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/DebugInfo/DWARF/DWARFUnitIndex.h"
16 #include "llvm/Support/Compression.h"
17 #include "llvm/Support/Dwarf.h"
18 #include "llvm/Support/Format.h"
19 #include "llvm/Support/Path.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include <algorithm>
22 using namespace llvm;
23 using namespace dwarf;
24 using namespace object;
25 
26 #define DEBUG_TYPE "dwarf"
27 
28 typedef DWARFDebugLine::LineTable DWARFLineTable;
29 typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind;
30 typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
31 
dumpPubSection(raw_ostream & OS,StringRef Name,StringRef Data,bool LittleEndian,bool GnuStyle)32 static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data,
33                            bool LittleEndian, bool GnuStyle) {
34   OS << "\n." << Name << " contents:\n";
35   DataExtractor pubNames(Data, LittleEndian, 0);
36   uint32_t offset = 0;
37   while (pubNames.isValidOffset(offset)) {
38     OS << "length = " << format("0x%08x", pubNames.getU32(&offset));
39     OS << " version = " << format("0x%04x", pubNames.getU16(&offset));
40     OS << " unit_offset = " << format("0x%08x", pubNames.getU32(&offset));
41     OS << " unit_size = " << format("0x%08x", pubNames.getU32(&offset)) << '\n';
42     if (GnuStyle)
43       OS << "Offset     Linkage  Kind     Name\n";
44     else
45       OS << "Offset     Name\n";
46 
47     while (offset < Data.size()) {
48       uint32_t dieRef = pubNames.getU32(&offset);
49       if (dieRef == 0)
50         break;
51       OS << format("0x%8.8x ", dieRef);
52       if (GnuStyle) {
53         PubIndexEntryDescriptor desc(pubNames.getU8(&offset));
54         OS << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage))
55            << ' ' << format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind))
56            << ' ';
57       }
58       OS << '\"' << pubNames.getCStr(&offset) << "\"\n";
59     }
60   }
61 }
62 
dumpAccelSection(raw_ostream & OS,StringRef Name,const DWARFSection & Section,StringRef StringSection,bool LittleEndian)63 static void dumpAccelSection(raw_ostream &OS, StringRef Name,
64                              const DWARFSection& Section, StringRef StringSection,
65                              bool LittleEndian) {
66   DataExtractor AccelSection(Section.Data, LittleEndian, 0);
67   DataExtractor StrData(StringSection, LittleEndian, 0);
68   OS << "\n." << Name << " contents:\n";
69   DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs);
70   if (!Accel.extract())
71     return;
72   Accel.dump(OS);
73 }
74 
dump(raw_ostream & OS,DIDumpType DumpType)75 void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
76   if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
77     OS << ".debug_abbrev contents:\n";
78     getDebugAbbrev()->dump(OS);
79   }
80 
81   if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo)
82     if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) {
83       OS << "\n.debug_abbrev.dwo contents:\n";
84       D->dump(OS);
85     }
86 
87   if (DumpType == DIDT_All || DumpType == DIDT_Info) {
88     OS << "\n.debug_info contents:\n";
89     for (const auto &CU : compile_units())
90       CU->dump(OS);
91   }
92 
93   if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) &&
94       getNumDWOCompileUnits()) {
95     OS << "\n.debug_info.dwo contents:\n";
96     for (const auto &DWOCU : dwo_compile_units())
97       DWOCU->dump(OS);
98   }
99 
100   if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
101     OS << "\n.debug_types contents:\n";
102     for (const auto &TUS : type_unit_sections())
103       for (const auto &TU : TUS)
104         TU->dump(OS);
105   }
106 
107   if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
108       getNumDWOTypeUnits()) {
109     OS << "\n.debug_types.dwo contents:\n";
