Question about Gimple FE

[Jeff Law]

On 03/31/2015 09:34 AM, Trevor Saunders wrote:
> On Thu, Mar 26, 2015 at 03:15:22PM +0100, Richard Biener wrote:
>> On Thu, Mar 26, 2015 at 2:31 PM, xue yinsong <xyshh94225@hotmail.com> wrote:
>>> I think the gimple front end project would be quite useful to gcc so I’d like to do work on it this summer.
>>>
>>> The problem is, it seems the GIMPLE front end project hasn’t been active for some time
>>> and Diego Novillo told me it may not even make sense to use the same codebase, but start from scratch.
>>>
>>> I’m not sure if I should pick it up where it left off or write another one from scratch
>>>
>>> Could you give me some advice?
>>
>> I don't know the current codebase at all (unfortunately).  I think it
>> is useful to get yourself familiarized
>> with it even if you start from scratch as it will get you to learn
>> something about GIMPLE and about
>> writing a frontend.
>>
>> Note that LTO support already is able to output everything needed to
>> re-create GIMPLE thus from
>> there you can also learn what is required to populate a GIMPLE
>> representation.  And LTO support
>> might be used to create output that can be read by the GIMPLE frontend
>> - the whole project
>> feels like finding a textual form of the LTO bytecode (in some way).
>
> I think its part being able to convert LTO byte code to text, and part
> refactoring byte code reading / writing such that we can do things like
> read in byte code run a single pass and then dump the resulting byte
> code.  I suppose in a sense you can probably already do that with lto1
> and -r, but that's not exactly straight forward.
David has some code that allows creation of gimple on the fly and 
feeding it to a pass which is obviously designed with unit testing in mind.

Jeff