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, 90 insertions, 0 deletions

diff --git a/test/wasm2js/grow-memory-tricky.2asm.js b/test/wasm2js/grow-memory-tricky.2asm.js
new file mode 100644
index 000000000..3d5b9ec76
--- /dev/null
+++ b/test/wasm2js/grow-memory-tricky.2asm.js
@@ -0,0 +1,90 @@
+function asmFunc(global, env, buffer) {
+ "almost 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() {
+  var wasm2js_i32$0 = 0, wasm2js_i32$1 = 0;
+  wasm2js_i32$0 = 0;
+  wasm2js_i32$1 = __wasm_grow_memory(1 | 0);
+  HEAP32[wasm2js_i32$0 >> 2] = wasm2js_i32$1;
+  return HEAPU32[0 >> 2] | 0 | 0;
+ }
+ 
+ function $1() {
+  var wasm2js_i32$0 = 0, wasm2js_i32$1 = 0;
+  wasm2js_i32$0 = 0;
+  wasm2js_i32$1 = grow() | 0;
+  HEAP32[wasm2js_i32$0 >> 2] = wasm2js_i32$1;
+  return HEAPU32[0 >> 2] | 0 | 0;
+ }
+ 
+ function grow() {
+  return __wasm_grow_memory(1 | 0) | 0;
+ }
+ 
+ function __wasm_grow_memory(pagesToAdd) {
+  pagesToAdd = pagesToAdd | 0;
+  var oldPages = __wasm_current_memory() | 0;
+  var newPages = oldPages + pagesToAdd | 0;
+  if ((oldPages < newPages) && (newPages < 65535)) {
+   var newBuffer = new ArrayBuffer(Math_imul(newPages, 65536));
+   var newHEAP8 = new global.Int8Array(newBuffer);
+   newHEAP8.set(HEAP8);
+   HEAP8 = newHEAP8;
+   HEAP16 = new global.Int16Array(newBuffer);
+   HEAP32 = new global.Int32Array(newBuffer);
+   HEAPU8 = new global.Uint8Array(newBuffer);
+   HEAPU16 = new global.Uint16Array(newBuffer);
+   HEAPU32 = new global.Uint32Array(newBuffer);
+   HEAPF32 = new global.Float32Array(newBuffer);
+   HEAPF64 = new global.Float64Array(newBuffer);
+   buffer = newBuffer;
+  }
+  return oldPages;
+ }
+ 
+ function __wasm_current_memory() {
+  return buffer.byteLength / 65536 | 0;
+ }
+ 
+ return {
+  memory: Object.create(Object.prototype, {
+   grow: {
+    value: __wasm_grow_memory
+   }, 
+   buffer: {
+    get: function () {
+     return buffer;
+    }
+    
+   }
+  }), 
+  f1: $0, 
+  f2: $1
+ };
+}
+
+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);
+export const memory = retasmFunc.memory;
+export const f1 = retasmFunc.f1;
+export const f2 = retasmFunc.f2;