DWARFContext.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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 "DWARFDebugArangeSet.h"
12
13#include "llvm/ADT/SmallString.h"
14#include "llvm/ADT/StringSwitch.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>
21using namespace llvm;
22using namespace dwarf;
23using namespace object;
24
25#define DEBUG_TYPE "dwarf"
26
27typedef DWARFDebugLine::LineTable DWARFLineTable;
28typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind;
29typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
30
31static 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
62void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
63  if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
64    OS << ".debug_abbrev contents:\n";
65    getDebugAbbrev()->dump(OS);
66  }
67
68  if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo)
69    if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) {
70      OS << "\n.debug_abbrev.dwo contents:\n";
71      D->dump(OS);
72    }
73
74  if (DumpType == DIDT_All || DumpType == DIDT_Info) {
75    OS << "\n.debug_info contents:\n";
76    for (const auto &CU : compile_units())
77      CU->dump(OS);
78  }
79
80  if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) &&
81      getNumDWOCompileUnits()) {
82    OS << "\n.debug_info.dwo contents:\n";
83    for (const auto &DWOCU : dwo_compile_units())
84      DWOCU->dump(OS);
85  }
86
87  if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
88    OS << "\n.debug_types contents:\n";
89    for (const auto &TU : type_units())
90      TU->dump(OS);
91  }
92
93  if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
94      getNumDWOTypeUnits()) {
95    OS << "\n.debug_types.dwo contents:\n";
96    for (const auto &DWOTU : dwo_type_units())
97      DWOTU->dump(OS);
98  }
99
100  if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
101    OS << "\n.debug_loc contents:\n";
102    getDebugLoc()->dump(OS);
103  }
104
105  if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
106    OS << "\n.debug_loc.dwo contents:\n";
107    getDebugLocDWO()->dump(OS);
108  }
109
110  if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
111    OS << "\n.debug_frame contents:\n";
112    getDebugFrame()->dump(OS);
113  }
114
115  uint32_t offset = 0;
116  if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
117    OS << "\n.debug_aranges contents:\n";
118    DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
119    DWARFDebugArangeSet set;
120    while (set.extract(arangesData, &offset))
121      set.dump(OS);
122  }
123
124  uint8_t savedAddressByteSize = 0;
125  if (DumpType == DIDT_All || DumpType == DIDT_Line) {
126    OS << "\n.debug_line contents:\n";
127    for (const auto &CU : compile_units()) {
128      savedAddressByteSize = CU->getAddressByteSize();
129      unsigned stmtOffset =
130          CU->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
131              CU.get(), DW_AT_stmt_list, -1U);
132      if (stmtOffset != -1U) {
133        DataExtractor lineData(getLineSection().Data, isLittleEndian(),
134                               savedAddressByteSize);
135        DWARFDebugLine::LineTable LineTable;
136        LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
137        LineTable.dump(OS);
138      }
139    }
140  }
141
142  if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
143    OS << "\n.debug_line.dwo contents:\n";
144    unsigned stmtOffset = 0;
145    DataExtractor lineData(getLineDWOSection().Data, isLittleEndian(),
146                           savedAddressByteSize);
147    DWARFDebugLine::LineTable LineTable;
148    while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
149      LineTable.dump(OS);
150      LineTable.clear();
151    }
152  }
153
154  if (DumpType == DIDT_All || DumpType == DIDT_Str) {
155    OS << "\n.debug_str contents:\n";
156    DataExtractor strData(getStringSection(), isLittleEndian(), 0);
157    offset = 0;
158    uint32_t strOffset = 0;
159    while (const char *s = strData.getCStr(&offset)) {
160      OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
161      strOffset = offset;
162    }
163  }
164
165  if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
166      !getStringDWOSection().empty()) {
167    OS << "\n.debug_str.dwo contents:\n";
168    DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
169    offset = 0;
170    uint32_t strDWOOffset = 0;
171    while (const char *s = strDWOData.getCStr(&offset)) {
172      OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
173      strDWOOffset = offset;
174    }
175  }
176
177  if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
178    OS << "\n.debug_ranges contents:\n";
179    // In fact, different compile units may have different address byte
180    // sizes, but for simplicity we just use the address byte size of the last
181    // compile unit (there is no easy and fast way to associate address range
182    // list and the compile unit it describes).
