1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- E X P A N D E R -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2018, 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 Debug_A; use Debug_A; 29with Exp_Aggr; use Exp_Aggr; 30with Exp_SPARK; use Exp_SPARK; 31with Exp_Attr; use Exp_Attr; 32with Exp_Ch2; use Exp_Ch2; 33with Exp_Ch3; use Exp_Ch3; 34with Exp_Ch4; use Exp_Ch4; 35with Exp_Ch5; use Exp_Ch5; 36with Exp_Ch6; use Exp_Ch6; 37with Exp_Ch7; use Exp_Ch7; 38with Exp_Ch8; use Exp_Ch8; 39with Exp_Ch9; use Exp_Ch9; 40with Exp_Ch11; use Exp_Ch11; 41with Exp_Ch12; use Exp_Ch12; 42with Exp_Ch13; use Exp_Ch13; 43with Exp_Prag; use Exp_Prag; 44with Ghost; use Ghost; 45with Opt; use Opt; 46with Rtsfind; use Rtsfind; 47with Sem; use Sem; 48with Sem_Ch8; use Sem_Ch8; 49with Sem_Util; use Sem_Util; 50with Sinfo; use Sinfo; 51with Table; 52 53package body Expander is 54 55 ---------------- 56 -- Local Data -- 57 ---------------- 58 59 -- The following table is used to save values of the Expander_Active flag 60 -- when they are saved by Expander_Mode_Save_And_Set. We use an extendible 61 -- table (which is a bit of overkill) because it is easier than figuring 62 -- out a maximum value or bothering with range checks. 63 64 package Expander_Flags is new Table.Table ( 65 Table_Component_Type => Boolean, 66 Table_Index_Type => Int, 67 Table_Low_Bound => 0, 68 Table_Initial => 32, 69 Table_Increment => 200, 70 Table_Name => "Expander_Flags"); 71 72 Abort_Bug_Box_Error : exception; 73 -- Arbitrary exception to raise for implementation of -gnatd.B. See "when 74 -- N_Abort_Statement" below. See also debug.adb. 75 76 ------------ 77 -- Expand -- 78 ------------ 79 80 -- WARNING: This routine manages Ghost regions. Return statements must be 81 -- replaced by gotos which jump to the end of the routine and restore the 82 -- Ghost mode. 83 84 procedure Expand (N : Node_Id) is 85 Saved_GM : constant Ghost_Mode_Type := Ghost_Mode; 86 -- Save the Ghost mode to restore on exit 87 88 begin 89 -- If we were analyzing a default expression (or other spec expression) 90 -- the Full_Analysis flag must be off. If we are in expansion mode then 91 -- we must be performing a full analysis. If we are analyzing a generic 92 -- then Expansion must be off. 93 94 pragma Assert 95 (not (Full_Analysis and then In_Spec_Expression) 96 and then (Full_Analysis or else not Expander_Active) 97 and then not (Inside_A_Generic and then Expander_Active)); 98 99 -- Establish the Ghost mode of the context to ensure that any generated 100 -- nodes during expansion are marked as Ghost. 101 102 Set_Ghost_Mode (N); 103 104 -- The GNATprove_Mode flag indicates that a light expansion for formal 105 -- verification should be used. This expansion is never done inside 106 -- generics, because otherwise, this breaks the name resolution 107 -- mechanism for generic instances. 108 109 if GNATprove_Mode then 110 if not Inside_A_Generic then 111 Expand_SPARK (N); 112 end if; 113 114 Set_Analyzed (N, Full_Analysis); 115 116 -- Regular expansion is normally followed by special handling for 117 -- transient scopes for unconstrained results, etc. but this is not 118 -- needed, and in general cannot be done correctly, in this mode, so 119 -- we are all done. 120 121 goto Leave; 122 123 -- There are three reasons for the Expander_Active flag to be false 124 125 -- The first is when are not generating code. In this mode the 126 -- Full_Analysis flag indicates whether we are performing a complete 127 -- analysis, in which case Full_Analysis = True or a pre-analysis in 128 -- which case Full_Analysis = False. See the spec of Sem for more info 129 -- on this. 130 131 -- The second reason for the Expander_Active flag to be False is that 132 -- we are performing a pre-analysis. During pre-analysis all expansion 133 -- activity is turned off to make sure nodes are semantically decorated 134 -- but no extra nodes are generated. This is for instance needed for 135 -- the first pass of aggregate semantic processing. Note that in this 136 -- case the Full_Analysis flag is set to False because the node will 137 -- subsequently be re-analyzed with expansion on (see the spec of sem). 