1:- module( 2 da_frame, 3 [ 4 da_frame_stack/3, 5 da_hidden_frame/1, 6 da_frame_parent/2, 7 da_frame_clause/2, 8 da_frame_predicate_indicator/2, 9 da_alternative/2, 10 da_frame_alternative_frame/2, 11 da_frame_parent_pc/2, 12 da_frame_pc_stack/4, 13 da_frame_pc_source_span/3, 14 da_frame_clause_source_span/2, 15 da_frame_port_source_span/3, 16 da_frame_scopes/4, 17 da_frame_evaluate/4, 18 da_frame_variables_mapping/2, 19 da_referenced_variables/2, 20 da_frame_step_in_targets/4 21 ] 22 ). 23 24:- use_module(source). 25:- use_module(clause).
43:- meta_predicate da_frame_stack(, , ). 44:- meta_predicate da_frame_pc_stack(, , , ).
call(Goal,Id, PC, StackFrame) for every non-hidden frame in the current execution
stack starting after FrameId, with the frame's ID and saved PC as the first and
second argument to Goal respectively.
56:- det(da_frame_stack/3). 57da_frame_stack(Frame, Goal, Frames) :- 58 da_frame_parent(Frame, Parent), 59 da_frame_parent_pc(Frame, PC), 60 da_frame_pc_stack(Parent, PC, Goal, Frames). 61 62da_frame_pc_stack(null, _, _, []) :- !. 63da_frame_pc_stack(FrameId, _, Goal, Frames) :- 64 da_hidden_frame(FrameId), 65 !, 66 da_frame_stack(FrameId, Goal, Frames). 67da_frame_pc_stack(Frame, PC, Goal, [Head|Frames]) :- 68 call(Goal, Frame, PC, Head), 69 da_frame_stack(Frame, Goal, Frames).
null in case Frame is the
top frame.77:- det(da_frame_parent/2). 78da_frame_parent(Frame, Parent) :- 79 prolog_frame_attribute(Frame, parent, Parent), 80 !. 81da_frame_parent(_, null). 82 83 84:- det(da_frame_non_hidden_parent/2).(null, null) :- !. 86da_frame_non_hidden_parent(FrameId, ParentFrameId) :- 87 da_frame_parent(FrameId, ParentFrameId0), 88 da_frame_parent_non_hidden_parent(ParentFrameId0, ParentFrameId). 89 (null, null) :- !. 91da_frame_parent_non_hidden_parent(ParentFrameId0, ParentFrameId) :- 92 da_hidden_frame(ParentFrameId0), 93 !, 94 da_frame_non_hidden_parent(ParentFrameId0, ParentFrameId). 95da_frame_parent_non_hidden_parent(ParentFrameId, ParentFrameId).
null in case Frame does not specify a saved program counter.
The saved program counter determines from which point in the parent frame execution will resume once Frame is finished.
110:- det(da_frame_parent_pc/2). 111da_frame_parent_pc(Frame, PC) :- 112 prolog_frame_attribute(Frame, pc, PC), 113 da_frame_parent(Frame, Parent), 114 \+ da_hidden_frame(Parent), 115 !. 116da_frame_parent_pc(_, null).
122da_hidden_frame(Frame) :- 123 prolog_frame_attribute(Frame, hidden, true), !. 124da_hidden_frame(Frame) :- 125 prolog_frame_attribute(Frame, goal, Goal), 126 da_hidden_predicate(Goal), !. 127 (Goal) :- predicate_property(Goal, nodebug), !. 129da_hidden_predicate(Goal) :- predicate_property(Goal, hidden), !. 130da_hidden_predicate(swipl_debug_adapter:_).
138:- det(da_frame_predicate_indicator/2). 139da_frame_predicate_indicator(FrameId, PredicateIndicator) :- 140 prolog_frame_attribute(FrameId, predicate_indicator, PredicateIndicator).
none158:- det(da_alternative/2). 159da_alternative(ChoicePoint, Alternative) :- 160 prolog_choice_attribute(ChoicePoint, type, Type), 161 da_alternative(Type, ChoicePoint, Alternative). 162 163:- det(da_alternative/3). 164da_alternative(jump, ChoicePoint, jump(PC)) :- 165 !, 166 prolog_choice_attribute(ChoicePoint, pc, PC). 167da_alternative(clause, ChoicePoint, clause(Clause)) :- 168 !, 169 prolog_choice_attribute(ChoicePoint, clause, Clause). 170da_alternative(none, _, null) :- !. 171da_alternative(debug, _, null) :- !. 172da_alternative(catch, _, null) :- !. 173da_alternative(top, _, null) :- !. 174da_alternative(_, ChoicePoint, frame(Frame)) :- 175 !, 176 prolog_choice_attribute(ChoicePoint, frame, Frame).
