+2009-06-06 Ian Lance Taylor <iant@google.com>
+
+ * doc/extend.texi (Attribute Syntax): Document that C++ labels on
+ empty statements can now have attributes.
+
2009-06-05 Shujing Zhao <pearly.zhao@oracle.com>
* config/mips/mips.c: Use REG_P and CONST_INT_P where applicable.
+2009-06-06 Ian Lance Taylor <iant@google.com>
+
+ * parser.c (cp_parser_label_for_labeled_statement): Support
+ attribute on labels if immediately followed by semicolon.
+ * semantics.c (finish_label_stmt): Return new label.
+ * pt.c (tsubst_expr): Handle attributes for LABEL_EXPR.
+
2009-06-03 Ian Lance Taylor <iant@google.com>
* Make-lang.in (cc1plus-checksum.o): Depend upon $(CONFIG_H) and
cp_parser_label_for_labeled_statement (cp_parser* parser)
{
cp_token *token;
+ tree label = NULL_TREE;
/* The next token should be an identifier. */
token = cp_lexer_peek_token (parser->lexer);
default:
/* Anything else must be an ordinary label. */
- finish_label_stmt (cp_parser_identifier (parser));
+ label = finish_label_stmt (cp_parser_identifier (parser));
break;
}
/* Require the `:' token. */
cp_parser_require (parser, CPP_COLON, "%<:%>");
+
+ /* An ordinary label may optionally be followed by attributes.
+ However, this is only permitted if the attributes are then
+ followed by a semicolon. This is because, for backward
+ compatibility, when parsing
+ lab: __attribute__ ((unused)) int i;
+ we want the attribute to attach to "i", not "lab". */
+ if (label != NULL_TREE
+ && cp_lexer_next_token_is_keyword (parser->lexer, RID_ATTRIBUTE))
+ {
+ tree attrs;
+
+ cp_parser_parse_tentatively (parser);
+ attrs = cp_parser_attributes_opt (parser);
+ if (attrs == NULL_TREE
+ || cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
+ cp_parser_abort_tentative_parse (parser);
+ else if (!cp_parser_parse_definitely (parser))
+ ;
+ else
+ cplus_decl_attributes (&label, attrs, 0);
+ }
}
/* Parse an expression-statement.
break;
case LABEL_EXPR:
- finish_label_stmt (DECL_NAME (LABEL_EXPR_LABEL (t)));
+ {
+ tree decl = LABEL_EXPR_LABEL (t);
+ tree label;
+
+ label = finish_label_stmt (DECL_NAME (decl));
+ if (DECL_ATTRIBUTES (decl) != NULL_TREE)
+ cplus_decl_attributes (&label, DECL_ATTRIBUTES (decl), 0);
+ }
break;
case GOTO_EXPR:
return add_stmt (r);
}
-/* Finish a label with the indicated NAME. */
+/* Finish a label with the indicated NAME. Returns the new label. */
tree
finish_label_stmt (tree name)
{
tree decl = define_label (input_location, name);
- if (decl == error_mark_node)
+ if (decl == error_mark_node)
return error_mark_node;
- return add_stmt (build_stmt (LABEL_EXPR, decl));
+ add_stmt (build_stmt (LABEL_EXPR, decl));
+
+ return decl;
}
/* Finish a series of declarations for local labels. G++ allows users
that may be unused but which is compiled with @option{-Wall}. It would
not normally be appropriate to use in it human-written code, though it
could be useful in cases where the code that jumps to the label is
-contained within an @code{#ifdef} conditional. GNU C++ does not permit
-such placement of attribute lists, as it is permissible for a
-declaration, which could begin with an attribute list, to be labelled in
-C++. Declarations cannot be labelled in C90 or C99, so the ambiguity
-does not arise there.
+contained within an @code{#ifdef} conditional. GNU C++ only permits
+attributes on labels if the attribute specifier is immediately
+followed by a semicolon (i.e., the label applies to an empty
+statement). If the semicolon is missing, C++ label attributes are
+ambiguous, as it is permissible for a declaration, which could begin
+with an attribute list, to be labelled in C++. Declarations cannot be
+labelled in C90 or C99, so the ambiguity does not arise there.
An attribute specifier list may appear as part of a @code{struct},
@code{union} or @code{enum} specifier. It may go either immediately
+2009-06-06 Ian Lance Taylor <iant@google.com>
+
+ * gcc.dg/Wunused-label-1.c: New test case.
+ * g++.dg/warn/Wunused-label-1.C: New test case.
+ * g++.dg/warn/Wunused-label-2.C: New test case.
+ * g++.dg/warn/Wunused-label-3.C: New test case.
+
2009-06-06 Daniel Franke <franke.daniel@gmail.com>
PR fortran/37203
--- /dev/null
+// { dg-do compile }
+// { dg-options "-Wunused-label" }
+
+extern void f9();
+
+void
+f1()
+{
+ l1: f9(); // { dg-warning "not used" }
+ l3: ; f9(); // { dg-warning "not used" }
+ l4: __attribute__ ((unused)) ; f9();
+}
+
+void
+f2()
+{
+ label: __attribute ((unused)) ;
+}
+
+void
+f3()
+{
+ // The next line would be OK in C but is a syntax error in C++.
+ l2: __attribute__ ((unused)) f9(); // { dg-error "expected" }
+ // We still get an unused label warning--this is
+ // optional and can be removed if it ever changes.
+ // { dg-warning "not used" "expected" { target *-*-* } 24 }
+}
--- /dev/null
+// { dg-do compile }
+// { dg-options "-Wunused" }
+
+// If __attribute__ ((unused)) follows a label and precedes a
+// declaration, we should get a warning for the label, not the
+// declaration.
+
+void
+f1()
+{
+ int i1; // { dg-warning "unused variable" }
+ l1: __attribute__ ((unused)) int i2; // { dg-warning "label \[^\n\]* not used" }
+}
--- /dev/null
+// { dg-do compile }
+// { dg-options "-Wunused-label" }
+
+extern void f9();
+
+template<int i>
+void
+f1()
+{
+ if (i)
+ return;
+
+ l1: f9(); // { dg-warning "not used" }
+ l3: ; f9(); // { dg-warning "not used" }
+ l4: __attribute__ ((unused)) ; f9();
+}
+
+template
+void f1<0>();
+
+template<int i>
+void
+f2()
+{
+ if (i)
+ return;
+
+ l1: f9(); // { dg-warning "not used" }
+ l3: ; f9(); // { dg-warning "not used" }
+ l4: __attribute__ ((unused)) ; f9();
+}
+
+template
+void f2<1>();
+
+template<int i>
+void
+f3()
+{
+ void* lab;
+ l1: f9();
+ l2: __attribute__ ((unused)) ; f9();
+ lab = i ? &&l1 : &&l2;
+ goto *lab;
+}
+
+template
+void f3<0>();
+
+template
+void f3<1>();
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-Wunused-label" } */
+
+extern void f2 ();
+
+void
+f1 ()
+{
+ l1: f2 (); /* { dg-warning "not used" } */
+ l2: __attribute__ ((unused)) f2 ();
+ l3: ; f2 (); /* { dg-warning "not used" } */
+ l4: __attribute__ ((unused)) ; f2 ();
+}
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