xref: /freebsd/sys/contrib/dev/acpica/compiler/aslmethod.c (revision fed1ca4b719c56c930f2259d80663cd34be812bb)
1 /******************************************************************************
2  *
3  * Module Name: aslmethod.c - Control method analysis walk
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2016, 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 <contrib/dev/acpica/compiler/aslcompiler.h>
45 #include "aslcompiler.y.h"
46 #include <contrib/dev/acpica/include/acparser.h>
47 #include <contrib/dev/acpica/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 (Gbl_CrossReferenceOutput)
99     {
100         OtXrefWalkPart1 (Op, Level, MethodInfo);
101     }
102 
103     switch (Op->Asl.ParseOpcode)
104     {
105     case PARSEOP_METHOD:
106 
107         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_NAME (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_NAME (METHOD_NAME__PS1, Op->Asl.NameSeg) ||
137             ACPI_COMPARE_NAME (METHOD_NAME__PS2, Op->Asl.NameSeg) ||
138             ACPI_COMPARE_NAME (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 (MsgBuffer,
145                     "%4.4s requires _PS0 in same scope", Op->Asl.NameSeg);
146 
147                 AslError (ASL_WARNING, ASL_MSG_MISSING_DEPENDENCY, Op,
148                     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         if (MethodInfo &&
243            (Op->Asl.Node == MethodInfo->Op->Asl.Node))
244         {
245             AslError (ASL_REMARK, ASL_MSG_RECURSION, Op, Op->Asl.ExternalName);
246         }
247         break;
248 
249     case PARSEOP_LOCAL0:
250     case PARSEOP_LOCAL1:
251     case PARSEOP_LOCAL2:
252     case PARSEOP_LOCAL3:
253     case PARSEOP_LOCAL4:
254     case PARSEOP_LOCAL5:
255     case PARSEOP_LOCAL6:
256     case PARSEOP_LOCAL7:
257 
258         if (!MethodInfo)
259         {
260             /*
261              * Local was used outside a control method, or there was an error
262              * in the method declaration.
263              */
264             AslError (ASL_REMARK, ASL_MSG_LOCAL_OUTSIDE_METHOD,
265                 Op, Op->Asl.ExternalName);
266             return (AE_ERROR);
267         }
268 
269         RegisterNumber = (Op->Asl.AmlOpcode & 0x0007);
270 
271         /*
272          * If the local is being used as a target, mark the local
273          * initialized
274          */
275         if (Op->Asl.CompileFlags & NODE_IS_TARGET)
276         {
277             MethodInfo->LocalInitialized[RegisterNumber] = TRUE;
278         }
279 
280         /*
281          * Otherwise, this is a reference, check if the local
282          * has been previously initialized.
283          *
284          * The only operator that accepts an uninitialized value is ObjectType()
285          */
286         else if ((!MethodInfo->LocalInitialized[RegisterNumber]) &&
287                  (Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_OBJECTTYPE))
288         {
289             LocalName[strlen (LocalName) -1] = (char) (RegisterNumber + 0x30);
290             AslError (ASL_ERROR, ASL_MSG_LOCAL_INIT, Op, LocalName);
291         }
292         break;
293 
294     case PARSEOP_ARG0:
295     case PARSEOP_ARG1:
296     case PARSEOP_ARG2:
297     case PARSEOP_ARG3:
298     case PARSEOP_ARG4:
299     case PARSEOP_ARG5:
300     case PARSEOP_ARG6:
301 
302         if (!MethodInfo)
303         {
304             /*
305              * Arg was used outside a control method, or there was an error
306              * in the method declaration.
307              */
308             AslError (ASL_REMARK, ASL_MSG_LOCAL_OUTSIDE_METHOD,
309                 Op, Op->Asl.ExternalName);
310             return (AE_ERROR);
311         }
312 
313         RegisterNumber = (Op->Asl.AmlOpcode & 0x000F) - 8;
314         ArgName[strlen (ArgName) -1] = (char) (RegisterNumber + 0x30);
315 
316         /*
317          * If the Arg is being used as a target, mark the local
318          * initialized
319          */
320         if (Op->Asl.CompileFlags & NODE_IS_TARGET)
321         {
322             MethodInfo->ArgInitialized[RegisterNumber] = TRUE;
323         }
324 
325         /*
326          * Otherwise, this is a reference, check if the Arg
327          * has been previously initialized.
