Bug#983868: gsequencer ftbfs with -Werror=maybe-uninitialized
Hi,
I just tested with gcc-9, the patch should fix the problems with
ags_midi_buffer_util.c.
I would call it a false positive, it is good that GCC complains but it
doesn't actually
know how a MIDI parser is implemented.
If you need a higher-level API, I recommend you:
http://git.savannah.nongnu.org/cgit/gsequencer.git/tree/ags/audio/midi/ags_midi_parser.h?h=3.7.x
I am going to provide another tarball including this fix.
regards,
Joël
On Wed, Mar 3, 2021 at 9:08 AM Matthias Klose <doko@debian.org> wrote:
>
> Well, that's not what the GCC developers think. The warning is there in GCC 9
> and GCC 11 as well. The name of the option even implies that this is a "maybe".
> Forcing it to become an error with -Werror might be wrong, so if you build with
> -Werrer, build with -Wno-error=maybe-uninitialized as well.
>
> On 3/2/21 3:46 PM, Joël Krähemann wrote:
> > Hi,
> >
> > This is not a GSequencer bug!
> >
> > This behavior is wanted.
> >
> > delta_time was properly initialized in ags_midi_buffer_util_seek_message().
> >
> > it would be wrong if delta_time was overridden by
> > ags_midi_buffer_util_get_varlength().
> > it does only return 0 length so varlength shall not be set.
> >
> > If you output 0 length, this means you can't use return location, so why
> > should I set it?
> >
> > regards,
> > Joël
> >
> > On Tue, Mar 2, 2021 at 1:45 PM Matthias Klose <doko@debian.org> wrote:
> >>
> >> Package: src:gsequencer
> >> Version: 3.7.38-1
> >> Severity: important
> >> Tags: sid bullseye
> >> X-Debbugs-CC: Joël Krähemann <jkraehemann@gmail.com>
> >>
> >> gsequencer ftbfs with -Werror=maybe-uninitialized, with gcc-10 and gcc-11 from
> >> experimental.
> >>
> >> ags/audio/midi/ags_midi_buffer_util.c:2606:17: error: ‘current_delta_time’ may
> >> be used uninitialized in this function [-Werror=maybe-uninitialized]
> >> 2606 | *delta_time = current_delta_time;
> >> | ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
> >> cc1: some warnings being treated as errors
> >>
> >> You don't see the error in a build log, because the libtool output is redirected
> >> to /dev/null.
> >>
> >> Forwarded to https://gcc.gnu.org/PR99340
> >>
> >> The warning is only seen with -fPIE, not -fPIC, which is a bug in GCC.
> >>
> >> The warning itself is correct, ags_midi_buffer_util_get_varlength doesn't always
> >> return a value in varlength.
>
diff --git a/ags/audio/midi/ags_midi_buffer_util.c b/ags/audio/midi/ags_midi_buffer_util.c
index 3121d60a0..12dae5d15 100644
--- a/ags/audio/midi/ags_midi_buffer_util.c
+++ b/ags/audio/midi/ags_midi_buffer_util.c
@@ -132,6 +132,10 @@ ags_midi_buffer_util_get_varlength(guchar *buffer,
char c;
if(buffer == NULL){
+ if(varlength != NULL){
+ *varlength = 0;
+ }
+
return(0);
}
@@ -192,6 +196,10 @@ ags_midi_buffer_util_get_int16(guchar *buffer,
glong tmp;
if(buffer == NULL){
+ if(val != NULL){
+ *val = 0;
+ }
+
return;
}
@@ -241,6 +249,10 @@ ags_midi_buffer_util_get_int24(guchar *buffer,
glong tmp;
if(buffer == NULL){
+ if(val != NULL){
+ *val = 0;
+ }
+
return;
}
@@ -292,6 +304,10 @@ ags_midi_buffer_util_get_int32(guchar *buffer,
glong tmp;
if(buffer == NULL){
+ if(val != NULL){
+ *val = 0;
+ }
+
return;
}
@@ -369,9 +385,26 @@ ags_midi_buffer_util_get_header(guchar *buffer,
{
static gchar header[] = "MThd";
- if(g_ascii_strncasecmp(buffer,
- header,
- 4)){
+ if(buffer == NULL ||
+ (!g_ascii_strncasecmp(buffer,
+ header,
+ 4)) == FALSE){
+ if(offset != NULL){
+ *offset = 0;
+ }
+
+ if(format != NULL){
+ *format = 0;
+ }
+
+ if(track_count != NULL){
+ *track_count = 0;
+ }
+
+ if(division != NULL){
+ *division = 0;
+ }
+
return(0);
}
@@ -438,13 +471,14 @@ ags_midi_buffer_util_get_track(guchar *buffer,
{
static gchar track[] = "MTrk";
- if(buffer == NULL){
- return(0);
- }
-
- if(g_ascii_strncasecmp(buffer,
- track,
- 4)){
+ if(buffer == NULL ||
+ (!g_ascii_strncasecmp(buffer,
+ track,
+ 4)) == FALSE){
+ if(offset != NULL){
+ *offset = 0;
+ }
+
return(0);
}
@@ -520,6 +554,22 @@ ags_midi_buffer_util_get_key_on(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(key != NULL){
+ *key = 0;
+ }
+
+ if(velocity != NULL){
+ *velocity = 0;
+ }
+
return(0);
}
@@ -615,6 +665,22 @@ ags_midi_buffer_util_get_key_off(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(key != NULL){
+ *key = 0;
+ }
+
+ if(velocity != NULL){
+ *velocity = 0;
+ }
+
return(0);
}
@@ -710,6 +776,22 @@ ags_midi_buffer_util_get_key_pressure(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(key != NULL){
