1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ D I S P -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2015, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING3. If not, go to -- 19-- http://www.gnu.org/licenses for a complete copy of the license. -- 20-- -- 21-- GNAT was originally developed by the GNAT team at New York University. -- 22-- Extensive contributions were provided by Ada Core Technologies Inc. -- 23-- -- 24------------------------------------------------------------------------------ 25 26with Atree; use Atree; 27with Debug; use Debug; 28with Elists; use Elists; 29with Einfo; use Einfo; 30with Exp_Disp; use Exp_Disp; 31with Exp_Util; use Exp_Util; 32with Exp_Ch7; use Exp_Ch7; 33with Exp_Tss; use Exp_Tss; 34with Errout; use Errout; 35with Lib.Xref; use Lib.Xref; 36with Namet; use Namet; 37with Nlists; use Nlists; 38with Nmake; use Nmake; 39with Opt; use Opt; 40with Output; use Output; 41with Restrict; use Restrict; 42with Rident; use Rident; 43with Sem; use Sem; 44with Sem_Aux; use Sem_Aux; 45with Sem_Ch3; use Sem_Ch3; 46with Sem_Ch6; use Sem_Ch6; 47with Sem_Ch8; use Sem_Ch8; 48with Sem_Eval; use Sem_Eval; 49with Sem_Type; use Sem_Type; 50with Sem_Util; use Sem_Util; 51with Snames; use Snames; 52with Sinfo; use Sinfo; 53with Targparm; use Targparm; 54with Tbuild; use Tbuild; 55with Uintp; use Uintp; 56 57package body Sem_Disp is 58 59 ----------------------- 60 -- Local Subprograms -- 61 ----------------------- 62 63 procedure Add_Dispatching_Operation 64 (Tagged_Type : Entity_Id; 65 New_Op : Entity_Id); 66 -- Add New_Op in the list of primitive operations of Tagged_Type 67 68 function Check_Controlling_Type 69 (T : Entity_Id; 70 Subp : Entity_Id) return Entity_Id; 71 -- T is the tagged type of a formal parameter or the result of Subp. 72 -- If the subprogram has a controlling parameter or result that matches 73 -- the type, then returns the tagged type of that parameter or result 74 -- (returning the designated tagged type in the case of an access 75 -- parameter); otherwise returns empty. 76 77 function Find_Hidden_Overridden_Primitive (S : Entity_Id) return Entity_Id; 78 -- [Ada 2012:AI-0125] Find an inherited hidden primitive of the dispatching 79 -- type of S that has the same name of S, a type-conformant profile, an 80 -- original corresponding operation O that is a primitive of a visible 81 -- ancestor of the dispatching type of S and O is visible at the point of 82 -- of declaration of S. If the entity is found the Alias of S is set to the 83 -- original corresponding operation S and its Overridden_Operation is set 84 -- to the found entity; otherwise return Empty. 85 -- 86 -- This routine does not search for non-hidden primitives since they are 87 -- covered by the normal Ada 2005 rules. 88 89 function Is_Inherited_Public_Operation (Op : Entity_Id) return Boolean; 90 -- Check whether a primitive operation is inherited from an operation 91 -- declared in the visible part of its package. 92 93 ------------------------------- 94 -- Add_Dispatching_Operation -- 95 ------------------------------- 96 97 procedure Add_Dispatching_Operation 98 (Tagged_Type : Entity_Id; 99 New_Op : Entity_Id) 100 is 101 List : constant Elist_Id := Primitive_Operations (Tagged_Type); 102 103 begin 104 -- The dispatching operation may already be on the list, if it is the 105 -- wrapper for an inherited function of a null extension (see Exp_Ch3 106 -- for the construction of function wrappers). The list of primitive 107 -- operations must not contain duplicates. 108 109 Append_Unique_Elmt (New_Op, List); 110 end Add_Dispatching_Operation; 111 112 --------------------------- 113 -- Covers_Some_Interface -- 114 --------------------------- 115 116 function Covers_Some_Interface (Prim : Entity_Id) return Boolean is 117 Tagged_Type : constant Entity_Id := Find_Dispatching_Type (Prim); 118 Elmt : Elmt_Id; 119 E : Entity_Id; 120 121 begin 122 pragma Assert (Is_Dispatching_Operation (Prim)); 123 124 -- Although this is a dispatching primitive we must check if its 125 -- dispatching type is available because it may be the primitive 126 -- of a private type not defined as tagged in its partial view. 127 128 if Present (Tagged_Type) and then Has_Interfaces (Tagged_Type) then 129 130 -- If the tagged type is frozen then the internal entities associated 131 -- with interfaces are available in the list of primitives of the 132 -- tagged type and can be used to speed up this search. 133 134 if Is_Frozen (Tagged_Type) then 135 Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); 136 while Present (Elmt) loop 137 E := Node (Elmt); 138 139 if Present (Interface_Alias (E)) 140 and then Alias (E) = Prim 141 then 142 return True; 143 end if; 144 145 Next_Elmt (Elmt); 146 end loop; 147 148 -- Otherwise we must collect all the interface primitives and check 149 -- if the Prim will override some interface primitive. 150 151 else 152 declare 153 Ifaces_List : Elist_Id; 154 Iface_Elmt : Elmt_Id; 155 Iface : Entity_Id; 156 Iface_Prim : Entity_Id; 157 158 begin 159 Collect_Interfaces (Tagged_Type, Ifaces_List); 160 Iface_Elmt := First_Elmt (Ifaces_List); 161 while Present (Iface_Elmt) loop 162 Iface := Node (Iface_Elmt); 163 164 Elmt := First_Elmt (Primitive_Operations (Iface)); 165 while Present (Elmt) loop 166 Iface_Prim := Node (Elmt); 167 168 if Chars (Iface) = Chars (Prim) 169 and then Is_Interface_Conformant 170 (Tagged_Type, Iface_Prim, Prim) 171 then 172 return True; 173 end if; 174 175 Next_Elmt (Elmt); 176 end loop; 177 178 Next_Elmt (Iface_Elmt); 179 end loop; 180 end; 181 end if; 182 end if; 183 184 return False; 185 end Covers_Some_Interface; 186 187 ------------------------------- 188 -- Check_Controlling_Formals -- 189 ------------------------------- 190 191 procedure Check_Controlling_Formals 192 (Typ : Entity_Id; 193 Subp : Entity_Id) 194 is 195 Formal : Entity_Id; 196 Ctrl_Type : Entity_Id; 197 198 begin 199 Formal := First_Formal (Subp); 200 while Present (Formal) loop 201 Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); 202 203 if Present (Ctrl_Type) then 204 205 -- When controlling type is concurrent and declared within a 206 -- generic or inside an instance use corresponding record type. 207 208 if Is_Concurrent_Type (Ctrl_Type) 209 and then Present (Corresponding_Record_Type (Ctrl_Type)) 210 then 211 Ctrl_Type := Corresponding_Record_Type (Ctrl_Type); 212 end if; 213 214 if Ctrl_Type = Typ then 215 Set_Is_Controlling_Formal (Formal); 216 217 -- Ada 2005 (AI-231): Anonymous access types that are used in 218 -- controlling parameters exclude null because it is necessary 219 -- to read the tag to dispatch, and null has no tag. 220 221 if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then 222 Set_Can_Never_Be_Null (Etype (Formal)); 223 Set_Is_Known_Non_Null (Etype (Formal)); 224 end if; 225 226 -- Check that the parameter's nominal subtype statically 227 -- matches the first subtype. 228 229 if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then 230 if not Subtypes_Statically_Match 231 (Typ, Designated_Type (Etype (Formal))) 232 then 233 Error_Msg_N 234 ("parameter subtype does not match controlling type", 235 Formal); 236 end if; 237 238 elsif not Subtypes_Statically_Match (Typ, Etype (Formal)) then 239 Error_Msg_N 240 ("parameter subtype does not match controlling type", 241 Formal); 242 end if; 243 244 if Present (Default_Value (Formal)) then 245 246 -- In Ada 2005, access parameters can have defaults 247 248 if Ekind (Etype (Formal)) = E_Anonymous_Access_Type 249 and then Ada_Version < Ada_2005 250 then 251 Error_Msg_N 252 ("default not allowed for controlling access parameter", 253 Default_Value (Formal)); 254 255 elsif not Is_Tag_Indeterminate (Default_Value (Formal)) then 256 Error_Msg_N 257 ("default expression must be a tag indeterminate" & 258 " function call", Default_Value (Formal)); 259 end if; 260 end if; 261 262 elsif Comes_From_Source (Subp) then 263 Error_Msg_N 264 ("operation can be dispatching in only one type", Subp); 265 end if; 266 end if; 267 268 Next_Formal (Formal); 269 end loop; 270 271 if Ekind_In (Subp, E_Function, E_Generic_Function) then 272 Ctrl_Type := Check_Controlling_Type (Etype (Subp), Subp); 273 274 if Present (Ctrl_Type) then 275 if Ctrl_Type = Typ then 276 Set_Has_Controlling_Result (Subp); 277 278 -- Check that result subtype statically matches first subtype 279 -- (Ada 2005): Subp may have a controlling access result. 280 281 if Subtypes_Statically_Match (Typ, Etype (Subp)) 282 or else (Ekind (Etype (Subp)) = E_Anonymous_Access_Type 283 and then 284 Subtypes_Statically_Match 285 (Typ, Designated_Type (Etype (Subp)))) 286 then 287 null; 288 289 else 290 Error_Msg_N 291 ("result subtype does not match controlling type", Subp); 292 end if; 293 294 elsif Comes_From_Source (Subp) then 295 Error_Msg_N 296 ("operation can be dispatching in only one type", Subp); 297 end if; 298 end if; 299 end if; 300 end Check_Controlling_Formals; 301 302 ---------------------------- 303 -- Check_Controlling_Type -- 304 ---------------------------- 305 306 function Check_Controlling_Type 307 (T : Entity_Id; 308 Subp : Entity_Id) return Entity_Id 309 is 310 Tagged_Type : Entity_Id := Empty; 311 312 begin 313 if Is_Tagged_Type (T) then 314 if Is_First_Subtype (T) then 315 Tagged_Type := T; 316 else 317 Tagged_Type := Base_Type (T); 318 end if; 319 320 elsif Ekind (T) = E_Anonymous_Access_Type 321 and then Is_Tagged_Type (Designated_Type (T)) 322 then 323 if Ekind (Designated_Type (T)) /= E_Incomplete_Type then 324 if Is_First_Subtype (Designated_Type (T)) then 325 Tagged_Type := Designated_Type (T); 326 else 327 Tagged_Type := Base_Type (Designated_Type (T)); 328 end if; 329 330 -- Ada 2005: an incomplete type can be tagged. An operation with an 331 -- access parameter of the type is dispatching. 