…m64+ios/macos. (#96079)

* [mono] Fix passing of valuetypes with a non-8 byte aligned size on arm64+ios/macos.

Part of the fix for #96051.

* Reenable tests on non-interpreter.

* Fix.

…n explicit layout if the explicit size matches the computed size. (#96230)

This happens for Vector64<T>/Vector128<T>.

* Revamp empty special-casing in LINQ

Enumerable.Empty used to return Array.Empty. Towards the beginning of .NET Core, LINQ was imbued with an internal "partition" concept for flowing more information around between operators, and as part of that, Empty was changed to return a singleton instance of a specialized partition implementation. The upside of this was that methods typed to return IPartition could return the same singleton as Empty. There are multiple downsides, however. For one, the whole IPartition concept is only built into a "speed-optimized" build of LINQ; builds that care more about size (e.g. browser) end up not having it, and thus Empty there ends up being Array.Empty, such that a different type ends up being returned based on the build, which is not ideal. Further, any paths that check for empty now effectively have two things to check for: the empty partition or an empty array, making those checks more expensive, if they're even done at all, or in some cases missing out on possible optimization. This is more pronounced today, now that `[]` with collection expressions will produce Array.Empty, and it'd be really nice if there wasn't a difference between Enumerable.Empty and `[]` assigned to `IEnumerable<T>`.

This change puts Enumerable.Empty back to always being Array.Empty. The internal IPartition-based APIs that drove us to need the EmptyPartition are changed to just use null as an indication of empty. Places we were already checking for `is EmptyPartition` are changed to check for an empty array (if they weren't already), and other APIs that weren't checking at all now have a check if it makes sense to do so (I audited all of the APIs, and didn't include checks in ones where it could meaningfully affect semantics, e.g. a fast path that might cause us not to get an enumerator from a secondary enumerable input).

* Rename IsImmutableEmpty to IsEmptyArray per PR feedback

* Remove bogus PLINQ tests

The tests were validating the underlying type of the operator returned for Concat, which is not material.

* Fix Skip special-casing

The check needs to be moved to before the count <= 0 check... otherwise calling Skip on an empty array with a count of 0 would still allocate an iterator.

The implementations are special-casing most of the built-in ones, in order to delegate to the IBinaryInteger-constrained helper, but it was missing Int128, UInt128, and char. ?hese won't be vectorized, but they'll at least use the more streamlined non-vectorized implementations.

…5292)

* Add IndentText json option

* Add IndentText for json source generator

* Add tests

* IndentText must be non-nullable

* Improve performance

* Add extra tests

* Cleanup

* Apply suggestions from code review

Co-authored-by: Eirik Tsarpalis <[email protected]>

* Fixes following code review

* Fixes following code review #2

* Add tests for invalid characters

* Handle RawIndent length

* Move all to RawIndentation

* Update documentation

* Additional fixes from code review

* Move to the new API

* Extra fixes and enhancements

* Fixes from code review

* Avoid introducing extra fields in JsonWriterOptions

* Fix OOM error

* Use bitwise logic for IndentedOrNotSkipValidation

* Cache indentation options in Utf8JsonWriter

* Add missing test around indentation options

* New fixes from code review

* Update src/libraries/System.Text.Json/src/System/Text/Json/Writer/Utf8JsonWriter.cs

* Add test to check default values of the JsonWriterOptions properties

* Fix comment

---------

Co-authored-by: Eirik Tsarpalis <[email protected]>

* [mono][jit] Avoid creating rgctx trampolines to call gshared methods which don't use their mrgctx arg.

* Implement MONO_ARCH_HAVE_INIT_MRGCTX for x64.

* Implement a cross-platform optimized version of OP_INIT_MRGCTX.

… generic type (#96517)

* Fix generic signature issue when calling non generic method of closed generic type

* Apply feedbacks

…otnet-optimization build 20240106.4 (#96619)

optimization.linux-arm64.MIBC.Runtime , optimization.linux-x64.MIBC.Runtime , optimization.windows_nt-arm64.MIBC.Runtime , optimization.windows_nt-x64.MIBC.Runtime , optimization.windows_nt-x86.MIBC.Runtime , optimization.PGO.CoreCLR
 From Version 1.0.0-prerelease.23629.4 -> To Version 1.0.0-prerelease.24056.4

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

#96515)

* Fix uint greatetThan

* Enable disabled tests

* Add a new test

It was moved from src/mono/wasm to src/mono/browser in #95940

#96570)

There's a lot of code involved in these, some of which we special-case to only build into some of the targets, and it's unnecessarily complicated.  We can get most of the benefit with a simpler solution, which this attempts to provide. This commit removes those three types and replaces them with a SegmentedArrayBuilder.

The changes to ToArray also obviate the need for the old Buffer type. It existed to avoid one array allocation at the end of loading an enumerable, where we'd doubled and doubled and doubled in size, and then eventually have an array with all the data but some extra space. Now that we don't have such an array, we don't need Buffer, and can just the normal Enumerable.ToArray.

The one thing the new scheme doesn't handle as well is when there are multiple sources being added (specifically in Concat / SelectMany). Previously, the code used a complicated scheme to reserve space in the output for partial sources known to be ICollections, so it could use ICollection.CopyTo for each consistuent source. But CopyTo doesn't support partial copies, which means we can only use it if there's enough room available in an individual segment. The implementation thus tries to use it, and falls back to normal enumeration if it can't. For larger enumerations where the cost would end up being more apparent, the expectation is we'd quickly grow to a segment size where the subsequent appends are able to fit into the current segment. Hopefully.

* add SerialStream support for MacCatalyst

* feedback from review

* Explicitly set SupportedOSPlatforms for maccatalyst

It'd default to the unsupported annotation from iOS otherwise.

---------

Co-authored-by: Alexander Köplinger <[email protected]>

The code doesn't use a checked configuration, and if it did there are other expected overflows that would erroneously fail.

* Add .NET 8 test project for System.Numerics.Tensors

* Update src/libraries/System.Numerics.Tensors/tests/Net8Tests/System.Numerics.Tensors.Net8.Tests.csproj

Co-authored-by: Viktor Hofer <[email protected]>

---------

Co-authored-by: Viktor Hofer <[email protected]>

…mbly (#96462)

* Add debug-only use of new AssemblyBuilder.Save in Regex.CompileToAssembly

To aid in debugging RegexCompiler issues and to help vet the new AssemblyBuilder.Save support.

* Fix IL2121 warnings

---------

Co-authored-by: Sven Boemer <[email protected]>