From 3d2e3e87f6a861e0aad29b3910467817c0655923 Mon Sep 17 00:00:00 2001
From: Davide Bettio <davide@uninstall.it>
Date: Tue, 25 Jul 2023 00:03:12 +0200
Subject: [PATCH] utils: add UNREACHABLE() macro

Instead of directly using GCC builtin __builtin_unreachable() define and use
UNREACHABLE() macro.

Signed-off-by: Davide Bettio <davide@uninstall.it>
---
 src/libAtomVM/nifs.c          | 2 +-
 src/libAtomVM/opcodesswitch.h | 6 +++---
 src/libAtomVM/utils.h         | 7 +++++++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/libAtomVM/nifs.c b/src/libAtomVM/nifs.c
index e59705765..56efc1abd 100644
--- a/src/libAtomVM/nifs.c
+++ b/src/libAtomVM/nifs.c
@@ -3465,7 +3465,7 @@ static term open_avm_error_tuple(Context *ctx, enum OpenAVMResult result)
             reason = globalcontext_make_atom(ctx->global, ATOM_STR("\xD", "not_supported"));
             break;
         case AVM_OPEN_OK:
-            __builtin_unreachable();
+            UNREACHABLE();
     }
     if (UNLIKELY(memory_ensure_free(ctx, TUPLE_SIZE(2)) != MEMORY_GC_OK)) {
         RAISE_ERROR(OUT_OF_MEMORY_ATOM);
diff --git a/src/libAtomVM/opcodesswitch.h b/src/libAtomVM/opcodesswitch.h
index b190736f9..c1be579c2 100644
--- a/src/libAtomVM/opcodesswitch.h
+++ b/src/libAtomVM/opcodesswitch.h
@@ -295,7 +295,7 @@ typedef union
             off += 1 + sz;                                                                          \
             break;                                                                                  \
         }                                                                                           \
-        default: __builtin_unreachable(); /* help gcc 8.4 */                                        \
+        default: UNREACHABLE(); /* help gcc 8.4 */                                                  \
     }                                                                                               \
 }
 
@@ -626,7 +626,7 @@ typedef union
             off += 1 + sz;                                                                          \
             break;                                                                                  \
         }                                                                                           \
-        default: __builtin_unreachable(); /* help gcc 8.4 */                                        \
+        default: UNREACHABLE(); /* help gcc 8.4 */                                                  \
     }                                                                                               \
 }
 
@@ -754,7 +754,7 @@ typedef union
                     break;                                                                      \
                 }                                                                               \
                 case NormalMessage: {                                                           \
-                    __builtin_unreachable();                                                    \
+                    UNREACHABLE();                                                              \
                 }                                                                               \
             }                                                                                   \
             MailboxMessage *next = signal_message->next;                                        \
diff --git a/src/libAtomVM/utils.h b/src/libAtomVM/utils.h
index e4eb6150e..260adccfd 100644
--- a/src/libAtomVM/utils.h
+++ b/src/libAtomVM/utils.h
@@ -259,4 +259,11 @@ static inline __attribute__((always_inline)) void *cast_func_to_void_ptr(func_pt
     #define NO_DISCARD(...)
 #endif
 
+#ifdef __GNUC__
+    #define UNREACHABLE() \
+        __builtin_unreachable()
+#else
+    #define UNREACHABLE(...)
+#endif
+
 #endif