Date: Wed, 27 Feb 2013 08:57:14 -0700 From: Warner Losh <imp@bsdimp.com> To: Brooks Davis <brooks@FreeBSD.org> Cc: freebsd-arch@freebsd.org Subject: Re: [RFC] external compiler support Message-ID: <28404C12-67F3-44F0-AB28-02B749472873@bsdimp.com> In-Reply-To: <20130227003517.GB7348@lor.one-eyed-alien.net> References: <20130227003517.GB7348@lor.one-eyed-alien.net>
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On Feb 26, 2013, at 5:35 PM, Brooks Davis wrote: > Below (and at http://people.freebsd.org/~brooks/patches/xcc.diff) you > can find an initial patch with proposed commit for external compiler > support. It relies on the existing cross binutils as I'm finding that > the two are fairly separable. With this patch I've been able to build > from amd64 to arm, amd64, and i386 using clang from the = lang/clang-devel > port. I've also compiled the tree with a customized clang being > developed at the University of Cambridge. Cool! > The patch is untested with gcc. I'd like to see it tested with gcc :) > Does this seem like a reasonable approach? I do plan to look at = external > binutils support, but it's not on the critical path for our current = work > so I've opted to avoid it for now. The patches I posted a few months ago had that as well... > As a bonus for those who don't need an external compiler, but do run > make buildworld frequently, the XCC, XCXX, and XCPP variables can be = set > to the location of the installed base system compiler to avoid = building > the compiler twice during buildworld. I think this will work, but it is kludgy. I had created a = __X=3D<prefix-path> which was prepended to ${CC}, et al, in sys.mk. It = was only defined when you set CROSS_COMPILER_PATH (or = EXTERNAL_COMPILER_PATH, I forget) during the cross building stage. It = also had the advantage of making external cross binutils available. Your = patch could fairly easily use this interface instead of having to set 3 = different variables, which will morph to 10 when you add binutil = support. > -- Brooks >=20 > ----- > MFP4 222356, 222371, 222375, 222391, 222403, 222407, 222411 >=20 > 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. >=20 > 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. This change is likely good as-is. > To facilitate the use of unmodified external compilers, a > WITHOUT_FORMAT_EXTENSIONS option is available to supress printf format > checking. This one definitely is good as-is. > As a short-term measure, supress a few new clang warnings during = kernel > builds. >=20 > Sponsored by: DARPA, AFRL > Reviewed by: xxx >=20 > --- ../../freebsd/src/Makefile.inc1 2013-02-26 21:31:09.000000000 = +0000 > +++ ./Makefile.inc1 2013-02-26 21:10:50.000000000 +0000 > @@ -280,16 +280,34 @@ > .if ${MK_CDDL} =3D=3D "no" > WMAKEENV+=3D NO_CTF=3D1 > .endif > -.if ${CC:T:Mgcc} =3D=3D "gcc" > +XCC?=3D ${CC} > +XCXX?=3D ${CXX} > +XCPP?