Refactor compute_objsize_r into helpers.

Refactor compute_objsize_r into helpers.

gcc/ChangeLog:

	* pointer-query.cc (compute_objsize_r): Add an argument.
	(gimple_call_return_array): Pass a new argument to compute_objsize_r.
	(access_ref::merge_ref): Same.
	(access_ref::inform_access): Add an argument and use it.
	(access_data::access_data): Initialize new member.
	(handle_min_max_size): Pass a new argument to compute_objsize_r.
	(handle_decl): New function.
	(handle_array_ref): Pass a new argument to compute_objsize_r.
	Avoid incrementing deref.
	(set_component_ref_size): New function.
	(handle_component_ref): New function.
	(handle_mem_ref): Pass a new argument to compute_objsize_r.
	Only increment deref after successfully computing object size.
	(handle_ssa_name): New function.
	(compute_objsize_r): Move code into helpers and call them.
	(compute_objsize): Pass a new argument to compute_objsize_r.
	* pointer-query.h (access_ref::inform_access): Add an argument.
	(access_data::ostype): New member.