https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116864
Bug ID: 116864
Summary: "*<unknown>" and "......" in false positive
-Wanalyzer-use-of-uninitialized-value
Product: gcc
Version: 14.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: eggert at cs dot ucla.edu
Target Milestone: ---
Created attachment 59213
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59213&action=edit
gunzip and compile with "gcc -O2 -S -fanalyzer" on x86-64 to see the bug
Normally coreutils isn't compiled with -fanalyzer, but I recently tried it (by
using './configure --enable-gcc-warnings=expensive') and quickly gave up
because there were too many false positives.
I'm reporting the first false positive. At least I *think* it's a false
positive: the diagnostic is so puzzling and gives so few details that it's hard
to see what GCC is complaining about.
This is gcc (GCC) 14.2.1 20240912 (Red Hat 14.2.1-3) on x86-64. Decompress and
compile the attached file t.i.gz with:
gunzip t.i.gz
gcc -O2 -S -fanalyzer t.i
GCC outputs the following, which I can't decipher, as all the details are
listed as "*<unknown>" or "......".
parse-datetime.c: In function ‘yyparse’:
parse-datetime.c:1820:9: warning: use of uninitialized value ‘*<unknown>’
[CWE-457] [-Wanalyzer-use-of-uninitialized-value]
‘parse_datetime’: events 1-2
|
|parse-datetime.y:2395:1:
|......
|
‘parse_datetime’: events 3-4
|
|parse-datetime.y:2402:12:
|
+--> ‘parse_datetime_body’: event 5
|
|parse-datetime.y:1739:1:
|
‘parse_datetime_body’: events 6-8
|
|parse-datetime.y:1821:6:
|......
|......
|
‘parse_datetime_body’: event 9
|
|parse-datetime.y:1841:18:
|
‘parse_datetime_body’: event 10
|
|parse-datetime.y:1870:3:
|
+--> ‘populate_local_time_zone_table’: event 11
|
|parse-datetime.y:1577:1:
|
‘populate_local_time_zone_table’: events 12-13
|
|parse-datetime.y:1590:6:
|......
|
<------+
|
‘parse_datetime_body’: events 14-15
|
|parse-datetime.y:1870:3:
|......
|
‘parse_datetime_body’: event 16
|
|parse-datetime.y:1877:19:
|
‘parse_datetime_body’: event 17
|
|parse-datetime.y:1902:7:
|
+--> ‘yyparse’: events 18-20
|
|parse-datetime.c:1572:1:
|......
|......
|
‘yyparse’: events 21-28
|
|parse-datetime.c:1715:6:
|......
|......
|......
|......
|
+--> ‘yylex’: event 29
|
|parse-datetime.y:1416:1:
|
‘yylex’: event 30
|
|parse-datetime.y:1518:16:
|
+--> ‘lookup_word’: event 31
|
|parse-datetime.y:1348:1:
|
‘lookup_word’: events 32-34
|
|parse-datetime.y:1361:29:
|
‘lookup_word’: event 35
|
|cc1:
| (35): ...to here
|
<------+
|
‘yylex’: events 36-37
|
|parse-datetime.y:1518:16:
|
‘yylex’: event 38
|
|parse-datetime.y:1525:29:
|
<------+
|
‘yyparse’: events 39-49
|
|parse-datetime.c:1739:16:
|......
|......
|......
|......
|
‘yyparse’: events 50-51
|
|parse-datetime.c:1800:6:
|
‘yyparse’: event 52
|
|parse-datetime.c:1820:9:
|
