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_mutate_pointers.h"
16
17 #include "source/fuzz/fuzzer_context.h"
18 #include "source/fuzz/fuzzer_util.h"
19 #include "source/fuzz/transformation_mutate_pointer.h"
20
21 namespace spvtools {
22 namespace fuzz {
23
FuzzerPassMutatePointers(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations)24 FuzzerPassMutatePointers::FuzzerPassMutatePointers(
25 opt::IRContext* ir_context, TransformationContext* transformation_context,
26 FuzzerContext* fuzzer_context,
27 protobufs::TransformationSequence* transformations)
28 : FuzzerPass(ir_context, transformation_context, fuzzer_context,
29 transformations) {}
30
31 FuzzerPassMutatePointers::~FuzzerPassMutatePointers() = default;
32
Apply()33 void FuzzerPassMutatePointers::Apply() {
34 ForEachInstructionWithInstructionDescriptor(
35 [this](opt::Function* function, opt::BasicBlock* block,
36 opt::BasicBlock::iterator inst_it,
37 const protobufs::InstructionDescriptor& instruction_descriptor) {
38 if (!GetFuzzerContext()->ChoosePercentage(
39 GetFuzzerContext()->GetChanceOfMutatingPointer())) {
40 return;
41 }
42
43 if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpLoad, inst_it)) {
44 return;
45 }
46
47 auto available_pointers = FindAvailableInstructions(
48 function, block, inst_it,
49 [](opt::IRContext* ir_context, opt::Instruction* inst) {
50 return TransformationMutatePointer::IsValidPointerInstruction(
51 ir_context, *inst);
52 });
53
54 if (available_pointers.empty()) {
55 return;
56 }
57
58 const auto* pointer_inst =
59 available_pointers[GetFuzzerContext()->RandomIndex(
60 available_pointers)];
61
62 // Make sure there is an irrelevant constant in the module.
63 FindOrCreateZeroConstant(fuzzerutil::GetPointeeTypeIdFromPointerType(
64 GetIRContext(), pointer_inst->type_id()),
65 true);
66
67 ApplyTransformation(TransformationMutatePointer(
68 pointer_inst->result_id(), GetFuzzerContext()->GetFreshId(),
69 instruction_descriptor));
70 });
71 }
72
73 } // namespace fuzz
74 } // namespace spvtools
75