re PR c/52952 (Wformat location info is bad (wrong column number))

gcc/testsuite/ChangeLog:

2015-05-21  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c/52952
	* gcc.dg/redecl-4.c: Update column numbers.
	* gcc.dg/format/bitfld-1.c: Likewise.
	* gcc.dg/format/attr-2.c: Likewise.
	* gcc.dg/format/attr-6.c: Likewise.
	* gcc.dg/format/attr-7.c (baz): Likewise.
	* gcc.dg/format/asm_fprintf-1.c: Likewise.
	* gcc.dg/format/attr-4.c: Likewise.
	* gcc.dg/format/branch-1.c: Likewise.
	* gcc.dg/format/c90-printf-1.c: Likewise. Add tests for column
	locations within strings with embedded escape sequences.

gcc/c-family/ChangeLog:

2015-05-21  Manuel López-Ibáñez  <manu@gcc.gnu.org>
	
	PR c/52952
	* c-format.c (location_column_from_byte_offset): New.
	(location_from_offset): New.
	(struct format_wanted_type): Add offset_loc field.
	(check_format_info): Move handling of location for extra arguments
	closer to the point of warning.
	(check_format_info_main): Pass the result of location_from_offset
	to warning_at.
	(format_type_warning): Pass the result of location_from_offset
	to warning_at.

From-SVN: r223470

1 files changed, 136 insertions, 20 deletions

diff --git a/gcc/c-family/c-format.c b/gcc/c-family/c-format.c
index 9d03ff03834..145bbfd393f 100644
--- a/gcc/c-family/c-format.c
+++ b/gcc/c-family/c-format.c
@@ -78,6 +78,78 @@ 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.   */
+
+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;
+
+  c++, offset--;
+  while (offset > 0)
+    {
+      if (c - s >= line_width)
+	return 0;
+
+      switch (*c)
+	{
+	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;
+
+	    default:
+	      return 0;
+	    }
+	  break;
+
+	case '"':
+	  /* We found the end of the string too early.  */
+	  return 0;
+	  
+	default:
+	  c++, offset--;
+	  break;
+	}
+    }
+  return c - s;
+}
+
+/* Return a location that encodes the same location as LOC but shifted
+   by OFFSET bytes.  */
+
+static location_t
+location_from_offset (location_t loc, int offset)
+{
+  gcc_checking_assert (offset >= 0);
+  if (linemap_location_from_macro_expansion_p (line_table, loc)
+      || offset < 0)
+    return loc;
+
+  expanded_location s = expand_location_to_spelling_point (loc);
+  int line_width;
+  const char *line = location_get_source_line (s, &line_width);
+  line += s.column - 1 ;
+  line_width -= s.column - 1;
+  unsigned int column = 
+    location_column_from_byte_offset (line, line_width, (unsigned) offset);
+
+  return linemap_position_for_loc_and_offset (line_table, loc, column);
+}
+
 /* Check that we have a pointer to a string suitable for use as a format.
    The default is to check for a char type.
    For objective-c dialects, this is extended to include references to string
@@ -390,6 +462,9 @@ typedef struct format_wanted_type
   tree param;
   /* The argument number of that parameter.  */
   int arg_num;
+  /* The offset location of this argument with respect to the format
+     string location.  */
+  unsigned int offset_loc;
   /* The next type to check for this format conversion, or NULL if none.  */
   struct format_wanted_type *next;
 } format_wanted_type;
@@ -1358,8 +1433,6 @@ check_format_info (function_format_info *info, tree params)
 				    format_tree, arg_num);
 
   location_t loc = format_ctx.res->format_string_loc;
-  if (res.extra_arg_loc == UNKNOWN_LOCATION)
-    res.extra_arg_loc = loc;
 
