Re: HEADS-UP: Merged llvm/clang 5.0.0 into -CURRENT (as of r321369)

On Sun, Jul 23, 2017 at 07:34:47PM -0400, Shawn Webb wrote:
> On Sun, Jul 23, 2017 at 04:13:18PM -0700, Mark Millard wrote:
> > Shawn Webb shawn.webb at hardenedbsd.org wrote on
> > Sat Jul 22 15:33:14 UTC 2017 :
> > 
> > > I haven't nailed down whether it's SafeStack, CFI, or using lld as the
> > > default linker, but it looks like we in HardenedBSD are getting an
> > > undefined symbol during buildworld.
> > 
> > In an amd64 -> TARGET_ARCH=powerpc64 cross build context 
> > for FreeBSD -r321371 I got a similar report for the:
> > 
> > /usr/obj/usr/src/tmp/usr/bin/ld: error: undefined symbol: lldb_private::AppleObjCRuntime::GetFoundationVersion()
> > >>> referenced by /usr/src/contrib/llvm/tools/lldb/source/Plugins/Language/ObjC/Cocoa.cpp
> > >>>               Cocoa.o:(lldb_private::formatters::NSNumberSummaryProvider(lldb_private::ValueObject&, lldb_private::Stream&, lldb_private::TypeSummaryOptions const&)) in archive /usr/obj/usr/src/lib/clang/liblldb/liblldb.a
> > 
> > part of your report (logfile). The context used
> > devel/powerpc64-binutils :
> > 
> > # /usr/local/powerpc64-freebsd/bin/ld --version
> > GNU ld (GNU Binutils) 2.28
> > Copyright (C) 2017 Free Software Foundation, Inc.
> > This program is free software; you may redistribute it under the terms of
> > the GNU General Public License version 3 or (at your option) a later version.
> > This program has absolutely no warranty.
> > 
> > (lld is not yet  working option for powerpc64 as
> > far as I know.)
> > 
> > For this part of your report I doubt that anything
> > that you listed is required for the problem to happen.
> > 
> > In my context the error text was:
> > 
> > --- lldb.full ---
> > /usr/obj/powerpc64vtsc_clang_altbinutils/powerpc.powerpc64/usr/src/lib/clang/liblldb/liblldb.a(Cocoa.o): In function `lldb_private::formatters::NSNumberSummaryProvider(lldb_private::ValueObject&, lldb_private::Stream&, lldb_private::TypeSummaryOptions const&)':
> > /usr/src/contrib/llvm/tools/lldb/source/Plugins/Language/ObjC/Cocoa.cpp:(.text._ZN12lldb_private10formatters23NSNumberSummaryProviderERNS_11ValueObjectERNS_6StreamERKNS_18TypeSummaryOptionsE+0x398): undefined reference to `lldb_private::AppleObjCRuntime::GetFoundationVersion()'
> 
> Hey Mark,
> 
> I wasn't doing a cross-build, but rather a native build for amd64. I'm
> getting errors again. In fact, I'm getting the same error you just
> posted above. I have no clue why the error's happening. That you're
> also getting the error shows that the issue isn't specific to
> HardenedBSD at the very least.

I've figured out how to fully reproduce. The following assumes world
still is at clang/llvm 4.0. The following also assumes the source tree
is at /usr/src and is latest FreeBSD HEAD. And MAKEOBJDIRPREFIX is unset
or left as default. Native build on amd64.

1. Set ld.lld as the linker:
   a. rm /usr/bin/ld
   b. ln -s ld.lld /usr/bin/ld
   c. Verify: `ld -version` should show:
      LLD 4.0.0 (FreeBSD 297347) (compatible with GNU linkers)
2. Ensure the object tree is clean:
   a. rm -rf /usr/obj/usr/src
3. Build world:
   a. make -sj$(sysctl -n hw.ncpu) buildworld
4. Relax, grab a drink, eat some Skittles
5. Come back to buildworld failing to link lldb.full in
   usr.bin/clang/lldb

Thanks,

-- 
Shawn Webb
Cofounder and Security Engineer
HardenedBSD

GPG Key ID:          0x6A84658F52456EEE
GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89  3D9E 6A84 658F 5245 6EEE