| 1 | """
|
| 2 | pass_state.py
|
| 3 | """
|
| 4 | from __future__ import print_function
|
| 5 |
|
| 6 | import os
|
| 7 | import re
|
| 8 | import subprocess
|
| 9 | from collections import defaultdict
|
| 10 |
|
| 11 | from mypy.types import Type
|
| 12 | from mypy.nodes import Expression
|
| 13 |
|
| 14 | from mycpp.util import join_name, log, split_py_name, SymbolPath
|
| 15 |
|
| 16 | from typing import Optional
|
| 17 |
|
| 18 | _ = log
|
| 19 |
|
| 20 |
|
| 21 | class ModuleMember(object):
|
| 22 | """
|
| 23 | A member of a Python module.
|
| 24 |
|
| 25 | e.g. core.state.Mem => core::state::Mem
|
| 26 | """
|
| 27 |
|
| 28 | def __init__(self, module_path: SymbolPath, member: str) -> None:
|
| 29 | self.module_path = module_path
|
| 30 | self.member = member
|
| 31 |
|
| 32 |
|
| 33 | class StaticObjectMember(object):
|
| 34 | """
|
| 35 | A static member of an object. Usually a a method like an alternative constructor.
|
| 36 |
|
| 37 | e.g. runtime_asdl.Cell.CreateNull() => runtime_asdl::Cell::CreateNull()
|
| 38 | """
|
| 39 |
|
| 40 | def __init__(self, base_type_name: SymbolPath, member: str) -> None:
|
| 41 | self.base_type_name = base_type_name
|
| 42 | self.member = member
|
| 43 |
|
| 44 |
|
| 45 | class HeapObjectMember(object):
|
| 46 | """
|
| 47 | A member of a heap-allocated object.
|
| 48 |
|
| 49 | e.g foo.empty() => foo->empty()
|
| 50 | """
|
| 51 |
|
| 52 | def __init__(self, object_expr: Expression, object_type: Type,
|
| 53 | member: str) -> None:
|
| 54 | self.object_expr = object_expr
|
| 55 | self.object_type = object_type
|
| 56 | self.member = member
|
| 57 |
|
| 58 |
|
| 59 | class StackObjectMember(object):
|
| 60 | """
|
| 61 | A member of a stack-allocated object.
|
| 62 |
|
| 63 | e.g foo.empty() => foo.empty()
|
| 64 | """
|
| 65 |
|
| 66 | def __init__(self, object_expr: Expression, object_type: Type,
|
| 67 | member: str) -> None:
|
| 68 | self.ojbect_expr = object_expr
|
| 69 | self.object_type = object_type
|
| 70 | self.member = member
|
| 71 |
|
| 72 |
|
| 73 | class Virtual(object):
|
| 74 | """Calculate which C++ methods need the virtual keyword.
|
| 75 |
|
| 76 | See unit test for example usage.
|
| 77 | """
|
| 78 |
|
| 79 | def __init__(self) -> None:
|
| 80 | self.methods: dict[SymbolPath, list[str]] = defaultdict(list)
|
| 81 | self.subclasses: dict[SymbolPath, list[tuple[str]]] = defaultdict(list)
|
| 82 | self.virtuals: dict[tuple[SymbolPath, str], Optional[tuple[SymbolPath,
|
| 83 | str]]] = {}
|
| 84 | self.has_vtable: dict[SymbolPath, bool] = {}
|
| 85 | self.can_reorder_fields: dict[SymbolPath, bool] = {}
|
| 86 |
|
| 87 | # _Executor -> vm::_Executor
|
| 88 | self.base_class_unique: dict[str, SymbolPath] = {}
|
| 89 |
|
| 90 | # These are called on the Forward Declare pass
|
| 91 | def OnMethod(self, class_name: SymbolPath, method_name: str) -> None:
|
| 92 | #log('OnMethod %s %s', class_name, method_name)
|
| 93 |
|
| 94 | # __init__ and so forth don't count
|
| 95 | if method_name.startswith('__') and method_name.endswith('__'):
|
| 96 | return
|
| 97 |
|
| 98 | self.methods[class_name].append(method_name)
|
| 99 |
|
| 100 | def OnSubclass(self, base_class: SymbolPath, subclass: SymbolPath) -> None:
|
| 101 | if len(base_class) > 1:
|
| 102 | # Hack for
|
| 103 | #
|
| 104 | # class _Executor: pass
|
| 105 | # versus
|
| 106 | # class MyExecutor(vm._Executor): pass
|
| 107 | base_key = base_class[-1]
|
| 108 |
|
| 109 | # Fail if we have two base classes in different namespaces with the same
|
| 110 | # name.
