1 //===-- DWARFCompileUnit.cpp ------------------------------------*- C++ -*-===//
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 "DWARFCompileUnit.h"
10 
11 #include "SymbolFileDWARF.h"
12 #include "lldb/Utility/Stream.h"
13 
14 using namespace lldb;
15 using namespace lldb_private;
16 
17 DWARFCompileUnit::DWARFCompileUnit(SymbolFileDWARF *dwarf2Data)
18     : DWARFUnit(dwarf2Data) {}
19 
20 DWARFUnitSP DWARFCompileUnit::Extract(SymbolFileDWARF *dwarf2Data,
21                                       const DWARFDataExtractor &debug_info,
22                                       lldb::offset_t *offset_ptr) {
23   // std::make_shared would require the ctor to be public.
24   std::shared_ptr<DWARFCompileUnit> cu_sp(new DWARFCompileUnit(dwarf2Data));
25 
26   cu_sp->m_offset = *offset_ptr;
27 
28   if (debug_info.ValidOffset(*offset_ptr)) {
29     dw_offset_t abbr_offset;
30     const DWARFDebugAbbrev *abbr = dwarf2Data->DebugAbbrev();
31     cu_sp->m_length = debug_info.GetDWARFInitialLength(offset_ptr);
32     cu_sp->m_is_dwarf64 = debug_info.IsDWARF64();
33     cu_sp->m_version = debug_info.GetU16(offset_ptr);
34 
35     if (cu_sp->m_version == 5) {
36       cu_sp->m_unit_type = debug_info.GetU8(offset_ptr);
37       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
38       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
39 
40       if (cu_sp->m_unit_type == llvm::dwarf::DW_UT_skeleton)
41         cu_sp->m_dwo_id = debug_info.GetU64(offset_ptr);
42     } else {
43       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
44       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
45     }
46 
47     bool length_OK =
48         debug_info.ValidOffset(cu_sp->GetNextCompileUnitOffset() - 1);
49     bool version_OK = SymbolFileDWARF::SupportedVersion(cu_sp->m_version);
50     bool abbr_offset_OK =
51         dwarf2Data->get_debug_abbrev_data().ValidOffset(abbr_offset);
52     bool addr_size_OK = (cu_sp->m_addr_size == 4) || (cu_sp->m_addr_size == 8);
53 
54     if (length_OK && version_OK && addr_size_OK && abbr_offset_OK &&
55         abbr != NULL) {
56       cu_sp->m_abbrevs = abbr->GetAbbreviationDeclarationSet(abbr_offset);
57       return cu_sp;
58     }
59 
60     // reset the offset to where we tried to parse from if anything went wrong
61     *offset_ptr = cu_sp->m_offset;
62   }
63 
64   return nullptr;
65 }
66 
67 void DWARFCompileUnit::Dump(Stream *s) const {
68   s->Printf("0x%8.8x: Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
69             "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
70             "{0x%8.8x})\n",
71             m_offset, m_length, m_version, GetAbbrevOffset(), m_addr_size,
72             GetNextCompileUnitOffset());
73 }
74 
75 uint32_t DWARFCompileUnit::GetHeaderByteSize() const {
76   if (m_version < 5)
77     return m_is_dwarf64 ? 23 : 11;
78 
79   switch (m_unit_type) {
80   case llvm::dwarf::DW_UT_compile:
81   case llvm::dwarf::DW_UT_partial:
82     return 12;
83   case llvm::dwarf::DW_UT_skeleton:
84   case llvm::dwarf::DW_UT_split_compile:
85     return 20;
86   case llvm::dwarf::DW_UT_type:
87   case llvm::dwarf::DW_UT_split_type:
88     return 24;
89   }
90   llvm_unreachable("invalid UnitType.");
91 }
92 
93 const lldb_private::DWARFDataExtractor &DWARFCompileUnit::GetData() const {
94   return m_dwarf->get_debug_info_data();
95 }
96