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C++ PATCH for c++/53733 (DR 1402, deleting move ctor)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Cc: Paolo Carlini <paolo dot carlini at oracle dot com>
- Date: Tue, 10 Jul 2012 02:04:53 +0200
- Subject: C++ PATCH for c++/53733 (DR 1402, deleting move ctor)
Apparently we need to implement DR 1402 in 4.7 in order to fix the
std::pair ABI breakage properly. So here it is: if overload resolution
chooses a non-trivial copy constructor, instead of causing the move
constructor to be deleted, we just don't implicitly declare it.
Tested x86_64-pc-linux-gnu, applying to trunk and 4.7.
While I was looking at this, I noticed that my earlier fix to handling
of cleanups vs. ctor exception specifications was incomplete, so I've
fixed that too.
commit e962a2624b47d4a46786ba0ba4d499928323f30c
Author: Jason Merrill <jason@redhat.com>
Date: Tue Jul 10 01:59:11 2012 +0200
DR 1402
PR c++/53733
* cp-tree.h (FNDECL_SUPPRESS_IMPLICIT_DECL): New.
(struct lang_decl_fn): Add suppress_implicit_decl field.
* method.c (implicitly_declare_fn): Check it.
(process_subob_fn): Add no_implicit_p parm.
(walk_field_subobs, synthesized_method_walk): Likewise.
(maybe_explain_implicit_delete): Adjust.
(explain_implicit_non_constexpr): Adjust.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 713001e..10efa2a 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1940,7 +1940,7 @@ struct GTY(()) lang_decl_fn {
unsigned thunk_p : 1;
unsigned this_thunk_p : 1;
unsigned hidden_friend_p : 1;
- /* 1 spare bit. */
+ unsigned suppress_implicit_decl : 1;
/* For a non-thunk function decl, this is a tree list of
friendly classes. For a thunk function decl, it is the
@@ -3107,6 +3107,12 @@ more_aggr_init_expr_args_p (const aggr_init_expr_arg_iterator *iter)
#define DECL_HIDDEN_FRIEND_P(NODE) \
(LANG_DECL_FN_CHECK (DECL_COMMON_CHECK (NODE))->hidden_friend_p)
+/* Nonzero if NODE is a FUNCTION_DECL generated by implicitly_declare_fn
+ that we shouldn't actually declare implicitly; it is only used for
+ comparing to an =default declaration. */
+#define FNDECL_SUPPRESS_IMPLICIT_DECL(NODE) \
+ (LANG_DECL_FN_CHECK (DECL_COMMON_CHECK (NODE))->suppress_implicit_decl)
+
/* Nonzero if DECL has been declared threadprivate by
#pragma omp threadprivate. */
#define CP_DECL_THREADPRIVATE_P(DECL) \
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 7ea2de9..79edf81 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -922,7 +922,7 @@ get_copy_assign (tree type)
static void
process_subob_fn (tree fn, bool move_p, tree *spec_p, bool *trivial_p,
- bool *deleted_p, bool *constexpr_p,
+ bool *deleted_p, bool *constexpr_p, bool *no_implicit_p,
const char *msg, tree arg)
{
if (!fn || fn == error_mark_node)
@@ -948,12 +948,10 @@ process_subob_fn (tree fn, bool move_p, tree *spec_p, bool *trivial_p,
}
}
+ /* Core 1402: A non-trivial copy op suppresses the implicit
+ declaration of the move ctor/op=. */
if (move_p && !move_fn_p (fn) && !trivial_fn_p (fn))
- {
- if (msg)
- error (msg, arg);
- goto bad;
- }
+ *no_implicit_p = true;
if (constexpr_p && !DECL_DECLARED_CONSTEXPR_P (fn))
{
@@ -980,8 +978,8 @@ static void
walk_field_subobs (tree fields, tree fnname, special_function_kind sfk,
int quals, bool copy_arg_p, bool move_p,
bool assign_p, tree *spec_p, bool *trivial_p,
- bool *deleted_p, bool *constexpr_p, const char *msg,
- int flags, tsubst_flags_t complain)
+ bool *deleted_p, bool *constexpr_p, bool *no_implicit_p,
+ const char *msg, int flags, tsubst_flags_t complain)
{
tree field;
for (field = fields; field; field = DECL_CHAIN (field))
@@ -1079,7 +1077,8 @@ walk_field_subobs (tree fields, tree fnname, special_function_kind sfk,
{
walk_field_subobs (TYPE_FIELDS (mem_type), fnname, sfk, quals,
copy_arg_p, move_p, assign_p, spec_p, trivial_p,
- deleted_p, constexpr_p, msg, flags, complain);
