xref: /freebsd/sys/contrib/dev/acpica/compiler/aslexternal.c (revision dca7f66f438fbc2ce4584a3863de83fdfccd2fd5)
1 /******************************************************************************
2  *
3  * Module Name: aslexternal - ASL External opcode compiler support
4  *
5  *****************************************************************************/
6 
7 /******************************************************************************
8  *
9  * 1. Copyright Notice
10  *
11  * Some or all of this work - Copyright (c) 1999 - 2020, Intel Corp.
12  * All rights reserved.
13  *
14  * 2. License
15  *
16  * 2.1. This is your license from Intel Corp. under its intellectual property
17  * rights. You may have additional license terms from the party that provided
18  * you this software, covering your right to use that party's intellectual
19  * property rights.
20  *
21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22  * copy of the source code appearing in this file ("Covered Code") an
23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24  * base code distributed originally by Intel ("Original Intel Code") to copy,
25  * make derivatives, distribute, use and display any portion of the Covered
26  * Code in any form, with the right to sublicense such rights; and
27  *
28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29  * license (with the right to sublicense), under only those claims of Intel
30  * patents that are infringed by the Original Intel Code, to make, use, sell,
31  * offer to sell, and import the Covered Code and derivative works thereof
32  * solely to the minimum extent necessary to exercise the above copyright
33  * license, and in no event shall the patent license extend to any additions
34  * to or modifications of the Original Intel Code. No other license or right
35  * is granted directly or by implication, estoppel or otherwise;
36  *
37  * The above copyright and patent license is granted only if the following
38  * conditions are met:
39  *
40  * 3. Conditions
41  *
42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43  * Redistribution of source code of any substantial portion of the Covered
44  * Code or modification with rights to further distribute source must include
45  * the above Copyright Notice, the above License, this list of Conditions,
46  * and the following Disclaimer and Export Compliance provision. In addition,
47  * Licensee must cause all Covered Code to which Licensee contributes to
48  * contain a file documenting the changes Licensee made to create that Covered
49  * Code and the date of any change. Licensee must include in that file the
50  * documentation of any changes made by any predecessor Licensee. Licensee
51  * must include a prominent statement that the modification is derived,
52  * directly or indirectly, from Original Intel Code.
53  *
54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55  * Redistribution of source code of any substantial portion of the Covered
56  * Code or modification without rights to further distribute source must
57  * include the following Disclaimer and Export Compliance provision in the
58  * documentation and/or other materials provided with distribution. In
59  * addition, Licensee may not authorize further sublicense of source of any
60  * portion of the Covered Code, and must include terms to the effect that the
61  * license from Licensee to its licensee is limited to the intellectual
62  * property embodied in the software Licensee provides to its licensee, and
63  * not to intellectual property embodied in modifications its licensee may
64  * make.
65  *
66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
67  * substantial portion of the Covered Code or modification must reproduce the
68  * above Copyright Notice, and the following Disclaimer and Export Compliance
69  * provision in the documentation and/or other materials provided with the
70  * distribution.
71  *
72  * 3.4. Intel retains all right, title, and interest in and to the Original
73  * Intel Code.
74  *
75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76  * Intel shall be used in advertising or otherwise to promote the sale, use or
77  * other dealings in products derived from or relating to the Covered Code
78  * without prior written authorization from Intel.
79  *
80  * 4. Disclaimer and Export Compliance
81  *
82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88  * PARTICULAR PURPOSE.
89  *
90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97  * LIMITED REMEDY.
98  *
99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
100  * software or system incorporating such software without first obtaining any
101  * required license or other approval from the U. S. Department of Commerce or
102  * any other agency or department of the United States Government. In the
103  * event Licensee exports any such software from the United States or
104  * re-exports any such software from a foreign destination, Licensee shall
105  * ensure that the distribution and export/re-export of the software is in
106  * compliance with all laws, regulations, orders, or other restrictions of the
107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108  * any of its subsidiaries will export/re-export any technical data, process,
109  * software, or service, directly or indirectly, to any country for which the
110  * United States government or any agency thereof requires an export license,
111  * other governmental approval, or letter of assurance, without first obtaining
112  * such license, approval or letter.
