Use class substring_loc in c-format.c (PR c/52952)

gcc/c-family/ChangeLog:
	PR c/52952
	* c-format.c: Include "diagnostic.h".
	(location_column_from_byte_offset): Delete.
	(location_from_offset): Delete.
	(format_warning_va): New function.
	(format_warning_at_substring): New function.
	(format_warning_at_char): New function.
	(check_format_arg): Capture location of format_tree and pass to
	check_format_info_main.
	(argument_parser): Add fields "start_of_this_format" and
	"format_string_cst".
	(flag_chars_t::validate): Add param "format_string_cst".  Convert
	warning_at call using location_from_offset to call to
	format_warning_at_char.
	(argument_parser::argument_parser): Add param "format_string_cst_"
	and use use it to initialize field "format_string_cst".
	Initialize new field "start_of_this_format".
	(argument_parser::read_format_flags): Convert warning_at call
	using location_from_offset to a call to format_warning_at_char.
	(argument_parser::read_any_format_left_precision): Likewise.
	(argument_parser::read_any_format_precision): Likewise.
	(argument_parser::read_any_other_modifier): Likewise.
	(argument_parser::find_format_char_info): Likewise, in three places.
	(argument_parser::parse_any_scan_set): Likewise, in one place.
	(argument_parser::handle_conversions): Likewise, in two places.
	(argument_parser::check_argument_type): Add param "fmt_param_loc"
	and use it to make a substring_loc.  Pass the latter to
	check_format_types.
	(check_format_info_main): Add params "fmt_param_loc" and
	"format_string_cst".  Convert warning_at calls using
	location_from_offset to calls to format_warning_at_char.  Pass the
	new params to the arg_parser ctor.  Pass "format_string_cst" to
	flag_chars.validate.  Pass "fmt_param_loc" to
	arg_parser.check_argument_type.
	(check_format_types): Convert first param from a location_t
	to a const substring_loc & and rename to "fmt_loc".  Attempt
	to extract the range of the relevant parameter and pass it
	to format_type_warning.
	(format_type_warning): Convert first param from a location_t
	to a const substring_loc & and rename to "fmt_loc".  Add
	params "param_range" and "type".  Replace calls to warning_at
	with calls to format_warning_at_substring.

gcc/testsuite/ChangeLog:
	PR c/52952
	* gcc.dg/cpp/pr66415-1.c: Likewise.
	* gcc.dg/format/asm_fprintf-1.c: Update column numbers.
	* gcc.dg/format/c90-printf-1.c: Likewise.
	* gcc.dg/format/diagnostic-ranges.c: New test case.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239253 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 605 insertions, 185 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 4374dbfb1b4..f03a078b438 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,5 +1,50 @@
 2016-08-08  David Malcolm  <dmalcolm@redhat.com>
 
+	PR c/52952
+	* c-format.c: Include "diagnostic.h".
+	(location_column_from_byte_offset): Delete.
+	(location_from_offset): Delete.
+	(format_warning_va): New function.
+	(format_warning_at_substring): New function.
+	(format_warning_at_char): New function.
+	(check_format_arg): Capture location of format_tree and pass to
+	check_format_info_main.
+	(argument_parser): Add fields "start_of_this_format" and
+	"format_string_cst".
+	(flag_chars_t::validate): Add param "format_string_cst".  Convert
+	warning_at call using location_from_offset to call to
+	format_warning_at_char.
+	(argument_parser::argument_parser): Add param "format_string_cst_"
+	and use use it to initialize field "format_string_cst".
+	Initialize new field "start_of_this_format".
+	(argument_parser::read_format_flags): Convert warning_at call
+	using location_from_offset to a call to format_warning_at_char.
+	(argument_parser::read_any_format_left_precision): Likewise.
+	(argument_parser::read_any_format_precision): Likewise.
+	(argument_parser::read_any_other_modifier): Likewise.
+	(argument_parser::find_format_char_info): Likewise, in three places.
+	(argument_parser::parse_any_scan_set): Likewise, in one place.
+	(argument_parser::handle_conversions): Likewise, in two places.
+	(argument_parser::check_argument_type): Add param "fmt_param_loc"
+	and use it to make a substring_loc.  Pass the latter to
+	check_format_types.
+	(check_format_info_main): Add params "fmt_param_loc" and
+	"format_string_cst".  Convert warning_at calls using
+	location_from_offset to calls to format_warning_at_char.  Pass the
+	new params to the arg_parser ctor.  Pass "format_string_cst" to
+	flag_chars.validate.  Pass "fmt_param_loc" to
+	arg_parser.check_argument_type.
+	(check_format_types): Convert first param from a location_t
+	to a const substring_loc & and rename to "fmt_loc".  Attempt
+	to extract the range of the relevant parameter and pass it
+	to format_type_warning.
+	(format_type_warning): Convert first param from a location_t
+	to a const substring_loc & and rename to "fmt_loc".  Add
+	params "param_range" and "type".  Replace calls to warning_at
+	with calls to format_warning_at_substring.
+
+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
 	* c-format.c (class flag_chars_t): New class.
 	(struct length_modifier): New struct.
 	(class argument_parser): New class.
diff --git a/gcc/c-family/c-format.c b/gcc/c-family/c-format.c
index 92d2c1cf5be..eff2ab4321c 100644
--- a/gcc/c-family/c-format.c
+++ b/gcc/c-family/c-format.c
@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "intl.h"
 #include "langhooks.h"
 #include "c-format.h"
+#include "diagnostic.h"
 
 /* Handle attributes associated with format checking.  */
 
@@ -65,78 +66,169 @@ static int first_target_format_type;
 static const char *format_name (int format_num);
 static int format_flags (int format_num);
 
-/* Given a string S of length LINE_WIDTH, find the visual column
-   corresponding to OFFSET bytes.   */
+/* Emit a warning governed by option OPT, using GMSGID as the format
+   string and AP as its arguments.
 
