1 #!/usr/bin/env python 2 3 """ 4 Annotate program node structures. The code in this module operates upon nodes 5 which are produced when simplifying AST node trees originating from the compiler 6 module. 7 8 Copyright (C) 2006 Paul Boddie <paul@boddie.org.uk> 9 10 This software is free software; you can redistribute it and/or 11 modify it under the terms of the GNU General Public License as 12 published by the Free Software Foundation; either version 2 of 13 the License, or (at your option) any later version. 14 15 This software is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License for more details. 19 20 You should have received a copy of the GNU General Public 21 License along with this library; see the file LICENCE.txt 22 If not, write to the Free Software Foundation, Inc., 23 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA 24 25 -------- 26 27 To use this module, the easiest approach is to use the load function: 28 29 load(filename, builtins) 30 31 To control module importing, an importer should be constructed and employed. 32 Here, the standard path for module searching is used: 33 34 importer = Importer(sys.path) 35 load(filename, builtins, importer) 36 37 Underneath the load function, the annotate function provides support for 38 annotating modules already processed by simplify and fixnames: 39 40 annotate(module, builtins) 41 42 And at the most basic level, the most intricate approach involves obtaining an 43 Annotator object: 44 45 annotator = Annotator() 46 47 Then, processing an existing module with it: 48 49 annotator.process(module) 50 51 If a module containing built-in classes and functions has already been 52 annotated, such a module should be passed in as an additional argument: 53 54 annotator.process(module, builtins) 55 """ 56 57 from simplified import * 58 import simplify, fixnames # for the load function 59 import compiler 60 import os 61 62 class System: 63 64 """ 65 A class maintaining the state of the annotation system. When the system 66 counter can no longer be incremented by any annotation operation, the 67 system may be considered stable and fully annotated. 68 """ 69 70 def __init__(self): 71 self.count = 0 72 73 def init(self, node): 74 75 "Initialise a 'node' for annotation." 76 77 if not hasattr(node, "types"): 78 node.types = [] 79 80 def annotate(self, node, types): 81 82 "Annotate the given 'node' with the given 'types'." 83 84 self.init(node) 85 self.combine(node.types, types) 86 87 def combine(self, target, types): 88 89 """ 90 Combine the 'target' list with the given 'types', counting new members. 91 """ 92 93 for type in types: 94 if type not in target: 95 target.append(type) 96 self.count += 1 97 98 system = System() 99 100 # Exceptions. 101 102 class AnnotationError(SimplifiedError): 103 104 "An error in the annotation process." 105 106 pass 107 108 class AnnotationMessage(Exception): 109 110 "A lesser annotation error." 111 112 pass 113 114 # Annotation. 115 116 class Annotator(Visitor): 117 118 """ 119 The type annotator which traverses the program nodes, typically depth-first, 120 and maintains a record of the current set of types applying to the currently 121 considered operation. Such types are also recorded on the nodes, and a 122 special "system" record is maintained to monitor the level of annotation 123 activity with a view to recognising when no more annotations are possible. 124 125 Throughout the annotation activity, type information consists of lists of 126 Attribute objects where such objects retain information about the context of 127 the type (since a value in the program may be associated with an object or 128 class) and the actual type of the value being manipulated. Upon accessing 129 attribute information on namespaces, additional accessor information is also 130 exchanged - this provides a means of distinguishing between the different 131 types possible when the means of constructing the namespace may depend on 132 run-time behaviour. 133 134 Covered: Assign, CheckExc, Conditional, Global, Import, InvokeBlock, 135 InvokeFunction, LoadAttr, LoadExc, LoadName, LoadRef, LoadTemp, 136 Module, Not, Pass, Raise, ReleaseTemp, ReturnFromBlock, 137 ReturnFromFunction, StoreAttr, StoreName, StoreTemp, Subprogram, 138 Try. 139 """ 140 141 def __init__(self, importer=None): 142 143 "Initialise the visitor with an optional 'importer'." 144 145 Visitor.__init__(self) 146 self.system = system 147 self.importer = importer or Importer() 148 149 # Satisfy visitor issues. 150 151 self.visitor = self 152 153 def process(self, module, builtins=None): 154 155 """ 156 Process the given 'module', using the optional 'builtins' to access 157 built-in classes and functions. 158 """ 159 160 self.subprograms = [] 161 self.current_subprograms = [] 162 self.current_namespaces = [] 163 self.namespace = None 164 self.module = module 165 166 # Give constants their own namespace. 167 168 for value, constant in module.simplifier.constants.items(): 169 constant.namespace = Namespace() 170 171 # Process the module, supplying builtins if possible. 172 173 self.builtins = builtins 174 self.global_namespace = Namespace() 175 176 if builtins is not None: 177 self.builtins_namespace = builtins.namespace 178 else: 179 self.builtins_namespace = self.global_namespace 180 181 return self.process_node(module, self.global_namespace) 182 183 def process_node(self, node, locals): 184 185 """ 186 Process a subprogram or module 'node', indicating the initial 'locals'. 187 Return an annotated subprogram or module. Note that this method may 188 mutate nodes in the original program. 189 """ 190 191 # Record the current subprogram and namespace. 192 193 self.current_subprograms.append(node) 194 195 # Determine the namespace. 196 197 self.current_namespaces.append(self.namespace) 198 self.namespace = locals 199 200 # Add namespace details to any structure involved. 201 202 if getattr(node, "structure", None) is not None: 203 node.structure.namespace = Namespace() 204 205 # Initialise bases where appropriate. 206 207 if hasattr(node.structure, "bases"): 208 base_refs = [] 209 for base in node.structure.bases: 210 self.dispatch(base) 211 base_refs.append(self.namespace.types) 212 node.structure.base_refs = base_refs 213 214 # Dispatch to the code itself. 