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Calculate transitive JS library deps after symbolHandler in --symbols-only mode. NFC - #28052
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…ols-only` mode. NFC Previously, `getTransitiveDeps` was called inside `addFromLibrary` while `symbolHandler` was still iterating through `symbolsNeeded` and mutating `__deps` (such as adding `setTempRet0` for i64-returning functions without `WASM_BIGINT`). Compute `symbolDeps` in the `if (symbolsOnly)` block after `symbolHandler` completes so that all direct `__deps` are populated before traversing the dependency graph. Split out from emscripten-core#27995.
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This pull request refactors the --symbols-only mode in src/jsifier.mjs by moving the dependency resolution logic for library symbols to the end of the runJSify function, where it iterates over all keys of LibraryManager.library. However, calling the unmemoized getTransitiveDeps function on every library symbol introduces a performance bottleneck due to quadratic traversal of the dependency graph. It is recommended to implement a memoized version of dependency resolution to optimize compilation performance.
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Cache the computed transitive dependency list for each symbol in `transitiveDepsCache` and reuse cached results when traversing dependencies in subsequent `getTransitiveDeps` calls. Only completed top-level traversals are inserted into the cache so that cyclic dependencies (such as `$FS` <-> `$MEMFS`) are handled safely without caching partial results. In `tools/compiler.mjs --symbols-only`, this reduces graph node visits in `getTransitiveDeps` by ~9x (from 39,349 to 4,381), cutting the `symbolDeps` calculation time by ~41% (from ~16.0ms to ~9.5ms) and overall `--symbols-only` execution time by ~4.6% (from ~152ms to ~145ms). See: emscripten-core#28052
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sbc100
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Cache the computed transitive dependency list for each symbol in `transitiveDepsCache` and reuse cached results when traversing dependencies in subsequent `getTransitiveDeps` calls. Only completed top-level traversals are inserted into the cache so that cyclic dependencies (such as `$FS` <-> `$MEMFS`) are handled safely without caching partial results. In `tools/compiler.mjs --symbols-only`, this reduces graph node visits in `getTransitiveDeps` by ~9x (from 39,349 to 4,381), cutting the `symbolDeps` calculation time by ~41% (from ~16.0ms to ~9.5ms) and overall `--symbols-only` execution time by ~4.6% (from ~152ms to ~145ms). See: emscripten-core#28052
kripken
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Previously,
getTransitiveDepswas called insideaddFromLibrarywhilesymbolHandlerwas still iterating throughsymbolsNeededand mutating__deps(such as addingsetTempRet0for i64-returning functions withoutWASM_BIGINT).Compute
symbolDepsin theif (symbolsOnly)block aftersymbolHandlercompletes so that all direct__depsare populated before traversing the dependency graph.Split out from #27995.