Move most of Pthread.initRuntime into native code. NFC (#14775)

This also avoids the use of malloc both for the main pthread struct and
for its TLS vars.  This in turn avoids the use of `withBuiltinMalloc`
since we no longer use malloc here.

Author: sbc100

emcc.py

@@ -1863,7 +1863,6 @@ def default_setting(name, new_default):
       '_emscripten_get_global_libc',
       '_emscripten_main_browser_thread_id',
       '_emscripten_main_thread_process_queued_calls',
-      '_emscripten_register_main_browser_thread_id',
       '_emscripten_run_in_main_runtime_thread_js',
       '_emscripten_stack_set_limits',
       '_emscripten_sync_run_in_main_thread_2',

src/library_pthread.js

@@ -7,12 +7,8 @@
 var LibraryPThread = {
   $PThread__postset: 'if (!ENVIRONMENT_IS_PTHREAD) PThread.initMainThreadBlock();',
   $PThread__deps: ['_emscripten_thread_init',
-                   'emscripten_register_main_browser_thread_id',
                    'emscripten_futex_wake', '$killThread',
                    '$cancelThread', '$cleanupThread',
-#if USE_ASAN || USE_LSAN
-                   , '$withBuiltinMalloc'
-#endif
                    ],
   $PThread: {
     // Contains all Workers that are idle/unused and not currently hosting an
@@ -37,33 +33,7 @@ var LibraryPThread = {
       }
 #endif
     },
-    initRuntime: function() {
-#if USE_ASAN || USE_LSAN
-      // When sanitizers are enabled, malloc is normally instrumented to call
-      // sanitizer code that checks some things about pthreads. As we are just
-      // setting up the main thread here, and are not ready for such calls,
-      // call malloc directly.
-      withBuiltinMalloc(function () {
-#endif
-
-      var tb = _malloc({{{ C_STRUCTS.pthread.__size__ }}});
-
-      for (var i = 0; i < {{{ C_STRUCTS.pthread.__size__ }}}/4; ++i) HEAPU32[tb/4+i] = 0;
-
-      // The pthread struct has a field that points to itself - this is used as
-        // a magic ID to detect whether the pthread_t structure is 'alive'.
-      {{{ makeSetValue('tb', C_STRUCTS.pthread.self, 'tb', 'i32') }}};
-
-      // pthread struct robust_list head should point to itself.
-      var headPtr = tb + {{{ C_STRUCTS.pthread.robust_list }}};
-      {{{ makeSetValue('headPtr', 0, 'headPtr', 'i32') }}};
-
-      // Allocate memory for thread-local storage.
-      var tlsMemory = _malloc({{{ cDefine('PTHREAD_KEYS_MAX') * 4 }}});
-      for (var i = 0; i < {{{ cDefine('PTHREAD_KEYS_MAX') }}}; ++i) HEAPU32[tlsMemory/4+i] = 0;
-      Atomics.store(HEAPU32, (tb + {{{ C_STRUCTS.pthread.tsd }}} ) >> 2, tlsMemory); // Init thread-local-storage memory array.
-      Atomics.store(HEAPU32, (tb + {{{ C_STRUCTS.pthread.tid }}} ) >> 2, tb); // Main thread ID.
-
+    initRuntime: function(tb) {
 #if PTHREADS_PROFILING
       PThread.createProfilerBlock(tb);
       PThread.setThreadName(tb, "Browser main thread");
@@ -74,14 +44,9 @@ var LibraryPThread = {
       // globals which act as a form of TLS. Global constructors trying
       // to access this value will read the wrong value, but that is UB anyway.
       __emscripten_thread_init(tb, /*isMainBrowserThread=*/!ENVIRONMENT_IS_WORKER, /*isMainRuntimeThread=*/1);
-      _emscripten_register_main_browser_thread_id(tb);
 #if ASSERTIONS
       PThread.mainRuntimeThread = true;
 #endif
-
-#if USE_ASAN || USE_LSAN
-      });
-#endif
     },
     initWorker: function() {
 #if USE_CLOSURE_COMPILER
@@ -568,6 +533,7 @@ var LibraryPThread = {
     pthread.worker.postMessage({ 'cmd': 'cancel' });
   },
 
+  $spawnThread__deps: ['$zeroMemory'],
   $spawnThread: function(threadParams) {
     if (ENVIRONMENT_IS_PTHREAD) throw 'Internal Error! spawnThread() can only ever be called from main application thread!';
 
@@ -582,10 +548,8 @@ var LibraryPThread = {
     PThread.runningWorkers.push(worker);
 