-static unsigned int
-location_column_from_byte_offset (const char *s, int line_width,
-				  unsigned int offset)
-{
-  const char * c = s;
-  if (*c != '"')
-    return 0;
+   Attempt to obtain precise location information within a string
+   literal from FMT_LOC.
+
+   Case 1: if substring location is available, and is within the range of
+   the format string itself, the primary location of the
+   diagnostic is the substring range obtained from FMT_LOC, with the
+   caret at the *end* of the substring range.
+
+   For example:
+
+     test.c:90:10: warning: problem with '%i' here [-Wformat=]
+     printf ("hello %i", msg);
+                    ~^
+
+   Case 2: if the substring location is available, but is not within
+   the range of the format string, the primary location is that of the
+   format string, and an note is emitted showing the substring location.
+
+   For example:
+     test.c:90:10: warning: problem with '%i' here [-Wformat=]
+     printf("hello " INT_FMT " world", msg);
+            ^~~~~~~~~~~~~~~~~~~~~~~~~
+     test.c:19: note: format string is defined here
+     #define INT_FMT "%i"
+                      ~^
+
+   Case 3: if precise substring information is unavailable, the primary
+   location is that of the whole string passed to FMT_LOC's constructor.
+   For example:
+
+     test.c:90:10: warning: problem with '%i' here [-Wformat=]
+     printf(fmt, msg);
+            ^~~
+
+   For each of cases 1-3, if param_range is non-NULL, then it is used
+   as a secondary range within the warning.  For example, here it
+   is used with case 1:
+
+     test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
+     printf ("foo %s bar", long_i + long_j);
+                  ~^       ~~~~~~~~~~~~~~~
 
-  c++, offset--;
-  while (offset > 0)
+   and here with case 2:
+
+     test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
+     printf ("foo " STR_FMT " bar", long_i + long_j);
+             ^~~~~~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~~~~
+     test.c:89:16: note: format string is defined here
+     #define STR_FMT "%s"
+                      ~^
+
+   and with case 3:
+
+     test.c:90:10: warning: '%i' here, but arg 2 is "const char *' [-Wformat=]
+     printf(fmt, msg);
+            ^~~  ~~~
+
+   Return true if a warning was emitted, false otherwise.  */
+
+ATTRIBUTE_GCC_DIAG (4,0)
+static bool
+format_warning_va (const substring_loc &fmt_loc, source_range *param_range,
+		   int opt, const char *gmsgid, va_list *ap)
+{
+  bool substring_within_range = false;
+  location_t primary_loc;
+  location_t substring_loc = UNKNOWN_LOCATION;
+  source_range fmt_loc_range
+    = get_range_from_loc (line_table, fmt_loc.get_fmt_string_loc ());
+  source_range fmt_substring_range;
+  const char *err = fmt_loc.get_range (&fmt_substring_range);
+  if (err)
+    /* Case 3: unable to get substring location.  */
+    primary_loc = fmt_loc.get_fmt_string_loc ();
+  else
     {
-      if (c - s >= line_width)
-	return 0;
+      substring_loc = make_location (fmt_substring_range.m_finish,
+				     fmt_substring_range.m_start,
+				     fmt_substring_range.m_finish);
 
-      switch (*c)
+      if (fmt_substring_range.m_start >= fmt_loc_range.m_start
+	  && fmt_substring_range.m_finish <= fmt_loc_range.m_finish)
+	/* Case 1.  */
 	{
-	case '\\':
-	  c++;
-	  if (c - s >= line_width)
-	    return 0;
-	  switch (*c)
-	    {
-	    case '\\': case '\'': case '"': case '?':
-	    case '(': case '{': case '[': case '%':
-	    case 'a': case 'b': case 'f': case 'n':
-	    case 'r': case 't': case 'v': 
-	    case 'e': case 'E':
-	      c++, offset--;
-	      break;
+	  substring_within_range = true;
+	  primary_loc = substring_loc;
+	}
+      else
+	/* Case 2.  */
+	{
+	  substring_within_range = false;
+	  primary_loc = fmt_loc.get_fmt_string_loc ();
+	}
+    }
 
-	    default:
-	      return 0;
-	    }
-	  break;
+  rich_location richloc (line_table, primary_loc);
 
-	case '"':
-	  /* We found the end of the string too early.  */
-	  return 0;
-	  
-	default:
-	  c++, offset--;
-	  break;
-	}
+  if (param_range)
+    {
+      location_t param_loc = make_location (param_range->m_start,
+					    param_range->m_start,
+					    param_range->m_finish);
+      richloc.add_range (param_loc, false);
     }
-  return c - s;
+
+  diagnostic_info diagnostic;
+  diagnostic_set_info (&diagnostic, gmsgid, ap, &richloc, DK_WARNING);
+  diagnostic.option_index = opt;
+  bool warned = report_diagnostic (&diagnostic);
+
+  if (!err && substring_loc && !substring_within_range)
+    /* Case 2.  */
+    if (warned)
+      inform (substring_loc, "format string is defined here");
+
+  return warned;
 }
 
-/* Return a location that encodes the same location as LOC but shifted
-   by OFFSET bytes.  */
+/* Variadic call to format_warning_va.  */
 
-static location_t
-location_from_offset (location_t loc, int offset)
+ATTRIBUTE_GCC_DIAG (4,0)
+static bool
+format_warning_at_substring (const substring_loc &fmt_loc,
+			     source_range *param_range,
+			     int opt, const char *gmsgid, ...)
 {
-  gcc_checking_assert (offset >= 0);
-  if (linemap_location_from_macro_expansion_p (line_table, loc)
-      || offset < 0)
-    return loc;
+  va_list ap;
+  va_start (ap, gmsgid);
+  bool warned = format_warning_va (fmt_loc, param_range, opt, gmsgid, &ap);
+  va_end (ap);
 
-  expanded_location s = expand_location_to_spelling_point (loc);
-  int line_width;
-  const char *line = location_get_source_line (s.file, s.line, &line_width);
-  if (line == NULL)
-    return loc;
-  line += s.column - 1 ;
-  line_width -= s.column - 1;
-  unsigned int column =
-    location_column_from_byte_offset (line, line_width, (unsigned) offset);
+  return warned;
+}
+
+/* Emit a warning as per format_warning_va, but construct the substring_loc
+   for the character at offset (CHAR_IDX - 1) within a string constant
+   FORMAT_STRING_CST at FMT_STRING_LOC.  */
 
