Remove is_first_nonwhitespace_on_line(), instead improve get_visual_column()

gcc/c-family/ChangeLog:

	* c-indentation.c (get_visual_column): Add parameter first_nws,
	use it.  Update comment documenting the function.
	(is_first_nonwhitespace_on_line): Remove.
	(should_warn_for_misleading_indentation): Replace usage of
	of is_first_nonwhitespace_on_line with get_visual_column.

From-SVN: r226478

2 files changed, 32 insertions, 29 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 8dfc81b..bb74de9 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,5 +1,13 @@
 2015-08-02  Patrick Palka  <ppalka@gcc.gnu.org>
 
+	* c-indentation.c (get_visual_column): Add parameter first_nws,
+	use it.  Update comment documenting the function.
+	(is_first_nonwhitespace_on_line): Remove.
+	(should_warn_for_misleading_indentation): Replace usage of
+	of is_first_nonwhitespace_on_line with get_visual_column.
+
+2015-08-02  Patrick Palka  <ppalka@gcc.gnu.org>
+
 	* c-indentation.h (struct token_indent_info): Define.
 	(get_token_indent_info): Define.
 	(warn_for_misleading_information): Declare.
diff --git a/gcc/c-family/c-indentation.c b/gcc/c-family/c-indentation.c
index 544b0d4..cdf0372 100644
--- a/gcc/c-family/c-indentation.c
+++ b/gcc/c-family/c-indentation.c
@@ -33,11 +33,16 @@ extern cpp_options *cpp_opts;
 /* Convert libcpp's notion of a column (a 1-based char count) to
    the "visual column" (0-based column, respecting tabs), by reading the
    relevant line.
+
    Returns true if a conversion was possible, writing the result to OUT,
-   otherwise returns false.  */
+   otherwise returns false.  If FIRST_NWS is not NULL, then write to it
+   the visual column corresponding to the first non-whitespace character
+   on the line.  */
 
 static bool
-get_visual_column (expanded_location exploc, unsigned int *out)
+get_visual_column (expanded_location exploc,
+		   unsigned int *out,
+		   unsigned int *first_nws = NULL)
 {
   int line_len;
   const char *line = location_get_source_line (exploc, &line_len);
@@ -47,6 +52,13 @@ get_visual_column (expanded_location exploc, unsigned int *out)
   for (int i = 1; i < exploc.column; i++)
     {
       unsigned char ch = line[i - 1];
+
+      if (first_nws != NULL && !ISSPACE (ch))
+	{
+	  *first_nws = vis_column;
+	  first_nws = NULL;
+	}
+
       if (ch == '\t')
        {
 	 /* Round up to nearest tab stop. */
@@ -57,33 +69,10 @@ get_visual_column (expanded_location exploc, unsigned int *out)
        vis_column++;
     }
 
-  *out = vis_column;
-  return true;
-}
-
-/* Is the token at LOC the first non-whitespace on its line?
-   Helper function for should_warn_for_misleading_indentation.  */
+  if (first_nws != NULL)
+    *first_nws = vis_column;
 
-static bool
-is_first_nonwhitespace_on_line (expanded_location exploc)
-{
-  int line_len;
-  const char *line = location_get_source_line (exploc, &line_len);
-
-   /* If we can't determine it, return false so that we don't issue a
-      warning.  This is sometimes the case for input files
-      containing #line directives, and these are often for autogenerated
-      sources (e.g. from .md files), where it's not clear that it's
-      meaningful to look at indentation.  */
-  if (!line)
-    return false;
-
-  for (int i = 1; i < exploc.column; i++)
-    {
-      unsigned char ch = line[i - 1];
-      if (!ISSPACE (ch))
-	return false;
-    }
+  *out = vis_column;
   return true;
 }
 
@@ -279,9 +268,15 @@ should_warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
 	  /* They're all on the same line.  */
 	  gcc_assert (guard_exploc.file == next_stmt_exploc.file);
 	  gcc_assert (guard_exploc.line == next_stmt_exploc.line);
+	  unsigned int guard_vis_column;
+	  unsigned int guard_line_first_nws;
+	  if (!get_visual_column (guard_exploc,
+				  &guard_vis_column,
+				  &guard_line_first_nws))
+	    return false;
 	  /* Heuristic: only warn if the guard is the first thing
 	     on its line.  */
-	  if (is_first_nonwhitespace_on_line (guard_exploc))
+	  if (guard_vis_column == guard_line_first_nws)
 	    return true;
 	}
     }