[libs][iOS] AdvSimdEncode hits PlatformNotSupportedException

[mdh1418]

Description

After #95513 was merged, some tests that eventually invoke EncodeToUtf8 such as

runtime/src/libraries/System.Collections/tests/Generic/PriorityQueue/PriorityQueue.PropertyTests.cs

Line 19 in 31fa079

public static void HeapSort_Heapify_String(string[] elements)

began failing with PlatformNotSupportedException on iOS/tvOS arm64 lanes.

Test collection for System.Collections.Tests.PriorityQueue_PropertyTests
Test name: System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String
Exception messages: System.PlatformNotSupportedException : 
Exception stack traces:    at System.Runtime.Intrinsics.Arm.AdvSimd.Arm64.LoadVector128x3AndUnzip(Byte* address)
at System.Buffers.Text.Base64.EncodeToUtf8(ReadOnlySpan`1 bytes, Span`1 utf8, Int32& bytesConsumed, Int32& bytesWritten, Boolean isFinalBlock)
at System.Convert.ToBase64CharsLargeNoLineBreaks(ReadOnlySpan`1 bytes, Span`1 chars, Int32 charLengthRequired)
at System.Convert.ToBase64String(ReadOnlySpan`1 bytes, Base64FormattingOptions options)
at System.Convert.ToBase64String(Byte[] inArray)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenString(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenArray[String](Func`2 genElement, Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<>c.<GetRandomStringArrays>b__16_0(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<GenerateMemberData>d__18`1[[System.String[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
at System.Linq.Enumerable.SelectEnumerableIterator`2[[System.Object, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Object[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()

It looks like LoadVector128x3AndUnzip is possibly the culprit, as #84510 doesn't seem to account for mono.

Reproduction Steps

On OSX with an iOS device

./build.sh -s mono+libs -os ios -arch arm64 -c debug
./dotnet.sh build src/libraries/System.Collections/tests/System.Collections.Tests.csproj /t:Test /p:TargetOS=ios /p:TargetArchitecture=arm64 /p:Configuration=Debug /p:DevTeamProvisioning=<dev team provisioning ID> /p:XunitMethodName=System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String /p:MonoEnableLLVM=true /p:RunAOTCompilation=true

Expected behavior

Test doesn't fail with PlatformNotSupportedException

Actual behavior

Various tests eventually that end up calling AdvSimd.Arm64.LoadVector128x3AndUnzip on iOS/tvOS fail with PlatformNotSupportedException

Regression?

Yes

Known Workarounds

No-op AdvSimdEncode on mono

Configuration

No response

Other information

No response

[mdh1418]

cc: @kunalspathak @SwapnilGaikwad @fanyang-mono @lambdageek

[kunalspathak]

@vargaz, @fanyang-mono - do you know what is needed on mono side? We did that previously for Store APIs in https://github.com/dotnet/runtime/pull/93223/files#diff-012b47a27abc5dbc9d2a0b6fdef4adec27fa207a7d2b53823a8bc80f6539f5af. Probably need similar changes for Load APIs?

[vargaz]

Would suggest adding an ifdef MONO around that code until this is fixed.

[fanyang-mono]

There is not software fallback codepath for AdvSimd.Arm64.LoadVector128x3AndUnzip. When it is not intrinsified by the runtime, it will throw System.PlatformNotSupportedException. Current solution would be avoid using AdvSimd.Arm64.LoadVector128x3AndUnzip and other new API's in #84510 for BCL methods when using Mono runtime, until they are implemented by Mono.

[ghost]

Tagging subscribers to this area: @dotnet/area-system-runtime-intrinsics
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

After #95513 was merged, some tests that eventually invoke EncodeToUtf8 such as

runtime/src/libraries/System.Collections/tests/Generic/PriorityQueue/PriorityQueue.PropertyTests.cs

Line 19 in 31fa079

public static void HeapSort_Heapify_String(string[] elements)

began failing with PlatformNotSupportedException on iOS/tvOS arm64 lanes.

Test collection for System.Collections.Tests.PriorityQueue_PropertyTests
Test name: System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String
Exception messages: System.PlatformNotSupportedException : 
Exception stack traces:    at System.Runtime.Intrinsics.Arm.AdvSimd.Arm64.LoadVector128x3AndUnzip(Byte* address)
at System.Buffers.Text.Base64.EncodeToUtf8(ReadOnlySpan`1 bytes, Span`1 utf8, Int32& bytesConsumed, Int32& bytesWritten, Boolean isFinalBlock)
at System.Convert.ToBase64CharsLargeNoLineBreaks(ReadOnlySpan`1 bytes, Span`1 chars, Int32 charLengthRequired)
at System.Convert.ToBase64String(ReadOnlySpan`1 bytes, Base64FormattingOptions options)
at System.Convert.ToBase64String(Byte[] inArray)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenString(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.GenArray[String](Func`2 genElement, Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<>c.<GetRandomStringArrays>b__16_0(Random random)
at System.Collections.Tests.PriorityQueue_PropertyTests.<GenerateMemberData>d__18`1[[System.String[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()
at System.Linq.Enumerable.SelectEnumerableIterator`2[[System.Object, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Object[], System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext()

It looks like LoadVector128x3AndUnzip is possibly the culprit, as #84510 doesn't seem to account for mono.

Reproduction Steps

On OSX with an iOS device

./build.sh -s mono+libs -os ios -arch arm64 -c debug
./dotnet.sh build src/libraries/System.Collections/tests/System.Collections.Tests.csproj /t:Test /p:TargetOS=ios /p:TargetArchitecture=arm64 /p:Configuration=Debug /p:DevTeamProvisioning=<dev team provisioning ID> /p:XunitMethodName=System.Collections.Tests.PriorityQueue_PropertyTests.HeapSort_Heapify_String /p:MonoEnableLLVM=true /p:RunAOTCompilation=true

Expected behavior

Test doesn't fail with PlatformNotSupportedException

Actual behavior

Various tests eventually that end up calling AdvSimd.Arm64.LoadVector128x3AndUnzip on iOS/tvOS fail with PlatformNotSupportedException

Regression?

Yes

Known Workarounds

No-op AdvSimdEncode on mono

Configuration

No response

Other information

No response

Author:	mdh1418
Assignees:	-
Labels:	arch-arm64, area-System.Runtime.Intrinsics
Milestone:	-

[kunalspathak]

Current solution would be avoid using AdvSimd.Arm64.LoadVector128x3AndUnzip and other new API's in #84510 for BCL methods when using Mono runtime, until they are implemented by Mono

Should we create an issue to implement these or is it already captured somewhere?

[fanyang-mono]

@kunalspathak I've created one to track that work. #93081

[jeffhandley]

With #93081 open, is there anything more to do on this issue or can it be closed?

[fanyang-mono]

@lambdageek will run this test locally to see if it is passing now. If so, we could close this issue. Since #93081 has been completed.

Thanks, @lambdageek

[tannergooding]

@lambdageek, were you able to complete the testing?

I did some basic testing locally and it looked to be working as expected

[tannergooding]

Going to close this as the local validation shows its no longer an issue and I don't see failures in recent CI runs.

Please reopen if the issue repros anywhere else.