1 //===------ utils/elf2yaml.cpp - obj2yaml conversion tool -------*- C++ -*-===//
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 #include "Error.h"
11 #include "obj2yaml.h"
12 #include "llvm/ADT/STLExtras.h"
13 #include "llvm/Object/ELFObjectFile.h"
14 #include "llvm/Object/ELFYAML.h"
15 #include "llvm/Support/ErrorHandling.h"
16 #include "llvm/Support/YAMLTraits.h"
17 
18 using namespace llvm;
19 
20 namespace {
21 
22 template <class ELFT>
23 class ELFDumper {
24   typedef object::Elf_Sym_Impl<ELFT> Elf_Sym;
25   typedef typename object::ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
26   typedef typename object::ELFFile<ELFT>::Elf_Sym_Iter Elf_Sym_Iter;
27   typedef typename object::ELFFile<ELFT>::Elf_Word Elf_Word;
28 
29   const object::ELFFile<ELFT> &Obj;
30 
31   std::error_code dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S);
32   std::error_code dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
33   std::error_code dumpCommonRelocationSection(const Elf_Shdr *Shdr,
34                                               ELFYAML::RelocationSection &S);
35   template <class RelT>
36   std::error_code dumpRelocation(const Elf_Shdr *Shdr, const RelT *Rel,
37                                  ELFYAML::Relocation &R);
38 
39   ErrorOr<ELFYAML::RelocationSection *> dumpRelSection(const Elf_Shdr *Shdr);
40   ErrorOr<ELFYAML::RelocationSection *> dumpRelaSection(const Elf_Shdr *Shdr);
41   ErrorOr<ELFYAML::RawContentSection *>
42   dumpContentSection(const Elf_Shdr *Shdr);
43   ErrorOr<ELFYAML::Group *> dumpGroup(const Elf_Shdr *Shdr);
44   ErrorOr<ELFYAML::MipsABIFlags *> dumpMipsABIFlags(const Elf_Shdr *Shdr);
45 
46 public:
47   ELFDumper(const object::ELFFile<ELFT> &O);
48   ErrorOr<ELFYAML::Object *> dump();
49 };
50 
51 }
52 
53 template <class ELFT>
54 ELFDumper<ELFT>::ELFDumper(const object::ELFFile<ELFT> &O)
55     : Obj(O) {}
56 
57 template <class ELFT>
58 ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
59   auto Y = make_unique<ELFYAML::Object>();
60 
61   // Dump header
62   Y->Header.Class = ELFYAML::ELF_ELFCLASS(Obj.getHeader()->getFileClass());
63   Y->Header.Data = ELFYAML::ELF_ELFDATA(Obj.getHeader()->getDataEncoding());
64   Y->Header.OSABI = Obj.getHeader()->e_ident[ELF::EI_OSABI];
65   Y->Header.Type = Obj.getHeader()->e_type;
66   Y->Header.Machine = Obj.getHeader()->e_machine;
67   Y->Header.Flags = Obj.getHeader()->e_flags;
68   Y->Header.Entry = Obj.getHeader()->e_entry;
69 
70   // Dump sections
71   for (const Elf_Shdr &Sec : Obj.sections()) {
72     switch (Sec.sh_type) {
73     case ELF::SHT_NULL:
74     case ELF::SHT_SYMTAB:
75     case ELF::SHT_DYNSYM:
76     case ELF::SHT_STRTAB:
77       // Do not dump these sections.
