1 #!/usr/bin/env python 2 3 """ 4 Inspect and obtain module structure. 5 6 Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013, 7 2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk> 8 9 This program is free software; you can redistribute it and/or modify it under 10 the terms of the GNU General Public License as published by the Free Software 11 Foundation; either version 3 of the License, or (at your option) any later 12 version. 13 14 This program is distributed in the hope that it will be useful, but WITHOUT 15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 16 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 17 details. 18 19 You should have received a copy of the GNU General Public License along with 20 this program. If not, see <http://www.gnu.org/licenses/>. 21 """ 22 23 from branching import BranchTracker 24 from common import get_argnames, init_item, predefined_constants 25 from modules import BasicModule, CacheWritingModule, InspectionNaming 26 from errors import InspectError 27 from referencing import Reference 28 from resolving import NameResolving 29 from results import AccessRef, InstanceRef, InvocationRef, LiteralSequenceRef, \ 30 LocalNameRef, NameRef, ResolvedNameRef 31 import compiler 32 import sys 33 34 class InspectedModule(BasicModule, CacheWritingModule, NameResolving, InspectionNaming): 35 36 "A module inspector." 37 38 def __init__(self, name, importer): 39 40 "Initialise the module with basic details." 41 42 BasicModule.__init__(self, name, importer) 43 44 self.in_class = False 45 self.in_conditional = False 46 self.global_attr_accesses = {} 47 48 # Usage tracking. 49 50 self.trackers = [] 51 self.attr_accessor_branches = {} 52 53 def __repr__(self): 54 return "InspectedModule(%r, %r)" % (self.name, self.importer) 55 56 # Principal methods. 57 58 def parse(self, filename): 59 60 "Parse the file having the given 'filename'." 61 62 self.parse_file(filename) 63 64 # Inspect the module. 65 66 self.start_tracking_in_module() 67 68 # Detect and record imports and globals declared in the module. 69 70 self.assign_general_local("__name__", self.get_constant("str", self.name)) 71 self.assign_general_local("__file__", self.get_constant("str", filename)) 72 self.process_structure(self.astnode) 73 74 # Set the class of the module after the definition has occurred. 75 76 ref = self.get_builtin("object") 77 self.set_name("__class__", ref) 78 79 # Get module-level attribute usage details. 80 81 self.stop_tracking_in_module() 82 83 # Collect external name references. 84 85 self.collect_names() 86 87 def complete(self): 88 89 "Complete the module inspection." 90 91 # Resolve names not definitively mapped to objects. 92 93 self.resolve() 94 95 # Define the invocation requirements in each namespace. 96 97 self.set_invocation_usage() 98 99 # Propagate to the importer information needed in subsequent activities. 100 101 self.propagate() 102 103 # Accessory methods. 104 105 def collect_names(self): 106 107 "Collect the names used by each scope." 108 109 for path in self.names_used.keys(): 110 self.collect_names_for_path(path) 111 112 def collect_names_for_path(self, path): 113 114 """ 115 Collect the names used by the given 'path'. These are propagated to the 116 importer in advance of any dependency resolution. 117 """ 118 119 names = self.names_used.get(path) 120 if not names: 121 return 122 123 in_function = self.function_locals.has_key(path) 124 125 for name in names: 126 if name in predefined_constants or in_function and name in self.function_locals[path]: 127 continue 128 129 # Find local definitions (within dynamic namespaces). 130 131 key = "%s.%s" % (path, name) 132 ref = self.get_resolved_object(key) 133 if ref: 134 self.set_name_reference(key, ref) 135 continue 136 137 # Find global or known built-in definitions. 138 139 ref = self.get_resolved_global_or_builtin(name) 140 if ref: 141 self.set_name_reference(key, ref) 142 continue 143 144 # Find presumed built-in definitions. 145 146 ref = self.get_builtin(name) 147 self.set_name_reference(key, ref) 148 149 def set_name_reference(self, path, ref): 150 151 "Map the given name 'path' to 'ref'." 152 153 self.importer.all_name_references[path] = self.name_references[path] = ref 154 155 def get_resolved_global_or_builtin(self, name): 156 157 "Return the resolved global or built-in object with the given 'name'." 158 159 # In some circumstances, the name is neither global nor recognised by 160 # the importer. It is then assumed to be a general built-in. 161 162 return self.get_global(name) or \ 163 self.importer.get_object("__builtins__.%s" % name) 164 165 # Module structure traversal. 166 167 def process_structure_node(self, n): 168 169 "Process the individual node 'n'." 170 171 # Module global detection. 172 173 if isinstance(n, compiler.ast.Global): 174 self.process_global_node(n) 175 176 # Module import declarations. 