215 216 node.namespace = self.namespace 217 result = self.dispatch(node) 218 result.namespace = self.namespace 219 220 # Obtain the return values. 221 222 self.last_returns = self.namespace.returns 223 self.last_raises = self.namespace.raises 224 self.returned_locals = self.namespace.return_locals 225 226 # Restore the previous subprogram and namespace. 227 228 self.namespace = self.current_namespaces.pop() 229 self.current_subprograms.pop() 230 231 return result 232 233 def annotate(self, node, types=None): 234 235 """ 236 Annotate the given 'node' in the system, using either the optional 237 'types' or the namespace's current type information. 238 """ 239 240 self.system.annotate(node, types or self.namespace.types) 241 242 def annotate_parameters(self, node, items): 243 244 """ 245 Annotate the given 'node' using the given 'items' and updating the 246 system's annotation counter. 247 """ 248 249 if not hasattr(node, "paramtypes"): 250 node.paramtypes = {} 251 252 for param, types in items: 253 if not node.paramtypes.has_key(param): 254 node.paramtypes[param] = [] 255 self.system.combine(node.paramtypes[param], types) 256 257 # Visitor methods. 258 259 def default(self, node): 260 261 """ 262 Process the given 'node', given that it does not have a specific 263 handler. 264 """ 265 266 raise AnnotationMessage, "Node '%s' not supported." % node 267 268 def dispatch(self, node, *args): 269 try: 270 return Visitor.dispatch(self, node, *args) 271 except AnnotationError, exc: 272 exc.add(node) 273 raise 274 except AnnotationMessage, exc: 275 raise AnnotationError(exc, node) 276 277 # Specific node methods. 278 279 def visitAssign(self, assign): 280 281 """ 282 Return the 'assign' node whose contents (merely a group of nodes) have 283 been processed. 284 """ 285 286 assign.code = self.dispatches(assign.code) 287 return assign 288 289 def visitCheckExc(self, checkexc): 290 291 """ 292 Return the 'checkexc' node, processing the expression to find the 293 possible types of the exception, and processing each choice to build a 294 list of checked types for the exception. 295 """ 296 297 checkexc.expr = self.dispatch(checkexc.expr) 298 expr_types = self.namespace.types 299 choice_types = [] 300 choices = [] 301 for choice in checkexc.choices: 302 choices.append(self.dispatch(choice)) 303 choice_types += self.namespace.types 304 for expr_type in expr_types: 305 if expr_type.type.get_class() not in choice_types: 306 self._prune_non_accesses(checkexc.expr, expr_type) 307 return checkexc 308 309 def visitConditional(self, conditional): 310 311 """ 312 Return the 'conditional' node, processing the test, body and else 313 clauses and recording their processed forms. The body and else clauses 314 are processed within their own namespaces, and the test is also 315 processed in its own namespace if 'isolate_test' is set on the 316 'conditional' node. 317 """ 318 319 # Conditionals keep local namespace changes isolated. 320 # With Return nodes inside the body/else sections, the changes are 321 # communicated to the caller. 322 323 is_module = self.namespace is self.module.namespace 324 325 # Where the test is closely associated with the body, save the namespace 326 # before entering the test. 327 328 if conditional.isolate_test: 329 saved_namespace = self.namespace 330 self.namespace = Namespace() 331 if is_module: 332 self.module.namespace = self.namespace 333 self.namespace.merge_namespace(saved_namespace) 334 335 conditional.test = self.dispatch(conditional.test) 336 337 # Where the test may affect the body and the else clause, save the 338 # namespace after processing the test. 339 340 if not conditional.isolate_test: 341 saved_namespace = self.namespace 342 self.namespace = Namespace() 343 if is_module: 344 self.module.namespace = self.namespace 345 self.namespace.merge_namespace(saved_namespace) 346 347 # Process the body clause. 348 349 conditional.body = self.dispatches(conditional.body) 350 body_namespace = self.namespace 351 352 # Use the saved namespace as a template for the else clause. 353 354 self.namespace = Namespace() 355 if is_module: 356 self.module.namespace = self.namespace 357 self.namespace.merge_namespace(saved_namespace) 358 359 # Process the else clause. 360 361 conditional.else_ = self.dispatches(conditional.else_) 362 else_namespace = self.namespace 363 364 # Merge the body and else namespaces. 365 366 self.namespace = Namespace() 367 if is_module: 368 self.module.namespace = self.namespace 369 self.namespace.merge_namespace(body_namespace) 370 self.namespace.merge_namespace(else_namespace) 371 372 # NOTE: Test of exception type pruning based on the test/body. 373 374 if conditional.isolate_test: 375 for exc_type in body_namespace.raises: 376 self.namespace.revoke_exception_type(exc_type) 377 378 return conditional 379 380 def visitGlobal(self, global_): 381 382 """ 383 Return the 'global_' node unprocessed since namespaces should have 384 already been altered to take global names into consideration. 385 """ 386 387 return global_ 388 389 def visitImport(self, import_): 390 391 """ 392 Return the 'import_' node, importing the module with the stated name 393 and storing details on the node. 394 """ 395 396 module = self.importer.load(import_.name, self.builtins, getattr(import_, "alias", None)) 397 if module is not None: 398 self.namespace.set_types([module]) 399 else: 400 self.namespace.set_types([]) 401 self.annotate(import_) # mainly for viewing purposes 402 return import_ 403 404 def _visitInvoke(self, invoke, invocation_types, have_args): 405 406 """ 407 Return the processed 'invoke' node, using the given 'invocation_types' 408 as the list of callables to be investigated for instantiation or for the 409 invocation of functions or blocks. If 'have_args' is a true value, any 410 invocation or instantiation will involve arguments. 411 """ 412 413 # Now locate and invoke the subprogram. This can be complicated because 414 # the target may be a class or object, and there may be many different 415 # related subprograms. 