SPIRV-Tools/source/opt/generate_webgpu_initializers_pass.cpp
2019-09-11 17:18:05 -04:00

117 lines
3.7 KiB
C++

// Copyright (c) 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
//
// http://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 "source/opt/generate_webgpu_initializers_pass.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace opt {
using inst_iterator = InstructionList::iterator;
namespace {
bool NeedsWebGPUInitializer(Instruction* inst) {
if (inst->opcode() != SpvOpVariable) return false;
auto storage_class = inst->GetSingleWordOperand(2);
if (storage_class != SpvStorageClassOutput &&
storage_class != SpvStorageClassPrivate &&
storage_class != SpvStorageClassFunction) {
return false;
}
if (inst->NumOperands() > 3) return false;
return true;
}
} // namespace
Pass::Status GenerateWebGPUInitializersPass::Process() {
auto* module = context()->module();
bool changed = false;
// Handle global/module scoped variables
for (auto iter = module->types_values_begin();
iter != module->types_values_end(); ++iter) {
Instruction* inst = &(*iter);
if (inst->opcode() == SpvOpConstantNull) {
null_constant_type_map_[inst->type_id()] = inst;
seen_null_constants_.insert(inst);
continue;
}
if (!NeedsWebGPUInitializer(inst)) continue;
changed = true;
auto* constant_inst = GetNullConstantForVariable(inst);
if (!constant_inst) return Status::Failure;
if (seen_null_constants_.find(constant_inst) ==
seen_null_constants_.end()) {
constant_inst->InsertBefore(inst);
null_constant_type_map_[inst->type_id()] = inst;
seen_null_constants_.insert(inst);
}
AddNullInitializerToVariable(constant_inst, inst);
}
// Handle local/function scoped variables
for (auto func = module->begin(); func != module->end(); ++func) {
auto block = func->entry().get();
for (auto iter = block->begin();
iter != block->end() && iter->opcode() == SpvOpVariable; ++iter) {
Instruction* inst = &(*iter);
if (!NeedsWebGPUInitializer(inst)) continue;
changed = true;
auto* constant_inst = GetNullConstantForVariable(inst);
if (!constant_inst) return Status::Failure;
AddNullInitializerToVariable(constant_inst, inst);
}
}
return changed ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
Instruction* GenerateWebGPUInitializersPass::GetNullConstantForVariable(
Instruction* variable_inst) {
auto constant_mgr = context()->get_constant_mgr();
auto* def_use_mgr = get_def_use_mgr();
auto* ptr_inst = def_use_mgr->GetDef(variable_inst->type_id());
auto type_id = ptr_inst->GetInOperand(1).words[0];
if (null_constant_type_map_.find(type_id) == null_constant_type_map_.end()) {
auto* constant_type = context()->get_type_mgr()->GetType(type_id);
auto* constant = constant_mgr->GetConstant(constant_type, {});
return constant_mgr->GetDefiningInstruction(constant, type_id);
} else {
return null_constant_type_map_[type_id];
}
}
void GenerateWebGPUInitializersPass::AddNullInitializerToVariable(
Instruction* constant_inst, Instruction* variable_inst) {
auto constant_id = constant_inst->result_id();
variable_inst->AddOperand(Operand(SPV_OPERAND_TYPE_ID, {constant_id}));
get_def_use_mgr()->AnalyzeInstUse(variable_inst);
}
} // namespace opt
} // namespace spvtools