invoke.texi (Warning Options): Document that -Wempty-body also checks for and while...

	* doc/invoke.texi (Warning Options): Document that -Wempty-body
	also checks for and while statements in C++.

cp:
	* parser.c (check_empty_body): Add.
	(cp_parser_iteration_statement): Add call to check_empty_body.

testsuite:
	* g++.old-deja/g++.mike/empty.C: Add.

From-SVN: r124534

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c57813d40314ab7f621c05c8b2407845585a326a..22b09d4fc5fe517805ec9d2fed64b0e1d4d74e4c 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2007-05-07  Mike Stump  <mrs@apple.com>
+
+       * doc/invoke.texi (Warning Options): Document that -Wempty-body
+       also checks for and while statements in C++.
+
 2007-05-07  Nathan Froyd  <froydnj@codesourcery.com>
 
        * gcc.c (at_file_supplied): New variable.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b4a1c9a1b0a3eb1fcb14e8f89106462499b9f9d0..e0286ff6505f3ad042beb5721656ebd76e71ef3a 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2007-05-07  Mike Stump  <mrs@apple.com>
+
+       * parser.c (check_empty_body): Add.
+       (cp_parser_iteration_statement): Add call to check_empty_body.
+
 2007-05-05  Geoffrey Keating  <geoffk@apple.com>
 
        PR 31775

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 63f7fec0169b63540fac06732a895c61f55feb80..4599aca0166aa91acee1e6a47b41ab971c16838f 100644 (file)
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -7065,6 +7065,51 @@ cp_parser_condition (cp_parser* parser)
   return cp_parser_expression (parser, /*cast_p=*/false);
 }
 
+/* We check for a ) immediately followed by ; with no whitespacing
+   between.  This is used to issue a warning for:
+
+     while (...);
+
+   and:
+
+     for (...);
+
+   as the semicolon is probably extraneous.
+
+   On parse errors, the next token might not be a ), so do nothing in
+   that case. */
+
+static void
+check_empty_body (cp_parser* parser, const char* type)
+{
+  cp_token *token;
+  cp_token *close_paren;
+  expanded_location close_loc;
+  expanded_location semi_loc;
+  
+  close_paren = cp_lexer_peek_token (parser->lexer);
+  if (close_paren->type != CPP_CLOSE_PAREN)
+    return;
+
+  close_loc = expand_location (close_paren->location);
+  token = cp_lexer_peek_nth_token (parser->lexer, 2);
+
+  if (token->type != CPP_SEMICOLON
+      || (token->flags & PREV_WHITE))
+    return;
+
+  semi_loc =  expand_location (token->location);
+  if (close_loc.line == semi_loc.line
+#ifdef USE_MAPPED_LOCATION
+      && close_loc.column+1 == semi_loc.column
+#endif
+      )
+    warning (OPT_Wempty_body,
+            "suggest a space before %<;%> or explicit braces around empty "
+            "body in %<%s%> statement",
+            type);
+}
+
 /* Parse an iteration-statement.
 
    iteration-statement:
@@ -7107,6 +7152,7 @@ cp_parser_iteration_statement (cp_parser* parser)
        /* Parse the condition.  */
        condition = cp_parser_condition (parser);
        finish_while_stmt_cond (condition, statement);
+       check_empty_body (parser, "while");
        /* Look for the `)'.  */
        cp_parser_require (parser, CPP_CLOSE_PAREN, "`)'");
        /* Parse the dependent statement.  */
@@ -7168,6 +7214,7 @@ cp_parser_iteration_statement (cp_parser* parser)
        if (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_PAREN))
          expression = cp_parser_expression (parser, /*cast_p=*/false);
        finish_for_expr (expression, statement);
+       check_empty_body (parser, "for");
        /* Look for the `)'.  */
        cp_parser_require (parser, CPP_CLOSE_PAREN, "`)'");
 

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index e608dbc017e9e46d4b13ca020c268f73647e7c84..552e3b731b03a5dc6e86ef7c52734c6f4674c50e 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -3157,6 +3157,11 @@ An empty body occurs in an @samp{if}, @samp{else} or
 @samp{do while} statement. This warning can be independently
 controlled by @option{-Wempty-body}.
 
+@item @r{(C++ only)}
+An empty body occurs in a @samp{while} or @samp{for} statement with no
+whitespacing before the semicolon. This warning can be independently
+controlled by @option{-Wempty-body}.
+
 @item
 A pointer is compared against integer zero with @samp{<}, @samp{<=},
 @samp{>}, or @samp{>=}.
@@ -3421,8 +3426,10 @@ to them.
 
 @item -Wempty-body
 @opindex Wempty-body
-An empty body occurs in an @samp{if}, @samp{else} or @samp{do while}
-statement.  This warning is also enabled by @option{-Wextra}.
+Warn if an empty body occurs in an @samp{if}, @samp{else} or @samp{do
+while} statement.  Additionally, in C++, warn when an empty body occurs
+in a @samp{while} or @samp{for} statement with no whitespacing before
+the semicolon.  This warning is also enabled by @option{-Wextra}.
 
 @item -Wsign-compare
 @opindex Wsign-compare

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8c0103f28d919fc8d58a3b013e813f9215680256..6b6f3953b34849538eb96fd745c373e17b0e61a6 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2007-05-07  Mike Stump  <mrs@apple.com>
+
+       * g++.old-deja/g++.mike/empty.C: Add.
+
 2007-05-07  Eric Christopher  <echristo@apple.com>
 
        * gcc.dg/invalid-call-1.c: Fix options for 32-bit x86.

diff --git a/gcc/testsuite/g++.old-deja/g++.mike/empty.C b/gcc/testsuite/g++.old-deja/g++.mike/empty.C
new file mode 100644 (file)
index 0000000..d69f3ad
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.mike/empty.C
@@ -0,0 +1,25 @@
+// { dg-options "-W" }
+
+#define NOPE
+
+void foo() {
+  while (1); /* { dg-error "suggest a space before " } */
+    {
+    }
+  for (;;); /* { dg-error "suggest a space before " } */
+    {
+    }
+  while (1)
+    ;
+  for (;;)
+    ;
+  while (1) ;
+  for (;;) ;
+  /* These two work when using mapped locations */
+  while (1) NOPE; /* { dg-bogus "suggest a space before " "suggest" { xfail *-*-* } } */
+  for (;;) NOPE; /* { dg-bogus "suggest a space before " "suggest" { xfail *-*-* } } */
+  while (1)
+    NOPE;
+  for (;;)
+    NOPE;
+}