138 139 -- Finally, expansion is turned off in a regular compilation if there 140 -- are serious errors. In that case there will be no further expansion, 141 -- but one cleanup action may be required: if a transient scope was 142 -- created (e.g. for a function that returns an unconstrained type) the 143 -- scope may still be on the stack, and must be removed explicitly, 144 -- given that the expansion actions that would normally process it will 145 -- not take place. This prevents cascaded errors due to stack mismatch. 146 147 elsif not Expander_Active then 148 Set_Analyzed (N, Full_Analysis); 149 150 if Serious_Errors_Detected > 0 and then Scope_Is_Transient then 151 Scope_Stack.Table 152 (Scope_Stack.Last).Actions_To_Be_Wrapped := (others => No_List); 153 Pop_Scope; 154 end if; 155 156 goto Leave; 157 158 else 159 begin 160 Debug_A_Entry ("expanding ", N); 161 162 -- Processing depends on node kind. For full details on the 163 -- expansion activity required in each case, see bodies of 164 -- corresponding expand routines. 165 166 case Nkind (N) is 167 when N_Abort_Statement => 168 Expand_N_Abort_Statement (N); 169 170 -- If -gnatd.B switch was given, crash the compiler. See 171 -- debug.adb for explanation. 172 173 if Debug_Flag_Dot_BB then 174 raise Abort_Bug_Box_Error; 175 end if; 176 177 when N_Accept_Statement => 178 Expand_N_Accept_Statement (N); 179 180 when N_Aggregate => 181 Expand_N_Aggregate (N); 182 183 when N_Allocator => 184 Expand_N_Allocator (N); 185 186 when N_And_Then => 187 Expand_N_And_Then (N); 188 189 when N_Assignment_Statement => 190 Expand_N_Assignment_Statement (N); 191 192 when N_Asynchronous_Select => 193 Expand_N_Asynchronous_Select (N); 194 195 when N_Attribute_Definition_Clause => 196 Expand_N_Attribute_Definition_Clause (N); 197 198 when N_Attribute_Reference => 199 Expand_N_Attribute_Reference (N); 200 201 when N_Block_Statement => 202 Expand_N_Block_Statement (N); 203 204 when N_Case_Expression => 205 Expand_N_Case_Expression (N); 206 207 when N_Case_Statement => 208 Expand_N_Case_Statement (N); 209 210 when N_Conditional_Entry_Call => 211 Expand_N_Conditional_Entry_Call (N); 212 213 when N_Delay_Relative_Statement => 214 Expand_N_Delay_Relative_Statement (N); 215 216 when N_Delay_Until_Statement => 217 Expand_N_Delay_Until_Statement (N); 218 219 when N_Delta_Aggregate => 220 Expand_N_Delta_Aggregate (N); 221 222 when N_Entry_Body => 223 Expand_N_Entry_Body (N); 224 225 when N_Entry_Call_Statement => 226 Expand_N_Entry_Call_Statement (N); 227 228 when N_Entry_Declaration => 229 Expand_N_Entry_Declaration (N); 230 231 when N_Exception_Declaration => 232 Expand_N_Exception_Declaration (N); 233 234 when N_Exception_Renaming_Declaration => 235 Expand_N_Exception_Renaming_Declaration (N); 236 237 when N_Exit_Statement => 238 Expand_N_Exit_Statement (N); 239 240 when N_Expanded_Name => 241 Expand_N_Expanded_Name (N); 242 243 when N_Explicit_Dereference => 244 Expand_N_Explicit_Dereference (N); 245 246 when N_Expression_With_Actions => 247 Expand_N_Expression_With_Actions (N); 248 249 when N_Extended_Return_Statement => 250 Expand_N_Extended_Return_Statement (N); 251 252 when N_Extension_Aggregate => 253 Expand_N_Extension_Aggregate (N); 254 255 when N_Free_Statement => 256 Expand_N_Free_Statement (N); 257 258 when N_Freeze_Entity => 259 Expand_N_Freeze_Entity (N); 260 261 when N_Full_Type_Declaration => 262 