1 /****************************************************************************** 2 * 3 * Module Name: aslmethod.c - Control method analysis walk 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2019, Intel Corp. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions, and the following disclaimer, 16 * without modification. 17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer 18 * substantially similar to the "NO WARRANTY" disclaimer below 19 * ("Disclaimer") and any redistribution must be conditioned upon 20 * including a substantially similar Disclaimer requirement for further 21 * binary redistribution. 22 * 3. Neither the names of the above-listed copyright holders nor the names 23 * of any contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * Alternatively, this software may be distributed under the terms of the 27 * GNU General Public License ("GPL") version 2 as published by the Free 28 * Software Foundation. 29 * 30 * NO WARRANTY 31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR 34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 41 * POSSIBILITY OF SUCH DAMAGES. 42 */ 43 44 #include "aslcompiler.h" 45 #include "aslcompiler.y.h" 46 #include "acparser.h" 47 #include "amlcode.h" 48 49 50 #define _COMPONENT ACPI_COMPILER 51 ACPI_MODULE_NAME ("aslmethod") 52 53 54 /* Local prototypes */ 55 56 static void 57 MtCheckNamedObjectInMethod ( 58 ACPI_PARSE_OBJECT *Op, 59 ASL_METHOD_INFO *MethodInfo); 60 61 62 /******************************************************************************* 63 * 64 * FUNCTION: MtMethodAnalysisWalkBegin 65 * 66 * PARAMETERS: ASL_WALK_CALLBACK 67 * 68 * RETURN: Status 69 * 70 * DESCRIPTION: Descending callback for the analysis walk. Check methods for: 71 * 1) Initialized local variables 72 * 2) Valid arguments 73 * 3) Return types 74 * 75 ******************************************************************************/ 76 77 ACPI_STATUS 78 MtMethodAnalysisWalkBegin ( 79 ACPI_PARSE_OBJECT *Op, 80 UINT32 Level, 81 void *Context) 82 { 83 ASL_ANALYSIS_WALK_INFO *WalkInfo = (ASL_ANALYSIS_WALK_INFO *) Context; 84 ASL_METHOD_INFO *MethodInfo = WalkInfo->MethodStack; 85 ACPI_PARSE_OBJECT *Next; 86 UINT32 RegisterNumber; 87 UINT32 i; 88 char LocalName[] = "Local0"; 89 char ArgName[] = "Arg0"; 90 ACPI_PARSE_OBJECT *ArgNode; 91 ACPI_PARSE_OBJECT *NextType; 92 ACPI_PARSE_OBJECT *NextParamType; 93 UINT8 ActualArgs = 0; 94 95 96 /* Build cross-reference output file if requested */ 97 98 if (AslGbl_CrossReferenceOutput) 99 { 100 OtXrefWalkPart1 (Op, Level, MethodInfo); 101 } 102 103 switch (Op->Asl.ParseOpcode) 104 { 105 case PARSEOP_METHOD: 106 107 AslGbl_TotalMethods++; 108 109 /* Create and init method info */ 110 111 MethodInfo = UtLocalCalloc (sizeof (ASL_METHOD_INFO)); 112 MethodInfo->Next = WalkInfo->MethodStack; 113 MethodInfo->Op = Op; 114 115 WalkInfo->MethodStack = MethodInfo; 116 117 /* 118 * Special handling for _PSx methods. Dependency rules (same scope): 119 * 120 * 1) _PS0 - One of these must exist: _PS1, _PS2, _PS3 121 * 2) _PS1/_PS2/_PS3: A _PS0 must exist 122 */ 123 if (ACPI_COMPARE_NAMESEG (METHOD_NAME__PS0, Op->Asl.NameSeg)) 124 { 125 /* For _PS0, one of _PS1/_PS2/_PS3 must exist */ 126 127 if ((!ApFindNameInScope (METHOD_NAME__PS1, Op)) && 128 (!ApFindNameInScope (METHOD_NAME__PS2, Op)) && 129 (!ApFindNameInScope (METHOD_NAME__PS3, Op))) 130 { 131 AslError (ASL_WARNING, ASL_MSG_MISSING_DEPENDENCY, Op, 132 "_PS0 requires one of _PS1/_PS2/_PS3 in same scope"); 133 } 134 } 135 else if ( 136 ACPI_COMPARE_NAMESEG (METHOD_NAME__PS1, Op->Asl.NameSeg) || 137 ACPI_COMPARE_NAMESEG (METHOD_NAME__PS2, Op->Asl.NameSeg) || 138 ACPI_COMPARE_NAMESEG (METHOD_NAME__PS3, Op->Asl.NameSeg)) 139 { 140 /* For _PS1/_PS2/_PS3, a _PS0 must exist */ 141 142 if (!ApFindNameInScope (METHOD_NAME__PS0, Op)) 143 { 144 sprintf (AslGbl_MsgBuffer, 145 "%4.4s requires _PS0 in same scope", Op->Asl.NameSeg); 146 147 AslError (ASL_WARNING, ASL_MSG_MISSING_DEPENDENCY, Op, 148 AslGbl_MsgBuffer); 149 } 150 } 151 152 /* Get the name node */ 153 154 Next = Op->Asl.Child; 155 156 /* Get the NumArguments node */ 157 158 Next = Next->Asl.Next; 159 MethodInfo->NumArguments = (UINT8) 160 (((UINT8) Next->Asl.Value.Integer) & 0x07); 161 162 /* Get the SerializeRule and SyncLevel nodes, ignored here */ 163 164 Next = Next->Asl.Next; 165 MethodInfo->ShouldBeSerialized = (UINT8) Next->Asl.Value.Integer; 166 167 Next = Next->Asl.Next; 168 ArgNode = Next; 169 170 /* Get the ReturnType node */ 171 172 Next = Next->Asl.Next; 173 174 NextType = Next->Asl.Child; 175 while (NextType) 176 { 177 /* Get and map each of the ReturnTypes */ 178 179 MethodInfo->ValidReturnTypes |= AnMapObjTypeToBtype (NextType); 180 NextType->Asl.ParseOpcode = PARSEOP_DEFAULT_ARG; 181 NextType = NextType->Asl.Next; 182 } 183 184 /* Get the ParameterType node */ 185 186 Next = Next->Asl.Next; 187 188 NextType = Next->Asl.Child; 189 while (NextType) 190 { 191 if (NextType->Asl.ParseOpcode == PARSEOP_DEFAULT_ARG) 192 { 193 NextParamType = NextType->Asl.Child; 194 while (NextParamType) 195 { 196 MethodInfo->ValidArgTypes[ActualArgs] |= 197 AnMapObjTypeToBtype (NextParamType); 198 199 NextParamType->Asl.ParseOpcode = PARSEOP_DEFAULT_ARG; 200 NextParamType = NextParamType->Asl.Next; 201 } 202 } 203 else 204 { 205 MethodInfo->ValidArgTypes[ActualArgs] = 206 AnMapObjTypeToBtype (NextType); 207 208 NextType->Asl.ParseOpcode = PARSEOP_DEFAULT_ARG; 209 ActualArgs++; 210 } 211 212 NextType = NextType->Asl.Next; 213 } 214 215 if ((MethodInfo->NumArguments) && 216 (MethodInfo->NumArguments != ActualArgs)) 217 { 218 /* error: Param list did not match number of args */ 219 } 220 221 /* Allow numarguments == 0 for Function() */ 222 223 if ((!MethodInfo->NumArguments) && (ActualArgs)) 224 { 225 MethodInfo->NumArguments = ActualArgs; 226 ArgNode->Asl.Value.Integer |= ActualArgs; 227 } 228 229 /* 230 * Actual arguments are initialized at method entry. 231 * All other ArgX "registers" can be used as locals, so we 232 * track their initialization. 233 */ 234 for (i = 0; i < MethodInfo->NumArguments; i++) 235 { 236 MethodInfo->ArgInitialized[i] = TRUE; 237 } 238 break; 239 240 case PARSEOP_METHODCALL: 241 242 /* Check for a recursive method call */ 243 244 if (MethodInfo && 245 (Op->Asl.Node == MethodInfo->Op->Asl.Node)) 246 { 247 if (MethodInfo->CreatesNamedObjects) 248 { 249 /* 250 * This is an error, as it will fail at runtime on all ACPI 251 * implementations. Any named object declarations will be 252 * executed twice, causing failure the second time. Note, 253 * this is independent of whether the method is declared 254 * Serialized, because the same thread is attempting to 255 * reenter the method, and this will always succeed. 