[cfe-commits] [PATCH] Add -fcatch-undefined-behavior runtime library

[Michael Spencer]

On Thu, Oct 4, 2012 at 11:48 AM, Richard Smith <richard at metafoo.co.uk> wrote:
> On Thu, Oct 4, 2012 at 3:36 AM, Kostya Serebryany <kcc at google.com> wrote:
>>
>>
>> asan/tsan/msan generally avoid #including system headers, especially in .h
>> files.
>> Once you start porting the code to non-linux, you'll know why.
>> compiler-rt/lib/sanitizer_common contains lots of useful stuff that allows
>> you to avoid using system headers.
>> WDYT?
>
>
> I was trying to steer clear of most system headers, but I've tried a bit
> harder now; new patch attached.
>
> I'm not concerned about the includes in ubsan_diag.cc, since I intend for
> that code to be replaced in the medium term (and to be made user-replaceable
> -- some applications will want to provide their own reporting
> functionality). That only leaves <stdint.h> and <stddef.h>, which are both
> provided by Clang. I'm not hugely interested in making the runtime build
> with any other compiler, since you need to have a Clang which can target
> your platform anyway in order for it to be useful.
>
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This fails to compile with -Werror. ubsan_value.cc has 3 functions
with something similar to:

  SIntMax Value::getSIntValue() const {
    ...
    CHECK(0 && "unexpected bit width");
  }

Adding __builtin_unreachable(); fixes this. Does compiler-rt have a
compatibility macro for this?

- Michael Spencer