[Tarantool-patches] [PATCH luajit v2 3/6] OSX/ARM64: Disable external unwinding for now.

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

From: Mike Pall <mike>

This reduces functionality, e.g. no handling of on-trace errors.
Someone with very deep knowledge about macOS and MACH-O/DWARF stack
unwinding internals is needed to fix this. See issue #698.

(cherry picked from commit 27ee3bcd79b12a0c71f00427ee1a2e486c684486)

ARM64 interpreter doesn't have unwind info for Mach-O assembler
format, which makes unwinding impossible. Because of that
external unwinding on ARM64 MacOS is temporarily disabled.

Maxim Kokryashkin:
* added the description for the problem

Needed for tarantool/tarantool#6096
Part of tarantool/tarantool#7230
---
 cmake/SetTargetFlags.cmake | 4 +++-
 src/Makefile.original      | 5 ++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/cmake/SetTargetFlags.cmake b/cmake/SetTargetFlags.cmake
index a5a3407f..d99e1f9a 100644
--- a/cmake/SetTargetFlags.cmake
+++ b/cmake/SetTargetFlags.cmake
@@ -16,7 +16,9 @@ LuaJITTestArch(TESTARCH "${TARGET_C_FLAGS}")
 LuaJITArch(LUAJIT_ARCH "${TESTARCH}")
 
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-  AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
+  if(NOT LUAJIT_ARCH STREQUAL "arm64")
+    AppendFlags(TARGET_C_FLAGS -DLUAJIT_UNWIND_EXTERNAL)
+  endif()
 else()
   string(FIND ${TARGET_C_FLAGS} "LJ_NO_UNWIND 1" UNWIND_POS)
   if(UNWIND_POS EQUAL -1)
diff --git a/src/Makefile.original b/src/Makefile.original
index d1373b40..5826a56a 100644
--- a/src/Makefile.original
+++ b/src/Makefile.original
@@ -325,7 +325,10 @@ ifeq (Darwin,$(TARGET_SYS))
     export MACOSX_DEPLOYMENT_TARGET=10.4
   endif
   TARGET_STRIP+= -x
-  TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
+  # Ext. unwinding is broken on OSX/ARM64 until someone finds a fix. See #698.
+  ifneq (arm64,$(TARGET_LJARCH))
+    TARGET_XCFLAGS+= -DLUAJIT_UNWIND_EXTERNAL
+  endif
   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
   TARGET_DYNXLDOPTS=
   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
-- 
2.32.1 (Apple Git-133)