416 417 invocations = [] 418 419 # Visit each callable in turn, finding subprograms. 420 421 for attr in invocation_types: 422 423 # Deal with class invocations by providing instance objects. 424 # Here, each class is queried for the __init__ method, which may 425 # exist for some combinations of classes in a hierarchy but not for 426 # others. 427 428 if isinstance(attr.type, Class): 429 attributes = get_attributes(attr.type, "__init__") 430 431 # Deal with object invocations by using __call__ methods. 432 433 elif isinstance(attr.type, Instance): 434 attributes = get_attributes(attr.type, "__call__") 435 436 # Normal functions or methods are more straightforward. 437 # Here, we model them using an attribute with no context and with 438 # no associated accessor. 439 440 else: 441 attributes = [(attr, None)] 442 443 # Inspect each attribute and extract the subprogram. 444 445 for attribute, accessor in attributes: 446 447 # If a class is involved, presume that it must create a new 448 # object. 449 450 if isinstance(attr.type, Class): 451 452 # Instantiate the class. 453 # NOTE: Should probably only allocate a single instance. 454 455 instance = self.new_instance(invoke, "new", attr.type.full_name(), attr.type) 456 457 # For instantiations, switch the context. 458 459 if attribute is not None: 460 attribute = Attribute(instance, attribute.type) 461 462 # Skip cases where no callable is found. 463 464 if attribute is not None: 465 466 # If a subprogram is defined, invoke it. 467 468 self.invoke_subprogram(invoke, attribute) 469 if attribute.type not in invocations: 470 invocations.append(attribute.type) 471 472 elif not isinstance(attr.type, Class): 473 print "Invocation type is None for", accessor 474 475 else: 476 477 # Test to see if no arguments were supplied in cases where no 478 # initialiser was found. 479 480 if have_args: 481 raise AnnotationMessage, "No initialiser found for '%s' with arguments." % attr.type 482 483 # Special case: initialisation. 484 485 if isinstance(attr.type, Class): 486 487 # Associate the instance with the result of this invocation. 488 489 self.namespace.set_types([Attribute(None, instance)]) 490 self.annotate(invoke) 491 492 # Remember the invocations that were found, along with the return type 493 # information. 494 495 invoke.invocations = invocations 496 self.namespace.set_types(getattr(invoke, "types", [])) 497 return invoke 498 499 def visitInvokeBlock(self, invoke): 500 501 """ 502 Return the processed 'invoke' node, first finding the callables 503 indicated by the expression. 504 """ 505 506 invoke.expr = self.dispatch(invoke.expr) 507 invocation_types = self.namespace.types 508 return self._visitInvoke(invoke, invocation_types, have_args=0) 509 510 def visitInvokeFunction(self, invoke): 511 512 """ 513 Return the processed 'invoke' node, first finding the callables 514 indicated by the expression. 515 """ 516 517 invoke.expr = self.dispatch(invoke.expr) 518 invocation_types = self.namespace.types 519 520 # Invocation processing starts with making sure that the arguments have 521 # been processed. 522 523 return self._visitInvoke(invoke, invocation_types, have_args=self.process_args(invoke)) 524 525 def visitLoadAttr(self, loadattr): 526 527 """ 528 Return the 'loadattr' node, processing and storing the expression, and 529 using the expression's types to construct records of accesses and 530 non-accesses using the stated attribute name. 531 """ 532 533 loadattr.expr = self.dispatch(loadattr.expr) 534 types = [] 535 non_accesses = [] 536 accesses = {} 537 for attr in self.namespace.types: 538 attributes = get_attributes(attr.type, loadattr.name) 539 if not attributes: 540 if not attr in non_accesses: 541 non_accesses.append(attr) 542 combine(self.namespace.raises, self.get_builtin_instances("AttributeError")) 543 544 # Revoke this type from any name involved. 545 546 self._prune_non_accesses(loadattr.expr, attr) 547 548 for attribute, accessor in attributes: 549 if attribute is not None: 550 types.append(attribute) 551 if not accesses.has_key(attr.type): 552 accesses[attr.type] = [] 553 if not (attribute, accessor) in accesses[attr.type]: 554 accesses[attr.type].append((attribute, accessor)) 555 else: 556 if not attr in non_accesses: 557 non_accesses.append(attr) 558 combine(self.namespace.raises, self.get_builtin_instances("AttributeError")) 559 560 # Revoke this type from any name involved. 561 562 self._prune_non_accesses(loadattr.expr, attr) 563 564 if not types: 565 print "No attribute found for", loadattr.name, "given", self.namespace.types 566 self.namespace.set_types(types) 567 loadattr.non_accesses = non_accesses 568 loadattr.accesses = accesses 569 self.annotate(loadattr) 570 return loadattr 571 572 def _prune_non_accesses(self, expr, attr): 573 574 """ 575 Prune type information from 'expr' where the given 'attr' has been 576 shown to be a non-access. 577 """ 578 579 if isinstance(expr, LoadName): 580 self.namespace.revoke(expr.name, attr) 581 elif isinstance(expr, LoadExc): 582 self.namespace.revoke_exception_type(attr) 583 elif isinstance(expr, LoadTemp): 584 self.namespace.revoke_temp_type(getattr(expr, "index", None), attr) 585 586 # LoadAttr cannot be pruned since this might unintentionally prune 587 # legitimate types from other applications of the referenced type, it 588 # almost certainly doesn't take "concurrent" mutation into 589 # consideration (where in a running program, the pruned type is actually 590 # reintroduced, making the pruning invalid), and there is no easy way of 591 # preserving the meaning of a namespace without either creating lots of 592 # specialised instances, and even then... 593 594 #elif isinstance(expr, LoadAttr): 595 # for expr_attr in expr.expr.types: 596 # if hasattr(expr_attr.type, "namespace"): 597 # expr_attr.type.namespace.revoke(expr.name, attr) 598 599 def visitLoadExc(self, loadexc): 600 601 """ 602 Return the 'loadexc' node, discovering the possible exception types 603 raised. 