=3D ${CPP} I don't like having three different variables to set. I don't think this = will work with gcc, unless we've fixed all the instances in the tree = where we called AS or LD directly. The patches that I had would set = ${CC}, etc based on a CROSS_COMPILER_PATH=3Dxxx variable. I'd rather see = us do that than have this hacky set 3 variables thing. > +.if ${XCC:T:Mgcc} =3D=3D "gcc" > WMAKE_COMPILER_TYPE=3D gcc > -.elif ${CC:T:Mclang} =3D=3D "clang" > +.elif ${XCC:T:Mclang} =3D=3D "clang" > WMAKE_COMPILER_TYPE=3D clang > .elif ${MK_CLANG_IS_CC} =3D=3D "no" > WMAKE_COMPILER_TYPE=3D gcc > .else > WMAKE_COMPILER_TYPE=3D clang > .endif Is there any way to set the WMAKE_COMPILER_TYPE with these patches? XCC = might be something like mips-cavium-cc which won't trigger any of the = above, unless you also have set WITHOUT_CLANG_IS_CC... > -WMAKEENV+=3D COMPILER_TYPE=3D${WMAKE_COMPILER_TYPE} > +.if ${XCC:M/*} > +XFLAGS=3D --sysroot=3D${WORLDTMP} -B${WORLDTMP}/usr/bin > +.if ${TARGET_ARCH} !=3D ${MACHINE_ARCH} && ${WMAKE_COMPILER_TYPE} =3D=3D= "clang" > +.if (${TARGET_ARCH} =3D=3D "arm" || ${TARGET_ARCH} =3D=3D "armv6") && = \ > +${MK_ARM_EABI} !=3D "no" > +TARGET_ABI=3D gnueabi > +.else > +TARGET_ABI=3D unknown > +.endif We need to fix the gnueabi issue with arm. machine_arch should always = be enough to be self-hosting, and while I fixed the armv6 issue, this = has cropped up in its place :(. > +TARGET_TRIPLE?=3D = ${TARGET_ARCH:C/amd64/x86_64/}-${TARGET_ABI}-freebsd10.0 > +XFLAGS+=3D -target ${TARGET_TRIPLE} > +.endif > +.endif > +WMAKEENV+=3D CC=3D"${XCC} ${XFLAGS}" CXX=3D"${XCXX} ${XFLAGS}" \ > + CPP=3D"${XCPP} ${XFLAGS}" \ > + COMPILER_TYPE=3D${WMAKE_COMPILER_TYPE} > WMAKE=3D ${WMAKEENV} ${MAKE} ${WORLD_FLAGS} -f = Makefile.inc1 DESTDIR=3D${WORLDTMP} >=20 > .if ${TARGET_ARCH} =3D=3D "amd64" || ${TARGET_ARCH} =3D=3D "powerpc64" > @@ -321,6 +339,7 @@ >=20 >=20 > LIB32FLAGS=3D -m32 ${LIB32CPUFLAGS} -DCOMPAT_32BIT \ > + --sysroot=3D${WORLDTMP} \ > -isystem ${LIB32TMP}/usr/include/ \ > -L${LIB32TMP}/usr/lib32 \ > -B${LIB32TMP}/usr/lib32 > @@ -336,8 +355,8 @@ > SHLIBDIR=3D/usr/lib32 \ > COMPILER_TYPE=3D${WMAKE_COMPILER_TYPE} > LIB32WMAKEFLAGS+=3D \ > - CC=3D"${CC} ${LIB32FLAGS}" \ > - CXX=3D"${CXX} ${LIB32FLAGS}" \ > + CC=3D"${XCC} ${LIB32FLAGS}" \ > + CXX=3D"${XCXX} ${LIB32FLAGS}" \ > DESTDIR=3D${LIB32TMP} \ > -DCOMPAT_32BIT \ > -DLIBRARIES_ONLY \ > @@ -1288,6 +1307,9 @@ > _binutils=3D gnu/usr.bin/binutils > .endif >=20 > +# If an full path to an external cross compiler is given, don't build > +# a cross compiler. > +.if ${XCC:M/*} =3D=3D "" && ${MK_CROSS_COMPILER} !=3D "no" > .if ${MK_CLANG} !=3D "no" && (${MK_CLANG_IS_CC} !=3D "no" || = ${CC:T:Mclang} =3D=3D "clang") > _clang=3D usr.bin/clang > _clang_libs=3D lib/clang > @@ -1296,6 +1318,7 @@ > .if ${MK_GCC} !=3D "no" && (${MK_CLANG_IS_CC} =3D=3D "no" || ${TARGET} = =3D=3D "pc98") > _cc=3D gnu/usr.bin/cc > .endif > +.endif >=20 > 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?=3D -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?=3D -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} =3D=3D "no" > +NO_WFORMAT=3D -Wno-format > +.else > +FORMAT_EXTENTIONS=3D -fformat-extensions > .endif >=20 > # > 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.
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