332 333 elsif Scope (Designated_Type (T)) = Current_Scope then 334 Tagged_Type := Designated_Type (T); 335 336 -- Ada 2005 (AI-50217) 337 338 elsif From_Limited_With (Designated_Type (T)) 339 and then Present (Non_Limited_View (Designated_Type (T))) 340 and then Scope (Designated_Type (T)) = Scope (Subp) 341 then 342 if Is_First_Subtype (Non_Limited_View (Designated_Type (T))) then 343 Tagged_Type := Non_Limited_View (Designated_Type (T)); 344 else 345 Tagged_Type := Base_Type (Non_Limited_View 346 (Designated_Type (T))); 347 end if; 348 end if; 349 end if; 350 351 if No (Tagged_Type) or else Is_Class_Wide_Type (Tagged_Type) then 352 return Empty; 353 354 -- The dispatching type and the primitive operation must be defined in 355 -- the same scope, except in the case of internal operations and formal 356 -- abstract subprograms. 357 358 elsif ((Scope (Subp) = Scope (Tagged_Type) or else Is_Internal (Subp)) 359 and then (not Is_Generic_Type (Tagged_Type) 360 or else not Comes_From_Source (Subp))) 361 or else 362 (Is_Formal_Subprogram (Subp) and then Is_Abstract_Subprogram (Subp)) 363 or else 364 (Nkind (Parent (Parent (Subp))) = N_Subprogram_Renaming_Declaration 365 and then 366 Present (Corresponding_Formal_Spec (Parent (Parent (Subp)))) 367 and then 368 Is_Abstract_Subprogram (Subp)) 369 then 370 return Tagged_Type; 371 372 else 373 return Empty; 374 end if; 375 end Check_Controlling_Type; 376 377 ---------------------------- 378 -- Check_Dispatching_Call -- 379 ---------------------------- 380 381 procedure Check_Dispatching_Call (N : Node_Id) is 382 Loc : constant Source_Ptr := Sloc (N); 383 Actual : Node_Id; 384 Formal : Entity_Id; 385 Control : Node_Id := Empty; 386 Func : Entity_Id; 387 Subp_Entity : Entity_Id; 388 Indeterm_Ancestor_Call : Boolean := False; 389 Indeterm_Ctrl_Type : Entity_Id; 390 391 Static_Tag : Node_Id := Empty; 392 -- If a controlling formal has a statically tagged actual, the tag of 393 -- this actual is to be used for any tag-indeterminate actual. 394 395 procedure Check_Direct_Call; 396 -- In the case when the controlling actual is a class-wide type whose 397 -- root type's completion is a task or protected type, the call is in 398 -- fact direct. This routine detects the above case and modifies the 399 -- call accordingly. 400 401 procedure Check_Dispatching_Context; 402 -- If the call is tag-indeterminate and the entity being called is 403 -- abstract, verify that the context is a call that will eventually 404 -- provide a tag for dispatching, or has provided one already. 405 406 ----------------------- 407 -- Check_Direct_Call -- 408 ----------------------- 409 410 procedure Check_Direct_Call is 411 Typ : Entity_Id := Etype (Control); 412 413 function Is_User_Defined_Equality (Id : Entity_Id) return Boolean; 414 -- Determine whether an entity denotes a user-defined equality 415 416 ------------------------------ 417 -- Is_User_Defined_Equality -- 418 ------------------------------ 419 420 function Is_User_Defined_Equality (Id : Entity_Id) return Boolean is 421 begin 422 return 423 Ekind (Id) = E_Function 424 and then Chars (Id) = Name_Op_Eq 425 and then Comes_From_Source (Id) 426 427 -- Internally generated equalities have a full type declaration 428 -- as their parent. 429 430 and then Nkind (Parent (Id)) = N_Function_Specification; 431 end Is_User_Defined_Equality; 432 433 -- Start of processing for Check_Direct_Call 434 435 begin 436 -- Predefined primitives do not receive wrappers since they are built 437 -- from scratch for the corresponding record of synchronized types. 438 -- Equality is in general predefined, but is excluded from the check 439 -- when it is user-defined. 440 441 if Is_Predefined_Dispatching_Operation (Subp_Entity) 442 and then not Is_User_Defined_Equality (Subp_Entity) 443 then 444 return; 445 end if; 446 447 if Is_Class_Wide_Type (Typ) then 448 Typ := Root_Type (Typ); 449 end if; 450 451 if Is_Private_Type (Typ) and then Present (Full_View (Typ)) then 452 Typ := Full_View (Typ); 453 end if; 454 455 if Is_Concurrent_Type (Typ) 456 and then 457 Present (Corresponding_Record_Type (Typ)) 458 then 459 Typ := Corresponding_Record_Type (Typ); 460 461 -- The concurrent record's list of primitives should contain a 462 -- wrapper for the entity of the call, retrieve it. 463 464 declare 465 Prim : Entity_Id; 466 Prim_Elmt : Elmt_Id; 467 Wrapper_Found : Boolean := False; 468 469 begin 470 Prim_Elmt := First_Elmt (Primitive_Operations (Typ)); 471 while Present (Prim_Elmt) loop 472 Prim := Node (Prim_Elmt); 473 474 if Is_Primitive_Wrapper (Prim) 475 and then Wrapped_Entity (Prim) = Subp_Entity 476 then 477 Wrapper_Found := True; 478 exit; 479 end if; 480 481 Next_Elmt (Prim_Elmt); 482 end loop; 483 484 -- A primitive declared between two views should have a 485 -- corresponding wrapper. 486 487 pragma Assert (Wrapper_Found); 488 489 -- Modify the call by setting the proper entity 490 491 Set_Entity (Name (N), Prim); 492 end; 493 end if; 494 end Check_Direct_Call; 495 496 ------------------------------- 497 -- Check_Dispatching_Context -- 498 ------------------------------- 499 500 procedure Check_Dispatching_Context is 501 Subp : constant Entity_Id := Entity (Name (N)); 502 Typ : constant Entity_Id := Etype (Subp); 503 Par : Node_Id; 504 505 procedure Abstract_Context_Error; 506 -- Error for abstract call dispatching on result is not dispatching 507 508 ---------------------------- 509 -- Abstract_Context_Error -- 510 ---------------------------- 511 512 procedure Abstract_Context_Error is 513 begin 514 if Ekind (Subp) = E_Function then 515 Error_Msg_N 516 ("call to abstract function must be dispatching", N); 517 518 -- This error can occur for a procedure in the case of a call to 519 -- an abstract formal procedure with a statically tagged operand. 520 521 else 522 Error_Msg_N 523 ("call to abstract procedure must be dispatching", 524 N); 525 end if; 526 end Abstract_Context_Error; 527 528 -- Start of processing for Check_Dispatching_Context 529 530 begin 531 if Is_Abstract_Subprogram (Subp) 532 and then No (Controlling_Argument (N)) 533 then 534 if Present (Alias (Subp)) 535 and then not Is_Abstract_Subprogram (Alias (Subp)) 536 and then No (DTC_Entity (Subp)) 537 then 538 -- Private overriding of inherited abstract operation, call is 539 -- legal. 540 541 Set_Entity (Name (N), Alias (Subp)); 542 return; 543 544 -- An obscure special case: a null procedure may have a class- 545 -- wide pre/postcondition that includes a call to an abstract 546 -- subp. Calls within the expression may not have been rewritten 547 -- as dispatching calls yet, because the null body appears in 548 -- the current declarative part. The expression will be properly 549 -- rewritten/reanalyzed when the postcondition procedure is built. 550 551 -- Similarly, if this is a pre/postcondition for an abstract 552 -- subprogram, it may call another abstract function which is 553 -- a primitive of an abstract type. The call is non-dispatching 554 -- but will be legal in overridings of the operation. 555 556 elsif In_Spec_Expression 557 and then Is_Subprogram (Current_Scope) 558 and then 559 ((Nkind (Parent (Current_Scope)) = N_Procedure_Specification 560 and then Null_Present (Parent (Current_Scope))) 561 or else Is_Abstract_Subprogram (Current_Scope)) 562 then 563 null; 564 565 elsif Ekind (Current_Scope) = E_Function 566 and then Nkind (Unit_Declaration_Node (Current_Scope)) = 567 N_Generic_Subprogram_Declaration 568 then 569 null; 570 571 else 572 -- We need to determine whether the context of the call 573 -- provides a tag to make the call dispatching. This requires 574 -- the call to be the actual in an enclosing call, and that 575 -- actual must be controlling. If the call is an operand of 576 -- equality, the other operand must not ve abstract. 577 578 if not Is_Tagged_Type (Typ) 579 and then not 580 (Ekind (Typ) = E_Anonymous_Access_Type 581 and then Is_Tagged_Type (Designated_Type (Typ))) 582 then 583 Abstract_Context_Error; 584 return; 585 end if; 586 587 Par := Parent (N); 588 589 if Nkind (Par) = N_Parameter_Association then 590 Par := Parent (Par); 591 end if; 592 593 while Present (Par) loop 594 if Nkind_In (Par, N_Function_Call, 595 N_Procedure_Call_Statement) 596 and then Is_Entity_Name (Name (Par)) 597 then 598 declare 599 A : Node_Id; 600 F : Entity_Id; 601 602 begin 603 -- Find formal for which call is the actual. 604 605 F := First_Formal (Entity (Name (Par))); 606 A := First_Actual (Par); 607 while Present (F) loop 608 if Is_Controlling_Formal (F) 609 and then (N = A or else Parent (N) = A) 610 then 611 return; 612 end if; 613 614 Next_Formal (F); 615 Next_Actual (A); 616 end loop; 617 618 Error_Msg_N 619 ("call to abstract function must be dispatching", N); 620 return; 621 end; 622 623 -- For equalitiy operators, one of the operands must be 624 -- statically or dynamically tagged. 625 626 elsif Nkind_In (Par, N_Op_Eq, N_Op_Ne) then 627 if N = Right_Opnd (Par) 628 and then Is_Tag_Indeterminate (Left_Opnd (Par)) 629 then 630 Abstract_Context_Error; 631 632 elsif N = Left_Opnd (Par) 633 and then Is_Tag_Indeterminate (Right_Opnd (Par)) 634 then 635 Abstract_Context_Error; 636 end if; 637 638 return; 639 640 elsif Nkind (Par) = N_Assignment_Statement then 641 return; 642 643 elsif Nkind (Par) = N_Qualified_Expression 644 or else Nkind (Par) = N_Unchecked_Type_Conversion 645 then 646 Par := Parent (Par); 647 648 else 649 Abstract_Context_Error; 650 return; 651 end if; 652 end loop; 653 end if; 654 end if; 655 end Check_Dispatching_Context; 656 657 -- Start of processing for Check_Dispatching_Call 658 659 begin 660 -- Find a controlling argument, if any 661 662 if Present (Parameter_Associations (N)) then 663 Subp_Entity := Entity (Name (N)); 664 665 Actual := First_Actual (N); 666 Formal := First_Formal (Subp_Entity); 667 while Present (Actual) loop 668 Control := Find_Controlling_Arg (Actual); 669 exit when Present (Control); 670 671 -- Check for the case where the actual is a tag-indeterminate call 672 -- whose result type is different than the tagged type associated 673 -- with the containing call, but is an ancestor of the type. 674 675 if Is_Controlling_Formal (Formal) 676 and then Is_Tag_Indeterminate (Actual) 677 and then Base_Type (Etype (Actual)) /= Base_Type (Etype (Formal)) 678 and then Is_Ancestor (Etype (Actual), Etype (Formal)) 679 then 680 Indeterm_Ancestor_Call := True; 681 Indeterm_Ctrl_Type := Etype (Formal); 682 683 -- If the formal is controlling but the actual is not, the type 684 -- of the actual is statically known, and may be used as the 685 -- controlling tag for some other tag-indeterminate actual. 