256 */ 257 AslDualParseOpError (ASL_ERROR, ASL_MSG_ILLEGAL_RECURSION, Op, 258 Op->Asl.Value.String, ASL_MSG_FOUND_HERE, MethodInfo->Op, 259 MethodInfo->Op->Asl.ExternalName); 260 } 261 else 262 { 263 /* Method does not create objects, issue a remark */ 264 265 AslError (ASL_REMARK, ASL_MSG_RECURSION, Op, Op->Asl.ExternalName); 266 } 267 } 268 break; 269 270 case PARSEOP_LOCAL0: 271 case PARSEOP_LOCAL1: 272 case PARSEOP_LOCAL2: 273 case PARSEOP_LOCAL3: 274 case PARSEOP_LOCAL4: 275 case PARSEOP_LOCAL5: 276 case PARSEOP_LOCAL6: 277 case PARSEOP_LOCAL7: 278 279 if (!MethodInfo) 280 { 281 /* 282 * Local was used outside a control method, or there was an error 283 * in the method declaration. 284 */ 285 AslError (ASL_REMARK, ASL_MSG_LOCAL_OUTSIDE_METHOD, 286 Op, Op->Asl.ExternalName); 287 return (AE_ERROR); 288 } 289 290 RegisterNumber = (Op->Asl.AmlOpcode & 0x0007); 291 292 /* 293 * If the local is being used as a target, mark the local 294 * initialized 295 */ 296 if (Op->Asl.CompileFlags & OP_IS_TARGET) 297 { 298 MethodInfo->LocalInitialized[RegisterNumber] = TRUE; 299 } 300 301 /* 302 * Otherwise, this is a reference, check if the local 303 * has been previously initialized. 304 * 305 * The only operator that accepts an uninitialized value is ObjectType() 306 */ 307 else if ((!MethodInfo->LocalInitialized[RegisterNumber]) && 308 (Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_OBJECTTYPE)) 309 { 310 LocalName[strlen (LocalName) -1] = (char) (RegisterNumber + 0x30); 311 AslError (ASL_ERROR, ASL_MSG_LOCAL_INIT, Op, LocalName); 312 } 313 break; 314 315 case PARSEOP_ARG0: 316 case PARSEOP_ARG1: 317 case PARSEOP_ARG2: 318 case PARSEOP_ARG3: 319 case PARSEOP_ARG4: 320 case PARSEOP_ARG5: 321 case PARSEOP_ARG6: 322 323 if (!MethodInfo) 324 { 325 /* 326 * Arg was used outside a control method, or there was an error 327 * in the method declaration. 328 */ 329 AslError (ASL_REMARK, ASL_MSG_LOCAL_OUTSIDE_METHOD, 330 Op, Op->Asl.ExternalName); 331 return (AE_ERROR); 332 } 333 334 RegisterNumber = (Op->Asl.AmlOpcode & 0x000F) - 8; 335 ArgName[strlen (ArgName) -1] = (char) (RegisterNumber + 0x30); 336 337 /* 338 * If the Arg is being used as a target, mark the local 339 * initialized 340 */ 341 if (Op->Asl.CompileFlags & OP_IS_TARGET) 342 { 343 MethodInfo->ArgInitialized[RegisterNumber] = TRUE; 344 } 345 346 /* 347 * Otherwise, this is a reference, check if the Arg 348 * has been previously initialized. 349 * 350 * The only operator that accepts an uninitialized value is ObjectType() 351 */ 352 else if ((!MethodInfo->ArgInitialized[RegisterNumber]) && 353 (Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_OBJECTTYPE)) 354 { 355 AslError (ASL_ERROR, ASL_MSG_ARG_INIT, Op, ArgName); 356 } 357 358 /* Flag this arg if it is not a "real" argument to the method */ 359 360 if (RegisterNumber >= MethodInfo->NumArguments) 361 { 362 AslError (ASL_REMARK, ASL_MSG_NOT_PARAMETER, Op, ArgName); 363 } 364 break; 365 366 case PARSEOP_RETURN: 367 368 if (!MethodInfo) 369 { 370 /* 371 * Probably was an error in the method declaration, 372 * no additional error here 373 */ 374 ACPI_WARNING ((AE_INFO, "%p, No parent method", Op)); 375 return (AE_ERROR); 376 } 377 378 /* 379 * A child indicates a possible return value. A simple Return or 380 * Return() is marked with OP_IS_NULL_RETURN by the parser so 381 * that it is not counted as a "real" return-with-value, although 382 * the AML code that is actually emitted is Return(0). The AML 383 * definition of Return has a required parameter, so we are 384 * forced to convert a null return to Return(0). 