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 this file are largely based on the Tool Interface Standard
14 // (TIS) Executable and Linking Format (ELF) Specification Version 1.2,
17 //===----------------------------------------------------------------------===//
19 #include "Support/DataTypes.h"
27 typedef uint32_t Elf32_Addr; // Program address
28 typedef uint16_t Elf32_Half;
29 typedef uint32_t Elf32_Off; // File offset
30 typedef int32_t Elf32_Sword;
31 typedef uint32_t Elf32_Word;
33 // Object file magic string.
34 static const char *ElfMagic = "\x7fELF";
37 unsigned char e_ident[16]; // ELF Identification bytes
38 Elf32_Half e_type; // Type of file (see ET_* below)
39 Elf32_Half e_machine; // Required architecture for this file (see EM_*)
40 Elf32_Word e_version; // Must be equal to 1
41 Elf32_Addr e_entry; // Address to jump to in order to start program
42 Elf32_Off e_phoff; // Program header table's file offset, in bytes
43 Elf32_Off e_shoff; // Section header table's file offset, in bytes
44 Elf32_Word e_flags; // Processor-specific flags
45 Elf32_Half e_ehsize; // Size of ELF header, in bytes
46 Elf32_Half e_phentsize; // Size of an entry in the program header table
47 Elf32_Half e_phnum; // Number of entries in the program header table
48 Elf32_Half e_shentsize; // Size of an entry in the section header table
49 Elf32_Half e_shnum; // Number of entries in the section header table
50 Elf32_Half e_shstrndx; // Sect hdr table index of sect name string table
51 bool checkMagic () const {
52 return (memcmp (e_ident, ElfMagic, strlen (ElfMagic)) == 0;
54 unsigned char getFileClass () const { return e_ident[4]; }
55 unsigned char getDataEncoding () { return e_ident[5]; }
60 ET_NONE = 0, // No file type
61 ET_REL = 1, // Relocatable file
62 ET_EXEC = 2, // Executable file
63 ET_DYN = 3, // Shared object file
64 ET_CORE = 4, // Core file
65 ET_LOPROC = 0xff00, // Beginning of processor-specific codes
66 ET_HIPROC = 0xffff // Processor-specific
69 // Machine architectures
71 EM_NONE = 0, // No machine
72 EM_M32 = 1, // AT&T WE 32100
73 EM_SPARC = 2, // SPARC
74 EM_386 = 3, // Intel 386
75 EM_68K = 4, // Motorola 68000
76 EM_88K = 5, // Motorola 88000
77 EM_860 = 7, // Intel 80860
78 EM_MIPS = 8 // MIPS R3000
81 // Object file classes.
83 ELFCLASS32 = 1, // 32-bit object file
84 ELFCLASS64 = 2 // 64-bit object file
87 // Object file byte orderings.
89 ELFDATA2LSB = 1, // Little-endian object file
90 ELFDATA2MSB = 2 // Big-endian object file
95 Elf32_Word sh_name; // Section name (index into string table)
96 Elf32_Word sh_type; // Section type (SHT_*)
97 Elf32_Word sh_flags; // Section flags (SHF_*)
98 Elf32_Addr sh_addr; // Address where section is to be loaded
99 Elf32_Off sh_offset; // File offset of section data, in bytes
100 Elf32_Word sh_size; // Size of section, in bytes
101 Elf32_Word sh_link; // Section type-specific header table index link
102 Elf32_Word sh_info; // Section type-specific extra information
103 Elf32_Word sh_addralign; // Section address alignment
104 Elf32_Word sh_entsize; // Size of records contained within the section
107 // Special section indices.
109 SHN_UNDEF = 0, // Undefined, missing, irrelevant, or meaningless
110 SHN_LORESERVE = 0xff00, // Lowest reserved index
111 SHN_LOPROC = 0xff00, // Lowest processor-specific index
112 SHN_HIPROC = 0xff1f, // Highest processor-specific index
113 SHN_ABS = 0xfff1, // Symbol has absolute value; does not need relocation
114 SHN_COMMON = 0xfff2, // FORTRAN COMMON or C external global variables
115 SHN_HIRESERVE = 0xffff // Highest reserved index
120 SHT_NULL = 0, // No associated section (inactive entry).
121 SHT_PROGBITS = 1, // Program-defined contents.
122 SHT_SYMTAB = 2, // Symbol table.
123 SHT_STRTAB = 3, // String table.
124 SHT_RELA = 4, // Relocation entries; explicit addends.
125 SHT_HASH = 5, // Symbol hash table.
126 SHT_DYNAMIC = 6, // Information for dynamic linking.
127 SHT_NOTE = 7, // Information about the file.
128 SHT_NOBITS = 8, // Data occupies no space in the file.
129 SHT_REL = 9, // Relocation entries; no explicit addends.
130 SHT_SHLIB = 10, // Reserved.
131 SHT_DYNSYM = 11, // Symbol table.
132 SHT_LOPROC = 0x70000000, // Lowest processor architecture-specific type.
133 SHT_HIPROC = 0x7fffffff, // Highest processor architecture-specific type.
134 SHT_LOUSER = 0x80000000, // Lowest type reserved for applications.
135 SHT_HIUSER = 0xffffffff // Highest type reserved for applications.
140 SHF_WRITE = 0x1, // Section data should be writable during execution.
141 SHF_ALLOC = 0x2, // Section occupies memory during program execution.
142 SHF_EXECINSTR = 0x4, // Section contains executable machine instructions.
143 SHF_MASKPROC = 0xf0000000 // Bits indicating processor-specific flags.
146 // Symbol table entries.
