1// Copyright (c) 2017 Google Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "source/opt/compact_ids_pass.h"
16
17#include <cassert>
18#include <unordered_map>
19
20#include "source/opt/ir_context.h"
21
22namespace spvtools {
23namespace opt {
24
25Pass::Status CompactIdsPass::Process() {
26 bool modified = false;
27 std::unordered_map<uint32_t, uint32_t> result_id_mapping;
28
29 context()->module()->ForEachInst(
30 [&result_id_mapping, &modified](Instruction* inst) {
31 auto operand = inst->begin();
32 while (operand != inst->end()) {
33 const auto type = operand->type;
34 if (spvIsIdType(type)) {
35 assert(operand->words.size() == 1);
36 uint32_t& id = operand->words[0];
37 auto it = result_id_mapping.find(id);
38 if (it == result_id_mapping.end()) {
39 const uint32_t new_id =
40 static_cast<uint32_t>(result_id_mapping.size()) + 1;
41 const auto insertion_result =
42 result_id_mapping.emplace(id, new_id);
43 it = insertion_result.first;
44 assert(insertion_result.second);
45 }
46 if (id != it->second) {
47 modified = true;
48 id = it->second;
49 // Update data cached in the instruction object.
50 if (type == SPV_OPERAND_TYPE_RESULT_ID) {
51 inst->SetResultId(id);
52 } else if (type == SPV_OPERAND_TYPE_TYPE_ID) {
53 inst->SetResultType(id);
54 }
55 }
56 }
57 ++operand;
58 }
59 },
60 true);
61
62 if (modified)
63 context()->module()->SetIdBound(
64 static_cast<uint32_t>(result_id_mapping.size() + 1));
65
66 return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
67}
68
69} // namespace opt
70} // namespace spvtools
71