>"): 1074 module_types.add(type) 1075 else: 1076 class_types.add(type) 1077 1078 types = set(self.get_most_general_module_types(module_types)) 1079 types.update(self.get_most_general_class_types(class_types)) 1080 return types 1081 1082 def get_most_general_class_types(self, class_types): 1083 1084 "Return the most general types for the given 'class_types'." 1085 1086 class_types = set(class_types) 1087 to_remove = set() 1088 1089 for class_type in class_types: 1090 for base in self.importer.classes[class_type]: 1091 base = base.get_origin() 1092 descendants = self.descendants[base] 1093 if base in class_types and descendants.issubset(class_types): 1094 to_remove.update(descendants) 1095 1096 class_types.difference_update(to_remove) 1097 return class_types 1098 1099 def get_most_general_module_types(self, module_types): 1100 1101 "Return the most general type for the given 'module_types'." 1102 1103 # Where all modules are provided, an object would provide the same 1104 # attributes. 1105 1106 if len(module_types) == len(self.importer.modules): 1107 return [self.root_class_type] 1108 else: 1109 return module_types 1110 1111 # More efficient usage-to-type indexing and retrieval. 1112 1113 def init_attr_type_indexes(self): 1114 1115 "Identify the types that can support each attribute name." 1116 1117 self._init_attr_type_index(self.attr_class_types, self.importer.all_class_attrs) 1118 self._init_attr_type_index(self.attr_instance_types, self.importer.all_instance_attrs, True) 1119 self._init_attr_type_index(self.attr_instance_types, self.importer.all_combined_attrs, False) 1120 self._init_attr_type_index(self.attr_module_types, self.importer.all_module_attrs) 1121 1122 def _init_attr_type_index(self, attr_types, attrs, assignment=None): 1123 1124 """ 1125 Initialise the 'attr_types' attribute-to-types mapping using the given 1126 'attrs' type-to-attributes mapping. 1127 """ 1128 1129 for name, attrnames in attrs.items(): 1130 for attrname in attrnames: 1131 1132 # Permit general access for certain kinds of object. 1133 1134 if assignment is None: 1135 init_item(attr_types, (attrname, False), set) 1136 init_item(attr_types, (attrname, True), set) 1137 attr_types[(attrname, False)].add(name) 1138 attr_types[(attrname, True)].add(name) 1139 1140 # Restrict attribute assignment for instances. 1141 1142 else: 1143 init_item(attr_types, (attrname, assignment), set) 1144 attr_types[(attrname, assignment)].add(name) 1145 1146 def get_class_types_for_usage(self, usage): 1147 1148 "Return names of classes supporting the given 'usage'." 1149 1150 return self._get_types_for_usage(usage, self.attr_class_types, self.importer.all_class_attrs) 1151 1152 def get_instance_types_for_usage(self, usage): 1153 1154 """ 1155 Return names of classes whose instances support the given 'usage' 1156 (as either class or instance attributes). 1157 """ 1158 1159 return self._get_types_for_usage(usage, self.attr_instance_types, self.importer.all_combined_attrs) 1160 1161 def get_module_types_for_usage(self, usage): 1162 1163 "Return names of modules supporting the given 'usage'." 1164 1165 return self._get_types_for_usage(usage, self.attr_module_types, self.importer.all_module_attrs) 1166 1167 def _get_types_for_usage(self, usage, attr_types, attrs): 1168 1169 """ 1170 For the given 'usage' representing attribute usage, return types 1171 recorded in the 'attr_types' attribute-to-types mapping that support 1172 such usage, with the given 'attrs' type-to-attributes mapping used to 1173 quickly assess whether a type supports all of the stated attributes. 1174 """ 1175 1176 # Where no attributes are used, any type would be acceptable. 1177 1178 if not usage: 1179 return attrs.keys() 1180 1181 keys = [] 1182 for attrname, invocation, assignment in usage: 1183 keys.append((attrname, assignment)) 1184 1185 # Obtain types supporting the first (attribute name, assignment) key... 1186 1187 types = set(attr_types.get(keys[0]) or []) 1188 1189 for key in keys[1:]: 1190 1191 # Record types that support all of the other attributes as well. 1192 1193 types.intersection_update(attr_types.get(key) or []) 1194 1195 return types 1196 1197 def init_combined_attribute_index(self): 1198 1199 "Initialise a combined index for the detection of invalid attributes." 1200 1201 self.all_attrnames = set() 1202 for attrs in (self.importer.all_combined_attrs, self.importer.all_module_attrs): 1203 for name, attrnames in attrs.items(): 1204 self.all_attrnames.update(attrnames) 1205 1206 # Reference identification. 1207 1208 def identify_references(self): 1209 1210 "Identify references using usage and name reference information." 1211 1212 # Names with associated attribute usage. 1213 1214 for location, usages in self.location_index.items(): 1215 1216 # Obtain attribute usage associated with a name, deducing the nature 1217 # of the name. Obtain types only for branches involving attribute 1218 # usage. (In the absence of usage, any type could be involved, but 1219 # then no accesses exist to require knowledge of the type.) 1220 1221 have_usage = False 1222 have_no_usage_branch = False 1223 1224 for usage in usages: 1225 if not usage: 1226 have_no_usage_branch = True 1227 continue 1228 elif not have_usage: 1229 self.init_definition_details(location) 1230 have_usage = True 1231 self.record_types_for_usage(location, usage) 1232 1233 # Where some usage occurs, but where branches without usage also 1234 # occur, record the types for those branches anyway. 1235 1236 if have_usage and have_no_usage_branch: 1237 self.init_definition_details(location) 1238 self.record_types_for_usage(location, None) 1239 1240 # Specific name-based attribute accesses. 1241 1242 alias_accesses = set() 1243 1244 for access_location, accessor_locations in self.access_index.items(): 1245 self.record_types_for_access(access_location, accessor_locations, alias_accesses) 1246 1247 # Anonymous references with attribute chains. 1248 1249 for location, accesses in self.importer.all_attr_accesses.items(): 1250 1251 # Get distinct attribute names. 1252 1253 all_attrnames = set() 1254 1255 for attrnames in accesses: 1256 all_attrnames.update(get_attrnames(attrnames)) 1257 1258 # Get attribute and accessor details for each attribute name. 1259 1260 for attrname in all_attrnames: 1261 access_location = (location, None, attrname, 0) 1262 self.record_types_for_attribute(access_location, attrname) 1263 1264 # References via constant/identified objects. 1265 1266 for location, name_accesses in self.importer.all_const_accesses.items(): 1267 1268 # A mapping from the original name and attributes to resolved access 1269 # details. 