Don't suppress bogus usage of macros from system headers in -Wformat (PR c/78304)

gcc/ChangeLog:
	PR c/78304
	* substring-locations.c (format_warning_va): Strengthen case 1 so
	that both endpoints of the substring must be within the format
	range for just the substring to be printed.

gcc/testsuite/ChangeLog:
	PR c/78304
	* gcc.dg/format/diagnostic-ranges.c (test_macro): Undef INT_FMT.
	(test_macro_2): New test.
	(test_macro_3): New test.
	(test_macro_4): New test.
	(test_non_contiguous_strings): Convert line number to line offset.
	* gcc.dg/format/pr78304-2.c: New test case.
	* gcc.dg/format/pr78304.c: New test case.

From-SVN: r244453

gcc/ChangeLog

+2017-01-13  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c/78304
+	* substring-locations.c (format_warning_va): Strengthen case 1 so
+	that both endpoints of the substring must be within the format
+	range for just the substring to be printed.
+
 2017-01-13  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.opt (msgx): Use ix86_isa_flags2 variable.

gcc/substring-locations.c

@@ -118,6 +118,8 @@ format_warning_va (const substring_loc &fmt_loc,
   else
     {
       if (fmt_substring_range.m_start >= fmt_loc_range.m_start
+	  && fmt_substring_range.m_start <= fmt_loc_range.m_finish
+	  && fmt_substring_range.m_finish >= fmt_loc_range.m_start
 	  && fmt_substring_range.m_finish <= fmt_loc_range.m_finish)
 	/* Case 1.  */
 	{

gcc/testsuite/ChangeLog

+2017-01-13  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c/78304
+	* gcc.dg/format/diagnostic-ranges.c (test_macro): Undef INT_FMT.
+	(test_macro_2): New test.
+	(test_macro_3): New test.
+	(test_macro_4): New test.
+	(test_non_contiguous_strings): Convert line number to line offset.
+	* gcc.dg/format/pr78304-2.c: New test case.
+	* gcc.dg/format/pr78304.c: New test case.
+
 2017-01-13  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.target/i386/funcspec-56.inc: Add missing options and

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

@@ -254,12 +254,63 @@ void test_macro (const char *msg)
                   ~^
                   %s
    { dg-end-multiline-output "" } */
+#undef INT_FMT
+}
+
+void test_macro_2 (const char *msg)
+{
+#define PRIu32 "u" /* { dg-message "17: format string is defined here" } */
+  printf("hello %" PRIu32 " world", msg);  /* { dg-warning "10: format '%u' expects argument of type 'unsigned int', but argument 2 has type 'const char \\*' " } */
+/* { dg-begin-multiline-output "" }
+   printf("hello %" PRIu32 " world", msg);
+          ^~~~~~~~~
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+ #define PRIu32 "u"
+                 ^
+   { dg-end-multiline-output "" } */
+#undef PRIu32
+}
+
+void test_macro_3 (const char *msg)
+{
+#define FMT_STRING "hello %i world" /* { dg-warning "20: format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+  printf(FMT_STRING, msg);  /* { dg-message "10: in expansion of macro 'FMT_STRING" } */
+/* { dg-begin-multiline-output "" }
+ #define FMT_STRING "hello %i world"
+                    ^
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+   printf(FMT_STRING, msg);
+          ^~~~~~~~~~
+   { dg-end-multiline-output "" } */
+#undef FMT_STRING
+}
+
+void test_macro_4 (const char *msg)
+{
+#define FMT_STRING "hello %i world" /* { dg-warning "20: format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+  printf(FMT_STRING "\n", msg);  /* { dg-message "10: in expansion of macro 'FMT_STRING" } */
+/* { dg-begin-multiline-output "" }
+ #define FMT_STRING "hello %i world"
+                    ^
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+   printf(FMT_STRING "\n", msg);
+          ^~~~~~~~~~
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+ #define FMT_STRING "hello %i world"
+                           ~^
+                           %s
+   { dg-end-multiline-output "" } */
+#undef FMT_STRING
 }
 
 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 *-*-* } 261 } */
+                                    /* { dg-message "26: format string is defined here" "" { target *-*-* } .-1 } */
   /* { dg-begin-multiline-output "" }
    __builtin_printf(" %" "d ", 0.5);
                     ^~~~

gcc/testsuite/gcc.dg/format/pr78304-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall -Wextra" } */
+
+extern int printf (const char *, ...);
+
+# define PRIu32		"u"
+
+void test (long size)
+{
+  printf ("size: %" PRIu32 "\n", size); /* { dg-warning "expects argument of type" } */
+}

gcc/testsuite/gcc.dg/format/pr78304.c

+/* { dg-do compile { target inttypes_types } } */
+/* { dg-options "-O2 -Wall -Wextra" } */
+
+#include <inttypes.h>
+#include <stdio.h>
+
+void test (size_t size)
+{
+  printf ("size: %" PRIu32 "\n", size); /* { dg-warning "expects argument of type" } */
+}