Span: DangerousCreate should avoid argument validation

[ahsonkhan]

For Span/ReadOnlySpan DangerousCreate method, should we remove the following test cases to increase performance:

• SpanTests - DangerousCreateNullObject
• SpanTests - DangerousCreateBadLength
• ReadOnlySpanTests - DangerousCreateNullObject
• ReadOnlySpanTests - DangerousCreateBadLength

It was suggested that the Fast and Slow Span implementations should not do the check/throw on null object or negative lengths to speed up creation of the instance of Span/ReadOnlySpan.

That is, these checks should be removed:

        public static ReadOnlySpan<T> DangerousCreate(object obj, ref T objectData, int length)
        {
            if (obj == null)
                ThrowHelper.ThrowArgumentNullException(ExceptionArgument.obj);
            if (length < 0)
                ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.length);

Should they be removed?

[AlexGhiondea]

@KrzysztofCwalina is this something you are working on?

[karelz]

@KrzysztofCwalina ping?

[ahsonkhan]

Next step: Do the work highlighted in the original issue post. Should be simple to fix.

Essentially remove the checks in the below methods and the corresponding tests:

https://github.com/dotnet/corefx/blob/master/src/System.Memory/src/System/Span.cs#L139
https://github.com/dotnet/corefx/blob/master/src/System.Memory/src/System/ReadOnlySpan.cs#L139

https://github.com/dotnet/coreclr/blob/master/src/mscorlib/src/System/Span.cs#L147
https://github.com/dotnet/coreclr/blob/master/src/mscorlib/src/System/ReadOnlySpan.cs#L130

[WinCPP]

@karelz @ahsonkhan May I work on this?

[ahsonkhan]

Go for it :)

[WinCPP]

Thanks! Working on this.

…

On Fri, Mar 24, 2017 at 1:20 AM, Ahson Ahmed Khan ***@***.***> wrote: Go for it :) — You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://github.com/dotnet/corefx/issues/14486#issuecomment-288839943>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIh_MmViR9eUlg_1JyRAfOazPfmd4MI8ks5ros0hgaJpZM4LMW0W> .