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_add_synonyms.h"
16
17 #include "source/fuzz/fuzzer_context.h"
18 #include "source/fuzz/fuzzer_util.h"
19 #include "source/fuzz/instruction_descriptor.h"
20 #include "source/fuzz/transformation_add_synonym.h"
21
22 namespace spvtools {
23 namespace fuzz {
24
FuzzerPassAddSynonyms(opt::IRContext * ir_context,TransformationContext * transformation_context,FuzzerContext * fuzzer_context,protobufs::TransformationSequence * transformations)25 FuzzerPassAddSynonyms::FuzzerPassAddSynonyms(
26 opt::IRContext* ir_context, TransformationContext* transformation_context,
27 FuzzerContext* fuzzer_context,
28 protobufs::TransformationSequence* transformations)
29 : FuzzerPass(ir_context, transformation_context, fuzzer_context,
30 transformations) {}
31
Apply()32 void FuzzerPassAddSynonyms::Apply() {
33 ForEachInstructionWithInstructionDescriptor(
34 [this](opt::Function* function, opt::BasicBlock* block,
35 opt::BasicBlock::iterator inst_it,
36 const protobufs::InstructionDescriptor& instruction_descriptor) {
37 if (GetTransformationContext()->GetFactManager()->BlockIsDead(
38 block->id())) {
39 // Don't create synonyms in dead blocks.
40 return;
41 }
42
43 // Skip |inst_it| if we can't insert anything above it. OpIAdd is just
44 // a representative of some instruction that might be produced by the
45 // transformation.
46 if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpIAdd, inst_it)) {
47 return;
48 }
49
50 if (!GetFuzzerContext()->ChoosePercentage(
51 GetFuzzerContext()->GetChanceOfAddingSynonyms())) {
52 return;
53 }
54
55 auto synonym_type = GetFuzzerContext()->GetRandomSynonymType();
56
57 // Select all instructions that can be used to create a synonym to.
58 auto available_instructions = FindAvailableInstructions(
59 function, block, inst_it,
60 [synonym_type, this](opt::IRContext* ir_context,
61 opt::Instruction* inst) {
62 // Check that we can create a synonym to |inst| as described by
63 // the |synonym_type| and insert it before |inst_it|.
64 return TransformationAddSynonym::IsInstructionValid(
65 ir_context, *GetTransformationContext(), inst, synonym_type);
66 });
67
68 if (available_instructions.empty()) {
69 return;
70 }
71
72 const auto* existing_synonym =
73 available_instructions[GetFuzzerContext()->RandomIndex(
74 available_instructions)];
75
76 // Make sure the module contains all instructions required to apply the
77 // transformation.
78 switch (synonym_type) {
79 case protobufs::TransformationAddSynonym::ADD_ZERO:
80 case protobufs::TransformationAddSynonym::SUB_ZERO:
81 case protobufs::TransformationAddSynonym::LOGICAL_OR:
82 // Create a zero constant to be used as an operand of the synonymous
83 // instruction.
84 FindOrCreateZeroConstant(existing_synonym->type_id(), false);
85 break;
86 case protobufs::TransformationAddSynonym::MUL_ONE:
87 case protobufs::TransformationAddSynonym::LOGICAL_AND: {
88 const auto* existing_synonym_type =
89 GetIRContext()->get_type_mgr()->GetType(
90 existing_synonym->type_id());
91 assert(existing_synonym_type && "Instruction has invalid type");
92
93 if (const auto* vector = existing_synonym_type->AsVector()) {
94 auto element_type_id =
95 GetIRContext()->get_type_mgr()->GetId(vector->element_type());
96 assert(element_type_id && "Vector's element type is invalid");
97
98 auto one_word = vector->element_type()->AsFloat()
99 ? fuzzerutil::FloatToWord(1)
100 : 1u;
101 FindOrCreateCompositeConstant(
102 std::vector<uint32_t>(
103 vector->element_count(),
104 FindOrCreateConstant({one_word}, element_type_id, false)),
105 existing_synonym->type_id(), false);
106 } else {
107 FindOrCreateConstant(
108 {existing_synonym_type->AsFloat() ? fuzzerutil::FloatToWord(1)
109 : 1u},
110 existing_synonym->type_id(), false);
111 }
112 } break;
113 default:
114 // This assertion will fail if some SynonymType is missing from the
115 // switch statement.
116 assert(
117 !TransformationAddSynonym::IsAdditionalConstantRequired(
118 synonym_type) &&
119 "|synonym_type| requires an additional constant to be present "
120 "in the module");
121 break;
122 }
123
124 ApplyTransformation(TransformationAddSynonym(
125 existing_synonym->result_id(), synonym_type,
126 GetFuzzerContext()->GetFreshId(), instruction_descriptor));
127 });
128 }
129
130 } // namespace fuzz
131 } // namespace spvtools
132