DWARFContext.cpp revision 263508 
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 "DWARFContext.h"
11#include "llvm/ADT/SmallString.h"
12#include "llvm/ADT/StringSwitch.h"
13#include "llvm/ADT/STLExtras.h"
14#include "llvm/Support/Compression.h"
15#include "llvm/Support/Dwarf.h"
16#include "llvm/Support/Format.h"
17#include "llvm/Support/Path.h"
18#include "llvm/Support/raw_ostream.h"
19#include <algorithm>
20using namespace llvm;
21using namespace dwarf;
22using namespace object;
23
24typedef DWARFDebugLine::LineTable DWARFLineTable;
25
26DWARFContext::~DWARFContext() {
27  DeleteContainerPointers(CUs);
28  DeleteContainerPointers(TUs);
29  DeleteContainerPointers(DWOCUs);
30}
31
32static 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  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
61void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
62  if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
63    OS << ".debug_abbrev contents:\n";
64    getDebugAbbrev()->dump(OS);
65  }
66
67  if (DumpType == DIDT_All || DumpType == DIDT_Info) {
68    OS << "\n.debug_info contents:\n";
69    for (unsigned i = 0, e = getNumCompileUnits(); i != e; ++i)
70      getCompileUnitAtIndex(i)->dump(OS);
71  }
72
73  if (DumpType == DIDT_All || DumpType == DIDT_Types) {
74    OS << "\n.debug_types contents:\n";
75    for (unsigned i = 0, e = getNumTypeUnits(); i != e; ++i)
76      getTypeUnitAtIndex(i)->dump(OS);
77  }
78
79  if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
80    OS << "\n.debug_loc contents:\n";
81    getDebugLoc()->dump(OS);
82  }
83
84  if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
85    OS << "\n.debug_frame contents:\n";
86    getDebugFrame()->dump(OS);
87  }
88
89  uint32_t offset = 0;
90  if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
91    OS << "\n.debug_aranges contents:\n";
92    DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
93    DWARFDebugArangeSet set;
94    while (set.extract(arangesData, &offset))
95      set.dump(OS);
96  }
97
98  uint8_t savedAddressByteSize = 0;
99  if (DumpType == DIDT_All || DumpType == DIDT_Line) {
100    OS << "\n.debug_line contents:\n";
101    for (unsigned i = 0, e = getNumCompileUnits(); i != e; ++i) {
102      DWARFCompileUnit *cu = getCompileUnitAtIndex(i);
103      savedAddressByteSize = cu->getAddressByteSize();
104      unsigned stmtOffset =
105          cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
106              cu, DW_AT_stmt_list, -1U);
107      if (stmtOffset != -1U) {
108        DataExtractor lineData(getLineSection().Data, isLittleEndian(),
109                               savedAddressByteSize);
110        DWARFDebugLine::DumpingState state(OS);
111        DWARFDebugLine::parseStatementTable(lineData, &getLineSection().Relocs, &stmtOffset, state);
112      }
113    }
114  }
115
116  if (DumpType == DIDT_All || DumpType == DIDT_Str) {
117    OS << "\n.debug_str contents:\n";
118    DataExtractor strData(getStringSection(), isLittleEndian(), 0);
119    offset = 0;
120    uint32_t strOffset = 0;
121    while (const char *s = strData.getCStr(&offset)) {
122      OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
123      strOffset = offset;
124    }
125  }
126
127  if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
128    OS << "\n.debug_ranges contents:\n";
129    // In fact, different compile units may have different address byte
130    // sizes, but for simplicity we just use the address byte size of the last
131    // compile unit (there is no easy and fast way to associate address range
132    // list and the compile unit it describes).
