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 #include "llvm/Config/llvm-config.h" // for LLVM_VERSION_MAJOR
  16
  17 using namespace mlir;
  18
  19 void spirv::appendModuleHeader(SmallVectorImpl<uint32_t> &header,
  20                                spirv::Version version, uint32_t idBound) {
  21   uint32_t majorVersion = 1;
  22   uint32_t minorVersion = 0;
  23   switch (version) {
  24 #define MIN_VERSION_CASE(v)                                                    \
  25   case spirv::Version::V_1_##v:                                                \
  26     minorVersion = v;                                                          \
  27     break
  28
  29     MIN_VERSION_CASE(0);
  30     MIN_VERSION_CASE(1);
  31     MIN_VERSION_CASE(2);
  32     MIN_VERSION_CASE(3);
  33     MIN_VERSION_CASE(4);
  34     MIN_VERSION_CASE(5);
  35     MIN_VERSION_CASE(6);
  36 #undef MIN_VERSION_CASE
  37   }
  38
  39   // See "2.3. Physical Layout of a SPIR-V Module and Instruction" in the SPIR-V
  40   // spec for the definition of the binary module header.
  41   //
  42   // The first five words of a SPIR-V module must be:
  43   // +-------------------------------------------------------------------------+
  44   // | Magic number                                                            |
  45   // +-------------------------------------------------------------------------+
  46   // | Version number (bytes: 0 | major number | minor number | 0)             |
  47   // +-------------------------------------------------------------------------+
  48   // | Generator magic number                                                  |
  49   // +-------------------------------------------------------------------------+
  50   // | Bound (all result <id>s in the module guaranteed to be less than it)    |
  51   // +-------------------------------------------------------------------------+
  52   // | 0 (reserved for instruction schema)                                     |
  53   // +-------------------------------------------------------------------------+
  54   header.push_back(spirv::kMagicNumber);
  55   header.push_back((majorVersion << 16) | (minorVersion << 8));
  56   header.push_back((kGeneratorNumber << 16) | LLVM_VERSION_MAJOR);
  57   header.push_back(idBound); // <id> bound
  58   header.push_back(0);       // Schema (reserved word)
  59 }
  60
  61 /// Returns the word-count-prefixed opcode for an SPIR-V instruction.
  62 uint32_t spirv::getPrefixedOpcode(uint32_t wordCount, spirv::Opcode opcode) {
  63   assert(((wordCount >> 16) == 0) && "word count out of range!");
  64   return (wordCount << 16) | static_cast<uint32_t>(opcode);
  65 }
  66
  67 void spirv::encodeStringLiteralInto(SmallVectorImpl<uint32_t> &binary,
  68                                     StringRef literal) {
  69   // We need to encode the literal and the null termination.
  70   auto encodingSize = literal.size() / 4 + 1;
  71   auto bufferStartSize = binary.size();
  72   binary.resize(bufferStartSize + encodingSize, 0);
  73   std::memcpy(binary.data() + bufferStartSize, literal.data(), literal.size());
  74 }