Update Emscripten SDK from 3.1.28 to 4.0.23#1907
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Summary: Yoga's JavaScript bindings previously used Emscripten embind to bridge C++ wrapper classes to JavaScript. This added unnecessary overhead and complexity: JS calls went through embind → C++ wrapper classes (Node.cpp, Config.cpp) → Yoga C API, requiring the embind runtime to be bundled into the WASM output. This diff removes embind entirely. JavaScript now calls Yoga's C API directly, with a thin C bridge (wasm_bridge.c, ~140 lines) handling only what raw C exports cannot: - Struct returns (YGValue) via a static buffer read through HEAPF32/HEAP32 - Measure/dirtied callbacks via EM_JS dispatching to JS-side Maps The JS side (wrapAssembly.ts) is rewritten to use classes (NodeImpl, ConfigImpl) that store a WASM pointer and call C functions directly via `lib._YGFunctionName()`. Tree hierarchy (children/parent) is tracked entirely in JS, matching the pattern used by the Java JNI bindings. To avoid maintaining a hardcoded EXPORTED_FUNCTIONS list, YG_EXPORT is extended on Emscripten to include `__attribute__((used))` (matching EMSCRIPTEN_KEEPALIVE). Combined with `-fvisibility=hidden` and `--export-dynamic`, this ensures all public Yoga C API functions are automatically exported from WASM — no manual list needed. The closure compiler is retained for JS glue minification. The public API shape (Yoga, Node, Config types) remains identical. **Bundle size (SINGLE_FILE base64-embedded WASM):** | Metric | Before (embind) | After (direct C) | Change | |---|---|---|---| | Raw | 126,288 B | 115,370 B | -8.6% | | Gzip | 51,042 B | 42,764 B | -16.2% | **Benchmark results (median of 3 runs):** | Benchmark | Before | After | Change | |---|---|---|---| | Stack with flex | 20ms | 8ms | 2.5x faster | | Align stretch in undefined axis | 19ms | 5ms | 3.8x faster | | Nested flex | 17ms | 4ms | 4.3x faster | | Huge nested layout | 18ms | 5ms | 3.6x faster | Fixes react#1545 Differential Revision: D95011356
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Summary: Update the Emscripten SDK used for the JavaScript WASM build from 3.1.28 to 4.0.23. This brings ~2 years of Emscripten improvements including better WASM codegen and smaller JS glue output. Required build config changes for Emscripten 4.x compatibility: - Remove `--memory-init-file 0` (deprecated, no longer accepted) - Change `TEXTDECODER=0` to `TEXTDECODER=2` (0 is no longer valid) - Add `EXPORTED_RUNTIME_METHODS=['HEAPF32','HEAP32']` (heap views are no longer on Module by default in 4.x) **Bundle size:** | Metric | emsdk 3.1.28 | emsdk 4.0.23 | Change | |---|---|---|---| | Raw | 115,370 B | 90,219 B | -21.8% | | Gzip | 42,764 B | 34,445 B | -19.4% | **Benchmark results (median of 3 runs):** | Benchmark | 3.1.28 | 4.0.23 | Change | |---|---|---|---| | Stack with flex | 9ms | 6ms | similar | | Align stretch | 5ms | 4ms | similar | | Nested flex | 4ms | 4ms | same | | Huge nested layout | 5ms | 4ms | similar | Reviewed By: cortinico Differential Revision: D95012856
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Summary: Update the Emscripten SDK used for the JavaScript WASM build from 3.1.28 to 4.0.23. This brings ~2 years of Emscripten improvements including better WASM codegen and smaller JS glue output. Required build config changes for Emscripten 4.x compatibility: - Remove `--memory-init-file 0` (deprecated, no longer accepted) - Change `TEXTDECODER=0` to `TEXTDECODER=2` (0 is no longer valid) - Add `EXPORTED_RUNTIME_METHODS=['HEAPF32','HEAP32']` (heap views are no longer on Module by default in 4.x) **Bundle size:** | Metric | emsdk 3.1.28 | emsdk 4.0.23 | Change | |---|---|---|---| | Raw | 115,370 B | 90,219 B | -21.8% | | Gzip | 42,764 B | 34,445 B | -19.4% | **Benchmark results (median of 3 runs):** | Benchmark | 3.1.28 | 4.0.23 | Change | |---|---|---|---| | Stack with flex | 9ms | 6ms | similar | | Align stretch | 5ms | 4ms | similar | | Nested flex | 4ms | 4ms | same | | Huge nested layout | 5ms | 4ms | similar | Reviewed By: cortinico Differential Revision: D95012856
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Summary: Pull Request resolved: react#1907 Update the Emscripten SDK used for the JavaScript WASM build from 3.1.28 to 4.0.23. This brings ~2 years of Emscripten improvements including better WASM codegen and smaller JS glue output. Required build config changes for Emscripten 4.x compatibility: - Remove `--memory-init-file 0` (deprecated, no longer accepted) - Change `TEXTDECODER=0` to `TEXTDECODER=2` (0 is no longer valid) - Add `EXPORTED_RUNTIME_METHODS=['HEAPF32','HEAP32']` (heap views are no longer on Module by default in 4.x) **Bundle size:** | Metric | emsdk 3.1.28 | emsdk 4.0.23 | Change | |---|---|---|---| | Raw | 115,370 B | 90,219 B | -21.8% | | Gzip | 42,764 B | 34,445 B | -19.4% | **Benchmark results (median of 3 runs):** | Benchmark | 3.1.28 | 4.0.23 | Change | |---|---|---|---| | Stack with flex | 9ms | 6ms | similar | | Align stretch | 5ms | 4ms | similar | | Nested flex | 4ms | 4ms | same | | Huge nested layout | 5ms | 4ms | similar | Reviewed By: cortinico Differential Revision: D95012856
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Summary:
Update the Emscripten SDK used for the JavaScript WASM build from
3.1.28 to 4.0.23. This brings ~2 years of Emscripten improvements
including better WASM codegen and smaller JS glue output.
Required build config changes for Emscripten 4.x compatibility:
--memory-init-file 0(deprecated, no longer accepted)TEXTDECODER=0toTEXTDECODER=2(0 is no longer valid)EXPORTED_RUNTIME_METHODS=['HEAPF32','HEAP32'](heap views areno longer on Module by default in 4.x)
Bundle size:
Benchmark results (median of 3 runs):
Differential Revision: D95012856