1 //===-- DWARFContext.cpp --------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/StringSwitch.h"
13 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
14 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
15 #include "llvm/Support/Compression.h"
16 #include "llvm/Support/Dwarf.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/Path.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include <algorithm>
21 using namespace llvm;
22 using namespace dwarf;
23 using namespace object;
24
25 #define DEBUG_TYPE "dwarf"
26
27 typedef DWARFDebugLine::LineTable DWARFLineTable;
28 typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind;
29 typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
30
dumpPubSection(raw_ostream & OS,StringRef Name,StringRef Data,bool LittleEndian,bool GnuStyle)31 static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data,
32 bool LittleEndian, bool GnuStyle) {
33 OS << "\n." << Name << " contents:\n";
34 DataExtractor pubNames(Data, LittleEndian, 0);
35 uint32_t offset = 0;
36 while (pubNames.isValidOffset(offset)) {
37 OS << "length = " << format("0x%08x", pubNames.getU32(&offset));
38 OS << " version = " << format("0x%04x", pubNames.getU16(&offset));
39 OS << " unit_offset = " << format("0x%08x", pubNames.getU32(&offset));
40 OS << " unit_size = " << format("0x%08x", pubNames.getU32(&offset)) << '\n';
41 if (GnuStyle)
42 OS << "Offset Linkage Kind Name\n";
43 else
44 OS << "Offset Name\n";
45
46 while (offset < Data.size()) {
47 uint32_t dieRef = pubNames.getU32(&offset);
48 if (dieRef == 0)
49 break;
50 OS << format("0x%8.8x ", dieRef);
51 if (GnuStyle) {
52 PubIndexEntryDescriptor desc(pubNames.getU8(&offset));
53 OS << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage))
54 << ' ' << format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind))
55 << ' ';
56 }
57 OS << '\"' << pubNames.getCStr(&offset) << "\"\n";
58 }
59 }
60 }
61
dumpAccelSection(raw_ostream & OS,StringRef Name,const DWARFSection & Section,StringRef StringSection,bool LittleEndian)62 static void dumpAccelSection(raw_ostream &OS, StringRef Name,
63 const DWARFSection& Section, StringRef StringSection,
64 bool LittleEndian) {
65 DataExtractor AccelSection(Section.Data, LittleEndian, 0);
66 DataExtractor StrData(StringSection, LittleEndian, 0);
67 OS << "\n." << Name << " contents:\n";
68 DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs);
69 if (!Accel.extract())
70 return;
71 Accel.dump(OS);
72 }
73
dump(raw_ostream & OS,DIDumpType DumpType)74 void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
75 if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
76 OS << ".debug_abbrev contents:\n";
77 getDebugAbbrev()->dump(OS);
78 }
79
80 if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo)
81 if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) {
82 OS << "\n.debug_abbrev.dwo contents:\n";
83 D->dump(OS);
84 }
85
86 if (DumpType == DIDT_All || DumpType == DIDT_Info) {
87 OS << "\n.debug_info contents:\n";
88 for (const auto &CU : compile_units())
89 CU->dump(OS);
90 }
91
92 if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) &&
93 getNumDWOCompileUnits()) {
94 OS << "\n.debug_info.dwo contents:\n";
95 for (const auto &DWOCU : dwo_compile_units())
96 DWOCU->dump(OS);
97 }
98
99 if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
100 OS << "\n.debug_types contents:\n";
101 for (const auto &TUS : type_unit_sections())
102 for (const auto &TU : TUS)
103 TU->dump(OS);
104 }
105
106 if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
107 getNumDWOTypeUnits()) {
108 OS << "\n.debug_types.dwo contents:\n";
109 for (const auto &DWOTUS : dwo_type_unit_sections())
110 for (const auto &DWOTU : DWOTUS)
111 DWOTU->dump(OS);
112 }
113
114 if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
115 OS << "\n.debug_loc contents:\n";
116 getDebugLoc()->dump(OS);
117 }
118
119 if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
120 OS << "\n.debug_loc.dwo contents:\n";
121 getDebugLocDWO()->dump(OS);
122 }
123
124 if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
125 OS << "\n.debug_frame contents:\n";
126 getDebugFrame()->dump(OS);
127 }
128
129 uint32_t offset = 0;
130 if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
131 OS << "\n.debug_aranges contents:\n";
132 DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
133 DWARFDebugArangeSet set;
134 while (set.extract(arangesData, &offset))
135 set.dump(OS);
136 }
137
138 uint8_t savedAddressByteSize = 0;
139 if (DumpType == DIDT_All || DumpType == DIDT_Line) {
