eb42305f (jit: avoid integer wraparound in stack size definition (#42),
2021-11-19) introduces a check to avoid an integer overflow when
allocating stack size for JIT.
Unfortunately the maximum value was using PCRE2_SIZE_MAX, eventhough
the variable is of type size_t, so correct it.
Practically; the issue shouldn't affect the most common configurations
where both values are the same, and it will be unlikely that there would
be a configuration where PCRE2_SIZE_MAX > SIZE_MAX, hence the mistake
is unlikely to have reintroduced the original bug and this change should
be therefore mostly equivalent.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
On CHERI, and thus Arm's Morello prototype, pointers are represented as
hardware capabilities, which consist of both an integer address and
additional metadata, meaning they are twice the size of the platform's
size_t type, i.e. 16 bytes on a 64-bit system. The ovector member of
heapframe happens to only be 8 byte aligned, and so computing frame_size
ends up with a multiple of 8 but not 16. Whilst the first frame is
always suitably aligned, this then misaligns the frame that follows it,
resulting in an alignment fault when storing a pointer to Fecode at the
start of match.
Thus, round up frame_size to a multiple of heapframe's alignment to
ensure alignment is preserved. This can be completely optimised away on
traditional architectures and, since CHERI's capabilities are in fact
2 * sizeof(PCRE2_SIZE) bytes in size, the variable part of the
expression is also proven to be a multiple of the alignment and so the
aligning gets folded into the offsetof part by adding an additional 8,
so no dynamic alignment code is needed even on CHERI architectures.
Notably, running the script directly from a build subdirectory will
infer srcdir as .. if not otherwise set, but doesn't work for these.
With this commit sh pcre2_grep_test.sh works as expected.
Adam
Philip Hazel
Zoltan Herczeg
Carlo Marcelo Arenas Belón
Jessica Clarke
Michael Kaufmann
Zoltan Herczeg