PR preprocessor/69177 and PR c++/68819: libcpp fallbacks and -Wmisleading-indentation

gcc/c-family/ChangeLog:
	PR c++/68819
	* c-indentation.c (get_visual_column): Add location_t param.
	Handle the column number being zero by effectively disabling the
	warning, with an "inform".
	(should_warn_for_misleading_indentation): Add location_t argument
	for all uses of get_visual_column.

gcc/testsuite/ChangeLog:
	PR c++/68819
	PR preprocessor/69177
	* gcc.dg/plugin/location-overflow-test-1.c: New test case.
	* gcc.dg/plugin/location-overflow-test-2.c: New test case.
	* gcc.dg/plugin/location_overflow_plugin.c: New test plugin.
	* gcc.dg/plugin/plugin.exp (plugin_test_list): Add the above.

libcpp/ChangeLog:
	PR preprocessor/69177
	* line-map.c (LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES): New
	constant.
	(LINE_MAP_MAX_LOCATION_WITH_COLS): Add note about unit tests
	to comment.
	(can_be_stored_compactly_p): Reduce threshold from
	LINE_MAP_MAX_LOCATION_WITH_COLS to
	LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES.
	(get_combined_adhoc_loc): Likewise.
	(get_range_from_loc): Likewise.
	(linemap_line_start): Ensure that a new ordinary map is created
	when transitioning from range-packing being enabled to disabled,
	at the LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES threshold.  Set
	range_bits to 0 for new ordinary maps when beyond this limit.
	Prevent the "increase the column bits of a freshly created map"
	optimization if the range bits has reduced.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@232379 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 35 insertions, 5 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index d8282d9de47..e3b9654c85b 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,12 @@
+2016-01-14  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c++/68819
+	* c-indentation.c (get_visual_column): Add location_t param.
+	Handle the column number being zero by effectively disabling the
+	warning, with an "inform".
+	(should_warn_for_misleading_indentation): Add location_t argument
+	for all uses of get_visual_column.
+
 2016-01-10  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	PR c++/69029
diff --git a/gcc/c-family/c-indentation.c b/gcc/c-family/c-indentation.c
index cd9637dc3fe..521f9924fd0 100644
--- a/gcc/c-family/c-indentation.c
+++ b/gcc/c-family/c-indentation.c
@@ -36,10 +36,30 @@ extern cpp_options *cpp_opts;
    on the line.  */
 
 static bool
-get_visual_column (expanded_location exploc,
+get_visual_column (expanded_location exploc, location_t loc,
 		   unsigned int *out,
 		   unsigned int *first_nws)
 {
+  /* PR c++/68819: if the column number is zero, we presumably
+     had a location_t > LINE_MAP_MAX_LOCATION_WITH_COLS, and so
+     we have no column information.
+     Act as if no conversion was possible, triggering the
+     error-handling path in the caller.  */
+  if (!exploc.column)
+    {
+      static bool issued_note = false;
+      if (!issued_note)
+	{
+	  /* Notify the user the first time this happens.  */
+	  issued_note = true;
+	  inform (loc,
+		  "-Wmisleading-indentation is disabled from this point"
+		  " onwards, since column-tracking was disabled due to"
+		  " the size of the code/headers");
+	}
+      return false;
+    }
+
   int line_len;
   const char *line = location_get_source_line (exploc.file, exploc.line,
 					       &line_len);
@@ -297,7 +317,7 @@ should_warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
 	  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,
+	  if (!get_visual_column (guard_exploc, guard_loc,
 				  &guard_vis_column,
 				  &guard_line_first_nws))
 	    return false;
@@ -357,14 +377,15 @@ should_warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
 	 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 (!get_visual_column (next_stmt_exploc, &next_stmt_vis_column,
+      if (!get_visual_column (next_stmt_exploc, next_stmt_loc,
+			      &next_stmt_vis_column,
 			      &next_stmt_line_first_nws))
 	return false;
-      if (!get_visual_column (body_exploc,
+      if (!get_visual_column (body_exploc, body_loc,
 			      &body_vis_column,
 			      &body_line_first_nws))
 	return false;
-      if (!get_visual_column (guard_exploc,
+      if (!get_visual_column (guard_exploc, guard_loc,
 			      &guard_vis_column,
 			      &guard_line_first_nws))
 	return false;