686 687 elsif Is_Controlling_Formal (Formal) 688 and then Is_Entity_Name (Actual) 689 and then Is_Tagged_Type (Etype (Actual)) 690 then 691 Static_Tag := Actual; 692 end if; 693 694 Next_Actual (Actual); 695 Next_Formal (Formal); 696 end loop; 697 698 -- If the call doesn't have a controlling actual but does have an 699 -- indeterminate actual that requires dispatching treatment, then an 700 -- object is needed that will serve as the controlling argument for 701 -- a dispatching call on the indeterminate actual. This can only 702 -- occur in the unusual situation of a default actual given by 703 -- a tag-indeterminate call and where the type of the call is an 704 -- ancestor of the type associated with a containing call to an 705 -- inherited operation (see AI-239). 706 707 -- Rather than create an object of the tagged type, which would 708 -- be problematic for various reasons (default initialization, 709 -- discriminants), the tag of the containing call's associated 710 -- tagged type is directly used to control the dispatching. 711 712 if No (Control) 713 and then Indeterm_Ancestor_Call 714 and then No (Static_Tag) 715 then 716 Control := 717 Make_Attribute_Reference (Loc, 718 Prefix => New_Occurrence_Of (Indeterm_Ctrl_Type, Loc), 719 Attribute_Name => Name_Tag); 720 721 Analyze (Control); 722 end if; 723 724 if Present (Control) then 725 726 -- Verify that no controlling arguments are statically tagged 727 728 if Debug_Flag_E then 729 Write_Str ("Found Dispatching call"); 730 Write_Int (Int (N)); 731 Write_Eol; 732 end if; 733 734 Actual := First_Actual (N); 735 while Present (Actual) loop 736 if Actual /= Control then 737 738 if not Is_Controlling_Actual (Actual) then 739 null; -- Can be anything 740 741 elsif Is_Dynamically_Tagged (Actual) then 742 null; -- Valid parameter 743 744 elsif Is_Tag_Indeterminate (Actual) then 745 746 -- The tag is inherited from the enclosing call (the node 747 -- we are currently analyzing). Explicitly expand the 748 -- actual, since the previous call to Expand (from 749 -- Resolve_Call) had no way of knowing about the 750 -- required dispatching. 751 752 Propagate_Tag (Control, Actual); 753 754 else 755 Error_Msg_N 756 ("controlling argument is not dynamically tagged", 757 Actual); 758 return; 759 end if; 760 end if; 761 762 Next_Actual (Actual); 763 end loop; 764 765 -- Mark call as a dispatching call 766 767 Set_Controlling_Argument (N, Control); 768 Check_Restriction (No_Dispatching_Calls, N); 769 770 -- The dispatching call may need to be converted into a direct 771 -- call in certain cases. 772 773 Check_Direct_Call; 774 775 -- If there is a statically tagged actual and a tag-indeterminate 776 -- call to a function of the ancestor (such as that provided by a 777 -- default), then treat this as a dispatching call and propagate 778 -- the tag to the tag-indeterminate call(s). 779 780 elsif Present (Static_Tag) and then Indeterm_Ancestor_Call then 781 Control := 782 Make_Attribute_Reference (Loc, 783 Prefix => 784 New_Occurrence_Of (Etype (Static_Tag), Loc), 785 Attribute_Name => Name_Tag); 786 787 Analyze (Control); 788 789 Actual := First_Actual (N); 790 Formal := First_Formal (Subp_Entity); 791 while Present (Actual) loop 792 if Is_Tag_Indeterminate (Actual) 793 and then Is_Controlling_Formal (Formal) 794 then 795 Propagate_Tag (Control, Actual); 796 end if; 797 798 Next_Actual (Actual); 799 Next_Formal (Formal); 800 end loop; 801 802 Check_Dispatching_Context; 803 804 else 805 -- The call is not dispatching, so check that there aren't any 806 -- tag-indeterminate abstract calls left. 807 808 Actual := First_Actual (N); 809 while Present (Actual) loop 810 if Is_Tag_Indeterminate (Actual) then 811 812 -- Function call case 813 814 if Nkind (Original_Node (Actual)) = N_Function_Call then 815 Func := Entity (Name (Original_Node (Actual))); 816 817 -- If the actual is an attribute then it can't be abstract 818 -- (the only current case of a tag-indeterminate attribute 819 -- is the stream Input attribute). 820 821 elsif 822 Nkind (Original_Node (Actual)) = N_Attribute_Reference 823 then 824 Func := Empty; 825 826 -- Only other possibility is a qualified expression whose 827 -- constituent expression is itself a call. 828 829 else 830 Func := 831 Entity (Name 832 (Original_Node 833 (Expression (Original_Node (Actual))))); 834 end if; 835 836 if Present (Func) and then Is_Abstract_Subprogram (Func) then 837 Error_Msg_N 838 ("call to abstract function must be dispatching", N); 839 end if; 840 end if; 841 842 Next_Actual (Actual); 843 end loop; 844 845 Check_Dispatching_Context; 846 end if; 847 848 else 849 -- If dispatching on result, the enclosing call, if any, will 850 -- determine the controlling argument. Otherwise this is the 851 -- primitive operation of the root type. 852 853 Check_Dispatching_Context; 854 end if; 855 end Check_Dispatching_Call; 856 857 --------------------------------- 858 -- Check_Dispatching_Operation -- 859 --------------------------------- 860 861 procedure Check_Dispatching_Operation (Subp, Old_Subp : Entity_Id) is 862 Tagged_Type : Entity_Id; 863 Has_Dispatching_Parent : Boolean := False; 864 Body_Is_Last_Primitive : Boolean := False; 865 Ovr_Subp : Entity_Id := Empty; 866 867 begin 868 if not Ekind_In (Subp, E_Procedure, E_Function) then 869 return; 870 end if; 871 872 Set_Is_Dispatching_Operation (Subp, False); 873 Tagged_Type := Find_Dispatching_Type (Subp); 874 875 -- Ada 2005 (AI-345): Use the corresponding record (if available). 876 -- Required because primitives of concurrent types are attached 877 -- to the corresponding record (not to the concurrent type). 878 879 if Ada_Version >= Ada_2005 880 and then Present (Tagged_Type) 881 and then Is_Concurrent_Type (Tagged_Type) 882 and then Present (Corresponding_Record_Type (Tagged_Type)) 883 then 884 Tagged_Type := Corresponding_Record_Type (Tagged_Type); 885 end if; 886 887 -- (AI-345): The task body procedure is not a primitive of the tagged 888 -- type 889 890 if Present (Tagged_Type) 891 and then Is_Concurrent_Record_Type (Tagged_Type) 892 and then Present (Corresponding_Concurrent_Type (Tagged_Type)) 893 and then Is_Task_Type (Corresponding_Concurrent_Type (Tagged_Type)) 894 and then Subp = Get_Task_Body_Procedure 895 (Corresponding_Concurrent_Type (Tagged_Type)) 896 then 897 return; 898 end if; 899 900 -- If Subp is derived from a dispatching operation then it should 901 -- always be treated as dispatching. In this case various checks 902 -- below will be bypassed. Makes sure that late declarations for 903 -- inherited private subprograms are treated as dispatching, even 904 -- if the associated tagged type is already frozen. 905 906 Has_Dispatching_Parent := 907 Present (Alias (Subp)) 908 and then Is_Dispatching_Operation (Alias (Subp)); 909 910 if No (Tagged_Type) then 911 912 -- Ada 2005 (AI-251): Check that Subp is not a primitive associated 913 -- with an abstract interface type unless the interface acts as a 914 -- parent type in a derivation. If the interface type is a formal 915 -- type then the operation is not primitive and therefore legal. 916 917 declare 918 E : Entity_Id; 919 Typ : Entity_Id; 920 921 begin 922 E := First_Entity (Subp); 923 while Present (E) loop 924 925 -- For an access parameter, check designated type 926 927 if Ekind (Etype (E)) = E_Anonymous_Access_Type then 928 Typ := Designated_Type (Etype (E)); 929 else 930 Typ := Etype (E); 931 end if; 932 933 if Comes_From_Source (Subp) 934 and then Is_Interface (Typ) 935 and then not Is_Class_Wide_Type (Typ) 936 and then not Is_Derived_Type (Typ) 937 and then not Is_Generic_Type (Typ) 938 and then not In_Instance 939 then 940 Error_Msg_N ("??declaration of& is too late!", Subp); 941 Error_Msg_NE -- CODEFIX?? 942 ("\??spec should appear immediately after declaration " 943 & "of & !", Subp, Typ); 944 exit; 945 end if; 946 947 Next_Entity (E); 948 end loop; 949 950 -- In case of functions check also the result type 951 952 if Ekind (Subp) = E_Function then 953 if Is_Access_Type (Etype (Subp)) then 954 Typ := Designated_Type (Etype (Subp)); 955 else 956 Typ := Etype (Subp); 957 end if; 958 959 -- The following should be better commented, especially since 960 -- we just added several new conditions here ??? 961 962 if Comes_From_Source (Subp) 963 and then Is_Interface (Typ) 964 and then not Is_Class_Wide_Type (Typ) 965 and then not Is_Derived_Type (Typ) 966 and then not Is_Generic_Type (Typ) 967 and then not In_Instance 968 then 969 Error_Msg_N ("??declaration of& is too late!", Subp); 970 Error_Msg_NE 971 ("\??spec should appear immediately after declaration " 972 & "of & !", Subp, Typ); 973 end if; 974 end if; 975 end; 976 977 return; 978 979 -- The subprograms build internally after the freezing point (such as 980 -- init procs, interface thunks, type support subprograms, and Offset 981 -- to top functions for accessing interface components in variable 982 -- size tagged types) are not primitives. 983 984 elsif Is_Frozen (Tagged_Type) 985 and then not Comes_From_Source (Subp) 986 and then not Has_Dispatching_Parent 987 then 988 -- Complete decoration of internally built subprograms that override 989 -- a dispatching primitive. These entities correspond with the 990 -- following cases: 991 992 -- 1. Ada 2005 (AI-391): Wrapper functions built by the expander 993 -- to override functions of nonabstract null extensions. These 994 -- primitives were added to the list of primitives of the tagged 995 -- type by Make_Controlling_Function_Wrappers. However, attribute 996 -- Is_Dispatching_Operation must be set to true. 997 998 -- 2. Ada 2005 (AI-251): Wrapper procedures of null interface 999 -- primitives. 