1270 1271 for original_access, access in name_accesses.items(): 1272 original_name, original_attrnames = original_access 1273 objpath, ref, attrnames = access 1274 1275 # Build an accessor combining the name and attribute names used. 1276 1277 original_accessor = tuple([original_name] + original_attrnames.split(".")) 1278 1279 # Direct accesses to attributes. 1280 1281 if not attrnames: 1282 1283 # Build a descriptive location based on the original 1284 # details, exposing the final attribute name. 1285 1286 oa, attrname = original_accessor[:-1], original_accessor[-1] 1287 oa = ".".join(oa) 1288 1289 access_location = (location, oa, attrname, 0) 1290 accessor_location = (location, oa, None, 0) 1291 self.access_index[access_location] = [accessor_location] 1292 1293 self.init_access_details(access_location) 1294 self.init_definition_details(accessor_location) 1295 1296 # Obtain a reference for the accessor in order to properly 1297 # determine its type. 1298 1299 if ref.get_kind() != "<instance>": 1300 objpath = ref.get_origin() 1301 1302 objpath = objpath.rsplit(".", 1)[0] 1303 1304 # Where the object name conflicts with the module 1305 # providing it, obtain the module details. 1306 1307 if objpath in self.importer.modules: 1308 accessor = Reference("<module>", objpath) 1309 else: 1310 accessor = self.importer.get_object(objpath) 1311 1312 self.referenced_attrs[access_location] = [(accessor.get_kind(), accessor.get_origin(), ref)] 1313 self.access_constrained.add(access_location) 1314 1315 class_types, instance_types, module_types = accessor.get_types() 1316 self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True) 1317 1318 else: 1319 1320 # Build a descriptive location based on the original 1321 # details, employing the first remaining attribute name. 1322 1323 l = get_attrnames(attrnames) 1324 attrname = l[0] 1325 1326 oa = original_accessor[:-len(l)] 1327 oa = ".".join(oa) 1328 1329 access_location = (location, oa, attrnames, 0) 1330 accessor_location = (location, oa, None, 0) 1331 self.access_index[access_location] = [accessor_location] 1332 1333 self.init_access_details(access_location) 1334 self.init_definition_details(accessor_location) 1335 1336 class_types, instance_types, module_types = ref.get_types() 1337 1338 self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, True) 1339 self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True) 1340 1341 # Define mappings between the original and access locations 1342 # so that translation can work from the source details. 1343 1344 original_location = (location, original_name, original_attrnames, 0) 1345 1346 if original_location != access_location: 1347 self.const_accesses[original_location] = access_location 1348 self.const_accesses_rev[access_location] = original_location 1349 1350 # Aliased name definitions. All aliases with usage will have been 1351 # defined, but they may be refined according to referenced accesses. 1352 1353 for accessor_location in self.alias_index.keys(): 1354 self.record_types_for_alias(accessor_location) 1355 1356 # Update accesses employing aliases. 1357 1358 for access_location in alias_accesses: 1359 self.record_types_for_access(access_location, self.access_index[access_location]) 1360 1361 def constrain_types(self, path, class_types, instance_types, module_types): 1362 1363 """ 1364 Using the given 'path' to an object, constrain the given 'class_types', 1365 'instance_types' and 'module_types'. 1366 1367 Return the class, instance, module types plus whether the types are 1368 constrained to a specific kind of type. 1369 """ 1370 1371 ref = self.importer.identify(path) 1372 if ref: 1373 1374 # Constrain usage suggestions using the identified object. 1375 1376 if ref.has_kind("<class>"): 1377 return ( 1378 set(class_types).intersection([ref.get_origin()]), [], [], True 1379 ) 1380 elif ref.has_kind("<module>"): 1381 return ( 1382 [], [], set(module_types).intersection([ref.get_origin()]), True 1383 ) 1384 1385 return class_types, instance_types, module_types, False 1386 1387 def get_target_types(self, location, usage): 1388 1389 """ 1390 Return the class, instance and module types constrained for the name at 1391 the given 'location' exhibiting the given 'usage'. Whether the types 1392 have been constrained using contextual information is also indicated, 1393 plus whether the types have been constrained to a specific kind of type. 1394 """ 1395 1396 unit_path, name, attrnames, version = location 1397 have_assignments = get_assigned_attributes(usage) 1398 1399 # Detect any initialised name for the location. 1400 1401 if name: 1402 ref = self.get_initialised_name(location) 1403 if ref: 1404 (class_types, only_instance_types, module_types, 1405 _function_types, _var_types) = separate_types([ref]) 1406 return class_types, only_instance_types, module_types, True, have_assignments 1407 1408 # Retrieve the recorded types for the usage. 1409 1410 class_types = self.get_class_types_for_usage(usage) 1411 only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types) 1412 module_types = self.get_module_types_for_usage(usage) 1413 1414 # Merge usage deductions with observations to obtain reference types 1415 # for names involved with attribute accesses. 1416 1417 if not name: 1418 return class_types, only_instance_types, module_types, False, have_assignments 1419 1420 # Obtain references to known objects. 1421 1422 path = get_name_path(unit_path, name) 1423 1424 class_types, only_instance_types, module_types, constrained_specific = \ 1425 self.constrain_types(path, class_types, only_instance_types, module_types) 1426 1427 if constrained_specific: 1428 return class_types, only_instance_types, module_types, constrained_specific, \ 1429 constrained_specific or have_assignments 1430 1431 # Constrain "self" references. 1432 1433 if name == "self": 1434 1435 # Test for the class of the method in the deduced types. 1436 1437 class_name = self.in_method(unit_path) 1438 1439 if class_name and class_name not in class_types and class_name not in only_instance_types: 1440 raise DeduceError("In %s, usage {%s} is not directly supported by class %s or its instances." % 1441 (unit_path, encode_usage(usage), class_name)) 1442 1443 # Constrain the types to the class's hierarchy. 