Re: PATCH: flag_external and DECL_EXTERNAL documentation

[Lars Brinkhoff <lars dot spam at nocrew dot org>]

Jason Merrill <jason@redhat.com> writes:
> > -/* In a VAR_DECL or FUNCTION_DECL,
> > -   nonzero means external reference:
> > -   do not allocate storage, and refer to a definition elsewhere.  */
> > +/* In a VAR_DECL or FUNCTION_DECL, nonzero means external reference:
> > +   do not allocate storage, and refer to a definition elsewhere.
> > +   Note that DECL_EXTERNAL is always set when a non-nested function is
> > +   declared, and cleared when the function definition is encountered. */
> 
> This is describing C-specific behavior, and should not be in a backend
> file.  In C, function declarations are implicitly extern, but this may not
> be true of other languages.
> 
> I think the existing comment is fine.

In the back end I'm currently writing, whenever a function call is to
be generated I need to know whether the function is defined in the
current translation unit or not.  After reading the comment, I thought
DECL_EXTERNAL provided that information.

Since DECL_EXTERNAL doesn't quite work for this, is there another way
to find out whether a function is defined in the current translation
unit?  I'm assuming that the user may have to explicitly declare this
(i.e. declaring a function to be "extern", or not, in C).

-- 
http://lars.nocrew.org/