[SE-0163] Migrate from deprecated Unicode APIs (part 3) #33175

benrimmington · 2020-07-29T01:14:00Z

Follow-up to: #32920

benrimmington · 2020-07-29T01:15:59Z

stdlib/public/core/StaticString.swift

-      var buffer: UInt64 = 0
-      var i = 0
-      let sink: (UInt8) -> Void = {
-#if _endian(little)
-        buffer = buffer | (UInt64($0) << (UInt64(i) * 8))
-#else
-        buffer = buffer | (UInt64($0) << (UInt64(7-i) * 8))
-#endif
-        i += 1
-      }
-      UTF8.encode(unicodeScalar, into: sink)
-      return body(UnsafeBufferPointer(
-        start: UnsafePointer(Builtin.addressof(&buffer)),
-        count: i))
+      return unicodeScalar.withUTF8CodeUnits { body($0) }


This is using the internal Unicode.Scalar.withUTF8CodeUnits(_:) method, which has been ABI-public since Swift 5.0 — I assume it will also be available in the bundled stdlib (e.g. when targeting macOS 10.9).

Yep, those were built from the same sources!

(It's unfortunate that this non-public entry point is missing its leading underscore.)

(There was also a fix in Swift 5.1 for big-endian platforms.)

benrimmington · 2020-07-29T01:16:42Z

test/IRGen/objc_super.swift

-// CHECK: @"$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFyAEcfU_"
+// CHECK: @"$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFxAFXEfU_"


This test now has a different closure #1 type in its mangled name.

Old swift-demangle result:

$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFyAEcfU_ ---> closure #1 (Swift.UInt8) -> () in Swift.StaticString.withUTF8Buffer<A>((Swift.UnsafeBufferPointer<Swift.UInt8>) -> A) -> A

New swift-demangle result:

$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFxAFXEfU_ ---> closure #1 (Swift.UnsafeBufferPointer<Swift.UInt8>) -> A in Swift.StaticString.withUTF8Buffer<A>((Swift.UnsafeBufferPointer<Swift.UInt8>) -> A) -> A

benrimmington · 2020-07-29T01:19:31Z

@swift-ci Please smoke test

lorentey

This looks good to me! 👍 (Cc @milseman, too)

lorentey · 2020-07-29T04:15:56Z

stdlib/public/core/StaticString.swift

-      var buffer: UInt64 = 0
-      var i = 0
-      let sink: (UInt8) -> Void = {
-#if _endian(little)
-        buffer = buffer | (UInt64($0) << (UInt64(i) * 8))
-#else
-        buffer = buffer | (UInt64($0) << (UInt64(7-i) * 8))
-#endif
-        i += 1
-      }
-      UTF8.encode(unicodeScalar, into: sink)
-      return body(UnsafeBufferPointer(
-        start: UnsafePointer(Builtin.addressof(&buffer)),
-        count: i))
+      return unicodeScalar.withUTF8CodeUnits { body($0) }


Yep, those were built from the same sources!

(It's unfortunate that this non-public entry point is missing its leading underscore.)

lorentey · 2020-07-29T04:18:29Z

@swift-ci benchmark

swift-ci · 2020-07-29T05:19:39Z

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
Set.isSuperset.Seq.Empty.Int	47	55	+17.0%	0.85x (?)
Set.isDisjoint.Seq.Int.Empty	45	52	+15.6%	0.87x (?)
Set.isSubset.Seq.Empty.Int	76	84	+10.5%	0.90x (?)
ObjectiveCBridgeStringHash	81	88	+8.6%	0.92x (?)
Set.subtracting.Empty.Int	26	28	+7.7%	0.93x (?)

Improvement	OLD	NEW	DELTA	RATIO
Breadcrumbs.MutatedUTF16ToIdx.Mixed	314	273	-13.1%	1.15x (?)
Breadcrumbs.MutatedIdxToUTF16.Mixed	321	280	-12.8%	1.15x

Code size: -O

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
Set.isSuperset.Seq.Empty.Int	46	52	+13.0%	0.88x (?)
UTF8Decode_InitFromData	146	165	+13.0%	0.88x (?)
StringComparison_ascii	373	408	+9.4%	0.91x (?)
UTF8Decode_InitFromBytes	160	174	+8.7%	0.92x (?)

Improvement	OLD	NEW	DELTA	RATIO
Breadcrumbs.MutatedUTF16ToIdx.Mixed	316	274	-13.3%	1.15x (?)
Breadcrumbs.MutatedIdxToUTF16.Mixed	321	279	-13.1%	1.15x (?)
FlattenListFlatMap	2768	2439	-11.9%	1.13x (?)
Array2D	4832	4384	-9.3%	1.10x
ObjectiveCBridgeStubToNSDateRef	2380	2220	-6.7%	1.07x (?)
DropFirstCountableRange	15	14	-6.7%	1.07x (?)

Code size: -Osize

Performance: -Onone

Regression	OLD	NEW	DELTA	RATIO
StringFromLongWholeSubstring	9	10	+11.1%	0.90x (?)

Improvement	OLD	NEW	DELTA	RATIO
Breadcrumbs.MutatedUTF16ToIdx.Mixed	330	288	-12.7%	1.15x (?)
Breadcrumbs.MutatedIdxToUTF16.Mixed	337	295	-12.5%	1.14x (?)
ArrayAppendLatin1Substring	31608	29232	-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 mini
  Model Identifier: Macmini8,1
  Processor Name: 6-Core Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB

milseman · 2020-08-06T17:58:09Z

LGTM

[SE-0163] Migrate from deprecated Unicode APIs (part 3)

c4ea828

benrimmington commented Jul 29, 2020

View reviewed changes

benrimmington requested review from lorentey and milseman July 29, 2020 03:51

lorentey approved these changes Jul 29, 2020

View reviewed changes

milseman approved these changes Aug 6, 2020

View reviewed changes

benrimmington merged commit d3f0de8 into swiftlang:master Aug 6, 2020

benrimmington deleted the se-0163-migration-3 branch August 6, 2020 22:45

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[SE-0163] Migrate from deprecated Unicode APIs (part 3) #33175

[SE-0163] Migrate from deprecated Unicode APIs (part 3) #33175

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benrimmington commented Jul 29, 2020

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milseman commented Aug 6, 2020

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		// CHECK: @"$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFyAEcfU_"
		// CHECK: @"$ss12StaticStringV14withUTF8BufferyxxSRys5UInt8VGXElFxAFXEfU_"

[SE-0163] Migrate from deprecated Unicode APIs (part 3) #33175

[SE-0163] Migrate from deprecated Unicode APIs (part 3) #33175

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swift-ci commented Jul 29, 2020

Performance: -O

Code size: -O

Performance: -Osize

Code size: -Osize

Performance: -Onone

Code size: -swiftlibs

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milseman commented Aug 6, 2020

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