177 178 elif isinstance(n, compiler.ast.From): 179 self.process_from_node(n) 180 181 elif isinstance(n, compiler.ast.Import): 182 self.process_import_node(n) 183 184 # Nodes using operator module functions. 185 186 elif isinstance(n, compiler.ast.Operator): 187 return self.process_operator_node(n) 188 189 elif isinstance(n, compiler.ast.AugAssign): 190 self.process_augassign_node(n) 191 192 elif isinstance(n, compiler.ast.Compare): 193 return self.process_compare_node(n) 194 195 elif isinstance(n, compiler.ast.Slice): 196 return self.process_slice_node(n) 197 198 elif isinstance(n, compiler.ast.Sliceobj): 199 return self.process_sliceobj_node(n) 200 201 elif isinstance(n, compiler.ast.Subscript): 202 return self.process_subscript_node(n) 203 204 # Namespaces within modules. 205 206 elif isinstance(n, compiler.ast.Class): 207 self.process_class_node(n) 208 209 elif isinstance(n, compiler.ast.Function): 210 self.process_function_node(n, n.name) 211 212 elif isinstance(n, compiler.ast.Lambda): 213 return self.process_lambda_node(n) 214 215 # Assignments. 216 217 elif isinstance(n, compiler.ast.Assign): 218 219 # Handle each assignment node. 220 221 for node in n.nodes: 222 self.process_assignment_node(node, n.expr) 223 224 # Assignments within non-Assign nodes. 225 226 elif isinstance(n, compiler.ast.AssName): 227 self.process_assignment_node(n, None) 228 229 elif isinstance(n, compiler.ast.AssAttr): 230 self.process_attribute_access(n) 231 232 # Accesses. 233 234 elif isinstance(n, compiler.ast.Getattr): 235 return self.process_attribute_access(n) 236 237 # Name recording for later testing. 238 239 elif isinstance(n, compiler.ast.Name): 240 return self.process_name_node(n) 241 242 # Conditional statement tracking. 243 244 elif isinstance(n, compiler.ast.For): 245 self.process_for_node(n) 246 247 elif isinstance(n, compiler.ast.While): 248 self.process_while_node(n) 249 250 elif isinstance(n, compiler.ast.If): 251 self.process_if_node(n) 252 253 elif isinstance(n, (compiler.ast.And, compiler.ast.Or)): 254 return self.process_logical_node(n) 255 256 # Exception control-flow tracking. 257 258 elif isinstance(n, compiler.ast.TryExcept): 259 self.process_try_node(n) 260 261 elif isinstance(n, compiler.ast.TryFinally): 262 self.process_try_finally_node(n) 263 264 # Control-flow modification statements. 265 266 elif isinstance(n, compiler.ast.Break): 267 self.trackers[-1].suspend_broken_branch() 268 269 elif isinstance(n, compiler.ast.Continue): 270 self.trackers[-1].suspend_continuing_branch() 271 272 elif isinstance(n, compiler.ast.Raise): 273 self.process_structure(n) 274 self.trackers[-1].abandon_branch() 275 276 elif isinstance(n, compiler.ast.Return): 277 self.process_structure(n) 278 self.trackers[-1].abandon_returning_branch() 279 280 # Invocations. 281 282 elif isinstance(n, compiler.ast.CallFunc): 283 return self.process_invocation_node(n) 284 285 # Constant usage. 286 287 elif isinstance(n, compiler.ast.Const): 288 return self.get_literal_instance(n, n.value.__class__.__name__) 289 290 elif isinstance(n, compiler.ast.Dict): 291 return self.get_literal_instance(n, "dict") 292 293 elif isinstance(n, compiler.ast.List): 294 return self.get_literal_instance(n, "list") 295 296 elif isinstance(n, compiler.ast.Tuple): 297 return self.get_literal_instance(n, "tuple") 298 299 # Unsupported nodes. 300 301 elif isinstance(n, compiler.ast.GenExpr): 302 raise InspectError("Generator expressions are not supported.", self.get_namespace_path(), n) 303 304 elif isinstance(n, compiler.ast.IfExp): 305 raise InspectError("If-else expressions are not supported.", self.get_namespace_path(), n) 306 307 elif isinstance(n, compiler.ast.ListComp): 308 raise InspectError("List comprehensions are not supported.", self.get_namespace_path(), n) 309 310 # All other nodes are processed depth-first. 311 312 else: 313 self.process_structure(n) 314 315 # By default, no expression details are returned. 316 317 return None 318 319 # Specific node handling. 320 321 def process_assignment_node(self, n, expr): 322 323 "Process the individual node 'n' to be assigned the contents of 'expr'." 324 325 # Names and attributes are assigned the entire expression. 326 327 if isinstance(n, compiler.ast.AssName): 328 329 name_ref = expr and self.process_structure_node(expr) 330 331 # Name assignments populate either function namespaces or the 332 # general namespace hierarchy. 333 334 self.assign_general_local(n.name, name_ref) 335 336 # Record usage of the name. 337 338 self.record_name(n.name) 339 340 elif isinstance(n, compiler.ast.AssAttr): 341 if expr: self.process_structure_node(expr) 342 self.process_attribute_access(n) 343 344 # Lists and tuples are matched against the expression and their 345 # items assigned to expression items. 346 347 elif isinstance(n, (compiler.ast.AssList, compiler.ast.AssTuple)): 348 self.process_assignment_node_items(n, expr) 349 350 # Slices and subscripts are permitted within assignment nodes. 