This routine patch fixes PR objc/48187. The problem is that the following code
@interface A
{
]
}
@end
would cause the ObjC parser to enter into an infinite loop. The parser
fails to parse ] as an instance variable, but then when it tries to skip
to the next semicolon to resume parsing from the next instance variable,
the standard c_parser_skip_until_found() doesn't skip the ] because it's
a special token that reduces the nesting level. So, the parser tries to
parse ] again as an instance variable, and then again and again, failing
to ever make any progress ;-)
The fix adds an explicit branch to deal with the parsing failure, and carefully
skips to the next semicolon (or '}) even in the case of ']' or ')'.
--
As I was looking at that chunk of code, I also noticed the error message saying
"extra semicolon in struct or union specified" for an extra semicolon found in a
list of ObjC instance variables. I think it's incorrect or at least confusing
as a list of ObjC instance variables isn't a "struct or union". ;-)
I changed it to simply say "extra semicolon" as I like short and clear error
messages.
But I'm happy to change it to something else (eg, "extra semicolon specified in
list
of Objective-C instance variables") if other people disagree.
--
I added testcases.
--
Finally, I also updated the ObjC++ parser so that it would survive the same
testcases
(previously they would crash the compiler).
Ok to commit ?
Thanks
Index: ChangeLog
===================================================================
--- ChangeLog (revision 174112)
+++ ChangeLog (working copy)
@@ -1,3 +1,11 @@
+2011-05-24 Nicola Pero <[email protected]>
+
+ PR objc/48187
+ * c-parser.c (c_parser_objc_class_instance_variables): More robust
+ parsing of syntax error in ObjC instance variable lists. In
+ particular, avoid an infinite loop if there is a stray ']'.
+ Updated error message.
+
2011-05-24 Joseph Myers <[email protected]>
* Makefile.in (GCC_OBJS): Remove opts-common.o and options.o.
Index: testsuite/ChangeLog
===================================================================
--- testsuite/ChangeLog (revision 174112)
+++ testsuite/ChangeLog (working copy)
@@ -1,3 +1,10 @@
+2011-05-24 Nicola Pero <[email protected]>
+
+ PR objc/48187
+ * objc.dg/pr48187.m: New testcase.
+ * obj-c++.dg/pr48187.mm: New testcase.
+ * objc.dg/ivar-extra-semicolon.m: New testcase.
+
2011-05-24 Tom de Vries <[email protected]>
PR tree-optimization/49121
Index: testsuite/objc.dg/ivar-extra-semicolon.m
===================================================================
--- testsuite/objc.dg/ivar-extra-semicolon.m (revision 0)
+++ testsuite/objc.dg/ivar-extra-semicolon.m (revision 0)
@@ -0,0 +1,15 @@
+/* Contributed by Nicola Pero <[email protected]>, May 2011. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+
+#include <objc/objc.h>
+
+@interface MyClass
+{
+ ; /* { dg-warning "extra semicolon" } */
+ int a;
+ ; /* { dg-warning "extra semicolon" } */
+ int b;
+ ; /* { dg-warning "extra semicolon" } */
+}
+@end
Index: testsuite/objc.dg/pr48187.m
===================================================================
--- testsuite/objc.dg/pr48187.m (revision 0)
+++ testsuite/objc.dg/pr48187.m (revision 0)
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+
+@interface A
+{
+ ] /* { dg-error "xpected" } */
+}
+@end
+
+@interface B
+{
+ ]; /* { dg-error "xpected" } */
+}
+@end
+
+@interface C
+{
+ ]; /* { dg-error "xpected" } */
+ int x;
+}
+@end
+
+@interface D
+{
+ ) /* { dg-error "xpected" } */
+}
+@end
+
+@interface E
+{
+ ); /* { dg-error "xpected" } */
+}
+@end
+
+@interface F
+{
+ ); /* { dg-error "xpected" } */
+ int x;
+}
+@end
Index: testsuite/obj-c++.dg/pr48187.mm
===================================================================
--- testsuite/obj-c++.dg/pr48187.mm (revision 0)
+++ testsuite/obj-c++.dg/pr48187.mm (revision 0)
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+
+@interface A
+{
+ ] /* { dg-error "xpected" } */
+}
+@end
+
+@interface B
+{
+ ]; /* { dg-error "xpected" } */
+}
+@end
+
+@interface C
+{
+ ]; /* { dg-error "xpected" } */
+ int x;
+}
+@end
+
+@interface D
+{
+ (
+} /* { dg-error "xpected" } */
+@end
+
+@interface E
+{
+ (; /* { dg-error "xpected" } */
+}
+@end
+
+@interface F
+{
+ (; /* { dg-error "xpected" } */
+ int x;
+}
+@end
Index: cp/ChangeLog
===================================================================
--- cp/ChangeLog (revision 174112)
+++ cp/ChangeLog (working copy)
@@ -1,3 +1,8 @@
+2011-05-24 Nicola Pero <[email protected]>,
+
+ * parser.c (cp_parser_objc_class_ivars): Deal gracefully with a
+ syntax error in declaring an ObjC instance variable.
