[JonChesterfield]

The goto labels can exported much more directly using inline asm. Further, inline asm can now represent control flow, so you can define the labels in inline asm and the computed jump at the end of an opcode. That's pretty robust to compiler transforms. Just looked up an interpreter in that style:

#define LABEL_START(TAG) ns_##TAG : __asm__(".p2align 3\n.Lstart_" #TAG ":" :::)

#define LABEL_END(TAG) __asm__(".Lend_" #TAG ":\n")

#define PROLOGUE(TAG) LABEL_START(TAG); ip++

#define EPILOGUE(TAG) __asm__ goto("\tjmpq %0\n" "\t.Lend_" #TAG ":\n"::"r"((void)decode(ip))::ALL_LABELS())

Followed by opcodes implemented in this fashion:

  {
    PROLOGUE(add);
    {
      apply_opcode_ADD(&s->data_stack);
    }
    EPILOGUE(add);
  }

Because the labels are defined in assembly, not in C, accessing them from outside the function is straightforward. I wrote a whole load of these at some point, there's probably a version of those macros somewhere that compiles to jumps through a C computed goto as well.