xref: /freebsd/sys/contrib/dev/acpica/compiler/aslfold.c (revision 4f52dfbb8d6c4d446500c5b097e3806ec219fbd4)
1 /******************************************************************************
2  *
3  * Module Name: aslfold - Constant folding
4  *
5  *****************************************************************************/
6 
7 /******************************************************************************
8  *
9  * 1. Copyright Notice
10  *
11  * Some or all of this work - Copyright (c) 1999 - 2018, 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/amlcode.h>
155 
156 #include <contrib/dev/acpica/include/acdispat.h>
157 #include <contrib/dev/acpica/include/acparser.h>
158 
159 #define _COMPONENT          ACPI_COMPILER
160         ACPI_MODULE_NAME    ("aslfold")
161 
162 /* Local prototypes */
163 
164 static ACPI_STATUS
165 OpcAmlEvaluationWalk1 (
166     ACPI_PARSE_OBJECT       *Op,
167     UINT32                  Level,
168     void                    *Context);
169 
170 static ACPI_STATUS
171 OpcAmlEvaluationWalk2 (
172     ACPI_PARSE_OBJECT       *Op,
173     UINT32                  Level,
174     void                    *Context);
175 
176 static ACPI_STATUS
177 OpcAmlCheckForConstant (
178     ACPI_PARSE_OBJECT       *Op,
179     UINT32                  Level,
180     void                    *Context);
181 
182 static void
183 OpcUpdateIntegerNode (
184     ACPI_PARSE_OBJECT       *Op,
185     UINT64                  Value);
186 
187 static ACPI_STATUS
188 TrTransformToStoreOp (
189     ACPI_PARSE_OBJECT       *Op,
190     ACPI_WALK_STATE         *WalkState);
191 
192 static ACPI_STATUS
193 TrSimpleConstantReduction (
194     ACPI_PARSE_OBJECT       *Op,
195     ACPI_WALK_STATE         *WalkState);
196 
197 static void
198 TrInstallReducedConstant (
199     ACPI_PARSE_OBJECT       *Op,
200     ACPI_OPERAND_OBJECT     *ObjDesc);
201 
202 
203 /*******************************************************************************
204  *
205  * FUNCTION:    OpcAmlConstantWalk
206  *
207  * PARAMETERS:  ASL_WALK_CALLBACK
208  *
209  * RETURN:      Status
210  *
211  * DESCRIPTION: Reduce an Op and its subtree to a constant if possible.
212  *              Called during ascent of the parse tree.
213  *
214  ******************************************************************************/
215 
216 ACPI_STATUS
217 OpcAmlConstantWalk (
218     ACPI_PARSE_OBJECT       *Op,
219     UINT32                  Level,
220     void                    *Context)
221 {
222     ACPI_WALK_STATE         *WalkState;
223     ACPI_STATUS             Status = AE_OK;
224 
225 
226     if (Op->Asl.CompileFlags == 0)
227     {
228         return (AE_OK);
229     }
230 
231     /*
232      * Only interested in subtrees that could possibly contain
233      * expressions that can be evaluated at this time
234      */
235     if ((!(Op->Asl.CompileFlags & OP_COMPILE_TIME_CONST)) ||
236           (Op->Asl.CompileFlags & OP_IS_TARGET))
237     {
238         return (AE_OK);
239     }
240 
241     /* Create a new walk state */
242 
243     WalkState = AcpiDsCreateWalkState (0, NULL, NULL, NULL);
244     if (!WalkState)
245     {
246         return (AE_NO_MEMORY);
247     }
248 
249     WalkState->NextOp = NULL;
250     WalkState->Params = NULL;
251 
252     /*
253      * Examine the entire subtree -- all nodes must be constants
254      * or type 3/4/5 opcodes
255      */
256     Status = TrWalkParseTree (Op, ASL_WALK_VISIT_DOWNWARD,
257         OpcAmlCheckForConstant, NULL, WalkState);
258 
259     /*
260      * Did we find an entire subtree that contains all constants
261      * and type 3/4/5 opcodes?
