| //===-- 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 is based on HP/Intel definition of the |
| // ELF-64 object file format document, Version 1.5 Draft 2 May 27, 1998 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef CODEGEN_ELF_H |
| #define CODEGEN_ELF_H |
| |
| #include "llvm/CodeGen/BinaryObject.h" |
| #include "llvm/CodeGen/MachineRelocation.h" |
| #include "llvm/Support/ELF.h" |
| #include "llvm/Support/DataTypes.h" |
| |
| namespace llvm { |
| class GlobalValue; |
| |
| /// 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 { |
| |
| // ELF symbols are related to llvm ones by being one of the two llvm |
| // types, for the other ones (section, file, func) a null pointer is |
| // assumed by default. |
| union { |
| const GlobalValue *GV; // If this is a pointer to a GV |
| const char *Ext; // If this is a pointer to a named symbol |
| } Source; |
| |
| // Describes from which source type this ELF symbol comes from, |
| // they can be GlobalValue, ExternalSymbol or neither. |
| enum { |
| isGV, // The Source.GV field is valid. |
| isExtSym, // The Source.ExtSym field is valid. |
| isOther // Not a GlobalValue or External Symbol |
| }; |
| unsigned SourceType; |
| |
| bool isGlobalValue() const { return SourceType == isGV; } |
| bool isExternalSym() const { return SourceType == isExtSym; } |
| |
| // getGlobalValue - If this is a global value which originated the |
| // elf symbol, return a reference to it. |
| const GlobalValue *getGlobalValue() const { |
| assert(SourceType == isGV && "This is not a global value"); |
| return Source.GV; |
| } |
| |
| // getExternalSym - If this is an external symbol which originated the |
| // elf symbol, return a reference to it. |
| const char *getExternalSymbol() const { |
| assert(SourceType == isExtSym && "This is not an external symbol"); |
| return Source.Ext; |
| } |
| |
| // getGV - From a global value return a elf symbol to represent it |
| static ELFSym *getGV(const GlobalValue *GV, unsigned Bind, |
| unsigned Type, unsigned Visibility) { |
| ELFSym *Sym = new ELFSym(); |
| Sym->Source.GV = GV; |
| Sym->setBind(Bind); |
| Sym->setType(Type); |
| Sym->setVisibility(Visibility); |
| Sym->SourceType = isGV; |
| return Sym; |
| } |
| |
| // getExtSym - Create and return an elf symbol to represent an |
| // external symbol |
| static ELFSym *getExtSym(const char *Ext) { |
| ELFSym *Sym = new ELFSym(); |
| Sym->Source.Ext = Ext; |
| Sym->setBind(ELF::STB_GLOBAL); |
| Sym->setType(ELF::STT_NOTYPE); |
| Sym->setVisibility(ELF::STV_DEFAULT); |
| Sym->SourceType = isExtSym; |
| return Sym; |
| } |
| |
| // getSectionSym - Returns a elf symbol to represent an elf section |
| static ELFSym *getSectionSym() { |
| ELFSym *Sym = new ELFSym(); |
| Sym->setBind(ELF::STB_LOCAL); |
| Sym->setType(ELF::STT_SECTION); |
| Sym->setVisibility(ELF::STV_DEFAULT); |
| Sym->SourceType = isOther; |
| return Sym; |
| } |
| |
| // getFileSym - Returns a elf symbol to represent the module identifier |
| static ELFSym *getFileSym() { |
| ELFSym *Sym = new ELFSym(); |
| Sym->setBind(ELF::STB_LOCAL); |
| Sym->setType(ELF::STT_FILE); |
| Sym->setVisibility(ELF::STV_DEFAULT); |
| Sym->SectionIdx = 0xfff1; // ELFSection::SHN_ABS; |
| Sym->SourceType = isOther; |
| return Sym; |
| } |
| |
| // getUndefGV - Returns a STT_NOTYPE symbol |
| static ELFSym *getUndefGV(const GlobalValue *GV, unsigned Bind) { |
| ELFSym *Sym = new ELFSym(); |
| Sym->Source.GV = GV; |
| Sym->setBind(Bind); |