113  *
114  *****************************************************************************
115  *
116  * Alternatively, you may choose to be licensed under the terms of the
117  * following license:
118  *
119  * Redistribution and use in source and binary forms, with or without
120  * modification, are permitted provided that the following conditions
121  * are met:
122  * 1. Redistributions of source code must retain the above copyright
123  *    notice, this list of conditions, and the following disclaimer,
124  *    without modification.
125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
126  *    substantially similar to the "NO WARRANTY" disclaimer below
127  *    ("Disclaimer") and any redistribution must be conditioned upon
128  *    including a substantially similar Disclaimer requirement for further
129  *    binary redistribution.
130  * 3. Neither the names of the above-listed copyright holders nor the names
131  *    of any contributors may be used to endorse or promote products derived
132  *    from this software without specific prior written permission.
133  *
134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
145  *
146  * Alternatively, you may choose to be licensed under the terms of the
147  * GNU General Public License ("GPL") version 2 as published by the Free
148  * Software Foundation.
149  *
150  *****************************************************************************/
151 
152 #include <contrib/dev/acpica/compiler/aslcompiler.h>
153 #include "aslcompiler.y.h"
154 #include <contrib/dev/acpica/include/acparser.h>
155 #include <contrib/dev/acpica/include/amlcode.h>
156 #include <contrib/dev/acpica/include/acnamesp.h>
157 
158 
159 #define _COMPONENT          ACPI_COMPILER
160         ACPI_MODULE_NAME    ("aslexternal")
161 
162 
163 /* Local prototypes */
164 
165 static void
166 ExInsertArgCount (
167     ACPI_PARSE_OBJECT       *Op);
168 
169 static void
170 ExMoveExternals (
171     ACPI_PARSE_OBJECT       *DefinitionBlockOp);
172 
173 
174 /*******************************************************************************
175  *
176  * FUNCTION:    ExDoExternal
177  *
178  * PARAMETERS:  Op                  - Current Parse node
179  *
180  * RETURN:      None
181  *
182  * DESCRIPTION: Add an External() definition to the global list. This list
183  *              is used to generate External opcodes.
184  *
185  ******************************************************************************/
186 
187 void
188 ExDoExternal (
189     ACPI_PARSE_OBJECT       *Op)
190 {
191     ACPI_PARSE_OBJECT       *ListOp;
192     ACPI_PARSE_OBJECT       *Prev;
193     ACPI_PARSE_OBJECT       *Next;
194     ACPI_PARSE_OBJECT       *ArgCountOp;
195     ACPI_PARSE_OBJECT       *TypeOp;
196     ACPI_PARSE_OBJECT       *ExternTypeOp = Op->Asl.Child->Asl.Next;
197     UINT32                  ExternType;
198     UINT8                   ParamCount = ASL_EXTERNAL_METHOD_UNKNOWN_PARAMS;
199     UINT32                  ParamTypes[ACPI_METHOD_NUM_ARGS];
200 
201 
202     ExternType = AnMapObjTypeToBtype (ExternTypeOp);
203 
204     /*
205      * The parser allows optional parameter return types regardless of the
206      * type. Check object type keyword emit error if optional parameter/return
207      * types exist.
