SPIRV-Tools/source/opt/decompose_initialized_variables_pass.cpp

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// 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/decompose_initialized_variables_pass.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace opt {
using inst_iterator = InstructionList::iterator;
namespace {
bool HasInitializer(Instruction* inst) {
if (inst->opcode() != SpvOpVariable) return false;
if (inst->NumOperands() < 4) return false;
return true;
}
} // namespace
Pass::Status DecomposeInitializedVariablesPass::Process() {
auto* module = context()->module();
std::unordered_set<Instruction*> changed;
std::vector<std::tuple<uint32_t, uint32_t>> global_stores;
for (auto iter = module->types_values_begin();
iter != module->types_values_end(); ++iter) {
Instruction* inst = &(*iter);
if (!HasInitializer(inst)) continue;
auto var_id = inst->result_id();
auto val_id = inst->GetOperand(3).words[0];
global_stores.push_back(std::make_tuple(var_id, val_id));
iter->RemoveOperand(3);
changed.insert(&*iter);
}
std::unordered_set<uint32_t> entry_ids;
for (auto entry = module->entry_points().begin();
entry != module->entry_points().end(); ++entry) {
entry_ids.insert(entry->GetSingleWordInOperand(1));
}
for (auto func = module->begin(); func != module->end(); ++func) {
std::vector<Instruction*> function_stores;
auto first_block = func->entry().get();
inst_iterator insert_point = first_block->begin();
for (auto iter = first_block->begin();
iter != first_block->end() && iter->opcode() == SpvOpVariable;
++iter) {
// For valid SPIRV-V, there is guaranteed to be at least one instruction
// after the OpVariable instructions.
insert_point = (*iter).NextNode();
Instruction* inst = &(*iter);
if (!HasInitializer(inst)) continue;
auto var_id = inst->result_id();
auto val_id = inst->GetOperand(3).words[0];
Instruction* store_inst = new Instruction(
context(), SpvOpStore, 0, 0,
{{SPV_OPERAND_TYPE_ID, {var_id}}, {SPV_OPERAND_TYPE_ID, {val_id}}});
function_stores.push_back(store_inst);
iter->RemoveOperand(3);
changed.insert(&*iter);
}
if (entry_ids.find(func->result_id()) != entry_ids.end()) {
for (auto store_ids : global_stores) {
uint32_t var_id;
uint32_t val_id;
std::tie(var_id, val_id) = store_ids;
auto* store_inst = new Instruction(
context(), SpvOpStore, 0, 0,
{{SPV_OPERAND_TYPE_ID, {var_id}}, {SPV_OPERAND_TYPE_ID, {val_id}}});
context()->set_instr_block(store_inst, &*first_block);
first_block->AddInstruction(std::unique_ptr<Instruction>(store_inst));
store_inst->InsertBefore(&*insert_point);
changed.insert(store_inst);
}
}
for (auto store = function_stores.begin(); store != function_stores.end();
++store) {
context()->set_instr_block(*store, first_block);
(*store)->InsertBefore(&*insert_point);
changed.insert(*store);
}
}
auto* def_use_mgr = get_def_use_mgr();
for (auto* inst : changed) def_use_mgr->UpdateDefUse(inst);
return !changed.empty() ? Pass::Status::SuccessWithChange
: Pass::Status::SuccessWithoutChange;
}
} // namespace opt
} // namespace spvtools