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_Word Elf_Word;
27 
28   const object::ELFFile<ELFT> &Obj;
29 
30   std::error_code dumpSymbol(const Elf_Sym *Sym, bool IsDynamic,
31                              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::NoBitsSection *> dumpNoBitsSection(const Elf_Shdr *Shdr);
44   ErrorOr<ELFYAML::Group *> dumpGroup(const Elf_Shdr *Shdr);
45   ErrorOr<ELFYAML::MipsABIFlags *> dumpMipsABIFlags(const Elf_Shdr *Shdr);
46 
47 public:
48   ELFDumper(const object::ELFFile<ELFT> &O);
49   ErrorOr<ELFYAML::Object *> dump();
50 };
51 
52 }
53 
54 template <class ELFT>
55 ELFDumper<ELFT>::ELFDumper(const object::ELFFile<ELFT> &O)
56     : Obj(O) {}
57 
58 template <class ELFT>
59 ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
60   auto Y = make_unique<ELFYAML::Object>();
61 
62   // Dump header
63   Y->Header.Class = ELFYAML::ELF_ELFCLASS(Obj.getHeader()->getFileClass());
64   Y->Header.Data = ELFYAML::ELF_ELFDATA(Obj.getHeader()->getDataEncoding());
65   Y->Header.OSABI = Obj.getHeader()->e_ident[ELF::EI_OSABI];
66   Y->Header.Type = Obj.getHeader()->e_type;
67   Y->Header.Machine = Obj.getHeader()->e_machine;
68   Y->Header.Flags = Obj.getHeader()->e_flags;
69   Y->Header.Entry = Obj.getHeader()->e_entry;
70 
71   // Dump sections
72   for (const Elf_Shdr &Sec : Obj.sections()) {
73     switch (Sec.sh_type) {
74     case ELF::SHT_NULL:
75     case ELF::SHT_SYMTAB:
76     case ELF::SHT_DYNSYM:
77     case ELF::SHT_STRTAB:
78       // Do not dump these sections.
79       break;
80     case ELF::SHT_RELA: {
81       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelaSection(&Sec);
82       if (std::error_code EC = S.getError())
83         return EC;
84       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
85       break;
86     }
87     case ELF::SHT_REL: {
88       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelSection(&Sec);
89       if (std::error_code EC = S.getError())
90         return EC;
91       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
92       break;
93     }
94     case ELF::SHT_GROUP: {
95       ErrorOr<ELFYAML::Group *> G = dumpGroup(&Sec);
96       if (std::error_code EC = G.getError())
97         return EC;
98       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(G.get()));
99       break;
100     }
101     case ELF::SHT_MIPS_ABIFLAGS: {
102       ErrorOr<ELFYAML::MipsABIFlags *> G = dumpMipsABIFlags(&Sec);
103       if (std::error_code EC = G.getError())
104         return EC;
105       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(G.get()));
106       break;
107     }
108     case ELF::SHT_NOBITS: {
109       ErrorOr<ELFYAML::NoBitsSection *> S = dumpNoBitsSection(&Sec);
110       if (std::error_code EC = S.getError())
111         return EC;
112       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
113       break;
114     }
115     default: {
116       ErrorOr<ELFYAML::RawContentSection *> S = dumpContentSection(&Sec);
117       if (std::error_code EC = S.getError())
118         return EC;
119       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
120     }
121     }
122   }
123 
124   // Dump symbols
125   bool IsFirstSym = true;
126   for (auto SI = Obj.symbol_begin(), SE = Obj.symbol_end(); SI != SE; ++SI) {
127     if (IsFirstSym) {
128       IsFirstSym = false;
129       continue;