604 """ 605 606 self.namespace.set_types(self.namespace.raises[:]) 607 self.annotate(loadexc) 608 return loadexc 609 610 def visitLoadName(self, loadname): 611 612 """ 613 Return the 'loadname' node, processing the name information on the node 614 to determine which types are involved with the name. 615 """ 616 617 self.namespace.set_types(self.namespace.load(loadname.name)) 618 result = loadname 619 self.annotate(result) 620 return result 621 622 def visitLoadRef(self, loadref): 623 624 """ 625 Return the 'loadref' node, obtaining type information about the 626 reference stated on the node. 627 """ 628 629 self.namespace.set_types([Attribute(None, loadref.ref)]) 630 self.annotate(loadref) 631 return loadref 632 633 def visitLoadTemp(self, loadtemp): 634 635 """ 636 Return the 'loadtemp' node, obtaining type information about the 637 temporary variable accessed, and removing variable information where the 638 'release' attribute has been set on the node. 639 """ 640 641 index = getattr(loadtemp, "index", None) 642 try: 643 if getattr(loadtemp, "release", 0): 644 self.namespace.set_types(self.namespace.temp[index].pop()) 645 else: 646 self.namespace.set_types(self.namespace.temp[index][-1]) 647 except KeyError: 648 raise AnnotationMessage, "Temporary store index '%s' not defined." % index 649 self.annotate(loadtemp) 650 return loadtemp 651 652 def visitModule(self, module): 653 654 """ 655 Return the processed 'module' whose contents (merely a group of nodes) 656 are processed. 657 """ 658 659 module.code = self.dispatches(module.code) 660 return module 661 662 def visitNot(self, not_): 663 664 "Return the 'not_' node whose expression is processed." 665 666 not_.expr = self.dispatch(not_.expr) 667 return not_ 668 669 def visitPass(self, pass_): 670 671 "Return the unprocessed 'pass_' node." 672 673 return pass_ 674 675 def visitRaise(self, raise_): 676 677 """ 678 Return the 'raise_' node, processing any traceback information along 679 with the raised exception expression, converting the node into a kind of 680 invocation where the expression is found not to be an invocation itself. 681 This node affects the namespace, adding exception types to the list of 682 those raised in the namespace. 683 """ 684 685 if getattr(raise_, "traceback", None) is not None: 686 raise_.traceback = self.dispatch(raise_.traceback) 687 raise_.expr = self.dispatch(raise_.expr) 688 689 # Handle bare name exceptions by converting any classes to instances. 690 691 if not isinstance(raise_.expr, InvokeFunction): 692 raise_.pos_args = [] 693 raise_.kw_args = {} 694 raise_.star = None 695 raise_.dstar = None 696 types = [] 697 for attr in self.namespace.types: 698 if isinstance(attr.type, Class): 699 self._visitInvoke(raise_, [attr], have_args=0) 700 types += self.namespace.types 701 else: 702 types = self.namespace.types 703 704 combine(self.namespace.raises, types) 705 return raise_ 706 707 def visitReleaseTemp(self, releasetemp): 708 709 """ 710 Return the 'releasetemp' node, removing temporary variable information 711 from the current namespace. 712 """ 713 714 index = getattr(releasetemp, "index", None) 715 try: 716 self.namespace.temp[index].pop() 717 except KeyError: 718 raise AnnotationMessage, "Temporary store index '%s' not defined." % index 719 except IndexError: 720 pass #raise AnnotationMessage, "Temporary store index '%s' is empty." % index 721 return releasetemp 722 723 def visitReturn(self, return_): 724 725 """ 726 Return the 'return_' node, processing any expression and obtaining type 727 information to be accumulated in the current namespace's list of return 728 types. A snapshot of the namespace is taken for the purposes of 729 reconciling or merging namespaces where subprograms actually share 730 locals with their callers. 731 """ 732 733 if hasattr(return_, "expr"): 734 return_.expr = self.dispatch(return_.expr) 735 combine(self.namespace.returns, self.namespace.types) 736 self.annotate(return_) 737 self.namespace.snapshot() 738 return return_ 739 740 visitReturnFromBlock = visitReturn 741 visitReturnFromFunction = visitReturn 742 743 def visitStoreAttr(self, storeattr): 744 745 """ 746 Return the 'storeattr' node, processing the expression and target, and 747 using the type information obtained to build records of legitimate 748 writes to the stated attribute, along with "impossible" non-writes to 749 the attribute. 750 """ 751 752 storeattr.expr = self.dispatch(storeattr.expr) 753 expr = self.namespace.types 754 storeattr.lvalue = self.dispatch(storeattr.lvalue) 755 writes = {} 756 non_writes = [] 757 for attr in self.namespace.types: 758 # NOTE: Impose "atomic" constraints on certain types. 759 if attr is None: 760 if not attr in non_writes: 761 non_writes.append(attr) 762 continue 763 attr.type.namespace.add(storeattr.name, expr) 764 writes[attr.type] = attr.type.namespace.load(storeattr.name) 765 if not writes: 766 print "Unable to store attribute", storeattr.name, "given", self.namespace.types 767 storeattr.writes = writes 768 storeattr.non_writes = non_writes 769 return storeattr 770 771 def visitStoreName(self, storename): 772 773 """ 774 Return the 'storename' node, processing the expression on the node and 775 associating the type information obtained with the stated name in the 776 current namespace. 777 """ 778 779 storename.expr = self.dispatch(storename.expr) 780 self.namespace.store(storename.name, self.namespace.types) 781 return storename 782 783 def visitStoreTemp(self, storetemp): 784 785 """ 786 Return the 'storetemp' node, processing the expression on the node and 787 associating the type information obtained with a temporary variable in 788 the current namespace. 789 """ 790 791 storetemp.expr = self.dispatch(storetemp.expr) 792 index = getattr(storetemp, "index", None) 793 if not self.namespace.temp.has_key(index): 794 self.namespace.temp[index] = [] 795 self.namespace.temp[index].append(self.namespace.types) 796 return storetemp 797 798 def visitSubprogram(self, subprogram): 799 800 """ 801 Return the 'subprogram' node, processing its contents (a group of nodes 802 comprising the subprogram). 803 """ 804 805 subprogram.code = self.dispatches(subprogram.code) 806 return subprogram 807 808 def visitTry(self, try_): 809 810 """ 811 Return the 'try_' node, processing the body clause in its own namespace 812 derived from the current namespace, processing any handler clause using 813 the namespace information accumulated in the body, and processing any 814 else and finally clauses, attempting to supply each with appropriate 815 namespace information. 