lib/ObjectYAML/DWARFEmitter.cpp

   1 //===- DWARFEmitter - Convert YAML to DWARF binary data -------------------===//
   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 /// \file
  10 /// The DWARF component of yaml2obj. Provided as library code for tests.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ObjectYAML/DWARFEmitter.h"
  15 #include "DWARFVisitor.h"
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/ObjectYAML/DWARFYAML.h"
  19 #include "llvm/Support/Error.h"
  20 #include "llvm/Support/Host.h"
  21 #include "llvm/Support/LEB128.h"
  22 #include "llvm/Support/MathExtras.h"
  23 #include "llvm/Support/MemoryBuffer.h"
  24 #include "llvm/Support/SwapByteOrder.h"
  25 #include "llvm/Support/YAMLTraits.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <algorithm>
  28 #include <cassert>
  29 #include <cstddef>
  30 #include <cstdint>
  31 #include <memory>
  32 #include <string>
  33 #include <vector>
  34
  35 using namespace llvm;
  36
  37 template <typename T>
  38 static void writeInteger(T Integer, raw_ostream &OS, bool IsLittleEndian) {
  39   if (IsLittleEndian != sys::IsLittleEndianHost)
  40     sys::swapByteOrder(Integer);
  41   OS.write(reinterpret_cast<char *>(&Integer), sizeof(T));
  42 }
  43
  44 static void writeVariableSizedInteger(uint64_t Integer, size_t Size,
  45                                       raw_ostream &OS, bool IsLittleEndian) {
  46   if (8 == Size)
  47     writeInteger((uint64_t)Integer, OS, IsLittleEndian);
  48   else if (4 == Size)
  49     writeInteger((uint32_t)Integer, OS, IsLittleEndian);
  50   else if (2 == Size)
  51     writeInteger((uint16_t)Integer, OS, IsLittleEndian);
  52   else if (1 == Size)
  53     writeInteger((uint8_t)Integer, OS, IsLittleEndian);
  54   else
  55     assert(false && "Invalid integer write size.");
  56 }
  57
  58 static void ZeroFillBytes(raw_ostream &OS, size_t Size) {
  59   std::vector<uint8_t> FillData;
  60   FillData.insert(FillData.begin(), Size, 0);
  61   OS.write(reinterpret_cast<char *>(FillData.data()), Size);
  62 }
  63
  64 static void writeInitialLength(const DWARFYAML::InitialLength &Length,
  65                                raw_ostream &OS, bool IsLittleEndian) {
  66   writeInteger((uint32_t)Length.TotalLength, OS, IsLittleEndian);
  67   if (Length.isDWARF64())
  68     writeInteger((uint64_t)Length.TotalLength64, OS, IsLittleEndian);
  69 }
  70
  71 void DWARFYAML::EmitDebugStr(raw_ostream &OS, const DWARFYAML::Data &DI) {
  72   for (auto Str : DI.DebugStrings) {
  73     OS.write(Str.data(), Str.size());
  74     OS.write('\0');
  75   }
  76 }
  77
  78 void DWARFYAML::EmitDebugAbbrev(raw_ostream &OS, const DWARFYAML::Data &DI) {
  79   for (auto AbbrevDecl : DI.AbbrevDecls) {
  80     encodeULEB128(AbbrevDecl.Code, OS);
  81     encodeULEB128(AbbrevDecl.Tag, OS);
  82     OS.write(AbbrevDecl.Children);
  83     for (auto Attr : AbbrevDecl.Attributes) {
  84       encodeULEB128(Attr.Attribute, OS);
  85       encodeULEB128(Attr.Form, OS);
  86       if (Attr.Form == dwarf::DW_FORM_implicit_const)
  87         encodeSLEB128(Attr.Value, OS);
  88     }
  89     encodeULEB128(0, OS);
  90     encodeULEB128(0, OS);
  91   }
  92 }
  93
  94 void DWARFYAML::EmitDebugAranges(raw_ostream &OS, const DWARFYAML::Data &DI) {
  95   for (auto Range : DI.ARanges) {
  96     auto HeaderStart = OS.tell();
  97     writeInitialLength(Range.Length, OS, DI.IsLittleEndian);
  98     writeInteger((uint16_t)Range.Version, OS, DI.IsLittleEndian);
  99     writeInteger((uint32_t)Range.CuOffset, OS, DI.IsLittleEndian);
