1 //===- Target.h -------------------------------------------------*- C++ -*-===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLD_ELF_TARGET_H
11 #define LLD_ELF_TARGET_H
14 #include "InputSection.h"
15 #include "llvm/Object/ELF.h"
18 std::string toString(uint32_t RelType);
26 virtual bool isPicRel(uint32_t Type) const { return true; }
27 virtual uint32_t getDynRel(uint32_t Type) const { return Type; }
28 virtual void writeGotPltHeader(uint8_t *Buf) const {}
29 virtual void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {};
30 virtual void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const;
31 virtual int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const;
33 // If lazy binding is supported, the first entry of the PLT has code
34 // to call the dynamic linker to resolve PLT entries the first time
35 // they are called. This function writes that code.
36 virtual void writePltHeader(uint8_t *Buf) const {}
38 virtual void writePlt(uint8_t *Buf, uint64_t GotEntryAddr,
39 uint64_t PltEntryAddr, int32_t Index,
40 unsigned RelOff) const {}
41 virtual void addPltHeaderSymbols(InputSectionBase *IS) const {}
42 virtual void addPltSymbols(InputSectionBase *IS, uint64_t Off) const {}
43 // Returns true if a relocation only uses the low bits of a value such that
44 // all those bits are in in the same page. For example, if the relocation
45 // only uses the low 12 bits in a system with 4k pages. If this is true, the
46 // bits will always have the same value at runtime and we don't have to emit
47 // a dynamic relocation.
48 virtual bool usesOnlyLowPageBits(uint32_t Type) const;
50 // Decide whether a Thunk is needed for the relocation from File
52 virtual bool needsThunk(RelExpr Expr, uint32_t RelocType,
53 const InputFile *File, const SymbolBody &S) const;
54 // Return true if we can reach Dst from Src with Relocation RelocType
55 virtual bool inBranchRange(uint32_t RelocType, uint64_t Src,
57 virtual RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
58 const uint8_t *Loc) const = 0;
59 virtual void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const = 0;
60 virtual ~TargetInfo();
62 unsigned TlsGdRelaxSkip = 1;
63 unsigned PageSize = 4096;
64 unsigned DefaultMaxPageSize = 4096;
66 // On FreeBSD x86_64 the first page cannot be mmaped.
67 // On Linux that is controled by vm.mmap_min_addr. At least on some x86_64
68 // installs that is 65536, so the first 15 pages cannot be used.
69 // Given that, the smallest value that can be used in here is 0x10000.
70 uint64_t DefaultImageBase = 0x10000;
72 // Offset of _GLOBAL_OFFSET_TABLE_ from base of .got section. Use -1 for
74 uint64_t GotBaseSymOff = 0;
80 uint32_t IRelativeRel;
83 uint32_t TlsModuleIndexRel;
84 uint32_t TlsOffsetRel;
85 unsigned GotEntrySize = 0;
86 unsigned GotPltEntrySize = 0;
87 unsigned PltEntrySize;
88 unsigned PltHeaderSize;
90 // At least on x86_64 positions 1 and 2 are used by the first plt entry
91 // to support lazy loading.
92 unsigned GotPltHeaderEntriesNum = 3;
94 // Set to 0 for variant 2
97 bool NeedsThunks = false;
99 // A 4-byte field corresponding to one or more trap instructions, used to pad
100 // executable OutputSections.
101 uint32_t TrapInstr = 0;
103 virtual RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
105 virtual void relaxGot(uint8_t *Loc, uint64_t Val) const;
106 virtual void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
107 virtual void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
108 virtual void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
109 virtual void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
112 TargetInfo *getAArch64TargetInfo();
113 TargetInfo *getAMDGPUTargetInfo();
114 TargetInfo *getARMTargetInfo();
115 TargetInfo *getAVRTargetInfo();
116 TargetInfo *getPPC64TargetInfo();
117 TargetInfo *getPPCTargetInfo();
118 TargetInfo *getSPARCV9TargetInfo();
119 TargetInfo *getX32TargetInfo();
120 TargetInfo *getX86TargetInfo();
121 TargetInfo *getX86_64TargetInfo();
122 template <class ELFT> TargetInfo *getMipsTargetInfo();
124 std::string getErrorLocation(const uint8_t *Loc);
126 uint64_t getPPC64TocBase();
127 uint64_t getAArch64Page(uint64_t Expr);
129 extern TargetInfo *Target;
130 TargetInfo *getTarget();
132 template <unsigned N>
133 static void checkInt(uint8_t *Loc, int64_t V, uint32_t Type) {
134 if (!llvm::isInt<N>(V))
135 error(getErrorLocation(Loc) + "relocation " + lld::toString(Type) +
139 template <unsigned N>
140 static void checkUInt(uint8_t *Loc, uint64_t V, uint32_t Type) {
141 if (!llvm::isUInt<N>(V))
142 error(getErrorLocation(Loc) + "relocation " + lld::toString(Type) +
146 template <unsigned N>
147 static void checkIntUInt(uint8_t *Loc, uint64_t V, uint32_t Type) {
148 if (!llvm::isInt<N>(V) && !llvm::isUInt<N>(V))
149 error(getErrorLocation(Loc) + "relocation " + lld::toString(Type) +
153 template <unsigned N>
154 static void checkAlignment(uint8_t *Loc, uint64_t V, uint32_t Type) {
155 if ((V & (N - 1)) != 0)
156 error(getErrorLocation(Loc) + "improper alignment for relocation " +
157 lld::toString(Type));