140 OS << "\n.debug_line contents:\n";
141 for (const auto &CU : compile_units()) {
142 savedAddressByteSize = CU->getAddressByteSize();
143 const auto *CUDIE = CU->getUnitDIE();
144 if (CUDIE == nullptr)
145 continue;
146 unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
147 CU.get(), DW_AT_stmt_list, -1U);
148 if (stmtOffset != -1U) {
149 DataExtractor lineData(getLineSection().Data, isLittleEndian(),
150 savedAddressByteSize);
151 DWARFDebugLine::LineTable LineTable;
152 LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
153 LineTable.dump(OS);
154 }
155 }
156 }
157
158 if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
159 OS << "\n.debug_line.dwo contents:\n";
160 unsigned stmtOffset = 0;
161 DataExtractor lineData(getLineDWOSection().Data, isLittleEndian(),
162 savedAddressByteSize);
163 DWARFDebugLine::LineTable LineTable;
164 while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
165 LineTable.dump(OS);
166 LineTable.clear();
167 }
168 }
169
170 if (DumpType == DIDT_All || DumpType == DIDT_Str) {
171 OS << "\n.debug_str contents:\n";
172 DataExtractor strData(getStringSection(), isLittleEndian(), 0);
173 offset = 0;
174 uint32_t strOffset = 0;
175 while (const char *s = strData.getCStr(&offset)) {
176 OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
177 strOffset = offset;
178 }
179 }
180
181 if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
182 !getStringDWOSection().empty()) {
183 OS << "\n.debug_str.dwo contents:\n";
184 DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
185 offset = 0;
186 uint32_t strDWOOffset = 0;
187 while (const char *s = strDWOData.getCStr(&offset)) {
188 OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
189 strDWOOffset = offset;
190 }
191 }
192
193 if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
194 OS << "\n.debug_ranges contents:\n";
195 // In fact, different compile units may have different address byte
196 // sizes, but for simplicity we just use the address byte size of the last
197 // compile unit (there is no easy and fast way to associate address range
198 // list and the compile unit it describes).
199 DataExtractor rangesData(getRangeSection(), isLittleEndian(),
200 savedAddressByteSize);
201 offset = 0;
202 DWARFDebugRangeList rangeList;
203 while (rangeList.extract(rangesData, &offset))
204 rangeList.dump(OS);
205 }
206
207 if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
208 dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
209 isLittleEndian(), false);
210
211 if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
212 dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
213 isLittleEndian(), false);
214
215 if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
216 dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
217 isLittleEndian(), true /* GnuStyle */);
218
219 if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
220 dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
221 isLittleEndian(), true /* GnuStyle */);
222
223 if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) &&
224 !getStringOffsetDWOSection().empty()) {
225 OS << "\n.debug_str_offsets.dwo contents:\n";
226 DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(),
227 0);
228 offset = 0;
229 uint64_t size = getStringOffsetDWOSection().size();
230 while (offset < size) {
231 OS << format("0x%8.8x: ", offset);
232 OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
233 }
234 }
235
236 if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
237 dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
238 getStringSection(), isLittleEndian());
239
240 if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
241 dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
242 getStringSection(), isLittleEndian());
243
244 if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
245 dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
246 getStringSection(), isLittleEndian());
247
248 if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
249 dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
250 getStringSection(), isLittleEndian());
251 }
252
getDebugAbbrev()253 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
254 if (Abbrev)
255 return Abbrev.get();
256
257 DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
258
259 Abbrev.reset(new DWARFDebugAbbrev());
260 Abbrev->extract(abbrData);
261 return Abbrev.get();
262 }
263
getDebugAbbrevDWO()264 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
265 if (AbbrevDWO)
266 return AbbrevDWO.get();
267
