[Tarantool-patches] [PATCH] build: fix linker flags for executable on MacOS

[Igor Munkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

This patch fixes inaccuracy in Tarantool build configuration introduced
by commit 07c83aab5c066ca75c149112b331b4dbb81b3f38 ('build: adjust
LuaJIT build system'). All those MacOS-related tweaks for __PAGEZERO
size and preferred load address for the bundle are necessary only for
builds with 32-bit GC area on 64-bit host. The only case fitting these
conditions is x86_64 with no LUAJIT_ENABLE_GC64. All other 64-bit builds
use 64-bit GC area unconditionally.

Part of #5983
Needed for #5629
Follows up #4862

Signed-off-by: Igor Munkin <imun@tarantool.org>
---

This patch partially fixes the build on M1. I tested it on tntmac07
alongside with the changes Nikita made for libcoro[1]. As a result
Tarantool has been successfully built, but fails to start. CI looks to
be OK[2] except the known problems with ASAN[3].

Issue: https://github.com/tarantool/tarantool/issues/5983
Branch: https://github.com/tarantool/tarantool/tree/imun/gh-5983-fix-build-on-m1

[1]: https://github.com/tarantool/tarantool/commit/309ce38
[2]: https://github.com/tarantool/tarantool/commit/5465d7b
[3]: https://github.com/tarantool/tarantool/issues/6031


 cmake/luajit.cmake | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/cmake/luajit.cmake b/cmake/luajit.cmake
index 3d37164e8..9390d0dfd 100644
--- a/cmake/luajit.cmake
+++ b/cmake/luajit.cmake
@@ -73,11 +73,21 @@ if(ENABLE_ASAN)
     add_definitions(-DLUAJIT_USE_ASAN=1)
 endif()
 
-if(TARGET_OS_DARWIN)
-    # Necessary to make LuaJIT (and Tarantool) work on Darwin, see
-    # http://luajit.org/install.html.
-    set(CMAKE_EXE_LINKER_FLAGS
-        "${CMAKE_EXE_LINKER_FLAGS} -pagezero_size 10000 -image_base 100000000")
+if(TARGET_OS_DARWIN AND NOT LUAJIT_ENABLE_GC64)
+    # XXX: This is not the best idea to build LuaJIT on MacOS
+    # with GC64 disabled. But nobody will stop you from this.
+    # You are warned. For more info see the following issue.
+    # https://github.com/tarantool/tarantool/issues/2643
+    message(WARNING "LUAJIT_ENABLE_GC64 is disabled for MacOS. "
+                    "See #2643, why this is not a good idea.")
+    # XXX: Necessary to make LuaJIT (and hence Tarantool) work on
+    # Darwin/x86_64, see the following links for more info:
+    # * http://luajit.org/install.html#embed
+    # * https://github.com/tarantool/luajit/blob/789820a/cmake/SetTargetFlags.cmake
+    if(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+        set(CMAKE_EXE_LINKER_FLAGS
+            "${CMAKE_EXE_LINKER_FLAGS} -pagezero_size 10000 -image_base 100000000")
+    endif()
 endif()
 
 # Define the locations for LuaJIT sources and artefacts.
-- 
2.25.0