These are the Ada front-end bits.  They define the langhook to true and set 
the flags on individual ADDR_EXPR and CALL_EXPR nodes with Ada convention; in 
other words, descriptors are not activated for subprograms imported from or 
exported to other languages.


2016-07-04  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/misc.c (LANG_HOOKS_CUSTOM_FUNCTION_DESCRIPTORS): Def.
	* gcc-interface/trans.c (Attribute_to_gnu) <Attr_Access>: Deal with
	a zero TARGET_CUSTOM_FUNCTION_DESCRIPTORS specially for Code_Address.
	Otherwise, if TARGET_CUSTOM_FUNCTION_DESCRIPTORS is positive, set
	FUNC_ADDR_BY_DESCRIPTOR for 'Access/'Unrestricted_Access of nested
	subprograms if the type can use an internal representation.
	(call_to_gnu): Likewise, but set CALL_EXPR_BY_DESCRIPTOR on indirect
	calls if the type can use an internal representation.

-- 
Eric Botcazou