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* [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code
@ 2020-04-01 16:10 dmalcolm at gcc dot gnu.org
2020-04-28 13:26 ` [Bug analyzer/94447] " cvs-commit at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2020-04-01 16:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94447
Bug ID: 94447
Summary: Not handling CONSTRUCTOR tree code
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Target Milestone: ---
Consider e.g.:
struct foo
{
int *v;
};
int test (void)
{
struct foo f = {};
return *f.v;
}
This currently reports
t.c: In function ‘test’:
t.c:9:10: warning: use of uninitialized value ‘<unknown>’ [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
9 | return *f.v;
| ^~~~
‘test’: event 1
|
|
when it should be a NULL dereference.
The f = {}; shows up as f = {}; in the gimple dump, a CONSTRUCTOR, and
region_model::on_assignment is hitting a TODO for that tree code.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug analyzer/94447] Not handling CONSTRUCTOR tree code
2020-04-01 16:10 [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code dmalcolm at gcc dot gnu.org
@ 2020-04-28 13:26 ` cvs-commit at gcc dot gnu.org
2020-04-28 13:36 ` dmalcolm at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-04-28 13:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94447
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:
https://gcc.gnu.org/g:78b9783774bfd3540f38f5b1e3c7fc9f719653d7
commit r10-8012-g78b9783774bfd3540f38f5b1e3c7fc9f719653d7
Author: David Malcolm <dmalcolm@redhat.com>
Date: Thu Apr 23 21:31:22 2020 -0400
analyzer: remove -Wanalyzer-use-of-uninitialized-value for GCC 10
From what I can tell -Wanalyzer-use-of-uninitialized-value has not
yet found a true diagnostic in real-world code, and seems to be
particularly susceptible to false positives. These relate to bugs in
the region_model code.
For GCC 10 it seems best to remove this warning, which this patch does.
Internally it also removes POISON_KIND_UNINIT.
I'm working on a rewrite of the region_model code for GCC 11 that I
hope will fix these issues, and allow this warning to be reintroduced.
gcc/analyzer/ChangeLog:
PR analyzer/94447
PR analyzer/94639
PR analyzer/94732
PR analyzer/94754
* analyzer.opt (Wanalyzer-use-of-uninitialized-value): Delete.
* program-state.cc (selftest::test_program_state_dumping): Update
expected dump result for removal of "uninit".
* region-model.cc (poison_kind_to_str): Delete POISON_KIND_UNINIT
case.
(root_region::ensure_stack_region): Initialize stack with null
svalue_id rather than with a typeless POISON_KIND_UNINIT value.
(root_region::ensure_heap_region): Likewise for the heap.
(region_model::dump_summary_of_rep_path_vars): Remove
summarization of uninit values.
(region_model::validate): Remove check that the stack has a
POISON_KIND_UNINIT value.
(poisoned_value_diagnostic::emit): Remove POISON_KIND_UNINIT
case.
(poisoned_value_diagnostic::describe_final_event): Likewise.
(selftest::test_dump): Update expected dump result for removal of
"uninit".
(selftest::test_svalue_equality): Remove "uninit" and "freed".
* region-model.h (enum poison_kind): Remove POISON_KIND_UNINIT.
gcc/ChangeLog:
PR analyzer/94447
PR analyzer/94639
PR analyzer/94732
PR analyzer/94754
* doc/invoke.texi (Static Analyzer Options): Remove
-Wanalyzer-use-of-uninitialized-value.
(-Wno-analyzer-use-of-uninitialized-value): Remove item.
gcc/testsuite/ChangeLog:
PR analyzer/94447
PR analyzer/94639
PR analyzer/94732
PR analyzer/94754
* gcc.dg/analyzer/data-model-1.c: Mark "use of uninitialized
value" warnings as xfail for now.
* gcc.dg/analyzer/data-model-5b.c: Remove uninitialized warning.
* gcc.dg/analyzer/pr94099.c: Mark "uninitialized" warning as xfail
for now.
* gcc.dg/analyzer/pr94447.c: New test.
* gcc.dg/analyzer/pr94639.c: New test.
* gcc.dg/analyzer/pr94732.c: New test.
* gcc.dg/analyzer/pr94754.c: New test.
* gcc.dg/analyzer/zlib-6.c: Mark "uninitialized" warning as xfail
for now.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug analyzer/94447] Not handling CONSTRUCTOR tree code
2020-04-01 16:10 [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code dmalcolm at gcc dot gnu.org
2020-04-28 13:26 ` [Bug analyzer/94447] " cvs-commit at gcc dot gnu.org
@ 2020-04-28 13:36 ` dmalcolm at gcc dot gnu.org
2020-05-08 13:14 ` dmalcolm at gcc dot gnu.org
2020-08-18 0:59 ` dmalcolm at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2020-04-28 13:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94447
--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
r10-8012-g78b9783774bfd3540f38f5b1e3c7fc9f719653d7 removes the false positive,
but we should still handle CONSTRUCTOR tree nodes. Keeping this open.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug analyzer/94447] Not handling CONSTRUCTOR tree code
2020-04-01 16:10 [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code dmalcolm at gcc dot gnu.org
2020-04-28 13:26 ` [Bug analyzer/94447] " cvs-commit at gcc dot gnu.org
2020-04-28 13:36 ` dmalcolm at gcc dot gnu.org
@ 2020-05-08 13:14 ` dmalcolm at gcc dot gnu.org
2020-08-18 0:59 ` dmalcolm at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2020-05-08 13:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94447
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |tommy-gccbugs at thorn dot ws
--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
*** Bug 94999 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug analyzer/94447] Not handling CONSTRUCTOR tree code
2020-04-01 16:10 [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code dmalcolm at gcc dot gnu.org
` (2 preceding siblings ...)
2020-05-08 13:14 ` dmalcolm at gcc dot gnu.org
@ 2020-08-18 0:59 ` dmalcolm at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2020-08-18 0:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94447
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|UNCONFIRMED |RESOLVED
--- Comment #4 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
I implemented gassign from CONSTRUCTOR in
r11-2694-g808f4dfeb3a95f50f15e71148e5c1067f90a126d, including a test case for
the example in comment #0. Marking this one as resolved.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-04-01 16:10 [Bug analyzer/94447] New: Not handling CONSTRUCTOR tree code dmalcolm at gcc dot gnu.org
2020-04-28 13:26 ` [Bug analyzer/94447] " cvs-commit at gcc dot gnu.org
2020-04-28 13:36 ` dmalcolm at gcc dot gnu.org
2020-05-08 13:14 ` dmalcolm at gcc dot gnu.org
2020-08-18 0:59 ` dmalcolm at gcc dot gnu.org
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