Bug 216614

Summary:

editors/emacs-devel: clang 4.0 crashes during build

Product:

Ports & Packages

Reporter:

Jan Beich <jbeich>

Component:

Individual Port(s)

Assignee:

Ashish SHUKLA <ashish>

Status:

Closed FIXED

Severity:

Affects Only Me

CC:

dim

Priority:

---

Keywords:

needs-patch

Version:

Latest

Flags:

bugzilla: maintainer-feedback? (ashish)

Hardware:

Any

OS:

Any

See Also:

https://llvm.org/bugs/show_bug.cgi?id=31809

Bug Depends on:

Bug Blocks:

216008

Attachments:

Description	Flags
src/buffer.c (preprocessed, compressed)	none
command line args (for clang 4.0)	none

Description Jan Beich freebsd_committer

2017-01-30 21:45:12 UTC

Assertion failed: ((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"), function computeKnownBits, file /usr/src/contrib/llvm/lib/Analysis/ValueTracking.cpp, line 1594.
cc: error: unable to execute command: Abort trap
cc: error: clang frontend command failed due to signal (use -v to see invocation)
FreeBSD clang version 4.0.0 (branches/release_40 293443) (based on LLVM 4.0.0)
Target: x86_64-unknown-freebsd12.0
Thread model: posix
InstalledDir: /usr/bin

http://package18.nyi.freebsd.org/data/headamd64PR216008-default/2017-01-29_16h09m05s/logs/errors/emacs-devel-26.0.50.20170121,2.log

Comment 1 Jan Beich freebsd_committer

2017-01-30 21:47:19 UTC

Created attachment 179444 [details]
src/buffer.c (preprocessed, compressed)

Comment 2 Jan Beich freebsd_committer

2017-01-30 21:47:52 UTC

Created attachment 179445 [details]
command line args (for clang 4.0)

Comment 3 Dimitry Andric freebsd_committer

2017-01-31 07:53:58 UTC

Reproduced, test case submitted in upstream bug:
https://llvm.org/bugs/show_bug.cgi?id=31809

Comment 4 commit-hook freebsd_committer

2017-02-02 23:02:29 UTC

A commit references this bug:

Author: dim
Date: Thu Feb  2 23:01:30 UTC 2017
New revision: 313110
URL: https://svnweb.freebsd.org/changeset/base/313110

Log:
  Pull in r293773 from upstream llvm trunk (by Sanjay Patel):

    [ValueTracking] avoid crashing from bad assumptions (PR31809)

    A program may contain llvm.assume info that disagrees with other
    analysis. This may be caused by UB in the program, so we must not
    crash because of that.

    As noted in the code comments:
    https://llvm.org/bugs/show_bug.cgi?id=31809
    ...we can do better, but this at least avoids the assert/crash in the
    bug report.

    Differential Revision: https://reviews.llvm.org/D29395

  This fixes an assertion when building editors/emacs-devel.

  PR:		216614

Changes:
  projects/clang400-import/contrib/llvm/lib/Analysis/ValueTracking.cpp

Comment 5 Dimitry Andric freebsd_committer

2017-02-02 23:05:48 UTC

Should be fixed now.  Note that upstream has indicated that what emacs is doing is most likely some undefined behavior, so please take care.  I have built emacs-devel with this fix, and it seems to work OK, with light testing (both in a terminal, and as an X client).