328          *
329          * The only operator that accepts an uninitialized value is ObjectType()
330          */
331         else if ((!MethodInfo->ArgInitialized[RegisterNumber]) &&
332             (Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_OBJECTTYPE))
333         {
334             AslError (ASL_ERROR, ASL_MSG_ARG_INIT, Op, ArgName);
335         }
336 
337         /* Flag this arg if it is not a "real" argument to the method */
338 
339         if (RegisterNumber >= MethodInfo->NumArguments)
340         {
341             AslError (ASL_REMARK, ASL_MSG_NOT_PARAMETER, Op, ArgName);
342         }
343         break;
344 
345     case PARSEOP_RETURN:
346 
347         if (!MethodInfo)
348         {
349             /*
350              * Probably was an error in the method declaration,
351              * no additional error here
352              */
353             ACPI_WARNING ((AE_INFO, "%p, No parent method", Op));
354             return (AE_ERROR);
355         }
356 
357         /*
358          * A child indicates a possible return value. A simple Return or
359          * Return() is marked with NODE_IS_NULL_RETURN by the parser so
360          * that it is not counted as a "real" return-with-value, although
361          * the AML code that is actually emitted is Return(0). The AML
362          * definition of Return has a required parameter, so we are
363          * forced to convert a null return to Return(0).
364          */
365         if ((Op->Asl.Child) &&
366             (Op->Asl.Child->Asl.ParseOpcode != PARSEOP_DEFAULT_ARG) &&
367             (!(Op->Asl.Child->Asl.CompileFlags & NODE_IS_NULL_RETURN)))
368         {
369             MethodInfo->NumReturnWithValue++;
370         }
371         else
372         {
373             MethodInfo->NumReturnNoValue++;
374         }
375         break;
376 
377     case PARSEOP_BREAK:
378     case PARSEOP_CONTINUE:
379 
380         Next = Op->Asl.Parent;
381         while (Next)
382         {
383             if (Next->Asl.ParseOpcode == PARSEOP_WHILE)
384             {
385                 break;
386             }
387             Next = Next->Asl.Parent;
388         }
389 
390         if (!Next)
391         {
392             AslError (ASL_ERROR, ASL_MSG_NO_WHILE, Op, NULL);
393         }
394         break;
395 
396     case PARSEOP_STALL:
397 
398         /* We can range check if the argument is an integer */
399 
400         if ((Op->Asl.Child->Asl.ParseOpcode == PARSEOP_INTEGER) &&
401             (Op->Asl.Child->Asl.Value.Integer > ACPI_UINT8_MAX))
402         {
403             AslError (ASL_ERROR, ASL_MSG_INVALID_TIME, Op, NULL);
404         }
405         break;
406 
407     case PARSEOP_DEVICE:
408 
409         if (!ApFindNameInDeviceTree (METHOD_NAME__HID, Op) &&
410             !ApFindNameInDeviceTree (METHOD_NAME__ADR, Op))
411         {
412             AslError (ASL_WARNING, ASL_MSG_MISSING_DEPENDENCY, Op,
413                 "Device object requires a _HID or _ADR in same scope");
414         }
415         break;
416 
417     case PARSEOP_EVENT:
418     case PARSEOP_MUTEX:
419     case PARSEOP_OPERATIONREGION:
420     case PARSEOP_POWERRESOURCE:
421     case PARSEOP_PROCESSOR:
422     case PARSEOP_THERMALZONE:
423 
424         /*
425          * The first operand is a name to be created in the namespace.
426          * Check against the reserved list.
427          */
428         i = ApCheckForPredefinedName (Op, Op->Asl.NameSeg);
429         if (i < ACPI_VALID_RESERVED_NAME_MAX)
430         {
431             AslError (ASL_ERROR, ASL_MSG_RESERVED_USE,
432                 Op, Op->Asl.ExternalName);
433         }
434         break;
435 
436     case PARSEOP_NAME:
437 
438         /* Typecheck any predefined names statically defined with Name() */
439 
440         ApCheckForPredefinedObject (Op, Op->Asl.NameSeg);
441 
442         /* Special typechecking for _HID */
443 
444         if (!strcmp (METHOD_NAME__HID, Op->Asl.NameSeg))
445         {
446             Next = Op->Asl.Child->Asl.Next;
447             AnCheckId (Next, ASL_TYPE_HID);
448         }
449 
450         /* Special typechecking for _CID */
451 
452         else if (!strcmp (METHOD_NAME__CID, Op->Asl.NameSeg))
453         {
454             Next = Op->Asl.Child->Asl.Next;
455 
456             if ((Next->Asl.ParseOpcode == PARSEOP_PACKAGE) ||
457                 (Next->Asl.ParseOpcode == PARSEOP_VAR_PACKAGE))
458             {
459                 Next = Next->Asl.Child;
460                 while (Next)
461                 {
462                     AnCheckId (Next, ASL_TYPE_CID);
463                     Next = Next->Asl.Next;
464                 }
465             }
466             else
467             {
468                 AnCheckId (Next, ASL_TYPE_CID);
469             }
470         }
471 
472         break;
473 
474     default:
475 
476         break;
477     }
478 
479     /* Check for named object creation within a non-serialized method */
480 
481     MtCheckNamedObjectInMethod (Op, MethodInfo);
482     return (AE_OK);
483 }
484 
485 
486 /*******************************************************************************
487  *
488  * FUNCTION:    MtCheckNamedObjectInMethod
489  *
490  * PARAMETERS:  Op                  - Current parser op
491  *              MethodInfo          - Info for method being parsed
492  *
493  * RETURN:      None
494  *
495  * DESCRIPTION: Detect if a non-serialized method is creating a named object,
496  *              which could possibly cause problems if two threads execute
497  *              the method concurrently. Emit a remark in this case.
