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