ZJIT: A64: Remove nop padding after conditional branchesHEADmaster

Previously, there were a lot of nops after conditional branches. They
come from branch to LIR labels:

    ./miniruby --zjit-call-threshold=1 --zjit-dump-disasm -e 'Object || String'

    # Insn: v14 CheckInterrupts
    # RUBY_VM_CHECK_INTS(ec)
      ldur w2, [x20, #0x20]
      tst w2, w2
      b.ne #0x120900278
      nop
      nop
      nop
      nop
      nop
    # Insn: v15 Test v11
      tst x0, #-5
      mov x2, #0
      mov x3, #1
      csel x2, x2, x3, eq
    # Insn: v16 IfTrue v15, bb3(v6, v11)
      tst x2, x2
      b.eq #0x120900198
      nop
      nop
      nop
      nop
      nop

They gunk up the disassembly and can't be helpful for speed. This commit
removes them. I think they were accidentally inherited from certain YJIT
branches that require padding for patching. ZJIT doesn't have these
requirements.

Use a single branch instruction for conditional branches to labels; Jmp
already uses a single `B` instruction. This will work for assemblers
that generate less than ~260,000 instructions -- plenty.

Let the CodeBlock::label_ref() callback return a failure, so we can
fail compilation instead of panicking in case we do get large offsets.

0 files changed, 0 insertions, 0 deletions