lib/ObjectYAML/DWARFEmitter.cpp

   1 //===- DWARFEmitter - Convert YAML to DWARF binary data -------------------===//
   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 /// \file
  11 /// \brief The DWARF component of yaml2obj. Provided as library code for tests.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/ObjectYAML/DWARFEmitter.h"
  16 #include "DWARFVisitor.h"
  17 #include "llvm/ADT/StringMap.h"
  18 #include "llvm/ADT/StringRef.h"
  19 #include "llvm/ObjectYAML/DWARFYAML.h"
  20 #include "llvm/Support/Error.h"
  21 #include "llvm/Support/Host.h"
  22 #include "llvm/Support/LEB128.h"
  23 #include "llvm/Support/MathExtras.h"
  24 #include "llvm/Support/MemoryBuffer.h"
  25 #include "llvm/Support/SwapByteOrder.h"
  26 #include "llvm/Support/YAMLTraits.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include <algorithm>
  29 #include <cassert>
  30 #include <cstddef>
  31 #include <cstdint>
  32 #include <memory>
  33 #include <string>
  34 #include <vector>
  35
  36 using namespace llvm;
  37
  38 template <typename T>
  39 static void writeInteger(T Integer, raw_ostream &OS, bool IsLittleEndian) {
  40   if (IsLittleEndian != sys::IsLittleEndianHost)
  41     sys::swapByteOrder(Integer);
  42   OS.write(reinterpret_cast<char *>(&Integer), sizeof(T));
  43 }
  44
  45 static void writeVariableSizedInteger(uint64_t Integer, size_t Size,
  46                                       raw_ostream &OS, bool IsLittleEndian) {
  47   if (8 == Size)
  48     writeInteger((uint64_t)Integer, OS, IsLittleEndian);
  49   else if (4 == Size)
  50     writeInteger((uint32_t)Integer, OS, IsLittleEndian);
  51   else if (2 == Size)
  52     writeInteger((uint16_t)Integer, OS, IsLittleEndian);
  53   else if (1 == Size)
  54     writeInteger((uint8_t)Integer, OS, IsLittleEndian);
  55   else
  56     assert(false && "Invalid integer write size.");
  57 }
  58
  59 static void ZeroFillBytes(raw_ostream &OS, size_t Size) {
  60   std::vector<uint8_t> FillData;
  61   FillData.insert(FillData.begin(), Size, 0);
  62   OS.write(reinterpret_cast<char *>(FillData.data()), Size);
  63 }
  64
  65 static void writeInitialLength(const DWARFYAML::InitialLength &Length,
  66                                raw_ostream &OS, bool IsLittleEndian) {
  67   writeInteger((uint32_t)Length.TotalLength, OS, IsLittleEndian);
  68   if (Length.isDWARF64())
  69     writeInteger((uint64_t)Length.TotalLength64, OS, IsLittleEndian);
  70 }
  71
  72 void DWARFYAML::EmitDebugStr(raw_ostream &OS, const DWARFYAML::Data &DI) {
  73   for (auto Str : DI.DebugStrings) {
  74     OS.write(Str.data(), Str.size());
  75     OS.write('\0');
  76   }
  77 }
  78
  79 void DWARFYAML::EmitDebugAbbrev(raw_ostream &OS, const DWARFYAML::Data &DI) {
  80   for (auto AbbrevDecl : DI.AbbrevDecls) {
  81     encodeULEB128(AbbrevDecl.Code, OS);
  82     encodeULEB128(AbbrevDecl.Tag, OS);
  83     OS.write(AbbrevDecl.Children);
  84     for (auto Attr : AbbrevDecl.Attributes) {
  85       encodeULEB128(Attr.Attribute, OS);
  86       encodeULEB128(Attr.Form, OS);
  87       if (Attr.Form == dwarf::DW_FORM_implicit_const)
  88         encodeSLEB128(Attr.Value, OS);
  89     }
  90     encodeULEB128(0, OS);
  91     encodeULEB128(0, OS);
  92   }
  93 }
  94
  95 void DWARFYAML::EmitDebugAranges(raw_ostream &OS, const DWARFYAML::Data &DI) {
  96   for (auto Range : DI.ARanges) {
  97     auto HeaderStart = OS.tell();
  98     writeInitialLength(Range.Length, OS, DI.IsLittleEndian);
  99     writeInteger((uint16_t)Range.Version, OS, DI.IsLittleEndian);
 100     writeInteger((uint32_t)Range.CuOffset, OS, DI.IsLittleEndian);
 101     writeInteger((uint8_t)Range.AddrSize, OS, DI.IsLittleEndian);
 102     writeInteger((uint8_t)Range.SegSize, OS, DI.IsLittleEndian);
 103
 104     auto HeaderSize = OS.tell() - HeaderStart;
 105     auto FirstDescriptor = alignTo(HeaderSize, Range.AddrSize * 2);
 106     ZeroFillBytes(OS, FirstDescriptor - HeaderSize);
 107
 108     for (auto Descriptor : Range.Descriptors) {
 109       writeVariableSizedInteger(Descriptor.Address, Range.AddrSize, OS,
 110                                 DI.IsLittleEndian);
 111       writeVariableSizedInteger(Descriptor.Length, Range.AddrSize, OS,
 112                                 DI.IsLittleEndian);
 113     }
 114     ZeroFillBytes(OS, Range.AddrSize * 2);
