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      1 /******************************************************************************
      2  *
      3  * Module Name: aslopt- Compiler optimizations
      4  *
      5  *****************************************************************************/
      6 
      7 /******************************************************************************
      8  *
      9  * 1. Copyright Notice
     10  *
     11  * Some or all of this work - Copyright (c) 1999 - 2025, 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 "aslcompiler.h"
    153 #include "aslcompiler.y.h"
    154 
    155 #include "acparser.h"
    156 #include "amlcode.h"
    157 #include "acnamesp.h"
    158 
    159 
    160 #define _COMPONENT          ACPI_COMPILER
    161         ACPI_MODULE_NAME    ("aslopt")
    162 
    163 
    164 static UINT32               OptTotal = 0;
    165 
    166 /* Local prototypes */
    167 
    168 static ACPI_STATUS
    169 OptSearchToRoot (
    170     ACPI_PARSE_OBJECT       *Op,
    171     ACPI_WALK_STATE         *WalkState,
    172     ACPI_NAMESPACE_NODE     *CurrentNode,
    173     ACPI_NAMESPACE_NODE     *TargetNode,
    174     ACPI_BUFFER             *TargetPath,
    175     char                    **NewPath);
    176 
    177 static ACPI_STATUS
    178 OptBuildShortestPath (
    179     ACPI_PARSE_OBJECT       *Op,
    180     ACPI_WALK_STATE         *WalkState,
    181     ACPI_NAMESPACE_NODE     *CurrentNode,
    182     ACPI_NAMESPACE_NODE     *TargetNode,
    183     ACPI_BUFFER             *CurrentPath,
    184     ACPI_BUFFER             *TargetPath,
    185     ACPI_SIZE               AmlNameStringLength,
    186     UINT8                   IsDeclaration,
    187     char                    **ReturnNewPath);
    188 
    189 static ACPI_STATUS
    190 OptOptimizeNameDeclaration (
    191     ACPI_PARSE_OBJECT       *Op,
    192     ACPI_WALK_STATE         *WalkState,
    193     ACPI_NAMESPACE_NODE     *CurrentNode,
    194     ACPI_NAMESPACE_NODE     *TargetNode,
    195     char                    *AmlNameString,
    196     char                    **NewPath);
    197 
    198 
    199 /*******************************************************************************
    200  *
    201  * FUNCTION:    OptSearchToRoot
    202  *
    203  * PARAMETERS:  Op                  - Current parser op
    204  *              WalkState           - Current state
    205  *              CurrentNode         - Where we are in the namespace
    206  *              TargetNode          - Node to which we are referring
    207  *              TargetPath          - External full path to the target node
    208  *              NewPath             - Where the optimized path is returned
    209  *
    210  * RETURN:      Status
    211  *
    212  * DESCRIPTION: Attempt to optimize a reference to a single 4-character ACPI
    213  *              name utilizing the search-to-root name resolution algorithm
    214  *              that is used by AML interpreters.
    215  *
    216  ******************************************************************************/
    217 
    218 static ACPI_STATUS
    219 OptSearchToRoot (
    220     ACPI_PARSE_OBJECT       *Op,
    221     ACPI_WALK_STATE         *WalkState,
    222     ACPI_NAMESPACE_NODE     *CurrentNode,
    223     ACPI_NAMESPACE_NODE     *TargetNode,
    224     ACPI_BUFFER             *TargetPath,
    225     char                    **NewPath)
    226 {
    227     ACPI_NAMESPACE_NODE     *Node;
    228     ACPI_GENERIC_STATE      ScopeInfo;
    229     ACPI_STATUS             Status;
    230     char                    *Path;
    231 
    232 
    233     ACPI_FUNCTION_NAME (OptSearchToRoot);
    234 
    235 
    236     /*
    237      * Check if search-to-root can be utilized. Use the last NameSeg of
    238      * the NamePath and 1) See if can be found and 2) If found, make
    239      * sure that it is the same node that we want. If there is another
    240      * name in the search path before the one we want, the nodes will
    241      * not match, and we cannot use this optimization.
