1 //===- DWARFUnitIndex.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 "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
10 #include "llvm/ADT/STLExtras.h"
11 #include "llvm/ADT/StringRef.h"
12 #include "llvm/Support/DataExtractor.h"
13 #include "llvm/Support/ErrorHandling.h"
14 #include "llvm/Support/Format.h"
15 #include "llvm/Support/raw_ostream.h"
16 #include <cinttypes>
17 #include <cstdint>
18
19 using namespace llvm;
20
21 namespace {
22
23 enum class DWARFSectionKindV2 {
24 DW_SECT_INFO = 1,
25 DW_SECT_TYPES = 2,
26 DW_SECT_ABBREV = 3,
27 DW_SECT_LINE = 4,
28 DW_SECT_LOC = 5,
29 DW_SECT_STR_OFFSETS = 6,
30 DW_SECT_MACINFO = 7,
31 DW_SECT_MACRO = 8,
32 };
33
34 } // namespace
35
36 // Return true if the section identifier is defined in the DWARFv5 standard.
isKnownV5SectionID(uint32_t ID)37 constexpr bool isKnownV5SectionID(uint32_t ID) {
38 return ID >= DW_SECT_INFO && ID <= DW_SECT_RNGLISTS &&
39 ID != DW_SECT_EXT_TYPES;
40 }
41
serializeSectionKind(DWARFSectionKind Kind,unsigned IndexVersion)42 uint32_t llvm::serializeSectionKind(DWARFSectionKind Kind,
43 unsigned IndexVersion) {
44 if (IndexVersion == 5) {
45 assert(isKnownV5SectionID(Kind));
46 return static_cast<uint32_t>(Kind);
47 }
48 assert(IndexVersion == 2);
49 switch (Kind) {
50 #define CASE(S,T) \
51 case DW_SECT_##S: \
52 return static_cast<uint32_t>(DWARFSectionKindV2::DW_SECT_##T)
53 CASE(INFO, INFO);
54 CASE(EXT_TYPES, TYPES);
55 CASE(ABBREV, ABBREV);
56 CASE(LINE, LINE);
57 CASE(EXT_LOC, LOC);
58 CASE(STR_OFFSETS, STR_OFFSETS);
59 CASE(EXT_MACINFO, MACINFO);
60 CASE(MACRO, MACRO);
61 #undef CASE
62 default:
63 // All other section kinds have no corresponding values in v2 indexes.
64 llvm_unreachable("Invalid DWARFSectionKind");
65 }
66 }
67
deserializeSectionKind(uint32_t Value,unsigned IndexVersion)68 DWARFSectionKind llvm::deserializeSectionKind(uint32_t Value,
69 unsigned IndexVersion) {
70 if (IndexVersion == 5)
71 return isKnownV5SectionID(Value)
72 ? static_cast<DWARFSectionKind>(Value)
73 : DW_SECT_EXT_unknown;
74 assert(IndexVersion == 2);
75 switch (static_cast<DWARFSectionKindV2>(Value)) {
76 #define CASE(S,T) \
77 case DWARFSectionKindV2::DW_SECT_##S: \
78 return DW_SECT_##T
79 CASE(INFO, INFO);
80 CASE(TYPES, EXT_TYPES);
81 CASE(ABBREV, ABBREV);
82 CASE(LINE, LINE);
83 CASE(LOC, EXT_LOC);
84 CASE(STR_OFFSETS, STR_OFFSETS);
85 CASE(MACINFO, EXT_MACINFO);
86 CASE(MACRO, MACRO);
87 #undef CASE
88 }
89 return DW_SECT_EXT_unknown;
90 }
91
parse(DataExtractor IndexData,uint64_t * OffsetPtr)92 bool DWARFUnitIndex::Header::parse(DataExtractor IndexData,
93 uint64_t *OffsetPtr) {
94 const uint64_t BeginOffset = *OffsetPtr;
95 if (!IndexData.isValidOffsetForDataOfSize(*OffsetPtr, 16))
96 return false;
97 // GCC Debug Fission defines the version as an unsigned 32-bit field
98 // with value of 2, https://gcc.gnu.org/wiki/DebugFissionDWP.
99 // DWARFv5 defines the same space as an uhalf version field with value of 5
100 // and a 2 bytes long padding, see Section 7.3.5.3.
101 Version = IndexData.getU32(OffsetPtr);
102 if (Version != 2) {
103 *OffsetPtr = BeginOffset;
104 Version = IndexData.getU16(OffsetPtr);
105 if (Version != 5)
106 return false;
107 *OffsetPtr += 2; // Skip padding.
