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
18using namespace llvm;
19
20namespace {
21
22template <class ELFT>
23class ELFDumper {
24  typedef typename object::ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
25  typedef typename object::ELFFile<ELFT>::Elf_Sym_Iter Elf_Sym_Iter;
26
27  const object::ELFFile<ELFT> &Obj;
28
29  std::error_code dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S);
30  std::error_code dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
31  std::error_code dumpCommonRelocationSection(const Elf_Shdr *Shdr,
32                                              ELFYAML::RelocationSection &S);
33  template <class RelT>
34  std::error_code dumpRelocation(const Elf_Shdr *Shdr, const RelT *Rel,
35                                 ELFYAML::Relocation &R);
36
37  ErrorOr<ELFYAML::RelocationSection *> dumpRelSection(const Elf_Shdr *Shdr);
38  ErrorOr<ELFYAML::RelocationSection *> dumpRelaSection(const Elf_Shdr *Shdr);
39  ErrorOr<ELFYAML::RawContentSection *>
40  dumpContentSection(const Elf_Shdr *Shdr);
41
42public:
43  ELFDumper(const object::ELFFile<ELFT> &O);
44  ErrorOr<ELFYAML::Object *> dump();
45};
46
47}
48
49template <class ELFT>
50ELFDumper<ELFT>::ELFDumper(const object::ELFFile<ELFT> &O)
51    : Obj(O) {}
52
53template <class ELFT>
54ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
55  auto Y = make_unique<ELFYAML::Object>();
56
57  // Dump header
58  Y->Header.Class = ELFYAML::ELF_ELFCLASS(Obj.getHeader()->getFileClass());
59  Y->Header.Data = ELFYAML::ELF_ELFDATA(Obj.getHeader()->getDataEncoding());
60  Y->Header.OSABI = Obj.getHeader()->e_ident[ELF::EI_OSABI];
61  Y->Header.Type = Obj.getHeader()->e_type;
62  Y->Header.Machine = Obj.getHeader()->e_machine;
63  Y->Header.Flags = Obj.getHeader()->e_flags;
64  Y->Header.Entry = Obj.getHeader()->e_entry;
65
66  // Dump sections
67  for (const Elf_Shdr &Sec : Obj.sections()) {
68    switch (Sec.sh_type) {
69    case ELF::SHT_NULL:
70    case ELF::SHT_SYMTAB:
71    case ELF::SHT_DYNSYM:
72    case ELF::SHT_STRTAB:
73      // Do not dump these sections.
74      break;
75    case ELF::SHT_RELA: {
76      ErrorOr<ELFYAML::RelocationSection *> S = dumpRelaSection(&Sec);
77      if (std::error_code EC = S.getError())
78        return EC;
79      Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
80      break;
81    }
82    case ELF::SHT_REL: {
83      ErrorOr<ELFYAML::RelocationSection *> S = dumpRelSection(&Sec);
84      if (std::error_code EC = S.getError())
85        return EC;
86      Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
87      break;
88    }
89    // FIXME: Support SHT_GROUP section format.
90    default: {
91      ErrorOr<ELFYAML::RawContentSection *> S = dumpContentSection(&Sec);
92      if (std::error_code EC = S.getError())
93        return EC;
94      Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
95    }
96    }
97  }
98
99  // Dump symbols
100  bool IsFirstSym = true;
101  for (auto SI = Obj.begin_symbols(), SE = Obj.end_symbols(); SI != SE; ++SI) {
102    if (IsFirstSym) {
103      IsFirstSym = false;
104      continue;
105    }
106
107    ELFYAML::Symbol S;
108    if (std::error_code EC = ELFDumper<ELFT>::dumpSymbol(SI, S))
109      return EC;
110
111    switch (SI->getBinding())
112    {
113    case ELF::STB_LOCAL:
114      Y->Symbols.Local.push_back(S);
115      break;
116    case ELF::STB_GLOBAL:
117      Y->Symbols.Global.push_back(S);
118      break;
119    case ELF::STB_WEAK:
120      Y->Symbols.Weak.push_back(S);
121      break;
122    default:
123      llvm_unreachable("Unknown ELF symbol binding");
124    }
125  }
126
127  return Y.release();
128}
129
130template <class ELFT>
131std::error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym,
132                                            ELFYAML::Symbol &S) {
133  S.Type = Sym->getType();
134  S.Value = Sym->st_value;
135  S.Size = Sym->st_size;
136  S.Visibility = Sym->st_other & 0x3;
137
138  ErrorOr<StringRef> NameOrErr = Obj.getSymbolName(Sym);
139  if (std::error_code EC = NameOrErr.getError())
140    return EC;
141  S.Name = NameOrErr.get();
142
143  const Elf_Shdr *Shdr = Obj.getSection(&*Sym);
144  if (!Shdr)
145    return obj2yaml_error::success;
146
147  NameOrErr = Obj.getSectionName(Shdr);
148  if (std::error_code EC = NameOrErr.getError())
149    return EC;
150  S.Section = NameOrErr.get();
151
152  return obj2yaml_error::success;
153}
154
155template <class ELFT>
156template <class RelT>
157std::error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
158                                                const RelT *Rel,
159                                                ELFYAML::Relocation &R) {
160  R.Type = Rel->getType(Obj.isMips64EL());
161  R.Offset = Rel->r_offset;
