SPIRV-Tools/source/fuzz/transformation_copy_object.cpp
Alastair Donaldson fe10239f92
spirv-fuzz: Add fuzzer passes to add loads/stores (#3176)
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.
2020-02-06 16:54:34 +00:00

112 lines
4.1 KiB
C++

// 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/transformation_copy_object.h"
#include "source/fuzz/data_descriptor.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/opt/instruction.h"
#include "source/util/make_unique.h"
namespace spvtools {
namespace fuzz {
TransformationCopyObject::TransformationCopyObject(
const protobufs::TransformationCopyObject& message)
: message_(message) {}
TransformationCopyObject::TransformationCopyObject(
uint32_t object,
const protobufs::InstructionDescriptor& instruction_to_insert_before,
uint32_t fresh_id) {
message_.set_object(object);
*message_.mutable_instruction_to_insert_before() =
instruction_to_insert_before;
message_.set_fresh_id(fresh_id);
}
bool TransformationCopyObject::IsApplicable(
opt::IRContext* context, const FactManager& /*fact_manager*/) const {
if (!fuzzerutil::IsFreshId(context, message_.fresh_id())) {
// We require the id for the object copy to be unused.
return false;
}
// The id of the object to be copied must exist
auto object_inst = context->get_def_use_mgr()->GetDef(message_.object());
if (!object_inst) {
return false;
}
if (!fuzzerutil::CanMakeSynonymOf(context, object_inst)) {
return false;
}
auto insert_before =
FindInstruction(message_.instruction_to_insert_before(), context);
if (!insert_before) {
// The instruction before which the copy should be inserted was not found.
return false;
}
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpCopyObject,
insert_before)) {
return false;
}
// |message_object| must be available directly before the point where we want
// to add the copy.
return fuzzerutil::IdIsAvailableBeforeInstruction(context, insert_before,
message_.object());
}
void TransformationCopyObject::Apply(opt::IRContext* context,
FactManager* fact_manager) const {
auto object_inst = context->get_def_use_mgr()->GetDef(message_.object());
assert(object_inst && "The object to be copied must exist.");
auto insert_before_inst =
FindInstruction(message_.instruction_to_insert_before(), context);
auto destination_block = context->get_instr_block(insert_before_inst);
assert(destination_block && "The base instruction must be in a block.");
auto insert_before = fuzzerutil::GetIteratorForInstruction(
destination_block, insert_before_inst);
assert(insert_before != destination_block->end() &&
"There must be an instruction before which the copy can be inserted.");
opt::Instruction::OperandList operands = {
{SPV_OPERAND_TYPE_ID, {message_.object()}}};
insert_before->InsertBefore(MakeUnique<opt::Instruction>(
context, SpvOp::SpvOpCopyObject, object_inst->type_id(),
message_.fresh_id(), operands));
fuzzerutil::UpdateModuleIdBound(context, message_.fresh_id());
context->InvalidateAnalysesExceptFor(opt::IRContext::Analysis::kAnalysisNone);
fact_manager->AddFactDataSynonym(MakeDataDescriptor(message_.object(), {}),
MakeDataDescriptor(message_.fresh_id(), {}),
context);
if (fact_manager->PointeeValueIsIrrelevant(message_.object())) {
fact_manager->AddFactValueOfPointeeIsIrrelevant(message_.fresh_id());
}
}
protobufs::Transformation TransformationCopyObject::ToMessage() const {
protobufs::Transformation result;
*result.mutable_copy_object() = message_;
return result;
}
} // namespace fuzz
} // namespace spvtools