+ deleted_p, constexpr_p, no_implicit_p,
+ msg, flags, complain);
continue;
}
@@ -1096,7 +1095,7 @@ walk_field_subobs (tree fields, tree fnname, special_function_kind sfk,
rval = locate_fn_flags (mem_type, fnname, argtype, flags, complain);
process_subob_fn (rval, move_p, spec_p, trivial_p, deleted_p,
- constexpr_p, msg, field);
+ constexpr_p, no_implicit_p, msg, field);
}
}
@@ -1110,7 +1109,7 @@ walk_field_subobs (tree fields, tree fnname, special_function_kind sfk,
static void
synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
tree *spec_p, bool *trivial_p, bool *deleted_p,
- bool *constexpr_p, bool diag)
+ bool *constexpr_p, bool *no_implicit_p, bool diag)
{
tree binfo, base_binfo, scope, fnname, rval, argtype;
bool move_p, copy_arg_p, assign_p, expected_trivial, check_vdtor;
@@ -1198,6 +1197,9 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
if (trivial_p)
*trivial_p = expected_trivial;
+ if (no_implicit_p)
+ *no_implicit_p = false;
+
/* The TYPE_HAS_COMPLEX_* flags tell us about constraints from base
class versions and other properties of the type. But a subobject
class can be trivially copyable and yet have overload resolution
@@ -1256,7 +1258,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
rval = locate_fn_flags (base_binfo, fnname, argtype, flags, complain);
process_subob_fn (rval, move_p, spec_p, trivial_p, deleted_p,
- constexpr_p, msg, basetype);
+ constexpr_p, no_implicit_p, msg, basetype);
if (ctor_p && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (basetype))
{
/* In a constructor we also need to check the subobject
@@ -1269,7 +1271,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
throw) or exception-specification (a throw from one of the
dtors would be a double-fault). */
process_subob_fn (rval, false, NULL, NULL,
- deleted_p, NULL, NULL,
+ deleted_p, NULL, NULL, NULL,
basetype);
}
@@ -1310,13 +1312,13 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
rval = locate_fn_flags (base_binfo, fnname, argtype, flags, complain);
process_subob_fn (rval, move_p, spec_p, trivial_p, deleted_p,
- constexpr_p, msg, basetype);
+ constexpr_p, no_implicit_p, msg, basetype);
if (ctor_p && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (basetype))
{
rval = locate_fn_flags (base_binfo, complete_dtor_identifier,
NULL_TREE, flags, complain);
process_subob_fn (rval, false, NULL, NULL,
- deleted_p, NULL, NULL,
+ deleted_p, NULL, NULL, NULL,
basetype);
}
}
@@ -1331,13 +1333,14 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
"constructor or trivial copy constructor");
walk_field_subobs (TYPE_FIELDS (ctype), fnname, sfk, quals,
copy_arg_p, move_p, assign_p, spec_p, trivial_p,
- deleted_p, constexpr_p, msg, flags, complain);
+ deleted_p, constexpr_p, no_implicit_p,
+ msg, flags, complain);
if (ctor_p)
walk_field_subobs (TYPE_FIELDS (ctype), complete_dtor_identifier,
sfk_destructor, TYPE_UNQUALIFIED, false,
false, false, NULL, NULL,
deleted_p, NULL,
- NULL, flags, complain);
+ NULL, NULL, flags, complain);
pop_scope (scope);
@@ -1407,7 +1410,7 @@ maybe_explain_implicit_delete (tree decl)
"definition would be ill-formed:", decl);
pop_scope (scope);
synthesized_method_walk (ctype, sfk, const_p,
- NULL, NULL, NULL, NULL, true);
+ NULL, NULL, NULL, NULL, NULL, true);
}
input_location = loc;
@@ -1427,7 +1430,7 @@ explain_implicit_non_constexpr (tree decl)
bool dummy;
synthesized_method_walk (DECL_CLASS_CONTEXT (decl),
special_function_p (decl), const_p,
- NULL, NULL, NULL, &dummy, true);
+ NULL, NULL, NULL, &dummy, NULL, true);
}
/* Implicitly declare the special function indicated by KIND, as a
@@ -1451,6 +1454,7 @@ implicitly_declare_fn (special_function_kind kind, tree type, bool const_p)
bool deleted_p;
bool trivial_p;
bool constexpr_p;
+ bool no_implicit_p;
/* Because we create declarations for implicitly declared functions
