ZJIT: Fix kwargs handling in invokeblock ifunc specialization (#17971)

gen_invokeblock_ifunc drops the callinfo and passes argv straight to
rb_vm_yield_with_cfunc, which hardcodes kw_splat = 0, so keyword
arguments lost their keyword-ness. Gate the ifunc specialization on
block_call_inlinable, the same check used for the inline ISEQ path.

zjit/src/codegen_tests.rs

@@ -6012,6 +6012,18 @@ fn test_invokeblock_ifunc_map() {
     assert_snapshot!(assert_compiles("test"), @"[2, 4, 6]");
 }
 
+#[test]
+fn test_invokeblock_ifunc_kwarg() {
+    eval("
+        def foo
+          yield 1, a: 2
+        end
+        def test = enum_for(:foo).to_a
+        test
+    ");
+    assert_snapshot!(assert_compiles("test"), @"[[1, {a: 2}]]");
+}
+
 #[test]
 fn test_ccall_variadic_with_multiple_args() {
     eval("

zjit/src/hir.rs

@@ -9326,7 +9326,7 @@ fn add_iseq_to_hir(
                         Some(summary.bucket(0).class())
                     });
 
-                    let is_ifunc = (flags & (VM_CALL_ARGS_SPLAT | VM_CALL_KW_SPLAT)) == 0
+                    let is_ifunc = (flags & (VM_CALL_ARGS_SPLAT | VM_CALL_KW_SPLAT | VM_CALL_KWARG)) == 0
                         && block_handler_class.is_some_and(|obj| unsafe { rb_IMEMO_TYPE_P(obj, imemo_ifunc) == 1 });
 
                     // If the block handler is a known simple ISEQ block with exact arity and no

zjit/src/hir/opt_tests.rs

@@ -17913,6 +17913,34 @@ mod hir_opt_tests {
         ");
     }
 
+    #[test]
+    fn test_invokeblock_ifunc_kwarg() {
+        eval("
+            def foo
+              yield 1, a: 2
+            end
+            def test = enum_for(:foo).to_a
+            test
+        ");
+        assert_snapshot!(hir_string("foo"), @"
+        fn foo@<compiled>:3:
+        bb1():
+          EntryPoint interpreter
+          v1:BasicObject = LoadSelf
+          Jump bb3(v1)
+        bb2():
+          EntryPoint JIT(0)
+          v4:BasicObject = LoadArg :self@0
+          Jump bb3(v4)
+        bb3(v6:BasicObject):
+          v10:Fixnum[1] = Const Value(1)
+          v12:Fixnum[2] = Const Value(2)
+          v14:BasicObject = InvokeBlock v10, v12 # SendFallbackReason: InvokeBlock: not yet specialized
+          CheckInterrupts
+          Return v14
+        ");
+    }
+
     #[test]
     fn test_dedup_guard_type() {
         // Two subtractions on the same Fixnum operand `n` each require a