Use char_span for return type of location_get_source_line

location_get_source_line returns a const char * that isn't 0-terminated,
writing back a length through an int * param.

This is error-prone, as all call-sites have to take into account the
lack of 0-termination, and respect the length of the buffer.

It's cleaner to bundle together this pointer+length state into a class,
so this patch does so, reusing the "char_span" class that I introduced
in r250187 (as part of the fix for PR c/81405).

The patch also adds assertions to all access to the char_span.

gcc/c-family/ChangeLog:
	* c-format.c (get_corrected_substring): Update for
	location_get_source_line returning a char_span.  Use a char_span
	when handling the prefix of the correction.
	* c-indentation.c (get_visual_column): Update for
	location_get_source_line returning a char_span.
	(get_first_nws_vis_column): Likewise.

gcc/ChangeLog:
	* diagnostic-show-locus.c (layout::layout): Update for
	location_get_source_line returning a char_span.
	(struct char_span): Move to input.h.
	(struct correction): Update for fields in char_span becoming
	private.
	(struct source_line): Update for location_get_source_line
	returning a char_span.
	(layout::print_line): Likewise.
	* edit-context.c (edited_file::print_content): Likewise.
	(edited_file::print_diff_hunk): Likewise.
	(edited_file::print_run_of_changed_lines): Likewise.
	(edited_file::get_num_lines): Likewise.
	(edited_line::edited_line): Likewise.
	* final.c (asm_show_source): Likewise.
	* input.c (location_get_source_line): Convert return type
	from const char * to char_span, losing the final "line_len"
	param.
	(dump_location_info): Update for the above.
	(get_substring_ranges_for_loc): Likewise.  Use a char_span
	when handling the literal within the line.
	(test_reading_source_line): Update for location_get_source_line
	returning a char_span.
	* input.h (class char_span): Move here from
	diagnostic-show-locus.c, converting from a struct to a class.
	Make data members private.
	(char_span::operator bool): New.
	(char_span::length): New.
	(char_span::get_buffer): New.
	(char_span::operator[]): New.
	(char_span::subspan): Make const.
	(char_span::xstrdup): New.
	(location_get_source_line): Convert return type from const char *
	to char_span, losing the final "line_size" param.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/diagnostic_plugin_test_show_locus.c
	(test_show_locus): Update for location_get_source_line returning a
	char_span.  Use char_span for handling words in the
	"test_many_nested_locations" fix-it example.

From-SVN: r259768

1 files changed, 12 insertions, 19 deletions

diff --git a/gcc/edit-context.c b/gcc/edit-context.c
index 9ac2dfc..3cdb88d 100644
--- a/gcc/edit-context.c
+++ b/gcc/edit-context.c
@@ -422,12 +422,10 @@ edited_file::print_content (pretty_printer *pp)
 	el->print_content (pp);
       else
 	{
-	  int len;
-	  const char *line
-	    = location_get_source_line (m_filename, line_num, &len);
+	  char_span line = location_get_source_line (m_filename, line_num);
 	  if (!line)
 	    return false;
-	  for (int i = 0; i < len; i++)
+	  for (size_t i = 0; i < line.length (); i++)
 	    pp_character (pp, line[i]);
 	}
       if (line_num < line_count)
@@ -543,10 +541,8 @@ edited_file::print_diff_hunk (pretty_printer *pp, int old_start_of_hunk,
       else
 	{
 	  /* Unchanged line.  */
-	  int line_len;
-	  const char *old_line
-	    = location_get_source_line (m_filename, line_num, &line_len);
-	  print_diff_line (pp, ' ', old_line, line_len);
+	  char_span old_line = location_get_source_line (m_filename, line_num);
+	  print_diff_line (pp, ' ', old_line.get_buffer (), old_line.length ());
 	  line_num++;
 	}
     }
@@ -574,10 +570,9 @@ edited_file::print_run_of_changed_lines (pretty_printer *pp,
       gcc_assert (el_in_run);
       if (el_in_run->actually_edited_p ())
 	{
-	  int line_len;
-	  const char *old_line
-	    = location_get_source_line (m_filename, line_num, &line_len);
-	  print_diff_line (pp, '-', old_line, line_len);
+	  char_span old_line = location_get_source_line (m_filename, line_num);
+	  print_diff_line (pp, '-', old_line.get_buffer (),
+			   old_line.length ());
 	}
     }
   pp_string (pp, colorize_stop (pp_show_color (pp)));
@@ -671,10 +666,8 @@ edited_file::get_num_lines (bool *missing_trailing_newline)
       m_num_lines = 0;
       while (true)
 	{
-	  int line_size;
-	  const char *line
-	    = location_get_source_line (m_filename, m_num_lines + 1,
-					&line_size);
+	  char_span line
+	    = location_get_source_line (m_filename, m_num_lines + 1);
 	  if (line)
 	    m_num_lines++;
 	  else
@@ -695,12 +688,12 @@ edited_line::edited_line (const char *filename, int line_num)
   m_line_events (),
   m_predecessors ()
 {
-  const char *line = location_get_source_line (filename, line_num,
-					       &m_len);
+  char_span line = location_get_source_line (filename, line_num);
   if (!line)
     return;
+  m_len = line.length ();
   ensure_capacity (m_len);
-  memcpy (m_content, line, m_len);
+  memcpy (m_content, line.get_buffer (), m_len);
   ensure_terminated ();
 }