Hi,
thus I have this simple patch which at least catches pure
self-delegation (no cycles). Better than nothing, I would say, given its
simplicity ;)
At first I thought I would put the check in expand_default_init but then
I noticed that in case of, eg, virtual bases, the simple pattern
matching (which looks inside CALL_EXPRs) would miss some cases, like
when the self-delegation is only in the derived type, not in the base.
Tested x86_64-linux.
Thanks!
Paolo.
/////////////////////////////
/cp
2013-08-29 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/51424
* cp-tree.h (LOOKUP_DELEGATING_CONS): Add.
* init.c (perform_target_ctor): Use it.
* call.c (build_special_member_call): Diagnose self-delegating
constructors.
/testsuite
2013-08-29 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/51424
* g++.dg/cpp0x/dc8.C: New.
* g++.dg/template/meminit1.C: Adjust.
Index: cp/call.c
===================================================================
--- cp/call.c (revision 202071)
+++ cp/call.c (working copy)
@@ -7442,6 +7442,14 @@ build_special_member_call (tree instance, tree nam
if (allocated != NULL)
release_tree_vector (allocated);
+ if ((complain & tf_error)
+ && (flags & LOOKUP_DELEGATING_CONS)
+ && name == complete_ctor_identifier
+ && TREE_CODE (ret) == CALL_EXPR
+ && (DECL_ABSTRACT_ORIGIN (TREE_OPERAND (CALL_EXPR_FN (ret), 0))
+ == current_function_decl))
+ error ("constructor delegates to itself");
+
return ret;
}
Index: cp/cp-tree.h
===================================================================
--- cp/cp-tree.h (revision 202071)
+++ cp/cp-tree.h (working copy)
@@ -4509,6 +4509,8 @@ enum overload_flags { NO_SPECIAL = 0, DTOR_FLAG, T
#define LOOKUP_NO_RVAL_BIND (LOOKUP_EXPLICIT_TMPL_ARGS << 1)
/* Used by case_conversion to disregard non-integral conversions. */
#define LOOKUP_NO_NON_INTEGRAL (LOOKUP_NO_RVAL_BIND << 1)
+/* Used for delegating constructors in order to diagnose self-delegation. */
+#define LOOKUP_DELEGATING_CONS (LOOKUP_NO_NON_INTEGRAL << 1)
#define LOOKUP_NAMESPACES_ONLY(F) \
(((F) & LOOKUP_PREFER_NAMESPACES) && !((F) & LOOKUP_PREFER_TYPES))
Index: cp/init.c
===================================================================
--- cp/init.c (revision 202071)
+++ cp/init.c (working copy)
@@ -500,8 +500,9 @@ perform_target_ctor (tree init)
tree decl = current_class_ref;
tree type = current_class_type;
- finish_expr_stmt (build_aggr_init (decl, init, LOOKUP_NORMAL,
- tf_warning_or_error));
+ finish_expr_stmt (build_aggr_init (decl, init,
+ LOOKUP_NORMAL|LOOKUP_DELEGATING_CONS,
+ tf_warning_or_error));
if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
{
tree expr = build_delete (type, decl, sfk_complete_destructor,
Index: testsuite/g++.dg/cpp0x/dc8.C
===================================================================
--- testsuite/g++.dg/cpp0x/dc8.C (revision 0)
+++ testsuite/g++.dg/cpp0x/dc8.C (working copy)
@@ -0,0 +1,66 @@
+// PR c++/51424
+// { dg-do compile { target c++11 } }
+
+template <class T >
+struct S
+{
+ S() : S() {} // { dg-error "delegates to itself" }
+ S(int x) : S(x) {} // { dg-error "delegates to itself" }
+};
+
+struct B1
+{
+ B1() : B1() {} // { dg-error "delegates to itself" }
+ B1(int y) : B1(y) {} // { dg-error "delegates to itself" }
+};
+
+struct V1 : virtual B1
+{
+ V1() : B1() {}
+ V1(int x) : B1(x) {}
+};
+
+struct B2
+{
+ B2() : B2() {} // { dg-error "delegates to itself" }
+ B2(int y) : B2(y) {} // { dg-error "delegates to itself" }
+};
+
+struct V2 : virtual B2
+{
+ V2() : V2() {} // { dg-error "delegates to itself" }
+ V2(int x) : V2(x) {} // { dg-error "delegates to itself" }
+};
+
+struct B3
+{
+ B3() {}
+ B3(int y) {}
+};
+
+struct V3 : virtual B3
+{
+ V3() : V3() {} // { dg-error "delegates to itself" }
+ V3(int x) : V3(x) {} // { dg-error "delegates to itself" }
+};
+
+struct CE1
+{
+ constexpr CE1() : CE1() {} // { dg-error "delegates to itself" }
+ constexpr CE1(int x) : CE1(x) {} // { dg-error "delegates to itself" }
+};
+
+struct CEB2
+{
+ constexpr CEB2() : CEB2() {} // { dg-error "delegates to itself" }
+ constexpr CEB2(int x) : CEB2(x) {} // { dg-error "delegates to itself" }
+};
+
+struct CE2 : CEB2
+{
+ constexpr CE2() : CEB2() {}
+ constexpr CE2(int x) : CEB2(x) {}
+};
+
+S<int> s1;
+S<int> s2(1);
Index: testsuite/g++.dg/template/meminit1.C
===================================================================
--- testsuite/g++.dg/template/meminit1.C (revision 202068)
+++ testsuite/g++.dg/template/meminit1.C (working copy)
@@ -3,6 +3,6 @@ template <class T >
struct S
{
S() : S() {} // { dg-message "delegating constructors" }
-};
+}; // { dg-error "delegates to itself" "" { target *-*-* } 5 }
S<int> s;