110     for (const auto &DWOTUS : dwo_type_unit_sections())
111       for (const auto &DWOTU : DWOTUS)
112         DWOTU->dump(OS);
113   }
114 
115   if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
116     OS << "\n.debug_loc contents:\n";
117     getDebugLoc()->dump(OS);
118   }
119 
120   if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
121     OS << "\n.debug_loc.dwo contents:\n";
122     getDebugLocDWO()->dump(OS);
123   }
124 
125   if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
126     OS << "\n.debug_frame contents:\n";
127     getDebugFrame()->dump(OS);
128   }
129 
130   if (DumpType == DIDT_All || DumpType == DIDT_Macro) {
131     OS << "\n.debug_macinfo contents:\n";
132     getDebugMacro()->dump(OS);
133   }
134 
135   uint32_t offset = 0;
136   if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
137     OS << "\n.debug_aranges contents:\n";
138     DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
139     DWARFDebugArangeSet set;
140     while (set.extract(arangesData, &offset))
141       set.dump(OS);
142   }
143 
144   uint8_t savedAddressByteSize = 0;
145   if (DumpType == DIDT_All || DumpType == DIDT_Line) {
146     OS << "\n.debug_line contents:\n";
147     for (const auto &CU : compile_units()) {
148       savedAddressByteSize = CU->getAddressByteSize();
149       const auto *CUDIE = CU->getUnitDIE();
150       if (CUDIE == nullptr)
151         continue;
152       unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
153           CU.get(), DW_AT_stmt_list, -1U);
154       if (stmtOffset != -1U) {
155         DataExtractor lineData(getLineSection().Data, isLittleEndian(),
156                                savedAddressByteSize);
157         DWARFDebugLine::LineTable LineTable;
158         LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
159         LineTable.dump(OS);
160       }
161     }
162   }
163 
164   if (DumpType == DIDT_All || DumpType == DIDT_CUIndex) {
165     OS << "\n.debug_cu_index contents:\n";
166     getCUIndex().dump(OS);
167   }
168 
169   if (DumpType == DIDT_All || DumpType == DIDT_TUIndex) {
170     OS << "\n.debug_tu_index contents:\n";
171     getTUIndex().dump(OS);
172   }
173 
174   if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
175     OS << "\n.debug_line.dwo contents:\n";
176     unsigned stmtOffset = 0;
177     DataExtractor lineData(getLineDWOSection().Data, isLittleEndian(),
178                            savedAddressByteSize);
179     DWARFDebugLine::LineTable LineTable;
180     while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
181       LineTable.dump(OS);
182       LineTable.clear();
183     }
184   }
185 
186   if (DumpType == DIDT_All || DumpType == DIDT_Str) {
187     OS << "\n.debug_str contents:\n";
188     DataExtractor strData(getStringSection(), isLittleEndian(), 0);
189     offset = 0;
190     uint32_t strOffset = 0;
191     while (const char *s = strData.getCStr(&offset)) {
192       OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
193       strOffset = offset;
194     }
195   }
196 
197   if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
198       !getStringDWOSection().empty()) {
199     OS << "\n.debug_str.dwo contents:\n";
200     DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
201     offset = 0;
202     uint32_t strDWOOffset = 0;
203     while (const char *s = strDWOData.getCStr(&offset)) {
204       OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
205       strDWOOffset = offset;
206     }
207   }
208 
209   if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
210     OS << "\n.debug_ranges contents:\n";
211     // In fact, different compile units may have different address byte
212     // sizes, but for simplicity we just use the address byte size of the last
213     // compile unit (there is no easy and fast way to associate address range
214     // list and the compile unit it describes).
