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

On Sun, Jul 23, 2017 at 09:16:26PM -0400, Shawn Webb wrote:
> 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

Found the regression: It looks like lldb 5.0.0 doesn't support being
compiled with SafeStack. I'll report this upstream to llvm.

Thanks,

-- 
Shawn Webb
Cofounder and Security Engineer
HardenedBSD

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