JIT: Model GS cookie check in LSRA

[jakobbotsch]

Also switch the register used when generating the check if there is a tailcall in the block on x64. This allows us to enable fast tailcalls out of methods with GS cookie checks on x64.

Fix #119949

[jakobbotsch]

/azp run runtime-coreclr jitstress, runtime-coreclr libraries-jitstress

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Azure Pipelines successfully started running 2 pipeline(s).

[Copilot]

Pull Request Overview

This PR enables fast tail calls from methods that require GS (Guard Stack) security cookie checks on x64 by modeling the GS cookie check in LSRA (Linear Scan Register Allocator) and adapting register selection for tail call scenarios. Previously, fast tail calls were disabled for methods with GS cookie checks on x64 due to compatibility requirements.

• Removes the restriction that prevented fast tail calls from methods with GS cookie checks on x64
• Models GS cookie checks in LSRA to properly handle register allocation conflicts
• Introduces dynamic register selection for GS cookie checks based on whether a tail call is present

Reviewed Changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/JIT/opt/Tailcall/TailcallVerifyWithPrefix.il	Removes test case Condition17 that is no longer needed
src/coreclr/jit/targetriscv64.h	Replaces individual register definitions with register mask for GS cookie temps
src/coreclr/jit/targetloongarch64.h	Replaces individual register definitions with register mask for GS cookie temps
src/coreclr/jit/targetarm64.h	Replaces individual register definitions with register mask for GS cookie temps
src/coreclr/jit/targetarm.h	Replaces individual register definitions with register mask for GS cookie temps
src/coreclr/jit/morph.cpp	Removes x64-specific restriction preventing fast tail calls with GS cookie checks
src/coreclr/jit/lsraxarch.cpp	Adds logic to exclude GS cookie temp registers from control expression candidates for fast tail calls
src/coreclr/jit/lsrariscv64.cpp	Updates to use new centralized GS cookie temp register selection
src/coreclr/jit/lsraloongarch64.cpp	Updates to use new centralized GS cookie temp register selection
src/coreclr/jit/lsrabuild.cpp	Adds LSRA modeling for GS cookie checks by inserting register kills
src/coreclr/jit/lsraarmarch.cpp	Updates to use new centralized GS cookie temp register selection
src/coreclr/jit/lower.cpp	Removes assertion that prevented GS cookie checks in fast tail calls on x64
src/coreclr/jit/codegenxarch.cpp	Simplifies GS cookie check implementation and removes tail call specific logic
src/coreclr/jit/codegenriscv64.cpp	Updates GS cookie check to use dynamic register selection
src/coreclr/jit/codegenloongarch64.cpp	Updates GS cookie check to use dynamic register selection
src/coreclr/jit/codegeninterface.h	Adds declaration for new genGetGSCookieTempRegs method
src/coreclr/jit/codegencommon.cpp	Implements centralized logic for GS cookie temp register selection
src/coreclr/jit/codegenarmarch.cpp	Updates GS cookie check to use dynamic register selection
src/coreclr/jit/codegen.h	Updates genEmitGSCookieCheck method signature to use tailCall parameter

[jakobbotsch]

This particular test was relying on no tailcall to happen from method with unsafe local in it.

[jakobbotsch]

PTAL @dotnet/jit-contrib

Diffs. Some minor size regressions because the proper encoding of the kill seems to perturb LSRA a little bit, making it pick some other registers with larger encoding. Rarely some improvements when we now tailcall out of some more methods.