1444 1445 t = self.constrain_self_reference(unit_path, class_types, only_instance_types) 1446 if t: 1447 class_types, only_instance_types, module_types, constrained = t 1448 return class_types, only_instance_types, module_types, constrained, have_assignments 1449 1450 return class_types, only_instance_types, module_types, False, have_assignments 1451 1452 def constrain_self_reference(self, unit_path, class_types, only_instance_types): 1453 1454 """ 1455 Where the name "self" appears in a method, attempt to constrain the 1456 classes involved. 1457 1458 Return the class, instance, module types plus whether the types are 1459 constrained. 1460 """ 1461 1462 class_name = self.in_method(unit_path) 1463 1464 if not class_name: 1465 return None 1466 1467 classes = set([class_name]) 1468 classes.update(self.get_descendants_for_class(class_name)) 1469 1470 # Note that only instances will be expected for these references but 1471 # either classes or instances may provide the attributes. 1472 1473 return ( 1474 set(class_types).intersection(classes), 1475 set(only_instance_types).intersection(classes), 1476 [], True 1477 ) 1478 1479 def in_method(self, path): 1480 1481 "Return whether 'path' refers to a method." 1482 1483 class_name, method_name = path.rsplit(".", 1) 1484 return class_name != "__builtins__.core.type" and self.importer.classes.has_key(class_name) and class_name 1485 1486 def init_reference_details(self, location): 1487 1488 "Initialise reference-related details for 'location'." 1489 1490 self.init_definition_details(location) 1491 self.init_access_details(location) 1492 1493 def init_definition_details(self, location): 1494 1495 "Initialise name definition details for 'location'." 1496 1497 self.accessor_class_types[location] = set() 1498 self.accessor_instance_types[location] = set() 1499 self.accessor_module_types[location] = set() 1500 self.provider_class_types[location] = set() 1501 self.provider_instance_types[location] = set() 1502 self.provider_module_types[location] = set() 1503 1504 def init_access_details(self, location): 1505 1506 "Initialise access details at 'location'." 1507 1508 self.referenced_attrs[location] = {} 1509 1510 def record_types_for_access(self, access_location, accessor_locations, alias_accesses=None): 1511 1512 """ 1513 Define types for the 'access_location' associated with the given 1514 'accessor_locations'. 1515 """ 1516 1517 attrname = get_attrname_from_location(access_location) 1518 if not attrname: 1519 return 1520 1521 # Collect all suggested types for the accessors. Accesses may 1522 # require accessors from of a subset of the complete set of types. 1523 1524 class_types = set() 1525 module_types = set() 1526 instance_types = set() 1527 1528 constrained = True 1529 1530 for location in accessor_locations: 1531 1532 # Remember accesses employing aliases. 1533 1534 if alias_accesses is not None and self.alias_index.has_key(location): 1535 alias_accesses.add(access_location) 1536 1537 # Use the type information deduced for names from above. 1538 1539 if self.accessor_class_types.has_key(location): 1540 class_types.update(self.accessor_class_types[location]) 1541 module_types.update(self.accessor_module_types[location]) 1542 instance_types.update(self.accessor_instance_types[location]) 1543 1544 # Where accesses are associated with assignments but where no 1545 # attribute usage observations have caused such an association, 1546 # the attribute name is considered by itself. 1547 1548 else: 1549 self.init_definition_details(location) 1550 self.record_types_for_usage(location, [(attrname, False, False)]) 1551 1552 constrained = location in self.accessor_constrained and constrained 1553 1554 self.init_access_details(access_location) 1555 self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, constrained) 1556 1557 def record_types_for_usage(self, accessor_location, usage): 1558 1559 """ 1560 Record types for the given 'accessor_location' according to the given 1561 'usage' observations which may be None to indicate an absence of usage. 1562 """ 1563 1564 (class_types, 1565 instance_types, 1566 module_types, 1567 constrained, 1568 constrained_specific) = self.get_target_types(accessor_location, usage) 1569 1570 invocations = get_invoked_attributes(usage) 1571 1572 self.record_reference_types(accessor_location, class_types, instance_types, 1573 module_types, constrained, constrained_specific, invocations) 1574 1575 def record_types_for_attribute(self, access_location, attrname): 1576 1577 """ 1578 Record types for the 'access_location' employing only the given 1579 'attrname' for type deduction. 1580 """ 1581 1582 (class_types, 1583 only_instance_types, 1584 module_types) = self.get_types_for_attribute(attrname) 1585 1586 self.init_reference_details(access_location) 1587 1588 self.identify_reference_attributes(access_location, attrname, class_types, only_instance_types, module_types, False) 1589 self.record_reference_types(access_location, class_types, only_instance_types, module_types, False) 1590 1591 def get_types_for_attribute(self, attrname): 1592 1593 "Return class, instance-only and module types supporting 'attrname'." 1594 1595 usage = ((attrname, False, False),) 1596 1597 class_types = self.get_class_types_for_usage(usage) 1598 only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types) 1599 module_types = self.get_module_types_for_usage(usage) 1600 1601 return class_types, only_instance_types, module_types 1602 1603 def record_types_for_alias(self, accessor_location): 1604 1605 """ 1606 Define types for the 'accessor_location' not having associated usage. 1607 """ 1608 1609 have_access = self.provider_class_types.has_key(accessor_location) 1610 1611 # With an access, attempt to narrow the existing selection of provider 1612 # types. Invocations attempt to find return value information, with 1613 # instance return values also yielding class providers (since attributes 1614 # on instances could be provided by classes). 1615 1616 if have_access: 1617 provider_class_types = self.provider_class_types[accessor_location] 1618 provider_instance_types = self.provider_instance_types[accessor_location] 1619 provider_module_types = self.provider_module_types[accessor_location] 1620 1621 # Find details for any corresponding access. 1622 1623 all_class_types = set() 1624 all_instance_types = set() 1625 all_module_types = set() 1626 1627 for access_location in self.alias_index[accessor_location]: 1628 location, name, attrnames, access_number = access_location 1629 invocation = self.reference_invocations.get(access_location) 1630 1631 # Alias references an attribute access. 1632 1633 if attrnames: 1634 1635 # Obtain references and attribute types for the access. 