With this option we can pass to BOLT names of functions to be printed
through a file instead of specifying them all on command line.

Add more heuristics to check if a basic block is an AArch64 epilogue. We
assume instructions that load from stack or adjust stack pointer as
valid epilogue code sequence if and only if they immediately precede the
branch instruction that ends the basic block.

Remove internal undefined symbol tracking and instead rely on the
emission state of `MCSymbol` while processing data-to-code relocations.

Note that `CleanMCState` pass resets the state of all `MCSymbol`s prior
to code emission.

Refactor code that verifies external branch destinations and creates
secondary entry points.

The [previous patch](https://github.com/llvm/llvm-project/pull/163418)
has added a check to prevent adding an entry point into a constant
island, but only for successfully disassembled functions.

Because scanExternalRefs() is also called when a function fails to be
disassembled or is skipped, it can still attempt to add an entry point
at constant islands. The same issue may occur if without a check for it

So, this patch complements the 'constant island' check in
scanExternalRefs().

CreatePastEnd parameter had no effect on the label creation. Remove it.

Check whether AArch64 function code padding is valid,
and add an option to treat invalid code padding as error.

https://github.com/codespell-project/codespell
```bash
codespell bolt --skip="*.yaml,Maintainers.txt" --write-changes \
    --ignore-words-list=acount,alledges,ans,archtype,defin,iself,mis,mmaped,othere,outweight,vas
```

Reapply "[BOLT][AArch64] Handle OpNegateRAState to enable optimizing
binaries with pac-ret hardening (#120064)" (#162353)

This reverts commit c7d776b06897567e2d698e447d80279664b67d47.

#120064 was reverted for breaking builders.

Fix: changed the mismatched type in MarkRAStates.cpp to `auto`.

---

Original message:

OpNegateRAState is an AArch64-specific DWARF CFI used to change the value
of the RA_SIGN_STATE pseudoregister. The RA_SIGN_STATE register records
whether the current return address has been signed with PAC.

OpNegateRAState requires special handling in BOLT because its placement
depends on the function layout. Since BOLT reorders basic blocks during
optimization, these CFIs must be regenerated after layout is finalized.

This patch introduces two new passes:

- MarkRAStates (runs before optimizations): assigns a signedness annotation to each
  instruction based on OpNegateRAState CFIs in the input binary.

- InsertNegateRAStates (runs after optimizations): reads the annotations and emits
  new OpNegateRAState CFIs where RA state changes between instructions.

Design details are described in: `bolt/docs/PacRetDesign.md`.

Reverts llvm/llvm-project#120064.

@gulfemsavrun reported that the patch broke toolchain builders.