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author | David Malcolm <dmalcolm@redhat.com> | 2023-02-09 17:09:51 -0500 |
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committer | David Malcolm <dmalcolm@redhat.com> | 2023-02-09 17:09:51 -0500 |
commit | 125b57aa67400388a496c2c0c40d9c8c55e0c94a (patch) | |
tree | dfc35cfe81c72d775fcc456d2f37bf9495627eb0 /gcc/analyzer | |
parent | 10827a92f1a8c3207b327515f77845b34c1d9512 (diff) | |
download | gcc-125b57aa67400388a496c2c0c40d9c8c55e0c94a.zip gcc-125b57aa67400388a496c2c0c40d9c8c55e0c94a.tar.gz gcc-125b57aa67400388a496c2c0c40d9c8c55e0c94a.tar.bz2 |
analyzer: fix further overzealous state purging [PR108733]
PR analyzer/108733 reports various false positives in qemu from
-Wanalyzer-use-of-uninitialized-value with __attribute__((cleanup))
at -O1 and above.
Root cause is that the state-purging code was failing to treat:
_25 = MEM[(void * *)&val];
as a usage of "val", leading to it erroneously purging the
initialization of "val" along an execution path that didn't otherwise
use "val", apart from the __attribute__((cleanup)).
Fixed thusly.
Integration testing on the patch show this change in the number of
diagnostics:
-Wanalyzer-use-of-uninitialized-value
coreutils-9.1: 18 -> 16 (-2)
qemu-7.2.0: 87 -> 80 (-7)
where all that I investigated appear to have been false positives, hence
an improvement.
gcc/analyzer/ChangeLog:
PR analyzer/108733
* state-purge.cc (get_candidate_for_purging): Add ADDR_EXPR
and MEM_REF.
gcc/testsuite/ChangeLog:
PR analyzer/108733
* gcc.dg/analyzer/torture/uninit-pr108733.c: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
Diffstat (limited to 'gcc/analyzer')
-rw-r--r-- | gcc/analyzer/state-purge.cc | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/gcc/analyzer/state-purge.cc b/gcc/analyzer/state-purge.cc index 5f2d1f7..3a73146 100644 --- a/gcc/analyzer/state-purge.cc +++ b/gcc/analyzer/state-purge.cc @@ -63,6 +63,8 @@ get_candidate_for_purging (tree node) default: return NULL_TREE; + case ADDR_EXPR: + case MEM_REF: case COMPONENT_REF: iter = TREE_OPERAND (iter, 0); continue; |