Refactor jit_func_t and jit_exec

I closed https://github.com/ruby/ruby/pull/7543, but part of the diff
seems useful regardless, so I extracted it.

1 files changed, 8 insertions, 0 deletions

diff --git a/vm_exec.h b/vm_exec.h
index 361516e86b..a00bd5027c 100644
--- a/vm_exec.h
+++ b/vm_exec.h
@@ -174,6 +174,14 @@ default:                        \
 #define THROW_EXCEPTION(exc) return (VALUE)(exc)
 #endif
 
+#define JIT_EXEC(ec, val) do { \
+    rb_jit_func_t func; \
+    if (val == Qundef && (func = jit_compile(ec))) { \
+        val = func(ec, ec->cfp); \
+        if (ec->tag->state) THROW_EXCEPTION(val); \
+    } \
+} while (0)
+
 #define SCREG(r) (reg_##r)
 
 #define VM_DEBUG_STACKOVERFLOW 0