268 DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
269 AbbrevDWO.reset(new DWARFDebugAbbrev());
270 AbbrevDWO->extract(abbrData);
271 return AbbrevDWO.get();
272 }
273
getDebugLoc()274 const DWARFDebugLoc *DWARFContext::getDebugLoc() {
275 if (Loc)
276 return Loc.get();
277
278 DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
279 Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
280 // assume all compile units have the same address byte size
281 if (getNumCompileUnits())
282 Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
283 return Loc.get();
284 }
285
getDebugLocDWO()286 const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
287 if (LocDWO)
288 return LocDWO.get();
289
290 DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0);
291 LocDWO.reset(new DWARFDebugLocDWO());
292 LocDWO->parse(LocData);
293 return LocDWO.get();
294 }
295
getDebugAranges()296 const DWARFDebugAranges *DWARFContext::getDebugAranges() {
297 if (Aranges)
298 return Aranges.get();
299
300 Aranges.reset(new DWARFDebugAranges());
301 Aranges->generate(this);
302 return Aranges.get();
303 }
304
getDebugFrame()305 const DWARFDebugFrame *DWARFContext::getDebugFrame() {
306 if (DebugFrame)
307 return DebugFrame.get();
308
309 // There's a "bug" in the DWARFv3 standard with respect to the target address
310 // size within debug frame sections. While DWARF is supposed to be independent
311 // of its container, FDEs have fields with size being "target address size",
312 // which isn't specified in DWARF in general. It's only specified for CUs, but
313 // .eh_frame can appear without a .debug_info section. Follow the example of
314 // other tools (libdwarf) and extract this from the container (ObjectFile
315 // provides this information). This problem is fixed in DWARFv4
316 // See this dwarf-discuss discussion for more details:
317 // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
318 DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
319 getAddressSize());
320 DebugFrame.reset(new DWARFDebugFrame());
321 DebugFrame->parse(debugFrameData);
322 return DebugFrame.get();
323 }
324
325 const DWARFLineTable *
getLineTableForUnit(DWARFUnit * U)326 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
327 if (!Line)
328 Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
329 const auto *UnitDIE = U->getUnitDIE();
330 if (UnitDIE == nullptr)
331 return nullptr;
332 unsigned stmtOffset =
333 UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
334 if (stmtOffset == -1U)
335 return nullptr; // No line table for this compile unit.
336
337 // See if the line table is cached.
338 if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
339 return lt;
340
341 // We have to parse it first.
342 DataExtractor lineData(getLineSection().Data, isLittleEndian(),
343 U->getAddressByteSize());
344 return Line->getOrParseLineTable(lineData, stmtOffset);
345 }
346
parseCompileUnits()347 void DWARFContext::parseCompileUnits() {
348 CUs.parse(*this, getInfoSection());
349 }
350
parseTypeUnits()351 void DWARFContext::parseTypeUnits() {
352 if (!TUs.empty())
353 return;
354 for (const auto &I : getTypesSections()) {
355 TUs.emplace_back();
356 TUs.back().parse(*this, I.second);
357 }
358 }
359
parseDWOCompileUnits()360 void DWARFContext::parseDWOCompileUnits() {
361 DWOCUs.parseDWO(*this, getInfoDWOSection());
362 }
363
parseDWOTypeUnits()364 void DWARFContext::parseDWOTypeUnits() {
365 if (!DWOTUs.empty())
366 return;
367 for (const auto &I : getTypesDWOSections()) {
368 DWOTUs.emplace_back();
369 DWOTUs.back().parseDWO(*this, I.second);
370 }
371 }
372
getCompileUnitForOffset(uint32_t Offset)373 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
374 parseCompileUnits();
375 return CUs.getUnitForOffset(Offset);
376 }
377
getCompileUnitForAddress(uint64_t Address)378 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
379 // First, get the offset of the compile unit.
380 uint32_t CUOffset = getDebugAranges()->findAddress(Address);
381 // Retrieve the compile unit.
382 return getCompileUnitForOffset(CUOffset);
383 }
384
getFunctionNameForAddress(DWARFCompileUnit * CU,uint64_t Address,FunctionNameKind Kind,std::string & FunctionName)385 static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
386 FunctionNameKind Kind,
387 std::string &FunctionName) {
388 if (Kind == FunctionNameKind::None)
389 return false;
390 // The address may correspond to instruction in some inlined function,
391 // so we have to build the chain of inlined functions and take the
392 // name of the topmost function in it.
