Re: C++ in jemalloc

Warner Losh imp at bsdimp.com wrote on
Thu Oct 5 21:01:26 UTC 2017 :

> Starting in FreeBSD 11, arm and powerpc are supported by clang,
> but not super well. For FreeBSD 12, we're getting close for everything
> except sparc64 (whose fate has not yet been finally decided).

My understanding of the powerpc and powerpc64 status
follows. This is based on my use of head via clang
as much as I can for them.

For TARGET_ARCH=powerpc64 and TARGET_ARCH=powerpc :

lld is far from working last I knew. (I've focused
more on the compilers for testing, using other
linkers and such.) [lldb may be in a similar state
for powerpc64. It does not build for powerpc.]

clang 5 (and 4) generated code crashes on any thrown
C++ exception. For example:

#include <exception>

int main(void)
{
    try { throw std::exception(); }
    catch (std::exception& e) {}
    return 0;
}

crashes.

Luckily most kernel and world code that I actively use
does not throw C++ exceptions in my use.

But devel/kyua is majorly broken by the C++ exception
issue: It makes extensive use of C++ exceptions. In my
view that disqualifies clang as being "close": I view
my activity as a hack until devel/kyua is generally
operable and so available for use in testing.

clang 5 currently can not build the TARGET_ARCH=powerpc
kernel. (I was able to back in clang 4 days --but the
resultant build failed to execute init fully after
finishing the prior boot activity.) For the 32-bit
context I use gcc 4.2.1 for building the kernel and
clang 5 for building the world, system binutils 
in use in both cases.

I do build the kernel and world for
TARGET_ARCH=powerpc64 via system clang 5. But I
use ports binutils as well in order for this to
finish and work overall.


As for more modern devel/powerpc64-xtoolchain-gcc
(so devel/powerpc64-gcc) versions being used to
build the world and kernel for powerpc64 I've never
been able to get lib32 on powerpc64 to work via
such a build: it builds but fails to execute from
dereferencing via an R30 that has an inappropriate
value for the attempt ( lib32/crtbeginS.o code in
_init in /usr/lib32/libc.so.* ). (The clang-based
builds do not have this problem.) It has been a
while since I've done devel/powerpc64-gcc
experiments.

I'm not aware of a devel/powerpc-xtoolchain-gcc
as an alternative for 32-bit powerpc targeting.


You may want to skip the below src.conf's
and so reading the rest of this note.

Example src.conf for targeting powerpc64 for
buildkernel and buildworld via clang:

(Note: most of my more recent activity has cross
built from amd64 instead of doing self-hosted.
That way more folks can try the same for
issues where builds stop.)

# more ~/src.configs/src.conf.powerpc64-clang_altbinutils-bootstrap.amd64-host
TO_TYPE=powerpc64
TOOLS_TO_TYPE=${TO_TYPE}
VERSION_CONTEXT=12.0
#
KERNCONF=GENERIC64vtsc-NODBG
TARGET=powerpc
.if ${.MAKE.LEVEL} == 0
TARGET_ARCH=${TO_TYPE}
.export TARGET_ARCH
.endif
#
WITH_CROSS_COMPILER=
WITHOUT_SYSTEM_COMPILER=
#
WITH_LIBCPLUSPLUS=
WITHOUT_BINUTILS_BOOTSTRAP=
WITH_ELFTOOLCHAIN_BOOTSTRAP=
WITH_CLANG_BOOTSTRAP=
WITH_CLANG=
WITH_CLANG_IS_CC=
WITH_CLANG_FULL=
WITH_CLANG_EXTRAS=
WITHOUT_LLD_BOOTSTRAP=
WITH_LLD=
WITHOUT_LLD_IS_LD=
WITH_LLDB=
#
WITH_BOOT=
WITH_LIB32=
#
WITHOUT_GCC_BOOTSTRAP=
WITHOUT_GCC=
WITHOUT_GCC_IS_CC=
WITHOUT_GNUCXX=
#
NO_WERROR=
MALLOC_PRODUCTION=
#
# Avoid converts between pointers to integer types with different sign [-Werror,-Wpointer-sign]
# and such from blocking the build.
WERROR=
#
WITH_REPRODUCIBLE_BUILD=
WITH_DEBUG_FILES=
#
#
# For TO (so-called "cross") stages . . .
# So-called-cross via ${TO_TYPE}-xtoolchain-gcc/${TO_TYPE}-gcc. . .
# TOOLS_TO_TYPE based on ${TO_TYPE}-xtoolchain-gcc related binutils. . .
#
CROSS_BINUTILS_PREFIX=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/
.if ${.MAKE.LEVEL} == 0
#
# Note: The WITH_CROSS_COMPILER picks up the CROSS_BINUTILS_PREFIX
#       binding automatically.
#
XAS=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/as
XAR=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ar
XNM=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/nm
XOBJCOPY=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/objcopy
XOBJDUMP=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/objdump
XRANLIB=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ranlib
XSIZE=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/size
#NO-SUCH: XSTRINGS=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/strings
XSTRINGS=/usr/local/bin/${TOOLS_TO_TYPE}-freebsd-strings
.export XAS
.export XAR
.export XNM
.export XOBJCOPY
.export XOBJDUMP
.export XRANLIB
.export XSIZE
.export XSTRINGS
XLD=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ld
.export XLD
.endif


