Refactor entry point to -Wmisleading-indentation

gcc/c-family/ChangeLog:

	* c-indentation.h (struct token_indent_info): Define.
	(get_token_indent_info): Define.
	(warn_for_misleading_information): Declare.
	* c-common.h (warn_for_misleading_information): Remove.
	* c-identation.c (warn_for_misleading_indentation):
	Change declaration to take three token_indent_infos.  Adjust
	accordingly.
	* c-identation.c (should_warn_for_misleading_indentation):
	Likewise.  Bail out early if the body is a compound statement.
	(guard_tinfo_to_string): Define.

gcc/c/ChangeLog:

	* c-parser.c (c_parser_if_body): Take token_indent_info
	argument. Call warn_for_misleading_indentation even when the
	body is a semicolon.  Extract token_indent_infos corresponding
	to the guard, body and next tokens.  Adjust call to
	warn_for_misleading_indentation accordingly.
	(c_parser_else_body): Likewise.
	(c_parser_if_statement): Likewise.
	(c_parser_while_statement): Likewise.
	(c_parser_for_statement): Likewise.

gcc/cp/ChangeLog:

	* parser.c (cp_parser_selection_statement): Move handling of
	semicolon body to ...
	(cp_parser_implicitly_scoped_statement): .. here.  Call
	warn_for_misleading_indentation even when the body is a
	semicolon.  Extract token_indent_infos corresponding to the
	guard, body and next tokens.  Adjust call to
	warn_for_misleading_indentation accordingly.  Take
	token_indent_info argument.
	(cp_parser_already_scoped_statement): Likewise.
	(cp_parser_selection_statement, cp_parser_iteration_statement):
	Extract a token_indent_info corresponding to the guard token.

From-SVN: r226477

4 files changed, 126 insertions, 25 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 9ab9551..8dfc81b 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,16 @@
+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.
+	* c-common.h (warn_for_misleading_information): Remove.
+	* c-identation.c (warn_for_misleading_indentation):
+	Change declaration to take three token_indent_infos.  Adjust
+	accordingly.
+	* c-identation.c (should_warn_for_misleading_indentation):
+	Likewise.  Bail out early if the body is a compound statement.
+	(guard_tinfo_to_string): Define.
+
 2015-07-30  Jason Merrill  <jason@redhat.com>
 
 	* c-pretty-print.c (unary_expression) [INDIRECT_REF]: Don't print
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index f0640c7..ff74e53 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1431,12 +1431,5 @@ extern bool contains_cilk_spawn_stmt (tree);
 extern tree cilk_for_number_of_iterations (tree);
 extern bool check_no_cilk (tree, const char *, const char *,
 		           location_t loc = UNKNOWN_LOCATION);
-/* In c-indentation.c.  */
-extern void
-warn_for_misleading_indentation (location_t guard_loc,
-				 location_t body_loc,
-				 location_t next_stmt_loc,
-				 enum cpp_ttype next_tok_type,
-				 const char *guard_kind);
 
 #endif /* ! GCC_C_COMMON_H */
diff --git a/gcc/c-family/c-indentation.c b/gcc/c-family/c-indentation.c
index 252467e..544b0d4 100644
--- a/gcc/c-family/c-indentation.c
+++ b/gcc/c-family/c-indentation.c
@@ -26,6 +26,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "stringpool.h"
 #include "stor-layout.h"
 #include "c-common.h"
+#include "c-indentation.h"
 
 extern cpp_options *cpp_opts;
 
@@ -184,11 +185,16 @@ detect_preprocessor_logic (expanded_location body_exploc,
    description of that function below.  */
 
 static bool
-should_warn_for_misleading_indentation (location_t guard_loc,
-					location_t body_loc,
-					location_t next_stmt_loc,
-					enum cpp_ttype next_tok_type)
+should_warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
+					const token_indent_info &body_tinfo,
+					const token_indent_info &next_tinfo)
 {
+  location_t guard_loc = guard_tinfo.location;
+  location_t body_loc = body_tinfo.location;
+  location_t next_stmt_loc = next_tinfo.location;
+
+  enum cpp_ttype next_tok_type = next_tinfo.type;
+
   /* Don't attempt to compare the indentation of BODY_LOC and NEXT_STMT_LOC
      if either are within macros.  */
   if (linemap_location_from_macro_expansion_p (line_table, body_loc)
@@ -214,7 +220,22 @@ should_warn_for_misleading_indentation (location_t guard_loc,
   if (line_table->seen_line_directive)
     return false;
 