1000 1001 -- 3. Subprograms associated with stream attributes (built by 1002 -- New_Stream_Subprogram) 1003 1004 if Present (Old_Subp) 1005 and then Present (Overridden_Operation (Subp)) 1006 and then Is_Dispatching_Operation (Old_Subp) 1007 then 1008 pragma Assert 1009 ((Ekind (Subp) = E_Function 1010 and then Is_Dispatching_Operation (Old_Subp) 1011 and then Is_Null_Extension (Base_Type (Etype (Subp)))) 1012 or else 1013 (Ekind (Subp) = E_Procedure 1014 and then Is_Dispatching_Operation (Old_Subp) 1015 and then Present (Alias (Old_Subp)) 1016 and then Is_Null_Interface_Primitive 1017 (Ultimate_Alias (Old_Subp))) 1018 or else Get_TSS_Name (Subp) = TSS_Stream_Read 1019 or else Get_TSS_Name (Subp) = TSS_Stream_Write); 1020 1021 Check_Controlling_Formals (Tagged_Type, Subp); 1022 Override_Dispatching_Operation (Tagged_Type, Old_Subp, Subp); 1023 Set_Is_Dispatching_Operation (Subp); 1024 end if; 1025 1026 return; 1027 1028 -- The operation may be a child unit, whose scope is the defining 1029 -- package, but which is not a primitive operation of the type. 1030 1031 elsif Is_Child_Unit (Subp) then 1032 return; 1033 1034 -- If the subprogram is not defined in a package spec, the only case 1035 -- where it can be a dispatching op is when it overrides an operation 1036 -- before the freezing point of the type. 1037 1038 elsif ((not Is_Package_Or_Generic_Package (Scope (Subp))) 1039 or else In_Package_Body (Scope (Subp))) 1040 and then not Has_Dispatching_Parent 1041 then 1042 if not Comes_From_Source (Subp) 1043 or else (Present (Old_Subp) and then not Is_Frozen (Tagged_Type)) 1044 then 1045 null; 1046 1047 -- If the type is already frozen, the overriding is not allowed 1048 -- except when Old_Subp is not a dispatching operation (which can 1049 -- occur when Old_Subp was inherited by an untagged type). However, 1050 -- a body with no previous spec freezes the type *after* its 1051 -- declaration, and therefore is a legal overriding (unless the type 1052 -- has already been frozen). Only the first such body is legal. 1053 1054 elsif Present (Old_Subp) 1055 and then Is_Dispatching_Operation (Old_Subp) 1056 then 1057 if Comes_From_Source (Subp) 1058 and then 1059 (Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Body 1060 or else Nkind (Unit_Declaration_Node (Subp)) in N_Body_Stub) 1061 then 1062 declare 1063 Subp_Body : constant Node_Id := Unit_Declaration_Node (Subp); 1064 Decl_Item : Node_Id; 1065 1066 begin 1067 -- ??? The checks here for whether the type has been frozen 1068 -- prior to the new body are not complete. It's not simple 1069 -- to check frozenness at this point since the body has 1070 -- already caused the type to be prematurely frozen in 1071 -- Analyze_Declarations, but we're forced to recheck this 1072 -- here because of the odd rule interpretation that allows 1073 -- the overriding if the type wasn't frozen prior to the 1074 -- body. The freezing action should probably be delayed 1075 -- until after the spec is seen, but that's a tricky 1076 -- change to the delicate freezing code. 1077 1078 -- Look at each declaration following the type up until the 1079 -- new subprogram body. If any of the declarations is a body 1080 -- then the type has been frozen already so the overriding 1081 -- primitive is illegal. 1082 1083 Decl_Item := Next (Parent (Tagged_Type)); 1084 while Present (Decl_Item) 1085 and then (Decl_Item /= Subp_Body) 1086 loop 1087 if Comes_From_Source (Decl_Item) 1088 and then (Nkind (Decl_Item) in N_Proper_Body 1089 or else Nkind (Decl_Item) in N_Body_Stub) 1090 then 1091 Error_Msg_N ("overriding of& is too late!", Subp); 1092 Error_Msg_N 1093 ("\spec should appear immediately after the type!", 1094 Subp); 1095 exit; 1096 end if; 1097 1098 Next (Decl_Item); 1099 end loop; 1100 1101 -- If the subprogram doesn't follow in the list of 1102 -- declarations including the type then the type has 1103 -- definitely been frozen already and the body is illegal. 1104 1105 if No (Decl_Item) then 1106 Error_Msg_N ("overriding of& is too late!", Subp); 1107 Error_Msg_N 1108 ("\spec should appear immediately after the type!", 1109 Subp); 1110 1111 elsif Is_Frozen (Subp) then 1112 1113 -- The subprogram body declares a primitive operation. 1114 -- If the subprogram is already frozen, we must update 1115 -- its dispatching information explicitly here. The 1116 -- information is taken from the overridden subprogram. 1117 -- We must also generate a cross-reference entry because 1118 -- references to other primitives were already created 1119 -- when type was frozen. 1120 1121 Body_Is_Last_Primitive := True; 1122 1123 if Present (DTC_Entity (Old_Subp)) then 1124 Set_DTC_Entity (Subp, DTC_Entity (Old_Subp)); 1125 Set_DT_Position_Value (Subp, DT_Position (Old_Subp)); 1126 1127 if not Restriction_Active (No_Dispatching_Calls) then 1128 if Building_Static_DT (Tagged_Type) then 1129 1130 -- If the static dispatch table has not been 1131 -- built then there is nothing else to do now; 1132 -- otherwise we notify that we cannot build the 1133 -- static dispatch table. 1134 1135 if Has_Dispatch_Table (Tagged_Type) then 1136 Error_Msg_N 1137 ("overriding of& is too late for building " 1138 & " static dispatch tables!", Subp); 1139 Error_Msg_N 1140 ("\spec should appear immediately after " 1141 & "the type!", Subp); 1142 end if; 1143 1144 -- No code required to register primitives in VM 1145 -- targets 1146 1147 elsif VM_Target /= No_VM then 1148 null; 1149 1150 else 1151 Insert_Actions_After (Subp_Body, 1152 Register_Primitive (Sloc (Subp_Body), 1153 Prim => Subp)); 1154 end if; 1155 1156 -- Indicate that this is an overriding operation, 1157 -- and replace the overridden entry in the list of 1158 -- primitive operations, which is used for xref 1159 -- generation subsequently. 1160 1161 Generate_Reference (Tagged_Type, Subp, 'P', False); 1162 Override_Dispatching_Operation 1163 (Tagged_Type, Old_Subp, Subp); 1164 end if; 1165 end if; 1166 end if; 1167 end; 1168 1169 else 1170 Error_Msg_N ("overriding of& is too late!", Subp); 1171 Error_Msg_N 1172 ("\subprogram spec should appear immediately after the type!", 1173 Subp); 1174 end if; 1175 1176 -- If the type is not frozen yet and we are not in the overriding 1177 -- case it looks suspiciously like an attempt to define a primitive 1178 -- operation, which requires the declaration to be in a package spec 1179 -- (3.2.3(6)). Only report cases where the type and subprogram are 1180 -- in the same declaration list (by checking the enclosing parent 1181 -- declarations), to avoid spurious warnings on subprograms in 1182 -- instance bodies when the type is declared in the instance spec 1183 -- but hasn't been frozen by the instance body. 1184 1185 elsif not Is_Frozen (Tagged_Type) 1186 and then In_Same_List (Parent (Tagged_Type), Parent (Parent (Subp))) 1187 then 1188 Error_Msg_N 1189 ("??not dispatching (must be defined in a package spec)", Subp); 1190 return; 1191 1192 -- When the type is frozen, it is legitimate to define a new 1193 -- non-primitive operation. 1194 1195 else 1196 return; 1197 end if; 1198 1199 -- Now, we are sure that the scope is a package spec. If the subprogram 1200 -- is declared after the freezing point of the type that's an error 1201 1202 elsif Is_Frozen (Tagged_Type) and then not Has_Dispatching_Parent then 1203 Error_Msg_N ("this primitive operation is declared too late", Subp); 1204 Error_Msg_NE 1205 ("??no primitive operations for& after this line", 1206 Freeze_Node (Tagged_Type), 1207 Tagged_Type); 1208 return; 1209 end if; 1210 1211 Check_Controlling_Formals (Tagged_Type, Subp); 1212 1213 Ovr_Subp := Old_Subp; 1214 1215 -- [Ada 2012:AI-0125]: Search for inherited hidden primitive that may be 1216 -- overridden by Subp. This only applies to source subprograms, and 1217 -- their declaration must carry an explicit overriding indicator. 1218 1219 if No (Ovr_Subp) 1220 and then Ada_Version >= Ada_2012 1221 and then Comes_From_Source (Subp) 1222 and then 1223 Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration 1224 then 1225 Ovr_Subp := Find_Hidden_Overridden_Primitive (Subp); 1226 1227 -- Verify that the proper overriding indicator has been supplied. 1228 1229 if Present (Ovr_Subp) 1230 and then 1231 not Must_Override (Specification (Unit_Declaration_Node (Subp))) 1232 then 1233 Error_Msg_NE ("missing overriding indicator for&", Subp, Subp); 1234 end if; 1235 end if; 1236 1237 -- Now it should be a correct primitive operation, put it in the list 1238 1239 if Present (Ovr_Subp) then 1240 1241 -- If the type has interfaces we complete this check after we set 1242 -- attribute Is_Dispatching_Operation. 1243 1244 Check_Subtype_Conformant (Subp, Ovr_Subp); 1245 1246 -- A primitive operation with the name of a primitive controlled 1247 -- operation does not override a non-visible overriding controlled 1248 -- operation, i.e. one declared in a private part when the full 1249 -- view of a type is controlled. Conversely, it will override a 1250 -- visible operation that may be declared in a partial view when 1251 -- the full view is controlled. 1252 1253 if Nam_In (Chars (Subp), Name_Initialize, Name_Adjust, Name_Finalize) 1254 and then Is_Controlled (Tagged_Type) 1255 and then not Is_Visibly_Controlled (Tagged_Type) 1256 and then not Is_Inherited_Public_Operation (Ovr_Subp) 1257 then 1258 Set_Overridden_Operation (Subp, Empty); 1259 1260 -- If the subprogram specification carries an overriding 1261 -- indicator, no need for the warning: it is either redundant, 1262 -- or else an error will be reported. 