208      *
209      * Check the parameter return type
210      */
211     TypeOp = ExternTypeOp->Asl.Next;
212     if (TypeOp->Asl.Child)
213     {
214         /* Ignore the return type for now. */
215 
216         (void) MtProcessTypeOp (TypeOp->Asl.Child);
217         if (ExternType != ACPI_BTYPE_METHOD)
218         {
219             sprintf (AslGbl_MsgBuffer, "Found type [%s]", AcpiUtGetTypeName(ExternType));
220             AslError (ASL_ERROR, ASL_MSG_EXTERN_INVALID_RET_TYPE, TypeOp,
221                 AslGbl_MsgBuffer);
222         }
223     }
224 
225     /* Check the parameter types */
226 
227     TypeOp = TypeOp->Asl.Next;
228     if (TypeOp->Asl.Child)
229     {
230         ParamCount = MtProcessParameterTypeList (TypeOp->Asl.Child, ParamTypes);
231         if (ExternType != ACPI_BTYPE_METHOD)
232         {
233             sprintf (AslGbl_MsgBuffer, "Found type [%s]", AcpiUtGetTypeName(ExternType));
234             AslError (ASL_ERROR, ASL_MSG_EXTERN_INVALID_PARAM_TYPE, TypeOp,
235                 AslGbl_MsgBuffer);
236         }
237     }
238 
239     ArgCountOp = Op->Asl.Child->Asl.Next->Asl.Next;
240     ArgCountOp->Asl.AmlOpcode = AML_RAW_DATA_BYTE;
241     ArgCountOp->Asl.ParseOpcode = PARSEOP_BYTECONST;
242     ArgCountOp->Asl.Value.Integer = ParamCount;
243     UtSetParseOpName (ArgCountOp);
244 
245     /* Create new list node of arbitrary type */
246 
247     ListOp = TrAllocateOp (PARSEOP_DEFAULT_ARG);
248 
249     /* Store External node as child */
250 
251     ListOp->Asl.Child = Op;
252     ListOp->Asl.Next = NULL;
253 
254     if (AslGbl_ExternalsListHead)
255     {
256         /* Link new External to end of list */
257 
258         Prev = AslGbl_ExternalsListHead;
259         Next = Prev;
260         while (Next)
261         {
262             Prev = Next;
263             Next = Next->Asl.Next;
264         }
265 
266         Prev->Asl.Next = ListOp;
267     }
268     else
269     {
270         AslGbl_ExternalsListHead = ListOp;
271     }
272 }
273 
274 
275 /*******************************************************************************
276  *
277  * FUNCTION:    ExInsertArgCount
278  *
279  * PARAMETERS:  Op              - Op for a method invocation
280  *
281  * RETURN:      None
282  *
283  * DESCRIPTION: Obtain the number of arguments for a control method -- from
284  *              the actual invocation.
285  *
286  ******************************************************************************/
287 
288 static void
289 ExInsertArgCount (
290     ACPI_PARSE_OBJECT       *Op)
291 {
292     ACPI_PARSE_OBJECT       *Next;
293     ACPI_PARSE_OBJECT       *NameOp;
294     ACPI_PARSE_OBJECT       *Child;
295     ACPI_PARSE_OBJECT       *ArgCountOp;
296     char *                  ExternalName;
297     char *                  CallName;
298     UINT16                  ArgCount = 0;
299     ACPI_STATUS             Status;
300 
301 
302     CallName = AcpiNsGetNormalizedPathname (Op->Asl.Node, TRUE);
303 
304     Next = AslGbl_ExternalsListHead;
305     while (Next)
306     {
307         ArgCount = 0;
308 
309         /* Skip if External node already handled */
310 
311         if (Next->Asl.Child->Asl.CompileFlags & OP_VISITED)
312         {
313             Next = Next->Asl.Next;
314             continue;
315         }
316 
317         NameOp = Next->Asl.Child->Asl.Child;
318         ExternalName = AcpiNsGetNormalizedPathname (NameOp->Asl.Node, TRUE);
319 
320         if (strcmp (CallName, ExternalName))
321         {
322             ACPI_FREE (ExternalName);
323             Next = Next->Asl.Next;
324             continue;
325         }
326 
327         Next->Asl.Child->Asl.CompileFlags |= OP_VISITED;
328 
329         /*
330          * Since we will reposition Externals to the Root, set Namepath
331          * to the fully qualified name and recalculate the aml length
332          */
333         Status = UtInternalizeName (ExternalName,
