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* [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
@ 2022-06-13 20:18 eggert at cs dot ucla.edu
2022-06-13 20:27 ` [Bug analyzer/105961] " dmalcolm at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: eggert at cs dot ucla.edu @ 2022-06-13 20:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
Bug ID: 105961
Summary: -Wanalyzer-use-of-uninitialized-value false positive
after "= {0}"
Product: gcc
Version: 12.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: eggert at cs dot ucla.edu
Target Milestone: ---
This is gcc (GCC) 12.1.1 20220507 (Red Hat 12.1.1-1) on x86-64. I do not
observe the bug with gcc-12 (Ubuntu 12-20220319-1ubuntu1) 12.0.1 20220319
(experimental) [master r12-7719-g8ca61ad148f] on x86-64.
Compile the attached program (derived from bleeding-edge Emacs) with:
gcc -O2 -S -fanalyzer t.i
GCC complains:
In function ‘dump_mmap_release’,
inlined from ‘pdumper_load’ at t.i:50527:5:
t.i:49512:10: warning: use of uninitialized value ‘sections[i].release’
[CWE-457] [-Wanalyzer-use-of-uninitialized-value]
49512 | if (map->release)
| ~~~^~~~~~~~~
‘pdumper_load’: events 1-9
|
|50318 | pdumper_load (const char *dump_filename, char *argv0)
| | ^~~~~~~~~~~~
| | |
| | (1) entry to ‘pdumper_load’
|......
|50331 | struct dump_memory_map sections[NUMBER_DUMP_SECTIONS] = { 0 };
| | ~~~~~~~~
| | |
| | (2) region created on stack here
|......
The region is obviously initialized, via the "= { 0 }" at the end. The
following change pacifies GCC, but should not be necessary.
--- t.i 2022-06-13 13:06:59.000000000 -0700
+++ u.i 2022-06-13 13:09:18.000000000 -0700
@@ -50329,6 +50329,7 @@
struct dump_header header_buf = { 0 };
struct dump_header *header = &header_buf;
struct dump_memory_map sections[NUMBER_DUMP_SECTIONS] = { 0 };
+ memset (sections, 0, sizeof sections);
const struct timespec start_time = current_timespec ();
char *dump_filename_copy;
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/105961] -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
@ 2022-06-13 20:27 ` dmalcolm at gcc dot gnu.org
2022-06-13 20:36 ` eggert at cs dot ucla.edu
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2022-06-13 20:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
(In reply to eggert from comment #0)
[...snip...]
> Compile the attached program (derived from bleeding-edge Emacs) with:
I'm not seeing an attachment - do you still have this file, and can you try
attaching it again please?
Thanks!
[...snip...]
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/105961] -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
2022-06-13 20:27 ` [Bug analyzer/105961] " dmalcolm at gcc dot gnu.org
@ 2022-06-13 20:36 ` eggert at cs dot ucla.edu
2022-06-13 20:47 ` dmalcolm at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: eggert at cs dot ucla.edu @ 2022-06-13 20:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
--- Comment #2 from eggert at cs dot ucla.edu ---
Created attachment 53131
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53131&action=edit
reproducer for the bug (compressed with xz)
The uncompressed t.i was too large for bugzilla, so here's the same file,
compressed with xz.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/105961] -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
2022-06-13 20:27 ` [Bug analyzer/105961] " dmalcolm at gcc dot gnu.org
2022-06-13 20:36 ` eggert at cs dot ucla.edu
@ 2022-06-13 20:47 ` dmalcolm at gcc dot gnu.org
2022-06-13 22:16 ` dmalcolm at gcc dot gnu.org
2024-02-16 14:13 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2022-06-13 20:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2022-06-13
Ever confirmed|0 |1
--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks - I can see the reproduce the bug with that (tested with trunk).
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/105961] -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
` (2 preceding siblings ...)
2022-06-13 20:47 ` dmalcolm at gcc dot gnu.org
@ 2022-06-13 22:16 ` dmalcolm at gcc dot gnu.org
2024-02-16 14:13 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2022-06-13 22:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
--- Comment #4 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
As well as the false positive, the diagnostic path is rather unreadable due to
inlining. I've filed a separate bug about this (PR 105962).
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug analyzer/105961] -Wanalyzer-use-of-uninitialized-value false positive after "= {0}"
2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
` (3 preceding siblings ...)
2022-06-13 22:16 ` dmalcolm at gcc dot gnu.org
@ 2024-02-16 14:13 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2024-02-16 14:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105961
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |WORKSFORME
--- Comment #5 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
I tried this again on Compiler Explorer, but I'm now not seeing any output on
the reproducer:
Trunk: https://godbolt.org/z/G8fravbbT
GCC 13.2: https://godbolt.org/z/8aj7zTssG
GCC 12.3: https://godbolt.org/z/6v15Es3nc
GCC 11.4: https://godbolt.org/z/hxPdxGTr9
Marking as RESOLVED WORKSFORME. Feel free to reopen if you're still able to
reproduce this.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-02-16 14:13 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-13 20:18 [Bug analyzer/105961] New: -Wanalyzer-use-of-uninitialized-value false positive after "= {0}" eggert at cs dot ucla.edu
2022-06-13 20:27 ` [Bug analyzer/105961] " dmalcolm at gcc dot gnu.org
2022-06-13 20:36 ` eggert at cs dot ucla.edu
2022-06-13 20:47 ` dmalcolm at gcc dot gnu.org
2022-06-13 22:16 ` dmalcolm at gcc dot gnu.org
2024-02-16 14:13 ` dmalcolm at gcc dot gnu.org
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