From: Sebastian Reitenbach <sebastia@l00-bugdead-prods.de>
Subject: Re: x11/gnustep/libobjc2: enable cache on powerpc
To: George Koehler <kernigh@gmail.com>
Cc: ports@openbsd.org
Date: Wed, 10 Sep 2025 08:23:39 +0200

On Wed, Sep 10, 2025 at 5:11 AM George Koehler <kernigh@gmail.com> wrote:

> x11/gnustep/libobjc2 is disabling its objc_method_cache_version only
> on powerpc.  This broke x11/gnustep/base, which assumes that
> objc_method_cache_version exists.  With this patch, it exists and my
> powerpc can build base and run x11/gnustep/terminal.
>
> objc_method_cache_version is a 64-bit atomic variable.  Most archs
> have 64-bit atomic ops in hardware, but powerpc needs software
> functions like __atomic_fetch_add_8.  Enabling it might cause trouble
> with gcc (missing -latomic), but works on OpenBSD with clang and
> libcompiler_rt.
>



IIRC, libobjc2 isn't really meant to be built with gcc anyways.

I don't have such platform around to test, but if it works for you,

OK sebastia@



>
> ok?
> --gkoehler
>
> Index: Makefile
> ===================================================================
> RCS file: /cvs/ports/x11/gnustep/libobjc2/Makefile,v
> diff -u -p -r1.39 Makefile
> --- Makefile    22 Apr 2024 06:47:57 -0000      1.39
> +++ Makefile    10 Sep 2025 01:49:50 -0000
> @@ -9,6 +9,7 @@ GH_PROJECT =    libobjc2
>  GH_TAGNAME =   v${VERSION}
>  DISTNAME =     libobjc2-${VERSION:S/_//}
>  PKGNAME =      gnustep-${DISTNAME}
> +REVISION =     0
>
>  SHARED_LIBS += objc2   3.0
>  SHARED_LIBS +=  objcxx 2.0
> Index: patches/patch-CMakeLists_txt
> ===================================================================
> RCS file: patches/patch-CMakeLists_txt
> diff -N patches/patch-CMakeLists_txt
> --- /dev/null   1 Jan 1970 00:00:00 -0000
> +++ patches/patch-CMakeLists_txt        10 Sep 2025 01:49:50 -0000
> @@ -0,0 +1,14 @@
> +Enable objc_method_cache_version on powerpc.
> +
> +Index: CMakeLists.txt
> +--- CMakeLists.txt.orig
> ++++ CMakeLists.txt
> +@@ -188,7 +188,7 @@ add_compile_options($<$<STREQUAL:${CMAKE_SYSTEM_PROCES
> + # which is used in safe caching.
> + # You must also update the guard in objc/runtime.h, when updating
> + # this macro.
> +-if (ARCHITECTURE STREQUAL "powerpc")
> ++if (OFF AND ARCHITECTURE STREQUAL "powerpc")
> +       add_definitions(-DNO_SAFE_CACHING)
> + endif()
> +
> Index: patches/patch-objc_slot_h
> ===================================================================
> RCS file: patches/patch-objc_slot_h
> diff -N patches/patch-objc_slot_h
> --- /dev/null   1 Jan 1970 00:00:00 -0000
> +++ patches/patch-objc_slot_h   10 Sep 2025 01:49:50 -0000
> @@ -0,0 +1,14 @@
> +Enable objc_method_cache_version on powerpc.
> +
> +Index: objc/slot.h
> +--- objc/slot.h.orig
> ++++ objc/slot.h
> +@@ -31,7 +31,7 @@ struct objc_slot2
> +  * Caching is disabled on targets without native 64-bit atomics support
> such
> +  * as PowerPC 32-bit.
> +  */
> +-#if defined(__powerpc__) && !defined(__powerpc64__)
> ++#if 0 && defined(__powerpc__) && !defined(__powerpc64__)
> + #else
> + OBJC_PUBLIC extern _Atomic(uint64_t) objc_method_cache_version;
> + #endif
>