1263 1264 if Nkind (Parent (Subp)) = N_Procedure_Specification 1265 and then 1266 (Must_Override (Parent (Subp)) 1267 or else Must_Not_Override (Parent (Subp))) 1268 then 1269 null; 1270 1271 -- Here we need the warning 1272 1273 else 1274 Error_Msg_NE 1275 ("operation does not override inherited&??", Subp, Subp); 1276 end if; 1277 1278 else 1279 Override_Dispatching_Operation (Tagged_Type, Ovr_Subp, Subp); 1280 1281 -- Ada 2005 (AI-251): In case of late overriding of a primitive 1282 -- that covers abstract interface subprograms we must register it 1283 -- in all the secondary dispatch tables associated with abstract 1284 -- interfaces. We do this now only if not building static tables, 1285 -- nor when the expander is inactive (we avoid trying to register 1286 -- primitives in semantics-only mode, since the type may not have 1287 -- an associated dispatch table). Otherwise the patch code is 1288 -- emitted after those tables are built, to prevent access before 1289 -- elaboration in gigi. 1290 1291 if Body_Is_Last_Primitive and then Expander_Active then 1292 declare 1293 Subp_Body : constant Node_Id := Unit_Declaration_Node (Subp); 1294 Elmt : Elmt_Id; 1295 Prim : Node_Id; 1296 1297 begin 1298 Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); 1299 while Present (Elmt) loop 1300 Prim := Node (Elmt); 1301 1302 -- No code required to register primitives in VM targets 1303 1304 if Present (Alias (Prim)) 1305 and then Present (Interface_Alias (Prim)) 1306 and then Alias (Prim) = Subp 1307 and then not Building_Static_DT (Tagged_Type) 1308 and then VM_Target = No_VM 1309 then 1310 Insert_Actions_After (Subp_Body, 1311 Register_Primitive (Sloc (Subp_Body), Prim => Prim)); 1312 end if; 1313 1314 Next_Elmt (Elmt); 1315 end loop; 1316 1317 -- Redisplay the contents of the updated dispatch table 1318 1319 if Debug_Flag_ZZ then 1320 Write_Str ("Late overriding: "); 1321 Write_DT (Tagged_Type); 1322 end if; 1323 end; 1324 end if; 1325 end if; 1326 1327 -- If the tagged type is a concurrent type then we must be compiling 1328 -- with no code generation (we are either compiling a generic unit or 1329 -- compiling under -gnatc mode) because we have previously tested that 1330 -- no serious errors has been reported. In this case we do not add the 1331 -- primitive to the list of primitives of Tagged_Type but we leave the 1332 -- primitive decorated as a dispatching operation to be able to analyze 1333 -- and report errors associated with the Object.Operation notation. 1334 1335 elsif Is_Concurrent_Type (Tagged_Type) then 1336 pragma Assert (not Expander_Active); 1337 null; 1338 1339 -- If no old subprogram, then we add this as a dispatching operation, 1340 -- but we avoid doing this if an error was posted, to prevent annoying 1341 -- cascaded errors. 1342 1343 elsif not Error_Posted (Subp) then 1344 Add_Dispatching_Operation (Tagged_Type, Subp); 1345 end if; 1346 1347 Set_Is_Dispatching_Operation (Subp, True); 1348 1349 -- Ada 2005 (AI-251): If the type implements interfaces we must check 1350 -- subtype conformance against all the interfaces covered by this 1351 -- primitive. 1352 1353 if Present (Ovr_Subp) 1354 and then Has_Interfaces (Tagged_Type) 1355 then 1356 declare 1357 Ifaces_List : Elist_Id; 1358 Iface_Elmt : Elmt_Id; 1359 Iface_Prim_Elmt : Elmt_Id; 1360 Iface_Prim : Entity_Id; 1361 Ret_Typ : Entity_Id; 1362 1363 begin 1364 Collect_Interfaces (Tagged_Type, Ifaces_List); 1365 1366 Iface_Elmt := First_Elmt (Ifaces_List); 1367 while Present (Iface_Elmt) loop 1368 if not Is_Ancestor (Node (Iface_Elmt), Tagged_Type) then 1369 Iface_Prim_Elmt := 1370 First_Elmt (Primitive_Operations (Node (Iface_Elmt))); 1371 while Present (Iface_Prim_Elmt) loop 1372 Iface_Prim := Node (Iface_Prim_Elmt); 1373 1374 if Is_Interface_Conformant 1375 (Tagged_Type, Iface_Prim, Subp) 1376 then 1377 -- Handle procedures, functions whose return type 1378 -- matches, or functions not returning interfaces 1379 1380 if Ekind (Subp) = E_Procedure 1381 or else Etype (Iface_Prim) = Etype (Subp) 1382 or else not Is_Interface (Etype (Iface_Prim)) 1383 then 1384 Check_Subtype_Conformant 1385 (New_Id => Subp, 1386 Old_Id => Iface_Prim, 1387 Err_Loc => Subp, 1388 Skip_Controlling_Formals => True); 1389 1390 -- Handle functions returning interfaces 1391 1392 elsif Implements_Interface 1393 (Etype (Subp), Etype (Iface_Prim)) 1394 then 1395 -- Temporarily force both entities to return the 1396 -- same type. Required because Subtype_Conformant 1397 -- does not handle this case. 1398 1399 Ret_Typ := Etype (Iface_Prim); 1400 Set_Etype (Iface_Prim, Etype (Subp)); 1401 1402 Check_Subtype_Conformant 1403 (New_Id => Subp, 1404 Old_Id => Iface_Prim, 1405 Err_Loc => Subp, 1406 Skip_Controlling_Formals => True); 1407 1408 Set_Etype (Iface_Prim, Ret_Typ); 1409 end if; 1410 end if; 1411 1412 Next_Elmt (Iface_Prim_Elmt); 1413 end loop; 1414 end if; 1415 1416 Next_Elmt (Iface_Elmt); 1417 end loop; 1418 end; 1419 end if; 1420 1421 if not Body_Is_Last_Primitive then 1422 Set_DT_Position_Value (Subp, No_Uint); 1423 1424 elsif Has_Controlled_Component (Tagged_Type) 1425 and then Nam_In (Chars (Subp), Name_Initialize, 1426 Name_Adjust, 1427 Name_Finalize, 1428 Name_Finalize_Address) 1429 then 1430 declare 1431 F_Node : constant Node_Id := Freeze_Node (Tagged_Type); 1432 Decl : Node_Id; 1433 Old_P : Entity_Id; 1434 Old_Bod : Node_Id; 1435 Old_Spec : Entity_Id; 1436 1437 C_Names : constant array (1 .. 4) of Name_Id := 1438 (Name_Initialize, 1439 Name_Adjust, 1440 Name_Finalize, 1441 Name_Finalize_Address); 1442 1443 D_Names : constant array (1 .. 4) of TSS_Name_Type := 1444 (TSS_Deep_Initialize, 1445 TSS_Deep_Adjust, 1446 TSS_Deep_Finalize, 1447 TSS_Finalize_Address); 1448 1449 begin 1450 -- Remove previous controlled function which was constructed and 1451 -- analyzed when the type was frozen. This requires removing the 1452 -- body of the redefined primitive, as well as its specification 1453 -- if needed (there is no spec created for Deep_Initialize, see 1454 -- exp_ch3.adb). We must also dismantle the exception information 1455 -- that may have been generated for it when front end zero-cost 1456 -- tables are enabled. 1457 1458 for J in D_Names'Range loop 1459 Old_P := TSS (Tagged_Type, D_Names (J)); 1460 1461 if Present (Old_P) 1462 and then Chars (Subp) = C_Names (J) 1463 then 1464 Old_Bod := Unit_Declaration_Node (Old_P); 1465 Remove (Old_Bod); 1466 Set_Is_Eliminated (Old_P); 1467 Set_Scope (Old_P, Scope (Current_Scope)); 1468 1469 if Nkind (Old_Bod) = N_Subprogram_Body 1470 and then Present (Corresponding_Spec (Old_Bod)) 1471 then 1472 Old_Spec := Corresponding_Spec (Old_Bod); 1473 Set_Has_Completion (Old_Spec, False); 1474 end if; 1475 end if; 1476 end loop; 1477 1478 Build_Late_Proc (Tagged_Type, Chars (Subp)); 1479 1480 -- The new operation is added to the actions of the freeze node 1481 -- for the type, but this node has already been analyzed, so we 1482 -- must retrieve and analyze explicitly the new body. 1483 1484 if Present (F_Node) 1485 and then Present (Actions (F_Node)) 1486 then 1487 Decl := Last (Actions (F_Node)); 1488 Analyze (Decl); 1489 end if; 1490 end; 1491 end if; 1492 end Check_Dispatching_Operation; 1493 1494 ------------------------------------------ 1495 -- Check_Operation_From_Incomplete_Type -- 1496 ------------------------------------------ 1497 1498 procedure Check_Operation_From_Incomplete_Type 1499 (Subp : Entity_Id; 1500 Typ : Entity_Id) 1501 is 1502 Full : constant Entity_Id := Full_View (Typ); 1503 Parent_Typ : constant Entity_Id := Etype (Full); 1504 Old_Prim : constant Elist_Id := Primitive_Operations (Parent_Typ); 1505 New_Prim : constant Elist_Id := Primitive_Operations (Full); 1506 Op1, Op2 : Elmt_Id; 1507 Prev : Elmt_Id := No_Elmt; 1508 1509 function Derives_From (Parent_Subp : Entity_Id) return Boolean; 1510 -- Check that Subp has profile of an operation derived from Parent_Subp. 1511 -- Subp must have a parameter or result type that is Typ or an access 1512 -- parameter or access result type that designates Typ. 1513 1514 ------------------ 1515 -- Derives_From -- 1516 ------------------ 1517 1518 function Derives_From (Parent_Subp : Entity_Id) return Boolean is 1519 F1, F2 : Entity_Id; 1520 1521 begin 1522 if Chars (Parent_Subp) /= Chars (Subp) then 1523 return False; 1524 end if; 1525 1526 -- Check that the type of controlling formals is derived from the 1527 -- parent subprogram's controlling formal type (or designated type 1528 -- if the formal type is an anonymous access type). 1529 1530 F1 := First_Formal (Parent_Subp); 1531 F2 := First_Formal (Subp); 1532 while Present (F1) and then Present (F2) loop 1533 if Ekind (Etype (F1)) = E_Anonymous_Access_Type then 1534 if Ekind (Etype (F2)) /= E_Anonymous_Access_Type then 1535 return False; 1536 elsif Designated_Type (Etype (F1)) = Parent_Typ 1537 and then Designated_Type (Etype (F2)) /= Full 1538 then 1539 return False; 1540 end if; 1541 1542 elsif Ekind (Etype (F2)) = E_Anonymous_Access_Type then 1543 return False; 1544 1545 elsif Etype (F1) = Parent_Typ and then Etype (F2) /= Full then 1546 return False; 1547 end if; 1548 1549 Next_Formal (F1); 1550 Next_Formal (F2); 1551 end loop; 1552 1553 -- Check that a controlling result type is derived from the parent 1554 -- subprogram's result type (or designated type if the result type 1555 -- is an anonymous access type). 