1//===- Relocations.h --------------------------------------------*- C++ -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#ifndef LLD_MACHO_RELOCATIONS_H 10#define LLD_MACHO_RELOCATIONS_H 11 12#include "llvm/ADT/BitmaskEnum.h" 13#include "llvm/ADT/PointerUnion.h" 14#include "llvm/BinaryFormat/MachO.h" 15#include "llvm/Support/Endian.h" 16 17#include <cstddef> 18#include <cstdint> 19 20namespace lld::macho { 21LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE(); 22 23class Symbol; 24class InputSection; 25 26enum class RelocAttrBits { 27 _0 = 0, // invalid 28 PCREL = 1 << 0, // Value is PC-relative offset 29 ABSOLUTE = 1 << 1, // Value is an absolute address or fixed offset 30 BYTE4 = 1 << 2, // 4 byte datum 31 BYTE8 = 1 << 3, // 8 byte datum 32 EXTERN = 1 << 4, // Can have an external symbol 33 LOCAL = 1 << 5, // Can have a local symbol 34 ADDEND = 1 << 6, // *_ADDEND paired prefix reloc 35 SUBTRAHEND = 1 << 7, // *_SUBTRACTOR paired prefix reloc 36 BRANCH = 1 << 8, // Value is branch target 37 GOT = 1 << 9, // References a symbol in the Global Offset Table 38 TLV = 1 << 10, // References a thread-local symbol 39 LOAD = 1 << 11, // Relaxable indirect load 40 POINTER = 1 << 12, // Non-relaxable indirect load (pointer is taken) 41 UNSIGNED = 1 << 13, // *_UNSIGNED relocs 42 LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue*/ (1 << 14) - 1), 43}; 44// Note: SUBTRACTOR always pairs with UNSIGNED (a delta between two symbols). 45 46struct RelocAttrs { 47 llvm::StringRef name; 48 RelocAttrBits bits; 49 bool hasAttr(RelocAttrBits b) const { return (bits & b) == b; } 50}; 51 52struct Reloc { 53 uint8_t type = llvm::MachO::GENERIC_RELOC_INVALID; 54 bool pcrel = false; 55 uint8_t length = 0; 56 // The offset from the start of the subsection that this relocation belongs 57 // to. 58 uint32_t offset = 0; 59 // Adding this offset to the address of the referent symbol or subsection 60 // gives the destination that this relocation refers to. 61 int64_t addend = 0; 62 llvm::PointerUnion<Symbol *, InputSection *> referent = nullptr; 63 64 Reloc() = default; 65 66 Reloc(uint8_t type, bool pcrel, uint8_t length, uint32_t offset, 67 int64_t addend, llvm::PointerUnion<Symbol *, InputSection *> referent) 68 : type(type), pcrel(pcrel), length(length), offset(offset), 69 addend(addend), referent(referent) {} 70 71 InputSection *getReferentInputSection() const; 72}; 73 74bool validateSymbolRelocation(const Symbol *, const InputSection *, 75 const Reloc &); 76 77/* 78 * v: The value the relocation is attempting to encode 79 * bits: The number of bits actually available to encode this relocation 80 */ 81void reportRangeError(void *loc, const Reloc &, const llvm::Twine &v, 82 uint8_t bits, int64_t min, uint64_t max); 83 84struct SymbolDiagnostic { 85 const Symbol *symbol; 86 llvm::StringRef reason; 87}; 88 89void reportRangeError(void *loc, SymbolDiagnostic, const llvm::Twine &v, 90 uint8_t bits, int64_t min, uint64_t max); 91 92template <typename Diagnostic> 93inline void checkInt(void *loc, Diagnostic d, int64_t v, int bits) { 94 if (v != llvm::SignExtend64(v, bits)) 95 reportRangeError(loc, d, llvm::Twine(v), bits, llvm::minIntN(bits), 96 llvm::maxIntN(bits)); 97} 98 99template <typename Diagnostic> 100inline void checkUInt(void *loc, Diagnostic d, uint64_t v, int bits) { 101 if ((v >> bits) != 0) 102 reportRangeError(loc, d, llvm::Twine(v), bits, 0, llvm::maxUIntN(bits)); 103} 104 105inline void writeAddress(uint8_t *loc, uint64_t addr, uint8_t length) { 106 switch (length) { 107 case 2: 108 llvm::support::endian::write32le(loc, addr); 109 break; 110 case 3: 111 llvm::support::endian::write64le(loc, addr); 112 break; 113 default: 114 llvm_unreachable("invalid r_length"); 115 } 116} 117 118InputSection *offsetToInputSection(uint64_t *); 119 120extern const RelocAttrs invalidRelocAttrs; 121 122} // namespace lld::Macho 123 124#endif 125