816 """ 817 818 is_module = self.namespace is self.module.namespace 819 820 try_.body = self.dispatches(try_.body) 821 822 # Save the namespace from the body. 823 824 body_namespace = Namespace() 825 body_namespace.merge_namespace(self.namespace) 826 827 # Process the handler. 828 829 if hasattr(try_, "handler"): 830 try_.handler = self.dispatches(try_.handler) 831 832 # Save the namespace from the handler. 833 834 handler_namespace = Namespace() 835 handler_namespace.merge_namespace(self.namespace) 836 837 # Remember the raised exceptions encountered so far. 838 839 raises = self.namespace.raises 840 841 # Process the else clause. 842 843 if hasattr(try_, "else_"): 844 845 # Restore the body namespace for the else clause. 846 847 self.namespace = body_namespace 848 if is_module: 849 self.module.namespace = self.namespace 850 851 # Empty the raised exceptions for the else clause. 852 853 self.namespace.raises = [] 854 try_.else_ = self.dispatches(try_.else_) 855 self.namespace.raises = raises 856 857 # Merge the namespaces. 858 859 self.namespace = Namespace() 860 if is_module: 861 self.module.namespace = self.namespace 862 self.namespace.merge_namespace(body_namespace) 863 self.namespace.merge_namespace(handler_namespace) 864 865 # Process the finally clause, if any. 866 867 try_.finally_ = self.dispatches(try_.finally_) 868 return try_ 869 870 # Utility methods. 871 872 def get_builtin_instances(self, name): 873 return [Attribute(None, self._new_instance(attr.type)) for attr in self.builtins.namespace[name]] 874 875 def new_instance(self, node, reason, target, type): 876 877 "Create, on the given 'node', a new instance with the given 'type'." 878 879 if not hasattr(node, "instances"): 880 node.instances = {} 881 882 if not node.instances.has_key((reason, target, type)): 883 instance = self._new_instance(type) 884 node.instances[(reason, target, type)] = instance 885 886 return node.instances[(reason, target, type)] 887 888 def _new_instance(self, type): 889 890 # Insist on a single instance per type. 891 # NOTE: Strategy-dependent instantiation. 892 893 if len(type.instances) == 0: 894 instance = Instance() 895 instance.namespace = Namespace() 896 instance.namespace.store("__class__", [Attribute(None, type)]) 897 type.instances.append(instance) 898 else: 899 instance = type.instances[0] 900 901 return instance 902 903 def invoke_subprogram(self, invoke, attribute): 904 905 """ 906 Invoke using the given 'invoke' node the subprogram represented by the 907 given 'attribute'. 908 """ 909 910 # Test for context information, making it into a real attribute. 911 912 if attribute.context is not None: 913 context = Attribute(None, attribute.context) 914 target = attribute.type 915 else: 916 context = None 917 target = attribute.type 918 919 # Test to see if anything has changed. 920 921 if hasattr(invoke, "syscount") and invoke.syscount == self.system.count: 922 return 923 924 # Remember the state of the system. 925 926 else: 927 invoke.syscount = self.system.count 928 929 # Provide the correct namespace for the invocation. 930 # This may be a "shared" namespace... 931 932 if getattr(invoke, "share_locals", 0): 933 namespace = Namespace() 934 namespace.merge_namespace(self.namespace, everything=0) 935 using_module_namespace = self.namespace is self.module.namespace 936 937 # Or it may be a structure... 938 939 elif getattr(target, "structure", None): 940 namespace = Namespace() 941 using_module_namespace = 0 942 943 # Or it may be a new namespace populated with the supplied parameters. 944 945 else: 946 items = self.make_items(invoke, target, context) 947 namespace = Namespace() 948 namespace.merge_items(items) 949 using_module_namespace = 0 950 951 # NOTE: Avoid PEP 227 (nested scopes) whilst permitting references to a 952 # NOTE: subprogram within itself. Do not define the name of the function 953 # NOTE: within a method definition. 954 955 if getattr(target, "name", None) is not None and not getattr(target, "is_method", 0): 956 namespace.store(target.name, [Attribute(None, target)]) 957 958 # Process the subprogram. 959 # In order to keep global accesses working, the module namespace must be 960 # adjusted. 961 962 if using_module_namespace: 963 self.module.namespace = namespace 964 965 self.process_node(target, namespace) 966 967 # NOTE: Improve and verify this. 968 # If the invocation returns a value, acquire the return types. 969 970 if getattr(target, "returns_value", 0): 971 self.namespace.set_types(self.last_returns) 972 self.annotate(invoke) 973 974 # If it is a normal block, merge the locals. 975 # This can happen in addition to the above because for things like 976 # logical expressions, the namespace can be modified whilst values are 977 # returned as results. 978 979 if getattr(invoke, "share_locals", 0): 980 self.namespace.reset() 981 982 # Merge the locals snapshots. 983 984 for locals in self.returned_locals: 985 986 # For blocks returning values (such as operations), do not merge 987 # snapshots or results. 988 989 if getattr(target, "returns_value", 0): 990 self.namespace.merge_namespace(locals, everything=0) 991 992 # For blocks not returning values (such as loops), merge 993 # snapshots and results since they contain details of genuine 994 # returns. 995 996 else: 997 self.namespace.merge_namespace(locals) 998 999 # Incorporate any raised exceptions. 1000 1001 combine(self.namespace.raises, self.last_raises) 1002 1003 # In order to keep global accesses working, the module namespace must be 1004 # adjusted. 1005 1006 if using_module_namespace: 1007 self.module.namespace = self.namespace 1008 1009 def process_args(self, invocation): 1010 1011 """ 1012 Process the arguments associated with an 'invocation'. Return whether 1013 any arguments were processed. 1014 """ 1015 1016 invocation.pos_args = self.dispatches(invocation.pos_args) 1017 invocation.kw_args = self.dispatch_dict(invocation.kw_args) 1018 1019 # Get type information for star and dstar arguments. 