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Re: [EXTERNAL] Re: [Patch, F03, RFC] FINAL support in 4.8

Hi all,

Janus Weil wrote:
Finally, one runs into an ICE for conv_parent_component_references. That
happens in the finalization wrapper for the derived type "foo" where one
accesses "ptr%component%universal%counter", where the latter is part of an
abstract type. I haven't investigated why it fails.
... and I also end up with this.

I have a fix, but I do not understand the current code. In the finalization subroutine, "counter" of type "ref_counter" should be finalized. Hence, the generated code calls "__final_foo_implementation_Ref_counter" with the argument:


For some reason, that's incompatible with how gfc_conv_variable works. For "ptr%component" everything is fine. One then has as "ref" the component ref to "universal":

        case REF_COMPONENT:
          if (ref->u.c.sym->attr.extension)
            conv_parent_component_references (se, ref);
          gfc_conv_component_ref (se, ref);

As ref already is the "universal", the search for c->name "universal" in dt->components (with "dt = ref->u.c.sym") fails. Hence, a new ref ("parent") to "universal" is generated:
conv_parent_component_references (se, &parent);

However, after conv_parent_component_references returned, the next line again tries to add a ref to parent, which unsurprisingly fails.

I have no idea whether I did something different in the wrapper or whether it can also occur in general, however, it is fixed by the following patch.

* * *

Janus patch plus this one is sufficient to compile and run Damian's test, but it shows "fail". num_currently_allocated() returns 3 at the end - instead of 0. Comparing the result with the one I get with crayftn, I see missing lines of the type:

 finalize_ref_counter: start
 release: start
 release: end
 finalize_ref_counter: end

(Instead one has "finalize_ref_counter: start"/"finalize_ref_counter: end".)

Those seem to be due to the missing type-bound defined assignment, where Paul's patch is pending.

Additionally, "call_cpp_delte_foo" is never called. That one is called by release, which in turn seems to be require (cf. above) Paul's patch for PR46897. Hence, it is difficult to really see whether the code works correctly or not.


PS: I just saw that some of the calls to the wrapper are still incomplete. The finalization wrapper takes a "bool coarray" argument and while some calls pass "false" (or true) as second argument in the call to the wrapper, others don't.

The coarray argument is used - or will be used (I didn't look at the patch) - to decide whether to finalize the coarray component. For intrinsic assignment, it may not be reallocated (and hence finalized) while for DEALLOCATE of the parent or for going out of scope, it has to be finalized.

I am not completely sure whether one needs that flag, but presumably one does. (I only know for sure after fixing the COMPONENT issue, which we currently have deferred.)
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index b0bd7f5..4c7ff0a 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -1510,6 +1519,9 @@ conv_parent_component_references (gfc_se * se, gfc_ref * ref)
   dt = ref->u.c.sym;
   c = ref->u.c.component;
+  if (c->name == dt->name)
+    return;
   /* Return if the component is not in the parent type.  */
   for (cmp = dt->components; cmp; cmp = cmp->next)
     if (strcmp (c->name, cmp->name) == 0)

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