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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/BinaryFormat/ELF.h"
15 : #include "llvm/MC/MCObjectWriter.h"
16 : #include "llvm/MC/MCSectionELF.h"
17 : #include "llvm/Support/Casting.h"
18 : #include "llvm/Support/raw_ostream.h"
19 : #include <cstdint>
20 : #include <vector>
21 :
22 : namespace llvm {
23 :
24 : class MCAssembler;
25 : class MCContext;
26 : class MCFixup;
27 : class MCObjectWriter;
28 : class MCSymbol;
29 : class MCSymbolELF;
30 : class MCValue;
31 :
32 : struct ELFRelocationEntry {
33 : uint64_t Offset; // Where is the relocation.
34 : const MCSymbolELF *Symbol; // The symbol to relocate with.
35 : unsigned Type; // The type of the relocation.
36 : uint64_t Addend; // The addend to use.
37 : const MCSymbolELF *OriginalSymbol; // The original value of Symbol if we changed it.
38 : uint64_t OriginalAddend; // The original value of addend.
39 :
40 : ELFRelocationEntry(uint64_t Offset, const MCSymbolELF *Symbol, unsigned Type,
41 : uint64_t Addend, const MCSymbolELF *OriginalSymbol,
42 : uint64_t OriginalAddend)
43 5068416 : : Offset(Offset), Symbol(Symbol), Type(Type), Addend(Addend),
44 5068416 : OriginalSymbol(OriginalSymbol), OriginalAddend(OriginalAddend) {}
45 :
46 : void print(raw_ostream &Out) const {
47 : Out << "Off=" << Offset << ", Sym=" << Symbol << ", Type=" << Type
48 : << ", Addend=" << Addend << ", OriginalSymbol=" << OriginalSymbol
49 : << ", OriginalAddend=" << OriginalAddend;
50 : }
51 :
52 : void dump() const { print(errs()); }
53 : };
54 :
55 : class MCELFObjectTargetWriter : public MCObjectTargetWriter {
56 : const uint8_t OSABI;
57 : const uint16_t EMachine;
58 : const unsigned HasRelocationAddend : 1;
59 : const unsigned Is64Bit : 1;
60 :
61 : protected:
62 : MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_, uint16_t EMachine_,
63 : bool HasRelocationAddend);
64 :
65 : public:
66 0 : virtual ~MCELFObjectTargetWriter() = default;
67 :
68 30760 : virtual Triple::ObjectFormatType getFormat() const { return Triple::ELF; }
69 : static bool classof(const MCObjectTargetWriter *W) {
70 : return W->getFormat() == Triple::ELF;
71 : }
72 :
73 : static uint8_t getOSABI(Triple::OSType OSType) {
74 : switch (OSType) {
75 : case Triple::CloudABI:
76 : return ELF::ELFOSABI_CLOUDABI;
77 : case Triple::HermitCore:
78 : return ELF::ELFOSABI_STANDALONE;
79 : case Triple::PS4:
80 : case Triple::FreeBSD:
81 : return ELF::ELFOSABI_FREEBSD;
82 : default:
83 : return ELF::ELFOSABI_NONE;
84 : }
85 : }
86 :
87 : virtual unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
88 : const MCFixup &Fixup, bool IsPCRel) const = 0;
89 :
90 : virtual bool needsRelocateWithSymbol(const MCSymbol &Sym,
91 : unsigned Type) const;
92 :
93 : virtual void sortRelocs(const MCAssembler &Asm,
94 : std::vector<ELFRelocationEntry> &Relocs);
95 :
96 : virtual void addTargetSectionFlags(MCContext &Ctx, MCSectionELF &Sec);
97 :
98 : /// \name Accessors
99 : /// @{
100 0 : uint8_t getOSABI() const { return OSABI; }
101 0 : uint16_t getEMachine() const { return EMachine; }
102 11365255 : bool hasRelocationAddend() const { return HasRelocationAddend; }
103 12291305 : bool is64Bit() const { return Is64Bit; }
104 : /// @}
105 :
106 : // Instead of changing everyone's API we pack the N64 Type fields
107 : // into the existing 32 bit data unsigned.
108 : #define R_TYPE_SHIFT 0
109 : #define R_TYPE_MASK 0xffffff00
110 : #define R_TYPE2_SHIFT 8
111 : #define R_TYPE2_MASK 0xffff00ff
112 : #define R_TYPE3_SHIFT 16
113 : #define R_TYPE3_MASK 0xff00ffff
114 : #define R_SSYM_SHIFT 24
115 : #define R_SSYM_MASK 0x00ffffff
116 :
117 : // N64 relocation type accessors
118 0 : uint8_t getRType(uint32_t Type) const {
119 10346 : return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff);
120 : }
121 0 : uint8_t getRType2(uint32_t Type) const {
122 11447 : return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff);
123 : }
124 0 : uint8_t getRType3(uint32_t Type) const {
125 11447 : return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff);
126 : }
127 0 : uint8_t getRSsym(uint32_t Type) const {
128 10346 : return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff);
129 : }
130 :
131 : // N64 relocation type setting
132 0 : unsigned setRType(unsigned Value, unsigned Type) const {
133 0 : return ((Type & R_TYPE_MASK) | ((Value & 0xff) << R_TYPE_SHIFT));
134 : }
135 0 : unsigned setRType2(unsigned Value, unsigned Type) const {
136 0 : return (Type & R_TYPE2_MASK) | ((Value & 0xff) << R_TYPE2_SHIFT);
137 : }
138 0 : unsigned setRType3(unsigned Value, unsigned Type) const {
139 0 : return (Type & R_TYPE3_MASK) | ((Value & 0xff) << R_TYPE3_SHIFT);
140 : }
141 : unsigned setRSsym(unsigned Value, unsigned Type) const {
142 : return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT);
143 : }
144 : };
145 :
146 : /// Construct a new ELF writer instance.
147 : ///
148 : /// \param MOTW - The target specific ELF writer subclass.
149 : /// \param OS - The stream to write to.
150 : /// \returns The constructed object writer.
151 : std::unique_ptr<MCObjectWriter>
152 : createELFObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,
153 : raw_pwrite_stream &OS, bool IsLittleEndian);
154 :
155 : std::unique_ptr<MCObjectWriter>
156 : createELFDwoObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,
157 : raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS,
158 : bool IsLittleEndian);
159 :
160 : } // end namespace llvm
161 :
162 : #endif // LLVM_MC_MCELFOBJECTWRITER_H
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