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

gcc/ChangeLog

 2016-08-08  David Malcolm  <dmalcolm@redhat.com>
 
+	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.
+
+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
 	PR bootstrap/72844
 	* input.c: Ensure that HAVE_ICONV is defined.
 

gcc/c-family/ChangeLog

 2016-08-08  David Malcolm  <dmalcolm@redhat.com>
 
+	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.
+
+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
 	PR c/52952
 	* c-format.c: Include "diagnostic.h".
 	(location_column_from_byte_offset): Delete.

gcc/c-family/c-common.h

@@ -1533,4 +1533,11 @@ extern bool valid_array_size_p (location_t, tree, tree);
 extern bool cilk_ignorable_spawn_rhs_op (tree);
 extern bool cilk_recognize_spawn (tree, tree *);
 
+#if CHECKING_P
+namespace selftest {
+  extern void c_format_c_tests (void);
+  extern void run_c_tests (void);
+} // namespace selftest
+#endif /* #if CHECKING_P */
+
 #endif /* ! GCC_C_COMMON_H */

gcc/c/ChangeLog

+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
+	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.
+
 2016-08-04  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* c-parser.c (struct oacc_routine_data): Add error_seen and

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"

gcc/langhooks-def.h

@@ -120,6 +120,7 @@ extern bool lhd_omp_mappable_type (tree);
 #define LANG_HOOKS_BLOCK_MAY_FALLTHRU	hook_bool_const_tree_true
 #define LANG_HOOKS_EH_USE_CXA_END_CLEANUP	false
 #define LANG_HOOKS_DEEP_UNSHARING	false
+#define LANG_HOOKS_RUN_LANG_SELFTESTS   lhd_do_nothing
 
 /* Attribute hooks.  */
 #define LANG_HOOKS_ATTRIBUTE_TABLE		NULL
@@ -319,7 +320,8 @@ extern void lhd_end_section (void);
   LANG_HOOKS_EH_PROTECT_CLEANUP_ACTIONS, \
   LANG_HOOKS_BLOCK_MAY_FALLTHRU, \
   LANG_HOOKS_EH_USE_CXA_END_CLEANUP, \
-  LANG_HOOKS_DEEP_UNSHARING \
+  LANG_HOOKS_DEEP_UNSHARING, \
+  LANG_HOOKS_RUN_LANG_SELFTESTS \
 }
 
 #endif /* GCC_LANG_HOOKS_DEF_H */

gcc/langhooks.h

@@ -505,6 +505,9 @@ struct lang_hooks
      gimplification.  */
   bool deep_unsharing;
 
+  /* Run all lang-specific selftests.  */
+  void (*run_lang_selftests) (void);
+
   /* Whenever you add entries here, make sure you adjust langhooks-def.h
      and langhooks.c accordingly.  */
 };

gcc/selftest-run-tests.c

@@ -21,6 +21,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "system.h"
 #include "coretypes.h"
 #include "selftest.h"
+#include "tree.h"
+#include "langhooks.h"
 
 /* This function needed to be split out from selftest.c as it references
    tests from the whole source tree, and so is within
@@ -70,6 +72,9 @@ selftest::run_tests ()
   /* This one relies on most of the above.  */
   function_tests_c_tests ();
 
+  /* Run any lang-specific selftests.  */
+  lang_hooks.run_lang_selftests ();
+
   /* Finished running tests.  */
   long finish_time = get_run_time ();
   long elapsed_time = finish_time - start_time;

gcc/testsuite/ChangeLog

+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c/64955
+	* gcc.dg/format/diagnostic-ranges.c: Add fix-it hints to expected
+	output.
+
 2016-08-08  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
 