    242      */
    243     Path = &(((char *) TargetPath->Pointer)[
    244         TargetPath->Length - ACPI_NAMESEG_SIZE]);
    245     ScopeInfo.Scope.Node = CurrentNode;
    246 
    247     /* Lookup the NameSeg using SEARCH_PARENT (search-to-root) */
    248 
    249     Status = AcpiNsLookup (&ScopeInfo, Path, ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    250         ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
    251         WalkState, &(Node));
    252     if (ACPI_FAILURE (Status))
    253     {
    254         return (Status);
    255     }
    256 
    257     /*
    258      * We found the name, but we must check to make sure that the node
    259      * matches. Otherwise, there is another identical name in the search
    260      * path that precludes the use of this optimization.
    261      */
    262     if (Node != TargetNode)
    263     {
    264         /*
    265          * This means that another object with the same name was found first,
    266          * and we cannot use this optimization.
    267          */
    268         return (AE_NOT_FOUND);
    269     }
    270 
    271     /* Found the node, we can use this optimization */
    272 
    273     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    274         "NAMESEG:   %-24s", Path));
    275 
    276     /* We must allocate a new string for the name (TargetPath gets deleted) */
    277 
    278     *NewPath = UtLocalCacheCalloc (ACPI_NAMESEG_SIZE + 1);
    279     strcpy (*NewPath, Path);
    280 
    281     if (strncmp (*NewPath, "_T_", 3))
    282     {
    283         AslError (ASL_OPTIMIZATION, ASL_MSG_SINGLE_NAME_OPTIMIZATION,
    284             Op, *NewPath);
    285     }
    286 
    287     return (AE_OK);
    288 }
    289 
    290 
    291 /*******************************************************************************
    292  *
    293  * FUNCTION:    OptBuildShortestPath
    294  *
    295  * PARAMETERS:  Op                  - Current parser op
    296  *              WalkState           - Current state
    297  *              CurrentNode         - Where we are in the namespace
    298  *              TargetNode          - Node to which we are referring
    299  *              CurrentPath         - External full path to the current node
    300  *              TargetPath          - External full path to the target node
    301  *              AmlNameStringLength - Length of the original namepath
    302  *              IsDeclaration       - TRUE for declaration, FALSE for reference
    303  *              ReturnNewPath       - Where the optimized path is returned
    304  *
    305  * RETURN:      Status
    306  *
    307  * DESCRIPTION: Build an optimal NamePath using carats
    308  *
    309  ******************************************************************************/
    310 
    311 static ACPI_STATUS
    312 OptBuildShortestPath (
    313     ACPI_PARSE_OBJECT       *Op,
    314     ACPI_WALK_STATE         *WalkState,
    315     ACPI_NAMESPACE_NODE     *CurrentNode,
    316     ACPI_NAMESPACE_NODE     *TargetNode,
    317     ACPI_BUFFER             *CurrentPath,
    318     ACPI_BUFFER             *TargetPath,
    319     ACPI_SIZE               AmlNameStringLength,
    320     UINT8                   IsDeclaration,
    321     char                    **ReturnNewPath)
    322 {
    323     UINT32                  NumCommonSegments;
    324     UINT32                  MaxCommonSegments;
    325     UINT32                  Index;
    326     UINT32                  NumCarats;
    327     UINT32                  i;
    328     char                    *NewPathInternal;
    329     char                    *NewPathExternal;
    330     ACPI_NAMESPACE_NODE     *Node;
    331     ACPI_GENERIC_STATE      ScopeInfo;
    332     ACPI_STATUS             Status;
    333     BOOLEAN                 SubPath = FALSE;
    334 
    335 
    336     ACPI_FUNCTION_NAME (OptBuildShortestPath);
    337 
    338 
    339     ScopeInfo.Scope.Node = CurrentNode;
    340 
    341     /*
    342      * Determine the maximum number of NameSegs that the Target and Current paths
    343      * can possibly have in common. (To optimize, we have to have at least 1)
    344      *
    345      * Note: The external NamePath string lengths are always a multiple of 5
    346      * (ACPI_NAMESEG_SIZE + separator)
    347      */
    348     MaxCommonSegments = TargetPath->Length / ACPI_PATH_SEGMENT_LENGTH;
    349     if (CurrentPath->Length < TargetPath->Length)
    350     {
    351         MaxCommonSegments = CurrentPath->Length / ACPI_PATH_SEGMENT_LENGTH;
    352     }
    353 
    354     /*
    355      * Determine how many NameSegs the two paths have in common.
