.

Author: sbc100

src/preamble.js

@@ -428,7 +428,7 @@ function callRuntimeCallbacks(callbacks) {
     }
     var func = callback.func;
     if (typeof func === 'number') {
-      dynCallDirect(func, [callback.arg]);
+      dynCallDirect(func, callback.arg);
     } else {
       func(callback.arg === undefined ? null : callback.arg);
     }

src/preamble_minimal.js

@@ -201,9 +201,15 @@ var wasmOffsetConverter;
 #endif
 
 /** @param {Array=} args */
-function dynCallDirect(ptr, args) {
+#if ALLOW_ES6
+function dynCallDirect(ptr, ...args) {
   return wasmTable.get(ptr).apply(null, args);
 }
+#else
+function dynCallDirect(ptr) {
+  return wasmTable.get(ptr).apply(null, Array.prototype.slice.call(arguments, 1));
+}
+#endif
 
 #if EXIT_RUNTIME
 
@@ -216,7 +222,7 @@ function callRuntimeCallbacks(callbacks) {
     }
     var func = callback.func;
     if (typeof func === 'number') {
-      dynCallDirect(func, [callback.arg]);
+      dynCallDirect(func, callback.arg);
     } else {
       func(callback.arg === undefined ? null : callback.arg);
     }

src/settings.js

@@ -1611,6 +1611,9 @@ var WASM2C = 0;
 // in a custom location.
 var SEPARATE_DWARF_URL = '';
 
+// Allow ES6 constructs in the generated JS output
+var ALLOW_ES6 = 0;
+
 //===========================================
 // Internal, used for testing only, from here
 //===========================================

src/support.js

@@ -577,16 +577,16 @@ function getFuncWrapper(func, sig) {
   if (!sigCache[func]) {
     // optimize away arguments usage in common cases
     if (sig.length === 1) {
-      sigCache[func] = function() {
+      sigCache[func] = function dynCall_wrapper() {
         return dynCall(sig, func);
       };
     } else if (sig.length === 2) {
-      sigCache[func] = function(arg) {
+      sigCache[func] = function dynCall_wrapper(arg) {
         return dynCall(sig, func, [arg]);
       };
     } else {
       // general case
-      sigCache[func] = function() {
+      sigCache[func] = function dynCall_wrapper() {
         return dynCall(sig, func, Array.prototype.slice.call(arguments));
       };
     }
@@ -600,19 +600,22 @@ function makeBigInt(low, high, unsigned) {
   return unsigned ? ((+((low>>>0)))+((+((high>>>0)))*4294967296.0)) : ((+((low>>>0)))+((+((high|0)))*4294967296.0));
 }
 
-/** @param {Array=} args */
-function dynCallDirect(ptr, args) {
+#if ALLOW_ES6
+function dynCallDirect(ptr, ...args) {
   return wasmTable.get(ptr).apply(null, args);
 }
+#else
+function dynCallDirect(ptr) {
+  return wasmTable.get(ptr).apply(null, Array.prototype.slice.call(arguments, 1));
+}
+#endif
 
 /** @param {Array=} args */
 function dynCall(sig, ptr, args) {
 #if ASSERTIONS
   if (args && args.length) {
     // j (64-bit integer) must be passed in as two numbers [low 32, high 32].
     assert(args.length === sig.substring(1).replace(/j/g, '--').length);
-    // j (64-bit integer) must be passed in as two numbers [low 32, high 32].
-    assert(args.length === sig.substring(1).replace(/j/g, '--').length);
   } else {
     assert(sig.length == 1);
   }
@@ -631,7 +634,11 @@ function dynCall(sig, ptr, args) {
   }
 #endif
 
-  dynCallDirect(ptr, args);
+#if ALLOW_ES6
+  dynCallDirect(ptr, ...args);
+#else
+  dynCallDirect.apply(null, [ptr].concat(args));
+#endif
 }
 
 var tempRet0 = 0;

tools/building.py

@@ -1095,8 +1095,12 @@ def add_to_path(dirname):
       CLOSURE_EXTERNS += [path_from_root('src', 'minimal_runtime_worker_externs.js')]
     outfile = filename + '.cc.js'
 
+    if Settings.ALLOW_ES6:
+      lang = 'ECMASCRIPT6'
+    else:
+      lang = 'ECMASCRIPT5'
     args = ['--compilation_level', 'ADVANCED_OPTIMIZATIONS' if advanced else 'SIMPLE_OPTIMIZATIONS',
-            '--language_in', 'ECMASCRIPT5']
+            '--language_in', lang]
     for e in CLOSURE_EXTERNS:
       args += ['--externs', e]
     args += ['--js_output_file', outfile]
@@ -1137,7 +1141,10 @@ def add_to_path(dirname):
       logger.error(proc.stderr) # print list of errors (possibly long wall of text if input was minified)
 
       # Exit and print final hint to get clearer output
-      exit_with_error('closure compiler failed (rc: %d.%s)', proc.returncode, '' if pretty else ' the error message may be clearer with -g1 and EMCC_DEBUG=2 set')
+      msg = 'closure compiler failed (rc: %d): %s' % (proc.returncode, shared.shlex_join(cmd))
+      if not pretty:
+        msg += ' the error message may be clearer with -g1 and EMCC_DEBUG=2 set'
+      exit_with_error(msg)
 
     if len(proc.stderr.strip()) > 0 and Settings.CLOSURE_WARNINGS != 'quiet':
       # print list of warnings (possibly long wall of text if input was minified)

tools/shared.py

@@ -1229,7 +1229,7 @@ def make_invoke(sig, named=True):
         if sig[i+1] == 'j':
           new_args[i] = 'BigInt(%s)' % new_args[i]
       new_args = ','.join(new_args)
-      body = '%sdynCallDirect(index, [%s]);' % (ret, new_args)
+      body = '%sdynCallDirect(index, %s);' % (ret, new_args)
     else:
       body = '%s%s(%s);' % (ret, JS.make_dynCall(sig), args)
     # C++ exceptions are numbers, and longjmp is a string 'longjmp'