1 //===-- Support/ELF.h - ELF constants and data structures -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header contains common, non-processor-specific data structures and
11 // constants for the ELF file format.
13 // The details of the ELF32 bits in this file are largely based on
14 // the Tool Interface Standard (TIS) Executable and Linking Format
15 // (ELF) Specification Version 1.2, May 1995. The ELF64 stuff is not
16 // standardized, as far as I can tell. It was largely based on information
17 // I found in OpenBSD header files.
19 //===----------------------------------------------------------------------===//
21 #include "Support/DataTypes.h"
29 typedef uint32_t Elf32_Addr; // Program address
30 typedef uint16_t Elf32_Half;
31 typedef uint32_t Elf32_Off; // File offset
32 typedef int32_t Elf32_Sword;
33 typedef uint32_t Elf32_Word;
35 typedef uint64_t Elf64_Addr;
36 typedef uint64_t Elf64_Off;
37 typedef int32_t Elf64_Shalf;
38 typedef int32_t Elf64_Sword;
39 typedef uint32_t Elf64_Word;
40 typedef int64_t Elf64_Sxword;
41 typedef uint64_t Elf64_Xword;
42 typedef uint32_t Elf64_Half;
43 typedef uint16_t Elf64_Quarter;
45 // Object file magic string.
46 static const char ElfMagic[] = { 0x7f, 'E', 'L', 'F', '\0' };
49 unsigned char e_ident[16]; // ELF Identification bytes
50 Elf32_Half e_type; // Type of file (see ET_* below)
51 Elf32_Half e_machine; // Required architecture for this file (see EM_*)
52 Elf32_Word e_version; // Must be equal to 1
53 Elf32_Addr e_entry; // Address to jump to in order to start program
54 Elf32_Off e_phoff; // Program header table's file offset, in bytes
55 Elf32_Off e_shoff; // Section header table's file offset, in bytes
56 Elf32_Word e_flags; // Processor-specific flags
57 Elf32_Half e_ehsize; // Size of ELF header, in bytes
58 Elf32_Half e_phentsize; // Size of an entry in the program header table
59 Elf32_Half e_phnum; // Number of entries in the program header table
60 Elf32_Half e_shentsize; // Size of an entry in the section header table
61 Elf32_Half e_shnum; // Number of entries in the section header table
62 Elf32_Half e_shstrndx; // Sect hdr table index of sect name string table
63 bool checkMagic () const {
64 return (memcmp (e_ident, ElfMagic, strlen (ElfMagic))) == 0;
66 unsigned char getFileClass () const { return e_ident[4]; }
67 unsigned char getDataEncoding () { return e_ident[5]; }
70 // 64-bit ELF header. Fields are the same as for ELF32, but with different
73 unsigned char e_ident[16];
75 Elf64_Quarter e_machine;
81 Elf64_Quarter e_ehsize;
82 Elf64_Quarter e_phentsize;
83 Elf64_Quarter e_phnum;
84 Elf64_Quarter e_shentsize;
85 Elf64_Quarter e_shnum;
86 Elf64_Quarter e_shstrndx;
91 ET_NONE = 0, // No file type
92 ET_REL = 1, // Relocatable file
93 ET_EXEC = 2, // Executable file
94 ET_DYN = 3, // Shared object file
95 ET_CORE = 4, // Core file
96 ET_LOPROC = 0xff00, // Beginning of processor-specific codes
97 ET_HIPROC = 0xffff // Processor-specific
100 // Machine architectures
102 EM_NONE = 0, // No machine
103 EM_M32 = 1, // AT&T WE 32100
104 EM_SPARC = 2, // SPARC
105 EM_386 = 3, // Intel 386
106 EM_68K = 4, // Motorola 68000
107 EM_88K = 5, // Motorola 88000
108 EM_486 = 6, // Intel 486 (deprecated)
109 EM_860 = 7, // Intel 80860
110 EM_MIPS = 8, // MIPS R3000
111 EM_PPC = 20, // PowerPC
113 EM_ALPHA = 41, // DEC Alpha
114 EM_SPARCV9 = 43 // SPARC V9
117 // Object file classes.