|
| 111 | if base_key in self.base_class_unique:
|
| 112 | # Make sure we don't have collisions
|
| 113 | assert (self.base_class_unique[base_key] == base_class or
|
| 114 | base_class
|
| 115 | in self.subclasses[self.base_class_unique[base_key]]
|
| 116 | ), base_class
|
| 117 | else:
|
| 118 | self.base_class_unique[base_key] = base_class
|
| 119 |
|
| 120 | else:
|
| 121 | base_key = base_class
|
| 122 |
|
| 123 | self.subclasses[base_class].append(subclass)
|
| 124 |
|
| 125 | def Calculate(self) -> None:
|
| 126 | """Call this after the forward declare pass."""
|
| 127 | for base_class, subclasses in self.subclasses.items():
|
| 128 | self.can_reorder_fields[base_class] = False
|
| 129 |
|
| 130 | for subclass in subclasses:
|
| 131 | self.can_reorder_fields[subclass] = False
|
| 132 |
|
| 133 | b_methods = self.methods[base_class]
|
| 134 | s_methods = self.methods[subclass]
|
| 135 | overlapping = set(b_methods) & set(s_methods)
|
| 136 | for method in overlapping:
|
| 137 | self.virtuals[(base_class, method)] = None
|
| 138 | self.virtuals[(subclass, method)] = (base_class, method)
|
| 139 | if overlapping:
|
| 140 | self.has_vtable[base_class] = True
|
| 141 | self.has_vtable[subclass] = True
|
| 142 |
|
| 143 | # These is called on the Decl pass
|
| 144 | def IsVirtual(self, class_name: SymbolPath, method_name: str) -> bool:
|
| 145 | return (class_name, method_name) in self.virtuals
|
| 146 |
|
| 147 | def HasVTable(self, class_name: SymbolPath) -> bool:
|
| 148 | return class_name in self.has_vtable
|
| 149 |
|
| 150 | def CanReorderFields(self, class_name: SymbolPath) -> bool:
|
| 151 | if class_name in self.can_reorder_fields:
|
| 152 | return self.can_reorder_fields[class_name]
|
| 153 | else:
|
| 154 | return True # by default they can be reordered
|
| 155 |
|
| 156 |
|
| 157 | def SymbolPathToReference(func: str, p: SymbolPath) -> str:
|
| 158 | if len(p) > 1:
|
| 159 | return '$ObjectMember({}, {})'.format(join_name(p[:-1], delim='.'), p[-1])
|
| 160 |
|
| 161 | return '$LocalVariable({}, {})'.format(func, p[0])
|
| 162 |
|
| 163 |
|
| 164 | class Fact(object):
|
| 165 | """
|
| 166 | An abstract fact. These can be used to build up datalog programs.
|
| 167 | """
|
| 168 |
|
| 169 | def __init__(self) -> None:
|
| 170 | pass
|
| 171 |
|
| 172 | def name(self) -> str:
|
| 173 | raise NotImplementedError()
|
| 174 |
|
| 175 | def Generate(self, func: str, statement: int) -> str:
|
| 176 | raise NotImplementedError()
|
| 177 |
|
| 178 |
|
| 179 | class FunctionCall(Fact):
|
| 180 |
|
| 181 | def __init__(self, callee: str) -> None:
|
| 182 | self.callee = callee
|
| 183 |
|
| 184 | def name(self) -> str:
|
| 185 | return 'call'
|
| 186 |
|
| 187 | def Generate(self, func: str, statement: int) -> str:
|
| 188 | return '{}\t{}\t{}\n'.format(func, statement, self.callee)
|
| 189 |
|
| 190 |
|
| 191 | class Definition(Fact):
|
| 192 | """
|
| 193 | The definition of a variable. This corresponds to an allocation.
