From f5938583a72551e5dbe94768a5fc884ebc2c0171 Mon Sep 17 00:00:00 2001
From: Brady <zeromemesdev@gmail.com>
Date: Thu, 1 Aug 2024 14:17:51 -0500
Subject: [PATCH] Add `LIBHAT_UNREACHABLE` macro

---
 include/libhat/Defines.hpp | 17 +++++++++++++++++
 include/libhat/Scanner.hpp |  2 +-
 src/arch/x86/AVX2.cpp      |  2 +-
 src/arch/x86/AVX512.cpp    |  2 +-
 src/arch/x86/SSE.cpp       |  2 +-
 5 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/libhat/Defines.hpp b/include/libhat/Defines.hpp
index 328ce99..aebeabc 100644
--- a/include/libhat/Defines.hpp
+++ b/include/libhat/Defines.hpp
@@ -73,3 +73,20 @@
 #else
     #define LIBHAT_UNLIKELY
 #endif
+
+#if __cpp_lib_unreachable >= 202202L
+    #include <utility>
+    #define LIBHAT_UNREACHABLE() std::unreachable()
+#elif defined(_MSC_VER)
+    #define LIBHAT_UNREACHABLE() __assume(false)
+#elif defined(__GNUC__)
+    #define LIBHAT_UNREACHABLE() __builtin_unreachable()
+#else
+    #include <cstdlib>
+    namespace hat::detail {
+        [[noreturn]] inline void unreachable_impl() {
+            std::abort();
+        }
+    }
+    #define LIBHAT_UNREACHABLE() hat::detail::unreachable_impl()
+#endif
diff --git a/include/libhat/Scanner.hpp b/include/libhat/Scanner.hpp
index 8f3d883..818fdc4 100644
--- a/include/libhat/Scanner.hpp
+++ b/include/libhat/Scanner.hpp
@@ -211,7 +211,7 @@ namespace hat {
                 case scan_alignment::X1: return &find_pattern_single<scan_alignment::X1>;
                 case scan_alignment::X16: return &find_pattern_single<scan_alignment::X16>;
             }
-            std::unreachable();
+            LIBHAT_UNREACHABLE();
         }
 
         [[nodiscard]] constexpr auto truncate(const signature_view signature) noexcept {
diff --git a/src/arch/x86/AVX2.cpp b/src/arch/x86/AVX2.cpp
index 17fb134..22c7d30 100644
--- a/src/arch/x86/AVX2.cpp
+++ b/src/arch/x86/AVX2.cpp
@@ -117,7 +117,7 @@ namespace hat::detail {
                 return &find_pattern_avx2<scan_alignment::X16, false, false>;
             }
         }
-        std::unreachable();
+        LIBHAT_UNREACHABLE();
     }
 }
 #endif
diff --git a/src/arch/x86/AVX512.cpp b/src/arch/x86/AVX512.cpp
index 6c7a7f1..4585240 100644
--- a/src/arch/x86/AVX512.cpp
+++ b/src/arch/x86/AVX512.cpp
@@ -112,7 +112,7 @@ namespace hat::detail {
                 return &find_pattern_avx512<scan_alignment::X16, false, false>;
             }
         }
-        std::unreachable();
+        LIBHAT_UNREACHABLE();
     }
 }
 #endif
diff --git a/src/arch/x86/SSE.cpp b/src/arch/x86/SSE.cpp
index 7540707..146543f 100644
--- a/src/arch/x86/SSE.cpp
+++ b/src/arch/x86/SSE.cpp
@@ -115,7 +115,7 @@ namespace hat::detail {
                 return &find_pattern_sse<scan_alignment::X16, false, false>;
             }
         }
-        std::unreachable();
+        LIBHAT_UNREACHABLE();
     }
 }
 #endif