This is not the right one. That is related to clang 3.4. The issue is
that clang 3.5+ require a C++11 compiler to build. GCC 4.2 is not a
C++11 compiler and so the clang build was disabled. This makes the
upgrade path when clang becomes the default compiler a little bumpy, but
that did not seem to be a reason to hold off on the 3.5 upgrade across
the board.
-Nathan
On 03/12/15 10:01, Mark Millard wrote:
Well there is an entry but when I read it I did not find it clear about the
10.x status.
I think the implication is that the 9.x paragraph also applies to 10.x:
On 9.x [and 10.x] installations where clang is enabled by default,
e.g. on x86 and
powerpc, libc++ will not be enabled by default, so libc++ should be
built (with clang) and installed first. If both clang and libc++ are
missing, build clang first, then use it to build libc++.
===
Mark Millard
mar...@dsl-only.net
On 2015-Mar-12, at 05:00 AM, Warner Losh <i...@bsdimp.com> wrote:
On Mar 12, 2015, at 6:36 PM, Mark Millard <mar...@dsl-only.net> wrote:
Basic context for the observation (powerpc64 example):
# freebsd-version -ku; uname -a
11.0-CURRENT
11.0-CURRENT
FreeBSD FBSDG5C0 11.0-CURRENT FreeBSD 11.0-CURRENT #0 r279514M: Wed Mar 11
19:23:14 PDT 2015
root@FBSDG4C0:/usr/obj/powerpc.powerpc64/usr/srcC/sys/GENERIC64vtsc-NODEBUG
powerpc
As COMPILER_FEATURES context first I note that bsd.compiler.mk uses the rule...
.if ${COMPILER_TYPE} == "clang" || \
(${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 40800)
COMPILER_FEATURES= c++11
.else
COMPILER_FEATURES=
.endif
So powerpc/powerpc64 ends up with COMPILER_FEATURES being empty unless COMPILER_TYPE has
been forced to be "clang" or ${CC} already is clang based.
But src.opts.mk will never indicate to build clang when
!${COMPILER_FEATURES:Mc++11} : that logic has priority over things like
${__T:Mpowerpc*} tests…
Clang can only be built by a new gcc or clang. Old gcc can’t build it, so if
you don’t have a new gcc, you can’t build clang. The default compiler was gcc
on 10.1. There likely should be an UPDATING entry to make this clear.
Warner
.include <bsd.compiler.mk>
.if !${COMPILER_FEATURES:Mc++11}
# If the compiler is not C++11 capable, disable clang and use gcc instead.
__DEFAULT_YES_OPTIONS+=GCC GCC_BOOTSTRAP GNUCXX
__DEFAULT_NO_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_FULL CLANG_IS_CC
.elif ${__T} == "amd64" || ${__T} == "i386"
# On x86, clang is enabled, and will be installed as the default cc.
__DEFAULT_YES_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_FULL CLANG_IS_CC
__DEFAULT_NO_OPTIONS+=GCC GCC_BOOTSTRAP GNUCXX
.elif ${__TT} == "arm" && ${__T:Marm*eb*} == ""
# On little-endian arm, clang is enabled, and it is installed as the default
# cc, but since gcc is unable to build the full clang, disable it by default.
__DEFAULT_YES_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_IS_CC
__DEFAULT_NO_OPTIONS+=CLANG_FULL GCC GCC_BOOTSTRAP GNUCXX
.elif ${__T:Mpowerpc*}
# On powerpc, clang is enabled, but gcc is installed as the default cc.
__DEFAULT_YES_OPTIONS+=CLANG CLANG_FULL GCC GCC_BOOTSTRAP GNUCXX
__DEFAULT_NO_OPTIONS+=CLANG_BOOTSTRAP CLANG_IS_CC
.else
# Everything else disables clang, and uses gcc instead.
__DEFAULT_YES_OPTIONS+=GCC GCC_BOOTSTRAP GNUCXX
__DEFAULT_NO_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_FULL CLANG_IS_CC
.endif
By contrast the old bsd.own.mk logic from 10.1-STABLE did not depend on testing
!${COMPILER_FEATURES:Mc++11} (or analogous) before deciding for
powerpc/powerpc64...
# Clang is only for x86, powerpc and little-endian arm right now, by default.
.if ${__T} == "amd64" || ${__T} == "i386" || ${__T:Mpowerpc*}
__DEFAULT_YES_OPTIONS+=CLANG CLANG_FULL
.elif ${__T} == "arm" || ${__T} == "armv6"
__DEFAULT_YES_OPTIONS+=CLANG
# GCC is unable to build the full clang on arm, disable it by default.
__DEFAULT_NO_OPTIONS+=CLANG_FULL
.else
__DEFAULT_NO_OPTIONS+=CLANG CLANG_FULL
.endif
# Clang the default system compiler only on little-endian arm and x86.
.if ${__T} == "amd64" || ${__T} == "arm" || ${__T} == "armv6" || \
${__T} == "i386"
__DEFAULT_YES_OPTIONS+=CLANG_IS_CC
# The pc98 bootloader requires gcc to build and so we must leave gcc enabled
# for pc98 for now.
.if ${__TT} == "pc98"
__DEFAULT_NO_OPTIONS+=GNUCXX
__DEFAULT_YES_OPTIONS+=GCC
.else
__DEFAULT_NO_OPTIONS+=GCC GNUCXX
.endif
.else
# If clang is not cc, then build gcc by default
__DEFAULT_NO_OPTIONS+=CLANG_IS_CC
__DEFAULT_YES_OPTIONS+=GCC
# And if g++ is c++, build the rest of the GNU C++ stack
.if defined(WITHOUT_CXX)
__DEFAULT_NO_OPTIONS+=GNUCXX
.else
__DEFAULT_YES_OPTIONS+=GNUCXX
.endif
.endif
===
Mark Millard
markmi at dsl-only.net
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