GSL/include/gsl/assert
Herb Sutter 1c37688ccd Replaced some of the previous workarounds with feature tests
As always with feature tests, they can only be used to aggressively adopt new features even before all compilers we need have the features -- the test lets us write a vestigial workaround for downllevel compilers, to be removed as soon as all compilers support the feature.
2020-12-18 11:20:03 -08:00

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///////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
//
// This code is licensed under the MIT License (MIT).
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef GSL_CONTRACTS_H
#define GSL_CONTRACTS_H
#include <atomic>
//
// Temporary until MSVC STL supports no-exceptions mode.
// Currently terminate is a no-op in this mode, so we add termination behavior back
//
#if defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS))
#define GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND
#include <intrin.h>
#define RANGE_CHECKS_FAILURE 0
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Winvalid-noreturn"
#endif // defined(__clang__)
#else // defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) &&
// !_HAS_EXCEPTIONS))
#include <exception>
#endif // defined(_MSC_VER) && (defined(_KERNEL_MODE) || (defined(_HAS_EXCEPTIONS) &&
// !_HAS_EXCEPTIONS))
//
// make suppress attributes parse for some compilers
// Hopefully temporary until suppression standardization occurs
//
#if defined(__clang__)
#define GSL_SUPPRESS(x) [[gsl::suppress("x")]]
#else
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
#define GSL_SUPPRESS(x) [[gsl::suppress(x)]]
#else
#define GSL_SUPPRESS(x)
#endif // _MSC_VER
#endif // __clang__
#define GSL_STRINGIFY_DETAIL(x) #x
#define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x)
//
// GSL.assert: assertions
//
namespace gsl
{
namespace details
{
#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
typedef void(__cdecl* terminate_handler)();
// clang-format off
GSL_SUPPRESS(f.6) // NO-FORMAT: attribute
// clang-format on
[[noreturn]] inline void __cdecl default_terminate_handler()
{
__fastfail(RANGE_CHECKS_FAILURE);
}
inline gsl::details::terminate_handler& get_terminate_handler() noexcept
{
static terminate_handler handler = &default_terminate_handler;
return handler;
}
#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
[[noreturn]] inline void terminate() noexcept
{
#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
(*gsl::details::get_terminate_handler())();
#else
std::terminate();
#endif // defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND)
}
} // namespace details
class contract_group {
public:
#ifdef __cpp_noexcept_function_type
using handler = void (*)() noexcept;
#else
using handler = void (*)();
#endif
contract_group (handler h) { set_handler(h); }
auto set_handler(handler h) -> handler { return chandler.exchange(h ? h : []()noexcept{}); }
auto get_handler() -> handler { return chandler; }
constexpr void expects (bool b) { assertion(b); }
constexpr void ensures (bool b) { assertion(b); }
private:
constexpr void assertion(bool b) { if (!b) chandler.load()(); }
#ifdef __cpp_guaranteed_copy_elision
std::atomic<handler> chandler; // current handler
#else
handler chandler;
#endif
};
auto static Default = contract_group( &gsl::details::terminate );
auto static Bounds = contract_group( Default.get_handler() );
auto static Null = contract_group( Default.get_handler() );
auto static Testing = contract_group( Default.get_handler() );
} // namespace gsl
#define Expects(cond, kind) kind.expects(cond)
#define Ensures(cond, kind) kind.ensures(cond)
#if defined(GSL_MSVC_USE_STL_NOEXCEPTION_WORKAROUND) && defined(__clang__)
#pragma clang diagnostic pop
#endif
#endif // GSL_CONTRACTS_H