firebox build fails post clang-3.4 merge

[Benjamin Kaduk]

On Wed, 26 Feb 2014, Don Lewis wrote:

> On 26 Feb, Michael Butler wrote:
>> On 02/18/14 12:10, Michael Butler wrote:
>>> Is anyone else seeing firefox failing to install after the clang-3.4
>>> merge? As in xpcshell dumping core ..
>>
>> An update ..
>>
>> Recompiling with GCC48 on -current yields the same result. Seems to run
>> correctly when invoked from the command-line but seg-faults with "errno
>> = 4" (invalid instruction) from the build
>>
>> Giving up and using the Linux port .. :-(
>
> I've also seen this problem with clang-3.4 on i386.  It looks like a
> clang bug to me.  Clang is putting ud2 instructions in its output which
> are guaranteed to fault when it compiles nsAppRunner.cpp.  See
> <http://www.freebsd.org/cgi/query-pr.cgi?pr=187103>.

That would seem to indicate that clang believes the source code in 
question is exercising a case which is explicitly listed as giving 
undefined behavior in the language specification. Presumably that means we 
need a C++ language lawyer to look over the code in question.

-Ben Kaduk