tree 26dabd25a32d481a14159eb6bc8311b911896651
parent 96e8eeb75f178f4cf7a315d4ed50ed8466edd28b
author Xing Xue <xingxue@outlook.com> 1654003294 -0400
committer Copybara-Service <copybara-worker@google.com> 1654003557 -0700

[libc++abi][AIX] add personality and helper functions for the state table EH

Summary:
This patch adds the personality and helper functions for the state table based EH used by IBM legacy compilers xlC and xlclang++ on AIX.

 * A high level description of the state table based EH is provided in the code comments.

 * Function scan_state_tab() is added to scan the state table. It is invoked by the state table personality routine __xlcxx_personality_v0() and returns scan_results like scan_eh_tab() does.

 * A couple of EH helper functions used by xlC and xlclang++ generated code are also added, e.g., __xlc_catch_matchv2() which checks whether the thrown object matches the catch handler's exception type.

 * Debugging macros _LIBCXXABI_TRACE_STATETAB, _LIBCXXABI_TRACE_STATETAB0, and _LIBCXXABI_TRACING_STATETAB are added to dump state table scanning traces if environment variable LIBCXXABI_PRINT_STATTAB is set.

 * The state variable and state table data is the LSDA found from the traceback table of the function during unwinding.

Reviewed by: MaskRay, cebowleratibm, libc++abi

Differential Revision: https://reviews.llvm.org/D100504

GitOrigin-RevId: b8f5732634feaf7a9ce37d33f97f1fb490efeddd