Eliminate fixit_hint class hierarchy

The original implementation of fix-it hints (r230674) had an abstract
base class "fixit_hint" and three subclasses, representing
each of insertions, replacements, and deletions.

Having multiple classes for fix-it hints was a nuisance, as it required
per-class logic everywhere that the hints were handled.

In r239632 I eliminated the deletion subclass in favor of replacement
with the empty string (two subclasses are easier than three).

This patch eliminates the class hierarchy altogether by implementing
insertion in terms of replacement, by representing replacements via
a half-open interval (so that for an insertion, start == next location,
and we're effectively replacing an empty range at the insertion point
with the new string).

This greatly simplifies the code for handling fix-it hints; for example
it allows removal of a parallel class hierarchy of line_event within
edit-context.c.

It also improves consolidation of hints: we can now consolidate
insertions at the same location, affecting a couple of tests
(selftest::test_one_liner_many_fixits and
gcc.dg/Wmissing-braces-fixits.c).

gcc/ChangeLog:
	* diagnostic-show-locus.c (layout::get_expanded_location): Rewrite
	to use new fixit_hint representation, using the "replace" logic.
	(get_line_span_for_fixit_hint): Likewise.
	(layout::print_any_fixits): Likewise.
	(selftest::test_one_liner_many_fixits): Rename to...
	(selftest::test_one_liner_many_fixits_1): ...this, and update
	comment and expected output to reflect that the multiple fix-it
	hints are now consolidated into one insertion.
	(selftest::test_one_liner_many_fixits_2): New test.
	(selftest::test_diagnostic_show_locus_one_liner): Update for
	above.
	(selftest::test_fixit_consolidation): Update for fix-it API
	change.
	* diagnostic.c (print_parseable_fixits): Likewise.
	* edit-context.c (edited_line::m_line_events): Convert from
	auto_vec <line_event *> to auto_vec <line_event>.
	(class line_event): Convert from abstract base class to a concrete
	class, taking over the role of replace_event.
	(class insert_event): Delete.
	(class replace_event): Rename to class line_event.  Convert to
	half-open range.
	(edit_context::add_fixits): Reimplement.
	(edit_context::apply_insert): Delete.
	(edit_context::apply_replace): Rename to...
	(edit_context::apply_fixit): ...this.  Convert to half-open range.
	(edited_file::apply_insert): Delete.
	(edited_file::apply_replace): Rename to...
	(edited_file::apply_fixit): ...this.
	(edited_line::~edited_line): Drop deletion of events.
	(edited_line::apply_insert): Delete.
	(edited_line::apply_replace): Rename to...
	(edited_line::apply_fixit): ...this.  Convert to half-open range.
	Update for change to type of m_line_events.
	* edit-context.h (edit_context::apply_insert): Delete.
	(edit_context::apply_replace): Rename to...
	(edit_context::apply_fixit): ...this.

gcc/testsuite/ChangeLog:
	* gcc.dg/Wmissing-braces-fixits.c: Update expected output to
	reflect insertion fix-it hints at the same location now being
	consolidated.

libcpp/ChangeLog:
	* include/line-map.h (source_range::intersects_line_p): Delete.
	(rich_location::add_fixit): Delete.
	(rich_location::maybe_add_fixit): New method.
	(class fixit_hint): Reimplement in terms of...
	(class fixit_replace): ...this.
	(class fixit_insert): Delete.
	* line-map.c (linemap_position_for_loc_and_offset): Drop overzealous
	linemap_assert_fails.
	(source_range::intersects_line_p): Rename to...
	(fixit_hint::affects_line_p): New function.
	(rich_location::add_fixit_insert_before): Reimplement in terms of
	maybe_add_fixit, moving validation there.
	(rich_location::add_fixit_insert_after): Likewise.
	(column_before_p): Delete.
	(rich_location::add_fixit_replace): Reimplement in terms of
	maybe_add_fixit, moving validation there.  Convert closed input range
	to half-open range.
	(rich_location::add_fixit): Delete.
	(rich_location::maybe_add_fixit): New function.
	(fixit_insert::fixit_insert): Delete.
	(fixit_insert::~fixit_insert): Delete.
	(fixit_insert::affects_line_p): Delete.
	(fixit_insert::maybe_append_replace): Delete.
	(fixit_replace::fixit_replace): Rename to...
	(fixit_hint::fixit_hint): ...this, rewriting as necessary.
	(fixit_replace::~fixit_replace): Delete.
	(fixit_replace::affects_line_p): Delete.
	(fixit_replace::maybe_append_replace): Rename to...
	(fixit_hint::maybe_append): ...this, rewriting as necessary.

