[cfe-dev] Target specific semantic checking.

[Sanjiv Gupta]

I wanted to issue an error (for pic16) when a function marked as ISR has 
any params.
Refer 79596.

Due to absence of an "interrupt" function attribute, pic16 uses section 
attribute to encode this information.
Otherwise, it is a pretty generic functionality valid for every target 
and can be implemented in a generic way.

I am looking for ideas on how to solve this:
A. by adding an "interrupt" attribute ?
OR
B. by having a hook in TargetInfo ? This is a little out of the way as 
the hook will need to access Function Attrs.
OR
C. Any other ideas?

- Sanjiv