From cc81618ead515a83254e362308d783a7b524bc3d Mon Sep 17 00:00:00 2001
From: FeepingCreature <feepingcreature@gmail.com>
Date: Wed, 3 Jan 2024 08:37:59 +0100
Subject: [PATCH] Communicate to llvm/gcc that refcount and index errors are
 very unlikely. Make refcount errors fatal.

---
 src/neat/runtime/array.nt |  7 +++----
 src/runtime.c             | 11 ++++++++++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/neat/runtime/array.nt b/src/neat/runtime/array.nt
index d880909b..9b395fe7 100644
--- a/src/neat/runtime/array.nt
+++ b/src/neat/runtime/array.nt
@@ -1,12 +1,11 @@
 module neat.runtime.array;
 
+extern(C) void neat_runtime_index_oob(size_t index);
+
 size_t checkIndex(size_t index, size_t length) {
     // < 0 overflows to >= length.
     if (index >= length) {
-        import neat.runtime.stdlib : exit, fprintf, stderr;
-
-        fprintf(stderr, "Array index out of bounds: %zd\n".ptr, index);
-        exit(1);
+        neat_runtime_index_oob(index);
     }
     return index;
 }
diff --git a/src/runtime.c b/src/runtime.c
index f63db61d..82c2c823 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -172,10 +172,19 @@ void print_backtrace()
 #endif
 }
 
-void neat_runtime_refcount_violation(struct String s, ptrdiff_t *ptr)
+#define FATALERROR __attribute__((cold)) __attribute__((noinline)) __attribute__((noreturn))
+
+void FATALERROR neat_runtime_refcount_violation(struct String s, ptrdiff_t *ptr)
 {
     printf("<%.*s: refcount logic violated: %zd at %p\n", (int) s.length, s.ptr, *ptr, ptr);
     print_backtrace();
+    exit(1);
+}
+
+void FATALERROR neat_runtime_index_oob(size_t index)
+{
+    fprintf(stderr, "Array index out of bounds: %zd\n", index);
+    exit(1);
 }
 
 void neat_runtime_refcount_inc(struct String s, ptrdiff_t *ptr)