1 #!/usr/bin/env python 2 3 """ 4 Translate the AST of a Python program into a more interpretable representation. 5 6 Copyright (C) 2007, 2008, 2009 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 micropython.opt import Optimiser 23 from micropython.common import * 24 from micropython.data import * 25 from micropython.rsvp import * 26 from micropython.trans import Helper 27 import compiler.ast 28 from compiler.visitor import ASTVisitor 29 30 # Program visitors. 31 32 class Translation(ASTVisitor, Helper): 33 34 "A translated module." 35 36 # Attribute access instructions, for use with the appropriate handlers. 37 38 attribute_load_instructions = ( 39 LoadAddress, LoadAddressContext, LoadAddressContextCond, 40 LoadAttr, LoadAttrIndex, LoadAttrIndexContext, LoadAttrIndexContextCond 41 ) 42 attribute_store_instructions = ( 43 None, None, None, 44 StoreAttr, StoreAttrIndex, None, None 45 ) 46 47 # Name access instructions, for use with the appropriate handlers. 48 49 name_load_instructions = (LoadName, LoadAddress) 50 name_store_instructions = (StoreName, StoreAddress) 51 52 def __init__(self, module, program): 53 54 """ 55 Initialise the translation with an inspected 'module' and the 'program' 56 container. 57 """ 58 59 ASTVisitor.__init__(self) 60 self.visitor = self 61 self.module = module 62 63 # Global program dependencies. 64 65 self.program = program 66 self.objtable = self.program.get_object_table() 67 self.paramtable = self.program.get_parameter_table() 68 self.importer = self.program.get_importer() 69 self.builtins = self.importer.modules.get("__builtins__") 70 71 # Optimisation. 72 73 self.optimiser = Optimiser(self, program.optimisations) 74 75 # The current unit being translated. 76 77 self.unit = None 78 79 # The temporary storage used by the current assignment expression. 80 81 self.expr_temp = [] 82 83 # Wiring within the code. 84 85 self.labels = {} 86 self.label_number = 0 87 self.loop_blocks = [] 88 self.exception_blocks = [] 89 90 self.reset() 91 92 def __repr__(self): 93 return "Translation(%r)" % self.module 94 95 def reset(self): 96 97 "Reset the state of the translator." 98 99 # The code itself. This is limited to the code for a particular block 100 # being processed. 101 102 self.blocks = [] 103 104 # Information about temporary values. 105 106 self.temp_positions = set() 107 self.max_temp_position = -1 108 109 # Information about instructions which construct frames. 110 111 self.frame_makers = [] 112 113 # Optimiser state must be reset for each unit. 114 115 self.optimiser.reset() 116 117 def get_module_code(self, final=0): 118 119 """ 120 Return the top-level module code including finalising code if 'final' is 121 set to a true value. 122 """ 123 124 self.unit = self.module 125 self.reset() 126 127 block = self.new_block() 128 self.set_block(block) 129 130 if self.module.module is not None: 131 self.dispatch(self.module.module) 132 133 # Finish off the translated program if appropriate. 134 135 if final: 136 self.new_op(Return()) 137 138 self.unit.temp_usage = self.max_temp_position + 1 139 self.unit.blocks = self.blocks 140 return self.blocks 141 142 def get_code(self, unit): 143 144 "Return the code for the given 'unit'." 145 146 self.unit = unit 147 self.reset() 148 149 block = self.new_block() 150 self.set_block(block) 151 152 if unit.astnode is not None: 153 self.dispatch(unit.astnode) 154 155 self.unit.temp_usage = self.max_temp_position + 2 # include space for instantiators to expand backwards 156 self.unit.blocks = self.blocks 157 return self.blocks 158 159 def get_instantiator_code(self, cls): 160 161 "Return the code for the given class 'cls'." 162 163 self.unit = cls.get_instantiator() 164 self.reset() 165 166 block = self.new_block() 167 self.set_block(block) 168 169 init_method = cls.get_init_method() 170 171 # Convert this frame back to being an invocation frame. 172 173 self.new_op(RecoverFrame()) 174 175 # Fix the current frame to include a new storage slot at the beginning. 176 177 self.new_op(AdjustFrame(-1)) 178 179 # Make an object. 180 181 self.make_object(cls, len(cls.instance_attributes())) 182 self.new_op(StoreFrame(0)) 183 184 # Invoke the appropriate initialiser. 