Multithreading 29/N: Backproxying

emscripten-version.txt

@@ -1 +1 @@
-"1.38.14"
+"1.38.15"

src/library_pthread.js

@@ -171,7 +171,7 @@ var LibraryPThread = {
           }
           if (transferList.length > 0) {
             postMessage({
-                targetThread: parentThreadId,
+                targetThread: _emscripten_main_browser_thread_id(),
                 cmd: 'objectTransfer',
                 offscreenCanvases: offscreenCanvases,
                 moduleCanvasId: Module['canvas'].id, // moduleCanvasId specifies which canvas is denoted via the "#canvas" shorthand.
@@ -269,12 +269,13 @@ var LibraryPThread = {
         (function(worker) {
           worker.onmessage = function(e) {
             var d = e.data;
+            // Sometimes we need to backproxy events to the calling thread (e.g. HTML5 DOM events handlers such as emscripten_set_mousemove_callback()), so keep track in a globally accessible variable about the thread that initiated the proxying.
+            if (worker.pthread) PThread.currentProxiedOperationCallerThread = worker.pthread.threadInfoStruct;
             // TODO: Move the proxied call mechanism into a queue inside heap.
             if (d.proxiedCall) {
               var returnValue;
               var funcTable = (d.func >= 0) ? proxiedFunctionTable : ASM_CONSTS;
               var funcIdx = (d.func >= 0) ? d.func : (-1 - d.func);
-              PThread.currentProxiedOperationCallerThread = worker.pthread.threadInfoStruct; // Sometimes we need to backproxy events to the calling thread (e.g. HTML5 DOM events handlers such as emscripten_set_mousemove_callback()), so keep track in a globally accessible variable about the thread that initiated the proxying.
               switch(d.proxiedCall & 31) {
                 case 1: returnValue = funcTable[funcIdx](); break;
                 case 2: returnValue = funcTable[funcIdx](d.p0); break;
@@ -302,6 +303,7 @@ var LibraryPThread = {
                 Atomics.store(HEAP32, waitAddress >> 2, 1);
                 Atomics.wake(HEAP32, waitAddress >> 2, 1);
               }
+              PThread.currentProxiedOperationCallerThread = undefined;
               return;
             }
 
@@ -313,6 +315,7 @@ var LibraryPThread = {
               } else {
                 console.error('Internal error! Worker sent a message "' + d.cmd + '" to target pthread ' + d.targetThread + ', but that thread no longer exists!');
               }
+              PThread.currentProxiedOperationCallerThread = undefined;
               return;
             }
 
@@ -345,7 +348,11 @@ var LibraryPThread = {
             } else if (d.cmd === 'alert') {
               alert('Thread ' + d.threadId + ': ' + d.text);
             } else if (d.cmd === 'exit') {
-              // currently no-op
+              // Thread is exiting, no-op here
+            } else if (d.cmd === 'exitProcess') {
+              // A pthread has requested to exit the whole application process (runtime).
+              Module['noExitRuntime'] = false;
+              exit(d.returnCode);
             } else if (d.cmd === 'cancelDone') {
               PThread.freeThreadData(worker.pthread);
               worker.pthread = undefined; // Detach the worker from the pthread object, and return it to the worker pool as an unused worker.
@@ -359,6 +366,7 @@ var LibraryPThread = {
             } else {
               err("worker sent an unknown command " + d.cmd);
             }
+            PThread.currentProxiedOperationCallerThread = undefined;
           };
 
           worker.onerror = function(e) {
@@ -621,7 +629,10 @@ var LibraryPThread = {
       if (inheritSched) {
         var prevSchedPolicy = {{{ makeGetValue('attr', 20/*_a_policy*/, 'i32') }}};
         var prevSchedPrio = {{{ makeGetValue('attr', 24/*_a_prio*/, 'i32') }}};
-        _pthread_getschedparam(_pthread_self(), attr + 20, attr + 24);
+        // If we are inheriting the scheduling properties from the parent thread, we need to identify the parent thread properly - this function call may
+        // be getting proxied, in which case _pthread_self() will point to the thread performing the proxying, not the thread that initiated the call.
+        var parentThreadPtr = PThread.currentProxiedOperationCallerThread ? PThread.currentProxiedOperationCallerThread : _pthread_self();
+        _pthread_getschedparam(parentThreadPtr, attr + 20, attr + 24);
         schedPolicy = {{{ makeGetValue('attr', 20/*_a_policy*/, 'i32') }}};
         schedPrio = {{{ makeGetValue('attr', 24/*_a_prio*/, 'i32') }}};
         {{{ makeSetValue('attr', 20/*_a_policy*/, 'prevSchedPolicy', 'i32') }}};

