[RFC] external compiler support

Thu Feb 28 06:02:51 UTC 2013

On Feb 27, 2013, at 5:02 PM, Brooks Davis wrote:

> On Wed, Feb 27, 2013 at 04:15:52PM -0600, Brooks Davis wrote:
>> On Wed, Feb 27, 2013 at 02:47:59PM -0700, Warner Losh wrote:
>>> 
>>> On Feb 27, 2013, at 2:44 PM, Brooks Davis wrote:
>>>>>> As a strawman, let's say we add a CROSS_COMPILER_PATH and a
>>>>>> CROSS_BINUTILS_PATH.  The former will set XCC, XCXX, and XCPP if they
>>>>>> are unset.  The latter will control -B and set the various binutils
>>>>>> variables (XNM, XLD, etc).
>>>>> 
>>>>> I'm not sure I like splitting things like that. It is unnatural.
>>>> 
>>>> That's the traditional view with lots of historic merit.  At least in
>>>> the short term it's not a useful view for me.  I want to be able to
>>>> use our existing infrastructure to build a cross binutils and then use
>>>> it with an external compiler.  In a clang world, we currently have one
>>>> compiler and many binutils unless we gratuitously build many compilers
>>>> as the FreeBSD build system currently does.  Some day we will likely have
>>>> an all-llvm toolchain available and then we will have one toolchain for
>>>> all supported architectures.
>>>> 
>>>> I suppose could hack what I want to do into the traditional single
>>>> toolchain world view by build a mips64 xdev toolchain and then building
>>>> a linkfarm and/or set of wrapper scripts to it and the clang I want to
>>>> include, but that seems problematic from a reproducability perspective
>>>> (not to mention performance if I need wrappers to set -B).
>>>> 
>>>> Having a CROSS_TOOLCHAIN_PATH path that sets both would probably be a
>>>> useful compromise in this regard.
>>> 
>>> Are you suggesting something like:
>>> 
>>> CROSS_COMPILER_PATH?=${CROSS_TOOLCHAIN_PATH}
>>> CROSS_BINUTILS_PATH?=${CROSS_TOOLCHAIN_PATH}
>>> 
>>> If so, I'd agree, that would be a very useful compromise: hits my ease of use issues, and lets you do what you need on the theory that others will likely need it too.
>> 
>> That's exactly what I'm thinking.
> 
> Here's a rework with that implemented.  I'm not 100% sure I got the list
> of binutils right, but it notionally supports both my usecase and a more
> classic cross compiler set.
> 
> -- Brooks
> 
> MFP4 222356, 222371, 222375, 222391, 222403, 222407, 222411, 222446
> 
> Add support for an external cross compiler.  The cross compiler is
> specified by passing the XCC, XCXX, and XCPP variables (corresponding to
> CC, CXX, and CPP) to buildworld/buildkernel.  The compiler must be clang
> or be configured to target the appropriate architecture.
> 
> To speed build times, if XCC is an absolute path or
> WITHOUT_CROSS_COMPILER is defined then no cross compiler will be built
> during the cross-tools stage.
> 
> To facilitate the use of unmodified external compilers, a
> WITHOUT_FORMAT_EXTENSIONS option is available to supress printf format
> checking.
> 
> As a short-term measure, supress a few new clang warnings during kernel
> builds.
> 
> Sponsored by:	DARPA, AFRL
> Reviewed by:	xxx

Looks a lot better, some minor comments..

> --- ../../freebsd/src/Makefile.inc1	2013-02-26 21:31:09.000000000 +0000
> +++ ./Makefile.inc1	2013-02-27 23:31:46.000000000 +0000
> @@ -280,15 +280,61 @@
> .if ${MK_CDDL} == "no"
> WMAKEENV+=	NO_CTF=1
> .endif
> -.if ${CC:T:Mgcc} == "gcc"
> +
> +.if defined(CROSS_TOOLCHAIN_PATH)
> +CROSS_COMPILER_PATH?=${CROSS_TOOLCHAIN_PATH}
> +CROSS_BINUTILS_PATH?=${CROSS_TOOLCHAIN_PATH}
> +.endif
> +XCOMPILERS=	CC CXX CPP
> +.for COMPILER in ${XCOMPILERS}
> +.if defined(CROSS_COMPILER_PATH)
> +X${COMPILER}?=	${CROSS_COMPILER_PATH}/${${COMPILER}}

This makes it harder to support FreeBSD make xdev-built compilers. Can you lose the / and require it to be specified if someone wants to use just a path?