   if (res.number_non_literal > 0)
     {
@@ -1405,8 +1478,12 @@ check_format_info (function_format_info *info, tree params)
      case of extra format arguments.  */
   if (res.number_extra_args > 0 && res.number_non_literal == 0
       && res.number_other == 0)
-    warning_at (res.extra_arg_loc, OPT_Wformat_extra_args,
-		"too many arguments for format");
+    {
+      if (res.extra_arg_loc == UNKNOWN_LOCATION)
+	res.extra_arg_loc = loc;
+      warning_at (res.extra_arg_loc, OPT_Wformat_extra_args,
+		  "too many arguments for format");
+    }
   if (res.number_dollar_extra_args > 0 && res.number_non_literal == 0
       && res.number_other == 0)
     warning_at (loc, OPT_Wformat_extra_args, "unused arguments in $-style format");
@@ -1682,7 +1759,9 @@ check_format_info_main (format_check_results *res,
 	continue;
       if (*format_chars == 0)
 	{
-          warning_at (format_string_loc, OPT_Wformat_,
+          warning_at (location_from_offset (format_string_loc,
+					    format_chars - orig_format_chars),
+		      OPT_Wformat_,
 		      "spurious trailing %<%%%> in format");
 	  continue;
 	}
@@ -1727,7 +1806,10 @@ check_format_info_main (format_check_results *res,
 						     *format_chars, NULL);
 	  if (strchr (flag_chars, *format_chars) != 0)
 	    {
-	      warning_at (format_string_loc, OPT_Wformat_,
+	      warning_at (location_from_offset (format_string_loc,
+						format_chars + 1
+						- orig_format_chars),
+			  OPT_Wformat_,
 			  "repeated %s in format", _(s->name));
 	    }
 	  else
@@ -1807,6 +1889,8 @@ check_format_info_main (format_check_results *res,
 		  width_wanted_type.format_length = 1;
 		  width_wanted_type.param = cur_param;
 		  width_wanted_type.arg_num = arg_num;
+		  width_wanted_type.offset_loc =
+		    format_chars - orig_format_chars;
 		  width_wanted_type.next = NULL;
 		  if (last_wanted_type != 0)
 		    last_wanted_type->next = &width_wanted_type;
@@ -1849,7 +1933,9 @@ check_format_info_main (format_check_results *res,
 	  flag_chars[i++] = fki->left_precision_char;
 	  flag_chars[i] = 0;
 	  if (!ISDIGIT (*format_chars))
-	    warning_at (format_string_loc, OPT_Wformat_,
+	    warning_at (location_from_offset (format_string_loc,
+					      format_chars - orig_format_chars),
+			OPT_Wformat_,
 			"empty left precision in %s format", fki->name);
 	  while (ISDIGIT (*format_chars))
 	    ++format_chars;
@@ -1914,6 +2000,8 @@ check_format_info_main (format_check_results *res,
 		  precision_wanted_type.format_start = format_chars - 2;
 		  precision_wanted_type.format_length = 2;
 		  precision_wanted_type.arg_num = arg_num;
+		  precision_wanted_type.offset_loc =
+		    format_chars - orig_format_chars;
 		  precision_wanted_type.next = NULL;
 		  if (last_wanted_type != 0)
 		    last_wanted_type->next = &precision_wanted_type;
@@ -1926,7 +2014,9 @@ check_format_info_main (format_check_results *res,
 	    {
 	      if (!(fki->flags & (int) FMT_FLAG_EMPTY_PREC_OK)
 		  && !ISDIGIT (*format_chars))
-		warning_at (format_string_loc, OPT_Wformat_,
+		warning_at (location_from_offset (format_string_loc,
+						  format_chars - orig_format_chars),
+			    OPT_Wformat_,
 			    "empty precision in %s format", fki->name);
 	      while (ISDIGIT (*format_chars))
 		++format_chars;
@@ -2012,7 +2102,10 @@ check_format_info_main (format_check_results *res,
 		{
 		  const format_flag_spec *s = get_flag_spec (flag_specs,
 							     *format_chars, NULL);
-		  warning_at (format_string_loc, OPT_Wformat_,
+		  warning_at (location_from_offset (format_string_loc,
+						    format_chars 
+						    - orig_format_chars),
+			      OPT_Wformat_,
 			      "repeated %s in format", _(s->name));
 		}
 	      else
@@ -2030,7 +2123,9 @@ check_format_info_main (format_check_results *res,
 	  || (!(fki->flags & (int) FMT_FLAG_FANCY_PERCENT_OK)
 	      && format_char == '%'))
 	{
-	  warning_at (format_string_loc, OPT_Wformat_,
+	  warning_at (location_from_offset (format_string_loc,
+					    format_chars - orig_format_chars),
+		      OPT_Wformat_,
 		      "conversion lacks type at end of format");
 	  continue;
 	}
@@ -2042,11 +2137,15 @@ check_format_info_main (format_check_results *res,
       if (fci->format_chars == 0)
 	{
 	  if (ISGRAPH (format_char))
-	    warning_at (format_string_loc, OPT_Wformat_,
+	    warning_at (location_from_offset (format_string_loc,
+					      format_chars - orig_format_chars),
+			OPT_Wformat_,
 			"unknown conversion type character %qc in format",
 			format_char);
 	  else
-	    warning_at (format_string_loc, OPT_Wformat_,
+	    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);
 	  continue;
@@ -2054,7 +2153,9 @@ check_format_info_main (format_check_results *res,
       if (pedantic)
 	{
 	  if (ADJ_STD (fci->std) > C_STD_VER)
-	    warning_at (format_string_loc, OPT_Wformat_,
+	    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);
 	}
@@ -2071,8 +2172,10 @@ check_format_info_main (format_check_results *res,
 	      continue;
 	    if (strchr (fci->flag_chars, flag_chars[i]) == 0)
 	      {
-		warning_at (format_string_loc, 
-                            OPT_Wformat_, "%s used with %<%%%c%> %s format",
+		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);
 		d++;
 		continue;
@@ -2186,7 +2289,9 @@ check_format_info_main (format_check_results *res,
 	    ++format_chars;
 	  if (*format_chars != ']')
 	    /* The end of the format string was reached.  */
-	    warning_at (format_string_loc, OPT_Wformat_,
+	    warning_at (location_from_offset (format_string_loc,
+					      format_chars - orig_format_chars),
+			OPT_Wformat_,
 			"no closing %<]%> for %<%%[%> format");
 	}
 
