Move most of Pthread.initRuntime into native code. NFC

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