183    DataExtractor rangesData(getRangeSection(), isLittleEndian(),
184                             savedAddressByteSize);
185    offset = 0;
186    DWARFDebugRangeList rangeList;
187    while (rangeList.extract(rangesData, &offset))
188      rangeList.dump(OS);
189  }
190
191  if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
192    dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
193                   isLittleEndian(), false);
194
195  if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
196    dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
197                   isLittleEndian(), false);
198
199  if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
200    dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
201                   isLittleEndian(), true /* GnuStyle */);
202
203  if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
204    dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
205                   isLittleEndian(), true /* GnuStyle */);
206
207  if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) &&
208      !getStringOffsetDWOSection().empty()) {
209    OS << "\n.debug_str_offsets.dwo contents:\n";
210    DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(),
211                               0);
212    offset = 0;
213    uint64_t size = getStringOffsetDWOSection().size();
214    while (offset < size) {
215      OS << format("0x%8.8x: ", offset);
216      OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
217    }
218  }
219}
220
221const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
222  if (Abbrev)
223    return Abbrev.get();
224
225  DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
226
227  Abbrev.reset(new DWARFDebugAbbrev());
228  Abbrev->extract(abbrData);
229  return Abbrev.get();
230}
231
232const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
233  if (AbbrevDWO)
234    return AbbrevDWO.get();
235
236  DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
237  AbbrevDWO.reset(new DWARFDebugAbbrev());
238  AbbrevDWO->extract(abbrData);
239  return AbbrevDWO.get();
240}
241
242const DWARFDebugLoc *DWARFContext::getDebugLoc() {
243  if (Loc)
244    return Loc.get();
245
246  DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
247  Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
248  // assume all compile units have the same address byte size
249  if (getNumCompileUnits())
250    Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
251  return Loc.get();
252}
253
254const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
255  if (LocDWO)
256    return LocDWO.get();
257
258  DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0);
259  LocDWO.reset(new DWARFDebugLocDWO());
260  LocDWO->parse(LocData);
261  return LocDWO.get();
262}
263
264const DWARFDebugAranges *DWARFContext::getDebugAranges() {
265  if (Aranges)
266    return Aranges.get();
267
268  Aranges.reset(new DWARFDebugAranges());
269  Aranges->generate(this);
270  return Aranges.get();
271}
272
273const DWARFDebugFrame *DWARFContext::getDebugFrame() {
274  if (DebugFrame)
275    return DebugFrame.get();
276
277  // There's a "bug" in the DWARFv3 standard with respect to the target address
278  // size within debug frame sections. While DWARF is supposed to be independent
279  // of its container, FDEs have fields with size being "target address size",
280  // which isn't specified in DWARF in general. It's only specified for CUs, but
281  // .eh_frame can appear without a .debug_info section. Follow the example of
282  // other tools (libdwarf) and extract this from the container (ObjectFile
283  // provides this information). This problem is fixed in DWARFv4
284  // See this dwarf-discuss discussion for more details:
285  // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
286  DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
287                               getAddressSize());
288  DebugFrame.reset(new DWARFDebugFrame());
289  DebugFrame->parse(debugFrameData);
290  return DebugFrame.get();
291}
292
293const DWARFLineTable *
294DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
295  if (!Line)
296    Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
297
298  unsigned stmtOffset =
299      cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
300          cu, DW_AT_stmt_list, -1U);
301  if (stmtOffset == -1U)
302    return nullptr; // No line table for this compile unit.
303
304  // See if the line table is cached.
305  if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
306    return lt;
307
308  // We have to parse it first.