lazily, we may be creating the declaration for a member of TYPE
@@ -1520,7 +1524,7 @@ implicitly_declare_fn (special_function_kind kind, tree type, bool const_p)
}
synthesized_method_walk (type, kind, const_p, &raises, &trivial_p,
- &deleted_p, &constexpr_p, false);
+ &deleted_p, &constexpr_p, &no_implicit_p, false);
/* Don't bother marking a deleted constructor as constexpr. */
if (deleted_p)
constexpr_p = false;
@@ -1585,6 +1589,7 @@ implicitly_declare_fn (special_function_kind kind, tree type, bool const_p)
DECL_DELETED_FN (fn) = deleted_p;
DECL_DECLARED_CONSTEXPR_P (fn) = constexpr_p;
}
+ FNDECL_SUPPRESS_IMPLICIT_DECL (fn) = no_implicit_p;
DECL_EXTERNAL (fn) = true;
DECL_NOT_REALLY_EXTERN (fn) = 1;
DECL_DECLARED_INLINE_P (fn) = 1;
@@ -1777,6 +1782,10 @@ lazily_declare_fn (special_function_kind sfk, tree type)
|| sfk == sfk_move_assignment))
return NULL_TREE;
+ /* We also suppress implicit move if it would call a non-trivial copy. */
+ if (FNDECL_SUPPRESS_IMPLICIT_DECL (fn))
+ return NULL_TREE;
+
/* A destructor may be virtual. */
if (sfk == sfk_destructor
|| sfk == sfk_move_assignment
diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted21.C b/gcc/testsuite/g++.dg/cpp0x/defaulted21.C
index 30a4a7c..51505dc 100644
--- a/gcc/testsuite/g++.dg/cpp0x/defaulted21.C
+++ b/gcc/testsuite/g++.dg/cpp0x/defaulted21.C
@@ -3,7 +3,8 @@
struct U {
U();
- U(U const&);
+private:
+ U(U const&); // { dg-error "private" }
};
struct X {
@@ -13,7 +14,7 @@ struct X {
};
X::X(X&&)=default; // { dg-message "implicitly deleted" }
-// { dg-error "does not have a move constructor" "" { target *-*-* } 15 }
+// { dg-prune-output "within this context" }
X f() {
return X();
diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted36.C b/gcc/testsuite/g++.dg/cpp0x/defaulted36.C
new file mode 100644
index 0000000..1360f60
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/defaulted36.C
@@ -0,0 +1,24 @@
+// PR c++/53733
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+struct wrap
+{
+ wrap() = default;
+ wrap(wrap&&) = default; // Line 5
+ wrap(const wrap&) = default;
+
+ T t;
+};
+
+struct S {
+ S() = default;
+ S(const S&){}
+ S(S&&) = default;
+};
+
+typedef wrap<const S> W;
+
+W get() { return W(); } // Line 19
+
+int main() {}
commit d0334cc0204e8bff2aada54b8f9c73fdc3ebcd50
Author: Jason Merrill <jason@redhat.com>
Date: Tue Jul 10 01:42:02 2012 +0200
* method.c (synthesized_method_walk): Avoid changing
EH spec based on cleanups in other places, too.
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 0237456..7ea2de9 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -1315,7 +1315,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
{
rval = locate_fn_flags (base_binfo, complete_dtor_identifier,
NULL_TREE, flags, complain);
- process_subob_fn (rval, false, spec_p, NULL,
+ process_subob_fn (rval, false, NULL, NULL,
deleted_p, NULL, NULL,
basetype);
}
@@ -1335,7 +1335,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
if (ctor_p)
walk_field_subobs (TYPE_FIELDS (ctype), complete_dtor_identifier,
sfk_destructor, TYPE_UNQUALIFIED, false,
- false, false, spec_p, NULL,
+ false, false, NULL, NULL,
deleted_p, NULL,
NULL, flags, complain);
diff --git a/gcc/testsuite/g++.dg/cpp0x/implicit13.C b/gcc/testsuite/g++.dg/cpp0x/implicit13.C
index 96bc770..3165863 100644
--- a/gcc/testsuite/g++.dg/cpp0x/implicit13.C
+++ b/gcc/testsuite/g++.dg/cpp0x/implicit13.C
@@ -14,7 +14,7 @@ struct B: A { };
// { dg-final { scan-assembler-not "_ZN1BC1Ev" } }
B b;
-struct C { C() noexcept; ~C(); };
+struct C { C() noexcept; ~C() noexcept(false); };
struct D: C { };
extern D d;
@@ -22,3 +22,11 @@ void *operator new(__SIZE_TYPE__, void*) noexcept;
#define SA(X) static_assert((X),#X)
SA(noexcept(new (&d) D));
+
+struct E: virtual C { };
+extern E e;
+SA(noexcept (new (&e) E));
+
+struct F { C c; };
+extern F f;
+SA(noexcept (new (&f) F));