@@ -843,13 +843,21 @@ region_model::check_for_poison (const svalue *sval,
if (const poisoned_svalue *poisoned_sval = sval->dyn_cast_poisoned_svalue ())
{
+ enum poison_kind pkind = poisoned_sval->get_poison_kind ();
+
+ /* Ignore uninitialized uses of empty types; there's nothing
+ to initialize. */
+ if (pkind == POISON_KIND_UNINIT
+ && sval->get_type ()
+ && is_empty_type (sval->get_type ()))
+ return sval;
+
/* If we have an SSA name for a temporary, we don't want to print
'<unknown>'.
Poisoned values are shared by type, and so we can't reconstruct
the tree other than via the def stmts, using
fixup_tree_for_diagnostic. */
tree diag_arg = fixup_tree_for_diagnostic (expr);
- enum poison_kind pkind = poisoned_sval->get_poison_kind ();
const region *src_region = NULL;
if (pkind == POISON_KIND_UNINIT)
src_region = get_region_for_poisoned_expr (expr);
new file mode 100644
@@ -0,0 +1,18 @@
+struct empty {};
+
+struct empty g;
+
+extern void sink (struct empty e);
+
+void test_1 (struct empty a)
+{
+ sink (a); /* { dg-bogus "uninit" } */
+}
+void test_2 ()
+{
+ struct empty a, b;
+ b = a;
+ g = b;
+ sink (b); /* { dg-bogus "uninit" } */
+ /* ...as there's nothing to initialize. */
+}
PR analyzer/104274 reports a false positive from -Wanalyzer-use-of-uninitialized-value on hppa when passing an empty struct as a function parameter. pa_pass_by_reference returns true for empty structs, so the call is turned into: struct empty arg.0; arg.0 = arg called_function (arg.0); by gimplify_parameters. However, gimplify_modify_expr discards assignments statments of empty types, so that we end up with: struct empty arg.0; called_function (arg.0); which the analyzer considers to be a use of uninitialized "arg.0"; Given that gimplify_modify_expr will discard any assignments to such types, it seems simplest for -Wanalyzer-use-of-uninitialized-value to ignore values of empty types. Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu. Pushed to trunk as r12-7199-gcc68ad87014a331399ccb2528db3bf47fabe6f72. gcc/analyzer/ChangeLog: PR analyzer/104274 * region-model.cc (region_model::check_for_poison): Ignore uninitialized uses of empty types. gcc/testsuite/ChangeLog: PR analyzer/104274 * gcc.dg/analyzer/torture/empty-struct-1.c: New test. Signed-off-by: David Malcolm <dmalcolm@redhat.com> --- gcc/analyzer/region-model.cc | 10 +++++++++- .../gcc.dg/analyzer/torture/empty-struct-1.c | 18 ++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/analyzer/torture/empty-struct-1.c