1556 1557 if Ekind (Parent_Subp) = E_Function then 1558 if Ekind (Subp) /= E_Function then 1559 return False; 1560 1561 elsif Ekind (Etype (Parent_Subp)) = E_Anonymous_Access_Type then 1562 if Ekind (Etype (Subp)) /= E_Anonymous_Access_Type then 1563 return False; 1564 1565 elsif Designated_Type (Etype (Parent_Subp)) = Parent_Typ 1566 and then Designated_Type (Etype (Subp)) /= Full 1567 then 1568 return False; 1569 end if; 1570 1571 elsif Ekind (Etype (Subp)) = E_Anonymous_Access_Type then 1572 return False; 1573 1574 elsif Etype (Parent_Subp) = Parent_Typ 1575 and then Etype (Subp) /= Full 1576 then 1577 return False; 1578 end if; 1579 1580 elsif Ekind (Subp) = E_Function then 1581 return False; 1582 end if; 1583 1584 return No (F1) and then No (F2); 1585 end Derives_From; 1586 1587 -- Start of processing for Check_Operation_From_Incomplete_Type 1588 1589 begin 1590 -- The operation may override an inherited one, or may be a new one 1591 -- altogether. The inherited operation will have been hidden by the 1592 -- current one at the point of the type derivation, so it does not 1593 -- appear in the list of primitive operations of the type. We have to 1594 -- find the proper place of insertion in the list of primitive opera- 1595 -- tions by iterating over the list for the parent type. 1596 1597 Op1 := First_Elmt (Old_Prim); 1598 Op2 := First_Elmt (New_Prim); 1599 while Present (Op1) and then Present (Op2) loop 1600 if Derives_From (Node (Op1)) then 1601 if No (Prev) then 1602 1603 -- Avoid adding it to the list of primitives if already there 1604 1605 if Node (Op2) /= Subp then 1606 Prepend_Elmt (Subp, New_Prim); 1607 end if; 1608 1609 else 1610 Insert_Elmt_After (Subp, Prev); 1611 end if; 1612 1613 return; 1614 end if; 1615 1616 Prev := Op2; 1617 Next_Elmt (Op1); 1618 Next_Elmt (Op2); 1619 end loop; 1620 1621 -- Operation is a new primitive 1622 1623 Append_Elmt (Subp, New_Prim); 1624 end Check_Operation_From_Incomplete_Type; 1625 1626 --------------------------------------- 1627 -- Check_Operation_From_Private_View -- 1628 --------------------------------------- 1629 1630 procedure Check_Operation_From_Private_View (Subp, Old_Subp : Entity_Id) is 1631 Tagged_Type : Entity_Id; 1632 1633 begin 1634 if Is_Dispatching_Operation (Alias (Subp)) then 1635 Set_Scope (Subp, Current_Scope); 1636 Tagged_Type := Find_Dispatching_Type (Subp); 1637 1638 -- Add Old_Subp to primitive operations if not already present 1639 1640 if Present (Tagged_Type) and then Is_Tagged_Type (Tagged_Type) then 1641 Append_Unique_Elmt (Old_Subp, Primitive_Operations (Tagged_Type)); 1642 1643 -- If Old_Subp isn't already marked as dispatching then this is 1644 -- the case of an operation of an untagged private type fulfilled 1645 -- by a tagged type that overrides an inherited dispatching 1646 -- operation, so we set the necessary dispatching attributes here. 1647 1648 if not Is_Dispatching_Operation (Old_Subp) then 1649 1650 -- If the untagged type has no discriminants, and the full 1651 -- view is constrained, there will be a spurious mismatch of 1652 -- subtypes on the controlling arguments, because the tagged 1653 -- type is the internal base type introduced in the derivation. 1654 -- Use the original type to verify conformance, rather than the 1655 -- base type. 1656 1657 if not Comes_From_Source (Tagged_Type) 1658 and then Has_Discriminants (Tagged_Type) 1659 then 1660 declare 1661 Formal : Entity_Id; 1662 1663 begin 1664 Formal := First_Formal (Old_Subp); 1665 while Present (Formal) loop 1666 if Tagged_Type = Base_Type (Etype (Formal)) then 1667 Tagged_Type := Etype (Formal); 1668 end if; 1669 1670 Next_Formal (Formal); 1671 end loop; 1672 end; 1673 1674 if Tagged_Type = Base_Type (Etype (Old_Subp)) then 1675 Tagged_Type := Etype (Old_Subp); 1676 end if; 1677 end if; 1678 1679 Check_Controlling_Formals (Tagged_Type, Old_Subp); 1680 Set_Is_Dispatching_Operation (Old_Subp, True); 1681 Set_DT_Position_Value (Old_Subp, No_Uint); 1682 end if; 1683 1684 -- If the old subprogram is an explicit renaming of some other 1685 -- entity, it is not overridden by the inherited subprogram. 1686 -- Otherwise, update its alias and other attributes. 1687 1688 if Present (Alias (Old_Subp)) 1689 and then Nkind (Unit_Declaration_Node (Old_Subp)) /= 1690 N_Subprogram_Renaming_Declaration 1691 then 1692 Set_Alias (Old_Subp, Alias (Subp)); 1693 1694 -- The derived subprogram should inherit the abstractness of 1695 -- the parent subprogram (except in the case of a function 1696 -- returning the type). This sets the abstractness properly 1697 -- for cases where a private extension may have inherited an 1698 -- abstract operation, but the full type is derived from a 1699 -- descendant type and inherits a nonabstract version. 1700 1701 if Etype (Subp) /= Tagged_Type then 1702 Set_Is_Abstract_Subprogram 1703 (Old_Subp, Is_Abstract_Subprogram (Alias (Subp))); 1704 end if; 1705 end if; 1706 end if; 1707 end if; 1708 end Check_Operation_From_Private_View; 1709 1710 -------------------------- 1711 -- Find_Controlling_Arg -- 1712 -------------------------- 1713 1714 function Find_Controlling_Arg (N : Node_Id) return Node_Id is 1715 Orig_Node : constant Node_Id := Original_Node (N); 1716 Typ : Entity_Id; 1717 1718 begin 1719 if Nkind (Orig_Node) = N_Qualified_Expression then 1720 return Find_Controlling_Arg (Expression (Orig_Node)); 1721 end if; 1722 1723 -- Dispatching on result case. If expansion is disabled, the node still 1724 -- has the structure of a function call. However, if the function name 1725 -- is an operator and the call was given in infix form, the original 1726 -- node has no controlling result and we must examine the current node. 1727 1728 if Nkind (N) = N_Function_Call 1729 and then Present (Controlling_Argument (N)) 1730 and then Has_Controlling_Result (Entity (Name (N))) 1731 then 1732 return Controlling_Argument (N); 1733 1734 -- If expansion is enabled, the call may have been transformed into 1735 -- an indirect call, and we need to recover the original node. 1736 1737 elsif Nkind (Orig_Node) = N_Function_Call 1738 and then Present (Controlling_Argument (Orig_Node)) 1739 and then Has_Controlling_Result (Entity (Name (Orig_Node))) 1740 then 1741 return Controlling_Argument (Orig_Node); 1742 1743 -- Type conversions are dynamically tagged if the target type, or its 1744 -- designated type, are classwide. An interface conversion expands into 1745 -- a dereference, so test must be performed on the original node. 1746 1747 elsif Nkind (Orig_Node) = N_Type_Conversion 1748 and then Nkind (N) = N_Explicit_Dereference 1749 and then Is_Controlling_Actual (N) 1750 then 1751 declare 1752 Target_Type : constant Entity_Id := 1753 Entity (Subtype_Mark (Orig_Node)); 1754 1755 begin 1756 if Is_Class_Wide_Type (Target_Type) then 1757 return N; 1758 1759 elsif Is_Access_Type (Target_Type) 1760 and then Is_Class_Wide_Type (Designated_Type (Target_Type)) 1761 then 1762 return N; 1763 1764 else 1765 return Empty; 1766 end if; 1767 end; 1768 1769 -- Normal case 1770 1771 elsif Is_Controlling_Actual (N) 1772 or else 1773 (Nkind (Parent (N)) = N_Qualified_Expression 1774 and then Is_Controlling_Actual (Parent (N))) 1775 then 1776 Typ := Etype (N); 1777 1778 if Is_Access_Type (Typ) then 1779 1780 -- In the case of an Access attribute, use the type of the prefix, 1781 -- since in the case of an actual for an access parameter, the 1782 -- attribute's type may be of a specific designated type, even 1783 -- though the prefix type is class-wide. 1784 1785 if Nkind (N) = N_Attribute_Reference then 1786 Typ := Etype (Prefix (N)); 1787 1788 -- An allocator is dispatching if the type of qualified expression 1789 -- is class_wide, in which case this is the controlling type. 1790 1791 elsif Nkind (Orig_Node) = N_Allocator 1792 and then Nkind (Expression (Orig_Node)) = N_Qualified_Expression 1793 then 1794 Typ := Etype (Expression (Orig_Node)); 1795 else 1796 Typ := Designated_Type (Typ); 1797 end if; 1798 end if; 1799 1800 if Is_Class_Wide_Type (Typ) 1801 or else 1802 (Nkind (Parent (N)) = N_Qualified_Expression 1803 and then Is_Access_Type (Etype (N)) 1804 and then Is_Class_Wide_Type (Designated_Type (Etype (N)))) 1805 then 1806 return N; 1807 end if; 1808 end if; 1809 1810 return Empty; 1811 end Find_Controlling_Arg; 1812 1813 --------------------------- 1814 -- Find_Dispatching_Type -- 1815 --------------------------- 1816 1817 function Find_Dispatching_Type (Subp : Entity_Id) return Entity_Id is 1818 A_Formal : Entity_Id; 1819 Formal : Entity_Id; 1820 Ctrl_Type : Entity_Id; 1821 1822 begin 1823 if Ekind_In (Subp, E_Function, E_Procedure) 1824 and then Present (DTC_Entity (Subp)) 1825 then 1826 return Scope (DTC_Entity (Subp)); 1827 1828 -- For subprograms internally generated by derivations of tagged types 1829 -- use the alias subprogram as a reference to locate the dispatching 1830 -- type of Subp. 1831 1832 elsif not Comes_From_Source (Subp) 1833 and then Present (Alias (Subp)) 1834 and then Is_Dispatching_Operation (Alias (Subp)) 1835 then 1836 if Ekind (Alias (Subp)) = E_Function 1837 and then Has_Controlling_Result (Alias (Subp)) 1838 then 1839 return Check_Controlling_Type (Etype (Subp), Subp); 1840 1841 else 1842 Formal := First_Formal (Subp); 1843 A_Formal := First_Formal (Alias (Subp)); 1844 while Present (A_Formal) loop 1845 if Is_Controlling_Formal (A_Formal) then 1846 return Check_Controlling_Type (Etype (Formal), Subp); 1847 end if; 1848 1849 Next_Formal (Formal); 1850 Next_Formal (A_Formal); 1851 end loop; 1852 1853 pragma Assert (False); 1854 return Empty; 1855 end if; 1856 1857 -- General case 1858 1859 else 1860 Formal := First_Formal (Subp); 1861 while Present (Formal) loop 1862 Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); 1863 1864 if Present (Ctrl_Type) then 1865 return Ctrl_Type; 1866 end if; 1867 1868 Next_Formal (Formal); 1869 end loop; 1870 1871 -- The subprogram may also be dispatching on result 1872 1873 if Present (Etype (Subp)) then 1874 return Check_Controlling_Type (Etype (Subp), Subp); 1875 end if; 1876 end if; 1877 1878 pragma Assert (not Is_Dispatching_Operation (Subp)); 1879 return Empty; 1880 end Find_Dispatching_Type; 1881 1882 -------------------------------------- 1883 -- Find_Hidden_Overridden_Primitive -- 1884 -------------------------------------- 1885 1886 function Find_Hidden_Overridden_Primitive (S : Entity_Id) return Entity_Id 1887 is 1888 Tag_Typ : constant Entity_Id := Find_Dispatching_Type (S); 1889 Elmt : Elmt_Id; 1890 Orig_Prim : Entity_Id; 1891 Prim : Entity_Id; 1892 Vis_List : Elist_Id; 1893 1894 begin 1895 -- This Ada 2012 rule applies only for type extensions or private 1896 -- extensions, where the parent type is not in a parent unit, and 1897 -- where an operation is never declared but still inherited. 1898 1899 if No (Tag_Typ) 1900 or else not Is_Record_Type (Tag_Typ) 1901 or else Etype (Tag_Typ) = Tag_Typ 1902 or else In_Open_Scopes (Scope (Etype (Tag_Typ))) 1903 then 1904 return Empty; 1905 end if; 1906 1907 -- Collect the list of visible ancestor of the tagged type 1908 1909 Vis_List := Visible_Ancestors (Tag_Typ); 1910 1911 Elmt := First_Elmt (Primitive_Operations (Tag_Typ)); 1912 while Present (Elmt) loop 1913 Prim := Node (Elmt); 1914 1915 -- Find an inherited hidden dispatching primitive with the name of S 1916 -- and a type-conformant profile. 