130     }
131 
132     ELFYAML::Symbol S;
133     if (std::error_code EC = ELFDumper<ELFT>::dumpSymbol(SI, false, S))
134       return EC;
135 
136     switch (SI->getBinding())
137     {
138     case ELF::STB_LOCAL:
139       Y->Symbols.Local.push_back(S);
140       break;
141     case ELF::STB_GLOBAL:
142       Y->Symbols.Global.push_back(S);
143       break;
144     case ELF::STB_WEAK:
145       Y->Symbols.Weak.push_back(S);
146       break;
147     default:
148       llvm_unreachable("Unknown ELF symbol binding");
149     }
150   }
151 
152   return Y.release();
153 }
154 
155 template <class ELFT>
156 std::error_code ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym, bool IsDynamic,
157                                             ELFYAML::Symbol &S) {
158   S.Type = Sym->getType();
159   S.Value = Sym->st_value;
160   S.Size = Sym->st_size;
161   S.Other = Sym->st_other;
162 
163   ErrorOr<StringRef> NameOrErr = Obj.getSymbolName(Sym, IsDynamic);
164   if (std::error_code EC = NameOrErr.getError())
165     return EC;
166   S.Name = NameOrErr.get();
167 
168   ErrorOr<const Elf_Shdr *> ShdrOrErr = Obj.getSection(&*Sym);
169   if (std::error_code EC = ShdrOrErr.getError())
170     return EC;
171   const Elf_Shdr *Shdr = *ShdrOrErr;
172   if (!Shdr)
173     return obj2yaml_error::success;
174 
175   NameOrErr = Obj.getSectionName(Shdr);
176   if (std::error_code EC = NameOrErr.getError())
177     return EC;
178   S.Section = NameOrErr.get();
179 
180   return obj2yaml_error::success;
181 }
182 
183 template <class ELFT>
184 template <class RelT>
185 std::error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
186                                                 const RelT *Rel,
187                                                 ELFYAML::Relocation &R) {
188   R.Type = Rel->getType(Obj.isMips64EL());
189   R.Offset = Rel->r_offset;
190   R.Addend = 0;
191 
192   auto NamePair = Obj.getRelocationSymbol(Shdr, Rel);
193   if (!NamePair.first)
194     return obj2yaml_error::success;
195 
196   const Elf_Shdr *SymTab = NamePair.first;
197   ErrorOr<const Elf_Shdr *> StrTabSec = Obj.getSection(SymTab->sh_link);
198   if (std::error_code EC = StrTabSec.getError())
199     return EC;
200   ErrorOr<StringRef> StrTabOrErr = Obj.getStringTable(*StrTabSec);
201   if (std::error_code EC = StrTabOrErr.getError())
202     return EC;
203   StringRef StrTab = *StrTabOrErr;
204 
205   ErrorOr<StringRef> NameOrErr = NamePair.second->getName(StrTab);
206   if (std::error_code EC = NameOrErr.getError())
207     return EC;
208   R.Symbol = NameOrErr.get();
209 
210   return obj2yaml_error::success;
211 }
212 
213 template <class ELFT>
214 std::error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
215                                                    ELFYAML::Section &S) {
216   S.Type = Shdr->sh_type;
217   S.Flags = Shdr->sh_flags;
218   S.Address = Shdr->sh_addr;
219   S.AddressAlign = Shdr->sh_addralign;
220 
221   ErrorOr<StringRef> NameOrErr = Obj.getSectionName(Shdr);
222   if (std::error_code EC = NameOrErr.getError())
223     return EC;
224   S.Name = NameOrErr.get();
225 
226   if (Shdr->sh_link != ELF::SHN_UNDEF) {
227     ErrorOr<const Elf_Shdr *> LinkSection = Obj.getSection(Shdr->sh_link);
228     if (std::error_code EC = LinkSection.getError())
229       return EC;
230     NameOrErr = Obj.getSectionName(*LinkSection);