119 ELFCLASS32 = 1, // 32-bit object file
120 ELFCLASS64 = 2 // 64-bit object file
123 // Object file byte orderings.
125 ELFDATA2LSB = 1, // Little-endian object file
126 ELFDATA2MSB = 2 // Big-endian object file
131 Elf32_Word sh_name; // Section name (index into string table)
132 Elf32_Word sh_type; // Section type (SHT_*)
133 Elf32_Word sh_flags; // Section flags (SHF_*)
134 Elf32_Addr sh_addr; // Address where section is to be loaded
135 Elf32_Off sh_offset; // File offset of section data, in bytes
136 Elf32_Word sh_size; // Size of section, in bytes
137 Elf32_Word sh_link; // Section type-specific header table index link
138 Elf32_Word sh_info; // Section type-specific extra information
139 Elf32_Word sh_addralign; // Section address alignment
140 Elf32_Word sh_entsize; // Size of records contained within the section
143 // Section header for ELF64 - same fields as ELF32, different types.
147 Elf64_Xword sh_flags;
153 Elf64_Xword sh_addralign;
154 Elf64_Xword sh_entsize;
157 // Special section indices.
159 SHN_UNDEF = 0, // Undefined, missing, irrelevant, or meaningless
160 SHN_LORESERVE = 0xff00, // Lowest reserved index
161 SHN_LOPROC = 0xff00, // Lowest processor-specific index
162 SHN_HIPROC = 0xff1f, // Highest processor-specific index
163 SHN_ABS = 0xfff1, // Symbol has absolute value; does not need relocation
164 SHN_COMMON = 0xfff2, // FORTRAN COMMON or C external global variables
165 SHN_HIRESERVE = 0xffff // Highest reserved index
170 SHT_NULL = 0, // No associated section (inactive entry).
171 SHT_PROGBITS = 1, // Program-defined contents.
172 SHT_SYMTAB = 2, // Symbol table.
173 SHT_STRTAB = 3, // String table.
174 SHT_RELA = 4, // Relocation entries; explicit addends.
175 SHT_HASH = 5, // Symbol hash table.
176 SHT_DYNAMIC = 6, // Information for dynamic linking.
177 SHT_NOTE = 7, // Information about the file.
178 SHT_NOBITS = 8, // Data occupies no space in the file.
179 SHT_REL = 9, // Relocation entries; no explicit addends.
180 SHT_SHLIB = 10, // Reserved.
181 SHT_DYNSYM = 11, // Symbol table.
182 SHT_LOPROC = 0x70000000, // Lowest processor architecture-specific type.
183 SHT_HIPROC = 0x7fffffff, // Highest processor architecture-specific type.
184 SHT_LOUSER = 0x80000000, // Lowest type reserved for applications.
185 SHT_HIUSER = 0xffffffff // Highest type reserved for applications.
190 SHF_WRITE = 0x1, // Section data should be writable during execution.
191 SHF_ALLOC = 0x2, // Section occupies memory during program execution.
192 SHF_EXECINSTR = 0x4, // Section contains executable machine instructions.
193 SHF_MASKPROC = 0xf0000000 // Bits indicating processor-specific flags.
196 // Symbol table entries.
