#52791: build: don't build the crowdsourced V8 compile hints producer
Merged
Created: Aug 12, 2026, 12:48:12 PM
Merged: Aug 12, 2026, 2:39:08 PM
4 comments
Target: main
Description of Change
- Sets
produce_v8_compile_hints = falseso Blink builds the stubV8CrowdsourcedCompileHintsProducer(the configuration Android already ships) instead of the real one. - The real producer picks 0.5% of renderer processes on Windows (
v8_compile_hints_producer.cc) and, for the first page in that process, compiles every http(s) classic script from source: an existing V8 code cache is deliberately not consumed and local compile hints are neither consumed nor produced (v8_code_cache.cc), so it can record which functions were compiled to UKM. - The consuming half lives in
chrome/browser/v8_compile_hints/and requires OptimizationGuide, and Electron has no UKM backend, so the recorded data is never used; the only observable effect of the producer is a cold-cache load for 1 in 200 renderer processes on Windows. - Verified locally on Linux:
gnregeneratesbindings/buildflags.hwithPRODUCE_V8_COMPILE_HINTS=0,v8_compile_hints_producer.ocompiles down to the stub, and the build links and runs.
Checklist
- PR description included and stakeholders cc'd
- PR title follows semantic commit guidelines
- PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.
Release Notes
Notes: Fixed a 1-in-200 chance per renderer process on Windows of scripts on the first page load being compiled without their V8 code cache.
Backports
42-x-y
PendingWaiting for a manual backport
43-x-y
PendingWaiting for a manual backport
Semver Impact
Major
Breaking changes
Minor
New features
Patch
Bug fixes
None
Docs, tests, etc.
Semantic Versioning helps users understand the impact of updates:
- Major (X.y.z): Breaking changes that may require code modifications
- Minor (x.Y.z): New features that maintain backward compatibility
- Patch (x.y.Z): Bug fixes that don't change the API
- None: Changes that don't affect using facing parts of Electron