-  return linemap_position_for_loc_and_offset (line_table, loc, column);
+ATTRIBUTE_GCC_DIAG (5,6)
+static bool
+format_warning_at_char (location_t fmt_string_loc, tree format_string_cst,
+			int char_idx, int opt, const char *gmsgid, ...)
+{
+  va_list ap;
+  va_start (ap, gmsgid);
+  tree string_type = TREE_TYPE (format_string_cst);
+
+  /* The callers are of the form:
+       format_warning (format_string_loc, format_string_cst,
+		       format_chars - orig_format_chars,
+      where format_chars has already been incremented, so that
+      CHAR_IDX is one character beyond where the warning should
+      be emitted.  Fix it.  */
+  char_idx -= 1;
+
+  substring_loc fmt_loc (fmt_string_loc, string_type, char_idx, char_idx);
+  bool warned = format_warning_va (fmt_loc, NULL, opt, gmsgid, &ap);
+  va_end (ap);
+
+  return warned;
 }
 
 /* Check that we have a pointer to a string suitable for use as a format.
@@ -1018,8 +1110,9 @@ format_flags (int format_num)
 static void check_format_info (function_format_info *, tree);
 static void check_format_arg (void *, tree, unsigned HOST_WIDE_INT);
 static void check_format_info_main (format_check_results *,
-				    function_format_info *,
-				    const char *, int, tree,
+				    function_format_info *, const char *,
+				    location_t, tree,
+				    int, tree,
 				    unsigned HOST_WIDE_INT,
 				    object_allocator<format_wanted_type> &);
 
@@ -1032,8 +1125,12 @@ static void finish_dollar_format_checking (format_check_results *, int);
 static const format_flag_spec *get_flag_spec (const format_flag_spec *,
 					      int, const char *);
 
-static void check_format_types (location_t, format_wanted_type *);
-static void format_type_warning (location_t, format_wanted_type *, tree, tree);
+static void check_format_types (const substring_loc &fmt_loc,
+				format_wanted_type *);
+static void format_type_warning (const substring_loc &fmt_loc,
+				 source_range *param_range,
+				 format_wanted_type *, tree,
+				 tree);
 
 /* Decode a format type from a string, returning the type, or
    format_type_error if not valid, in which case the caller should print an
@@ -1509,6 +1606,8 @@ check_format_arg (void *ctx, tree format_tree,
   tree array_size = 0;
   tree array_init;
 
+  location_t fmt_param_loc = EXPR_LOC_OR_LOC (format_tree, input_location);
+
   if (VAR_P (format_tree))
     {
       /* Pull out a constant value if the front end didn't.  */
@@ -1684,8 +1783,8 @@ check_format_arg (void *ctx, tree format_tree,
      need not adjust it for every return.  */
   res->number_other++;
   object_allocator <format_wanted_type> fwt_pool ("format_wanted_type pool");
-  check_format_info_main (res, info, format_chars, format_length,
-			  params, arg_num, fwt_pool);
+  check_format_info_main (res, info, format_chars, fmt_param_loc, format_tree,
+			  format_length, params, arg_num, fwt_pool);
 }
 
 /* Support class for argument_parser and check_format_info_main.
@@ -1702,6 +1801,7 @@ class flag_chars_t
 		 const format_char_info *fci,
 		 const format_flag_spec *flag_specs,
 		 const char * const format_chars,
+		 tree format_string_cst,
 		 location_t format_string_loc,
 		 const char * const orig_format_chars,
 		 char format_char);
@@ -1744,6 +1844,7 @@ class argument_parser
 {
  public:
   argument_parser (function_format_info *info, const char *&format_chars,
+		   tree format_string_cst,
 		   const char * const orig_format_chars,
 		   location_t format_string_loc, flag_chars_t &flag_chars,
 		   int &has_operand_number, tree first_fillin_param,
@@ -1799,13 +1900,16 @@ class argument_parser
 		       unsigned HOST_WIDE_INT &arg_num,
 		       tree &params,
 		       const int alloc_flag,
-		       const char * const format_start);
+		       const char * const format_start,
+		       location_t fmt_param_loc);
 
  private:
   const function_format_info *const info;
   const format_kind_info * const fki;
   const format_flag_spec * const flag_specs;
+  const char *start_of_this_format;
   const char *&format_chars;
+  const tree format_string_cst;
   const char * const orig_format_chars;
   const location_t format_string_loc;
   object_allocator <format_wanted_type> &fwt_pool;
@@ -1855,6 +1959,7 @@ flag_chars_t::validate (const format_kind_info *fki,
 			const format_char_info *fci,
 			const format_flag_spec *flag_specs,
 			const char * const format_chars,
+			tree format_string_cst,
 			location_t format_string_loc,
 			const char * const orig_format_chars,
 			char format_char)
@@ -1870,11 +1975,11 @@ flag_chars_t::validate (const format_kind_info *fki,
 	continue;
       if (strchr (fci->flag_chars, m_flag_chars[i]) == 0)
 	{
-	  warning_at (location_from_offset (format_string_loc,
-					    format_chars
-					    - orig_format_chars),
-		      OPT_Wformat_, "%s used with %<%%%c%> %s format",
-		      _(s->name), format_char, fki->name);
+	  format_warning_at_char (format_string_loc, format_string_cst,
+				  format_chars - orig_format_chars,
+				  OPT_Wformat_,
+				  "%s used with %<%%%c%> %s format",
+				  _(s->name), format_char, fki->name);
 	  d++;
 	  continue;
 	}
@@ -1935,6 +2040,7 @@ flag_chars_t::assignment_suppression_p (const format_kind_info *fki)
 