    356      * (Starting from the root)
    357      */
    358     for (NumCommonSegments = 0;
    359          NumCommonSegments < MaxCommonSegments;
    360          NumCommonSegments++)
    361     {
    362         /* Compare two single NameSegs */
    363 
    364         Index = (NumCommonSegments * ACPI_PATH_SEGMENT_LENGTH) + 1;
    365 
    366         if (!ACPI_COMPARE_NAMESEG (
    367             &(ACPI_CAST_PTR (char, TargetPath->Pointer)) [Index],
    368             &(ACPI_CAST_PTR (char, CurrentPath->Pointer)) [Index]))
    369         {
    370             /* Mismatch */
    371 
    372             break;
    373         }
    374     }
    375 
    376     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " COMMON: %u",
    377         NumCommonSegments));
    378 
    379     /* There must be at least 1 common NameSeg in order to optimize */
    380 
    381     if (NumCommonSegments == 0)
    382     {
    383         return (AE_NOT_FOUND);
    384     }
    385 
    386     if (NumCommonSegments == MaxCommonSegments)
    387     {
    388         if (CurrentPath->Length == TargetPath->Length)
    389         {
    390             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " SAME PATH"));
    391             return (AE_NOT_FOUND);
    392         }
    393         else
    394         {
    395             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " SUBPATH"));
    396             SubPath = TRUE;
    397         }
    398     }
    399 
    400     /* Determine how many prefix Carats are required */
    401 
    402     NumCarats = (CurrentPath->Length / ACPI_PATH_SEGMENT_LENGTH) -
    403         NumCommonSegments;
    404 
    405     /*
    406      * Construct a new target string
    407      */
    408     NewPathExternal =
    409         UtLocalCacheCalloc (TargetPath->Length + NumCarats + 1);
    410 
    411     /* Insert the Carats into the Target string */
    412 
    413     for (i = 0; i < NumCarats; i++)
    414     {
    415         NewPathExternal[i] = AML_PARENT_PREFIX;
    416     }
    417 
    418     /*
    419      * Copy only the necessary (optimal) segments from the original
    420      * target string
    421      */
    422     Index = (NumCommonSegments * ACPI_PATH_SEGMENT_LENGTH) + 1;
    423 
    424     /* Special handling for exact subpath in a name declaration */
    425 
    426     if (IsDeclaration && SubPath &&
    427         (CurrentPath->Length > TargetPath->Length))
    428     {
    429         /*
    430          * The current path is longer than the target, and the target is a
    431          * subpath of the current path. We must include one more NameSeg of
    432          * the target path
    433          */
    434         Index -= ACPI_PATH_SEGMENT_LENGTH;
    435 
    436         /* Special handling for Scope() operator */
    437 
    438         if (Op->Asl.AmlOpcode == AML_SCOPE_OP)
    439         {
    440             NewPathExternal[i] = AML_PARENT_PREFIX;
    441             i++;
    442             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, "(EXTRA ^)"));
    443         }
    444     }
    445 
    446     /* Make sure we haven't gone off the end of the target path */
    447 
    448     if (Index > TargetPath->Length)
    449     {
    450         Index = TargetPath->Length;
    451     }
    452 
    453     strcpy (&NewPathExternal[i],
    454         &(ACPI_CAST_PTR (char, TargetPath->Pointer))[Index]);
    455     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " %-24s", NewPathExternal));
    456 
    457     /*
    458      * Internalize the new target string and check it against the original
    459      * string to make sure that this is in fact an optimization. If the
    460      * original string is already optimal, there is no point in continuing.
