[Bug c++/29011] Python Value.dynamic_cast does not work as expected

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=29011

--- Comment #5 from Sourceware Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Hannes Domani <ssbssa@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0238b543f3c294fc8512021a40b708e8ddc72bb2

commit 0238b543f3c294fc8512021a40b708e8ddc72bb2
Author: Hannes Domani <ssbssa@yahoo.de>
Date:   Tue Mar 29 20:05:06 2022 +0200

    Fix dynamic_cast

    PR29011 notes that dynamic_cast does not work correctly if
    classes with virtual methods are involved, some of the results
    wrongly point into the vtable of the derived class:
    ```
    (gdb) p vlr
    $1 = (VirtualLeftRight *) 0x162240
    (gdb) p vl
    $2 = (VirtualLeft *) 0x162240
    (gdb) p vr
    $3 = (VirtualRight *) 0x162250
    (gdb) p dynamic_cast<VirtualLeftRight*>(vlr)
    $4 = (VirtualLeftRight *) 0x13fab89b0 <vtable for VirtualLeftRight+16>
    (gdb) p dynamic_cast<VirtualLeftRight*>(vl)
    $5 = (VirtualLeftRight *) 0x13fab89b0 <vtable for VirtualLeftRight+16>
    (gdb) p dynamic_cast<VirtualLeftRight*>(vr)
    $6 = (VirtualLeftRight *) 0x13fab89b0 <vtable for VirtualLeftRight+16>
    (gdb) p dynamic_cast<VirtualLeft*>(vlr)
    $7 = (VirtualLeft *) 0x162240
    (gdb) p dynamic_cast<VirtualLeft*>(vl)
    $8 = (VirtualLeft *) 0x13fab89b0 <vtable for VirtualLeftRight+16>
    (gdb) p dynamic_cast<VirtualLeft*>(vr)
    $9 = (VirtualLeft *) 0x162240
    (gdb) p dynamic_cast<VirtualRight*>(vlr)
    $10 = (VirtualRight *) 0x162250
    (gdb) p dynamic_cast<VirtualRight*>(vl)
    $11 = (VirtualRight *) 0x162250
    (gdb) p dynamic_cast<VirtualRight*>(vr)
    $12 = (VirtualRight *) 0x13fab89b0 <vtable for VirtualLeftRight+16>
    ```

    For the cases where the dynamic_cast type is the same as the
    original type, it used the ARG value for the result, which in
    case of pointer types was already the dereferenced value.

    And the TEM value at the value address was created with the
    pointer/reference type, not the actual class type.

    With these fixed, the dynamic_cast results make more sense:
    ```
    (gdb) p vlr
    $1 = (VirtualLeftRight *) 0x692240
    (gdb) p vl
    $2 = (VirtualLeft *) 0x692240
    (gdb) p vr
    $3 = (VirtualRight *) 0x692250
    (gdb) p dynamic_cast<VirtualLeftRight*>(vlr)
    $4 = (VirtualLeftRight *) 0x692240
    (gdb) p dynamic_cast<VirtualLeftRight*>(vl)
    $5 = (VirtualLeftRight *) 0x692240
    (gdb) p dynamic_cast<VirtualLeftRight*>(vr)
    $6 = (VirtualLeftRight *) 0x692240
    (gdb) p dynamic_cast<VirtualLeft*>(vlr)
    $7 = (VirtualLeft *) 0x692240
    (gdb) p dynamic_cast<VirtualLeft*>(vl)
    $8 = (VirtualLeft *) 0x692240
    (gdb) p dynamic_cast<VirtualLeft*>(vr)
    $9 = (VirtualLeft *) 0x692240
    (gdb) p dynamic_cast<VirtualRight*>(vlr)
    $10 = (VirtualRight *) 0x692250
    (gdb) p dynamic_cast<VirtualRight*>(vl)
    $11 = (VirtualRight *) 0x692250
    (gdb) p dynamic_cast<VirtualRight*>(vr)
    $12 = (VirtualRight *) 0x692250
    ```

    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29011
    Approved-By: Tom Tromey <tom@tromey.com>

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