185 186 self.new_op(LoadConst(init_method)) 187 self.new_op(LoadCallable()) 188 self.new_op(JumpWithFrame()) 189 190 # Store the object as the result. 191 192 self.new_op(LoadName(init_method.all_locals()["self"])) # load the context in the invocation frame 193 self.new_op(StoreResult()) 194 195 # Fix the current frame to release the storage slot at the beginning. 196 197 self.new_op(AdjustFrame(1)) 198 self.new_op(Return()) 199 200 self.unit.blocks = self.blocks 201 return self.blocks 202 203 # Visitor methods. 204 205 def default(self, node, *args): 206 raise TranslateError(self.module.full_name(), node, "Node class %r is not supported." % node.__class__) 207 208 def dispatch(self, node, *args): 209 return ASTVisitor.dispatch(self, node, *args) 210 211 # Concrete visitor methods. 212 213 # Binary operators. 214 215 visitAdd = Helper._visitBinary 216 visitBitand = Helper._visitBinary 217 visitBitor = Helper._visitBinary 218 visitBitxor = Helper._visitBinary 219 visitDiv = Helper._visitBinary 220 visitFloorDiv = Helper._visitBinary 221 visitLeftShift = Helper._visitBinary 222 visitMod = Helper._visitBinary 223 visitMul = Helper._visitBinary 224 visitPower = Helper._visitBinary 225 visitRightShift = Helper._visitBinary 226 visitSub = Helper._visitBinary 227 228 # Unary operators. 229 230 visitInvert = Helper._visitUnary 231 visitUnaryAdd = Helper._visitUnary 232 visitUnarySub = Helper._visitUnary 233 234 # Logical operators. 235 236 def visitAnd(self, node): 237 end_block = self.new_block() 238 temp_pos = self.reserve_temp() 239 temp = LoadTemp(temp_pos) 240 241 for n in node.nodes[:-1]: 242 self.dispatch(n) 243 self.new_op(StoreTemp(temp_pos)) 244 245 self._generateTestBoolean(n, temp) 246 self.new_op(JumpIfFalse(end_block)) 247 248 self.dispatch(node.nodes[-1]) 249 self.new_op(StoreTemp(temp_pos)) 250 251 self.set_block(end_block) 252 253 self.new_op(temp) 254 self.discard_temp(temp) 255 256 def visitNot(self, node): 257 self.dispatch(node.expr) 258 259 temp = self.optimiser.optimise_temp_storage() 260 self._generateTestBoolean(node.expr, temp) 261 self.discard_temp(temp) 262 263 self.new_op(InvertBoolean()) 264 self._generateLoadBoolean(node) 265 266 def visitOr(self, node): 267 end_block = self.new_block() 268 temp_pos = self.reserve_temp() 269 temp = LoadTemp(temp_pos) 270 271 for n in node.nodes[:-1]: 272 self.dispatch(n) 273 self.new_op(StoreTemp(temp_pos)) 274 275 self._generateTestBoolean(n, temp) 276 self.new_op(JumpIfTrue(end_block)) 277 278 self.dispatch(node.nodes[-1]) 279 self.new_op(StoreTemp(temp_pos)) 280 281 self.set_block(end_block) 282 283 self.new_op(temp) 284 self.discard_temp(temp) 285 286 # Comparisons. 287 288 def visitCompare(self, node): 289 290 """ 291 _t1 = node.expr 292 _t1 op1 _t2 and _t2 op2 _t3 and ... 293 """ 294 295 end_block = self.new_block() 296 297 self.dispatch(node.expr) 298 temp2 = self.optimiser.optimise_temp_storage() 299 300 # NOTE: Replicated by some code in micropython.inspect.visitCompare. 301 302 last_op = node.ops[-1] 303 304 for op in node.ops: 305 op_name, next_node = op 306 methods = comparison_methods[op_name] 307 308 # Propagate the arguments as we traverse the construct. 309 310 temp1 = temp2 311 self.dispatch(next_node) 312 temp2 = self.optimiser.optimise_temp_storage() 313 314 # Use the appropriate mechanism, setting the boolean status for the 315 # comparison. 316 317 if methods is not None: 318 left_method, right_method = methods 319 320 # Generate method call using evaluated argument and next node. 321 322 temp_result = self._generateBinary(node, temp1, temp2, left_method, right_method) 323 self.new_op(temp_result) 324 self._generateTestBoolean(node, temp_result) 325 self.discard_temp(temp_result) 326 327 else: 328 # Deal with the special operators. 329 330 if op_name.startswith("is"): 331 self.new_op(temp1) 332 self.record_value() 333 self.new_op(temp2) 334 self.new_op(TestIdentity()) 335 self.set_source() 336 self.discard_value() 337 338 elif op_name.endswith("in"): 339 self.new_op(temp2) 340 341 # Get method on temp2. 