MicroJIT: Don't compile trace instructions

iseq.c

@@ -3232,6 +3232,25 @@ rb_vm_insn_addr2insn(const void *addr)
     rb_bug("rb_vm_insn_addr2insn: invalid insn address: %p", addr);
 }
 
+// Unlike rb_vm_insn_addr2insn, this function can return trace opcode variants.
+int
+rb_vm_insn_addr2opcode(const void *addr)
+{
+    st_data_t key = (st_data_t)addr;
+    st_data_t val;
+
+    if (st_lookup(rb_encoded_insn_data, key, &val)) {
+        insn_data_t *e = (insn_data_t *)val;
+        int opcode = e->insn;
+        if (addr == e->trace_encoded_insn) {
+            opcode += VM_INSTRUCTION_SIZE/2;
+        }
+        return opcode;
+    }
+
+    rb_bug("rb_vm_insn_addr2opcode: invalid insn address: %p", addr);
+}
+
 // Decode `iseq->body->iseq_encoded[i]` to an insn.
 int
 rb_vm_insn_decode(const VALUE encoded)

iseq.h

@@ -167,6 +167,8 @@ const rb_iseq_t *rb_iseq_load_iseq(VALUE fname);
 unsigned int *rb_iseq_insns_info_decode_positions(const struct rb_iseq_constant_body *body);
 #endif
 
+int rb_vm_insn_addr2opcode(const void *addr);
+
 RUBY_SYMBOL_EXPORT_BEGIN
 
 /* compile.c */

ujit_compile.c

@@ -74,7 +74,7 @@ opcode_at_pc(const rb_iseq_t *iseq, const VALUE *pc)
 {
     const VALUE at_pc = *pc;
     if (FL_TEST_RAW((VALUE)iseq, ISEQ_TRANSLATED)) {
-        return rb_vm_insn_addr2insn((const void *)at_pc);
+        return rb_vm_insn_addr2opcode((const void *)at_pc);
     }
     else {
         return (int)at_pc;