From 47e3a5b804eab8737a5bdeefdc4aebe0f85942c1 Mon Sep 17 00:00:00 2001
From: Piotr Wiercinski <piotr.wiercinski@qt.io>
Date: Mon, 12 May 2025 17:41:18 +0200
Subject: [PATCH] wasm: Migrate WasmSuspendResume functions from EM_JS to C++
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There is a problem with generating functions signature by Emscripten for
functions defined with EM_JS. This break dynamic linking when these
functions are imported from SIDE_MODULES.
This commit works around that issue by porting these functions to C++
which fixes their signature generation.

Task-number: QTBUG-136741
Change-Id: I3356d4dbe89b99e099d9d22327370471dc03c935
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
---
 .../wasm/qwasmsuspendresumecontrol.cpp        | 53 ++++++++++---------
 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/src/corelib/platform/wasm/qwasmsuspendresumecontrol.cpp b/src/corelib/platform/wasm/qwasmsuspendresumecontrol.cpp
index 7b71e73816b..88535a1867a 100644
--- a/src/corelib/platform/wasm/qwasmsuspendresumecontrol.cpp
+++ b/src/corelib/platform/wasm/qwasmsuspendresumecontrol.cpp
@@ -42,13 +42,15 @@ QWasmSuspendResumeControl *QWasmSuspendResumeControl::s_suspendResumeControl = n
 // Setup/constructor function for Module.suspendResumeControl.
 // FIXME if assigning to the Module object from C++ is/becomes possible
 // then this does not need to be a separate JS function.
-EM_JS(void, qtSuspendResumeControlClearJs, (), {
-    Module.qtSuspendResumeControl = {
-        resume: null,
-        eventHandlers: {},
-        pendingEvents: [],
-    };
-});
+void qtSuspendResumeControlClearJs() {
+    EM_ASM({
+        Module.qtSuspendResumeControl = ({
+            resume: null,
+            eventHandlers: {},
+            pendingEvents: [],
+        });
+    });
+}
 
 // Suspends the calling thread
 EM_ASYNC_JS(void, qtSuspendJs, (), {
@@ -60,23 +62,26 @@ EM_ASYNC_JS(void, qtSuspendJs, (), {
 // Registers a JS event handler which when called registers its index
 // as the "current" event handler, and then resumes the wasm instance.
 // The wasm instance will then call the C++ event after it is resumed.
-EM_JS(void, qtRegisterEventHandlerJs, (int index), {
-    let control = Module.qtSuspendResumeControl;
-    let handler = (arg) => {
-        control.pendingEvents.push({
-            index: index,
-            arg: arg
-        });
-        if (control.resume) {
-            const resume = control.resume;
-            control.resume = null;
-            resume();
-        } else {
-            Module.qtSendPendingEvents(); // not suspended, call the handler directly
-        }
-    };
-    control.eventHandlers[index] = handler;
-});
+void qtRegisterEventHandlerJs(int index) {
+    EM_ASM({
+        let index = $0;
+        let control = Module.qtSuspendResumeControl;
+        let handler = (arg) => {
+            control.pendingEvents.push({
+                index: index,
+                arg: arg
+            });
+            if (control.resume) {
+                const resume = control.resume;
+                control.resume = null;
+                resume();
+            } else {
+                Module.qtSendPendingEvents(); // not suspended, call the handler directly
+            }
+        };
+        control.eventHandlers[index] = handler;
+    }, index);
+}
 
 QWasmSuspendResumeControl::QWasmSuspendResumeControl()
 {