From 9875869d3174cf0f15ebfccac427ade3cb01e046 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20Johan=20S=C3=B8rvig?= <morten.sorvig@qt.io>
Date: Thu, 30 Sep 2021 15:01:14 +0200
Subject: [PATCH] wasm: fix runOnMainThread()

Calling emscripten_async_run_in_main_runtime_thread_()
with a pointer to a static lambda was too clever, use
an anonymous function as callback instead.

Pick-to: 6.2
Task-number: QTBUG-94344
Change-Id: I2d8a8b0ffc2dd1d02018aa5902550216d00f641d
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
---
 src/corelib/kernel/qeventdispatcher_wasm.cpp | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/corelib/kernel/qeventdispatcher_wasm.cpp b/src/corelib/kernel/qeventdispatcher_wasm.cpp
index f5c2802aa6..c0d753c594 100644
--- a/src/corelib/kernel/qeventdispatcher_wasm.cpp
+++ b/src/corelib/kernel/qeventdispatcher_wasm.cpp
@@ -567,16 +567,20 @@ void QEventDispatcherWasm::callProcessTimers(void *context)
 }
 
 #if QT_CONFIG(thread)
-// Runs a function on the main thread
-void QEventDispatcherWasm::runOnMainThread(std::function<void(void)> fn)
-{
-    static auto trampoline = [](void *context) {
+
+namespace {
+    void trampoline(void *context) {
         std::function<void(void)> *fn = reinterpret_cast<std::function<void(void)> *>(context);
         (*fn)();
         delete fn;
-    };
+    }
+}
+
+// Runs a function on the main thread
+void QEventDispatcherWasm::runOnMainThread(std::function<void(void)> fn)
+{
     void *context = new std::function<void(void)>(fn);
-    emscripten_async_run_in_main_runtime_thread_(EM_FUNC_SIG_VI, reinterpret_cast<void *>(&trampoline), context);
+    emscripten_async_run_in_main_runtime_thread_(EM_FUNC_SIG_VI, reinterpret_cast<void *>(trampoline), context);
 }
 #endif