1 // Copyright (c) 2018 Google LLC
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/reduce/reduction_pass.h"
16
17 #include <algorithm>
18
19 #include "source/opt/build_module.h"
20
21 namespace spvtools {
22 namespace reduce {
23
TryApplyReduction(const std::vector<uint32_t> & binary,uint32_t target_function)24 std::vector<uint32_t> ReductionPass::TryApplyReduction(
25 const std::vector<uint32_t>& binary, uint32_t target_function) {
26 // We represent modules as binaries because (a) attempts at reduction need to
27 // end up in binary form to be passed on to SPIR-V-consuming tools, and (b)
28 // when we apply a reduction step we need to do it on a fresh version of the
29 // module as if the reduction step proves to be uninteresting we need to
30 // backtrack; re-parsing from binary provides a very clean way of cloning the
31 // module.
32 std::unique_ptr<opt::IRContext> context =
33 BuildModule(target_env_, consumer_, binary.data(), binary.size());
34 assert(context);
35
36 std::vector<std::unique_ptr<ReductionOpportunity>> opportunities =
37 finder_->GetAvailableOpportunities(context.get(), target_function);
38
39 // There is no point in having a granularity larger than the number of
40 // opportunities, so reduce the granularity in this case.
41 if (granularity_ > opportunities.size()) {
42 granularity_ = std::max((uint32_t)1, (uint32_t)opportunities.size());
43 }
44
45 assert(granularity_ > 0);
46
47 if (index_ >= opportunities.size()) {
48 // We have reached the end of the available opportunities and, therefore,
49 // the end of the round for this pass, so reset the index and decrease the
50 // granularity for the next round. Return an empty vector to signal the end
51 // of the round.
52 index_ = 0;
53 granularity_ = std::max((uint32_t)1, granularity_ / 2);
54 return std::vector<uint32_t>();
55 }
56
57 for (uint32_t i = index_;
58 i < std::min(index_ + granularity_, (uint32_t)opportunities.size());
59 ++i) {
60 opportunities[i]->TryToApply();
61 }
62
63 std::vector<uint32_t> result;
64 context->module()->ToBinary(&result, false);
65 return result;
66 }
67
SetMessageConsumer(MessageConsumer consumer)68 void ReductionPass::SetMessageConsumer(MessageConsumer consumer) {
69 consumer_ = std::move(consumer);
70 }
71
ReachedMinimumGranularity() const72 bool ReductionPass::ReachedMinimumGranularity() const {
73 assert(granularity_ != 0);
74 return granularity_ == 1;
75 }
76
GetName() const77 std::string ReductionPass::GetName() const { return finder_->GetName(); }
78
NotifyInteresting(bool interesting)79 void ReductionPass::NotifyInteresting(bool interesting) {
80 if (!interesting) {
81 index_ += granularity_;
82 }
83 }
84
85 } // namespace reduce
86 } // namespace spvtools
87