1 //===-- DWARFDebugInfo.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 "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 #include "llvm/Support/Casting.h"
19 
20 #include "DWARFCompileUnit.h"
21 #include "DWARFContext.h"
22 #include "DWARFDebugAranges.h"
23 #include "DWARFDebugInfo.h"
24 #include "DWARFDebugInfoEntry.h"
25 #include "DWARFFormValue.h"
26 #include "DWARFTypeUnit.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 using namespace std;
31 
32 // Constructor
33 DWARFDebugInfo::DWARFDebugInfo(SymbolFileDWARF &dwarf,
34                                lldb_private::DWARFContext &context)
35     : m_dwarf(dwarf), m_context(context), m_units(), m_cu_aranges_up() {}
36 
37 const DWARFDebugAranges &DWARFDebugInfo::GetCompileUnitAranges() {
38   if (m_cu_aranges_up)
39     return *m_cu_aranges_up;
40 
41   m_cu_aranges_up = std::make_unique<DWARFDebugAranges>();
42   const DWARFDataExtractor &debug_aranges_data =
43       m_context.getOrLoadArangesData();
44 
45   // Extract what we can from the .debug_aranges first.
46   m_cu_aranges_up->extract(debug_aranges_data);
47 
48   // Make a list of all CUs represented by the .debug_aranges data.
49   std::set<dw_offset_t> cus_with_data;
50   for (size_t n = 0; n < m_cu_aranges_up->GetNumRanges(); n++) {
51     dw_offset_t offset = m_cu_aranges_up->OffsetAtIndex(n);
52     if (offset != DW_INVALID_OFFSET)
53       cus_with_data.insert(offset);
54   }
55 
56   // Manually build arange data for everything that wasn't in .debug_aranges.
57   const size_t num_units = GetNumUnits();
58   for (size_t idx = 0; idx < num_units; ++idx) {
59     DWARFUnit *cu = GetUnitAtIndex(idx);
60 
61     dw_offset_t offset = cu->GetOffset();
62     if (cus_with_data.find(offset) == cus_with_data.end())
63       cu->BuildAddressRangeTable(m_cu_aranges_up.get());
64   }
65 
66   const bool minimize = true;
67   m_cu_aranges_up->Sort(minimize);
68   return *m_cu_aranges_up;
69 }
70 
71 void DWARFDebugInfo::ParseUnitsFor(DIERef::Section section) {
72   DWARFDataExtractor data = section == DIERef::Section::DebugTypes
73                                 ? m_context.getOrLoadDebugTypesData()
74                                 : m_context.getOrLoadDebugInfoData();
75   lldb::offset_t offset = 0;
76   while (data.ValidOffset(offset)) {
77     llvm::Expected<DWARFUnitSP> unit_sp = DWARFUnit::extract(
78         m_dwarf, m_units.size(), data, section, &offset);
79 
80     if (!unit_sp) {
81       // FIXME: Propagate this error up.
82       llvm::consumeError(unit_sp.takeError());
83       return;
84     }
85 
86     // If it didn't return an error, then it should be returning a valid Unit.
87     assert(*unit_sp);
88     m_units.push_back(*unit_sp);
89     offset = (*unit_sp)->GetNextUnitOffset();
90 
91     if (auto *type_unit = llvm::dyn_cast<DWARFTypeUnit>(unit_sp->get())) {
92       m_type_hash_to_unit_index.emplace_back(type_unit->GetTypeHash(),
93                                              unit_sp.get()->GetID());
94     }
95   }
96 }
97 
98 void DWARFDebugInfo::ParseUnitHeadersIfNeeded() {
99   llvm::call_once(m_units_once_flag, [&] {
100     ParseUnitsFor(DIERef::Section::DebugInfo);
101     ParseUnitsFor(DIERef::Section::DebugTypes);
102     llvm::sort(m_type_hash_to_unit_index, llvm::less_first());
103   });
104 }
105 
106 size_t DWARFDebugInfo::GetNumUnits() {
107   ParseUnitHeadersIfNeeded();
108   return m_units.size();
109 }
110 
111 DWARFUnit *DWARFDebugInfo::GetUnitAtIndex(size_t idx) {
112   DWARFUnit *cu = nullptr;
113   if (idx < GetNumUnits())
114     cu = m_units[idx].get();
115   return cu;
116 }
117 
118 uint32_t DWARFDebugInfo::FindUnitIndex(DIERef::Section section,
119                                        dw_offset_t offset) {
120   ParseUnitHeadersIfNeeded();
121 
122   // llvm::lower_bound is not used as for DIE offsets it would still return
123   // index +1 and GetOffset() returning index itself would be a special case.
124   auto pos = llvm::upper_bound(
125       m_units, std::make_pair(section, offset),
126       [](const std::pair<DIERef::Section, dw_offset_t> &lhs,
127          const DWARFUnitSP &rhs) {
128         return lhs < std::make_pair(rhs->GetDebugSection(), rhs->GetOffset());
129       });
130   uint32_t idx = std::distance(m_units.begin(), pos);
131   if (idx == 0)
132     return DW_INVALID_OFFSET;
133   return idx - 1;
134 }
135 
136 DWARFUnit *DWARFDebugInfo::GetUnitAtOffset(DIERef::Section section,
137                                            dw_offset_t cu_offset,
138                                            uint32_t *idx_ptr) {
139   uint32_t idx = FindUnitIndex(section, cu_offset);
140   DWARFUnit *result = GetUnitAtIndex(idx);
141   if (result && result->GetOffset() != cu_offset) {
142     result = nullptr;
143     idx = DW_INVALID_INDEX;
144   }
145   if (idx_ptr)
146     *idx_ptr = idx;
147   return result;
148 }
149 
150 DWARFUnit *DWARFDebugInfo::GetUnit(const DIERef &die_ref) {
151   return GetUnitContainingDIEOffset(die_ref.section(), die_ref.die_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 DWARFTypeUnit *DWARFDebugInfo::GetTypeUnitForHash(uint64_t hash) {
165   auto pos = llvm::lower_bound(m_type_hash_to_unit_index,
166                                std::make_pair(hash, 0u), llvm::less_first());
167   if (pos == m_type_hash_to_unit_index.end() || pos->first != hash)
168     return nullptr;
169   return llvm::cast<DWARFTypeUnit>(GetUnitAtIndex(pos->second));
170 }
171 
172 bool DWARFDebugInfo::ContainsTypeUnits() {
173   ParseUnitHeadersIfNeeded();
174   return !m_type_hash_to_unit_index.empty();
175 }
176 
177 DWARFDIE
178 DWARFDebugInfo::GetDIEForDIEOffset(DIERef::Section section,
179                                    dw_offset_t die_offset) {
180   DWARFUnit *cu = GetUnitContainingDIEOffset(section, die_offset);
181   if (cu)
182     return cu->GetDIE(die_offset);
183   return DWARFDIE();
184 }
185 
186 // GetDIE()
187 //
188 // Get the DIE (Debug Information Entry) with the specified offset.
189 DWARFDIE
190 DWARFDebugInfo::GetDIE(const DIERef &die_ref) {
191   DWARFUnit *cu = GetUnit(die_ref);
192   if (cu)
193     return cu->GetNonSkeletonUnit().GetDIE(die_ref.die_offset());
194   return DWARFDIE(); // Not found
195 }
196