FreeBSD aarch64 buildworld target fails to build 32-bit compat LLVM compiler-rt due to fp support

Rahul Rameshbabu <[email protected]>
Newsgroups gmane.os.freebsd.devel.arm
Message-ID <[email protected]> 
Hello,

I am trying to build the FreeBSD project for aarch64 to better support
the Raspberry Pi 3 and Raspberry Pi 4 boards in the project.

  https://wiki.freebsd.org/arm/Raspberry%20Pi

I use the following build command (generic aarch64 target).

  make TARGET_ARCH=aarch64 SRCCONF=/dev/null __MAKE_CONF=/dev/null -j 32 buildworld

I notice the following error related to HW floating point support on
armv7 (32-bit arch) target that is compiled for compat/32-bit build purposes.

  --- fixunsdfsivfp.o ---
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunsdfsivfp.S:26:2: error: instruction requires: fp registers
  --- lshrdi3.o ---
  cc -march=armv7 -m32 -target armv7-unknown-freebsd15.0-gnueabihf  -DCOMPAT_LIBCOMPAT=\"32\"  -DCOMPAT_libcompat=\"32\"  -DCOMPAT_LIB32  --sysroot=/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp  -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/bin -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/lib32  -O2 -pipe -fno-common -target armv7-unknown-freebsd  -fpic -fvisibility=hidden -DVISIBILITY_HIDDEN -I/usr/src/contrib/llvm-project/libunwind/include -DEMIT_SYNC_ATOMICS -g -gz=zlib -MD  -MF.depend.lshrdi3.o -MTlshrdi3.o -std=gnu99 -Wno-format-zero-length -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wdate-time -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-parameter -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-sw--- fixunsdfsivfp.o ---
  vmov d7, r0, r1
  ^
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunsdfsivfp.S:27:2: error: instruction requires: double precision VFP VFP2
  vcvt.u32.f64 s15, d7
  ^
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunsdfsivfp.S:28:2: error: instruction requires: fp registers
  vmov r0, s15
  ^
  --- lshrti3.o ---
  --- lshrdi3.o ---
  itch-enum -Wno-knr-promoted-parameter  -Qunused-arguments    -c /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/lshrdi3.c -o lshrdi3.o
  --- fixunssfsivfp.o ---
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunssfsivfp.S:26:2: error: instruction requires: fp registers
  vmov s15, r0
  ^
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunssfsivfp.S:27:2: error: instruction requires: VFP2
  vcvt.u32.f32 s15, s15
  ^
  /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/fixunssfsivfp.S:28:2: error: instruction requires: fp registers
  vmov r0, s15
  ^
  --- moddi3.o ---
  --- modsi3.o ---
  --- lshrti3.o ---
  cc -march=armv7 -m32 -target armv7-unknown-freebsd15.0-gnueabihf  -DCOMPAT_LIBCOMPAT=\"32\"  -DCOMPAT_libcompat=\"32\"  -DCOMPAT_LIB32  --sysroot=/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp  -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/bin -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/lib32  -O2 -pipe -fno-common -target armv7-unknown-freebsd  -fpic -fvisibility=hidden -DVISIBILITY_HIDDEN -I/usr/src/contrib/llvm-project/libunwind/include -DEMIT_SYNC_ATOMICS -g -gz=zlib -MD  -MF.depend.lshrti3.o -MTlshrti3.o -std=gnu99 -Wno-format-zero-length -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wdate-time -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-parameter -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-sw--- moddi3.o ---
  cc -march=armv7 -m32 -target armv7-unknown-freebsd15.0-gnueabihf  -DCOMPAT_LIBCOMPAT=\"32\"  -DCOMPAT_libcompat=\"32\"  -DCOMPAT_LIB32  --sysroot=/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp  -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/bin -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/lib32  -O2 -pipe -fno-common -target armv7-unknown-freebsd  -fpic -fvisibility=hidden -DVISIBILITY_HIDDEN -I/usr/src/contrib/llvm-project/libunwind/include -DEMIT_SYNC_ATOMICS -g -gz=zlib -MD  -MF.depend.moddi3.o -MTmoddi3.o -std=gnu99 -Wno-format-zero-length -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wdate-time -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-parameter -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-swit--- lshrti3.o ---
  itch-enum -Wno-knr-promoted-parameter  -Qunused-arguments    -c /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/lshrti3.c -o lshrti3.o
  --- modsi3.o ---
  cc -march=armv7 -m32 -target armv7-unknown-freebsd15.0-gnueabihf -DCOMPAT_LIBCOMPAT=\"32\" -DCOMPAT_libcompat=\"32\" -DCOMPAT_LIB32 --sysroot=/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/bin -B/home/binary-eater/Documents/crochet/work/obj/usr/src/arm64.aarch64/tmp/usr/lib32 -O2 -pipe -fno-common -target armv7-unknown-freebsd  -fpic -fvisibility=hidden -DVISIBILITY_HIDDEN -I/usr/src/contrib/llvm-project/libunwind/include -DEMIT_SYNC_ATOMICS -g -gz=zlib -MD  -MF.depend.modsi3.o -MTmodsi3.o -std=gnu99 -Wno-format-zero-length -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wdate-time -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-parameter -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-switch-enu--- moddi3.o ---
  ch-enum -Wno-knr-promoted-parameter  -Qunused-arguments    -c /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/moddi3.c -o moddi3.o
  --- modsi3.o ---
  m -Wno-knr-promoted-parameter  -Qunused-arguments     -target armv7-unknown-freebsd   -c /usr/src/contrib/llvm-project/compiler-rt/lib/builtins/arm/modsi3.S -o modsi3.o
  --- fixunsdfsivfp.o ---
  *** [fixunsdfsivfp.o] Error code 1

