Improve SDL_Delay and add testing. NFC (#25973)

- Cleanup implemenation of SDL_Delay
- Add testing of SDL_Timer/SDL_Delay under SDL1
- Add testing of SDL_Timer/SDL_Delay when running on pthread
- Rename test_sdl2_timer.c -> test_sdl_timer.c since it works with both
  SDL1 and SDL2
- Avoid taking the address of stack locals in test_sdl_timer.c.

Depends on #25971

Author: sbc100

src/lib/libsdl.js

@@ -1744,12 +1744,15 @@ var LibrarySDL = {
   },
 
 #if ASYNCIFY
-  SDL_Delay__deps: ['emscripten_sleep'],
-  SDL_Delay__async: true,
-  SDL_Delay: (delay) => _emscripten_sleep(delay),
+  SDL_Delay: 'emscripten_sleep',
 #else
+#if ASSERTIONS
+  SDL_Delay__deps: ['$warnOnce'],
+#endif
   SDL_Delay: (delay) => {
-    if (!ENVIRONMENT_IS_WORKER) abort('SDL_Delay called on the main thread! Potential infinite loop, quitting. (consider building with async support like ASYNCIFY)');
+#if ASSERTIONS
+    if (!ENVIRONMENT_IS_WORKER) warnOnce('SDL_Delay called on the main thread! Potential infinite loop, quitting. (consider building with async support like ASYNCIFY)');
+#endif
     // horrible busy-wait, but in a worker it at least does not block rendering
     var now = Date.now();
     while (Date.now() - now < delay) {}

test/browser/test_sdl2_timer.c test/browser/test_sdl_timer.ctest/browser/test_sdl2_timer.c renamed to test/browser/test_sdl_timer.c

@@ -8,7 +8,12 @@
 #include <assert.h>
 #include <stdio.h>
 #include <emscripten.h>
+#include <emscripten/eventloop.h>
+#ifdef USE_SDL2
+#include <SDL2/SDL.h>
+#else
 #include <SDL/SDL.h>
+#endif
 
 Uint32 start_time;
 
@@ -25,7 +30,8 @@ Uint32 SDLCALL timer_callback(Uint32 interval, void *param) {
   emscripten_force_exit(0);
 }
 
-void nop(void) {}
+int badret = 4;
+int goodret = 5;
 
 int main(int argc, char** argv) {
   SDL_Init(SDL_INIT_TIMER);
@@ -36,13 +42,16 @@ int main(int argc, char** argv) {
   // not enough ticks from busy-wait
   assert(ticks2 >= ticks1 + 4);
 
-  int badret = 4;
-  int goodret = 5;
-
   start_time = SDL_GetTicks();
   SDL_TimerID badtimer = SDL_AddTimer(500, timer_callback, &badret);
   SDL_TimerID goodtimer = SDL_AddTimer(1000, timer_callback, &goodret);
   SDL_RemoveTimer(badtimer);
 
+#if defined(USE_SDL2) && defined(_REENTRANT)
+  // When threading is enabled SDL2 uses its generic thread-based timer
+  // system.  This does not keep the runtime alive like the non-threaded (or
+  // SDL1) implementation based on emscripten_set_timeout.
+  emscripten_runtime_keepalive_push();
+#endif
   return 99;
 }

test/codesize/test_codesize_hello_dylink_all.json

@@ -1,7 +1,7 @@
 {
-  "a.out.js": 245617,
+  "a.out.js": 245482,
   "a.out.nodebug.wasm": 573657,
-  "total": 819274,
+  "total": 819139,
   "sent": [
     "IMG_Init",
     "IMG_Load",

test/test_browser.py

@@ -3055,8 +3055,13 @@ def test_sdl2_pumpevents(self):
     # key events should be detected using SDL_PumpEvents
     self.btest_exit('test_sdl2_pumpevents.c', cflags=['--pre-js', test_file('browser/fake_events.js'), '-sUSE_SDL=2'])
 
+  @also_with_proxy_to_pthread
+  def test_sdl_timer(self):
+    self.btest_exit('test_sdl_timer.c', cflags=['-sUSE_SDL'])
+
+  @also_with_proxy_to_pthread
   def test_sdl2_timer(self):
-    self.btest_exit('test_sdl2_timer.c', cflags=['-sUSE_SDL=2'])
+    self.btest_exit('test_sdl_timer.c', cflags=['-sUSE_SDL=2', '-DUSE_SDL2'])
 
   def test_sdl2_canvas_size(self):
     self.btest_exit('test_sdl2_canvas_size.c', cflags=['-sUSE_SDL=2'])