iree/compiler/Dialect/HAL/Target/VulkanSPIRV/VulkanSPIRVTarget.cpp

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "iree/compiler/Dialect/HAL/Target/VulkanSPIRV/VulkanSPIRVTarget.h"

#include <map>

#include "flatbuffers/flatbuffers.h"
#include "iree/compiler/Dialect/Flow/IR/FlowOps.h"
#include "iree/compiler/Dialect/HAL/Target/LegacyUtil.h"
#include "iree/compiler/Translation/SPIRV/EmbeddedKernels.h"
#include "iree/compiler/Translation/SPIRV/IREEToSPIRVPass.h"
#include "iree/schemas/spirv_executable_def_generated.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/CommandLine.h"
#include "mlir/Dialect/SPIRV/Passes.h"
#include "mlir/Dialect/SPIRV/SPIRVOps.h"
#include "mlir/Dialect/SPIRV/Serialization.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/Module.h"
#include "mlir/Pass/PassManager.h"
#include "mlir/Support/LogicalResult.h"
#include "mlir/Transforms/Passes.h"
#include "tensorflow/compiler/mlir/xla/transforms/passes.h"

namespace mlir {
namespace iree_compiler {
namespace IREE {
namespace HAL {

// TODO(benvanik): add flags.
// static llvm::cl::OptionCategory halVulkanSPIRVOptionsCategory(
//     "IREE Vulkan/SPIR-V backend options");

VulkanSPIRVTargetOptions getVulkanSPIRVTargetOptionsFromFlags() {
  VulkanSPIRVTargetOptions targetOptions;
  // TODO(benvanik): flags.
  return targetOptions;
}

// Returns a list of entry point names matching the expected export ordinals.
static std::vector<std::string> populateEntryPointNames(
    IREE::Flow::ExecutableOp executableOp) {
  std::vector<std::string> entryPointNames;
  for (auto &op : executableOp.getBlock().getOperations()) {
    if (auto entryOp = dyn_cast<IREE::Flow::DispatchEntryOp>(op)) {
      entryPointNames.push_back(entryOp.function_ref());
    } else if (auto entryOp = dyn_cast<IREE::Flow::ReductionEntryOp>(op)) {
      entryPointNames.push_back(entryOp.function_ref());
    }
  }
  return entryPointNames;
}

// Returns a pipeline layout definition based on the bindings required.
static std::unique_ptr<iree::VkPipelineLayoutDefT> populatePipelineLayout(
    spirv::ModuleOp spirvModuleOp) {
  // NOTE: we currently make some assumptions about this based on the expected
  // ABI of the runtime. If we wanted to support more general shaders with more
  // complex I/O we'd need to find a better way to communicate this through the
  // VkPipelineLayoutDef.
  auto pipelineLayoutDef = std::make_unique<iree::VkPipelineLayoutDefT>();
  pipelineLayoutDef->buffer_binding_set = 0;

  // Build a set of descriptor_set -> binding -> variable.
  // This makes it easier to write out the descriptor in a logical order, even
  // though this is not strictly required.
  int64_t maxDescriptorSetOrdinal = -1;
  std::map<int32_t, std::map<int32_t, spirv::GlobalVariableOp>> descriptorSets;
  for (auto globalVar :
       spirvModuleOp.getBlock().getOps<spirv::GlobalVariableOp>()) {
    auto descriptorSetAttr =
        globalVar.getAttrOfType<IntegerAttr>("descriptor_set");
    auto bindingAttr = globalVar.getAttrOfType<IntegerAttr>("binding");
    if (!descriptorSetAttr || !bindingAttr) {
      // Not something the runtime cares about.
      continue;
    }
    maxDescriptorSetOrdinal =
        std::max(descriptorSetAttr.getInt(), maxDescriptorSetOrdinal);
    auto &descriptorSet = descriptorSets[descriptorSetAttr.getInt()];
    descriptorSet[bindingAttr.getInt()] = globalVar;
  }

  // Create the individual layout and binding defs.
  pipelineLayoutDef->descriptor_set_layouts.resize(maxDescriptorSetOrdinal + 1);
  for (auto &descriptorSetBindings : descriptorSets) {
    int32_t descriptorSet = descriptorSetBindings.first;
    auto dsl = std::make_unique<iree::VkDescriptorSetLayoutDefT>();

    for (auto &globalVarBinding : descriptorSetBindings.second) {
      auto binding = std::make_unique<iree::VkDescriptorSetLayoutBindingDefT>();
      binding->binding = globalVarBinding.first;
      binding->descriptor_count = 1;
      // TODO(benvanik): pull from type info.
      binding->descriptor_type = 7;       // VK_DESCRIPTOR_TYPE_STORAGE_BUFFER
      binding->stage_flags = 0x00000020;  // VK_SHADER_STAGE_COMPUTE_BIT
      dsl->bindings.push_back(std::move(binding));
    }

    pipelineLayoutDef->descriptor_set_layouts[descriptorSet] = std::move(dsl);
  }

  return pipelineLayoutDef;
}

LogicalResult translateToVulkanSPIRVExecutable(
    IREE::Flow::ExecutableOp sourceOp, IREE::HAL::ExecutableOp targetOp,
    ExecutableTargetOptions executableOptions,
    VulkanSPIRVTargetOptions targetOptions) {
  // Clone the module containing the things we want to translate. We do this so
  // that multiple targets can pull from the same source without conflicting.
  auto moduleOp = sourceOp.getInnerModule().clone();
  makeLegacyExecutableABI(sourceOp, moduleOp, targetOp);