Expand_N_Full_Type_Declaration (N); 263 264 when N_Function_Call => 265 Expand_N_Function_Call (N); 266 267 when N_Generic_Instantiation => 268 Expand_N_Generic_Instantiation (N); 269 270 when N_Goto_Statement => 271 Expand_N_Goto_Statement (N); 272 273 when N_Handled_Sequence_Of_Statements => 274 Expand_N_Handled_Sequence_Of_Statements (N); 275 276 when N_Identifier => 277 Expand_N_Identifier (N); 278 279 when N_If_Expression => 280 Expand_N_If_Expression (N); 281 282 when N_Indexed_Component => 283 Expand_N_Indexed_Component (N); 284 285 when N_If_Statement => 286 Expand_N_If_Statement (N); 287 288 when N_In => 289 Expand_N_In (N); 290 291 when N_Loop_Statement => 292 Expand_N_Loop_Statement (N); 293 294 when N_Not_In => 295 Expand_N_Not_In (N); 296 297 when N_Null => 298 Expand_N_Null (N); 299 300 when N_Object_Declaration => 301 Expand_N_Object_Declaration (N); 302 303 when N_Object_Renaming_Declaration => 304 Expand_N_Object_Renaming_Declaration (N); 305 306 when N_Op_Add => 307 Expand_N_Op_Add (N); 308 309 when N_Op_Abs => 310 Expand_N_Op_Abs (N); 311 312 when N_Op_And => 313 Expand_N_Op_And (N); 314 315 when N_Op_Concat => 316 Expand_N_Op_Concat (N); 317 318 when N_Op_Divide => 319 Expand_N_Op_Divide (N); 320 321 when N_Op_Eq => 322 Expand_N_Op_Eq (N); 323 324 when N_Op_Expon => 325 Expand_N_Op_Expon (N); 326 327 when N_Op_Ge => 328 Expand_N_Op_Ge (N); 329 330 when N_Op_Gt => 331 Expand_N_Op_Gt (N); 332 333 when N_Op_Le => 334 Expand_N_Op_Le (N); 335 336 when N_Op_Lt => 337 Expand_N_Op_Lt (N); 338 339 when N_Op_Minus => 340 Expand_N_Op_Minus (N); 341 342 when N_Op_Mod => 343 Expand_N_Op_Mod (N); 344 345 when N_Op_Multiply => 346 Expand_N_Op_Multiply (N); 347 348 when N_Op_Ne => 349 Expand_N_Op_Ne (N); 350 351 when N_Op_Not => 352 Expand_N_Op_Not (N); 353 354 when N_Op_Or => 355 Expand_N_Op_Or (N); 356 357 when N_Op_Plus => 358 Expand_N_Op_Plus (N); 359 360 when N_Op_Rem => 361 Expand_N_Op_Rem (N); 362 363 when N_Op_Rotate_Left => 364 Expand_N_Op_Rotate_Left (N); 365 366 when N_Op_Rotate_Right => 367 Expand_N_Op_Rotate_Right (N); 368 369 when N_Op_Shift_Left => 370 Expand_N_Op_Shift_Left (N); 371 372 when N_Op_Shift_Right => 373 Expand_N_Op_Shift_Right (N); 374 375 when N_Op_Shift_Right_Arithmetic => 376 Expand_N_Op_Shift_Right_Arithmetic (N); 377 378 when N_Op_Subtract => 379 Expand_N_Op_Subtract (N); 380 381 when N_Op_Xor => 382 Expand_N_Op_Xor (N); 383 384 when N_Or_Else => 385 Expand_N_Or_Else (N); 386 387 when N_Package_Body => 388 Expand_N_Package_Body (N); 389 390 when N_Package_Declaration => 391 Expand_N_Package_Declaration (N); 392 393 when N_Package_Renaming_Declaration => 394 Expand_N_Package_Renaming_Declaration (N); 395 396 when N_Subprogram_Renaming_Declaration => 397 Expand_N_Subprogram_Renaming_Declaration (N); 398 399 when N_Pragma => 400 Expand_N_Pragma (N); 401 402 when N_Procedure_Call_Statement => 403 Expand_N_Procedure_Call_Statement (N); 404 405 when N_Protected_Type_Declaration => 406 Expand_N_Protected_Type_Declaration (N); 407 408 when N_Protected_Body => 409 Expand_N_Protected_Body (N); 410 411 when N_Qualified_Expression => 412 Expand_N_Qualified_Expression (N); 413 414 when N_Quantified_Expression => 415 Expand_N_Quantified_Expression (N); 416 417 when N_Raise_Statement => 418 Expand_N_Raise_Statement (N); 419 420 when N_Raise_Constraint_Error => 421 Expand_N_Raise_Constraint_Error (N); 422 423 when N_Raise_Expression => 424 Expand_N_Raise_Expression (N); 425 426 when N_Raise_Program_Error => 427 Expand_N_Raise_Program_Error (N); 428 429 when N_Raise_Storage_Error => 430 Expand_N_Raise_Storage_Error (N); 431 432 when N_Real_Literal => 433 Expand_N_Real_Literal (N); 434 435 when N_Record_Representation_Clause => 436 Expand_N_Record_Representation_Clause (N); 437 438 when N_Reduction_Expression => 439 