[analyzer] Deduplicate _Info* instances

When having several contexts we'll end up having many copies of the same
_Info* instances. This CL deduplicates it.
TL;DR: On flutter/flutter (82 contexts) this, when run from a clean
cache, reduces the memory usage by 600-800 MB (~15%).

Details:

All numbers from runs made from analyzer source with a clean cache on
flutter/flutter (82 contexts), memory usage after a forced GC:

Runtime:
No difference proven at 95.0% confidence

Current memory (GB):
Difference at 95.0% confidence
        -0.683333 +/- 0.0627592
        -13.3987% +/- 1.23057%
        (Student's t, pooled s = 0.0276887)

Peak memory (GB):
Difference at 95.0% confidence
        -0.643333 +/- 0.0746028
        -12.5243% +/- 1.45236%
        (Student's t, pooled s = 0.032914)

Heap (used) (GB):
Difference at 95.0% confidence
        -0.77 +/- 0
        -17.5799% +/- 0%
        (Student's t, pooled s = 0)

Heap (capacity) (GB):
Difference at 95.0% confidence
        -0.69 +/- 0.05552
        -15.2993% +/- 1.23104%
        (Student's t, pooled s = 0.0244949)

_List (MB):
Difference at 95.0% confidence
        -59.2333 +/- 0.0925333
        -6.91547% +/- 0.0108032%
        (Student's t, pooled s = 0.0408248)

_Uint32List (MB):
Difference at 95.0% confidence
        -105.433 +/- 1.06715
        -17.3382% +/- 0.175489%
        (Student's t, pooled s = 0.470815)

_OneByteString (MB):
Difference at 95.0% confidence
        -403.667 +/- 2.37542
        -58.1206% +/- 0.342017%
        (Student's t, pooled s = 1.04801)

Raw data:

NOW:

Runtime (ms): 151855
current memory	4.46GB
peak memory	4.54GB
heap 3.61GB of 3.86GB
797.3 MB 6067774 _List
503.1 MB 2574937 _Uint32List
291.7 MB 2233396 _OneByteString
233.0 MB 338029 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901830 _Map

Runtime (ms): 152410
current memory	4.40GB
peak memory	4.49GB
heap 3.61GB of 3.80GB
797.3 MB 6067637 _List
503.0 MB 2574976 _Uint32List
290.7 MB 2232326 _OneByteString
226.8 MB 339447 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901830 _Map

Runtime (ms): 153205
current memory	4.39GB
peak memory	4.45GB
heap 3.61GB of 3.80GB
797.3 MB 6067638 _List
501.9 MB 2556644 _Uint32List
290.2 MB 2235718 _OneByteString
226.7 MB 338584 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901830 _Map




BEFORE:

Runtime (ms): 159178
current memory	5.09GB
peak memory	5.15GB
heap 4.38GB of 4.51GB
856.6 MB 7366027 _List
696.0 MB 3780593 _OneByteString
608.1 MB 5239817 _Uint32List
226.9 MB 341102 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901829 _Map

Runtime (ms): 153913
current memory	5.11GB
peak memory	5.13GB
heap 4.38GB of 4.51GB
856.5 MB 7366249 _List
693.8 MB 3730773 _OneByteString
608.1 MB 5239925 _Uint32List
233.0 MB 338205 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901829 _Map

Runtime (ms): 157729
current memory	5.10GB
peak memory	5.13GB
heap 4.38GB of 4.51GB
856.5 MB 7366221 _List
693.8 MB 3730773 _OneByteString
608.1 MB 5239924 _Uint32List
233.0 MB 337860 _Uint8List
158.7 MB 3466691 Reference
116.1 MB 1901829 _Map

Change-Id: I5697ff0efd40c9325f7f15d8092655b80b4876ac
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/318940
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
12 files changed
tree: a0e74625b0cc7aba88d495732e846cfc4d54ec69
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. sdk/
  10. tests/
  11. third_party/
  12. tools/
  13. utils/
  14. .clang-format
  15. .gitattributes
  16. .gitconfig
  17. .gitignore
  18. .gn
  19. .mailmap
  20. .style.yapf
  21. .vpython
  22. AUTHORS
  23. BUILD.gn
  24. CHANGELOG.md
  25. codereview.settings
  26. CONTRIBUTING.md
  27. DEPS
  28. LICENSE
  29. OWNERS
  30. PATENT_GRANT
  31. PRESUBMIT.py
  32. README.dart-sdk
  33. README.md
  34. sdk.code-workspace
  35. sdk_args.gni
  36. SECURITY.md
  37. WATCHLISTS
README.md

Dart

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