1636 1637 attrs = self.get_references_for_access(access_location) 1638 attrs = self.convert_invocation_providers(attrs, invocation) 1639 1640 (class_types, instance_types, module_types, function_types, 1641 var_types) = separate_types(attrs) 1642 1643 # Where non-accessor types are found, do not attempt to refine 1644 # the defined accessor types. 1645 1646 if function_types or var_types: 1647 return 1648 1649 # Invocations converting class accessors to instances do not 1650 # change the nature of class providers. 1651 1652 class_types = set(provider_class_types).intersection(class_types) 1653 instance_types = set(provider_instance_types).intersection(instance_types) 1654 module_types = set(provider_module_types).intersection(module_types) 1655 1656 # Alias references a name, not an access. 1657 1658 else: 1659 # Attempt to refine the types using initialised names. 1660 1661 attr = self.get_initialised_name(access_location) 1662 if attr: 1663 attrs = self.convert_invocation_providers([attr], invocation) 1664 1665 (class_types, instance_types, module_types, function_types, 1666 var_types) = separate_types(attrs) 1667 1668 # Where no further information is found, do not attempt to 1669 # refine the defined accessor types. 1670 1671 else: 1672 return 1673 1674 all_class_types.update(class_types) 1675 all_instance_types.update(instance_types) 1676 all_module_types.update(module_types) 1677 1678 # Record refined type details for the alias as an accessor. 1679 1680 self.init_definition_details(accessor_location) 1681 self.record_reference_types(accessor_location, all_class_types, all_instance_types, all_module_types, False) 1682 1683 # Without an access, attempt to identify references for the alias. 1684 # Invocations convert classes to instances and also attempt to find 1685 # return value information. 1686 1687 else: 1688 refs = set() 1689 1690 for access_location in self.alias_index[accessor_location]: 1691 1692 # Obtain any redefined constant access location. 1693 1694 if self.const_accesses.has_key(access_location): 1695 access_location = self.const_accesses[access_location] 1696 1697 location, name, attrnames, access_number = access_location 1698 invocation = self.reference_invocations.get(access_location) 1699 1700 attrnames = attrnames and attrnames.split(".") 1701 remaining = attrnames and len(attrnames) > 1 1702 1703 # Alias has remaining attributes: reference details do not 1704 # correspond to the accessor; the remaining attributes would 1705 # need to be traversed first. 1706 1707 if remaining: 1708 return 1709 1710 # Alias references an attribute access. 1711 1712 attrname = attrnames and attrnames[0] 1713 1714 if attrname: 1715 1716 # Obtain references and attribute types for the access. 1717 1718 attrs = self.get_references_for_access(access_location) 1719 attrs = self.convert_invocations(attrs, invocation) 1720 refs.update(attrs) 1721 1722 # Alias references a name, not an access. 1723 1724 else: 1725 1726 # Obtain initialiser information. 1727 1728 attr = self.get_initialised_name(access_location) 1729 if attr: 1730 refs.update(self.convert_invocations([attr], invocation)) 1731 1732 # Obtain provider information. 1733 1734 elif self.provider_class_types.has_key(access_location): 1735 class_types = self.provider_class_types[access_location] 1736 instance_types = self.provider_instance_types[access_location] 1737 module_types = self.provider_module_types[access_location] 1738 1739 refs.update(combine_types(class_types, instance_types, module_types)) 1740 1741 # Record reference details for the alias separately from accessors. 1742 1743 self.referenced_objects[accessor_location] = refs 1744 1745 def get_references_for_access(self, access_location): 1746 1747 "Return the references identified for 'access_location'." 1748 1749 attrs = [] 1750 for attrtype, object_type, attr in self.referenced_attrs[access_location]: 1751 attrs.append(attr) 1752 return attrs 1753 1754 def convert_invocation_providers(self, refs, invocation): 1755 1756 """ 1757 Convert 'refs' to providers corresponding to the results of invoking 1758 each of the given references, if 'invocation' is set to a true value. 1759 """ 1760 1761 if not invocation: 1762 return refs 1763 1764 providers = set() 1765 1766 for ref in refs: 1767 ref = self.convert_invocation_provider(ref) 1768 if ref.has_kind("<instance>"): 1769 providers.add(Reference("<class>", ref.get_origin())) 1770 providers.add(ref) 1771 1772 return providers 1773 1774 def convert_invocation_provider(self, ref): 1775 1776 "Convert 'ref' to a provider appropriate to its invocation result." 1777 1778 if ref and ref.has_kind("<class>"): 1779 return ref 1780 1781 return Reference("<var>") 1782 1783 def convert_invocations(self, refs, invocation): 1784 1785 """ 1786 Convert 'refs' to invocation results if 'invocation' is set to a true 1787 value. 1788 """ 1789 1790 return invocation and map(self.convert_invocation, refs) or refs 1791 1792 def convert_invocation(self, ref): 1793 1794 "Convert 'ref' to its invocation result." 1795 1796 if ref and ref.has_kind("<class>"): 1797 return ref.instance_of() 1798 1799 return Reference("<var>") 1800 1801 def get_initialised_name(self, access_location): 1802 1803 """ 1804 Return references for any initialised names at 'access_location', or 1805 None if no such references exist. 1806 """ 1807 1808 path, name, attrnames, version = access_location 1809 1810 # Use initialiser information, if available. 1811 1812 refs = self.importer.all_initialised_names.get((path, name)) 1813 if refs and refs.has_key(version): 1814 return refs[version] 1815 else: 1816 return None 1817 1818 def record_reference_types(self, location, class_types, instance_types, 1819 module_types, constrained, constrained_specific=False, invocations=None): 1820 1821 """ 1822 Associate attribute provider types with the given 'location', consisting 1823 of the given 'class_types', 'instance_types' and 'module_types'. 1824 1825 If 'constrained' is indicated, the constrained nature of the accessor is 1826 recorded for the location. 1827 1828 If 'constrained_specific' is indicated using a true value, instance types 1829 will not be added to class types to permit access via instances at the 1830 given location. This is only useful where a specific accessor is known 1831 to be a class. 1832 1833 If 'invocations' is given, the given attribute names indicate those 1834 which are involved in invocations. Such invocations, if involving 1835 functions, will employ those functions as bound methods and will 1836 therefore not support classes as accessors, only instances of such 1837 classes. 