 argument_parser::
 argument_parser (function_format_info *info_, const char *&format_chars_,
+		 tree format_string_cst_,
 		 const char * const orig_format_chars_,
 		 location_t format_string_loc_,
 		 flag_chars_t &flag_chars_,
@@ -1944,7 +2050,9 @@ argument_parser (function_format_info *info_, const char *&format_chars_,
 : info (info_),
   fki (&format_types[info->format_type]),
   flag_specs (fki->flag_specs),
+  start_of_this_format (format_chars_),
   format_chars (format_chars_),
+  format_string_cst (format_string_cst_),
   orig_format_chars (orig_format_chars_),
   format_string_loc (format_string_loc_),
   fwt_pool (fwt_pool_),
@@ -2008,11 +2116,10 @@ argument_parser::read_format_flags ()
 						 *format_chars, NULL);
       if (flag_chars.has_char_p (*format_chars))
 	{
-	  warning_at (location_from_offset (format_string_loc,
-					    format_chars + 1
-					    - orig_format_chars),
-		      OPT_Wformat_,
-		      "repeated %s in format", _(s->name));
+	  format_warning_at_char (format_string_loc, format_string_cst,
+				  format_chars + 1 - orig_format_chars,
+				  OPT_Wformat_,
+				  "repeated %s in format", _(s->name));
 	}
       else
 	flag_chars.add_char (*format_chars);
@@ -2145,10 +2252,10 @@ argument_parser::read_any_format_left_precision ()
   ++format_chars;
   flag_chars.add_char (fki->left_precision_char);
   if (!ISDIGIT (*format_chars))
-    warning_at (location_from_offset (format_string_loc,
-				      format_chars - orig_format_chars),
-		OPT_Wformat_,
-		"empty left precision in %s format", fki->name);
+    format_warning_at_char (format_string_loc, format_string_cst,
+			    format_chars - orig_format_chars,
+			    OPT_Wformat_,
+			    "empty left precision in %s format", fki->name);
   while (ISDIGIT (*format_chars))
     ++format_chars;
 }
@@ -2236,10 +2343,10 @@ read_any_format_precision (tree &params,
     {
       if (!(fki->flags & (int) FMT_FLAG_EMPTY_PREC_OK)
 	  && !ISDIGIT (*format_chars))
-	warning_at (location_from_offset (format_string_loc,
-					  format_chars - orig_format_chars),
-		    OPT_Wformat_,
-		    "empty precision in %s format", fki->name);
+	format_warning_at_char (format_string_loc, format_string_cst,
+				format_chars - orig_format_chars,
+				OPT_Wformat_,
+				"empty precision in %s format", fki->name);
       while (ISDIGIT (*format_chars))
 	++format_chars;
     }
@@ -2340,11 +2447,10 @@ argument_parser::read_any_other_modifier ()
 	{
 	  const format_flag_spec *s = get_flag_spec (flag_specs,
 						     *format_chars, NULL);
-	  warning_at (location_from_offset (format_string_loc,
-					    format_chars
-					    - orig_format_chars),
-		      OPT_Wformat_,
-		      "repeated %s in format", _(s->name));
+	  format_warning_at_char (format_string_loc, format_string_cst,
+				  format_chars - orig_format_chars,
+				  OPT_Wformat_,
+				  "repeated %s in format", _(s->name));
 	}
       else
 	flag_chars.add_char (*format_chars);
@@ -2372,28 +2478,30 @@ argument_parser::find_format_char_info (char format_char)
   if (fci->format_chars == 0)
     {
       if (ISGRAPH (format_char))
-	warning_at (location_from_offset (format_string_loc,
-					  format_chars - orig_format_chars),
-		    OPT_Wformat_,
-		    "unknown conversion type character %qc in format",
-		    format_char);
+	format_warning_at_char (format_string_loc, format_string_cst,
+				format_chars - orig_format_chars,
+				OPT_Wformat_,
+				"unknown conversion type character"
+				" %qc in format",
+				format_char);
       else
-	warning_at (location_from_offset (format_string_loc,
-					  format_chars - orig_format_chars),
-		    OPT_Wformat_,
-		    "unknown conversion type character 0x%x in format",
-		    format_char);
+	format_warning_at_char (format_string_loc, format_string_cst,
+				format_chars - orig_format_chars,
+				OPT_Wformat_,
+				"unknown conversion type character"
+				" 0x%x in format",
+				format_char);
       return NULL;
     }
 
   if (pedantic)
     {
       if (ADJ_STD (fci->std) > C_STD_VER)
-	warning_at (location_from_offset (format_string_loc,
-					  format_chars - orig_format_chars),
-		    OPT_Wformat_,
-		    "%s does not support the %<%%%c%> %s format",
-		    C_STD_NAME (fci->std), format_char, fki->name);
+	format_warning_at_char (format_string_loc, format_string_cst,
+				format_chars - orig_format_chars,
+				OPT_Wformat_,
+				"%s does not support the %<%%%c%> %s format",
+				C_STD_NAME (fci->std), format_char, fki->name);
     }
 
   return fci;
@@ -2496,10 +2604,10 @@ argument_parser::parse_any_scan_set (const format_char_info *fci)
     ++format_chars;
   if (*format_chars != ']')
     /* The end of the format string was reached.  */
-    warning_at (location_from_offset (format_string_loc,
-				      format_chars - orig_format_chars),
-		OPT_Wformat_,
-		"no closing %<]%> for %<%%[%> format");
+    format_warning_at_char (format_string_loc, format_string_cst,
+			    format_chars - orig_format_chars,
+			    OPT_Wformat_,
+			    "no closing %<]%> for %<%%[%> format");
 }
 
 /* Return true if this argument is to be continued to be parsed,
@@ -2525,12 +2633,13 @@ argument_parser::handle_conversions (const format_char_info *fci,
   wanted_type_std = fci->types[len_modifier.val].std;
   if (wanted_type == 0)
     {
-      warning_at (location_from_offset (format_string_loc,
-					format_chars - orig_format_chars),
-		  OPT_Wformat_,
-		  "use of %qs length modifier with %qc type character"
-		  " has either no effect or undefined behavior",
-		  len_modifier.chars, format_char);
+      format_warning_at_char (format_string_loc, format_string_cst,
+			      format_chars - orig_format_chars,
+			      OPT_Wformat_,
+			      "use of %qs length modifier with %qc type"
+			      " character has either no effect"
+			      " or undefined behavior",
+			      len_modifier.chars, format_char);
       /* Heuristic: skip one argument when an invalid length/type
 	 combination is encountered.  */
       arg_num++;
@@ -2546,12 +2655,13 @@ argument_parser::handle_conversions (const format_char_info *fci,
 	   && ADJ_STD (wanted_type_std) > ADJ_STD (fci->std))
     {
       if (ADJ_STD (wanted_type_std) > C_STD_VER)
-	warning_at (location_from_offset (format_string_loc,
-					  format_chars - orig_format_chars),
-		    OPT_Wformat_,
-		    "%s does not support the %<%%%s%c%> %s format",
-		    C_STD_NAME (wanted_type_std), len_modifier.chars,
-		    format_char, fki->name);
+	format_warning_at_char (format_string_loc, format_string_cst,
+				format_chars - orig_format_chars,
+				OPT_Wformat_,
+				"%s does not support the %<%%%s%c%> %s format",
+				C_STD_NAME (wanted_type_std),
+				len_modifier.chars,
+				format_char, fki->name);
     }
 