231     if (std::error_code EC = NameOrErr.getError())
232       return EC;
233     S.Link = NameOrErr.get();
234   }
235 
236   return obj2yaml_error::success;
237 }
238 
239 template <class ELFT>
240 std::error_code
241 ELFDumper<ELFT>::dumpCommonRelocationSection(const Elf_Shdr *Shdr,
242                                              ELFYAML::RelocationSection &S) {
243   if (std::error_code EC = dumpCommonSection(Shdr, S))
244     return EC;
245 
246   ErrorOr<const Elf_Shdr *> InfoSection = Obj.getSection(Shdr->sh_info);
247   if (std::error_code EC = InfoSection.getError())
248     return EC;
249 
250   ErrorOr<StringRef> NameOrErr = Obj.getSectionName(*InfoSection);
251   if (std::error_code EC = NameOrErr.getError())
252     return EC;
253   S.Info = NameOrErr.get();
254 
255   return obj2yaml_error::success;
256 }
257 
258 template <class ELFT>
259 ErrorOr<ELFYAML::RelocationSection *>
260 ELFDumper<ELFT>::dumpRelSection(const Elf_Shdr *Shdr) {
261   assert(Shdr->sh_type == ELF::SHT_REL && "Section type is not SHT_REL");
262   auto S = make_unique<ELFYAML::RelocationSection>();
263 
264   if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
265     return EC;
266 
267   for (auto RI = Obj.rel_begin(Shdr), RE = Obj.rel_end(Shdr); RI != RE; ++RI) {
268     ELFYAML::Relocation R;
269     if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
270       return EC;
271     S->Relocations.push_back(R);
272   }
273 
274   return S.release();
275 }
276 
277 template <class ELFT>
278 ErrorOr<ELFYAML::RelocationSection *>
279 ELFDumper<ELFT>::dumpRelaSection(const Elf_Shdr *Shdr) {
280   assert(Shdr->sh_type == ELF::SHT_RELA && "Section type is not SHT_RELA");
281   auto S = make_unique<ELFYAML::RelocationSection>();
282 
283   if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
284     return EC;
285 
286   for (auto RI = Obj.rela_begin(Shdr), RE = Obj.rela_end(Shdr); RI != RE;
287        ++RI) {
288     ELFYAML::Relocation R;
289     if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
290       return EC;
291     R.Addend = RI->r_addend;
292     S->Relocations.push_back(R);
293   }
294 
295   return S.release();
296 }
297 
298 template <class ELFT>
299 ErrorOr<ELFYAML::RawContentSection *>
300 ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
301   auto S = make_unique<ELFYAML::RawContentSection>();
302 
303   if (std::error_code EC = dumpCommonSection(Shdr, *S))
304     return EC;
305 
306   ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
307   if (std::error_code EC = ContentOrErr.getError())
308     return EC;
309   S->Content = yaml::BinaryRef(ContentOrErr.get());
310   S->Size = S->Content.binary_size();
311 
312   return S.release();
313 }
314 
315 template <class ELFT>
316 ErrorOr<ELFYAML::NoBitsSection *>
317 ELFDumper<ELFT>::dumpNoBitsSection(const Elf_Shdr *Shdr) {
318   auto S = make_unique<ELFYAML::NoBitsSection>();
319 
320   if (std::error_code EC = dumpCommonSection(Shdr, *S))
321     return EC;
322   S->Size = Shdr->sh_size;
323 
324   return S.release();
325 }
326 
327 template <class ELFT>
328 ErrorOr<ELFYAML::Group *> ELFDumper<ELFT>::dumpGroup(const Elf_Shdr *Shdr) {
329   auto S = make_unique<ELFYAML::Group>();
330 
331   if (std::error_code EC = dumpCommonSection(Shdr, *S))
332     return EC;
333   // Get sh_info which is the signature.
