SPIRV-Tools/source/fuzz/transformation_replace_irrelevant_id.cpp

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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/transformation_replace_irrelevant_id.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/id_use_descriptor.h"
namespace spvtools {
namespace fuzz {
TransformationReplaceIrrelevantId::TransformationReplaceIrrelevantId(
protobufs::TransformationReplaceIrrelevantId message)
: message_(std::move(message)) {}
TransformationReplaceIrrelevantId::TransformationReplaceIrrelevantId(
const protobufs::IdUseDescriptor& id_use_descriptor,
uint32_t replacement_id) {
*message_.mutable_id_use_descriptor() = id_use_descriptor;
message_.set_replacement_id(replacement_id);
}
bool TransformationReplaceIrrelevantId::IsApplicable(
opt::IRContext* ir_context,
const TransformationContext& transformation_context) const {
auto id_of_interest = message_.id_use_descriptor().id_of_interest();
// The id must be irrelevant.
if (!transformation_context.GetFactManager()->IdIsIrrelevant(
id_of_interest)) {
return false;
}
// Find the instruction containing the id use, which must exist.
auto use_instruction =
FindInstructionContainingUse(message_.id_use_descriptor(), ir_context);
if (!use_instruction) {
return false;
}
// Check that the replacement id exists and retrieve its definition.
auto replacement_id_def =
ir_context->get_def_use_mgr()->GetDef(message_.replacement_id());
if (!replacement_id_def) {
return false;
}
// The type of the id of interest and of the replacement id must be the same.
uint32_t type_id_of_interest =
ir_context->get_def_use_mgr()->GetDef(id_of_interest)->type_id();
uint32_t type_replacement_id = replacement_id_def->type_id();
if (type_id_of_interest != type_replacement_id) {
return false;
}
// The replacement id must not be the result of an OpFunction instruction.
if (replacement_id_def->opcode() == SpvOpFunction) {
return false;
}
// Consistency check: an irrelevant id cannot be a pointer.
assert(
!ir_context->get_type_mgr()->GetType(type_id_of_interest)->AsPointer() &&
"An irrelevant id cannot be a pointer");
uint32_t use_in_operand_index =
message_.id_use_descriptor().in_operand_index();
// The id use must be replaceable with any other id of the same type.
if (!fuzzerutil::IdUseCanBeReplaced(ir_context, transformation_context,
use_instruction, use_in_operand_index)) {
return false;
}
if (AttemptsToReplaceVariableInitializerWithNonConstant(
*use_instruction, *replacement_id_def)) {
return false;
}
// The id must be available to use at the use point.
return fuzzerutil::IdIsAvailableAtUse(
ir_context, use_instruction,
message_.id_use_descriptor().in_operand_index(),
message_.replacement_id());
}
void TransformationReplaceIrrelevantId::Apply(
opt::IRContext* ir_context,
TransformationContext* /* transformation_context */) const {
// Find the instruction.
auto instruction_to_change =
FindInstructionContainingUse(message_.id_use_descriptor(), ir_context);
// Replace the instruction.
instruction_to_change->SetInOperand(
message_.id_use_descriptor().in_operand_index(),
{message_.replacement_id()});
ir_context->get_def_use_mgr()->EraseUseRecordsOfOperandIds(
instruction_to_change);
ir_context->get_def_use_mgr()->AnalyzeInstUse(instruction_to_change);
// No analyses need to be invalidated, since the transformation is local to a
// block, and the def-use analysis has been updated.
}
protobufs::Transformation TransformationReplaceIrrelevantId::ToMessage() const {
protobufs::Transformation result;
*result.mutable_replace_irrelevant_id() = message_;
return result;
}
std::unordered_set<uint32_t> TransformationReplaceIrrelevantId::GetFreshIds()
const {
return std::unordered_set<uint32_t>();
}
bool TransformationReplaceIrrelevantId::
AttemptsToReplaceVariableInitializerWithNonConstant(
const opt::Instruction& use_instruction,
const opt::Instruction& replacement_for_use) {
return use_instruction.opcode() == SpvOpVariable &&
!spvOpcodeIsConstant(replacement_for_use.opcode());
}
} // namespace fuzz
} // namespace spvtools