78       break;
79     case ELF::SHT_RELA: {
80       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelaSection(&Sec);
81       if (std::error_code EC = S.getError())
82         return EC;
83       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
84       break;
85     }
86     case ELF::SHT_REL: {
87       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelSection(&Sec);
88       if (std::error_code EC = S.getError())
89         return EC;
90       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
91       break;
92     }
93     case ELF::SHT_GROUP: {
94       ErrorOr<ELFYAML::Group *> G = dumpGroup(&Sec);
95       if (std::error_code EC = G.getError())
96         return EC;
97       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(G.get()));
98       break;
99     }
100     case ELF::SHT_MIPS_ABIFLAGS: {
101       ErrorOr<ELFYAML::MipsABIFlags *> G = dumpMipsABIFlags(&Sec);
102       if (std::error_code EC = G.getError())
103         return EC;
104       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(G.get()));
105       break;
106     }
107     default: {
108       ErrorOr<ELFYAML::RawContentSection *> S = dumpContentSection(&Sec);
109       if (std::error_code EC = S.getError())
110         return EC;
111       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
112     }
113     }
114   }
115 
116   // Dump symbols
117   bool IsFirstSym = true;
118   for (auto SI = Obj.begin_symbols(), SE = Obj.end_symbols(); SI != SE; ++SI) {
119     if (IsFirstSym) {
120       IsFirstSym = false;
121       continue;
122     }
123 
124     ELFYAML::Symbol S;
125     if (std::error_code EC = ELFDumper<ELFT>::dumpSymbol(SI, S))
126       return EC;
127 
128     switch (SI->getBinding())
129     {
130     case ELF::STB_LOCAL:
131       Y->Symbols.Local.push_back(S);
132       break;
133     case ELF::STB_GLOBAL:
134       Y->Symbols.Global.push_back(S);
135       break;
136     case ELF::STB_WEAK:
137       Y->Symbols.Weak.push_back(S);
138       break;
139     default:
140       llvm_unreachable("Unknown ELF symbol binding");
141     }
142   }
143 
144   return Y.release();
145 }
146 
147 template <class ELFT>
148 std::error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym,
149                                             ELFYAML::Symbol &S) {
150   S.Type = Sym->getType();
151   S.Value = Sym->st_value;
152   S.Size = Sym->st_size;
153   S.Other = Sym->st_other;
154 
155   ErrorOr<StringRef> NameOrErr = Obj.getSymbolName(Sym);
156   if (std::error_code EC = NameOrErr.getError())
157     return EC;
158   S.Name = NameOrErr.get();
159 
160   const Elf_Shdr *Shdr = Obj.getSection(&*Sym);
161   if (!Shdr)
162     return obj2yaml_error::success;
163 
164   NameOrErr = Obj.getSectionName(Shdr);
165   if (std::error_code EC = NameOrErr.getError())
166     return EC;
167   S.Section = NameOrErr.get();
168 
169   return obj2yaml_error::success;
170 }
171 
172 template <class ELFT>
173 template <class RelT>
174 std::error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
175                                                 const RelT *Rel,
176                                                 ELFYAML::Relocation &R) {
177   R.Type = Rel->getType(Obj.isMips64EL());
178   R.Offset = Rel->r_offset;
179   R.Addend = 0;
180 
181   auto NamePair = Obj.getRelocationSymbol(Shdr, Rel);
182   if (!NamePair.first)
183     return obj2yaml_error::success;
184 
185   ErrorOr<StringRef> NameOrErr =
186       Obj.getSymbolName(NamePair.first, NamePair.second);
187   if (std::error_code EC = NameOrErr.getError())
188     return EC;
189   R.Symbol = NameOrErr.get();
190 