From-SVN: r247445

1 files changed, 54 insertions, 194 deletions

diff --git a/gcc/edit-context.c b/gcc/edit-context.c
index db8a5dc..bea8a8a 100644
--- a/gcc/edit-context.c
+++ b/gcc/edit-context.c
@@ -45,8 +45,6 @@ class edit_context;
 class edited_file;
 class edited_line;
 class line_event;
-  class insert_event;
-  class replace_event;
 
 /* A struct to hold the params of a print_diff call.  */
 
@@ -71,11 +69,10 @@ class edited_file
   const char *get_filename () const { return m_filename; }
   char *get_content ();
 
-  bool apply_insert (int line, int column, const char *str, int len);
-  bool apply_replace (int line, int start_column,
-		      int finish_column,
-		      const char *replacement_str,
-		      int replacement_len);
+  bool apply_fixit (int line, int start_column,
+		    int next_column,
+		    const char *replacement_str,
+		    int replacement_len);
   int get_effective_column (int line, int column);
 
   static int call_print_diff (const char *, edited_file *file,
@@ -119,11 +116,10 @@ class edited_line
   int get_len () const { return m_len; }
 
   int get_effective_column (int orig_column) const;
-  bool apply_insert (int column, const char *str, int len);
-  bool apply_replace (int start_column,
-		      int finish_column,
-		      const char *replacement_str,
-		      int replacement_len);
+  bool apply_fixit (int start_column,
+		    int next_column,
+		    const char *replacement_str,
+		    int replacement_len);
 
  private:
   void ensure_capacity (int len);
@@ -134,55 +130,23 @@ class edited_line
   char *m_content;
   int m_len;
   int m_alloc_sz;
-  auto_vec <line_event *> m_line_events;
+  auto_vec <line_event> m_line_events;
 };
 
-/* Abstract base class for representing events that have occurred
-   on one line of one file.  */
-
-class line_event
-{
- public:
-  virtual ~line_event () {}
-  virtual int get_effective_column (int orig_column) const = 0;
-};
-
-/* Concrete subclass of line_event: an insertion of some text
-   at some column on the line.
+/* Class for representing edit events that have occurred on one line of
+   one file: the replacement of some text betweeen some columns
+   on the line.
 
    Subsequent events will need their columns adjusting if they're
-   are on this line and their column is >= the insertion point.  */
+   are on this line and their column is >= the start point.  */
 
-class insert_event : public line_event
-{
- public:
-  insert_event (int column, int len) : m_column (column), m_len (len) {}
-  int get_effective_column (int orig_column) const FINAL OVERRIDE
-  {
-    if (orig_column >= m_column)
-      return orig_column + m_len;
-    else
-      return orig_column;
-  }
-
- private:
-  int m_column;
-  int m_len;
-};
-
-/* Concrete subclass of line_event: the replacement of some text
-   betweeen some columns on the line.
-
-   Subsequent events will need their columns adjusting if they're
-   are on this line and their column is >= the finish point.  */
-
-class replace_event : public line_event
+class line_event
 {
  public:
-  replace_event (int start, int finish, int len) : m_start (start),
-    m_finish (finish), m_delta (len - (finish + 1 - start)) {}
+  line_event (int start, int next, int len) : m_start (start),
+    m_next (next), m_delta (len - (next - start)) {}
 
-  int get_effective_column (int orig_column) const FINAL OVERRIDE
+  int get_effective_column (int orig_column) const
   {
     if (orig_column >= m_start)
       return orig_column += m_delta;
@@ -192,7 +156,7 @@ class replace_event : public line_event
 
  private:
   int m_start;
-  int m_finish;
+  int m_next;
   int m_delta;
 };
 
