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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, bool is_atomic,
uint32_t memory_scope, uint32_t memory_semantics,
const protobufs::InstructionDescriptor& instruction_to_insert_before) {
message_.set_fresh_id(fresh_id);
message_.set_pointer_id(pointer_id);
message_.set_is_atomic(is_atomic);
message_.set_memory_scope_id(memory_scope);
message_.set_memory_semantics_id(memory_semantics);
*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() != spv::Op::OpTypePointer) {
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 spv::Op::OpConstantNull:
case spv::Op::OpUndef:
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 load before it.
if (!message_.is_atomic() && !fuzzerutil::CanInsertOpcodeBeforeInstruction(
spv::Op::OpLoad, insert_before)) {
return false;
}
if (message_.is_atomic() && !fuzzerutil::CanInsertOpcodeBeforeInstruction(
spv::Op::OpAtomicLoad, insert_before)) {
return false;
}
if (message_.is_atomic()) {
// Check the exists of memory scope and memory semantics ids.
auto memory_scope_instruction =
ir_context->get_def_use_mgr()->GetDef(message_.memory_scope_id());
auto memory_semantics_instruction =
ir_context->get_def_use_mgr()->GetDef(message_.memory_semantics_id());
if (!memory_scope_instruction) {
return false;
}
if (!memory_semantics_instruction) {
return false;
}
// The memory scope and memory semantics instructions must have the
// 'OpConstant' opcode.
if (memory_scope_instruction->opcode() != spv::Op::OpConstant) {
return false;
}
if (memory_semantics_instruction->opcode() != spv::Op::OpConstant) {
return false;
}
// The memory scope and memory semantics need to be available before
// |insert_before|.
if (!fuzzerutil::IdIsAvailableBeforeInstruction(
ir_context, insert_before, message_.memory_scope_id())) {
return false;
}
if (!fuzzerutil::IdIsAvailableBeforeInstruction(
ir_context, insert_before, message_.memory_semantics_id())) {
return false;
}
// The memory scope and memory semantics instructions must have an Integer
// operand type with signedness does not matters.
if (ir_context->get_def_use_mgr()
->GetDef(memory_scope_instruction->type_id())
->opcode() != spv::Op::OpTypeInt) {
return false;
}
if (ir_context->get_def_use_mgr()
->GetDef(memory_semantics_instruction->type_id())
->opcode() != spv::Op::OpTypeInt) {
return false;
}
// The size of the integer for memory scope and memory semantics
// instructions must be equal to 32 bits.
auto memory_scope_int_width =
ir_context->get_def_use_mgr()
->GetDef(memory_scope_instruction->type_id())
->GetSingleWordInOperand(0);
auto memory_semantics_int_width =
ir_context->get_def_use_mgr()
->GetDef(memory_semantics_instruction->type_id())
->GetSingleWordInOperand(0);
if (memory_scope_int_width != 32) {
return false;
}
if (memory_semantics_int_width != 32) {
return false;
}
// The memory scope constant value must be that of spv::Scope::Invocation.
auto memory_scope_const_value =
spv::Scope(memory_scope_instruction->GetSingleWordInOperand(0));
if (memory_scope_const_value != spv::Scope::Invocation) {
return false;
}
// The memory semantics constant value must match the storage class of the
// pointer being loaded from.
auto memory_semantics_const_value = static_cast<spv::MemorySemanticsMask>(
memory_semantics_instruction->GetSingleWordInOperand(0));
if (memory_semantics_const_value !=
fuzzerutil::GetMemorySemanticsForStorageClass(
static_cast<spv::StorageClass>(
pointer_type->GetSingleWordInOperand(0)))) {
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 {
if (message_.is_atomic()) {
// OpAtomicLoad instruction.
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, spv::Op::OpAtomicLoad, result_type, message_.fresh_id(),
opt::Instruction::OperandList(
{{SPV_OPERAND_TYPE_ID, {message_.pointer_id()}},
{SPV_OPERAND_TYPE_SCOPE_ID, {message_.memory_scope_id()}},
{SPV_OPERAND_TYPE_MEMORY_SEMANTICS_ID,
{message_.memory_semantics_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));
} else {
// OpLoad instruction.
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, spv::Op::OpLoad, 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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