This patch adds a configuration of the libc++ test suite that enables
optimizations when building the tests. It also adds a new CI
configuration to exercise this on a regular basis. This is added in the
context of [1], which requires building with optimizations in order to
hit the bug.
[1]: https://github.com/llvm/llvm-project/issues/68552
`unw_getcontext` saves the caller's registers in the context. However,
if the caller of `unw_getcontext` is in a different module, the glue
code of `unw_getcontext` sets the TOC register (r2) with the new TOC
base and saves the original TOC register value in the stack frame. This
causes the incorrect TOC value is used when the caller steps up frames,
which fails libunwind LIT test case `unw_resume.pass.cpp`. This PR fixes
the problem by using the original TOC register value saved in the stack
if the caller is in a different module and enables `unw_resume.pass.cpp`
on AIX.
$ra should be restored before $a0, otherwise the baseaddress ($a0) would
be destroyed. See file `UnwindRegistersSave.S` for reference.
This also makes libcxx and libcxxabi regtest pass for the `-DLIBCXXABI_USE_LLVM_UNWINDER=ON` build.
Reviewed By: MaskRay, xen0n, #libunwind
Differential Revision: https://reviews.llvm.org/D147372
This is here for local unwinding, which unw_resume() restores
the machine state and then directly resumes execution in the
target stack frame.
Reviewed By: wangleiat
Differential Revision: https://reviews.llvm.org/D147371
