exp_ch5.adb (Expand_N_Assignment_Statement): For the assignment of a controlled type...

2007-04-20  Ed Schonberg  <schonberg@adacore.com>
	    Gary Dismukes  <dismukes@adacore.com>
	    Javier Miranda  <miranda@adacore.com>

	* exp_ch5.adb (Expand_N_Assignment_Statement): For the assignment of a
	controlled type, use Make_Handler_For_Ctrl_Operation to construct the
	required exception handler.
	(Expand_Simple_Function_Return, Expand_N_Return_Statement): Handle
	properly the case of a function whose return type is a limited
	class-wide interface type. Modify the code of the accessibility
	check to handle class-wide interface objects. In this case we need to
	displace "this" to reference the primary dispatch table to get access
	to the TSD of the object (to evaluate its accessibility level).
	(Expand_N_Extended_Return_Statement): Test for a tagged result type
	rather than a controlling result as one of the conditions for
	generating tests of the implicit BIP_Alloc_Form formal. The
	initialization assignment is also handled according to whether the
	result is tagged instead of controlling.
	In the case where the init assignment is inserted in the "then" part of
	the allocation conditional, rewrite the target to be a dereference of
	the implicit BIP_Object_Access formal.
	If the returned value is unconstrained and created on the secondary
	stack, mark the enclosing block and function so that the secondary
	stack is not reclaimed on return.
	Treat returns from functions with controlling results similarly to
	returns from functions with unconstrained result subtypes.
	If the object returned is unconstrained, and an allocator must be
	created for it, analyze the allocator once the block for the extended
	return is installed, to ensure that finalizable components
	of the expression use the proper finalization list. Guard the call to
	Move_Final_List with a check that there is something to finalize.
	(Make_Tag_Ctrl_Assignment): Use "old" handling
	of controlled type assignment for virtual machines, since new code uses
	unsupported features (such as direct access to bytes in memory).

From-SVN: r125398