351 352 elif isinstance(n, compiler.ast.Slice): 353 self.process_slice_node(n, expr) 354 355 elif isinstance(n, compiler.ast.Subscript): 356 self.process_subscript_node(n, expr) 357 358 def process_attribute_access(self, n): 359 360 "Process the given attribute access node 'n'." 361 362 # Obtain any completed chain and return the reference to it. 363 364 name_ref = self.process_attribute_chain(n) 365 if self.have_access_expression(n): 366 return name_ref 367 368 # Where the start of the chain of attributes has been reached, determine 369 # the complete access. 370 371 # Given a non-access node, this chain can be handled in its entirety, 372 # either being name-based and thus an access rooted on a name, or being 373 # based on some other node and thus an anonymous access of some kind. 374 375 path = self.get_namespace_path() 376 377 # Start with the the full attribute chain. 378 379 remaining = self.attrs 380 attrnames = ".".join(remaining) 381 382 # If the accessor cannot be identified, or where attributes 383 # remain in an attribute chain, record the anonymous accesses. 384 385 if not isinstance(name_ref, NameRef): # includes ResolvedNameRef 386 387 assignment = isinstance(n, compiler.ast.AssAttr) 388 389 init_item(self.attr_accesses, path, set) 390 self.attr_accesses[path].add(attrnames) 391 392 self.record_access_details(None, attrnames, assignment) 393 del self.attrs[0] 394 return 395 396 # Name-based accesses will handle the first attribute in a 397 # chain. 398 399 else: 400 attrname = remaining[0] 401 402 # Attribute assignments are used to identify instance attributes. 403 404 if isinstance(n, compiler.ast.AssAttr) and \ 405 self.in_class and self.in_function and n.expr.name == "self": 406 407 self.set_instance_attr(attrname) 408 409 # Record attribute usage using any name local to this namespace, 410 # if assigned in the namespace, or using an external name 411 # (presently just globals within classes). 412 413 name = self.get_name_for_tracking(name_ref.name, name_ref.final()) 414 tracker = self.trackers[-1] 415 416 immediate_access = len(self.attrs) == 1 417 assignment = immediate_access and isinstance(n, compiler.ast.AssAttr) 418 419 del self.attrs[0] 420 421 # Record global-based chains for subsequent resolution. 422 423 is_global = self.in_function and not self.function_locals[path].has_key(name) or \ 424 not self.in_function 425 426 if is_global: 427 self.record_global_access_details(name, attrnames) 428 429 # Make sure the name is being tracked: global names will not 430 # already be initialised in a branch and must be added 431 # explicitly. 432 433 if not tracker.have_name(name): 434 tracker.assign_names([name]) 435 if self.in_function: 436 self.scope_globals[path].add(name) 437 438 # Record attribute usage in the tracker, and record the branch 439 # information for the access. 440 441 branches = tracker.use_attribute(name, attrname) 442 443 if not branches: 444 print >>sys.stderr, "In %s, name %s is accessed using %s before an assignment." % ( 445 path, name, attrname) 446 branches = tracker.use_attribute(name, attrname) 447 448 self.record_branches_for_access(branches, name, attrnames) 449 access_number = self.record_access_details(name, attrnames, assignment) 450 return AccessRef(name, attrnames, access_number) 451 452 def process_class_node(self, n): 453 454 "Process the given class node 'n'." 455 456 path = self.get_namespace_path() 457 458 # To avoid notions of class "versions" where the same definition 459 # might be parameterised with different state and be referenced 460 # elsewhere (as base classes, for example), classes in functions or 461 # conditions are forbidden. 462 463 if self.in_function or self.in_conditional: 464 print >>sys.stderr, "In %s, class %s in function or conditional statement ignored." % ( 465 path, n.name) 466 return 467 468 # Resolve base classes. 469 470 bases = [] 471 472 for base in n.bases: 473 base_class = self.get_class(base) 474 475 if not base_class: 476 print >>sys.stderr, "In %s, class %s has unidentifiable base class: %s" % ( 477 path, n.name, base) 478 return 479 else: 480 bases.append(base_class) 481 482 # Record bases for the class and retain the class name. 483 484 class_name = self.get_object_path(n.name) 485 486 if not bases and class_name != "__builtins__.core.object": 487 ref = self.get_object("__builtins__.object") 488 bases.append(ref) 489 490 self.importer.classes[class_name] = self.classes[class_name] = bases 491 self.importer.subclasses[class_name] = set() 492 self.scope_globals[class_name] = set() 493 494 # Set the definition before entering the namespace rather than 495 # afterwards because methods may reference it. In normal Python, 496 # a class is not accessible until the definition is complete, but 497 # methods can generally reference it since upon being called the 498 # class will already exist. 