215     DataExtractor rangesData(getRangeSection(), isLittleEndian(),
216                              savedAddressByteSize);
217     offset = 0;
218     DWARFDebugRangeList rangeList;
219     while (rangeList.extract(rangesData, &offset))
220       rangeList.dump(OS);
221   }
222 
223   if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
224     dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
225                    isLittleEndian(), false);
226 
227   if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
228     dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
229                    isLittleEndian(), false);
230 
231   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
232     dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
233                    isLittleEndian(), true /* GnuStyle */);
234 
235   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
236     dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
237                    isLittleEndian(), true /* GnuStyle */);
238 
239   if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) &&
240       !getStringOffsetDWOSection().empty()) {
241     OS << "\n.debug_str_offsets.dwo contents:\n";
242     DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(),
243                                0);
244     offset = 0;
245     uint64_t size = getStringOffsetDWOSection().size();
246     while (offset < size) {
247       OS << format("0x%8.8x: ", offset);
248       OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
249     }
250   }
251 
252   if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
253     dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
254                      getStringSection(), isLittleEndian());
255 
256   if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
257     dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
258                      getStringSection(), isLittleEndian());
259 
260   if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
261     dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
262                      getStringSection(), isLittleEndian());
263 
264   if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
265     dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
266                      getStringSection(), isLittleEndian());
267 }
268 
getCUIndex()269 const DWARFUnitIndex &DWARFContext::getCUIndex() {
270   if (CUIndex)
271     return *CUIndex;
272 
273   DataExtractor CUIndexData(getCUIndexSection(), isLittleEndian(), 0);
274 
275   CUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_INFO);
276   CUIndex->parse(CUIndexData);
277   return *CUIndex;
278 }
279 
getTUIndex()280 const DWARFUnitIndex &DWARFContext::getTUIndex() {
281   if (TUIndex)
282     return *TUIndex;
283 
284   DataExtractor TUIndexData(getTUIndexSection(), isLittleEndian(), 0);
285 
286   TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES);
287   TUIndex->parse(TUIndexData);
288   return *TUIndex;
289 }
290 
getDebugAbbrev()291 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
292   if (Abbrev)
293     return Abbrev.get();
294 
295   DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
296 
297   Abbrev.reset(new DWARFDebugAbbrev());
298   Abbrev->extract(abbrData);
299   return Abbrev.get();
300 }
301 
getDebugAbbrevDWO()302 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
303   if (AbbrevDWO)
304     return AbbrevDWO.get();
305 
306   DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
307   AbbrevDWO.reset(new DWARFDebugAbbrev());
308   AbbrevDWO->extract(abbrData);
309   return AbbrevDWO.get();
310 }
311 
getDebugLoc()312 const DWARFDebugLoc *DWARFContext::getDebugLoc() {
313   if (Loc)
314     return Loc.get();
315 
316   DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
317   Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
318   // assume all compile units have the same address byte size
319   if (getNumCompileUnits())
320     Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
321   return Loc.get();
322 }
323 
getDebugLocDWO()324 const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
325   if (LocDWO)
326     return LocDWO.get();
327 
328   DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0);
329   LocDWO.reset(new DWARFDebugLocDWO());
330   LocDWO->parse(LocData);
331   return LocDWO.get();
332 }
333 
getDebugAranges()334 const DWARFDebugAranges *DWARFContext::getDebugAranges() {
335   if (Aranges)
336     return Aranges.get();
337 
338   Aranges.reset(new DWARFDebugAranges());
339   Aranges->generate(this);
340   return Aranges.get();
341 }
342 
getDebugFrame()343 const DWARFDebugFrame *DWARFContext::getDebugFrame() {
344   if (DebugFrame)
345     return DebugFrame.get();
346 
347   // There's a "bug" in the DWARFv3 standard with respect to the target address
348   // size within debug frame sections. While DWARF is supposed to be independent
349   // of its container, FDEs have fields with size being "target address size",
350   // which isn't specified in DWARF in general. It's only specified for CUs, but
351   // .eh_frame can appear without a .debug_info section. Follow the example of
352   // other tools (libdwarf) and extract this from the container (ObjectFile
353   // provides this information). This problem is fixed in DWARFv4
354   // See this dwarf-discuss discussion for more details:
355   // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
356   DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
357                                getAddressSize());
358   DebugFrame.reset(new DWARFDebugFrame());
359   DebugFrame->parse(debugFrameData);
360   return DebugFrame.get();
361 }
362 
getDebugMacro()363 const DWARFDebugMacro *DWARFContext::getDebugMacro() {
364   if (Macro)
365     return Macro.get();
366 
367   DataExtractor MacinfoData(getMacinfoSection(), isLittleEndian(), 0);
368   Macro.reset(new DWARFDebugMacro());
369   Macro->parse(MacinfoData);
370   return Macro.get();
371 }
372 
373 const DWARFLineTable *
getLineTableForUnit(DWARFUnit * U)374 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
375   if (!Line)
376     Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
377 
378   const auto *UnitDIE = U->getUnitDIE();
379   if (UnitDIE == nullptr)
380     return nullptr;
381 
382   unsigned stmtOffset =
383       UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
384   if (stmtOffset == -1U)
385     return nullptr; // No line table for this compile unit.
