xref: /freebsd/contrib/llvm-project/llvm/lib/ObjectYAML/DWARFEmitter.cpp (revision f2530c80db7b29b95368fce956b3a778f096b368) 
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 }
379