108 }
109 NumColumns = IndexData.getU32(OffsetPtr);
110 NumUnits = IndexData.getU32(OffsetPtr);
111 NumBuckets = IndexData.getU32(OffsetPtr);
112 return true;
113 }
114
dump(raw_ostream & OS) const115 void DWARFUnitIndex::Header::dump(raw_ostream &OS) const {
116 OS << format("version = %u, units = %u, slots = %u\n\n", Version, NumUnits, NumBuckets);
117 }
118
parse(DataExtractor IndexData)119 bool DWARFUnitIndex::parse(DataExtractor IndexData) {
120 bool b = parseImpl(IndexData);
121 if (!b) {
122 // Make sure we don't try to dump anything
123 Header.NumBuckets = 0;
124 // Release any partially initialized data.
125 ColumnKinds.reset();
126 Rows.reset();
127 }
128 return b;
129 }
130
parseImpl(DataExtractor IndexData)131 bool DWARFUnitIndex::parseImpl(DataExtractor IndexData) {
132 uint64_t Offset = 0;
133 if (!Header.parse(IndexData, &Offset))
134 return false;
135
136 // Fix InfoColumnKind: in DWARFv5, type units are in .debug_info.dwo.
137 if (Header.Version == 5)
138 InfoColumnKind = DW_SECT_INFO;
139
140 if (!IndexData.isValidOffsetForDataOfSize(
141 Offset, Header.NumBuckets * (8 + 4) +
142 (2 * Header.NumUnits + 1) * 4 * Header.NumColumns))
143 return false;
144
145 Rows = std::make_unique<Entry[]>(Header.NumBuckets);
146 auto Contribs =
147 std::make_unique<Entry::SectionContribution *[]>(Header.NumUnits);
148 ColumnKinds = std::make_unique<DWARFSectionKind[]>(Header.NumColumns);
149 RawSectionIds = std::make_unique<uint32_t[]>(Header.NumColumns);
150
151 // Read Hash Table of Signatures
152 for (unsigned i = 0; i != Header.NumBuckets; ++i)
153 Rows[i].Signature = IndexData.getU64(&Offset);
154
155 // Read Parallel Table of Indexes
156 for (unsigned i = 0; i != Header.NumBuckets; ++i) {
157 auto Index = IndexData.getU32(&Offset);
158 if (!Index)
159 continue;
160 Rows[i].Index = this;
161 Rows[i].Contributions =
162 std::make_unique<Entry::SectionContribution[]>(Header.NumColumns);
163 Contribs[Index - 1] = Rows[i].Contributions.get();
164 }
165
166 // Read the Column Headers
167 for (unsigned i = 0; i != Header.NumColumns; ++i) {
168 RawSectionIds[i] = IndexData.getU32(&Offset);
169 ColumnKinds[i] = deserializeSectionKind(RawSectionIds[i], Header.Version);
170 if (ColumnKinds[i] == InfoColumnKind) {
171 if (InfoColumn != -1)
172 return false;
173 InfoColumn = i;
174 }
175 }
176
177 if (InfoColumn == -1)
178 return false;
179
180 // Read Table of Section Offsets
181 for (unsigned i = 0; i != Header.NumUnits; ++i) {
182 auto *Contrib = Contribs[i];
183 for (unsigned i = 0; i != Header.NumColumns; ++i)
184 Contrib[i].setOffset(IndexData.getU32(&Offset));
185 }
186
187 // Read Table of Section Sizes
188 for (unsigned i = 0; i != Header.NumUnits; ++i) {
189 auto *Contrib = Contribs[i];
190 for (unsigned i = 0; i != Header.NumColumns; ++i)
191 Contrib[i].setLength(IndexData.getU32(&Offset));
192 }
193
194 return true;
195 }
196
getColumnHeader(DWARFSectionKind DS)197 StringRef DWARFUnitIndex::getColumnHeader(DWARFSectionKind DS) {
198 switch (DS) {
199 #define HANDLE_DW_SECT(ID, NAME) \
200 case DW_SECT_##NAME: \
201 return #NAME;
202 #include "llvm/BinaryFormat/Dwarf.def"
203 case DW_SECT_EXT_TYPES:
204 return "TYPES";
205 case DW_SECT_EXT_LOC:
206 return "LOC";
207 case DW_SECT_EXT_MACINFO:
208 return "MACINFO";
209 case DW_SECT_EXT_unknown:
210 return StringRef();
211 }
212 llvm_unreachable("Unknown DWARFSectionKind");
213 }
214
dump(raw_ostream & OS) const215 void DWARFUnitIndex::dump(raw_ostream &OS) const {
216 if (!*this)
217 return;
218
219 Header.dump(OS);
220 OS << "Index Signature ";
221 for (unsigned i = 0; i != Header.NumColumns; ++i) {
