gh-160873: Remove obsolete pthread_getattr_np workaround (#160902)

Removes a workaround that was needed for older versions of Emscripten, 
but is no longer required. Also adapts to new command line arguments for
enabling threading.

Author: lpyu001

Platforms/emscripten/README.md

@@ -138,7 +138,7 @@ await createEmscriptenModule({
 
 - Threading is disabled by default. The ``configure`` option
   ``--enable-wasm-pthreads`` adds compiler flag ``-pthread`` and
-  linker flags ``-sUSE_PTHREADS -sPROXY_TO_PTHREAD``.
+  linker flags ``-pthread -sPROXY_TO_PTHREAD``.
 - pthread support requires WASM threads and SharedArrayBuffer (bulk memory).
   The Node.JS runtime keeps a pool of web workers around. Each web worker
   uses several file descriptors (eventfd, epoll, pipe).

Python/ceval.c

@@ -70,70 +70,6 @@ _Py_ReachedRecursionLimitWithMargin(PyThreadState *tstate, int margin_count)
 #  define Py_C_STACK_SIZE 4000000
 #endif
 
-#if defined(__EMSCRIPTEN__)
-
-// Temporary workaround to make `pthread_getattr_np` work on Emscripten.
-// Emscripten 4.0.6 will contain a fix:
-// https://github.com/emscripten-core/emscripten/pull/23887
-
-#include "emscripten/stack.h"
-
-#define pthread_attr_t workaround_pthread_attr_t
-#define pthread_attr_init workaround_pthread_attr_init
-#define pthread_getattr_np workaround_pthread_getattr_np
-#define pthread_attr_getguardsize workaround_pthread_attr_getguardsize
-#define pthread_attr_getstack workaround_pthread_attr_getstack
-#define pthread_attr_destroy workaround_pthread_attr_destroy
-
-typedef struct {
-    void *_a_stackaddr;
-    size_t _a_stacksize, _a_guardsize;
-} pthread_attr_t;
-
-extern __attribute__((__visibility__("hidden"))) unsigned __default_guardsize;
-
-int pthread_attr_init(pthread_attr_t *a)
-{
-	return 0;
-}
-
-// Modified version of pthread_getattr_np from the upstream PR.
-
-int pthread_getattr_np(pthread_t thread, pthread_attr_t *attr) {
-  attr->_a_stackaddr = (void*)emscripten_stack_get_base();
-  attr->_a_stacksize = emscripten_stack_get_base() - emscripten_stack_get_end();
-  attr->_a_guardsize = __default_guardsize;
-  return 0;
-}
-
-// These three functions copied without any changes from Emscripten libc.
-
-int pthread_attr_getguardsize(const pthread_attr_t *restrict a, size_t *restrict size)
-{
-	*size = a->_a_guardsize;
-	return 0;
-}
-
-int pthread_attr_getstack(const pthread_attr_t *restrict a, void **restrict addr, size_t *restrict size)
-{
-/// XXX musl is not standard-conforming? It should not report EINVAL if _a_stackaddr is zero, and it should
-///     report EINVAL if a is null: http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_attr_getstack.html
-	if (!a) return EINVAL;
-//	if (!a->_a_stackaddr)
-//		return EINVAL;
-
-	*size = a->_a_stacksize;
-	*addr = (void *)(a->_a_stackaddr - *size);
-	return 0;
-}
-
-int pthread_attr_destroy(pthread_attr_t *a)
-{
-	return 0;
-}
-
-#endif
-
 static void
 hardware_stack_limits(uintptr_t *base, uintptr_t *top, uintptr_t sp)
 {

configure

@@ -1153,12 +1153,12 @@ if test -z "$CFLAGS"; then
 fi
 
 dnl Emscripten SDK and WASI SDK default to wasm32.
-dnl On Emscripten use MEMORY64 setting to build target wasm64-emscripten.
+dnl On Emscripten use -m64 to build target wasm64-emscripten.
 dnl for wasm64.
 AS_CASE([$host],
   [wasm64-*-emscripten], [
-    AS_VAR_APPEND([CFLAGS], [" -sMEMORY64=1"])
-    AS_VAR_APPEND([LDFLAGS], [" -sMEMORY64=1"])
+    AS_VAR_APPEND([CFLAGS], [" -m64"])
+    AS_VAR_APPEND([LDFLAGS], [" -m64"])
   ],
 )
 
@@ -2659,7 +2659,7 @@ AS_CASE([$ac_sys_system],
 
     AS_VAR_IF([enable_wasm_pthreads], [yes], [
       AS_VAR_APPEND([CFLAGS_NODIST], [" -pthread"])
-      AS_VAR_APPEND([LDFLAGS_NODIST], [" -sUSE_PTHREADS"])
+      AS_VAR_APPEND([LDFLAGS_NODIST], [" -pthread"])
       AS_VAR_APPEND([LINKFORSHARED], [" -sPROXY_TO_PTHREAD"])
     ])
     dnl not completely sure whether or not we want -sEXIT_RUNTIME, keeping it for now.