Method embed_label_delta

lib/asmjit/asmjit/core/assembler.cpp:324–393

}

Error BaseAssembler::embed_label_delta(const Label& label, const Label& base, size_t data_size) {
  if (ASMJIT_UNLIKELY(!_code)) {
    return report_error(make_error(Error::kNotInitialized));
  }

  if (ASMJIT_UNLIKELY(!Support::bool_and(_code->is_label_valid(label), _code->is_label_valid(base)))) {
    return report_error(make_error(Error::kInvalidLabel));
  }

  LabelEntry& label_entry = _code->label_entry_of(label);
  LabelEntry& base_entry = _code->label_entry_of(base);

  if (data_size == 0) {
    data_size = register_size();
  }

  if (ASMJIT_UNLIKELY(!Support::is_power_of_2_up_to(data_size, 8u))) {
    return report_error(make_error(Error::kInvalidOperandSize));
  }

  CodeWriter writer(this);
  ASMJIT_PROPAGATE(writer.ensure_space(this, data_size));

#ifndef ASMJIT_NO_LOGGING
  if (_logger) {
    StringTmp<256> sb;
    sb.append('.');
    Formatter::format_data_type(sb, _logger->flags(), arch(), data_type_id_by_size_table[data_size]);
    sb.append(" (");
    Formatter::format_label(sb, FormatFlags::kNone, this, label.id());
    sb.append(" - ");
    Formatter::format_label(sb, FormatFlags::kNone, this, base.id());
    sb.append(")\n");
    _logger->log(sb);
  }
#endif

  // If both labels are bound within the same section it means the delta can be calculated now.
  if (label_entry.is_bound() && base_entry.is_bound() && label_entry.section_id() == base_entry.section_id()) {
    uint64_t delta = label_entry.offset() - base_entry.offset();
    writer.emit_value_le(delta, data_size);
  }
  else {
    RelocEntry* re;
    Error err = _code->new_reloc_entry(Out(re), RelocType::kExpression);
    if (ASMJIT_UNLIKELY(err != Error::kOk)) {
      return report_error(err);
    }

    Expression* exp = _code->_arena.new_oneshot<Expression>();
    if (ASMJIT_UNLIKELY(!exp)) {
      return report_error(make_error(Error::kOutOfMemory));
    }

    exp->reset();
    exp->op_type = ExpressionOpType::kSub;
    exp->set_value_as_label_id(0, label.id());
    exp->set_value_as_label_id(1, base.id());