Remove DETERMINISTIC setting

I'm not sure there are any users of this settings, but in case there
are I have left the `src/deterministic.js` file in place which can be
used via `--pre-js` instead.

Fixes: #26647

Author: sbc100

ChangeLog.md

@@ -20,6 +20,10 @@ See docs/process.md for more on how version tagging works.
 
 5.0.6 (in development)
 ----------------------
+- The `-sDETERMINISTIC` setting was removed.  This setting just injected
+  `src/deterministic.js` as a `--pre-js`.  For now, this file remains part of
+  emscripten.  If you are a user of this feature please let us know otherwise
+  this may be deleted in a future release.
 - The minimum version of node supported by the generated code was bumped from
   v12.22.0 to v18.3.0. (#26604)
 

site/source/docs/tools_reference/settings_reference.rst

@@ -1775,20 +1775,6 @@ testing.  See test_chunked_synchronous_xhr in runner.py and library.js.
 
 Default value: false
 
-.. _deterministic:
-
-DETERMINISTIC
-=============
-
-If 1, we force Date.now(), Math.random, etc. to return deterministic results.
-This also tries to make execution deterministic across machines and
-environments, for example, not doing anything different based on the
-browser's language setting (which would mean you can get different results
-in different browsers, or in the browser and in node).
-Good for comparing builds for debugging purposes (and nothing else).
-
-Default value: false
-
 .. _modularize:
 
 MODULARIZE
@@ -3511,3 +3497,4 @@ for backwards compatibility with older versions:
  - ``NODEJS_CATCH_REJECTION``: No longer supported (Valid values: [0])
  - ``POLYFILL_OLD_MATH_FUNCTIONS``: No longer supported (Valid values: [0])
  - ``RELOCATABLE``: No longer supported (Valid values: [0])
+ - ``DETERMINISTIC``: No longer supported (Valid values: [0])

src/deterministic.js

@@ -20,7 +20,6 @@ Date.now = deterministicNow;
 // Note: this approach does not work on certain versions of Node.js
 // Specifically it seems like its not possible to override performance.now on
 // node v16 through v18.
-// See getPerformanceNow in parseTools.mjs for how we deal with this.
 if (globalThis.performance) performance.now = deterministicNow;
 
 // for consistency between different builds than between runs of the same build

src/lib/libcore.js

@@ -1355,25 +1355,25 @@ addToLibrary({
 
   emscripten_date_now: () => Date.now(),
 
-  emscripten_performance_now: () => {{{ getPerformanceNow() }}}(),
+  emscripten_performance_now: () => performance.now(),
 
 #if PTHREADS && !AUDIO_WORKLET
   // Pthreads need their clocks synchronized to the execution of the main
   // thread, so, when using them, make sure to adjust all timings to the
   // respective time origins.
-  emscripten_get_now: () => performance.timeOrigin + {{{ getPerformanceNow() }}}(),
+  emscripten_get_now: () => performance.timeOrigin + performance.now(),
 #else
 #if AUDIO_WORKLET // https://github.com/WebAudio/web-audio-api/issues/2413
   emscripten_get_now: `;
     // AudioWorkletGlobalScope does not have performance.now()
     // (https://github.com/WebAudio/web-audio-api/issues/2527), so if building
     // with
     // Audio Worklets enabled, do a dynamic check for its presence.
-    if (globalThis.performance && {{{ getPerformanceNow() }}}) {
+    if (globalThis.performance && performance.now) {
 #if PTHREADS
-      _emscripten_get_now = () => performance.timeOrigin + {{{ getPerformanceNow() }}}();
+      _emscripten_get_now = () => performance.timeOrigin + performance.now();
 #else
-      _emscripten_get_now = () => {{{ getPerformanceNow() }}}();
+      _emscripten_get_now = () => performance.now();
 #endif
     } else {
       _emscripten_get_now = Date.now;
@@ -1383,7 +1383,7 @@ addToLibrary({
   // Modern environment where performance.now() is supported:
   // N.B. a shorter form "_emscripten_get_now = performance.now;" is
   // unfortunately not allowed even in current browsers (e.g. FF Nightly 75).
-  emscripten_get_now: () => {{{ getPerformanceNow() }}}(),
+  emscripten_get_now: () => performance.now(),
 #endif
 #endif
 