498  *
499  ******************************************************************************/
500 
501 static void
502 MtCheckNamedObjectInMethod (
503     ACPI_PARSE_OBJECT       *Op,
504     ASL_METHOD_INFO         *MethodInfo)
505 {
506     const ACPI_OPCODE_INFO  *OpInfo;
507 
508 
509     /* We don't care about actual method declarations or scopes */
510 
511     if ((Op->Asl.AmlOpcode == AML_METHOD_OP) ||
512         (Op->Asl.AmlOpcode == AML_SCOPE_OP))
513     {
514         return;
515     }
516 
517     /* Determine if we are creating a named object */
518 
519     OpInfo = AcpiPsGetOpcodeInfo (Op->Asl.AmlOpcode);
520     if (OpInfo->Class == AML_CLASS_NAMED_OBJECT)
521     {
522         /*
523          * If we have a named object created within a non-serialized method,
524          * emit a remark that the method should be serialized.
525          *
526          * Reason: If a thread blocks within the method for any reason, and
527          * another thread enters the method, the method will fail because an
528          * attempt will be made to create the same object twice.
529          */
530         if (MethodInfo && !MethodInfo->ShouldBeSerialized)
531         {
532             AslError (ASL_REMARK, ASL_MSG_SERIALIZED_REQUIRED, MethodInfo->Op,
533                 "due to creation of named objects within");
534 
535             /* Emit message only ONCE per method */
536 
537             MethodInfo->ShouldBeSerialized = TRUE;
538         }
539     }
540 }
541 
542 
543 /*******************************************************************************
544  *
545  * FUNCTION:    MtMethodAnalysisWalkEnd
546  *
547  * PARAMETERS:  ASL_WALK_CALLBACK
548  *
549  * RETURN:      Status
550  *
551  * DESCRIPTION: Ascending callback for analysis walk. Complete method
552  *              return analysis.
553  *
554  ******************************************************************************/
555 
556 ACPI_STATUS
557 MtMethodAnalysisWalkEnd (
558     ACPI_PARSE_OBJECT       *Op,
559     UINT32                  Level,
560     void                    *Context)
561 {
562     ASL_ANALYSIS_WALK_INFO  *WalkInfo = (ASL_ANALYSIS_WALK_INFO *) Context;
563     ASL_METHOD_INFO         *MethodInfo = WalkInfo->MethodStack;
564 
565 
566     switch (Op->Asl.ParseOpcode)
567     {
568     case PARSEOP_METHOD:
569     case PARSEOP_RETURN:
570 
571         if (!MethodInfo)
572         {
573             printf ("No method info for method! [%s]\n", Op->Asl.Namepath);
574             AslError (ASL_ERROR, ASL_MSG_COMPILER_INTERNAL, Op,
575                 "No method info for this method");
576 
577             CmCleanupAndExit ();
578             return (AE_AML_INTERNAL);
579         }
580         break;
581 
582     default:
583 
584         break;
585     }
586 
587     switch (Op->Asl.ParseOpcode)
588     {
589     case PARSEOP_METHOD:
590 
591         WalkInfo->MethodStack = MethodInfo->Next;
592 
593         /*
594          * Check if there is no return statement at the end of the
595          * method AND we can actually get there -- i.e., the execution
596          * of the method can possibly terminate without a return statement.
