[libcxx] r220769 - [libcxx] Delay evaluation of __make_tuple_types to prevent blowing the max template instantiation depth. Fixes Bug #18345
Eric Fiselier
eric at efcs.ca
Mon Oct 27 23:31:22 PDT 2014
Author: ericwf
Date: Tue Oct 28 01:31:22 2014
New Revision: 220769
URL: http://llvm.org/viewvc/llvm-project?rev=220769&view=rev
Log:
[libcxx] Delay evaluation of __make_tuple_types to prevent blowing the max template instantiation depth. Fixes Bug #18345
Summary:
http://llvm.org/bugs/show_bug.cgi?id=18345
Tuple's constructor and assignment operators for "tuple-like" types evaluates __make_tuple_types unnecessarily. In the case of a large array this can blow the template instantiation depth.
Ex:
```
#include <array>
#include <tuple>
#include <memory>
typedef std::array<int, 1256> array_t;
typedef std::tuple<array_t> tuple_t;
int main() {
array_t a;
tuple_t t(a); // broken
t = a; // broken
// make_shared uses tuple behind the scenes. This bug breaks this code.
std::make_shared<array_t>(a);
}
```
To prevent this from happening we delay the instantiation of `__make_tuple_types` until after we perform the length check. Currently `__make_tuple_types` is instantiated at the same time that the length check .
Test Plan: Two tests have been added. One for the "tuple-like" constructors and another for the "tuple-like" assignment operator.
Reviewers: mclow.lists, EricWF
Reviewed By: EricWF
Subscribers: K-ballo, cfe-commits
Differential Revision: http://reviews.llvm.org/D4467
Added:
libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
Modified:
libcxx/trunk/include/__tuple
Modified: libcxx/trunk/include/__tuple
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__tuple?rev=220769&r1=220768&r2=220769&view=diff
==============================================================================
--- libcxx/trunk/include/__tuple (original)
+++ libcxx/trunk/include/__tuple Tue Oct 28 01:31:22 2014
@@ -245,19 +245,30 @@ struct __make_tuple_types
// __tuple_convertible
-template <bool, class _Tp, class _Up>
+template <class, class>
struct __tuple_convertible_imp : public false_type {};
template <class _Tp0, class ..._Tp, class _Up0, class ..._Up>
-struct __tuple_convertible_imp<true, __tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
+struct __tuple_convertible_imp<__tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
: public integral_constant<bool,
is_convertible<_Tp0, _Up0>::value &&
- __tuple_convertible_imp<true, __tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
+ __tuple_convertible_imp<__tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
template <>
-struct __tuple_convertible_imp<true, __tuple_types<>, __tuple_types<> >
+struct __tuple_convertible_imp<__tuple_types<>, __tuple_types<> >
: public true_type {};
+template <bool, class, class>
+struct __tuple_convertible_apply : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_convertible_apply<true, _Tp, _Up>
+ : public __tuple_convertible_imp<
+ typename __make_tuple_types<_Tp>::type
+ , typename __make_tuple_types<_Up>::type
+ >
+{};
+
template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
bool = __tuple_like<_Up>::value>
struct __tuple_convertible
@@ -265,26 +276,36 @@ struct __tuple_convertible
template <class _Tp, class _Up>
struct __tuple_convertible<_Tp, _Up, true, true>
- : public __tuple_convertible_imp<tuple_size<typename remove_reference<_Tp>::type>::value ==
- tuple_size<_Up>::value,
- typename __make_tuple_types<_Tp>::type, typename __make_tuple_types<_Up>::type>
+ : public __tuple_convertible_apply<tuple_size<typename remove_reference<_Tp>::type>::value ==
+ tuple_size<_Up>::value, _Tp, _Up>
{};
// __tuple_constructible
-template <bool, class _Tp, class _Up>
+template <class, class>
struct __tuple_constructible_imp : public false_type {};
template <class _Tp0, class ..._Tp, class _Up0, class ..._Up>
-struct __tuple_constructible_imp<true, __tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
+struct __tuple_constructible_imp<__tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
: public integral_constant<bool,
is_constructible<_Up0, _Tp0>::value &&
- __tuple_constructible_imp<true, __tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
+ __tuple_constructible_imp<__tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
template <>
-struct __tuple_constructible_imp<true, __tuple_types<>, __tuple_types<> >
+struct __tuple_constructible_imp<__tuple_types<>, __tuple_types<> >
: public true_type {};