133    DataExtractor rangesData(getRangeSection(), isLittleEndian(),
134                             savedAddressByteSize);
135    offset = 0;
136    DWARFDebugRangeList rangeList;
137    while (rangeList.extract(rangesData, &offset))
138      rangeList.dump(OS);
139  }
140
141  if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
142    dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
143                   isLittleEndian(), false);
144
145  if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
146    dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
147                   isLittleEndian(), false);
148
149  if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
150    dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
151                   isLittleEndian(), true /* GnuStyle */);
152
153  if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
154    dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
155                   isLittleEndian(), true /* GnuStyle */);
156
157  if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo) {
158    const DWARFDebugAbbrev *D = getDebugAbbrevDWO();
159    if (D) {
160      OS << "\n.debug_abbrev.dwo contents:\n";
161      getDebugAbbrevDWO()->dump(OS);
162    }
163  }
164
165  if (DumpType == DIDT_All || DumpType == DIDT_InfoDwo)
166    if (getNumDWOCompileUnits()) {
167      OS << "\n.debug_info.dwo contents:\n";
168      for (unsigned i = 0, e = getNumDWOCompileUnits(); i != e; ++i)
169        getDWOCompileUnitAtIndex(i)->dump(OS);
170    }
171
172  if (DumpType == DIDT_All || DumpType == DIDT_StrDwo)
173    if (!getStringDWOSection().empty()) {
174      OS << "\n.debug_str.dwo contents:\n";
175      DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
176      offset = 0;
177      uint32_t strDWOOffset = 0;
178      while (const char *s = strDWOData.getCStr(&offset)) {
179        OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
180        strDWOOffset = offset;
181      }
182    }
183
184  if (DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo)
185    if (!getStringOffsetDWOSection().empty()) {
186      OS << "\n.debug_str_offsets.dwo contents:\n";
187      DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(), 0);
188      offset = 0;
189      uint64_t size = getStringOffsetDWOSection().size();
190      while (offset < size) {
191        OS << format("0x%8.8x: ", offset);
192        OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
193      }
194    }
195}
196
197const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
198  if (Abbrev)
199    return Abbrev.get();
200
201  DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
202
203  Abbrev.reset(new DWARFDebugAbbrev());
204  Abbrev->parse(abbrData);
205  return Abbrev.get();
206}
207
208const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
209  if (AbbrevDWO)
210    return AbbrevDWO.get();
211
212  DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
213  AbbrevDWO.reset(new DWARFDebugAbbrev());
214  AbbrevDWO->parse(abbrData);
215  return AbbrevDWO.get();
216}
217
218const DWARFDebugLoc *DWARFContext::getDebugLoc() {
219  if (Loc)
220    return Loc.get();
221
222  DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
223  Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
224  // assume all compile units have the same address byte size
225  if (getNumCompileUnits())
226    Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
227  return Loc.get();
228}
229
230const DWARFDebugAranges *DWARFContext::getDebugAranges() {
231  if (Aranges)
232    return Aranges.get();
233
234  Aranges.reset(new DWARFDebugAranges());
235  Aranges->generate(this);
236  return Aranges.get();
237}
238
239const DWARFDebugFrame *DWARFContext::getDebugFrame() {
240  if (DebugFrame)
241    return DebugFrame.get();
242
243  // There's a "bug" in the DWARFv3 standard with respect to the target address
244  // size within debug frame sections. While DWARF is supposed to be independent
245  // of its container, FDEs have fields with size being "target address size",
246  // which isn't specified in DWARF in general. It's only specified for CUs, but
247  // .eh_frame can appear without a .debug_info section. Follow the example of
248  // other tools (libdwarf) and extract this from the container (ObjectFile
249  // provides this information). This problem is fixed in DWARFv4
250  // See this dwarf-discuss discussion for more details:
251  // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
252  DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
253                               getAddressSize());
254  DebugFrame.reset(new DWARFDebugFrame());
255  DebugFrame->parse(debugFrameData);
256  return DebugFrame.get();
257}
258
259const DWARFLineTable *
260DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
261  if (!Line)
262    Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
263
264  unsigned stmtOffset =
265      cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
266          cu, DW_AT_stmt_list, -1U);
267  if (stmtOffset == -1U)
268    return 0; // No line table for this compile unit.
269
270  // See if the line table is cached.
271  if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
272    return lt;
273
274  // We have to parse it first.