309  DataExtractor lineData(getLineSection().Data, isLittleEndian(),
310                         cu->getAddressByteSize());
311  return Line->getOrParseLineTable(lineData, stmtOffset);
312}
313
314void DWARFContext::parseCompileUnits() {
315  if (!CUs.empty())
316    return;
317  uint32_t offset = 0;
318  const DataExtractor &DIData = DataExtractor(getInfoSection().Data,
319                                              isLittleEndian(), 0);
320  while (DIData.isValidOffset(offset)) {
321    std::unique_ptr<DWARFCompileUnit> CU(new DWARFCompileUnit(
322        getDebugAbbrev(), getInfoSection().Data, getRangeSection(),
323        getStringSection(), StringRef(), getAddrSection(),
324        &getInfoSection().Relocs, isLittleEndian()));
325    if (!CU->extract(DIData, &offset)) {
326      break;
327    }
328    CUs.push_back(std::move(CU));
329    offset = CUs.back()->getNextUnitOffset();
330  }
331}
332
333void DWARFContext::parseTypeUnits() {
334  if (!TUs.empty())
335    return;
336  for (const auto &I : getTypesSections()) {
337    uint32_t offset = 0;
338    const DataExtractor &DIData =
339        DataExtractor(I.second.Data, isLittleEndian(), 0);
340    while (DIData.isValidOffset(offset)) {
341      std::unique_ptr<DWARFTypeUnit> TU(
342          new DWARFTypeUnit(getDebugAbbrev(), I.second.Data, getRangeSection(),
343                            getStringSection(), StringRef(), getAddrSection(),
344                            &I.second.Relocs, isLittleEndian()));
345      if (!TU->extract(DIData, &offset))
346        break;
347      TUs.push_back(std::move(TU));
348      offset = TUs.back()->getNextUnitOffset();
349    }
350  }
351}
352
353void DWARFContext::parseDWOCompileUnits() {
354  if (!DWOCUs.empty())
355    return;
356  uint32_t offset = 0;
357  const DataExtractor &DIData =
358      DataExtractor(getInfoDWOSection().Data, isLittleEndian(), 0);
359  while (DIData.isValidOffset(offset)) {
360    std::unique_ptr<DWARFCompileUnit> DWOCU(new DWARFCompileUnit(
361        getDebugAbbrevDWO(), getInfoDWOSection().Data, getRangeDWOSection(),
362        getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
363        &getInfoDWOSection().Relocs, isLittleEndian()));
364    if (!DWOCU->extract(DIData, &offset)) {
365      break;
366    }
367    DWOCUs.push_back(std::move(DWOCU));
368    offset = DWOCUs.back()->getNextUnitOffset();
369  }
370}
371
372void DWARFContext::parseDWOTypeUnits() {
373  if (!DWOTUs.empty())
374    return;
375  for (const auto &I : getTypesDWOSections()) {
376    uint32_t offset = 0;
377    const DataExtractor &DIData =
378        DataExtractor(I.second.Data, isLittleEndian(), 0);
379    while (DIData.isValidOffset(offset)) {
380      std::unique_ptr<DWARFTypeUnit> TU(new DWARFTypeUnit(
381          getDebugAbbrevDWO(), I.second.Data, getRangeDWOSection(),
382          getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
383          &I.second.Relocs, isLittleEndian()));
384      if (!TU->extract(DIData, &offset))
385        break;
386      DWOTUs.push_back(std::move(TU));
387      offset = DWOTUs.back()->getNextUnitOffset();
388    }
389  }
390}
391
392namespace {
393  struct OffsetComparator {
394
395    bool operator()(const std::unique_ptr<DWARFCompileUnit> &LHS,
396                    const std::unique_ptr<DWARFCompileUnit> &RHS) const {
397      return LHS->getOffset() < RHS->getOffset();
398    }
399    bool operator()(const std::unique_ptr<DWARFCompileUnit> &LHS,
400                    uint32_t RHS) const {
401      return LHS->getOffset() < RHS;
402    }
403    bool operator()(uint32_t LHS,
404                    const std::unique_ptr<DWARFCompileUnit> &RHS) const {
405      return LHS < RHS->getOffset();
406    }
407  };
408}
409
410DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
411  parseCompileUnits();
412
413  std::unique_ptr<DWARFCompileUnit> *CU =
414      std::lower_bound(CUs.begin(), CUs.end(), Offset, OffsetComparator());
415  if (CU != CUs.end()) {
416    return CU->get();
417  }
418  return nullptr;
419}
420
421DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
422  // First, get the offset of the compile unit.
