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// Copyright (c) 2020 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_add_composite_inserts.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/pseudo_random_generator.h"
#include "source/fuzz/transformation_composite_insert.h"
namespace spvtools {
namespace fuzz {
FuzzerPassAddCompositeInserts::FuzzerPassAddCompositeInserts(
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 FuzzerPassAddCompositeInserts::Apply() {
ForEachInstructionWithInstructionDescriptor(
[this](opt::Function* function, opt::BasicBlock* block,
opt::BasicBlock::iterator instruction_iterator,
const protobufs::InstructionDescriptor& instruction_descriptor)
-> void {
assert(instruction_iterator->opcode() ==
instruction_descriptor.target_instruction_opcode() &&
"The opcode of the instruction we might insert before must be "
"the same as the opcode in the descriptor for the instruction");
// Randomly decide whether to try adding an OpCompositeInsert
// instruction.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfAddingCompositeInsert())) {
return;
}
// It must be possible to insert an OpCompositeInsert instruction
// before |instruction_iterator|.
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(
SpvOpCompositeInsert, instruction_iterator)) {
return;
}
// Look for available values that have composite type.
std::vector<opt::Instruction*> available_composites =
FindAvailableInstructions(
function, block, instruction_iterator,
[instruction_descriptor](
opt::IRContext* ir_context,
opt::Instruction* instruction) -> bool {
// |instruction| must be a supported instruction of composite
// type.
if (!TransformationCompositeInsert::
IsCompositeInstructionSupported(ir_context,
instruction)) {
return false;
}
auto instruction_type = ir_context->get_type_mgr()->GetType(
instruction->type_id());
// No components of the composite can have type
// OpTypeRuntimeArray.
if (ContainsRuntimeArray(*instruction_type)) {
return false;
}
// No components of the composite can be pointers.
// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/3658):
// Structs can have components of pointer type.
// FindOrCreateZeroConstant cannot be called on a
// pointer. We ignore pointers for now. Consider adding
// support for pointer types.
if (ContainsPointer(*instruction_type)) {
return false;
}
return true;
});
// If there are no available values, then return.
if (available_composites.empty()) {
return;
}
// Choose randomly one available composite value.
auto available_composite =
available_composites[GetFuzzerContext()->RandomIndex(
available_composites)];
// Take a random component of the chosen composite value. If the chosen
// component is itself a composite, then randomly decide whether to take
// its component and repeat.
uint32_t current_node_type_id = available_composite->type_id();
std::vector<uint32_t> path_to_replaced;
while (true) {
auto current_node_type_inst =
GetIRContext()->get_def_use_mgr()->GetDef(current_node_type_id);
uint32_t num_of_components = fuzzerutil::GetBoundForCompositeIndex(
*current_node_type_inst, GetIRContext());
// If the composite is empty, then end the iteration.
if (num_of_components == 0) {
break;
}
uint32_t one_selected_index =
GetFuzzerContext()->GetRandomIndexForCompositeInsert(
num_of_components);
// Construct a final index by appending the current index.
path_to_replaced.push_back(one_selected_index);
current_node_type_id = fuzzerutil::WalkOneCompositeTypeIndex(
GetIRContext(), current_node_type_id, one_selected_index);
// If the component is not a composite then end the iteration.
if (!fuzzerutil::IsCompositeType(
GetIRContext()->get_type_mgr()->GetType(
current_node_type_id))) {
break;
}
// If the component is a composite, but we decide not to go deeper,
// then end the iteration.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()
->GetChanceOfGoingDeeperToInsertInComposite())) {
break;
}
}
// Look for available objects that have the type id
// |current_node_type_id| and can be inserted.
std::vector<opt::Instruction*> available_objects =
FindAvailableInstructions(
function, block, instruction_iterator,
[instruction_descriptor, current_node_type_id](
opt::IRContext* /*unused*/,
opt::Instruction* instruction) -> bool {
if (instruction->result_id() == 0 ||
instruction->type_id() == 0) {
return false;
}
if (instruction->type_id() != current_node_type_id) {
return false;
}
return true;
});
// If there are no objects of the specific type available, check if
// FindOrCreateZeroConstant can be called and create a zero constant of
// this type.
uint32_t available_object_id;
if (available_objects.empty()) {
if (!fuzzerutil::CanCreateConstant(GetIRContext(),
current_node_type_id)) {
return;
}
available_object_id =
FindOrCreateZeroConstant(current_node_type_id, false);
} else {
available_object_id =
available_objects[GetFuzzerContext()->RandomIndex(
available_objects)]
->result_id();
}
auto new_result_id = GetFuzzerContext()->GetFreshId();
// Insert an OpCompositeInsert instruction which copies
// |available_composite| and in the copy inserts the object
// of type |available_object_id| at index |index_to_replace|.
ApplyTransformation(TransformationCompositeInsert(
instruction_descriptor, new_result_id,
available_composite->result_id(), available_object_id,
path_to_replaced));
});
}
bool FuzzerPassAddCompositeInserts::ContainsPointer(
const opt::analysis::Type& type) {
switch (type.kind()) {
case opt::analysis::Type::kPointer:
return true;
case opt::analysis::Type::kArray:
return ContainsPointer(*type.AsArray()->element_type());
case opt::analysis::Type::kMatrix:
return ContainsPointer(*type.AsMatrix()->element_type());
case opt::analysis::Type::kVector:
return ContainsPointer(*type.AsVector()->element_type());
case opt::analysis::Type::kStruct:
return std::any_of(type.AsStruct()->element_types().begin(),
type.AsStruct()->element_types().end(),
[](const opt::analysis::Type* element_type) {
return ContainsPointer(*element_type);
});
default:
return false;
}
}
bool FuzzerPassAddCompositeInserts::ContainsRuntimeArray(
const opt::analysis::Type& type) {
switch (type.kind()) {
case opt::analysis::Type::kRuntimeArray:
return true;
case opt::analysis::Type::kStruct:
// If any component of a struct is of type OpTypeRuntimeArray, return
// true.
return std::any_of(type.AsStruct()->element_types().begin(),
type.AsStruct()->element_types().end(),
[](const opt::analysis::Type* element_type) {
return ContainsRuntimeArray(*element_type);
});
default:
return false;
}
}
} // namespace fuzz
} // namespace spvtools