499 500 self.set_definition(n.name, "<class>") 501 502 in_class = self.in_class 503 self.in_class = class_name 504 self.set_instance_attr("__class__", Reference("<class>", class_name)) 505 self.enter_namespace(n.name) 506 self.set_name("__fn__") # special instantiator attribute 507 self.set_name("__args__") # special instantiator attribute 508 self.assign_general_local("__name__", self.get_constant("str", class_name)) 509 self.process_structure_node(n.code) 510 self.exit_namespace() 511 self.in_class = in_class 512 513 def process_from_node(self, n): 514 515 "Process the given node 'n', importing from another module." 516 517 path = self.get_namespace_path() 518 519 module_name, names = self.get_module_name(n) 520 if module_name == self.name: 521 raise InspectError("Cannot import from the current module.", path, n) 522 523 self.queue_module(module_name) 524 525 # Attempt to obtain the referenced objects. 526 527 for name, alias in n.names: 528 if name == "*": 529 raise InspectError("Only explicitly specified names can be imported from modules.", path, n) 530 531 # Explicit names. 532 533 ref = self.import_name_from_module(name, module_name) 534 value = ResolvedNameRef(alias or name, ref) 535 self.set_general_local(alias or name, value) 536 537 def process_function_node(self, n, name): 538 539 """ 540 Process the given function or lambda node 'n' with the given 'name'. 541 """ 542 543 is_lambda = isinstance(n, compiler.ast.Lambda) 544 545 # Where a function is declared conditionally, use a separate name for 546 # the definition, and assign the definition to the stated name. 547 548 if (self.in_conditional or self.in_function) and not is_lambda: 549 original_name = name 550 name = self.get_lambda_name() 551 else: 552 original_name = None 553 554 # Initialise argument and local records. 555 556 function_name = self.get_object_path(name) 557 argnames = get_argnames(n.argnames) 558 is_method = self.in_class and not self.in_function 559 560 # Remove explicit "self" from method parameters. 561 562 if is_method and argnames and argnames[0] == "self": 563 del argnames[0] 564 565 # Copy and propagate the parameters. 566 567 self.importer.function_parameters[function_name] = \ 568 self.function_parameters[function_name] = argnames[:] 569 570 # Define all arguments/parameters in the local namespace. 571 572 locals = self.function_locals[function_name] = {} 573 574 # Insert "self" into method locals. 575 576 if is_method: 577 argnames.insert(0, "self") 578 579 # Define "self" in terms of the class if in a method. 580 # This does not diminish the need for type-narrowing in the deducer. 581 582 if argnames: 583 if self.in_class and not self.in_function and argnames[0] == "self": 584 locals[argnames[0]] = Reference("<instance>", self.in_class) 585 else: 586 locals[argnames[0]] = Reference("<var>") 587 588 for argname in argnames[1:]: 589 locals[argname] = Reference("<var>") 590 591 globals = self.scope_globals[function_name] = set() 592 593 # Process the defaults. 594 595 defaults = self.importer.function_defaults[function_name] = \ 596 self.function_defaults[function_name] = [] 597 598 for argname, default in compiler.ast.get_defaults(n): 599 if default: 600 601 # Obtain any reference for the default. 602 603 name_ref = self.process_structure_node(default) 604 defaults.append((argname, name_ref.is_name() and name_ref.reference() or Reference("<var>"))) 605 606 # Reset conditional tracking to focus on the function contents. 607 608 in_conditional = self.in_conditional 609 self.in_conditional = False 610 611 in_function = self.in_function 612 self.in_function = function_name 613 614 self.enter_namespace(name) 615 616 # Track attribute usage within the namespace. 617 618 path = self.get_namespace_path() 619 620 self.start_tracking(locals) 621 self.process_structure_node(n.code) 622 self.stop_tracking() 623 624 # Exit to the parent. 625 626 self.exit_namespace() 627 628 # Update flags. 629 630 self.in_function = in_function 631 self.in_conditional = in_conditional 632 633 # Define the function using the appropriate name. 634 635 self.set_definition(name, "<function>") 636 637 # Where a function is set conditionally, assign the name. 638 639 if original_name: 640 self.process_assignment_for_function(original_name, name) 641 642 def process_global_node(self, n): 643 644 """ 645 Process the given "global" node 'n'. 646 """ 647 648 path = self.get_namespace_path() 649 650 if path != self.name: 651 self.scope_globals[path].update(n.names) 652 653 def process_if_node(self, n): 654 655 """ 656 Process the given "if" node 'n'. 657 """ 658 659 tracker = self.trackers[-1] 660 tracker.new_branchpoint() 661 662 for test, body in n.tests: 663 self.process_structure_node(test) 664 665 tracker.new_branch() 666 667 in_conditional = self.in_conditional 668 self.in_conditional = True 669 self.process_structure_node(body) 670 self.in_conditional = in_conditional 671 672 tracker.shelve_branch() 673 674 # Maintain a branch for the else clause. 