utility: Add function to signal code is unreachable

meson.build

@@ -60,6 +60,8 @@ extended_warnings = [
 	'-Wstack-protector',
 	'-Wunsuffixed-float-constant',
 	'-Wimplicit-fallthrough',
+	'-Werror=switch',
+	'-we4061' # enumerator 'identifier' in switch of enum 'enumeration' is not explicitly handled by a case label
 ]
 
 add_project_arguments(

substrate/internal/defs

@@ -137,5 +137,13 @@
 #define SUBSTRATE_INTERFACE
 #endif
 
+#if defined(_MSC_VER) && !defined(__clang__)
+#define SUBSTRATE_ALWAYS_INLINE __forceinline
+#elif defined(__has_attribute) && __has_attribute(always_inline)
+#define SUBSTRATE_ALWAYS_INLINE inline __attribute__((always_inline))
+#else
+#define SUBSTRATE_ALWAYS_INLINE inline
+#endif
+
 #endif /* SUBSTRATE_INTERNAL_DEFS */
 /* vim: set ft=cpp ts=4 sw=4 noexpandtab: */

substrate/utility

@@ -8,7 +8,6 @@
 #include <array>
 #include <memory>
 #include <string>
-#include <limits>
 #include <vector>
 #include <chrono>
 #include <utility>
@@ -784,7 +783,26 @@ namespace substrate
 	template<typename C> SUBSTRATE_NO_DISCARD(inline SUBSTRATE_CXX14_CONSTEXPR auto data(const C &c)) -> decltype(c.data()) { return c.data(); }
 	template<typename T, std::size_t N> SUBSTRATE_NO_DISCARD(inline SUBSTRATE_CXX14_CONSTEXPR T *data(T (&array)[N]) noexcept) { return array; }
 	template<typename E> SUBSTRATE_NO_DISCARD(inline SUBSTRATE_CXX14_CONSTEXPR const E *data(std::initializer_list<E> il) noexcept) { return il.begin(); }
+#endif 
+
+#if defined(_MSC_VER)
+#	pragma warning(disable:4702) // abort is unreachable code
+#endif
+[[noreturn]] SUBSTRATE_ALWAYS_INLINE void unreachable()
+{
+#if defined(_MSC_VER) && !defined(__clang__)
+	__assume(false);
+#else
+	__builtin_unreachable();
 #endif
+#ifdef _DEBUG
+	abort();
+#endif
+}
+#if defined(_MSC_VER)
+#	pragma warning(default:4702)
+#endif
+
 } // namespace substrate
 
 #endif /* SUBSTRATE_UTILITIES */