ZJIT: Fix insn arg index for defined, add tests

Author: XrXr

zjit/bindgen/src/main.rs

@@ -368,6 +368,7 @@ fn main() {
         .allowlist_function("rb_iseqw_to_iseq")
         .allowlist_function("rb_iseq_label")
         .allowlist_function("rb_iseq_line_no")
+        .allowlist_function("rb_iseq_defined_string")
         .allowlist_type("defined_type")
 
         // From builtin.h

zjit/src/cruby_bindings.inc.rs

@@ -608,6 +608,22 @@ impl<'a> std::fmt::Display for InsnPrinter<'a> {
                 Ok(())
             },
             Insn::Snapshot { state } => write!(f, "Snapshot {}", state),
+            Insn::Defined { op_type, v, .. } => {
+                // op_type (enum defined_type) printing logic from iseq.c.
+                // Not sure why rb_iseq_defined_string() isn't exhaustive.
+                use std::borrow::Cow;
+                let op_type = *op_type as u32;
+                let op_type = if op_type == DEFINED_FUNC {
+                    Cow::Borrowed("func")
+                } else if op_type == DEFINED_REF {
+                    Cow::Borrowed("ref")
+                } else if op_type == DEFINED_CONST_FROM {
+                    Cow::Borrowed("constant-from")
+                } else {
+                    String::from_utf8_lossy(unsafe { rb_iseq_defined_string(op_type).as_rstring_byte_slice().unwrap() })
+                };
+                write!(f, "Defined {op_type}, {v}")
+            }
             Insn::DefinedIvar { self_val, id, .. } => write!(f, "DefinedIvar {self_val}, :{}", id.contents_lossy().into_owned()),
             Insn::GetIvar { self_val, id, .. } => write!(f, "GetIvar {self_val}, :{}", id.contents_lossy().into_owned()),
             Insn::SetIvar { self_val, id, val, .. } => write!(f, "SetIvar {self_val}, :{}, {val}", id.contents_lossy().into_owned()),
@@ -2152,9 +2168,10 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     state.stack_push(fun.push_insn(block, Insn::Const { val: Const::Value(VALUE::fixnum_from_usize(1)) }));
                 }
                 YARVINSN_defined => {
+                    // (rb_num_t op_type, VALUE obj, VALUE pushval)
                     let op_type = get_arg(pc, 0).as_usize();
-                    let obj = get_arg(pc, 0);
-                    let pushval = get_arg(pc, 0);
+                    let obj = get_arg(pc, 1);
+                    let pushval = get_arg(pc, 2);
                     let v = state.stack_pop()?;
                     state.stack_push(fun.push_insn(block, Insn::Defined { op_type, obj, pushval, v }));
                 }
@@ -3007,6 +3024,25 @@ mod tests {
         "#]]);
     }
 
+    #[test]
+    fn defined() {
+        eval("
+            def test = return defined?(SeaChange), defined?(favourite), defined?($ruby)
+        ");
+        assert_method_hir_with_opcodes("test", &[YARVINSN_defined], expect![[r#"
+            fn test:
+            bb0():
+              v1:NilClassExact = Const Value(nil)
+              v2:BasicObject = Defined constant, v1
+              v3:BasicObject = PutSelf
+              v4:BasicObject = Defined func, v3
+              v5:NilClassExact = Const Value(nil)
+              v6:BasicObject = Defined global-variable, v5
+              v8:ArrayExact = NewArray v2, v4, v6
+              Return v8
+        "#]]);
+    }
+
     #[test]
     fn test_return_const() {
         eval("