+ *key = 0;
+ }
+
+ if(pressure != NULL){
+ *pressure = 0;
+ }
+
return(0);
}
@@ -805,6 +887,22 @@ ags_midi_buffer_util_get_change_parameter(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(control != NULL){
+ *control = 0;
+ }
+
+ if(value != NULL){
+ *value = 0;
+ }
+
return(0);
}
@@ -900,6 +998,22 @@ ags_midi_buffer_util_get_pitch_bend(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(pitch != NULL){
+ *pitch = 0;
+ }
+
+ if(transmitter != NULL){
+ *transmitter = 0;
+ }
+
return(0);
}
@@ -988,6 +1102,18 @@ ags_midi_buffer_util_get_change_program(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(program != NULL){
+ *program = 0;
+ }
+
return(0);
}
@@ -1071,6 +1197,18 @@ ags_midi_buffer_util_get_change_pressure(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(channel != NULL){
+ *channel = 0;
+ }
+
+ if(pressure != NULL){
+ *pressure = 0;
+ }
+
return(0);
}
@@ -1157,6 +1295,18 @@ ags_midi_buffer_util_get_sysex(guchar *buffer,
guint i;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(data != NULL){
+ *data = NULL;
+ }
+
+ if(length != NULL){
+ *length = 0;
+ }
+
return(0);
}
@@ -1249,6 +1399,18 @@ ags_midi_buffer_util_get_quarter_frame(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(message_type != NULL){
+ *message_type = 0;
+ }
+
+ if(values != NULL){
+ *values = 0;
+ }
+
return(0);
}
@@ -1326,6 +1488,14 @@ ags_midi_buffer_util_get_song_position(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(song_position != NULL){
+ *song_position = 0;
+ }
+
return(0);
}
@@ -1400,6 +1570,14 @@ ags_midi_buffer_util_get_song_select(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(song_select != NULL){
+ *song_select = 0;
+ }
+
return(0);
}
@@ -1465,6 +1643,10 @@ ags_midi_buffer_util_get_tune_request(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
return(0);
}
@@ -1540,6 +1722,14 @@ ags_midi_buffer_util_get_sequence_number(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(sequence != NULL){
+ *sequence = 0;
+ }
+
return(0);
}
@@ -1640,6 +1830,30 @@ ags_midi_buffer_util_get_smtpe(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(rr != NULL){
+ *rr = 0;
+ }
+
+ if(hr != NULL){
+ *hr = 0;
+ }
+
+ if(mn != NULL){
+ *mn = 0;
+ }
+
+ if(se != NULL){
+ *se = 0;
+ }
+
+ if(fr != NULL){
+ *fr = 0;
+ }
+
return(0);
}
@@ -1740,6 +1954,14 @@ ags_midi_buffer_util_get_tempo(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(tempo != NULL){
+ *tempo = 0;
+ }
+
return(0);
}
@@ -1833,6 +2055,26 @@ ags_midi_buffer_util_get_time_signature(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(nn != NULL){
+ *nn = 0;
+ }
+
+ if(dd != NULL){
+ *dd = 0;
+ }
+
+ if(cc != NULL){
+ *cc = 0;
+ }
+
+ if(bb != NULL){
+ *bb = 0;
+ }
+
return(0);
}
@@ -1932,6 +2174,18 @@ ags_midi_buffer_util_get_key_signature(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(sf != NULL){
+ *sf = 0;
+ }
+
+ if(mi != NULL){
+ *mi = 0;
+ }
+
return(0);
}
@@ -2033,6 +2287,22 @@ ags_midi_buffer_util_get_sequencer_meta_event(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(len != NULL){
+ *len = 0;
+ }
+
+ if(id != NULL){
+ *id = 0;
+ }
+
+ if(data != NULL){
+ *data = 0;
+ }
+
return(0);
}
@@ -2134,6 +2404,18 @@ ags_midi_buffer_util_get_text_event(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
+ if(text != NULL){
+ *text = NULL;
+ }
+
+ if(length != NULL){
+ *length = 0;
+ }
+
return(0);
}
@@ -2214,6 +2496,10 @@ ags_midi_buffer_util_get_end_of_track(guchar *buffer,
guint delta_time_size;
if(buffer == NULL){
+ if(delta_time != NULL){
+ *delta_time = 0;
+ }
+
return(0);
}
@@ -2250,7 +2536,7 @@ ags_midi_buffer_util_seek_message(guchar *buffer,
guchar *offset;
- glong current_delta_time;
+ glong current_delta_time, tmp_delta_time;
glong next_delta_time;
guint delta_time_size;
guchar status, prev_status;
@@ -2291,8 +2577,14 @@ ags_midi_buffer_util_seek_message(guchar *buffer,
}
/* read delta time */
+ tmp_delta_time = 0;
+
delta_time_size = ags_midi_buffer_util_get_varlength(offset,
- ¤t_delta_time);
+ &tmp_delta_time);
+
+ if(delta_time_size > 0){
+ current_delta_time = tmp_delta_time;
+ }
/* read status byte */
status = offset[delta_time_size];
@@ -2365,6 +2657,8 @@ ags_midi_buffer_util_seek_message(guchar *buffer,
offset += n;
/* check if status is omitted */
+ next_delta_time = 0;
+
delta_time_size = ags_midi_buffer_util_get_varlength(offset,
&next_delta_time);
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