Re: [gomp] parse OpenMP directives

[Paolo Bonzini <paolo dot bonzini at polimi dot it>]

> > Would it be fine to write a recursive descent parser used only for OpenMP
> > code, and then extend it to handle arbitrary translation units?
>
> Your one sentence description is too short to be a 
> properly assessable design (besides which some analysis of benefits and 
> requirements, and of what the minimal incremental components of the change 
> are, would be needed).

Add "incrementally" before write, and that will reflect my "design" (I 
was not trying to suggest a design).

> * Better error recovery and more accurate diagnostic location.

This is not going to happen at once.  See the C++ parser for examples.

> * Could the C++ parser be adapted?  (The principles of minimal incremental 
> changes mean that if the aim is to replace a parser then larger 
> replacements such as "merge C and C++ front ends" don't need considering 
> as alternatives, but a parser replacement could be considered as one 
> incremental change towards such a merge, depending on the design adopted.)

This way was estimated to be around 2-3 man years by Mark Mitchell, 
though it may be considered The Only Right Way To Do It.

Of course some parts of the C++ parser may be reused, for example the 
interface with cpplib or the binary expression parser.

> * Parser actions and code in c-parse.in can move to separate files 
> separately from a parser replacement, and so should move separately.  
> Otherwise replacing a parser with minimal changes to other files is the 
> minimal change.

Yes.  This may be merged in 4.1.

Paolo