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