1917 1918 if Present (Alias (Prim)) 1919 and then Is_Hidden (Alias (Prim)) 1920 and then Find_Dispatching_Type (Alias (Prim)) /= Tag_Typ 1921 and then Primitive_Names_Match (S, Prim) 1922 and then Type_Conformant (S, Prim) 1923 then 1924 declare 1925 Vis_Ancestor : Elmt_Id; 1926 Elmt : Elmt_Id; 1927 1928 begin 1929 -- The original corresponding operation of Prim must be an 1930 -- operation of a visible ancestor of the dispatching type S, 1931 -- and the original corresponding operation of S2 must be 1932 -- visible. 1933 1934 Orig_Prim := Original_Corresponding_Operation (Prim); 1935 1936 if Orig_Prim /= Prim 1937 and then Is_Immediately_Visible (Orig_Prim) 1938 then 1939 Vis_Ancestor := First_Elmt (Vis_List); 1940 while Present (Vis_Ancestor) loop 1941 Elmt := 1942 First_Elmt (Primitive_Operations (Node (Vis_Ancestor))); 1943 while Present (Elmt) loop 1944 if Node (Elmt) = Orig_Prim then 1945 Set_Overridden_Operation (S, Prim); 1946 Set_Alias (Prim, Orig_Prim); 1947 return Prim; 1948 end if; 1949 1950 Next_Elmt (Elmt); 1951 end loop; 1952 1953 Next_Elmt (Vis_Ancestor); 1954 end loop; 1955 end if; 1956 end; 1957 end if; 1958 1959 Next_Elmt (Elmt); 1960 end loop; 1961 1962 return Empty; 1963 end Find_Hidden_Overridden_Primitive; 1964 1965 --------------------------------------- 1966 -- Find_Primitive_Covering_Interface -- 1967 --------------------------------------- 1968 1969 function Find_Primitive_Covering_Interface 1970 (Tagged_Type : Entity_Id; 1971 Iface_Prim : Entity_Id) return Entity_Id 1972 is 1973 E : Entity_Id; 1974 El : Elmt_Id; 1975 1976 begin 1977 pragma Assert (Is_Interface (Find_Dispatching_Type (Iface_Prim)) 1978 or else (Present (Alias (Iface_Prim)) 1979 and then 1980 Is_Interface 1981 (Find_Dispatching_Type (Ultimate_Alias (Iface_Prim))))); 1982 1983 -- Search in the homonym chain. Done to speed up locating visible 1984 -- entities and required to catch primitives associated with the partial 1985 -- view of private types when processing the corresponding full view. 1986 1987 E := Current_Entity (Iface_Prim); 1988 while Present (E) loop 1989 if Is_Subprogram (E) 1990 and then Is_Dispatching_Operation (E) 1991 and then Is_Interface_Conformant (Tagged_Type, Iface_Prim, E) 1992 then 1993 return E; 1994 end if; 1995 1996 E := Homonym (E); 1997 end loop; 1998 1999 -- Search in the list of primitives of the type. Required to locate 2000 -- the covering primitive if the covering primitive is not visible 2001 -- (for example, non-visible inherited primitive of private type). 2002 2003 El := First_Elmt (Primitive_Operations (Tagged_Type)); 2004 while Present (El) loop 2005 E := Node (El); 2006 2007 -- Keep separate the management of internal entities that link 2008 -- primitives with interface primitives from tagged type primitives. 2009 2010 if No (Interface_Alias (E)) then 2011 if Present (Alias (E)) then 2012 2013 -- This interface primitive has not been covered yet 2014 2015 if Alias (E) = Iface_Prim then 2016 return E; 2017 2018 -- The covering primitive was inherited 2019 2020 elsif Overridden_Operation (Ultimate_Alias (E)) 2021 = Iface_Prim 2022 then 2023 return E; 2024 end if; 2025 end if; 2026 2027 -- Check if E covers the interface primitive (includes case in 2028 -- which E is an inherited private primitive). 2029 2030 if Is_Interface_Conformant (Tagged_Type, Iface_Prim, E) then 2031 return E; 2032 end if; 2033 2034 -- Use the internal entity that links the interface primitive with 2035 -- the covering primitive to locate the entity. 2036 2037 elsif Interface_Alias (E) = Iface_Prim then 2038 return Alias (E); 2039 end if; 2040 2041 Next_Elmt (El); 2042 end loop; 2043 2044 -- Not found 2045 2046 return Empty; 2047 end Find_Primitive_Covering_Interface; 2048 2049 --------------------------- 2050 -- Inherited_Subprograms -- 2051 --------------------------- 2052 2053 function Inherited_Subprograms 2054 (S : Entity_Id; 2055 No_Interfaces : Boolean := False; 2056 Interfaces_Only : Boolean := False) return Subprogram_List 2057 is 2058 Result : Subprogram_List (1 .. 6000); 2059 -- 6000 here is intended to be infinity. We could use an expandable 2060 -- table, but it would be awfully heavy, and there is no way that we 2061 -- could reasonably exceed this value. 2062 2063 N : Int := 0; 2064 -- Number of entries in Result 2065 2066 Parent_Op : Entity_Id; 2067 -- Traverses the Overridden_Operation chain 2068 2069 procedure Store_IS (E : Entity_Id); 2070 -- Stores E in Result if not already stored 2071 2072 -------------- 2073 -- Store_IS -- 2074 -------------- 2075 2076 procedure Store_IS (E : Entity_Id) is 2077 begin 2078 for J in 1 .. N loop 2079 if E = Result (J) then 2080 return; 2081 end if; 2082 end loop; 2083 2084 N := N + 1; 2085 Result (N) := E; 2086 end Store_IS; 2087 2088 -- Start of processing for Inherited_Subprograms 2089 2090 begin 2091 pragma Assert (not (No_Interfaces and Interfaces_Only)); 2092 2093 if Present (S) and then Is_Dispatching_Operation (S) then 2094 2095 -- Deal with direct inheritance 2096 2097 if not Interfaces_Only then 2098 Parent_Op := S; 2099 loop 2100 Parent_Op := Overridden_Operation (Parent_Op); 2101 exit when No (Parent_Op) 2102 or else 2103 (No_Interfaces 2104 and then 2105 Is_Interface (Find_Dispatching_Type (Parent_Op))); 2106 2107 if Is_Subprogram_Or_Generic_Subprogram (Parent_Op) then 2108 Store_IS (Parent_Op); 2109 end if; 2110 end loop; 2111 end if; 2112 2113 -- Now deal with interfaces 2114 2115 if not No_Interfaces then 2116 declare 2117 Tag_Typ : Entity_Id; 2118 Prim : Entity_Id; 2119 Elmt : Elmt_Id; 2120 2121 begin 2122 Tag_Typ := Find_Dispatching_Type (S); 2123 2124 if Is_Concurrent_Type (Tag_Typ) then 2125 Tag_Typ := Corresponding_Record_Type (Tag_Typ); 2126 end if; 2127 2128 -- Search primitive operations of dispatching type 2129 2130 if Present (Tag_Typ) 2131 and then Present (Primitive_Operations (Tag_Typ)) 2132 then 2133 Elmt := First_Elmt (Primitive_Operations (Tag_Typ)); 2134 while Present (Elmt) loop 2135 Prim := Node (Elmt); 2136 2137 -- The following test eliminates some odd cases in which 2138 -- Ekind (Prim) is Void, to be investigated further ??? 2139 2140 if not Is_Subprogram_Or_Generic_Subprogram (Prim) then 2141 null; 2142 2143 -- For [generic] subprogram, look at interface alias 2144 2145 elsif Present (Interface_Alias (Prim)) 2146 and then Alias (Prim) = S 2147 then 2148 -- We have found a primitive covered by S 2149 2150 Store_IS (Interface_Alias (Prim)); 2151 end if; 2152 2153 Next_Elmt (Elmt); 2154 end loop; 2155 end if; 2156 end; 2157 end if; 2158 end if; 2159 2160 return Result (1 .. N); 2161 end Inherited_Subprograms; 2162 2163 --------------------------- 2164 -- Is_Dynamically_Tagged -- 2165 --------------------------- 2166 2167 function Is_Dynamically_Tagged (N : Node_Id) return Boolean is 2168 begin 2169 if Nkind (N) = N_Error then 2170 return False; 2171 2172 elsif Present (Find_Controlling_Arg (N)) then 2173 return True; 2174 2175 -- Special cases: entities, and calls that dispatch on result 2176 2177 elsif Is_Entity_Name (N) then 2178 return Is_Class_Wide_Type (Etype (N)); 2179 2180 elsif Nkind (N) = N_Function_Call 2181 and then Is_Class_Wide_Type (Etype (N)) 2182 then 2183 return True; 2184 2185 -- Otherwise check whether call has controlling argument 2186 2187 else 2188 return False; 2189 end if; 2190 end Is_Dynamically_Tagged; 2191 2192 --------------------------------- 2193 -- Is_Null_Interface_Primitive -- 2194 --------------------------------- 2195 2196 function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean is 2197 begin 2198 return Comes_From_Source (E) 2199 and then Is_Dispatching_Operation (E) 2200 and then Ekind (E) = E_Procedure 2201 and then Null_Present (Parent (E)) 2202 and then Is_Interface (Find_Dispatching_Type (E)); 2203 end Is_Null_Interface_Primitive; 2204 2205 ----------------------------------- 2206 -- Is_Inherited_Public_Operation -- 2207 ----------------------------------- 2208 2209 function Is_Inherited_Public_Operation (Op : Entity_Id) return Boolean is 2210 Prim : constant Entity_Id := Alias (Op); 2211 Scop : constant Entity_Id := Scope (Prim); 2212 Pack_Decl : Node_Id; 2213 2214 begin 2215 if Comes_From_Source (Prim) and then Ekind (Scop) = E_Package then 2216 Pack_Decl := Unit_Declaration_Node (Scop); 2217 return Nkind (Pack_Decl) = N_Package_Declaration 2218 and then List_Containing (Unit_Declaration_Node (Prim)) = 2219 Visible_Declarations (Specification (Pack_Decl)); 2220 2221 else 2222 return False; 2223 end if; 2224 end Is_Inherited_Public_Operation; 2225 2226 -------------------------- 2227 -- Is_Tag_Indeterminate -- 2228 -------------------------- 2229 2230 function Is_Tag_Indeterminate (N : Node_Id) return Boolean is 2231 Nam : Entity_Id; 2232 Actual : Node_Id; 2233 Orig_Node : constant Node_Id := Original_Node (N); 2234 2235 begin 2236 if Nkind (Orig_Node) = N_Function_Call 2237 and then Is_Entity_Name (Name (Orig_Node)) 2238 then 2239 Nam := Entity (Name (Orig_Node)); 2240 2241 if not Has_Controlling_Result (Nam) then 2242 return False; 2243 2244 -- The function may have a controlling result, but if the return type 2245 -- is not visibly tagged, then this is not tag-indeterminate. 2246 2247 elsif Is_Access_Type (Etype (Nam)) 2248 and then not Is_Tagged_Type (Designated_Type (Etype (Nam))) 2249 then 2250 return False; 2251 2252 -- An explicit dereference means that the call has already been 2253 -- expanded and there is no tag to propagate. 