@@ -221,27 +185,8 @@ edit_context::add_fixits (rich_location *richloc)
   for (unsigned i = 0; i < richloc->get_num_fixit_hints (); i++)
     {
       const fixit_hint *hint = richloc->get_fixit_hint (i);
-      switch (hint->get_kind ())
-	{
-	case fixit_hint::INSERT:
-	  if (!apply_insert ((const fixit_insert *)hint))
-	    {
-	      /* Failure.  */
-	      m_valid = false;
-	      return;
-	    }
-	  break;
-	case fixit_hint::REPLACE:
-	  if (!apply_replace ((const fixit_replace *)hint))
-	    {
-	      /* Failure.  */
-	      m_valid = false;
-	      return;
-	    }
-	  break;
-	default:
-	  gcc_unreachable ();
-	}
+      if (!apply_fixit (hint))
+	m_valid = false;
     }
 }
 
@@ -302,45 +247,25 @@ edit_context::print_diff (pretty_printer *pp, bool show_filenames)
    applied, or false otherwise.  */
 
 bool
-edit_context::apply_insert (const fixit_insert *insert)
-{
-  expanded_location exploc = expand_location (insert->get_location ());
-
-  if (exploc.column == 0)
-    return false;
-
-  edited_file &file = get_or_insert_file (exploc.file);
-  if (!m_valid)
-    return false;
-  return file.apply_insert (exploc.line, exploc.column, insert->get_string (),
-			    insert->get_length ());
-}
-
-/* Attempt to apply the given fixit.  Return true if it can be
-   applied, or false otherwise.  */
-
-bool
-edit_context::apply_replace (const fixit_replace *replace)
+edit_context::apply_fixit (const fixit_hint *hint)
 {
-  source_range range = replace->get_range ();
-
-  expanded_location start = expand_location (range.m_start);
-  expanded_location finish = expand_location (range.m_finish);
-  if (start.file != finish.file)
+  expanded_location start = expand_location (hint->get_start_loc ());
+  expanded_location next_loc = expand_location (hint->get_next_loc ());
+  if (start.file != next_loc.file)
     return false;
-  if (start.line != finish.line)
+  if (start.line != next_loc.line)
     return false;
   if (start.column == 0)
     return false;
-  if (finish.column == 0)
+  if (next_loc.column == 0)
     return false;
 
   edited_file &file = get_or_insert_file (start.file);
   if (!m_valid)
     return false;
-  return file.apply_replace (start.line, start.column, finish.column,
-			     replace->get_string (),
-			     replace->get_length ());
+  return file.apply_fixit (start.line, start.column, next_loc.column,
+			   hint->get_string (),
+			   hint->get_length ());
 }
 
 /* Locate the edited_file * for FILENAME, if any
@@ -409,37 +334,21 @@ edited_file::get_content ()
   return xstrdup (pp_formatted_text (&pp));
 }
 
-/* Attempt to insert the string INSERT_STR with length INSERT_LEN
-   at LINE and COLUMN, updating the in-memory copy of the line, and
-   the record of edits to the line.  */
-
-bool
-edited_file::apply_insert (int line, int column,
-			   const char *insert_str,
-			   int insert_len)
-{
-  edited_line *el = get_or_insert_line (line);
-  if (!el)
-    return false;
-  return el->apply_insert (column, insert_str, insert_len);
-}
-
-/* Attempt to replace columns START_COLUMN through FINISH_COLUMN of LINE
-   with the string REPLACEMENT_STR of length REPLACEMENT_LEN,
+/* Attempt to replace columns START_COLUMN up to but not including NEXT_COLUMN
+   of LINE with the string REPLACEMENT_STR of length REPLACEMENT_LEN,
    updating the in-memory copy of the line, and the record of edits to
    the line.  */
 
 bool
-edited_file::apply_replace (int line, int start_column,
-			    int finish_column,
-			    const char *replacement_str,
-			    int replacement_len)
+edited_file::apply_fixit (int line, int start_column, int next_column,
+			  const char *replacement_str,
+			  int replacement_len)
 {
   edited_line *el = get_or_insert_line (line);
   if (!el)
     return false;
-  return el->apply_replace (start_column, finish_column, replacement_str,
-			    replacement_len);
+  return el->apply_fixit (start_column, next_column, replacement_str,
+			  replacement_len);
 }
 
