While printing functions, expand --print-only flag to accept section
names. E.g., "--print-only=\.init" will only print functions from
".init" section.

Move handling of all internal calls into the designated pass. Preserve
NOPs and mark functions as non-simple on non-X86 platforms.

CFI programs may have more saves than restores and this is completely
benign from BOLT's perspective. Reduce the verbosity and print the
warning only under `-v=1` and above.

clang-15 can produce binaries with mismatched RememberState/RestoreState
CFIs. This is benign for unwinding, so replace an assert with a warning.

Detect and support fixed PIC indirect jumps of the following form:
```
movslq  En(%rip), %r1
leaq  PIC_JUMP_TABLE(%rip), %r2
addq  %r2, %r1
jmpq  *%r1
```

with PIC_JUMP_TABLE that looks like following:

```
  JT:  ----------
   E1:| L1 - JT  |
      |----------|
   E2:| L2 - JT  |
      |----------|
      |          |
         ......
   En:| Ln - JT  |
       ----------
```

The code could be produced by compilers, see
https://github.com/llvm/llvm-project/issues/91648.

Test Plan: updated jump-table-fixed-ref-pic.test

Reviewers: maksfb, ayermolo, dcci, rafaelauler

Reviewed By: rafaelauler

Pull Request: https://github.com/llvm/llvm-project/pull/91667

GNU assembler 2.26 introduced the .cfi_label directive. It does not
expand to any CFI instructions, but defines a label in
.eh_frame/.debug_frame, which can be used by runtime patching code to
locate the FDE. .cfi_label is not allowed for CIE's initial
instructions, and can therefore be used to force the next instruction to
be placed in a FDE instead of a CIE.

In glibc since 2018, sysdeps/riscv/start.S utilizes .cfi_label to force
DW_CFA_undefined to be placed in a FDE. arc/csky/loongarch ports have
copied this use.
```
.cfi_startproc
// DW_CFA_undefined is allowed for CIE's initial instructions.
// Without .cfi_label, gas would place DW_CFA_undefined in a CIE.
.cfi_label .Ldummy
.cfi_undefined ra
.cfi_endproc
```

No CFI instruction is associated with .cfi_label, so the `case
MCCFIInstruction::OpLabel:` code in BOLT is unreachable and onlt to make
-Wswitch happy.

Close #97222

Pull Request: https://github.com/llvm/llvm-project/pull/97922

9d0754ada5dbbc0c009bcc2f7824488419cc5530 dropped MC support required for
optimal macro-fusion alignment in BOLT. Remove the support in BOLT as
performance measurements with large binaries didn't show a significant
improvement.

Test Plan:
macro-fusion alignment was never upstreamed, so no upstream tests are
affected.

`isUnsupportedBranch` was renamed (and inverted)  to `isReversibleBranch`, as that was how it was being used. But one use  in `BinaryFunction::disassemble` was using the original meaning to detect unsupported branches, and the `isUnsupportedBranch` had 2 separate semantic checks.

Move the unsupported branch check from `isReversibleBranch` to a new entry point: `isUnsupportedInstruction`. Call that from `BinaryFunction::disassemble`.

Move the dynamic branch check from X86's isReversibleBranch to the base class, as it is not an architecture-specific check.

Remove unnecessary `isReversibleBranch` calls from Instrumentation and X86 MCPlusBuilder.

Alternative instruction sequences in the Linux kernel can modify the
stack and thus they need their own ORC unwind entries. Since there's
only one ORC table, it has to be "shared" among multiple instruction
sequences. The kernel achieves this by putting a restriction on
instruction boundaries. If ORC state changes at a given IP, only one of
the alternative sequences can have an instruction starting/ending at
this IP. Then, developers can insert NOPs to guarantee the above
requirement is met.

The most common use of ORC with alternatives is "pushf; pop %rax"
sequence used for paravirtualization. Note that newer kernel versions
no longer use .parainstructions; instead, they utilize alternatives for
the same purpose.

Before we implement a better support for alternatives, we can safely
skip ORC entries associated with them.

Fixes #87052.

If a function has no CFI program attached to it, do not print redundant
empty CFI state for every basic block.