Fix gtGetClassHandle for static fields (R2R only)

[EgorBo]

Closes #74000

It turns out gtGetClassHandle used to always return nullptr for such static field loads in R2R (here)

Codegen diff for sample in #74000: https://www.diffchecker.com/AjNP6YTx

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Issue Details

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Closes #74000

It turns out gtGetClassHandle used to always return nullptr for such static field loads in R2R (here)

Codegen diff for sample in ttps://github.com//issues/74000: https://www.diffchecker.com/AjNP6YTx

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

[AndyAyersMS]

Is the comment you deleted no longer true?

If so, there may be other assumptions like this in the jit code.

[EgorBo]

Is the comment you deleted no longer true?

If so, there may be other assumptions like this in the jit code.

Looks like gtIsStaticGCBaseHelperCall is only used in one place (was added by you in dotnet/coreclr#20447) - no idea what exactly changed, maybe some refactoring or something like that but for that static field

    static IFoo theFoo = new Program();

it looks like

IND
  ADD
    CALL CORINFO_HELP_READYTORUN_STATIC_BASE
    8 [FldSeq]

so it's not really opaque and returns nullptr for gtGetClassHandle. Maybe it's NativeAOT specific?

For this PR I am waiting for SPMI to fix itself to re-run and see if there any diffs

[SingleAccretion]

FWIW, the shape of access to static fields hasn't changed for a very long time (one exception being the attachment of field sequences to outer addresses for boxed statics, which are not relevant here).

Also, I believe the "is static base" check can be simply deleted if there's not a correctness (versioning resilience?) reason we cannot look at declared types of statics under R2R. The field sequence check should be sufficient.

[AndyAyersMS]

Odd, what you have now is more or less the way I wrote it initially, long ago, but then revised it. But I can't find any notes from back then so I don't recall why I changed things.

Nothing else calls gtIsStaticGCBaseHelperCall so perhaps it can be removed.

[EgorBo]

/azp list

[EgorBo]

/azp run runtime-coreclr r2r, runtime-coreclr crossgen2, runtime-coreclr crossgen2 outerloop, runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 4 pipeline(s).

[EgorBo]

Oh, forgot about this one, will address the feedback tomorrow

[EgorBo]

@AndyAyersMS PTAL, a small clean up, diffs (in crossgen2 collections): https://dev.azure.com/dnceng-public/public/_build/results?buildId=38038&view=ms.vss-build-web.run-extensions-tab