fix: remove Rvalue::Len, fix custom JSON spec file, add new needed lang items to just_main_func

Author: IntegralPilot

jvm-unknown-unknown.json.template

@@ -17,6 +17,6 @@
     "tier": 3
   },
   "panic-strategy": "abort",
-  "target-pointer-width": "32",
+  "target-pointer-width": 32,
   "llvm-target": "jvm-unknown-unknown"
 }

src/lower1/control_flow/rvalue.rs

@@ -200,26 +200,6 @@ pub fn convert_rvalue_to_operand<'a>(
             }
         }
 
-        Rvalue::Len(source_place) => {
-            let temp_len_var = generate_temp_var_name(&base_temp_name);
-            let source_name = place_to_string(source_place, tcx);
-            instructions.push(oomir::Instruction::Length {
-                dest: temp_len_var.clone(),
-                array: oomir::Operand::Variable {
-                    name: source_name,
-                    ty: ty_to_oomir_type(
-                        source_place.ty(&mir.local_decls, tcx).ty,
-                        tcx,
-                        data_types,
-                    ),
-                },
-            });
-            result_operand = oomir::Operand::Variable {
-                name: temp_len_var,
-                ty: oomir::Type::I32,
-            };
-        }
-
         Rvalue::Cast(_cast_kind, operand, target_mir_ty) => {
             let temp_cast_var = generate_temp_var_name(&base_temp_name);
             let oomir_target_type = ty_to_oomir_type(*target_mir_ty, tcx, data_types);

tests/binary/just_main_func/src/main.rs

@@ -7,4 +7,10 @@ fn main() {
 }
 
 #[lang = "sized"]
-trait Sized {}
+trait Sized {}
+
+#[lang = "meta_sized"]
+trait MetaSized {}
+
+#[lang = "pointee_sized"]
+trait PointeeSized {}