    461      */
    462     Status = AcpiNsInternalizeName (NewPathExternal, &NewPathInternal);
    463     if (ACPI_FAILURE (Status))
    464     {
    465         AslCoreSubsystemError (Op, Status, "Internalizing new NamePath",
    466             ASL_NO_ABORT);
    467         goto Cleanup;
    468     }
    469 
    470     if (strlen (NewPathInternal) >= AmlNameStringLength)
    471     {
    472         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    473             " NOT SHORTER (New %u old %u)",
    474             (UINT32) strlen (NewPathInternal),
    475             (UINT32) AmlNameStringLength));
    476 
    477         ACPI_FREE (NewPathInternal);
    478         Status = AE_NOT_FOUND;
    479         goto Cleanup;
    480     }
    481 
    482     /*
    483      * Check to make sure that the optimization finds the node we are
    484      * looking for. This is simply a sanity check on the new
    485      * path that has been created.
    486      */
    487     Status = AcpiNsLookup (&ScopeInfo, NewPathInternal,
    488         ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    489         ACPI_NS_DONT_OPEN_SCOPE, WalkState, &(Node));
    490     if (ACPI_SUCCESS (Status))
    491     {
    492         /* Found the namepath, but make sure the node is correct */
    493 
    494         if (Node == TargetNode)
    495         {
    496             /* The lookup matched the node, accept this optimization */
    497 
    498             AslError (ASL_OPTIMIZATION, ASL_MSG_NAME_OPTIMIZATION,
    499                 Op, NewPathExternal);
    500             *ReturnNewPath = NewPathInternal;
    501         }
    502         else
    503         {
    504             /* Node is not correct, do not use this optimization */
    505 
    506             Status = AE_NOT_FOUND;
    507             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " ***** WRONG NODE"));
    508             AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
    509                 "Not using optimized name - found wrong node");
    510         }
    511     }
    512     else
    513     {
    514         /* The lookup failed, we obviously cannot use this optimization */
    515 
    516         ACPI_FREE (NewPathInternal);
    517 
    518         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " ***** NOT FOUND"));
    519         AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
    520             "Not using optimized name - did not find node");
    521     }
    522 
    523 Cleanup:
    524 
    525     return (Status);
    526 }
    527 
    528 
    529 /*******************************************************************************
    530  *
    531  * FUNCTION:    OptOptimizeNameDeclaration
    532  *
    533  * PARAMETERS:  Op                  - Current parser op
    534  *              WalkState           - Current state
    535  *              CurrentNode         - Where we are in the namespace
    536  *              AmlNameString       - Unoptimized namepath
    537  *              NewPath             - Where the optimized path is returned
    538  *
    539  * RETURN:      Status. AE_OK If path is optimized
    540  *
    541  * DESCRIPTION: Perform a simple optimization of removing an extraneous
    542  *              backslash prefix if we are already at the root scope.
    543  *
    544  ******************************************************************************/
    545 
    546 static ACPI_STATUS
    547 OptOptimizeNameDeclaration (
    548     ACPI_PARSE_OBJECT       *Op,
    549     ACPI_WALK_STATE         *WalkState,
    550     ACPI_NAMESPACE_NODE     *CurrentNode,
    551     ACPI_NAMESPACE_NODE     *TargetNode,
    552     char                    *AmlNameString,
    553     char                    **NewPath)
    554 {
    555     ACPI_STATUS             Status;
    556     char                    *NewPathExternal;
    557     ACPI_NAMESPACE_NODE     *Node;
    558 
    559 
    560     ACPI_FUNCTION_TRACE (OptOptimizeNameDeclaration);
    561 
    562 
    563     if (((CurrentNode == AcpiGbl_RootNode) ||
    564         (Op->Common.Parent->Asl.ParseOpcode == PARSEOP_DEFINITION_BLOCK)) &&
    565             (ACPI_IS_ROOT_PREFIX (AmlNameString[0])))
    566     {
    567         /*
    568          * The current scope is the root, and the namepath has a root prefix
    569          * that is therefore extraneous. Remove it.
    570          */
    571         *NewPath = &AmlNameString[1];
    572 
    573         /* Debug output */
    574 
    575         Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, *NewPath,
    576             NULL, &NewPathExternal);
    577         if (ACPI_FAILURE (Status))
    578         {
    579             AslCoreSubsystemError (Op, Status, "Externalizing NamePath",
    580                 ASL_NO_ABORT);
    581             return (Status);
    582         }
    583 
    584         /*
    585          * Check to make sure that the optimization finds the node we are
    586          * looking for. This is simply a sanity check on the new
    587          * path that has been created.