 100     writeInteger((uint8_t)Range.AddrSize, OS, DI.IsLittleEndian);
 101     writeInteger((uint8_t)Range.SegSize, OS, DI.IsLittleEndian);
 102
 103     auto HeaderSize = OS.tell() - HeaderStart;
 104     auto FirstDescriptor = alignTo(HeaderSize, Range.AddrSize * 2);
 105     ZeroFillBytes(OS, FirstDescriptor - HeaderSize);
 106
 107     for (auto Descriptor : Range.Descriptors) {
 108       writeVariableSizedInteger(Descriptor.Address, Range.AddrSize, OS,
 109                                 DI.IsLittleEndian);
 110       writeVariableSizedInteger(Descriptor.Length, Range.AddrSize, OS,
 111                                 DI.IsLittleEndian);
 112     }
 113     ZeroFillBytes(OS, Range.AddrSize * 2);
 114   }
 115 }
 116
 117 void DWARFYAML::EmitPubSection(raw_ostream &OS,
 118                                const DWARFYAML::PubSection &Sect,
 119                                bool IsLittleEndian) {
 120   writeInitialLength(Sect.Length, OS, IsLittleEndian);
 121   writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian);
 122   writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian);
 123   writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian);
 124   for (auto Entry : Sect.Entries) {
 125     writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian);
 126     if (Sect.IsGNUStyle)
 127       writeInteger((uint32_t)Entry.Descriptor, OS, IsLittleEndian);
 128     OS.write(Entry.Name.data(), Entry.Name.size());
 129     OS.write('\0');
 130   }
 131 }
 132
 133 namespace {
 134 /// An extension of the DWARFYAML::ConstVisitor which writes compile
 135 /// units and DIEs to a stream.
 136 class DumpVisitor : public DWARFYAML::ConstVisitor {
 137   raw_ostream &OS;
 138
 139 protected:
 140   void onStartCompileUnit(const DWARFYAML::Unit &CU) override {
 141     writeInitialLength(CU.Length, OS, DebugInfo.IsLittleEndian);
 142     writeInteger((uint16_t)CU.Version, OS, DebugInfo.IsLittleEndian);
 143     if(CU.Version >= 5) {
 144       writeInteger((uint8_t)CU.Type, OS, DebugInfo.IsLittleEndian);
 145       writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
 146       writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
 147     }else {
 148       writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
 149       writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
 150     }
 151   }
 152
 153   void onStartDIE(const DWARFYAML::Unit &CU,
 154                   const DWARFYAML::Entry &DIE) override {
 155     encodeULEB128(DIE.AbbrCode, OS);
 156   }
 157
 158   void onValue(const uint8_t U) override {
 159     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 160   }
 161
 162   void onValue(const uint16_t U) override {
 163     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 164   }
 165
 166   void onValue(const uint32_t U) override {
 167     writeInteger(U, OS, DebugInfo.IsLittleEndian);
 168   }
 169
 170   void onValue(const uint64_t U, const bool LEB = false) override {
 171     if (LEB)
 172       encodeULEB128(U, OS);
 173     else
 174       writeInteger(U, OS, DebugInfo.IsLittleEndian);
 175   }
 176
 177   void onValue(const int64_t S, const bool LEB = false) override {
 178     if (LEB)
 179       encodeSLEB128(S, OS);
 180     else
 181       writeInteger(S, OS, DebugInfo.IsLittleEndian);
 182   }
 183
 184   void onValue(const StringRef String) override {
 185     OS.write(String.data(), String.size());
 186     OS.write('\0');
 187   }
 188
 189   void onValue(const MemoryBufferRef MBR) override {
 190     OS.write(MBR.getBufferStart(), MBR.getBufferSize());
 191   }
 192
