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Anna Gringauze
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Enable usage of gsl::narrow with exceptions disabled (#640)
* Enable usage of gsl::narrow with exceptions disabled This solution uses the approach of boost::asio to enabling usage of the library in environments where exception usage is either prohibited or not feasible (due to code size constraints). A function template gsl::throw_exception has been added, which in a normal environment just throws the exception. However, when GSL_TERMINATE_ON_CONTRACT_VIOLATION is defined the function is only declared by gsl and the definition of this function template must be supplied by the library's user. Closes: #468 Signed-off-by: Damian Jarek <damian.jarek93@gmail.com> Addition: - understand STL no exception macro - use function static variable to set termination handler in kernel mode - add compile-only tests for no-exception mode * added termination tests and fixed bugs * disabled warning C4577 for msvc 2015
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‎include/gsl/gsl_assert‎

Lines changed: 56 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,14 @@
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#include <exception>
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#include <stdexcept> // for logic_error
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//
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// Temporary until MSVC STL supports no-exceptions mode.
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// Currently terminate is a no-op in this mode, so we add termination behavior back
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//
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#if defined(_MSC_VER) && defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS
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#define GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND
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#endif
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//
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// There are three configuration options for this GSL implementation's behavior
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// when pre/post conditions on the GSL types are violated:
@@ -68,18 +76,62 @@ struct fail_fast : public std::logic_error
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{
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explicit fail_fast(char const* const message) : std::logic_error(message) {}
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};
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}
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namespace details
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{
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#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
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typedef void (*terminate_handler)();
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inline gsl::details::terminate_handler& get_terminate_handler() noexcept
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{
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static terminate_handler handler = &abort;
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return handler;
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}
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#endif
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[[noreturn]] inline void terminate() noexcept
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{
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#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
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(*gsl::details::get_terminate_handler())();
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#else
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std::terminate();
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#endif
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}
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#if defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
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template <typename Exception>
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[[noreturn]] void throw_exception(Exception&&)
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{
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gsl::details::terminate();
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}
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#else
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template <typename Exception>
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[[noreturn]] void throw_exception(Exception&& exception)
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{
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throw exception;
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}
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#endif
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} // namespace details
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} // namespace gsl
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#if defined(GSL_THROW_ON_CONTRACT_VIOLATION)
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#define GSL_CONTRACT_CHECK(type, cond) \
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(GSL_LIKELY(cond) ? static_cast<void>(0) \
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: throw gsl::fail_fast("GSL: " type " failure at " __FILE__ \
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": " GSL_STRINGIFY(__LINE__)))
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: gsl::details::throw_exception(gsl::fail_fast( \
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"GSL: " type " failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__))))
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#elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION)
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82-
#define GSL_CONTRACT_CHECK(type, cond) (GSL_LIKELY(cond) ? static_cast<void>(0) : std::terminate())
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#define GSL_CONTRACT_CHECK(type, cond) \
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(GSL_LIKELY(cond) ? static_cast<void>(0) : gsl::details::terminate())
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#elif defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION)
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‎include/gsl/gsl_util‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -110,9 +110,9 @@ template <class T, class U>
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T narrow(U u)
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{
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T t = narrow_cast<T>(u);
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if (static_cast<U>(t) != u) throw narrowing_error();
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if (static_cast<U>(t) != u) gsl::details::throw_exception(narrowing_error());
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if (!details::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
115-
throw narrowing_error();
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gsl::details::throw_exception(narrowing_error());
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return t;
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}
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‎tests/CMakeLists.txt‎