342 343 self._generateAttr(node, "__contains__", self.attribute_load_instructions) 344 temp_method = self.optimiser.optimise_temp_storage() 345 346 # Add arguments. 347 # NOTE: No support for defaults. 348 349 self._startCallFunc() 350 self.new_op(temp2) 351 self.new_op(StoreFrame(0)) 352 self.new_op(temp1) 353 self.new_op(StoreFrame(1)) 354 self._endCallFuncArgs(2) 355 self._doCallFunc(temp_method) 356 self._endCallFunc(temp_method) 357 358 temp_result = self.get_temp() 359 self._generateTestBoolean(node, temp_result) 360 self.discard_temp(temp_result) 361 362 if op_name.find("not") != -1: 363 self.new_op(InvertBoolean()) 364 365 # Test the result and jump to the end block if false. 366 367 if op is not last_op: 368 self.new_op(JumpIfFalse(end_block)) 369 370 # Compilation duties... 371 372 self.discard_temp(temp1) 373 374 self.discard_temp(temp2) 375 376 # With the status set above, produce a boolean result. 377 378 self.set_block(end_block) 379 380 # Yield the appropriate value. 381 382 self._generateLoadBoolean(node) 383 384 # Expressions. 385 386 def visitBackquote(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Backquote") 387 388 def visitCallFunc(self, node): 389 390 """ 391 Evaluate positional arguments, evaluate and store keyword arguments in 392 the correct location, then invoke the function. 393 """ 394 395 # Mark the frame, evaluate the target, generate the call. 396 397 self._startCallFunc() 398 self.dispatch(node.node) 399 temp, target = self._generateCallFunc(node.args, node) 400 self._doCallFunc(temp, target) 401 self._endCallFunc(temp, target) 402 403 def visitConst(self, node): 404 const = self.importer.get_constant(node.value) 405 self.new_op(LoadConst(const)) 406 407 def visitDict(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Dict") 408 409 def visitEllipsis(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Ellipsis") 410 411 def visitExec(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Exec") 412 413 def visitExpression(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Expression") 414 415 def visitGenExpr(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "GenExpr") 416 417 def visitGenExprFor(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "GenExprFor") 418 419 def visitGenExprIf(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "GenExprIf") 420 421 def visitGenExprInner(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "GenExprInner") 422 423 def visitGetattr(self, node): 424 self._visitAttr(node, self.attribute_load_instructions) 425 426 def visitList(self, node): 427 self._generateSequence("list", node) 428 429 def visitListComp(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "ListComp") 430 431 def visitListCompFor(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "ListCompFor") 432 433 def visitListCompIf(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "ListCompIf") 434 435 def visitName(self, node): 436 if self.importer.predefined_constants.has_key(node.name): 437 const = self.importer.get_predefined_constant(node.name) 438 self.new_op(LoadConst(const)) 439 else: 440 self._visitName(node, self.name_load_instructions) 441 442 def visitSlice(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Slice") 443 444 def visitSubscript(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Subscript") 445 446 def visitTuple(self, node): 447 self._generateSequence("tuple", node) 448 449 # Definitions. 450 451 def visitAssign(self, node): 452 453 """ 454 Evaluate the expression from the given 'node' and assign it to the 455 associated recipients. 456 """ 457 458 self.dispatch(node.expr) 459 460 # Record the value and then dispatch to the assignment targets. 461 462 self.record_value(self.has_immediate_usage(node.nodes)) 463 464 for n in node.nodes: 465 self.dispatch(n) 466 467 self.discard_value() 468 469 def visitAssAttr(self, node): 470 471 "Assign the assignment expression to the recipient 'node'." 472 473 self._visitAttr(node, self.attribute_store_instructions) 474 self.set_source() 475 476 def visitAssList(self, node): 477 478 """ 479 Assign items from the assignment expression to each of the recipients 480 found within the given 'node'. 