   return true;
@@ -2571,7 +2681,8 @@ check_argument_type (const format_char_info *fci,
 		     unsigned HOST_WIDE_INT &arg_num,
 		     tree &params,
 		     const int alloc_flag,
-		     const char * const format_start)
+		     const char * const format_start,
+		     location_t fmt_param_loc)
 {
   if (info->first_arg_num == 0)
     return true;
@@ -2670,7 +2781,13 @@ check_argument_type (const format_char_info *fci,
     }
 
   if (first_wanted_type != 0)
-    check_format_types (format_string_loc, first_wanted_type);
+    {
+      ptrdiff_t offset_to_format_start = (start_of_this_format - 1) - orig_format_chars;
+      ptrdiff_t offset_to_format_end = (format_chars - 1) - orig_format_chars;
+      substring_loc fmt_loc (fmt_param_loc, TREE_TYPE (format_string_cst),
+			     offset_to_format_start, offset_to_format_end);
+      check_format_types (fmt_loc, first_wanted_type);
+    }
 
   return true;
 }
@@ -2685,6 +2802,7 @@ check_argument_type (const format_char_info *fci,
 static void
 check_format_info_main (format_check_results *res,
 			function_format_info *info, const char *format_chars,
+			location_t fmt_param_loc, tree format_string_cst,
 			int format_length, tree params,
 			unsigned HOST_WIDE_INT arg_num,
 			object_allocator <format_wanted_type> &fwt_pool)
@@ -2708,10 +2826,10 @@ check_format_info_main (format_check_results *res,
 	continue;
       if (*format_chars == 0)
 	{
-          warning_at (location_from_offset (format_string_loc,
-					    format_chars - orig_format_chars),
-		      OPT_Wformat_,
-		      "spurious trailing %<%%%> in format");
+	  format_warning_at_char (format_string_loc, format_string_cst,
+				  format_chars - orig_format_chars,
+				  OPT_Wformat_,
+				  "spurious trailing %<%%%> in format");
 	  continue;
 	}
       if (*format_chars == '%')
@@ -2721,8 +2839,8 @@ check_format_info_main (format_check_results *res,
 	}
 
       flag_chars_t flag_chars;
-      argument_parser arg_parser (info, format_chars, orig_format_chars,
-				  format_string_loc,
+      argument_parser arg_parser (info, format_chars, format_string_cst,
+				  orig_format_chars, format_string_loc,
 				  flag_chars, has_operand_number,
 				  first_fillin_param, fwt_pool);
 
@@ -2759,10 +2877,10 @@ check_format_info_main (format_check_results *res,
 	  || (!(fki->flags & (int) FMT_FLAG_FANCY_PERCENT_OK)
 	      && format_char == '%'))
 	{
-	  warning_at (location_from_offset (format_string_loc,
-					    format_chars - orig_format_chars),
-		      OPT_Wformat_,
-		      "conversion lacks type at end of format");
+	  format_warning_at_char (format_string_loc, format_string_cst,
+			     format_chars - orig_format_chars,
+			     OPT_Wformat_,
+			     "conversion lacks type at end of format");
 	  continue;
 	}
       format_chars++;
@@ -2773,6 +2891,7 @@ check_format_info_main (format_check_results *res,
 	continue;
 
       flag_chars.validate (fki, fci, flag_specs, format_chars,
+			   format_string_cst,
 			   format_string_loc, orig_format_chars, format_char);
 
       const int alloc_flag = flag_chars.get_alloc_flag (fki);
@@ -2803,15 +2922,15 @@ check_format_info_main (format_check_results *res,
 					   suppressed,
 					   arg_num, params,
 					   alloc_flag,
-					   format_start))
+					   format_start, fmt_param_loc))
 	return;
     }
 
   if (format_chars - orig_format_chars != format_length)
-    warning_at (location_from_offset (format_string_loc,
-				      format_chars + 1 - orig_format_chars),
-		OPT_Wformat_contains_nul,
-		"embedded %<\\0%> in format");
+    format_warning_at_char (format_string_loc, format_string_cst,
+			    format_chars + 1 - orig_format_chars,
+			    OPT_Wformat_contains_nul,
+			    "embedded %<\\0%> in format");
   if (info->first_arg_num != 0 && params != 0
       && has_operand_number <= 0)
     {
@@ -2822,12 +2941,12 @@ check_format_info_main (format_check_results *res,
     finish_dollar_format_checking (res, fki->flags & (int) FMT_FLAG_DOLLAR_GAP_POINTER_OK);
 }
 
-
 /* Check the argument types from a single format conversion (possibly
-   including width and precision arguments).  LOC is the location of
-   the format string.  */
+   including width and precision arguments).  FMT_LOC is the
+   location of the format conversion.  */
 static void
-check_format_types (location_t loc, format_wanted_type *types)
+check_format_types (const substring_loc &fmt_loc,
+		    format_wanted_type *types)
 {
   for (; types != 0; types = types->next)
     {
@@ -2854,7 +2973,7 @@ check_format_types (location_t loc, format_wanted_type *types)
       cur_param = types->param;
       if (!cur_param)
         {
-          format_type_warning (loc, types, wanted_type, NULL);
+          format_type_warning (fmt_loc, NULL, types, wanted_type, NULL);
           continue;
         }
 
@@ -2864,6 +2983,16 @@ check_format_types (location_t loc, format_wanted_type *types)
       orig_cur_type = cur_type;
       char_type_flag = 0;
 
+      source_range param_range;
+      source_range *param_range_ptr;
+      if (CAN_HAVE_LOCATION_P (cur_param))
+	{
+	  param_range = EXPR_LOCATION_RANGE (cur_param);
+	  param_range_ptr = &param_range;
+	}
+      else
+	param_range_ptr = NULL;
+
       STRIP_NOPS (cur_param);
 
       /* Check the types of any additional pointer arguments
@@ -2928,7 +3057,8 @@ check_format_types (location_t loc, format_wanted_type *types)
 	    }
 	  else
 	    {
-              format_type_warning (loc, types, wanted_type, orig_cur_type);
+	      format_type_warning (fmt_loc, param_range_ptr,
+				   types, wanted_type, orig_cur_type);
 	      break;
 	    }
 	}
@@ -2996,20 +3126,24 @@ check_format_types (location_t loc, format_wanted_type *types)
 	  && TYPE_PRECISION (cur_type) == TYPE_PRECISION (wanted_type))
 	continue;
       /* Now we have a type mismatch.  */
-      format_type_warning (loc, types, wanted_type, orig_cur_type);
+      format_type_warning (fmt_loc, param_range_ptr, types,
+			   wanted_type, orig_cur_type);
     }
 }
 