    588          *
    589          * We know that we are at the root, so NULL is used for the scope.
    590          */
    591         Status = AcpiNsLookup (NULL, *NewPath,
    592             ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
    593             ACPI_NS_DONT_OPEN_SCOPE, WalkState, &(Node));
    594         if (ACPI_SUCCESS (Status))
    595         {
    596             /* Found the namepath, but make sure the node is correct */
    597 
    598             if (Node == TargetNode)
    599             {
    600                 /* The lookup matched the node, accept this optimization */
    601 
    602                 AslError (ASL_OPTIMIZATION, ASL_MSG_NAME_OPTIMIZATION,
    603                     Op, NewPathExternal);
    604 
    605                 ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    606                     "AT ROOT:   %-24s", NewPathExternal));
    607             }
    608             else
    609             {
    610                 /* Node is not correct, do not use this optimization */
    611 
    612                 Status = AE_NOT_FOUND;
    613                 ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    614                     " ***** WRONG NODE"));
    615                 AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
    616                     "Not using optimized name - found wrong node");
    617             }
    618         }
    619         else
    620         {
    621             /* The lookup failed, we obviously cannot use this optimization */
    622 
    623             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    624                 " ***** NOT FOUND"));
    625             AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
    626                 "Not using optimized name - did not find node");
    627         }
    628 
    629         ACPI_FREE (NewPathExternal);
    630         return (Status);
    631     }
    632 
    633     /* Could not optimize */
    634 
    635     return (AE_NOT_FOUND);
    636 }
    637 
    638 
    639 /*******************************************************************************
    640  *
    641  * FUNCTION:    OptOptimizeNamePath
    642  *
    643  * PARAMETERS:  Op                  - Current parser op
    644  *              Flags               - Opcode info flags
    645  *              WalkState           - Current state
    646  *              AmlNameString       - Unoptimized namepath
    647  *              TargetNode          - Node to which AmlNameString refers
    648  *
    649  * RETURN:      None. If path is optimized, the Op is updated with new path
    650  *
    651  * DESCRIPTION: Optimize a Named Declaration or Reference to the minimal length.
    652  *              Must take into account both the current location in the
    653  *              namespace and the actual reference path.
    654  *
    655  ******************************************************************************/
    656 
    657 void
    658 OptOptimizeNamePath (
    659     ACPI_PARSE_OBJECT       *Op,
    660     UINT32                  Flags,
    661     ACPI_WALK_STATE         *WalkState,
    662     char                    *AmlNameString,
    663     ACPI_NAMESPACE_NODE     *TargetNode)
    664 {
    665     ACPI_STATUS             Status;
    666     ACPI_BUFFER             TargetPath;
    667     ACPI_BUFFER             CurrentPath;
    668     ACPI_SIZE               AmlNameStringLength;
    669     ACPI_NAMESPACE_NODE     *CurrentNode;
    670     char                    *ExternalNameString;
    671     char                    *NewPath = NULL;
    672     ACPI_SIZE               HowMuchShorter;
    673     ACPI_PARSE_OBJECT       *NextOp;
    674 
    675 
    676     ACPI_FUNCTION_TRACE (OptOptimizeNamePath);
    677 
    678 
    679     /* This is an optional optimization */
    680 
    681     if (!AslGbl_ReferenceOptimizationFlag)
    682     {
    683         return_VOID;
    684     }
    685 
    686     /* Various required items */
    687 
    688     if (!TargetNode || !WalkState || !AmlNameString || !Op->Common.Parent)
    689     {
    690         return_VOID;
    691     }
    692 
    693     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    694         "PATH OPTIMIZE: Line %5d ParentOp [%12.12s] ThisOp [%12.12s] ",
    695         Op->Asl.LogicalLineNumber,
    696         AcpiPsGetOpcodeName (Op->Common.Parent->Common.AmlOpcode),
    697         AcpiPsGetOpcodeName (Op->Common.AmlOpcode)));
    698 
    699     if (!(Flags & (AML_NAMED | AML_CREATE)))
    700     {
    701         if (Op->Asl.CompileFlags & OP_IS_NAME_DECLARATION)
    702         {
    703             /* We don't want to fuss with actual name declaration nodes here */
    704 
    705             ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    706                 "******* NAME DECLARATION\n"));
    707             return_VOID;
    708         }
    709     }
    710 
    711     /*
    712      * The original path must be longer than one NameSeg (4 chars) for there
    713      * to be any possibility that it can be optimized to a shorter string
    714      */
    715     AmlNameStringLength = strlen (AmlNameString);
    716     if (AmlNameStringLength <= ACPI_NAMESEG_SIZE)
    717     {
    718         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    719             "NAMESEG %4.4s\n", AmlNameString));
    720         return_VOID;
    721     }
    722 
    723     /*
    724      * We need to obtain the node that represents the current scope -- where
    725      * we are right now in the namespace. We will compare this path
    726      * against the Namepath, looking for commonality.
