Function aliases

cranelift/codegen/src/write.rs:683–716

()

    #[test]
    fn aliases() {
        use crate::ir::InstBuilder;

        let mut func = Function::new();
        {
            let block0 = func.dfg.make_block();
            let mut pos = FuncCursor::new(&mut func);
            pos.insert_block(block0);

            // make some detached values for change_to_alias
            let v0 = pos.func.dfg.append_block_param(block0, types::I32);
            let v1 = pos.func.dfg.append_block_param(block0, types::I32);
            let v2 = pos.func.dfg.append_block_param(block0, types::I32);
            pos.func.dfg.detach_block_params(block0);

            // alias to a param--will be printed at beginning of block defining param
            let v3 = pos.func.dfg.append_block_param(block0, types::I32);
            pos.func.dfg.change_to_alias(v0, v3);

            // alias to an alias--should print attached to alias, not ultimate target
            pos.func.dfg.make_value_alias_for_serialization(v0, v2); // v0 <- v2

            // alias to a result--will be printed after instruction producing result
            let _dummy0 = pos.ins().iconst(types::I32, 42);
            let v4 = pos.ins().iadd(v0, v0);
            pos.func.dfg.change_to_alias(v1, v4);
            let _dummy1 = pos.ins().iconst(types::I32, 23);
            let _v7 = pos.ins().iadd(v1, v1);
        }
        assert_eq!(
            func.to_string(),
            "function u0:0() fast {\nblock0(v3: i32):\n    v0 -> v3\n    v2 -> v0\n    v4 = iconst.i32 42\n    v5 = iadd v0, v0\n    v1 -> v5\n    v6 = iconst.i32 23\n    v7 = iadd v1, v1\n}\n"
        );
    }

    #[test]
    fn cold_blocks() {