Move __syscall__newselect to native code. NFC (#25985)

After #25523 this function is no longer proxied itself and therefore
doesn't need to live in JS at all.

Author: sbc100

src/lib/libsigs.js

@@ -229,7 +229,6 @@ sigs = {
   __handle_stack_overflow__sig: 'vp',
   __pthread_create_js__sig: 'ipppp',
   __resumeException__sig: 'vp',
-  __syscall__newselect__sig: 'iipppj',
   __syscall_accept4__sig: 'iippiii',
   __syscall_bind__sig: 'iippiii',
   __syscall_chdir__sig: 'ip',

src/lib/libsyscall.js

@@ -599,31 +599,6 @@ var SyscallsLibrary = {
     FS.chdir(stream.path);
     return 0;
   },
-  __syscall__newselect__i53abi: true,
-  __syscall__newselect__proxy: 'none',
-  __syscall__newselect__deps: ['_newselect_js',
-#if PTHREADS
-    '_emscripten_proxy_newselect',
-#endif
-  ],
-  __syscall__newselect: (nfds, readfds, writefds, exceptfds, timeoutInMillis) => {
-#if PTHREADS
-    if (ENVIRONMENT_IS_PTHREAD) {
-      return __emscripten_proxy_newselect(nfds,
-                                          {{{ to64('readfds') }}},
-                                          {{{ to64('writefds') }}},
-                                          {{{ to64('exceptfds') }}},
-                                          {{{ splitI64('timeoutInMillis') }}});
-    }
-#endif
-      return __newselect_js({{{ to64('0') }}},
-                            {{{ to64('0') }}},
-                            nfds,
-                            {{{ to64('readfds') }}},
-                            {{{ to64('writefds') }}},
-                            {{{ to64('exceptfds') }}},
-                            {{{ splitI64('timeoutInMillis') }}});
-  },
   _newselect_js__i53abi: true,
   _newselect_js__proxy: 'none',
   _newselect_js__deps: ['$parseSelectFDSet',

system/lib/libc/proxying_select.c

@@ -6,16 +6,18 @@
  */
 
 #include <assert.h>
+#include <sys/select.h>
 #include <emscripten/proxying.h>
 #include <emscripten/threading.h>
 
 #include "emscripten_internal.h"
 
+#if _REENTRANT
 typedef struct proxied_select_t {
   int n;
-  void *rfds;
-  void *wfds;
-  void *efds;
+  fd_set *rfds;
+  fd_set *wfds;
+  fd_set *efds;
   int64_t timeout;
   int result;
 } proxied_select_t;
@@ -31,7 +33,7 @@ void _emscripten_proxy_newselect_finish(em_proxying_ctx* ctx, void* arg, int ret
   emscripten_proxy_finish(ctx);
 }
 
-int _emscripten_proxy_newselect(int n, void *rfds, void *wfds, void *efds, int64_t timeout) {
+static int proxy_newselect(int n, fd_set *rfds, fd_set *wfds, fd_set *efds, int64_t timeout) {
   em_proxying_queue* q = emscripten_proxy_get_system_queue();
   pthread_t target = emscripten_main_runtime_thread_id();
   proxied_select_t t = {.n = n, .rfds = rfds, .wfds = wfds, .efds = efds, .timeout = timeout};
@@ -41,3 +43,17 @@ int _emscripten_proxy_newselect(int n, void *rfds, void *wfds, void *efds, int64
   }
   return t.result;
 }
+#endif
+
+// Marked as weak since libwasmfs needs to be able to override this.
+weak int __syscall__newselect(int nfds, intptr_t _readfds, intptr_t _writefds, intptr_t _exceptfds, int64_t timeout) {
+  fd_set* readfds = (fd_set*)_readfds;
+  fd_set* writefds = (fd_set*)_writefds;
+  fd_set* exceptfds = (fd_set*)_exceptfds;
+#if _REENTRANT
+  if (!emscripten_is_main_runtime_thread()) {
+    return proxy_newselect(nfds, readfds, writefds, exceptfds, timeout);
+  }
+#endif
+  return _newselect_js(0, 0, nfds, readfds, writefds, exceptfds, timeout);
+}

system/lib/wasmfs/syscalls.cpp

@@ -1848,8 +1848,4 @@ int __syscall__newselect(int nfds,
   return count;
 }
 
-int _newselect_js(void* ctx, void* arg, int n, void *rfds, void *wfds, void *efds, int64_t timeout) {
-  return -ENOSYS;
-}
-
 } // extern "C"

test/codesize/test_codesize_hello_dylink_all.json

@@ -1,7 +1,7 @@
 {
-  "a.out.js": 245771,
-  "a.out.nodebug.wasm": 573904,
-  "total": 819675,
+  "a.out.js": 245592,
+  "a.out.nodebug.wasm": 573702,
+  "total": 819294,
   "sent": [
     "IMG_Init",
     "IMG_Load",
@@ -215,7 +215,6 @@
     "__asctime_r",
     "__assert_fail",
     "__call_sighandler",
-    "__syscall__newselect",
     "__syscall_accept4",
     "__syscall_bind",
     "__syscall_chdir",
@@ -1406,7 +1405,6 @@
     "GOT.func.emscripten_out",
     "env.__assert_fail",
     "env.__call_sighandler",
-    "env.__syscall__newselect",
     "env.__syscall_accept4",
     "env.__syscall_bind",
     "env.__syscall_chdir",
@@ -1865,6 +1863,7 @@
     "__subvsi3",
     "__subvti3",
     "__synccall",
+    "__syscall__newselect",
     "__syscall_acct",
     "__syscall_getegid32",
     "__syscall_geteuid32",
@@ -1963,8 +1962,6 @@
     "_emscripten_find_dylib",
     "_emscripten_memcpy_bulkmem",
     "_emscripten_memset_bulkmem",
-    "_emscripten_proxy_newselect",
-    "_emscripten_proxy_newselect_finish",
     "_emscripten_run_callback_on_thread",
     "_emscripten_set_offscreencanvas_size_on_thread",
     "_emscripten_stack_alloc",
@@ -3740,6 +3737,7 @@
     "$__subvsi3",
     "$__subvti3",
     "$__synccall",
+    "$__syscall__newselect",
     "$__syscall_acct",
     "$__syscall_getgroups32",
     "$__syscall_getpid",
@@ -3826,8 +3824,6 @@
     "$_emscripten_find_dylib",
     "$_emscripten_memcpy_bulkmem",
     "$_emscripten_memset_bulkmem",
-    "$_emscripten_proxy_newselect",
-    "$_emscripten_proxy_newselect_finish",
     "$_emscripten_run_callback_on_thread",
     "$_emscripten_set_offscreencanvas_size_on_thread",
     "$_emscripten_stack_alloc",
@@ -3911,7 +3907,6 @@
     "$cacoshl",
     "$cacosl",
     "$call",
-    "$call_newselect",
     "$call_once",
     "$carg",
     "$cargf",

tools/emscripten.py

@@ -1202,7 +1202,6 @@ def create_pointer_conversion_wrappers(metadata):
     '_emscripten_dlsync_self_async': '_p',
     '_emscripten_proxy_dlsync_async': '_pp',
     '_emscripten_wasm_worker_initialize': '_p_',
-    '_emscripten_proxy_newselect': '__ppp_',
     '_emscripten_proxy_newselect_finish': '_pp_',
     '_wasmfs_rename': '_pp',
     '_wasmfs_readlink': '_pp',