construct and destruct objects in stack allocations (alloca())

This commit is contained in:
arvidn 2017-04-27 22:54:21 -04:00 committed by Arvid Norberg
parent 2dca174785
commit 23ba9d12d1
6 changed files with 132 additions and 5 deletions

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@ -35,6 +35,43 @@ POSSIBILITY OF SUCH DAMAGE.
#include "libtorrent/config.hpp" #include "libtorrent/config.hpp"
#include "libtorrent/aux_/typed_span.hpp" #include "libtorrent/aux_/typed_span.hpp"
#include "libtorrent/aux_/numeric_cast.hpp" #include "libtorrent/aux_/numeric_cast.hpp"
#include <iterator> // for iterator_traits
#include <memory> // for addressof
namespace libtorrent { namespace aux {
template<class ForwardIt>
inline void uninitialized_default_construct(ForwardIt first, ForwardIt last)
{
using Value = typename std::iterator_traits<ForwardIt>::value_type;
ForwardIt current = first;
try {
for (; current != last; ++current) {
::new (static_cast<void*>(std::addressof(*current))) Value;
}
} catch (...) {
for (; first != current; ++first) {
first->~Value();
}
throw;
}
}
template <typename T>
struct alloca_destructor
{
span<T> objects;
~alloca_destructor()
{
for (auto& o : objects)
{
TORRENT_UNUSED(o);
o.~T();
}
}
};
}}
#if defined TORRENT_WINDOWS || defined TORRENT_MINGW #if defined TORRENT_WINDOWS || defined TORRENT_MINGW
@ -42,7 +79,10 @@ POSSIBILITY OF SUCH DAMAGE.
#define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \ #define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \
std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \ std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \
t* TORRENT_ALLOCA_tmp = static_cast<t*>(_alloca(sizeof(t) * TORRENT_ALLOCA_size)); \ t* TORRENT_ALLOCA_tmp = static_cast<t*>(_alloca(sizeof(t) * TORRENT_ALLOCA_size)); \
v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); } v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); \
::libtorrent::aux::uninitialized_default_construct(v.begin(), v.end()); \
} \
::libtorrent::aux::alloca_destructor<t> v##_destructor{v};
#elif defined TORRENT_BSD #elif defined TORRENT_BSD
@ -50,7 +90,10 @@ POSSIBILITY OF SUCH DAMAGE.
#define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \ #define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \
std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \ std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \
t* TORRENT_ALLOCA_tmp = static_cast<t*>(alloca(sizeof(t) * TORRENT_ALLOCA_size)); \ t* TORRENT_ALLOCA_tmp = static_cast<t*>(alloca(sizeof(t) * TORRENT_ALLOCA_size)); \
v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); } v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); \
::libtorrent::aux::uninitialized_default_construct(v.begin(), v.end()); \
} \
::libtorrent::aux::alloca_destructor<t> v##_destructor{v};
#else #else
@ -58,7 +101,10 @@ POSSIBILITY OF SUCH DAMAGE.
#define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \ #define TORRENT_ALLOCA(v, t, n) ::libtorrent::aux::typed_span<t> v; { \
std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \ std::size_t TORRENT_ALLOCA_size = ::libtorrent::aux::numeric_cast<std::size_t>(n); \
t* TORRENT_ALLOCA_tmp = static_cast<t*>(alloca(sizeof(t) * TORRENT_ALLOCA_size)); \ t* TORRENT_ALLOCA_tmp = static_cast<t*>(alloca(sizeof(t) * TORRENT_ALLOCA_size)); \
v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); } v = ::libtorrent::aux::typed_span<t>(TORRENT_ALLOCA_tmp, TORRENT_ALLOCA_size); \
::libtorrent::aux::uninitialized_default_construct(v.begin(), v.end()); \
} \
::libtorrent::aux::alloca_destructor<t> v##_destructor{v};
#endif #endif

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@ -102,6 +102,7 @@ namespace {
struct stack_frame struct stack_frame
{ {
stack_frame() : token(0), state(0) {}
explicit stack_frame(int const t): token(std::uint32_t(t)), state(0) {} explicit stack_frame(int const t): token(std::uint32_t(t)), state(0) {}
// this is an index into m_tokens // this is an index into m_tokens
std::uint32_t token:31; std::uint32_t token:31;

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@ -143,7 +143,8 @@ test-suite libtorrent :
test_linked_list.cpp test_linked_list.cpp
test_stack_allocator.cpp test_stack_allocator.cpp
test_listen_socket.cpp test_listen_socket.cpp
test_file_progress.cpp ] test_file_progress.cpp
test_alloca.cpp ]
[ run test_piece_picker.cpp ] [ run test_piece_picker.cpp ]

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@ -48,7 +48,8 @@ test_programs = \
test_direct_dht \ test_direct_dht \
test_ffs \ test_ffs \
test_session_params \ test_session_params \
test_span test_span \
test_alloca
if ENABLE_TESTS if ENABLE_TESTS
check_PROGRAMS = $(test_programs) check_PROGRAMS = $(test_programs)
@ -243,6 +244,7 @@ test_direct_dht_SOURCES = test_direct_dht.cpp
test_ffs_SOURCES = test_ffs.cpp test_ffs_SOURCES = test_ffs.cpp
test_session_params_SOURCES = test_session_params.cpp test_session_params_SOURCES = test_session_params.cpp
test_span_SOURCES = test_span.cpp test_span_SOURCES = test_span.cpp
test_alloca_SOURCES = test_alloca.cpp
LDADD = libtest.la $(top_builddir)/src/libtorrent-rasterbar.la LDADD = libtest.la $(top_builddir)/src/libtorrent-rasterbar.la

73
test/test_alloca.cpp Normal file
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@ -0,0 +1,73 @@
/*
Copyright (c) 2017, Arvid Norberg
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the distribution.
* Neither the name of the author nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#include "test.hpp"
#include "libtorrent/aux_/alloca.hpp"
using namespace lt;
namespace {
struct A
{
int val = 1337;
};
int destructed = 0;
struct B
{
~B() { ++destructed; }
};
}
TORRENT_TEST(alloca_construct)
{
TORRENT_ALLOCA(vec, A, 13);
TEST_EQUAL(vec.size(), 13);
for (auto const& o : vec)
{
TEST_EQUAL(o.val, 1337);
}
}
TORRENT_TEST(alloca_destruct)
{
{
destructed = 0;
TORRENT_ALLOCA(vec, B, 3);
}
TEST_EQUAL(destructed, 3);
}

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@ -33,6 +33,8 @@ POSSIBILITY OF SUCH DAMAGE.
#include "test.hpp" #include "test.hpp"
#include "libtorrent/heterogeneous_queue.hpp" #include "libtorrent/heterogeneous_queue.hpp"
namespace {
struct A struct A
{ {
int a; int a;
@ -143,6 +145,8 @@ struct G : A
std::int64_t g; std::int64_t g;
}; };
} // anonymous namespace
// test emplace_back of heterogeneous types // test emplace_back of heterogeneous types
// and retrieval of their pointers // and retrieval of their pointers
TORRENT_TEST(emplace_back) TORRENT_TEST(emplace_back)