262      */
263     switch (Status)
264     {
265     case AE_OK:
266 
267         /* Simple case, like Add(3,4) -> 7 */
268 
269         Status = TrSimpleConstantReduction (Op, WalkState);
270         break;
271 
272     case AE_CTRL_RETURN_VALUE:
273 
274         /* More complex case, like Add(3,4,Local0) -> Store(7,Local0) */
275 
276         Status = TrTransformToStoreOp (Op, WalkState);
277         break;
278 
279     case AE_TYPE:
280 
281         AcpiDsDeleteWalkState (WalkState);
282         return (AE_OK);
283 
284     default:
285         AcpiDsDeleteWalkState (WalkState);
286         break;
287     }
288 
289     if (ACPI_FAILURE (Status))
290     {
291         DbgPrint (ASL_PARSE_OUTPUT, "Cannot resolve, %s\n",
292             AcpiFormatException (Status));
293 
294         /* We could not resolve the subtree for some reason */
295 
296         AslError (ASL_ERROR, ASL_MSG_CONSTANT_EVALUATION, Op,
297             (char *) AcpiFormatException (Status));
298 
299         /* Set the subtree value to ZERO anyway. Eliminates further errors */
300 
301         OpcUpdateIntegerNode (Op, 0);
302     }
303 
304     return (AE_OK);
305 }
306 
307 
308 /*******************************************************************************
309  *
310  * FUNCTION:    OpcAmlCheckForConstant
311  *
312  * PARAMETERS:  ASL_WALK_CALLBACK
313  *
314  * RETURN:      Status
315  *
316  * DESCRIPTION: Check one Op for a reducible type 3/4/5 AML opcode.
317  *              This is performed via an upward walk of the parse subtree.
318  *
319  ******************************************************************************/
320 
321 static ACPI_STATUS
322 OpcAmlCheckForConstant (
323     ACPI_PARSE_OBJECT       *Op,
324     UINT32                  Level,
325     void                    *Context)
326 {
327     ACPI_WALK_STATE         *WalkState = Context;
328     ACPI_STATUS             Status = AE_OK;
329     ACPI_PARSE_OBJECT       *NextOp;
330     const ACPI_OPCODE_INFO  *OpInfo;
331 
332 
333     WalkState->Op = Op;
334     WalkState->Opcode = Op->Common.AmlOpcode;
335     WalkState->OpInfo = AcpiPsGetOpcodeInfo (Op->Common.AmlOpcode);
336 
337     DbgPrint (ASL_PARSE_OUTPUT, "[%.4d] Opcode: %12.12s ",
338         Op->Asl.LogicalLineNumber, Op->Asl.ParseOpName);
339 
340     /*
341      * These opcodes do not appear in the OpcodeInfo table, but
342      * they represent constants, so abort the constant walk now.
343      */
344     if ((WalkState->Opcode == AML_RAW_DATA_BYTE) ||
345         (WalkState->Opcode == AML_RAW_DATA_WORD) ||
346         (WalkState->Opcode == AML_RAW_DATA_DWORD) ||
347         (WalkState->Opcode == AML_RAW_DATA_QWORD))
348     {
349         DbgPrint (ASL_PARSE_OUTPUT, "RAW DATA");
350         Status = AE_TYPE;
351         goto CleanupAndExit;
352     }
353 
354     /*
355      * Search upwards for a possible Name() operator. This is done
356      * because a type 3/4/5 opcode within a Name() expression
357      * MUST be reduced to a simple constant.
358      */
359     NextOp = Op->Asl.Parent;
360     while (NextOp)
361     {
362         /* Finished if we find a Name() opcode */
363 
364         if (NextOp->Asl.AmlOpcode == AML_NAME_OP)
365         {
366             break;
367         }
368 
369         /*
370          * Any "deferred" opcodes contain one or more TermArg parameters,
371          * and thus are not required to be folded to constants at compile
372          * time. This affects things like Buffer() and Package() objects.
