1 //===- lib/ReaderWriter/MachO/MachONormalizedFileBinaryUtils.h ------------===//
2 //
3 // The LLVM Linker
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 LLD_READER_WRITER_MACHO_NORMALIZED_FILE_BINARY_UTILS_H
11 #define LLD_READER_WRITER_MACHO_NORMALIZED_FILE_BINARY_UTILS_H
12
13 #include "MachONormalizedFile.h"
14 #include "lld/Common/LLVM.h"
15 #include "lld/Core/Error.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/BinaryFormat/MachO.h"
18 #include "llvm/Support/Casting.h"
19 #include "llvm/Support/Endian.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/Host.h"
22 #include "llvm/Support/LEB128.h"
23 #include <system_error>
24
25 namespace lld {
26 namespace mach_o {
27 namespace normalized {
28
29 class ByteBuffer {
30 public:
ByteBuffer()31 ByteBuffer() : _ostream(_bytes) { }
32
append_byte(uint8_t b)33 void append_byte(uint8_t b) {
34 _ostream << b;
35 }
append_uleb128(uint64_t value)36 void append_uleb128(uint64_t value) {
37 llvm::encodeULEB128(value, _ostream);
38 }
append_uleb128Fixed(uint64_t value,unsigned byteCount)39 void append_uleb128Fixed(uint64_t value, unsigned byteCount) {
40 unsigned min = llvm::getULEB128Size(value);
41 assert(min <= byteCount);
42 unsigned pad = byteCount - min;
43 llvm::encodeULEB128(value, _ostream, pad);
44 }
append_sleb128(int64_t value)45 void append_sleb128(int64_t value) {
46 llvm::encodeSLEB128(value, _ostream);
47 }
append_string(StringRef str)48 void append_string(StringRef str) {
49 _ostream << str;
50 append_byte(0);
51 }
align(unsigned alignment)52 void align(unsigned alignment) {
53 while ( (_ostream.tell() % alignment) != 0 )
54 append_byte(0);
55 }
size()56 size_t size() {
57 return _ostream.tell();
58 }
bytes()59 const uint8_t *bytes() {
60 return reinterpret_cast<const uint8_t*>(_ostream.str().data());
61 }
62
63 private:
64 SmallVector<char, 128> _bytes;
65 // Stream ivar must be after SmallVector ivar to construct properly.
66 llvm::raw_svector_ostream _ostream;
67 };
68
69 using namespace llvm::support::endian;
70 using llvm::sys::getSwappedBytes;
71
72 template<typename T>
read16(const T * loc,bool isBig)73 static inline uint16_t read16(const T *loc, bool isBig) {
74 assert((uint64_t)loc % alignof(T) == 0 && "invalid pointer alignment");
75 return isBig ? read16be(loc) : read16le(loc);
76 }
77
78 template<typename T>
read32(const T * loc,bool isBig)79 static inline uint32_t read32(const T *loc, bool isBig) {
80 assert((uint64_t)loc % alignof(T) == 0 && "invalid pointer alignment");
81 return isBig ? read32be(loc) : read32le(loc);
82 }
83
84 template<typename T>
read64(const T * loc,bool isBig)85 static inline uint64_t read64(const T *loc, bool isBig) {
86 assert((uint64_t)loc % alignof(T) == 0 && "invalid pointer alignment");
87 return isBig ? read64be(loc) : read64le(loc);
88 }
89
write16(uint8_t * loc,uint16_t value,bool isBig)90 inline void write16(uint8_t *loc, uint16_t value, bool isBig) {
91 if (isBig)
92 write16be(loc, value);
93 else
94 write16le(loc, value);
95 }
96
write32(uint8_t * loc,uint32_t value,bool isBig)97 inline void write32(uint8_t *loc, uint32_t value, bool isBig) {
98 if (isBig)
99 write32be(loc, value);
100 else
101 write32le(loc, value);
102 }
103
write64(uint8_t * loc,uint64_t value,bool isBig)104 inline void write64(uint8_t *loc, uint64_t value, bool isBig) {
105 if (isBig)
106 write64be(loc, value);
107 else
108 write64le(loc, value);
109 }
110
111 inline uint32_t
bitFieldExtract(uint32_t value,bool isBigEndianBigField,uint8_t firstBit,uint8_t bitCount)112 bitFieldExtract(uint32_t value, bool isBigEndianBigField, uint8_t firstBit,
113 uint8_t bitCount) {
114 const uint32_t mask = ((1<<bitCount)-1);
115 const uint8_t shift = isBigEndianBigField ? (32-firstBit-bitCount) : firstBit;
116 return (value >> shift) & mask;
117 }
118