385 */ 386 if ((Op->Asl.Child) && 387 (Op->Asl.Child->Asl.ParseOpcode != PARSEOP_DEFAULT_ARG) && 388 (!(Op->Asl.Child->Asl.CompileFlags & OP_IS_NULL_RETURN))) 389 { 390 MethodInfo->NumReturnWithValue++; 391 } 392 else 393 { 394 MethodInfo->NumReturnNoValue++; 395 } 396 break; 397 398 case PARSEOP_BREAK: 399 case PARSEOP_CONTINUE: 400 401 Next = Op->Asl.Parent; 402 while (Next) 403 { 404 if (Next->Asl.ParseOpcode == PARSEOP_WHILE) 405 { 406 break; 407 } 408 Next = Next->Asl.Parent; 409 } 410 411 if (!Next) 412 { 413 AslError (ASL_ERROR, ASL_MSG_NO_WHILE, Op, NULL); 414 } 415 break; 416 417 case PARSEOP_STALL: 418 419 /* We can range check if the argument is an integer */ 420 421 if ((Op->Asl.Child->Asl.ParseOpcode == PARSEOP_INTEGER) && 422 (Op->Asl.Child->Asl.Value.Integer > ACPI_UINT8_MAX)) 423 { 424 AslError (ASL_ERROR, ASL_MSG_INVALID_TIME, Op, NULL); 425 } 426 break; 427 428 case PARSEOP_DEVICE: 429 430 if (!ApFindNameInDeviceTree (METHOD_NAME__HID, Op) && 431 !ApFindNameInDeviceTree (METHOD_NAME__ADR, Op)) 432 { 433 AslError (ASL_WARNING, ASL_MSG_MISSING_DEPENDENCY, Op, 434 "Device object requires a _HID or _ADR in same scope"); 435 } 436 break; 437 438 case PARSEOP_EVENT: 439 case PARSEOP_MUTEX: 440 case PARSEOP_OPERATIONREGION: 441 case PARSEOP_POWERRESOURCE: 442 case PARSEOP_PROCESSOR: 443 case PARSEOP_THERMALZONE: 444 445 /* 446 * The first operand is a name to be created in the namespace. 447 * Check against the reserved list. 448 */ 449 i = ApCheckForPredefinedName (Op, Op->Asl.NameSeg); 450 if (i < ACPI_VALID_RESERVED_NAME_MAX) 451 { 452 AslError (ASL_ERROR, ASL_MSG_RESERVED_USE, 453 Op, Op->Asl.ExternalName); 454 } 455 break; 456 457 case PARSEOP_NAME: 458 459 /* Typecheck any predefined names statically defined with Name() */ 460 461 ApCheckForPredefinedObject (Op, Op->Asl.NameSeg); 462 463 /* Special typechecking for _HID */ 464 465 if (!strcmp (METHOD_NAME__HID, Op->Asl.NameSeg)) 466 { 467 Next = Op->Asl.Child->Asl.Next; 468 AnCheckId (Next, ASL_TYPE_HID); 469 } 470 471 /* Special typechecking for _CID */ 472 473 else if (!strcmp (METHOD_NAME__CID, Op->Asl.NameSeg)) 474 { 475 Next = Op->Asl.Child->Asl.Next; 476 477 if ((Next->Asl.ParseOpcode == PARSEOP_PACKAGE) || 478 (Next->Asl.ParseOpcode == PARSEOP_VAR_PACKAGE)) 479 { 480 Next = Next->Asl.Child; 481 while (Next) 482 { 483 AnCheckId (Next, ASL_TYPE_CID); 484 Next = Next->Asl.Next; 485 } 486 } 487 else 488 { 489 AnCheckId (Next, ASL_TYPE_CID); 490 } 491 } 492 493 break; 494 495 default: 496 497 break; 498 } 499 500 /* Check for named object creation within a non-serialized method */ 501 502 MtCheckNamedObjectInMethod (Op, MethodInfo); 503 return (AE_OK); 504 } 505 506 507 /******************************************************************************* 508 * 509 * FUNCTION: MtCheckNamedObjectInMethod 510 * 511 * PARAMETERS: Op - Current parser op 512 * MethodInfo - Info for method being parsed 513 * 514 * RETURN: None 515 * 516 * DESCRIPTION: Detect if a non-serialized method is creating a named object, 