 193 public:
 194   DumpVisitor(const DWARFYAML::Data &DI, raw_ostream &Out)
 195       : DWARFYAML::ConstVisitor(DI), OS(Out) {}
 196 };
 197 } // namespace
 198
 199 void DWARFYAML::EmitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) {
 200   DumpVisitor Visitor(DI, OS);
 201   Visitor.traverseDebugInfo();
 202 }
 203
 204 static void EmitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) {
 205   OS.write(File.Name.data(), File.Name.size());
 206   OS.write('\0');
 207   encodeULEB128(File.DirIdx, OS);
 208   encodeULEB128(File.ModTime, OS);
 209   encodeULEB128(File.Length, OS);
 210 }
 211
 212 void DWARFYAML::EmitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
 213   for (const auto &LineTable : DI.DebugLines) {
 214     writeInitialLength(LineTable.Length, OS, DI.IsLittleEndian);
 215     uint64_t SizeOfPrologueLength = LineTable.Length.isDWARF64() ? 8 : 4;
 216     writeInteger((uint16_t)LineTable.Version, OS, DI.IsLittleEndian);
 217     writeVariableSizedInteger(LineTable.PrologueLength, SizeOfPrologueLength,
 218                               OS, DI.IsLittleEndian);
 219     writeInteger((uint8_t)LineTable.MinInstLength, OS, DI.IsLittleEndian);
 220     if (LineTable.Version >= 4)
 221       writeInteger((uint8_t)LineTable.MaxOpsPerInst, OS, DI.IsLittleEndian);
 222     writeInteger((uint8_t)LineTable.DefaultIsStmt, OS, DI.IsLittleEndian);
 223     writeInteger((uint8_t)LineTable.LineBase, OS, DI.IsLittleEndian);
 224     writeInteger((uint8_t)LineTable.LineRange, OS, DI.IsLittleEndian);
 225     writeInteger((uint8_t)LineTable.OpcodeBase, OS, DI.IsLittleEndian);
 226
 227     for (auto OpcodeLength : LineTable.StandardOpcodeLengths)
 228       writeInteger((uint8_t)OpcodeLength, OS, DI.IsLittleEndian);
 229
 230     for (auto IncludeDir : LineTable.IncludeDirs) {
 231       OS.write(IncludeDir.data(), IncludeDir.size());
 232       OS.write('\0');
 233     }
 234     OS.write('\0');
 235
 236     for (auto File : LineTable.Files)
 237       EmitFileEntry(OS, File);
 238     OS.write('\0');
 239
 240     for (auto Op : LineTable.Opcodes) {
 241       writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian);
 242       if (Op.Opcode == 0) {
 243         encodeULEB128(Op.ExtLen, OS);
 244         writeInteger((uint8_t)Op.SubOpcode, OS, DI.IsLittleEndian);
 245         switch (Op.SubOpcode) {
 246         case dwarf::DW_LNE_set_address:
 247         case dwarf::DW_LNE_set_discriminator:
 248           writeVariableSizedInteger(Op.Data, DI.CompileUnits[0].AddrSize, OS,
 249                                     DI.IsLittleEndian);
 250           break;
 251         case dwarf::DW_LNE_define_file:
 252           EmitFileEntry(OS, Op.FileEntry);
 253           break;
 254         case dwarf::DW_LNE_end_sequence:
 255           break;
 256         default:
 257           for (auto OpByte : Op.UnknownOpcodeData)
 258             writeInteger((uint8_t)OpByte, OS, DI.IsLittleEndian);
 259         }
 260       } else if (Op.Opcode < LineTable.OpcodeBase) {
 261         switch (Op.Opcode) {
 262         case dwarf::DW_LNS_copy:
 263         case dwarf::DW_LNS_negate_stmt:
 264         case dwarf::DW_LNS_set_basic_block:
 265         case dwarf::DW_LNS_const_add_pc:
 266         case dwarf::DW_LNS_set_prologue_end:
 267         case dwarf::DW_LNS_set_epilogue_begin:
 268           break;
 269
 270         case dwarf::DW_LNS_advance_pc:
 271         case dwarf::DW_LNS_set_file:
 272         case dwarf::DW_LNS_set_column:
 273         case dwarf::DW_LNS_set_isa:
 274           encodeULEB128(Op.Data, OS);
