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| author | David Malcolm <dmalcolm@redhat.com> | 2020-08-27 07:42:27 -0400 |
|---|---|---|
| committer | David Malcolm <dmalcolm@redhat.com> | 2020-09-01 10:56:34 -0400 |
| commit | 49bfbf18c0bb9d83934f0ce765dc031ebfbda38e (patch) | |
| tree | a5ffca38c6d890175030acbc6ce63fd4382097fc /gcc/analyzer | |
| parent | a292e31dac72c20cda3478b866ccf6e07dfad1a4 (diff) | |
| download | gcc-49bfbf18c0bb9d83934f0ce765dc031ebfbda38e.zip gcc-49bfbf18c0bb9d83934f0ce765dc031ebfbda38e.tar.gz gcc-49bfbf18c0bb9d83934f0ce765dc031ebfbda38e.tar.bz2 | |
analyzer: fix false NULL deref warning after previous deref [PR96792]
gcc/analyzer/ChangeLog:
PR analyzer/96792
* region-model.cc (region_model::deref_rvalue): Add the constraint
that PTR_SVAL is non-NULL.
gcc/testsuite/ChangeLog:
PR analyzer/96792
* gcc.dg/analyzer/pr96792.c: New test.
Diffstat (limited to 'gcc/analyzer')
| -rw-r--r-- | gcc/analyzer/region-model.cc | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc index d47e896..a7bc481 100644 --- a/gcc/analyzer/region-model.cc +++ b/gcc/analyzer/region-model.cc @@ -1398,6 +1398,15 @@ region_model::deref_rvalue (const svalue *ptr_sval, tree ptr_tree, { gcc_assert (ptr_sval); + /* If we're dereferencing PTR_SVAL, assume that it is non-NULL; add this + as a constraint. This suppresses false positives from + -Wanalyzer-null-dereference for the case where we later have an + if (PTR_SVAL) that would occur if we considered the false branch + and transitioned the malloc state machine from start->null. */ + tree null_ptr_cst = build_int_cst (ptr_sval->get_type (), 0); + const svalue *null_ptr = m_mgr->get_or_create_constant_svalue (null_ptr_cst); + m_constraints->add_constraint (ptr_sval, NE_EXPR, null_ptr); + switch (ptr_sval->get_kind ()) { default: |