 
-/* Give a warning at LOC about a format argument of different type from that
-   expected.  WANTED_TYPE is the type the argument should have, possibly
-   stripped of pointer dereferences.  The description (such as "field
+/* Give a warning at FMT_LOC about a format argument of different type
+   from that expected.  If non-NULL, PARAM_RANGE is the source range of the
+   relevant argument.  WANTED_TYPE is the type the argument should have,
+   possibly stripped of pointer dereferences.  The description (such as "field
    precision"), the placement in the format string, a possibly more
    friendly name of WANTED_TYPE, and the number of pointer dereferences
    are taken from TYPE.  ARG_TYPE is the type of the actual argument,
    or NULL if it is missing.  */
 static void
-format_type_warning (location_t loc, format_wanted_type *type,
+format_type_warning (const substring_loc &fmt_loc,
+		     source_range *param_range,
+		     format_wanted_type *type,
 		     tree wanted_type, tree arg_type)
 {
   int kind = type->kind;
@@ -3018,7 +3152,6 @@ format_type_warning (location_t loc, format_wanted_type *type,
   int format_length = type->format_length;
   int pointer_count = type->pointer_count;
   int arg_num = type->arg_num;
-  unsigned int offset_loc = type->offset_loc;
 
   char *p;
   /* If ARG_TYPE is a typedef with a misleading name (for example,
@@ -3052,41 +3185,47 @@ format_type_warning (location_t loc, format_wanted_type *type,
       p[pointer_count + 1] = 0;
     }
 
-  loc = location_from_offset (loc, offset_loc);
-		      
   if (wanted_type_name)
     {
       if (arg_type)
-        warning_at (loc, OPT_Wformat_,
-		    "%s %<%s%.*s%> expects argument of type %<%s%s%>, "
-		    "but argument %d has type %qT",
-		    gettext (kind_descriptions[kind]),
-		    (kind == CF_KIND_FORMAT ? "%" : ""),
-		    format_length, format_start, 
-		    wanted_type_name, p, arg_num, arg_type);
+	format_warning_at_substring
+	  (fmt_loc, param_range,
+	   OPT_Wformat_,
+	   "%s %<%s%.*s%> expects argument of type %<%s%s%>, "
+	   "but argument %d has type %qT",
+	   gettext (kind_descriptions[kind]),
+	   (kind == CF_KIND_FORMAT ? "%" : ""),
+	   format_length, format_start,
+	   wanted_type_name, p, arg_num, arg_type);
       else
-        warning_at (loc, OPT_Wformat_,
-		    "%s %<%s%.*s%> expects a matching %<%s%s%> argument",
-		    gettext (kind_descriptions[kind]),
-		    (kind == CF_KIND_FORMAT ? "%" : ""),
-		    format_length, format_start, wanted_type_name, p);
+	format_warning_at_substring
+	  (fmt_loc, param_range,
+	   OPT_Wformat_,
+	   "%s %<%s%.*s%> expects a matching %<%s%s%> argument",
+	   gettext (kind_descriptions[kind]),
+	   (kind == CF_KIND_FORMAT ? "%" : ""),
+	   format_length, format_start, wanted_type_name, p);
     }
   else
     {
       if (arg_type)
-        warning_at (loc, OPT_Wformat_,
-		    "%s %<%s%.*s%> expects argument of type %<%T%s%>, "
-		    "but argument %d has type %qT",
-		    gettext (kind_descriptions[kind]),
-		    (kind == CF_KIND_FORMAT ? "%" : ""),
-		    format_length, format_start, 
-		    wanted_type, p, arg_num, arg_type);
+	format_warning_at_substring
+	  (fmt_loc, param_range,
+	   OPT_Wformat_,
+	   "%s %<%s%.*s%> expects argument of type %<%T%s%>, "
+	   "but argument %d has type %qT",
+	   gettext (kind_descriptions[kind]),
+	   (kind == CF_KIND_FORMAT ? "%" : ""),
+	   format_length, format_start,
+	   wanted_type, p, arg_num, arg_type);
       else
-        warning_at (loc, OPT_Wformat_,
-		    "%s %<%s%.*s%> expects a matching %<%T%s%> argument",
-		    gettext (kind_descriptions[kind]),
-		    (kind == CF_KIND_FORMAT ? "%" : ""),
-		    format_length, format_start, wanted_type, p);
+	format_warning_at_substring
+	  (fmt_loc, param_range,
+	   OPT_Wformat_,
+	   "%s %<%s%.*s%> expects a matching %<%T%s%> argument",
+	   gettext (kind_descriptions[kind]),
+	   (kind == CF_KIND_FORMAT ? "%" : ""),
+	   format_length, format_start, wanted_type, p);
     }
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5e34b8595da..6e406f6de8c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2016-08-08  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c/52952
+	* gcc.dg/cpp/pr66415-1.c: Likewise.
+	* gcc.dg/format/asm_fprintf-1.c: Update column numbers.
+	* gcc.dg/format/c90-printf-1.c: Likewise.
+	* gcc.dg/format/diagnostic-ranges.c: New test case.
+
 2016-08-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR fortran/72716
diff --git a/gcc/testsuite/gcc.dg/cpp/pr66415-1.c b/gcc/testsuite/gcc.dg/cpp/pr66415-1.c
index 349ec4883fa..1f67cb4f84c 100644
--- a/gcc/testsuite/gcc.dg/cpp/pr66415-1.c
+++ b/gcc/testsuite/gcc.dg/cpp/pr66415-1.c
@@ -1,9 +1,15 @@
 /* PR c/66415 */
 /* { dg-do compile } */
-/* { dg-options "-Wformat" } */
+/* { dg-options "-Wformat -fdiagnostics-show-caret" } */
 
