Here is my current diff to build clang alongside gcc. The idea is
that if you add an architecture to both CLANG_ARCH and GCC4_ARCH, both
compilers get built, but gcc remains the default compiler. It forces
the clang-related libraries (libcompiler_rt, libc++abi, libc++) to be
built with clang.
You'll need to bootstrap clang with the ports gcc before you can do a
make build. This is done using:
# pkg_add g++
# cd /usr/src/gnu/usr.bin/clang
# make obj
# make BOOTSTRAP_CLANG=yes
# make install
Thoughts? ok? If we don't want to start building clang on amd64 just
yet, I can leave GCC4_ARCHS empty for now.
Index: gnu/usr.bin/Makefile
===================================================================
RCS file: /cvs/src/gnu/usr.bin/Makefile,v
retrieving revision 1.58
diff -u -p -r1.58 Makefile
--- gnu/usr.bin/Makefile 20 Feb 2017 01:00:26 -0000 1.58
+++ gnu/usr.bin/Makefile 15 Apr 2017 12:06:10 -0000
@@ -10,7 +10,8 @@ SUBDIR+= cc clang gcc
SUBDIR+= gcc
. elif ${COMPILER_VERSION:L} == "gcc4"
SUBDIR+= cc
-. elif ${COMPILER_VERSION:L} == "clang"
+. endif
+. if ${BUILD_CLANG} == "yes"
SUBDIR+= clang
. endif
.endif
Index: gnu/usr.bin/clang/Makefile.inc
===================================================================
RCS file: /cvs/src/gnu/usr.bin/clang/Makefile.inc,v
retrieving revision 1.4
diff -u -p -r1.4 Makefile.inc
--- gnu/usr.bin/clang/Makefile.inc 16 Feb 2017 02:08:42 -0000 1.4
+++ gnu/usr.bin/clang/Makefile.inc 27 Mar 2017 15:56:49 -0000
@@ -2,6 +2,11 @@
LLVM_SRCS?= ${.CURDIR}/../../../llvm
+.if ${COMPILER_VERSION:L} != "clang"
+CC= clang
+CXX= clang++
+.endif
+
BOOTSTRAP_CLANG?=no
.if ${BOOTSTRAP_CLANG} == "yes"
CC= egcc
Index: lib/libcompiler_rt/Makefile
===================================================================
RCS file: /cvs/src/lib/libcompiler_rt/Makefile,v
retrieving revision 1.6
diff -u -p -r1.6 Makefile
--- lib/libcompiler_rt/Makefile 9 Apr 2017 21:47:05 -0000 1.6
+++ lib/libcompiler_rt/Makefile 15 Apr 2017 12:14:38 -0000
@@ -2,7 +2,12 @@
.include <bsd.own.mk>
-.if ${COMPILER_VERSION:L} == "clang"
+.if ${COMPILER_VERSION:L} != "clang"
+CC= clang
+CXX= clang++
+.endif
+
+.if ${BUILD_CLANG} == "yes"
LIB= compiler_rt
NOPIC=
Index: lib/libcxx/Makefile
===================================================================
RCS file: /cvs/src/lib/libcxx/Makefile,v
retrieving revision 1.5
diff -u -p -r1.5 Makefile
--- lib/libcxx/Makefile 16 Feb 2017 02:08:42 -0000 1.5
+++ lib/libcxx/Makefile 15 Apr 2017 12:04:11 -0000
@@ -2,7 +2,12 @@
.include <bsd.own.mk>
-.if ${COMPILER_VERSION:L} == "clang"
+.if ${COMPILER_VERSION:L} != "clang"
+CC= clang
+CXX= clang++
+.endif
+
+.if ${BUILD_CLANG} == "yes"
HDRDIR= ${.CURDIR}/include
SRCDIR= ${.CURDIR}/src
Index: lib/libcxxabi/Makefile
===================================================================
RCS file: /cvs/src/lib/libcxxabi/Makefile,v
retrieving revision 1.7
diff -u -p -r1.7 Makefile
--- lib/libcxxabi/Makefile 6 Apr 2017 09:28:29 -0000 1.7
+++ lib/libcxxabi/Makefile 15 Apr 2017 12:00:40 -0000
@@ -2,7 +2,12 @@
.include <bsd.own.mk>
-.if ${COMPILER_VERSION:L} == "clang"
+.if ${COMPILER_VERSION:L} != "clang"
+CC= clang
+CXX= clang++
+.endif
+
+.if ${BUILD_CLANG} == "yes"
HDRDIR= ${.CURDIR}/include
SRCDIR= ${.CURDIR}/src
Index: share/mk/bsd.own.mk
===================================================================
RCS file: /cvs/src/share/mk/bsd.own.mk,v
retrieving revision 1.182
diff -u -p -r1.182 bsd.own.mk
--- share/mk/bsd.own.mk 18 Dec 2016 17:02:21 -0000 1.182
+++ share/mk/bsd.own.mk 15 Apr 2017 11:58:41 -0000
@@ -15,7 +15,8 @@ SKEY?= yes
# Set `YP' to `yes' to build with support for NIS/YP.
YP?= yes
-CLANG_ARCH=aarch64
+CLANG_ARCH=aarch64 amd64
+GCC4_ARCH=amd64
GCC3_ARCH=m88k
# m88k: ?
@@ -23,12 +24,20 @@ PIE_ARCH=alpha amd64 arm hppa i386 mips6
STATICPIE_ARCH=alpha amd64 arm hppa i386 mips64 mips64el powerpc sh sparc64
.for _arch in ${MACHINE_ARCH}
-.if !empty(CLANG_ARCH:M${_arch})
-COMPILER_VERSION?=clang
-.elif !empty(GCC3_ARCH:M${_arch})
+.if !empty(GCC3_ARCH:M${_arch})
COMPILER_VERSION?=gcc3
+.elif !empty(GCC4_ARCH:M${_arch})
+COMPILER_VERSION?=gcc4
+.elif !empty(CLANG_ARCH:M${_arch})
+COMPILER_VERSION?=clang
.else
COMPILER_VERSION?=gcc4
+.endif
+
+.if !empty(CLANG_ARCH:M${_arch})
+BUILD_CLANG?=yes
+.else
+BUILD_CLANG?=no
.endif
.if !empty(STATICPIE_ARCH:M${_arch})