393 const DWARFDebugInfoEntryInlinedChain &InlinedChain =
394 CU->getInlinedChainForAddress(Address);
395 if (InlinedChain.DIEs.size() == 0)
396 return false;
397 const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
398 if (const char *Name =
399 TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
400 FunctionName = Name;
401 return true;
402 }
403 return false;
404 }
405
getLineInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)406 DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
407 DILineInfoSpecifier Spec) {
408 DILineInfo Result;
409
410 DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
411 if (!CU)
412 return Result;
413 getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
414 if (Spec.FLIKind != FileLineInfoKind::None) {
415 if (const DWARFLineTable *LineTable = getLineTableForUnit(CU))
416 LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
417 Spec.FLIKind, Result);
418 }
419 return Result;
420 }
421
422 DILineInfoTable
getLineInfoForAddressRange(uint64_t Address,uint64_t Size,DILineInfoSpecifier Spec)423 DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
424 DILineInfoSpecifier Spec) {
425 DILineInfoTable Lines;
426 DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
427 if (!CU)
428 return Lines;
429
430 std::string FunctionName = "<invalid>";
431 getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName);
432
433 // If the Specifier says we don't need FileLineInfo, just
434 // return the top-most function at the starting address.
435 if (Spec.FLIKind == FileLineInfoKind::None) {
436 DILineInfo Result;
437 Result.FunctionName = FunctionName;
438 Lines.push_back(std::make_pair(Address, Result));
439 return Lines;
440 }
441
442 const DWARFLineTable *LineTable = getLineTableForUnit(CU);
443
444 // Get the index of row we're looking for in the line table.
445 std::vector<uint32_t> RowVector;
446 if (!LineTable->lookupAddressRange(Address, Size, RowVector))
447 return Lines;
448
449 for (uint32_t RowIndex : RowVector) {
450 // Take file number and line/column from the row.
451 const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
452 DILineInfo Result;
453 LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
454 Spec.FLIKind, Result.FileName);
455 Result.FunctionName = FunctionName;
456 Result.Line = Row.Line;
457 Result.Column = Row.Column;
458 Lines.push_back(std::make_pair(Row.Address, Result));
459 }
460
461 return Lines;
462 }
463
464 DIInliningInfo
getInliningInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)465 DWARFContext::getInliningInfoForAddress(uint64_t Address,
466 DILineInfoSpecifier Spec) {
467 DIInliningInfo InliningInfo;
468
469 DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
470 if (!CU)
471 return InliningInfo;
472
473 const DWARFLineTable *LineTable = nullptr;
474 const DWARFDebugInfoEntryInlinedChain &InlinedChain =
475 CU->getInlinedChainForAddress(Address);
476 if (InlinedChain.DIEs.size() == 0) {
477 // If there is no DIE for address (e.g. it is in unavailable .dwo file),
478 // try to at least get file/line info from symbol table.
479 if (Spec.FLIKind != FileLineInfoKind::None) {
480 DILineInfo Frame;
481 LineTable = getLineTableForUnit(CU);
482 if (LineTable &&
483 LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
484 Spec.FLIKind, Frame))
485 InliningInfo.addFrame(Frame);
486 }
487 return InliningInfo;
488 }
489
490 uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
491 for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
492 const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
493 DILineInfo Frame;
494 // Get function name if necessary.
495 if (const char *Name =
496 FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
497 Frame.FunctionName = Name;
498 if (Spec.FLIKind != FileLineInfoKind::None) {
499 if (i == 0) {
500 // For the topmost frame, initialize the line table of this
501 // compile unit and fetch file/line info from it.
502 LineTable = getLineTableForUnit(CU);
503 // For the topmost routine, get file/line info from line table.
504 if (LineTable)
505 LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
506 Spec.FLIKind, Frame);
507 } else {
508 // Otherwise, use call file, call line and call column from
509 // previous DIE in inlined chain.
510 if (LineTable)
511 LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
512 Spec.FLIKind, Frame.FileName);
513 Frame.Line = CallLine;
514 Frame.Column = CallColumn;
515 }
516 // Get call file/line/column of a current DIE.
517 if (i + 1 < n) {
518 FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
519 CallColumn);
520 }
521 }
522 InliningInfo.addFrame(Frame);
523 }
524 return InliningInfo;
525 }
526
consumeCompressedDebugSectionHeader(StringRef & data,uint64_t & OriginalSize)527 static bool consumeCompressedDebugSectionHeader(StringRef &data,
528 uint64_t &OriginalSize) {
529 // Consume "ZLIB" prefix.
530 if (!data.startswith("ZLIB"))
531 return false;
532 data = data.substr(4);
533 // Consume uncompressed section size (big-endian 8 bytes).