386 
387   stmtOffset += U->getLineTableOffset();
388   // See if the line table is cached.
389   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
390     return lt;
391 
392   // We have to parse it first.
393   DataExtractor lineData(U->getLineSection(), isLittleEndian(),
394                          U->getAddressByteSize());
395   return Line->getOrParseLineTable(lineData, stmtOffset);
396 }
397 
parseCompileUnits()398 void DWARFContext::parseCompileUnits() {
399   CUs.parse(*this, getInfoSection());
400 }
401 
parseTypeUnits()402 void DWARFContext::parseTypeUnits() {
403   if (!TUs.empty())
404     return;
405   for (const auto &I : getTypesSections()) {
406     TUs.emplace_back();
407     TUs.back().parse(*this, I.second);
408   }
409 }
410 
parseDWOCompileUnits()411 void DWARFContext::parseDWOCompileUnits() {
412   DWOCUs.parseDWO(*this, getInfoDWOSection());
413 }
414 
parseDWOTypeUnits()415 void DWARFContext::parseDWOTypeUnits() {
416   if (!DWOTUs.empty())
417     return;
418   for (const auto &I : getTypesDWOSections()) {
419     DWOTUs.emplace_back();
420     DWOTUs.back().parseDWO(*this, I.second);
421   }
422 }
423 
getCompileUnitForOffset(uint32_t Offset)424 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
425   parseCompileUnits();
426   return CUs.getUnitForOffset(Offset);
427 }
428 
getCompileUnitForAddress(uint64_t Address)429 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
430   // First, get the offset of the compile unit.
431   uint32_t CUOffset = getDebugAranges()->findAddress(Address);
432   // Retrieve the compile unit.
433   return getCompileUnitForOffset(CUOffset);
434 }
435 
getFunctionNameForAddress(DWARFCompileUnit * CU,uint64_t Address,FunctionNameKind Kind,std::string & FunctionName)436 static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
437                                       FunctionNameKind Kind,
438                                       std::string &FunctionName) {
439   if (Kind == FunctionNameKind::None)
440     return false;
441   // The address may correspond to instruction in some inlined function,
442   // so we have to build the chain of inlined functions and take the
443   // name of the topmost function in it.
444   const DWARFDebugInfoEntryInlinedChain &InlinedChain =
445       CU->getInlinedChainForAddress(Address);
446   if (InlinedChain.DIEs.size() == 0)
447     return false;
448   const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
449   if (const char *Name =
450           TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
451     FunctionName = Name;
452     return true;
453   }
454   return false;
455 }
456 
getLineInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)457 DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
458                                                DILineInfoSpecifier Spec) {
459   DILineInfo Result;
460 
461   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
462   if (!CU)
463     return Result;
464   getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
465   if (Spec.FLIKind != FileLineInfoKind::None) {
466     if (const DWARFLineTable *LineTable = getLineTableForUnit(CU))
467       LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
468                                            Spec.FLIKind, Result);
469   }
470   return Result;
471 }
472 
473 DILineInfoTable
getLineInfoForAddressRange(uint64_t Address,uint64_t Size,DILineInfoSpecifier Spec)474 DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
475                                          DILineInfoSpecifier Spec) {
476   DILineInfoTable  Lines;
477   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
478   if (!CU)
479     return Lines;
480 
481   std::string FunctionName = "<invalid>";
482   getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName);
483 
484   // If the Specifier says we don't need FileLineInfo, just
485   // return the top-most function at the starting address.
486   if (Spec.FLIKind == FileLineInfoKind::None) {
487     DILineInfo Result;
488     Result.FunctionName = FunctionName;
489     Lines.push_back(std::make_pair(Address, Result));
490     return Lines;
491   }
492 
493   const DWARFLineTable *LineTable = getLineTableForUnit(CU);
494 
495   // Get the index of row we're looking for in the line table.
496   std::vector<uint32_t> RowVector;
497   if (!LineTable->lookupAddressRange(Address, Size, RowVector))
498     return Lines;
499 
500   for (uint32_t RowIndex : RowVector) {
501     // Take file number and line/column from the row.