+
2011-05-24 Joseph Myers <[email protected]>
* Make-lang.in (GXX_OBJS): Remove prefix.o.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 174112)
+++ cp/parser.c (working copy)
@@ -22494,7 +22494,8 @@ cp_parser_objc_class_ivars (cp_parser* parser)
NULL_TREE, attributes);
/* Add the instance variable. */
- objc_add_instance_variable (decl);
+ if (decl != error_mark_node && decl != NULL_TREE)
+ objc_add_instance_variable (decl);
/* Reset PREFIX_ATTRIBUTES. */
while (attributes && TREE_CHAIN (attributes) != first_attribute)
Index: c-parser.c
===================================================================
--- c-parser.c (revision 174112)
+++ c-parser.c (working copy)
@@ -6945,7 +6945,7 @@ c_parser_objc_class_instance_variables (c_parser *
if (c_parser_next_token_is (parser, CPP_SEMICOLON))
{
pedwarn (c_parser_peek_token (parser)->location, OPT_pedantic,
- "extra semicolon in struct or union specified");
+ "extra semicolon");
c_parser_consume_token (parser);
continue;
}
@@ -6988,13 +6988,34 @@ c_parser_objc_class_instance_variables (c_parser *
/* Parse some comma-separated declarations. */
decls = c_parser_struct_declaration (parser);
- {
- /* Comma-separated instance variables are chained together in
- reverse order; add them one by one. */
- tree ivar = nreverse (decls);
- for (; ivar; ivar = DECL_CHAIN (ivar))
- objc_add_instance_variable (copy_node (ivar));
- }
+ if (decls == NULL)
+ {
+ /* There is a syntax error. We want to skip the offending
+ tokens up to the next ';' (included) or '}'
+ (excluded). */
+
+ /* First, skip manually a ')' or ']'. This is because they
+ reduce the nesting level, so c_parser_skip_until_found()
+ wouldn't be able to skip past them. */
+ c_token *token = c_parser_peek_token (parser);
+ if (token->type == CPP_CLOSE_PAREN || token->type == CPP_CLOSE_SQUARE)
+ c_parser_consume_token (parser);
+
+ /* Then, do the standard skipping. */
+ c_parser_skip_until_found (parser, CPP_SEMICOLON, NULL);
+
+ /* We hopefully recovered. Start normal parsing again. */
+ parser->error = false;
+ continue;
+ }
+ else
+ {
+ /* Comma-separated instance variables are chained together
+ in reverse order; add them one by one. */
+ tree ivar = nreverse (decls);
+ for (; ivar; ivar = DECL_CHAIN (ivar))
+ objc_add_instance_variable (copy_node (ivar));
+ }
c_parser_skip_until_found (parser, CPP_SEMICOLON, "expected %<;%>");
}
}
