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