Re: qual_union_type help
> This makes sense this we can't gimplify a placeholder expression. So > this seems that when i make a constructor for the QUAL_UNION_TYPE i > must iterate the fields and replace the placeholder_expr to have a > reference to the discriminant via another COMPONENT_REF. Though does > this mean for the constructor i will need to create a temporary to > hold onto it to create another component_ref? The Ada compiler gets rid of all PLACEHOLDER_EXPRs in CONSTRUCTORs because the subtype of these CONSTRUCTORs is always constrained in Ada parlance, i.e. you know the value of the discriminant since it is assigned in the CONSTRUCTOR, so the gimplifier is indeed presumably not wired to eliminate them on its own. -- Eric Botcazou -- Gcc-rust mailing list Gcc-rust@gcc.gnu.org https://gcc.gnu.org/mailman/listinfo/gcc-rust
Re: qual_union_type help
> That makes sense during construction we also know what the value of > the discriminant is. What does the Ada front-end replace the > placeholder_exprs with? Can it simply be the value of the discriminant > at constructor? I haven't tried that. Ultimately all PLACEHOLDER_EXPRs need to be replaced by something in the code, i.e. they can only survive in (abstract) types. There is an entire machinery in tree.c for that, called both from the front-end and middle-end in Ada. You can replace it with an explicit value (SUBSTITUTE_IN_EXPR) or you can search for it in an object (SUBSTITUTE_PLACEHOLDER_IN_EXPR). You can presumably do it through the gimplification hook. -- Eric Botcazou -- Gcc-rust mailing list Gcc-rust@gcc.gnu.org https://gcc.gnu.org/mailman/listinfo/gcc-rust
