Rename `wasm2asm` to `wasm2js`, emit ESM by default (#1642)

* Rename the `wasm2asm` tool to `wasm2js`

This commit performs a relatively simple rename of the `wasm2asm` tool to
`wasm2js`. The functionality of the tool doesn't change just yet but it's
intended that we'll start generating an ES module instead of just an `asm.js`
function soon.

* wasm2js: Support `*.wasm` input files

Previously `wasm2js` only supported `*.wast` files but to make it a bit easier
to use in tooling pipelines this commit adds support for reading in a `*.wasm`
file directly. Determining which parser to use depends on the input filename,
where the binary parser is used with `*.wasm` files and the wast parser is used
for all other files.

* wasm2js: Emit ESM imports/exports by default

This commit alters the default behavior of `wasm2js` to emit an ESM by default,
either importing items from the environment or exporting. Items like
initialization of memory are also handled here.

1 files changed, 99 insertions, 0 deletions

diff --git a/test/wasm2js.asserts.js b/test/wasm2js.asserts.js
new file mode 100644
index 000000000..b097a5aaa
--- /dev/null
+++ b/test/wasm2js.asserts.js
@@ -0,0 +1,99 @@
+function asmFunc(global, env, buffer) {
+ "use asm";
+ var HEAP8 = new global.Int8Array(buffer);
+ var HEAP16 = new global.Int16Array(buffer);
+ var HEAP32 = new global.Int32Array(buffer);
+ var HEAPU8 = new global.Uint8Array(buffer);
+ var HEAPU16 = new global.Uint16Array(buffer);
+ var HEAPU32 = new global.Uint32Array(buffer);
+ var HEAPF32 = new global.Float32Array(buffer);
+ var HEAPF64 = new global.Float64Array(buffer);
+ var Math_imul = global.Math.imul;
+ var Math_fround = global.Math.fround;
+ var Math_abs = global.Math.abs;
+ var Math_clz32 = global.Math.clz32;
+ var Math_min = global.Math.min;
+ var Math_max = global.Math.max;
+ var Math_floor = global.Math.floor;
+ var Math_ceil = global.Math.ceil;
+ var Math_sqrt = global.Math.sqrt;
+ var abort = env.abort;
+ var nan = global.NaN;
+ var infinity = global.Infinity;
+ var i64toi32_i32$HIGH_BITS = 0;
+ function $0() {
+  
+ }
+ 
+ function $1(x, y) {
+  x = x | 0;
+  y = y | 0;
+  return x + y | 0 | 0;
+ }
+ 
+ function $2(x, y) {
+  x = x | 0;
+  y = y | 0;
+  return (x | 0) / (y | 0) | 0 | 0;
+ }
+ 
+ function __wasm_fetch_high_bits() {
+  return i64toi32_i32$HIGH_BITS | 0;
+ }
+ 
+ return {
+  empty: $0, 
+  add: $1, 
+  div_s: $2, 
+  __wasm_fetch_high_bits: __wasm_fetch_high_bits
+ };
+}
+
+const memasmFunc = new ArrayBuffer(65536);
+const retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
+
+      var nan = NaN;
+      var infinity = Infinity;
+    ;
+
+      function f32Equal(a, b) {
+         var i = new Int32Array(1);
+         var f = new Float32Array(i.buffer);
+         f[0] = a;
+         var ai = f[0];
+         f[0] = b;
+         var bi = f[0];
+
+         return (isNaN(a) && isNaN(b)) || a == b;
+      }
+
+      function f64Equal(a, b) {
+         var i = new Int32Array(2);
+         var f = new Float64Array(i.buffer);
+         f[0] = a;
+         var ai1 = i[0];
+         var ai2 = i[1];
+         f[0] = b;
+         var bi1 = i[0];
+         var bi2 = i[1];
+
+         return (isNaN(a) && isNaN(b)) || (ai1 == bi1 && ai2 == bi2);
+      }
+
+      function i64Equal(actual_lo, actual_hi, expected_lo, expected_hi) {
+         return actual_lo == (expected_lo | 0) && actual_hi == (expected_hi | 0);
+      }
+    ;
+function check1() {
+ var wasm2js_i32$0 = 0;
+ retasmFunc.empty();
+ wasm2js_i32$0 = 1;
+ return wasm2js_i32$0 | 0;
+}
+
+if (!check1()) fail1();
+function check2() {
+ return (retasmFunc.add(1 | 0, 1 | 0) | 0 | 0) == (2 | 0) | 0;
+}
+
+if (!check2()) fail2();