Expand_N_Reduction_Expression (N); 440 441 when N_Requeue_Statement => 442 Expand_N_Requeue_Statement (N); 443 444 when N_Simple_Return_Statement => 445 Expand_N_Simple_Return_Statement (N); 446 447 when N_Selected_Component => 448 Expand_N_Selected_Component (N); 449 450 when N_Selective_Accept => 451 Expand_N_Selective_Accept (N); 452 453 when N_Single_Protected_Declaration => 454 Expand_N_Single_Protected_Declaration (N); 455 456 when N_Single_Task_Declaration => 457 Expand_N_Single_Task_Declaration (N); 458 459 when N_Slice => 460 Expand_N_Slice (N); 461 462 when N_Subtype_Indication => 463 Expand_N_Subtype_Indication (N); 464 465 when N_Subprogram_Body => 466 Expand_N_Subprogram_Body (N); 467 468 when N_Subprogram_Body_Stub => 469 Expand_N_Subprogram_Body_Stub (N); 470 471 when N_Subprogram_Declaration => 472 Expand_N_Subprogram_Declaration (N); 473 474 when N_Task_Body => 475 Expand_N_Task_Body (N); 476 477 when N_Task_Type_Declaration => 478 Expand_N_Task_Type_Declaration (N); 479 480 when N_Timed_Entry_Call => 481 Expand_N_Timed_Entry_Call (N); 482 483 when N_Type_Conversion => 484 Expand_N_Type_Conversion (N); 485 486 when N_Unchecked_Expression => 487 Expand_N_Unchecked_Expression (N); 488 489 when N_Unchecked_Type_Conversion => 490 Expand_N_Unchecked_Type_Conversion (N); 491 492 when N_Variant_Part => 493 Expand_N_Variant_Part (N); 494 495 -- For all other node kinds, no expansion activity required 496 497 when others => 498 null; 499 end case; 500 501 exception 502 when RE_Not_Available => 503 goto Leave; 504 end; 505 506 -- Set result as analyzed and then do a possible transient wrap. The 507 -- transient wrap must be done after the Analyzed flag is set on, so 508 -- that we do not get a recursive attempt to expand the node N. 509 510 Set_Analyzed (N); 511 512 -- Deal with transient scopes 513 514 if Scope_Is_Transient and then N = Node_To_Be_Wrapped then 515 case Nkind (N) is 516 when N_Procedure_Call_Statement 517 | N_Statement_Other_Than_Procedure_Call 518 => 519 Wrap_Transient_Statement (N); 520 521 when N_Object_Declaration 522 | N_Object_Renaming_Declaration 523 | N_Subtype_Declaration 524 => 525 Wrap_Transient_Declaration (N); 526 527 when others => 528 Wrap_Transient_Expression (N); 529 end case; 530 end if; 531 532 Debug_A_Exit ("expanding ", N, " (done)"); 533 end if; 534 535 <<Leave>> 536 Restore_Ghost_Mode (Saved_GM); 537 end Expand; 538 539 --------------------------- 540 -- Expander_Mode_Restore -- 541 --------------------------- 542 543 procedure Expander_Mode_Restore is 544 begin 545 -- Not active (has no effect) in ASIS and GNATprove modes (see comments 546 -- in spec of Expander_Mode_Save_And_Set). 547 548 if ASIS_Mode or GNATprove_Mode then 549 return; 550 end if; 551 552 -- Otherwise restore the flag 553 554 Expander_Active := Expander_Flags.Table (Expander_Flags.Last); 555 Expander_Flags.Decrement_Last; 556 557 -- Keep expander off if serious errors detected. In this case we do not 558 -- need expansion, and continued expansion may cause cascaded errors or 559 -- compiler bombs. 560 561 if Serious_Errors_Detected /= 0 then 562 Expander_Active := False; 563 end if; 564 end Expander_Mode_Restore; 565 566 -------------------------------- 567 -- Expander_Mode_Save_And_Set -- 568 -------------------------------- 569 570 procedure Expander_Mode_Save_And_Set (Status : Boolean) is 571 begin 572 -- Not active (has no effect) in ASIS and GNATprove modes (see comments 573 -- in spec of Expander_Mode_Save_And_Set). 574 575 if ASIS_Mode or GNATprove_Mode then 576 return; 577 end if; 578 579 -- Otherwise save and set the flag 580 581 Expander_Flags.Increment_Last; 582 Expander_Flags.Table (Expander_Flags.Last) := Expander_Active; 583 Expander_Active := Status; 584 end Expander_Mode_Save_And_Set; 585 586end Expander; 587