mlir/lib/Target/SPIRV/SPIRVBinaryUtils.cpp

   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     MIN_VERSION_CASE(6);
  35 #undef MIN_VERSION_CASE
  36   }
  37
  38   // See "2.3. Physical Layout of a SPIR-V Module and Instruction" in the SPIR-V
  39   // spec for the definition of the binary module header.
  40   //
  41   // The first five words of a SPIR-V module must be:
  42   // +-------------------------------------------------------------------------+
  43   // | Magic number                                                            |
  44   // +-------------------------------------------------------------------------+
  45   // | Version number (bytes: 0 | major number | minor number | 0)             |
  46   // +-------------------------------------------------------------------------+
  47   // | Generator magic number                                                  |
  48   // +-------------------------------------------------------------------------+
  49   // | Bound (all result <id>s in the module guaranteed to be less than it)    |
  50   // +-------------------------------------------------------------------------+
  51   // | 0 (reserved for instruction schema)                                     |
  52   // +-------------------------------------------------------------------------+
  53   header.push_back(spirv::kMagicNumber);
  54   header.push_back((majorVersion << 16) | (minorVersion << 8));
  55   header.push_back(kGeneratorNumber);
  56   header.push_back(idBound); // <id> bound
  57   header.push_back(0);       // Schema (reserved word)
  58 }
  59
  60 /// Returns the word-count-prefixed opcode for an SPIR-V instruction.
  61 uint32_t spirv::getPrefixedOpcode(uint32_t wordCount, spirv::Opcode opcode) {
  62   assert(((wordCount >> 16) == 0) && "word count out of range!");
  63   return (wordCount << 16) | static_cast<uint32_t>(opcode);
  64 }
  65
  66 void spirv::encodeStringLiteralInto(SmallVectorImpl<uint32_t> &binary,
  67                                     StringRef literal) {
  68   // We need to encode the literal and the null termination.
  69   auto encodingSize = literal.size() / 4 + 1;
  70   auto bufferStartSize = binary.size();
  71   binary.resize(bufferStartSize + encodingSize, 0);
  72   std::memcpy(binary.data() + bufferStartSize, literal.data(), literal.size());
  73 }