373          * We just ignore them here. However, any sub-expressions can and
374          * will still be typechecked. Note: These are called the
375          * "deferred" opcodes in the AML interpreter.
376          */
377         OpInfo = AcpiPsGetOpcodeInfo (NextOp->Common.AmlOpcode);
378         if (OpInfo->Flags & AML_DEFER)
379         {
380             NextOp = NULL;
381             break;
382         }
383 
384         NextOp = NextOp->Asl.Parent;
385     }
386 
387     /* Type 3/4/5 opcodes have the AML_CONSTANT flag set */
388 
389     if (!(WalkState->OpInfo->Flags & AML_CONSTANT))
390     {
391         /*
392          * From the ACPI specification:
393          *
394          * "The Type 3/4/5 opcodes return a value and can be used in an
395          * expression that evaluates to a constant. These opcodes may be
396          * evaluated at ASL compile-time. To ensure that these opcodes
397          * will evaluate to a constant, the following rules apply: The
398          * term cannot have a destination (target) operand, and must have
399          * either a Type3Opcode, Type4Opcode, Type5Opcode, ConstExprTerm,
400          * Integer, BufferTerm, Package, or String for all arguments."
401          */
402 
403         /*
404          * The value (second) operand for the Name() operator MUST
405          * reduce to a single constant, as per the ACPI specification
406          * (the operand is a DataObject). This also implies that there
407          * can be no target operand. Name() is the only ASL operator
408          * with a "DataObject" as an operand and is thus special-
409          * cased here.
410          */
411         if (NextOp) /* Inspect a Name() operator */
412         {
413             /* Error if there is a target operand */
414 
415             if (Op->Asl.CompileFlags & OP_IS_TARGET)
416             {
417                 AslError (ASL_ERROR, ASL_MSG_INVALID_TARGET, Op, NULL);
418                 Status = AE_TYPE;
419             }
420 
421             /* Error if expression cannot be reduced (folded) */
422 
423             if (!(NextOp->Asl.CompileFlags & OP_COULD_NOT_REDUCE))
424             {
425                 /* Ensure only one error message per statement */
426 
427                 NextOp->Asl.CompileFlags |= OP_COULD_NOT_REDUCE;
428                 DbgPrint (ASL_PARSE_OUTPUT,
429                     "**** Could not reduce operands for NAME opcode ****\n");
430 
431                 AslError (ASL_ERROR, ASL_MSG_CONSTANT_REQUIRED, Op,
432                     "Constant is required for Name operator");
433                 Status = AE_TYPE;
434             }
435         }
436 
437         if (ACPI_FAILURE (Status))
438         {
439             goto CleanupAndExit;
440         }
441 
442         /* This is not a 3/4/5 opcode, but maybe can convert to STORE */
443 
444         if (Op->Asl.CompileFlags & OP_IS_TARGET)
445         {
446             DbgPrint (ASL_PARSE_OUTPUT,
447                 "**** Valid Target, transform to Store or CopyObject ****\n");
448             return (AE_CTRL_RETURN_VALUE);
449         }
450 
451         /* Expression cannot be reduced */
452 
453         DbgPrint (ASL_PARSE_OUTPUT,
454             "**** Not a Type 3/4/5 opcode or cannot reduce/fold (%s) ****\n",
455              Op->Asl.ParseOpName);
456 
457         Status = AE_TYPE;
458         goto CleanupAndExit;
459     }
460 
461     /*
462      * TBD: Ignore buffer constants for now. The problem is that these
463      * constants have been transformed into RAW_DATA at this point, from
464      * the parse tree transform process which currently happens before
465      * the constant folding process. We may need to defer this transform
466      * for buffer until after the constant folding.
