| // 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_construct_composites.h" |
| |
| #include <memory> |
| |
| #include "source/fuzz/available_instructions.h" |
| #include "source/fuzz/fuzzer_util.h" |
| #include "source/fuzz/transformation_composite_construct.h" |
| |
| namespace spvtools { |
| namespace fuzz { |
| |
| FuzzerPassConstructComposites::FuzzerPassConstructComposites( |
| opt::IRContext* ir_context, TransformationContext* transformation_context, |
| FuzzerContext* fuzzer_context, |
| protobufs::TransformationSequence* transformations) |
| : FuzzerPass(ir_context, transformation_context, fuzzer_context, |
| transformations) {} |
| |
| void FuzzerPassConstructComposites::Apply() { |
| // Gather up the ids of all composite types, but skip block-/buffer |
| // block-decorated struct types. |
| std::vector<uint32_t> composite_type_ids; |
| for (auto& inst : GetIRContext()->types_values()) { |
| if (fuzzerutil::IsCompositeType( |
| GetIRContext()->get_type_mgr()->GetType(inst.result_id())) && |
| !fuzzerutil::HasBlockOrBufferBlockDecoration(GetIRContext(), |
| inst.result_id())) { |
| composite_type_ids.push_back(inst.result_id()); |
| } |
| } |
| |
| if (composite_type_ids.empty()) { |
| // There are no composite types, so this fuzzer pass cannot do anything. |
| return; |
| } |
| |
| AvailableInstructions available_composite_constituents( |
| GetIRContext(), |
| [this](opt::IRContext* ir_context, opt::Instruction* inst) -> bool { |
| if (!inst->result_id() || !inst->type_id()) { |
| return false; |
| } |
| |
| // If the id is irrelevant, we can use it since it will not |
| // participate in DataSynonym fact. Otherwise, we should be able |
| // to produce a synonym out of the id. |
| return GetTransformationContext()->GetFactManager()->IdIsIrrelevant( |
| inst->result_id()) || |
| fuzzerutil::CanMakeSynonymOf(ir_context, |
| *GetTransformationContext(), *inst); |
| }); |
| |
| ForEachInstructionWithInstructionDescriptor( |
| [this, &available_composite_constituents, &composite_type_ids]( |
| opt::Function* /*unused*/, opt::BasicBlock* /*unused*/, |
| opt::BasicBlock::iterator inst_it, |
| const protobufs::InstructionDescriptor& instruction_descriptor) |
| -> void { |
| // Randomly decide whether to try inserting a composite construction |
| // here. |
| if (!GetFuzzerContext()->ChoosePercentage( |
| GetFuzzerContext()->GetChanceOfConstructingComposite())) { |
| return; |
| } |
| |
| // Check whether it is legitimate to insert a composite construction |
| // before the instruction. |
| if (!fuzzerutil::CanInsertOpcodeBeforeInstruction( |
| SpvOpCompositeConstruct, inst_it)) { |
| return; |
| } |
| |
| // For each instruction that is available at this program point (i.e. an |
| // instruction that is global or whose definition strictly dominates the |
| // program point) and suitable for making a synonym of, associate it |
| // with the id of its result type. |
| TypeIdToInstructions type_id_to_available_instructions; |
| auto available_instructions = |
| available_composite_constituents.GetAvailableBeforeInstruction( |
| &*inst_it); |
| for (uint32_t available_instruction_index = 0; |
| available_instruction_index < available_instructions.size(); |
| available_instruction_index++) { |
| opt::Instruction* inst = |
| available_instructions[available_instruction_index]; |
| type_id_to_available_instructions[inst->type_id()].push_back( |
| inst->result_id()); |
| } |
| |
| // At this point, |composite_type_ids| captures all the composite types |
| // we could try to create, while |type_id_to_available_instructions| |
| // captures all the available result ids we might use, organized by |
| // type. |
| |
| // Now we choose a composite type to construct, building it from |
| // available constituent components and using zero constants if suitable |
| // components are not available. |
| |
| std::vector<uint32_t> constructor_arguments; |
| uint32_t chosen_composite_type = |
| composite_type_ids[GetFuzzerContext()->RandomIndex( |
| composite_type_ids)]; |
| |
| // Construct a composite of this type, using an appropriate helper |
| // method depending on the kind of composite type. |
| auto composite_type_inst = |
| GetIRContext()->get_def_use_mgr()->GetDef(chosen_composite_type); |
| switch (composite_type_inst->opcode()) { |
| case SpvOpTypeArray: |
| constructor_arguments = FindComponentsToConstructArray( |
| *composite_type_inst, type_id_to_available_instructions); |
| break; |
| case SpvOpTypeMatrix: |
| constructor_arguments = FindComponentsToConstructMatrix( |
| *composite_type_inst, type_id_to_available_instructions); |
| break; |
