This patch checks for negative character length in the array constructor,
and treats it as LEN=0. A warning message is also printed if bounds checking is
enabled.
Bootstrapped and regression tested the patch on x86_64-linux-gnu and
aarch64-linux-gnu.
Index: ChangeLog
===================================================================
--- ChangeLog (revision 242906)
+++ ChangeLog (working copy)
@@ -1,3 +1,9 @@
+2016-11-30 Elizebeth Punnoose <elizebeth.punno...@hpe.com>
+
+ PR fortran/77505
+ * trans-array.c (trans_array_constructor): Treat negative
character
+ length as LEN=0.
+
2016-11-27 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/78474
Index: trans-array.c
===================================================================
--- trans-array.c (revision 242906)
+++ trans-array.c (working copy)
@@ -2226,6 +2226,8 @@ trans_array_constructor (gfc_ss * ss, lo
gfc_ss_info *ss_info;
gfc_expr *expr;
gfc_ss *s;
+ tree neg_len;
+ char *msg;
/* Save the old values for nested checking. */
old_first_len = first_len;
@@ -2271,6 +2273,28 @@ trans_array_constructor (gfc_ss * ss, lo
gfc_conv_expr_type (&length_se, expr->ts.u.cl->length,
gfc_charlen_type_node);
ss_info->string_length = length_se.expr;
+
+ /* Check if the character length is negative,
+ if so consider it as LEN=0. */
+ neg_len = fold_build2_loc (input_location, LT_EXPR,
+
boolean_type_node, ss_info->string_length,
+
build_int_cst (gfc_charlen_type_node, 0));
+ /* Print a warning if bounds checking is enabled. */
+ if (gfc_option.rtcheck & GFC_RTCHECK_BOUNDS)
+ {
+ msg = xasprintf ("Negative character length will be treated"
+ " as LEN=0");
+ gfc_trans_runtime_check (false, true, neg_len, &length_se.pre,
+ where, msg);
+ free (msg);
+ }
+ ss_info->string_length = fold_build3_loc (input_location,
COND_EXPR,
+
gfc_charlen_type_node, neg_len,
+
build_int_cst (gfc_charlen_type_node, 0),
+
ss_info->string_length);
+ ss_info->string_length = gfc_evaluate_now
(ss_info->string_length,
+
&length_se.pre);
+
gfc_add_block_to_block (&outer_loop->pre, &length_se.pre);
gfc_add_block_to_block (&outer_loop->post, &length_se.post);
}
Index: ChangeLog
===================================================================
--- ChangeLog (revision 242906)
+++ ChangeLog (working copy)
@@ -1,3 +1,9 @@
+2016-11-30 Elizebeth Punnoose <elizebeth.punno...@hpe.com>
+
+ PR fortran/77505
+ * gfortran.dg/pr77505_1.f90: New test.
+ * gfortran.dg/pr77505_2.f90: New test.
+
2016-11-27 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/78474
Index: pr77505_1.f90
===================================================================
--- pr77505_1.f90 (nonexistent)
+++ pr77505_1.f90 (working copy)
@@ -0,0 +1,13 @@
+! { dg-do run }
+program rabbithole
+implicit none
+character(len=:),allocatable :: text_block(:)
+integer :: i
+integer :: ii
+character(len=10) :: cten='abcdefghij'
+character(len=20) :: ctwenty='abcdefghijabcdefghij'
+ii=-6
+text_block=[ character(len=ii) :: cten, ctwenty ]
+write(*,*)'WRITE IT'
+write(*,'(a)')(trim(text_block(i)),i=1,size(text_block))
+end program rabbithole
Index: pr77505_2.f90
===================================================================
--- pr77505_2.f90 (nonexistent)
+++ pr77505_2.f90 (working copy)
@@ -0,0 +1,14 @@
+! { dg-options "-fcheck=bounds" }
+! { dg-do run }
+program rabbithole
+implicit none
+character(len=:),allocatable :: text_block(:)
+integer :: i
+integer :: ii
+character(len=10) :: cten='abcdefghij'
+character(len=20) :: ctwenty='abcdefghijabcdefghij'
+ii=-6
+text_block=[ character(len=ii) :: cten, ctwenty ]
+write(*,*)'WRITE IT'
+write(*,'(a)')(trim(text_block(i)),i=1,size(text_block))
+end program rabbithole
Thanks,
Elizebeth