275  DataExtractor lineData(getLineSection().Data, isLittleEndian(),
276                         cu->getAddressByteSize());
277  return Line->getOrParseLineTable(lineData, stmtOffset);
278}
279
280void DWARFContext::parseCompileUnits() {
281  uint32_t offset = 0;
282  const DataExtractor &DIData = DataExtractor(getInfoSection().Data,
283                                              isLittleEndian(), 0);
284  while (DIData.isValidOffset(offset)) {
285    OwningPtr<DWARFCompileUnit> CU(new DWARFCompileUnit(
286        getDebugAbbrev(), getInfoSection().Data, getAbbrevSection(),
287        getRangeSection(), getStringSection(), StringRef(), getAddrSection(),
288        &getInfoSection().Relocs, isLittleEndian()));
289    if (!CU->extract(DIData, &offset)) {
290      break;
291    }
292    CUs.push_back(CU.take());
293    offset = CUs.back()->getNextUnitOffset();
294  }
295}
296
297void DWARFContext::parseTypeUnits() {
298  const std::map<object::SectionRef, Section> &Sections = getTypesSections();
299  for (std::map<object::SectionRef, Section>::const_iterator
300           I = Sections.begin(),
301           E = Sections.end();
302       I != E; ++I) {
303    uint32_t offset = 0;
304    const DataExtractor &DIData =
305        DataExtractor(I->second.Data, isLittleEndian(), 0);
306    while (DIData.isValidOffset(offset)) {
307      OwningPtr<DWARFTypeUnit> TU(new DWARFTypeUnit(
308          getDebugAbbrev(), I->second.Data, getAbbrevSection(),
309          getRangeSection(), getStringSection(), StringRef(), getAddrSection(),
310          &I->second.Relocs, isLittleEndian()));
311      if (!TU->extract(DIData, &offset))
312        break;
313      TUs.push_back(TU.take());
314      offset = TUs.back()->getNextUnitOffset();
315    }
316  }
317}
318
319void DWARFContext::parseDWOCompileUnits() {
320  uint32_t offset = 0;
321  const DataExtractor &DIData =
322      DataExtractor(getInfoDWOSection().Data, isLittleEndian(), 0);
323  while (DIData.isValidOffset(offset)) {
324    OwningPtr<DWARFCompileUnit> DWOCU(new DWARFCompileUnit(
325        getDebugAbbrevDWO(), getInfoDWOSection().Data, getAbbrevDWOSection(),
326        getRangeDWOSection(), getStringDWOSection(),
327        getStringOffsetDWOSection(), getAddrSection(),
328        &getInfoDWOSection().Relocs, isLittleEndian()));
329    if (!DWOCU->extract(DIData, &offset)) {
330      break;
331    }
332    DWOCUs.push_back(DWOCU.take());
333    offset = DWOCUs.back()->getNextUnitOffset();
334  }
335}
336
337namespace {
338  struct OffsetComparator {
339    bool operator()(const DWARFCompileUnit *LHS,
340                    const DWARFCompileUnit *RHS) const {
341      return LHS->getOffset() < RHS->getOffset();
342    }
343    bool operator()(const DWARFCompileUnit *LHS, uint32_t RHS) const {
344      return LHS->getOffset() < RHS;
345    }
346    bool operator()(uint32_t LHS, const DWARFCompileUnit *RHS) const {
347      return LHS < RHS->getOffset();
348    }
349  };
350}
351
352DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
353  if (CUs.empty())
354    parseCompileUnits();
355
356  DWARFCompileUnit **CU =
357      std::lower_bound(CUs.begin(), CUs.end(), Offset, OffsetComparator());
358  if (CU != CUs.end()) {
359    return *CU;
360  }
361  return 0;
362}
363
364DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
365  // First, get the offset of the compile unit.
366  uint32_t CUOffset = getDebugAranges()->findAddress(Address);
367  // Retrieve the compile unit.
368  return getCompileUnitForOffset(CUOffset);
369}
370
371static bool getFileNameForCompileUnit(DWARFCompileUnit *CU,
372                                      const DWARFLineTable *LineTable,
373                                      uint64_t FileIndex,
374                                      bool NeedsAbsoluteFilePath,
375                                      std::string &FileName) {
376  if (CU == 0 ||
377      LineTable == 0 ||
378      !LineTable->getFileNameByIndex(FileIndex, NeedsAbsoluteFilePath,
379                                     FileName))
380    return false;
381  if (NeedsAbsoluteFilePath && sys::path::is_relative(FileName)) {
382    // We may still need to append compilation directory of compile unit.