148 Elf32_Word st_name; // Symbol name (index into string table)
149 Elf32_Addr st_value; // Value or address associated with the symbol
150 Elf32_Word st_size; // Size of the symbol
151 unsigned char st_info; // Symbol's type and binding attributes
152 unsigned char st_other; // Must be zero; reserved
153 Elf32_Half st_shndx; // Which section (header table index) it's defined in
155 // These accessors and mutators correspond to the ELF32_ST_BIND,
156 // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
157 unsigned char getBinding () const { return st_info >> 4; }
158 unsigned char getType () const { return st_info & 0x0f; }
159 void setBinding (unsigned char b) { setBindingAndType (b, getType ()); }
160 void setType (unsigned char t) { setBindingAndType (getBinding (), t); }
161 void setBindingAndType (unsigned char b, unsigned char t) {
162 st_info = (b << 4) + (t & 0x0f);
168 STB_LOCAL = 0, // Local symbol, not visible outside obj file containing def
169 STB_GLOBAL = 1, // Global symbol, visible to all object files being combined
170 STB_WEAK = 2, // Weak symbol, like global but lower-precedence
171 STB_LOPROC = 13, // Lowest processor-specific binding type
172 STB_HIPROC = 15 // Highest processor-specific binding type
177 STT_NOTYPE = 0, // Symbol's type is not specified
178 STT_OBJECT = 1, // Symbol is a data object (variable, array, etc.)
179 STT_FUNC = 2, // Symbol is executable code (function, etc.)
180 STT_SECTION = 3, // Symbol refers to a section
181 STT_FILE = 4, // Local, absolute symbol that refers to a file
182 STT_LOPROC = 13, // Lowest processor-specific symbol type
183 STT_HIPROC = 15 // Highest processor-specific symbol type
186 // Relocation entry, without explicit addend.
188 Elf32_Addr r_offset; // Location (file byte offset, or program virtual addr)
189 Elf32_Word r_info; // Symbol table index and type of relocation to apply
191 // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
192 // and ELF32_R_INFO macros defined in the ELF specification:
193 Elf32_Word getSymbol () const { return (r_info >> 8); }
194 unsigned char getType () const { return (unsigned char) (r_info & 0x0ff); }
195 void setSymbol (Elf32_Word s) const { setSymbolAndType (s, getType ()); }
196 void setType (unsigned char t) const { setSymbolAndType (getSymbol(), t); }
197 void setSymbolAndType (Elf32_Word s, unsigned char t) {
198 r_info = (s << 8) + t;
202 // Relocation entry with explicit addend.
204 Elf32_Addr r_offset; // Location (file byte offset, or program virtual addr)
205 Elf32_Word r_info; // Symbol table index and type of relocation to apply
206 Elf32_Sword r_addend; // Compute value for relocatable field by adding this
208 // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE,
209 // and ELF32_R_INFO macros defined in the ELF specification:
210 Elf32_Word getSymbol () const { return (r_info >> 8); }
211 unsigned char getType () const { return (unsigned char) (r_info & 0x0ff); }
212 void setSymbol (Elf32_Word s) const { setSymbolAndType (s, getType ()); }
213 void setType (unsigned char t) const { setSymbolAndType (getSymbol(), t); }
214 void setSymbolAndType (Elf32_Word s, unsigned char t) {
215 r_info = (s << 8) + t;
221 Elf32_Word p_type; // Type of segment
222 Elf32_Off p_offset; // File offset where segment is located, in bytes
223 Elf32_Addr p_vaddr; // Virtual address of beginning of segment
224 Elf32_Addr p_paddr; // Physical address of beginning of segment (OS-specific)
225 Elf32_Word p_filesz; // Num. of bytes in file image of segment (may be zero)
226 Elf32_Word p_memsz; // Num. of bytes in mem image of segment (may be zero)
227 Elf32_Word p_flags; // Segment flags
228 Elf32_Word p_align; // Segment alignment constraint
232 PT_NULL = 0, // Unused segment.
233 PT_LOAD = 1, // Loadable segment.
234 PT_DYNAMIC = 2, // Dynamic linking information.
235 PT_INTERP = 3, // Interpreter pathname.
236 PT_NOTE = 4, // Auxiliary information.
237 PT_SHLIB = 5, // Reserved.
238 PT_PHDR = 6, // The program header table itself.
239 PT_LOPROC = 0x70000000, // Lowest processor-specific program hdr entry type.
240 PT_HIPROC = 0x7fffffff // Highest processor-specific program hdr entry type.
243 } // end namespace ELF
245 } // end namespace llvm