Pass exact context to getMethodInfo

[EgorBo]

Basically, it's Andy's patch that he never landed and asked me to (with some modifications).

Closes #88021

bool Test() => EqualityComparer<string>.Default.Equals("str", "str");

New codegen:

; Method Prog:Foo():bool:this
       mov      eax, 1
       ret      
; Total bytes of code: 6

It is also needed for #87847

[ghost]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
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Issue Details

---

Basically, it's Andy's patch that he never landed and asked me to.

Closes #88021

bool Test() => EqualityComparer<string>.Default.Equals("str", "str");

New codegen:

; Method Prog:Foo():bool:this
       mov      eax, 1
       ret      
; Total bytes of code: 6

Author:	EgorBo
Assignees:	EgorBo
Labels:	area-CodeGen-coreclr
Milestone:	-

[hez2010]

Wow I got some impressive performance improvements in my local benchmark.

But there's still some weird codegen which is unnecessary.

For example:

bool Test() => new Foo(1, "hello", "test") == new Foo(1, "test", "hello");

record struct Foo(int x, string y, string z);

The codegen for Test is

G_M50849_IG01:  ;; offset=0000H
						;; size=0 bbWeight=1.00 PerfScore 0.00
G_M50849_IG02:  ;; offset=0000H
       xor      eax, eax
       je       SHORT G_M50849_IG04
						;; size=4 bbWeight=1.00 PerfScore 1.25
G_M50849_IG03:  ;; offset=0004H
       xor      eax, eax
       jmp      SHORT G_M50849_IG05
						;; size=4 bbWeight=0.50 PerfScore 1.12
G_M50849_IG04:  ;; offset=0008H
       xor      eax, eax
						;; size=2 bbWeight=0.50 PerfScore 0.12
G_M50849_IG05:  ;; offset=000AH
       ret      
						;; size=1 bbWeight=1 PerfScore 1.00

which is effectively equivalent to:

       xor      eax, eax
       ret      

[EgorBo]

/azp run runtime-coreclr pgo

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[EgorBo]

/azp run runtime-coreclr outerloop, runtime-coreclr jitstress, runtime-extra-platforms, runtime-coreclr pgostress

[azure-pipelines]

Azure Pipelines successfully started running 4 pipeline(s).

[EgorBo]

@AndyAyersMS @jakobbotsch PTAL JIT side - it should be ready now, CI failures are not related

[EgorBo]

/azp run runtime-coreclr outerloop, runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[jkotas]

This won't work correctly for non-shared generic methods on shared generic types.

For example, G<string>.M<int>. GetTypicalMethodDefinition will drop the method instantiation, so we will end up with G<string>.M<T>. I am not sure whether this problem is reachable in practice currently.

[EgorBo]

I've just pushed a change:

MethodDesc methodTypicalDef = method.GetTypicalMethodDefinition();
if (methodTypicalDef.RequiresInstMethodDescArg())
{
    // Presumably, a rare case: we had MyClass<T1>.Foo<int>() method and
    // GetTypicalMethodDefinition() converted it to MyClass<T1>.Foo<T2>
}
else
{
    method = _compilation.TypeSystemContext.GetMethodForInstantiatedType(methodTypicalDef, instantiatedCtxType);
}

is it enough?

[EgorBo]

/azp run runtime-coreclr outerloop, runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[jkotas]

This crash looks related to the change: https://helix.dot.net/api/2019-06-17/jobs/47d2c98f-aa2e-4f5c-a38b-b6fc165d4b0b/workitems/System.Runtime.CompilerServices.Unsafe.Tests/console

[EgorBo]

This crash looks related to the change: https://helix.dot.net/api/2019-06-17/jobs/47d2c98f-aa2e-4f5c-a38b-b6fc165d4b0b/workitems/System.Runtime.CompilerServices.Unsafe.Tests/console

Looks like it is not since it can be found in other runs e.g. https://dev.azure.com/dnceng-public/public/_build/results?buildId=327970&view=ms.vss-test-web.build-test-results-tab&runId=6761902&resultId=150352&paneView=dotnet-dnceng.dnceng-build-release-tasks.helix-test-information-tab - I'll file an issue (#88339)

(PS: would love NativeAOT Libraries tests to have its own pipeline to avoid running Mono workloads)

[EgorBo]

@jkotas anything else to be done here?

[jkotas]

LGTM!