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Silence GCC 14 warning [-Warray-bounds=] #17110

Merged
merged 3 commits into from
Oct 21, 2024
Merged

Silence GCC 14 warning [-Warray-bounds=] #17110

merged 3 commits into from
Oct 21, 2024

Commits on Oct 21, 2024

  1. Silence GCC 14 warning [-Warray-bounds=] 

    GCC reports a couple of warnings like this example:
libretro-common/cdrom/cdrom.c:395:14: warning: array subscript 6 is outside array bounds of 'unsigned char[6]' [-Warray-bounds=]
  395 |       cmd[6] = cmd[3];
      |       ~~~~~~~^~~~~~~~
libretro-common/cdrom/cdrom.c: In function 'cdrom_unlock':
libretro-common/cdrom/cdrom.c:1268:18: note: at offset 6 into object 'cdb' of size 6
 1268 |    unsigned char cdb[] = {0x1E, 0, 0, 0, 0x2, 0};

The static analysis heuristic doesn't consider the fact that the writes to cmd[6] and later only happen under the condition that `if (cmd[0] == 0xBE || cmd[0] == 0xB9)` and that in all of those cases the array passed is wide enough. So this is a false positive.

Nevertheless, there seems to be an easy way to silence the warning without disabling it: just require all arrays passed to be at least 9 bytes long and explicitly set the size of those arrays that have been shorter to 9.
    @pstef
    pstef committed Oct 21, 2024
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  2. Work around the requirement of C89 

    I used a C99 construct, but this is easy to work around
with a run-time check.
    @pstef
    pstef committed Oct 21, 2024
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  3. Restore the check for non-null cmd 

    It was obsoleted in a previous version, but is needed back now.
    @pstef
    pstef committed Oct 21, 2024
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