 115   }
 116 }
 117
 118 void DWARFYAML::EmitPubSection(raw_ostream &OS,
 119                                const DWARFYAML::PubSection &Sect,
 120                                bool IsLittleEndian) {
 121   writeInitialLength(Sect.Length, OS, IsLittleEndian);
 122   writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian);
 123   writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian);
 124   writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian);
 125   for (auto Entry : Sect.Entries) {
 126     writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian);
 127     if (Sect.IsGNUStyle)
 128       writeInteger((uint32_t)Entry.Descriptor, OS, IsLittleEndian);
 129     OS.write(Entry.Name.data(), Entry.Name.size());
 130     OS.write('\0');
 131   }
 132 }
 133
 134 namespace {
 135 /// \brief An extension of the DWARFYAML::ConstVisitor which writes compile
 136 /// units and DIEs to a stream.
 137 class DumpVisitor : public DWARFYAML::ConstVisitor {
 138   raw_ostream &OS;
 139
 140 protected:
 141   void onStartCompileUnit(const DWARFYAML::Unit &CU) override {
 142     writeInitialLength(CU.Length, OS, DebugInfo.IsLittleEndian);
 143     writeInteger((uint16_t)CU.Version, OS, DebugInfo.IsLittleEndian);
 144     if(CU.Version >= 5) {
 145       writeInteger((uint8_t)CU.Type, OS, DebugInfo.IsLittleEndian);
 146       writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
 147       writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
 148     }else {
 149       writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
 150       writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
 151     }
 152
 153   }
 154
 155   void onStartDIE(const DWARFYAML::Unit &CU,
 156                   const DWARFYAML::Entry &DIE) override {
 157     encodeULEB128(DIE.AbbrCode, OS);
 158   }
 159
 160   void onValue(const uint8_t U) override {
 161     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 162   }
 163
 164   void onValue(const uint16_t U) override {
 165     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 166   }
 167
 168   void onValue(const uint32_t U) override {
 169     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 170   }
 171
 172   void onValue(const uint64_t U, const bool LEB = false) override {
 173     if (LEB)
 174       encodeULEB128(U, OS);
 175     else
 176       writeInteger(U, OS, DebugInfo.IsLittleEndian);
 177   }
 178
 179   void onValue(const int64_t S, const bool LEB = false) override {
 180     if (LEB)
 181       encodeSLEB128(S, OS);
 182     else
 183       writeInteger(S, OS, DebugInfo.IsLittleEndian);
 184   }
 185
 186   void onValue(const StringRef String) override {
 187     OS.write(String.data(), String.size());
 188     OS.write('\0');
 189   }
 190
 191   void onValue(const MemoryBufferRef MBR) override {
 192     OS.write(MBR.getBufferStart(), MBR.getBufferSize());
 193   }
 194
 195 public:
 196   DumpVisitor(const DWARFYAML::Data &DI, raw_ostream &Out)
 197       : DWARFYAML::ConstVisitor(DI), OS(Out) {}
 198 };
 199 } // namespace
 200
 201 void DWARFYAML::EmitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) {
 202   DumpVisitor Visitor(DI, OS);
 203   Visitor.traverseDebugInfo();
 204 }
 205
 206 static void EmitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) {
 207   OS.write(File.Name.data(), File.Name.size());
 208   OS.write('\0');
 209   encodeULEB128(File.DirIdx, OS);
 210   encodeULEB128(File.ModTime, OS);
 211   encodeULEB128(File.Length, OS);
 212 }
 213
 214 void DWARFYAML::EmitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
 215   for (const auto &LineTable : DI.DebugLines) {
 216     writeInitialLength(LineTable.Length, OS, DI.IsLittleEndian);
 217     uint64_t SizeOfPrologueLength = LineTable.Length.isDWARF64() ? 8 : 4;
 218     writeInteger((uint16_t)LineTable.Version, OS, DI.IsLittleEndian);
 219     writeVariableSizedInteger(LineTable.PrologueLength, SizeOfPrologueLength,
 220                               OS, DI.IsLittleEndian);
 221     writeInteger((uint8_t)LineTable.MinInstLength, OS, DI.IsLittleEndian);
 222     if (LineTable.Version >= 4)
 223       writeInteger((uint8_t)LineTable.MaxOpsPerInst, OS, DI.IsLittleEndian);
 224     writeInteger((uint8_t)LineTable.DefaultIsStmt, OS, DI.IsLittleEndian);