|
| 194 | """
|
| 195 |
|
| 196 | def __init__(self, ref: SymbolPath, obj: str) -> None:
|
| 197 | self.ref = ref
|
| 198 | self.obj = obj
|
| 199 |
|
| 200 | def name(self) -> str:
|
| 201 | return 'assign'
|
| 202 |
|
| 203 | def Generate(self, func: str, statement: int) -> str:
|
| 204 | return '{}\t{}\t{}\t{}\n'.format(func, statement,
|
| 205 | SymbolPathToReference(func, self.ref),
|
| 206 | self.obj)
|
| 207 |
|
| 208 |
|
| 209 | class Assignment(Fact):
|
| 210 | """
|
| 211 | The assignment of one variable or object member to another.
|
| 212 | """
|
| 213 |
|
| 214 | def __init__(self, lhs: SymbolPath, rhs: SymbolPath) -> None:
|
| 215 | self.lhs = lhs
|
| 216 | self.rhs = rhs
|
| 217 |
|
| 218 | def name(self) -> str:
|
| 219 | return 'assign'
|
| 220 |
|
| 221 | def Generate(self, func: str, statement: int) -> str:
|
| 222 | return '{}\t{}\t{}\t$Ref({})\n'.format(func, statement,
|
| 223 | SymbolPathToReference(func, self.lhs),
|
| 224 | SymbolPathToReference(func, self.rhs))
|
| 225 |
|
| 226 |
|
| 227 | class Use(Fact):
|
| 228 | """
|
| 229 | The use of a reference.
|
| 230 | """
|
| 231 |
|
| 232 | def __init__(self, ref: SymbolPath) -> None:
|
| 233 | self.ref = ref
|
| 234 |
|
| 235 | def name(self) -> str:
|
| 236 | return 'use'
|
| 237 |
|
| 238 | def Generate(self, func: str, statement: int) -> str:
|
| 239 | return '{}\t{}\t{}\n'.format(func, statement,
|
| 240 | SymbolPathToReference(func, self.ref))
|
| 241 |
|
| 242 |
|
| 243 | class ControlFlowGraph(object):
|
| 244 | """
|
| 245 | A simple control-flow graph.
|
| 246 |
|
| 247 | Every statement in the program is represented as a node in a graph with
|
| 248 | unique a numeric ID. Control flow is represented as directed edges through
|
| 249 | the graph. Loops can introduce back-edges. Every node in the graph will
|
| 250 | satisfy at least one of the following conditions:
|
| 251 |
|
| 252 | - Its indegree is at least one.
|
| 253 |
|
| 254 | - Its outdegree is at least one.
|
| 255 |
|
| 256 | For simple linear graphs all you need is the AddStatement method. For more
|
| 257 | complex flows there is a set of context managers below to help simplify
|
| 258 | construction.
|
| 259 |
|
| 260 | - For branches-like statements (e.g. if- and try- statements) use
|
| 261 | CfgBranchContext. It will take care of the details associated with
|
| 262 | stitching the different branches to statements in the next statement.
|
| 263 |
|
| 264 | - For loops, use CfgLoopContext. It will take care of adding back-edges
|
| 265 | and connecting break statements to any statements that proceed the
|
| 266 | loop.
|
| 267 |
|
| 268 | - CfgBlockContext can be used for simple cases where you just want to
|
| 269 | track the beginning and end of a sequence of statements.
|
| 270 |
|
| 271 | Statements can carry annotations called facts, which are used as inputs to
|
| 272 | datalog programs to perform dataflow diffrent kinds of dataflow analyses.
|
| 273 | To annotate a statement, use the AddFact method with any object that
|
| 274 | implements the Fact interface.
|
| 275 |
|
| 276 | See the unit tests in pass_state_test.py and the mycpp phase in
|
| 277 | control_flow_pass.py for detailed examples of usage.