423  uint32_t CUOffset = getDebugAranges()->findAddress(Address);
424  // Retrieve the compile unit.
425  return getCompileUnitForOffset(CUOffset);
426}
427
428static bool getFileNameForCompileUnit(DWARFCompileUnit *CU,
429                                      const DWARFLineTable *LineTable,
430                                      uint64_t FileIndex, FileLineInfoKind Kind,
431                                      std::string &FileName) {
432  if (!CU || !LineTable || Kind == FileLineInfoKind::None ||
433      !LineTable->getFileNameByIndex(FileIndex, Kind, FileName))
434    return false;
435  if (Kind == FileLineInfoKind::AbsoluteFilePath &&
436      sys::path::is_relative(FileName)) {
437    // We may still need to append compilation directory of compile unit.
438    SmallString<16> AbsolutePath;
439    if (const char *CompilationDir = CU->getCompilationDir()) {
440      sys::path::append(AbsolutePath, CompilationDir);
441    }
442    sys::path::append(AbsolutePath, FileName);
443    FileName = AbsolutePath.str();
444  }
445  return true;
446}
447
448static bool getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
449                                          const DWARFLineTable *LineTable,
450                                          uint64_t Address,
451                                          FileLineInfoKind Kind,
452                                          DILineInfo &Result) {
453  if (!CU || !LineTable)
454    return false;
455  // Get the index of row we're looking for in the line table.
456  uint32_t RowIndex = LineTable->lookupAddress(Address);
457  if (RowIndex == -1U)
458    return false;
459  // Take file number and line/column from the row.
460  const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
461  if (!getFileNameForCompileUnit(CU, LineTable, Row.File, Kind,
462                                 Result.FileName))
463    return false;
464  Result.Line = Row.Line;
465  Result.Column = Row.Column;
466  return true;
467}
468
469static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
470                                      FunctionNameKind Kind,
471                                      std::string &FunctionName) {
472  if (Kind == FunctionNameKind::None)
473    return false;
474  // The address may correspond to instruction in some inlined function,
475  // so we have to build the chain of inlined functions and take the
476  // name of the topmost function in it.
477  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
478      CU->getInlinedChainForAddress(Address);
479  if (InlinedChain.DIEs.size() == 0)
480    return false;
481  const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
482  if (const char *Name =
483          TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
484    FunctionName = Name;
485    return true;
486  }
487  return false;
488}
489
490DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
491                                               DILineInfoSpecifier Spec) {
492  DILineInfo Result;
493
494  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
495  if (!CU)
496    return Result;
497  getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
498  if (Spec.FLIKind != FileLineInfoKind::None) {
499    const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
500    getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind, Result);
501  }
502  return Result;
503}
504
505DILineInfoTable
506DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
507                                         DILineInfoSpecifier Spec) {
508  DILineInfoTable  Lines;
509  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
510  if (!CU)
511    return Lines;
512
513  std::string FunctionName = "<invalid>";
514  getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName);
515
516  // If the Specifier says we don't need FileLineInfo, just
517  // return the top-most function at the starting address.
518  if (Spec.FLIKind == FileLineInfoKind::None) {
519    DILineInfo Result;
520    Result.FunctionName = FunctionName;
521    Lines.push_back(std::make_pair(Address, Result));
522    return Lines;
523  }
524
525  const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
526
527  // Get the index of row we're looking for in the line table.
528  std::vector<uint32_t> RowVector;
529  if (!LineTable->lookupAddressRange(Address, Size, RowVector))
530    return Lines;
531
532  for (uint32_t RowIndex : RowVector) {
533    // Take file number and line/column from the row.
