Reimplement removal fix-it hints in terms of replace

This patch eliminates class fixit_remove, reimplementing
rich_location::add_fixit_remove in terms of replacement with the
empty string.  Deleting the removal subclass simplifies
fixit-handling code, as we only have two concrete fixit_hint
subclasses to deal with, rather than three.

The patch also fixes some problems in diagnostic-show-locus.c for
situations where a replacement fix-it has a different range to the
range of the diagnostic, by unifying the drawing of the two kinds of
fixits.  For example, this:

  foo = bar.field;
      ^
            m_field

becomes:

  foo = bar.field;
      ^
            -----
            m_field

showing the range to be replaced.

gcc/ChangeLog:
	* diagnostic-show-locus.c
	(layout::annotation_line_showed_range_p): New method.
	(layout::print_any_fixits): Remove case fixit_hint::REMOVE.
	Reimplement case fixit_hint::REPLACE to cover removals, and
	replacements where the range of the replacement isn't one
	of the ranges in the rich_location.
	(test_one_liner_fixit_replace): Likewise.
	(selftest::test_one_liner_fixit_replace_non_equal_range): New
	function.
	(selftest::test_one_liner_fixit_replace_equal_secondary_range):
	New function.
	(selftest::test_diagnostic_show_locus_one_liner): Call the new
	functions.
	* diagnostic.c (print_parseable_fixits): Remove case
	fixit_hint::REMOVE.

libcpp/ChangeLog:
	* include/line-map.h (fixit_hint::kind): Delete REPLACE.
	(class fixit_remove): Delete.
	* line-map.c (rich_location::add_fixit_remove): Reimplement
	by calling add_fixit_replace with an empty string.
	(fixit_remove::fixit_remove): Delete.
	(fixit_remove::affects_line_p): Delete.

From-SVN: r239632

3 files changed, 122 insertions, 24 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6593300..02c85f8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,21 @@
+2016-08-19  David Malcolm  <dmalcolm@redhat.com>
+
+	* diagnostic-show-locus.c
+	(layout::annotation_line_showed_range_p): New method.
+	(layout::print_any_fixits): Remove case fixit_hint::REMOVE.
+	Reimplement case fixit_hint::REPLACE to cover removals, and
+	replacements where the range of the replacement isn't one
+	of the ranges in the rich_location.
+	(test_one_liner_fixit_replace): Likewise.
+	(selftest::test_one_liner_fixit_replace_non_equal_range): New
+	function.
+	(selftest::test_one_liner_fixit_replace_equal_secondary_range):
+	New function.
+	(selftest::test_diagnostic_show_locus_one_liner): Call the new
+	functions.
+	* diagnostic.c (print_parseable_fixits): Remove case
+	fixit_hint::REMOVE.
+
 2016-08-19  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/77270
diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-locus.c
index 4498f7c..32b1078 100644
--- a/gcc/diagnostic-show-locus.c
+++ b/gcc/diagnostic-show-locus.c
@@ -199,6 +199,8 @@ class layout
 
   bool print_source_line (int row, line_bounds *lbounds_out);
   void print_annotation_line (int row, const line_bounds lbounds);
+  bool annotation_line_showed_range_p (int line, int start_column,
+				       int finish_column) const;
   void print_any_fixits (int row, const rich_location *richloc);
 
   void show_ruler (int max_column) const;
@@ -1053,6 +1055,26 @@ layout::print_annotation_line (int row, const line_bounds lbounds)
   print_newline ();
 }
 
+/* Subroutine of layout::print_any_fixits.
+
+   Determine if the annotation line printed for LINE contained
+   the exact range from START_COLUMN to FINISH_COLUMN.  */
+
+bool
+layout::annotation_line_showed_range_p (int line, int start_column,
+					int finish_column) const
+{
+  layout_range *range;
+  int i;
+  FOR_EACH_VEC_ELT (m_layout_ranges, i, range)
+    if (range->m_start.m_line == line
+	&& range->m_start.m_column == start_column
+	&& range->m_finish.m_line == line
+	&& range->m_finish.m_column == finish_column)
+      return true;
+  return false;
+}
+
 /* If there are any fixit hints on source line ROW within RICHLOC, print them.
    They are printed in order, attempting to combine them onto lines, but
    starting new lines if necessary.  */
@@ -1083,33 +1105,39 @@ layout::print_any_fixits (int row, const rich_location *richloc)
 	      }
 	      break;
 