334             &NameOp->Asl.Value.String);
335 
336         ACPI_FREE (ExternalName);
337         if (ACPI_FAILURE (Status))
338         {
339             AslError (ASL_ERROR, ASL_MSG_COMPILER_INTERNAL,
340                 NULL, "- Could not Internalize External");
341             break;
342         }
343 
344         NameOp->Asl.AmlLength = strlen (NameOp->Asl.Value.String);
345 
346         /* Get argument count */
347 
348         Child = Op->Asl.Child;
349         while (Child)
350         {
351             ArgCount++;
352             Child = Child->Asl.Next;
353         }
354 
355         /* Setup ArgCount operand */
356 
357         ArgCountOp = Next->Asl.Child->Asl.Child->Asl.Next->Asl.Next;
358         ArgCountOp->Asl.Value.Integer = ArgCount;
359         break;
360     }
361 
362     ACPI_FREE (CallName);
363 }
364 
365 
366 /*******************************************************************************
367  *
368  * FUNCTION:    ExAmlExternalWalkBegin
369  *
370  * PARAMETERS:  ASL_WALK_CALLBACK
371  *
372  * RETURN:      None
373  *
374  * DESCRIPTION: Parse tree walk to create external opcode list for methods.
375  *
376  ******************************************************************************/
377 
378 ACPI_STATUS
379 ExAmlExternalWalkBegin (
380     ACPI_PARSE_OBJECT       *Op,
381     UINT32                  Level,
382     void                    *Context)
383 {
384 
385     /* External list head saved in the definition block op */
386 
387     if (Op->Asl.ParseOpcode == PARSEOP_DEFINITION_BLOCK)
388     {
389         AslGbl_ExternalsListHead = Op->Asl.Value.Arg;
390     }
391 
392     if (!AslGbl_ExternalsListHead)
393     {
394         return (AE_OK);
395     }
396 
397     if (Op->Asl.ParseOpcode != PARSEOP_METHODCALL)
398     {
399         return (AE_OK);
400     }
401 
402     /*
403      * The NameOp child under an ExternalOp gets turned into PARSE_METHODCALL
404      * by XfNamespaceLocateBegin(). Ignore these.
405      */
406     if (Op->Asl.Parent &&
407         Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_EXTERNAL)
408     {
409         return (AE_OK);
410     }
411 
412     ExInsertArgCount (Op);
413     return (AE_OK);
414 }
415 
416 
417 /*******************************************************************************
418  *
419  * FUNCTION:    ExAmlExternalWalkEnd
420  *
421  * PARAMETERS:  ASL_WALK_CALLBACK
422  *
423  * RETURN:      None
424  *
425  * DESCRIPTION: Parse tree walk to create external opcode list for methods.
426  *              Here, we just want to catch the case where a definition block
427  *              has been completed. Then we move all of the externals into
428  *              a single block in the parse tree and thus the AML code.
429  *
430  ******************************************************************************/
431 
432 ACPI_STATUS
433 ExAmlExternalWalkEnd (
434     ACPI_PARSE_OBJECT       *Op,
435     UINT32                  Level,
436     void                    *Context)
437 {
438 
439     if (Op->Asl.ParseOpcode == PARSEOP_DEFINITION_BLOCK)
440     {
441         /*
442          * Process any existing external list. (Support for
443          * multiple definition blocks in a single file/compile)
444          */
445         ExMoveExternals (Op);
446         AslGbl_ExternalsListHead = NULL;
447     }
448 
449     return (AE_OK);
450 }
451 
452 
453 /*******************************************************************************
454  *
455  * FUNCTION:    ExMoveExternals
456  *
457  * PARAMETERS:  DefinitionBlockOp       - Op for current definition block
458  *
459  * RETURN:      None
460  *
461  * DESCRIPTION: Move all externals present in the source file into a single
462  *              block of AML code, surrounded by an "If (0)" to prevent
463  *              AML interpreters from attempting to execute the External
464  *              opcodes.