534    const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
535    DILineInfo Result;
536    getFileNameForCompileUnit(CU, LineTable, Row.File, Spec.FLIKind,
537                              Result.FileName);
538    Result.FunctionName = FunctionName;
539    Result.Line = Row.Line;
540    Result.Column = Row.Column;
541    Lines.push_back(std::make_pair(Row.Address, Result));
542  }
543
544  return Lines;
545}
546
547DIInliningInfo
548DWARFContext::getInliningInfoForAddress(uint64_t Address,
549                                        DILineInfoSpecifier Spec) {
550  DIInliningInfo InliningInfo;
551
552  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
553  if (!CU)
554    return InliningInfo;
555
556  const DWARFLineTable *LineTable = nullptr;
557  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
558      CU->getInlinedChainForAddress(Address);
559  if (InlinedChain.DIEs.size() == 0) {
560    // If there is no DIE for address (e.g. it is in unavailable .dwo file),
561    // try to at least get file/line info from symbol table.
562    if (Spec.FLIKind != FileLineInfoKind::None) {
563      DILineInfo Frame;
564      LineTable = getLineTableForCompileUnit(CU);
565      if (getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind,
566                                        Frame)) {
567        InliningInfo.addFrame(Frame);
568      }
569    }
570    return InliningInfo;
571  }
572
573  uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
574  for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
575    const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
576    DILineInfo Frame;
577    // Get function name if necessary.
578    if (const char *Name =
579            FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
580      Frame.FunctionName = Name;
581    if (Spec.FLIKind != FileLineInfoKind::None) {
582      if (i == 0) {
583        // For the topmost frame, initialize the line table of this
584        // compile unit and fetch file/line info from it.
585        LineTable = getLineTableForCompileUnit(CU);
586        // For the topmost routine, get file/line info from line table.
587        getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind,
588                                      Frame);
589      } else {
590        // Otherwise, use call file, call line and call column from
591        // previous DIE in inlined chain.
592        getFileNameForCompileUnit(CU, LineTable, CallFile, Spec.FLIKind,
593                                  Frame.FileName);
594        Frame.Line = CallLine;
595        Frame.Column = CallColumn;
596      }
597      // Get call file/line/column of a current DIE.
598      if (i + 1 < n) {
599        FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
600                                   CallColumn);
601      }
602    }
603    InliningInfo.addFrame(Frame);
604  }
605  return InliningInfo;
606}
607
608static bool consumeCompressedDebugSectionHeader(StringRef &data,
609                                                uint64_t &OriginalSize) {
610  // Consume "ZLIB" prefix.
611  if (!data.startswith("ZLIB"))
612    return false;
613  data = data.substr(4);
614  // Consume uncompressed section size (big-endian 8 bytes).
615  DataExtractor extractor(data, false, 8);
616  uint32_t Offset = 0;
617  OriginalSize = extractor.getU64(&Offset);
618  if (Offset == 0)
619    return false;
620  data = data.substr(Offset);
621  return true;
622}
623
624DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
625    : IsLittleEndian(Obj->isLittleEndian()),
626      AddressSize(Obj->getBytesInAddress()) {
627  for (const SectionRef &Section : Obj->sections()) {
628    StringRef name;
629    Section.getName(name);
630    StringRef data;
631    Section.getContents(data);
632
633    name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
634
635    // Check if debug info section is compressed with zlib.
636    if (name.startswith("zdebug_")) {
637      uint64_t OriginalSize;
638      if (!zlib::isAvailable() ||
639          !consumeCompressedDebugSectionHeader(data, OriginalSize))
640        continue;
641      UncompressedSections.resize(UncompressedSections.size() + 1);
642      if (zlib::uncompress(data, UncompressedSections.back(), OriginalSize) !=
643          zlib::StatusOK) {
644        UncompressedSections.pop_back();
645        continue;
646      }
647      // Make data point to uncompressed section contents and save its contents.
648      name = name.substr(1);
649      data = UncompressedSections.back();
650    }
651
652    StringRef *SectionData =
653        StringSwitch<StringRef *>(name)
654            .Case("debug_info", &InfoSection.Data)
655            .Case("debug_abbrev", &AbbrevSection)
656            .Case("debug_loc", &LocSection.Data)
657            .Case("debug_line", &LineSection.Data)
658            .Case("debug_aranges", &ARangeSection)
659            .Case("debug_frame", &DebugFrameSection)
660            .Case("debug_str", &StringSection)
661            .Case("debug_ranges", &RangeSection)
662            .Case("debug_pubnames", &PubNamesSection)
663            .Case("debug_pubtypes", &PubTypesSection)
664            .Case("debug_gnu_pubnames", &GnuPubNamesSection)
665            .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
666            .Case("debug_info.dwo", &InfoDWOSection.Data)
667            .Case("debug_abbrev.dwo", &AbbrevDWOSection)
668            .Case("debug_loc.dwo", &LocDWOSection.Data)
669            .Case("debug_line.dwo", &LineDWOSection.Data)
670            .Case("debug_str.dwo", &StringDWOSection)
671            .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
672            .Case("debug_addr", &AddrSection)
673            // Any more debug info sections go here.