1838 1839 Note that the specified types only indicate the provider types for 1840 attributes, whereas the recorded accessor types indicate the possible 1841 types of the actual objects used to access attributes. 1842 """ 1843 1844 # Update the type details for the location. 1845 1846 self.provider_class_types[location].update(class_types) 1847 self.provider_instance_types[location].update(instance_types) 1848 self.provider_module_types[location].update(module_types) 1849 1850 # Class types support classes and instances as accessors. 1851 # Instance-only and module types support only their own kinds as 1852 # accessors. 1853 1854 path, name, version, attrnames = location 1855 1856 if invocations: 1857 class_only_types = self.filter_for_invocations(class_types, invocations) 1858 else: 1859 class_only_types = class_types 1860 1861 # However, the nature of accessors can be further determined. 1862 # Any self variable may only refer to an instance. 1863 1864 if name != "self" or not self.in_method(path): 1865 self.accessor_class_types[location].update(class_only_types) 1866 1867 if not constrained_specific: 1868 self.accessor_instance_types[location].update(class_types) 1869 1870 self.accessor_instance_types[location].update(instance_types) 1871 1872 if name != "self" or not self.in_method(path): 1873 self.accessor_module_types[location].update(module_types) 1874 1875 if constrained: 1876 self.accessor_constrained.add(location) 1877 1878 def filter_for_invocations(self, class_types, attrnames): 1879 1880 """ 1881 From the given 'class_types', identify methods for the given 1882 'attrnames' that are being invoked, returning a filtered collection of 1883 class types. 1884 1885 This method may be used to remove class types from consideration where 1886 their attributes are methods that are directly invoked: method 1887 invocations must involve instance accessors. 1888 """ 1889 1890 to_filter = set() 1891 1892 for class_type in class_types: 1893 for attrname in attrnames: 1894 1895 # Attempt to obtain a class attribute of the given name. This 1896 # may return an attribute provided by an ancestor class. 1897 1898 ref = self.importer.get_class_attribute(class_type, attrname) 1899 parent_class = ref and ref.parent() 1900 1901 # If such an attribute is a method and would be available on 1902 # the given class, record the class for filtering. 1903 1904 if ref and ref.has_kind("<function>") and ( 1905 parent_class == class_type or 1906 class_type in self.descendants[parent_class]): 1907 1908 to_filter.add(class_type) 1909 break 1910 1911 return set(class_types).difference(to_filter) 1912 1913 def identify_reference_attributes(self, location, attrname, class_types, instance_types, module_types, constrained): 1914 1915 """ 1916 Identify reference attributes, associating them with the given 1917 'location', identifying the given 'attrname', employing the given 1918 'class_types', 'instance_types' and 'module_types'. 1919 1920 If 'constrained' is indicated, the constrained nature of the access is 1921 recorded for the location. 1922 """ 1923 1924 # Record the referenced objects. 1925 1926 self.referenced_attrs[location] = \ 1927 self._identify_reference_attribute(location, attrname, class_types, instance_types, module_types) 1928 1929 if constrained: 1930 self.access_constrained.add(location) 1931 1932 def _identify_reference_attribute(self, location, attrname, class_types, instance_types, module_types): 1933 1934 """ 1935 Identify the reference attribute at the given access 'location', using 1936 the given 'attrname', and employing the given 'class_types', 1937 'instance_types' and 'module_types'. 1938 """ 1939 1940 attrs = set() 1941 1942 # The class types expose class attributes either directly or via 1943 # instances. 1944 1945 for object_type in class_types: 1946 ref = self.importer.get_class_attribute(object_type, attrname) 1947 if ref and self.is_compatible_callable(location, object_type, ref): 1948 attrs.add(("<class>", object_type, ref)) 1949 1950 # Add any distinct instance attributes that would be provided 1951 # by instances also providing indirect class attribute access. 1952 1953 for ref in self.importer.get_instance_attributes(object_type, attrname): 1954 if self.is_compatible_callable(location, object_type, ref): 1955 attrs.add(("<instance>", object_type, ref)) 1956 1957 # The instance-only types expose instance attributes, but although 1958 # classes are excluded as potential accessors (since they do not provide 1959 # the instance attributes), the class types may still provide some 1960 # attributes. 1961 1962 for object_type in instance_types: 1963 instance_attrs = self.importer.get_instance_attributes(object_type, attrname) 1964 1965 if instance_attrs: 1966 for ref in instance_attrs: 1967 if self.is_compatible_callable(location, object_type, ref): 1968 attrs.add(("<instance>", object_type, ref)) 1969 else: 1970 ref = self.importer.get_class_attribute(object_type, attrname) 1971 if ref and self.is_compatible_callable(location, object_type, ref): 1972 attrs.add(("<class>", object_type, ref)) 1973 1974 # Module types expose module attributes for module accessors. 1975 1976 for object_type in module_types: 1977 ref = self.importer.get_module_attribute(object_type, attrname) 1978 if ref and self.is_compatible_callable(location, object_type, ref): 1979 attrs.add(("<module>", object_type, ref)) 1980 1981 return attrs 1982 1983 def is_compatible_callable(self, location, object_type, ref): 1984 1985 """ 1986 Return whether any invocation at 'location' involving an attribute of 1987 'object_type' identified by 'ref' is compatible with any arguments used. 1988 """ 1989 1990 invocation = self.reference_invocations.get(location) 1991 if invocation is None: 1992 return True 1993 1994 objpath = ref.get_origin() 1995 if not objpath: 1996 return True 1997 1998 parameters = self.importer.function_parameters.get(objpath) 1999 if not parameters: 2000 return True 2001 2002 defaults = self.importer.function_defaults.get(objpath) 2003 arguments, keywords = invocation 2004 names = set(parameters) 2005 2006 # Determine whether the specified arguments are 2007 # compatible with the callable signature. 2008 2009 if arguments >= len(parameters) - len(defaults) and \ 2010 arguments <= len(parameters) and \ 2011 names.issuperset(keywords): 2012 2013 return True 2014 else: 2015 init_item(self.reference_invocations_unsuitable, location, set) 2016 self.reference_invocations_unsuitable[location].add(ref) 2017 return False 2018 2019 # Attribute access plan formulation. 