+template <bool _SameSize, class, class>
+struct __tuple_constructible_apply : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_constructible_apply<true, _Tp, _Up>
+ : public __tuple_constructible_imp<
+ typename __make_tuple_types<_Tp>::type
+ , typename __make_tuple_types<_Up>::type
+ >
+{};
+
template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
bool = __tuple_like<_Up>::value>
struct __tuple_constructible
@@ -292,26 +313,36 @@ struct __tuple_constructible
template <class _Tp, class _Up>
struct __tuple_constructible<_Tp, _Up, true, true>
- : public __tuple_constructible_imp<tuple_size<typename remove_reference<_Tp>::type>::value ==
- tuple_size<_Up>::value,
- typename __make_tuple_types<_Tp>::type, typename __make_tuple_types<_Up>::type>
+ : public __tuple_constructible_apply<tuple_size<typename remove_reference<_Tp>::type>::value ==
+ tuple_size<_Up>::value, _Tp, _Up>
{};
// __tuple_assignable
-template <bool, class _Tp, class _Up>
+template <class, class>
struct __tuple_assignable_imp : public false_type {};
template <class _Tp0, class ..._Tp, class _Up0, class ..._Up>
-struct __tuple_assignable_imp<true, __tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
+struct __tuple_assignable_imp<__tuple_types<_Tp0, _Tp...>, __tuple_types<_Up0, _Up...> >
: public integral_constant<bool,
is_assignable<_Up0&, _Tp0>::value &&
- __tuple_assignable_imp<true, __tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
+ __tuple_assignable_imp<__tuple_types<_Tp...>, __tuple_types<_Up...> >::value> {};
template <>
-struct __tuple_assignable_imp<true, __tuple_types<>, __tuple_types<> >
+struct __tuple_assignable_imp<__tuple_types<>, __tuple_types<> >
: public true_type {};
+template <bool, class, class>
+struct __tuple_assignable_apply : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_assignable_apply<true, _Tp, _Up>
+ : __tuple_assignable_imp<
+ typename __make_tuple_types<_Tp>::type
+ , typename __make_tuple_types<_Up>::type
+ >
+{};
+
template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
bool = __tuple_like<_Up>::value>
struct __tuple_assignable
@@ -319,9 +350,8 @@ struct __tuple_assignable
template <class _Tp, class _Up>
struct __tuple_assignable<_Tp, _Up, true, true>
- : public __tuple_assignable_imp<tuple_size<typename remove_reference<_Tp>::type>::value ==
- tuple_size<_Up>::value,
- typename __make_tuple_types<_Tp>::type, typename __make_tuple_types<_Up>::type>
+ : public __tuple_assignable_apply<tuple_size<typename remove_reference<_Tp>::type>::value ==
+ tuple_size<_Up>::value, _Tp, _Up>
{};
_LIBCPP_END_NAMESPACE_STD
Added: libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp?rev=220769&view=auto
==============================================================================
--- libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp (added)
+++ libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp Tue Oct 28 01:31:22 2014
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <tuple>
+
+// template <class... Types> class tuple;
+
+// template <class Tuple, __tuple_assignable<Tuple, tuple> >
+// tuple & operator=(Tuple &&);
+
+// This test checks that we do not evaluate __make_tuple_types
+// on the array when it doesn't match the size of the tuple.
+
+#include <array>
+#include <tuple>
+
+// Use 1256 to try and blow the template instantiation depth for all compilers.
+typedef std::array<char, 1256> array_t;
+typedef std::tuple<array_t> tuple_t;
+
+int main()
+{
+ array_t arr;
+ tuple_t tup;
+ tup = arr;
+}
Added: libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp?rev=220769&view=auto
==============================================================================
--- libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp (added)
+++ libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp Tue Oct 28 01:31:22 2014
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <tuple>
+
+// template <class... Types> class tuple;
+
+// template <class Tuple, __tuple_convertible<Tuple, tuple> >
+// tuple(Tuple &&);
+//
+// template <class Tuple, __tuple_constructible<Tuple, tuple> >
+// tuple(Tuple &&);
+
+// This test checks that we do not evaluate __make_tuple_types
+// on the array.
+
+#include <array>
+#include <tuple>
+
+// Use 1256 to try and blow the template instantiation depth for all compilers.
+typedef std::array<char, 1256> array_t;
+typedef std::tuple<array_t> tuple_t;
+
+int main()
+{
+ array_t arr;
+ tuple_t tup(arr);
+}
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