litmus9.js (1650B)
1 // Tail-call litmus test with multiple results 2 // 3 // Mutually recursive functions implement a multi-entry loop using indirect tail 4 // calls, with exception handling. 5 // 6 // The functions do not have the same signatures, so if all arguments are stack 7 // arguments then these use different amounts of stack space. 8 // 9 // The "even" function will throw when the input is zero, so when an exception 10 // bubbles out of return_call it must not be caught by the exception handler in 11 // "odd", but must instead be delegated to the caller, which is JS code. 12 13 var ins = wasmEvalText(` 14 (module 15 (table 2 2 funcref) 16 (elem (i32.const 0) $even $odd) 17 (type $even_t (func (param i32) (result i32 i32 i32))) 18 (type $odd_t (func (param i32 i32) (result i32 i32 i32))) 19 (tag $t) 20 21 (func $odd (export "odd") (param $n i32) (param $dummy i32) (result i32 i32 i32) 22 try (result i32 i32 i32) 23 (if (result i32 i32 i32) (i32.eqz (local.get $n)) 24 (then (return (i32.const 0) (i32.const 32769) (i32.const -37))) 25 (else (return_call_indirect (type $even_t) (i32.sub (local.get $n) (i32.const 1)) 26 (i32.const 0)))) 27 catch_all 28 unreachable 29 end) 30 31 (func $even (export "even") (param $n i32) (result i32 i32 i32) 32 (if (result i32 i32 i32) (i32.eqz (local.get $n)) 33 (then (throw $t)) 34 (else (return_call_indirect (type $odd_t) (i32.sub (local.get $n) (i32.const 1)) (i32.const 33) 35 (i32.const 1))))) 36 ) 37 `); 38 39 assertErrorMessage(() => ins.exports.even(TailCallIterations), WebAssembly.Exception, /.*/); 40 assertSame(ins.exports.odd(TailCallIterations, 33), [0, 32769, -37]);