dist/compiler/asllookup.c

/******************************************************************************
 *
 * Module Name: asllookup- Namespace lookup functions
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
 * All rights reserved.
 *
 * 2. License
 *
 * 2.1. This is your license from Intel Corp. under its intellectual property
 * rights. You may have additional license terms from the party that provided
 * you this software, covering your right to use that party's intellectual
 * property rights.
 *
 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
 * copy of the source code appearing in this file ("Covered Code") an
 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
 * base code distributed originally by Intel ("Original Intel Code") to copy,
 * make derivatives, distribute, use and display any portion of the Covered
 * Code in any form, with the right to sublicense such rights; and
 *
 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
 * license (with the right to sublicense), under only those claims of Intel
 * patents that are infringed by the Original Intel Code, to make, use, sell,
 * offer to sell, and import the Covered Code and derivative works thereof
 * solely to the minimum extent necessary to exercise the above copyright
 * license, and in no event shall the patent license extend to any additions
 * to or modifications of the Original Intel Code. No other license or right
 * is granted directly or by implication, estoppel or otherwise;
 *
 * The above copyright and patent license is granted only if the following
 * conditions are met:
 *
 * 3. Conditions
 *
 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification with rights to further distribute source must include
 * the above Copyright Notice, the above License, this list of Conditions,
 * and the following Disclaimer and Export Compliance provision. In addition,
 * Licensee must cause all Covered Code to which Licensee contributes to
 * contain a file documenting the changes Licensee made to create that Covered
 * Code and the date of any change. Licensee must include in that file the
 * documentation of any changes made by any predecessor Licensee. Licensee
 * must include a prominent statement that the modification is derived,
 * directly or indirectly, from Original Intel Code.
 *
 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification without rights to further distribute source must
 * include the following Disclaimer and Export Compliance provision in the
 * documentation and/or other materials provided with distribution. In
 * addition, Licensee may not authorize further sublicense of source of any
 * portion of the Covered Code, and must include terms to the effect that the
 * license from Licensee to its licensee is limited to the intellectual
 * property embodied in the software Licensee provides to its licensee, and
 * not to intellectual property embodied in modifications its licensee may
 * make.
 *
 * 3.3. Redistribution of Executable. Redistribution in executable form of any
 * substantial portion of the Covered Code or modification must reproduce the
 * above Copyright Notice, and the following Disclaimer and Export Compliance
 * provision in the documentation and/or other materials provided with the
 * distribution.
 *
 * 3.4. Intel retains all right, title, and interest in and to the Original
 * Intel Code.
 *
 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
 * Intel shall be used in advertising or otherwise to promote the sale, use or
 * other dealings in products derived from or relating to the Covered Code
 * without prior written authorization from Intel.
 *
 * 4. Disclaimer and Export Compliance
 *
 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
 * PARTICULAR PURPOSE.
 *
 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
 * LIMITED REMEDY.
 *
 * 4.3. Licensee shall not export, either directly or indirectly, any of this
 * software or system incorporating such software without first obtaining any
 * required license or other approval from the U. S. Department of Commerce or
 * any other agency or department of the United States Government. In the
 * event Licensee exports any such software from the United States or
 * re-exports any such software from a foreign destination, Licensee shall
 * ensure that the distribution and export/re-export of the software is in
 * compliance with all laws, regulations, orders, or other restrictions of the
 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 * any of its subsidiaries will export/re-export any technical data, process,
 * software, or service, directly or indirectly, to any country for which the
 * United States government or any agency thereof requires an export license,
 * other governmental approval, or letter of assurance, without first obtaining
 * such license, approval or letter.
 *
 *****************************************************************************
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * following license:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 *****************************************************************************/

#include "aslcompiler.h"
#include "aslcompiler.y.h"
#include "acparser.h"
#include "amlcode.h"
#include "acnamesp.h"
#include "acdispat.h"


#define _COMPONENT          ACPI_COMPILER
        ACPI_MODULE_NAME    ("asllookup")

