[cDAC] ARM Stackwalking

[max-charlamb]

Changes

IStackWalk

• Implements managed ARMUnwinder
• Adds ARMContext
• Adds ARMFrameHandler
  • Verified all relevant Frames [cDAC] Stackwalking support all Frame types #114019

General ARM32 conversion fixes

Changes done in separate PR: #116720

• DAC GetThreadData properly converts firstNestedException to a CLRDATA_ADDRESS
• CodePointerUtils.CodePointerFromAddress properly handles TargetCodePointer.Null case. Previously it would append the thumb bit causing logic checks to fail.

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[Copilot]

Pull Request Overview

This PR adds ARM stackwalking support by introducing an ARM-specific unwinder, context, and frame handler along with associated type descriptor and documentation updates. The key changes include:

• Implementation of ARMUnwinder, ARMContext, and ARMFrameHandler to support ARM stackwalking.
• Updates to the InlinedCallFrame to include the new SPAfterProlog field for ARM.
• Adjustments to data descriptors and documentation to accommodate ARM32 specifics.

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Frames/InlinedCallFrame.cs	Adds SPAfterProlog field initialization for ARM.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/FrameHandling/FrameIterator.cs	Introduces ARM frame handling by mapping ARMContext to ARMFrameHandler.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/FrameHandling/ARMFrameHandler.cs	Implements ARM specific handling for inlined call frames and faulting exception frames.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/Context/ARMContext.cs	Provides a full ARM-specific context struct implementation.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/Context/ARM/LookupValues.cs	Introduces lookup tables using modern collection initialization syntax.
src/coreclr/debug/runtimeinfo/datadescriptor.h	Adds ARM-specific type definitions for the DAC.
docs/design/datacontracts/StackWalk.md	Updates documentation to describe the new SPAfterProlog field for ARM.