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author | David Malcolm <dmalcolm@redhat.com> | 2022-04-14 09:52:00 -0400 |
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committer | David Malcolm <dmalcolm@redhat.com> | 2022-04-14 18:42:34 -0400 |
commit | a358e4b60815b41e27f3508014ceb592f86b9b45 (patch) | |
tree | cd2325b0d8fb044595e2689284b3d83fc38b4d7b /gcc/analyzer/svalue.h | |
parent | af27d545dc6132dcd67d1ee854372ea9cfd2a225 (diff) | |
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analyzer: fix escaping of pointer arithmetic [PR105264]
PR analyzer/105264 reports that the analyzer can fail to treat
(PTR + IDX) and PTR[IDX] as referring to the same memory under
some situations.
There are various ways in which this can happen when IDX is a
symbolic value, due to having several ways in which such memory
regions can be referred to symbolically. I attempted to fix this by
being smarter when folding svalues and regions, but this fix
seems too fiddly to attempt in stage 4.
Instead, this less ambitious patch fixes a false positive from
-Wanalyzer-use-of-uninitialized-value by making the analyzer's escape
analysis smarter, so that it treats *PTR as escaping when
(PTR + OFFSET) is passed to an external function, and thus
it treats *PTR as possibly-initialized (the "passing &PTR[IDX]" case
was already working).
gcc/analyzer/ChangeLog:
PR analyzer/105264
* region-model-reachability.cc (reachable_regions::handle_parm):
Use maybe_get_deref_base_region rather than just region_svalue, to
handle pointer arithmetic also.
* svalue.cc (svalue::maybe_get_deref_base_region): New.
* svalue.h (svalue::maybe_get_deref_base_region): New decl.
gcc/testsuite/ChangeLog:
PR analyzer/105264
* gcc.dg/analyzer/torture/symbolic-10.c: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
Diffstat (limited to 'gcc/analyzer/svalue.h')
-rw-r--r-- | gcc/analyzer/svalue.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/gcc/analyzer/svalue.h b/gcc/analyzer/svalue.h index 4bbe858..29ea2ee 100644 --- a/gcc/analyzer/svalue.h +++ b/gcc/analyzer/svalue.h @@ -175,6 +175,8 @@ public: per-type and thus it's meaningless for them to "have state". */ virtual bool can_have_associated_state_p () const { return true; } + const region *maybe_get_deref_base_region () const; + protected: svalue (complexity c, tree type) : m_complexity (c), m_type (type) |