383    SmallString<16> AbsolutePath;
384    if (const char *CompilationDir = CU->getCompilationDir()) {
385      sys::path::append(AbsolutePath, CompilationDir);
386    }
387    sys::path::append(AbsolutePath, FileName);
388    FileName = AbsolutePath.str();
389  }
390  return true;
391}
392
393static bool getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
394                                          const DWARFLineTable *LineTable,
395                                          uint64_t Address,
396                                          bool NeedsAbsoluteFilePath,
397                                          std::string &FileName,
398                                          uint32_t &Line, uint32_t &Column) {
399  if (CU == 0 || LineTable == 0)
400    return false;
401  // Get the index of row we're looking for in the line table.
402  uint32_t RowIndex = LineTable->lookupAddress(Address);
403  if (RowIndex == -1U)
404    return false;
405  // Take file number and line/column from the row.
406  const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
407  if (!getFileNameForCompileUnit(CU, LineTable, Row.File,
408                                 NeedsAbsoluteFilePath, FileName))
409    return false;
410  Line = Row.Line;
411  Column = Row.Column;
412  return true;
413}
414
415DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
416    DILineInfoSpecifier Specifier) {
417  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
418  if (!CU)
419    return DILineInfo();
420  std::string FileName = "<invalid>";
421  std::string FunctionName = "<invalid>";
422  uint32_t Line = 0;
423  uint32_t Column = 0;
424  if (Specifier.needs(DILineInfoSpecifier::FunctionName)) {
425    // The address may correspond to instruction in some inlined function,
426    // so we have to build the chain of inlined functions and take the
427    // name of the topmost function in it.
428    const DWARFDebugInfoEntryInlinedChain &InlinedChain =
429        CU->getInlinedChainForAddress(Address);
430    if (InlinedChain.DIEs.size() > 0) {
431      const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
432      if (const char *Name = TopFunctionDIE.getSubroutineName(InlinedChain.U))
433        FunctionName = Name;
434    }
435  }
436  if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
437    const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
438    const bool NeedsAbsoluteFilePath =
439        Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
440    getFileLineInfoForCompileUnit(CU, LineTable, Address,
441                                  NeedsAbsoluteFilePath,
442                                  FileName, Line, Column);
443  }
444  return DILineInfo(StringRef(FileName), StringRef(FunctionName),
445                    Line, Column);
446}
447
448DILineInfoTable DWARFContext::getLineInfoForAddressRange(uint64_t Address,
449    uint64_t Size,
450    DILineInfoSpecifier Specifier) {
451  DILineInfoTable  Lines;
452  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
453  if (!CU)
454    return Lines;
455
456  std::string FunctionName = "<invalid>";
457  if (Specifier.needs(DILineInfoSpecifier::FunctionName)) {
458    // The address may correspond to instruction in some inlined function,
459    // so we have to build the chain of inlined functions and take the
460    // name of the topmost function in it.
461    const DWARFDebugInfoEntryInlinedChain &InlinedChain =
462        CU->getInlinedChainForAddress(Address);
463    if (InlinedChain.DIEs.size() > 0) {
464      const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
465      if (const char *Name = TopFunctionDIE.getSubroutineName(InlinedChain.U))
466        FunctionName = Name;
467    }
468  }
469
470  // If the Specifier says we don't need FileLineInfo, just
471  // return the top-most function at the starting address.
472  if (!Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
473    Lines.push_back(
474        std::make_pair(Address, DILineInfo("<invalid>", FunctionName, 0, 0)));
475    return Lines;
476  }
477
478  const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
479  const bool NeedsAbsoluteFilePath =
480      Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
481
482  // Get the index of row we're looking for in the line table.
483  std::vector<uint32_t> RowVector;
484  if (!LineTable->lookupAddressRange(Address, Size, RowVector))
485    return Lines;
486
487  uint32_t NumRows = RowVector.size();
488  for (uint32_t i = 0; i < NumRows; ++i) {
489    uint32_t RowIndex = RowVector[i];
490    // Take file number and line/column from the row.
