c-format.c: suggest the correct format string to use (PR c/64955)

This adds fix-it hints to c-format.c so that it can (sometimes) suggest
the format string the user should have used.

The patch adds selftests for the new code in c-format.c.  These
selftests are thus lang-specific.  This is the first time we've had
lang-specific selftests, and hence the patch also adds a langhook for
running them.  (Note that currently the Makefile only invokes the
selftests for cc1).

gcc/c-family/ChangeLog:
	PR c/64955
	* c-common.h (selftest::c_format_c_tests): New declaration.
	(selftest::run_c_tests): New declaration.
	* c-format.c: Include "selftest.h.
	(format_warning_va): Add param "corrected_substring" and use
	it to add a replacement fix-it hint.
	(format_warning_at_substring): Likewise.
	(format_warning_at_char): Update for new param of
	format_warning_va.
	(argument_parser::check_argument_type): Pass "fki" to
	check_format_types.
	(check_format_types): Add param "fki" and pass it to
	format_type_warning.
	(deref_n_times): New function.
	(get_modifier_for_format_len): New function.
	(selftest::test_get_modifier_for_format_len): New function.
	(get_format_for_type): New function.
	(format_type_warning): Add param "fki" and use it to attempt
	to provide hints for argument types when calling
	format_warning_at_substring.
	(selftest::get_info): New function.
	(selftest::assert_format_for_type_streq): New function.
	(ASSERT_FORMAT_FOR_TYPE_STREQ): New macro.
	(selftest::test_get_format_for_type_printf): New function.
	(selftest::test_get_format_for_type_scanf): New function.
	(selftest::c_format_c_tests): New function.

gcc/c/ChangeLog:
	PR c/64955
	* c-lang.c (LANG_HOOKS_RUN_LANG_SELFTESTS): If CHECKING_P, wire
	this up to selftest::run_c_tests.
	(selftest::run_c_tests): New function.

gcc/ChangeLog:
	PR c/64955
	* langhooks-def.h (LANG_HOOKS_RUN_LANG_SELFTESTS): New default
	do-nothing langhook.
	(LANG_HOOKS_INITIALIZER): Add LANG_HOOKS_RUN_LANG_SELFTESTS.
	* langhooks.h (struct lang_hooks): Add run_lang_selftests.
	* selftest-run-tests.c: Include "tree.h" and "langhooks.h".
	(selftest::run_tests): Call lang_hooks.run_lang_selftests.

gcc/testsuite/ChangeLog:
	PR c/64955
	* gcc.dg/format/diagnostic-ranges.c: Add fix-it hints to expected
	output.

From-SVN: r239260

1 files changed, 22 insertions, 0 deletions

diff --git a/gcc/c/c-lang.c b/gcc/c/c-lang.c
index 89954b749cf..b26be6ad92c 100644
--- a/gcc/c/c-lang.c
+++ b/gcc/c/c-lang.c
@@ -38,7 +38,29 @@ enum c_language_kind c_language = clk_c;
 #undef LANG_HOOKS_INIT_TS
 #define LANG_HOOKS_INIT_TS c_common_init_ts
 
+#if CHECKING_P
+#undef LANG_HOOKS_RUN_LANG_SELFTESTS
+#define LANG_HOOKS_RUN_LANG_SELFTESTS selftest::run_c_tests
+#endif /* #if CHECKING_P */
+
 /* Each front end provides its own lang hook initializer.  */
 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 
+#if CHECKING_P
+
+namespace selftest {
+
+/* Implementation of LANG_HOOKS_RUN_LANG_SELFTESTS for the C frontend.  */
+
+void
+run_c_tests (void)
+{
+  c_format_c_tests ();
+}
+
+} // namespace selftest
+
+#endif /* #if CHECKING_P */
+
+
 #include "gtype-c.h"