On 3/12/2022 12:40 PM, Roger Sayle wrote:
My recent testcase for PR c++/84964.C stress tests the middle-end by
attempting to pass a UINT_MAX sized structure on the stack. Although
my fix to PR84964 avoids the ICE after sorry() on x86_64 and similar
targets, a related issue still exists on powerpc64 (and similar
ACCUMULATE_OUTGOING_ARGS/ARGS_GROW_DOWNWARD targets) which don't
issue a "sorry, unimplemented" message, but instead ICE elsewhere.
After attempting several alternate fixes, the simplest solution is
to just defensively check in mark_stack_region_used that the upper
bound of the region lies within the allocated stack_usage_map
array, which is of size highest_outgoing_arg_in_use. When this isn't
the case, the code now follows the same path as for variable sized
regions, and uses stack_usage_watermark rather than a map.
This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check to confirm there are no surprises, and with the cc1plus
of a cross-compiler to powerpc64-linux-gnu to confirm the new test
case no longer ICEs. Ok for mainline?
2022-03-12 Roger Sayle <ro...@nextmovesoftware.com>
gcc/ChangeLog
PR middle-end/104885
* calls.cc (mark_stack_region_used): Check that the region
is within the allocated size of stack_usage_map.
OK
jeff
