@EgorBot -intel -arm64 -perf

using System;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkRunner.Run<Bench>(args: args);

public class Bench
{
    struct S;

    [Benchmark]
    public Type Nested() => typeof(S).DeclaringType;

    [Benchmark]
    public Type NotNested() => typeof(Bench).DeclaringType;

    [Benchmark]
    public Type RefElementType() => typeof(Bench[]).GetElementType();

    [Benchmark]
    public Type ValueElementType() => typeof(S[]).GetElementType();
}

@EgorBot -x64 -arm64 -profiler

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

public class Bench
{
    struct S;

    [Benchmark]
    public Type Nested() => typeof(S).DeclaringType;

    [Benchmark]
    public Type NotNested() => typeof(Bench).DeclaringType;

    [Benchmark]
    public Type RefElementType() => typeof(Bench[]).GetElementType();

    [Benchmark]
    public Type ValueElementType() => typeof(S[]).GetElementType();
}

@AaronRobinsonMSFT the bot complained that -profiler flag should be used when there are not more than 3 [Benchmark] attributes. I think I should improve error reporting 🙂

@EgorBot -x64 -arm64

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

public class Bench
{
    struct S;

    [Benchmark]
    public Type Nested() => typeof(S).DeclaringType;

    [Benchmark]
    public Type NotNested() => typeof(Bench).DeclaringType;

    [Benchmark]
    public Type RefElementType() => typeof(Bench[]).GetElementType();

    [Benchmark]
    public Type ValueElementType() => typeof(S[]).GetElementType();
}

@EgorBot -x64 -arm64 -profiler

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

public class Bench
{
    struct S;

    [Benchmark]
    public Type RefElementType() => typeof(Bench[]).GetElementType();

    [Benchmark]
    public Type ValueElementType() => typeof(S[]).GetElementType();
}

@jkotas Looks like removing that IsArray check from GetDeclaringType() is causing linker legs to fail. Any thoughts?

I'll investigate the x86 leg tomorrow.

I'll investigate the x86 leg tomorrow.

This is failing in all PRs: #110127

Looks like removing that IsArray check from GetDeclaringType() is causing linker legs to fail. Any thoughts?

The failures are caused by the linker assuming that instances of RuntimeType and RuntimeAssembly types are never allocated. The linker is replacing checks like if (assembly is RuntimeAssembly) by if (false) that is causing inscrutable failures.

The RuntimeTypeHandle.GetRuntimeTypeFromHandle call under the IsArray check is what makes the linker think that RuntimeType may be allocated. When the call is deleted as side-effect of deleting the IsArray check, the things fall apart. Of course, depending on a random call in the middle of reflection stack from keeping RuntimeType type alive is super fragile.

The problem is caused by the fact that the runtime allocates RuntimeType instances without running constructor. It is ok since the constructor would be no-op anyway, but it is confusing the linker. I think the proper fix is to add an entry for RuntimeType and RuntimeAssembly constructors under #if FOR_ILLINK to corelib.h to signal to the linker that the VM creates instances of these types. Once you do that, the linker tests should be passing with the IsArray check deleted.

/ba-g "Failure is dotnet/dnceng#3879. Not waiting for timeout."