191   return obj2yaml_error::success;
192 }
193 
194 template <class ELFT>
195 std::error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
196                                                    ELFYAML::Section &S) {
197   S.Type = Shdr->sh_type;
198   S.Flags = Shdr->sh_flags;
199   S.Address = Shdr->sh_addr;
200   S.AddressAlign = Shdr->sh_addralign;
201 
202   ErrorOr<StringRef> NameOrErr = Obj.getSectionName(Shdr);
203   if (std::error_code EC = NameOrErr.getError())
204     return EC;
205   S.Name = NameOrErr.get();
206 
207   if (Shdr->sh_link != ELF::SHN_UNDEF) {
208     if (const Elf_Shdr *LinkSection = Obj.getSection(Shdr->sh_link)) {
209       NameOrErr = Obj.getSectionName(LinkSection);
210       if (std::error_code EC = NameOrErr.getError())
211         return EC;
212       S.Link = NameOrErr.get();
213     }
214   }
215 
216   return obj2yaml_error::success;
217 }
218 
219 template <class ELFT>
220 std::error_code
221 ELFDumper<ELFT>::dumpCommonRelocationSection(const Elf_Shdr *Shdr,
222                                              ELFYAML::RelocationSection &S) {
223   if (std::error_code EC = dumpCommonSection(Shdr, S))
224     return EC;
225 
226   if (const Elf_Shdr *InfoSection = Obj.getSection(Shdr->sh_info)) {
227     ErrorOr<StringRef> NameOrErr = Obj.getSectionName(InfoSection);
228     if (std::error_code EC = NameOrErr.getError())
229       return EC;
230     S.Info = NameOrErr.get();
231   }
232 
233   return obj2yaml_error::success;
234 }
235 
236 template <class ELFT>
237 ErrorOr<ELFYAML::RelocationSection *>
238 ELFDumper<ELFT>::dumpRelSection(const Elf_Shdr *Shdr) {
239   assert(Shdr->sh_type == ELF::SHT_REL && "Section type is not SHT_REL");
240   auto S = make_unique<ELFYAML::RelocationSection>();
241 
242   if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
243     return EC;
244 
245   for (auto RI = Obj.begin_rel(Shdr), RE = Obj.end_rel(Shdr); RI != RE;
246        ++RI) {
247     ELFYAML::Relocation R;
248     if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
249       return EC;
250     S->Relocations.push_back(R);
251   }
252 
253   return S.release();
254 }
255 
256 template <class ELFT>
257 ErrorOr<ELFYAML::RelocationSection *>
258 ELFDumper<ELFT>::dumpRelaSection(const Elf_Shdr *Shdr) {
259   assert(Shdr->sh_type == ELF::SHT_RELA && "Section type is not SHT_RELA");
260   auto S = make_unique<ELFYAML::RelocationSection>();
261 
262   if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
263     return EC;
264 
265   for (auto RI = Obj.begin_rela(Shdr), RE = Obj.end_rela(Shdr); RI != RE;
266        ++RI) {
267     ELFYAML::Relocation R;
268     if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
269       return EC;
270     R.Addend = RI->r_addend;
271     S->Relocations.push_back(R);
272   }
273 
274   return S.release();
275 }
276 
277 template <class ELFT>
278 ErrorOr<ELFYAML::RawContentSection *>
279 ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
280   auto S = make_unique<ELFYAML::RawContentSection>();
281 
282   if (std::error_code EC = dumpCommonSection(Shdr, *S))
283     return EC;
284 
285   ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
286   if (std::error_code EC = ContentOrErr.getError())
287     return EC;
288   S->Content = yaml::BinaryRef(ContentOrErr.get());
289   S->Size = S->Content.binary_size();
290 
291   return S.release();
292 }
293 
294 template <class ELFT>
295 ErrorOr<ELFYAML::Group *> ELFDumper<ELFT>::dumpGroup(const Elf_Shdr *Shdr) {
296   auto S = make_unique<ELFYAML::Group>();
297 
298   if (std::error_code EC = dumpCommonSection(Shdr, *S))
299     return EC;
300   // Get sh_info which is the signature.