1020 1021 if invocation.star is not None: 1022 param, default = invocation.star 1023 default = self.dispatch(default) 1024 invocation.star = param, default 1025 1026 if invocation.dstar is not None: 1027 param, default = invocation.dstar 1028 default = self.dispatch(default) 1029 invocation.dstar = param, default 1030 1031 if invocation.pos_args or invocation.kw_args or invocation.star or invocation.dstar: 1032 return 1 1033 else: 1034 return 0 1035 1036 def make_items(self, invocation, subprogram, context): 1037 1038 """ 1039 Make an items mapping for the 'invocation' of the 'subprogram' using the 1040 given 'context' (which may be None). 1041 """ 1042 1043 if context is not None: 1044 pos_args = [Self(context)] + invocation.pos_args 1045 else: 1046 pos_args = invocation.pos_args 1047 1048 # Duplicate the keyword arguments - we remove them in processing below. 1049 1050 kw_args = {} 1051 kw_args.update(invocation.kw_args) 1052 1053 # Sort the arguments into positional and keyword arguments. 1054 1055 params = subprogram.params 1056 items = [] 1057 star_args = [] 1058 1059 # Match each positional argument, taking excess arguments as star args. 1060 1061 for arg in pos_args: 1062 if params: 1063 param, default = params[0] 1064 if arg is None: 1065 arg = default 1066 if hasattr(arg, "types"): 1067 items.append((param, arg.types)) 1068 else: 1069 items.append((param, [])) # Annotation has not succeeded. 1070 params = params[1:] 1071 else: 1072 star_args.append(arg) 1073 1074 # Collect the remaining defaults. 1075 1076 while params: 1077 param, default = params[0] 1078 if kw_args.has_key(param): 1079 arg = kw_args[param] 1080 del kw_args[param] 1081 elif default is not None: 1082 arg = self.dispatch(default) 1083 else: 1084 raise AnnotationMessage, "No argument supplied in '%s' for parameter '%s'." % (subprogram, param) 1085 if hasattr(arg, "types"): 1086 items.append((param, arg.types)) 1087 else: 1088 items.append((param, [])) # Annotation has not succeeded. 1089 params = params[1:] 1090 1091 dstar_args = kw_args.items() 1092 1093 # Construct temporary objects. 1094 1095 if star_args: 1096 star_invocation = self.make_star_args(invocation, subprogram, star_args) 1097 self.dispatch(star_invocation) 1098 star_types = star_invocation.types 1099 else: 1100 star_types = None 1101 1102 if dstar_args: 1103 dstar_invocation = self.make_dstar_args(invocation, subprogram, dstar_args) 1104 self.dispatch(dstar_invocation) 1105 dstar_types = dstar_invocation.types 1106 else: 1107 dstar_types = None 1108 1109 # NOTE: Merge the objects properly. 1110 1111 star_types = star_types or invocation.star and invocation.star.types 1112 dstar_types = dstar_types or invocation.dstar and invocation.dstar.types 1113 1114 # Add star and dstar. 1115 1116 if star_types is not None: 1117 if subprogram.star is not None: 1118 param, default = subprogram.star 1119 items.append((param, star_types)) 1120 else: 1121 raise AnnotationMessage, "Invocation provides unwanted *args." 1122 elif subprogram.star is not None: 1123 param, default = subprogram.star 1124 if not hasattr(default, "types"): 1125 subprogram.star = param, self.dispatch(default) # NOTE: Review reprocessing. 1126 items.append((param, default.types)) 1127 1128 if dstar_types is not None: 1129 if subprogram.dstar is not None: 1130 param, default = subprogram.dstar 1131 items.append((param, dstar_types)) 1132 else: 1133 raise AnnotationMessage, "Invocation provides unwanted **args." 1134 elif subprogram.dstar is not None: 1135 param, default = subprogram.dstar 1136 if not hasattr(default, "types"): 1137 subprogram.dstar = param, self.dispatch(default) # NOTE: Review reprocessing. 1138 items.append((param, default.types)) 1139 1140 # Record the parameter types. 1141 1142 self.annotate_parameters(subprogram, items) 1143 return subprogram.paramtypes.items() 1144 1145 def make_star_args(self, invocation, subprogram, star_args): 1146 1147 "Make a subprogram which initialises a list containing 'star_args'." 1148 1149 if not hasattr(invocation, "stars"): 1150 invocation.stars = {} 1151 1152 if not invocation.stars.has_key(subprogram.full_name()): 1153 code=[ 1154 StoreTemp( 1155 expr=InvokeFunction( 1156 expr=LoadAttr( 1157 expr=LoadRef( 1158 ref=self.builtins 1159 ), 1160 name="list", 1161 nstype="module", 1162 ), 1163 args=[], 1164 star=None, 1165 dstar=None 1166 ) 1167 ) 1168 ] 1169 1170 for arg in star_args: 1171 code.append( 1172 InvokeFunction( 1173 expr=LoadAttr( 1174 expr=LoadTemp(), 1175 name="append" 1176 ), 1177 args=[arg], 1178 star=None, 1179 dstar=None 1180 ) 1181 ) 1182 1183 code += [ 1184 Return(expr=LoadTemp(release=1)) 1185 ] 1186 1187 invocation.stars[subprogram.full_name()] = InvokeBlock( 1188 produces_result=1, 1189 expr=LoadRef( 1190 ref=Subprogram( 1191 name=None, 1192 returns_value=1, 1193 params=[], 1194 star=None, 1195 dstar=None, 1196 code=code 1197 ) 1198 ) 1199 ) 1200 1201 return invocation.stars[subprogram.full_name()] 1202 1203 def make_dstar_args(self, invocation, subprogram, dstar_args): 1204 1205 """ 1206 Make a subprogram which initialises a dictionary built from the given 1207 'dstar_args'. 1208 """ 1209 1210 if not hasattr(invocation, "dstars"): 1211 invocation.dstars = {} 1212 1213 if not invocation.dstars.has_key(subprogram.full_name()): 1214 code=[ 1215 StoreTemp( 1216 expr=InvokeFunction( 1217 expr=LoadAttr( 1218 expr=LoadRef( 1219 ref=self.builtins 1220 ), 1221 name="dict", 1222 nstype="module", 1223 ) 1224 ) 1225 ) 1226 ] 1227 1228 for arg, value in dstar_args: 1229 1230 # NOTE: Constant not added to table. 1231 1232 constant = Constant(name=repr(arg), value=arg, namespace=Namespace()) 1233 code += [ 1234 StoreTemp( 1235 expr=LoadRef( 1236 ref=constant 1237 ), 1238 index="const" 1239 ), 1240 StoreAttr( 1241 lvalue=LoadTemp( 1242 index="const" 1243 ), 1244 name="__class__", 1245 expr=LoadAttr( 1246 expr=LoadRef( 1247 ref=self.builtins 1248 ), 1249 name=constant.typename, 1250 nstype="module", 1251 ) 1252 ), 1253 InvokeFunction( 1254 expr=LoadAttr( 1255 expr=LoadTemp(), 1256 name="__setitem__" 1257 ), 1258 args=[ 1259 LoadTemp( 1260 index="const", 1261 release=1 1262 ), 1263 value 1264 ] 1265 ) 1266 ] 1267 1268 code += [ 1269 Return(expr=LoadTemp(release=1)) 1270 ] 1271 1272 invocation.dstars[subprogram.full_name()] = InvokeBlock( 1273 produces_result=1, 1274 expr=LoadRef( 1275 ref=Subprogram( 1276 name=None, 1277 returns_value=1, 1278 params=[], 1279 star=None, 1280 dstar=None, 1281 code=code 1282 ) 1283 ) 1284 ) 1285 1286 return invocation.dstars[subprogram.full_name()] 1287 1288 # Namespace-related abstractions. 