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* [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration
@ 2020-04-22 13:21 vincent-gcc at vinc17 dot net
2020-04-23 5:12 ` [Bug analyzer/94714] " marxin at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: vincent-gcc at vinc17 dot net @ 2020-04-22 13:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
Bug ID: 94714
Summary: Analyzer: no warning on access of an uninitialized
variable of automatic storage duration
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: vincent-gcc at vinc17 dot net
Target Milestone: ---
Test with: gcc-10 (Debian 10-20200418-1) 10.0.1 20200418 (experimental) [master
revision 27c171775ab:4c277008be0:c5bac7d127f288fd2f8a1f15c3f30da5903141c6]
Consider:
#include <stdio.h>
int main (void)
{
int *p;
int i;
p = &i;
printf ("%d\n", p[0]);
return 0;
}
With "gcc-10 tst.c -o tst -O3 -fanalyzer", I do not get any warning from the
analyzer, though p[0] is uninitialized. Ditto without optimizations (in which
case, running the program really shows that i is uninitialized).
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug analyzer/94714] Analyzer: no warning on access of an uninitialized variable of automatic storage duration
2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
@ 2020-04-23 5:12 ` marxin at gcc dot gnu.org
2020-04-28 13:42 ` dmalcolm at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: marxin at gcc dot gnu.org @ 2020-04-23 5:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2020-04-23
Ever confirmed|0 |1
CC| |marxin at gcc dot gnu.org
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug analyzer/94714] Analyzer: no warning on access of an uninitialized variable of automatic storage duration
2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
2020-04-23 5:12 ` [Bug analyzer/94714] " marxin at gcc dot gnu.org
@ 2020-04-28 13:42 ` dmalcolm at gcc dot gnu.org
2021-04-27 11:38 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2020-04-28 13:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |11.0
--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks for filing this bug.
I've removed -Wanalyzer-use-of-uninitialized-value for GCC 10 (in
r10-8012-g78b9783774bfd3540f38f5b1e3c7fc9f719653d7) since the underlying
region_model code is too buggy to support it. I'm rewriting it for GCC 11 and
hope to reintroduce the warning there; setting target milestone accordingly.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug analyzer/94714] Analyzer: no warning on access of an uninitialized variable of automatic storage duration
2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
2020-04-23 5:12 ` [Bug analyzer/94714] " marxin at gcc dot gnu.org
2020-04-28 13:42 ` dmalcolm at gcc dot gnu.org
@ 2021-04-27 11:38 ` jakub at gcc dot gnu.org
2021-07-15 19:09 ` cvs-commit at gcc dot gnu.org
2021-07-15 19:35 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-04-27 11:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|11.0 |11.2
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.1 has been released, retargeting bugs to GCC 11.2.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug analyzer/94714] Analyzer: no warning on access of an uninitialized variable of automatic storage duration
2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
` (2 preceding siblings ...)
2021-04-27 11:38 ` jakub at gcc dot gnu.org
@ 2021-07-15 19:09 ` cvs-commit at gcc dot gnu.org
2021-07-15 19:35 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-07-15 19:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
--- Comment #3 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:33255ad3ac14e3953750fe0f2d82b901c2852ff6
commit r12-2337-g33255ad3ac14e3953750fe0f2d82b901c2852ff6
Author: David Malcolm <dmalcolm@redhat.com>
Date: Thu Jul 15 15:07:07 2021 -0400
analyzer: reimplement -Wanalyzer-use-of-uninitialized-value [PR95006 et al]
The initial gcc 10 era commit of the analyzer (in
757bf1dff5e8cee34c0a75d06140ca972bfecfa7) had an implementation of
-Wanalyzer-use-of-uninitialized-value, but was sufficiently buggy
that I removed it in 78b9783774bfd3540f38f5b1e3c7fc9f719653d7 before
the release of gcc 10.1
This patch reintroduces the warning, heavily rewritten, with (I hope)
a less buggy implementation this time, for GCC 12.
gcc/analyzer/ChangeLog:
PR analyzer/95006
PR analyzer/94713
PR analyzer/94714
* analyzer.cc (maybe_reconstruct_from_def_stmt): Split out
GIMPLE_ASSIGN case into...
(get_diagnostic_tree_for_gassign_1): New.
(get_diagnostic_tree_for_gassign): New.
* analyzer.h (get_diagnostic_tree_for_gassign): New decl.
* analyzer.opt (Wanalyzer-write-to-string-literal): New.
* constraint-manager.cc (class svalue_purger): New.
(constraint_manager::purge_state_involving): New.
* constraint-manager.h
(constraint_manager::purge_state_involving): New.
* diagnostic-manager.cc (saved_diagnostic::supercedes_p): New.