 void
 fn1 (void)
 {
   __builtin_printf                                ("xxxxxxxxxxxxxxxxx%dxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); /* { dg-warning "71:format" } */
+
+/* { dg-begin-multiline-output "" }
+   __builtin_printf                                ("xxxxxxxxxxxxxxxxx%dxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
+                                                                      ~^
+   { dg-end-multiline-output "" } */
+
 }
diff --git a/gcc/testsuite/gcc.dg/format/asm_fprintf-1.c b/gcc/testsuite/gcc.dg/format/asm_fprintf-1.c
index 2eabbf9190e..50ca57206b1 100644
--- a/gcc/testsuite/gcc.dg/format/asm_fprintf-1.c
+++ b/gcc/testsuite/gcc.dg/format/asm_fprintf-1.c
@@ -66,9 +66,9 @@ foo (int i, int i1, int i2, unsigned int u, double d, char *s, void *p,
   asm_fprintf ("%d", i, i); /* { dg-warning "16:arguments" "wrong number of args" } */
   /* Miscellaneous bogus constructions.  */
   asm_fprintf (""); /* { dg-warning "16:zero-length" "warning for empty format" } */
-  asm_fprintf ("\0"); /* { dg-warning "17:embedded" "warning for embedded NUL" } */
-  asm_fprintf ("%d\0", i); /* { dg-warning "19:embedded" "warning for embedded NUL" } */
-  asm_fprintf ("%d\0%d", i, i); /* { dg-warning "19:embedded|too many" "warning for embedded NUL" } */
+  asm_fprintf ("\0"); /* { dg-warning "18:embedded" "warning for embedded NUL" } */
+  asm_fprintf ("%d\0", i); /* { dg-warning "20:embedded" "warning for embedded NUL" } */
+  asm_fprintf ("%d\0%d", i, i); /* { dg-warning "20:embedded|too many" "warning for embedded NUL" } */
   asm_fprintf (NULL); /* { dg-warning "null" "null format string warning" } */
   asm_fprintf ("%"); /* { dg-warning "17:trailing" "trailing % warning" } */
   asm_fprintf ("%++d", i); /* { dg-warning "19:repeated" "repeated flag warning" } */
diff --git a/gcc/testsuite/gcc.dg/format/c90-printf-1.c b/gcc/testsuite/gcc.dg/format/c90-printf-1.c
index 5329dad83a4..338b971da09 100644
--- a/gcc/testsuite/gcc.dg/format/c90-printf-1.c
+++ b/gcc/testsuite/gcc.dg/format/c90-printf-1.c
@@ -58,11 +58,11 @@ foo (int i, int i1, int i2, unsigned int u, double d, char *s, void *p,
   printf ("%-%"); /* { dg-warning "13:type" "missing type" } */
   /* { dg-warning "14:trailing" "bogus %%" { target *-*-* } 58 } */
   printf ("%-%\n"); /* { dg-warning "13:format" "bogus %%" } */
-  /* { dg-warning "15:format" "bogus %%" { target *-*-* } 60 } */
+  /* { dg-warning "16:format" "bogus %%" { target *-*-* } 60 } */
   printf ("%5%\n"); /* { dg-warning "13:format" "bogus %%" } */
-  /* { dg-warning "15:format" "bogus %%" { target *-*-* } 62 } */
+  /* { dg-warning "16:format" "bogus %%" { target *-*-* } 62 } */
   printf ("%h%\n"); /* { dg-warning "13:format" "bogus %%" } */
-  /* { dg-warning "15:format" "bogus %%" { target *-*-* } 64 } */
+  /* { dg-warning "16:format" "bogus %%" { target *-*-* } 64 } */
   /* Valid and invalid %h, %l, %L constructions.  */
   printf ("%hd", i);
   printf ("%hi", i);
@@ -184,8 +184,8 @@ foo (int i, int i1, int i2, unsigned int u, double d, char *s, void *p,
   printf ("%-08G", d); /* { dg-warning "11:flags|ignored" "0 flag ignored with - flag" } */
   /* Various tests of bad argument types.  */
   printf ("%d", l); /* { dg-warning "13:format" "bad argument types" } */
-  printf ("%*.*d", l, i2, i); /* { dg-warning "13:field" "bad * argument types" } */
-  printf ("%*.*d", i1, l, i); /* { dg-warning "15:field" "bad * argument types" } */
+  printf ("%*.*d", l, i2, i); /* { dg-warning "16:field" "bad * argument types" } */
+  printf ("%*.*d", i1, l, i); /* { dg-warning "16:field" "bad * argument types" } */
   printf ("%ld", i); /* { dg-warning "14:format" "bad argument types" } */
   printf ("%s", n); /* { dg-warning "13:format" "bad argument types" } */
   printf ("%p", i); /* { dg-warning "13:format" "bad argument types" } */
@@ -231,8 +231,8 @@ foo (int i, int i1, int i2, unsigned int u, double d, char *s, void *p,
   printf ("%d", i, i); /* { dg-warning "11:arguments" "wrong number of args" } */
   /* Miscellaneous bogus constructions.  */
   printf (""); /* { dg-warning "11:zero-length" "warning for empty format" } */
-  printf ("\0"); /* { dg-warning "12:embedded" "warning for embedded NUL" } */
-  printf ("%d\0", i); /* { dg-warning "14:embedded" "warning for embedded NUL" } */
+  printf ("\0"); /* { dg-warning "13:embedded" "warning for embedded NUL" } */
+  printf ("%d\0", i); /* { dg-warning "15:embedded" "warning for embedded NUL" } */
   printf ("%d\0%d", i, i); /* { dg-warning "embedded|too many" "warning for embedded NUL" } */
   printf (NULL); /* { dg-warning "3:null" "null format string warning" } */
   printf ("%"); /* { dg-warning "12:trailing" "trailing % warning" } */
diff --git a/gcc/testsuite/gcc.dg/format/diagnostic-ranges.c b/gcc/testsuite/gcc.dg/format/diagnostic-ranges.c
new file mode 100644
index 00000000000..9e86b5210f1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/diagnostic-ranges.c
@@ -0,0 +1,222 @@
+/* { dg-options "-Wformat -fdiagnostics-show-caret" } */
+
+/* See PR 52952. */
+
+#include "format.h"
+
+void test_mismatching_types (const char *msg)
+{
+  printf("hello %i", msg);  /* { dg-warning "format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+
+/* TODO: ideally would also underline "msg".  */
+/* { dg-begin-multiline-output "" }
+   printf("hello %i", msg);
+                 ~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_multiple_arguments (void)
+{
+  printf ("arg0: %i  arg1: %s arg 2: %i", /* { dg-warning "29: format '%s'" } */
+          100, 101, 102);
+/* TODO: ideally would also underline "101".  */
+/* { dg-begin-multiline-output "" }
+   printf ("arg0: %i  arg1: %s arg 2: %i",
+                            ~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_multiple_arguments_2 (int i, int j)
+{
+  printf ("arg0: %i  arg1: %s arg 2: %i", /* { dg-warning "29: format '%s'" } */
+          100, i + j, 102);
