Add entries for_stack_chk_guard, __ssp_canary_word, __security_cookie,
and __guard_local. As far as I can tell these are all just different
names for the same shaped functionality on different systems.
These aren't really functions, but special global variable names. They
should probably be treated the same way; all the same contexts that
need to know about emittable function names also need to know about
this. This avoids a special case check in IRSymtab.
This isn't a complete change, there's a lot more cleanup which
should be done. The stack protector configuration system is a
complete mess. There are multiple overlapping controls, used in
3 different places. Some of the target control implementations overlap
with conditions used in the emission points, and some use correlated
but not identical conditions in different contexts.
i.e. useLoadStackGuardNode, getIRStackGuard, getSSPStackGuardCheck and
insertSSPDeclarations are all used in inconsistent ways so I don't know
if I've tracked the intention of the system correctly.
The PowerPC test change is a bug fix on linux. Previously the manual
conditions were based around !isOSOpenBSD, which is not the condition
where __stack_chk_guard are used. Now getSDagStackGuard returns the
proper global reference, resulting in LOAD_STACK_GUARD getting a
MachineMemOperand which allows scheduling.
7dce16f69dc3e26cb74d5ad38b0648a6f47f9640 removed a libcall for
STACKPROTECTOR_CHECK_FAIL from OpenBSD but added no tests.
Add a basic test copied from RISCV into all the backends on
the OpenBSD page of supported architectures before I potentially
break in in RuntimeLibcalls refactoring.
