Avoid using WasmOffsetConverter when Module.instantiateWasm (#13425)

Module.instantiateWasm is a callback the user provides, and then the user is
in change of fetching and instantiating the wasm. In that code path emscripten
never sees the wasm binary, which means we cannot create a
WasmOffsetConverter.

With this PR we will not hang on startup, and we will still detect problems, but
the sanitizer's own stack traces will mark function names as "unknown". That will
limit the santizer's usefulness, but they do still detect errors, and the browser's
own stack traces may be enough to diagnose things.

Fixes #13424

Author: kripken

src/preamble.js

@@ -1120,6 +1120,24 @@ function createWasm() {
       var exports = Module['instantiateWasm'](info, receiveInstance);
 #if ASYNCIFY
       exports = Asyncify.instrumentWasmExports(exports);
+#endif
+#if USE_OFFSET_CONVERTER
+      {{{
+        runOnMainThread(`
+          // We have no way to create an OffsetConverter in this code path since
+          // we have no access to the wasm binary (only the user does). Instead,
+          // create a fake one that reports we cannot identify functions from
+          // their binary offsets.
+          // Note that we only do this on the main thread, as the workers
+          // receive the OffsetConverter data from there.
+          wasmOffsetConverter = {
+            getName: function() {
+              return 'unknown-due-to-instantiateWasm';
+            }
+          };
+          removeRunDependency('offset-converter');
+        `)
+      }}}
 #endif
       return exports;
     } catch(e) {

tests/test_browser.py

@@ -4155,8 +4155,12 @@ def test_binaryen_async(self):
     self.btest_exit('binaryen_async.c', expected=1, args=common_args)
 
   # Test that implementing Module.instantiateWasm() callback works.
-  def test_manual_wasm_instantiate(self):
-    self.compile_btest([path_from_root('tests/manual_wasm_instantiate.cpp'), '-o', 'manual_wasm_instantiate.js', '-s', 'BINARYEN'])
+  @parameterized({
+    '': ([],),
+    'asan': (['-fsanitize=address', '-s', 'INITIAL_MEMORY=128MB'],)
+  })
+  def test_manual_wasm_instantiate(self, args=[]):
+    self.compile_btest([path_from_root('tests/manual_wasm_instantiate.cpp'), '-o', 'manual_wasm_instantiate.js'] + args)
     shutil.copyfile(path_from_root('tests', 'manual_wasm_instantiate.html'), 'manual_wasm_instantiate.html')
     self.run_browser('manual_wasm_instantiate.html', 'wasm instantiation succeeded', '/report_result?1')