[guybedford]

This extends the module compile cache (module.enableCompileCache() / NODE_COMPILE_CACHE) to WebAssembly modules loaded through the ES module integration.

• A new kWasm cache entry type, keyed on the module URL with the wire bytes as the hashed source, stores V8's CompiledWasmModule serialization.
• On load, cached code is deserialized through v8::WasmModuleCompilation with the same compile options the wasm translator uses (js-string builtins and imported string constants), falling back to new WebAssembly.Module() when V8 rejects it.
• CompileCacheHandler::GetOrInsert gains a raw-bytes overload used by the new entry type; the string overload delegates to it.

The WasmModuleObject::CompileOptions API this relies on is included in the V8 15.5 update now on main, so no V8 patch is needed.

As for JavaScript, the entry is captured right after compilation. V8 only serializes optimized-tier code, so with the default lazy baseline compilation there is nothing to cache and no entry is written. A complete cache requires --no-liftoff --no-wasm-lazy-compilation, which compiles everything with the optimizing tier at module creation; since V8 flags are part of the cache key, all processes sharing the cache must use the same flags. This is documented in a new section of module.md.

The test covers both the eager-compilation case (entry written, then deserialized and accepted on the second run) and the default case (nothing serialized, no entry written).

[nodejs-github-bot]

Review requested:

• @nodejs/gyp
• @nodejs/loaders
• @nodejs/security-wg
• @nodejs/v8-update

[codecov]

Codecov Report

❌ Patch coverage is 85.54913% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.65%. Comparing base (ddba9a5) to head (f291da1).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_modules.cc	80.16%	5 Missing and 19 partials ⚠️
src/compile_cache.cc	96.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66191      +/-   ##
==========================================
- Coverage   90.65%   90.65%   -0.01%     
==========================================
  Files         797      797              
  Lines      278268   278429     +161     
  Branches    53511    53536      +25     
==========================================
+ Hits       252258   252396     +138     
- Misses      16384    16394      +10     
- Partials     9626     9639      +13     

Files with missing lines	Coverage Δ
lib/internal/modules/esm/translators.js	97.63% <100.00%> (+0.06%)	⬆️
src/compile_cache.h	100.00% <ø> (ø)
src/compile_cache.cc	80.95% <96.00%> (+0.89%)	⬆️
src/node_modules.cc	79.75% <80.16%> (+0.27%)	⬆️

... and 25 files with indirect coverage changes

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[mcollina]

lgtm

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/77819/

[github-actions]

This pull request has conflicts with its base branch, removing the author ready label.
Please rebase your branch onto the latest base branch, resolve the conflicts locally, and force-push.
Afterwards the pull request needs a fresh collaborator approval, and a collaborator will add the label back once it is author ready again.

[GeoffreyBooth]

This is very cool.

[guybedford]

This is now rebased and no longer depends on the V8 patch. Will aim to land soon!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/78678/