SPIRV-Tools/source/fuzz/fuzzer_context.cpp
Alastair Donaldson 521223b70a
spirv-fuzz: Make functions "livesafe" during donation (#3146)
This change allows the generator to (optionally and at random) make
the functions of a module "livesafe" during donation. This involves
introducing a loop limiter variable to each function and gating the
number of total loop iterations for the function using that variable.
It also involves eliminating OpKill and OpUnreachable instructions
(changing them to OpReturn/OpReturnValue), and clamping access chain
indices so that they are always in-bounds.
2020-01-29 15:52:31 +00:00

131 lines
5.9 KiB
C++

// Copyright (c) 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/fuzz/fuzzer_context.h"
#include <cmath>
namespace spvtools {
namespace fuzz {
namespace {
// Default <minimum, maximum> pairs of probabilities for applying various
// transformations. All values are percentages. Keep them in alphabetical order.
const std::pair<uint32_t, uint32_t> kChanceOfAddingDeadBlock = {20, 90};
const std::pair<uint32_t, uint32_t> kChanceOfAddingDeadBreak = {5, 80};
const std::pair<uint32_t, uint32_t> kChanceOfAddingDeadContinue = {5, 80};
const std::pair<uint32_t, uint32_t> kChanceOfAddingNoContractionDecoration = {
5, 70};
const std::pair<uint32_t, uint32_t> kChanceOfAdjustingFunctionControl = {20,
70};
const std::pair<uint32_t, uint32_t> kChanceOfAdjustingLoopControl = {20, 90};
const std::pair<uint32_t, uint32_t> kChanceOfAdjustingMemoryOperandsMask = {20,
90};
const std::pair<uint32_t, uint32_t> kChanceOfAdjustingSelectionControl = {20,
90};
const std::pair<uint32_t, uint32_t> kChanceOfConstructingComposite = {20, 50};
const std::pair<uint32_t, uint32_t> kChanceOfCopyingObject = {20, 50};
const std::pair<uint32_t, uint32_t> kChanceOfDonatingAdditionalModule = {5, 50};
const std::pair<uint32_t, uint32_t> kChanceOfMakingDonorLivesafe = {40, 60};
const std::pair<uint32_t, uint32_t> kChanceOfMergingBlocks = {20, 95};
const std::pair<uint32_t, uint32_t> kChanceOfMovingBlockDown = {20, 50};
const std::pair<uint32_t, uint32_t> kChanceOfObfuscatingConstant = {10, 90};
const std::pair<uint32_t, uint32_t> kChanceOfOutliningFunction = {10, 90};
const std::pair<uint32_t, uint32_t> kChanceOfReplacingIdWithSynonym = {10, 90};
const std::pair<uint32_t, uint32_t> kChanceOfSplittingBlock = {40, 95};
// Default limits for various quantities that are chosen during fuzzing.
// Keep them in alphabetical order.
const uint32_t kDefaultMaxLoopControlPartialCount = 100;
const uint32_t kDefaultMaxLoopControlPeelCount = 100;
const uint32_t kDefaultMaxLoopLimit = 20;
// Default functions for controlling how deep to go during recursive
// generation/transformation. Keep them in alphabetical order.
const std::function<bool(uint32_t, RandomGenerator*)>
kDefaultGoDeeperInConstantObfuscation =
[](uint32_t current_depth, RandomGenerator* random_generator) -> bool {
double chance = 1.0 / std::pow(3.0, static_cast<float>(current_depth + 1));
return random_generator->RandomDouble() < chance;
};
} // namespace
FuzzerContext::FuzzerContext(RandomGenerator* random_generator,
uint32_t min_fresh_id)
: random_generator_(random_generator),
next_fresh_id_(min_fresh_id),
go_deeper_in_constant_obfuscation_(
kDefaultGoDeeperInConstantObfuscation) {
chance_of_adding_dead_block_ =
ChooseBetweenMinAndMax(kChanceOfAddingDeadBlock);
chance_of_adding_dead_break_ =
ChooseBetweenMinAndMax(kChanceOfAddingDeadBreak);
chance_of_adding_dead_continue_ =
ChooseBetweenMinAndMax(kChanceOfAddingDeadContinue);
chance_of_adding_no_contraction_decoration_ =
ChooseBetweenMinAndMax(kChanceOfAddingNoContractionDecoration);
chance_of_adjusting_function_control_ =
ChooseBetweenMinAndMax(kChanceOfAdjustingFunctionControl);
chance_of_adjusting_loop_control_ =
ChooseBetweenMinAndMax(kChanceOfAdjustingLoopControl);
chance_of_adjusting_memory_operands_mask_ =
ChooseBetweenMinAndMax(kChanceOfAdjustingMemoryOperandsMask);
chance_of_adjusting_selection_control_ =
ChooseBetweenMinAndMax(kChanceOfAdjustingSelectionControl);
chance_of_constructing_composite_ =
ChooseBetweenMinAndMax(kChanceOfConstructingComposite);
chance_of_copying_object_ = ChooseBetweenMinAndMax(kChanceOfCopyingObject);
chance_of_donating_additional_module_ =
ChooseBetweenMinAndMax(kChanceOfDonatingAdditionalModule);
chance_of_making_donor_livesafe_ =
ChooseBetweenMinAndMax(kChanceOfMakingDonorLivesafe);
chance_of_merging_blocks_ = ChooseBetweenMinAndMax(kChanceOfMergingBlocks);
chance_of_moving_block_down_ =
ChooseBetweenMinAndMax(kChanceOfMovingBlockDown);
chance_of_obfuscating_constant_ =
ChooseBetweenMinAndMax(kChanceOfObfuscatingConstant);
chance_of_outlining_function_ =
ChooseBetweenMinAndMax(kChanceOfOutliningFunction);
chance_of_replacing_id_with_synonym_ =
ChooseBetweenMinAndMax(kChanceOfReplacingIdWithSynonym);
chance_of_splitting_block_ = ChooseBetweenMinAndMax(kChanceOfSplittingBlock);
max_loop_control_partial_count_ = kDefaultMaxLoopControlPartialCount;
max_loop_control_peel_count_ = kDefaultMaxLoopControlPeelCount;
max_loop_limit_ = kDefaultMaxLoopLimit;
}
FuzzerContext::~FuzzerContext() = default;
uint32_t FuzzerContext::GetFreshId() { return next_fresh_id_++; }
bool FuzzerContext::ChooseEven() { return random_generator_->RandomBool(); }
bool FuzzerContext::ChoosePercentage(uint32_t percentage_chance) {
assert(percentage_chance <= 100);
return random_generator_->RandomPercentage() < percentage_chance;
}
uint32_t FuzzerContext::ChooseBetweenMinAndMax(
const std::pair<uint32_t, uint32_t>& min_max) {
assert(min_max.first <= min_max.second);
return min_max.first +
random_generator_->RandomUint32(min_max.second - min_max.first + 1);
}
} // namespace fuzz
} // namespace spvtools