1 //===- DWARFDebugLoc.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/DWARFDebugLoc.h"
10 #include "llvm/ADT/StringRef.h"
11 #include "llvm/BinaryFormat/Dwarf.h"
12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
13 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
14 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
15 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
16 #include "llvm/Support/Compiler.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/WithColor.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include <algorithm>
21 #include <cinttypes>
22 #include <cstdint>
23
24 using namespace llvm;
25 using object::SectionedAddress;
26
27 namespace {
28 class DWARFLocationInterpreter {
29 Optional<object::SectionedAddress> Base;
30 std::function<Optional<object::SectionedAddress>(uint32_t)> LookupAddr;
31
32 public:
DWARFLocationInterpreter(Optional<object::SectionedAddress> Base,std::function<Optional<object::SectionedAddress> (uint32_t)> LookupAddr)33 DWARFLocationInterpreter(
34 Optional<object::SectionedAddress> Base,
35 std::function<Optional<object::SectionedAddress>(uint32_t)> LookupAddr)
36 : Base(Base), LookupAddr(std::move(LookupAddr)) {}
37
38 Expected<Optional<DWARFLocationExpression>>
39 Interpret(const DWARFLocationEntry &E);
40 };
41 } // namespace
42
createResolverError(uint32_t Index,unsigned Kind)43 static Error createResolverError(uint32_t Index, unsigned Kind) {
44 return createStringError(errc::invalid_argument,
45 "Unable to resolve indirect address %u for: %s",
46 Index, dwarf::LocListEncodingString(Kind).data());
47 }
48
49 Expected<Optional<DWARFLocationExpression>>
Interpret(const DWARFLocationEntry & E)50 DWARFLocationInterpreter::Interpret(const DWARFLocationEntry &E) {
51 switch (E.Kind) {
52 case dwarf::DW_LLE_end_of_list:
53 return None;
54 case dwarf::DW_LLE_base_addressx: {
55 Base = LookupAddr(E.Value0);
56 if (!Base)
57 return createResolverError(E.Value0, E.Kind);
58 return None;
59 }
60 case dwarf::DW_LLE_startx_endx: {
61 Optional<SectionedAddress> LowPC = LookupAddr(E.Value0);
62 if (!LowPC)
63 return createResolverError(E.Value0, E.Kind);
64 Optional<SectionedAddress> HighPC = LookupAddr(E.Value1);
65 if (!HighPC)
66 return createResolverError(E.Value1, E.Kind);
67 return DWARFLocationExpression{
68 DWARFAddressRange{LowPC->Address, HighPC->Address, LowPC->SectionIndex},
69 E.Loc};
70 }
71 case dwarf::DW_LLE_startx_length: {
72 Optional<SectionedAddress> LowPC = LookupAddr(E.Value0);
73 if (!LowPC)
74 return createResolverError(E.Value0, E.Kind);
75 return DWARFLocationExpression{DWARFAddressRange{LowPC->Address,
76 LowPC->Address + E.Value1,
77 LowPC->SectionIndex},
78 E.Loc};
79 }
80 case dwarf::DW_LLE_offset_pair: {
81 if (!Base) {
82 return createStringError(inconvertibleErrorCode(),
83 "Unable to resolve location list offset pair: "
84 "Base address not defined");
85 }
86 DWARFAddressRange Range{Base->Address + E.Value0, Base->Address + E.Value1,
87 Base->SectionIndex};
88 if (Range.SectionIndex == SectionedAddress::UndefSection)
89 Range.SectionIndex = E.SectionIndex;
90 return DWARFLocationExpression{Range, E.Loc};
91 }
92 case dwarf::DW_LLE_default_location:
93 return DWARFLocationExpression{None, E.Loc};
94 case dwarf::DW_LLE_base_address:
95 Base = SectionedAddress{E.Value0, E.SectionIndex};
96 return None;
97 case dwarf::DW_LLE_start_end:
98 return DWARFLocationExpression{
99 DWARFAddressRange{E.Value0, E.Value1, E.SectionIndex}, E.Loc};
100 case dwarf::DW_LLE_start_length:
101 return DWARFLocationExpression{
102 DWARFAddressRange{E.Value0, E.Value0 + E.Value1, E.SectionIndex},
103 E.Loc};
104 default:
105 llvm_unreachable("unreachable locations list kind");
106 }
107 }
108
dumpExpression(raw_ostream & OS,ArrayRef<uint8_t> Data,bool IsLittleEndian,unsigned AddressSize,const MCRegisterInfo * MRI,DWARFUnit * U)109 static void dumpExpression(raw_ostream &OS, ArrayRef<uint8_t> Data,
110 bool IsLittleEndian, unsigned AddressSize,
111 const MCRegisterInfo *MRI, DWARFUnit *U) {
112 DWARFDataExtractor Extractor(Data, IsLittleEndian, AddressSize);
113 // Note. We do not pass any format to DWARFExpression, even if the
114 // corresponding unit is known. For now, there is only one operation,
115 // DW_OP_call_ref, which depends on the format; it is rarely used, and
116 // is unexpected in location tables.