| Sym->setType(ELF::STT_NOTYPE); |
| Sym->setVisibility(ELF::STV_DEFAULT); |
| Sym->SectionIdx = 0; //ELFSection::SHN_UNDEF; |
| Sym->SourceType = isGV; |
| return Sym; |
| } |
| |
| // 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; |
| |
| // Symbol index into the Symbol table |
| unsigned SymTabIdx; |
| |
| ELFSym() : SourceType(isOther), NameIdx(0), Value(0), |
| Size(0), Info(0), Other(ELF::STV_DEFAULT), SectionIdx(0), |
| SymTabIdx(0) {} |
| |
| unsigned getBind() const { return (Info >> 4) & 0xf; } |
| unsigned getType() const { return Info & 0xf; } |
| bool isLocalBind() const { return getBind() == ELF::STB_LOCAL; } |
| bool isFileType() const { return getType() == ELF::STT_FILE; } |
| |
| 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; |
| } |
| |
| void setVisibility(unsigned V) { |
| assert(V == (V & 0x3) && "Visibility value out of range!"); |
| Other = V; |
| } |
| }; |
| |
| /// 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. |
| class ELFSection : public BinaryObject { |
| public: |
| // ELF specific fields |
| unsigned NameIdx; // sh_name - .shstrtab idx of name, once emitted. |
| unsigned Type; // sh_type - Section contents & semantics |
| unsigned Flags; // sh_flags - Section flags. |
| uint64_t Addr; // sh_addr - The mem addr this section is in. |
| unsigned Offset; // sh_offset - Offset from the file start |
| unsigned Size; // sh_size - The section size. |
| unsigned Link; // sh_link - Section header table index link. |
| unsigned Info; // sh_info - Auxiliary information. |
| unsigned Align; // sh_addralign - Alignment of section. |
| unsigned EntSize; // sh_entsize - Size of entries in the section e |
| |
| /// SectionIdx - The number of the section in the Section Table. |
| unsigned short SectionIdx; |
| |
| /// Sym - The symbol to represent this section if it has one. |
| ELFSym *Sym; |
| |
| /// getSymIndex - Returns the symbol table index of the symbol |
| /// representing this section. |
| unsigned getSymbolTableIndex() const { |
| assert(Sym && "section not present in the symbol table"); |
| return Sym->SymTabIdx; |
| } |
| |
| ELFSection(const std::string &name, bool isLittleEndian, bool is64Bit) |
| : BinaryObject(name, isLittleEndian, is64Bit), Type(0), Flags(0), Addr(0), |
| Offset(0), Size(0), Link(0), Info(0), Align(0), EntSize(0), Sym(0) {} |
| }; |
| |
| /// ELFRelocation - This class contains all the information necessary to |
| /// to generate any 32-bit or 64-bit ELF relocation entry. |
| class ELFRelocation { |
| uint64_t r_offset; // offset in the section of the object this applies to |
| uint32_t r_symidx; // symbol table index of the symbol to use |
| uint32_t r_type; // machine specific relocation type |
| int64_t r_add; // explicit relocation addend |
| bool r_rela; // if true then the addend is part of the entry |
| // otherwise the addend is at the location specified |
| // by r_offset |
| public: |
| uint64_t getInfo(bool is64Bit) const { |
| if (is64Bit) |
| return ((uint64_t)r_symidx << 32) + ((uint64_t)r_type & 0xFFFFFFFFL); |
| else |
| return (r_symidx << 8) + (r_type & 0xFFL); |
| } |
| |
| uint64_t getOffset() const { return r_offset; } |
| int64_t getAddend() const { return r_add; } |
| |
| ELFRelocation(uint64_t off, uint32_t sym, uint32_t type, |
| bool rela = true, int64_t addend = 0) : |
| r_offset(off), r_symidx(sym), r_type(type), |
| r_add(addend), r_rela(rela) {} |
| }; |
| |
| } // end namespace llvm |
| |
| #endif |