// 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.
+// 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/GlobalVariable.h"
+#include "llvm/CodeGen/BinaryObject.h"
#include "llvm/CodeGen/MachineRelocation.h"
#include "llvm/Support/DataTypes.h"
#include <cstring>
namespace llvm {
- class GlobalVariable;
+ class BinaryObject;
// Identification Indexes
enum {
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
};
- struct ELFHeader {
- // e_machine - This field is the target specific value to emit as the
- // e_machine member of the ELF header.
- unsigned short e_machine;
-
- // e_flags - The machine flags for the target. This defaults to zero.
- unsigned e_flags;
-
- // e_size - Holds the ELF header's size in bytes
- unsigned e_ehsize;
-
- // Endianess and ELF Class (64 or 32 bits)
- unsigned ByteOrder;
- unsigned ElfClass;
-
- unsigned getByteOrder() const { return ByteOrder; }
- unsigned getElfClass() const { return ElfClass; }
- unsigned getSize() const { return e_ehsize; }
- unsigned getMachine() const { return e_machine; }
- unsigned getFlags() const { return e_flags; }
-
- ELFHeader(unsigned short machine, unsigned flags,
- bool is64Bit, bool isLittleEndian)
- : e_machine(machine), e_flags(flags) {
- ElfClass = is64Bit ? ELFCLASS64 : ELFCLASS32;
- ByteOrder = isLittleEndian ? ELFDATA2LSB : ELFDATA2MSB;
- e_ehsize = is64Bit ? 64 : 52;
- }
- };
-
/// 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 {
-
+ class ELFSection : public BinaryObject {
+ public:
// 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;
+ 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 - Auxillary information.
+ unsigned Align; // sh_addralign - Alignment of section.
+ unsigned EntSize; // sh_entsize - Size of entries in the section e
// Section Header Flags
enum {
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_LOPROC = 0x70000000, // Lowest processor arch-specific type.
+ SHT_HIPROC = 0x7fffffff, // Highest processor arch-specific type.
SHT_LOUSER = 0x80000000, // Lowest type reserved for applications.
SHT_HIUSER = 0xffffffff // Highest type reserved for applications.
};
/// 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;
-
- /// Relocations - The relocations that we have encountered so far in this
- /// section that we will need to convert to Elf relocation entries when
- /// the file is written.
- std::vector<MachineRelocation> Relocations;
-
- /// Section Header Size
- static unsigned getSectionHdrSize(bool is64Bit)
- { return is64Bit ? 64 : 40; }
-
- 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) {}
+ 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) {}
};
/// 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.
+ // The global value this corresponds to. Global symbols can be on of the
+ // 3 types : if this symbol has a zero initializer, it is common or should
+ // be placed in bss section otherwise it's a constant.
+ const GlobalValue *GV;
+ bool IsCommon;
+ bool IsBss;
+ bool IsConstant;
// ELF specific fields
unsigned NameIdx; // Index in .strtab of name, once emitted.
STT_FILE = 4
};
- ELFSym(const GlobalValue *gv) : GV(gv), NameIdx(0), Value(0),
- Size(0), Info(0), Other(0),
- SectionIdx(ELFSection::SHN_UNDEF) {}
+ enum {
+ STV_DEFAULT = 0, // Visibility is specified by binding type
+ STV_INTERNAL = 1, // Defined by processor supplements
+ STV_HIDDEN = 2, // Not visible to other components
+ STV_PROTECTED = 3 // Visible in other components but not preemptable
+ };
- void SetBind(unsigned X) {
+ ELFSym(const GlobalValue *gv) : GV(gv), IsCommon(false), IsBss(false),
+ IsConstant(false), NameIdx(0), Value(0),
+ Size(0), Info(0), Other(STV_DEFAULT),
+ SectionIdx(ELFSection::SHN_UNDEF) {
+ if (!GV)
+ return;
+
+ switch (GV->getVisibility()) {
+ default:
+ assert(0 && "unknown visibility type");
+ case GlobalValue::DefaultVisibility:
+ Other = STV_DEFAULT;
+ break;
+ case GlobalValue::HiddenVisibility:
+ Other = STV_HIDDEN;
+ break;
+ case GlobalValue::ProtectedVisibility:
+ Other = STV_PROTECTED;
+ break;
+ }
+ }
+
+ unsigned getBind() {
+ return (Info >> 4) & 0xf;
+ }
+
+ void setBind(unsigned X) {
assert(X == (X & 0xF) && "Bind value out of range!");
Info = (Info & 0x0F) | (X << 4);
}
- void SetType(unsigned X) {
+ void setType(unsigned X) {
assert(X == (X & 0xF) && "Type value out of range!");
Info = (Info & 0xF0) | X;
}
};
+ /// 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
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