467      */
468     if (WalkState->Opcode == AML_BUFFER_OP)
469     {
470         DbgPrint (ASL_PARSE_OUTPUT,
471             "\nBuffer constant reduction is currently not supported\n");
472 
473         if (NextOp) /* Found a Name() operator, error */
474         {
475             AslError (ASL_ERROR, ASL_MSG_UNSUPPORTED, Op,
476                 "Buffer expression cannot be reduced");
477         }
478 
479         Status = AE_TYPE;
480         goto CleanupAndExit;
481     }
482 
483     /* Debug output */
484 
485     DbgPrint (ASL_PARSE_OUTPUT, "TYPE_345");
486 
487     if (Op->Asl.CompileFlags & OP_IS_TARGET)
488     {
489         if (Op->Asl.ParseOpcode == PARSEOP_ZERO)
490         {
491             DbgPrint (ASL_PARSE_OUTPUT, "%-16s", " NULL TARGET");
492         }
493         else
494         {
495             DbgPrint (ASL_PARSE_OUTPUT, "%-16s", " VALID TARGET");
496         }
497     }
498 
499     if (Op->Asl.CompileFlags & OP_IS_TERM_ARG)
500     {
501         DbgPrint (ASL_PARSE_OUTPUT, "%-16s", " TERMARG");
502     }
503 
504 CleanupAndExit:
505 
506     /* Dump the node compile flags also */
507 
508     TrPrintOpFlags (Op->Asl.CompileFlags, ASL_PARSE_OUTPUT);
509     DbgPrint (ASL_PARSE_OUTPUT, "\n");
510     return (Status);
511 }
512 
513 
514 /*******************************************************************************
515  *
516  * FUNCTION:    TrSimpleConstantReduction
517  *
518  * PARAMETERS:  Op                  - Parent operator to be transformed
519  *              WalkState           - Current walk state
520  *
521  * RETURN:      Status
522  *
523  * DESCRIPTION: Reduce an entire AML operation to a single constant. The
524  *              operation must not have a target operand.
525  *
526  *              Add (32,64) --> 96
527  *
528  ******************************************************************************/
529 
530 static ACPI_STATUS
531 TrSimpleConstantReduction (
532     ACPI_PARSE_OBJECT       *Op,
533     ACPI_WALK_STATE         *WalkState)
534 {
535     ACPI_PARSE_OBJECT       *RootOp;
536     ACPI_PARSE_OBJECT       *OriginalParentOp;
537     ACPI_OPERAND_OBJECT     *ObjDesc;
538     ACPI_STATUS             Status;
539 
540 
541     DbgPrint (ASL_PARSE_OUTPUT,
542         "Simple subtree constant reduction, operator to constant\n");
543 
544     /* Allocate a new temporary root for this subtree */
545 
546     RootOp = TrAllocateOp (PARSEOP_INTEGER);
547     if (!RootOp)
548     {
549         return (AE_NO_MEMORY);
550     }
551 
552     RootOp->Common.AmlOpcode = AML_INT_EVAL_SUBTREE_OP;
553 
554     OriginalParentOp = Op->Common.Parent;
555     Op->Common.Parent = RootOp;
556 
557     /* Hand off the subtree to the AML interpreter */
558 
559     WalkState->CallerReturnDesc = &ObjDesc;
560 
561     Status = TrWalkParseTree (Op, ASL_WALK_VISIT_TWICE,
562         OpcAmlEvaluationWalk1, OpcAmlEvaluationWalk2, WalkState);
563 
564     /* Restore original parse tree */
565 
566     Op->Common.Parent = OriginalParentOp;
567 
568     if (ACPI_FAILURE (Status))
569     {
570         DbgPrint (ASL_PARSE_OUTPUT,
571             "Constant Subtree evaluation(1), %s\n",
572             AcpiFormatException (Status));
573         return (Status);
574     }
575 
576     /* Get the final result */
577 
578     Status = AcpiDsResultPop (&ObjDesc, WalkState);
579     if (ACPI_FAILURE (Status))
580     {
581         DbgPrint (ASL_PARSE_OUTPUT,
582             "Constant Subtree evaluation(2), %s\n",
583             AcpiFormatException (Status));
584         return (Status);
585     }
586 
587     /* Disconnect any existing children, install new constant */
