1 //===-- llvm/Support/Compression.h ---Compression----------------*- 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 // This file contains basic functions for compression/decompression.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #ifndef LLVM_SUPPORT_COMPRESSION_H
14 #define LLVM_SUPPORT_COMPRESSION_H
15
16 #include "llvm/ADT/ArrayRef.h"
17 #include "llvm/Support/DataTypes.h"
18
19 namespace llvm {
20 template <typename T> class SmallVectorImpl;
21 class Error;
22
23 // None indicates no compression. The other members are a subset of
24 // compression::Format, which is used for compressed debug sections in some
25 // object file formats (e.g. ELF). This is a separate class as we may add new
26 // compression::Format members for non-debugging purposes.
27 enum class DebugCompressionType {
28 None, ///< No compression
29 Zlib, ///< zlib
30 Zstd, ///< Zstandard
31 };
32
33 namespace compression {
34 namespace zlib {
35
36 constexpr int NoCompression = 0;
37 constexpr int BestSpeedCompression = 1;
38 constexpr int DefaultCompression = 6;
39 constexpr int BestSizeCompression = 9;
40
41 bool isAvailable();
42
43 void compress(ArrayRef<uint8_t> Input,
44 SmallVectorImpl<uint8_t> &CompressedBuffer,
45 int Level = DefaultCompression);
46
47 Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
48 size_t &UncompressedSize);
49
50 Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
51 size_t UncompressedSize);
52
53 } // End of namespace zlib
54
55 namespace zstd {
56
57 constexpr int NoCompression = -5;
58 constexpr int BestSpeedCompression = 1;
59 constexpr int DefaultCompression = 5;
60 constexpr int BestSizeCompression = 12;
61
62 bool isAvailable();
63
64 void compress(ArrayRef<uint8_t> Input,
65 SmallVectorImpl<uint8_t> &CompressedBuffer,
66 int Level = DefaultCompression, bool EnableLdm = false);
67
68 Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
69 size_t &UncompressedSize);
70
71 Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
72 size_t UncompressedSize);
73
74 } // End of namespace zstd
75
76 enum class Format {
77 Zlib,
78 Zstd,
79 };
80
formatFor(DebugCompressionType Type)81 inline Format formatFor(DebugCompressionType Type) {
82 switch (Type) {
83 case DebugCompressionType::None:
84 llvm_unreachable("not a compression type");
85 case DebugCompressionType::Zlib:
86 return Format::Zlib;
87 case DebugCompressionType::Zstd:
88 return Format::Zstd;
89 }
90 llvm_unreachable("");
91 }
92
93 struct Params {
ParamsParams94 constexpr Params(Format F)
95 : format(F), level(F == Format::Zlib ? zlib::DefaultCompression
96 : zstd::DefaultCompression) {}
97 constexpr Params(Format F, int L, bool Ldm = false)
formatParams98 : format(F), level(L), zstdEnableLdm(Ldm) {}
ParamsParams99 Params(DebugCompressionType Type) : Params(formatFor(Type)) {}
100
101 Format format;
102 int level;
103 bool zstdEnableLdm = false; // Enable zstd long distance matching
104 // This may support multi-threading for zstd in the future. Note that
105 // different threads may produce different output, so be careful if certain
106 // output determinism is desired.
107 };
108
109 // Return nullptr if LLVM was built with support (LLVM_ENABLE_ZLIB,
110 // LLVM_ENABLE_ZSTD) for the specified compression format; otherwise
111 // return a string literal describing the reason.
112 const char *getReasonIfUnsupported(Format F);
113
114 // Compress Input with the specified format P.Format. If Level is -1, use
115 // *::DefaultCompression for the format.
116 void compress(Params P, ArrayRef<uint8_t> Input,
117 SmallVectorImpl<uint8_t> &Output);
118
119 // Decompress Input. The uncompressed size must be available.
120 Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
121 uint8_t *Output, size_t UncompressedSize);
122 Error decompress(Format F, ArrayRef<uint8_t> Input,
123 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);
124 Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
125 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);
126
127 } // End of namespace compression
128
129 } // End of namespace llvm
130
131 #endif
132