/*
 * Copyright (C) 2023 The Android Open Source Project
 *
 * 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 "gtest/gtest.h"

#include "berberis/backend/x86_64/local_guest_context_optimizer.h"

#include "berberis/backend/x86_64/machine_ir.h"
#include "berberis/backend/x86_64/machine_ir_builder.h"
#include "berberis/backend/x86_64/machine_ir_check.h"
#include "berberis/base/arena_alloc.h"
#include "berberis/guest_state/guest_addr.h"
#include "berberis/guest_state/guest_state.h"

namespace berberis {

namespace {

TEST(MachineIRLocalGuestContextOptimizer, RemoveReadAfterWrite) {
  Arena arena;
  x86_64::MachineIR machine_ir(&arena);

  x86_64::MachineIRBuilder builder(&machine_ir);

  auto bb = machine_ir.NewBasicBlock();
  builder.StartBasicBlock(bb);
  auto reg1 = machine_ir.AllocVReg();
  auto reg2 = machine_ir.AllocVReg();
  builder.GenPut(GetThreadStateRegOffset(0), reg1);
  builder.GenGet(reg2, GetThreadStateRegOffset(0));
  builder.Gen<PseudoJump>(kNullGuestAddr);

  x86_64::RemoveLocalGuestContextAccesses(&machine_ir);
  ASSERT_EQ(x86_64::CheckMachineIR(machine_ir), x86_64::kMachineIRCheckSuccess);

  ASSERT_EQ(bb->insn_list().size(), 3UL);

  auto* store_insn = *bb->insn_list().begin();
  ASSERT_EQ(store_insn->opcode(), kMachineOpMovqMemBaseDispReg);
  auto disp = x86_64::AsMachineInsnX86_64(store_insn)->disp();
  ASSERT_EQ(disp, berberis::GetThreadStateRegOffset(0));
  auto replaced_reg = store_insn->RegAt(1);
  ASSERT_EQ(store_insn->RegAt(0), x86_64::kMachineRegRBP);

  auto* load_copy_insn = *std::next(bb->insn_list().begin());
  ASSERT_EQ(load_copy_insn->opcode(), kMachineOpPseudoCopy);
  ASSERT_EQ(load_copy_insn->RegAt(0), reg2);
  ASSERT_EQ(load_copy_insn->RegAt(1), replaced_reg);
}

TEST(MachineIRLocalGuestContextOptimizer, RemoveReadAfterRead) {
  Arena arena;
  x86_64::MachineIR machine_ir(&arena);

  x86_64::MachineIRBuilder builder(&machine_ir);

  auto bb = machine_ir.NewBasicBlock();
  builder.StartBasicBlock(bb);
  auto reg1 = machine_ir.AllocVReg();
  auto reg2 = machine_ir.AllocVReg();
  builder.GenGet(reg1, GetThreadStateRegOffset(0));
  builder.GenGet(reg2, GetThreadStateRegOffset(0));
  builder.Gen<PseudoJump>(kNullGuestAddr);

  x86_64::RemoveLocalGuestContextAccesses(&machine_ir);
  ASSERT_EQ(x86_64::CheckMachineIR(machine_ir), x86_64::kMachineIRCheckSuccess);

  ASSERT_EQ(bb->insn_list().size(), 3UL);
  auto* load_insn = *bb->insn_list().begin();
  ASSERT_EQ(load_insn->opcode(), kMachineOpMovqRegMemBaseDisp);
  ASSERT_EQ(x86_64::AsMachineInsnX86_64(load_insn)->disp(), berberis::GetThreadStateRegOffset(0));
  ASSERT_EQ(load_insn->RegAt(0), reg1);
  ASSERT_EQ(load_insn->RegAt(1), x86_64::kMachineRegRBP);

  auto* copy_insn = *std::next(bb->insn_list().begin());
  ASSERT_EQ(copy_insn->opcode(), kMachineOpPseudoCopy);
  ASSERT_EQ(copy_insn->RegAt(0), reg2);
  ASSERT_EQ(copy_insn->RegAt(1), reg1);
}

TEST(MachineIRLocalGuestContextOptimizer, RemoveWriteAfterWrite) {
  Arena arena;
  x86_64::MachineIR machine_ir(&arena);

  x86_64::MachineIRBuilder builder(&machine_ir);

  auto bb = machine_ir.NewBasicBlock();
  builder.StartBasicBlock(bb);
  auto reg1 = machine_ir.AllocVReg();
  auto reg2 = machine_ir.AllocVReg();
  builder.GenPut(GetThreadStateRegOffset(0), reg1);
  builder.GenPut(GetThreadStateRegOffset(0), reg2);
  builder.Gen<PseudoJump>(kNullGuestAddr);

  x86_64::RemoveLocalGuestContextAccesses(&machine_ir);
  ASSERT_EQ(x86_64::CheckMachineIR(machine_ir), x86_64::kMachineIRCheckSuccess);

  ASSERT_EQ(bb->insn_list().size(), 2UL);
  auto* store_insn = *bb->insn_list().begin();
  ASSERT_EQ(store_insn->opcode(), kMachineOpMovqMemBaseDispReg);
  ASSERT_EQ(x86_64::AsMachineInsnX86_64(store_insn)->disp(), berberis::GetThreadStateRegOffset(0));
  ASSERT_EQ(store_insn->RegAt(1), reg2);
  ASSERT_EQ(store_insn->RegAt(0), x86_64::kMachineRegRBP);
}

TEST(MachineIRLocalGuestContextOptimizer, DoNotRemoveAccessToMonitorValue) {
  Arena arena;
  x86_64::MachineIR machine_ir(&arena);

  x86_64::MachineIRBuilder builder(&machine_ir);

  auto bb = machine_ir.NewBasicBlock();
  builder.StartBasicBlock(bb);
  auto reg1 = machine_ir.AllocVReg();
  auto reg2 = machine_ir.AllocVReg();
  auto offset = offsetof(ProcessState, cpu.reservation_value);
  builder.Gen<x86_64::MovqMemBaseDispReg>(x86_64::kMachineRegRBP, offset, reg1);
  builder.Gen<x86_64::MovqMemBaseDispReg>(x86_64::kMachineRegRBP, offset, reg2);
  builder.Gen<PseudoJump>(kNullGuestAddr);

  x86_64::RemoveLocalGuestContextAccesses(&machine_ir);
  ASSERT_EQ(x86_64::CheckMachineIR(machine_ir), x86_64::kMachineIRCheckSuccess);

  ASSERT_EQ(bb->insn_list().size(), 3UL);
  auto* store_insn_1 = *bb->insn_list().begin();
  ASSERT_EQ(store_insn_1->opcode(), kMachineOpMovqMemBaseDispReg);
  ASSERT_EQ(x86_64::AsMachineInsnX86_64(store_insn_1)->disp(), offset);

  auto* store_insn_2 = *std::next(bb->insn_list().begin());
  ASSERT_EQ(store_insn_2->opcode(), kMachineOpMovqMemBaseDispReg);
  ASSERT_EQ(x86_64::AsMachineInsnX86_64(store_insn_2)->disp(), offset);
}

}  // namespace

}  // namespace berberis