597          */
598         if ((!AnLastStatementIsReturn (Op)) &&
599             (!(Op->Asl.CompileFlags & NODE_HAS_NO_EXIT)))
600         {
601             /*
602              * No return statement, and execution can possibly exit
603              * via this path. This is equivalent to Return ()
604              */
605             MethodInfo->NumReturnNoValue++;
606         }
607 
608         /*
609          * Check for case where some return statements have a return value
610          * and some do not. Exit without a return statement is a return with
611          * no value
612          */
613         if (MethodInfo->NumReturnNoValue &&
614             MethodInfo->NumReturnWithValue)
615         {
616             AslError (ASL_WARNING, ASL_MSG_RETURN_TYPES, Op,
617                 Op->Asl.ExternalName);
618         }
619 
620         /*
621          * If there are any RETURN() statements with no value, or there is a
622          * control path that allows the method to exit without a return value,
623          * we mark the method as a method that does not return a value. This
624          * knowledge can be used to check method invocations that expect a
625          * returned value.
626          */
627         if (MethodInfo->NumReturnNoValue)
628         {
629             if (MethodInfo->NumReturnWithValue)
630             {
631                 Op->Asl.CompileFlags |= NODE_METHOD_SOME_NO_RETVAL;
632             }
633             else
634             {
635                 Op->Asl.CompileFlags |= NODE_METHOD_NO_RETVAL;
636             }
637         }
638 
639         /*
640          * Check predefined method names for correct return behavior
641          * and correct number of arguments. Also, some special checks
642          * For GPE and _REG methods.
643          */
644         if (ApCheckForPredefinedMethod (Op, MethodInfo))
645         {
646             /* Special check for two names like _L01 and _E01 in same scope */
647 
648             ApCheckForGpeNameConflict (Op);
649 
650             /*
651              * Special check for _REG: Must have an operation region definition
652              * within the same scope!
653              */
654             ApCheckRegMethod (Op);
655         }
656 
657         ACPI_FREE (MethodInfo);
658         break;
659 
660     case PARSEOP_NAME:
661 
662          /* Special check for two names like _L01 and _E01 in same scope */
663 
664         ApCheckForGpeNameConflict (Op);
665         break;
666 
667     case PARSEOP_RETURN:
668 
669         /*
670          * If the parent is a predefined method name, attempt to typecheck
671          * the return value. Only static types can be validated.
672          */
673         ApCheckPredefinedReturnValue (Op, MethodInfo);
674 
675         /*
676          * The parent block does not "exit" and continue execution -- the
677          * method is terminated here with the Return() statement.
678          */
679         Op->Asl.Parent->Asl.CompileFlags |= NODE_HAS_NO_EXIT;
680 
681         /* Used in the "typing" pass later */
682 
683         Op->Asl.ParentMethod = MethodInfo->Op;
684 
685         /*
686          * If there is a peer node after the return statement, then this
687          * node is unreachable code -- i.e., it won't be executed because of
688          * the preceding Return() statement.
689          */
690         if (Op->Asl.Next)
691         {
692             AslError (ASL_WARNING, ASL_MSG_UNREACHABLE_CODE,
693                 Op->Asl.Next, NULL);
694         }
695         break;
696 
697     case PARSEOP_IF:
698 
699         if ((Op->Asl.CompileFlags & NODE_HAS_NO_EXIT) &&
700             (Op->Asl.Next) &&
701             (Op->Asl.Next->Asl.ParseOpcode == PARSEOP_ELSE))
702         {
703             /*
704              * This IF has a corresponding ELSE. The IF block has no exit,
705              * (it contains an unconditional Return)
706              * mark the ELSE block to remember this fact.
707              */
708             Op->Asl.Next->Asl.CompileFlags |= NODE_IF_HAS_NO_EXIT;
709         }
710         break;
711 
712     case PARSEOP_ELSE:
713 
714         if ((Op->Asl.CompileFlags & NODE_HAS_NO_EXIT) &&
715             (Op->Asl.CompileFlags & NODE_IF_HAS_NO_EXIT))
716         {
717             /*
718              * This ELSE block has no exit and the corresponding IF block
719              * has no exit either. Therefore, the parent node has no exit.
720              */
721             Op->Asl.Parent->Asl.CompileFlags |= NODE_HAS_NO_EXIT;
722         }
723         break;
724 
725 
726     default:
727 
728         if ((Op->Asl.CompileFlags & NODE_HAS_NO_EXIT) &&
729             (Op->Asl.Parent))
730         {
731             /* If this node has no exit, then the parent has no exit either */
732 
733             Op->Asl.Parent->Asl.CompileFlags |= NODE_HAS_NO_EXIT;
734         }
735         break;
736     }
737 
738     return (AE_OK);
739 }
740