1// smol-v - public domain - https://github.com/aras-p/smol-v
2// authored 2016-2020 by Aras Pranckevicius
3// no warranty implied; use at your own risk
4// See end of file for license information.
5//
6//
7// ### OVERVIEW:
8//
9// SMOL-V encodes Vulkan/Khronos SPIR-V format programs into a form that is smaller, and is more
10// compressible. Normally no changes to the programs are done; they decode
11// into exactly same program as what was encoded. Optionally, debug information
12// can be removed too.
13//
14// SPIR-V is a very verbose format, several times larger than same programs expressed in other
15// shader formats (e.g. DX11 bytecode, GLSL, DX9 bytecode etc.). The SSA-form with ever increasing
16// IDs is not very appreciated by regular data compressors either. SMOL-V does several things
17// to improve this:
18// - Many words, especially ones that most often have small values, are encoded using
19// "varint" scheme (1-5 bytes per word, with just one byte for values in 0..127 range).
20// See https://developers.google.com/protocol-buffers/docs/encoding
21// - Some IDs used in the program are delta-encoded, relative to previously seen IDs (e.g. Result
22// IDs). Often instructions reference things that were computed just before, so this results in
23// small deltas. These values are also encoded using "varint" scheme.
24// - Reordering instruction opcodes so that the most common ones are the smallest values, for smaller
25// varint encoding.
26// - Encoding several instructions in a more compact form, e.g. the "typical <=4 component swizzle"
27// shape of a VectorShuffle instruction, or sequences of MemberDecorate instructions.
28//
29// A somewhat similar utility is spirv-remap from glslang, see
30// https://github.com/KhronosGroup/glslang/blob/master/README-spirv-remap.txt
31//
32//
33// ### USAGE:
34//
35// Add source/smolv.h and source/smolv.cpp to your C++ project build.
36// Currently it might require C++11 or somesuch; I only tested with Visual Studio 2017/2019, Mac Xcode 11 and Gcc 5.4.
37//
38// smolv::Encode and smolv::Decode is the basic functionality.
39//
40// Other functions are for development/statistics purposes, to figure out frequencies and
41// distributions of the instructions.
42//
43// There's a test + compression benchmarking suite in testing/testmain.cpp; using that needs adding
44// other files under testing/external to the build too (3rd party code: glslang remapper, Zstd, LZ4).
45//
46//
47// ### LIMITATIONS / TODO:
48//
49// - SPIR-V where the words got stored in big-endian layout is not supported yet.
50// - The whole thing might not work on Big-Endian CPUs. It might, but I'm not 100% sure.
51// - Not much prevention is done against malformed/corrupted inputs, TODO.
52// - Out of memory cases are not handled. The code will either throw exception
53// or crash, depending on your compilation flags.
54
55#pragma once
56
57#include <stdint.h>
58#include <vector>
59#include <cstddef>
60
61namespace smolv
62{
63 typedef std::vector<uint8_t> ByteArray;
64
65 enum EncodeFlags
66 {
67 kEncodeFlagNone = 0,
68 kEncodeFlagStripDebugInfo = (1<<0), // Strip all optional SPIR-V instructions (debug names etc.)
69 };
70 enum DecodeFlags
71 {
72 kDecodeFlagNone = 0,
73 kDecodeFlagUse20160831AsZeroVersion = (1 << 0), // For "version zero" of SMOL-V encoding, use 2016 08 31 code path (this is what happens to be used by Unity 2017-2020)
74 };
75
76 // Preserve *some* OpName debug names.
77 // Return true to preserve, false to strip.
78 // This is really only used to implement a workaround for problems with some Vulkan drivers.
79 typedef bool(*StripOpNameFilterFunc)(const char* name);
80
81 // -------------------------------------------------------------------
82 // Encoding / Decoding
83
84 // Encode SPIR-V into SMOL-V.
85 //
86 // Resulting data is appended to outSmolv array (the array is not cleared).
87 //
88 // flags is bitset of EncodeFlags values.
89 //
90 // Returns false on malformed SPIR-V input; if that happens the output array might get
91 // partial/broken SMOL-V program.
92 bool Encode(const void* spirvData, size_t spirvSize, ByteArray& outSmolv, uint32_t flags = kEncodeFlagNone, StripOpNameFilterFunc stripFilter = 0);
93
94
95 // Decode SMOL-V into SPIR-V.
96 //
97 // Resulting data is written into the passed buffer. Get required buffer space with
98 // GetDecodeBufferSize; this is the size of decoded SPIR-V program.
99 //
100 // flags is bitset of DecodeFlags values.
101
102 // Decoding does no memory allocations.
103 //
104 // Returns false on malformed input; if that happens the output buffer might be only partially
105 // written to.
106 bool Decode(const void* smolvData, size_t smolvSize, void* spirvOutputBuffer, size_t spirvOutputBufferSize, uint32_t flags = kDecodeFlagNone);
107
108
109 // Given a SMOL-V program, get size of the decoded SPIR-V program.
110 // This is the buffer size that Decode expects.
111 //
112 // Returns zero on malformed input (just checks the header, not the full input).
113 size_t GetDecodedBufferSize(const void* smolvData, size_t smolvSize);
114
115
116 // -------------------------------------------------------------------
117 // Computing instruction statistics on SPIR-V/SMOL-V programs
118
119 struct Stats;
120
121 Stats* StatsCreate();
122 void StatsDelete(Stats* s);
123
124 bool StatsCalculate(Stats* stats, const void* spirvData, size_t spirvSize);
125 bool StatsCalculateSmol(Stats* stats, const void* smolvData, size_t smolvSize);
126 void StatsPrint(const Stats* stats);
127
128} // namespace smolv
129
130
131// ------------------------------------------------------------------------------
132// This software is available under 2 licenses -- choose whichever you prefer.
133// ------------------------------------------------------------------------------
134// ALTERNATIVE A - MIT License
135// Copyright (c) 2016-2020 Aras Pranckevicius
136// Permission is hereby granted, free of charge, to any person obtaining a copy of
137// this software and associated documentation files (the "Software"), to deal in
138// the Software without restriction, including without limitation the rights to
139// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
140// of the Software, and to permit persons to whom the Software is furnished to do
141// so, subject to the following conditions:
142// The above copyright notice and this permission notice shall be included in all
143// copies or substantial portions of the Software.
144// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
145// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
146// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
147// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
148// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
149// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
150// SOFTWARE.
151// ------------------------------------------------------------------------------
152// ALTERNATIVE B - Public Domain (www.unlicense.org)
153// This is free and unencumbered software released into the public domain.
154// Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
155// software, either in source code form or as a compiled binary, for any purpose,
156// commercial or non-commercial, and by any means.
157// In jurisdictions that recognize copyright laws, the author or authors of this
158// software dedicate any and all copyright interest in the software to the public
159// domain. We make this dedication for the benefit of the public at large and to
160// the detriment of our heirs and successors. We intend this dedication to be an
161// overt act of relinquishment in perpetuity of all present and future rights to
162// this software under copyright law.
163// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
164// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
165// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
166// AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
167// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
168// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
169// ------------------------------------------------------------------------------
170