588 
589     Op->Asl.Child = NULL;
590     TrInstallReducedConstant (Op, ObjDesc);
591 
592     UtSetParseOpName (Op);
593     return (AE_OK);
594 }
595 
596 
597 /*******************************************************************************
598  *
599  * FUNCTION:    TrTransformToStoreOp
600  *
601  * PARAMETERS:  Op                  - Parent operator to be transformed
602  *              WalkState           - Current walk state
603  *
604  * RETURN:      Status
605  *
606  * DESCRIPTION: Transforms a single AML operation with a constant and target
607  *              to a simple store operation:
608  *
609  *              Add (32,64,DATA) --> Store (96,DATA)
610  *
611  ******************************************************************************/
612 
613 static ACPI_STATUS
614 TrTransformToStoreOp (
615     ACPI_PARSE_OBJECT       *Op,
616     ACPI_WALK_STATE         *WalkState)
617 {
618     ACPI_PARSE_OBJECT       *OriginalTarget;
619     ACPI_PARSE_OBJECT       *NewTarget;
620     ACPI_PARSE_OBJECT       *Child1;
621     ACPI_PARSE_OBJECT       *Child2;
622     ACPI_OPERAND_OBJECT     *ObjDesc;
623     ACPI_PARSE_OBJECT       *NewParent;
624     ACPI_PARSE_OBJECT       *OriginalParent;
625     ACPI_STATUS             Status;
626     UINT16                  NewParseOpcode;
627     UINT16                  NewAmlOpcode;
628 
629 
630     /* Extract the operands */
631 
632     Child1 = Op->Asl.Child;
633     Child2 = Child1->Asl.Next;
634 
635     /*
636      * Special case for DIVIDE -- it has two targets. The first
637      * is for the remainder and if present, we will not attempt
638      * to reduce the expression.
639      */
640     if (Op->Asl.ParseOpcode == PARSEOP_DIVIDE)
641     {
642         Child2 = Child2->Asl.Next;
643         if (Child2->Asl.ParseOpcode != PARSEOP_ZERO)
644         {
645             DbgPrint (ASL_PARSE_OUTPUT,
646                 "Cannot reduce DIVIDE - has two targets\n\n");
647             return (AE_OK);
648         }
649     }
650 
651     switch (Op->Asl.ParseOpcode)
652     {
653     /*
654      * Folding of the explicit conversion opcodes must use CopyObject
655      * instead of Store. This can change the object type of the target
656      * operand, as per the ACPI specification:
657      *
658      * "If the ASL operator is one of the explicit conversion operators
659      * (ToString, ToInteger, etc., and the CopyObject operator), no
660      * [implicit] conversion is performed. (In other words, the result
661      * object is stored directly to the target and completely overwrites
662      * any existing object already stored at the target)"
663      */
664     case PARSEOP_TOINTEGER:
665     case PARSEOP_TOSTRING:
666     case PARSEOP_TOBUFFER:
667     case PARSEOP_TODECIMALSTRING:
668     case PARSEOP_TOHEXSTRING:
669     case PARSEOP_TOBCD:
670     case PARSEOP_FROMBCD:
671 
672         NewParseOpcode = PARSEOP_COPYOBJECT;
673         NewAmlOpcode = AML_COPY_OBJECT_OP;
674 
675         DbgPrint (ASL_PARSE_OUTPUT,
676             "Reduction/Transform to CopyObjectOp: CopyObject(%s, %s)\n",
677             Child1->Asl.ParseOpName, Child2->Asl.ParseOpName);
678         break;
679 
680     default:
681 
682         NewParseOpcode = PARSEOP_STORE;
683         NewAmlOpcode = AML_STORE_OP;
684 
685         DbgPrint (ASL_PARSE_OUTPUT,
686             "Reduction/Transform to StoreOp: Store(%s, %s)\n",
687             Child1->Asl.ParseOpName, Child2->Asl.ParseOpName);
688         break;
689     }
690 
691     /*
692      * Create a NULL (zero) target so that we can use the
693      * interpreter to evaluate the expression.
