Re: arch-defines: also set LLD_EMUL if USE_LLD is set

On 2019/12/04 12:17, Marc Espie wrote:
> On Wed, Dec 04, 2019 at 10:48:06AM +0000, Stuart Henderson wrote:
> > Currently LLD_EMUL is only set for LLD_ARCHS (aarch64 amd64 arm i386).
> > A diff to unbreak mupdf build on mips64 requires linking with lld and this
> > variable is required. Rather than adding a custom LLD_EMUL definition in
> > mupdf let's just make the arch-defines.mk one reachable.
> >
> > OK?
> >
> > Index: arch-defines.mk
> > ===================================================================
> > RCS file: /cvs/ports/infrastructure/mk/arch-defines.mk,v
> > retrieving revision 1.69
> > diff -u -p -1 -1 -r1.69 arch-defines.mk
> > --- arch-defines.mk 9 Nov 2019 15:08:09 -0000 1.69
> > +++ arch-defines.mk 4 Dec 2019 10:45:44 -0000
> > @@ -57,23 +57,23 @@ DEBUG_PACKAGES =
> > DEBUG_FILES =
> > .endif
> >
> > .if ${PROPERTIES:Mclang}
> > LIBCXX = c++ c++abi pthread
> > LIBECXX = c++ c++abi pthread
> > .else
> > LIBCXX = stdc++ pthread
> > LIBECXX = estdc++>=17 pthread
> > .endif
> >
> > -.if ${PROPERTIES:Mlld}
> > +.if ${PROPERTIES:Mlld} || defined(USE_LLD) && ${USE_LLD:L} == yes
> > # see llvm/tools/lld/ELF/Driver.cpp
> > . for A in aarch64.aarch64elf amd64.elf_amd64 arm.armelf i386.elf_i386 \
> > mips64.elf64btsmip mips64el.elf64ltsmip powerpc.elf32ppc \
> > sparc64.elf64_sparc
> > . if ${MACHINE_ARCH} == ${A:R}
> > LLD_EMUL = -m${A:E}
> > . endif
> > . endfor
> > .else
> > LLD_EMUL =
> > .endif
> >
> Would there be a downside to just always set LLD_EMUL ?

It needs to use different strings depending on the linker used:

arch ld.bfd ld.lld
i386 elf_i386_obsd elf_i386
amd64 elf_x86_64_obsd elf_amd64
aarch64 n/a aarch64elf
arm armelf_obsd armelf
mips64 elf64btsmip_obsd elf64btsmip
mips64el elf64ltsmip_obsd elf64ltsmip
powerpc elf32ppc_obsd elf32ppc
sparc64 elf64_sparc_obsd elf64_sparc64

Since ld.bfd has a default anyway, it seems easier to leave it unset
rather than carry a second table plus risk breakage (not that this is
really widely used; only mupdf, net/utox, www/mozplugger).

> By the way, I would probably code it differently to avoid the loop and
> expensive computations:
> _LLD_EMUL_aarch64 = aarch64elf
> ...
> .if defined(_LLD_EMUL_${MACHINE_ARCH})
> LLD_EMUL = -m${_LLD_EMUL_${MACHINE_ARCH}}
> .else
> LLD_EMUL =
> .endif
>

Oh that makes sense.

Index: arch-defines.mk
===================================================================
RCS file: /cvs/ports/infrastructure/mk/arch-defines.mk,v
retrieving revision 1.69
diff -u -p -u -1 -1 -r1.69 arch-defines.mk
--- arch-defines.mk 9 Nov 2019 15:08:09 -0000 1.69
+++ arch-defines.mk 4 Dec 2019 12:42:21 -0000
@@ -57,31 +57,36 @@ DEBUG_PACKAGES =
DEBUG_FILES =
.endif

.if ${PROPERTIES:Mclang}
LIBCXX = c++ c++abi pthread
LIBECXX = c++ c++abi pthread
.else
LIBCXX = stdc++ pthread
LIBECXX = estdc++>=17 pthread
.endif

-.if ${PROPERTIES:Mlld}
+.if ${PROPERTIES:Mlld} || defined(USE_LLD) && ${USE_LLD:L} == yes
# see llvm/tools/lld/ELF/Driver.cpp
-. for A in aarch64.aarch64elf amd64.elf_amd64 arm.armelf i386.elf_i386 \
- mips64.elf64btsmip mips64el.elf64ltsmip powerpc.elf32ppc \
- sparc64.elf64_sparc
-. if ${MACHINE_ARCH} == ${A:R}
-LLD_EMUL = -m${A:E}
-. endif
-. endfor
+_LLD_EMUL_aarch64 = aarch64elf
+_LLD_EMUL_amd64 = elf_amd64
+_LLD_EMUL_arm = armelf
+_LLD_EMUL_i386 = elf_i386
+_LLD_EMUL_mips64 = elf64btsmip
+_LLD_EMUL_mips64el = elf64ltsmip
+_LLD_EMUL_powerpc = elf32ppc
+_LLD_EMUL_sparc64 = elf64_sparc
+.endif
+
+.if defined(_LLD_EMUL_${MACHINE_ARCH})
+LLD_EMUL = -m${_LLD_EMUL_${MACHINE_ARCH}}
.else
LLD_EMUL =
.endif

# system version wide specifics
_SYSTEM_VERSION = 1
_SYSTEM_VERSION-aarch64 = 3
_SYSTEM_VERSION-amd64 = 4
_SYSTEM_VERSION-arm = 3
_SYSTEM_VERSION-i386 = 2
_SYSTEM_VERSION-mips64 = 1