2020 2021 class_tests = ( 2022 ("guarded", "specific", "type"), 2023 ("guarded", "common", "type"), 2024 ("test", "specific", "type"), 2025 ("test", "common", "type"), 2026 ) 2027 2028 def get_access_plan(self, location): 2029 2030 """ 2031 Return details of the access at the given 'location'. The details are as 2032 follows: 2033 2034 * the initial accessor (from which accesses will be performed if no 2035 computed static accessor is found) 2036 * details of any test required on the initial accessor 2037 * details of any type employed by the test 2038 * any static accessor (from which accesses will be performed in 2039 preference to the initial accessor) 2040 * attributes needing to be traversed from the base that yield 2041 unambiguous objects 2042 * access modes for each of the unambiguously-traversed attributes 2043 * remaining attributes needing to be tested and traversed 2044 * details of the context 2045 * any test to apply to the context 2046 * the method of obtaining the first attribute 2047 * the method of obtaining the final attribute 2048 * any static final attribute 2049 * the kinds of objects providing the final attribute 2050 """ 2051 2052 const_access = self.const_accesses_rev.get(location) 2053 2054 path, name, attrnames, version = location 2055 remaining = attrnames.split(".") 2056 attrname = remaining[0] 2057 2058 # Obtain reference, provider and provider kind information. 2059 2060 attrs = self.reference_all_attrs[location] 2061 provider_types = self.reference_all_providers[location] 2062 provider_kinds = self.reference_all_provider_kinds[location] 2063 2064 # Obtain accessor type and kind information. 2065 2066 accessor_types = self.reference_all_accessor_types[location] 2067 accessor_general_types = self.reference_all_accessor_general_types[location] 2068 accessor_kinds = get_kinds(accessor_general_types) 2069 2070 # Determine any guard or test requirements. 2071 2072 constrained = location in self.access_constrained 2073 test = self.reference_test_types[location] 2074 test_type = self.reference_test_accessor_type.get(location) 2075 2076 # Determine the accessor and provider properties. 2077 2078 class_accessor = "<class>" in accessor_kinds 2079 module_accessor = "<module>" in accessor_kinds 2080 instance_accessor = "<instance>" in accessor_kinds 2081 provided_by_class = "<class>" in provider_kinds 2082 provided_by_instance = "<instance>" in provider_kinds 2083 2084 # Determine how attributes may be accessed relative to the accessor. 2085 2086 object_relative = class_accessor or module_accessor or provided_by_instance 2087 class_relative = instance_accessor and provided_by_class 2088 2089 # Identify the last static attribute for context acquisition. 2090 2091 base = None 2092 dynamic_base = None 2093 2094 # Constant accesses have static providers. 2095 2096 if const_access: 2097 base = len(provider_types) == 1 and first(provider_types) 2098 2099 # Name-based accesses. 2100 2101 elif name: 2102 ref = self.importer.identify("%s.%s" % (path, name)) 2103 2104 # Constant accessors are static. 2105 2106 if ref and ref.static(): 2107 base = ref.get_origin() 2108 2109 # Usage of previously-generated guard and test details. 2110 2111 elif test[:2] == ("constrained", "specific"): 2112 ref = first(accessor_types) 2113 2114 elif test[:2] == ("constrained", "common"): 2115 ref = first(accessor_general_types) 2116 2117 elif test[:2] == ("guarded", "specific"): 2118 ref = first(accessor_types) 2119 2120 elif test[:2] == ("guarded", "common"): 2121 ref = first(accessor_general_types) 2122 2123 # For attribute-based tests, tentatively identify a dynamic base. 2124 # Such tests allow single or multiple kinds of a type. 2125 2126 elif test[0] == "test" and test[1] in ("common", "specific"): 2127 dynamic_base = test_type 2128 2129 # Static accessors. 2130 2131 if not base and test in self.class_tests: 2132 base = ref and ref.get_origin() or dynamic_base 2133 2134 # Accessors that are not static but whose nature is determined. 2135 2136 elif not base and ref: 2137 dynamic_base = ref.get_origin() 2138 2139 # Determine initial accessor details. 2140 2141 accessor = base or dynamic_base 2142 accessor_kind = len(accessor_kinds) == 1 and first(accessor_kinds) or None 2143 provider_kind = len(provider_kinds) == 1 and first(provider_kinds) or None 2144 2145 # Traverse remaining attributes. 2146 2147 traversed = [] 2148 traversal_modes = [] 2149 2150 while len(attrs) == 1 and not first(attrs).has_kind("<var>"): 2151 attr = first(attrs) 2152 2153 traversed.append(attrname) 2154 traversal_modes.append(accessor_kind == provider_kind and "object" or "class") 2155 2156 # Consume attribute names providing unambiguous attributes. 2157 2158 del remaining[0] 2159 2160 if not remaining: 2161 break 2162 2163 # Update the last static attribute. 2164 2165 if attr.static(): 2166 base = attr.get_origin() 2167 traversed = [] 2168 traversal_modes = [] 2169 2170 # Get the access details. 2171 2172 attrname = remaining[0] 2173 accessor = attr.get_origin() 2174 accessor_kind = attr.get_kind() 2175 provider_kind = self.importer.get_attribute_provider(attr, attrname) 2176 accessor_kinds = [accessor_kind] 2177 provider_kinds = [provider_kind] 2178 2179 # Get the next attribute. 2180 2181 attrs = self.importer.get_attributes(attr, attrname) 2182 2183 # Where many attributes are suggested, no single attribute identity can 2184 # be loaded. 2185 2186 else: 2187 attr = None 2188 2189 # Determine the method of access. 2190 2191 is_assignment = location in self.reference_assignments or const_access in self.reference_assignments 2192 is_invocation = location in self.reference_invocations or const_access in self.reference_invocations 2193 2194 # Identified attribute that must be accessed via its parent. 2195 2196 if attr and attr.get_name() and is_assignment: 2197 final_method = "static-assign"; origin = attr.get_name() 2198 2199 # Static, identified attribute. 2200 2201 elif attr and attr.static(): 2202 final_method = is_assignment and "static-assign" or \ 2203 is_invocation and "static-invoke" or \ 2204 "static" 2205 origin = attr.final() 2206 2207 # All other methods of access involve traversal. 2208 2209 else: 2210 final_method = is_assignment and "assign" or \ 2211 is_invocation and "access-invoke" or \ 2212 "access" 2213 origin = None 2214 2215 # First attribute accessed at a known position via the accessor. 2216 2217 # Static bases support object-relative accesses only. 2218 2219 if base: 2220 first_method = "relative-object" 2221 2222 # Dynamic bases support either object- or class-relative accesses. 