481 """ 482 483 for i, n in enumerate(node.nodes): 484 self._startCallFunc() 485 self.new_op(self.expr_temp[-1]) 486 self._generateAttr(node, "__getitem__", self.attribute_load_instructions) 487 temp, target = self._generateCallFunc([compiler.ast.Const(i)], node) 488 self._doCallFunc(temp, target) 489 self._endCallFunc(temp, target) 490 491 # Provide a different source value. 492 # NOTE: Permitting immediate usage given that neither name nor 493 # NOTE: attribute accesses should involve a function call 494 # NOTE: overwriting the above result. 495 496 self.record_value(self.is_immediate_user(n)) 497 self.dispatch(n) 498 self.discard_value() 499 500 def visitAssName(self, node): 501 502 "Assign the assignment expression to the recipient 'node'." 503 504 self._visitName(node, self.name_store_instructions) 505 self.set_source() 506 507 visitAssTuple = visitAssList 508 509 def visitAugAssign(self, node): 510 use_binary_block = self.new_block() 511 end_block = self.new_block() 512 513 # Evaluate the expression. 514 515 self.dispatch(node.expr) 516 temp2 = self.optimiser.optimise_temp_storage() 517 518 # Evaluate the target. 519 520 self.dispatch(node.node) 521 temp1 = self.optimiser.optimise_temp_storage() 522 523 # Find the augmented assignment method and attempt to use it. 524 525 aug_method, (left_method, right_method) = augassign_methods[node.op] 526 temp_out = self._generateOpMethod(node, temp1, temp2, aug_method, use_binary_block, end_block) 527 self.discard_temp(temp_out) # NOTE: Will re-use the same storage. 528 529 # Where no such method exists, use the binary operator methods. 530 531 self.set_block(use_binary_block) 532 temp_out = self._generateBinary(node, temp1, temp2, left_method, right_method) 533 534 # Assign the result to the name. 535 536 self.set_block(end_block) 537 self.new_op(temp_out) 538 self.record_value(1) 539 540 if isinstance(node.node, compiler.ast.Name): 541 self.visitAssName(node.node) 542 elif isinstance(node.node, compiler.ast.Getattr): 543 self.visitAssAttr(node.node) 544 else: 545 raise TranslationNotImplementedError(self.module.full_name(), node, "AugAssign(Slice or Subscript)") 546 547 self.discard_value() 548 549 # Compilation duties... 550 551 self.discard_temp(temp1) 552 self.discard_temp(temp2) 553 554 def visitClass(self, node): 555 if not node.unit.referenced: 556 return 557 558 # Store the name. 559 560 self.new_op(LoadConst(node.unit)) 561 self.record_value() 562 self._visitName(node, self.name_store_instructions) 563 self.set_source() 564 self.discard_value() 565 566 # Visit the code. 567 568 unit = self.unit 569 self.unit = node.unit 570 self.dispatch(node.code) 571 self.unit = unit 572 573 def visitDecorators(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Decorators") 574 575 def visitFrom(self, node): pass 576 577 def visitFunction(self, node): 578 if not node.unit.referenced and (not node.unit.is_method() or not node.unit.parent.has_key(node.unit.name)): 579 return 580 581 # Only store the name when visiting this node from outside. 582 583 if self.unit is not node.unit: 584 self.new_op(LoadConst(node.unit)) 585 586 self.record_value() 587 self._visitName(node, self.name_store_instructions) # AssName equivalent 588 self.set_source() 589 self.discard_value() 590 591 self._generateFunctionDefaults(node.unit) 592 593 # Visiting of the code occurs when get_code is invoked on this node. 594 595 else: 596 extend = ExtendFrame() 597 self.new_op(extend) 598 599 self.dispatch(node.code) 600 if not isinstance(self.last_op(), Return): 601 self.dispatch(compiler.ast.Name("None")) 602 self.new_op(StoreResult()) 603 604 self.new_op(Return()) 605 606 self.set_frame_usage(node, extend) 607 608 def visitGlobal(self, node): pass 609 610 def visitImport(self, node): pass 611 612 def visitKeyword(self, node): pass 613 614 def visitLambda(self, node): 615 616 """ 617 Lambda functions can be represented as globally defined functions 618 provided they do not define any default parameter values, since these 619 may defined in a non-global scope. 