c5de7b113b
Summary: When using LIT the timing output is entirely unused but introduces a dependency on `<chrono>`. When libc++ is built without a montonic clock this causes some of the tests to fail. This patch factors out all of the timing logic into `support/timer.hpp` and disables it by default. To enable the timing you must define `LIBCXXABI_TIME_TESTS`. Reviewers: mclow.lists, danalbert, jroelofs Reviewed By: jroelofs Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D6391 llvm-svn: 222701
80 lines
1.9 KiB
C++
80 lines
1.9 KiB
C++
//===------------------------- dynamic_cast_stress.cpp --------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include <cassert>
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#include <tuple>
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#include "support/timer.hpp"
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template <std::size_t Indx, std::size_t Depth>
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struct C
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: public virtual C<Indx, Depth-1>,
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public virtual C<Indx+1, Depth-1>
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{
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virtual ~C() {}
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};
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template <std::size_t Indx>
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struct C<Indx, 0>
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{
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virtual ~C() {}
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};
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template <std::size_t Indx, std::size_t Depth>
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struct B
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: public virtual C<Indx, Depth-1>,
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public virtual C<Indx+1, Depth-1>
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{
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};
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template <class Indx, std::size_t Depth>
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struct makeB;
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template <std::size_t ...Indx, std::size_t Depth>
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struct makeB<std::__tuple_indices<Indx...>, Depth>
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: public B<Indx, Depth>...
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{
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};
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template <std::size_t Width, std::size_t Depth>
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struct A
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: public makeB<typename std::__make_tuple_indices<Width>::type, Depth>
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{
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};
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void test()
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{
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const std::size_t Width = 10;
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const std::size_t Depth = 5;
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A<Width, Depth> a;
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typedef B<Width/2, Depth> Destination;
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// typedef A<Width, Depth> Destination;
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Destination *b = nullptr;
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{
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timer t;
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b = dynamic_cast<Destination*>((C<Width/2, 0>*)&a);
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}
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assert(b != 0);
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}
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int main()
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{
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test();
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}
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/*
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Timing results I'm seeing (median of 3 microseconds):
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libc++abi gcc's dynamic_cast
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B<Width/2, Depth> -O3 48.334 93.190 libc++abi 93% faster
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B<Width/2, Depth> -Os 58.535 94.103 libc++abi 61% faster
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A<Width, Depth> -O3 11.515 33.134 libc++abi 188% faster
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A<Width, Depth> -Os 12.631 31.553 libc++abi 150% faster
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*/
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