On Wed, Nov 30, 2016 at 05:13:28AM +0000, Punnoose, Elizebeth wrote:
> Please excuse the messy formatting in my initial mail. Resending
> with proper formatting.
>
> 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.
>
Thanks. After regression testing on x86_64-*-freebsd, I committed
the attached patch. Not sure if the whitespace got messed up by
my email agent, but I needed to reformat your testcases. I took the
opportunity to rename and improve the testcases. The improvements
check that in fact len=0 and that a warning is issued.
Hopefully, you're inclined to submit additional patches in the future.
A few recommendations are to include the text of your ChangeLog
entry in body of the email, for example,
2016-12-01 Elizebeth Punnoose <elizebeth.punno...@hpe.com>
PR fortran/77505
* trans-array.c (trans_array_constructor): Treat negative character
length as LEN = 0.
2016-12-01 Elizebeth Punnoose <elizebeth.punno...@hpe.com>
PR fortran/77505
* gfortran.dg/char_length_20.f90: New test.
* gfortran.dg/char_length_21.f90: Ditto.
(Note, 2 spaces before and after your name.) Then attach the
patch to the email. This hopefully will prevent formatting
issues with various email clients/servers.
--
Steve
Index: gcc/fortran/trans-array.c
===================================================================
--- gcc/fortran/trans-array.c (revision 243134)
+++ gcc/fortran/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 +2273,29 @@ 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 it is, then
+ set 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 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: gcc/testsuite/gfortran.dg/char_length_20.f90
===================================================================
--- gcc/testsuite/gfortran.dg/char_length_20.f90 (nonexistent)
+++ gcc/testsuite/gfortran.dg/char_length_20.f90 (working copy)
@@ -0,0 +1,13 @@
+! { dg-do run }
+! { dg-options "-fcheck=bounds" }
+program rabbithole
+ implicit none
+ character(len=:), allocatable :: text_block(:)
+ integer i, ii
+ character(len=10) :: cten='abcdefghij'
+ character(len=20) :: ctwenty='abcdefghijabcdefghij'
+ ii = -6
+ text_block=[ character(len=ii) :: cten, ctwenty ]
+ if (any(len_trim(text_block) /= 0)) call abort
+end program rabbithole
+! { dg-output "At line 10 of file .*char_length_20.f90.*Fortran runtime warning: Negative character length treated as LEN = 0" }
Index: gcc/testsuite/gfortran.dg/char_length_21.f90
===================================================================
--- gcc/testsuite/gfortran.dg/char_length_21.f90 (nonexistent)
+++ gcc/testsuite/gfortran.dg/char_length_21.f90 (working copy)
@@ -0,0 +1,11 @@
+! { dg-do run }
+program rabbithole
+ implicit none
+ character(len=:), allocatable :: text_block(:)
+ integer i, ii
+ character(len=10) :: cten='abcdefghij'
+ character(len=20) :: ctwenty='abcdefghijabcdefghij'
+ ii = -6
+ text_block = [character(len=ii) :: cten, ctwenty]
+ if (any(len_trim(text_block) /= 0)) call abort
+end program rabbithole