(dedupe_winners::handle_interactions): New.
(diagnostic_manager::emit_saved_diagnostics): Call it.
* diagnostic-manager.h (saved_diagnostic::supercedes_p): New decl.
* engine.cc (impl_region_model_context::warn): Convert return type
to bool. Return false if the diagnostic isn't saved.
(impl_region_model_context::purge_state_involving): New.
(impl_sm_context::get_state): Use NULL ctxt when querying old
rvalue.
(impl_sm_context::set_next_state): Use new sval when querying old
state.
(class dump_path_diagnostic): Move to region-model.cc
(exploded_node::on_stmt): Move to on_stmt_pre and on_stmt_post.
Remove call to purge_state_involving.
(exploded_node::on_stmt_pre): New, based on the above. Move most
of it to region_model::on_stmt_pre.
(exploded_node::on_stmt_post): Likewise, moving to
region_model::on_stmt_post.
(class stale_jmp_buf): Fix parent class to use curiously recurring
template pattern.
(feasibility_state::maybe_update_for_edge): Call on_call_pre and
on_call_post on gcalls.
* exploded-graph.h (impl_region_model_context::warn): Return bool.
(impl_region_model_context::purge_state_involving): New decl.
(exploded_node::on_stmt_pre): New decl.
(exploded_node::on_stmt_post): New decl.
* pending-diagnostic.h (pending_diagnostic::use_of_uninit_p): New.
(pending_diagnostic::supercedes_p): New.
* program-state.cc (sm_state_map::get_state): Inherit state for
conjured_svalue as well as initial_svalue.
(sm_state_map::purge_state_involving): Also support SK_CONJURED.
* region-model-impl-calls.cc (call_details::get_uncertainty):
Handle m_ctxt being NULL.
(call_details::get_or_create_conjured_svalue): New.
(region_model::impl_call_fgets): New.
(region_model::impl_call_fread): New.
* region-model-manager.cc
(region_model_manager::get_or_create_initial_value): Return an
uninitialized poisoned value for regions that can't have initial
values.
* region-model-reachability.cc
(reachable_regions::mark_escaped_clusters): Handle ctxt being
NULL.
* region-model.cc (region_to_value_map::purge_state_involving):
New.
(poisoned_value_diagnostic::use_of_uninit_p): New.
(poisoned_value_diagnostic::emit): Handle POISON_KIND_UNINIT.
(poisoned_value_diagnostic::describe_final_event): Likewise.
(region_model::check_for_poison): New.
(region_model::on_assignment): Call it.
(class dump_path_diagnostic): Move here from engine.cc.
(region_model::on_stmt_pre): New, based on exploded_node::on_stmt.
(region_model::on_call_pre): Move the setting of the LHS to a
conjured svalue to before the checks for specific functions.
Handle "fgets", "fgets_unlocked", and "fread".
(region_model::purge_state_involving): New.
(region_model::handle_unrecognized_call): Handle ctxt being NULL.
(region_model::get_rvalue): Call check_for_poison.
(selftest::test_stack_frames): Use NULL for context when getting
uninitialized rvalue.
(selftest::test_alloca): Likewise.
* region-model.h (region_to_value_map::purge_state_involving): New
decl.
(call_details::get_or_create_conjured_svalue): New decl.
(region_model::on_stmt_pre): New decl.
(region_model::purge_state_involving): New decl.
(region_model::impl_call_fgets): New decl.
(region_model::impl_call_fread): New decl.
(region_model::check_for_poison): New decl.
(region_model_context::warn): Return bool.
(region_model_context::purge_state_involving): New.
(noop_region_model_context::warn): Return bool.
(noop_region_model_context::purge_state_involving): New.
(test_region_model_context:: warn): Return bool.
* region.cc (region::get_memory_space): New.
(region::can_have_initial_svalue_p): New.
(region::involves_p): New.
* region.h (enum memory_space): New.
(region::get_memory_space): New decl.
(region::can_have_initial_svalue_p): New decl.
(region::involves_p): New decl.
* sm-malloc.cc (use_after_free::supercedes_p): New.
* store.cc (binding_cluster::purge_state_involving): New.
(store::purge_state_involving): New.
* store.h (class symbolic_binding): New forward decl.
(binding_key::dyn_cast_symbolic_binding): New.
(symbolic_binding::dyn_cast_symbolic_binding): New.
(binding_cluster::purge_state_involving): New.
(store::purge_state_involving): New.
* svalue.cc (svalue::can_merge_p): Reject attempts to merge
poisoned svalues with other svalues, so that we identify
paths in which a variable is conditionally uninitialized.
(involvement_visitor::visit_conjured_svalue): New.
(svalue::involves_p): Also handle SK_CONJURED.
(poison_kind_to_str): Handle POISON_KIND_UNINIT.
