llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.cpp

   1 //===- DWARFLinkerUnit.cpp ------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "DWARFLinkerUnit.h"
  10 #include "DWARFEmitterImpl.h"
  11 #include "DebugLineSectionEmitter.h"
  12
  13 namespace llvm {
  14 namespace dwarflinker_parallel {
  15
  16 void DwarfUnit::assignAbbrev(DIEAbbrev &Abbrev) {
  17   // Check the set for priors.
  18   FoldingSetNodeID ID;
  19   Abbrev.Profile(ID);
  20   void *InsertToken;
  21
  22   DIEAbbrev *InSet = AbbreviationsSet.FindNodeOrInsertPos(ID, InsertToken);
  23   // If it's newly added.
  24   if (InSet) {
  25     // Assign existing abbreviation number.
  26     Abbrev.setNumber(InSet->getNumber());
  27   } else {
  28     // Add to abbreviation list.
  29     Abbreviations.push_back(
  30         std::make_unique<DIEAbbrev>(Abbrev.getTag(), Abbrev.hasChildren()));
  31     for (const auto &Attr : Abbrev.getData())
  32       Abbreviations.back()->AddAttribute(Attr);
  33     AbbreviationsSet.InsertNode(Abbreviations.back().get(), InsertToken);
  34     // Assign the unique abbreviation number.
  35     Abbrev.setNumber(Abbreviations.size());
  36     Abbreviations.back()->setNumber(Abbreviations.size());
  37   }
  38 }
  39
  40 Error DwarfUnit::emitAbbreviations() {
  41   const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs = getAbbreviations();
  42   if (Abbrevs.empty())
  43     return Error::success();
  44
  45   SectionDescriptor &AbbrevSection =
  46       getOrCreateSectionDescriptor(DebugSectionKind::DebugAbbrev);
  47
  48   // For each abbreviation.
  49   for (const auto &Abbrev : Abbrevs)
  50     emitDwarfAbbrevEntry(*Abbrev, AbbrevSection);
  51
  52   // Mark end of abbreviations.
  53   encodeULEB128(0, AbbrevSection.OS);
  54
  55   return Error::success();
  56 }
  57
  58 void DwarfUnit::emitDwarfAbbrevEntry(const DIEAbbrev &Abbrev,
  59                                      SectionDescriptor &AbbrevSection) {
  60   // Emit the abbreviations code (base 1 index.)
  61   encodeULEB128(Abbrev.getNumber(), AbbrevSection.OS);
  62
  63   // Emit the abbreviations data.
  64   // Emit its Dwarf tag type.
  65   encodeULEB128(Abbrev.getTag(), AbbrevSection.OS);
  66
  67   // Emit whether it has children DIEs.
  68   encodeULEB128((unsigned)Abbrev.hasChildren(), AbbrevSection.OS);
  69
  70   // For each attribute description.
  71   const SmallVectorImpl<DIEAbbrevData> &Data = Abbrev.getData();
  72   for (unsigned i = 0, N = Data.size(); i < N; ++i) {
  73     const DIEAbbrevData &AttrData = Data[i];
  74
  75     // Emit attribute type.
  76     encodeULEB128(AttrData.getAttribute(), AbbrevSection.OS);
  77
  78     // Emit form type.
  79     encodeULEB128(AttrData.getForm(), AbbrevSection.OS);
  80
  81     // Emit value for DW_FORM_implicit_const.
  82     if (AttrData.getForm() == dwarf::DW_FORM_implicit_const)
  83       encodeSLEB128(AttrData.getValue(), AbbrevSection.OS);
  84   }
  85
  86   // Mark end of abbreviation.
  87   encodeULEB128(0, AbbrevSection.OS);
  88   encodeULEB128(0, AbbrevSection.OS);
  89 }
  90
  91 Error DwarfUnit::emitDebugInfo(Triple &TargetTriple) {
  92   DIE *OutUnitDIE = getOutUnitDIE();
  93   if (OutUnitDIE == nullptr)
  94     return Error::success();
  95
  96   // FIXME: Remove dependence on DwarfEmitterImpl/AsmPrinter and emit DIEs
  97   // directly.
  98
  99   SectionDescriptor &OutSection =
 100       getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
 101   DwarfEmitterImpl Emitter(DWARFLinker::OutputFileType::Object, OutSection.OS);
 102   if (Error Err = Emitter.init(TargetTriple, "__DWARF"))
 103     return Err;
 104
 105   // Emit compile unit header.
 106   Emitter.emitCompileUnitHeader(*this);
 107   size_t OffsetToAbbreviationTableOffset =
 108       (getFormParams().Version >= 5) ? 8 : 6;
 109   OutSection.notePatch(DebugOffsetPatch{
 110       OffsetToAbbreviationTableOffset,
 111       &getOrCreateSectionDescriptor(DebugSectionKind::DebugAbbrev)});
 112
 113   // Emit DIEs.
 114   Emitter.emitDIE(*OutUnitDIE);
 115   Emitter.finish();
 116
 117   // Set start offset ans size for .debug_info section.
 118   OutSection.setSizesForSectionCreatedByAsmPrinter();
 119   return Error::success();
 120 }
 121
 122 Error DwarfUnit::emitDebugLine(Triple &TargetTriple,
 123                                const DWARFDebugLine::LineTable &OutLineTable) {
 124   DebugLineSectionEmitter DebugLineEmitter(TargetTriple, *this);
 125
 126   return DebugLineEmitter.emit(OutLineTable);
 127 }
 128
 129 } // end of namespace dwarflinker_parallel
 130 } // end of namespace llvm