[NativeAOT] Emit Align8 flag for thread statics

[filipnavara]

Fixes #103234
Contributes to #97729

[MichalStrehovsky]

Could you also make it so that we don't have GCStaticEETypes that only differ by RequiresAlign8 bit on platforms that don't have Align8 concept? (we don't set RequiresAlign8 on MethodTables on these platforms either).

[filipnavara]

Could you also make it so that we don't have GCStaticEETypes that only differ by RequiresAlign8 bit on platforms that don't have Align8 concept? (we don't set RequiresAlign8 on MethodTables on these platforms either).

The bool RequiresAlign8(this TypeDesc type) always returns false on platforms without the concept, ie. anything but ARM32 and WASM. The deduplication should happen in NodeCache automatically since you get the same key with requiresAlign8 == false.

Nevermind, I forgot that I didn't use RequiresAlign8(...) in the final version. Will fix.

[SingleAccretion]

Do dynamic (MakeGenericType) thread statics need any additional attention (e. g. a test)?

[filipnavara]

Do dynamic (MakeGenericType) thread statics need any additional attention (e. g. a test)?

Test would be nice. I am not really sure how these are treated internally in ILC / NAOT runtime, so I am not sure if I am qualified to check this.

[MichalStrehovsky]

Do dynamic (MakeGenericType) thread statics need any additional attention (e. g. a test)?

Test would be nice. I am not really sure how these are treated internally in ILC / NAOT runtime, so I am not sure if I am qualified to check this.

Something along these lines:

    private class ThreadStaticAlignCheck1<T>
    {
        [ThreadStatic]
        [FixedAddressValueType]
        internal static ReturnArea returnArea = default;
    }

    private class ThreadStaticAlignCheck2<T>
    {
        [ThreadStatic]
        [FixedAddressValueType]
        internal static ReturnArea returnArea = default;
    }

    public static void RunGeneric<T>()
    {
            // Assume that these are allocated sequentially, use a padding object of size 12 (mod 8 is not 0)
            // to move the alignment of the second AddressOfReturnArea in case the first is coincidentally aligned 8.
            var ts1Addr = ThreadStaticAlignCheck1<T>.returnArea.AddressOfReturnArea();
            var p = new Padder();
            var ts2Addr = ThreadStaticAlignCheck2<T>.returnArea.AddressOfReturnArea();

            if (((nint)ts1Addr) % 8 != 0)
                throw new Exception();
            if (((nint)ts2Addr) % 8 != 0)
                throw new Exception();
    }

    class Atom { }

And add this to Run:

typeof(ThreadStaticAlignmentTest).GetMethod("RunGeneric").MakeGenericMethod(GetAtom()).Invoke(null, []);

[MethodImpl(MethodImplOptions.NoInlining)]
static void GetAtom() => typeof(Atom);

[filipnavara]

Something along these lines:

Thanks, I will check it on my Raspberry Pi once I get to office.

[filipnavara]

Test added, it passes on my machine (tm).

[MichalStrehovsky]

/azp run runtime-nativeaot-outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[MichalStrehovsky]

/ba-g infra indicates failures, but the logs at https://helix.dot.net/api/2019-06-17/jobs/7c253045-5363-4f2c-a180-622d4c896b69/workitems/System.IO.FileSystem.DisabledFileLocking.Tests/console look good

[MichalStrehovsky]

Thank you!