1 //===-- DIERef.cpp --------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "DIERef.h" 10 #include "lldb/Utility/DataEncoder.h" 11 #include "lldb/Utility/DataExtractor.h" 12 #include "llvm/Support/Format.h" 13 14 using namespace lldb; 15 using namespace lldb_private; 16 17 void llvm::format_provider<DIERef>::format(const DIERef &ref, raw_ostream &OS, 18 StringRef Style) { 19 if (ref.dwo_num()) 20 OS << format_hex_no_prefix(*ref.dwo_num(), 8) << "/"; 21 OS << (ref.section() == DIERef::DebugInfo ? "INFO" : "TYPE"); 22 OS << "/" << format_hex_no_prefix(ref.die_offset(), 8); 23 } 24 25 constexpr uint32_t k_dwo_num_mask = 0x3FFFFFFF; 26 constexpr uint32_t k_dwo_num_valid_bitmask = (1u << 30); 27 constexpr uint32_t k_section_bitmask = (1u << 31); 28 29 llvm::Optional<DIERef> DIERef::Decode(const DataExtractor &data, 30 lldb::offset_t *offset_ptr) { 31 const uint32_t bitfield_storage = data.GetU32(offset_ptr); 32 uint32_t dwo_num = bitfield_storage & k_dwo_num_mask; 33 bool dwo_num_valid = (bitfield_storage & (k_dwo_num_valid_bitmask)) != 0; 34 Section section = (Section)((bitfield_storage & (k_section_bitmask)) != 0); 35 // DIE offsets can't be zero and if we fail to decode something from data, 36 // it will return 0 37 dw_offset_t die_offset = data.GetU32(offset_ptr); 38 if (die_offset == 0) 39 return llvm::None; 40 if (dwo_num_valid) 41 return DIERef(dwo_num, section, die_offset); 42 else 43 return DIERef(llvm::None, section, die_offset); 44 } 45 46 void DIERef::Encode(DataEncoder &encoder) const { 47 uint32_t bitfield_storage = m_dwo_num; 48 if (m_dwo_num_valid) 49 bitfield_storage |= k_dwo_num_valid_bitmask; 50 if (m_section) 51 bitfield_storage |= k_section_bitmask; 52 encoder.AppendU32(bitfield_storage); 53 static_assert(sizeof(m_die_offset) == 4, "m_die_offset must be 4 bytes"); 54 encoder.AppendU32(m_die_offset); 55 } 56