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https://github.com/KhronosGroup/SPIRV-Tools
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fe10239f92
This change adds fuzzer passes that sprinkle loads and stores into a module at random, with stores restricted to occur in either dead blocks, or to use pointers for which it is known that the pointee value does not influence the module's overall behaviour. The change also generalises the VariableValueIsArbitrary fact to PointeeValueIsIrrelevant, to allow stores through access chains or object copies of variables whose values are known to be irrelevant. The change includes some other minor refactorings.
129 lines
4.4 KiB
C++
129 lines
4.4 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/transformation_store.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/instruction_descriptor.h"
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namespace spvtools {
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namespace fuzz {
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TransformationStore::TransformationStore(
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const spvtools::fuzz::protobufs::TransformationStore& message)
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: message_(message) {}
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TransformationStore::TransformationStore(
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uint32_t pointer_id, uint32_t value_id,
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const protobufs::InstructionDescriptor& instruction_to_insert_before) {
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message_.set_pointer_id(pointer_id);
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message_.set_value_id(value_id);
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*message_.mutable_instruction_to_insert_before() =
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instruction_to_insert_before;
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}
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bool TransformationStore::IsApplicable(
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opt::IRContext* context,
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const spvtools::fuzz::FactManager& fact_manager) const {
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// The pointer must exist and have a type.
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auto pointer = context->get_def_use_mgr()->GetDef(message_.pointer_id());
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if (!pointer || !pointer->type_id()) {
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return false;
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}
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// The pointer type must indeed be a pointer.
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auto pointer_type = context->get_def_use_mgr()->GetDef(pointer->type_id());
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assert(pointer_type && "Type id must be defined.");
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if (pointer_type->opcode() != SpvOpTypePointer) {
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return false;
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}
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// The pointer must not be read only.
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if (pointer_type->GetSingleWordInOperand(0) == SpvStorageClassInput) {
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return false;
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}
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// We do not want to allow storing to null or undefined pointers.
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switch (pointer->opcode()) {
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case SpvOpConstantNull:
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case SpvOpUndef:
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return false;
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default:
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break;
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}
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// Determine which instruction we should be inserting before.
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auto insert_before =
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FindInstruction(message_.instruction_to_insert_before(), context);
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// It must exist, ...
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if (!insert_before) {
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return false;
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}
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// ... and it must be legitimate to insert a store before it.
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if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpStore,
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insert_before)) {
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return false;
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}
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// The block we are inserting into needs to be dead, or else the pointee type
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// of the pointer we are storing to needs to be irrelevant (otherwise the
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// store could impact on the observable behaviour of the module).
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if (!fact_manager.BlockIsDead(
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context->get_instr_block(insert_before)->id()) &&
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!fact_manager.PointeeValueIsIrrelevant(message_.pointer_id())) {
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return false;
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}
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// The value being stored needs to exist and have a type.
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auto value = context->get_def_use_mgr()->GetDef(message_.value_id());
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if (!value || !value->type_id()) {
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return false;
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}
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// The type of the value must match the pointee type.
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if (pointer_type->GetSingleWordInOperand(1) != value->type_id()) {
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return false;
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}
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// The pointer needs to be available at the insertion point.
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if (!fuzzerutil::IdIsAvailableBeforeInstruction(context, insert_before,
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message_.pointer_id())) {
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return false;
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}
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// The value needs to be available at the insertion point.
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return fuzzerutil::IdIsAvailableBeforeInstruction(context, insert_before,
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message_.value_id());
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}
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void TransformationStore::Apply(opt::IRContext* context,
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spvtools::fuzz::FactManager* /*unused*/) const {
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FindInstruction(message_.instruction_to_insert_before(), context)
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->InsertBefore(MakeUnique<opt::Instruction>(
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context, SpvOpStore, 0, 0,
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opt::Instruction::OperandList(
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{{SPV_OPERAND_TYPE_ID, {message_.pointer_id()}},
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{SPV_OPERAND_TYPE_ID, {message_.value_id()}}})));
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context->InvalidateAnalysesExceptFor(opt::IRContext::kAnalysisNone);
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}
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protobufs::Transformation TransformationStore::ToMessage() const {
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protobufs::Transformation result;
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*result.mutable_store() = message_;
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return result;
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}
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} // namespace fuzz
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} // namespace spvtools
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