PR debug/7081: emit DW_TAG_class_type and DW_TAG_interface_type

[Jakub Jelinek]

On Wed, Dec 05, 2007 at 07:41:34AM -0800, Ian Lance Taylor wrote:
> Alexandre Oliva <aoliva@redhat.com> writes:
> 
> > We've long output C++ classes and Java classes and interfaces as
> > DW_TAG_structure_type.  This patch fixes it, with a different approach
> > from the one proposed at
> > http://gcc.gnu.org/ml/gcc-patches/2003-06/msg01748.html
> > 
> > Instead of moving the declared-as-class bit from C++ into common
> > trees, it introduces a langhook to let the language decide what is a
> > class, what is an interface and what is a structure.
> 
> Offhand, I don't see how that could work with LTO.  Since we need to
> add new functionality regardless, I'd rather see something which we
> can support in LTO.

Why can't this work with LTO?  The type's full debug info will be in
the emitted debug info, so the LTO frontend can just add its own
language bits when parsing something special (e.g. DW_TAG_class_type,
DW_TAG_interface_type in this case, or special info about Fortran
deferred/assumed-{shape,size} etc. arrays, or whether DW_TAG_member
(vs. DW_TAG_variable) was used, etc.), stick them in LTO's struct lang_type
resp. struct lang_decl and then give back to the debugger using the
langhook.
That way this bloats only LTO compilations, languages which never need
these don't need to waste bits in decls or types and languages which
need it have it there already.

	Jakub