| case SpvOpTypeStruct: |
| constructor_arguments = FindComponentsToConstructStruct( |
| *composite_type_inst, type_id_to_available_instructions); |
| break; |
| case SpvOpTypeVector: |
| constructor_arguments = FindComponentsToConstructVector( |
| *composite_type_inst, type_id_to_available_instructions); |
| break; |
| default: |
| assert(false && |
| "The space of possible composite types should be covered " |
| "by the above cases."); |
| break; |
| } |
| assert(!constructor_arguments.empty()); |
| |
| // Make and apply a transformation. |
| ApplyTransformation(TransformationCompositeConstruct( |
| chosen_composite_type, constructor_arguments, |
| instruction_descriptor, GetFuzzerContext()->GetFreshId())); |
| }); |
| } |
| |
| std::vector<uint32_t> |
| FuzzerPassConstructComposites::FindComponentsToConstructArray( |
| const opt::Instruction& array_type_instruction, |
| const TypeIdToInstructions& type_id_to_available_instructions) { |
| assert(array_type_instruction.opcode() == SpvOpTypeArray && |
| "Precondition: instruction must be an array type."); |
| |
| // Get the element type for the array. |
| auto element_type_id = array_type_instruction.GetSingleWordInOperand(0); |
| |
| // Get all instructions at our disposal that compute something of this element |
| // type. |
| auto available_instructions = |
| type_id_to_available_instructions.find(element_type_id); |
| |
| uint32_t array_length = |
| GetIRContext() |
| ->get_def_use_mgr() |
| ->GetDef(array_type_instruction.GetSingleWordInOperand(1)) |
| ->GetSingleWordInOperand(0); |
| |
| std::vector<uint32_t> result; |
| for (uint32_t index = 0; index < array_length; index++) { |
| if (available_instructions == type_id_to_available_instructions.cend()) { |
| // No suitable instructions are available, so use a zero constant |
| result.push_back(FindOrCreateZeroConstant(element_type_id, true)); |
| } else { |
| result.push_back( |
| available_instructions->second[GetFuzzerContext()->RandomIndex( |
| available_instructions->second)]); |
| } |
| } |
| return result; |
| } |
| |
| std::vector<uint32_t> |
| FuzzerPassConstructComposites::FindComponentsToConstructMatrix( |
| const opt::Instruction& matrix_type_instruction, |
| const TypeIdToInstructions& type_id_to_available_instructions) { |
| assert(matrix_type_instruction.opcode() == SpvOpTypeMatrix && |
| "Precondition: instruction must be a matrix type."); |
| |
| // Get the element type for the matrix. |
| auto element_type_id = matrix_type_instruction.GetSingleWordInOperand(0); |
| |
| // Get all instructions at our disposal that compute something of this element |
| // type. |
| auto available_instructions = |
| type_id_to_available_instructions.find(element_type_id); |
| |
| std::vector<uint32_t> result; |
| for (uint32_t index = 0; |
| index < matrix_type_instruction.GetSingleWordInOperand(1); index++) { |
| if (available_instructions == type_id_to_available_instructions.cend()) { |
| // No suitable components are available, so use a zero constant. |
| result.push_back(FindOrCreateZeroConstant(element_type_id, true)); |
| } else { |
| result.push_back( |
| available_instructions->second[GetFuzzerContext()->RandomIndex( |
| available_instructions->second)]); |
| } |
| } |
| return result; |
| } |
| |
| std::vector<uint32_t> |
| FuzzerPassConstructComposites::FindComponentsToConstructStruct( |
| const opt::Instruction& struct_type_instruction, |
| const TypeIdToInstructions& type_id_to_available_instructions) { |
| assert(struct_type_instruction.opcode() == SpvOpTypeStruct && |
| "Precondition: instruction must be a struct type."); |
| std::vector<uint32_t> result; |
| // Consider the type of each field of the struct. |
| for (uint32_t in_operand_index = 0; |
| in_operand_index < struct_type_instruction.NumInOperands(); |
| in_operand_index++) { |
| auto element_type_id = |
| struct_type_instruction.GetSingleWordInOperand(in_operand_index); |
| // Find the instructions at our disposal that compute something of the field |
| // type. |
| auto available_instructions = |
| type_id_to_available_instructions.find(element_type_id); |
| if (available_instructions == type_id_to_available_instructions.cend()) { |
| // No suitable component is available for this element type, so use a zero |
| // constant. |
| result.push_back(FindOrCreateZeroConstant(element_type_id, true)); |
| } else { |
| result.push_back( |
| available_instructions->second[GetFuzzerContext()->RandomIndex( |
| available_instructions->second)]); |
| } |
| } |
| return result; |
| } |
| |
| std::vector<uint32_t> |
| FuzzerPassConstructComposites::FindComponentsToConstructVector( |