-	    case fixit_hint::REMOVE:
+	    case fixit_hint::REPLACE:
 	      {
-		fixit_remove *remove = static_cast <fixit_remove *> (hint);
-		/* This assumes the removal just affects one line.  */
-		source_range src_range = remove->get_range ();
+		fixit_replace *replace = static_cast <fixit_replace *> (hint);
+		source_range src_range = replace->get_range ();
+		int line = LOCATION_LINE (src_range.m_start);
 		int start_column = LOCATION_COLUMN (src_range.m_start);
 		int finish_column = LOCATION_COLUMN (src_range.m_finish);
-		move_to_column (&column, start_column);
-		for (int column = start_column; column <= finish_column; column++)
+
+		/* If the range of the replacement wasn't printed in the
+		   annotation line, then print an extra underline to
+		   indicate exactly what is being replaced.
+		   Always show it for removals.  */
+		if (!annotation_line_showed_range_p (line, start_column,
+						     finish_column)
+		    || replace->get_length () == 0)
 		  {
+		    move_to_column (&column, start_column);
 		    m_colorizer.set_fixit_hint ();
-		    pp_character (m_pp, '-');
+		    for (; column <= finish_column; column++)
+		      pp_character (m_pp, '-');
 		    m_colorizer.set_normal_text ();
 		  }
-	      }
-	      break;
-
-	    case fixit_hint::REPLACE:
-	      {
-		fixit_replace *replace = static_cast <fixit_replace *> (hint);
-		int start_column
-		  = LOCATION_COLUMN (replace->get_range ().m_start);
-		move_to_column (&column, start_column);
-		m_colorizer.set_fixit_hint ();
-		pp_string (m_pp, replace->get_string ());
-		m_colorizer.set_normal_text ();
-		column += replace->get_length ();
+		/* Print the replacement text.  REPLACE also covers
+		   removals, so only do this extra work (potentially starting
+		   a new line) if we have actual replacement text.  */
+		if (replace->get_length () > 0)
+		  {
+		    move_to_column (&column, start_column);
+		    m_colorizer.set_fixit_hint ();
+		    pp_string (m_pp, replace->get_string ());
+		    m_colorizer.set_normal_text ();
+		    column += replace->get_length ();
+		  }
 	      }
 	      break;
 
@@ -1502,6 +1530,60 @@ test_one_liner_fixit_replace ()
 		pp_formatted_text (dc.printer));
 }
 
+/* Replace fix-it hint: replacing "field" with "m_field",
+   but where the caret was elsewhere.  */
+
+static void
+test_one_liner_fixit_replace_non_equal_range ()
+{
+  test_diagnostic_context dc;
+  location_t equals = linemap_position_for_column (line_table, 5);
+  location_t start = linemap_position_for_column (line_table, 11);
+  location_t finish = linemap_position_for_column (line_table, 15);
+  rich_location richloc (line_table, equals);
+  source_range range;
+  range.m_start = start;
+  range.m_finish = finish;
+  richloc.add_fixit_replace (range, "m_field");
+  diagnostic_show_locus (&dc, &richloc, DK_ERROR);
+  /* The replacement range is not indicated in the annotation line, so
+     it should be indicated via an additional underline.  */
+  ASSERT_STREQ ("\n"
+		" foo = bar.field;\n"
+		"     ^\n"
+		"           -----\n"
+		"           m_field\n",
+		pp_formatted_text (dc.printer));
+}
+
+/* Replace fix-it hint: replacing "field" with "m_field",
+   where the caret was elsewhere, but where a secondary range
+   exactly covers "field".  */
+
+static void
+test_one_liner_fixit_replace_equal_secondary_range ()
+{
+  test_diagnostic_context dc;
+  location_t equals = linemap_position_for_column (line_table, 5);
+  location_t start = linemap_position_for_column (line_table, 11);
+  location_t finish = linemap_position_for_column (line_table, 15);
+  rich_location richloc (line_table, equals);
+  location_t field = make_location (start, start, finish);
+  richloc.add_range (field, false);
+  source_range range;
+  range.m_start = start;
+  range.m_finish = finish;
+  richloc.add_fixit_replace (range, "m_field");
+  diagnostic_show_locus (&dc, &richloc, DK_ERROR);
+  /* The replacement range is indicated in the annotation line,
+     so it shouldn't be indicated via an additional underline.  */
+  ASSERT_STREQ ("\n"
+		" foo = bar.field;\n"
+		"     ^     ~~~~~\n"
+		"           m_field\n",
+		pp_formatted_text (dc.printer));
+}
+
 /* Run the various one-liner tests.  */
 
 static void
@@ -1532,6 +1614,8 @@ test_diagnostic_show_locus_one_liner (const line_table_case &case_)
   test_one_liner_fixit_insert ();
   test_one_liner_fixit_remove ();
   test_one_liner_fixit_replace ();
+  test_one_liner_fixit_replace_non_equal_range ();
+  test_one_liner_fixit_replace_equal_secondary_range ();
 }
 
 /* Run all of the selftests within this file.  */
diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
index fec48c4..b47da38 100644
--- a/gcc/diagnostic.c
+++ b/gcc/diagnostic.c
@@ -758,10 +758,6 @@ print_parseable_fixits (pretty_printer *pp, rich_location *richloc)
 	    }
 	    break;
 
-	  case fixit_hint::REMOVE:
-	    print_escaped_string (pp, "");
-	    break;
-
 	  case fixit_hint::REPLACE:
 	    {
 	      const fixit_replace *replace