    727      */
    728     CurrentNode = AcpiGbl_RootNode;
    729     if (WalkState->ScopeInfo)
    730     {
    731         CurrentNode = WalkState->ScopeInfo->Scope.Node;
    732     }
    733 
    734     if (Flags & (AML_NAMED | AML_CREATE))
    735     {
    736         /* This is the declaration of a new name */
    737 
    738         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, "NAME\n"));
    739 
    740         /*
    741          * The node of interest is the parent of this node (the containing
    742          * scope). The actual namespace node may be up more than one level
    743          * of parse op or it may not exist at all (if we traverse back
    744          * up to the root.)
    745          */
    746         NextOp = Op->Asl.Parent;
    747         while (NextOp && (!NextOp->Asl.Node))
    748         {
    749             NextOp = NextOp->Asl.Parent;
    750         }
    751 
    752         if (NextOp && NextOp->Asl.Node)
    753         {
    754             CurrentNode = NextOp->Asl.Node;
    755         }
    756         else
    757         {
    758             CurrentNode = AcpiGbl_RootNode;
    759         }
    760     }
    761     else
    762     {
    763         /* This is a reference to an existing named object */
    764 
    765         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, "REFERENCE\n"));
    766     }
    767 
    768     /*
    769      * Obtain the full paths to the two nodes that we are interested in
    770      * (Target and current namespace location) in external
    771      * format -- something we can easily manipulate
    772      */
    773     TargetPath.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
    774     Status = AcpiNsHandleToPathname (TargetNode, &TargetPath, FALSE);
    775     if (ACPI_FAILURE (Status))
    776     {
    777         AslCoreSubsystemError (Op, Status, "Getting Target NamePath",
    778             ASL_NO_ABORT);
    779         return_VOID;
    780     }
    781 
    782     TargetPath.Length--;    /* Subtract one for null terminator */
    783 
    784     /* CurrentPath is the path to this scope (where we are in the namespace) */
    785 
    786     CurrentPath.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
    787     Status = AcpiNsHandleToPathname (CurrentNode, &CurrentPath, FALSE);
    788     if (ACPI_FAILURE (Status))
    789     {
    790         AslCoreSubsystemError (Op, Status, "Getting Current NamePath",
    791             ASL_NO_ABORT);
    792         return_VOID;
    793     }
    794 
    795     CurrentPath.Length--;   /* Subtract one for null terminator */
    796 
    797     /* Debug output only */
    798 
    799     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, AmlNameString,
    800         NULL, &ExternalNameString);
    801     if (ACPI_FAILURE (Status))
    802     {
    803         AslCoreSubsystemError (Op, Status, "Externalizing NamePath",
    804             ASL_NO_ABORT);
    805         return_VOID;
    806     }
    807 
    808     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    809         "CURRENT SCOPE: (%2u) %-37s FULL PATH TO NAME: (%2u) %-32s ACTUAL AML:%-32s\n",
    810         (UINT32) CurrentPath.Length, (char *) CurrentPath.Pointer,
    811         (UINT32) TargetPath.Length, (char *) TargetPath.Pointer,
    812         ExternalNameString));
    813 
    814     ACPI_FREE (ExternalNameString);
    815 
    816     /*
    817      * Attempt an optimization depending on the type of namepath
    818      */
    819     if (Flags & (AML_NAMED | AML_CREATE))
    820     {
    821         /*
    822          * This is a named opcode and the namepath is a name declaration, not
    823          * a reference.