2223 2224 elif dynamic_base: 2225 first_method = "relative" + (object_relative and "-object" or "") + \ 2226 (class_relative and "-class" or "") 2227 2228 # The fallback case is always run-time testing and access. 2229 2230 else: 2231 first_method = "check" + (object_relative and "-object" or "") + \ 2232 (class_relative and "-class" or "") 2233 2234 # Determine whether an unbound method is being accessed via an instance, 2235 # requiring a context test. 2236 2237 context_test = "ignore" 2238 2239 # Assignments do not employ the context. 2240 2241 if is_assignment: 2242 pass 2243 2244 # Obtain a selection of possible attributes if no unambiguous attribute 2245 # was identified. 2246 2247 elif not attr: 2248 2249 # Use previously-deduced attributes for a simple ambiguous access. 2250 # Otherwise, use the final attribute name to obtain possible 2251 # attributes. 2252 2253 if len(remaining) > 1: 2254 attrname = remaining[-1] 2255 2256 (class_types, 2257 only_instance_types, 2258 module_types) = self.get_types_for_attribute(attrname) 2259 2260 accessor_kinds = set() 2261 provider_kinds = set() 2262 2263 if class_types: 2264 accessor_kinds.add("<class>") 2265 accessor_kinds.add("<instance>") 2266 provider_kinds.add("<class>") 2267 if only_instance_types: 2268 accessor_kinds.add("<instance>") 2269 provider_kinds.add("<instance>") 2270 if module_types: 2271 accessor_kinds.add("<module>") 2272 provider_kinds.add("<module>") 2273 2274 attrs = set() 2275 for type in combine_types(class_types, only_instance_types, module_types): 2276 attrs.update(self.importer.get_attributes(type, attrname)) 2277 2278 always_unbound = True 2279 have_function = False 2280 have_var = False 2281 2282 # Determine whether all attributes are unbound methods and whether 2283 # functions or unidentified attributes occur. 2284 2285 for attr in attrs: 2286 always_unbound = always_unbound and attr.has_kind("<function>") and attr.name_parent() == attr.parent() 2287 have_function = have_function or attr.has_kind("<function>") 2288 have_var = have_var or attr.has_kind("<var>") 2289 2290 # Test for class-via-instance accesses. 2291 2292 if accessor_kind == "<instance>" and \ 2293 provider_kind == "<class>": 2294 2295 if always_unbound: 2296 context_test = "replace" 2297 else: 2298 context_test = "test" 2299 2300 # Test for the presence of class-via-instance accesses. 2301 2302 elif "<instance>" in accessor_kinds and \ 2303 "<class>" in provider_kinds and \ 2304 (have_function or have_var): 2305 2306 context_test = "test" 2307 2308 # With an unambiguous attribute, determine whether a test is needed. 2309 2310 elif accessor_kind == "<instance>" and \ 2311 provider_kind == "<class>" and \ 2312 (attr.has_kind("<var>") or 2313 attr.has_kind("<function>") and 2314 attr.name_parent() == attr.parent()): 2315 2316 if attr.has_kind("<var>"): 2317 context_test = "test" 2318 else: 2319 context_test = "replace" 2320 2321 # With an unambiguous attribute with ambiguity in the access method, 2322 # generate a test. 2323 2324 elif "<instance>" in accessor_kinds and \ 2325 "<class>" in provider_kinds and \ 2326 (attr.has_kind("<var>") or 2327 attr.has_kind("<function>") and 2328 attr.name_parent() == attr.parent()): 2329 2330 context_test = "test" 2331 2332 # Determine the nature of the context. 2333 2334 context = context_test == "ignore" and "unset" or \ 2335 len(traversed + remaining) == 1 and \ 2336 (base and "base" or "original-accessor") or \ 2337 "final-accessor" 2338 2339 return name, test, test_type, base, \ 2340 traversed, traversal_modes, remaining, \ 2341 context, context_test, \ 2342 first_method, final_method, \ 2343 origin, accessor_kinds 2344 2345 def initialise_access_instructions(self): 2346 2347 "Expand access plans into instruction sequences." 2348 2349 for access_location, access_plan in self.access_plans.items(): 2350 2351 # Obtain the access details. 2352 2353 name, test, test_type, base, \ 2354 traversed, traversal_modes, attrnames, \ 2355 context, context_test, \ 2356 first_method, final_method, \ 2357 origin, accessor_kinds = access_plan 2358 2359 # Emit instructions by appending them to a list. 2360 2361 instructions = [] 2362 emit = instructions.append 2363 2364 # Identify any static original accessor. 2365 2366 if base: 2367 original_accessor = base 2368 2369 # Employ names as contexts unless the context needs testing and 2370 # potentially updating. In such cases, temporary context storage is 2371 # used instead. 2372 2373 elif name and not (context_test == "test" and 2374 final_method in ("access-invoke", "static-invoke")): 2375 original_accessor = "<name>" # refers to the name 2376 2377 # Use a generic placeholder representing the access expression in 2378 # the general case. 2379 2380 else: 2381 original_accessor = "<expr>" 2382 2383 # Prepare for any first attribute access. 2384 2385 if traversed: 2386 attrname = traversed[0] 2387 del traversed[0] 2388 elif attrnames: 2389 attrname = attrnames[0] 2390 del attrnames[0] 2391 2392 # Perform the first access explicitly if at least one operation 2393 # requires it. 2394 2395 access_first_attribute = final_method in ("access", "access-invoke", "assign") or traversed or attrnames 2396 2397 # Determine whether the first access involves assignment. 2398 2399 assigning = not traversed and not attrnames and final_method == "assign" 2400 set_accessor = assigning and "<set_target_accessor>" or "<set_accessor>" 2401 stored_accessor = assigning and "<target_accessor>" or "<accessor>" 2402 2403 # Set the context if already available. 2404 2405 context_var = None 2406 2407 if context == "base": 2408 accessor = context_var = (base,) 2409 elif context == "original-accessor": 2410 2411 # Prevent re-evaluation of any dynamic expression by storing it. 2412 2413 if original_accessor == "<expr>": 2414 if final_method in ("access-invoke", "static-invoke"): 2415 emit(("<set_context>", original_accessor)) 2416 accessor = context_var = ("<context>",) 2417 else: 2418 emit((set_accessor, original_accessor)) 2419 accessor = context_var = (stored_accessor,) 2420 else: 2421 accessor = context_var = (original_accessor,) 2422 2423 # Assigning does not set the context. 2424 2425 elif context in ("final-accessor", "unset") and access_first_attribute: 2426 2427 # Prevent re-evaluation of any dynamic expression by storing it. 2428 2429 if original_accessor == "<expr>": 2430 emit((set_accessor, original_accessor)) 2431 accessor = (stored_accessor,) 2432 else: 2433 accessor = (original_accessor,) 2434 2435 # Apply any test. 2436 2437 if test[0] == "test": 2438 accessor = ("__%s_%s_%s" % test, accessor, test_type) 2439 2440 # Perform the first or final access. 