SPIRV-Tools/source/opt/compact_ids_pass.cpp

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// Copyright (c) 2017 Google Inc.
//
// 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 "compact_ids_pass.h"
#include "ir_context.h"
#include <cassert>
#include <unordered_map>
namespace spvtools {
namespace opt {
using ir::Instruction;
using ir::Operand;
Pass::Status CompactIdsPass::Process(ir::IRContext* c) {
InitializeProcessing(c);
bool modified = false;
std::unordered_map<uint32_t, uint32_t> result_id_mapping;
c->module()->ForEachInst(
[&result_id_mapping, &modified](Instruction* inst) {
auto operand = inst->begin();
while (operand != inst->end()) {
const auto type = operand->type;
if (spvIsIdType(type)) {
assert(operand->words.size() == 1);
uint32_t& id = operand->words[0];
auto it = result_id_mapping.find(id);
if (it == result_id_mapping.end()) {
const uint32_t new_id =
static_cast<uint32_t>(result_id_mapping.size()) + 1;
const auto insertion_result =
result_id_mapping.emplace(id, new_id);
it = insertion_result.first;
assert(insertion_result.second);
}
if (id != it->second) {
modified = true;
id = it->second;
// Update data cached in the instruction object.
if (type == SPV_OPERAND_TYPE_RESULT_ID) {
inst->SetResultId(id);
} else if (type == SPV_OPERAND_TYPE_TYPE_ID) {
inst->SetResultType(id);
}
}
}
++operand;
}
},
true);
if (modified)
c->module()->SetIdBound(
static_cast<uint32_t>(result_id_mapping.size() + 1));
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
} // namespace opt
} // namespace spvtools