  // Try first to match against an embedded kernel (such as matmul) and
  // otherwise fall back to generating the kernel.
  iree::SpirVExecutableDefT spirvExecutableDef;
  if (tryEmbeddedKernelRewrite(moduleOp, &spirvExecutableDef)) {
    // Strip out the contents as we don't care (they were manually replaced).
    moduleOp.getBody()->getOperations().erase(
        moduleOp.getBody()->getOperations().begin(),
        --moduleOp.getBody()->getOperations().end());
  } else {
    // The sequencer and runtime use ordinals instead of names. We provide the
    // list of entry point names here that are then passed in
    // VkShaderModuleCreateInfo.
    spirvExecutableDef.entry_points = populateEntryPointNames(sourceOp);

    // Lower module to spirv::ModuleOp.
    PassManager conversionPassManager(moduleOp.getContext());
    conversionPassManager.addPass(xla_hlo::createLegalizeToStdPass());
    conversionPassManager.addPass(createPrepareReductionDispatchPass());
    conversionPassManager.addPass(createIndexComputationPass());
    conversionPassManager.addPass(createIREEToSPIRVPass());

    OpPassManager &spirvPasses = conversionPassManager.nest<spirv::ModuleOp>();
    spirvPasses.addPass(spirv::createLowerABIAttributesPass());
    spirvPasses.addPass(createInlinerPass());
    spirvPasses.addPass(createAdjustIntegerWidthPass());
    if (failed(conversionPassManager.run(moduleOp))) {
      return moduleOp.emitError() << "failed to run conversion passes";
    }
    auto spvModuleOps = moduleOp.getOps<spirv::ModuleOp>();
    if (std::distance(spvModuleOps.begin(), spvModuleOps.end()) != 1) {
      return moduleOp.emitError()
             << "Expected a single spv.module for an IREE executable op";
    }
    spirv::ModuleOp spvModuleOp = *spvModuleOps.begin();

    // Serialize the spirv::ModuleOp into the binary that we will embed in the
    // final flatbuffer.
    SmallVector<uint32_t, 256> spvBinary;
    if (failed(spirv::serialize(spvModuleOp, spvBinary))) {
      return spvModuleOp.emitError() << "failed to serialize spv.module";
    }
    spirvExecutableDef.code = {spvBinary.begin(), spvBinary.end()};
    if (spirvExecutableDef.code.empty()) {
      return spvModuleOp.emitError()
             << "failed to translate and serialize SPIR-V executable";
    }

    // Reflect against the entry thunk to identify the required pipeline
    // layout based on binding information. This is used by the runtime to
    // create the VkPipelineLayout.
    spirvExecutableDef.pipeline_layout = populatePipelineLayout(spvModuleOp);
    if (!spirvExecutableDef.pipeline_layout) {
      return spvModuleOp.emitError()
             << "failed to generate pipeline for SPIR-V module";
    }

    // Remove the original functions as we just want to keep the spv.module for
    // debugging.
    for (auto &op :
         llvm::make_early_inc_range(moduleOp.getBody()->getOperations())) {
      if (!isa<spirv::ModuleOp>(op) && !isa<ModuleTerminatorOp>(op)) {
        op.erase();
      }
    }
  }

  // Pack the executable definition and get the bytes with the proper header.
  // The header is used to verify the contents at runtime.
  ::flatbuffers::FlatBufferBuilder fbb;
  auto executableOffset =
      iree::SpirVExecutableDef::Pack(fbb, &spirvExecutableDef);
  iree::FinishSpirVExecutableDefBuffer(fbb, executableOffset);
  std::vector<uint8_t> bytes;
  bytes.resize(fbb.GetSize());
  std::memcpy(bytes.data(), fbb.GetBufferPointer(), bytes.size());

  // Add the binary data to the target executable.
  OpBuilder targetBuilder(&targetOp.getBlock());
  targetBuilder.setInsertionPoint(&targetOp.getBlock().back());
  auto binaryOp = targetBuilder.create<IREE::HAL::ExecutableBinaryOp>(
      targetOp.getLoc(),
      static_cast<uint32_t>(IREE::HAL::ExecutableFormat::SpirV),
      std::move(bytes));
  binaryOp.getBlock().getOperations().insert(
      Block::iterator(binaryOp.getBlock().back()), moduleOp);
  return success();
}

static ExecutableTargetRegistration targetRegistration(
    "vulkan-spirv",
    +[](IREE::Flow::ExecutableOp sourceOp, IREE::HAL::ExecutableOp targetOp,
        ExecutableTargetOptions executableOptions) {
      return translateToVulkanSPIRVExecutable(
          sourceOp, targetOp, executableOptions,
          getVulkanSPIRVTargetOptionsFromFlags());
    });

}  // namespace HAL
}  // namespace IREE
}  // namespace iree_compiler
}  // namespace mlir