[Bug target/66523] New: the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[Bug target/66523] New: the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

            Bug ID: 66523
           Summary: the new clang-based assembler in Xcode 7 on 10.11
                    fails on libobjc/NXConstStr.m
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: howarth.at.gcc at gmail dot com
  Target Milestone: ---

Created attachment 35773
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35773&action=edit
proposed fix from Iain Sandoe

The new clang-based assembler in Xcode 7 fails to build libobjc in FSF gcc 5.1
with the following error...

/bin/sh ./libtool  --mode=compile
/sw/src/fink.build/gcc5-5.1.0-2/darwin_objdir/./gcc/xgcc
-B/sw/src/fink.build/gcc5-5.1.0-2/darwin_objdir/./gcc/
-B/sw/lib/gcc5/x86_64-apple-darwin15.0.0/bin/
-B/sw/lib/gcc5/x86_64-apple-darwin15.0.0/lib/ -isystem
/sw/lib/gcc5/x86_64-apple-darwin15.0.0/include -isystem
/sw/lib/gcc5/x86_64-apple-darwin15.0.0/sys-include   
/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/NXConstStr.m -c \
           -I. -I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc   -g -O2 -W
-Wall -Wwrite-strings -Wstrict-prototypes -DIN_GCC -DIN_TARGET_LIBS
-fno-strict-aliasing -fexceptions
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../gcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../gcc/config -I../.././gcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../libgcc -I../libgcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../include  -fgnu-runtime \
           -o NXConstStr.lo
libtool: compile:  /sw/src/fink.build/gcc5-5.1.0-2/darwin_objdir/./gcc/xgcc
-B/sw/src/fink.build/gcc5-5.1.0-2/darwin_objdir/./gcc/
-B/sw/lib/gcc5/x86_64-apple-darwin15.0.0/bin/
-B/sw/lib/gcc5/x86_64-apple-darwin15.0.0/lib/ -isystem
/sw/lib/gcc5/x86_64-apple-darwin15.0.0/include -isystem
/sw/lib/gcc5/x86_64-apple-darwin15.0.0/sys-include
/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/NXConstStr.m -c -I.
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc -g -O2 -W -Wall
-Wwrite-strings -Wstrict-prototypes -DIN_GCC -DIN_TARGET_LIBS
-fno-strict-aliasing -fexceptions
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../gcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../gcc/config -I../.././gcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../libgcc -I../libgcc
-I/sw/src/fink.build/gcc5-5.1.0-2/gcc-5.1.0/libobjc/../include -fgnu-runtime 
-fno-common -DPIC -o .libs/NXConstStr.o
/var/tmp//ccc9efWx.s:98:17: error: non-local symbol required in directive
        .no_dead_strip L_OBJC_Module
                       ^
make: *** [NXConstStr.lo] Error 1

The proposed patch from Iain Sandoe suppresses this assembler error and allows
libobjc to build under the clang-based assembler.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #1 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
Previously filed as radr://21323034, "the new clang-based assembler in Xcode 7
on 10.11 fails on the NXConstStr.s file from FSF gcc 5.1"

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[kassafari at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

kassafari at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kassafari at gmail dot com

--- Comment #2 from kassafari at gmail dot com ---
status check

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #3 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to kassafari from comment #2)
> status check

you can use the patch in the short-term, but I want to check for other
solutions too.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #4 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
FYI, Apple's response on radar was...

This is correct behavior from the assembler. The GNU objc runtime is doing bad
things here by assuming an assembler local symbol (any symbol starting with
“L”) is not, in fact, assembler local and will instead live on for the linker
to see. We advise you don’t do that.
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Subject: [Bug c++/65882] [5/6 Regression] Internal compiler error: Error reporting routines re-entered
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide882

--- Comment #6 from Mikhail Maltsev <miyuki at gcc dot gnu.org> ---
Author: miyuki
Date: Sat Jun 20 00:10:00 2015
New Revision: 224702

URL: https://gcc.gnu.org/viewcvs?rev"4702&root=gcc&view=rev
Log:
PR c++/65882

gcc/cp/
        * call.c (build_new_op_1): Check tf_warning flag in all cases.

gcc/testsuite/
        * g++.dg/diagnostic/inhibit-warn-1.C: New test.
        * g++.dg/diagnostic/inhibit-warn-2.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/diagnostic/inhibit-warn-1.C
    trunk/gcc/testsuite/g++.dg/diagnostic/inhibit-warn-2.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/testsuite/ChangeLog

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #5 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
This is the last remaining issue with building gcc trunk using the clang-based
assembler in Xcode 7. Should we check in Iain's proposed fix for now as a
stop-gap fix>

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mrs at gcc dot gnu.org

--- Comment #6 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Another proposal, any symbol with an 'L.*' spelling should be not so marked, as
these can never be used this way.  Seems like we should have a predicate to
call before marking something as no dead strip and it should get rid of all of
them, including L.* symbols.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #7 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to mrs@gcc.gnu.org from comment #6)
> Another proposal, any symbol with an 'L.*' spelling should be not so marked,
> as these can never be used this way.  Seems like we should have a predicate
> to call before marking something as no dead strip and it should get rid of
> all of them, including L.* symbols.

