1 //===-- DWARFDebugInfo.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 "SymbolFileDWARF.h"
10 
11 #include <algorithm>
12 #include <set>
13 
14 #include "lldb/Host/PosixApi.h"
15 #include "lldb/Symbol/ObjectFile.h"
16 #include "lldb/Utility/RegularExpression.h"
17 #include "lldb/Utility/Stream.h"
18 
19 #include "DWARFCompileUnit.h"
20 #include "DWARFContext.h"
21 #include "DWARFDebugAranges.h"
22 #include "DWARFDebugInfo.h"
23 #include "DWARFDebugInfoEntry.h"
24 #include "DWARFFormValue.h"
25 
26 using namespace lldb;
27 using namespace lldb_private;
28 using namespace std;
29 
30 // Constructor
31 DWARFDebugInfo::DWARFDebugInfo(lldb_private::DWARFContext &context)
32     : m_dwarf2Data(NULL), m_context(context), m_units(), m_cu_aranges_up() {}
33 
34 // SetDwarfData
35 void DWARFDebugInfo::SetDwarfData(SymbolFileDWARF *dwarf2Data) {
36   m_dwarf2Data = dwarf2Data;
37   m_units.clear();
38 }
39 
40 llvm::Expected<DWARFDebugAranges &> DWARFDebugInfo::GetCompileUnitAranges() {
41   if (m_cu_aranges_up)
42     return *m_cu_aranges_up;
43 
44   assert(m_dwarf2Data);
45 
46   m_cu_aranges_up = llvm::make_unique<DWARFDebugAranges>();
47   const DWARFDataExtractor &debug_aranges_data =
48       m_context.getOrLoadArangesData();
49   if (llvm::Error error = m_cu_aranges_up->extract(debug_aranges_data))
50     return std::move(error);
51 
52   // Make a list of all CUs represented by the arange data in the file.
53   std::set<dw_offset_t> cus_with_data;
54   for (size_t n = 0; n < m_cu_aranges_up->GetNumRanges(); n++) {
55     dw_offset_t offset = m_cu_aranges_up->OffsetAtIndex(n);
56     if (offset != DW_INVALID_OFFSET)
57       cus_with_data.insert(offset);
58   }
59 
60   // Manually build arange data for everything that wasn't in the
61   // .debug_aranges table.
62   const size_t num_units = GetNumUnits();
63   for (size_t idx = 0; idx < num_units; ++idx) {
64     DWARFUnit *cu = GetUnitAtIndex(idx);
65 
66     dw_offset_t offset = cu->GetOffset();
67     if (cus_with_data.find(offset) == cus_with_data.end())
68       cu->BuildAddressRangeTable(m_dwarf2Data, m_cu_aranges_up.get());
69   }
70 
71   const bool minimize = true;
72   m_cu_aranges_up->Sort(minimize);
73   return *m_cu_aranges_up;
74 }
75 
76 void DWARFDebugInfo::ParseUnitHeadersIfNeeded() {
77   if (!m_units.empty())
78     return;
79   if (!m_dwarf2Data)
80     return;
81 
82   lldb::offset_t offset = 0;
83   const auto &debug_info_data = m_context.getOrLoadDebugInfoData();
84   while (debug_info_data.ValidOffset(offset)) {
85     llvm::Expected<DWARFUnitSP> unit_sp = DWARFUnit::extract(
86         m_dwarf2Data, m_units.size(), debug_info_data, &offset);
87 
88     if (!unit_sp) {
89       // FIXME: Propagate this error up.
90       llvm::consumeError(unit_sp.takeError());
91       return;
92     }
93 
94     // If it didn't return an error, then it should be returning a valid Unit.
95     assert(*unit_sp);
96 
97     m_units.push_back(*unit_sp);
98 
99     offset = (*unit_sp)->GetNextUnitOffset();
100   }
101 }
102 
103 size_t DWARFDebugInfo::GetNumUnits() {
104   ParseUnitHeadersIfNeeded();
105   return m_units.size();
106 }
107 
108 DWARFUnit *DWARFDebugInfo::GetUnitAtIndex(user_id_t idx) {
109   DWARFUnit *cu = NULL;
110   if (idx < GetNumUnits())
111     cu = m_units[idx].get();
112   return cu;
113 }
114 
115 uint32_t DWARFDebugInfo::FindUnitIndex(DIERef::Section section,
116                                        dw_offset_t offset) {
117   ParseUnitHeadersIfNeeded();
118 
119   // llvm::lower_bound is not used as for DIE offsets it would still return
120   // index +1 and GetOffset() returning index itself would be a special case.
121   auto pos = llvm::upper_bound(
122       m_units, std::make_pair(section, offset),
123       [](const std::pair<DIERef::Section, dw_offset_t> &lhs,
124          const DWARFUnitSP &rhs) {
125         return lhs < std::make_pair(rhs->GetDebugSection(), rhs->GetOffset());
126       });
127   uint32_t idx = std::distance(m_units.begin(), pos);
128   if (idx == 0)
129     return DW_INVALID_OFFSET;
130   return idx - 1;
131 }
132 
133 DWARFUnit *DWARFDebugInfo::GetUnitAtOffset(DIERef::Section section,
134                                            dw_offset_t cu_offset,
135                                            uint32_t *idx_ptr) {
136   uint32_t idx = FindUnitIndex(section, cu_offset);
137   DWARFUnit *result = GetUnitAtIndex(idx);
138   if (result && result->GetOffset() != cu_offset) {
139     result = nullptr;
140     idx = DW_INVALID_INDEX;
141   }
142   if (idx_ptr)
143     *idx_ptr = idx;
144   return result;
145 }
146 
147 DWARFUnit *DWARFDebugInfo::GetUnit(const DIERef &die_ref) {
148   if (die_ref.cu_offset == DW_INVALID_OFFSET)
149     return GetUnitContainingDIEOffset(die_ref.section, die_ref.die_offset);
150   else
151     return GetUnitAtOffset(die_ref.section, die_ref.cu_offset);
152 }
153 
154 DWARFUnit *
155 DWARFDebugInfo::GetUnitContainingDIEOffset(DIERef::Section section,
156                                            dw_offset_t die_offset) {
157   uint32_t idx = FindUnitIndex(section, die_offset);
158   DWARFUnit *result = GetUnitAtIndex(idx);
159   if (result && !result->ContainsDIEOffset(die_offset))
160     return nullptr;
161   return result;
162 }
163 
164 DWARFDIE
165 DWARFDebugInfo::GetDIEForDIEOffset(DIERef::Section section,
166                                    dw_offset_t die_offset) {
167   DWARFUnit *cu = GetUnitContainingDIEOffset(section, die_offset);
168   if (cu)
169     return cu->GetDIE(die_offset);
170   return DWARFDIE();
171 }
172 
173 // GetDIE()
174 //
175 // Get the DIE (Debug Information Entry) with the specified offset.
176 DWARFDIE
177 DWARFDebugInfo::GetDIE(const DIERef &die_ref) {
178   DWARFUnit *cu = GetUnit(die_ref);
179   if (cu)
180     return cu->GetDIE(die_ref.die_offset);
181   return DWARFDIE(); // Not found
182 }
183 
184