| const opt::Instruction& vector_type_instruction, |
| const TypeIdToInstructions& type_id_to_available_instructions) { |
| assert(vector_type_instruction.opcode() == SpvOpTypeVector && |
| "Precondition: instruction must be a vector type."); |
| |
| // Get details of the type underlying the vector, and the width of the vector, |
| // for convenience. |
| auto element_type_id = vector_type_instruction.GetSingleWordInOperand(0); |
| auto element_type = GetIRContext()->get_type_mgr()->GetType(element_type_id); |
| auto element_count = vector_type_instruction.GetSingleWordInOperand(1); |
| |
| // Collect a mapping, from type id to width, for scalar/vector types that are |
| // smaller in width than |vector_type|, but that have the same underlying |
| // type. For example, if |vector_type| is vec4, the mapping will be: |
| // { float -> 1, vec2 -> 2, vec3 -> 3 } |
| // The mapping will have missing entries if some of these types do not exist. |
| |
| std::map<uint32_t, uint32_t> smaller_vector_type_id_to_width; |
| // Add the underlying type. This id must exist, in order for |vector_type| to |
| // exist. |
| smaller_vector_type_id_to_width[element_type_id] = 1; |
| |
| // Now add every vector type with width at least 2, and less than the width of |
| // |vector_type|. |
| for (uint32_t width = 2; width < element_count; width++) { |
| opt::analysis::Vector smaller_vector_type(element_type, width); |
| auto smaller_vector_type_id = |
| GetIRContext()->get_type_mgr()->GetId(&smaller_vector_type); |
| // We might find that there is no declared type of this smaller width. |
| // For example, a module can declare vec4 without having declared vec2 or |
| // vec3. |
| if (smaller_vector_type_id) { |
| smaller_vector_type_id_to_width[smaller_vector_type_id] = width; |
| } |
| } |
| |
| // Now we know the types that are available to us, we set about populating a |
| // vector of the right length. We do this by deciding, with no order in mind, |
| // which instructions we will use to populate the vector, and subsequently |
| // randomly choosing an order. This is to avoid biasing construction of |
| // vectors with smaller vectors to the left and scalars to the right. That is |
| // a concern because, e.g. in the case of populating a vec4, if we populate |
| // the constructor instructions left-to-right, we can always choose a vec3 to |
| // construct the first three elements, but can only choose a vec3 to construct |
| // the last three elements if we chose a float to construct the first element |
| // (otherwise there will not be space left for a vec3). |
| |
| uint32_t vector_slots_used = 0; |
| |
| // The instructions result ids we will use to construct the vector, in no |
| // particular order at this stage. |
| std::vector<uint32_t> result; |
| |
| while (vector_slots_used < element_count) { |
| std::vector<uint32_t> instructions_to_choose_from; |
| for (auto& entry : smaller_vector_type_id_to_width) { |
| if (entry.second > |
| std::min(element_count - 1, element_count - vector_slots_used)) { |
| continue; |
| } |
| auto available_instructions = |
| type_id_to_available_instructions.find(entry.first); |
| if (available_instructions == type_id_to_available_instructions.cend()) { |
| continue; |
| } |
| instructions_to_choose_from.insert(instructions_to_choose_from.end(), |
| available_instructions->second.begin(), |
| available_instructions->second.end()); |
| } |
| // If there are no instructions to choose from then use a zero constant, |
| // otherwise select one of the instructions at random. |
| uint32_t id_of_instruction_to_use = |
| instructions_to_choose_from.empty() |
| ? FindOrCreateZeroConstant(element_type_id, true) |
| : instructions_to_choose_from[GetFuzzerContext()->RandomIndex( |
| instructions_to_choose_from)]; |
| opt::Instruction* instruction_to_use = |
| GetIRContext()->get_def_use_mgr()->GetDef(id_of_instruction_to_use); |
| result.push_back(instruction_to_use->result_id()); |
| auto chosen_type = |
| GetIRContext()->get_type_mgr()->GetType(instruction_to_use->type_id()); |
| if (chosen_type->AsVector()) { |
| assert(chosen_type->AsVector()->element_type() == element_type); |
| assert(chosen_type->AsVector()->element_count() < element_count); |
| assert(chosen_type->AsVector()->element_count() <= |
| element_count - vector_slots_used); |
| vector_slots_used += chosen_type->AsVector()->element_count(); |
| } else { |
| assert(chosen_type == element_type); |
| vector_slots_used += 1; |
| } |
| } |
| assert(vector_slots_used == element_count); |
| |
| GetFuzzerContext()->Shuffle(&result); |
| return result; |
| } |
| |
| } // namespace fuzz |
| } // namespace spvtools |
