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| author | Stefan Schulze Frielinghaus <stefansf@linux.ibm.com> | 2020-04-28 13:14:28 +0200 |
|---|---|---|
| committer | Stefan Schulze Frielinghaus <stefansf@linux.ibm.com> | 2020-04-29 16:37:18 +0200 |
| commit | 27594524d8a93cddb197ad8c9d4075c5870f1473 (patch) | |
| tree | aa6f9d166bf0d9c88a006852b9c173c6890af7c0 /gcc/fortran | |
| parent | 392aa7d7adfbd84253121d2ef779bf3c627e8d0b (diff) | |
| download | gcc-27594524d8a93cddb197ad8c9d4075c5870f1473.zip gcc-27594524d8a93cddb197ad8c9d4075c5870f1473.tar.gz gcc-27594524d8a93cddb197ad8c9d4075c5870f1473.tar.bz2 | |
fortran/io.c: Fix use of uninitialized variable num [PR94769]
While bootstrapping GCC on S/390 the following warning occurs:
gcc/fortran/io.c: In function 'bool gfc_resolve_dt(gfc_code*, gfc_dt*, locus*)':
gcc/fortran/io.c:3857:7: error: 'num' may be used uninitialized in this function [-Werror=maybe-uninitialized]
3857 | if (num == 0)
| ^~
gcc/fortran/io.c:3843:11: note: 'num' was declared here
3843 | int num;
Since gfc_resolve_dt is a non-static function we cannot assume anything about
argument DT. Argument DT gets passed to function check_io_constraints which
passes values depending on DT, namely dt->asynchronous->value.character.string
to function compare_to_allowed_values as well as argument warn which is true as
soon as DT->dterr is true. Thus both arguments depend on DT.
If function compare_to_allowed_values is called with
dt->asynchronous->value.character.string not being an allowed value, and
ALLOWED_F2003 as well as ALLOWED_GNU being NULL (which is the case at the
particular call side), and WARN equals true, then the function returns with a
non-zero value and leaves num uninitialized which renders the warning true.
Initialized num to -1 and added an assert statement.
gcc/fortran/ChangeLog:
2020-04-29 Stefan Schulze Frielinghaus <stefansf@linux.ibm.com>
PR fortran/94769
* io.c (check_io_constraints): Initialize local variable num to
-1 and assert that it receives a meaningful value by function
compare_to_allowed_values.
Diffstat (limited to 'gcc/fortran')
| -rw-r--r-- | gcc/fortran/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/fortran/io.c | 4 |
2 files changed, 10 insertions, 1 deletions
diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog index 1e6b593..f245cb4 100644 --- a/gcc/fortran/ChangeLog +++ b/gcc/fortran/ChangeLog @@ -1,3 +1,10 @@ +2020-04-29 Stefan Schulze Frielinghaus <stefansf@linux.ibm.com> + + PR fortran/94769 + * io.c (check_io_constraints): Initialize local variable num to + -1 and assert that it receives a meaningful value by function + compare_to_allowed_values. + 2020-04-27 Thomas Koenig <tkoenig@gcc.gnu.org> PR fortran/93956 diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c index e066666..981cf9e 100644 --- a/gcc/fortran/io.c +++ b/gcc/fortran/io.c @@ -3840,7 +3840,7 @@ if (condition) \ if (dt->asynchronous) { - int num; + int num = -1; static const char * asynchronous[] = { "YES", "NO", NULL }; /* Note: gfc_reduce_init_expr reports an error if not init-expr. */ @@ -3853,6 +3853,8 @@ if (condition) \ io_kind_name (k), warn, &dt->asynchronous->where, &num)) return false; + gcc_checking_assert (num != -1); + /* For "YES", mark related symbols as asynchronous. */ if (num == 0) { |