198 Elf32_Word st_name; // Symbol name (index into string table)
199 Elf32_Addr st_value; // Value or address associated with the symbol
200 Elf32_Word st_size; // Size of the symbol
201 unsigned char st_info; // Symbol's type and binding attributes
202 unsigned char st_other; // Must be zero; reserved
203 Elf32_Half st_shndx; // Which section (header table index) it's defined in
205 // These accessors and mutators correspond to the ELF32_ST_BIND,
206 // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
207 unsigned char getBinding () const { return st_info >> 4; }
208 unsigned char getType () const { return st_info & 0x0f; }
209 void setBinding (unsigned char b) { setBindingAndType (b, getType ()); }
210 void setType (unsigned char t) { setBindingAndType (getBinding (), t); }
211 void setBindingAndType (unsigned char b, unsigned char t) {
212 st_info = (b << 4) + (t & 0x0f);
218 STB_LOCAL = 0, // Local symbol, not visible outside obj file containing def
219 STB_GLOBAL = 1, // Global symbol, visible to all object files being combined
220 STB_WEAK = 2, // Weak symbol, like global but lower-precedence
221 STB_LOPROC = 13, // Lowest processor-specific binding type
222 STB_HIPROC = 15 // Highest processor-specific binding type
227 STT_NOTYPE = 0, // Symbol's type is not specified
228 STT_OBJECT = 1, // Symbol is a data object (variable, array, etc.)
229 STT_FUNC = 2, // Symbol is executable code (function, etc.)
230 STT_SECTION = 3, // Symbol refers to a section
231 STT_FILE = 4, // Local, absolute symbol that refers to a file
232 STT_LOPROC = 13, // Lowest processor-specific symbol type
233 STT_HIPROC = 15 // Highest processor-specific symbol type
236 // Relocation entry, without explicit addend.
238 Elf32_Addr r_offset; // Location (file byte offset, or program virtual addr)
239 Elf32_Word r_info; // Symbol table index and type of relocation to apply
241 // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
242 // and ELF32_R_INFO macros defined in the ELF specification:
243 Elf32_Word getSymbol () const { return (r_info >> 8); }
244 unsigned char getType () const { return (unsigned char) (r_info & 0x0ff); }
245 void setSymbol (Elf32_Word s) { setSymbolAndType (s, getType ()); }
246 void setType (unsigned char t) { setSymbolAndType (getSymbol(), t); }
247 void setSymbolAndType (Elf32_Word s, unsigned char t) {
248 r_info = (s << 8) + t;
252 // Relocation entry with explicit addend.
254 Elf32_Addr r_offset; // Location (file byte offset, or program virtual addr)
255 Elf32_Word r_info; // Symbol table index and type of relocation to apply
256 Elf32_Sword r_addend; // Compute value for relocatable field by adding this
258 // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
259 // and ELF32_R_INFO macros defined in the ELF specification:
260 Elf32_Word getSymbol () const { return (r_info >> 8); }
261 unsigned char getType () const { return (unsigned char) (r_info & 0x0ff); }
262 void setSymbol (Elf32_Word s) { setSymbolAndType (s, getType ()); }
263 void setType (unsigned char t) { setSymbolAndType (getSymbol(), t); }
264 void setSymbolAndType (Elf32_Word s, unsigned char t) {
265 r_info = (s << 8) + t;
271 Elf32_Word p_type; // Type of segment
272 Elf32_Off p_offset; // File offset where segment is located, in bytes
273 Elf32_Addr p_vaddr; // Virtual address of beginning of segment
274 Elf32_Addr p_paddr; // Physical address of beginning of segment (OS-specific)
275 Elf32_Word p_filesz; // Num. of bytes in file image of segment (may be zero)
276 Elf32_Word p_memsz; // Num. of bytes in mem image of segment (may be zero)
277 Elf32_Word p_flags; // Segment flags
278 Elf32_Word p_align; // Segment alignment constraint
282 PT_NULL = 0, // Unused segment.
283 PT_LOAD = 1, // Loadable segment.
284 PT_DYNAMIC = 2, // Dynamic linking information.
285 PT_INTERP = 3, // Interpreter pathname.
286 PT_NOTE = 4, // Auxiliary information.
287 PT_SHLIB = 5, // Reserved.
288 PT_PHDR = 6, // The program header table itself.
289 PT_LOPROC = 0x70000000, // Lowest processor-specific program hdr entry type.
290 PT_HIPROC = 0x7fffffff // Highest processor-specific program hdr entry type.
293 } // end namespace ELF
295 } // end namespace llvm