334   const Elf_Sym *symbol = Obj.getSymbol(Shdr->sh_info);
335   ErrorOr<const Elf_Shdr *> Symtab = Obj.getSection(Shdr->sh_link);
336   if (std::error_code EC = Symtab.getError())
337     return EC;
338   ErrorOr<const Elf_Shdr *> StrTabSec = Obj.getSection((*Symtab)->sh_link);
339   if (std::error_code EC = StrTabSec.getError())
340     return EC;
341   ErrorOr<StringRef> StrTabOrErr = Obj.getStringTable(*StrTabSec);
342   if (std::error_code EC = StrTabOrErr.getError())
343     return EC;
344   StringRef StrTab = *StrTabOrErr;
345   auto sectionContents = Obj.getSectionContents(Shdr);
346   if (std::error_code ec = sectionContents.getError())
347     return ec;
348   ErrorOr<StringRef> symbolName = symbol->getName(StrTab);
349   if (std::error_code EC = symbolName.getError())
350     return EC;
351   S->Info = *symbolName;
352   const Elf_Word *groupMembers =
353       reinterpret_cast<const Elf_Word *>(sectionContents->data());
354   const long count = (Shdr->sh_size) / sizeof(Elf_Word);
355   ELFYAML::SectionOrType s;
356   for (int i = 0; i < count; i++) {
357     if (groupMembers[i] == llvm::ELF::GRP_COMDAT) {
358       s.sectionNameOrType = "GRP_COMDAT";
359     } else {
360       ErrorOr<const Elf_Shdr *> sHdr = Obj.getSection(groupMembers[i]);
361       if (std::error_code EC = sHdr.getError())
362         return EC;
363       ErrorOr<StringRef> sectionName = Obj.getSectionName(*sHdr);
364       if (std::error_code ec = sectionName.getError())
365         return ec;
366       s.sectionNameOrType = *sectionName;
367     }
368     S->Members.push_back(s);
369   }
370   return S.release();
371 }
372 
373 template <class ELFT>
374 ErrorOr<ELFYAML::MipsABIFlags *>
375 ELFDumper<ELFT>::dumpMipsABIFlags(const Elf_Shdr *Shdr) {
376   assert(Shdr->sh_type == ELF::SHT_MIPS_ABIFLAGS &&
377          "Section type is not SHT_MIPS_ABIFLAGS");
378   auto S = make_unique<ELFYAML::MipsABIFlags>();
379   if (std::error_code EC = dumpCommonSection(Shdr, *S))
380     return EC;
381 
382   ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
383   if (std::error_code EC = ContentOrErr.getError())
384     return EC;
385 
386   auto *Flags = reinterpret_cast<const object::Elf_Mips_ABIFlags<ELFT> *>(
387       ContentOrErr.get().data());
388   S->Version = Flags->version;
389   S->ISALevel = Flags->isa_level;
390   S->ISARevision = Flags->isa_rev;
391   S->GPRSize = Flags->gpr_size;
392   S->CPR1Size = Flags->cpr1_size;
393   S->CPR2Size = Flags->cpr2_size;
394   S->FpABI = Flags->fp_abi;
395   S->ISAExtension = Flags->isa_ext;
396   S->ASEs = Flags->ases;
397   S->Flags1 = Flags->flags1;
398   S->Flags2 = Flags->flags2;
399   return S.release();
400 }
401 
402 template <class ELFT>
403 static std::error_code elf2yaml(raw_ostream &Out,
404                                 const object::ELFFile<ELFT> &Obj) {
405   ELFDumper<ELFT> Dumper(Obj);
406   ErrorOr<ELFYAML::Object *> YAMLOrErr = Dumper.dump();
407   if (std::error_code EC = YAMLOrErr.getError())
408     return EC;
409 
410   std::unique_ptr<ELFYAML::Object> YAML(YAMLOrErr.get());
411   yaml::Output Yout(Out);
412   Yout << *YAML;
413 
414   return std::error_code();
415 }
416 
417 std::error_code elf2yaml(raw_ostream &Out, const object::ObjectFile &Obj) {
418   if (const auto *ELFObj = dyn_cast<object::ELF32LEObjectFile>(&Obj))
419     return elf2yaml(Out, *ELFObj->getELFFile());
420 
421   if (const auto *ELFObj = dyn_cast<object::ELF32BEObjectFile>(&Obj))
422     return elf2yaml(Out, *ELFObj->getELFFile());
423 
424   if (const auto *ELFObj = dyn_cast<object::ELF64LEObjectFile>(&Obj))
425     return elf2yaml(Out, *ELFObj->getELFFile());
426 
427   if (const auto *ELFObj = dyn_cast<object::ELF64BEObjectFile>(&Obj))
428     return elf2yaml(Out, *ELFObj->getELFFile());
429 
430   return obj2yaml_error::unsupported_obj_file_format;
431 }
432