(poisoned_svalue::maybe_fold_bits_within): New.
* svalue.h (enum poison_kind): Add POISON_KIND_UNINIT.
(poisoned_svalue::maybe_fold_bits_within): New decl.
gcc/ChangeLog:
PR analyzer/95006
PR analyzer/94713
PR analyzer/94714
* doc/invoke.texi: Add -Wanalyzer-use-of-uninitialized-value.
gcc/testsuite/ChangeLog:
PR analyzer/95006
PR analyzer/94713
PR analyzer/94714
* g++.dg/analyzer/pr93212.C: Update location of warning.
* g++.dg/analyzer/pr94011.C: Add
-Wno-analyzer-use-of-uninitialized-value.
* g++.dg/analyzer/pr94503.C: Likewise.
* gcc.dg/analyzer/clobbers-1.c: Convert "f" from a local to a
param to avoid uninitialized warning.
* gcc.dg/analyzer/data-model-1.c (test_12): Add test for
uninitialized value on result of alloca.
(test_12a): Add expected warning.
(test_12c): Likewise.
(test_19): Likewise.
(test_29b): Likewise.
(test_29c): Likewise.
(test_37): Remove xfail.
(test_37a): Likewise.
* gcc.dg/analyzer/data-model-20.c: Add warning about leak.
* gcc.dg/analyzer/explode-2.c: Remove params; add
-Wno-analyzer-too-complex, -Wno-analyzer-malloc-leak, and xfails.
Initialize the locals.
* gcc.dg/analyzer/explode-2a.c: Initialize the locals. Add
expected leak.
* gcc.dg/analyzer/fgets-1.c: New test.
* gcc.dg/analyzer/fread-1.c: New test.
* gcc.dg/analyzer/malloc-1.c (test_16): Add expected warning.
(test_40): Likewise.
* gcc.dg/analyzer/memset-CVE-2017-18549-1.c: Check for
uninitialized padding.
* gcc.dg/analyzer/pr93355-localealias-feasibility.c (fread): New
decl.
(read_alias_file): Call it.
* gcc.dg/analyzer/pr94047.c: Add expected warnings.
* gcc.dg/analyzer/pr94851-2.c: Likewise.
* gcc.dg/analyzer/pr96841.c: Convert local to a param.
* gcc.dg/analyzer/pr98628.c: Likewise.
* gcc.dg/analyzer/pr99042.c: Updated expected location of leak
diagnostics.
* gcc.dg/analyzer/symbolic-1.c: Add expected warnings.
* gcc.dg/analyzer/symbolic-7.c: Likewise.
* gcc.dg/analyzer/torture/pr93649.c: Add expected warning. Skip
with -fno-fat-lto-objects.
* gcc.dg/analyzer/uninit-1.c: New test.
* gcc.dg/analyzer/uninit-2.c: New test.
* gcc.dg/analyzer/uninit-3.c: New test.
* gcc.dg/analyzer/uninit-4.c: New test.
* gcc.dg/analyzer/uninit-pr94713.c: New test.
* gcc.dg/analyzer/uninit-pr94714.c: New test.
* gcc.dg/analyzer/use-after-free-2.c: New test.
* gcc.dg/analyzer/use-after-free-3.c: New test.
* gcc.dg/analyzer/zlib-3.c: Add expected warning.
* gcc.dg/analyzer/zlib-6.c: Convert locals to params to avoid
uninitialized warnings. Remove xfail.
* gcc.dg/analyzer/zlib-6a.c: New test, based on the old version
of the above.
* gfortran.dg/analyzer/pr97668.f: Add
-Wno-analyzer-use-of-uninitialized-value and
-Wno-analyzer-too-complex.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug analyzer/94714] Analyzer: no warning on access of an uninitialized variable of automatic storage duration
2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
` (3 preceding siblings ...)
2021-07-15 19:09 ` cvs-commit at gcc dot gnu.org
@ 2021-07-15 19:35 ` dmalcolm at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: dmalcolm at gcc dot gnu.org @ 2021-07-15 19:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94714
David Malcolm <dmalcolm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Should be fixed on trunk for gcc 12 by the above patch.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2020-04-22 13:21 [Bug analyzer/94714] New: Analyzer: no warning on access of an uninitialized variable of automatic storage duration vincent-gcc at vinc17 dot net
2020-04-23 5:12 ` [Bug analyzer/94714] " marxin at gcc dot gnu.org
2020-04-28 13:42 ` dmalcolm at gcc dot gnu.org
2021-04-27 11:38 ` jakub at gcc dot gnu.org
2021-07-15 19:09 ` cvs-commit at gcc dot gnu.org
2021-07-15 19:35 ` dmalcolm at gcc dot gnu.org
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