|
| 278 | """
|
| 279 |
|
| 280 | def __init__(self) -> None:
|
| 281 | self.statement_counter: int = 0
|
| 282 | self.edges: set[tuple[int, int]] = set({})
|
| 283 | self.block_stack: list[int] = []
|
| 284 | self.predecessors: set[int] = set({})
|
| 285 | self.deadends: set[int] = set({})
|
| 286 |
|
| 287 | # order doesn't actually matter here, but sets require elements to be
|
| 288 | # hashable
|
| 289 | self.facts: dict[int, list[Fact]] = defaultdict(list)
|
| 290 |
|
| 291 | def AddEdge(self, pred: int, succ: int) -> None:
|
| 292 | """
|
| 293 | Add a directed edge from pred to succ. If pred is a deadend, its
|
| 294 | non-deadends will be used instead.
|
| 295 | """
|
| 296 | if pred in self.deadends:
|
| 297 | for w in [u for (u, v) in self.edges if v == pred]:
|
| 298 | self.AddEdge(w, succ)
|
| 299 | else:
|
| 300 | self.edges.add((pred, succ))
|
| 301 |
|
| 302 | def AddDeadend(self, statement: int):
|
| 303 | """
|
| 304 | Mark a statement as a dead-end (e.g. return or continue).
|
| 305 | """
|
| 306 | self.deadends.add(statement)
|
| 307 |
|
| 308 | def AddStatement(self) -> int:
|
| 309 | """
|
| 310 | Add a new statement and return its ID.
|
| 311 | """
|
| 312 | if len(self.predecessors) == 0:
|
| 313 | if len(self.block_stack):
|
| 314 | self.predecessors.add(self.block_stack[-1])
|
| 315 | else:
|
| 316 | self.predecessors.add(self.statement_counter)
|
| 317 |
|
| 318 | self.statement_counter += 1
|
| 319 | for pred in self.predecessors:
|
| 320 | self.AddEdge(pred, self.statement_counter)
|
| 321 |
|
| 322 | self.predecessors = set({})
|
| 323 |
|
| 324 | if len(self.block_stack):
|
| 325 | self.block_stack[-1] = self.statement_counter
|
| 326 |
|
| 327 | return self.statement_counter
|
| 328 |
|
| 329 | def AddFact(self, statement: int, fact: Fact) -> None:
|
| 330 | """
|
| 331 | Annotate a statement with a fact.
|
| 332 | """
|
| 333 | self.facts[statement].append(fact)
|
| 334 |
|
| 335 | def _PushBlock(self, begin: Optional[int] = None) -> int:
|
| 336 | """
|
| 337 | Start a block at the given statement ID. If a beginning statement isn't
|
| 338 | provided one will be created and its ID will be returend.
|
| 339 |
|
| 340 | Direct use of this function is discouraged. Consider using one of the
|
| 341 | block context managers below instead.
|
| 342 | """
|
| 343 | if begin is None:
|
| 344 | begin = self.AddStatement()
|
| 345 | else:
|
| 346 | self.predecessors.add(begin)
|
| 347 |
|
| 348 | self.block_stack.append(begin)
|
| 349 | return begin
|
| 350 |
|
| 351 | def _PopBlock(self) -> int:
|
| 352 | """
|
| 353 | Pop a block from the top of the stack and return the ID of the block's
|
| 354 | last statement.
|
| 355 |
|
| 356 | Direct use of this function is discouraged. Consider using one of the
|
| 357 | block context managers below instead.
|
| 358 | """
|
| 359 | assert len(self.block_stack)
|
| 360 | last = self.block_stack.pop()
|
| 361 | if len(self.block_stack) and last not in self.deadends:
|
| 362 | self.block_stack[-1] = last
|
| 363 |
|
| 364 | return last
|
| 365 |
|
| 366 |
|
| 367 | class CfgBlockContext(object):
|
| 368 | """
|
| 369 | Context manager to make dealing with things like with-statements easier.
|
| 370 | """
|
| 371 |
|
| 372 | def __init__(self,
|
| 373 | cfg: ControlFlowGraph,
|
| 374 | begin: Optional[int] = None) -> None:
|
| 375 | self.cfg = cfg
|
| 376 | if cfg is None:
|
| 377 | return
|
| 378 |
|
| 379 | self.entry = self.cfg._PushBlock(begin)
|
| 380 | self.exit = self.entry
|
| 381 |
|
| 382 | def __enter__(self) -> None:
|
| 383 | return self if self.cfg else None
|
| 384 |
|
| 385 | def __exit__(self, *args) -> None:
|
| 386 | if not self.cfg:
|
| 387 | return
|
| 388 |
|
| 389 | self.exit = self.cfg._PopBlock()
|
| 390 |
|
| 391 |
|
| 392 | class CfgBranchContext(object):
|
| 393 | """
|
| 394 | Context manager to make dealing with if-else blocks easier.
