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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // TODO(simonb): Extend for 64-bit target libraries. | |
6 | |
7 #include "packer.h" | 5 #include "packer.h" |
8 | 6 |
9 #include <string.h> | |
10 #include <string> | |
11 #include <vector> | 7 #include <vector> |
12 | 8 |
13 #include "debug.h" | 9 #include "debug.h" |
| 10 #include "elf_traits.h" |
14 #include "leb128.h" | 11 #include "leb128.h" |
15 #include "run_length_encoder.h" | 12 #include "run_length_encoder.h" |
16 | 13 |
17 namespace relocation_packer { | 14 namespace relocation_packer { |
18 | 15 |
19 // Pack R_ARM_RELATIVE relocations into a run-length encoded packed | 16 // Pack ARM relative relocations into a run-length encoded packed |
20 // representation. | 17 // representation. |
21 void RelocationPacker::PackRelativeRelocations( | 18 void RelocationPacker::PackRelativeRelocations( |
22 const std::vector<Elf32_Rel>& relocations, | 19 const std::vector<ELF::Rel>& relocations, |
23 std::vector<uint8_t>* packed) { | 20 std::vector<uint8_t>* packed) { |
24 | 21 |
25 // Run-length encode. | 22 // Run-length encode. |
26 std::vector<Elf32_Word> packed_words; | 23 std::vector<ELF::Xword> packed_words; |
27 RelocationRunLengthCodec codec; | 24 RelocationRunLengthCodec codec; |
28 codec.Encode(relocations, &packed_words); | 25 codec.Encode(relocations, &packed_words); |
29 | 26 |
30 // If insufficient data to run-length encode, do nothing. | 27 // If insufficient data to run-length encode, do nothing. |
31 if (packed_words.empty()) | 28 if (packed_words.empty()) |
32 return; | 29 return; |
33 | 30 |
34 // LEB128 encode, with "APR1" prefix. | 31 // LEB128 encode, with "APR1" prefix. |
35 Leb128Encoder encoder; | 32 Leb128Encoder encoder; |
36 encoder.Enqueue('A'); | 33 encoder.Enqueue('A'); |
37 encoder.Enqueue('P'); | 34 encoder.Enqueue('P'); |
38 encoder.Enqueue('R'); | 35 encoder.Enqueue('R'); |
39 encoder.Enqueue('1'); | 36 encoder.Enqueue('1'); |
40 encoder.EnqueueAll(packed_words); | 37 encoder.EnqueueAll(packed_words); |
41 | 38 |
42 encoder.GetEncoding(packed); | 39 encoder.GetEncoding(packed); |
43 | 40 |
44 // Pad packed to a whole number of words. This padding will decode as | 41 // Pad packed to a whole number of words. This padding will decode as |
45 // LEB128 zeroes. Run-length decoding ignores it because encoding | 42 // LEB128 zeroes. Run-length decoding ignores it because encoding |
46 // embeds the pairs count in the stream itself. | 43 // embeds the pairs count in the stream itself. |
47 while (packed->size() % sizeof(uint32_t)) | 44 while (packed->size() % sizeof(ELF::Word)) |
48 packed->push_back(0); | 45 packed->push_back(0); |
49 } | 46 } |
50 | 47 |
51 // Unpack R_ARM_RELATIVE relocations from a run-length encoded packed | 48 // Unpack ARM relative relocations from a run-length encoded packed |
52 // representation. | 49 // representation. |
53 void RelocationPacker::UnpackRelativeRelocations( | 50 void RelocationPacker::UnpackRelativeRelocations( |
54 const std::vector<uint8_t>& packed, | 51 const std::vector<uint8_t>& packed, |
55 std::vector<Elf32_Rel>* relocations) { | 52 std::vector<ELF::Rel>* relocations) { |
56 | 53 |
57 // LEB128 decode, after checking and stripping "APR1" prefix. | 54 // LEB128 decode, after checking and stripping "APR1" prefix. |
58 std::vector<Elf32_Word> packed_words; | 55 std::vector<ELF::Xword> packed_words; |
59 Leb128Decoder decoder(packed); | 56 Leb128Decoder decoder(packed); |
60 CHECK(decoder.Dequeue() == 'A' && decoder.Dequeue() == 'P' && | 57 CHECK(decoder.Dequeue() == 'A' && decoder.Dequeue() == 'P' && |
61 decoder.Dequeue() == 'R' && decoder.Dequeue() == '1'); | 58 decoder.Dequeue() == 'R' && decoder.Dequeue() == '1'); |
62 decoder.DequeueAll(&packed_words); | 59 decoder.DequeueAll(&packed_words); |
63 | 60 |
64 // Run-length decode. | 61 // Run-length decode. |
65 RelocationRunLengthCodec codec; | 62 RelocationRunLengthCodec codec; |
66 codec.Decode(packed_words, relocations); | 63 codec.Decode(packed_words, relocations); |
67 } | 64 } |
68 | 65 |
69 } // namespace relocation_packer | 66 } // namespace relocation_packer |
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