@@ -2200,8 +2305,11 @@ check_format_info_main (format_check_results *res,
 	  wanted_type_std = fci->types[length_chars_val].std;
 	  if (wanted_type == 0)
 	    {
-	      warning_at (format_string_loc, OPT_Wformat_,
-			  "use of %qs length modifier with %qc type character",
+	      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",
 			  length_chars, format_char);
 	      /* Heuristic: skip one argument when an invalid length/type
 		 combination is encountered.  */
@@ -2218,7 +2326,9 @@ check_format_info_main (format_check_results *res,
 		   && ADJ_STD (wanted_type_std) > ADJ_STD (fci->std))
 	    {
 	      if (ADJ_STD (wanted_type_std) > C_STD_VER)
-		warning_at (format_string_loc, OPT_Wformat_,
+		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), length_chars,
 			    format_char, fki->name);
@@ -2303,6 +2413,7 @@ check_format_info_main (format_check_results *res,
 	      wanted_type_ptr->arg_num = arg_num;
 	      wanted_type_ptr->format_start = format_start;
 	      wanted_type_ptr->format_length = format_chars - format_start;
+	      wanted_type_ptr->offset_loc = format_chars - orig_format_chars;
 	      wanted_type_ptr->next = NULL;
 	      if (last_wanted_type != 0)
 		last_wanted_type->next = wanted_type_ptr;
@@ -2327,7 +2438,9 @@ check_format_info_main (format_check_results *res,
     }
 
   if (format_chars - orig_format_chars != format_length)
-    warning_at (format_string_loc, OPT_Wformat_contains_nul,
+    warning_at (location_from_offset (format_string_loc,
+				      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)
@@ -2535,6 +2648,7 @@ 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,
@@ -2568,6 +2682,8 @@ 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)