SDT_NOP
instr[-1] = SDT_NOP;
instr[0] = SDT_NOP;
instr[1] = SDT_NOP;
instr[2] = SDT_NOP;
instr[SDT_OFF_RET_IDX] = is_tailcall ? SDT_RET : SDT_NOP;
*instr = SDT_NOP;