Implement -Wmisleading-indentation

gcc/ChangeLog:
	* doc/invoke.texi (Warning Options): Add -Wmisleading-indentation.
	(-Wmisleading-indentation): New option.
	* Makefile.in (C_COMMON_OBJS): Add c-family/c-indentation.o.

gcc/c-family/ChangeLog:
	* c-common.h (warn_for_misleading_indentation): New prototype.
	* c-indentation.c: New file.
	* c.opt (Wmisleading-indentation): New option.

gcc/c/ChangeLog:
	* c-parser.c (c_parser_if_body): Add param "if_loc", use it
	to add a call to warn_for_misleading_indentation.
	(c_parser_else_body): Likewise, adding param "else_loc".
	(c_parser_if_statement): Check for misleading indentation.
	(c_parser_while_statement): Likewise.
	(c_parser_for_statement): Likewise.

gcc/cp/ChangeLog:
	* parser.c (cp_parser_selection_statement): Add location and
	guard_kind arguments to calls to
	cp_parser_implicitly_scoped_statement.
	(cp_parser_iteration_statement): Likewise for calls to
	cp_parser_already_scoped_statement.
	(cp_parser_implicitly_scoped_statement): Add "guard_loc" and
	"guard_kind" params; use them to warn for misleading
	indentation.
	(cp_parser_already_scoped_statement): Likewise.

gcc/testsuite/ChangeLog:
	* c-c++-common/Wmisleading-indentation.c: New testcase.
	* c-c++-common/Wmisleading-indentation-2.c: New testcase.
	* c-c++-common/Wmisleading-indentation-2.md: New file.

libcpp/ChangeLog:
	* directives.c (do_line): Set seen_line_directive on line_table.
	(do_linemarker): Likewise.
	* include/line-map.h (struct line_maps): Add new field
	"seen_line_directive".

From-SVN: r223098

1 files changed, 43 insertions, 8 deletions

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index bf0e4c57..36438d0 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -5185,7 +5185,7 @@ c_parser_c99_block_statement (c_parser *parser)
    parser->in_if_block.  */
 
 static tree
-c_parser_if_body (c_parser *parser, bool *if_p)
+c_parser_if_body (c_parser *parser, bool *if_p, location_t if_loc)
 {
   tree block = c_begin_compound_stmt (flag_isoc99);
   location_t body_loc = c_parser_peek_token (parser)->location;
@@ -5203,7 +5203,15 @@ c_parser_if_body (c_parser *parser, bool *if_p)
   else if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
     add_stmt (c_parser_compound_statement (parser));
   else
-    c_parser_statement_after_labels (parser);
+    {
+      c_parser_statement_after_labels (parser);
+      if (!c_parser_next_token_is_keyword (parser, RID_ELSE))
+	warn_for_misleading_indentation (if_loc, body_loc,
+					 c_parser_peek_token (parser)->location,
+					 c_parser_peek_token (parser)->type,
+					 "if");
+    }
+
   return c_end_compound_stmt (body_loc, block, flag_isoc99);
 }
 
@@ -5212,9 +5220,9 @@ c_parser_if_body (c_parser *parser, bool *if_p)
    specially for the sake of -Wempty-body warnings.  */
 
 static tree
-c_parser_else_body (c_parser *parser)
+c_parser_else_body (c_parser *parser, location_t else_loc)
 {
-  location_t else_loc = c_parser_peek_token (parser)->location;
+  location_t body_loc = c_parser_peek_token (parser)->location;
   tree block = c_begin_compound_stmt (flag_isoc99);
   c_parser_all_labels (parser);
   if (c_parser_next_token_is (parser, CPP_SEMICOLON))
@@ -5227,8 +5235,14 @@ c_parser_else_body (c_parser *parser)
       c_parser_consume_token (parser);
     }
   else
-    c_parser_statement_after_labels (parser);
-  return c_end_compound_stmt (else_loc, block, flag_isoc99);
+    {
+      c_parser_statement_after_labels (parser);
+      warn_for_misleading_indentation (else_loc, body_loc,
+				       c_parser_peek_token (parser)->location,
+				       c_parser_peek_token (parser)->type,
+				       "else");
+    }
+  return c_end_compound_stmt (body_loc, block, flag_isoc99);
 }
 
 /* Parse an if statement (C90 6.6.4, C99 6.8.4).
@@ -5250,6 +5264,7 @@ c_parser_if_statement (c_parser *parser)
   tree if_stmt;
 
   gcc_assert (c_parser_next_token_is_keyword (parser, RID_IF));
+  location_t if_loc = c_parser_peek_token (parser)->location;
   c_parser_consume_token (parser);
   block = c_begin_compound_stmt (flag_isoc99);
   loc = c_parser_peek_token (parser)->location;
@@ -5261,12 +5276,13 @@ c_parser_if_statement (c_parser *parser)
     }
   in_if_block = parser->in_if_block;
   parser->in_if_block = true;
-  first_body = c_parser_if_body (parser, &first_if);
+  first_body = c_parser_if_body (parser, &first_if, if_loc);
   parser->in_if_block = in_if_block;
   if (c_parser_next_token_is_keyword (parser, RID_ELSE))
     {
+      location_t else_loc = c_parser_peek_token (parser)->location;
       c_parser_consume_token (parser);
-      second_body = c_parser_else_body (parser);
+      second_body = c_parser_else_body (parser, else_loc);
     }
   else
     second_body = NULL_TREE;
@@ -5346,6 +5362,7 @@ c_parser_while_statement (c_parser *parser, bool ivdep)
   tree block, cond, body, save_break, save_cont;
   location_t loc;
   gcc_assert (c_parser_next_token_is_keyword (parser, RID_WHILE));
+  location_t while_loc = c_parser_peek_token (parser)->location;
   c_parser_consume_token (parser);
   block = c_begin_compound_stmt (flag_isoc99);
   loc = c_parser_peek_token (parser)->location;
@@ -5362,7 +5379,16 @@ c_parser_while_statement (c_parser *parser, bool ivdep)
   c_break_label = NULL_TREE;
   save_cont = c_cont_label;
   c_cont_label = NULL_TREE;
+
+  location_t body_loc = UNKNOWN_LOCATION;
+  if (c_parser_peek_token (parser)->type != CPP_OPEN_BRACE)
+    body_loc = c_parser_peek_token (parser)->location;
   body = c_parser_c99_block_statement (parser);
+  warn_for_misleading_indentation (while_loc, body_loc,
+				   c_parser_peek_token (parser)->location,
+				   c_parser_peek_token (parser)->type,
+				   "while");
+
   c_finish_loop (loc, cond, NULL, body, c_break_label, c_cont_label, true);
   add_stmt (c_end_compound_stmt (loc, block, flag_isoc99));
   c_break_label = save_break;
@@ -5640,7 +5666,16 @@ c_parser_for_statement (c_parser *parser, bool ivdep)
   c_break_label = NULL_TREE;
   save_cont = c_cont_label;
   c_cont_label = NULL_TREE;
+
+  location_t body_loc = UNKNOWN_LOCATION;
+  if (c_parser_peek_token (parser)->type != CPP_OPEN_BRACE)
+    body_loc = c_parser_peek_token (parser)->location;
   body = c_parser_c99_block_statement (parser);
+  warn_for_misleading_indentation (for_loc, body_loc,
+				   c_parser_peek_token (parser)->location,
+				   c_parser_peek_token (parser)->type,
+				   "for");
+
   if (is_foreach_statement)
     objc_finish_foreach_loop (loc, object_expression, collection_expression, body, c_break_label, c_cont_label);
   else