/* Local prototypes */

static ACPI_STATUS
LkIsObjectUsed (
    ACPI_HANDLE             ObjHandle,
    UINT32                  Level,
    void                    *Context,
    void                    **ReturnValue);

static ACPI_PARSE_OBJECT *
LkGetNameOp (
    ACPI_PARSE_OBJECT       *Op);


/*******************************************************************************
 *
 * FUNCTION:    LkFindUnreferencedObjects
 *
 * PARAMETERS:  None
 *
 * RETURN:      None
 *
 * DESCRIPTION: Namespace walk to find objects that are not referenced in any
 *              way. Must be called after the namespace has been cross
 *              referenced.
 *
 ******************************************************************************/

void
LkFindUnreferencedObjects (
    void)
{

    /* Walk entire namespace from the supplied root */

    (void) AcpiNsWalkNamespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
                ACPI_UINT32_MAX, FALSE, LkIsObjectUsed, NULL,
                NULL, NULL);
}


/*******************************************************************************
 *
 * FUNCTION:    LkIsObjectUsed
 *
 * PARAMETERS:  ACPI_WALK_CALLBACK
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Check for an unreferenced namespace object and emit a warning.
 *              We have to be careful, because some types and names are
 *              typically or always unreferenced, we don't want to issue
 *              excessive warnings. Note: Names that are declared within a
 *              control method are temporary, so we always issue a remark
 *              if they are not referenced.
 *
 ******************************************************************************/

static ACPI_STATUS
LkIsObjectUsed (
    ACPI_HANDLE             ObjHandle,
    UINT32                  Level,
    void                    *Context,
    void                    **ReturnValue)
{
    ACPI_NAMESPACE_NODE     *Node = ACPI_CAST_PTR (ACPI_NAMESPACE_NODE, ObjHandle);
    ACPI_NAMESPACE_NODE     *Next;
    ASL_METHOD_LOCAL        *MethodLocals;
    ASL_METHOD_LOCAL        *MethodArgs;
    UINT32                  i;


    if (Node->Type == ACPI_TYPE_METHOD)
    {
        if (!Node->Op || !Node->MethodLocals)
        {
            return (AE_OK);
        }

        MethodLocals = (ASL_METHOD_LOCAL *) Node->MethodLocals;
        MethodArgs = (ASL_METHOD_LOCAL *) Node->MethodArgs;

        /*
         * Analysis of LocalX variables
         */
        for (i = 0; i < ACPI_METHOD_NUM_LOCALS; i++)
        {
            /* Warn for Locals that are set but never referenced */

            if ((MethodLocals[i].Flags & ASL_LOCAL_INITIALIZED) &&
                (!(MethodLocals[i].Flags & ASL_LOCAL_REFERENCED)))
            {
                sprintf (AslGbl_MsgBuffer, "Local%u", i);
                AslError (ASL_WARNING, ASL_MSG_LOCAL_NOT_USED,
                    MethodLocals[i].Op, AslGbl_MsgBuffer);
            }
        }

        /*
         * Analysis of ArgX variables (standard method arguments,
         * and remaining unused ArgX can also be used as locals)
         */
        for (i = 0; i < ACPI_METHOD_NUM_ARGS; i++)
        {
            if (MethodArgs[i].Flags & ASL_ARG_IS_LOCAL)
            {
                /* Warn if ArgX is being used as a local, but not referenced */

                if ((MethodArgs[i].Flags & ASL_ARG_INITIALIZED) &&
                    (!(MethodArgs[i].Flags & ASL_ARG_REFERENCED)))
                {
                    sprintf (AslGbl_MsgBuffer, "Arg%u", i);
                    AslError (ASL_WARNING, ASL_MSG_ARG_AS_LOCAL_NOT_USED,
                        MethodArgs[i].Op, AslGbl_MsgBuffer);
                }
            }
            else
            {
                /*
                 * Remark if a normal method ArgX is not referenced.
                 * We ignore the predefined methods since often, not
                 * all arguments are needed or used.
                 */
                if ((Node->Name.Ascii[0] != '_') &&
                    (!(MethodArgs[i].Flags & ASL_ARG_REFERENCED)))
                {
                    sprintf (AslGbl_MsgBuffer, "Arg%u", i);
                    AslError (ASL_REMARK, ASL_MSG_ARG_NOT_USED,
                        MethodArgs[i].Op, AslGbl_MsgBuffer);
                }
            }
        }
    }