1289 1290 class Namespace: 1291 1292 """ 1293 A local namespace which may either relate to a genuine set of function 1294 locals or the initialisation of a structure or module. 1295 """ 1296 1297 def __init__(self): 1298 1299 """ 1300 Initialise the namespace with a mapping of local names to possible 1301 types, a list of return values and of possible returned local 1302 namespaces. The namespace also tracks the "current" types and a mapping 1303 of temporary value names to types. 1304 """ 1305 1306 self.names = {} 1307 self.returns = [] 1308 self.return_locals = [] 1309 self.raises = [] 1310 self.temp = {} 1311 self.types = [] 1312 1313 def set_types(self, types): 1314 1315 "Set the current collection of 'types'." 1316 1317 self.types = types 1318 1319 def add(self, name, types): 1320 1321 "Add to the entry with the given 'name' the specified 'types'." 1322 1323 if self.names.has_key(name): 1324 combine(self.names[name], types) 1325 else: 1326 self.store(name, types) 1327 1328 def store(self, name, types): 1329 1330 "Store in (or associate with) the given 'name' the specified 'types'." 1331 1332 self.names[name] = types 1333 1334 __setitem__ = store 1335 1336 def load(self, name): 1337 1338 "Load the types associated with the given 'name'." 1339 1340 return self.names[name] 1341 1342 __getitem__ = load 1343 1344 def revoke(self, name, type): 1345 1346 "Revoke from the entry for the given 'name' the specified 'type'." 1347 1348 new_types = self.names[name][:] 1349 new_types.remove(type) 1350 self.names[name] = new_types 1351 1352 def revoke_exception_type(self, type): 1353 1354 "Revoke the given 'type' from the collection of exception types." 1355 1356 self.raises.remove(type) 1357 1358 def revoke_temp_type(self, index, type): 1359 1360 "Revoke from the temporary variable 'index' the given 'type'." 1361 1362 new_types = self.temp[index][-1][:] 1363 new_types.remove(type) 1364 self.temp[index][-1] = new_types 1365 1366 def merge_namespace(self, namespace, everything=1): 1367 1368 """ 1369 Merge items from the given 'namespace' with this namespace. When the 1370 optional 'everything' parameter is set to a false value (unlike the 1371 default), return values and locals snapshots will not be copied to this 1372 namespace. 1373 """ 1374 1375 self.merge_items(namespace.names.items()) 1376 if everything: 1377 combine(self.returns, namespace.returns) 1378 combine(self.return_locals, namespace.return_locals) 1379 combine(self.raises, namespace.raises) 1380 for name, values in namespace.temp.items(): 1381 if values: 1382 if not self.temp.has_key(name) or not self.temp[name]: 1383 self.temp[name] = [[]] 1384 combine(self.temp[name][-1], values[-1]) 1385 1386 def merge_items(self, items): 1387 1388 "Merge the given 'items' with this namespace." 1389 1390 for name, types in items: 1391 self.merge(name, types) 1392 1393 def merge(self, name, types): 1394 1395 "Merge the entry for the given 'name' and 'types' with this namespace." 1396 1397 if not self.names.has_key(name): 1398 self.names[name] = types[:] 1399 else: 1400 existing = self.names[name] 1401 combine(existing, types) 1402 1403 def snapshot(self): 1404 1405 "Make a snapshot of the locals and remember them." 1406 1407 namespace = Namespace() 1408 namespace.merge_namespace(self) 1409 self.return_locals.append(namespace) 1410 1411 def reset(self): 1412 1413 "Reset a namespace in preparation for merging with returned locals." 1414 1415 self.names = {} 1416 1417 def __repr__(self): 1418 return repr(self.names) 1419 1420 class Attribute: 1421 1422 """ 1423 An attribute abstraction, indicating the type of the attribute along with 1424 its context or origin. 1425 """ 1426 1427 def __init__(self, context, type): 1428 self.context = context 1429 self.type = type 1430 1431 def __eq__(self, other): 1432 return hasattr(other, "type") and other.type == self.type or other == self.type 1433 1434 def __repr__(self): 1435 return "Attribute(%s, %s)" % (repr(self.context), repr(self.type)) 1436 1437 class Self: 1438 1439 """ 1440 A program node encapsulating object/context information in an argument list. 1441 This is not particularly like Attribute, Class, Instance or other such 1442 things, since it actually appears in the program representation. 1443 """ 1444 1445 def __init__(self, attribute): 1446 self.types = [attribute] 1447 1448 class Importer: 1449 1450 "An import machine, searching for and loading modules." 1451 1452 def __init__(self, path=None): 1453 1454 """ 1455 Initialise the importer with the given search 'path' - a list of 1456 directories to search for Python modules. 1457 """ 1458 1459 self.path = path or [os.getcwd()] 1460 self.modules = {} 1461 1462 def find_in_path(self, name): 1463 1464 """ 1465 Find the given module 'name' in the search path, returning None where no 1466 such module could be found, or a 2-tuple from the 'find' method 1467 otherwise. 1468 """ 1469 1470 for d in self.path: 1471 m = self.find(d, name) 1472 if m: return m 1473 return None 1474 1475 def find(self, d, name): 1476 1477 """ 1478 In the directory 'd', find the given module 'name', where 'name' can 1479 either refer to a single file module or to a package. Return None if the 1480 'name' cannot be associated with either a file or a package directory, 1481 or a 2-tuple from '_find_package' or '_find_module' otherwise. 1482 """ 1483 1484 m = self._find_package(d, name) 1485 if m: return m 1486 m = self._find_module(d, name) 1487 if m: return m 1488 return None 1489 1490 def _find_module(self, d, name): 1491 1492 """ 1493 In the directory 'd', find the given module 'name', returning None where 1494 no suitable file exists in the directory, or a 2-tuple consisting of 1495 None (indicating that no package directory is involved) and a filename 1496 indicating the location of the module. 