> +.else
> +X${COMPILER}?=	${${COMPILER}}
> +.endif
> +.endfor
> +XBINUTILS=	AS AR LD NM OBJDUMP RANLIB STRINGS
> +.for BINUTIL in ${XBINUTILS}
> +.if defined(CROSS_BINUTILS_PATH)
> +X${BINUTIL}?=	${CROSS_BINUTILS_PATH}/${${BINUTIL}}

Same.

> +.else
> +X${BINUTIL}?=	${${BINUTIL}}
> +.endif
> +.endfor
> +WMAKEENV+=	CC="${XCC} ${XFLAGS}" CXX="${XCXX} ${XFLAGS}" \
> +		CPP="${XCPP} ${XFLAGS}" \
> +		AS="${XAS}" AR="${XAR}" LD="${XLD}" NM=${XNM} \
> +		OBJDUMP=${XOBJDUMP} RANLIB=${RANLIB} STRINGS=${XSTRINGS}

XRANLIB maybe?

> +
> +.if ${XCC:T:Mgcc} == "gcc"
> WMAKE_COMPILER_TYPE=	gcc
> -.elif ${CC:T:Mclang} == "clang"
> +.elif ${XCC:T:Mclang} == "clang"
> WMAKE_COMPILER_TYPE=	clang
> .elif ${MK_CLANG_IS_CC} == "no"
> WMAKE_COMPILER_TYPE=	gcc
> .else
> WMAKE_COMPILER_TYPE=	clang
> .endif
> +
> +.if ${XCC:M/*}
> +XFLAGS=		--sysroot=${WORLDTMP}
> +.if defined(CROSS_BINUTILS_PATH)
> +XFLAGS+=	-B${CROSS_BINUTILS_PATH}

Hmmm, but this would need to change somehow...