620 621 Where defaults are defined, an object must be created and its content 622 defined: the callable member of the object's structure must be set to 623 the lambda function definition; each default must be attached to the 624 object as an attribute, as is the case with normal functions and 625 methods. 626 """ 627 628 # Produce the reference to this function when visiting this node from 629 # outside. 630 631 if self.unit is not node.unit: 632 temp = self._generateFunctionDefaults(node.unit) 633 self.new_op(LoadConst(node.unit)) 634 635 # Populate the new object required for the function. 636 637 if temp is not None: 638 self.new_op(LoadCallable()) 639 self.new_op(temp) 640 self.new_op(StoreCallable()) 641 642 self.new_op(temp) 643 #self.discard_temp(temp) 644 645 # Visiting of the code occurs when get_code is invoked on this node. 646 647 else: 648 self.dispatch(node.code) 649 self.new_op(StoreResult()) 650 self.new_op(Return()) 651 652 def visitModule(self, node): 653 extend = ExtendFrame() 654 self.new_op(extend) 655 self.dispatch(node.node) 656 self.set_frame_usage(node, extend) 657 658 # Statements. 659 660 def visitStmt(self, node): 661 662 "Process the collection of statements provided by 'node'." 663 664 for n in node.nodes: 665 666 # Process the statement. 667 668 self.dispatch(n) 669 670 # Discard temporary storage. 671 672 if self.temp_positions: 673 #print "Had temp", self.temp_positions 674 self.temp_positions = set() 675 676 # Prevent incorrect optimisation by resetting the optimiser after 677 # each statement. 678 679 self.optimiser.reset() 680 681 def visitAssert(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Assert") 682 683 def visitBreak(self, node): 684 next_block, exit_block = self.get_loop_blocks() 685 self.new_op(Jump(exit_block)) 686 687 def visitContinue(self, node): 688 next_block, exit_block = self.get_loop_blocks() 689 self.new_op(Jump(next_block)) 690 691 def visitDiscard(self, node): 692 self.dispatch(node.expr) 693 self.optimiser.optimise_unused_results() 694 695 def visitFor(self, node): 696 next_handler_block = self.new_block() 697 end_handler_block = self.new_block() 698 exit_block = self.new_block() 699 next_block = self.new_block() 700 else_block = self.new_block() 701 702 # Get the "list" to be iterated over, obtain its iterator. 703 704 self._startCallFunc() 705 self.dispatch(node.list) 706 self._generateAttr(node, "__iter__", self.attribute_load_instructions) 707 temp, target = self._generateCallFunc([], node) 708 self._doCallFunc(temp, target) 709 self._endCallFunc(temp, target) 710 711 temp_iterator = self.optimiser.optimise_temp_storage() 712 713 # In the loop... 714 715 self.set_block(next_block) 716 717 # Handle exceptions when calling "next"... 718 719 self.new_op(PushHandler(next_handler_block)) 720 721 # Use the iterator to get the next value. 722 723 self._startCallFunc() 724 self.new_op(temp_iterator) 725 self._generateAttr(node, "next", self.attribute_load_instructions) 726 temp, target = self._generateCallFunc([], node) 727 self._doCallFunc(temp, target) 728 self._endCallFunc(temp, target) 729 730 # Record the value to be assigned. 731 732 self.record_value() 733 734 # Skip the handler where the call was successful. 735 736 self.new_op(Jump(end_handler_block)) 737 738 # Enter the exception handler. 739 740 self.set_block(next_handler_block) 741 self.new_op(PopHandler()) 742 743 # Test for StopIteration. 744 745 self.load_builtin("StopIteration", node) 746 self.new_op(CheckException()) 747 if node.else_ is not None: 748 self.new_op(JumpIfTrue(else_block)) 749 else: 750 self.new_op(JumpIfTrue(exit_block)) 751 752 # Re-raise the exception otherwise. 753 754 self.new_op(RaiseException()) 755 756 # After the handler. 757 758 self.set_block(end_handler_block) 759 760 # Assign to the target. 761 762 self.dispatch(node.assign) 763 self.discard_value() 764 765 # Process the body with the current next and exit points. 766 767 self.add_loop_blocks(next_block, exit_block) 768 self.dispatch(node.body) 769 self.drop_loop_blocks() 770 771 # Repeat the loop. 772 773 self.new_op(Jump(next_block)) 774 775 # Produce the "else" section. 776 777 if node.else_ is not None: 778 self.set_block(exit_block) 779 780 self.dispatch(node.else_) 781 782 # After the loop... 783 784 self.set_block(exit_block) 785 786 # Compilation duties... 