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_copy_objects.h"
16
17 #include "source/fuzz/fuzzer_util.h"
18 #include "source/fuzz/transformation_copy_object.h"
19
20 namespace spvtools {
21 namespace fuzz {
22
FuzzerPassCopyObjects(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations)23 FuzzerPassCopyObjects::FuzzerPassCopyObjects(
24 opt::IRContext* ir_context, TransformationContext* transformation_context,
25 FuzzerContext* fuzzer_context,
26 protobufs::TransformationSequence* transformations)
27 : FuzzerPass(ir_context, transformation_context, fuzzer_context,
28 transformations) {}
29
30 FuzzerPassCopyObjects::~FuzzerPassCopyObjects() = default;
31
Apply()32 void FuzzerPassCopyObjects::Apply() {
33 ForEachInstructionWithInstructionDescriptor(
34 [this](opt::Function* function, opt::BasicBlock* block,
35 opt::BasicBlock::iterator inst_it,
36 const protobufs::InstructionDescriptor& instruction_descriptor)
37 -> void {
38 assert(inst_it->opcode() ==
39 instruction_descriptor.target_instruction_opcode() &&
40 "The opcode of the instruction we might insert before must be "
41 "the same as the opcode in the descriptor for the instruction");
42
43 // Check whether it is legitimate to insert a copy before this
44 // instruction.
45 if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpCopyObject,
46 inst_it)) {
47 return;
48 }
49
50 // Randomly decide whether to try inserting an object copy here.
51 if (!GetFuzzerContext()->ChoosePercentage(
52 GetFuzzerContext()->GetChanceOfCopyingObject())) {
53 return;
54 }
55
56 std::vector<opt::Instruction*> relevant_instructions =
57 FindAvailableInstructions(function, block, inst_it,
58 fuzzerutil::CanMakeSynonymOf);
59
60 // At this point, |relevant_instructions| contains all the instructions
61 // we might think of copying.
62 if (relevant_instructions.empty()) {
63 return;
64 }
65
66 // Choose a copyable instruction at random, and create and apply an
67 // object copying transformation based on it.
68 ApplyTransformation(TransformationCopyObject(
69 relevant_instructions[GetFuzzerContext()->RandomIndex(
70 relevant_instructions)]
71 ->result_id(),
72 instruction_descriptor, GetFuzzerContext()->GetFreshId()));
73 });
74 }
75
76 } // namespace fuzz
77 } // namespace spvtools
78