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 extern int g_verbose;
18 
19 DWARFCompileUnit::DWARFCompileUnit(SymbolFileDWARF *dwarf2Data)
20     : DWARFUnit(dwarf2Data) {}
21 
22 DWARFUnitSP DWARFCompileUnit::Extract(SymbolFileDWARF *dwarf2Data,
23                                       const DWARFDataExtractor &debug_info,
24                                       lldb::offset_t *offset_ptr) {
25   // std::make_shared would require the ctor to be public.
26   std::shared_ptr<DWARFCompileUnit> cu_sp(new DWARFCompileUnit(dwarf2Data));
27 
28   cu_sp->m_offset = *offset_ptr;
29 
30   if (debug_info.ValidOffset(*offset_ptr)) {
31     dw_offset_t abbr_offset;
32     const DWARFDebugAbbrev *abbr = dwarf2Data->DebugAbbrev();
33     cu_sp->m_length = debug_info.GetDWARFInitialLength(offset_ptr);
34     cu_sp->m_is_dwarf64 = debug_info.IsDWARF64();
35     cu_sp->m_version = debug_info.GetU16(offset_ptr);
36 
37     if (cu_sp->m_version == 5) {
38       cu_sp->m_unit_type = debug_info.GetU8(offset_ptr);
39       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
40       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
41 
42       if (cu_sp->m_unit_type == llvm::dwarf::DW_UT_skeleton)
43         cu_sp->m_dwo_id = debug_info.GetU64(offset_ptr);
44     } else {
45       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
46       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
47     }
48 
49     bool length_OK =
50         debug_info.ValidOffset(cu_sp->GetNextCompileUnitOffset() - 1);
51     bool version_OK = SymbolFileDWARF::SupportedVersion(cu_sp->m_version);
52     bool abbr_offset_OK =
53         dwarf2Data->get_debug_abbrev_data().ValidOffset(abbr_offset);
54     bool addr_size_OK = (cu_sp->m_addr_size == 4) || (cu_sp->m_addr_size == 8);
55 
56     if (length_OK && version_OK && addr_size_OK && abbr_offset_OK &&
57         abbr != NULL) {
58       cu_sp->m_abbrevs = abbr->GetAbbreviationDeclarationSet(abbr_offset);
59       return cu_sp;
60     }
61 
62     // reset the offset to where we tried to parse from if anything went wrong
63     *offset_ptr = cu_sp->m_offset;
64   }
65 
66   return nullptr;
67 }
68 
69 void DWARFCompileUnit::Dump(Stream *s) const {
70   s->Printf("0x%8.8x: Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
71             "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
72             "{0x%8.8x})\n",
73             m_offset, m_length, m_version, GetAbbrevOffset(), m_addr_size,
74             GetNextCompileUnitOffset());
75 }
76 
77 uint32_t DWARFCompileUnit::GetHeaderByteSize() const {
78   if (m_version < 5)
79     return m_is_dwarf64 ? 23 : 11;
80 
81   switch (m_unit_type) {
82   case llvm::dwarf::DW_UT_compile:
83   case llvm::dwarf::DW_UT_partial:
84     return 12;
85   case llvm::dwarf::DW_UT_skeleton:
86   case llvm::dwarf::DW_UT_split_compile:
87     return 20;
88   case llvm::dwarf::DW_UT_type:
89   case llvm::dwarf::DW_UT_split_type:
90     return 24;
91   }
92   llvm_unreachable("invalid UnitType.");
93 }
94 
95 const lldb_private::DWARFDataExtractor &DWARFCompileUnit::GetData() const {
96   return m_dwarf->get_debug_info_data();
97 }
98