502     const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
503     DILineInfo Result;
504     LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
505                                   Spec.FLIKind, Result.FileName);
506     Result.FunctionName = FunctionName;
507     Result.Line = Row.Line;
508     Result.Column = Row.Column;
509     Lines.push_back(std::make_pair(Row.Address, Result));
510   }
511 
512   return Lines;
513 }
514 
515 DIInliningInfo
getInliningInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)516 DWARFContext::getInliningInfoForAddress(uint64_t Address,
517                                         DILineInfoSpecifier Spec) {
518   DIInliningInfo InliningInfo;
519 
520   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
521   if (!CU)
522     return InliningInfo;
523 
524   const DWARFLineTable *LineTable = nullptr;
525   const DWARFDebugInfoEntryInlinedChain &InlinedChain =
526       CU->getInlinedChainForAddress(Address);
527   if (InlinedChain.DIEs.size() == 0) {
528     // If there is no DIE for address (e.g. it is in unavailable .dwo file),
529     // try to at least get file/line info from symbol table.
530     if (Spec.FLIKind != FileLineInfoKind::None) {
531       DILineInfo Frame;
532       LineTable = getLineTableForUnit(CU);
533       if (LineTable &&
534           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
535                                                Spec.FLIKind, Frame))
536         InliningInfo.addFrame(Frame);
537     }
538     return InliningInfo;
539   }
540 
541   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
542   for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
543     const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
544     DILineInfo Frame;
545     // Get function name if necessary.
546     if (const char *Name =
547             FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
548       Frame.FunctionName = Name;
549     if (Spec.FLIKind != FileLineInfoKind::None) {
550       if (i == 0) {
551         // For the topmost frame, initialize the line table of this
552         // compile unit and fetch file/line info from it.
553         LineTable = getLineTableForUnit(CU);
554         // For the topmost routine, get file/line info from line table.
555         if (LineTable)
556           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
557                                                Spec.FLIKind, Frame);
558       } else {
559         // Otherwise, use call file, call line and call column from
560         // previous DIE in inlined chain.
561         if (LineTable)
562           LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
563                                         Spec.FLIKind, Frame.FileName);
564         Frame.Line = CallLine;
565         Frame.Column = CallColumn;
566       }
567       // Get call file/line/column of a current DIE.
568       if (i + 1 < n) {
569         FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
570                                    CallColumn);
571       }
572     }
573     InliningInfo.addFrame(Frame);
574   }
575   return InliningInfo;
576 }
577 
consumeCompressedDebugSectionHeader(StringRef & data,uint64_t & OriginalSize)578 static bool consumeCompressedDebugSectionHeader(StringRef &data,
579                                                 uint64_t &OriginalSize) {
580   // Consume "ZLIB" prefix.
581   if (!data.startswith("ZLIB"))
582     return false;
583   data = data.substr(4);
584   // Consume uncompressed section size (big-endian 8 bytes).
585   DataExtractor extractor(data, false, 8);
586   uint32_t Offset = 0;
587   OriginalSize = extractor.getU64(&Offset);
588   if (Offset == 0)
589     return false;
590   data = data.substr(Offset);
591   return true;
592 }
593 
DWARFContextInMemory(const object::ObjectFile & Obj,const LoadedObjectInfo * L)594 DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
595     const LoadedObjectInfo *L)
596     : IsLittleEndian(Obj.isLittleEndian()),
597       AddressSize(Obj.getBytesInAddress()) {
598   for (const SectionRef &Section : Obj.sections()) {
599     StringRef name;
600     Section.getName(name);
601     // Skip BSS and Virtual sections, they aren't interesting.
602     bool IsBSS = Section.isBSS();
603     if (IsBSS)
604       continue;
605     bool IsVirtual = Section.isVirtual();
606     if (IsVirtual)
607       continue;
608     StringRef data;
609 
610     section_iterator RelocatedSection = Section.getRelocatedSection();
611     // Try to obtain an already relocated version of this section.
612     // Else use the unrelocated section from the object file. We'll have to
613     // apply relocations ourselves later.
614     if (!L || !L->getLoadedSectionContents(*RelocatedSection,data))
615       Section.getContents(data);
616 
617     name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
618 
619     // Check if debug info section is compressed with zlib.