|
| 395 | """
|
| 396 |
|
| 397 | def __init__(self, cfg: ControlFlowGraph, branch_point: int) -> None:
|
| 398 | self.cfg = cfg
|
| 399 | self.entry = branch_point
|
| 400 | self.exit = self.entry
|
| 401 | if cfg is None:
|
| 402 | return
|
| 403 |
|
| 404 | self.arms = []
|
| 405 | self.pushed = False
|
| 406 |
|
| 407 | def AddBranch(self, entry: Optional[int] = None):
|
| 408 | if not self.cfg:
|
| 409 | return CfgBranchContext(None, None)
|
| 410 |
|
| 411 | self.arms.append(CfgBranchContext(self.cfg, entry or self.entry))
|
| 412 | self.cfg._PushBlock(self.arms[-1].entry)
|
| 413 | self.arms[-1].pushed = True
|
| 414 | return self.arms[-1]
|
| 415 |
|
| 416 | def __enter__(self) -> None:
|
| 417 | return self
|
| 418 |
|
| 419 | def __exit__(self, *args) -> None:
|
| 420 | if not self.cfg:
|
| 421 | return
|
| 422 |
|
| 423 | if self.pushed:
|
| 424 | self.exit = self.cfg._PopBlock()
|
| 425 |
|
| 426 | for arm in self.arms:
|
| 427 | if arm.exit not in self.cfg.deadends:
|
| 428 | self.cfg.predecessors.add(arm.exit)
|
| 429 |
|
| 430 |
|
| 431 | class CfgLoopContext(object):
|
| 432 | """
|
| 433 | Context manager to make dealing with loops easier.
|
| 434 | """
|
| 435 |
|
| 436 | def __init__(self,
|
| 437 | cfg: ControlFlowGraph,
|
| 438 | entry: Optional[int] = None) -> None:
|
| 439 | self.cfg = cfg
|
| 440 | self.breaks = set({})
|
| 441 | if cfg is None:
|
| 442 | return
|
| 443 |
|
| 444 | self.entry = self.cfg._PushBlock(entry)
|
| 445 | self.exit = self.entry
|
| 446 |
|
| 447 | def AddBreak(self, statement: int) -> None:
|
| 448 | assert self.cfg
|
| 449 | self.breaks.add(statement)
|
| 450 | self.cfg.AddDeadend(statement)
|
| 451 |
|
| 452 | def AddContinue(self, statement: int) -> None:
|
| 453 | self.cfg.AddEdge(statement, self.entry)
|
| 454 | self.cfg.AddDeadend(statement)
|
| 455 |
|
| 456 | def __enter__(self) -> None:
|
| 457 | return self if self.cfg else None
|
| 458 |
|
| 459 | def __exit__(self, *args) -> None:
|
| 460 | if not self.cfg:
|
| 461 | return
|
| 462 |
|
| 463 | self.exit = self.cfg._PopBlock()
|
| 464 | self.cfg.AddEdge(self.exit, self.entry)
|
| 465 | for pred in self.cfg.predecessors:
|
| 466 | self.cfg.AddEdge(pred, self.entry)
|
| 467 |
|
| 468 | # If we had any breaks, arm the predecessor set with the current
|
| 469 | # statement and the break statements.
|
| 470 | if len(self.breaks):
|
| 471 | if len(self.cfg.block_stack):
|
| 472 | self.cfg.predecessors.add(self.cfg.block_stack[-1])
|
| 473 | else:
|
| 474 | self.cfg.predecessors.add(self.cfg.statement_counter)
|
| 475 |
|
| 476 | for b in self.breaks:
|
| 477 | self.cfg.deadends.remove(b)
|
| 478 | self.cfg.predecessors.add(b)
|
| 479 |
|
| 480 |
|
| 481 | class StackRoots(object):
|
| 482 | """
|
| 483 | Output of the souffle stack roots solver.