 225     writeInteger((uint8_t)LineTable.LineBase, OS, DI.IsLittleEndian);
 226     writeInteger((uint8_t)LineTable.LineRange, OS, DI.IsLittleEndian);
 227     writeInteger((uint8_t)LineTable.OpcodeBase, OS, DI.IsLittleEndian);
 228
 229     for (auto OpcodeLength : LineTable.StandardOpcodeLengths)
 230       writeInteger((uint8_t)OpcodeLength, OS, DI.IsLittleEndian);
 231
 232     for (auto IncludeDir : LineTable.IncludeDirs) {
 233       OS.write(IncludeDir.data(), IncludeDir.size());
 234       OS.write('\0');
 235     }
 236     OS.write('\0');
 237
 238     for (auto File : LineTable.Files)
 239       EmitFileEntry(OS, File);
 240     OS.write('\0');
 241
 242     for (auto Op : LineTable.Opcodes) {
 243       writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian);
 244       if (Op.Opcode == 0) {
 245         encodeULEB128(Op.ExtLen, OS);
 246         writeInteger((uint8_t)Op.SubOpcode, OS, DI.IsLittleEndian);
 247         switch (Op.SubOpcode) {
 248         case dwarf::DW_LNE_set_address:
 249         case dwarf::DW_LNE_set_discriminator:
 250           writeVariableSizedInteger(Op.Data, DI.CompileUnits[0].AddrSize, OS,
 251                                     DI.IsLittleEndian);
 252           break;
 253         case dwarf::DW_LNE_define_file:
 254           EmitFileEntry(OS, Op.FileEntry);
 255           break;
 256         case dwarf::DW_LNE_end_sequence:
 257           break;
 258         default:
 259           for (auto OpByte : Op.UnknownOpcodeData)
 260             writeInteger((uint8_t)OpByte, OS, DI.IsLittleEndian);
 261         }
 262       } else if (Op.Opcode < LineTable.OpcodeBase) {
 263         switch (Op.Opcode) {
 264         case dwarf::DW_LNS_copy:
 265         case dwarf::DW_LNS_negate_stmt:
 266         case dwarf::DW_LNS_set_basic_block:
 267         case dwarf::DW_LNS_const_add_pc:
 268         case dwarf::DW_LNS_set_prologue_end:
 269         case dwarf::DW_LNS_set_epilogue_begin:
 270           break;
 271
 272         case dwarf::DW_LNS_advance_pc:
 273         case dwarf::DW_LNS_set_file:
 274         case dwarf::DW_LNS_set_column:
 275         case dwarf::DW_LNS_set_isa:
 276           encodeULEB128(Op.Data, OS);
 277           break;
 278
 279         case dwarf::DW_LNS_advance_line:
 280           encodeSLEB128(Op.SData, OS);
 281           break;
 282
 283         case dwarf::DW_LNS_fixed_advance_pc:
 284           writeInteger((uint16_t)Op.Data, OS, DI.IsLittleEndian);
 285           break;
 286
 287         default:
 288           for (auto OpData : Op.StandardOpcodeData) {
 289             encodeULEB128(OpData, OS);
 290           }
 291         }
 292       }
 293     }
 294   }
 295 }
 296
 297 using EmitFuncType = void (*)(raw_ostream &, const DWARFYAML::Data &);
 298
 299 static void
 300 EmitDebugSectionImpl(const DWARFYAML::Data &DI, EmitFuncType EmitFunc,
 301                      StringRef Sec,
 302                      StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) {
 303   std::string Data;
 304   raw_string_ostream DebugInfoStream(Data);
 305   EmitFunc(DebugInfoStream, DI);
 306   DebugInfoStream.flush();
 307   if (!Data.empty())
 308     OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
 309 }
 310
 311 Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
 312 DWARFYAML::EmitDebugSections(StringRef YAMLString,
 313                              bool IsLittleEndian) {
 314   StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;
 315
 316   yaml::Input YIn(YAMLString);
 317
 318   DWARFYAML::Data DI;
 319   DI.IsLittleEndian = IsLittleEndian;
 320   YIn >> DI;
 321   if (YIn.error())
 322     return errorCodeToError(YIn.error());
 323
 324   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugInfo, "debug_info",
 325                        DebugSections);
 326   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugLine, "debug_line",
 327                        DebugSections);
 328   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugStr, "debug_str",
 329                        DebugSections);
 330   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAbbrev, "debug_abbrev",
 331                        DebugSections);
 332   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAranges, "debug_aranges",
 333                        DebugSections);
 334   return std::move(DebugSections);
 335 }