1 // Copyright (c) 2019 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/fuzz/fuzzer_pass_adjust_selection_controls.h"
16
17 #include "source/fuzz/transformation_set_selection_control.h"
18
19 namespace spvtools {
20 namespace fuzz {
21
FuzzerPassAdjustSelectionControls(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations)22 FuzzerPassAdjustSelectionControls::FuzzerPassAdjustSelectionControls(
23 opt::IRContext* ir_context, TransformationContext* transformation_context,
24 FuzzerContext* fuzzer_context,
25 protobufs::TransformationSequence* transformations)
26 : FuzzerPass(ir_context, transformation_context, fuzzer_context,
27 transformations) {}
28
Apply()29 void FuzzerPassAdjustSelectionControls::Apply() {
30 // Consider every merge instruction in the module (via looking through all
31 // functions and blocks).
32 for (auto& function : *GetIRContext()->module()) {
33 for (auto& block : function) {
34 if (auto merge_inst = block.GetMergeInst()) {
35 // Ignore the instruction if it is not a selection merge.
36 if (merge_inst->opcode() != SpvOpSelectionMerge) {
37 continue;
38 }
39
40 // Choose randomly whether to change the selection control for this
41 // instruction.
42 if (!GetFuzzerContext()->ChoosePercentage(
43 GetFuzzerContext()->GetChanceOfAdjustingSelectionControl())) {
44 continue;
45 }
46
47 // The choices to change the selection control to are the set of valid
48 // controls, minus the current control.
49 std::vector<uint32_t> choices;
50 for (auto control :
51 {SpvSelectionControlMaskNone, SpvSelectionControlFlattenMask,
52 SpvSelectionControlDontFlattenMask}) {
53 if (control == merge_inst->GetSingleWordOperand(1)) {
54 continue;
55 }
56 choices.push_back(control);
57 }
58
59 // Apply the transformation and add it to the output transformation
60 // sequence.
61 TransformationSetSelectionControl transformation(
62 block.id(), choices[GetFuzzerContext()->RandomIndex(choices)]);
63 ApplyTransformation(transformation);
64 }
65 }
66 }
67 }
68
69 } // namespace fuzz
70 } // namespace spvtools
71