117 DWARFExpression(Extractor, AddressSize).print(OS, MRI, U);
118 }
119
dumpLocationList(uint64_t * Offset,raw_ostream & OS,Optional<SectionedAddress> BaseAddr,const MCRegisterInfo * MRI,const DWARFObject & Obj,DWARFUnit * U,DIDumpOptions DumpOpts,unsigned Indent) const120 bool DWARFLocationTable::dumpLocationList(uint64_t *Offset, raw_ostream &OS,
121 Optional<SectionedAddress> BaseAddr,
122 const MCRegisterInfo *MRI,
123 const DWARFObject &Obj, DWARFUnit *U,
124 DIDumpOptions DumpOpts,
125 unsigned Indent) const {
126 DWARFLocationInterpreter Interp(
127 BaseAddr, [U](uint32_t Index) -> Optional<SectionedAddress> {
128 if (U)
129 return U->getAddrOffsetSectionItem(Index);
130 return None;
131 });
132 OS << format("0x%8.8" PRIx64 ": ", *Offset);
133 Error E = visitLocationList(Offset, [&](const DWARFLocationEntry &E) {
134 Expected<Optional<DWARFLocationExpression>> Loc = Interp.Interpret(E);
135 if (!Loc || DumpOpts.DisplayRawContents)
136 dumpRawEntry(E, OS, Indent, DumpOpts, Obj);
137 if (Loc && *Loc) {
138 OS << "\n";
139 OS.indent(Indent);
140 if (DumpOpts.DisplayRawContents)
141 OS << " => ";
142
143 DIDumpOptions RangeDumpOpts(DumpOpts);
144 RangeDumpOpts.DisplayRawContents = false;
145 if (Loc.get()->Range)
146 Loc.get()->Range->dump(OS, Data.getAddressSize(), RangeDumpOpts, &Obj);
147 else
148 OS << "<default>";
149 }
150 if (!Loc)
151 consumeError(Loc.takeError());
152
153 if (E.Kind != dwarf::DW_LLE_base_address &&
154 E.Kind != dwarf::DW_LLE_base_addressx &&
155 E.Kind != dwarf::DW_LLE_end_of_list) {
156 OS << ": ";
157 dumpExpression(OS, E.Loc, Data.isLittleEndian(), Data.getAddressSize(),
158 MRI, U);
159 }
160 return true;
161 });
162 if (E) {
163 DumpOpts.RecoverableErrorHandler(std::move(E));
164 return false;
165 }
166 return true;
167 }
168
visitAbsoluteLocationList(uint64_t Offset,Optional<SectionedAddress> BaseAddr,std::function<Optional<SectionedAddress> (uint32_t)> LookupAddr,function_ref<bool (Expected<DWARFLocationExpression>)> Callback) const169 Error DWARFLocationTable::visitAbsoluteLocationList(
170 uint64_t Offset, Optional<SectionedAddress> BaseAddr,
171 std::function<Optional<SectionedAddress>(uint32_t)> LookupAddr,
172 function_ref<bool(Expected<DWARFLocationExpression>)> Callback) const {
173 DWARFLocationInterpreter Interp(BaseAddr, std::move(LookupAddr));
174 return visitLocationList(&Offset, [&](const DWARFLocationEntry &E) {
175 Expected<Optional<DWARFLocationExpression>> Loc = Interp.Interpret(E);
176 if (!Loc)
177 return Callback(Loc.takeError());
178 if (*Loc)
179 return Callback(**Loc);
180 return true;
181 });
182 }
183
dump(raw_ostream & OS,const MCRegisterInfo * MRI,const DWARFObject & Obj,DIDumpOptions DumpOpts,Optional<uint64_t> DumpOffset) const184 void DWARFDebugLoc::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
185 const DWARFObject &Obj, DIDumpOptions DumpOpts,
186 Optional<uint64_t> DumpOffset) const {
187 auto BaseAddr = None;
188 unsigned Indent = 12;
189 if (DumpOffset) {
190 dumpLocationList(&*DumpOffset, OS, BaseAddr, MRI, Obj, nullptr, DumpOpts,
191 Indent);
192 } else {
193 uint64_t Offset = 0;
194 StringRef Separator;
195 bool CanContinue = true;
196 while (CanContinue && Data.isValidOffset(Offset)) {
197 OS << Separator;
198 Separator = "\n";
199
200 CanContinue = dumpLocationList(&Offset, OS, BaseAddr, MRI, Obj, nullptr,
201 DumpOpts, Indent);
202 OS << '\n';
203 }
204 }
205 }
206
visitLocationList(uint64_t * Offset,function_ref<bool (const DWARFLocationEntry &)> Callback) const207 Error DWARFDebugLoc::visitLocationList(
208 uint64_t *Offset,
209 function_ref<bool(const DWARFLocationEntry &)> Callback) const {
210 DataExtractor::Cursor C(*Offset);
211 while (true) {
212 uint64_t SectionIndex;
213 uint64_t Value0 = Data.getRelocatedAddress(C);
214 uint64_t Value1 = Data.getRelocatedAddress(C, &SectionIndex);
215
216 DWARFLocationEntry E;
217
218 // The end of any given location list is marked by an end of list entry,
219 // which consists of a 0 for the beginning address offset and a 0 for the
220 // ending address offset. A beginning offset of 0xff...f marks the base
221 // address selection entry.