    824          */
    825         Status = OptOptimizeNameDeclaration (Op, WalkState, CurrentNode,
    826             TargetNode, AmlNameString, &NewPath);
    827         if (ACPI_FAILURE (Status))
    828         {
    829             /*
    830              * 2) now attempt to
    831              *    optimize the namestring with carats (up-arrow)
    832              */
    833             Status = OptBuildShortestPath (Op, WalkState, CurrentNode,
    834                 TargetNode, &CurrentPath, &TargetPath,
    835                 AmlNameStringLength, 1, &NewPath);
    836         }
    837     }
    838     else
    839     {
    840         /*
    841          * This is a reference to an existing named object
    842          *
    843          * 1) Check if search-to-root can be utilized using the last
    844          *    NameSeg of the NamePath
    845          */
    846         Status = OptSearchToRoot (Op, WalkState, CurrentNode,
    847             TargetNode, &TargetPath, &NewPath);
    848         if (ACPI_FAILURE (Status))
    849         {
    850             /*
    851              * 2) Search-to-root could not be used, now attempt to
    852              *    optimize the namestring with carats (up-arrow)
    853              */
    854             Status = OptBuildShortestPath (Op, WalkState, CurrentNode,
    855                 TargetNode, &CurrentPath, &TargetPath,
    856                 AmlNameStringLength, 0, &NewPath);
    857         }
    858     }
    859 
    860     /*
    861      * Success from above indicates that the NamePath was successfully
    862      * optimized. We need to update the parse op with the new name
    863      */
    864     if (ACPI_SUCCESS (Status))
    865     {
    866         HowMuchShorter = (AmlNameStringLength - strlen (NewPath));
    867         OptTotal += HowMuchShorter;
    868 
    869         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
    870             " REDUCED BY %2u (TOTAL SAVED %2u)",
    871             (UINT32) HowMuchShorter, OptTotal));
    872 
    873         if (Flags & AML_NAMED)
    874         {
    875             if (Op->Asl.AmlOpcode == AML_ALIAS_OP)
    876             {
    877                 /*
    878                  * ALIAS is the only oddball opcode, the name declaration
    879                  * (alias name) is the second operand
    880                  */
    881                 Op->Asl.Child->Asl.Next->Asl.Value.String = NewPath;
    882                 Op->Asl.Child->Asl.Next->Asl.AmlLength = strlen (NewPath);
    883             }
    884             else
    885             {
    886                 Op->Asl.Child->Asl.Value.String = NewPath;
    887                 Op->Asl.Child->Asl.AmlLength = strlen (NewPath);
    888             }
    889         }
    890         else if (Flags & AML_CREATE)
    891         {
    892             /* Name must appear as the last parameter */
    893 
    894             NextOp = Op->Asl.Child;
    895             while (!(NextOp->Asl.CompileFlags & OP_IS_NAME_DECLARATION))
    896             {
    897                 NextOp = NextOp->Asl.Next;
    898             }
    899             /* Update the parse node with the new NamePath */
    900 
    901             NextOp->Asl.Value.String = NewPath;
    902             NextOp->Asl.AmlLength = strlen (NewPath);
    903         }
    904         else
    905         {
    906             /* Update the parse node with the new NamePath */
    907 
    908             Op->Asl.Value.String = NewPath;
    909             Op->Asl.AmlLength = strlen (NewPath);
    910         }
    911     }
    912     else
    913     {
    914         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, " ALREADY OPTIMAL"));
    915     }
    916 
    917     /* Cleanup path buffers */
    918 
    919     ACPI_FREE (TargetPath.Pointer);
    920     ACPI_FREE (CurrentPath.Pointer);
    921 
    922     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS, "\n"));
    923     return_VOID;
    924 }
    925