1 //===- SPIRVBinaryUtils.cpp - MLIR SPIR-V Binary Module Utilities ---------===//
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 defines common utilities for SPIR-V binary module.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "mlir/Target/SPIRV/SPIRVBinaryUtils.h"
14 #include "mlir/Dialect/SPIRV/IR/SPIRVTypes.h"
15 
16 using namespace mlir;
17 
18 void spirv::appendModuleHeader(SmallVectorImpl<uint32_t> &header,
19                                spirv::Version version, uint32_t idBound) {
20   uint32_t majorVersion = 1;
21   uint32_t minorVersion = 0;
22   switch (version) {
23 #define MIN_VERSION_CASE(v)                                                    \
24   case spirv::Version::V_1_##v:                                                \
25     minorVersion = v;                                                          \
26     break
27 
28     MIN_VERSION_CASE(0);
29     MIN_VERSION_CASE(1);
30     MIN_VERSION_CASE(2);
31     MIN_VERSION_CASE(3);
32     MIN_VERSION_CASE(4);
33     MIN_VERSION_CASE(5);
34 #undef MIN_VERSION_CASE
35   }
36 
37   // See "2.3. Physical Layout of a SPIR-V Module and Instruction" in the SPIR-V
38   // spec for the definition of the binary module header.
39   //
40   // The first five words of a SPIR-V module must be:
41   // +-------------------------------------------------------------------------+
42   // | Magic number                                                            |
43   // +-------------------------------------------------------------------------+
44   // | Version number (bytes: 0 | major number | minor number | 0)             |
45   // +-------------------------------------------------------------------------+
46   // | Generator magic number                                                  |
47   // +-------------------------------------------------------------------------+
48   // | Bound (all result <id>s in the module guaranteed to be less than it)    |
49   // +-------------------------------------------------------------------------+
50   // | 0 (reserved for instruction schema)                                     |
51   // +-------------------------------------------------------------------------+
52   header.push_back(spirv::kMagicNumber);
53   header.push_back((majorVersion << 16) | (minorVersion << 8));
54   header.push_back(kGeneratorNumber);
55   header.push_back(idBound); // <id> bound
56   header.push_back(0);       // Schema (reserved word)
57 }
58 
59 /// Returns the word-count-prefixed opcode for an SPIR-V instruction.
60 uint32_t spirv::getPrefixedOpcode(uint32_t wordCount, spirv::Opcode opcode) {
61   assert(((wordCount >> 16) == 0) && "word count out of range!");
62   return (wordCount << 16) | static_cast<uint32_t>(opcode);
63 }
64 
65 void spirv::encodeStringLiteralInto(SmallVectorImpl<uint32_t> &binary,
66                                     StringRef literal) {
67   // We need to encode the literal and the null termination.
68   auto encodingSize = literal.size() / 4 + 1;
69   auto bufferStartSize = binary.size();
70   binary.resize(bufferStartSize + encodingSize, 0);
71   std::memcpy(binary.data() + bufferStartSize, literal.data(), literal.size());
72 }
73