null if FrameId does not have an alternative frame.184:- det(da_frame_alternative_frame/2). 185da_frame_alternative_frame(FrameId, frame(AlternativeFrameId)) :- 186 prolog_frame_attribute(FrameId, alternative, AlternativeFrameId), 187 !. 188da_frame_alternative_frame(_, null).
null in case Frame is executing a foreign predicate.196:- det(da_frame_clause/2). 197da_frame_clause(Frame, ClauseRef) :- 198 ( prolog_frame_attribute(Frame, clause, ClauseRef) 199 -> true 200 ; prolog_frame_attribute(Frame, goal, Goal), 201 qualified(Goal, Module, UGoal), 202 ( predicate_property(Module:UGoal, interpreted) 203 -> ( clause(Module:, _Body, ClauseRef) 204 -> true 205 ; functor(UGoal, Functor, Arity), 206 functor(UGoalTemplate, Functor, Arity), 207 clause(Module:, _Body, ClauseRef), ! 208 ) 209 ; ClauseRef = null 210 ) 211 ). 212 213:- det(da_frame_pc_source_span/3). 214da_frame_pc_source_span(_, null, null) :- !. 215da_frame_pc_source_span(FrameId, PC, SourceSpan) :- 216 da_frame_clause(FrameId, ClauseRef), 217 da_clause_source_span(ClauseRef, SourceSpan, [pc(PC)]). 218 219:- det(da_frame_port_source_span/3). 220da_frame_port_source_span(FrameId, Port, SourceSpan) :- 221 da_port_parent_pc(Port, PC), 222 !, 223 da_frame_parent_port_source_span(FrameId, FrameId, PC, Port, SourceSpan). 224da_frame_port_source_span(FrameId, Port, SourceSpan) :- 225 da_frame_parent_pc(FrameId, ParentPC), 226 da_frame_parent_pc_source_span(FrameId, ParentPC, Port, SourceSpan). 227 228da_port_parent_pc(cut_call(PC), PC) :- !. 229da_port_parent_pc(cut_exit(PC), PC) :- !. 230da_port_parent_pc(redo(0) , _ ) :- !, false. 231da_port_parent_pc(redo(PC) , PC) :- !. 232 233da_frame_parent_pc_source_span(FrameId, null, Port, SourceSpan) :- 234 !, 235 da_frame_port_clause_source_span(FrameId, Port, SourceSpan). 236da_frame_parent_pc_source_span(FrameId, ParentPC, Port, SourceSpan) :- 237 da_frame_parent(FrameId, ParentFrameId), 238 da_frame_parent_port_source_span(FrameId, ParentFrameId, ParentPC, Port, SourceSpan). 239 240da_frame_port_clause_source_span(FrameId, Port, SourceSpan) :- 241 da_frame_clause(FrameId, ClauseRef), 242 da_clause_source_span(ClauseRef, SourceSpan, [port(Port)]). 243 244da_frame_clause_source_span(FrameId, SourceSpan) :- 245 da_frame_clause(FrameId, ClauseRef), 246 da_clause_source_span(ClauseRef, SourceSpan). 247 248:- det(da_frame_parent_port_source_span/5). 249da_frame_parent_port_source_span(FrameId, null, _ParentPC, Port, SourceSpan) :- 250 !, 251 da_frame_port_clause_source_span(FrameId, Port, SourceSpan). 252da_frame_parent_port_source_span(FrameId, _ParentFrameId, _ParentPC, unify, SourceSpan) :- 253 !, 254 da_frame_clause(FrameId, ClauseRef), 255 da_clause_source_span(ClauseRef, SourceSpan, [port(unify)]). 256da_frame_parent_port_source_span(_FrameId, ParentFrameId, ParentPC, Port, SourceSpan) :- 257 da_frame_clause(ParentFrameId, ParentClauseRef), 258 da_clause_source_span(ParentClauseRef, SourceSpan, [pc(ParentPC), port(Port)]). 259 260 261:- det(da_frame_scopes/4). 262da_frame_scopes(ActiveFrameId, ActiveFrameId, Port, Scopes) :- 263 !, 264 da_active_frame_scopes(ActiveFrameId, Port, Scopes). 265da_frame_scopes(FrameId, _ActiveFrameId, _Port, Scopes) :- 266 da_stack_frame_scopes(FrameId, Scopes). 267 268da_stack_frame_scopes(FrameId, [ scope(Name, ArgumentsRef, SourceSpan), 269 scope("Local Bindings", LocalsRef, SourceSpan) 270 ] 271 ) :- 272 da_frame_variables_reference_type(FrameId, ArgumentsRef, arguments), 273 da_frame_variables_reference_type(FrameId, LocalsRef, locals), 274 da_frame_clause_source_span(FrameId, SourceSpan), 275 da_frame_predicate_indicator(FrameId, PI), 276 format(string(Name), "~w Arguments", PI). 