  make[4]: stopped in /usr/src/lib/libcompiler_rt
  --- fixunssfsivfp.o ---
  *** [fixunssfsivfp.o] Error code 1

  make[4]: stopped in /usr/src/lib/libcompiler_rt
  2 errors

  make[4]: stopped in /usr/src/lib/libcompiler_rt

  make[3]: stopped in /usr/src
  --- lib/libgcc_eh__PL ---

  make[3]: stopped in /usr/src

  make[2]: stopped in /usr/src
          0.31 real         2.27 user         0.81 sys
  *** [build32] Error code 2

  make[1]: stopped in /usr/src
  1 error

  make[1]: stopped in /usr/src

  make: stopped in /usr/src

I believe this is due to a couple of parts in the build system where I
am not sure what the right solution would be.

In lib/libcompiler_rt/Makefile.inc:

  .for file in ${SRCF}
  .if ${MACHINE_CPUARCH} == "arm" && (!defined(CPUTYPE) || ${CPUTYPE:M*soft*} == "") \
      && exists(${CRTSRC}/${CRTARCH}/${file}vfp.S)
  SRCS+=		${file}vfp.S
  . elif exists(${CRTSRC}/${CRTARCH}/${file}.S)
  SRCS+=		${file}.S
  . else
  SRCS+=		${file}.c
  . endif
  .endfor

When 32-bit compat for aarch64 is compiled, the first conditional is
true and this leads to the vfp assembly variants under
contrib/llvm-project/compiler-rt/lib/builtins/arm being chosen as source
that needs to be assembled (but the compiler options seem to lack the
needed arguments for the specific fp register support needed for vfp).

I believe these options are determined by the following snippet in
share/mk/bsd.compat.mk.

  .elif ${COMPAT_ARCH} == "aarch64"
  HAS_COMPAT+=	32
  .if empty(LIB32CPUTYPE)
  LIB32CPUFLAGS=	-march=armv7
  .else
  LIB32CPUFLAGS=	-mcpu=${LIB32CPUTYPE}
  .endif

The problem here is that armv7 is selected for the arch but there is no
indication of vfp support, which leads to the error seen. I am not sure
what the ideal fix is (avoid using vfp built-in for 32-bit compat or
hack up the compat build to indicate 32-bit compat for aarch64 always
has HW fp support).

You can find the full logs here if needed.

  https://gist.github.com/Binary-Eater/1ced3c02530254e716c441ed77ce4d8c

--
Thanks,

Rahul Rameshbabu
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