[llvm-dev] Need help with code generation

[Rui Ueyama via llvm-dev]

On Mon, Mar 21, 2016 at 8:33 PM, James Molloy <james at jamesmolloy.co.uk>
wrote:

> But you're surely not suggesting that lld will segfault as an error
> handling mode in production?
>

The document clearly states that (a) it is user's responsibility to give
sane object files, and (b) a corrupted file may cause a fatal error or SEGV.


> You say this was decided in a thread recently- could you please point me
> at that? I find this really hard to believe.
>

Please find it yourself, that was a long thread. The current decision was
not made lightly, so please respect that and take your time to understand
the situation.

Cheers,
>
> James
>
> On Mon, 21 Mar 2016 at 19:28, Rui Ueyama <ruiu at google.com> wrote:
>
>> On Mon, Mar 21, 2016 at 8:25 PM, James Molloy <james at jamesmolloy.co.uk>
>> wrote:
>>
>>> > Also, if it can segfault for some pathetic input
>>>
>>> Surely that's a bug though, not seriously designed behaviour?
>>>
>>
>> No. That is a design choice.
>>
>>
>>> On Mon, 21 Mar 2016 at 19:24 Rui Ueyama <ruiu at google.com> wrote:
>>>
>>>> We do not enable exceptions and longjmp is not safe. Also, if it can
>>>> segfault for some pathetic input, "it longjmps in most cases" doesn't help
>>>> people who wants 100% guarantee like you.
>>>>
>>>> On Mon, Mar 21, 2016 at 8:21 PM, James Molloy <james at jamesmolloy.co.uk>
>>>> wrote:
>>>>
>>>>> If it can exit, why can't it longjmp back to a library consumer at
>>>>> least?
>>>>>
>>>>> On Mon, 21 Mar 2016 at 19:20 Rui Ueyama <ruiu at google.com> wrote:
>>>>>
>>>>>> On Mon, Mar 21, 2016 at 8:16 PM, James Molloy <
>>>>>> james at jamesmolloy.co.uk> wrote:
>>>>>>
>>>>>>> > Correct
>>>>>>>
>>>>>>> Out of interest, how does LLD itself handle error reporting when
>>>>>>> invoked from the command line, and how does it avoid segfaulting in that
>>>>>>> case?
>>>>>>>
>>>>>>
>>>>>> It generally reports an error and exit, or in rare circumstances it
>>>>>> just segfaults.
>>>>>>
>>>>>>
>>>>>>> Cheers,
>>>>>>>
>>>>>>> James
>>>>>>>
>>>>>>> On Mon, 21 Mar 2016 at 19:14 Rafael Espíndola <
>>>>>>> rafael.espindola at gmail.com> wrote:
>>>>>>>
>>>>>>>> On 21 March 2016 at 15:10, James Molloy <james at jamesmolloy.co.uk>
>>>>>>>> wrote:
>>>>>>>> > Well sure, it's unlikely, but how many consumers can make that
>>>>>>>> sort of
>>>>>>>> > guarantee? And if a consumer can't guarantee the integrity of the
>>>>>>>> ELF file
>>>>>>>> > they have no choice but not to use LLD, or to fork before using
>>>>>>>> it.
>>>>>>>>
>>>>>>>> Correct.
>>>>>>>>
>>>>>>>> Cheers,
>>>>>>>> Rafael
>>>>>>>>
>>>>>>>
>>>>
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