Auto merge of #158059 - xmakro:perf/lexer-ascii-symbolgallery, r=cjgillot

Skip query machinery when promoting disk-cached values



At the end of an incremental session, exec_cache_promotions walks the green nodes and, for queries that were never used this session, loads their value from the previous session's disk cache into memory so it gets written into the new cache. This load currently goes through the full query execution path and shows up in profiles of incremental builds with few or no changes, which is the motivation for this PR.

Instead, this PR only loads the value directly and puts it in the in-memory cache. Perf improvement: -1.3% mean instructions, mostly in incr-unchanged, -0.36% in incr-patched, no regressions, see https://github.com/rust-lang/rust/pull/158059#issuecomment-4827621427.

Behavior change: A missing disk value is now a bug instead of a silent recompute.
tree: 939ee67619bbf36b667822e16acfe73e9c7269b3
  1. .github/
  2. compiler/
  3. library/
  4. LICENSES/
  5. src/
  6. tests/
  7. .clang-format
  8. .editorconfig
  9. .git-blame-ignore-revs
  10. .gitattributes
  11. .gitignore
  12. .gitmodules
  13. .ignore
  14. .mailmap
  15. bootstrap.example.toml
  16. Cargo.lock
  17. Cargo.toml
  18. CODE_OF_CONDUCT.md
  19. configure
  20. CONTRIBUTING.md
  21. COPYRIGHT
  22. INSTALL.md
  23. LICENSE-APACHE
  24. license-metadata.json
  25. LICENSE-MIT
  26. package.json
  27. README.md
  28. RELEASES.md
  29. REUSE.toml
  30. rust-bors.toml
  31. rustfmt.toml
  32. triagebot.toml
  33. typos.toml
  34. x
  35. x.ps1
  36. x.py
  37. yarn.lock
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