Dear all,
the following patch fixes
character(len=:), allocatable :: str
str = repeat('X', n)
Before the patch, the (re)allocation happened before the RHS was
evaluated. Thus, the string length wasn't known! (Work around: Add
parentheses around the function call.)
Note that the patch assumes that the function's result variable's length
specification expression is completely known to the caller. I think
that's always the case in gfortran - or is it not?.
I am not sure whether once can construct a valid program using INTERFACE
where that's not the case. The answer is probably no, given:
"If a type parameter of a function result or a bound of a function
result array is not a constant expression, the exact dependence on the
entities in the expression is a characteristic." (F2008, 12.3.3). --
Nevertheless, one has to think about whether there could be some issue.
If there is, I have no idea how one could handle it instead. Thus, there
be better no issue!
I am also not positive that len=: pointer results are properly handled,
but probably they are. (Untested; character array results are also
untested - and array constructors are known to be broken.)
Comments?
The attached patch builds and regtests.
OK for the trunk?
Tobias
2012-05-11 Tobias Burnus <bur...@net-b.de>
PR fortran/49110
PR fortran/51055
* trans-expr.c (gfc_trans_assignment_1): Fix allocation
handling for assignment of function results to allocatable
deferred-length strings.
2012-05-11 Tobias Burnus <bur...@net-b.de>
PR fortran/49110
PR fortran/51055
* gfortran.dg/deferred_type_param_3.f90: New.
* gfortran.dg/deferred_type_param_4.f90: New.
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 8045b1f..8126697 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -7002,17 +7003,18 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag,
{
tmp = gfc_deallocate_alloc_comp (expr2->ts.u.derived, rse.expr, 0);
gfc_add_expr_to_block (&loop.post, tmp);
}
- /* For a deferred character length function, the function call must
- happen before the (re)allocation of the lhs, otherwise the character
- length of the result is not known. */
- def_clen_func = (((expr2->expr_type == EXPR_FUNCTION)
- || (expr2->expr_type == EXPR_COMPCALL)
- || (expr2->expr_type == EXPR_PPC))
- && expr2->ts.deferred);
+ /* When assigning a character function result to a deferred-length variable,
+ the function call must happen before the (re)allocation of the lhs -
+ otherwise the character length of the result is not known.
+ NOTE: This relies on having the exact dependence of the length type
+ parameter available to the caller; gfortran save it in the .mod files. */
+ def_clen_func = (expr2->expr_type == EXPR_FUNCTION
+ || expr2->expr_type == EXPR_COMPCALL
+ || expr2->expr_type == EXPR_PPC);
if (gfc_option.flag_realloc_lhs
&& expr2->ts.type == BT_CHARACTER
&& (def_clen_func || expr2->expr_type == EXPR_OP)
&& expr1->ts.deferred)
gfc_add_block_to_block (&block, &rse.pre);
--- /dev/null 2012-05-11 07:40:56.923831265 +0200
+++ gcc/gcc/testsuite/gfortran.dg/deferred_type_param_3.f90 2012-05-11 12:18:46.000000000 +0200
@@ -0,0 +1,33 @@
+! { dg-do run }
+!
+! PR fortran/51055
+! PR fortran/49110
+!
+
+subroutine test()
+ implicit none
+ integer :: i = 5
+ character(len=:), allocatable :: s1
+ call sub(s1, i)
+ if (len(s1) /= 5) call abort()
+ if (s1 /= "ZZZZZ") call abort()
+contains
+ subroutine sub(str,j)
+ character(len=:), allocatable :: str
+ integer :: j
+ str = REPEAT("Z",j)
+ if (len(str) /= 5) call abort()
+ if (str /= "ZZZZZ") call abort()
+ end subroutine sub
+end subroutine test
+
+program a
+ character(len=:),allocatable :: s
+ integer :: j=2
+ s = repeat ('x', j)
+ if (len(repeat(' ',j)) /= 2) call abort()
+ if (repeat('y',j) /= "yy") call abort()
+ if (len(s) /= 2) call abort()
+ if (s /= "xx") call abort()
+ call test()
+end program a
--- /dev/null 2012-05-11 07:40:56.923831265 +0200
+++ gcc/gcc/testsuite/gfortran.dg/deferred_type_param_4.f90 2012-05-11 12:22:30.000000000 +0200
@@ -0,0 +1,33 @@
+! { dg-do run }
+!
+! PR fortran/51055
+! PR fortran/49110
+!
+!
+program test
+ implicit none
+ character(len=:), allocatable :: str
+ integer :: i
+ i = 5
+ str = f()
+ call printIt ()
+ i = 7
+ str = repeat('X', i)
+ call printIt ()
+contains
+ function f()
+ character(len=i) :: f
+ f = '1234567890'
+ end function f
+ subroutine printIt
+! print *, len(str)
+! print '(3a)', '>',str,'<'
+ if (i == 5) then
+ if (str /= "12345" .or. len(str) /= 5) call abort ()
+ else if (i == 7) then
+ if (str /= "XXXXXXX" .or. len(str) /= 7) call abort ()
+ else
+ call abort ()
+ end if
+ end subroutine
+end
