Remove POLYFILL_OLD_MATH_FUNCTIONS setting

These polyfills are only needed on ancient browser versions that we
no longer support.

Our minimum supported browser versions are currently chrome 45, firefox
40, safari 10.1 and node 10.19.

Author: sbc100

ChangeLog.md

@@ -48,6 +48,9 @@ See docs/process.md for more on how version tagging works.
   `--post-js` files will now be delayed until after module creation and after
   `main` runs.  This matches the existing behaviour when using sync instantation
   (`-sWASM_ASYNC_COMPILATION=0`) but is an observable difference. (#23157)
+- The `POLYFILL_OLD_MATH_FUNCTIONS` setting was removed.  The browser versions
+  that require these polyfills are no longer supported by emscripten so the
+  polyfills should never be needed.
 
 3.1.74 - 12/14/24
 -----------------

site/source/docs/tools_reference/settings_reference.rst

@@ -959,25 +959,14 @@ can also vary between browsers.
 
 Default value: false
 
-.. _polyfill_old_math_functions:
-
-POLYFILL_OLD_MATH_FUNCTIONS
-===========================
-
-If set, enables polyfilling for Math.clz32, Math.trunc, Math.imul, Math.fround.
-
-Default value: false
-
 .. _legacy_vm_support:
 
 LEGACY_VM_SUPPORT
 =================
 
-Set this to enable compatibility emulations for old JavaScript engines. This gives you
 the highest possible probability of the code working everywhere, even in rare old
 browsers and shell environments. Specifically:
 
-- Add polyfilling for Math.clz32, Math.trunc, Math.imul, Math.fround. (-sPOLYFILL_OLD_MATH_FUNCTIONS)
 - Disable WebAssembly. (Must be paired with -sWASM=0)
 - Adjusts MIN_X_VERSION settings to 0 to include support for all browser versions.
 - Avoid TypedArray.fill, if necessary, in zeroMemory utility function.

src/preamble.js

@@ -324,8 +324,6 @@ function addOnPostRun(cb) {
   __ATPOSTRUN__.unshift(cb);
 }
 
-#include "runtime_math.js"
-
 // A counter of dependencies for calling run(). If we need to
 // do asynchronous work before running, increment this and
 // decrement it. Incrementing must happen in a place like

src/preamble_minimal.js

@@ -85,7 +85,6 @@ var runtimeExited = false;
 var runtimeInitialized = false;
 #endif
 
-#include "runtime_math.js"
 #include "memoryprofiler.js"
 #include "runtime_exceptions.js"
 #include "runtime_debug.js"

src/runtime_math.js

@@ -619,15 +619,9 @@ var GL_ENABLE_GET_PROC_ADDRESS = true;
 // [link]
 var JS_MATH = false;
 
-// If set, enables polyfilling for Math.clz32, Math.trunc, Math.imul, Math.fround.
-// [link]
-var POLYFILL_OLD_MATH_FUNCTIONS = false;
-
-// Set this to enable compatibility emulations for old JavaScript engines. This gives you
 // the highest possible probability of the code working everywhere, even in rare old
 // browsers and shell environments. Specifically:
 //
-// - Add polyfilling for Math.clz32, Math.trunc, Math.imul, Math.fround. (-sPOLYFILL_OLD_MATH_FUNCTIONS)
 // - Disable WebAssembly. (Must be paired with -sWASM=0)
 // - Adjusts MIN_X_VERSION settings to 0 to include support for all browser versions.
 // - Avoid TypedArray.fill, if necessary, in zeroMemory utility function.
@@ -2267,4 +2261,5 @@ var LEGACY_SETTINGS = [
   ['MIN_IE_VERSION', [0x7FFFFFFF], 'No longer supported'],
   ['WORKAROUND_OLD_WEBGL_UNIFORM_UPLOAD_IGNORED_OFFSET_BUG', [0], 'No longer supported'],
   ['AUTO_ARCHIVE_INDEXES', [0, 1], 'No longer needed'],
+  ['POLYFILL_OLD_MATH_FUNCTIONS', [0], 'No longer supported'],
 ];

src/settings.js

@@ -1157,9 +1157,6 @@ def phase_linker_setup(options, state, newargs):  # noqa: C901, PLR0912, PLR0915
     if settings.MINIMAL_RUNTIME and options.oformat == OFormat.HTML and not settings.PTHREADS:
       settings.USE_READY_PROMISE = 0
 
-  if settings.WASM2JS and settings.LEGACY_VM_SUPPORT:
-    settings.POLYFILL_OLD_MATH_FUNCTIONS = 1
-
   check_browser_versions()
 
   if settings.MIN_NODE_VERSION >= 150000:
@@ -1202,10 +1199,6 @@ def phase_linker_setup(options, state, newargs):  # noqa: C901, PLR0912, PLR0915
     diagnostics.warning('transpile', '-sEXCEPTION_STACK_TRACES requires an engine that support ES6 classes.')
     settings.EXCEPTION_STACK_TRACES = 0
 
-  # Silently drop any individual backwards compatibility emulation flags that are known never to occur on browsers that support WebAssembly.
-  if not settings.WASM2JS:
-    settings.POLYFILL_OLD_MATH_FUNCTIONS = 0
-
   if settings.STB_IMAGE:
     state.append_link_flag('-lstb_image')
     settings.EXPORTED_FUNCTIONS += ['_stbi_load', '_stbi_load_from_memory', '_stbi_image_free']