491    const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
492    std::string FileName = "<invalid>";
493    getFileNameForCompileUnit(CU, LineTable, Row.File,
494                              NeedsAbsoluteFilePath, FileName);
495    Lines.push_back(std::make_pair(
496        Row.Address, DILineInfo(FileName, FunctionName, Row.Line, Row.Column)));
497  }
498
499  return Lines;
500}
501
502DIInliningInfo DWARFContext::getInliningInfoForAddress(uint64_t Address,
503    DILineInfoSpecifier Specifier) {
504  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
505  if (!CU)
506    return DIInliningInfo();
507
508  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
509      CU->getInlinedChainForAddress(Address);
510  if (InlinedChain.DIEs.size() == 0)
511    return DIInliningInfo();
512
513  DIInliningInfo InliningInfo;
514  uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
515  const DWARFLineTable *LineTable = 0;
516  for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
517    const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
518    std::string FileName = "<invalid>";
519    std::string FunctionName = "<invalid>";
520    uint32_t Line = 0;
521    uint32_t Column = 0;
522    // Get function name if necessary.
523    if (Specifier.needs(DILineInfoSpecifier::FunctionName)) {
524      if (const char *Name = FunctionDIE.getSubroutineName(InlinedChain.U))
525        FunctionName = Name;
526    }
527    if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
528      const bool NeedsAbsoluteFilePath =
529          Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
530      if (i == 0) {
531        // For the topmost frame, initialize the line table of this
532        // compile unit and fetch file/line info from it.
533        LineTable = getLineTableForCompileUnit(CU);
534        // For the topmost routine, get file/line info from line table.
535        getFileLineInfoForCompileUnit(CU, LineTable, Address,
536                                      NeedsAbsoluteFilePath,
537                                      FileName, Line, Column);
538      } else {
539        // Otherwise, use call file, call line and call column from
540        // previous DIE in inlined chain.
541        getFileNameForCompileUnit(CU, LineTable, CallFile,
542                                  NeedsAbsoluteFilePath, FileName);
543        Line = CallLine;
544        Column = CallColumn;
545      }
546      // Get call file/line/column of a current DIE.
547      if (i + 1 < n) {
548        FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
549                                   CallColumn);
550      }
551    }
552    DILineInfo Frame(StringRef(FileName), StringRef(FunctionName),
553                     Line, Column);
554    InliningInfo.addFrame(Frame);
555  }
556  return InliningInfo;
557}
558
559static bool consumeCompressedDebugSectionHeader(StringRef &data,
560                                                uint64_t &OriginalSize) {
561  // Consume "ZLIB" prefix.
562  if (!data.startswith("ZLIB"))
563    return false;
564  data = data.substr(4);
565  // Consume uncompressed section size (big-endian 8 bytes).
566  DataExtractor extractor(data, false, 8);
567  uint32_t Offset = 0;
568  OriginalSize = extractor.getU64(&Offset);
569  if (Offset == 0)
570    return false;
571  data = data.substr(Offset);
572  return true;
573}
574
575DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj) :
576  IsLittleEndian(Obj->isLittleEndian()),
577  AddressSize(Obj->getBytesInAddress()) {
578  error_code ec;
579  for (object::section_iterator i = Obj->begin_sections(),
580         e = Obj->end_sections();
581       i != e; i.increment(ec)) {
582    StringRef name;
583    i->getName(name);
584    StringRef data;
585    i->getContents(data);
586
587    name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
588
589    // Check if debug info section is compressed with zlib.
590    if (name.startswith("zdebug_")) {
591      uint64_t OriginalSize;
592      if (!zlib::isAvailable() ||
593          !consumeCompressedDebugSectionHeader(data, OriginalSize))
594        continue;
595      OwningPtr<MemoryBuffer> UncompressedSection;
596      if (zlib::uncompress(data, UncompressedSection, OriginalSize) !=
597          zlib::StatusOK)
598        continue;
599      // Make data point to uncompressed section contents and save its contents.
