cgraph: add selftest::symbol_table_test

This patch adds a selftest fixture for overriding the "symtab" global,
so that selftests involving symtab nodes can be isolated from each
other: each selftest can have its own symbol_table instance.

In particular, this ensures that nodes can have a predictable "order"
and thus predictable dump names within selftests.

gcc/ChangeLog:
	* cgraph.c: Include "selftest.h".
	(saved_symtab): New variable.
	(selftest::symbol_table_test::symbol_table_test): New ctor.
	(selftest::symbol_table_test::~symbol_table_test): New dtor.
	(selftest::test_symbol_table_test): New test.
	(selftest::cgraph_c_tests): New.
	* cgraph.h (saved_symtab): New decl.
	(selftest::symbol_table_test): New class.
	* selftest-run-tests.c (selftest::run_tests): Call
	selftest::cgraph_c_tests.
	* selftest.h (selftest::cgraph_c_tests): New decl.

From-SVN: r265915

1 files changed, 23 insertions, 0 deletions

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index c13d798..0215522 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -3353,4 +3353,27 @@ xstrdup_for_dump (const char *transient_str)
   return ggc_strdup (transient_str);
 }
 
+extern GTY(()) symbol_table *saved_symtab;
+
+#if CHECKING_P
+
+namespace selftest {
+
+/* An RAII-style class for use in selftests for temporarily using a different
+   symbol_table, so that such tests can be isolated from each other.  */
+
+class symbol_table_test
+{
+ public:
+  /* Constructor.  Override "symtab".  */
+  symbol_table_test ();
+
+  /* Destructor.  Restore the saved_symtab.  */
+  ~symbol_table_test ();
+};
+
+} // namespace selftest
+
+#endif /* CHECKING_P */
+
 #endif  /* GCC_CGRAPH_H  */