2441 # The access only needs performing if the resulting accessor is used. 2442 2443 remaining = len(traversed + attrnames) 2444 2445 if access_first_attribute: 2446 2447 if first_method == "relative-class": 2448 if assigning: 2449 emit(("__store_via_class", accessor, attrname, "<assexpr>")) 2450 else: 2451 accessor = ("__load_via_class", accessor, attrname) 2452 2453 elif first_method == "relative-object": 2454 if assigning: 2455 emit(("__store_via_object", accessor, attrname, "<assexpr>")) 2456 else: 2457 accessor = ("__load_via_object", accessor, attrname) 2458 2459 elif first_method == "relative-object-class": 2460 if assigning: 2461 emit(("__get_class_and_store", accessor, attrname, "<assexpr>")) 2462 else: 2463 accessor = ("__get_class_and_load", accessor, attrname) 2464 2465 elif first_method == "check-class": 2466 if assigning: 2467 emit(("__check_and_store_via_class", accessor, attrname, "<assexpr>")) 2468 else: 2469 accessor = ("__check_and_load_via_class", accessor, attrname) 2470 2471 elif first_method == "check-object": 2472 if assigning: 2473 emit(("__check_and_store_via_object", accessor, attrname, "<assexpr>")) 2474 else: 2475 accessor = ("__check_and_load_via_object", accessor, attrname) 2476 2477 elif first_method == "check-object-class": 2478 if assigning: 2479 emit(("__check_and_store_via_any", accessor, attrname, "<assexpr>")) 2480 else: 2481 accessor = ("__check_and_load_via_any", accessor, attrname) 2482 2483 # Traverse attributes using the accessor. 2484 2485 if traversed: 2486 for attrname, traversal_mode in zip(traversed, traversal_modes): 2487 assigning = remaining == 1 and final_method == "assign" 2488 2489 # Set the context, if appropriate. 2490 2491 if remaining == 1 and final_method != "assign" and context == "final-accessor": 2492 2493 # Invoked attributes employ a separate context accessed 2494 # during invocation. 2495 2496 if final_method in ("access-invoke", "static-invoke"): 2497 emit(("<set_context>", accessor)) 2498 accessor = context_var = "<context>" 2499 2500 # A private context within the access is otherwise 2501 # retained. 2502 2503 else: 2504 emit(("<set_private_context>", accessor)) 2505 accessor = context_var = "<private_context>" 2506 2507 # Perform the access only if not achieved directly. 2508 2509 if remaining > 1 or final_method in ("access", "access-invoke", "assign"): 2510 2511 if traversal_mode == "class": 2512 if assigning: 2513 emit(("__store_via_class", accessor, attrname, "<assexpr>")) 2514 else: 2515 accessor = ("__load_via_class", accessor, attrname) 2516 else: 2517 if assigning: 2518 emit(("__store_via_object", accessor, attrname, "<assexpr>")) 2519 else: 2520 accessor = ("__load_via_object", accessor, attrname) 2521 2522 remaining -= 1 2523 2524 if attrnames: 2525 for attrname in attrnames: 2526 assigning = remaining == 1 and final_method == "assign" 2527 2528 # Set the context, if appropriate. 2529 2530 if remaining == 1 and final_method != "assign" and context == "final-accessor": 2531 2532 # Invoked attributes employ a separate context accessed 2533 # during invocation. 2534 2535 if final_method in ("access-invoke", "static-invoke"): 2536 emit(("<set_context>", accessor)) 2537 accessor = context_var = "<context>" 2538 2539 # A private context within the access is otherwise 2540 # retained. 2541 2542 else: 2543 emit(("<set_private_context>", accessor)) 2544 accessor = context_var = "<private_context>" 2545 2546 # Perform the access only if not achieved directly. 2547 2548 if remaining > 1 or final_method in ("access", "access-invoke", "assign"): 2549 2550 # Constrain instructions involving certain special 2551 # attribute names. 2552 2553 to_search = attrname == "__data__" and "object" or "any" 2554 2555 if assigning: 2556 emit(("__check_and_store_via_%s" % to_search, accessor, attrname, "<assexpr>")) 2557 else: 2558 accessor = ("__check_and_load_via_%s" % to_search, accessor, attrname) 2559 2560 remaining -= 1 2561 2562 # Define or emit the means of accessing the actual target. 2563 2564 # Assignments to known attributes. 2565 2566 if final_method == "static-assign": 2567 parent, attrname = origin.rsplit(".", 1) 2568 emit(("__store_via_object", parent, attrname, "<assexpr>")) 2569 2570 # Invoked attributes employ a separate context. 2571 2572 elif final_method in ("static", "static-invoke"): 2573 accessor = ("__load_static_ignore", origin) 2574 2575 # Wrap accesses in context operations. 2576 2577 if context_test == "test": 2578 2579 # Test and combine the context with static attribute details. 2580 2581 if final_method == "static": 2582 emit(("__load_static_test", context_var, origin)) 2583 2584 # Test the context, storing it separately if required for the 2585 # immediately invoked static attribute. 2586 2587 elif final_method == "static-invoke": 2588 emit(("<test_context_static>", context_var, origin)) 2589 2590 # Test the context, storing it separately if required for an 2591 # immediately invoked attribute. 2592 2593 elif final_method == "access-invoke": 2594 emit(("<test_context_revert>", context_var, accessor)) 2595 2596 # Test the context and update the attribute details if 2597 # appropriate. 2598 2599 else: 2600 emit(("__test_context", context_var, accessor)) 2601 2602 elif context_test == "replace": 2603 2604 # Produce an object with updated context. 2605 2606 if final_method == "static": 2607 emit(("__load_static_replace", context_var, origin)) 2608 2609 # Omit the context update operation where the target is static 2610 # and the context is recorded separately. 2611 2612 elif final_method == "static-invoke": 2613 pass 2614 2615 # If a separate context is used for an immediate invocation, 2616 # produce the attribute details unchanged. 2617 2618 elif final_method == "access-invoke": 2619 emit(accessor) 2620 2621 # Update the context in the attribute details. 2622 2623 else: 2624 emit(("__update_context", context_var, accessor)) 2625 2626 # Omit the accessor for assignments and for invocations of static 2627 # targets. 2628 2629 elif final_method not in ("assign", "static-assign", "static-invoke"): 2630 emit(accessor) 2631 2632 # Produce an advisory instruction regarding the context. 2633 2634 if context_var: 2635 emit(("<context_identity>", context_var)) 2636 2637 self.access_instructions[access_location] = instructions 2638 self.accessor_kinds[access_location] = accessor_kinds 2639 2640 # vim: tabstop=4 expandtab shiftwidth=4