620     if (name.startswith("zdebug_")) {
621       uint64_t OriginalSize;
622       if (!zlib::isAvailable() ||
623           !consumeCompressedDebugSectionHeader(data, OriginalSize))
624         continue;
625       UncompressedSections.resize(UncompressedSections.size() + 1);
626       if (zlib::uncompress(data, UncompressedSections.back(), OriginalSize) !=
627           zlib::StatusOK) {
628         UncompressedSections.pop_back();
629         continue;
630       }
631       // Make data point to uncompressed section contents and save its contents.
632       name = name.substr(1);
633       data = UncompressedSections.back();
634     }
635 
636     StringRef *SectionData =
637         StringSwitch<StringRef *>(name)
638             .Case("debug_info", &InfoSection.Data)
639             .Case("debug_abbrev", &AbbrevSection)
640             .Case("debug_loc", &LocSection.Data)
641             .Case("debug_line", &LineSection.Data)
642             .Case("debug_aranges", &ARangeSection)
643             .Case("debug_frame", &DebugFrameSection)
644             .Case("debug_str", &StringSection)
645             .Case("debug_ranges", &RangeSection)
646             .Case("debug_macinfo", &MacinfoSection)
647             .Case("debug_pubnames", &PubNamesSection)
648             .Case("debug_pubtypes", &PubTypesSection)
649             .Case("debug_gnu_pubnames", &GnuPubNamesSection)
650             .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
651             .Case("debug_info.dwo", &InfoDWOSection.Data)
652             .Case("debug_abbrev.dwo", &AbbrevDWOSection)
653             .Case("debug_loc.dwo", &LocDWOSection.Data)
654             .Case("debug_line.dwo", &LineDWOSection.Data)
655             .Case("debug_str.dwo", &StringDWOSection)
656             .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
657             .Case("debug_addr", &AddrSection)
658             .Case("apple_names", &AppleNamesSection.Data)
659             .Case("apple_types", &AppleTypesSection.Data)
660             .Case("apple_namespaces", &AppleNamespacesSection.Data)
661             .Case("apple_namespac", &AppleNamespacesSection.Data)
662             .Case("apple_objc", &AppleObjCSection.Data)
663             .Case("debug_cu_index", &CUIndexSection)
664             .Case("debug_tu_index", &TUIndexSection)
665             // Any more debug info sections go here.
666             .Default(nullptr);
667     if (SectionData) {
668       *SectionData = data;
669       if (name == "debug_ranges") {
670         // FIXME: Use the other dwo range section when we emit it.
671         RangeDWOSection = data;
672       }
673     } else if (name == "debug_types") {
674       // Find debug_types data by section rather than name as there are
675       // multiple, comdat grouped, debug_types sections.
676       TypesSections[Section].Data = data;
677     } else if (name == "debug_types.dwo") {
678       TypesDWOSections[Section].Data = data;
679     }
680 
681     if (RelocatedSection == Obj.section_end())
682       continue;
683 
684     StringRef RelSecName;
685     StringRef RelSecData;
686     RelocatedSection->getName(RelSecName);
687 
688     // If the section we're relocating was relocated already by the JIT,
689     // then we used the relocated version above, so we do not need to process
690     // relocations for it now.
691     if (L && L->getLoadedSectionContents(*RelocatedSection,RelSecData))
692       continue;
693 
694     // In Mach-o files, the relocations do not need to be applied if
695     // there is no load offset to apply. The value read at the
696     // relocation point already factors in the section address
697     // (actually applying the relocations will produce wrong results
698     // as the section address will be added twice).
699     if (!L && isa<MachOObjectFile>(&Obj))
700       continue;
701 
702     RelSecName = RelSecName.substr(
703         RelSecName.find_first_not_of("._")); // Skip . and _ prefixes.
704 
705     // TODO: Add support for relocations in other sections as needed.
706     // Record relocations for the debug_info and debug_line sections.