 275           break;
 276
 277         case dwarf::DW_LNS_advance_line:
 278           encodeSLEB128(Op.SData, OS);
 279           break;
 280
 281         case dwarf::DW_LNS_fixed_advance_pc:
 282           writeInteger((uint16_t)Op.Data, OS, DI.IsLittleEndian);
 283           break;
 284
 285         default:
 286           for (auto OpData : Op.StandardOpcodeData) {
 287             encodeULEB128(OpData, OS);
 288           }
 289         }
 290       }
 291     }
 292   }
 293 }
 294
 295 using EmitFuncType = void (*)(raw_ostream &, const DWARFYAML::Data &);
 296
 297 static void
 298 EmitDebugSectionImpl(const DWARFYAML::Data &DI, EmitFuncType EmitFunc,
 299                      StringRef Sec,
 300                      StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) {
 301   std::string Data;
 302   raw_string_ostream DebugInfoStream(Data);
 303   EmitFunc(DebugInfoStream, DI);
 304   DebugInfoStream.flush();
 305   if (!Data.empty())
 306     OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
 307 }
 308
 309 namespace {
 310 class DIEFixupVisitor : public DWARFYAML::Visitor {
 311   uint64_t Length;
 312
 313 public:
 314   DIEFixupVisitor(DWARFYAML::Data &DI) : DWARFYAML::Visitor(DI){};
 315
 316 private:
 317   virtual void onStartCompileUnit(DWARFYAML::Unit &CU) { Length = 7; }
 318
 319   virtual void onEndCompileUnit(DWARFYAML::Unit &CU) {
 320     CU.Length.setLength(Length);
 321   }
 322
 323   virtual void onStartDIE(DWARFYAML::Unit &CU, DWARFYAML::Entry &DIE) {
 324     Length += getULEB128Size(DIE.AbbrCode);
 325   }
 326
 327   virtual void onValue(const uint8_t U) { Length += 1; }
 328   virtual void onValue(const uint16_t U) { Length += 2; }
 329   virtual void onValue(const uint32_t U) { Length += 4; }
 330   virtual void onValue(const uint64_t U, const bool LEB = false) {
 331     if (LEB)
 332       Length += getULEB128Size(U);
 333     else
 334       Length += 8;
 335   }
 336   virtual void onValue(const int64_t S, const bool LEB = false) {
 337     if (LEB)
 338       Length += getSLEB128Size(S);
 339     else
 340       Length += 8;
 341   }
 342   virtual void onValue(const StringRef String) { Length += String.size() + 1; }
 343
 344   virtual void onValue(const MemoryBufferRef MBR) {
 345     Length += MBR.getBufferSize();
 346   }
 347 };
 348 } // namespace
 349
 350 Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
 351 DWARFYAML::EmitDebugSections(StringRef YAMLString, bool ApplyFixups,
 352                              bool IsLittleEndian) {
 353   yaml::Input YIn(YAMLString);
 354
 355   DWARFYAML::Data DI;
 356   DI.IsLittleEndian = IsLittleEndian;
 357   YIn >> DI;
 358   if (YIn.error())
 359     return errorCodeToError(YIn.error());
 360
 361   if (ApplyFixups) {
 362     DIEFixupVisitor DIFixer(DI);
 363     DIFixer.traverseDebugInfo();
 364   }
 365
 366   StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;
 367   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugInfo, "debug_info",
 368                        DebugSections);
 369   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugLine, "debug_line",
 370                        DebugSections);
 371   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugStr, "debug_str",
 372                        DebugSections);
 373   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAbbrev, "debug_abbrev",
 374                        DebugSections);
 375   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAranges, "debug_aranges",
 376                        DebugSections);
 377   return std::move(DebugSections);
 378 }