675 676 tracker.new_branch() 677 if n.else_: 678 self.process_structure_node(n.else_) 679 tracker.shelve_branch() 680 681 tracker.merge_branches() 682 683 def process_import_node(self, n): 684 685 "Process the given import node 'n'." 686 687 path = self.get_namespace_path() 688 689 # Load the mentioned module. 690 691 for name, alias in n.names: 692 if name == self.name: 693 raise InspectError("Cannot import the current module.", path, n) 694 695 self.set_module(alias or name.split(".")[-1], name) 696 self.queue_module(name, True) 697 698 def process_invocation_node(self, n): 699 700 "Process the given invocation node 'n'." 701 702 path = self.get_namespace_path() 703 704 self.allocate_arguments(path, n.args) 705 706 try: 707 # Process the expression, obtaining any identified reference. 708 709 name_ref = self.process_structure_node(n.node) 710 711 # Process the arguments. 712 713 for arg in n.args: 714 self.process_structure_node(arg) 715 716 # Detect class invocations. 717 718 if isinstance(name_ref, ResolvedNameRef) and name_ref.has_kind("<class>"): 719 return InstanceRef(name_ref.reference().instance_of()) 720 721 elif isinstance(name_ref, NameRef): 722 return InvocationRef(name_ref) 723 724 return None 725 726 finally: 727 self.deallocate_arguments(path, n.args) 728 729 def process_lambda_node(self, n): 730 731 "Process the given lambda node 'n'." 732 733 name = self.get_lambda_name() 734 self.process_function_node(n, name) 735 736 origin = self.get_object_path(name) 737 return ResolvedNameRef(name, Reference("<function>", origin)) 738 739 def process_logical_node(self, n): 740 741 "Process the given operator node 'n'." 742 743 self.process_operator_chain(n.nodes, self.process_structure_node) 744 745 def process_name_node(self, n): 746 747 "Process the given name node 'n'." 748 749 path = self.get_namespace_path() 750 751 # Special names. 752 753 if n.name.startswith("$"): 754 value = self.get_special(n.name) 755 if value: 756 return value 757 758 # Special case for operator functions introduced through code 759 # transformations. 760 761 if n.name.startswith("$op"): 762 763 # Obtain the location of the actual function defined in the operator 764 # package. 765 766 op = n.name[len("$op"):] 767 768 # Attempt to get a reference. 769 770 ref = self.import_name_from_module(op, "operator") 771 self.add_deferred(ref) 772 773 # Record the imported name and provide the resolved name reference. 774 775 value = ResolvedNameRef(n.name, ref) 776 self.set_special(n.name, value) 777 return value 778 779 # Record usage of the name. 780 781 self.record_name(n.name) 782 783 # Search for unknown names in non-function scopes immediately. 784 # External names in functions are resolved later. 785 786 ref = self.find_name(n.name) 787 if ref: 788 return ResolvedNameRef(n.name, ref) 789 790 # Explicitly-declared global names. 791 792 elif self.in_function and n.name in self.scope_globals[path]: 793 return NameRef(n.name) 794 795 # Examine other names. 796 797 else: 798 tracker = self.trackers[-1] 799 800 # Check local names. 801 802 branches = tracker.tracking_name(n.name) 803 804 # Local name. 805 806 if branches: 807 self.record_branches_for_access(branches, n.name, None) 808 access_number = self.record_access_details(n.name, None, False) 809 return LocalNameRef(n.name, access_number) 810 811 # Possible global or built-in name. 812 813 else: 814 return NameRef(n.name) 815 816 def process_operator_chain(self, nodes, fn): 817 818 """ 819 Process the given chain of 'nodes', applying 'fn' to each node or item. 820 Each node starts a new conditional region, effectively making a deeply- 821 nested collection of if-like statements. 822 """ 823 824 tracker = self.trackers[-1] 825 826 for item in nodes: 827 tracker.new_branchpoint() 828 tracker.new_branch() 829 fn(item) 830 831 for item in nodes[:-1]: 832 tracker.shelve_branch() 833 tracker.new_branch() 834 tracker.shelve_branch() 835 tracker.merge_branches() 836 837 tracker.shelve_branch() 838 tracker.merge_branches() 839 840 def process_try_node(self, n): 841 842 """ 843 Process the given "try...except" node 'n'. 844 """ 845 846 tracker = self.trackers[-1] 847 tracker.new_branchpoint() 848 849 self.process_structure_node(n.body) 850 851 for name, var, handler in n.handlers: 852 if name is not None: 853 self.process_structure_node(name) 854 855 # Any abandoned branches from the body can now be resumed in a new 856 # branch. 857 858 tracker.resume_abandoned_branches() 859 860 # Establish the local for the handler. 861 862 if var is not None: 863 self.process_structure_node(var) 864 if handler is not None: 865 self.process_structure_node(handler) 866 867 tracker.shelve_branch() 868 869 # The else clause maintains the usage from the body but without the 870 # abandoned branches since they would never lead to the else clause 871 # being executed. 