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// Copyright (c) 2020 André Perez Maselco
//
// 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_push_ids_through_variables.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/transformation_push_id_through_variable.h"
namespace spvtools {
namespace fuzz {
FuzzerPassPushIdsThroughVariables::FuzzerPassPushIdsThroughVariables(
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 FuzzerPassPushIdsThroughVariables::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 pushing an id through a variable.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfPushingIdThroughVariable())) {
return;
}
// The block containing the instruction we are going to insert before
// must be reachable.
if (!GetIRContext()->IsReachable(*block)) {
return;
}
// It must be valid to insert OpStore and OpLoad instructions
// before the instruction to insert before.
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(
SpvOpStore, instruction_iterator) ||
!fuzzerutil::CanInsertOpcodeBeforeInstruction(
SpvOpLoad, instruction_iterator)) {
return;
}
// Randomly decides whether a global or local variable will be added.
auto variable_storage_class = GetFuzzerContext()->ChooseEven()
? SpvStorageClassPrivate
: SpvStorageClassFunction;
// Gets the available basic and pointer types.
auto basic_type_ids_and_pointers =
GetAvailableBasicTypesAndPointers(variable_storage_class);
auto& basic_types = basic_type_ids_and_pointers.first;
// There must be at least some basic types.
if (basic_types.empty()) {
return;
}
uint32_t basic_type_id =
basic_types[GetFuzzerContext()->RandomIndex(basic_types)];
// Looks for ids that we might wish to consider pushing through a
// variable.
std::vector<opt::Instruction*> value_instructions =
FindAvailableInstructions(
function, block, instruction_iterator,
[this, basic_type_id, instruction_descriptor](
opt::IRContext* ir_context,
opt::Instruction* instruction) -> bool {
if (!instruction->result_id() || !instruction->type_id()) {
return false;
}
if (instruction->type_id() != basic_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.
if (!GetTransformationContext()
->GetFactManager()
->IdIsIrrelevant(instruction->result_id()) &&
!fuzzerutil::CanMakeSynonymOf(ir_context,
*GetTransformationContext(),
*instruction)) {
return false;
}
return fuzzerutil::IdIsAvailableBeforeInstruction(
ir_context,
FindInstruction(instruction_descriptor, ir_context),
instruction->result_id());
});
if (value_instructions.empty()) {
return;
}
// If the pointer type does not exist, then create it.
FindOrCreatePointerType(basic_type_id, variable_storage_class);
// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/3403):
// type support here is limited by the FindOrCreateZeroConstant
// function.
const auto* type_inst =
GetIRContext()->get_def_use_mgr()->GetDef(basic_type_id);
assert(type_inst);
switch (type_inst->opcode()) {
case SpvOpTypeBool:
case SpvOpTypeFloat:
case SpvOpTypeInt:
case SpvOpTypeArray:
case SpvOpTypeMatrix:
case SpvOpTypeVector:
case SpvOpTypeStruct:
break;
default:
return;
}
// Create a constant to initialize the variable from. This might update
// module's id bound so it must be done before any fresh ids are
// computed.
auto initializer_id = FindOrCreateZeroConstant(basic_type_id, false);
// Applies the push id through variable transformation.
ApplyTransformation(TransformationPushIdThroughVariable(
value_instructions[GetFuzzerContext()->RandomIndex(
value_instructions)]
->result_id(),
GetFuzzerContext()->GetFreshId(), GetFuzzerContext()->GetFreshId(),
variable_storage_class, initializer_id, instruction_descriptor));
});
}
} // namespace fuzz
} // namespace spvtools
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