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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_load.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
namespace spvtools {
namespace fuzz {
TransformationLoad::TransformationLoad(protobufs::TransformationLoad message)
: message_(std::move(message)) {}
TransformationLoad::TransformationLoad(
uint32_t fresh_id, uint32_t pointer_id,
const protobufs::InstructionDescriptor& instruction_to_insert_before) {
message_.set_fresh_id(fresh_id);
message_.set_pointer_id(pointer_id);
*message_.mutable_instruction_to_insert_before() =
instruction_to_insert_before;
}
bool TransformationLoad::IsApplicable(
opt::IRContext* ir_context, const TransformationContext& /*unused*/) const {
// The result id must be fresh.
if (!fuzzerutil::IsFreshId(ir_context, message_.fresh_id())) {
return false;
}
// The pointer must exist and have a type.
auto pointer = ir_context->get_def_use_mgr()->GetDef(message_.pointer_id());
if (!pointer || !pointer->type_id()) {
return false;
}
// The type must indeed be a pointer type.
auto pointer_type = ir_context->get_def_use_mgr()->GetDef(pointer->type_id());
assert(pointer_type && "Type id must be defined.");
if (pointer_type->opcode() != SpvOpTypePointer) {
return false;
}
// We do not want to allow loading from null or undefined pointers, as it is
// not clear how punishing the consequences of doing so are from a semantics
// point of view.
switch (pointer->opcode()) {
case SpvOpConstantNull:
case SpvOpUndef:
return false;
default:
break;
}
// Determine which instruction we should be inserting before.
auto insert_before =
FindInstruction(message_.instruction_to_insert_before(), ir_context);
// It must exist, ...
if (!insert_before) {
return false;
}
// ... and it must be legitimate to insert a store before it.
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpLoad, insert_before)) {
return false;
}
// The pointer needs to be available at the insertion point.
return fuzzerutil::IdIsAvailableBeforeInstruction(ir_context, insert_before,
message_.pointer_id());
}
void TransformationLoad::Apply(opt::IRContext* ir_context,
TransformationContext* /*unused*/) const {
uint32_t result_type = fuzzerutil::GetPointeeTypeIdFromPointerType(
ir_context, fuzzerutil::GetTypeId(ir_context, message_.pointer_id()));
fuzzerutil::UpdateModuleIdBound(ir_context, message_.fresh_id());
auto insert_before =
FindInstruction(message_.instruction_to_insert_before(), ir_context);
auto new_instruction = MakeUnique<opt::Instruction>(
ir_context, SpvOpLoad, result_type, message_.fresh_id(),
opt::Instruction::OperandList(
{{SPV_OPERAND_TYPE_ID, {message_.pointer_id()}}}));
auto new_instruction_ptr = new_instruction.get();
insert_before->InsertBefore(std::move(new_instruction));
// Inform the def-use manager about the new instruction and record its basic
// block.
ir_context->get_def_use_mgr()->AnalyzeInstDefUse(new_instruction_ptr);
ir_context->set_instr_block(new_instruction_ptr,
ir_context->get_instr_block(insert_before));
}
protobufs::Transformation TransformationLoad::ToMessage() const {
protobufs::Transformation result;
*result.mutable_load() = message_;
return result;
}
std::unordered_set<uint32_t> TransformationLoad::GetFreshIds() const {
return {message_.fresh_id()};
}
} // namespace fuzz
} // namespace spvtools
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