freebsd-dev/lib/CodeGen/ELF.h

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//===-- lib/CodeGen/ELF.h - ELF constants and data structures ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header contains common, non-processor-specific data structures and
// constants for the ELF file format.
//
// The details of the ELF32 bits in this file are largely based on
// the Tool Interface Standard (TIS) Executable and Linking Format
// (ELF) Specification Version 1.2, May 1995. The ELF64 stuff is not
// standardized, as far as I can tell. It was largely based on information
// I found in OpenBSD header files.
//
//===----------------------------------------------------------------------===//
#ifndef CODEGEN_ELF_H
#define CODEGEN_ELF_H
#include "llvm/Support/DataTypes.h"
#include <cstring>
namespace llvm {
class GlobalVariable;
// Identification Indexes
enum {
EI_MAG0 = 0,
EI_MAG1 = 1,
EI_MAG2 = 2,
EI_MAG3 = 3
};
// File types
enum {
ET_NONE = 0, // No file type
ET_REL = 1, // Relocatable file
ET_EXEC = 2, // Executable file
ET_DYN = 3, // Shared object file
ET_CORE = 4, // Core file
ET_LOPROC = 0xff00, // Beginning of processor-specific codes
ET_HIPROC = 0xffff // Processor-specific
};
// Object file classes.
enum {
ELFCLASS32 = 1, // 32-bit object file
ELFCLASS64 = 2 // 64-bit object file
};
// Object file byte orderings.
enum {
ELFDATA2LSB = 1, // Little-endian object file
ELFDATA2MSB = 2 // Big-endian object file
};
// Versioning
enum {
EV_NONE = 0,
EV_CURRENT = 1
};
/// ELFSection - This struct contains information about each section that is
/// emitted to the file. This is eventually turned into the section header
/// table at the end of the file.
struct ELFSection {
// ELF specific fields
std::string Name; // Name of the section.
unsigned NameIdx; // Index in .shstrtab of name, once emitted.
unsigned Type;
unsigned Flags;
uint64_t Addr;
unsigned Offset;
unsigned Size;
unsigned Link;
unsigned Info;
unsigned Align;
unsigned EntSize;
// Section Header Flags
enum {
SHF_WRITE = 1 << 0, // Writable
SHF_ALLOC = 1 << 1, // Mapped into the process addr space
SHF_EXECINSTR = 1 << 2, // Executable
SHF_MERGE = 1 << 4, // Might be merged if equal
SHF_STRINGS = 1 << 5, // Contains null-terminated strings
SHF_INFO_LINK = 1 << 6, // 'sh_info' contains SHT index
SHF_LINK_ORDER = 1 << 7, // Preserve order after combining
SHF_OS_NONCONFORMING = 1 << 8, // nonstandard OS support required
SHF_GROUP = 1 << 9, // Section is a member of a group
SHF_TLS = 1 << 10 // Section holds thread-local data
};
// Section Types
enum {
SHT_NULL = 0, // No associated section (inactive entry).
SHT_PROGBITS = 1, // Program-defined contents.
SHT_SYMTAB = 2, // Symbol table.
SHT_STRTAB = 3, // String table.
SHT_RELA = 4, // Relocation entries; explicit addends.
SHT_HASH = 5, // Symbol hash table.
SHT_DYNAMIC = 6, // Information for dynamic linking.
SHT_NOTE = 7, // Information about the file.
SHT_NOBITS = 8, // Data occupies no space in the file.
SHT_REL = 9, // Relocation entries; no explicit addends.
SHT_SHLIB = 10, // Reserved.
SHT_DYNSYM = 11, // Symbol table.
SHT_LOPROC = 0x70000000, // Lowest processor architecture-specific type.
SHT_HIPROC = 0x7fffffff, // Highest processor architecture-specific type.
SHT_LOUSER = 0x80000000, // Lowest type reserved for applications.
SHT_HIUSER = 0xffffffff // Highest type reserved for applications.
};
// Special section indices.
enum {
SHN_UNDEF = 0, // Undefined, missing, irrelevant, or meaningless
SHN_LORESERVE = 0xff00, // Lowest reserved index
SHN_LOPROC = 0xff00, // Lowest processor-specific index
SHN_HIPROC = 0xff1f, // Highest processor-specific index
SHN_ABS = 0xfff1, // Symbol has absolute value; does not need relocation
SHN_COMMON = 0xfff2, // FORTRAN COMMON or C external global variables
SHN_HIRESERVE = 0xffff // Highest reserved index
};
/// SectionIdx - The number of the section in the Section Table.
unsigned short SectionIdx;
/// SectionData - The actual data for this section which we are building
/// up for emission to the file.
std::vector<unsigned char> SectionData;
ELFSection(const std::string &name)
: Name(name), Type(0), Flags(0), Addr(0), Offset(0), Size(0),
Link(0), Info(0), Align(0), EntSize(0) {}
};
/// ELFSym - This struct contains information about each symbol that is
/// added to logical symbol table for the module. This is eventually
/// turned into a real symbol table in the file.
struct ELFSym {
const GlobalValue *GV; // The global value this corresponds to.
// ELF specific fields
unsigned NameIdx; // Index in .strtab of name, once emitted.
uint64_t Value;
unsigned Size;
uint8_t Info;
uint8_t Other;
unsigned short SectionIdx;
enum {
STB_LOCAL = 0,
STB_GLOBAL = 1,
STB_WEAK = 2
};
enum {
STT_NOTYPE = 0,
STT_OBJECT = 1,
STT_FUNC = 2,
STT_SECTION = 3,
STT_FILE = 4
};
ELFSym(const GlobalValue *gv) : GV(gv), Value(0),
Size(0), Info(0), Other(0),
SectionIdx(ELFSection::SHN_UNDEF) {}
void SetBind(unsigned X) {
assert(X == (X & 0xF) && "Bind value out of range!");
Info = (Info & 0x0F) | (X << 4);
}
void SetType(unsigned X) {
assert(X == (X & 0xF) && "Type value out of range!");
Info = (Info & 0xF0) | X;
}
};
} // end namespace llvm
#endif