707     RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
708         .Case("debug_info", &InfoSection.Relocs)
709         .Case("debug_loc", &LocSection.Relocs)
710         .Case("debug_info.dwo", &InfoDWOSection.Relocs)
711         .Case("debug_line", &LineSection.Relocs)
712         .Case("apple_names", &AppleNamesSection.Relocs)
713         .Case("apple_types", &AppleTypesSection.Relocs)
714         .Case("apple_namespaces", &AppleNamespacesSection.Relocs)
715         .Case("apple_namespac", &AppleNamespacesSection.Relocs)
716         .Case("apple_objc", &AppleObjCSection.Relocs)
717         .Default(nullptr);
718     if (!Map) {
719       // Find debug_types relocs by section rather than name as there are
720       // multiple, comdat grouped, debug_types sections.
721       if (RelSecName == "debug_types")
722         Map = &TypesSections[*RelocatedSection].Relocs;
723       else if (RelSecName == "debug_types.dwo")
724         Map = &TypesDWOSections[*RelocatedSection].Relocs;
725       else
726         continue;
727     }
728 
729     if (Section.relocation_begin() != Section.relocation_end()) {
730       uint64_t SectionSize = RelocatedSection->getSize();
731       for (const RelocationRef &Reloc : Section.relocations()) {
732         uint64_t Address = Reloc.getOffset();
733         uint64_t Type = Reloc.getType();
734         uint64_t SymAddr = 0;
735         uint64_t SectionLoadAddress = 0;
736         object::symbol_iterator Sym = Reloc.getSymbol();
737         object::section_iterator RSec = Obj.section_end();
738 
739         // First calculate the address of the symbol or section as it appears
740         // in the objct file
741         if (Sym != Obj.symbol_end()) {
742           ErrorOr<uint64_t> SymAddrOrErr = Sym->getAddress();
743           if (std::error_code EC = SymAddrOrErr.getError()) {
744             errs() << "error: failed to compute symbol address: "
745                    << EC.message() << '\n';
746             continue;
747           }
748           SymAddr = *SymAddrOrErr;
749           // Also remember what section this symbol is in for later
750           RSec = *Sym->getSection();
751         } else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
752           // MachO also has relocations that point to sections and
753           // scattered relocations.
754           auto RelocInfo = MObj->getRelocation(Reloc.getRawDataRefImpl());
755           if (MObj->isRelocationScattered(RelocInfo)) {
756             // FIXME: it's not clear how to correctly handle scattered
757             // relocations.
758             continue;
759           } else {
760             RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
761             SymAddr = RSec->getAddress();
762           }
763         }
764 
765         // If we are given load addresses for the sections, we need to adjust:
766         // SymAddr = (Address of Symbol Or Section in File) -
767         //           (Address of Section in File) +
768         //           (Load Address of Section)
769         if (L != nullptr && RSec != Obj.section_end()) {
770           // RSec is now either the section being targeted or the section
771           // containing the symbol being targeted. In either case,
772           // we need to perform the same computation.
773           StringRef SecName;
774           RSec->getName(SecName);
775 //           llvm::dbgs() << "Name: '" << SecName
776 //                        << "', RSec: " << RSec->getRawDataRefImpl()
777 //                        << ", Section: " << Section.getRawDataRefImpl() << "\n";
778           SectionLoadAddress = L->getSectionLoadAddress(*RSec);
779           if (SectionLoadAddress != 0)
780             SymAddr += SectionLoadAddress - RSec->getAddress();
781         }
782 
783         object::RelocVisitor V(Obj);
784         object::RelocToApply R(V.visit(Type, Reloc, SymAddr));
785         if (V.error()) {
786           SmallString<32> Name;
787           Reloc.getTypeName(Name);
788           errs() << "error: failed to compute relocation: "
789                  << Name << "\n";
790           continue;
791         }
792 
793         if (Address + R.Width > SectionSize) {
794           errs() << "error: " << R.Width << "-byte relocation starting "
795                  << Address << " bytes into section " << name << " which is "
796                  << SectionSize << " bytes long.\n";
797           continue;
798         }
799         if (R.Width > 8) {
800           errs() << "error: can't handle a relocation of more than 8 bytes at "
801                     "a time.\n";
802           continue;
803         }
804         DEBUG(dbgs() << "Writing " << format("%p", R.Value)
805                      << " at " << format("%p", Address)
806                      << " with width " << format("%d", R.Width)
807                      << "\n");
808         Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
809       }
810     }
811   }
812 }
813 
anchor()814 void DWARFContextInMemory::anchor() { }
815