+/* { dg-begin-multiline-output "" }
+   printf ("arg0: %i  arg1: %s arg 2: %i",
+                            ~^
+           100, i + j, 102);
+                ~~~~~         
+   { dg-end-multiline-output "" } */
+}
+
+void multiline_format_string (void) {
+  printf ("before the fmt specifier" /* { dg-warning "11: format '%d' expects a matching 'int' argument" } */
+/* { dg-begin-multiline-output "" }
+   printf ("before the fmt specifier"
+           ^~~~~~~~~~~~~~~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+
+          "%"
+          "d" /* { dg-message "12: format string is defined here" } */
+          "after the fmt specifier");
+
+/* { dg-begin-multiline-output "" }
+           "%"
+            ~~
+           "d"
+           ~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_hex (const char *msg)
+{
+  /* "%" is \x25
+     "i" is \x69 */
+  printf("hello \x25\x69", msg);  /* { dg-warning "format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+
+/* TODO: ideally would also underline "msg".  */
+/* { dg-begin-multiline-output "" }
+   printf("hello \x25\x69", msg);
+                 ~~~~~~~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_oct (const char *msg)
+{
+  /* "%" is octal 045
+     "i" is octal 151.  */
+  printf("hello \045\151", msg);  /* { dg-warning "format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+
+/* TODO: ideally would also underline "msg".  */
+/* { dg-begin-multiline-output "" }
+   printf("hello \045\151", msg);
+                 ~~~~~~~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_multiple (const char *msg)
+{
+  /* "%" is \x25 in hex
+     "i" is \151 in octal.  */
+  printf("prefix"  "\x25"  "\151"  "suffix",  /* { dg-warning "format '%i'" } */
+         msg);
+/* { dg-begin-multiline-output "" }
+   printf("prefix"  "\x25"  "\151"  "suffix",
+          ^~~~~~~~
+  { dg-end-multiline-output "" } */
+
+/* TODO: ideally would also underline "msg".  */
+/* { dg-begin-multiline-output "" }
+   printf("prefix"  "\x25"  "\151"  "suffix",
+                     ~~~~~~~~~~~^
+  { dg-end-multiline-output "" } */
+}
+
+void test_u8 (const char *msg)
+{
+  printf(u8"hello %i", msg);/* { dg-warning "format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+/* TODO: ideally would also underline "msg".  */
+/* { dg-begin-multiline-output "" }
+   printf(u8"hello %i", msg);
+                   ~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_param (long long_i, long long_j)
+{
+  printf ("foo %s bar", long_i + long_j); /* { dg-warning "17: format '%s' expects argument of type 'char \\*', but argument 2 has type 'long int'" } */
+/* { dg-begin-multiline-output "" }
+   printf ("foo %s bar", long_i + long_j);
+                ~^       ~~~~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+}
+
+void test_field_width_specifier (long l, int i1, int i2)
+{
+  printf (" %*.*d ", l, i1, i2); /* { dg-warning "17: field width specifier '\\*' expects argument of type 'int', but argument 2 has type 'long int'" } */
+/* { dg-begin-multiline-output "" }
+   printf (" %*.*d ", l, i1, i2);
+             ~~~~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_spurious_percent (void)
+{
+  printf("hello world %"); /* { dg-warning "23: spurious trailing" } */
+
+/* { dg-begin-multiline-output "" }
+   printf("hello world %");
+                       ^
+   { dg-end-multiline-output "" } */
+}
+
+void test_empty_precision (char *s, size_t m, double d)
+{
+  strfmon (s, m, "%#.5n", d); /* { dg-warning "20: empty left precision in gnu_strfmon format" } */
+/* { dg-begin-multiline-output "" }
+   strfmon (s, m, "%#.5n", d);
+                    ^
+   { dg-end-multiline-output "" } */
+
+  strfmon (s, m, "%#5.n", d); /* { dg-warning "22: empty precision in gnu_strfmon format" } */
+/* { dg-begin-multiline-output "" }
+   strfmon (s, m, "%#5.n", d);
+                      ^
+   { dg-end-multiline-output "" } */
+}
+
+void test_repeated (int i)
+{
+  printf ("%++d", i); /* { dg-warning "14: repeated '\\+' flag in format" } */
+/* { dg-begin-multiline-output "" }
+   printf ("%++d", i);
+              ^
+   { dg-end-multiline-output "" } */
+}
+
+void test_conversion_lacks_type (void)
+{
+  printf (" %h"); /* { dg-warning "14:conversion lacks type at end of format" } */
+/* { dg-begin-multiline-output "" }
+   printf (" %h");
+              ^
+   { dg-end-multiline-output "" } */
+}
+
+void test_embedded_nul (void)
+{
+  printf (" \0 "); /* { dg-warning "14:embedded" "warning for embedded NUL" } */
+/* { dg-begin-multiline-output "" }
+   printf (" \0 ");
+             ~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_macro (const char *msg)
+{
+#define INT_FMT "%i" /* { dg-message "19: format string is defined here" } */
+  printf("hello " INT_FMT " world", msg);  /* { dg-warning "10: format '%i' expects argument of type 'int', but argument 2 has type 'const char \\*' " } */
+/* { dg-begin-multiline-output "" }
+   printf("hello " INT_FMT " world", msg);
+          ^~~~~~~~
+   { dg-end-multiline-output "" } */
+/* { dg-begin-multiline-output "" }
+ #define INT_FMT "%i"
+                  ~^
+   { 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-begin-multiline-output "" }
+   __builtin_printf(" %" "d ", 0.5);
+                    ^~~~
+   { dg-end-multiline-output "" } */
+  /* { dg-begin-multiline-output "" }
+   __builtin_printf(" %" "d ", 0.5);
+                      ~~~~^
+   { dg-end-multiline-output "" } */
+}
+
+void test_const_arrays (void)
+{
+  /* TODO: ideally we'd highlight both the format string *and* the use of
+     it here.  For now, just verify that we gracefully handle this case.  */
+  const char a[] = " %d ";
+  __builtin_printf(a, 0.5); /* { dg-warning "20: format .%d. expects argument of type .int., but argument 2 has type .double." } */
+  /* { dg-begin-multiline-output "" }
+   __builtin_printf(a, 0.5);
+                    ^
+   { dg-end-multiline-output "" } */
+}