787 788 self.discard_temp(temp_iterator) 789 790 def visitIf(self, node): 791 first = 1 792 exit_block = self.new_block() 793 794 clauses = node.tests + [(None, node.else_)] 795 last_clause = clauses[-1] 796 797 for clause in clauses: 798 test, body = clause 799 if body is None: 800 break 801 if not first: 802 self.set_block(next_block) 803 if test is not None: 804 self.dispatch(test) 805 next_block = self.new_block() 806 self.new_op(JumpIfFalse(next_block)) 807 self.dispatch(body) 808 if clause is not last_clause: 809 self.new_op(Jump(exit_block)) 810 811 first = 0 812 813 self.set_block(exit_block) 814 815 def visitPass(self, node): pass 816 817 def visitPrint(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Print") 818 819 def visitPrintnl(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Printnl") 820 821 def visitRaise(self, node): 822 # NOTE: expr1 only => instance provided 823 self.dispatch(node.expr1) 824 825 if node.expr2 is not None: 826 temp = self.optimiser.optimise_temp_storage() 827 828 self.dispatch(node.expr2) 829 temp_arg = self.optimiser.optimise_temp_storage() 830 831 self._startCallFunc() 832 self.new_op(temp_arg) 833 self.new_op(StoreFrame(0)) 834 self._endCallFuncArgs(1) 835 self._doCallFunc(temp) 836 self._endCallFunc(temp) 837 838 self.discard_temp(temp_arg) 839 840 self.new_op(StoreException()) 841 self.new_op(RaiseException()) 842 843 def visitReturn(self, node): 844 if node.value is not None: 845 self.dispatch(node.value) 846 else: 847 self.dispatch(compiler.ast.Name("None")) 848 849 self.new_op(StoreResult()) 850 self.new_op(Return()) 851 852 def visitTryExcept(self, node): 853 exit_block = self.new_block() 854 else_block = self.new_block() 855 handler_block = self.new_block() 856 857 self.add_exception_blocks(handler_block, exit_block) 858 859 # Try... 860 # Produce the code, then jump to the exit. 861 862 self.new_op(PushHandler(handler_block)) 863 self.dispatch(node.body) 864 self.new_op(PopHandler()) 865 866 if node.else_ is not None: 867 self.new_op(Jump(else_block)) 868 else: 869 self.new_op(Jump(exit_block)) 870 871 # Start of handlers. 872 873 self.set_block(handler_block) 874 875 self.new_op(PopHandler()) 876 877 for name, assignment, handler in node.handlers: 878 next_block = self.new_block() 879 880 # Test the given exception against the current exception. 881 882 if name is not None: 883 self.dispatch(name) 884 885 self.new_op(CheckException()) 886 self.new_op(JumpIfFalse(next_block)) 887 888 # Handle assignment to exception variable. 889 890 if assignment is not None: 891 self.new_op(LoadException()) 892 893 # Record the value to be assigned. 894 895 self.record_value() 896 self.dispatch(assignment) 897 self.discard_value() 898 899 # Produce the handler code, then jump to the exit. 900 901 self.dispatch(handler) 902 self.new_op(Jump(exit_block)) 903 904 self.set_block(next_block) 905 906 # Unhandled exceptions. 907 908 self.new_op(RaiseException()) 909 910 # Optional else clause. 911 912 if node.else_ is not None: 913 self.set_block(else_block) 914 915 self.dispatch(node.else_) 916 917 self.set_block(exit_block) 918 self.drop_exception_blocks() 919 920 def visitTryFinally(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "TryFinally") 921 922 def visitWhile(self, node): 923 exit_block = self.new_block() 924 next_block = self.new_block() 925 else_block = self.new_block() 926 927 self.set_block(next_block) 928 self.dispatch(node.test) 929 if node.else_ is not None: 930 self.new_op(JumpIfFalse(else_block)) 931 else: 932 self.new_op(JumpIfFalse(exit_block)) 933 934 self.add_loop_blocks(next_block, exit_block) 935 936 self.dispatch(node.body) 937 self.new_op(Jump(next_block)) 938 939 if node.else_ is not None: 940 self.set_block(else_block) 941 942 self.dispatch(node.else_) 943 944 self.set_block(exit_block) 945 946 self.drop_loop_blocks() 947 948 def visitWith(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "With") 949 950 def visitYield(self, node): raise TranslationNotImplementedError(self.module.full_name(), node, "Yield") 951 952 # 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