|
| 484 | """
|
| 485 |
|
| 486 | def __init__(self) -> None:
|
| 487 | self.root_tuples: set[tuple(SymbolPath, SymbolPath)] = set({})
|
| 488 |
|
| 489 |
|
| 490 | def needs_root(self, func: SymbolPath, reference: SymbolPath) -> bool:
|
| 491 | """
|
| 492 | Returns true if the given reference should have a stack root.
|
| 493 | """
|
| 494 | return (func, reference) in self.root_tuples
|
| 495 |
|
| 496 |
|
| 497 | def DumpControlFlowGraphs(cfgs: dict[str, ControlFlowGraph],
|
| 498 | facts_dir='_tmp/mycpp-facts') -> None:
|
| 499 | """
|
| 500 | Dump the given control flow graphs and associated facts into the given
|
| 501 | directory as text files that can be consumed by datalog.
|
| 502 | """
|
| 503 | edge_facts = '{}/cf_edge.facts'.format(facts_dir)
|
| 504 | fact_files = {}
|
| 505 | os.makedirs(facts_dir, exist_ok=True)
|
| 506 | with open(edge_facts, 'w') as cfg_f:
|
| 507 | for func, cfg in sorted(cfgs.items()):
|
| 508 | joined = join_name(func, delim='.')
|
| 509 | for (u, v) in sorted(cfg.edges):
|
| 510 | cfg_f.write('{}\t{}\t{}\n'.format(joined, u, v))
|
| 511 |
|
| 512 | for statement, facts in sorted(cfg.facts.items()):
|
| 513 | for fact in facts: # already sorted temporally
|
| 514 | fact_f = fact_files.get(fact.name())
|
| 515 | if not fact_f:
|
| 516 | fact_f = open(
|
| 517 | '{}/{}.facts'.format(facts_dir, fact.name()), 'w')
|
| 518 | fact_files[fact.name()] = fact_f
|
| 519 |
|
| 520 | fact_f.write(fact.Generate(joined, statement))
|
| 521 |
|
| 522 | for f in fact_files.values():
|
| 523 | f.close()
|
| 524 |
|
| 525 |
|
| 526 | def ComputeStackRoots(cfgs: dict[str, ControlFlowGraph],
|
| 527 | facts_dir:str = '_tmp/mycpp-facts',
|
| 528 | souffle_output_dir:str = '_tmp') -> StackRoots:
|
| 529 | """
|
| 530 | Run the the souffle stack roots solver and translate its output in a format
|
| 531 | that can be queried by cppgen_pass.
|
| 532 | """
|
| 533 | DumpControlFlowGraphs(cfgs, facts_dir=facts_dir)
|
| 534 | subprocess.check_call(
|
| 535 | [
|
| 536 | '_bin/datalog/dataflow',
|
| 537 | '-F', facts_dir,
|
| 538 | '-D', souffle_output_dir,
|
| 539 | ]
|
| 540 | )
|
| 541 |
|
| 542 | roots = StackRoots()
|
| 543 | with open('{}/stack_root_vars.tsv'.format(souffle_output_dir), 'r') as roots_f:
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| 544 | pat = re.compile(r'\$(.*)\((.*), (.*)\)')
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| 545 | for line in roots_f:
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| 546 | function, ref = line.split('\t')
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| 547 | m = pat.match(ref)
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| 548 | assert m.group(1) in ('LocalVariable', 'ObjectMember')
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| 549 | if m.group(1) == 'LocalVariable':
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| 550 | _, ref_func, var_name = m.groups()
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| 551 | assert ref_func == function
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| 552 | roots.root_tuples.add((split_py_name(function), (var_name,)))
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| 553 |
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| 554 | if m.group(1) == 'ObjectMember':
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| 555 | _, base_obj, member_name = m.groups()
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| 556 | roots.root_tuples.add((split_py_name(function),
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| 557 | split_py_name(base_obj) + (member_name,)))
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| 558 |
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| 559 | for t in roots.root_tuples:
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| 560 | print(t)
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| 561 |
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| 562 | return roots
|