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 /// 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 /// 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   void onStartDIE(const DWARFYAML::Unit &CU,
155                   const DWARFYAML::Entry &DIE) override {
156     encodeULEB128(DIE.AbbrCode, OS);
157   }
158 
159   void onValue(const uint8_t U) override {
160     writeInteger(U, OS, DebugInfo.IsLittleEndian);
161   }
162 
163   void onValue(const uint16_t U) override {
164     writeInteger(U, OS, DebugInfo.IsLittleEndian);
165   }
166 
167   void onValue(const uint32_t U) override {
168     writeInteger(U, OS, DebugInfo.IsLittleEndian);
169   }
170 
171   void onValue(const uint64_t U, const bool LEB = false) override {
172     if (LEB)
173       encodeULEB128(U, OS);
174     else
175       writeInteger(U, OS, DebugInfo.IsLittleEndian);
176   }
177 
178   void onValue(const int64_t S, const bool LEB = false) override {
179     if (LEB)
180       encodeSLEB128(S, OS);
181     else
182       writeInteger(S, OS, DebugInfo.IsLittleEndian);
183   }
184 
185   void onValue(const StringRef String) override {
186     OS.write(String.data(), String.size());
187     OS.write('\0');
188   }
189 
190   void onValue(const MemoryBufferRef MBR) override {
191     OS.write(MBR.getBufferStart(), MBR.getBufferSize());
192   }
193 
194 public:
195   DumpVisitor(const DWARFYAML::Data &DI, raw_ostream &Out)
196       : DWARFYAML::ConstVisitor(DI), OS(Out) {}
197 };
198 } // namespace
199 
200 void DWARFYAML::EmitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) {
201   DumpVisitor Visitor(DI, OS);
202   Visitor.traverseDebugInfo();
203 }
204 
205 static void EmitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) {
206   OS.write(File.Name.data(), File.Name.size());
207   OS.write('\0');
208   encodeULEB128(File.DirIdx, OS);
209   encodeULEB128(File.ModTime, OS);
210   encodeULEB128(File.Length, OS);
211 }
212 
213 void DWARFYAML::EmitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
214   for (const auto &LineTable : DI.DebugLines) {
215     writeInitialLength(LineTable.Length, OS, DI.IsLittleEndian);
216     uint64_t SizeOfPrologueLength = LineTable.Length.isDWARF64() ? 8 : 4;
217     writeInteger((uint16_t)LineTable.Version, OS, DI.IsLittleEndian);
218     writeVariableSizedInteger(LineTable.PrologueLength, SizeOfPrologueLength,
219                               OS, DI.IsLittleEndian);
220     writeInteger((uint8_t)LineTable.MinInstLength, OS, DI.IsLittleEndian);
221     if (LineTable.Version >= 4)
222       writeInteger((uint8_t)LineTable.MaxOpsPerInst, OS, DI.IsLittleEndian);
223     writeInteger((uint8_t)LineTable.DefaultIsStmt, OS, DI.IsLittleEndian);
224     writeInteger((uint8_t)LineTable.LineBase, OS, DI.IsLittleEndian);
225     writeInteger((uint8_t)LineTable.LineRange, OS, DI.IsLittleEndian);
226     writeInteger((uint8_t)LineTable.OpcodeBase, OS, DI.IsLittleEndian);
227 
228     for (auto OpcodeLength : LineTable.StandardOpcodeLengths)
229       writeInteger((uint8_t)OpcodeLength, OS, DI.IsLittleEndian);
230 
231     for (auto IncludeDir : LineTable.IncludeDirs) {
232       OS.write(IncludeDir.data(), IncludeDir.size());
233       OS.write('\0');
234     }
235     OS.write('\0');
236 
237     for (auto File : LineTable.Files)
238       EmitFileEntry(OS, File);
239     OS.write('\0');
240 
241     for (auto Op : LineTable.Opcodes) {
242       writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian);
243       if (Op.Opcode == 0) {
244         encodeULEB128(Op.ExtLen, OS);
245         writeInteger((uint8_t)Op.SubOpcode, OS, DI.IsLittleEndian);
246         switch (Op.SubOpcode) {
247         case dwarf::DW_LNE_set_address:
248         case dwarf::DW_LNE_set_discriminator:
249           writeVariableSizedInteger(Op.Data, DI.CompileUnits[0].AddrSize, OS,
250                                     DI.IsLittleEndian);
251           break;
252         case dwarf::DW_LNE_define_file:
253           EmitFileEntry(OS, Op.FileEntry);
254           break;
255         case dwarf::DW_LNE_end_sequence:
256           break;
257         default:
258           for (auto OpByte : Op.UnknownOpcodeData)
259             writeInteger((uint8_t)OpByte, OS, DI.IsLittleEndian);
260         }
261       } else if (Op.Opcode < LineTable.OpcodeBase) {
262         switch (Op.Opcode) {
263         case dwarf::DW_LNS_copy:
264         case dwarf::DW_LNS_negate_stmt:
265         case dwarf::DW_LNS_set_basic_block:
266         case dwarf::DW_LNS_const_add_pc:
267         case dwarf::DW_LNS_set_prologue_end:
268         case dwarf::DW_LNS_set_epilogue_begin:
269           break;
270 
271         case dwarf::DW_LNS_advance_pc:
272         case dwarf::DW_LNS_set_file:
273         case dwarf::DW_LNS_set_column:
274         case dwarf::DW_LNS_set_isa:
275           encodeULEB128(Op.Data, OS);
276           break;
277 
278         case dwarf::DW_LNS_advance_line:
279           encodeSLEB128(Op.SData, OS);
280           break;
281 
282         case dwarf::DW_LNS_fixed_advance_pc:
283           writeInteger((uint16_t)Op.Data, OS, DI.IsLittleEndian);
284           break;
285 
286         default:
287           for (auto OpData : Op.StandardOpcodeData) {
288             encodeULEB128(OpData, OS);
289           }
290         }
291       }
292     }
293   }
294 }
295 
296 using EmitFuncType = void (*)(raw_ostream &, const DWARFYAML::Data &);
297 
298 static void
299 EmitDebugSectionImpl(const DWARFYAML::Data &DI, EmitFuncType EmitFunc,
300                      StringRef Sec,
301                      StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) {
302   std::string Data;
303   raw_string_ostream DebugInfoStream(Data);
304   EmitFunc(DebugInfoStream, DI);
305   DebugInfoStream.flush();
306   if (!Data.empty())
307     OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
308 }
309 
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 
349 Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
350 DWARFYAML::EmitDebugSections(StringRef YAMLString, bool ApplyFixups,
351                              bool IsLittleEndian) {
352   yaml::Input YIn(YAMLString);
353 
354   DWARFYAML::Data DI;
355   DI.IsLittleEndian = IsLittleEndian;
356   YIn >> DI;
357   if (YIn.error())
358     return errorCodeToError(YIn.error());
359 
360   if (ApplyFixups) {
361     DIEFixupVisitor DIFixer(DI);
362     DIFixer.traverseDebugInfo();
363   }
364 
365   StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;
366   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugInfo, "debug_info",
367                        DebugSections);
368   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugLine, "debug_line",
369                        DebugSections);
370   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugStr, "debug_str",
371                        DebugSections);
372   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAbbrev, "debug_abbrev",
373                        DebugSections);
374   EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAranges, "debug_aranges",
375                        DebugSections);
376   return std::move(DebugSections);
377 }
378