that's pretty much what my comment says - however, what I want to check (when I
get a spare ns) is whether ObjC should be emitting "l_xxx" symbols for these
(i.e. linker-only-visible, but not preserved).  If someone else has time to
look before me, then fine :)

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-07-07
     Ever confirmed|0                           |1

--- Comment #8 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Iain Sandoe from comment #7)
> (In reply to mrs@gcc.gnu.org from comment #6)
> > Another proposal, any symbol with an 'L.*' spelling should be not so marked,
> > as these can never be used this way.  Seems like we should have a predicate
> > to call before marking something as no dead strip and it should get rid of
> > all of them, including L.* symbols.
> 
> that's pretty much what my comment says - however, what I want to check
> (when I get a spare ns) is whether ObjC should be emitting "l_xxx" symbols
> for these (i.e. linker-only-visible, but not preserved).  If someone else
> has time to look before me, then fine :)

So, I had a look at what Apple gcc-4.2.1 and current TOT clang produce.
gcc-4.2.1 is silent about preservation.
clang puts the relevant stuff into sections marked as "no_dead_strip" (but
doesn't mark the individual symbols).

For LTO to work we need to mark these items as non-strippable, because that
happens in a way that won't see that the containing section is "no_dead_strip".

Thus, for now, I think that the patch I have in my Q is OK.

(as a follow-on, I think to revise the section headers to ensure that they
contain "no_dead_strip", but that needs to be checked to be compatible with the
range of ld64 variants we use).

The current patch does what Mike has suggested above - rejects symbols starting
with L* as no_dead_strip.

Any other opinions (or shall I post/apply the patch)?

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #9 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Ok.  Ok for all active release branches.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #10 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
I assume we have missed the window for gcc 5.2.0.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #11 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
No, but one has to get RM approval.  Should be easy enough to get that, as long
as the work gets done before they make the last snapshot.

Does someone have the regression test done on the release branch (and trunk)? 
Does it look good on both?  If so, I can ask them RM if I can drop it in.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #12 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
Regression testing of gcc-5.2.0-RC-20150707 with
https://gcc.gnu.org/bugzilla/attachment.cgi?id=35773 applied posted at...

https://gcc.gnu.org/ml/gcc-testresults/2015-07/msg00825.html

showing no regressions compared to the previous results for gcc 5.1.1 without
the proposed fix applied...

https://gcc.gnu.org/ml/gcc-testresults/2015-07/msg00300.html

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #13 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Author: mrs
Date: Wed Jul  8 16:56:46 2015
New Revision: 225565

URL: https://gcc.gnu.org/viewcvs?rev=225565&root=gcc&view=rev
Log:
2015-07-08  Iain Sandoe  <iain@codesourcery.com>

        PR target/66523
        * config/darwin.c (darwin_mark_decl_preserved): Exclude 'L' label names
from
        preservation.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/darwin.c

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
      Known to work|                            |6.0
   Target Milestone|---                         |5.2
           Severity|normal                      |major

--- Comment #14 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Fixed in trunk, awaiting RM approval for gcc 5.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #15 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Jack, can you spin a gcc-4.9 test?

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #16 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
Regression testing of gcc trunk with fix posted at
https://gcc.gnu.org/ml/gcc-testresults/2015-07/msg00873.html

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #17 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
Any response on the request for RM approval for adding this to 5.2.0?

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #18 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Author: mrs
Date: Thu Jul  9 17:50:58 2015
New Revision: 225623

URL: https://gcc.gnu.org/viewcvs?rev=225623&root=gcc&view=rev
Log:
2015-07-09  Iain Sandoe  <iain@codesourcery.com>

        PR target/66523
        * config/darwin.c (darwin_mark_decl_preserved): Exclude 'L' label names
from
        preservation.

Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/config/darwin.c

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #19 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Author: mrs
Date: Thu Jul  9 17:56:23 2015
New Revision: 225624

URL: https://gcc.gnu.org/viewcvs?rev=225624&root=gcc&view=rev
Log:
2015-07-09  Iain Sandoe  <iain@codesourcery.com>

        PR target/66523
        * config/darwin.c (darwin_mark_decl_preserved): Exclude 'L' label names
from
        preservation.

Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/config/darwin.c

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[mrs at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to work|                            |4.9.4, 5.1.1, 5.2.0
         Resolution|---                         |FIXED
      Known to fail|                            |4.9.3, 5.1.0

--- Comment #20 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> ---
Fixed.

[Bug target/66523] the new clang-based assembler in Xcode 7 on 10.11 fails on libobjc/NXConstStr.m

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66523

--- Comment #21 from Jack Howarth <howarth.at.gcc at gmail dot com> ---
(In reply to mrs@gcc.gnu.org from comment #15)
> Jack, can you spin a gcc-4.9 test?

Regression test results for current gcc-4_9-branch with patch applied posted at
https://gcc.gnu.org/ml/gcc-testresults/2015-07/msg00953.html