Several attempts, including mine, were made to fix this bug since it
was posted. They were all attacking the wrong place. Instead of
providing the free of the class _data as part of the call to
'add_a_type' it should be included in the post block of the argument
processing in the call to 'assign_a_type'. The comment in the patch
says the rest.
Bootstrapped and regtested on FC28/x86_64 - OK for trunk?
Paul
2017-07-27 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/80477
* trans-expr.c (gfc_conv_procedure_call): Allocatable class
results being passed to a derived type formal argument must
have the _data component deallocated after use.
2017-07-27 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/80477
* gfortran.dg/class_result_7.f90: New test.
Index: gcc/fortran/trans-expr.c
===================================================================
*** gcc/fortran/trans-expr.c (revision 262444)
--- gcc/fortran/trans-expr.c (working copy)
*************** gfc_conv_procedure_call (gfc_se * se, gf
*** 5360,5366 ****
&& e->ts.type == BT_CLASS
&& !CLASS_DATA (e)->attr.dimension
&& !CLASS_DATA (e)->attr.codimension)
! parmse.expr = gfc_class_data_get (parmse.expr);
/* Wrap scalar variable in a descriptor. We need to convert
the address of a pointer back to the pointer itself before,
--- 5360,5384 ----
&& e->ts.type == BT_CLASS
&& !CLASS_DATA (e)->attr.dimension
&& !CLASS_DATA (e)->attr.codimension)
! {
! parmse.expr = gfc_class_data_get (parmse.expr);
! /* The result is a class temporary, whose _data component
! must be freed to avoid a memory leak. */
! if (e->expr_type == EXPR_FUNCTION
! && CLASS_DATA (e)->attr.allocatable)
! {
! tree zero;
! zero = build_int_cst (TREE_TYPE (parmse.expr), 0);
! tmp = fold_build2_loc (input_location, NE_EXPR,
! logical_type_node,
! parmse.expr, zero);
! tmp = build3_v (COND_EXPR, tmp,
! gfc_call_free (parmse.expr),
! build_empty_stmt (input_location));
! gfc_add_expr_to_block (&parmse.post, tmp);
! gfc_add_modify (&parmse.post, parmse.expr, zero);
! }
! }
/* Wrap scalar variable in a descriptor. We need to convert
the address of a pointer back to the pointer itself before,
Index: gcc/testsuite/gfortran.dg/class_result_7.f90
===================================================================
*** gcc/testsuite/gfortran.dg/class_result_7.f90 (nonexistent)
--- gcc/testsuite/gfortran.dg/class_result_7.f90 (working copy)
***************
*** 0 ****
--- 1,36 ----
+ ! { dg-do compile }
+ ! { dg-options "-fdump-tree-original" }
+ !
+ ! Test the fix for PR80477
+ !
+ ! Contributed by Stefano Zaghi <stefano.za...@cnr.it>
+ !
+ module a_type_m
+ implicit none
+ type :: a_type_t
+ real :: x
+ endtype
+ contains
+ subroutine assign_a_type(lhs, rhs)
+ type(a_type_t), intent(inout) :: lhs
+ type(a_type_t), intent(in) :: rhs
+ lhs%x = rhs%x
+ end subroutine
+
+ function add_a_type(lhs, rhs) result( res )
+ type(a_type_t), intent(in) :: lhs
+ type(a_type_t), intent(in) :: rhs
+ class(a_type_t), allocatable :: res
+ allocate (a_type_t :: res)
+ res%x = lhs%x + rhs%x
+ end function
+ end module
+
+ program polymorphic_operators_memory_leaks
+ use a_type_m
+ implicit none
+ type(a_type_t) :: a = a_type_t(1) , b = a_type_t(2)
+ call assign_a_type (a, add_a_type(a,b)) ! generated a memory leak
+ end
+ ! { dg-final { scan-tree-dump-times "builtin_free" 1 "original" } }
+ ! { dg-final { scan-tree-dump-times "builtin_malloc" 1 "original" } }
Index: gcc/testsuite/gfortran.dg/transfer_class_3.f90
===================================================================