 /* Given line LINE, map from COLUMN in the input file to its current
@@ -698,11 +607,6 @@ edited_line::edited_line (const char *filename, int line_num)
 edited_line::~edited_line ()
 {
   free (m_content);
-
-  int i;
-  line_event *event;
-  FOR_EACH_VEC_ELT (m_line_events, i, event)
-    delete event;
 }
 
 /* A callback for deleting edited_line *, for use as a
@@ -727,85 +631,41 @@ edited_line::get_effective_column (int orig_column) const
   return orig_column;
 }
 
-/* Attempt to insert the string INSERT_STR with length INSERT_LEN at COLUMN
-   of this line, updating the in-memory copy of the line, and the record
-   of edits to it.
-   Return true if successful; false if an error occurred.  */
-
-bool
-edited_line::apply_insert (int column, const char *insert_str,
-			   int insert_len)
-{
-  column = get_effective_column (column);
-
-  int start_offset = column - 1;
-  gcc_assert (start_offset >= 0);
-  if (start_offset > m_len)
-    return false;
-
-  /* Ensure buffer is big enough.  */
-  size_t new_len = m_len + insert_len;
-  ensure_capacity (new_len);
-
-  char *suffix = m_content + start_offset;
-  gcc_assert (suffix <= m_content + m_len);
-  size_t len_suffix = (m_content + m_len) - suffix;
-
-  /* Move successor content into position.  They overlap, so use memmove.  */
-  memmove (m_content + start_offset + insert_len,
-	   suffix, len_suffix);
-
-  /* Replace target content.  They don't overlap, so use memcpy.  */
-  memcpy (m_content + start_offset,
-	  insert_str,
-	  insert_len);
-
-  m_len = new_len;
-
-  ensure_terminated ();
-
-  /* Record the insertion, so that future changes to the line can have
-     their column information adjusted accordingly.  */
-  m_line_events.safe_push (new insert_event (column, insert_len));
-
-  return true;
-}
-
-/* Attempt to replace columns START_COLUMN through FINISH_COLUMN of the line
-   with the string REPLACEMENT_STR of length REPLACEMENT_LEN,
-   updating the in-memory copy of the line, and the record of edits to
-   the line.
+/* Attempt to replace columns START_COLUMN up to but not including
+   NEXT_COLUMN of the line with the string REPLACEMENT_STR of
+   length REPLACEMENT_LEN, updating the in-memory copy of the line,
+   and the record of edits to the line.
    Return true if successful; false if an error occurred.  */
 
 bool
-edited_line::apply_replace (int start_column,
-			    int finish_column,
-			    const char *replacement_str,
-			    int replacement_len)
+edited_line::apply_fixit (int start_column,
+			  int next_column,
+			  const char *replacement_str,
+			  int replacement_len)
 {
   start_column = get_effective_column (start_column);
-  finish_column = get_effective_column (finish_column);
+  next_column = get_effective_column (next_column);
 
   int start_offset = start_column - 1;
-  int end_offset = finish_column - 1;
+  int next_offset = next_column - 1;
 
   gcc_assert (start_offset >= 0);
-  gcc_assert (end_offset >= 0);
+  gcc_assert (next_offset >= 0);
 
-  if (start_column > finish_column)
+  if (start_column > next_column)
     return false;
-  if (start_offset >= m_len)
+  if (start_offset >= (m_len + 1))
     return false;
-  if (end_offset >= m_len)
+  if (next_offset >= (m_len + 1))
     return false;
 
-  size_t victim_len = end_offset - start_offset + 1;
+  size_t victim_len = next_offset - start_offset;
 
   /* Ensure buffer is big enough.  */
   size_t new_len = m_len + replacement_len - victim_len;
   ensure_capacity (new_len);
 
-  char *suffix = m_content + end_offset + 1;
+  char *suffix = m_content + next_offset;
   gcc_assert (suffix <= m_content + m_len);
   size_t len_suffix = (m_content + m_len) - suffix;
 
@@ -824,8 +684,8 @@ edited_line::apply_replace (int start_column,
 
   /* Record the replacement, so that future changes to the line can have
      their column information adjusted accordingly.  */
-  m_line_events.safe_push (new replace_event (start_column, finish_column,
-					      replacement_len));
+  m_line_events.safe_push (line_event (start_column, next_column,
+				       replacement_len));
   return true;
 }