1//===-- llvm/MC/MCELFObjectWriter.h - ELF Object Writer ---------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_MC_MCELFOBJECTWRITER_H
11#define LLVM_MC_MCELFOBJECTWRITER_H
12
13#include "llvm/ADT/Triple.h"
14#include "llvm/Support/DataTypes.h"
15#include "llvm/Support/ELF.h"
16#include <vector>
17
18namespace llvm {
19class MCAssembler;
20class MCFixup;
21class MCFragment;
22class MCObjectWriter;
23class MCSectionData;
24class MCSymbol;
25class MCValue;
26
27class MCELFObjectTargetWriter {
28  const uint8_t OSABI;
29  const uint16_t EMachine;
30  const unsigned HasRelocationAddend : 1;
31  const unsigned Is64Bit : 1;
32  const unsigned IsN64 : 1;
33
34protected:
35
36  MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_,
37                          uint16_t EMachine_,  bool HasRelocationAddend,
38                          bool IsN64=false);
39
40public:
41  static uint8_t getOSABI(Triple::OSType OSType) {
42    switch (OSType) {
43      case Triple::FreeBSD:
44        return ELF::ELFOSABI_FREEBSD;
45      case Triple::Linux:
46        return ELF::ELFOSABI_LINUX;
47      default:
48        return ELF::ELFOSABI_NONE;
49    }
50  }
51
52  virtual ~MCELFObjectTargetWriter() {}
53
54  virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
55                                bool IsPCRel) const = 0;
56
57  virtual bool needsRelocateWithSymbol(unsigned Type) const;
58
59  /// @name Accessors
60  /// @{
61  uint8_t getOSABI() const { return OSABI; }
62  uint16_t getEMachine() const { return EMachine; }
63  bool hasRelocationAddend() const { return HasRelocationAddend; }
64  bool is64Bit() const { return Is64Bit; }
65  bool isN64() const { return IsN64; }
66  /// @}
67
68  // Instead of changing everyone's API we pack the N64 Type fields
69  // into the existing 32 bit data unsigned.
70#define R_TYPE_SHIFT 0
71#define R_TYPE_MASK 0xffffff00
72#define R_TYPE2_SHIFT 8
73#define R_TYPE2_MASK 0xffff00ff
74#define R_TYPE3_SHIFT 16
75#define R_TYPE3_MASK 0xff00ffff
76#define R_SSYM_SHIFT 24
77#define R_SSYM_MASK 0x00ffffff
78
79  // N64 relocation type accessors
80  uint8_t getRType(uint32_t Type) const {
81    return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff);
82  }
83  uint8_t getRType2(uint32_t Type) const {
84    return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff);
85  }
86  uint8_t getRType3(uint32_t Type) const {
87    return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff);
88  }
89  uint8_t getRSsym(uint32_t Type) const {
90    return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff);
91  }
92
93  // N64 relocation type setting
94  unsigned setRType(unsigned Value, unsigned Type) const {
95    return ((Type & R_TYPE_MASK) | ((Value & 0xff) << R_TYPE_SHIFT));
96  }
97  unsigned setRType2(unsigned Value, unsigned Type) const {
98    return (Type & R_TYPE2_MASK) | ((Value & 0xff) << R_TYPE2_SHIFT);
99  }
100  unsigned setRType3(unsigned Value, unsigned Type) const {
101    return (Type & R_TYPE3_MASK) | ((Value & 0xff) << R_TYPE3_SHIFT);
102  }
103  unsigned setRSsym(unsigned Value, unsigned Type) const {
104    return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT);
105  }
106};
107
108/// \brief Construct a new ELF writer instance.
109///
110/// \param MOTW - The target specific ELF writer subclass.
111/// \param OS - The stream to write to.
112/// \returns The constructed object writer.
113MCObjectWriter *createELFObjectWriter(MCELFObjectTargetWriter *MOTW,
114                                      raw_ostream &OS, bool IsLittleEndian);
115} // End llvm namespace
116
117#endif
118