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, 3 insertions, 4 deletions

diff --git a/gcc/final.c b/gcc/final.c
index 19817e2..4c600f0 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -2216,14 +2216,13 @@ asm_show_source (const char *filename, int linenum)
   if (!filename)
     return;
 
-  int line_size;
-  const char *line = location_get_source_line (filename, linenum, &line_size);
+  char_span line = location_get_source_line (filename, linenum);
   if (!line)
     return;
 
   fprintf (asm_out_file, "%s %s:%i: ", ASM_COMMENT_START, filename, linenum);
-  /* "line" is not 0-terminated, so we must use line_size.  */
-  fwrite (line, 1, line_size, asm_out_file);
+  /* "line" is not 0-terminated, so we must use its length.  */
+  fwrite (line.get_buffer (), 1, line.length (), asm_out_file);
   fputc ('\n', asm_out_file);
 }