src/library_pthread_stub.js

@@ -218,6 +218,9 @@ var LibraryPThreadStub = {
   sem_trywait: function() {},
   sem_destroy: function() {},
 
+  emscripten_main_browser_thread_id__deps: ['pthread_self'],
+  emscripten_main_browser_thread_id: function() { return _pthread_self(); },
+
   // When pthreads is not enabled, we can't use the Atomics futex api to do proper sleeps, so simulate a busy spin wait loop instead.
   usleep: function(useconds) {
     // int usleep(useconds_t useconds);

src/preamble.js

@@ -1600,6 +1600,7 @@ function ensureInitRuntime() {
 #if USE_PTHREADS
   // Pass the thread address inside the asm.js scope to store it for fast access that avoids the need for a FFI out.
   __register_pthread_ptr(PThread.mainThreadBlock, /*isMainBrowserThread=*/!ENVIRONMENT_IS_WORKER, /*isMainRuntimeThread=*/1);
+  _emscripten_register_main_browser_thread_id(PThread.mainThreadBlock);
 #endif
   callRuntimeCallbacks(__ATINIT__);
 }

src/struct_info.json

@@ -1236,7 +1236,10 @@
 
             "EM_HTML5_SHORT_STRING_LEN_BYTES",
             "EM_HTML5_MEDIUM_STRING_LEN_BYTES",
-            "EM_HTML5_LONG_STRING_LEN_BYTES"
+            "EM_HTML5_LONG_STRING_LEN_BYTES",
+
+            "EM_CALLBACK_THREAD_CONTEXT_MAIN_BROWSER_THREAD",
+            "EM_CALLBACK_THREAD_CONTEXT_CALLING_THREAD"
         ],
         "structs": {
             "EmscriptenKeyboardEvent": [
@@ -1491,7 +1494,15 @@
             "EM_THREAD_STATUS_SLEEPING",
             "EM_THREAD_STATUS_WAITFUTEX",
             "EM_THREAD_STATUS_WAITPROXY",
-            "EM_THREAD_STATUS_FINISHED"
+            "EM_THREAD_STATUS_FINISHED",
+            "EM_FUNC_SIG_V",
+            "EM_FUNC_SIG_VI",
+            "EM_FUNC_SIG_VII",
+            "EM_FUNC_SIG_VIII",
+            "EM_FUNC_SIG_I",
+            "EM_FUNC_SIG_II",
+            "EM_FUNC_SIG_III",
+            "EM_FUNC_SIG_IIII"
             ]
     },
     {

system/include/emscripten/html5.h

@@ -8,6 +8,18 @@
 #ifndef __emscripten_events_h__
 #define __emscripten_events_h__
 
+#ifdef __cplusplus
+#if !defined(__DEFINED_pthread_t)
+typedef unsigned long pthread_t;
+#define __DEFINED_pthread_t
+#endif
+#else
+#if !defined(__DEFINED_pthread_t)
+typedef struct __pthread * pthread_t;
+#define __DEFINED_pthread_t
+#endif
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -452,6 +464,9 @@ extern EMSCRIPTEN_RESULT emscripten_get_canvas_element_size(const char *target,
 extern EMSCRIPTEN_RESULT emscripten_set_element_css_size(const char *target, double width, double height);
 extern EMSCRIPTEN_RESULT emscripten_get_element_css_size(const char *target, double *width, double *height);
 
+#define EM_CALLBACK_THREAD_CONTEXT_MAIN_BROWSER_THREAD ((pthread_t)0x1)
+#define EM_CALLBACK_THREAD_CONTEXT_CALLING_THREAD ((pthread_t)0x2)
+
 #ifdef __cplusplus
 } // ~extern "C"
 #endif