The `@visibility' attribute is functionality the same as
`__attribute__((visibility))', and `@hidden' is a convenience alias to
`@visibility("hidden")' defined in the `gcc.attributes' module.
As the visibility of a symbol is also indirectly controlled by the
`export' keyword, the handling of this in the code generation pass has
been improved so that conflicts will be appropriately diagnosed.
gcc/d/ChangeLog:
* d-attribs.cc (d_langhook_attribute_table): Add visibility.
(insert_type_attribute): Use decl_attributes instead of
merge_attributes.
(insert_decl_attribute): Likewise.
(apply_user_attributes): Do nothing when no UDAs applied.
(d_handle_visibility_attribute): New function.
* d-gimplify.cc (d_gimplify_binary_expr): Adjust.
* d-tree.h (set_visibility_for_decl): Declare.
* decl.cc (get_symbol_decl): Move setting of visibility flags to...
(set_visibility_for_decl): ... here. New function.
* types.cc (TypeVisitor::visit (TypeStruct *)): Call
set_visibility_for_decl().
(TypeVisitor::visit (TypeClass *)): Likewise.
gcc/testsuite/ChangeLog:
* gdc.dg/attr_visibility1.d: New test.
* gdc.dg/attr_visibility2.d: New test.
* gdc.dg/attr_visibility3.d: New test.