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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLD_MACHO_RELOCATIONS_H10#define LLD_MACHO_RELOCATIONS_H11 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, // invalid28 BYTE1 = 1 << 0, // 1 byte datum29 BYTE2 = 1 << 1, // 2 byte datum30 BYTE4 = 1 << 2, // 4 byte datum31 BYTE8 = 1 << 3, // 8 byte datum32 PCREL = 1 << 4, // Value is PC-relative offset33 ABSOLUTE = 1 << 5, // Value is an absolute address or fixed offset34 EXTERN = 1 << 6, // Can have an external symbol35 LOCAL = 1 << 7, // Can have a local symbol36 ADDEND = 1 << 8, // *_ADDEND paired prefix reloc37 SUBTRAHEND = 1 << 9, // *_SUBTRACTOR paired prefix reloc38 BRANCH = 1 << 10, // Value is branch target39 GOT = 1 << 11, // References a symbol in the Global Offset Table40 TLV = 1 << 12, // References a thread-local symbol41 LOAD = 1 << 13, // Relaxable indirect load42 POINTER = 1 << 14, // Non-relaxable indirect load (pointer is taken)43 UNSIGNED = 1 << 15, // *_UNSIGNED relocs44 LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue*/ (1 << 16) - 1),45};46// Note: SUBTRACTOR always pairs with UNSIGNED (a delta between two symbols).47 48struct RelocAttrs {49 llvm::StringRef name;50 RelocAttrBits bits;51 bool hasAttr(RelocAttrBits b) const { return (bits & b) == b; }52};53 54struct Reloc {55 uint8_t type = llvm::MachO::GENERIC_RELOC_INVALID;56 bool pcrel = false;57 uint8_t length = 0;58 // The offset from the start of the subsection that this relocation belongs59 // to.60 uint32_t offset = 0;61 // Adding this offset to the address of the referent symbol or subsection62 // gives the destination that this relocation refers to.63 int64_t addend = 0;64 llvm::PointerUnion<Symbol *, InputSection *> referent = nullptr;65 66 Reloc() = default;67 68 Reloc(uint8_t type, bool pcrel, uint8_t length, uint32_t offset,69 int64_t addend, llvm::PointerUnion<Symbol *, InputSection *> referent)70 : type(type), pcrel(pcrel), length(length), offset(offset),71 addend(addend), referent(referent) {}72 73 InputSection *getReferentInputSection() const;74 75 // Must point to an offset within a CStringInputSection or a76 // ConcatInputSection.77 llvm::StringRef getReferentString() const;78};79 80bool validateSymbolRelocation(const Symbol *, const InputSection *,81 const Reloc &);82 83/*84 * v: The value the relocation is attempting to encode85 * bits: The number of bits actually available to encode this relocation86 */87void reportRangeError(void *loc, const Reloc &, const llvm::Twine &v,88 uint8_t bits, int64_t min, uint64_t max);89 90struct SymbolDiagnostic {91 const Symbol *symbol;92 llvm::StringRef reason;93};94 95void reportRangeError(void *loc, SymbolDiagnostic, const llvm::Twine &v,96 uint8_t bits, int64_t min, uint64_t max);97 98template <typename Diagnostic>99inline void checkInt(void *loc, Diagnostic d, int64_t v, int bits) {100 if (v != llvm::SignExtend64(v, bits))101 reportRangeError(loc, d, llvm::Twine(v), bits, llvm::minIntN(bits),102 llvm::maxIntN(bits));103}104 105template <typename Diagnostic>106inline void checkUInt(void *loc, Diagnostic d, uint64_t v, int bits) {107 if ((v >> bits) != 0)108 reportRangeError(loc, d, llvm::Twine(v), bits, 0, llvm::maxUIntN(bits));109}110 111inline void writeAddress(uint8_t *loc, uint64_t addr, uint8_t length) {112 switch (length) {113 case 2:114 llvm::support::endian::write32le(loc, addr);115 break;116 case 3:117 llvm::support::endian::write64le(loc, addr);118 break;119 default:120 llvm_unreachable("invalid r_length");121 }122}123 124InputSection *offsetToInputSection(uint64_t *);125 126extern const RelocAttrs invalidRelocAttrs;127 128} // namespace lld::Macho129 130#endif131