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https://github.com/KhronosGroup/SPIRV-Tools
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9c4481419e
spirv-fuzz features transformations that should be applicable by construction. Assertions are used to detect when such transformations turn out to be inapplicable. Failures of such assertions indicate bugs in the fuzzer. However, when using the fuzzer at scale (e.g. in ClusterFuzz) reports of these assertion failures create noise, and cause the fuzzer to exit early. This change adds an option whereby inapplicable transformations can be ignored. This reduces noise and allows fuzzing to continue even when a transformation that should be applicable but is not has been erroneously created.
84 lines
3.5 KiB
C++
84 lines
3.5 KiB
C++
// Copyright (c) 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/fuzz/fuzzer_pass_add_local_variables.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/transformation_add_local_variable.h"
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#include "source/fuzz/transformation_add_type_pointer.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassAddLocalVariables::FuzzerPassAddLocalVariables(
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opt::IRContext* ir_context, TransformationContext* transformation_context,
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FuzzerContext* fuzzer_context,
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protobufs::TransformationSequence* transformations,
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bool ignore_inapplicable_transformations)
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: FuzzerPass(ir_context, transformation_context, fuzzer_context,
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transformations, ignore_inapplicable_transformations) {}
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void FuzzerPassAddLocalVariables::Apply() {
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auto basic_type_ids_and_pointers =
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GetAvailableBasicTypesAndPointers(SpvStorageClassFunction);
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// These are the basic types that are available to this fuzzer pass.
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auto& basic_types = basic_type_ids_and_pointers.first;
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if (basic_types.empty()) {
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// The pass cannot do anything if there are no basic types.
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return;
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}
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// These are the pointers to those basic types that are *initially* available
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// to the fuzzer pass. The fuzzer pass might add pointer types in cases where
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// none are available for a given basic type.
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auto& basic_type_to_pointers = basic_type_ids_and_pointers.second;
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// Consider every function in the module.
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for (auto& function : *GetIRContext()->module()) {
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// Probabilistically keep adding random variables to this function.
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while (GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAddingLocalVariable())) {
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// Choose a random basic type; the new variable's type will be a pointer
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// to this basic type.
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uint32_t basic_type =
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basic_types[GetFuzzerContext()->RandomIndex(basic_types)];
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uint32_t pointer_type;
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std::vector<uint32_t>& available_pointers_to_basic_type =
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basic_type_to_pointers.at(basic_type);
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// Determine whether there is at least one pointer to this basic type.
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if (available_pointers_to_basic_type.empty()) {
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// There is not. Make one, to use here, and add it to the available
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// pointers for the basic type so that future variables can potentially
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// use it.
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pointer_type = GetFuzzerContext()->GetFreshId();
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ApplyTransformation(TransformationAddTypePointer(
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pointer_type, SpvStorageClassFunction, basic_type));
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available_pointers_to_basic_type.push_back(pointer_type);
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} else {
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// There is - grab one.
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pointer_type =
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available_pointers_to_basic_type[GetFuzzerContext()->RandomIndex(
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available_pointers_to_basic_type)];
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}
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ApplyTransformation(TransformationAddLocalVariable(
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GetFuzzerContext()->GetFreshId(), pointer_type, function.result_id(),
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FindOrCreateZeroConstant(basic_type, false), true));
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}
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}
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}
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} // namespace fuzz
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} // namespace spvtools
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