119 inline void
bitFieldSet(uint32_t & bits,bool isBigEndianBigField,uint32_t newBits,uint8_t firstBit,uint8_t bitCount)120 bitFieldSet(uint32_t &bits, bool isBigEndianBigField, uint32_t newBits,
121 uint8_t firstBit, uint8_t bitCount) {
122 const uint32_t mask = ((1<<bitCount)-1);
123 assert((newBits & mask) == newBits);
124 const uint8_t shift = isBigEndianBigField ? (32-firstBit-bitCount) : firstBit;
125 bits &= ~(mask << shift);
126 bits |= (newBits << shift);
127 }
128
unpackRelocation(const llvm::MachO::any_relocation_info & r,bool isBigEndian)129 inline Relocation unpackRelocation(const llvm::MachO::any_relocation_info &r,
130 bool isBigEndian) {
131 uint32_t r0 = read32(&r.r_word0, isBigEndian);
132 uint32_t r1 = read32(&r.r_word1, isBigEndian);
133
134 Relocation result;
135 if (r0 & llvm::MachO::R_SCATTERED) {
136 // scattered relocation record always laid out like big endian bit field
137 result.offset = bitFieldExtract(r0, true, 8, 24);
138 result.scattered = true;
139 result.type = (RelocationInfoType)
140 bitFieldExtract(r0, true, 4, 4);
141 result.length = bitFieldExtract(r0, true, 2, 2);
142 result.pcRel = bitFieldExtract(r0, true, 1, 1);
143 result.isExtern = false;
144 result.value = r1;
145 result.symbol = 0;
146 } else {
147 result.offset = r0;
148 result.scattered = false;
149 result.type = (RelocationInfoType)
150 bitFieldExtract(r1, isBigEndian, 28, 4);
151 result.length = bitFieldExtract(r1, isBigEndian, 25, 2);
152 result.pcRel = bitFieldExtract(r1, isBigEndian, 24, 1);
153 result.isExtern = bitFieldExtract(r1, isBigEndian, 27, 1);
154 result.value = 0;
155 result.symbol = bitFieldExtract(r1, isBigEndian, 0, 24);
156 }
157 return result;
158 }
159
160
161 inline llvm::MachO::any_relocation_info
packRelocation(const Relocation & r,bool swap,bool isBigEndian)162 packRelocation(const Relocation &r, bool swap, bool isBigEndian) {
163 uint32_t r0 = 0;
164 uint32_t r1 = 0;
165
166 if (r.scattered) {
167 r1 = r.value;
168 bitFieldSet(r0, true, r.offset, 8, 24);
169 bitFieldSet(r0, true, r.type, 4, 4);
170 bitFieldSet(r0, true, r.length, 2, 2);
171 bitFieldSet(r0, true, r.pcRel, 1, 1);
172 bitFieldSet(r0, true, r.scattered, 0, 1); // R_SCATTERED
173 } else {
174 r0 = r.offset;
175 bitFieldSet(r1, isBigEndian, r.type, 28, 4);
176 bitFieldSet(r1, isBigEndian, r.isExtern, 27, 1);
177 bitFieldSet(r1, isBigEndian, r.length, 25, 2);
178 bitFieldSet(r1, isBigEndian, r.pcRel, 24, 1);
179 bitFieldSet(r1, isBigEndian, r.symbol, 0, 24);
180 }
181
182 llvm::MachO::any_relocation_info result;
183 result.r_word0 = swap ? getSwappedBytes(r0) : r0;
184 result.r_word1 = swap ? getSwappedBytes(r1) : r1;
185 return result;
186 }
187
getString16(const char s[16])188 inline StringRef getString16(const char s[16]) {
189 // The StringRef(const char *) constructor passes the const char * to
190 // strlen(), so we can't use this constructor here, because if there is no
191 // null terminator in s, then strlen() will read past the end of the array.
192 return StringRef(s, strnlen(s, 16));
193 }
194
setString16(StringRef str,char s[16])195 inline void setString16(StringRef str, char s[16]) {
196 memset(s, 0, 16);
197 memcpy(s, str.begin(), (str.size() > 16) ? 16: str.size());
198 }
199
200 // Implemented in normalizedToAtoms() and used by normalizedFromAtoms() so
201 // that the same table can be used to map mach-o sections to and from
202 // DefinedAtom::ContentType.
203 void relocatableSectionInfoForContentType(DefinedAtom::ContentType atomType,
204 StringRef &segmentName,
205 StringRef §ionName,
206 SectionType §ionType,
207 SectionAttr §ionAttrs,
208 bool &relocsToDefinedCanBeImplicit);
209
210 } // namespace normalized
211 } // namespace mach_o
212 } // namespace lld
213
214 #endif // LLD_READER_WRITER_MACHO_NORMALIZED_FILE_BINARY_UTILS_H
215