534 DataExtractor extractor(data, false, 8);
535 uint32_t Offset = 0;
536 OriginalSize = extractor.getU64(&Offset);
537 if (Offset == 0)
538 return false;
539 data = data.substr(Offset);
540 return true;
541 }
542
DWARFContextInMemory(const object::ObjectFile & Obj,const LoadedObjectInfo * L)543 DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
544 const LoadedObjectInfo *L)
545 : IsLittleEndian(Obj.isLittleEndian()),
546 AddressSize(Obj.getBytesInAddress()) {
547 for (const SectionRef &Section : Obj.sections()) {
548 StringRef name;
549 Section.getName(name);
550 // Skip BSS and Virtual sections, they aren't interesting.
551 bool IsBSS = Section.isBSS();
552 if (IsBSS)
553 continue;
554 bool IsVirtual = Section.isVirtual();
555 if (IsVirtual)
556 continue;
557 StringRef data;
558
559 // Try to obtain an already relocated version of this section.
560 // Else use the unrelocated section from the object file. We'll have to
561 // apply relocations ourselves later.
562 if (!L || !L->getLoadedSectionContents(name,data))
563 Section.getContents(data);
564
565 name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
566
567 // Check if debug info section is compressed with zlib.
568 if (name.startswith("zdebug_")) {
569 uint64_t OriginalSize;
570 if (!zlib::isAvailable() ||
571 !consumeCompressedDebugSectionHeader(data, OriginalSize))
572 continue;
573 UncompressedSections.resize(UncompressedSections.size() + 1);
574 if (zlib::uncompress(data, UncompressedSections.back(), OriginalSize) !=
575 zlib::StatusOK) {
576 UncompressedSections.pop_back();
577 continue;
578 }
579 // Make data point to uncompressed section contents and save its contents.
580 name = name.substr(1);
581 data = UncompressedSections.back();
582 }
583
584 StringRef *SectionData =
585 StringSwitch<StringRef *>(name)
586 .Case("debug_info", &InfoSection.Data)
587 .Case("debug_abbrev", &AbbrevSection)
588 .Case("debug_loc", &LocSection.Data)
589 .Case("debug_line", &LineSection.Data)
590 .Case("debug_aranges", &ARangeSection)
591 .Case("debug_frame", &DebugFrameSection)
592 .Case("debug_str", &StringSection)
593 .Case("debug_ranges", &RangeSection)
594 .Case("debug_pubnames", &PubNamesSection)
595 .Case("debug_pubtypes", &PubTypesSection)
596 .Case("debug_gnu_pubnames", &GnuPubNamesSection)
597 .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
598 .Case("debug_info.dwo", &InfoDWOSection.Data)
599 .Case("debug_abbrev.dwo", &AbbrevDWOSection)
600 .Case("debug_loc.dwo", &LocDWOSection.Data)
601 .Case("debug_line.dwo", &LineDWOSection.Data)
602 .Case("debug_str.dwo", &StringDWOSection)
603 .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
604 .Case("debug_addr", &AddrSection)
605 .Case("apple_names", &AppleNamesSection.Data)
606 .Case("apple_types", &AppleTypesSection.Data)
607 .Case("apple_namespaces", &AppleNamespacesSection.Data)
608 .Case("apple_namespac", &AppleNamespacesSection.Data)
609 .Case("apple_objc", &AppleObjCSection.Data)
610 // Any more debug info sections go here.
611 .Default(nullptr);
612 if (SectionData) {
613 *SectionData = data;
614 if (name == "debug_ranges") {
615 // FIXME: Use the other dwo range section when we emit it.
616 RangeDWOSection = data;
617 }
618 } else if (name == "debug_types") {
619 // Find debug_types data by section rather than name as there are
620 // multiple, comdat grouped, debug_types sections.
621 TypesSections[Section].Data = data;
622 } else if (name == "debug_types.dwo") {
623 TypesDWOSections[Section].Data = data;
624 }
625
626 section_iterator RelocatedSection = Section.getRelocatedSection();
627 if (RelocatedSection == Obj.section_end())
628 continue;
629
630 StringRef RelSecName;
631 StringRef RelSecData;
632 RelocatedSection->getName(RelSecName);
633
634 // If the section we're relocating was relocated already by the JIT,
635 // then we used the relocated version above, so we do not need to process
636 // relocations for it now.
