[llvm] [AArch64][PAC] Support BLRA* instructions in SLS Hardening pass (PR #97605)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-rel-x86-64` running on `ml-opt-rel-x86-64-b1` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/185/builds/1311

Here is the relevant piece of the build log for the reference:
```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AArch64/speculation-hardening-sls-blra.mir' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
RUN: at line 1: /b/ml-opt-rel-x86-64-b1/build/bin/llc -verify-machineinstrs -mtriple=aarch64-none-linux-gnu      -start-before aarch64-sls-hardening -o - /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir      -asm-verbose=0  | /b/ml-opt-rel-x86-64-b1/build/bin/FileCheck /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir      --implicit-check-not=__llvm_slsblr_thunk_aa_x5_x8      --implicit-check-not=__llvm_slsblr_thunk_ab_x5_x8      --implicit-check-not=__llvm_slsblr_thunk_aaz_x5      --implicit-check-not=__llvm_slsblr_thunk_abz_x5
+ /b/ml-opt-rel-x86-64-b1/build/bin/llc -verify-machineinstrs -mtriple=aarch64-none-linux-gnu -start-before aarch64-sls-hardening -o - /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir -asm-verbose=0
+ /b/ml-opt-rel-x86-64-b1/build/bin/FileCheck /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir --implicit-check-not=__llvm_slsblr_thunk_aa_x5_x8 --implicit-check-not=__llvm_slsblr_thunk_ab_x5_x8 --implicit-check-not=__llvm_slsblr_thunk_aaz_x5 --implicit-check-not=__llvm_slsblr_thunk_abz_x5
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /b/ml-opt-rel-x86-64-b1/build/bin/llc -verify-machineinstrs -mtriple=aarch64-none-linux-gnu -start-before aarch64-sls-hardening -o - /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir -asm-verbose=0
1.	Running pass 'Function Pass Manager' on module '/b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir'.
2.	Running pass 'AArch64 sls hardening pass' on function '@__llvm_slsblr_thunk_aa_x0_x1'
 #0 0x000055f538d00fb8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x3d0cfb8)
 #1 0x000055f538cfe39c SignalHandler(int) Signals.cpp:0:0
 #2 0x00007f8241d3d140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x13140)
 #3 0x000055f537cab391 llvm::MachineInstr::addOperand(llvm::MachineFunction&, llvm::MachineOperand const&) (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x2cb7391)
 #4 0x000055f535f319a4 llvm::ThunkInserter<(anonymous namespace)::SLSHardeningInserter, (anonymous namespace)::ThunksSet>::run(llvm::MachineModuleInfo&, llvm::MachineFunction&) AArch64SLSHardening.cpp:0:0
 #5 0x000055f537c98147 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
 #6 0x000055f538298319 llvm::FPPassManager::runOnFunction(llvm::Function&) (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x32a4319)
 #7 0x000055f538298551 llvm::FPPassManager::runOnModule(llvm::Module&) (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x32a4551)
 #8 0x000055f53829913b llvm::legacy::PassManagerImpl::run(llvm::Module&) (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x32a513b)
 #9 0x000055f535a8c471 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#10 0x000055f5359872ce main (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0x9932ce)
#11 0x00007f8241829d0a __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x23d0a)
#12 0x000055f535a82a9a _start (/b/ml-opt-rel-x86-64-b1/build/bin/llc+0xa8ea9a)
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /b/ml-opt-rel-x86-64-b1/build/bin/FileCheck /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/AArch64/speculation-hardening-sls-blra.mir --implicit-check-not=__llvm_slsblr_thunk_aa_x5_x8 --implicit-check-not=__llvm_slsblr_thunk_ab_x5_x8 --implicit-check-not=__llvm_slsblr_thunk_aaz_x5 --implicit-check-not=__llvm_slsblr_thunk_abz_x5

--

********************


```

https://github.com/llvm/llvm-project/pull/97605