Workaround for ASAN failure in _ws_mempbrk_sse42

When ASAN is enabled, a false buffer overflow warning is raised. It is
a false positive since everything starting at '\0' will get ignored by
the PCMPISTRI instruction (see Intel(r) SSE4 Programming Reference,
5.3.1.5 "Valid/Invalid Override of Comparisons", and 5.3.1.2
"Aggregrate Operation", case "Equal any").

Concerns about reading past the end of the page turns out to be false,
there always seem to be a valid page after the current one (for static
and heap memory at least). It is an non-issue since strlen also does
not have issues with this.

Rather than fully disabling SSE 4.2 and using the fallback
implementation for ASAN-enabled builds, read the set of characters from
'a' into the mask without a 128-bit read and then still use SSE 4.2
for the actual query.

Bug: 10214
Change-Id: Ie4a526e60b43bfc08dd1d821556766f14a49be4d
Reviewed-on: https://code.wireshark.org/review/2618
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Evan Huus <eapache@gmail.com>

0 files changed, 0 insertions, 0 deletions