694      */
695     NewTarget = TrCreateNullTargetOp ();
696     NewTarget->Common.AmlOpcode = AML_INT_NAMEPATH_OP;
697 
698     /* Handle one-operand cases (NOT, TOBCD, etc.) */
699 
700     if (!Child2->Asl.Next)
701     {
702         Child2 = Child1;
703     }
704 
705     /* Link in new NULL target as the last operand */
706 
707     OriginalTarget = Child2->Asl.Next;
708     Child2->Asl.Next = NewTarget;
709     NewTarget->Asl.Parent = OriginalTarget->Asl.Parent;
710 
711     NewParent = TrAllocateOp (PARSEOP_INTEGER);
712     NewParent->Common.AmlOpcode = AML_INT_EVAL_SUBTREE_OP;
713 
714     OriginalParent = Op->Common.Parent;
715     Op->Common.Parent = NewParent;
716 
717     /* Hand off the subtree to the AML interpreter */
718 
719     WalkState->CallerReturnDesc = &ObjDesc;
720 
721     Status = TrWalkParseTree (Op, ASL_WALK_VISIT_TWICE,
722         OpcAmlEvaluationWalk1, OpcAmlEvaluationWalk2, WalkState);
723     if (ACPI_FAILURE (Status))
724     {
725         DbgPrint (ASL_PARSE_OUTPUT,
726             "Constant Subtree evaluation(3), %s\n",
727             AcpiFormatException (Status));
728         goto EvalError;
729     }
730 
731     /* Get the final result */
732 
733     Status = AcpiDsResultPop (&ObjDesc, WalkState);
734     if (ACPI_FAILURE (Status))
735     {
736         DbgPrint (ASL_PARSE_OUTPUT,
737             "Constant Subtree evaluation(4), %s\n",
738             AcpiFormatException (Status));
739         goto EvalError;
740     }
741 
742     /* Truncate any subtree expressions, they have been evaluated */
743 
744     Child1->Asl.Child = NULL;
745 
746     /* Folded constant is in ObjDesc, store into Child1 */
747 
748     TrInstallReducedConstant (Child1, ObjDesc);
749 
750     /* Convert operator to STORE or COPYOBJECT */
751 
752     Op->Asl.ParseOpcode = NewParseOpcode;
753     Op->Asl.AmlOpcode = NewAmlOpcode;
754     UtSetParseOpName (Op);
755     Op->Common.Parent = OriginalParent;
756 
757     /* First child is the folded constant */
758 
759     /* Second child will be the target */
760 
761     Child1->Asl.Next = OriginalTarget;
762     return (AE_OK);
763 
764 
765 EvalError:
766 
767     /* Restore original links */
768 
769     Op->Common.Parent = OriginalParent;
770     Child2->Asl.Next = OriginalTarget;
771     return (Status);
772 }
773 
774 
775 /*******************************************************************************
776  *
777  * FUNCTION:    TrInstallReducedConstant
778  *
779  * PARAMETERS:  Op                  - Parent operator to be transformed
780  *              ObjDesc             - Reduced constant to be installed
781  *
782  * RETURN:      None
783  *
784  * DESCRIPTION: Transform the original operator to a simple constant.
785  *              Handles Integers, Strings, and Buffers.
786  *
787  ******************************************************************************/
788 
789 static void
790 TrInstallReducedConstant (
791     ACPI_PARSE_OBJECT       *Op,
792     ACPI_OPERAND_OBJECT     *ObjDesc)
793 {
794     ACPI_PARSE_OBJECT       *LengthOp;
795     ACPI_PARSE_OBJECT       *DataOp;
796 
797 
798     TotalFolds++;
799     AslError (ASL_OPTIMIZATION, ASL_MSG_CONSTANT_FOLDED, Op,
800         Op->Asl.ParseOpName);
801 
802     /*
803      * Because we know we executed type 3/4/5 opcodes above, we know that
804      * the result must be either an Integer, String, or Buffer.
