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// 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_pass_adjust_memory_operands_masks.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/transformation_set_memory_operands_mask.h"
namespace spvtools {
namespace fuzz {
FuzzerPassAdjustMemoryOperandsMasks::FuzzerPassAdjustMemoryOperandsMasks(
opt::IRContext* ir_context, TransformationContext* transformation_context,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations,
bool ignore_inapplicable_transformations)
: FuzzerPass(ir_context, transformation_context, fuzzer_context,
transformations, ignore_inapplicable_transformations) {}
void FuzzerPassAdjustMemoryOperandsMasks::Apply() {
// Consider every block in every function.
for (auto& function : *GetIRContext()->module()) {
for (auto& block : function) {
// Consider every instruction in this block, using an explicit iterator so
// that when we find an instruction of interest we can search backwards to
// create an id descriptor for it.
for (auto inst_it = block.cbegin(); inst_it != block.cend(); ++inst_it) {
if (!TransformationSetMemoryOperandsMask::IsMemoryAccess(*inst_it)) {
// We are only interested in memory access instructions.
continue;
}
std::vector<uint32_t> indices_of_available_masks_to_adjust;
// All memory instructions have at least one memory operands mask.
indices_of_available_masks_to_adjust.push_back(0);
// From SPIR-V 1.4 onwards, OpCopyMemory and OpCopyMemorySized have a
// second mask.
switch (inst_it->opcode()) {
case SpvOpCopyMemory:
case SpvOpCopyMemorySized:
if (TransformationSetMemoryOperandsMask::
MultipleMemoryOperandMasksAreSupported(GetIRContext())) {
indices_of_available_masks_to_adjust.push_back(1);
}
break;
default:
break;
}
// Consider the available masks
for (auto mask_index : indices_of_available_masks_to_adjust) {
// Randomly decide whether to adjust this mask.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()
->GetChanceOfAdjustingMemoryOperandsMask())) {
continue;
}
// Get the existing mask, using None if there was no mask present at
// all.
auto existing_mask_in_operand_index =
TransformationSetMemoryOperandsMask::GetInOperandIndexForMask(
*inst_it, mask_index);
auto existing_mask =
existing_mask_in_operand_index < inst_it->NumInOperands()
? inst_it->GetSingleWordInOperand(
existing_mask_in_operand_index)
: static_cast<uint32_t>(SpvMemoryAccessMaskNone);
// There are two things we can do to a mask:
// - add Volatile if not already present
// - toggle Nontemporal
// The following ensures that we do at least one of these
bool add_volatile = !(existing_mask & SpvMemoryAccessVolatileMask) &&
GetFuzzerContext()->ChooseEven();
bool toggle_nontemporal =
!add_volatile || GetFuzzerContext()->ChooseEven();
// These bitwise operations use '|' to add Volatile if desired, and
// '^' to toggle Nontemporal if desired.
uint32_t new_mask =
(existing_mask | (add_volatile ? SpvMemoryAccessVolatileMask
: SpvMemoryAccessMaskNone)) ^
(toggle_nontemporal ? SpvMemoryAccessNontemporalMask
: SpvMemoryAccessMaskNone);
TransformationSetMemoryOperandsMask transformation(
MakeInstructionDescriptor(block, inst_it), new_mask, mask_index);
ApplyTransformation(transformation);
}
}
}
}
}
} // namespace fuzz
} // namespace spvtools
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