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
format(const DIERef & ref,raw_ostream & OS,StringRef Style)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
Decode(const DataExtractor & data,lldb::offset_t * offset_ptr)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
Encode(DataEncoder & encoder) const46 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