SIL optimizer: fix a compile time performance problem in UpdatingInstructionIteratorRegistry

[eeckstein]

C++ closures can implicitly malloc.
Avoid this by just capturing this and nothing else.

Reduces the time spent in the SIL pass pipeline by 25% when compiling the stdlib core.

rdar://88567996

[eeckstein]

@swift-ci smoke test

[eeckstein]

@swift-ci benchmark

[swift-ci]

Performance (x86_64): -O

Improvement	OLD	NEW	DELTA	RATIO
ArrayAppendGenericStructs	2090	1330	-36.4%	1.57x (?)
FlattenListLoop	2552	1673	-34.4%	1.53x (?)
StringBuilderWithLongSubstring	1630	1470	-9.8%	1.11x (?)
FlattenListFlatMap	6763	6101	-9.8%	1.11x (?)

Code size: -O

Performance (x86_64): -Osize

Improvement	OLD	NEW	DELTA	RATIO
FlattenListFlatMap	6669	3975	-40.4%	1.68x (?)
FlattenListLoop	2644	1770	-33.1%	1.49x (?)
Set.subtracting.Seq.Empty.Box	268	222	-17.2%	1.21x (?)
DictionaryKeysContainsCocoa	25	23	-8.0%	1.09x (?)

Code size: -Osize

Performance (x86_64): -Onone

Regression	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeFromNSSetAnyObjectForced	5540	6120	+10.5%	0.91x (?)
Improvement	OLD	NEW	DELTA	RATIO
RandomDoubleDef	55700	51200	-8.1%	1.09x (?)
RandomDoubleOpaqueDef	56200	52000	-7.5%	1.08x (?)

Code size: -swiftlibs

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the
regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false
alarms. Unexpected regressions which are marked with '(?)' are probably noise.
If you see regressions which you cannot explain you can try to run the
benchmarks again. If regressions still show up, please consult with the
performance team (@eeckstein).

Hardware Overview

  Model Name: Mac Pro
  Model Identifier: MacPro6,1
  Processor Name: 12-Core Intel Xeon E5
  Processor Speed: 2.7 GHz
  Number of Processors: 1
  Total Number of Cores: 12
  L2 Cache (per Core): 256 KB
  L3 Cache: 30 MB
  Memory: 64 GB

[atrick]

Thank you! Great compile time fix.