[PATCH] Adding a timing option for IR parsing

[Chandler Carruth]

On Fri, Mar 22, 2013 at 10:47 AM, Andrew Trick <atrick at apple.com> wrote:

>
> On Mar 22, 2013, at 9:14 AM, Eli Bendersky <eliben at google.com> wrote:
>
>
> On Thu, Mar 21, 2013 at 7:24 PM, Chandler Carruth <chandlerc at google.com>wrote:
>
>> FYI, I reverted the patch in r177695 to fix our builds. We check that
>> layering violations don't get any worse in our build system.
>>
>
> Can you explain what kind of build this breaks?
>
> I understand the layering problem, but how do we still get to measure the
> time IR parsing took? Do you have plans to fix the IR Reader violation any
> time soon?
>
>
> To answer your middle question. Just reuse -time-passes and expose the
> flag in LLVMContext.
>
> On the last question, I would like to see an answer to Chandler's question
> about whether anyone cares if they now automatically link the IR parser.
> Maybe Chandler should re-ask on llvm-dev?
>

Chatted with Chris on IRC and he seemed happier with a new library. I'm
adding that now.

It's called "IRReader" so we have IRReader/IRReader.h... if anyone really
wants a different name, shout...


> -Andy
>
> A temporary workaround would be to just add the measurement flag to
> llc.cpp - would anyone see a problem with that?
>
> Eli
>
>
>
>
>
>> Fundamentally, the existing layering problem is "worked around" but there
>> being no implementation. As long as thats true, all the Support library is
>> providing is a text header file. As long as it is only included into source
>> files that are part of a library which will eventually get linked with the
>> core library, the AsmParser library, and the BitcodeReader library, all is
>> well. Including it into a source file in Support makes the layering
>> violation actively worse.
>>
>> I think the correct solution is to do one of two things:
>>
>> 1) Create a new library which depends on both AsmParser and BitcodeReader
>> and which can be used by opt and friends. Put IRReader here.
>> 2) Fold AsmParser into the IR library (where AsmWriter already lives).
>> Put IRReader into the BitcodeReader library.
>>
>> I thought about a third option: put both AsmParser and IRReader into the
>> BitcodeReader library. But increasingly that seems like a really gross
>> layering.
>>
>> -Chandler
>>
>>
>> On Wed, Mar 20, 2013 at 9:59 PM, Chandler Carruth <chandlerc at google.com>wrote:
>>
>>>
>>> On Wed, Mar 20, 2013 at 8:23 PM, Andrew Trick <atrick at apple.com> wrote:
>>>
>>>> I don't pretend to understand the layering rules. But how can someone
>>>> use IRReader without linking LLVMCore? I'm not even sure why IRReader is in
>>>> Support given that it needs a context.
>>>
>>>
>>> IRReader is the layering violation. We should fix that, and then this
>>> becomes a non-problem.
>>>
>>> And yea, I think putting the flag in the context makes a lot of sense.
>>>
>>
>>
>
>
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