637 if (L && L->getLoadedSectionContents(RelSecName,RelSecData))
638 continue;
639
640 RelSecName = RelSecName.substr(
641 RelSecName.find_first_not_of("._")); // Skip . and _ prefixes.
642
643 // TODO: Add support for relocations in other sections as needed.
644 // Record relocations for the debug_info and debug_line sections.
645 RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
646 .Case("debug_info", &InfoSection.Relocs)
647 .Case("debug_loc", &LocSection.Relocs)
648 .Case("debug_info.dwo", &InfoDWOSection.Relocs)
649 .Case("debug_line", &LineSection.Relocs)
650 .Case("apple_names", &AppleNamesSection.Relocs)
651 .Case("apple_types", &AppleTypesSection.Relocs)
652 .Case("apple_namespaces", &AppleNamespacesSection.Relocs)
653 .Case("apple_namespac", &AppleNamespacesSection.Relocs)
654 .Case("apple_objc", &AppleObjCSection.Relocs)
655 .Default(nullptr);
656 if (!Map) {
657 // Find debug_types relocs by section rather than name as there are
658 // multiple, comdat grouped, debug_types sections.
659 if (RelSecName == "debug_types")
660 Map = &TypesSections[*RelocatedSection].Relocs;
661 else if (RelSecName == "debug_types.dwo")
662 Map = &TypesDWOSections[*RelocatedSection].Relocs;
663 else
664 continue;
665 }
666
667 if (Section.relocation_begin() != Section.relocation_end()) {
668 uint64_t SectionSize = RelocatedSection->getSize();
669 for (const RelocationRef &Reloc : Section.relocations()) {
670 uint64_t Address = Reloc.getOffset();
671 uint64_t Type = Reloc.getType();
672 uint64_t SymAddr = 0;
673 uint64_t SectionLoadAddress = 0;
674 object::symbol_iterator Sym = Reloc.getSymbol();
675 object::section_iterator RSec = Obj.section_end();
676
677 // First calculate the address of the symbol or section as it appears
678 // in the objct file
679 if (Sym != Obj.symbol_end()) {
680 ErrorOr<uint64_t> SymAddrOrErr = Sym->getAddress();
681 if (std::error_code EC = SymAddrOrErr.getError()) {
682 errs() << "error: failed to compute symbol address: "
683 << EC.message() << '\n';
684 continue;
685 }
686 SymAddr = *SymAddrOrErr;
687 // Also remember what section this symbol is in for later
688 Sym->getSection(RSec);
689 } else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
690 // MachO also has relocations that point to sections and
691 // scattered relocations.
692 // FIXME: We are not handling scattered relocations, do we have to?
693 RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
694 SymAddr = RSec->getAddress();
695 }
696
697 // If we are given load addresses for the sections, we need to adjust:
698 // SymAddr = (Address of Symbol Or Section in File) -
699 // (Address of Section in File) +
700 // (Load Address of Section)
701 if (L != nullptr && RSec != Obj.section_end()) {
702 // RSec is now either the section being targetted or the section
703 // containing the symbol being targetted. In either case,
704 // we need to perform the same computation.
705 StringRef SecName;
706 RSec->getName(SecName);
707 SectionLoadAddress = L->getSectionLoadAddress(SecName);
708 if (SectionLoadAddress != 0)
709 SymAddr += SectionLoadAddress - RSec->getAddress();
710 }
711
712 object::RelocVisitor V(Obj);
713 object::RelocToApply R(V.visit(Type, Reloc, SymAddr));
714 if (V.error()) {
715 SmallString<32> Name;
716 Reloc.getTypeName(Name);
717 errs() << "error: failed to compute relocation: "
718 << Name << "\n";
719 continue;
720 }
721
722 if (Address + R.Width > SectionSize) {
723 errs() << "error: " << R.Width << "-byte relocation starting "
724 << Address << " bytes into section " << name << " which is "
725 << SectionSize << " bytes long.\n";
726 continue;
727 }
728 if (R.Width > 8) {
729 errs() << "error: can't handle a relocation of more than 8 bytes at "
730 "a time.\n";
731 continue;
732 }
733 DEBUG(dbgs() << "Writing " << format("%p", R.Value)
734 << " at " << format("%p", Address)
735 << " with width " << format("%d", R.Width)
736 << "\n");
737 Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
738 }
739 }
740 }
741 }
742
anchor()743 void DWARFContextInMemory::anchor() { }
744