Honor DEFAULT_PTHREAD_STACK_SIZE in pthread_attr_init (#19333)

Also remove the extra `_emscripten_default_pthread_stack_size`
import/call in favor of just passing this information in during
`_emscripten_thread_init`.

Fixes: #19302, #15101

Author: sbc100

emscripten.py

@@ -893,7 +893,7 @@ def create_wasm64_wrappers(metadata):
     '_emscripten_run_in_main_runtime_thread_js': '___p_',
     '_emscripten_proxy_execute_task_queue': '_p',
     '_emscripten_thread_exit': '_p',
-    '_emscripten_thread_init': '_p____',
+    '_emscripten_thread_init': '_p_____',
     '_emscripten_thread_free_data': '_p',
     '_emscripten_dlsync_self_async': '_p',
     '_emscripten_proxy_dlsync_async': '_pp',

src/library_pthread.js

@@ -722,6 +722,7 @@ var LibraryPThread = {
       /*isMainBrowserThread=*/!ENVIRONMENT_IS_WORKER,
       /*isMainRuntimeThread=*/1,
       /*canBlock=*/!ENVIRONMENT_IS_WEB,
+      {{{ DEFAULT_PTHREAD_STACK_SIZE }}},
 #if PTHREADS_PROFILING
       /*start_profiling=*/true
 #endif
@@ -1042,12 +1043,6 @@ var LibraryPThread = {
     return func.apply(null, emscripten_receive_on_main_thread_js_callArgs);
   },
 
-  // TODO(sbc): Do we really need this to be dynamically settable from JS like this?
-  // See https://github.com/emscripten-core/emscripten/issues/15101.
-  _emscripten_default_pthread_stack_size: function() {
-    return {{{ DEFAULT_PTHREAD_STACK_SIZE }}};
-  },
-
 #if STACK_OVERFLOW_CHECK >= 2 && MAIN_MODULE
   $establishStackSpace__deps: ['$setDylinkStackLimits'],
 #endif

src/library_sigs.js

@@ -300,7 +300,6 @@ sigs = {
   _embind_register_void__sig: 'vpp',
   _emscripten_create_wasm_worker__sig: 'ipi',
   _emscripten_dbg__sig: 'vp',
-  _emscripten_default_pthread_stack_size__sig: 'i',
   _emscripten_dlopen_js__sig: 'vpppp',
   _emscripten_dlsync_threads__sig: 'v',
   _emscripten_dlsync_threads_async__sig: 'vppp',

system/lib/pthread/emscripten_thread_init.c

@@ -7,13 +7,18 @@
 #include <pthread.h>
 #include "emscripten/threading.h"
 #include "threading_internal.h"
+#include "pthread_impl.h"
 
 void _emscripten_thread_init(pthread_t ptr,
                              int is_main,
                              int is_runtime,
                              int can_block,
+                             int default_stacksize,
                              int start_profiling) {
   __set_thread_state(ptr, is_main, is_runtime, can_block);
+  if (is_main && default_stacksize) {
+    __default_stacksize = default_stacksize;
+  }
 #ifndef NDEBUG
   if (start_profiling) {
     _emscripten_thread_profiler_enable();

system/lib/pthread/library_pthread_stub.c

@@ -279,10 +279,6 @@ int pthread_condattr_setpshared(pthread_condattr_t *attr, int shared) {
   return 0;
 }
 
-int pthread_attr_init(pthread_attr_t *attr) {
-  return 0;
-}
-
 int pthread_getattr_np(pthread_t thread, pthread_attr_t *attr) {
   return 0;
 }
@@ -389,6 +385,10 @@ void __lock(void* ptr) {}
 
 void __unlock(void* ptr) {}
 
+void __acquire_ptc() {}
+
+void __release_ptc() {}
+
 // 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.
 void emscripten_thread_sleep(double msecs) {

system/lib/pthread/pthread_create.c

@@ -140,7 +140,7 @@ int __pthread_create(pthread_t* restrict res,
   pthread_attr_t attr = { 0 };
   if (attrp && attrp != __ATTRP_C11_THREAD) attr = *attrp;
   if (!attr._a_stacksize) {
-    attr._a_stacksize = _emscripten_default_pthread_stack_size();
+    attr._a_stacksize = __default_stacksize;
   }
 
   // Allocate memory for new thread.  The layout of the thread block is
@@ -149,7 +149,7 @@ int __pthread_create(pthread_t* restrict res,
   // 1. pthread struct (sizeof struct pthread)
   // 2. tls data       (__builtin_wasm_tls_size())
   // 3. tsd pointers   (__pthread_tsd_size)
-  // 4. stack          (_emscripten_default_pthread_stack_size())
+  // 4. stack          (__default_stacksize AKA -sDEFAULT_PTHREAD_STACK_SIZE)
   size_t size = sizeof(struct pthread);
   if (__builtin_wasm_tls_size()) {
     size += __builtin_wasm_tls_size() + __builtin_wasm_tls_align() - 1;

test/other/metadce/test_metadce_minimal_pthreads.exports

@@ -4,7 +4,7 @@ C
 D
 E
 F
-G
+p
 q
 r
 s

test/other/metadce/test_metadce_minimal_pthreads.imports

@@ -13,4 +13,3 @@ a.l
 a.m
 a.n
 a.o
-a.p

test/other/metadce/test_metadce_minimal_pthreads.jssize

@@ -1 +1 @@
-15448
+15425

test/other/metadce/test_metadce_minimal_pthreads.sent

@@ -13,4 +13,3 @@ l
 m
 n
 o
-p