517 * which could possibly cause problems if two threads execute 518 * the method concurrently. Emit a remark in this case. 519 * 520 ******************************************************************************/ 521 522 static void 523 MtCheckNamedObjectInMethod ( 524 ACPI_PARSE_OBJECT *Op, 525 ASL_METHOD_INFO *MethodInfo) 526 { 527 const ACPI_OPCODE_INFO *OpInfo; 528 529 530 /* We don't care about actual method declarations or scopes */ 531 532 if ((Op->Asl.AmlOpcode == AML_METHOD_OP) || 533 (Op->Asl.AmlOpcode == AML_SCOPE_OP)) 534 { 535 return; 536 } 537 538 /* Determine if we are creating a named object within a method */ 539 540 if (!MethodInfo) 541 { 542 return; 543 } 544 545 OpInfo = AcpiPsGetOpcodeInfo (Op->Asl.AmlOpcode); 546 if (OpInfo->Class == AML_CLASS_NAMED_OBJECT) 547 { 548 /* 549 * 1) Mark the method as a method that creates named objects. 550 * 551 * 2) If the method is non-serialized, emit a remark that the method 552 * should be serialized. 553 * 554 * Reason: If a thread blocks within the method for any reason, and 555 * another thread enters the method, the method will fail because 556 * an attempt will be made to create the same object twice. 557 */ 558 MethodInfo->CreatesNamedObjects = TRUE; 559 if (!MethodInfo->ShouldBeSerialized) 560 { 561 AslError (ASL_REMARK, ASL_MSG_SERIALIZED_REQUIRED, MethodInfo->Op, 562 "due to creation of named objects within"); 563 564 /* Emit message only ONCE per method */ 565 566 MethodInfo->ShouldBeSerialized = TRUE; 567 } 568 } 569 } 570 571 572 /******************************************************************************* 573 * 574 * FUNCTION: MtMethodAnalysisWalkEnd 575 * 576 * PARAMETERS: ASL_WALK_CALLBACK 577 * 578 * RETURN: Status 579 * 580 * DESCRIPTION: Ascending callback for analysis walk. Complete method 581 * return analysis. 582 * 583 ******************************************************************************/ 584 585 ACPI_STATUS 586 MtMethodAnalysisWalkEnd ( 587 ACPI_PARSE_OBJECT *Op, 588 UINT32 Level, 589 void *Context) 590 { 591 ASL_ANALYSIS_WALK_INFO *WalkInfo = (ASL_ANALYSIS_WALK_INFO *) Context; 592 ASL_METHOD_INFO *MethodInfo = WalkInfo->MethodStack; 593 594 595 switch (Op->Asl.ParseOpcode) 596 { 597 case PARSEOP_METHOD: 598 case PARSEOP_RETURN: 599 600 if (!MethodInfo) 601 { 602 printf ("No method info for method! [%s]\n", Op->Asl.Namepath); 603 AslError (ASL_ERROR, ASL_MSG_COMPILER_INTERNAL, Op, 604 "No method info for this method"); 605 606 CmCleanupAndExit (); 607 return (AE_AML_INTERNAL); 608 } 609 break; 610 611 default: 612 613 break; 614 } 615 616 switch (Op->Asl.ParseOpcode) 617 { 618 case PARSEOP_METHOD: 619 620 WalkInfo->MethodStack = MethodInfo->Next; 621 622 /* 623 * Check if there is no return statement at the end of the 624 * method AND we can actually get there -- i.e., the execution 625 * of the method can possibly terminate without a return statement. 626 */ 627 if ((!AnLastStatementIsReturn (Op)) && 628 (!