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1 // Copyright (c) 2020 Vasyl Teliman
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/fuzz/fuzzer_pass_replace_params_with_struct.h"
16 
17 #include <numeric>
18 #include <vector>
19 
20 #include "source/fuzz/fuzzer_context.h"
21 #include "source/fuzz/fuzzer_util.h"
22 #include "source/fuzz/transformation_replace_params_with_struct.h"
23 
24 namespace spvtools {
25 namespace fuzz {
26 
FuzzerPassReplaceParamsWithStruct(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations)27 FuzzerPassReplaceParamsWithStruct::FuzzerPassReplaceParamsWithStruct(
28     opt::IRContext* ir_context, TransformationContext* transformation_context,
29     FuzzerContext* fuzzer_context,
30     protobufs::TransformationSequence* transformations)
31     : FuzzerPass(ir_context, transformation_context, fuzzer_context,
32                  transformations) {}
33 
Apply()34 void FuzzerPassReplaceParamsWithStruct::Apply() {
35   for (const auto& function : *GetIRContext()->module()) {
36     auto params =
37         fuzzerutil::GetParameters(GetIRContext(), function.result_id());
38 
39     if (params.empty() || fuzzerutil::FunctionIsEntryPoint(
40                               GetIRContext(), function.result_id())) {
41       continue;
42     }
43 
44     if (!GetFuzzerContext()->ChoosePercentage(
45             GetFuzzerContext()->GetChanceOfReplacingParametersWithStruct())) {
46       continue;
47     }
48 
49     std::vector<uint32_t> parameter_index(params.size());
50     std::iota(parameter_index.begin(), parameter_index.end(), 0);
51 
52     // Remove the indices of unsupported parameters.
53     auto new_end =
54         std::remove_if(parameter_index.begin(), parameter_index.end(),
55                        [this, &params](uint32_t index) {
56                          return !TransformationReplaceParamsWithStruct::
57                              IsParameterTypeSupported(GetIRContext(),
58                                                       params[index]->type_id());
59                        });
60 
61     // std::remove_if changes the vector so that removed elements are placed at
62     // the end (i.e. [new_end, parameter_index.end()) is a range of removed
63     // elements). However, the size of the vector is not changed so we need to
64     // change that explicitly by popping those elements from the vector.
65     parameter_index.erase(new_end, parameter_index.end());
66 
67     if (parameter_index.empty()) {
68       continue;
69     }
70 
71     // Select |num_replaced_params| parameters at random. We shuffle the vector
72     // of indices for randomization and shrink it to select first
73     // |num_replaced_params| parameters.
74     auto num_replaced_params = std::min<size_t>(
75         parameter_index.size(),
76         GetFuzzerContext()->GetRandomNumberOfParametersReplacedWithStruct(
77             static_cast<uint32_t>(params.size())));
78 
79     GetFuzzerContext()->Shuffle(&parameter_index);
80     parameter_index.resize(num_replaced_params);
81 
82     // Make sure OpTypeStruct exists in the module.
83     std::vector<uint32_t> component_type_ids;
84     for (auto index : parameter_index) {
85       component_type_ids.push_back(params[index]->type_id());
86     }
87 
88     FindOrCreateStructType(component_type_ids);
89 
90     // Map parameters' indices to parameters' ids.
91     std::vector<uint32_t> parameter_id;
92     for (auto index : parameter_index) {
93       parameter_id.push_back(params[index]->result_id());
94     }
95 
96     std::map<uint32_t, uint32_t> caller_id_to_fresh_id;
97     for (const auto* inst :
98          fuzzerutil::GetCallers(GetIRContext(), function.result_id())) {
99       caller_id_to_fresh_id[inst->result_id()] =
100           GetFuzzerContext()->GetFreshId();
101     }
102 
103     ApplyTransformation(TransformationReplaceParamsWithStruct(
104         parameter_id, GetFuzzerContext()->GetFreshId(),
105         GetFuzzerContext()->GetFreshId(), caller_id_to_fresh_id));
106   }
107 }
108 
109 }  // namespace fuzz
110 }  // namespace spvtools
111