301   const Elf_Sym *symbol = Obj.getSymbol(Shdr->sh_info);
302   const Elf_Shdr *symtab = Obj.getSection(Shdr->sh_link);
303   auto sectionContents = Obj.getSectionContents(Shdr);
304   if (std::error_code ec = sectionContents.getError())
305     return ec;
306   ErrorOr<StringRef> symbolName = Obj.getSymbolName(symtab, symbol);
307   if (std::error_code EC = symbolName.getError())
308     return EC;
309   S->Info = *symbolName;
310   const Elf_Word *groupMembers =
311       reinterpret_cast<const Elf_Word *>(sectionContents->data());
312   const long count = (Shdr->sh_size) / sizeof(Elf_Word);
313   ELFYAML::SectionOrType s;
314   for (int i = 0; i < count; i++) {
315     if (groupMembers[i] == llvm::ELF::GRP_COMDAT) {
316       s.sectionNameOrType = "GRP_COMDAT";
317     } else {
318       const Elf_Shdr *sHdr = Obj.getSection(groupMembers[i]);
319       ErrorOr<StringRef> sectionName = Obj.getSectionName(sHdr);
320       if (std::error_code ec = sectionName.getError())
321         return ec;
322       s.sectionNameOrType = *sectionName;
323     }
324     S->Members.push_back(s);
325   }
326   return S.release();
327 }
328 
329 template <class ELFT>
330 ErrorOr<ELFYAML::MipsABIFlags *>
331 ELFDumper<ELFT>::dumpMipsABIFlags(const Elf_Shdr *Shdr) {
332   assert(Shdr->sh_type == ELF::SHT_MIPS_ABIFLAGS &&
333          "Section type is not SHT_MIPS_ABIFLAGS");
334   auto S = make_unique<ELFYAML::MipsABIFlags>();
335   if (std::error_code EC = dumpCommonSection(Shdr, *S))
336     return EC;
337 
338   ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
339   if (std::error_code EC = ContentOrErr.getError())
340     return EC;
341 
342   auto *Flags = reinterpret_cast<const object::Elf_Mips_ABIFlags<ELFT> *>(
343       ContentOrErr.get().data());
344   S->Version = Flags->version;
345   S->ISALevel = Flags->isa_level;
346   S->ISARevision = Flags->isa_rev;
347   S->GPRSize = Flags->gpr_size;
348   S->CPR1Size = Flags->cpr1_size;
349   S->CPR2Size = Flags->cpr2_size;
350   S->FpABI = Flags->fp_abi;
351   S->ISAExtension = Flags->isa_ext;
352   S->ASEs = Flags->ases;
353   S->Flags1 = Flags->flags1;
354   S->Flags2 = Flags->flags2;
355   return S.release();
356 }
357 
358 template <class ELFT>
359 static std::error_code elf2yaml(raw_ostream &Out,
360                                 const object::ELFFile<ELFT> &Obj) {
361   ELFDumper<ELFT> Dumper(Obj);
362   ErrorOr<ELFYAML::Object *> YAMLOrErr = Dumper.dump();
363   if (std::error_code EC = YAMLOrErr.getError())
364     return EC;
365 
366   std::unique_ptr<ELFYAML::Object> YAML(YAMLOrErr.get());
367   yaml::Output Yout(Out);
368   Yout << *YAML;
369 
370   return std::error_code();
371 }
372 
373 std::error_code elf2yaml(raw_ostream &Out, const object::ObjectFile &Obj) {
374   if (const auto *ELFObj = dyn_cast<object::ELF32LEObjectFile>(&Obj))
375     return elf2yaml(Out, *ELFObj->getELFFile());
376 
377   if (const auto *ELFObj = dyn_cast<object::ELF32BEObjectFile>(&Obj))
378     return elf2yaml(Out, *ELFObj->getELFFile());
379 
380   if (const auto *ELFObj = dyn_cast<object::ELF64LEObjectFile>(&Obj))
381     return elf2yaml(Out, *ELFObj->getELFFile());
382 
383   if (const auto *ELFObj = dyn_cast<object::ELF64BEObjectFile>(&Obj))
384     return elf2yaml(Out, *ELFObj->getELFFile());
385 
386   return obj2yaml_error::unsupported_obj_file_format;
387 }
388