[x86] Do not support hardware intrinsics on x86 unix

[kvochko]

On x86 unix jit is compiled without hardware intrinsic support

coreclr/src/jit/CMakeLists.txt

Line 7 in 5e4e286

if (CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64 OR (CLR_CMAKE_TARGET_ARCH_I386 AND NOT CLR_CMAKE_PLATFORM_UNIX))

but System.Private.CoreLib is built with it. This leads to errors, like:

GC/API/GCHandle/Alloc_neg2/Alloc_neg2.sh
               BEGIN EXECUTION
               /dotnet/corert/tests/../Tools/msbuild.sh /m /p:IlcPath=/dotnet/corert/tests/../bin/Linux.armel.Debug /p:IlcTarget=armel /p:LinkerFlags=-target arm-linux-gnueabi --sysroot=/dotnet/corert/tests/../cross/rootfs/armel -B/dotnet/corert/tests/../cross/rootfs/armel/usr/lib/gcc/armv7l-tizen-linux-gnueabi/6.2.1 -L/dotnet/corert/tests/../cross/rootfs/armel/usr/lib/gcc/armv7l-tizen-linux-gnueabi/6.2.1 -lssl -lcrypto -lkeyutils -v -Wl,-v /p:Configuration=Debug Test.csproj
               Microsoft (R) Build Engine version 15.8.166+gd4e8d81a88 for .NET Core
               Copyright (C) Microsoft Corporation. All rights reserved.
               
                 /usr/bin/clang-3.9
                 Generating native code
                 
                 Unhandled Exception: System.InvalidProgramException: The JIT compiler encountered invalid IL code or an internal limitation.
                    at System.Runtime.Intrinsics.X86.Lzcnt.get_IsSupported()
                    at System.Buffers.Utilities.SelectBucketIndex(Int32 bufferSize)
                    at System.Buffers.TlsOverPerCoreLockedStacksArrayPool`1.Rent(Int32 minimumLength)
                    at System.Text.ValueUtf8Converter.ConvertAndTerminateString(ReadOnlySpan`1 value)
                    at Interop.Sys.Stat(ReadOnlySpan`1 path, FileStatus& output)
                    at System.IO.FileSystem.FileExists(ReadOnlySpan`1 fullPath, Int32 fileType, ErrorInfo& errorInfo)
                    at System.IO.FileSystem.FileExists(ReadOnlySpan`1 fullPath)
                    at System.IO.File.Exists(String path)
                    at System.CommandLine.ArgumentSyntax.ParseResponseFile(String fileName)
                    at System.CommandLine.ArgumentLexer.ExpandResponseFiles(IEnumerable`1 args, Func`2 responseFileReader)+MoveNext()
                    at System.CommandLine.ArgumentLexer.Lex(IEnumerable`1 args, Func`2 responseFileReader)
                    at System.CommandLine.ArgumentParser..ctor(IEnumerable`1 arguments, Func`2 responseFileReader)
                    at System.CommandLine.ArgumentSyntax.get_Parser()
                    at System.CommandLine.ArgumentSyntax.DefineOption[T](String name, T defaultValue, Func`2 valueConverter)
                    at System.CommandLine.ArgumentSyntax.DefineOption[T](String name, T& value, Func`2 valueConverter, String help)
                    at System.CommandLine.ArgumentSyntax.DefineOption(String name, Boolean& value, String help)
                    at ILCompiler.Program.<>c__DisplayClass44_0.<ParseCommandLine>b__0(ArgumentSyntax syntax)
                    at System.CommandLine.ArgumentSyntax.Parse(IEnumerable`1 arguments, Action`1 defineAction)
                    at ILCompiler.Program.ParseCommandLine(String[] args)
                    at ILCompiler.Program.Run(String[] args)
                    at ILCompiler.Program.Main(String[] args)
                 Aborted (core dumped)

This change disables support for hardware intrinsics in System.Private.CoreLib on x86 Unix.

[tannergooding]

What is currently broken if we do the reverse and just enable them on x86 Unix? Do any tests fail?

[kvochko]

This was the commit that originally disabled them - #8335, other than that I haven't looked much into it. @parjong do you know if the issues that required disabling them were resolved? Anyway I will try to run tests soon to see if there is any regression with intrinsics enabled.

[tannergooding]

Thanks! It would be nice if we had an issue tracking this if it turns out to not work, otherwise LGTM.

[tannergooding]

CC. @CarolEidt, @fiigii

[fiigii]

Hardware intrinsic is supported by x86/windows. Is there any plan to enable it on x86/Unix in the future?

[parjong]

@kvochko I can't remember the exact reason, but it took too much effort to enable AVX at that time. I'm not sure about the current status :)

[kvochko]

Ok, thanks! @fiigii I'm not aware of such plans, but I've opened an issue to track the fact that they are disabled

[fiigii]

Thanks, the change looks good.

[CarolEidt]

LGTM