1 // Copyright (c) 2021 Shiyu Liu
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_wrap_vector_synonym.h"
16 #include "source/fuzz/fuzzer_context.h"
17 #include "source/fuzz/fuzzer_util.h"
18 #include "source/fuzz/transformation_composite_construct.h"
19 #include "source/fuzz/transformation_wrap_vector_synonym.h"
20
21 namespace spvtools {
22 namespace fuzz {
23
FuzzerPassWrapVectorSynonym(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations,bool ignore_inapplicable_transformations)24 FuzzerPassWrapVectorSynonym::FuzzerPassWrapVectorSynonym(
25 opt::IRContext* ir_context, TransformationContext* transformation_context,
26 FuzzerContext* fuzzer_context,
27 protobufs::TransformationSequence* transformations,
28 bool ignore_inapplicable_transformations)
29 : FuzzerPass(ir_context, transformation_context, fuzzer_context,
30 transformations, ignore_inapplicable_transformations) {}
31
Apply()32 void FuzzerPassWrapVectorSynonym::Apply() {
33 ForEachInstructionWithInstructionDescriptor(
34 [this](opt::Function* /*unused*/, opt::BasicBlock* /*unused*/,
35 opt::BasicBlock::iterator instruction_iterator,
36 const protobufs::InstructionDescriptor& instruction_descriptor)
37 -> void {
38
39 // Randomly decide whether to wrap it to a vector operation.
40 if (!GetFuzzerContext()->ChoosePercentage(
41 GetFuzzerContext()->GetChanceOfWrappingVectorSynonym())) {
42 return;
43 }
44
45 // The transformation is not applicable if the instruction has missing
46 // result id, type id, or is not supported type.
47 if (!TransformationWrapVectorSynonym::IsInstructionSupported(
48 GetIRContext(), *instruction_iterator)) {
49 return;
50 }
51
52 // It must be valid to insert an OpCompositeConstruct instruction
53 // before |instruction_iterator|.
54 if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(
55 SpvOpCompositeConstruct, instruction_iterator)) {
56 return;
57 }
58
59 // Get the scalar operands from the original instruction.
60 opt::Instruction* operand1 = GetIRContext()->get_def_use_mgr()->GetDef(
61 instruction_iterator->GetSingleWordInOperand(0));
62 opt::Instruction* operand2 = GetIRContext()->get_def_use_mgr()->GetDef(
63 instruction_iterator->GetSingleWordInOperand(1));
64
65 // We need to be able to make a synonym of the scalar operation's result
66 // id, as well as the operand ids (for example, they cannot be
67 // irrelevant).
68 if (!fuzzerutil::CanMakeSynonymOf(GetIRContext(),
69 *GetTransformationContext(),
70 *instruction_iterator)) {
71 return;
72 }
73 if (!fuzzerutil::CanMakeSynonymOf(
74 GetIRContext(), *GetTransformationContext(), *operand1)) {
75 return;
76 }
77 if (!fuzzerutil::CanMakeSynonymOf(
78 GetIRContext(), *GetTransformationContext(), *operand2)) {
79 return;
80 }
81
82 // Get a random vector size from 2 to 4.
83 uint32_t vector_size = GetFuzzerContext()->GetWidthOfWrappingVector();
84
85 // Randomly choose a position that target ids should be placed at.
86 // The position is in range [0, n - 1], where n is the size of the
87 // vector.
88 uint32_t position =
89 GetFuzzerContext()->GetRandomIndexForWrappingVector(vector_size);
90
91 // Stores the ids of scalar constants.
92 std::vector<uint32_t> vec1_components;
93 std::vector<uint32_t> vec2_components;
94
95 // Populate components based on vector type and size.
96 for (uint32_t i = 0; i < vector_size; ++i) {
97 if (i == position) {
98 vec1_components.emplace_back(operand1->result_id());
99 vec2_components.emplace_back(operand2->result_id());
100 } else {
101 vec1_components.emplace_back(
102 FindOrCreateZeroConstant(operand1->type_id(), true));
103 vec2_components.emplace_back(
104 FindOrCreateZeroConstant(operand2->type_id(), true));
105 }
106 }
107
108 // Add two OpCompositeConstruct to the module with result id returned.
109 // The added vectors may have different types, for instance if the
110 // scalar instruction operates on integers with differing sign.
111
112 // Add the first OpCompositeConstruct that wraps the id of the first
113 // operand.
114 uint32_t result_id1 = GetFuzzerContext()->GetFreshId();
115 ApplyTransformation(TransformationCompositeConstruct(
116 FindOrCreateVectorType(operand1->type_id(), vector_size),
117 vec1_components, instruction_descriptor, result_id1));
118
119 // Add the second OpCompositeConstruct that wraps the id of the second
120 // operand.
121 uint32_t result_id2 = GetFuzzerContext()->GetFreshId();
122 ApplyTransformation(TransformationCompositeConstruct(
123 FindOrCreateVectorType(operand2->type_id(), vector_size),
124 vec2_components, instruction_descriptor, result_id2));
125
126 // The result of the vector instruction that
127 // TransformationWrapVectorSynonym will create should be a vector of the
128 // right size, with the scalar instruction's result type as its element
129 // type. This can be distinct from the types of the operands, if the
130 // scalar instruction adds two signed integers and stores the result in
131 // an unsigned id, for example. A transformation is applied to add the
132 // right type to the module.
133 FindOrCreateVectorType(instruction_iterator->type_id(), vector_size);
134
135 // Apply transformation to do vector operation and add synonym between
136 // the result vector id and the id of the original instruction.
137 ApplyTransformation(TransformationWrapVectorSynonym(
138 instruction_iterator->result_id(), result_id1, result_id2,
139 GetFuzzerContext()->GetFreshId(), position));
140 });
141 }
142
143 } // namespace fuzz
144 } // namespace spvtools
145