600      name = name.substr(1);
601      data = UncompressedSection->getBuffer();
602      UncompressedSections.push_back(UncompressedSection.take());
603    }
604
605    StringRef *Section =
606        StringSwitch<StringRef *>(name)
607            .Case("debug_info", &InfoSection.Data)
608            .Case("debug_abbrev", &AbbrevSection)
609            .Case("debug_loc", &LocSection.Data)
610            .Case("debug_line", &LineSection.Data)
611            .Case("debug_aranges", &ARangeSection)
612            .Case("debug_frame", &DebugFrameSection)
613            .Case("debug_str", &StringSection)
614            .Case("debug_ranges", &RangeSection)
615            .Case("debug_pubnames", &PubNamesSection)
616            .Case("debug_pubtypes", &PubTypesSection)
617            .Case("debug_gnu_pubnames", &GnuPubNamesSection)
618            .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
619            .Case("debug_info.dwo", &InfoDWOSection.Data)
620            .Case("debug_abbrev.dwo", &AbbrevDWOSection)
621            .Case("debug_str.dwo", &StringDWOSection)
622            .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
623            .Case("debug_addr", &AddrSection)
624            // Any more debug info sections go here.
625            .Default(0);
626    if (Section) {
627      *Section = data;
628      if (name == "debug_ranges") {
629        // FIXME: Use the other dwo range section when we emit it.
630        RangeDWOSection = data;
631      }
632    } else if (name == "debug_types") {
633      // Find debug_types data by section rather than name as there are
634      // multiple, comdat grouped, debug_types sections.
635      TypesSections[*i].Data = data;
636    }
637
638    section_iterator RelocatedSection = i->getRelocatedSection();
639    if (RelocatedSection == Obj->end_sections())
640      continue;
641
642    StringRef RelSecName;
643    RelocatedSection->getName(RelSecName);
644    RelSecName = RelSecName.substr(
645        RelSecName.find_first_not_of("._")); // Skip . and _ prefixes.
646
647    // TODO: Add support for relocations in other sections as needed.
648    // Record relocations for the debug_info and debug_line sections.
649    RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
650        .Case("debug_info", &InfoSection.Relocs)
651        .Case("debug_loc", &LocSection.Relocs)
652        .Case("debug_info.dwo", &InfoDWOSection.Relocs)
653        .Case("debug_line", &LineSection.Relocs)
654        .Default(0);
655    if (!Map) {
656      if (RelSecName != "debug_types")
657        continue;
658      // Find debug_types relocs by section rather than name as there are
659      // multiple, comdat grouped, debug_types sections.
660      Map = &TypesSections[*RelocatedSection].Relocs;
661    }
662
663    if (i->begin_relocations() != i->end_relocations()) {
664      uint64_t SectionSize;
665      RelocatedSection->getSize(SectionSize);
666      for (object::relocation_iterator reloc_i = i->begin_relocations(),
667             reloc_e = i->end_relocations();
668           reloc_i != reloc_e; reloc_i.increment(ec)) {
669        uint64_t Address;
670        reloc_i->getOffset(Address);
671        uint64_t Type;
672        reloc_i->getType(Type);
673        uint64_t SymAddr = 0;
674        // ELF relocations may need the symbol address
675        if (Obj->isELF()) {
676          object::symbol_iterator Sym = reloc_i->getSymbol();
677          Sym->getAddress(SymAddr);
678        }
679
680        object::RelocVisitor V(Obj->getFileFormatName());
681        // The section address is always 0 for debug sections.
682        object::RelocToApply R(V.visit(Type, *reloc_i, 0, SymAddr));
683        if (V.error()) {
684          SmallString<32> Name;
685          error_code ec(reloc_i->getTypeName(Name));
686          if (ec) {
687            errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n";
688          }
689          errs() << "error: failed to compute relocation: "
690                 << Name << "\n";
691          continue;
692        }
693
694        if (Address + R.Width > SectionSize) {
695          errs() << "error: " << R.Width << "-byte relocation starting "
696                 << Address << " bytes into section " << name << " which is "
697                 << SectionSize << " bytes long.\n";
698          continue;
699        }
700        if (R.Width > 8) {
701          errs() << "error: can't handle a relocation of more than 8 bytes at "
702                    "a time.\n";
703          continue;
704        }
705        DEBUG(dbgs() << "Writing " << format("%p", R.Value)
706                     << " at " << format("%p", Address)
707                     << " with width " << format("%d", R.Width)
708                     << "\n");
709        Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
710      }
711    }
712  }
713}
714
715DWARFContextInMemory::~DWARFContextInMemory() {
716  DeleteContainerPointers(UncompressedSections);
717}
718
719void DWARFContextInMemory::anchor() { }
720