Date: Thu, 12 Mar 2015 20:43:59 -0700 From: Mark Millard <markmi@dsl-only.net> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: freebsd-toolchain@freebsd.org, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: powerpc/powerpc64 11.0-CURRENT not building clang by default: src.opt.mk not equivalent to 10.1-STABLE bsd.own.mk on the issue Message-ID: <7E317915-DBBE-4BCF-B6DD-45F3F723B9AC@dsl-only.net> In-Reply-To: <7A17FBA1-9499-4862-83DF-1C4010D96003@dsl-only.net> References: <DBD1D803-FD36-490E-9661-5347CBD55D94@dsl-only.net> <B5B7E302-09E0-4E94-8251-ED08EB75D38E@bsdimp.com> <7A17FBA1-9499-4862-83DF-1C4010D96003@dsl-only.net>
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Nathan W. wrote:
> This is not the right one. That is related to clang 3.4. The issue is=20=
> that clang 3.5+ require a C++11 compiler to build. ...
The text that I quoted is from the 11.0-CURRENT UPDATING entry that =
starts with the non-FreeBSD-variant-specific 3.5.0 background =
information below. May be I originally should not have only extracted =
the material I thought fit best for being instructions for powerpc64 =
10.x: i.e., I should have given more context.
For future readers, quoting more UPDATING context this time...
> 20141231:
> Clang, llvm and lldb have been upgraded to 3.5.0 release.
>=20
> As of this release, a prerequisite for building clang, llvm =
and lldb is
> a C++11 capable compiler and C++11 standard library. This =
means that to
> be able to successfully build the cross-tools stage of =
buildworld, with
> clang as the bootstrap compiler, your system compiler or cross =
compiler
> should either be clang 3.3 or later, or gcc 4.8 or later, and =
your
> system C++ library should be libc++, or libdstdc++ from gcc =
4.8 or
> later.
The later FreeBSD-variants-specific material makes for a complicated to =
read entry for powerpc/powerpc64 10.x. Why? Paragraph by paragraph for =
the next couple of paragraphs that follow the above...
> On any standard FreeBSD 10.x or 11.x installation, where clang =
and
> libc++ are on by default (that is, on x86 or arm), this should =
work out
> of the box.
"where clang and libc++ are on by default": the libc++ part excludes =
powerpc/powerpc64 10.x. The 3.4.1 status for clang is not sufficient =
here, despite being after 3.3.
> On 9.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++.
The "9.x" wording above makes no mention of 10.x but powerpc/powerpc64 =
10.x also has clang without having libc++ enabled by default. (Nor the =
libcxxrt that libc++ requires.) The instructions from here seem to be =
the ones that would apply (and likely do for powerpc64 --but not for =
powerpc as stands, see later).
After that is 8.x, Sparc64, and mips notes that are not a match to the =
powerpc/powerpc64 10.x context --and embedded system notes about cross =
builds:
> On 8.x and earlier installations, upgrade to 9.x first, and =
then follow
> the instructions for 9.x above.
>=20
> Sparc64 and mips users are unaffected, as they still use gcc =
4.2.1 by
> default, and do not build clang.
>=20
> Many embedded systems are resource constrained, and will not =
be able to
> build clang in a reasonable time, or in some cases at all. In =
those
> cases, cross building bootable systems on amd64 is a =
workaround.
Taken literally no paragraph explicitly covers powerpc/powerpc64 10.x =
contexts for how to bootstrap to have clang present in 11.0-CURRENT.
By content the one starting with "On 9.x" is the closest match for =
powerpc/powerpc64 10.x.
My variant text with []'s might better have been:
On 9.x installations where clang is enabled by default, e.g. on =
x86 and
powerpc [10.x too], 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++.
That would avoid odd implications for the combination x86 and 10.x by =
being explicitly localized to powerpc for the 10.x part.
But for powerpc (on-64) 10.1-STABLE even that adjustment would be =
wrong/incomplete...
powerpc 10.1-STABLE (3.4.1 clang present) does not build libcxxrt:
> ...
> building shared library libcxxrt.so.1
> /usr/bin/ld: warning: creating a DT_TEXTREL in a shared object.
> clang: error: linker command failed with exit code 1 (use -v to see =
invocation)
> *** Error code 1
That in turn means libc++'s build fails from the missing libcxxrt file =
that libc++'s build uses in its linking step.
That would make it rather hard to follow the instructions.
powerpc64 10.1-STABLE had no such problems building and installing those =
two libraries.
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
On 2015-Mar-12, at 10:01 AM, Mark Millard <markmi at dsl-only.net> =
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++.
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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