465  *
466  ******************************************************************************/
467 
468 static void
469 ExMoveExternals (
470     ACPI_PARSE_OBJECT       *DefinitionBlockOp)
471 {
472     ACPI_PARSE_OBJECT       *ParentOp;
473     ACPI_PARSE_OBJECT       *ExternalOp;
474     ACPI_PARSE_OBJECT       *PredicateOp;
475     ACPI_PARSE_OBJECT       *NextOp;
476     ACPI_PARSE_OBJECT       *Prev;
477     ACPI_PARSE_OBJECT       *Next;
478     char                    *ExternalName;
479     ACPI_OBJECT_TYPE        ObjType;
480     ACPI_STATUS             Status;
481     UINT32                  i;
482 
483 
484     if (!AslGbl_ExternalsListHead)
485     {
486         return;
487     }
488 
489     /* Remove the External nodes from the tree */
490 
491     NextOp = AslGbl_ExternalsListHead;
492     while (NextOp)
493     {
494         /*
495          * The External is stored in child pointer of each node in the
496          * list
497          */
498         ExternalOp = NextOp->Asl.Child;
499 
500         /* Get/set the fully qualified name */
501 
502         ExternalName = AcpiNsGetNormalizedPathname (ExternalOp->Asl.Node, TRUE);
503         ExternalOp->Asl.ExternalName = ExternalName;
504         ExternalOp->Asl.Namepath = ExternalName;
505 
506         /* Set line numbers (for listings, etc.) */
507 
508         ExternalOp->Asl.LineNumber = 0;
509         ExternalOp->Asl.LogicalLineNumber = 0;
510 
511         Next = ExternalOp->Asl.Child;
512         Next->Asl.LineNumber = 0;
513         Next->Asl.LogicalLineNumber = 0;
514 
515         if (Next->Asl.ParseOpcode == PARSEOP_NAMESEG)
516         {
517             Next->Asl.ParseOpcode = PARSEOP_NAMESTRING;
518         }
519 
520         Next->Asl.ExternalName = ExternalName;
521         Status = UtInternalizeName (ExternalName, &Next->Asl.Value.String);
522         if (ACPI_FAILURE (Status))
523         {
524             AslError (ASL_ERROR, ASL_MSG_COMPILER_INTERNAL,
525                 Next, "Could not internalize namestring");
526             return;
527         }
528 
529         Next->Asl.AmlLength = strlen (Next->Asl.Value.String);
530 
531         Next = Next->Asl.Next;
532         Next->Asl.LineNumber = 0;
533         Next->Asl.LogicalLineNumber = 0;
534 
535         Next = Next->Asl.Next;
536         Next->Asl.LineNumber = 0;
537         Next->Asl.LogicalLineNumber = 0;
538 
539         Next = Next->Asl.Next;
540         Next->Asl.LineNumber = 0;
541         Next->Asl.LogicalLineNumber = 0;
542 
543         ParentOp = ExternalOp->Asl.Parent;
544         Prev = Next = ParentOp->Asl.Child;
545 
546         /* Now find the External node's position in parse tree */
547 
548         while (Next != ExternalOp)
549         {
550             Prev = Next;
551             Next = Next->Asl.Next;
552         }
553 
554         /* Remove the External from the parse tree */
555 
556         if (Prev == ExternalOp)
557         {
558             /* External was the first child node */
559 
560             ParentOp->Asl.Child = ExternalOp->Asl.Next;
561         }
562 
563         Prev->Asl.Next = ExternalOp->Asl.Next;
564         ExternalOp->Asl.Next = NULL;
565         ExternalOp->Asl.Parent = AslGbl_ExternalsListHead;
