Question about Gimple FE

[Jeff Law]

On 04/03/2015 07:45 AM, Diego Novillo wrote:
>
>
> On 04/02/15 11:59, xue yinsong wrote:
>> I suppose our goal is to translate the dumped program back to
>> the C source code (otherwise we can simply retain the gotos and
>> labels since they are already `valid’ in C). In this case we have to
>> convert the gotos back to if-elses and whiles. As long as
>> CFG informations are given, it’s possible to get rid of these gotos.
>
> Not quite. The output of the debug dumpers is not really meant to be fed
> back to the compiler. They are debug dumps only. They do not contain
> enough information for code generation or analysis.
But that's something that could be fixed.

I think the fundamental question is whether or not to start with the 
debug dumps or from scratch with a new format.  Either way we want a 
format that is easily readable back into the compiler, but also easily 
modifable by a human or a preprocessor for test generation.


What's also interesting here is David's work which is a step towards 
allowing a program to generate gimple and inject it into the compiler at 
interesting points.  So we could have a generator program which 
generates gimple, feeds it into a pass, then verifies the result.  What 
I'm struggling with here is balancing the human cost of building a test 
in David's kind of framework vs doing something easier in a gimple-FE 
like framework vs what we do now where it's bloody hard to arrange for 
bits to get to a specific pass in a specific state.

jeff