diff options
| author | Casey Carter <Casey@Carter.net> | 2017-03-20 09:30:14 -0700 |
|---|---|---|
| committer | Neil MacIntosh <neilmac@microsoft.com> | 2017-03-20 09:30:14 -0700 |
| commit | 16a6a41690325433976d843e13ec676d6f9ab091 (patch) | |
| tree | 7713646fb7ee9214e23e6931e1161b358dffdf62 /include/gsl/gsl_assert | |
| parent | 5905d2d77467d9daa18fe711b55e2db7a30fe3e3 (diff) | |
| download | Microsoft-GSL-16a6a41690325433976d843e13ec676d6f9ab091.tar.gz | |
gsl_assert changes: (#452)
* GSL_LIKELY/_UNLIKELY always contextually convert their argument to bool.
* Add macro GSL_ASSUME(cond) to inform the optimizer that the predicate cond must hold.
* Reimplement Expects & Ensures as expressions for flexibility and correctness. (Think about "if (cond1) Expects(cond2); else goto fail;")
* Expects and Ensures GSL_ASSUME their predicate when GSL_UNENFORCED_ON_CONTRACT_VIOLATION is defined.
Diffstat (limited to 'include/gsl/gsl_assert')
| -rw-r--r-- | include/gsl/gsl_assert | 50 |
1 files changed, 31 insertions, 19 deletions
diff --git a/include/gsl/gsl_assert b/include/gsl/gsl_assert index 04f34b3..1b7b810 100644 --- a/include/gsl/gsl_assert +++ b/include/gsl/gsl_assert @@ -30,20 +30,36 @@ // 2. GSL_THROW_ON_CONTRACT_VIOLATION: a gsl::fail_fast exception will be thrown // 3. GSL_UNENFORCED_ON_CONTRACT_VIOLATION: nothing happens // -#if !(defined(GSL_THROW_ON_CONTRACT_VIOLATION) || defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) || \ +#if !(defined(GSL_THROW_ON_CONTRACT_VIOLATION) || defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) || \ defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION)) -#define GSL_TERMINATE_ON_CONTRACT_VIOLATION + #define GSL_TERMINATE_ON_CONTRACT_VIOLATION #endif #define GSL_STRINGIFY_DETAIL(x) #x #define GSL_STRINGIFY(x) GSL_STRINGIFY_DETAIL(x) #if defined(__clang__) || defined(__GNUC__) -#define GSL_LIKELY(x) __builtin_expect (!!(x), 1) -#define GSL_UNLIKELY(x) __builtin_expect (!!(x), 0) + #define GSL_LIKELY(x) __builtin_expect (!!(x), 1) + #define GSL_UNLIKELY(x) __builtin_expect (!!(x), 0) #else -#define GSL_LIKELY(x) (x) -#define GSL_UNLIKELY(x) (x) + #define GSL_LIKELY(x) (!!(x)) + #define GSL_UNLIKELY(x) (!!(x)) +#endif + +// +// GSL_ASSUME(cond) +// +// Tell the optimizer that the predicate cond must hold. It is unspecified +// whether or not cond is actually evaluated. +// +#ifdef _MSC_VER + #define GSL_ASSUME(cond) __assume(cond) +#elif defined(__clang__) + #define GSL_ASSUME(cond) __builtin_assume(cond) +#elif defined(__GNUC__) + #define GSL_ASSUME(cond) ((cond) ? static_cast<void>(0) : __builtin_unreachable()) +#else + #define GSL_ASSUME(cond) static_cast<void>(!!(cond)) #endif // @@ -60,26 +76,22 @@ struct fail_fast : public std::runtime_error #if defined(GSL_THROW_ON_CONTRACT_VIOLATION) -#define Expects(cond) \ - if (GSL_UNLIKELY(!(cond))) \ - throw gsl::fail_fast("GSL: Precondition failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__)); -#define Ensures(cond) \ - if (GSL_UNLIKELY(!(cond))) \ - throw gsl::fail_fast("GSL: Postcondition failure at " __FILE__ \ - ": " GSL_STRINGIFY(__LINE__)); + #define GSL_CONTRACT_CHECK(type, cond) \ + (GSL_LIKELY(cond) ? static_cast<void>(0) : \ + throw gsl::fail_fast("GSL: " type " failure at " __FILE__ ": " GSL_STRINGIFY(__LINE__))) #elif defined(GSL_TERMINATE_ON_CONTRACT_VIOLATION) -#define Expects(cond) \ - if (GSL_UNLIKELY(!(cond))) std::terminate(); -#define Ensures(cond) \ - if (GSL_UNLIKELY(!(cond))) std::terminate(); + #define GSL_CONTRACT_CHECK(type, cond) \ + (GSL_LIKELY(cond) ? static_cast<void>(0) : std::terminate()) #elif defined(GSL_UNENFORCED_ON_CONTRACT_VIOLATION) -#define Expects(cond) -#define Ensures(cond) + #define GSL_CONTRACT_CHECK(type, cond) GSL_ASSUME(cond) #endif +#define Expects(cond) GSL_CONTRACT_CHECK("Precondition", cond) +#define Ensures(cond) GSL_CONTRACT_CHECK("Postcondition", cond) + #endif // GSL_CONTRACTS_H |