[cfe-dev] Clang produces corrupt pch leading to crash

[Nikola Smiljanic]

It might make sense to file this with apple if you're using clang shipped
with XCode as they ship their own releases. What version of clang are you
using? Is the isystem flag important? What about #include <list>? I've
tried to reproduce this but it's not so straightforward because I'm on
linux and some of the stuff in that bash script assumes mac os... I was
wondering if it's possible to reduce this to something that's reproducible
everywhere or if this is a mac specific issue.


On Mon, Jun 16, 2014 at 11:55 PM, Nikola Smiljanic <popizdeh at gmail.com>
wrote:

> Thanks for the detailed report! The only thing you can do more is try and
> debug this yourself ;)
>
>
> On Mon, Jun 16, 2014 at 8:33 PM, Tobias Hahn <tobias.hahn at ableton.com>
> wrote:
>
>> Hi all,
>>
>> I've run into (what I believe is) a memory bug with clang while producing
>> a precompiled header. In short, under certain circumstances, clang will
>> write a pch that causes a crash when trying to use this pch in a later
>> compilation unit.
>>
>> Occasionally, while clang is compiling the pch, malloc complains that one
>> of its checksums has been overwritten; while at other times, clang throws
>> an error that a definition has a different exception specification than the
>> declaration two lines above it (when both have no exception specification).
>> Both these symptoms lead me to believe that somewhere clang overwrites
>> memory.
>>
>> I have stripped the code that reliably causes this crash down to a few
>> hundred lines and have created a little script to reproduce the bug
>> (details at http://llvm.org/bugs/show_bug.cgi?id=20026). I'm not sure,
>> however, about your process for handling such bugs, which is why I'm
>> cross-posting here. My main question is if there is anything else I could
>> provide you with to help fixing this issue.
>>
>> Thank you very much in advance!
>>
>> Best,
>> Tobias
>>
>>
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>>
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