[PLUGIN] Fix PLUGIN_FINISH_TYPE

[Romain Geissler]

Hi

2011/9/12 Dodji Seketeli <dodji@seketeli.org>:
 > Romain Geissler <romain.geissler@gmail.com> a écrit:
 >> When i recontributed the PLUGIN_FINISH_DECL patch from the original
 >> Brian Hackett, i didn't exactly checked  what may or may not trigger
 >> this new event. I know for example that declaring a function triggers
 >> this event, but defining it does not.
 >>
 >> I don't really know when those event should be triggered, we should
 >> clarify the meaning of those.
 >>
 >> According to me:
 >> PLUGIN_FINISH_DECL should be triggered anytime the parser parse a
 >> declaration (which includes declaration + definition of function,
 >> typedef definition, namespaces, ..., all DECL_P trees built by the
 >> parser).
 >
 > The general idea sounds sensible, IMHO.  However, we must keep in mind
 > that there are cases like, e.g, 'struct C;' where G++ creates a typedef
 > 'typedef struct C C;' so that you can name that type 'C' instead of
 > having to type "struct C' all the time.  For these cases, I don't think
 > the PLUGIN_FINISH_DECL event should be emitted.

I agree.

 >
 >> For, PLUGIN_FINISH_TYPE i don't really know it means a new type
 >> declaration (or declaration + definition) or if it means usage of a
 >> type (in a function prototype, the type of a local variable.
 >
 > I'd say it's a definition of a new type, IMHO.

Ok, so it only involves struct, unions, enum and class declaration / definitions.

 >
 >> I would rather vote for new type definition (including typedefs)
 >
 > My understanding is that a typedef declaration doesn't define a new
 > type.  Rather, it declares an alias for an existing type.  As such, I
 > would think that notifying typedef declarations via PLUGIN_FINISH_DECL
 > would be the way to go.

Ok

 >
 >> but for special cases of struct, you can declare and use them at the
 >> same time:
 >
 > Just to be sure I understand, do you need to be notified about *uses* of
 > types and decls as well?  If so, maybe a new kind of event should
 > probably be defined, because PLUGIN_FINISH_DECL and PLUGIN_FINISH_TYPE
 > seem to have more to do with declaring/defining decls and types than
 > using them.
 >

Personally i don't need to catch all struct uses, but i need to catch struct declarations.
I want to apply some __attributes__ to a given struct type, for example let's say i need 
to mark *struct my_struct* as deprecated thanks to a plugin. I know how to apply some 
attributes to a type or a decl. See the plugin (test_plugin.c) and the test files attached.

With test_pass.c, my_struct is declared first, then defined after, applying the deprecated 
attribute works.
With test_fail.c, my_struct is declared and defined at the same time, applying the 
deprecated attribute doesn't work with the current trunk (and also with my patch).
I got:
test_fail.c:4:1: warning: type attributes ignored after type is already defined [-Wattributes]

So i may need a PLUGIN_FINISH_TYPE_DECLARATION triggered when the type is declared but 
before it is finally defined.

Does two different events PLUGIN_FINISH_TYPE_DECLARATION and PLUGIN_FINISH_TYPE_DEFINITION 
make sens to you ?

 > --
 >                Dodji
 >

Romain Geissler
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