222 if (Value0 == 0 && Value1 == 0) {
223 E.Kind = dwarf::DW_LLE_end_of_list;
224 } else if (Value0 == (Data.getAddressSize() == 4 ? -1U : -1ULL)) {
225 E.Kind = dwarf::DW_LLE_base_address;
226 E.Value0 = Value1;
227 E.SectionIndex = SectionIndex;
228 } else {
229 E.Kind = dwarf::DW_LLE_offset_pair;
230 E.Value0 = Value0;
231 E.Value1 = Value1;
232 E.SectionIndex = SectionIndex;
233 unsigned Bytes = Data.getU16(C);
234 // A single location description describing the location of the object...
235 Data.getU8(C, E.Loc, Bytes);
236 }
237
238 if (!C)
239 return C.takeError();
240 if (!Callback(E) || E.Kind == dwarf::DW_LLE_end_of_list)
241 break;
242 }
243 *Offset = C.tell();
244 return Error::success();
245 }
246
dumpRawEntry(const DWARFLocationEntry & Entry,raw_ostream & OS,unsigned Indent,DIDumpOptions DumpOpts,const DWARFObject & Obj) const247 void DWARFDebugLoc::dumpRawEntry(const DWARFLocationEntry &Entry,
248 raw_ostream &OS, unsigned Indent,
249 DIDumpOptions DumpOpts,
250 const DWARFObject &Obj) const {
251 uint64_t Value0, Value1;
252 switch (Entry.Kind) {
253 case dwarf::DW_LLE_base_address:
254 Value0 = Data.getAddressSize() == 4 ? -1U : -1ULL;
255 Value1 = Entry.Value0;
256 break;
257 case dwarf::DW_LLE_offset_pair:
258 Value0 = Entry.Value0;
259 Value1 = Entry.Value1;
260 break;
261 case dwarf::DW_LLE_end_of_list:
262 Value0 = Value1 = 0;
263 return;
264 default:
265 llvm_unreachable("Not possible in DWARF4!");
266 }
267 OS << '\n';
268 OS.indent(Indent);
269 OS << '(' << format_hex(Value0, 2 + Data.getAddressSize() * 2) << ", "
270 << format_hex(Value1, 2 + Data.getAddressSize() * 2) << ')';
271 DWARFFormValue::dumpAddressSection(Obj, OS, DumpOpts, Entry.SectionIndex);
272 }
273
visitLocationList(uint64_t * Offset,function_ref<bool (const DWARFLocationEntry &)> F) const274 Error DWARFDebugLoclists::visitLocationList(
275 uint64_t *Offset, function_ref<bool(const DWARFLocationEntry &)> F) const {
276
277 DataExtractor::Cursor C(*Offset);
278 bool Continue = true;
279 while (Continue) {
280 DWARFLocationEntry E;
281 E.Kind = Data.getU8(C);
282 switch (E.Kind) {
283 case dwarf::DW_LLE_end_of_list:
284 break;
285 case dwarf::DW_LLE_base_addressx:
286 E.Value0 = Data.getULEB128(C);
287 break;
288 case dwarf::DW_LLE_startx_endx:
289 E.Value0 = Data.getULEB128(C);
290 E.Value1 = Data.getULEB128(C);
291 break;
292 case dwarf::DW_LLE_startx_length:
293 E.Value0 = Data.getULEB128(C);
294 // Pre-DWARF 5 has different interpretation of the length field. We have
295 // to support both pre- and standartized styles for the compatibility.