805      */
806     switch (ObjDesc->Common.Type)
807     {
808     case ACPI_TYPE_INTEGER:
809 
810         OpcUpdateIntegerNode (Op, ObjDesc->Integer.Value);
811 
812         DbgPrint (ASL_PARSE_OUTPUT,
813             "Constant expression reduced to (%s) %8.8X%8.8X\n\n",
814             Op->Asl.ParseOpName,
815             ACPI_FORMAT_UINT64 (Op->Common.Value.Integer));
816         break;
817 
818     case ACPI_TYPE_STRING:
819 
820         Op->Asl.ParseOpcode = PARSEOP_STRING_LITERAL;
821         Op->Common.AmlOpcode = AML_STRING_OP;
822         Op->Asl.AmlLength = strlen (ObjDesc->String.Pointer) + 1;
823         Op->Common.Value.String = ObjDesc->String.Pointer;
824 
825         DbgPrint (ASL_PARSE_OUTPUT,
826             "Constant expression reduced to (STRING) %s\n\n",
827             Op->Common.Value.String);
828         break;
829 
830     case ACPI_TYPE_BUFFER:
831         /*
832          * Create a new parse subtree of the form:
833          *
834          * BUFFER (Buffer AML opcode)
835          *    INTEGER (Buffer length in bytes)
836          *    RAW_DATA (Buffer byte data)
837          */
838         Op->Asl.ParseOpcode = PARSEOP_BUFFER;
839         Op->Common.AmlOpcode = AML_BUFFER_OP;
840         Op->Asl.CompileFlags = OP_AML_PACKAGE;
841         UtSetParseOpName (Op);
842 
843         /* Child node is the buffer length */
844 
845         LengthOp = TrAllocateOp (PARSEOP_INTEGER);
846 
847         LengthOp->Asl.AmlOpcode = AML_DWORD_OP;
848         LengthOp->Asl.Value.Integer = ObjDesc->Buffer.Length;
849         LengthOp->Asl.Parent = Op;
850         (void) OpcSetOptimalIntegerSize (LengthOp);
851 
852         Op->Asl.Child = LengthOp;
853 
854         /* Next child is the raw buffer data */
855 
856         DataOp = TrAllocateOp (PARSEOP_RAW_DATA);
857         DataOp->Asl.AmlOpcode = AML_RAW_DATA_BUFFER;
858         DataOp->Asl.AmlLength = ObjDesc->Buffer.Length;
859         DataOp->Asl.Value.String = (char *) ObjDesc->Buffer.Pointer;
860         DataOp->Asl.Parent = Op;
861 
862         LengthOp->Asl.Next = DataOp;
863 
864         DbgPrint (ASL_PARSE_OUTPUT,
865             "Constant expression reduced to (BUFFER) length %X\n\n",
866             ObjDesc->Buffer.Length);
867         break;
868 
869     default:
870         break;
871     }
872 }
873 
874 
875 /*******************************************************************************
876  *
877  * FUNCTION:    OpcUpdateIntegerNode
878  *
879  * PARAMETERS:  Op                  - Current parse object
880  *              Value               - Value for the integer op
881  *
882  * RETURN:      None
883  *
884  * DESCRIPTION: Update node to the correct Integer type and value
885  *
886  ******************************************************************************/
887 
888 static void
889 OpcUpdateIntegerNode (
890     ACPI_PARSE_OBJECT       *Op,
891     UINT64                  Value)
892 {
893 
894     Op->Common.Value.Integer = Value;
895 
896     /*
897      * The AmlLength is used by the parser to indicate a constant,
898      * (if non-zero). Length is either (1/2/4/8)
899      */
900     switch (Op->Asl.AmlLength)
901     {
902     case 1:
903 
904         TrSetOpIntegerValue (PARSEOP_BYTECONST, Op);
905         Op->Asl.AmlOpcode = AML_RAW_DATA_BYTE;
906         break;
907 
908     case 2:
909 
910         TrSetOpIntegerValue (PARSEOP_WORDCONST, Op);