566 
567         /* Point the External to the next in the list */
568 
569         if (NextOp->Asl.Next)
570         {
571             ExternalOp->Asl.Next = NextOp->Asl.Next->Asl.Child;
572         }
573 
574         NextOp = NextOp->Asl.Next;
575     }
576 
577     /*
578      * Loop again to remove MethodObj Externals for which
579      * a MethodCall was not found (dead external reference)
580      */
581     Prev = AslGbl_ExternalsListHead->Asl.Child;
582     Next = Prev;
583     while (Next)
584     {
585         ObjType = (ACPI_OBJECT_TYPE)
586             Next->Asl.Child->Asl.Next->Asl.Value.Integer;
587 
588         if (ObjType == ACPI_TYPE_METHOD &&
589             !(Next->Asl.CompileFlags & OP_VISITED))
590         {
591             if (Next == Prev)
592             {
593                 AslGbl_ExternalsListHead->Asl.Child = Next->Asl.Next;
594                 Next->Asl.Next = NULL;
595                 Prev = AslGbl_ExternalsListHead->Asl.Child;
596                 Next = Prev;
597                 continue;
598             }
599             else
600             {
601                 Prev->Asl.Next = Next->Asl.Next;
602                 Next->Asl.Next = NULL;
603                 Next = Prev->Asl.Next;
604                 continue;
605             }
606         }
607 
608         Prev = Next;
609         Next = Next->Asl.Next;
610     }
611 
612     /* If list is now empty, don't bother to make If (0) block */
613 
614     if (!AslGbl_ExternalsListHead->Asl.Child)
615     {
616         return;
617     }
618 
619     /* Convert Gbl_ExternalsListHead parent to If(). */
620 
621     AslGbl_ExternalsListHead->Asl.ParseOpcode = PARSEOP_IF;
622     AslGbl_ExternalsListHead->Asl.AmlOpcode = AML_IF_OP;
623     AslGbl_ExternalsListHead->Asl.CompileFlags = OP_AML_PACKAGE;
624     UtSetParseOpName (AslGbl_ExternalsListHead);
625 
626     /* Create a Zero op for the If predicate */
627 
628     PredicateOp = TrAllocateOp (PARSEOP_ZERO);
629     PredicateOp->Asl.AmlOpcode = AML_ZERO_OP;
630 
631     PredicateOp->Asl.Parent = AslGbl_ExternalsListHead;
632     PredicateOp->Asl.Child = NULL;
633     PredicateOp->Asl.Next = AslGbl_ExternalsListHead->Asl.Child;
634     AslGbl_ExternalsListHead->Asl.Child = PredicateOp;
635 
636     /* Set line numbers (for listings, etc.) */
637 
638     AslGbl_ExternalsListHead->Asl.LineNumber = 0;
639     AslGbl_ExternalsListHead->Asl.LogicalLineNumber = 0;
640 
641     PredicateOp->Asl.LineNumber = 0;
642     PredicateOp->Asl.LogicalLineNumber = 0;
643 
644     /* Insert block back in the list */
645 
646     Prev = DefinitionBlockOp->Asl.Child;
647     Next = Prev;
648 
649     /* Find last default arg */
650 
651     for (i = 0; i < 6; i++)
652     {
653         Prev = Next;
654         Next = Prev->Asl.Next;
655     }
656 
657     if (Next)
658     {
659         /* Definition Block is not empty */
660 
661         AslGbl_ExternalsListHead->Asl.Next = Next;
662     }
663     else
664     {
665         /* Definition Block is empty. */
666 
667         AslGbl_ExternalsListHead->Asl.Next = NULL;
668     }
669 
670     Prev->Asl.Next = AslGbl_ExternalsListHead;
671     AslGbl_ExternalsListHead->Asl.Parent = Prev->Asl.Parent;
672 }
673