674            .Default(nullptr);
675    if (SectionData) {
676      *SectionData = data;
677      if (name == "debug_ranges") {
678        // FIXME: Use the other dwo range section when we emit it.
679        RangeDWOSection = data;
680      }
681    } else if (name == "debug_types") {
682      // Find debug_types data by section rather than name as there are
683      // multiple, comdat grouped, debug_types sections.
684      TypesSections[Section].Data = data;
685    } else if (name == "debug_types.dwo") {
686      TypesDWOSections[Section].Data = data;
687    }
688
689    section_iterator RelocatedSection = Section.getRelocatedSection();
690    if (RelocatedSection == Obj->section_end())
691      continue;
692
693    StringRef RelSecName;
694    RelocatedSection->getName(RelSecName);
695    RelSecName = RelSecName.substr(
696        RelSecName.find_first_not_of("._")); // Skip . and _ prefixes.
697
698    // TODO: Add support for relocations in other sections as needed.
699    // Record relocations for the debug_info and debug_line sections.
700    RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
701        .Case("debug_info", &InfoSection.Relocs)
702        .Case("debug_loc", &LocSection.Relocs)
703        .Case("debug_info.dwo", &InfoDWOSection.Relocs)
704        .Case("debug_line", &LineSection.Relocs)
705        .Default(nullptr);
706    if (!Map) {
707      // Find debug_types relocs by section rather than name as there are
708      // multiple, comdat grouped, debug_types sections.
709      if (RelSecName == "debug_types")
710        Map = &TypesSections[*RelocatedSection].Relocs;
711      else if (RelSecName == "debug_types.dwo")
712        Map = &TypesDWOSections[*RelocatedSection].Relocs;
713      else
714        continue;
715    }
716
717    if (Section.relocation_begin() != Section.relocation_end()) {
718      uint64_t SectionSize;
719      RelocatedSection->getSize(SectionSize);
720      for (const RelocationRef &Reloc : Section.relocations()) {
721        uint64_t Address;
722        Reloc.getOffset(Address);
723        uint64_t Type;
724        Reloc.getType(Type);
725        uint64_t SymAddr = 0;
726        // ELF relocations may need the symbol address
727        if (Obj->isELF()) {
728          object::symbol_iterator Sym = Reloc.getSymbol();
729          Sym->getAddress(SymAddr);
730        }
731
732        object::RelocVisitor V(Obj->getFileFormatName());
733        // The section address is always 0 for debug sections.
734        object::RelocToApply R(V.visit(Type, Reloc, 0, SymAddr));
735        if (V.error()) {
736          SmallString<32> Name;
737          error_code ec(Reloc.getTypeName(Name));
738          if (ec) {
739            errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n";
740          }
741          errs() << "error: failed to compute relocation: "
742                 << Name << "\n";
743          continue;
744        }
745
746        if (Address + R.Width > SectionSize) {
747          errs() << "error: " << R.Width << "-byte relocation starting "
748                 << Address << " bytes into section " << name << " which is "
749                 << SectionSize << " bytes long.\n";
750          continue;
751        }
752        if (R.Width > 8) {
753          errs() << "error: can't handle a relocation of more than 8 bytes at "
754                    "a time.\n";
755          continue;
756        }
757        DEBUG(dbgs() << "Writing " << format("%p", R.Value)
758                     << " at " << format("%p", Address)
759                     << " with width " << format("%d", R.Width)
760                     << "\n");
761        Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
762      }
763    }
764  }
765}
766
767void DWARFContextInMemory::anchor() { }
768