1497 """ 1498 1499 name_py = name + os.extsep + "py" 1500 filename = self._find_file(d, name_py) 1501 if filename: 1502 return None, filename 1503 return None 1504 1505 def _find_package(self, d, name): 1506 1507 """ 1508 In the directory 'd', find the given package 'name', returning None 1509 where no suitable package directory exists, or a 2-tuple consisting of 1510 a directory (indicating the location of the package directory itself) 1511 and a filename indicating the location of the __init__.py module which 1512 declares the package's top-level contents. 1513 """ 1514 1515 filename = self._find_file(d, name) 1516 if filename: 1517 init_py = "__init__" + os.path.extsep + "py" 1518 init_py_filename = self._find_file(filename, init_py) 1519 if init_py_filename: 1520 return filename, init_py_filename 1521 return None 1522 1523 def _find_file(self, d, filename): 1524 1525 """ 1526 Return the filename obtained when searching the directory 'd' for the 1527 given 'filename', or None if no actual file exists for the filename. 1528 """ 1529 1530 filename = os.path.join(d, filename) 1531 if os.path.exists(filename): 1532 return filename 1533 else: 1534 return None 1535 1536 def load(self, name, builtins, alias=None): 1537 1538 """ 1539 Load the module or package with the given 'name' and using the specified 1540 'builtins'. Return an Attribute object referencing the loaded module or 1541 package, or None if no such module or package exists. 1542 """ 1543 1544 path = name.split(".") 1545 m = self.find_in_path(path[0]) 1546 if not m: 1547 return None # NOTE: Import error. 1548 d, filename = m 1549 top = module = self.modules.get(path[0], load(filename, builtins, path[0], self)) 1550 self.modules[path[0]] = module 1551 1552 if len(path) > 1: 1553 path_so_far = path[:1] 1554 for p in path[1:]: 1555 path_so_far.append(p) 1556 m = self.find(d, p) 1557 if not m: 1558 return None # NOTE: Import error. 1559 d, filename = m 1560 module_name = ".".join(path_so_far) 1561 submodule = self.modules.get(module_name, load(filename, builtins, module_name, self)) 1562 self.modules[module_name] = submodule 1563 1564 # Store the submodule within its parent module. 1565 1566 module.namespace[p] = [Attribute(None, submodule)] 1567 module = submodule 1568 1569 if alias: 1570 return Attribute(None, module) 1571 else: 1572 return Attribute(None, top) 1573 1574 def combine(target, additions): 1575 1576 """ 1577 Merge into the 'target' sequence the given 'additions', preventing duplicate 1578 items. 1579 """ 1580 1581 for addition in additions: 1582 if addition not in target: 1583 target.append(addition) 1584 1585 def find_attributes(structure, name): 1586 1587 """ 1588 Find for the given 'structure' all attributes for the given 'name', visiting 1589 base classes where appropriate and returning the attributes in order of 1590 descending precedence for all possible base classes. 1591 1592 The elements in the result list are 2-tuples which contain the attribute and 1593 the structure involved in accessing the attribute. 1594 """ 1595 1596 # First attempt to search the instance/class namespace. 1597 1598 try: 1599 l = structure.namespace.load(name) 1600 attributes = [] 1601 for attribute in l: 1602 attributes.append((attribute, structure)) 1603 1604 # If that does not work, attempt to investigate any class or base classes. 1605 1606 except KeyError: 1607 attributes = [] 1608 1609 # Investigate any instance's implementing class. 1610 1611 if isinstance(structure, Instance): 1612 for attr in structure.namespace.load("__class__"): 1613 cls = attr.type 1614 l = get_attributes(cls, name) 1615 combine(attributes, l) 1616 1617 # Investigate any class's base classes. 1618 1619 elif isinstance(structure, Class): 1620 1621 # If no base classes exist, return an indicator that no attribute 1622 # exists. 1623 1624 if not structure.base_refs: 1625 return [(None, structure)] 1626 1627 # Otherwise, find all possible base classes. 1628 1629 for base_refs in structure.base_refs: 1630 base_attributes = [] 1631 1632 # For each base class, find attributes either in the base 1633 # class or its own base classes. 1634 1635 for base_ref in base_refs: 1636 l = get_attributes(base_ref, name) 1637 combine(base_attributes, l) 1638 1639 combine(attributes, base_attributes) 1640 1641 return attributes 1642 1643 def get_attributes(structure, name): 1644 1645 """ 1646 Return all possible attributes for the given 'structure' having the given 1647 'name', wrapping each attribute in an Attribute object which includes 1648 context information for the attribute access. 1649 1650 The elements in the result list are 2-tuples which contain the attribute and 1651 the structure involved in accessing the attribute. 1652 """ 1653 1654 if isinstance(structure, Attribute): 1655 structure = structure.type 1656 results = [] 1657 for attribute, accessor in find_attributes(structure, name): 1658 if attribute is not None and isinstance(structure, Structure): 1659 results.append((Attribute(structure, attribute.type), accessor)) 1660 else: 1661 results.append((attribute, accessor)) 1662 return results 1663 1664 # Convenience functions. 1665 1666 def load(name, builtins=None, module_name=None, importer=None): 1667 1668 """ 1669 Load the module with the given 'name' (which may be a full module path), 1670 using the optional 'builtins' to resolve built-in names, and using the 1671 optional 'importer' to provide a means of finding and loading modules. 1672 """ 1673 1674 module = simplify.simplify(name, builtins is None, module_name) 1675 fixnames.fix(module, builtins) 1676 annotate(module, builtins, importer) 1677 return module 1678 1679 def annotate(module, builtins=None, importer=None): 1680 1681 """ 1682 Annotate the given 'module', also employing the optional 'builtins' module, 1683 if specified. If the optional 'importer' is given, use that to find and load 1684 modules. 1685 """ 1686 1687 annotator = Annotator(importer) 1688 if builtins is not None: 1689 annotator.process(module, builtins) 1690 else: 1691 annotator.process(module) 1692 1693 # vim: tabstop=4 expandtab shiftwidth=4