[Bug libsframe/29856] libsframe asan: load misaligned at sframe.c:516

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29856

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot 
gnu.org> ---
The master branch has been updated by Indu Bhagat <ibhagat@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=8c078abdc23238c2193136bf0edbf1d910615679

commit 8c078abdc23238c2193136bf0edbf1d910615679
Author: Indu Bhagat <indu.bhagat@oracle.com>
Date:   Thu Dec 15 13:12:01 2022 -0800

    libsframe asan: avoid generating misaligned loads

    There are two places where unaligned loads were seen on aarch64:
      - #1. access to the SFrame FRE stack offsets in the in-memory
        representation/abstraction provided by libsframe.
      - #2. access to the SFrame FRE start address in the on-disk
representation
        of the frame row entry.

    For #1, we can fix this by reordering the struct members of
    sframe_frame_row_entry in libsframe/sframe-api.h.

    For #2, we need to default to using memcpy instead, and copy out the bytes
    to a location for output.

    SFrame format is an unaligned on-disk format. As such, there are other
blobs
    of memory in the on-disk SFrame FRE that are on not on their natural
    boundaries.  But that does not pose further problems yet, because the users
    are provided access to the on-disk SFrame FRE data via libsframe's
    sframe_frame_row_entry, the latter has its' struct members aligned on their
    respective natural boundaries (and initialized using memcpy).

    PR 29856 libsframe asan: load misaligned at sframe.c:516

    ChangeLog:

            PR libsframe/29856
            * bfd/elf64-x86-64.c: Adjust as the struct members have been
            reordered.
            * libsframe/sframe.c (sframe_decode_fre_start_address): Use
            memcpy to perform 16-bit/32-bit reads.
            * libsframe/testsuite/libsframe.encode/encode-1.c: Adjust as the
            struct members have been reordered.

    include/ChangeLog:

            PR libsframe/29856
            * sframe-api.h: Reorder fre_offsets for natural alignment.

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