Lines changed: 61 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -101,3 +101,64 @@ add_gsl_test(utils_tests)
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add_gsl_test(owner_tests)
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add_gsl_test(byte_tests)
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add_gsl_test(algorithm_tests)
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# No exception tests
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foreach(flag_var
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CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
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CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
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STRING (REGEX REPLACE "/EHsc" "" ${flag_var} "${${flag_var}}")
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endforeach(flag_var)
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# this interface adds compile options to how the tests are run
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# please try to keep entries ordered =)
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add_library(gsl_tests_config_noexcept INTERFACE)
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target_compile_options(gsl_tests_config_noexcept INTERFACE
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$<$<CXX_COMPILER_ID:MSVC>:
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/D_HAS_EXCEPTIONS=0
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/wd4702
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/wd4577
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/W4
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/WX
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>
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$<$<NOT:$<CXX_COMPILER_ID:MSVC>>:
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-fno-strict-aliasing
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-fno-exceptions
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-Wall
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-Wcast-align
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-Wconversion
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-Wctor-dtor-privacy
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-Werror
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-Wextra
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-Wno-missing-braces
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-Wnon-virtual-dtor
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-Wold-style-cast
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-Woverloaded-virtual
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-Wpedantic
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-Wshadow
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-Wsign-conversion
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>
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)
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# set definitions for tests
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target_compile_definitions(gsl_tests_config_noexcept INTERFACE
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GSL_TERMINATE_ON_CONTRACT_VIOLATION
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)
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function(add_gsl_test_noexcept name)
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add_executable(${name} ${name}.cpp)
151+
target_link_libraries(${name}
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GSL
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gsl_tests_config_noexcept
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)
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add_test(
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${name}
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${name}
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)
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# group all tests under GSL_tests_noexcept
160+
set_property(TARGET ${name} PROPERTY FOLDER "GSL_tests_noexcept")
161+
endfunction()
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add_gsl_test_noexcept(no_exception_throw_tests)
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add_gsl_test_noexcept(no_exception_ensure_tests)

‎tests/no_exception_ensure_tests.cpp‎

Lines changed: 53 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,53 @@
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///////////////////////////////////////////////////////////////////////////////
2+
//
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// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
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//
5+
// This code is licensed under the MIT License (MIT).
6+
//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
8+
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
9+
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
10+
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
11+
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
12+
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
13+
// THE SOFTWARE.
14+
//
15+
///////////////////////////////////////////////////////////////////////////////
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17+
#include <cstdlib> // for std::exit
18+
#include <gsl/span> // for span
19+
20+
int operator_subscript_no_throw()
21+
{
22+
int arr[10];
23+
gsl::span<int> sp { arr };
24+
return sp[11];
25+
}
26+
27+
28+
void test_terminate()
29+
{
30+
std::exit(0);
31+
}
32+
33+
void setup_termination_handler()
34+
{
35+
#if defined(_MSC_VER)
36+
37+
auto& handler = gsl::details::get_terminate_handler();
38+
handler = &test_terminate;
39+
40+
#else
41+
42+
std::set_terminate(test_terminate);
43+
44+
#endif
45+
}
46+
47+
48+
int main()
49+
{
50+
setup_termination_handler();
51+
operator_subscript_no_throw();
52+
return -1;
53+
}

‎tests/no_exception_throw_tests.cpp‎

Lines changed: 51 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,51 @@
1+
///////////////////////////////////////////////////////////////////////////////
2+
//
3+
// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
4+
//
5+
// This code is licensed under the MIT License (MIT).
6+
//
7+
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
8+
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
9+
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
10+
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
11+
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
12+
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
13+
// THE SOFTWARE.
14+
//
15+
///////////////////////////////////////////////////////////////////////////////
16+
17+
#include <cstdlib> // for std::exit
18+
#include <gsl/gsl_util> // for narrow
19+
20+
int narrow_no_throw()
21+
{
22+
long long bigNumber = 0x0fffffffffffffff;
23+
return gsl::narrow<int>(bigNumber);
24+
}
25+
26+
void test_terminate()
27+
{
28+
std::exit(0);
29+
}
30+
31+
void setup_termination_handler()
32+
{
33+
#if defined(_MSC_VER)
34+
35+
auto& handler = gsl::details::get_terminate_handler();
36+
handler = &test_terminate;
37+
38+
#else
39+
40+
std::set_terminate(test_terminate);
41+
42+
#endif
43+
}
44+
45+
46+
int main()
47+
{
48+
setup_termination_handler();
49+
narrow_no_throw();
50+
return -1;
51+
}

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