    /* Referenced flag is set during the namespace xref */

    if (Node->Flags & ANOBJ_IS_REFERENCED)
    {
        return (AE_OK);
    }

    if (!Node->Op)
    {
        return (AE_OK);
    }

    /* These types are typically never directly referenced, ignore them */

    switch (Node->Type)
    {
    case ACPI_TYPE_DEVICE:
    case ACPI_TYPE_PROCESSOR:
    case ACPI_TYPE_POWER:
    case ACPI_TYPE_THERMAL:
    case ACPI_TYPE_LOCAL_RESOURCE:
    case ACPI_TYPE_LOCAL_RESOURCE_FIELD: /* Names assigned to descriptor elements */

        return (AE_OK);

    default:

        break;
    }

    /* Determine if the name is within a control method */

    Next = Node->Parent;
    while (Next)
    {
        if (Next->Type == ACPI_TYPE_METHOD)
        {
            /*
             * Name is within a method, therefore it is temporary.
             * Issue a remark even if it is a reserved name (starts
             * with an underscore).
             */
            snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Name [%4.4s] is within a method [%4.4s]",
                Node->Name.Ascii, Next->Name.Ascii);
            AslError (ASL_REMARK, ASL_MSG_NOT_REFERENCED,
                LkGetNameOp (Node->Op), AslGbl_MsgBuffer);
            return (AE_OK);
        }

        Next = Next->Parent;
    }

    /* The name is not within a control method */

    /*
     * Ignore names that start with an underscore. These are the reserved
     * ACPI names and are typically not referenced since they are meant
     * to be called by the host OS.
     */
    if (Node->Name.Ascii[0] == '_')
    {
        return (AE_OK);
    }

    /*
     * What remains is an unresolved user name that is not within a method.
     * However, the object could be referenced via another table, so issue
     * the warning at level 2.
     */
    AslError (ASL_WARNING2, ASL_MSG_NOT_REFERENCED,
        LkGetNameOp (Node->Op), NULL);
    return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    LkGetNameOp
 *
 * PARAMETERS:  Op              - Current Op
 *
 * RETURN:      NameOp associated with the input op
 *
 * DESCRIPTION: Find the name declaration op associated with the operator
 *
 ******************************************************************************/

static ACPI_PARSE_OBJECT *
LkGetNameOp (
    ACPI_PARSE_OBJECT       *Op)
{
    const ACPI_OPCODE_INFO  *OpInfo;
    ACPI_PARSE_OBJECT       *NameOp = Op;


    OpInfo = AcpiPsGetOpcodeInfo (Op->Asl.AmlOpcode);


    /* Get the NamePath from the appropriate place */

    if (OpInfo->Flags & AML_NAMED)
    {
        /* For nearly all NAMED operators, the name reference is the first child */

        NameOp = Op->Asl.Child;
        if (Op->Asl.AmlOpcode == AML_ALIAS_OP)
        {
            /*
             * ALIAS is the only oddball opcode, the name declaration
             * (alias name) is the second operand
             */
            NameOp = Op->Asl.Child->Asl.Next;
        }
    }
    else if (OpInfo->Flags & AML_CREATE)
    {
        /* Name must appear as the last parameter */

        NameOp = Op->Asl.Child;
        while (!(NameOp->Asl.CompileFlags & OP_IS_NAME_DECLARATION))
        {
            NameOp = NameOp->Asl.Next;
        }
    }

    return (NameOp);
}