(Op->Asl.CompileFlags & OP_HAS_NO_EXIT))) 629 { 630 /* 631 * No return statement, and execution can possibly exit 632 * via this path. This is equivalent to Return () 633 */ 634 MethodInfo->NumReturnNoValue++; 635 } 636 637 /* 638 * Check for case where some return statements have a return value 639 * and some do not. Exit without a return statement is a return with 640 * no value 641 */ 642 if (MethodInfo->NumReturnNoValue && 643 MethodInfo->NumReturnWithValue) 644 { 645 AslError (ASL_WARNING, ASL_MSG_RETURN_TYPES, Op, 646 Op->Asl.ExternalName); 647 } 648 649 /* 650 * If there are any RETURN() statements with no value, or there is a 651 * control path that allows the method to exit without a return value, 652 * we mark the method as a method that does not return a value. This 653 * knowledge can be used to check method invocations that expect a 654 * returned value. 655 */ 656 if (MethodInfo->NumReturnNoValue) 657 { 658 if (MethodInfo->NumReturnWithValue) 659 { 660 Op->Asl.CompileFlags |= OP_METHOD_SOME_NO_RETVAL; 661 } 662 else 663 { 664 Op->Asl.CompileFlags |= OP_METHOD_NO_RETVAL; 665 } 666 } 667 668 /* 669 * Check predefined method names for correct return behavior 670 * and correct number of arguments. Also, some special checks 671 * For GPE and _REG methods. 672 */ 673 if (ApCheckForPredefinedMethod (Op, MethodInfo)) 674 { 675 /* Special check for two names like _L01 and _E01 in same scope */ 676 677 ApCheckForGpeNameConflict (Op); 678 679 /* 680 * Special check for _REG: Must have an operation region definition 681 * within the same scope! 682 */ 683 ApCheckRegMethod (Op); 684 } 685 686 ACPI_FREE (MethodInfo); 687 break; 688 689 case PARSEOP_NAME: 690 691 /* Special check for two names like _L01 and _E01 in same scope */ 692 693 ApCheckForGpeNameConflict (Op); 694 break; 695 696 case PARSEOP_RETURN: 697 698 /* 699 * If the parent is a predefined method name, attempt to typecheck 700 * the return value. Only static types can be validated. 701 */ 702 ApCheckPredefinedReturnValue (Op, MethodInfo); 703 704 /* 705 * The parent block does not "exit" and continue execution -- the 706 * method is terminated here with the Return() statement. 707 */ 708 Op->Asl.Parent->Asl.CompileFlags |= OP_HAS_NO_EXIT; 709 710 /* Used in the "typing" pass later */ 711 712 Op->Asl.ParentMethod = MethodInfo->Op; 713 714 /* 715 * If there is a peer node after the return statement, then this 716 * node is unreachable code -- i.e., it won't be executed because of 717 * the preceding Return() statement. 718 */ 719 if (Op->Asl.Next) 720 { 721 AslError (ASL_WARNING, ASL_MSG_UNREACHABLE_CODE, 722 Op->Asl.Next, NULL); 723 } 724 break; 725 726 case PARSEOP_IF: 727 728 if ((Op->Asl.CompileFlags & OP_HAS_NO_EXIT) && 729 (Op->Asl.Next) && 730 (Op->Asl.Next->Asl.ParseOpcode == PARSEOP_ELSE)) 731 { 732 /* 733 * This IF has a corresponding ELSE. The IF block has no exit, 734 * (it contains an unconditional Return) 735 * mark the ELSE block to remember this fact. 736 */ 737 Op->Asl.Next->Asl.CompileFlags |= OP_IF_HAS_NO_EXIT; 738 } 739 break; 740 741 case PARSEOP_ELSE: 742 743 if ((Op->Asl.CompileFlags & OP_HAS_NO_EXIT) && 744 (Op->Asl.CompileFlags & OP_IF_HAS_NO_EXIT)) 745 { 746 /* 747 * This ELSE block has no exit and the corresponding IF block 748 * has no exit either. Therefore, the parent node has no exit. 749 */ 750 Op->Asl.Parent->Asl.CompileFlags |= OP_HAS_NO_EXIT; 751 } 752 break; 753 754 755 default: 756 757 if ((Op->Asl.CompileFlags & OP_HAS_NO_EXIT) && 758 (Op->Asl.Parent)) 759 { 760 /* If this node has no exit, then the parent has no exit either */ 761 762 Op->Asl.Parent->Asl.CompileFlags |= OP_HAS_NO_EXIT; 763 } 764 break; 765 } 766 767 return (AE_OK); 768 } 769