Fortran: Fix bugs and missing features in finalization [PR37336]

Fortran: Fix bugs and missing features in finalization [PR37336]

2023-03-18  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/103854
	PR fortran/96122
	PR fortran/37336
	* class.cc (finalize_component): Include the missing arguments
	in the call to the component's finalizer wrapper.
	(has_finalizer_component): Do not return true for procedure
	pointer components.
	(finalizer_insert_packed_call): Remove the redundant argument
	in the call to the final subroutine.
	(generate_finalization_wrapper): Add support for assumed rank
	finalizers.
	(gfc_may_be_finalized): New helper function.
	* dump-parse-tree.cc (write_proc): Whitespace.
	* gfortran.h : Add prototype for gfc_may_be_finalized.
	* resolve.cc (resolve_function): Correct derived types that
	have an incomplete namespace.
	(resolve_where, gfc_resolve_where_code_in_forall,
	gfc_resolve_forall_body, gfc_resolve_code): Check that the op
	code is still EXEC_ASSIGN. If it is set lhs to must finalize.
	(is_finalizable_type): New function.
	(generate_component_assignments): Set must_finalize if needed.
	(gfc_resolve_finalizers): Error if assumed rank finalizer is
	not the only one. Warning on lack of scalar finalizer modified
	to account for assumed rank finalizers.
	(generate_final_call): New function.
	(generate_component_assignments): Enclose the outermost call in
	a block to capture automatic deallocation and final calls.
	Set must_finalize as required to satisfy the standards. Use an
	explicit pointer assignment for pointer components to capture
	finalization of the target. Likewise use explicit assignment
	for allocatable components. Do not use the temporary copy of
	the lhs in defined assignment if the component is allocatable.
	Put the temporary in the same namespace as the lhs symbol if
	the component may be finalized. Remove the leading assignment
	from the expansion of assignment of components that have their
	own defined assignment components. Suppress finalization of
	assignment of temporary components to the lhs. Make an explicit
	final call for the rhs function temporary if it exists.
	(gfc_resolve_code): Set must_finalize for assignments with an
	array constructor on the rhs.
	(gfc_resolve_finalizers): Ensure that an assumed rank finalizer
	is the only finalizer for that type and correct the surprising
	warning for the lack of a scalar finalizer.
	(check_defined_assignments): Handle allocatable components.
	(resolve_fl_derived): Set referenced the vtab for use
	associated symbols.
	(resolve_symbol): Set referenced an unreferenced symbol that
	will be finalized.
	* trans-array.cc (gfc_trans_array_constructor_value): Add code
	to finalize the constructor result. Warn that this feature was
	removed in F2018 and that it is suppressed by -std=2018.
	(trans_array_constructor): Add finalblock, pass to previous
	and apply to loop->post if filled.
	(gfc_add_loop_ss_code): Add se finalblock to outer loop post.
	(gfc_trans_array_cobounds, gfc_trans_array_bounds): Add any
	generated finalization code to the main block.
	(structure_alloc_comps): Add boolean argument to suppress
	finalization and use it for calls from
	gfc_deallocate_alloc_comp_no_caf. Otherwise it defaults to
	false.
	(gfc_copy_alloc_comp_no_fini): New wrapper for
	structure_alloc_comps.
	(gfc_alloc_allocatable_for_assignment): Suppress finalization
	by setting new arg in call to gfc_deallocate_alloc_comp_no_caf.
	(gfc_trans_deferred_array): Use gfc_may_be_finalized and do not
	deallocate the components of entities with a leading '_' in the
	name that are also marked as artificial.
	* trans-array.h : Add the new boolean argument to the prototype
	of gfc_deallocate_alloc_comp_no_caf with a default of false.
	Add prototype for gfc_copy_alloc_comp_no_fini.
	* trans-decl.cc(init_intent_out_dt): Tidy up the code.
	* trans-expr.cc (gfc_init_se): Initialize finalblock.
	(gfc_conv_procedure_call): Use gfc_finalize_tree_expr to
	finalize function results. Replace in-line block for class
	results with call to new function.
	(gfc_conv_expr): Finalize structure constructors for F2003 and
	F2008. Warn that this feature was deleted in F2018 and, unlike
	array constructors, is not default. Add array constructor
	finalblock to the post block.
	(gfc_trans_scalar_assign): Suppress finalization by setting new
	argument in call to gfc_deallocate_alloc_comp_no_caf. Add the
	finalization blocks to the main block.
	(gfc_trans_arrayfunc_assign): Use gfc_assignment_finalizer_call
	and ensure that finalization occurs after the evaluation of the
	rhs but using the initial value for the lhs. Finalize rhs
	function results using gfc_finalize_tree_expr.
	(trans_class_assignment, gfc_trans_assignment_1): As previous
	function, taking care to order evaluation, assignment and
	finalization correctly.
	* trans-io.cc (gfc_trans_transfer): Add the final block.
	* trans-stmt.cc (gfc_trans_call, gfc_trans_allocate): likewise.
	(trans_associate_var): Nullify derived allocatable components
	and finalize function targets with defined assignment
	components on leaving the block scope.
	(trans_allocate): Finalize source expressions, if required,
	and set init_expr artificial temporarily to suppress the
	finalization in gfc_trans_assignment.
	* trans.cc (gfc_add_finalizer_call): Do not finalize the
	temporaries generated in type assignment with defined
	assignment components.
	(gfc_assignment_finalizer_call): New function.
	(gfc_finalize_tree_expr): New function.
	* trans.h: Add finalblock to gfc_se. Add the prototypes for
	gfc_finalize_tree_expr and gfc_assignment_finalizer_call.

gcc/testsuite/
	PR fortran/64290
	* gfortran.dg/finalize_38.f90 : New test.
	* gfortran.dg/finalize_38a.f90 : New test.
	* gfortran.dg/allocate_with_source_25.f90 : The number of final
	calls goes down from 6 to 4.
	* gfortran.dg/associate_25.f90 : Remove the incorrect comment.
	* gfortran.dg/auto_dealloc_2.f90 : Change the tree dump expr
	but the final count remains the same.
	* gfortran.dg/unlimited_polymorphic_8.f90 : Tree dump reveals
	foo.1.x rather than foo.0.x

	PR fortran/67444
	* gfortran.dg/finalize_39.f90 : New test.

	PR fortran/67471
	* gfortran.dg/finalize_40.f90 : New test.

	PR fortran/69298
	PR fortran/70863
	* gfortran.dg/finalize_41.f90 : New test.

	PR fortran/71798
	* gfortran.dg/finalize_42.f90 : New test.

	PR fortran/80524
	* gfortran.dg/finalize_43.f90 : New test.

	PR fortran/82996
	* gfortran.dg/finalize_44.f90 : New test.

	PR fortran/84472
	* gfortran.dg/finalize_45.f90 : New test.

	PR fortran/88735
	PR fortran/93691
	* gfortran.dg/finalize_46.f90 : New test.

	PR fortran/91316
	* gfortran.dg/finalize_47.f90 : New test.

	PR fortran/106576
	* gfortran.dg/finalize_48.f90 : New test.

	PR fortran/37336
	* gfortran.dg/finalize_49.f90 : New test.
	* gfortran.dg/finalize_50.f90 : New test.
	* gfortran.dg/finalize_51.f90 : New test.