[llvm-dev] [compiler-rt] '-fprofile-generate' and embedded systems

[Xinliang David Li via llvm-dev]

Right this is the way.  One feature that is missing for the buffer writer
is the value profiling support.

David

On Fri, May 26, 2017 at 9:07 AM, Simon Whittaker via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hi Martin,
>
> Can't you just port enough to get the existing:
>
> __llvm_profile_write_buffer
>
> functionality working? This shouldn't depend on IO. You then have free
> choice of how to get that buffer to somewhere persistent.
>
> This is something we use on PlayStation, in addition to the more usual
> "write a file" path.
>
> Thanks,
>
> Simon
>
>
> On 25 May 2017 7:07 a.m., "Martin J. O'Riordan via llvm-dev" <
> llvm-dev at lists.llvm.org> wrote:
>
> Yep, done that already, but it is not at all a good fit when the device is
> inside a drone flying around ;-)  What we do have, is a fake file-system
> that keeps everything in memory, and after the profiling is completed we
> offload it for analysis.  I guess I was hoping that there would be a more
> robust system agnostic implementation.  Use of ‘mmap’ is similarly
> constraining.
>
>
>
>             MartinO
>
>
>
> *From:* Nicholas Wilson [mailto:iamthewilsonator at hotmail.com]
> *Sent:* 25 May 2017 14:39
> *To:* Martin J. O'Riordan <martin.oriordan at movidius.com>
> *Cc:* LLVM Developers <llvm-dev at lists.llvm.org>
> *Subject:* Re: [llvm-dev] [compiler-rt] '-fprofile-generate' and embedded
> systems
>
>
>
> Well you could always write a ‘filesystem’ that shunts all data out the
> serial port (or similar).
>
>
>
> On 25 May 2017, at 9:12 pm, Martin J. O'Riordan via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>
>
> What is the best way of porting the ‘compiler-rt’ Profile library for an
> embedded system with no file-system (and hence no ‘fopen’, etc.)?
>
>
>
> What I would like to do is use it as normal, but then use a custom
> solution for getting the resulting data off the system.  It seems that this
> library (and the other compiler-rt libraries) are designed only to work
> with a hosted system.
>
>
>
> Are there any other embedded targets that this has been adapted for which
> would have similar constraints?
>
>
>
> Thanks,
>
>
>
>             MartinO
>
>
>
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