Add constrained support for calls

[BrzVlad]

Plus minor refactor around StackInfo. Remove size field since it doesn't look like we will ever use it.

Currently there is no support for boxing with generic shared types.

Fixes Loader/classloader/regressions/208900

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[Copilot]

Pull Request Overview

This PR adds support for constrained calls by introducing a new box.ptr opcode and associated handling, refactors StackInfo to remove its unused size field, and implements a shared EmitBox helper to consolidate boxing logic.

• Introduce INTOP_BOX_PTR in intops.def and handle it in the interpreter loop (interpexec.cpp).
• Refactor StackInfo (remove size), update all construction sites, and add EmitBox in compiler.h/compiler.cpp.
• Update EmitCall to handle thisTransform cases including boxing/dereferencing, and remove <CLRTestPriority> from the test project.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/tests/Loader/classloader/regressions/208900/bug.csproj	Removed outdated <CLRTestPriority> property
src/coreclr/vm/interpexec.cpp	Added INTOP_BOX_PTR case and updated unboxed/boxed data logic
src/coreclr/interpreter/intops.def	Defined new OPDEF(INTOP_BOX_PTR, "box.ptr", ...)
src/coreclr/interpreter/compiler.h	Removed size from StackInfo; added EmitBox declaration and renamed EmitCall param
src/coreclr/interpreter/compiler.cpp	Updated PushTypeExplicit, EmitConv, clause init, and EmitCall; implemented EmitBox helper

Comments suppressed due to low confidence (2)

src/coreclr/interpreter/compiler.h:499

• [nitpick] The parameter clsHnd is the unboxed type handle, which may be confusing. Consider renaming it to unboxedClsHnd to make its purpose clearer.

void    EmitBox(StackInfo* pStackInfo, CORINFO_CLASS_HANDLE clsHnd, bool argByRef);

src/coreclr/interpreter/compiler.cpp:2898

• [nitpick] Add a brief comment above EmitBox explaining that clsHnd refers to the unboxed type being boxed and that argByRef controls whether to use box or box.ptr.

void InterpCompiler::EmitBox(StackInfo* pStackInfo, CORINFO_CLASS_HANDLE clsHnd, bool argByRef)

[BrzVlad]

@davidwrighton When using gshared types that need to be resolved at runtime, we currently add specific opcodes to do the resolve and store the result in a var. I'm not really a big fan of this approach because it requires indirection, bloats the code with instructions and it might require to add a fair amount of new opcodes, for the gshared version that loads the type from an argument var. I'm thinking that a less invasive approach could be to have the same format for all instructions and when an instruction receives a generic handle as a data item, it either represents the actual type, or if the handle pointer is tagged it represents some other data that is used to resolve the type at runtime as part of the instruction execution. What do you think about this alternative approach ? I could give it a go if it is not on your radar.

[janvorli]

LGTM modulo the test priority change.