222 DWARFSectionKind Kind = ColumnKinds[i];
223 StringRef Name = getColumnHeader(Kind);
224 if (!Name.empty())
225 OS << ' '
226 << left_justify(Name,
227 Kind == DWARFSectionKind::DW_SECT_INFO ? 40 : 24);
228 else
229 OS << format(" Unknown: %-15" PRIu32, RawSectionIds[i]);
230 }
231 OS << "\n----- ------------------";
232 for (unsigned i = 0; i != Header.NumColumns; ++i) {
233 DWARFSectionKind Kind = ColumnKinds[i];
234 if (Kind == DWARFSectionKind::DW_SECT_INFO ||
235 Kind == DWARFSectionKind::DW_SECT_EXT_TYPES)
236 OS << " ----------------------------------------";
237 else
238 OS << " ------------------------";
239 }
240 OS << '\n';
241 for (unsigned i = 0; i != Header.NumBuckets; ++i) {
242 auto &Row = Rows[i];
243 if (auto *Contribs = Row.Contributions.get()) {
244 OS << format("%5u 0x%016" PRIx64 " ", i + 1, Row.Signature);
245 for (unsigned i = 0; i != Header.NumColumns; ++i) {
246 auto &Contrib = Contribs[i];
247 DWARFSectionKind Kind = ColumnKinds[i];
248 if (Kind == DWARFSectionKind::DW_SECT_INFO ||
249 Kind == DWARFSectionKind::DW_SECT_EXT_TYPES)
250 OS << format("[0x%016" PRIx64 ", 0x%016" PRIx64 ") ",
251 Contrib.getOffset(),
252 Contrib.getOffset() + Contrib.getLength());
253 else
254 OS << format("[0x%08" PRIx32 ", 0x%08" PRIx32 ") ",
255 Contrib.getOffset32(),
256 Contrib.getOffset32() + Contrib.getLength32());
257 }
258 OS << '\n';
259 }
260 }
261 }
262
263 const DWARFUnitIndex::Entry::SectionContribution *
getContribution(DWARFSectionKind Sec) const264 DWARFUnitIndex::Entry::getContribution(DWARFSectionKind Sec) const {
265 uint32_t i = 0;
266 for (; i != Index->Header.NumColumns; ++i)
267 if (Index->ColumnKinds[i] == Sec)
268 return &Contributions[i];
269 return nullptr;
270 }
271
272 DWARFUnitIndex::Entry::SectionContribution &
getContribution()273 DWARFUnitIndex::Entry::getContribution() {
274 return Contributions[Index->InfoColumn];
275 }
276
277 const DWARFUnitIndex::Entry::SectionContribution *
getContribution() const278 DWARFUnitIndex::Entry::getContribution() const {
279 return &Contributions[Index->InfoColumn];
280 }
281
282 const DWARFUnitIndex::Entry *
getFromOffset(uint64_t Offset) const283 DWARFUnitIndex::getFromOffset(uint64_t Offset) const {
284 if (OffsetLookup.empty()) {
285 for (uint32_t i = 0; i != Header.NumBuckets; ++i)
286 if (Rows[i].Contributions)
287 OffsetLookup.push_back(&Rows[i]);
288 llvm::sort(OffsetLookup, [&](Entry *E1, Entry *E2) {
289 return E1->Contributions[InfoColumn].getOffset() <
290 E2->Contributions[InfoColumn].getOffset();
291 });
292 }
293 auto I = partition_point(OffsetLookup, [&](Entry *E2) {
294 return E2->Contributions[InfoColumn].getOffset() <= Offset;
295 });
296 if (I == OffsetLookup.begin())
297 return nullptr;
298 --I;
299 const auto *E = *I;
300 const auto &InfoContrib = E->Contributions[InfoColumn];
301 if ((InfoContrib.getOffset() + InfoContrib.getLength()) <= Offset)
302 return nullptr;
303 return E;
304 }
305
getFromHash(uint64_t S) const306 const DWARFUnitIndex::Entry *DWARFUnitIndex::getFromHash(uint64_t S) const {
307 uint64_t Mask = Header.NumBuckets - 1;
308
309 auto H = S & Mask;
310 auto HP = ((S >> 32) & Mask) | 1;
311 // The spec says "while 0 is a valid hash value, the row index in a used slot
312 // will always be non-zero". Loop until we find a match or an empty slot.
313 while (Rows[H].getSignature() != S && Rows[H].Index != nullptr)
314 H = (H + HP) & Mask;
315
316 // If the slot is empty, we don't care whether the signature matches (it could
317 // be zero and still match the zeros in the empty slot).
318 if (Rows[H].Index == nullptr)
319 return nullptr;
320
321 return &Rows[H];
322 }
323