Fix exporting a specific dynCall_* method (emscripten-core#6046)

* add a test for calling dynCall_[specific]

src/modules.js

@@ -396,6 +396,15 @@ function exportRuntime() {
     runtimeElements.push('intArrayFromBase64');
     runtimeElements.push('tryParseAsDataURI');
   }
+  // dynCall_* methods are not hardcoded here, as they
+  // depend on the file being compiled. check for them
+  // and add them.
+  for (var name in EXPORTED_RUNTIME_METHODS_SET) {
+    if (/^dynCall_/.test(name)) {
+      // a specific dynCall; add to the list
+      runtimeElements.push(name);
+    }
+  }
   var runtimeNumbers = [
     'ALLOC_NORMAL',
     'ALLOC_STACK',

tests/core/dyncall_specific.c

@@ -0,0 +1,26 @@
+#include <emscripten.h>
+
+void waka(int x, int y, int z) {
+  EM_ASM({
+    Module['print']('received ' + [$0, $1, $2] + '.');
+  }, x, y, z);
+}
+
+int main() {
+  EM_ASM({
+#if DIRECT
+    dynCall_viii($0, 1, 4, 9);
+    return;
+#endif
+#if EXPORTED
+    Module['dynCall_viii']($0, 1, 4, 9);
+    return;
+#endif
+#if FROM_OUTSIDE
+    eval("Module['dynCall_viii'](" + $0 + ", 1, 4, 9)");
+    return;
+#endif
+    throw "no test mode";
+  }, &waka);
+}
+

tests/core/dyncall_specific.txt

@@ -0,0 +1 @@
+received 1,4,9.

tests/test_core.py

@@ -5997,6 +5997,18 @@ def test_dyncall(self):
     Settings.EXTRA_EXPORTED_RUNTIME_METHODS = ['dynCall', 'addFunction']
     self.do_run_in_out_file_test('tests', 'core', 'dyncall')
 
+  def test_dyncall_specific(self):
+    emcc_args = self.emcc_args[:]
+    for which, exported_runtime_methods in [
+        ('DIRECT', []),
+        ('EXPORTED', []),
+        ('FROM_OUTSIDE', ['dynCall_viii'])
+      ]:
+      print(which)
+      self.emcc_args = emcc_args + ['-D' + which]
+      Settings.EXTRA_EXPORTED_RUNTIME_METHODS = exported_runtime_methods
+      self.do_run_in_out_file_test('tests', 'core', 'dyncall_specific')
+
   def test_getValue_setValue(self):
     # these used to be exported, but no longer are by default
     def test(output_prefix='', args=[]):