new file mode 100644
@@ -0,0 +1,149 @@
+/* A state machine for use in DejaGnu tests, to check that
+ pattern-matching works as expected.
+
+ Copyright (C) 2019-2020 Free Software Foundation, Inc.
+ Contributed by David Malcolm <dmalcolm@redhat.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "function.h"
+#include "basic-block.h"
+#include "gimple.h"
+#include "tree-pretty-print.h"
+#include "diagnostic-path.h"
+#include "diagnostic-metadata.h"
+#include "analyzer/analyzer.h"
+#include "analyzer/pending-diagnostic.h"
+#include "analyzer/sm.h"
+
+#if ENABLE_ANALYZER
+
+namespace {
+
+/* A state machine for use in DejaGnu tests, to check that
+ pattern-matching works as expected. */
+
+class pattern_test_state_machine : public state_machine
+{
+public:
+ pattern_test_state_machine (logger *logger);
+
+ bool inherited_state_p () const FINAL OVERRIDE { return false; }
+
+ bool on_stmt (sm_context *sm_ctxt,
+ const supernode *node,
+ const gimple *stmt) const FINAL OVERRIDE;
+
+ void on_condition (sm_context *sm_ctxt,
+ const supernode *node,
+ const gimple *stmt,
+ tree lhs,
+ enum tree_code op,
+ tree rhs) const FINAL OVERRIDE;
+
+ bool can_purge_p (state_t s) const FINAL OVERRIDE;
+
+private:
+ state_t m_start;
+};
+
+class pattern_match : public pending_diagnostic_subclass<pattern_match>
+{
+public:
+ pattern_match (tree lhs, enum tree_code op, tree rhs)
+ : m_lhs (lhs), m_op (op), m_rhs (rhs) {}
+
+ const char *get_kind () const FINAL OVERRIDE { return "pattern_match"; }
+
+ bool operator== (const pattern_match &other) const
+ {
+ return (m_lhs == other.m_lhs
+ && m_op == other.m_op
+ && m_rhs == other.m_rhs);
+ }
+
+ bool emit (rich_location *rich_loc) FINAL OVERRIDE
+ {
+ return warning_at (rich_loc, 0, "pattern match on %<%E %s %E%>",
+ m_lhs, op_symbol_code (m_op), m_rhs);
+ }
+
+private:
+ tree m_lhs;
+ enum tree_code m_op;
+ tree m_rhs;
+};
+
+pattern_test_state_machine::pattern_test_state_machine (logger *logger)
+: state_machine ("pattern-test", logger)
+{
+ m_start = add_state ("start");
+}
+
+bool
+pattern_test_state_machine::on_stmt (sm_context *sm_ctxt ATTRIBUTE_UNUSED,
+ const supernode *node ATTRIBUTE_UNUSED,
+ const gimple *stmt ATTRIBUTE_UNUSED) const
+{
+ return false;
+}
+
+/* Implementation of state_machine::on_condition vfunc for
+ pattern_test_state_machine.
+
+ Queue a pattern_match diagnostic for any comparison against a
+ constant. */
+
+void
+pattern_test_state_machine::on_condition (sm_context *sm_ctxt,
+ const supernode *node,
+ const gimple *stmt,
+ tree lhs,
+ enum tree_code op,
+ tree rhs) const
+{
+ if (stmt == NULL)
+ return;
+
+ if (!CONSTANT_CLASS_P (rhs))
+ return;
+
+ pending_diagnostic *diag = new pattern_match (lhs, op, rhs);
+ sm_ctxt->warn_for_state (node, stmt, lhs, m_start, diag);
+}
+
+bool
+pattern_test_state_machine::can_purge_p (state_t s ATTRIBUTE_UNUSED) const
+{
+ return true;
+}
+
+} // anonymous namespace
+
+/* Internal interface to this file. */
+
+state_machine *
+make_pattern_test_state_machine (logger *logger)
+{
+ return new pattern_test_state_machine (logger);
+}
+
+#endif /* #if ENABLE_ANALYZER */
Jeff approved the v1 version of this patch here: https://gcc.gnu.org/ml/gcc-patches/2019-12/msg00508.html and the subsequent changes are obvious in my view. Changed in v5: - update ChangeLog path - updated copyright years to include 2020 Changed in v4: - Remove include of gcc-plugin.h, reworking includes accordingly. - Wrap everything in #if ENABLE_ANALYZER - Remove /// comment lines - Rework on_leak vfunc: https://gcc.gnu.org/ml/gcc-patches/2019-11/msg02028.html This patch adds a custom state machine checker intended purely for DejaGnu testing of the sm "machinery". gcc/analyzer/ChangeLog: * sm-pattern-test.cc: New file. --- gcc/analyzer/sm-pattern-test.cc | 149 ++++++++++++++++++++++++++++++++ 1 file changed, 149 insertions(+) create mode 100644 gcc/analyzer/sm-pattern-test.cc