277 278da_active_frame_scopes(FrameId, unify, Scopes) :- 279 !, 280 da_stack_frame_scopes(FrameId, Scopes). 281da_active_frame_scopes(FrameId, Port, [ scope(Name, ArgumentsRef, ArgumentsSpan), 282 scope("Local Bindings", LocalsRef, LocalsSpan) 283 ] 284 ) :- 285 !, 286 da_frame_non_hidden_parent(FrameId, ParentFrameId), 287 ( ParentFrameId == null 288 -> da_frame_variables_reference_type(FrameId, LocalsRef, locals), 289 da_frame_port_source_span(FrameId, Port, LocalsSpan) 290 ; da_frame_variables_reference_type(ParentFrameId, LocalsRef, locals), 291 da_frame_clause_source_span(ParentFrameId, LocalsSpan) 292 ), 293 da_frame_variables_reference_type(FrameId, ArgumentsRef, arguments), 294 da_frame_port_source_span(FrameId, Port, ArgumentsSpan), 295 da_frame_predicate_indicator(FrameId, PI), 296 format(string(Name), "~w Arguments", PI). 297 298 299:- use_module(library(clpfd)). 300 301:- det(da_frame_variables_reference_type/3). 302da_frame_variables_reference_type(FrameId, VariablesRef, Type) :- 303 da_variables_reference_frame_type_id(VariablesRef, FrameId, TypeId), 304 da_scope_type_id(Type, TypeId). 305 306da_variables_reference_frame_type_id(VariablesRef, FrameId, TypeId) :- 307 TypeId in 0..2, 308 VariablesRef #= (FrameId * 4) + TypeId. 309 310da_scope_type_id(arguments, 0) :- !. 311da_scope_type_id(locals, 1) :- !. 312da_scope_type_id(cached, 2). 313 314:- det(da_referenced_variables/2). 315da_referenced_variables(VariablesRef, Variables) :- 316 da_frame_variables_reference_type(FrameId, VariablesRef, Type), 317 ( Type == cached 318 -> da_variables_compound_arguments(Variables0, FrameId), 319 indexed_arguments(1, Variables0, Variables) 320 ; da_frame_clause(FrameId, ClauseRef), 321 ( ClauseRef == null 322 -> da_frame_goal_arity(FrameId, Arity), 323 findall('_', between(1, Arity, _), Args), 324 compound_name_arguments(VarNames, varnames, Args) 325 ; da_clause_variable_names(ClauseRef, VarNames) 326 ), 327 da_frame_variables(FrameId, Type, VarNames, Variables) 328 ). 329 330:- thread_local da_variables_compound_arguments/2. 331 332da_tracer_cached_compound_arguments(Arguments, Ref) :- 333 ( da_variables_compound_arguments(_, Ref0) 334 -> succ(Ref0, Ref) 335 ; Ref = 1 336 ), 337 asserta(da_variables_compound_arguments(Arguments, Ref)). 338 339:- det(indexed_arguments/3). 340indexed_arguments(_, [], []) :- !. 341indexed_arguments(I0, [H0|T0], [variable(Name, H, ChildrenReference)|T]) :- 342 indexed_argument_name(I0, Name), 343 da_term_factorized(H0, ChildrenReference, H), 344 succ(I0, I1), 345 indexed_arguments(I1, T0, T). 346 347indexed_argument_name(I, N) :- 348 format(atom(N), "arg(~w)", [I]). 349 350da_term_factorized(Var, 0, Name) :- 351 var(Var), format(string(Name), "~w", [Var]), 352 !. 353da_term_factorized([], 0, "[]") :- !. 354da_term_factorized(List, Ref, "[...]") :- 355 is_list(List), 356 !, 357 da_tracer_cached_compound_arguments(List, Ref0), 358 Ref is (Ref0 << 2) + 2. 359da_term_factorized(Compound, Ref, Name) :- 360 compound(Compound), 361 !, 362 compound_name_arguments(Compound, Functor, Arguments), 363 length(Arguments, Arity), 364 format(atom(Name), '~w/~w', [Functor, Arity]), 365 da_tracer_cached_compound_arguments(Arguments, Ref0), 366 Ref is (Ref0 << 2) + 2. 367da_term_factorized(Term0, 0, Term) :- 368 term_string(Term0, Term). 369 370:- det(da_frame_variables/4). 371da_frame_variables(Frame, Type, VarNames, Variables) :- 372 da_frame_goal_arity(Frame, Arity), 373 da_frame_arity_variables(Frame, Arity, Type, VarNames, Variables). 374 375:- det(da_frame_goal_arity/2). 376da_frame_goal_arity(FrameId, Arity) :- 377 prolog_frame_attribute(FrameId, predicate_indicator, PI), 378 qualified(PI, _, _Functor/Arity). 