Diagnostic for module importation

This tweaks the 'included from ...' printing to deal with imports in
the 'include' path.  One new thing is that there can now be two
'include' names on a single line.  For example 'in module X, included
at Y'.  This reads better than placing them on different lines.

	gcc/
	* diagnostic.c (diagnostic_report_current_module): Adjust for C++
	module importation.

1 files changed, 16 insertions, 5 deletions

diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
index 1b6c984..fe509d8 100644
--- a/gcc/diagnostic.c
+++ b/gcc/diagnostic.c
@@ -689,12 +689,13 @@ diagnostic_report_current_module (diagnostic_context *context, location_t where)
       set_last_module (context, map);
       if (! MAIN_FILE_P (map))
 	{
-	  bool first = true;
+	  bool first = true, need_inc = true, was_module = MAP_MODULE_P (map);
 	  expanded_location s = {};
 	  do
 	    {
 	      where = linemap_included_from (map);
 	      map = linemap_included_from_linemap (line_table, map);
+	      bool is_module = MAP_MODULE_P (map);
 	      s.file = LINEMAP_FILE (map);
 	      s.line = SOURCE_LINE (map, where);
 	      int col = -1;
@@ -706,14 +707,24 @@ diagnostic_report_current_module (diagnostic_context *context, location_t where)
 	      const char *line_col = maybe_line_and_column (s.line, col);
 	      static const char *const msgs[] =
 		{
-		 N_("In file included from"),
+		 NULL,
 		 N_("                 from"),
+		 N_("In file included from"),	/* 2 */
+		 N_("        included from"),
+		 N_("In module"),		/* 4 */
+		 N_("of module"),
+		 N_("In module imported at"),	/* 6 */
+		 N_("imported at"),
 		};
-	      unsigned index = !first;
+
+	      unsigned index = (was_module ? 6 : is_module ? 4
+				: need_inc ? 2 : 0) + !first;
+
 	      pp_verbatim (context->printer, "%s%s %r%s%s%R",
-			   first ? "" : ",\n", _(msgs[index]),
+			   first ? "" : was_module ? ", " : ",\n",
+			   _(msgs[index]),
 			   "locus", s.file, line_col);
-	      first = false;
+	      first = false, need_inc = was_module, was_module = is_module;
 	    }
 	  while (! MAIN_FILE_P (map));
 	  pp_verbatim (context->printer, ":");