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[libcxx] Delay evaluation of __make_tuple_types to prevent blowing th…
…e 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 llvm-svn: 220769
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libcxx/test/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
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| Original file line number | Diff line number | Diff line change |
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| @@ -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. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
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| // <tuple> | ||
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| // template <class... Types> class tuple; | ||
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| // template <class Tuple, __tuple_assignable<Tuple, tuple> > | ||
| // tuple & operator=(Tuple &&); | ||
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| // This test checks that we do not evaluate __make_tuple_types | ||
| // on the array when it doesn't match the size of the tuple. | ||
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| #include <array> | ||
| #include <tuple> | ||
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| // 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; | ||
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| int main() | ||
| { | ||
| array_t arr; | ||
| tuple_t tup; | ||
| tup = arr; | ||
| } |
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libcxx/test/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -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. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
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| // <tuple> | ||
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| // template <class... Types> class tuple; | ||
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| // template <class Tuple, __tuple_convertible<Tuple, tuple> > | ||
| // tuple(Tuple &&); | ||
| // | ||
| // template <class Tuple, __tuple_constructible<Tuple, tuple> > | ||
| // tuple(Tuple &&); | ||
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| // This test checks that we do not evaluate __make_tuple_types | ||
| // on the array. | ||
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| #include <array> | ||
| #include <tuple> | ||
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| // 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; | ||
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| int main() | ||
| { | ||
| array_t arr; | ||
| tuple_t tup(arr); | ||
| } |