Remove elf specific info from ELFWriter.h to Elf.h. Code cleanup and more comments added
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72982 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ELF.h b/lib/CodeGen/ELF.h
new file mode 100644
index 0000000..bf43622
--- /dev/null
+++ b/lib/CodeGen/ELF.h
@@ -0,0 +1,186 @@
+//===-- 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