From ac3966e315ada63eb379d560a012fa77c3909155 Mon Sep 17 00:00:00 2001 From: David Malcolm Date: Tue, 5 Jan 2021 20:54:50 -0500 Subject: [PATCH] analyzer: fix false leaks when writing through unknown ptrs [PR97072] gcc/analyzer/ChangeLog: PR analyzer/97072 * region-model-reachability.cc (reachable_regions::init_cluster): Convert symbolic region handling to a switch statement. Add cases to handle SK_UNKNOWN and SK_CONJURED. gcc/testsuite/ChangeLog: PR analyzer/97072 * gcc.dg/analyzer/pr97072.c: New test. --- gcc/analyzer/region-model-reachability.cc | 36 +++++++++++++++++------ gcc/testsuite/gcc.dg/analyzer/pr97072.c | 9 ++++++ 2 files changed, 36 insertions(+), 9 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/analyzer/pr97072.c diff --git a/gcc/analyzer/region-model-reachability.cc b/gcc/analyzer/region-model-reachability.cc index daf785254ea..a988ffc1439 100644 --- a/gcc/analyzer/region-model-reachability.cc +++ b/gcc/analyzer/region-model-reachability.cc @@ -88,20 +88,38 @@ reachable_regions::init_cluster (const region *base_reg) if (m_store->escaped_p (base_reg)) add (base_reg, true); - /* If BASE_REG is *INIT_VAL(REG) for some other REG, see if REG is - unbound and untouched. If so, then add BASE_REG as a root. */ if (const symbolic_region *sym_reg = base_reg->dyn_cast_symbolic_region ()) { const svalue *ptr = sym_reg->get_pointer (); - if (const initial_svalue *init_sval = ptr->dyn_cast_initial_svalue ()) + switch (ptr->get_kind ()) { - const region *init_sval_reg = init_sval->get_region (); - const region *other_base_reg = init_sval_reg->get_base_region (); - const binding_cluster *other_cluster - = m_store->get_cluster (other_base_reg); - if (other_cluster == NULL - || !other_cluster->touched_p ()) + default: + break; + case SK_INITIAL: + { + /* If BASE_REG is *INIT_VAL(REG) for some other REG, see if REG is + unbound and untouched. If so, then add BASE_REG as a root. */ + const initial_svalue *init_sval + = as_a (ptr); + const region *init_sval_reg = init_sval->get_region (); + const region *other_base_reg = init_sval_reg->get_base_region (); + const binding_cluster *other_cluster + = m_store->get_cluster (other_base_reg); + if (other_cluster == NULL + || !other_cluster->touched_p ()) + add (base_reg, true); + } + break; + + case SK_UNKNOWN: + case SK_CONJURED: + { + /* If this cluster is due to dereferencing an unknown/conjured + pointer, any values written through the pointer could still + be live. */ add (base_reg, true); + } + break; } } } diff --git a/gcc/testsuite/gcc.dg/analyzer/pr97072.c b/gcc/testsuite/gcc.dg/analyzer/pr97072.c new file mode 100644 index 00000000000..40241248884 --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/pr97072.c @@ -0,0 +1,9 @@ +void unknown_fn_1 (void *); + +void test_1 (int co, int y) +{ + void *p = __builtin_malloc (1024); + void **q; + unknown_fn_1 (&q); + *q = p; +} -- 2.30.2