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[C++ PATCH] Don't treat enumeration vals as lvalues (PR c++/41131)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Jason Merrill <jason at redhat dot com>, Mark Mitchell <mark at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 20 Aug 2009 23:44:04 +0200
- Subject: [C++ PATCH] Don't treat enumeration vals as lvalues (PR c++/41131)
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
When Obj-C++ support was added, CONST_DECL handling has been added to
lvalue_p_1. As CONST_DECL are used in C++ land just for enumeration values,
I assume it could be only because of objc_build_string_object which creates
a CONST_DECL and creates ADDR_EXPR from it.
The following patch stops treating enumeration values as lvalues again,
just handles the special ObjC CONST_DECL.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.4?
2009-08-20 Jakub Jelinek <jakub@redhat.com>
PR c++/41131
* tree.c (lvalue_p_1) <case CONST_DECL>: Return clk_none if
not TREE_STATIC.
* g++.dg/expr/unary3.C: New test.
--- gcc/cp/tree.c.jj 2009-08-19 17:46:00.000000000 +0200
+++ gcc/cp/tree.c 2009-08-20 21:16:00.000000000 +0200
@@ -132,6 +132,12 @@ lvalue_p_1 (const_tree ref)
return clk_ordinary;
case CONST_DECL:
+ /* CONST_DECL without TREE_STATIC are enumeration values and
+ thus not lvalues. With TREE_STATIC they are used by ObjC++
+ in objc_build_string_object and need to be considered as
+ lvalues. */
+ if (! TREE_STATIC (ref))
+ return clk_none;
case VAR_DECL:
if (TREE_READONLY (ref) && ! TREE_STATIC (ref)
&& DECL_LANG_SPECIFIC (ref)
--- gcc/testsuite/g++.dg/expr/unary3.C.jj 2009-08-20 21:21:18.000000000 +0200
+++ gcc/testsuite/g++.dg/expr/unary3.C 2009-08-20 21:19:32.000000000 +0200
@@ -0,0 +1,11 @@
+// PR c++/41131
+// { dg-do compile }
+
+struct X { enum E { a = 100 }; };
+
+int
+main ()
+{
+ X x;
+ (void) &x.a; // { dg-error "lvalue required" }
+}
Jakub