911         Op->Asl.AmlOpcode = AML_RAW_DATA_WORD;
912         break;
913 
914     case 4:
915 
916         TrSetOpIntegerValue (PARSEOP_DWORDCONST, Op);
917         Op->Asl.AmlOpcode = AML_RAW_DATA_DWORD;
918         break;
919 
920     case 8:
921 
922         TrSetOpIntegerValue (PARSEOP_QWORDCONST, Op);
923         Op->Asl.AmlOpcode = AML_RAW_DATA_QWORD;
924         break;
925 
926     case 0:
927     default:
928 
929         OpcSetOptimalIntegerSize (Op);
930         TrSetOpIntegerValue (PARSEOP_INTEGER, Op);
931         break;
932     }
933 
934     Op->Asl.AmlLength = 0;
935 }
936 
937 
938 /*******************************************************************************
939  *
940  * FUNCTION:    OpcAmlEvaluationWalk1
941  *
942  * PARAMETERS:  ASL_WALK_CALLBACK
943  *
944  * RETURN:      Status
945  *
946  * DESCRIPTION: Descending callback for AML execution of constant subtrees
947  *
948  ******************************************************************************/
949 
950 static ACPI_STATUS
951 OpcAmlEvaluationWalk1 (
952     ACPI_PARSE_OBJECT       *Op,
953     UINT32                  Level,
954     void                    *Context)
955 {
956     ACPI_WALK_STATE         *WalkState = Context;
957     ACPI_STATUS             Status;
958     ACPI_PARSE_OBJECT       *OutOp;
959 
960 
961     WalkState->Op = Op;
962     WalkState->Opcode = Op->Common.AmlOpcode;
963     WalkState->OpInfo = AcpiPsGetOpcodeInfo (Op->Common.AmlOpcode);
964 
965     /* Copy child pointer to Arg for compatibility with Interpreter */
966 
967     if (Op->Asl.Child)
968     {
969         Op->Common.Value.Arg = Op->Asl.Child;
970     }
971 
972     /* Call AML dispatcher */
973 
974     Status = AcpiDsExecBeginOp (WalkState, &OutOp);
975     if (ACPI_FAILURE (Status))
976     {
977         DbgPrint (ASL_PARSE_OUTPUT,
978             "%s Constant interpretation failed (1) - %s\n",
979             Op->Asl.ParseOpName, AcpiFormatException (Status));
980     }
981 
982     return (Status);
983 }
984 
985 
986 /*******************************************************************************
987  *
988  * FUNCTION:    OpcAmlEvaluationWalk2
989  *
990  * PARAMETERS:  ASL_WALK_CALLBACK
991  *
992  * RETURN:      Status
993  *
994  * DESCRIPTION: Ascending callback for AML execution of constant subtrees
995  *
996  ******************************************************************************/
997 
998 static ACPI_STATUS
999 OpcAmlEvaluationWalk2 (
1000     ACPI_PARSE_OBJECT       *Op,
1001     UINT32                  Level,
1002     void                    *Context)
1003 {
1004     ACPI_WALK_STATE         *WalkState = Context;
1005     ACPI_STATUS             Status;
1006 
1007 
1008     WalkState->Op = Op;
1009     WalkState->Opcode = Op->Common.AmlOpcode;
1010     WalkState->OpInfo = AcpiPsGetOpcodeInfo (Op->Common.AmlOpcode);
1011 
1012     /* Copy child pointer to Arg for compatibility with Interpreter */
1013 
1014     if (Op->Asl.Child)
1015     {
1016         Op->Common.Value.Arg = Op->Asl.Child;
1017     }
1018 
1019     /* Call AML dispatcher */
1020 
1021     Status = AcpiDsExecEndOp (WalkState);
1022     if (ACPI_FAILURE (Status))
1023     {
1024         DbgPrint (ASL_PARSE_OUTPUT,
1025             "%s: Constant interpretation failed (2) - %s\n",
1026             Op->Asl.ParseOpName, AcpiFormatException (Status));
1027     }
1028 
1029     return (Status);
1030 }
1031