[LLVMdev] Problem with InsertPointGuard ABI? (original) (raw)

Paweł Bylica chfast at gmail.com
Tue Jul 21 09:36:23 PDT 2015

On Tue, Jul 21, 2015 at 6:30 PM Justin Bogner <mail at justinbogner.com> wrote:

Paweł Bylica <chfast at gmail.com> writes: > On Tue, Jul 21, 2015 at 5:55 PM Justin Bogner <mail at justinbogner.com> wrote: > > Paweł Bylica <chfast at gmail.com> writes: > > I can confirm that the issue has been caused by NDEBUG flag. > > > > On Mon, Jul 13, 2015 at 6:29 PM Reid Kleckner <rnk at google.com> wrote: > > > > The layout of AssertingVH has depended on NDEBUG since 2009, which > > predates any of our efforts to make LLVM's ABI resilient to > mismatched > > NDEBUG definitions between LLVM and its users. > > > > For now, make sure your definition of NDEBUG matches LLVM's. In the > long > > run, we could conceivably do something > > with LLVMENABLEABIBREAKINGCHECKS to allow this mismatch. > > > > In practice it is very hard to make NDEBUG flag match configs of your > project > > and LLVM project. You often need to build debug and release versions of > your > > project and LLVM is installed as a debian package or with homebrew. > Moreover, > > there is not reliable way of checking if LLVM has been built with or > without > > NDEBUG. > > FWIW, llvm-config --assertion-mode will tell you whether or not your > LLVM was built with or without NDEBUG. > > That's not true in all cases. In case CMAKEBUILDTYPE=Release, > LLVMENABLEASSERTIONS=Off and CMAKECXXFLAGSRELEASE="" llvm-config reports > asserts as off but NDEBUG flag is not set.

Um, okay, but why would you set CMAKECXXFLAGSRELEASE=""? That doesn't make any sense...

I agree, it make no sense. But homebrew actually does that: https://github.com/Homebrew/homebrew/blob/master/Library/Homebrew/formula.rb#L615

There are many possible solutions for this case:

  1. Force NDEBUG flag
  2. Report a cmake error.
  3. Get rid of LLVM_ENABLE_ASSERTIONS flag and relay on NDEBUG flag only.

> > > Can I do anything more about it? Contributions related to > > LLVMENABLEABIBREAKINGCHECKS needed? > > > > - Paweł > > _> > ________________________ > > LLVM Developers mailing list > > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150721/f9274e74/attachment.html>

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