1 //===- InputFiles.cpp -----------------------------------------------------===//
2 //
3 //                             The LLVM Linker
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 "InputFiles.h"
11 #include "Chunks.h"
12 #include "Symbols.h"
13 #include "Driver.h"
14 #include "llvm/ADT/STLExtras.h"
15 
16 using namespace llvm::ELF;
17 
18 using namespace lld;
19 using namespace lld::elf2;
20 
21 template <class ELFT> void elf2::ObjectFile<ELFT>::parse() {
22   // Parse a memory buffer as a ELF file.
23   std::error_code EC;
24   ELFObj = llvm::make_unique<ELFFile<ELFT>>(MB.getBuffer(), EC);
25   error(EC);
26 
27   // Read section and symbol tables.
28   initializeChunks();
29   initializeSymbols();
30 }
31 
32 template <class ELFT> void elf2::ObjectFile<ELFT>::initializeChunks() {
33   uint64_t Size = ELFObj->getNumSections();
34   Chunks.reserve(Size);
35   for (const Elf_Shdr &Sec : ELFObj->sections()) {
36     if (Sec.sh_flags & SHF_ALLOC) {
37       auto *C = new (Alloc) SectionChunk<ELFT>(this->getObj(), &Sec);
38       Chunks.push_back(C);
39     }
40   }
41 }
42 
43 template <class ELFT> void elf2::ObjectFile<ELFT>::initializeSymbols() {
44   const Elf_Shdr *Symtab = ELFObj->getDotSymtabSec();
45   ErrorOr<StringRef> StringTableOrErr =
46       ELFObj->getStringTableForSymtab(*Symtab);
47   error(StringTableOrErr.getError());
48   StringRef StringTable = *StringTableOrErr;
49 
50   Elf_Sym_Range Syms = ELFObj->symbols();
51   Syms = Elf_Sym_Range(Syms.begin() + 1, Syms.end());
52   auto NumSymbols = std::distance(Syms.begin(), Syms.end());
53   SymbolBodies.reserve(NumSymbols);
54   for (const Elf_Sym &Sym : Syms) {
55     if (SymbolBody *Body = createSymbolBody(StringTable, &Sym))
56       SymbolBodies.push_back(Body);
57   }
58 }
59 
60 template <class ELFT>
61 SymbolBody *elf2::ObjectFile<ELFT>::createSymbolBody(StringRef StringTable,
62                                                      const Elf_Sym *Sym) {
63   ErrorOr<StringRef> NameOrErr = Sym->getName(StringTable);
64   error(NameOrErr.getError());
65   StringRef Name = *NameOrErr;
66   if (Sym->isUndefined())
67     return new (Alloc) Undefined(Name);
68   return new (Alloc) DefinedRegular<ELFT>(this, Sym);
69 }
70 
71 namespace lld {
72 namespace elf2 {
73 template class elf2::ObjectFile<llvm::object::ELF32LE>;
74 template class elf2::ObjectFile<llvm::object::ELF32BE>;
75 template class elf2::ObjectFile<llvm::object::ELF64LE>;
76 template class elf2::ObjectFile<llvm::object::ELF64BE>;
77 }
78 }
79