Micro-optimize randomFill. NFC

Only use the node fallback code when its actually needed, otherwise assume that `crypto.getRandomValues` is available out-of-the-box (which it is on node v19 and above.
emscripten-core · Jan 6, 2025 · 61bcbd4 · 61bcbd4
1 parent 1b8b227
commit 61bcbd4
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Showing 23 changed files with 31 additions and 39 deletions.
diff --git a/src/library_wasi.js b/src/library_wasi.js
@@ -561,28 +561,20 @@ var WasiLibrary = {
   // random.h
 
   $initRandomFill: () => {
-    if (typeof crypto == 'object' && typeof crypto.getRandomValues == 'function') {
-#if SHARED_MEMORY
-      // like with most Web APIs, we can't use Web Crypto API directly on shared memory,
-      // so we need to create an intermediate buffer and copy it to the destination
-      return (view) => view.set(crypto.getRandomValues(new Uint8Array(view.byteLength)));
-#else
-      return (view) => crypto.getRandomValues(view);
-#endif
-    }
-
-#if ENVIRONMENT_MAY_BE_NODE
+#if ENVIRONMENT_MAY_BE_NODE && MIN_NODE_VERSION < 190000
     if (ENVIRONMENT_IS_NODE) {
-      return (view) => require('crypto').randomFillSync(view);
+      // Node v19 and above has globalThis.getRandomValues builtin
+      var nodeCrypto = require('crypto');
+      return (view) => nodeCrypto.randomFillSync(view);
     }
 #endif // ENVIRONMENT_MAY_BE_NODE
 
-    // we couldn't find a proper implementation, as Math.random() is not
-    // suitable for /dev/random, see emscripten-core/emscripten/pull/7096
-#if ASSERTIONS
-    abort('no cryptographic support found for random function. consider polyfilling it if you want to use something insecure like Math.random(), e.g. put this in a --pre-js: var crypto = { getRandomValues: (array) => { for (var i = 0; i < array.length; i++) array[i] = (Math.random()*256)|0 } };');
+#if SHARED_MEMORY
+    // like with most Web APIs, we can't use Web Crypto API directly on shared memory,
+    // so we need to create an intermediate buffer and copy it to the destination
+    return (view) => view.set(crypto.getRandomValues(new Uint8Array(view.byteLength)));
 #else
-    abort();
+    return (view) => crypto.getRandomValues(view);
 #endif
   },
 

diff --git a/test/other/codesize/test_codesize_cxx_ctors1.gzsize b/test/other/codesize/test_codesize_cxx_ctors1.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_ctors1.jssize b/test/other/codesize/test_codesize_cxx_ctors1.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_ctors2.gzsize b/test/other/codesize/test_codesize_cxx_ctors2.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_ctors2.jssize b/test/other/codesize/test_codesize_cxx_ctors2.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_except.gzsize b/test/other/codesize/test_codesize_cxx_except.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_except.jssize b/test/other/codesize/test_codesize_cxx_except.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.jssize b/test/other/codesize/test_codesize_cxx_except_wasm.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize b/test/other/codesize/test_codesize_cxx_except_wasm_exnref.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_lto.gzsize b/test/other/codesize/test_codesize_cxx_lto.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_lto.jssize b/test/other/codesize/test_codesize_cxx_lto.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_mangle.gzsize b/test/other/codesize/test_codesize_cxx_mangle.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_mangle.jssize b/test/other/codesize/test_codesize_cxx_mangle.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_noexcept.gzsize b/test/other/codesize/test_codesize_cxx_noexcept.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_noexcept.jssize b/test/other/codesize/test_codesize_cxx_noexcept.jssize
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diff --git a/test/other/codesize/test_codesize_cxx_wasmfs.gzsize b/test/other/codesize/test_codesize_cxx_wasmfs.gzsize
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diff --git a/test/other/codesize/test_codesize_cxx_wasmfs.jssize b/test/other/codesize/test_codesize_cxx_wasmfs.jssize
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diff --git a/test/other/codesize/test_codesize_files_js_fs.gzsize b/test/other/codesize/test_codesize_files_js_fs.gzsize
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diff --git a/test/other/codesize/test_codesize_files_js_fs.jssize b/test/other/codesize/test_codesize_files_js_fs.jssize
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diff --git a/test/other/codesize/test_codesize_files_wasmfs.gzsize b/test/other/codesize/test_codesize_files_wasmfs.gzsize
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diff --git a/test/other/codesize/test_codesize_files_wasmfs.jssize b/test/other/codesize/test_codesize_files_wasmfs.jssize
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