-  if (next_tok_type == CPP_CLOSE_BRACE)
+  /* If the token following the body is a close brace or an "else"
+     then while indentation may be sloppy, there is not much ambiguity
+     about control flow, e.g.
+
+     if (foo)       <- GUARD
+       bar ();      <- BODY
+       else baz (); <- NEXT
+
+     {
+     while (foo)  <- GUARD
+     bar ();      <- BODY
+     }            <- NEXT
+     baz ();
+  */
+  if (next_tok_type == CPP_CLOSE_BRACE
+      || next_tinfo.keyword == RID_ELSE)
     return false;
 
   /* Don't warn here about spurious semicolons.  */
@@ -341,6 +362,28 @@ should_warn_for_misleading_indentation (location_t guard_loc,
   return false;
 }
 
+/* Return the string identifier corresponding to the given guard token.  */
+
+static const char *
+guard_tinfo_to_string (const token_indent_info &guard_tinfo)
+{
+  switch (guard_tinfo.keyword)
+    {
+    case RID_FOR:
+      return "for";
+    case RID_ELSE:
+      return "else";
+    case RID_IF:
+      return "if";
+    case RID_WHILE:
+      return "while";
+    case RID_DO:
+      return "do";
+    default:
+      gcc_unreachable ();
+    }
+}
+
 /* Called by the C/C++ frontends when we have a guarding statement at
    GUARD_LOC containing a statement at BODY_LOC, where the block wasn't
    written using braces, like this:
@@ -368,11 +411,9 @@ should_warn_for_misleading_indentation (location_t guard_loc,
    GUARD_KIND identifies the kind of clause e.g. "if", "else" etc.  */
 
 void
-warn_for_misleading_indentation (location_t guard_loc,
-				 location_t body_loc,
-				 location_t next_stmt_loc,
-				 enum cpp_ttype next_tok_type,
-				 const char *guard_kind)
+warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
+				 const token_indent_info &body_tinfo,
+				 const token_indent_info &next_tinfo)
 {
   /* Early reject for the case where -Wmisleading-indentation is disabled,
      to avoid doing work only to have the warning suppressed inside the
@@ -380,12 +421,14 @@ warn_for_misleading_indentation (location_t guard_loc,
   if (!warn_misleading_indentation)
     return;
 
-  if (should_warn_for_misleading_indentation (guard_loc,
-					      body_loc,
-					      next_stmt_loc,
-					      next_tok_type))
-    if (warning_at (next_stmt_loc, OPT_Wmisleading_indentation,
-		    "statement is indented as if it were guarded by..."))
-      inform (guard_loc,
-	      "...this %qs clause, but it is not", guard_kind);
+  if (should_warn_for_misleading_indentation (guard_tinfo,
+					      body_tinfo,
+					      next_tinfo))
+    {
+      if (warning_at (next_tinfo.location, OPT_Wmisleading_indentation,
+		      "statement is indented as if it were guarded by..."))
+        inform (guard_tinfo.location,
+		"...this %qs clause, but it is not",
+		guard_tinfo_to_string (guard_tinfo));
+    }
 }
diff --git a/gcc/c-family/c-indentation.h b/gcc/c-family/c-indentation.h
new file mode 100644
index 0000000..7fb6bb4
--- /dev/null
+++ b/gcc/c-family/c-indentation.h
@@ -0,0 +1,52 @@
+/* Definitions for c-indentation.c.
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_C_INDENTATION_H
+#define GCC_C_INDENTATION_H
+
+/* Token information used by the -Wmisleading-indentation implementation.  */
+
+struct token_indent_info
+{
+  location_t location;
+  ENUM_BITFIELD (cpp_ttype) type : 8;
+  ENUM_BITFIELD (rid) keyword : 8;
+};
+
+/* Extract token information from TOKEN, which ought to either be a
+   cp_token * or a c_token *.  */
+
+template <typename T>
+inline token_indent_info
+get_token_indent_info (const T *token)
+{
+  token_indent_info info;
+  info.location = token->location;
+  info.type = token->type;
+  info.keyword = token->keyword;
+
+  return info;
+}
+
+extern void
+warn_for_misleading_indentation (const token_indent_info &guard_tinfo,
+				 const token_indent_info &body_tinfo,
+				 const token_indent_info &next_tinfo);
+
+#endif  /* ! GCC_C_INDENTATION_H  */