> +.else
> +XFLAGS+=	-B${WORLDTMP}/usr/bin
> +.endif
> +.if ${TARGET_ARCH} != ${MACHINE_ARCH} && ${WMAKE_COMPILER_TYPE} == "clang"
> +.if (${TARGET_ARCH} == "arm" || ${TARGET_ARCH} == "armv6") && \
> +${MK_ARM_EABI} != "no"
> +TARGET_ABI=	gnueabi
> +.else
> +TARGET_ABI=	unknown
> +.endif
> +TARGET_TRIPLE?=	${TARGET_ARCH:C/amd64/x86_64/}-${TARGET_ABI}-freebsd10.0
> +XFLAGS+=	-target ${TARGET_TRIPLE}
> +.endif
> +.endif
> +
> WMAKEENV+=	COMPILER_TYPE=${WMAKE_COMPILER_TYPE}
> WMAKE=		${WMAKEENV} ${MAKE} ${WORLD_FLAGS} -f Makefile.inc1 DESTDIR=${WORLDTMP}
> 
> @@ -321,6 +367,7 @@
> 
> 
> LIB32FLAGS=	-m32 ${LIB32CPUFLAGS} -DCOMPAT_32BIT \
> +		--sysroot=${WORLDTMP} \
> 		-isystem ${LIB32TMP}/usr/include/ \
> 		-L${LIB32TMP}/usr/lib32 \
> 		-B${LIB32TMP}/usr/lib32
> @@ -336,8 +383,8 @@
> 		SHLIBDIR=/usr/lib32 \
> 		COMPILER_TYPE=${WMAKE_COMPILER_TYPE}
> LIB32WMAKEFLAGS+=	\
> -		CC="${CC} ${LIB32FLAGS}" \
> -		CXX="${CXX} ${LIB32FLAGS}" \
> +		CC="${XCC} ${LIB32FLAGS}" \
> +		CXX="${XCXX} ${LIB32FLAGS}" \
> 		DESTDIR=${LIB32TMP} \
> 		-DCOMPAT_32BIT \
> 		-DLIBRARIES_ONLY \
> @@ -1284,10 +1331,13 @@
> .endif
> .endif
> 
> -.if ${MK_BINUTILS} != "no"
> +.if ${XAS:M/*} == "" && ${MK_BINUTILS} != "no"
> _binutils=	gnu/usr.bin/binutils
> .endif
> 
> +# If an full path to an external cross compiler is given, don't build
> +# a cross compiler.
> +.if ${XCC:M/*} == "" && ${MK_CROSS_COMPILER} != "no"
> .if ${MK_CLANG} != "no" && (${MK_CLANG_IS_CC} != "no" || ${CC:T:Mclang} == "clang")
> _clang=		usr.bin/clang
> _clang_libs=	lib/clang
> @@ -1296,6 +1346,7 @@
> .if ${MK_GCC} != "no" && (${MK_CLANG_IS_CC} == "no" || ${TARGET} == "pc98")
> _cc=		gnu/usr.bin/cc
> .endif
> +.endif
> 
> cross-tools:
> .for _tool in \
> --- ../../freebsd/src/share/mk/bsd.own.mk	2013-02-15 18:49:13.000000000 +0000
> +++ share/mk/bsd.own.mk	2013-02-26 21:10:50.000000000 +0000
> @@ -262,6 +262,7 @@
>     CAPSICUM \
>     CDDL \
>     CPP \
> +    CROSS_COMPILER \
>     CRYPT \
>     CTM \
>     CVS \
> @@ -271,6 +272,7 @@
>     ED_CRYPTO \
>     EXAMPLES \
>     FLOPPY \
> +    FORMAT_EXTENSIONS \
>     FORTH \
>     FP_LIBC \
>     FREEBSD_UPDATE \
> --- ../../freebsd/src/sys/conf/kern.mk	2012-11-11 22:15:16.000000000 +0000
> +++ sys/conf/kern.mk	2013-02-26 20:35:48.000000000 +0000
> @@ -5,7 +5,7 @@
> #
> CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
> 		-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
> -		-Wundef -Wno-pointer-sign -fformat-extensions \
> +		-Wundef -Wno-pointer-sign ${FORMAT_EXTENTIONS} \
> 		-Wmissing-include-dirs -fdiagnostics-show-option \
> 		${CWARNEXTRA}
> #
> @@ -29,7 +29,18 @@
> # enough to error out the whole kernel build.  Display them anyway, so there is
> # some incentive to fix them eventually.
> CWARNEXTRA?=	-Wno-error-tautological-compare -Wno-error-empty-body \
> -		-Wno-error-parentheses-equality
> +		-Wno-error-parentheses-equality \
> +		-Wno-sizeof-pointer-memaccess \
> +		-Wno-unused-command-line-argument \
> +		${NO_WFORMAT}
> +.endif
> +
> +# External compilers may not support our format extensions.  Allow them
> +# to be disabled.  WARNING: format checking is disabled in this case.
> +.if ${MK_FORMAT_EXTENSIONS} == "no"
> +NO_WFORMAT=		-Wno-format
> +.else
> +FORMAT_EXTENTIONS=	-fformat-extensions
> .endif
> 
> #
> diff -uN ../../freebsd/src/tools/build/options/WITHOUT_CROSS_COMPILER tools/build/options/WITHOUT_CROSS_COMPILER
> --- ../../freebsd/src/tools/build/options/WITHOUT_CROSS_COMPILER	1970-01-01 00:00:00.000000000 +0000
> +++ tools/build/options/WITHOUT_CROSS_COMPILER	2013-02-26 21:10:50.000000000 +0000
> @@ -0,0 +1,3 @@
> +.\" $FreeBSD$
> +Set to not build a cross compiler in the cross-tools stage of
> +buildworld, buildkernel, etc.
> diff -uN ../../freebsd/src/tools/build/options/WITHOUT_FORMAT_EXTENSIONS tools/build/options/WITHOUT_FORMAT_EXTENSIONS
> --- ../../freebsd/src/tools/build/options/WITHOUT_FORMAT_EXTENSIONS	1970-01-01 00:00:00.000000000 +0000
> +++ tools/build/options/WITHOUT_FORMAT_EXTENSIONS	2013-02-26 20:35:48.000000000 +0000
> @@ -0,0 +1,5 @@
> +.\" $FreeBSD$
> +Set to not enable
> +.Fl fformat-extensions
> +when compiling the kernel.
> +Also disables all format checking.