This test was problematic, and also unnecessary. It's not really a test of the libc functionality or ABI. That's already covered by the LlvmLibcStackChkFail.Death test. The Smash test was in fact just testing that the compiler produces the call in the expected situation. That's a compiler test, not a libc test. It's not really feasible to make a test like this both reliable and safe. Since it's not something libc needs to test, it's not worth trying.
Reverts llvm/llvm-project#125763 This causes failures in asan. More thought is needed.
Previously this test was entirely disabled under asan, but not hwasan. Instead of disabling the test, make the test compatible with both asan and hwasan by disabling sanitizers only on the subroutine that does the stack-smashing.
Currently the nan* functions use nullptr dereferencing to crash with SIGSEGV if the input is nullptr. Both `nan(nullptr)` and `nullptr` dereferencing are undefined behaviors according to the C standard. Employing `nullptr` dereference in the `nan` function implementation is ok if users only linked against the pre-built library, but it might be completely removed by the compilers' optimizations if it is built from source together with the users' code. See for instance: https://godbolt.org/z/fd8KcM9bx This PR uses volatile load to prevent the undefined behavior if libc is built without sanitizers, and leave the current undefined behavior if libc is built with sanitizers, so that the undefined behavior can be caught for users' codes.
With some header fix forward for GPU builds.
Build bots are failing in post submit. Unclear why but can't reproduce locally. Disable this test for asan for now.
Looks like adding attributes to lambdas wasn't added to ISO C++ until C++23. Forget lambdas and just use a static function.
Otherwise for ASAN configured runs of the test, the test will fail due to the sanitizer rather than via SIGABRT.
Use a size smaller than the smallest supported page size so that we don't clobber over any guard pages, which may result in a segfault before __stack_chk_fail can be called. Also, move __stack_chk_fail outside of our namespace.
__stack_chk_fail should be provided by libc.a, not startup files. Add __stack_chk_fail to existing linux and arm entrypoints. On Windows (when not targeting MinGW), it seems that the corresponding function identifier is __security_check_cookie, so no entrypoint is added for Windows. Baremetal targets also ought to be compileable with `-fstack-protector*` There is no common header for this prototype, since calls to __stack_chk_fail are meant to be inserted by the compiler upon function return when compiled `-fstack-protector*`.