296 if (Version < 5)
297 E.Value1 = Data.getU32(C);
298 else
299 E.Value1 = Data.getULEB128(C);
300 break;
301 case dwarf::DW_LLE_offset_pair:
302 E.Value0 = Data.getULEB128(C);
303 E.Value1 = Data.getULEB128(C);
304 E.SectionIndex = SectionedAddress::UndefSection;
305 break;
306 case dwarf::DW_LLE_default_location:
307 break;
308 case dwarf::DW_LLE_base_address:
309 E.Value0 = Data.getRelocatedAddress(C, &E.SectionIndex);
310 break;
311 case dwarf::DW_LLE_start_end:
312 E.Value0 = Data.getRelocatedAddress(C, &E.SectionIndex);
313 E.Value1 = Data.getRelocatedAddress(C);
314 break;
315 case dwarf::DW_LLE_start_length:
316 E.Value0 = Data.getRelocatedAddress(C, &E.SectionIndex);
317 E.Value1 = Data.getULEB128(C);
318 break;
319 default:
320 cantFail(C.takeError());
321 return createStringError(errc::illegal_byte_sequence,
322 "LLE of kind %x not supported", (int)E.Kind);
323 }
324
325 if (E.Kind != dwarf::DW_LLE_base_address &&
326 E.Kind != dwarf::DW_LLE_base_addressx &&
327 E.Kind != dwarf::DW_LLE_end_of_list) {
328 unsigned Bytes = Version >= 5 ? Data.getULEB128(C) : Data.getU16(C);
329 // A single location description describing the location of the object...
330 Data.getU8(C, E.Loc, Bytes);
331 }
332
333 if (!C)
334 return C.takeError();
335 Continue = F(E) && E.Kind != dwarf::DW_LLE_end_of_list;
336 }
337 *Offset = C.tell();
338 return Error::success();
339 }
340
dumpRawEntry(const DWARFLocationEntry & Entry,raw_ostream & OS,unsigned Indent,DIDumpOptions DumpOpts,const DWARFObject & Obj) const341 void DWARFDebugLoclists::dumpRawEntry(const DWARFLocationEntry &Entry,
342 raw_ostream &OS, unsigned Indent,
343 DIDumpOptions DumpOpts,
344 const DWARFObject &Obj) const {
345 size_t MaxEncodingStringLength = 0;
346 #define HANDLE_DW_LLE(ID, NAME) \
347 MaxEncodingStringLength = std::max(MaxEncodingStringLength, \
348 dwarf::LocListEncodingString(ID).size());
349 #include "llvm/BinaryFormat/Dwarf.def"
350
351 OS << "\n";
352 OS.indent(Indent);
353 StringRef EncodingString = dwarf::LocListEncodingString(Entry.Kind);
354 // Unsupported encodings should have been reported during parsing.
355 assert(!EncodingString.empty() && "Unknown loclist entry encoding");
356 OS << format("%-*s(", MaxEncodingStringLength, EncodingString.data());
357 unsigned FieldSize = 2 + 2 * Data.getAddressSize();
358 switch (Entry.Kind) {
359 case dwarf::DW_LLE_end_of_list:
360 case dwarf::DW_LLE_default_location:
361 break;
362 case dwarf::DW_LLE_startx_endx:
363 case dwarf::DW_LLE_startx_length:
364 case dwarf::DW_LLE_offset_pair:
365 case dwarf::DW_LLE_start_end:
366 case dwarf::DW_LLE_start_length:
367 OS << format_hex(Entry.Value0, FieldSize) << ", "
368 << format_hex(Entry.Value1, FieldSize);
369 break;
370 case dwarf::DW_LLE_base_addressx:
371 case dwarf::DW_LLE_base_address:
372 OS << format_hex(Entry.Value0, FieldSize);
373 break;
374 }
375 OS << ')';
376 switch (Entry.Kind) {
377 case dwarf::DW_LLE_base_address:
378 case dwarf::DW_LLE_start_end:
379 case dwarf::DW_LLE_start_length:
380 DWARFFormValue::dumpAddressSection(Obj, OS, DumpOpts, Entry.SectionIndex);
381 break;
382 default:
383 break;
384 }
385 }
386
dumpRange(uint64_t StartOffset,uint64_t Size,raw_ostream & OS,const MCRegisterInfo * MRI,const DWARFObject & Obj,DIDumpOptions DumpOpts)387 void DWARFDebugLoclists::dumpRange(uint64_t StartOffset, uint64_t Size,
388 raw_ostream &OS, const MCRegisterInfo *MRI,
389 const DWARFObject &Obj,
390 DIDumpOptions DumpOpts) {
391 if (!Data.isValidOffsetForDataOfSize(StartOffset, Size)) {
392 OS << "Invalid dump range\n";
393 return;
394 }
395 uint64_t Offset = StartOffset;
396 StringRef Separator;
397 bool CanContinue = true;
398 while (CanContinue && Offset < StartOffset + Size) {
399 OS << Separator;
400 Separator = "\n";
401
402 CanContinue = dumpLocationList(&Offset, OS, /*BaseAddr=*/None, MRI, Obj,
403 nullptr, DumpOpts, /*Indent=*/12);
404 OS << '\n';
405 }
406 }
407