872 873 if n.else_: 874 tracker.new_branch() 875 self.process_structure_node(n.else_) 876 tracker.shelve_branch() 877 878 # Without an else clause, a null branch propagates the successful 879 # outcome. 880 881 else: 882 tracker.new_branch() 883 tracker.shelve_branch() 884 885 tracker.merge_branches() 886 887 def process_try_finally_node(self, n): 888 889 """ 890 Process the given "try...finally" node 'n'. 891 """ 892 893 tracker = self.trackers[-1] 894 self.process_structure_node(n.body) 895 896 # Any abandoned branches from the body can now be resumed. 897 898 branches = tracker.resume_all_abandoned_branches() 899 self.process_structure_node(n.final) 900 901 # At the end of the finally clause, abandoned branches are discarded. 902 903 tracker.restore_active_branches(branches) 904 905 def process_while_node(self, n): 906 907 "Process the given while node 'n'." 908 909 tracker = self.trackers[-1] 910 tracker.new_branchpoint(loop_node=True) 911 912 # Evaluate any test or iterator outside the loop. 913 914 self.process_structure_node(n.test) 915 916 # Propagate attribute usage to branches. 917 918 tracker.new_branch(loop_node=True) 919 920 # Enter the loop. 921 922 in_conditional = self.in_conditional 923 self.in_conditional = True 924 self.process_structure_node(n.body) 925 self.in_conditional = in_conditional 926 927 # Continuing branches are resumed before any test. 928 929 tracker.resume_continuing_branches() 930 931 # Evaluate any continuation test within the body. 932 933 self.process_structure_node(n.test) 934 935 tracker.shelve_branch(loop_node=True) 936 937 # Support the non-looping condition. 938 939 tracker.new_branch() 940 tracker.shelve_branch() 941 942 tracker.merge_branches() 943 944 # Evaluate any else clause outside branches. 945 946 if n.else_: 947 self.process_structure_node(n.else_) 948 949 # Connect broken branches to the code after any loop. 950 951 tracker.resume_broken_branches() 952 953 # Branch tracking methods. 954 955 def start_tracking(self, names): 956 957 """ 958 Start tracking attribute usage for names in the current namespace, 959 immediately registering the given 'names'. 960 """ 961 962 path = self.get_namespace_path() 963 parent = self.trackers[-1] 964 tracker = BranchTracker() 965 self.trackers.append(tracker) 966 967 # Record the given names established as new branches. 968 969 tracker.assign_names(names) 970 971 def assign_name(self, name, name_ref): 972 973 "Assign to 'name' the given 'name_ref' in the current namespace." 974 975 name = self.get_name_for_tracking(name) 976 self.trackers[-1].assign_names([name], [name_ref]) 977 978 def stop_tracking(self): 979 980 """ 981 Stop tracking attribute usage, recording computed usage for the current 982 namespace. 983 """ 984 985 path = self.get_namespace_path() 986 tracker = self.trackers.pop() 987 self.record_assignments_for_access(tracker) 988 989 self.attr_usage[path] = tracker.get_all_usage() 990 self.name_initialisers[path] = tracker.get_all_values() 991 992 def start_tracking_in_module(self): 993 994 "Start tracking attribute usage in the module." 995 996 tracker = BranchTracker() 997 self.trackers.append(tracker) 998 999 def stop_tracking_in_module(self): 1000 1001 "Stop tracking attribute usage in the module." 1002 1003 tracker = self.trackers[0] 1004 self.record_assignments_for_access(tracker) 1005 self.attr_usage[self.name] = tracker.get_all_usage() 1006 self.name_initialisers[self.name] = tracker.get_all_values() 1007 1008 def record_assignments_for_access(self, tracker): 1009 1010 """ 1011 For the current path, use the given 'tracker' to record assignment 1012 version information for attribute accesses. 1013 """ 1014 1015 path = self.get_path_for_access() 1016 1017 if not self.attr_accessor_branches.has_key(path): 1018 return 1019 1020 init_item(self.attr_accessors, path, dict) 1021 attr_accessors = self.attr_accessors[path] 1022 1023 # Obtain the branches applying during each access. 1024 1025 for access, all_branches in self.attr_accessor_branches[path].items(): 1026 name, attrnames = access 1027 init_item(attr_accessors, access, list) 1028 1029 # Obtain the assignments applying to each branch. 1030 1031 for branches in all_branches: 1032 positions = tracker.get_assignment_positions_for_branches(name, branches) 1033 1034 # Detect missing name information. 1035 1036 if None in positions: 1037 globals = self.global_attr_accesses.get(path) 1038 accesses = globals and globals.get(name) 1039 if not accesses: 1040 print >>sys.stderr, "In %s, %s may not be defined when used." % ( 1041 self.get_namespace_path(), name) 1042 positions.remove(None) 1043 1044 attr_accessors[access].append(positions) 1045 1046 def record_branches_for_access(self, branches, name, attrnames): 1047 1048 """ 1049 Record the given 'branches' for an access involving the given 'name' and 1050 'attrnames'. 