     // Allocate memory for thread-local storage and initialize it to zero.
-    var tlsMemory = _malloc({{{ cDefine('PTHREAD_KEYS_MAX') }}} * 4);
-    for (var i = 0; i < {{{ cDefine('PTHREAD_KEYS_MAX') }}}; ++i) {
-      {{{ makeSetValue('tlsMemory', 'i*4', 0, 'i32') }}};
-    }
+    var tlsMemory = _malloc({{{ cDefine('PTHREAD_KEYS_MAX') * 4 }}});
+    zeroMemory(tlsMemory, {{{ cDefine('PTHREAD_KEYS_MAX') * 4 }}});
 
     var stackHigh = threadParams.stackBase + threadParams.stackSize;
 
@@ -822,7 +786,7 @@ var LibraryPThread = {
     // Allocate thread block (pthread_t structure).
     var threadInfoStruct = _malloc({{{ C_STRUCTS.pthread.__size__ }}});
     // zero-initialize thread structure.
-    for (var i = 0; i < {{{ C_STRUCTS.pthread.__size__ }}} >> 2; ++i) HEAPU32[(threadInfoStruct>>2) + i] = 0;
+    zeroMemory(threadInfoStruct, {{{ C_STRUCTS.pthread.__size__ }}});
     {{{ makeSetValue('pthread_ptr', 0, 'threadInfoStruct', 'i32') }}};
 
     // The pthread struct has a field that points to itself - this is used as a

system/lib/libc/musl/src/thread/pthread_getspecific.c

@@ -4,6 +4,10 @@
 static void *__pthread_getspecific(pthread_key_t k)
 {
 	struct pthread *self = __pthread_self();
+	// XXX EMSCRIPTEN: self->tsd can be NULL in the case of the
+	// main thread where pthread_key_create is not called.
+	// See __pthread_key_create for where it get assigned.
+	if (!self->tsd) return NULL;
 	return self->tsd[k];
 }
 

system/lib/pthread/library_pthread.c

@@ -405,15 +405,10 @@ EMSCRIPTEN_RESULT emscripten_wait_for_call_i(
   return res;
 }
 
-static pthread_t main_browser_thread_id_ = 0;
-
-void emscripten_register_main_browser_thread_id(
-  pthread_t main_browser_thread_id) {
-  main_browser_thread_id_ = main_browser_thread_id;
-}
+static struct pthread __main_pthread;
 
 pthread_t emscripten_main_browser_thread_id() {
-  return main_browser_thread_id_;
+  return &__main_pthread;
 }
 
 int _emscripten_do_dispatch_to_thread(pthread_t target_thread, em_queued_call* call) {
@@ -886,8 +881,8 @@ int _emscripten_call_on_thread(int forceAsync, pthread_t targetThread, EM_FUNC_S
 // the main thread is waiting, we wake it up before waking up any workers.
 EMSCRIPTEN_KEEPALIVE void* _emscripten_main_thread_futex;
 
-EM_JS(void, initPthreadsJS, (void), {
-  PThread.initRuntime();
+EM_JS(void, initPthreadsJS, (void* tb), {
+  PThread.initRuntime(tb);
 })
 
 // We must initialize the runtime at the proper time, which is after memory is
@@ -898,6 +893,15 @@ EM_JS(void, initPthreadsJS, (void), {
 EMSCRIPTEN_KEEPALIVE
 __attribute__((constructor(48)))
 void __emscripten_pthread_data_constructor(void) {
-  initPthreadsJS();
-  pthread_self()->locale = &libc.global_locale;
+  initPthreadsJS(&__main_pthread);
+  // The pthread struct has a field that points to itself - this is used as
+  // a magic ID to detect whether the pthread_t structure is 'alive'.
+  __main_pthread.self = &__main_pthread;
+      // pthread struct robust_list head should point to itself.
+  __main_pthread.robust_list.head = &__main_pthread.robust_list;
+
+  // Main thread ID.
+  __main_pthread.tid = (long)&__main_pthread;
+
+  __main_pthread.locale = &libc.global_locale;
 }

tests/other/metadce/minimal_main_Oz_USE_PTHREADS_PROXY_TO_PTHREAD.exports

@@ -14,7 +14,6 @@ M
 N
 O
 P
-Q
 t
 u
 v

tests/other/metadce/minimal_main_Oz_USE_PTHREADS_PROXY_TO_PTHREAD.funcs

@@ -31,7 +31,6 @@ $emscripten_current_thread_process_queued_calls
 $emscripten_get_global_libc
 $emscripten_main_thread_process_queued_calls
 $emscripten_proxy_main
-$emscripten_register_main_browser_thread_id
 $emscripten_run_in_main_runtime_thread_js
 $emscripten_stack_set_limits
 $emscripten_sync_run_in_main_thread

tests/other/metadce/minimal_main_Oz_USE_PTHREADS_PROXY_TO_PTHREAD.size

@@ -1 +1 @@
-16031
+16084