src/lib/libwasi.js

@@ -50,13 +50,7 @@ var WasiLibrary = {
   $getEnvStrings: () => {
     if (!getEnvStrings.strings) {
       // Default values.
-#if DETERMINISTIC
-      // Deterministic language detection, ignore the browser's language.
-      var lang = 'C.UTF-8';
-#else
-      // Browser language detection #8751
       var lang = (globalThis.navigator?.language ?? 'C').replace('-', '_') + '.UTF-8';
-#endif
       var env = {
 #if !PURE_WASI
         'USER': 'web_user',

src/parseTools.mjs

@@ -1105,17 +1105,6 @@ function formattedMinNodeVersion() {
   return `v${major}.${minor}.${rev}`;
 }
 
-function getPerformanceNow() {
-  // This is needed to support Node.js v16 - v18 where `performance.now`
-  // cannot be overridden in the normal way.
-  // TODO(sbc): remove this once we drop support for these versions.
-  if (DETERMINISTIC && ENVIRONMENT_MAY_BE_NODE) {
-    return 'deterministicNow';
-  } else {
-    return 'performance.now';
-  }
-}
-
 function ENVIRONMENT_IS_MAIN_THREAD() {
   return `(!${ENVIRONMENT_IS_WORKER_THREAD()})`;
 }
@@ -1231,7 +1220,6 @@ addToCompileTimeContext({
   getHeapForType,
   getHeapOffset,
   getNativeTypeSize,
-  getPerformanceNow,
   getUnsharedTextDecoderView,
   hasExportedSymbol,
   isSymbolNeeded,

src/postamble.js

@@ -10,10 +10,6 @@
 #include "source_map_support.js"
 #endif
 
-#if DETERMINISTIC
-#include "deterministic.js"
-#endif
-
 #if ASSERTIONS
 var calledRun;
 #endif

src/settings.js

@@ -1206,15 +1206,6 @@ var ERROR_ON_UNDEFINED_SYMBOLS = true;
 // [link]
 var SMALL_XHR_CHUNKS = false;
 
-// If 1, we force Date.now(), Math.random, etc. to return deterministic results.
-// This also tries to make execution deterministic across machines and
-// environments, for example, not doing anything different based on the
-// browser's language setting (which would mean you can get different results
-// in different browsers, or in the browser and in node).
-// Good for comparing builds for debugging purposes (and nothing else).
-// [link]
-var DETERMINISTIC = false;
-
 // By default we emit all code in a straightforward way into the output
 // .js file. That means that if you load that in a script tag in a web
 // page, it will use the global scope. With ``MODULARIZE`` set, we instead emit

test/test_other.py

@@ -12059,7 +12059,7 @@ def test_deterministic(self):
   printf("JS random: %d\n", EM_ASM_INT({ return Math.random() }));
 }
 ''')
-    self.run_process([EMCC, 'src.c', '-sDETERMINISTIC'] + self.get_cflags())
+    self.run_process([EMCC, 'src.c', '--pre-js', path_from_root('src/deterministic.js')] + self.get_cflags())
     one = self.run_js('a.out.js')
     # ensure even if the time resolution is 1 second, that if we see the real
     # time we'll see a difference

tools/settings.py

@@ -252,6 +252,7 @@
     ['NODEJS_CATCH_REJECTION', [0], 'No longer supported'],
     ['POLYFILL_OLD_MATH_FUNCTIONS', [0], 'No longer supported'],
     ['RELOCATABLE', [0], 'No longer supported'],
+    ['DETERMINISTIC', [0], 'No longer supported'],
 ]
 
 user_settings: dict[str, str] = {}