162  R.Addend = 0;
163
164  auto NamePair = Obj.getRelocationSymbol(Shdr, Rel);
165  if (!NamePair.first)
166    return obj2yaml_error::success;
167
168  ErrorOr<StringRef> NameOrErr =
169      Obj.getSymbolName(NamePair.first, NamePair.second);
170  if (std::error_code EC = NameOrErr.getError())
171    return EC;
172  R.Symbol = NameOrErr.get();
173
174  return obj2yaml_error::success;
175}
176
177template <class ELFT>
178std::error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
179                                                   ELFYAML::Section &S) {
180  S.Type = Shdr->sh_type;
181  S.Flags = Shdr->sh_flags;
182  S.Address = Shdr->sh_addr;
183  S.AddressAlign = Shdr->sh_addralign;
184
185  ErrorOr<StringRef> NameOrErr = Obj.getSectionName(Shdr);
186  if (std::error_code EC = NameOrErr.getError())
187    return EC;
188  S.Name = NameOrErr.get();
189
190  if (Shdr->sh_link != ELF::SHN_UNDEF) {
191    if (const Elf_Shdr *LinkSection = Obj.getSection(Shdr->sh_link)) {
192      NameOrErr = Obj.getSectionName(LinkSection);
193      if (std::error_code EC = NameOrErr.getError())
194        return EC;
195      S.Link = NameOrErr.get();
196    }
197  }
198
199  return obj2yaml_error::success;
200}
201
202template <class ELFT>
203std::error_code
204ELFDumper<ELFT>::dumpCommonRelocationSection(const Elf_Shdr *Shdr,
205                                             ELFYAML::RelocationSection &S) {
206  if (std::error_code EC = dumpCommonSection(Shdr, S))
207    return EC;
208
209  if (const Elf_Shdr *InfoSection = Obj.getSection(Shdr->sh_info)) {
210    ErrorOr<StringRef> NameOrErr = Obj.getSectionName(InfoSection);
211    if (std::error_code EC = NameOrErr.getError())
212      return EC;
213    S.Info = NameOrErr.get();
214  }
215
216  return obj2yaml_error::success;
217}
218
219template <class ELFT>
220ErrorOr<ELFYAML::RelocationSection *>
221ELFDumper<ELFT>::dumpRelSection(const Elf_Shdr *Shdr) {
222  assert(Shdr->sh_type == ELF::SHT_REL && "Section type is not SHT_REL");
223  auto S = make_unique<ELFYAML::RelocationSection>();
224
225  if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
226    return EC;
227
228  for (auto RI = Obj.begin_rel(Shdr), RE = Obj.end_rel(Shdr); RI != RE;
229       ++RI) {
230    ELFYAML::Relocation R;
231    if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
232      return EC;
233    S->Relocations.push_back(R);
234  }
235
236  return S.release();
237}
238
239template <class ELFT>
240ErrorOr<ELFYAML::RelocationSection *>
241ELFDumper<ELFT>::dumpRelaSection(const Elf_Shdr *Shdr) {
242  assert(Shdr->sh_type == ELF::SHT_RELA && "Section type is not SHT_RELA");
243  auto S = make_unique<ELFYAML::RelocationSection>();
244
245  if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
246    return EC;
247
248  for (auto RI = Obj.begin_rela(Shdr), RE = Obj.end_rela(Shdr); RI != RE;
249       ++RI) {
250    ELFYAML::Relocation R;
251    if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
252      return EC;
253    R.Addend = RI->r_addend;
254    S->Relocations.push_back(R);
255  }
256
257  return S.release();
258}
259
260template <class ELFT>
261ErrorOr<ELFYAML::RawContentSection *>
262ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
263  auto S = make_unique<ELFYAML::RawContentSection>();
264
265  if (std::error_code EC = dumpCommonSection(Shdr, *S))
266    return EC;
267
268  ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
269  if (std::error_code EC = ContentOrErr.getError())
270    return EC;
271  S->Content = yaml::BinaryRef(ContentOrErr.get());
272  S->Size = S->Content.binary_size();
273
274  return S.release();
275}
276
277template <class ELFT>
278static std::error_code elf2yaml(raw_ostream &Out,
279                                const object::ELFFile<ELFT> &Obj) {
280  ELFDumper<ELFT> Dumper(Obj);
281  ErrorOr<ELFYAML::Object *> YAMLOrErr = Dumper.dump();
282  if (std::error_code EC = YAMLOrErr.getError())
283    return EC;
284
285  std::unique_ptr<ELFYAML::Object> YAML(YAMLOrErr.get());
286  yaml::Output Yout(Out);
287  Yout << *YAML;
288
289  return object::object_error::success;
290}
291
292std::error_code elf2yaml(raw_ostream &Out, const object::ObjectFile &Obj) {
293  if (const auto *ELFObj = dyn_cast<object::ELF32LEObjectFile>(&Obj))
294    return elf2yaml(Out, *ELFObj->getELFFile());
295
296  if (const auto *ELFObj = dyn_cast<object::ELF32BEObjectFile>(&Obj))
297    return elf2yaml(Out, *ELFObj->getELFFile());
298
299  if (const auto *ELFObj = dyn_cast<object::ELF64LEObjectFile>(&Obj))
300    return elf2yaml(Out, *ELFObj->getELFFile());
301
302  if (const auto *ELFObj = dyn_cast<object::ELF64BEObjectFile>(&Obj))
303    return elf2yaml(Out, *ELFObj->getELFFile());
304
305  return obj2yaml_error::unsupported_obj_file_format;
306}
307