1051 """ 1052 1053 access = name, attrnames 1054 path = self.get_path_for_access() 1055 1056 init_item(self.attr_accessor_branches, path, dict) 1057 attr_accessor_branches = self.attr_accessor_branches[path] 1058 1059 init_item(attr_accessor_branches, access, list) 1060 attr_accessor_branches[access].append(branches) 1061 1062 def record_access_details(self, name, attrnames, assignment): 1063 1064 """ 1065 For the given 'name' and 'attrnames', record an access indicating 1066 whether 'assignment' is occurring. 1067 1068 These details correspond to accesses otherwise recorded by the attribute 1069 accessor and attribute access dictionaries. 1070 """ 1071 1072 access = name, attrnames 1073 path = self.get_path_for_access() 1074 1075 init_item(self.attr_access_modifiers, path, dict) 1076 init_item(self.attr_access_modifiers[path], access, list) 1077 1078 access_number = len(self.attr_access_modifiers[path][access]) 1079 self.attr_access_modifiers[path][access].append(assignment) 1080 return access_number 1081 1082 def record_global_access_details(self, name, attrnames): 1083 1084 """ 1085 Record details of a global access via the given 'name' involving the 1086 indicated 'attrnames'. 1087 """ 1088 1089 path = self.get_namespace_path() 1090 1091 init_item(self.global_attr_accesses, path, dict) 1092 init_item(self.global_attr_accesses[path], name, set) 1093 self.global_attr_accesses[path][name].add(attrnames) 1094 1095 # Namespace modification. 1096 1097 def record_name(self, name): 1098 1099 "Record the use of 'name' in a namespace." 1100 1101 path = self.get_namespace_path() 1102 init_item(self.names_used, path, set) 1103 self.names_used[path].add(name) 1104 1105 def set_module(self, name, module_name): 1106 1107 """ 1108 Set a module in the current namespace using the given 'name' associated 1109 with the corresponding 'module_name'. 1110 """ 1111 1112 if name: 1113 self.set_general_local(name, Reference("<module>", module_name)) 1114 1115 def set_definition(self, name, kind): 1116 1117 """ 1118 Set the definition having the given 'name' and 'kind'. 1119 1120 Definitions are set in the static namespace hierarchy, but they can also 1121 be recorded for function locals. 1122 """ 1123 1124 if self.is_global(name): 1125 print >>sys.stderr, "In %s, %s is defined as being global." % ( 1126 self.get_namespace_path(), name) 1127 1128 path = self.get_object_path(name) 1129 self.set_object(path, kind) 1130 1131 ref = self.get_object(path) 1132 if ref.get_kind() == "<var>": 1133 print >>sys.stderr, "In %s, %s is defined more than once." % ( 1134 self.get_namespace_path(), name) 1135 1136 if not self.is_global(name) and self.in_function: 1137 self.set_function_local(name, ref) 1138 1139 def set_function_local(self, name, ref=None): 1140 1141 "Set the local with the given 'name' and optional 'ref'." 1142 1143 locals = self.function_locals[self.get_namespace_path()] 1144 multiple = not ref or locals.has_key(name) and locals[name] != ref 1145 locals[name] = multiple and Reference("<var>") or ref 1146 1147 def assign_general_local(self, name, name_ref): 1148 1149 """ 1150 Set for 'name' the given 'name_ref', recording the name for attribute 1151 usage tracking. 1152 """ 1153 1154 self.set_general_local(name, name_ref) 1155 self.assign_name(name, name_ref) 1156 1157 def set_general_local(self, name, value=None): 1158 1159 """ 1160 Set the 'name' with optional 'value' in any kind of local namespace, 1161 where the 'value' should be a reference if specified. 1162 """ 1163 1164 init_value = self.get_initialising_value(value) 1165 1166 # Module global names. 1167 1168 if self.is_global(name): 1169 path = self.get_global_path(name) 1170 self.set_object(path, init_value) 1171 1172 # Function local names. 1173 1174 elif self.in_function: 1175 path = self.get_object_path(name) 1176 self.set_function_local(name, init_value) 1177 1178 # Other namespaces (classes). 1179 1180 else: 1181 path = self.get_object_path(name) 1182 self.set_name(name, init_value) 1183 1184 def set_name(self, name, ref=None): 1185 1186 "Attach the 'name' with optional 'ref' to the current namespace." 1187 1188 self.set_object(self.get_object_path(name), ref) 1189 1190 def set_instance_attr(self, name, ref=None): 1191 1192 """ 1193 Add an instance attribute of the given 'name' to the current class, 1194 using the optional 'ref'. 1195 """ 1196 1197 init_item(self.instance_attrs, self.in_class, set) 1198 self.instance_attrs[self.in_class].add(name) 1199 1200 if ref: 1201 init_item(self.instance_attr_constants, self.in_class, dict) 1202 self.instance_attr_constants[self.in_class][name] = ref 1203 1204 def get_initialising_value(self, value): 1205 1206 "Return a suitable initialiser reference for 'value'." 1207 1208 # Includes LiteralSequenceRef, ResolvedNameRef... 