For powerpc via clang (world anyway):

# more ~/src.configs/src.conf.powerpc-clang-bootstrap.amd64-host
TO_TYPE=powerpc
#
KERNCONF=GENERICvtsc-NODBG
TARGET=${TO_TYPE}
.if ${.MAKE.LEVEL} == 0
TARGET_ARCH=${TO_TYPE}
.export TARGET_ARCH
.endif
#
WITH_CROSS_COMPILER=
WITHOUT_SYSTEM_COMPILER=
#
WITH_LIBCPLUSPLUS=
WITH_BINUTILS_BOOTSTRAP=
WITH_ELFTOOLCHAIN_BOOTSTRAP=
WITH_CLANG_BOOTSTRAP=
WITH_CLANG=
WITH_CLANG_IS_CC=
WITH_CLANG_FULL=
WITH_CLANG_EXTRAS=
WITHOUT_LLD=
# lldb requires missing atomic 8-byte operations for powerpc (non-64)
WITHOUT_LLDB=
#
WITH_BOOT=
WITHOUT_LIB32=
#
WITHOUT_GCC_BOOTSTRAP=
WITHOUT_GCC=
WITHOUT_GCC_IS_CC=
WITHOUT_GNUCXX=
#
NO_WERROR=
#
# Use WERROR to avoid stopping at the likes of:
# error: implicit conversion from 'int' to 'int8_t' (aka 'signed char') changes value from 128 to -128 [-Werror,-Wconstant-conversion]
WERROR=
MALLOC_PRODUCTION=
#
WITH_REPRODUCIBLE_BUILD=
WITH_DEBUG_FILES=


As for powerpc64-xtoolchain-gcc
targeting powerpc64:

# more ~/src.configs/src.conf.powerpc64-xtoolchain-gcc.amd64-host
TO_TYPE=powerpc64
TOOLS_TO_TYPE=${TO_TYPE}
VERSION_CONTEXT=12.0
#
KERNCONF=GENERIC64vtsc-NODBG
TARGET=powerpc
.if ${.MAKE.LEVEL} == 0
TARGET_ARCH=${TO_TYPE}
.export TARGET_ARCH
.endif
#
WITHOUT_CROSS_COMPILER=
WITHOUT_SYSTEM_COMPILER=
#
WITH_LIBCPLUSPLUS=
WITHOUT_BINUTILS_BOOTSTRAP=
WITHOUT_ELFTOOLCHAIN_BOOTSTRAP=
WITHOUT_CLANG_BOOTSTRAP=
WITH_CLANG=
WITH_CLANG_IS_CC=
WITH_CLANG_FULL=
WITH_CLANG_EXTRAS=
WITH_LLD=
WITH_LLDB=
#
WITH_BOOT=
# powerpc64 LIB32 builds via gcc 4.9 or later variants that I've tried
# but the LIB32 does not work [crtbeginS code problem(s)]
WITHOUT_LIB32=
#
WITHOUT_GCC_BOOTSTRAP=
WITHOUT_GCC=
WITHOUT_GCC_IS_CC=
WITHOUT_GNUCXX=
#
NO_WERROR=
#
# Avoid db_trace.o getting:
#   calling '__builtin_frame_address' with a nonzero argument is unsafe
# as an error? Other such points as well.
WERROR=
MALLOC_PRODUCTION=
#
WITH_REPRODUCIBLE_BUILD=
WITH_DEBUG_FILES=
#
#
# For TO (so-called "cross") stages . . .
# So-called-cross via ${TO_TYPE}-xtoolchain-gcc/${TO_TYPE}-gcc. . .
# TOOLS_TO_TYPE based on ${TO_TYPE}-xtoolchain-gcc related binutils. . .
#
CROSS_TOOLCHAIN=${TO_TYPE}-gcc
X_COMPILER_TYPE=gcc
CROSS_BINUTILS_PREFIX=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/
.if ${.MAKE.LEVEL} == 0
XCC=/usr/local/bin/${TOOLS_TO_TYPE}-unknown-freebsd${VERSION_CONTEXT}-gcc
XCXX=/usr/local/bin/${TOOLS_TO_TYPE}-unknown-freebsd${VERSION_CONTEXT}-g++
XCPP=/usr/local/bin/${TOOLS_TO_TYPE}-unknown-freebsd${VERSION_CONTEXT}-cpp
.export XCC
.export XCXX
.export XCPP
XAS=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/as
XAR=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ar
XLD=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ld
XNM=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/nm
XOBJCOPY=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/objcopy
XOBJDUMP=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/objdump
XRANLIB=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/ranlib
XSIZE=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/size
#NO-SUCH: XSTRINGS=/usr/local/${TOOLS_TO_TYPE}-freebsd/bin/strings
XSTRINGS=/usr/local/bin/${TOOLS_TO_TYPE}-freebsd-strings
.export XAS
.export XAR
.export XLD
.export XNM
.export XOBJCOPY
.export XOBJDUMP
.export XRANLIB
.export XSIZE
.export XSTRINGS
.endif
#
#
# From based on clang (via system). . .
#
.if ${.MAKE.LEVEL} == 0
CC=/usr/bin/clang
CXX=/usr/bin/clang++
CPP=/usr/bin/clang-cpp
.export CC
.export CXX
.export CPP
.endif



===
Mark Millard
markmi_at_dsl-only.net