1 //===-- ELFDump.cpp - ELF-specific dumper -----------------------*- 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 /// \file
11 /// This file implements the ELF-specific dumper for llvm-objdump.
12 ///
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm-objdump.h"
16 #include "llvm/Object/ELFObjectFile.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/MathExtras.h"
19 #include "llvm/Support/raw_ostream.h"
20
21 using namespace llvm;
22 using namespace llvm::object;
23
24 template <class ELFT>
getDynamicStrTab(const ELFFile<ELFT> * Elf)25 Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> *Elf) {
26 typedef ELFFile<ELFT> ELFO;
27
28 auto DynamicEntriesOrError = Elf->dynamicEntries();
29 if (!DynamicEntriesOrError)
30 return DynamicEntriesOrError.takeError();
31
32 for (const typename ELFO::Elf_Dyn &Dyn : *DynamicEntriesOrError) {
33 if (Dyn.d_tag == ELF::DT_STRTAB) {
34 auto MappedAddrOrError = Elf->toMappedAddr(Dyn.getPtr());
35 if (!MappedAddrOrError)
36 consumeError(MappedAddrOrError.takeError());
37 return StringRef(reinterpret_cast<const char *>(*MappedAddrOrError));
38 }
39 }
40
41 // If the dynamic segment is not present, we fall back on the sections.
42 auto SectionsOrError = Elf->sections();
43 if (!SectionsOrError)
44 return SectionsOrError.takeError();
45
46 for (const typename ELFO::Elf_Shdr &Sec : *SectionsOrError) {
47 if (Sec.sh_type == ELF::SHT_DYNSYM)
48 return Elf->getStringTableForSymtab(Sec);
49 }
50
51 return createError("dynamic string table not found");
52 }
53
54 template <class ELFT>
printDynamicSection(const ELFFile<ELFT> * Elf,StringRef Filename)55 void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
56 auto ProgramHeaderOrError = Elf->program_headers();
57 if (!ProgramHeaderOrError)
58 report_error(Filename, ProgramHeaderOrError.takeError());
59
60 auto DynamicEntriesOrError = Elf->dynamicEntries();
61 if (!DynamicEntriesOrError)
62 report_error(Filename, DynamicEntriesOrError.takeError());
63
64 outs() << "Dynamic Section:\n";
65 for (const auto &Dyn : *DynamicEntriesOrError) {
66 if (Dyn.d_tag == ELF::DT_NULL)
67 continue;
68
69 StringRef Str = StringRef(Elf->getDynamicTagAsString(Dyn.d_tag));
70
71 if (Str.empty()) {
72 std::string HexStr = utohexstr(static_cast<uint64_t>(Dyn.d_tag), true);
73 outs() << format(" 0x%-19s", HexStr.c_str());
74 } else {
75 // We use "-21" in order to match GNU objdump's output.
76 outs() << format(" %-21s", Str.data());
77 }
78
79 const char *Fmt =
80 ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
81 if (Dyn.d_tag == ELF::DT_NEEDED) {
82 Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
83 if (StrTabOrErr) {
84 const char *Data = StrTabOrErr.get().data();
85 outs() << (Data + Dyn.d_un.d_val) << "\n";
86 continue;
87 }
88 warn(errorToErrorCode(StrTabOrErr.takeError()).message());
89 consumeError(StrTabOrErr.takeError());
90 }
91 outs() << format(Fmt, (uint64_t)Dyn.d_un.d_val);
92 }
93 }
94
printProgramHeaders(const ELFFile<ELFT> * o)95 template <class ELFT> void printProgramHeaders(const ELFFile<ELFT> *o) {
96 typedef ELFFile<ELFT> ELFO;
97 outs() << "Program Header:\n";
98 auto ProgramHeaderOrError = o->program_headers();
99 if (!ProgramHeaderOrError)
100 report_fatal_error(
101 errorToErrorCode(ProgramHeaderOrError.takeError()).message());
102 for (const typename ELFO::Elf_Phdr &Phdr : *ProgramHeaderOrError) {
103 switch (Phdr.p_type) {
104 case ELF::PT_DYNAMIC:
105 outs() << " DYNAMIC ";
106 break;
107 case ELF::PT_GNU_EH_FRAME:
108 outs() << "EH_FRAME ";
109 break;
110 case ELF::PT_GNU_RELRO:
111 outs() << " RELRO ";
112 break;
113 case ELF::PT_GNU_STACK:
114 outs() << " STACK ";
115 break;
116 case ELF::PT_INTERP:
117 outs() << " INTERP ";
118 break;
119 case ELF::PT_LOAD:
120 outs() << " LOAD ";
121 break;
122 case ELF::PT_NOTE:
123 outs() << " NOTE ";
124 break;
125 case ELF::PT_OPENBSD_BOOTDATA:
126 outs() << " OPENBSD_BOOTDATA ";
127 break;
128 case ELF::PT_OPENBSD_RANDOMIZE:
129 outs() << " OPENBSD_RANDOMIZE ";
130 break;
131 case ELF::PT_OPENBSD_WXNEEDED:
132 outs() << " OPENBSD_WXNEEDED ";
133 break;
134 case ELF::PT_PHDR:
135 outs() << " PHDR ";
136 break;
137 case ELF::PT_TLS:
138 outs() << " TLS ";
139 break;
140 default:
141 outs() << " UNKNOWN ";
142 }
143
144 const char *Fmt = ELFT::Is64Bits ? "0x%016" PRIx64 " " : "0x%08" PRIx64 " ";
145
146 outs() << "off " << format(Fmt, (uint64_t)Phdr.p_offset) << "vaddr "
147 << format(Fmt, (uint64_t)Phdr.p_vaddr) << "paddr "
148 << format(Fmt, (uint64_t)Phdr.p_paddr)
149 << format("align 2**%u\n",
150 countTrailingZeros<uint64_t>(Phdr.p_align))
151 << " filesz " << format(Fmt, (uint64_t)Phdr.p_filesz)
152 << "memsz " << format(Fmt, (uint64_t)Phdr.p_memsz) << "flags "
153 << ((Phdr.p_flags & ELF::PF_R) ? "r" : "-")
154 << ((Phdr.p_flags & ELF::PF_W) ? "w" : "-")
155 << ((Phdr.p_flags & ELF::PF_X) ? "x" : "-") << "\n";
156 }
157 outs() << "\n";
158 }
159
printELFFileHeader(const object::ObjectFile * Obj)160 void llvm::printELFFileHeader(const object::ObjectFile *Obj) {
161 // Little-endian 32-bit
162 if (const ELF32LEObjectFile *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
163 printProgramHeaders(ELFObj->getELFFile());
164
165 // Big-endian 32-bit
166 if (const ELF32BEObjectFile *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
167 printProgramHeaders(ELFObj->getELFFile());
168
169 // Little-endian 64-bit
170 if (const ELF64LEObjectFile *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
171 printProgramHeaders(ELFObj->getELFFile());
172
173 // Big-endian 64-bit
174 if (const ELF64BEObjectFile *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
175 printProgramHeaders(ELFObj->getELFFile());
176 }
177
printELFDynamicSection(const object::ObjectFile * Obj)178 void llvm::printELFDynamicSection(const object::ObjectFile *Obj) {
179 // Little-endian 32-bit
180 if (const ELF32LEObjectFile *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
181 printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
182
183 // Big-endian 32-bit
184 if (const ELF32BEObjectFile *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
185 printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
186
187 // Little-endian 64-bit
188 if (const ELF64LEObjectFile *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
189 printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
190
191 // Big-endian 64-bit
192 if (const ELF64BEObjectFile *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
193 printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
194 }
195