fix i64* funcs in side modules when only some are used

src/jsifier.js

@@ -16,6 +16,8 @@ var INDENTATION = ' ';
 
 var functionStubSigs = {};
 
+var ALWAYS_EMITTED_I64_FUNCS = set('i64Add', 'i64Subtract', 'bitshift64Shl', 'bitshift64Lshr', 'bitshift64Ashr'); // even in side modules
+
 // JSifier
 function JSify(data, functionsOnly) {
   //B.start('jsifier');
@@ -137,6 +139,7 @@ function JSify(data, functionsOnly) {
           LibraryManager.library[shortident] = new Function("Module['printErr']('missing function: " + shortident + "'); abort(-1);");
         } else {
           var target = (MAIN_MODULE ? '' : 'parent') + "Module['_" + shortident + "']";
+          if (SIDE_MODULE && (ident in ALWAYS_EMITTED_I64_FUNCS)) return ''; // we emit i64Add etc. even in side modules (small, and should be fast)
           var assertion = '';
           if (ASSERTIONS) assertion = 'if (!' + target + ') abort("external function \'' + shortident + '\' is missing. perhaps a side module was not linked in? if this function was expected to arrive from a system library, try to build the MAIN_MODULE with EMCC_FORCE_STDLIBS=1 in the environment");';
           LibraryManager.library[shortident] = new Function(assertion + "return " + target + ".apply(null, arguments);");

tests/test_core.py

@@ -3934,6 +3934,25 @@ var Module = {
       }
     ''', 'other says 15724949027125.')
 
+  def test_dylink_i64_b(self):
+    self.dylink_test('''
+      #include <stdio.h>
+      #include <stdint.h>
+      extern int64_t sidey();
+      int main() {
+        printf("other says %lld.", sidey());
+        return 0;
+      }
+    ''', '''
+      #include <stdint.h>
+      int64_t sidey() {
+        volatile int64_t x = 0x12345678abcdef12LL;
+        x += x % 17;
+        x = 18 - x;
+        return x;
+      }
+    ''', 'other says -1311768467750121224.')
+
   def test_dylink_class(self):
     self.dylink_test(header=r'''
       #include <stdio.h>