1209 1210 if isinstance(value, (NameRef, AccessRef, InstanceRef)): 1211 return value.reference() 1212 1213 # In general, invocations do not produce known results. However, the 1214 # name initialisers are resolved once a module has been inspected. 1215 1216 elif isinstance(value, InvocationRef): 1217 return value.reference() 1218 1219 else: 1220 return value 1221 1222 # Static, program-relative naming. 1223 1224 def find_name(self, name): 1225 1226 """ 1227 Return the qualified name for the given 'name' used in the current 1228 non-function namespace. 1229 """ 1230 1231 path = self.get_namespace_path() 1232 ref = None 1233 1234 if not self.in_function and name not in predefined_constants: 1235 if self.in_class: 1236 ref = self.get_object(self.get_object_path(name)) 1237 if not ref: 1238 ref = self.get_global_or_builtin(name) 1239 1240 return ref 1241 1242 def get_class(self, node): 1243 1244 """ 1245 Use the given 'node' to obtain the identity of a class. Return a 1246 reference for the class. Unresolved dependencies are permitted and must 1247 be resolved later. 1248 """ 1249 1250 ref = self._get_class(node) 1251 return ref.has_kind(["<class>", "<depends>"]) and ref or None 1252 1253 def _get_class(self, node): 1254 1255 """ 1256 Use the given 'node' to find a class definition. Return a reference to 1257 the class. 1258 """ 1259 1260 if isinstance(node, compiler.ast.Getattr): 1261 1262 # Obtain the identity of the access target. 1263 1264 ref = self._get_class(node.expr) 1265 1266 # Where the target is a class or module, obtain the identity of the 1267 # attribute. 1268 1269 if ref.has_kind(["<function>", "<var>"]): 1270 return None 1271 else: 1272 attrname = "%s.%s" % (ref.get_origin(), node.attrname) 1273 return self.get_object(attrname) 1274 1275 # Names can be module-level or built-in. 1276 1277 elif isinstance(node, compiler.ast.Name): 1278 1279 # Record usage of the name and attempt to identify it. 1280 1281 self.record_name(node.name) 1282 return self.get_global_or_builtin(node.name) 1283 else: 1284 return None 1285 1286 def get_constant(self, name, value): 1287 1288 "Return a constant reference for the given type 'name' and 'value'." 1289 1290 ref = self.get_builtin_class(name) 1291 return self.get_constant_reference(ref, value) 1292 1293 def get_literal_instance(self, n, name): 1294 1295 "For node 'n', return a reference to an instance of 'name'." 1296 1297 # Get a reference to the built-in class. 1298 1299 ref = self.get_builtin_class(name) 1300 1301 # Obtain the details of the literal itself. 1302 # An alias to the type is generated for sequences. 1303 1304 if name in ("dict", "list", "tuple"): 1305 self.set_special_literal(name, ref) 1306 return self.process_literal_sequence_node(n, name, ref, LiteralSequenceRef) 1307 1308 # Constant values are independently recorded. 1309 1310 else: 1311 return self.get_constant_reference(ref, n.value) 1312 1313 # Special names. 1314 1315 def get_special(self, name): 1316 1317 "Return any stored value for the given special 'name'." 1318 1319 return self.special.get(name) 1320 1321 def set_special(self, name, value): 1322 1323 """ 1324 Set a special 'name' that merely tracks the use of an implicit object 1325 'value'. 1326 """ 1327 1328 self.special[name] = value 1329 1330 def set_special_literal(self, name, ref): 1331 1332 """ 1333 Set a special name for the literal type 'name' having type 'ref'. Such 1334 special names provide a way of referring to literal object types. 1335 """ 1336 1337 literal_name = "$L%s" % name 1338 value = ResolvedNameRef(literal_name, ref) 1339 self.set_special(literal_name, value) 1340 1341 # Functions and invocations. 1342 1343 def set_invocation_usage(self): 1344 1345 """ 1346 Discard the current invocation storage figures, retaining the maximum 1347 values. 1348 """ 1349 1350 for path, (current, maximum) in self.function_targets.items(): 1351 self.importer.function_targets[path] = self.function_targets[path] = maximum 1352 1353 for path, (current, maximum) in self.function_arguments.items(): 1354 self.importer.function_arguments[path] = self.function_arguments[path] = maximum 1355 1356 def allocate_arguments(self, path, args): 1357 1358 """ 1359 Allocate temporary argument storage using current and maximum 1360 requirements for the given 'path' and 'args'. 1361 """ 1362 1363 init_item(self.function_targets, path, lambda: [0, 0]) 1364 t = self.function_targets[path] 1365 t[0] += 1 1366 t[1] = max(t[0], t[1]) 1367 1368 init_item(self.function_arguments, path, lambda: [0, 0]) 1369 t = self.function_arguments[path] 1370 t[0] += len(args) + 1 1371 t[1] = max(t[0], t[1]) 1372 1373 def deallocate_arguments(self, path, args): 1374 1375 "Deallocate temporary argument storage for the given 'path' and 'args'." 1376 1377 self.function_targets[path][0] -= 1 1378 self.function_arguments[path][0] -= len(args) + 1 1379 1380 # vim: tabstop=4 expandtab shiftwidth=4