Adding GetTLSIndex cDAC implementation

[rcj1]

No description provided.

[Copilot]

Pull Request Overview

Implements cDAC support for retrieving the TLS index on a target runtime.

• Added the GetTLSIndex method in SOSDacImpl.cs with low-level reads, error handling, and debug assertions against the legacy DAC.
• Introduced new constants TlsIndex and TlsOutOfIndexes in the data contract for TLS globals.
• Exposed TLS_OUT_OF_INDEXES and g_TlsIndex in datadescriptor.h for cDAC consumption.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs	Implements GetTLSIndex logic, argument validation, and debug checks
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Constants.cs	Adds TlsIndex and TlsOutOfIndexes to the Globals contract
src/coreclr/debug/runtimeinfo/datadescriptor.h	Declares CDAC globals for TlsOutOfIndexes and TlsIndex

Comments suppressed due to low confidence (1)

src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs:1646

• Add unit tests for GetTLSIndex covering successful index retrieval, the S_FALSE case when TlsIndex == TlsOutOfIndexes, and error paths to ensure the implementation behaves as expected.

    int ISOSDacInterface.GetTLSIndex(uint* pIndex)

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[rcj1]

/ba-g android-x64 Release AllSubsets_CoreCLR timeout

[jkotas]

LGTM otherwise

[jkotas]

Thanks

[rcj1]

/ba-g baseservices-exceptions Work Item failure