Remove unused PInvokeTransitionFrame_MAX_SIZE and PInvokeTransitionFrame_SaveRegs_count macros

[Copilot]

PInvokeTransitionFrame_MAX_SIZE and its dependency PInvokeTransitionFrame_SaveRegs_count (defined conditionally for AMD64/x86/ARM) in src/coreclr/nativeaot/Runtime/inc/rhbinder.h are never referenced anywhere else in the repository.

Description

Removes 12 lines of dead code from rhbinder.h:

• PInvokeTransitionFrame_SaveRegs_count — the three platform-conditional definitions (TARGET_AMD64=9, TARGET_X86=6, TARGET_ARM=9)
• PInvokeTransitionFrame_MAX_SIZE — the macro consuming the above

Original prompt

Summary

The macro PInvokeTransitionFrame_MAX_SIZE is defined in src/coreclr/nativeaot/Runtime/inc/rhbinder.h but is never referenced or used anywhere else in the repository. It should be removed as dead code.

Details

Definition location

src/coreclr/nativeaot/Runtime/inc/rhbinder.h

#define PInvokeTransitionFrame_MAX_SIZE (sizeof(PInvokeTransitionFrame) + (POINTER_SIZE * PInvokeTransitionFrame_SaveRegs_count))

This macro depends on PInvokeTransitionFrame_SaveRegs_count, which is itself only defined for TARGET_AMD64, TARGET_X86, and TARGET_ARM — meaning PInvokeTransitionFrame_MAX_SIZE is only conditionally meaningful for those three targets.

A code search across the entire dotnet/runtime repository confirms that PInvokeTransitionFrame_MAX_SIZE is never used outside of its definition.

Task

• Remove the #define PInvokeTransitionFrame_MAX_SIZE ... line from src/coreclr/nativeaot/Runtime/inc/rhbinder.h.
• Also remove the PInvokeTransitionFrame_SaveRegs_count definitions (for TARGET_AMD64, TARGET_X86, and TARGET_ARM) immediately above it, if they are also not used anywhere else in the repository.
• Verify no other files reference either macro before removing them.

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Pull request overview

Removes dead, unused macros from the NativeAOT runtime binder header (rhbinder.h) to reduce unused platform-conditional code and avoid maintaining unused ABI-related constants.

Changes:

• Remove PInvokeTransitionFrame_SaveRegs_count platform-conditional macro definitions.
• Remove PInvokeTransitionFrame_MAX_SIZE macro that depended on PInvokeTransitionFrame_SaveRegs_count.