Re: Identifying source file locations.

[Neil Booth <neil at daikokuya dot demon dot co dot uk>]

Kenneth Almquist wrote:-

>  * The tree should contain file name information.  Otherwise, error
>    messages and debugging info can contain the wrong filename if
>    #line or #include directives are present.

Yup.  The filename should probably be a 16-bit index into a file
array.  And it should probably contain the column of the starting line
as well, for diagnostic purposes.

>  * It would be nice to have column information in most if not
>    all error messages.  We could retain column information
>    at least until we generate RTL.

Yes.

>  * The preprocessor complicates error reporting.  We might
>    associate two locations with each token that is the result of
>    preprocessor expansion:  the location of the preprocessor
>    name which was expanded, and the location of the token
>    in the #define directive.

Yes; I'm not sure what's best here.  Either both, or have it
specifiable on the command line to cut down on verbosity.  I know
people do want to be able to be pointed to the macro where a given
token came from.

> The Ada front end (GNAT) represents source locations as a 32 bit
> character position.

That would require a large table, with an entry per non-empty source
line.  I'm not sure that's any better than just using 48 bits for line
and column and keeping it simple.  Since C has include files and such,
a translation unit can get pretty enormous.

Neil.