2254 2255 elsif Nkind (N) = N_Explicit_Dereference then 2256 return False; 2257 2258 -- If there are no actuals, the call is tag-indeterminate 2259 2260 elsif No (Parameter_Associations (Orig_Node)) then 2261 return True; 2262 2263 else 2264 Actual := First_Actual (Orig_Node); 2265 while Present (Actual) loop 2266 if Is_Controlling_Actual (Actual) 2267 and then not Is_Tag_Indeterminate (Actual) 2268 then 2269 -- One operand is dispatching 2270 2271 return False; 2272 end if; 2273 2274 Next_Actual (Actual); 2275 end loop; 2276 2277 return True; 2278 end if; 2279 2280 elsif Nkind (Orig_Node) = N_Qualified_Expression then 2281 return Is_Tag_Indeterminate (Expression (Orig_Node)); 2282 2283 -- Case of a call to the Input attribute (possibly rewritten), which is 2284 -- always tag-indeterminate except when its prefix is a Class attribute. 2285 2286 elsif Nkind (Orig_Node) = N_Attribute_Reference 2287 and then 2288 Get_Attribute_Id (Attribute_Name (Orig_Node)) = Attribute_Input 2289 and then Nkind (Prefix (Orig_Node)) /= N_Attribute_Reference 2290 then 2291 return True; 2292 2293 -- In Ada 2005, a function that returns an anonymous access type can be 2294 -- dispatching, and the dereference of a call to such a function can 2295 -- also be tag-indeterminate if the call itself is. 2296 2297 elsif Nkind (Orig_Node) = N_Explicit_Dereference 2298 and then Ada_Version >= Ada_2005 2299 then 2300 return Is_Tag_Indeterminate (Prefix (Orig_Node)); 2301 2302 else 2303 return False; 2304 end if; 2305 end Is_Tag_Indeterminate; 2306 2307 ------------------------------------ 2308 -- Override_Dispatching_Operation -- 2309 ------------------------------------ 2310 2311 procedure Override_Dispatching_Operation 2312 (Tagged_Type : Entity_Id; 2313 Prev_Op : Entity_Id; 2314 New_Op : Entity_Id; 2315 Is_Wrapper : Boolean := False) 2316 is 2317 Elmt : Elmt_Id; 2318 Prim : Node_Id; 2319 2320 begin 2321 -- Diagnose failure to match No_Return in parent (Ada-2005, AI-414, but 2322 -- we do it unconditionally in Ada 95 now, since this is our pragma). 2323 2324 if No_Return (Prev_Op) and then not No_Return (New_Op) then 2325 Error_Msg_N ("procedure & must have No_Return pragma", New_Op); 2326 Error_Msg_N ("\since overridden procedure has No_Return", New_Op); 2327 end if; 2328 2329 -- If there is no previous operation to override, the type declaration 2330 -- was malformed, and an error must have been emitted already. 2331 2332 Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); 2333 while Present (Elmt) and then Node (Elmt) /= Prev_Op loop 2334 Next_Elmt (Elmt); 2335 end loop; 2336 2337 if No (Elmt) then 2338 return; 2339 end if; 2340 2341 -- The location of entities that come from source in the list of 2342 -- primitives of the tagged type must follow their order of occurrence 2343 -- in the sources to fulfill the C++ ABI. If the overridden entity is a 2344 -- primitive of an interface that is not implemented by the parents of 2345 -- this tagged type (that is, it is an alias of an interface primitive 2346 -- generated by Derive_Interface_Progenitors), then we must append the 2347 -- new entity at the end of the list of primitives. 2348 2349 if Present (Alias (Prev_Op)) 2350 and then Etype (Tagged_Type) /= Tagged_Type 2351 and then Is_Interface (Find_Dispatching_Type (Alias (Prev_Op))) 2352 and then not Is_Ancestor (Find_Dispatching_Type (Alias (Prev_Op)), 2353 Tagged_Type, Use_Full_View => True) 2354 and then not Implements_Interface 2355 (Etype (Tagged_Type), 2356 Find_Dispatching_Type (Alias (Prev_Op))) 2357 then 2358 Remove_Elmt (Primitive_Operations (Tagged_Type), Elmt); 2359 Append_Elmt (New_Op, Primitive_Operations (Tagged_Type)); 2360 2361 -- The new primitive replaces the overridden entity. Required to ensure 2362 -- that overriding primitive is assigned the same dispatch table slot. 2363 2364 else 2365 Replace_Elmt (Elmt, New_Op); 2366 end if; 2367 2368 if Ada_Version >= Ada_2005 and then Has_Interfaces (Tagged_Type) then 2369 2370 -- Ada 2005 (AI-251): Update the attribute alias of all the aliased 2371 -- entities of the overridden primitive to reference New_Op, and 2372 -- also propagate the proper value of Is_Abstract_Subprogram. Verify 2373 -- that the new operation is subtype conformant with the interface 2374 -- operations that it implements (for operations inherited from the 2375 -- parent itself, this check is made when building the derived type). 2376 2377 -- Note: This code is executed with internally generated wrappers of 2378 -- functions with controlling result and late overridings. 2379 2380 Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); 2381 while Present (Elmt) loop 2382 Prim := Node (Elmt); 2383 2384 if Prim = New_Op then 2385 null; 2386 2387 -- Note: The check on Is_Subprogram protects the frontend against 2388 -- reading attributes in entities that are not yet fully decorated 2389 2390 elsif Is_Subprogram (Prim) 2391 and then Present (Interface_Alias (Prim)) 2392 and then Alias (Prim) = Prev_Op 2393 then 2394 Set_Alias (Prim, New_Op); 2395 2396 -- No further decoration needed yet for internally generated 2397 -- wrappers of controlling functions since (at this stage) 2398 -- they are not yet decorated. 2399 2400 if not Is_Wrapper then 2401 Check_Subtype_Conformant (New_Op, Prim); 2402 2403 Set_Is_Abstract_Subprogram (Prim, 2404 Is_Abstract_Subprogram (New_Op)); 2405 2406 -- Ensure that this entity will be expanded to fill the 2407 -- corresponding entry in its dispatch table. 2408 2409 if not Is_Abstract_Subprogram (Prim) then 2410 Set_Has_Delayed_Freeze (Prim); 2411 end if; 2412 end if; 2413 end if; 2414 2415 Next_Elmt (Elmt); 2416 end loop; 2417 end if; 2418 2419 if (not Is_Package_Or_Generic_Package (Current_Scope)) 2420 or else not In_Private_Part (Current_Scope) 2421 then 2422 -- Not a private primitive 2423 2424 null; 2425 2426 else pragma Assert (Is_Inherited_Operation (Prev_Op)); 2427 2428 -- Make the overriding operation into an alias of the implicit one. 2429 -- In this fashion a call from outside ends up calling the new body 2430 -- even if non-dispatching, and a call from inside calls the over- 2431 -- riding operation because it hides the implicit one. To indicate 2432 -- that the body of Prev_Op is never called, set its dispatch table 2433 -- entity to Empty. If the overridden operation has a dispatching 2434 -- result, so does the overriding one. 2435 2436 Set_Alias (Prev_Op, New_Op); 2437 Set_DTC_Entity (Prev_Op, Empty); 2438 Set_Has_Controlling_Result (New_Op, Has_Controlling_Result (Prev_Op)); 2439 return; 2440 end if; 2441 end Override_Dispatching_Operation; 2442 2443 ------------------- 2444 -- Propagate_Tag -- 2445 ------------------- 2446 2447 procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id) is 2448 Call_Node : Node_Id; 2449 Arg : Node_Id; 2450 2451 begin 2452 if Nkind (Actual) = N_Function_Call then 2453 Call_Node := Actual; 2454 2455 elsif Nkind (Actual) = N_Identifier 2456 and then Nkind (Original_Node (Actual)) = N_Function_Call 2457 then 2458 -- Call rewritten as object declaration when stack-checking is 2459 -- enabled. Propagate tag to expression in declaration, which is 2460 -- original call. 2461 2462 Call_Node := Expression (Parent (Entity (Actual))); 2463 2464 -- Ada 2005: If this is a dereference of a call to a function with a 2465 -- dispatching access-result, the tag is propagated when the dereference 2466 -- itself is expanded (see exp_ch6.adb) and there is nothing else to do. 2467 2468 elsif Nkind (Actual) = N_Explicit_Dereference 2469 and then Nkind (Original_Node (Prefix (Actual))) = N_Function_Call 2470 then 2471 return; 2472 2473 -- When expansion is suppressed, an unexpanded call to 'Input can occur, 2474 -- and in that case we can simply return. 2475 2476 elsif Nkind (Actual) = N_Attribute_Reference then 2477 pragma Assert (Attribute_Name (Actual) = Name_Input); 2478 2479 return; 2480 2481 -- Only other possibilities are parenthesized or qualified expression, 2482 -- or an expander-generated unchecked conversion of a function call to 2483 -- a stream Input attribute. 2484 2485 else 2486 Call_Node := Expression (Actual); 2487 end if; 2488 2489 -- No action needed if the call has been already expanded 2490 2491 if Is_Expanded_Dispatching_Call (Call_Node) then 2492 return; 2493 end if; 2494 2495 -- Do not set the Controlling_Argument if already set. This happens in 2496 -- the special case of _Input (see Exp_Attr, case Input). 2497 2498 if No (Controlling_Argument (Call_Node)) then 2499 Set_Controlling_Argument (Call_Node, Control); 2500 end if; 2501 2502 Arg := First_Actual (Call_Node); 2503 while Present (Arg) loop 2504 if Is_Tag_Indeterminate (Arg) then 2505 Propagate_Tag (Control, Arg); 2506 end if; 2507 2508 Next_Actual (Arg); 2509 end loop; 2510 2511 -- Expansion of dispatching calls is suppressed when VM_Target, because 2512 -- the VM back-ends directly handle the generation of dispatching calls 2513 -- and would have to undo any expansion to an indirect call. 2514 2515 if Tagged_Type_Expansion then 2516 declare 2517 Call_Typ : constant Entity_Id := Etype (Call_Node); 2518 2519 begin 2520 Expand_Dispatching_Call (Call_Node); 2521 2522 -- If the controlling argument is an interface type and the type 2523 -- of Call_Node differs then we must add an implicit conversion to 2524 -- force displacement of the pointer to the object to reference 2525 -- the secondary dispatch table of the interface. 2526 2527 if Is_Interface (Etype (Control)) 2528 and then Etype (Control) /= Call_Typ 2529 then 2530 -- Cannot use Convert_To because the previous call to 2531 -- Expand_Dispatching_Call leaves decorated the Call_Node 2532 -- with the type of Control. 2533 2534 Rewrite (Call_Node, 2535 Make_Type_Conversion (Sloc (Call_Node), 2536 Subtype_Mark => 2537 New_Occurrence_Of (Etype (Control), Sloc (Call_Node)), 2538 Expression => Relocate_Node (Call_Node))); 2539 Set_Etype (Call_Node, Etype (Control)); 2540 Set_Analyzed (Call_Node); 2541 2542 Expand_Interface_Conversion (Call_Node); 2543 end if; 2544 end; 2545 2546 -- Expansion of a dispatching call results in an indirect call, which in 2547 -- turn causes current values to be killed (see Resolve_Call), so on VM 2548 -- targets we do the call here to ensure consistent warnings between VM 2549 -- and non-VM targets. 2550 2551 else 2552 Kill_Current_Values; 2553 end if; 2554 end Propagate_Tag; 2555 2556end Sem_Disp; 2557