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Use paged indexes for type-node and signature caches - #64803
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🟢 Approval recommended
The focused cache migration preserves behavior and has comprehensive targeted coverage.
0 open findings
What changed in this PR
Migrates checker type-node and signature caches to paged node-ID storage, reducing memory overhead.
Changes:
- Replaces pointer-keyed caches with
nodeLinkStore. - Adds coverage for fallback IDs, checker isolation, GC, and cloned nodes.
| File | Description |
|---|---|
tsc/internal/checker/checker.go |
Migrates two checker caches to paged storage. |
tsc/internal/checker/types_test.go |
Verifies cache correctness and isolation. |
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Resolved type nodes and signatures still kept AST pointers as map keys
despite already having stable node identities. Those maps add redundant
pointer storage, GC scanning, hashing, and growth allocations.
Reuse the existing node-link store's pointer-free paged indexes for
these two high-volume caches. Ordinary IDs and IDs outside the dense
reserved range retain the existing fallback, and caches stay
checker-local.
Six fresh-process interleaved VS Code comparisons against the parent
commit, using normal GC, reduce retained heap 1.20%, scan bytes 2.12%,
allocated bytes 2.11%, and allocation events 0.20%. Instructions are
inconclusive. This saves another roughly 43 MiB of heap and 66 MiB of
scanning.
Production diagnostics and semantic counts match exactly. Tests cover
cache identity, ordinary/reserved IDs, clone isolation, growth,
GC reachability, and independent checkers.
goos: linux
goarch: amd64
pkg: github.com/microsoft/TypeScript/tsc/internal/checker
cpu: Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz
│ vscode-paged-before-6.txt │ vscode-paged-6.txt │
│ retained-B │ retained-B vs base │
ExternalProgram-20 3.497Gi ± 0% 3.455Gi ± 0% -1.20% (p=0.002 n=6)
│ vscode-paged-before-6.txt │ vscode-paged-6.txt │
│ scan-B │ scan-B vs base │
ExternalProgram-20 3.061Gi ± 0% 2.997Gi ± 0% -2.12% (p=0.002 n=6)
│ vscode-paged-before-6.txt │ vscode-paged-6.txt │
│ B/op │ B/op vs base │
ExternalProgram-20 5.129Gi ± 0% 5.021Gi ± 0% -2.11% (p=0.002 n=6)
│ vscode-paged-before-6.txt │ vscode-paged-6.txt │
│ allocs/op │ allocs/op vs base │
ExternalProgram-20 31.16M ± 0% 31.09M ± 0% -0.20% (p=0.002 n=6)
│ paged-before-instructions.txt │ paged-instructions.txt │
│ instructions/op │ instructions/op vs base │
ExternalInstructions-20 279.8G ± 5% 270.5G ± 2% ~ (p=0.589 n=6)
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Resolved type nodes and signatures were cached in maps keyed by AST pointer, despite nodes already having stable IDs.
Part of the memory optimization stack summarized in #64734.
Replaces #64787, which GitHub closed as merged when the stack was reordered.