379 380da_frame_arity_variables(_, _, _, varnames, []) :- 381 % clause has no variables at all, hence VarNames is an atom 382 !. 383da_frame_arity_variables(_, 0, arguments, _, []) :- !. 384da_frame_arity_variables(Frame, Arity, arguments, VarNames, Variables) :- 385 !, 386 da_frame_arguments(Frame, 1, Arity, VarNames, Variables). 387da_frame_arity_variables(Frame, Arity, locals, VarNames, Variables) :- 388 !, 389 succ(Arity, I), 390 da_frame_locals(Frame, I, VarNames, Variables). 391 392:- det(da_frame_arguments/5). 393da_frame_arguments(Frame, I, Arity, VarNames, Variables) :- 394 ( I =< Arity 395 -> arg(I, VarNames, Name0), 396 ( Name0 == '_' 397 -> indexed_argument_name(I, Name) 398 ; Name = Name0 399 ), 400 prolog_frame_attribute(Frame, argument(I), Value0), 401 da_term_factorized(Value0, ChildrenReference, Value), 402 Variables = [variable(Name, Value, ChildrenReference)|T], 403 NI is I + 1, 404 da_frame_arguments(Frame, NI, Arity, VarNames, T) 405 ; Variables = [] 406 ). 407 408da_frame_locals(Frame, I, VarNames, Variables) :- 409 ( arg(I, VarNames, Name0) 410 -> ( Name0 == '_' 411 -> indexed_argument_name(I, Name) 412 ; Name = Name0 413 ), 414 ( prolog_frame_attribute(Frame, argument(I), Value0) 415 -> da_term_factorized(Value0, ChildrenReference, Value) 416 ; da_term_factorized(_, ChildrenReference, Value) 417 ), 418 Variables = [variable(Name, Value, ChildrenReference)|T], 419 NI is I + 1, 420 da_frame_locals(Frame, NI, VarNames, T) 421 ; Variables = [] 422 ). 423 424 425:- det(da_frame_evaluate/4). 426da_frame_evaluate(FrameId, SourceTerm, Result, Bindings) :- 427 read_term_from_atom(SourceTerm, Goal, [variable_names(Bindings)]), 428 da_frame_clause(FrameId, ClauseRef), 429 da_clause_variable_names(ClauseRef, ClauseVarNames), 430 da_frame_unify_variables(FrameId, ClauseVarNames, Bindings), 431 da_evaluate(Goal, Result). 432 433 434:- det(da_evaluate/2). 435da_evaluate(Goal, Result) :- 436 catch(Goal, Result, true), 437 !, 438 ( var(Result) 439 -> Result = true 440 ; true 441 ). 442da_evaluate(_, false). 443 444 445:- det(da_frame_unify_variables/3). 446da_frame_unify_variables(_FrameId, _ClauseVarNames, [ ]) :- !. 447da_frame_unify_variables( FrameId, ClauseVarNames, [VarName=Value|T]) :- !, 448 ( arg(I, ClauseVarNames, VarName) 449 -> prolog_frame_attribute(FrameId, argument(I), Value), 450 da_frame_unify_variables(FrameId, ClauseVarNames, T) 451 ; true 452 ), 453 da_frame_unify_variables(FrameId, ClauseVarNames, T). 454 455 456da_frame_variables_mapping(FrameId, Map) :- 457 da_frame_clause(FrameId, ClauseRef), 458 da_clause_variable_names(ClauseRef, ClauseVarNames), 459 ( ClauseVarNames == varnames 460 -> Map = [] 461 ; findall(Name=Value, 462 ( arg(I, ClauseVarNames, Name), 463 prolog_frame_attribute(FrameId, argument(I), Value) 464 ), 465 Map) 466 ). 467 468 469da_frame_step_in_targets(FrameId, FrameId, Choice, [step_in_target(0, null)|Targets]) :- 470 !, 471 da_alternative(Choice, Alternative), 472 da_alternative_step_in_targets(Alternative, Targets). 473da_frame_step_in_targets(_, _, _, []). 474 475 476da_alternative_step_in_targets(null, []) :- !. 477da_alternative_step_in_targets(Alt, [step_in_target(1, Alt)])
DAP library module for reasoning about Prolog frames
This module contains predicates for retrieving information about Prolog frames for debugging purposes. A Prolog frame is a runtime artifact that encapsulates the execution of a single goal.
Each frame has a unique temporarly ID represented as an integer. The predicates in this module generally take a frame ID as their first argument and unify their second argument with information about the denoted frame which is relevant for debugging purposes.