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 #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 llvm::Expected<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   if (llvm::Error error = m_cu_aranges_up->extract(debug_aranges_data))
45     return std::move(error);
46 
47   // Make a list of all CUs represented by the arange data in the file.
48   std::set<dw_offset_t> cus_with_data;
49   for (size_t n = 0; n < m_cu_aranges_up->GetNumRanges(); n++) {
50     dw_offset_t offset = m_cu_aranges_up->OffsetAtIndex(n);
51     if (offset != DW_INVALID_OFFSET)
52       cus_with_data.insert(offset);
53   }
54 
55   // Manually build arange data for everything that wasn't in the
56   // .debug_aranges table.
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 =
78         DWARFUnit::extract(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   if (!m_units.empty())
100     return;
101 
102   ParseUnitsFor(DIERef::Section::DebugInfo);
103   ParseUnitsFor(DIERef::Section::DebugTypes);
104   llvm::sort(m_type_hash_to_unit_index, llvm::less_first());
105 }
106 
107 size_t DWARFDebugInfo::GetNumUnits() {
108   ParseUnitHeadersIfNeeded();
109   return m_units.size();
110 }
111 
112 DWARFUnit *DWARFDebugInfo::GetUnitAtIndex(user_id_t idx) {
113   DWARFUnit *cu = nullptr;
114   if (idx < GetNumUnits())
115     cu = m_units[idx].get();
116   return cu;
117 }
118 
119 uint32_t DWARFDebugInfo::FindUnitIndex(DIERef::Section section,
120                                        dw_offset_t offset) {
121   ParseUnitHeadersIfNeeded();
122 
123   // llvm::lower_bound is not used as for DIE offsets it would still return
124   // index +1 and GetOffset() returning index itself would be a special case.
125   auto pos = llvm::upper_bound(
126       m_units, std::make_pair(section, offset),
127       [](const std::pair<DIERef::Section, dw_offset_t> &lhs,
128          const DWARFUnitSP &rhs) {
129         return lhs < std::make_pair(rhs->GetDebugSection(), rhs->GetOffset());
130       });
131   uint32_t idx = std::distance(m_units.begin(), pos);
132   if (idx == 0)
133     return DW_INVALID_OFFSET;
134   return idx - 1;
135 }
136 
137 DWARFUnit *DWARFDebugInfo::GetUnitAtOffset(DIERef::Section section,
138                                            dw_offset_t cu_offset,
139                                            uint32_t *idx_ptr) {
140   uint32_t idx = FindUnitIndex(section, cu_offset);
141   DWARFUnit *result = GetUnitAtIndex(idx);
142   if (result && result->GetOffset() != cu_offset) {
143     result = nullptr;
144     idx = DW_INVALID_INDEX;
145   }
146   if (idx_ptr)
147     *idx_ptr = idx;
148   return result;
149 }
150 
151 DWARFUnit *DWARFDebugInfo::GetUnit(const DIERef &die_ref) {
152   return GetUnitContainingDIEOffset(die_ref.section(), die_ref.die_offset());
153 }
154 
155 DWARFUnit *
156 DWARFDebugInfo::GetUnitContainingDIEOffset(DIERef::Section section,
157                                            dw_offset_t die_offset) {
158   uint32_t idx = FindUnitIndex(section, die_offset);
159   DWARFUnit *result = GetUnitAtIndex(idx);
160   if (result && !result->ContainsDIEOffset(die_offset))
161     return nullptr;
162   return result;
163 }
164 
165 DWARFTypeUnit *DWARFDebugInfo::GetTypeUnitForHash(uint64_t hash) {
166   auto pos = llvm::lower_bound(m_type_hash_to_unit_index,
167                                std::make_pair(hash, 0u), llvm::less_first());
168   if (pos == m_type_hash_to_unit_index.end() || pos->first != hash)
169     return nullptr;
170   return llvm::cast<DWARFTypeUnit>(GetUnitAtIndex(pos->second));
171 }
172 
173 bool DWARFDebugInfo::ContainsTypeUnits() {
174   ParseUnitHeadersIfNeeded();
175   return !m_type_hash_to_unit_index.empty();
176 }
177 
178 DWARFDIE
179 DWARFDebugInfo::GetDIEForDIEOffset(DIERef::Section section,
180                                    dw_offset_t die_offset) {
181   DWARFUnit *cu = GetUnitContainingDIEOffset(section, die_offset);
182   if (cu)
183     return cu->GetDIE(die_offset);
184   return DWARFDIE();
185 }
186 
187 // GetDIE()
188 //
189 // Get the DIE (Debug Information Entry) with the specified offset.
190 DWARFDIE
191 DWARFDebugInfo::GetDIE(const DIERef &die_ref) {
192   DWARFUnit *cu = GetUnit(die_ref);
193   if (cu)
194     return cu->GetDIE(die_ref.die_offset());
195   return DWARFDIE(); // Not found
196 }
197 
198