 	* gcc.dg/tree-ssa/pr71078-1.c: Add require-effective-target

gcc/testsuite/gcc.dg/format/diagnostic-ranges.c

@@ -12,6 +12,25 @@ void test_mismatching_types (const char *msg)
 /* { dg-begin-multiline-output "" }
    printf("hello %i", msg);
                  ~^
+                 %s
+   { dg-end-multiline-output "" } */
+
+
+  printf("hello %s", 42);  /* { dg-warning "format '%s' expects argument of type 'char \\*', but argument 2 has type 'int'" } */
+/* TODO: ideally would also underline "42".  */
+/* { dg-begin-multiline-output "" }
+   printf("hello %s", 42);
+                 ~^
+                 %d
+   { dg-end-multiline-output "" } */
+
+
+  printf("hello %i", (long)0);  /* { dg-warning "format '%i' expects argument of type 'int', but argument 2 has type 'long int' " } */
+/* TODO: ideally would also underline the argument.  */
+/* { dg-begin-multiline-output "" }
+   printf("hello %i", (long)0);
+                 ~^
+                 %ld
    { dg-end-multiline-output "" } */
 }
 
@@ -23,6 +42,7 @@ void test_multiple_arguments (void)
 /* { dg-begin-multiline-output "" }
    printf ("arg0: %i  arg1: %s arg 2: %i",
                             ~^
+                            %d
    { dg-end-multiline-output "" } */
 }
 
@@ -33,6 +53,7 @@ void test_multiple_arguments_2 (int i, int j)
 /* { dg-begin-multiline-output "" }
    printf ("arg0: %i  arg1: %s arg 2: %i",
                             ~^
+                            %d
            100, i + j, 102);
                 ~~~~~         
    { dg-end-multiline-output "" } */
@@ -67,6 +88,7 @@ void test_hex (const char *msg)
 /* { dg-begin-multiline-output "" }
    printf("hello \x25\x69", msg);
                  ~~~~~~~^
+                 %s
    { dg-end-multiline-output "" } */
 }
 
@@ -80,6 +102,7 @@ void test_oct (const char *msg)
 /* { dg-begin-multiline-output "" }
    printf("hello \045\151", msg);
                  ~~~~~~~^
+                 %s
    { dg-end-multiline-output "" } */
 }
 
@@ -98,6 +121,7 @@ void test_multiple (const char *msg)
 /* { dg-begin-multiline-output "" }
    printf("prefix"  "\x25"  "\151"  "suffix",
                      ~~~~~~~~~~~^
+                     %s
   { dg-end-multiline-output "" } */
 }
 
@@ -108,6 +132,7 @@ void test_u8 (const char *msg)
 /* { dg-begin-multiline-output "" }
    printf(u8"hello %i", msg);
                    ~^
+                   %s
    { dg-end-multiline-output "" } */
 }
 
@@ -117,6 +142,7 @@ void test_param (long long_i, long long_j)
 /* { dg-begin-multiline-output "" }
    printf ("foo %s bar", long_i + long_j);
                 ~^       ~~~~~~~~~~~~~~~
+                %ld
    { dg-end-multiline-output "" } */
 }
 
@@ -192,13 +218,14 @@ void test_macro (const char *msg)
 /* { dg-begin-multiline-output "" }
  #define INT_FMT "%i"
                   ~^
+                  %s
    { dg-end-multiline-output "" } */
 }
 
 void test_non_contiguous_strings (void)
 {
   __builtin_printf(" %" "d ", 0.5); /* { dg-warning "20: format .%d. expects argument of type .int., but argument 2 has type .double." } */
-                                    /* { dg-message "26: format string is defined here" "" { target *-*-* } 200 } */
+                                    /* { dg-message "26: format string is defined here" "" { target *-*-* } 227 } */
   /* { dg-begin-multiline-output "" }
    __builtin_printf(" %" "d ", 0.5);
                     ^~~~
@@ -206,6 +233,7 @@ void test_non_contiguous_strings (void)
   /* { dg-begin-multiline-output "" }
    __builtin_printf(" %" "d ", 0.5);
                       ~~~~^
+                      %f
    { dg-end-multiline-output "" } */
 }