Recent GCC 10 trunk in C++20 mode reports issues like
> include/opencl/OpenCLZone.hxx:27:9: error: ‘++’ expression of ‘volatile’-qualified type is deprecated [-Werror=volatile]
> 27 | gnEnterCount++;
> | ^~~~~~~~~~~~
But unlike in the case of ec17c8ec52
"-Werror=volatile in OpenGLZone",
* it looks like there are no multi-threading issues here, and the counters are
just accessed (via OpenCLZone::isInZone) from the VCLExceptionSignal_impl
signal handler in addition to being modified (via OpenCLZone RAII objects)
from mainline code; and
* from the usage pattern of gnEnterCount and gnLeaveCount it appears that they
can be combined into a single counter.
(f41eb66302 "opencl: OpenCLZone, detect CL
device change and disable CL on crash" presumably modelled OpenCLZone naively
after OpenGLZone, without simplifying it where possible.) One minor advantage
of having two monotonically increasing counters is that when they overflow,
the implementation of isInZone (comparing them for equality) still gives
~useful results (assuming that a false "match" of non-overflown gnEnterCount
against overflown gnLeaveCount is highly unlikely). But instances of
OpenCLZone RAII objects are presumably never nested very deeply (if at all),
so that the newly added "TODO: overflow" comment (which would even cause UB if
std::sig_atomic_t is signed) is probably of no practical concern.
Change-Id: I92e1f2c46ca996a0a86bacabcda2accba5eb6298
Reviewed-on: https://gerrit.libreoffice.org/79106
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
33d922ea07