[Tarantool-patches] [PATCH luajit v4 3/4] OSX: Disable unreliable assertion for external frame unwinding.

[Maksim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

From: Mike Pall <mike>

(cherry-picked from commit be251d9149b386ca0d4b51106be14366c5dbdf14)

`_Unwind_Find_FDE()` will locate the FDE if the pc is in some
function that has an associated FDE. Note, Mac OS X 10.6 and
later, introduces "compact unwind info" which the runtime uses in
preference to DWARF unwind info. This function will only work if
the target function has an FDE but no compact unwind info.
The LuaJIT VM produces compact unwind info entries, so
DWARF's FDE is not found and that assertion fails.

Maxim Kokryashkin:
* added the description for the problem

Part of tarantool/tarantool#7745
Part of tarantool/tarantool#8069
---
 src/lj_err.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/lj_err.c b/src/lj_err.c
index f6200233..975b5621 100644
--- a/src/lj_err.c
+++ b/src/lj_err.c
@@ -479,6 +479,8 @@ extern const void *_Unwind_Find_FDE(void *pc, struct dwarf_eh_bases *bases);
 /* Verify that external error handling actually has a chance to work. */
 void lj_err_verify(void)
 {
+#if !LJ_TARGET_OSX
+  /* Check disabled on MacOS due to brilliant software engineering at Apple. */
   struct dwarf_eh_bases ehb;
   /*
   ** FIXME: The following assertions were replaced with
@@ -488,6 +490,7 @@ void lj_err_verify(void)
   ** lj_assertX(_Unwind_Find_FDE((void *)_Unwind_RaiseException, &ehb), "broken build: external frame unwinding enabled, but system libraries have no unwind tables");
   */
   lua_assert(_Unwind_Find_FDE((void *)lj_err_throw, &ehb));
+#endif
   /* Check disabled, because of broken Fedora/ARM64. See #722.
   lua_assert(_Unwind_Find_FDE((void *)_Unwind_RaiseException, &ehb));
   */
-- 
2.39.2 (Apple Git-143)