/*
 * Copyright (C) 2013 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 "trampoline_compiler.h"

#include "base/arena_allocator.h"
#include "base/malloc_arena_pool.h"
#include "jni/jni_env_ext.h"

#ifdef ART_ENABLE_CODEGEN_arm
#include "utils/arm/assembler_arm_vixl.h"
#endif

#ifdef ART_ENABLE_CODEGEN_arm64
#include "utils/arm64/assembler_arm64.h"
#endif

#ifdef ART_ENABLE_CODEGEN_x86
#include "utils/x86/assembler_x86.h"
#endif

#ifdef ART_ENABLE_CODEGEN_x86_64
#include "utils/x86_64/assembler_x86_64.h"
#endif

#define __ assembler.

namespace art {

#ifdef ART_ENABLE_CODEGEN_arm
namespace arm {

#ifdef ___
#error "ARM Assembler macro already defined."
#else
#define ___ assembler.GetVIXLAssembler()->
#endif

static std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline(
    ArenaAllocator* allocator, EntryPointCallingConvention abi, ThreadOffset32 offset) {
  using vixl::aarch32::MemOperand;
  using vixl::aarch32::pc;
  using vixl::aarch32::r0;
  ArmVIXLAssembler assembler(allocator);

  switch (abi) {
    case kInterpreterAbi:  // Thread* is first argument (R0) in interpreter ABI.
      ___ Ldr(pc, MemOperand(r0, offset.Int32Value()));
      break;
    case kJniAbi: {  // Load via Thread* held in JNIEnv* in first argument (R0).
      vixl::aarch32::UseScratchRegisterScope temps(assembler.GetVIXLAssembler());
      const vixl::aarch32::Register temp_reg = temps.Acquire();

      // VIXL will use the destination as a scratch register if
      // the offset is not encodable as an immediate operand.
      ___ Ldr(temp_reg, MemOperand(r0, JNIEnvExt::SelfOffset(4).Int32Value()));
      ___ Ldr(pc, MemOperand(temp_reg, offset.Int32Value()));
      break;
    }
    case kQuickAbi:  // TR holds Thread*.
      ___ Ldr(pc, MemOperand(tr, offset.Int32Value()));
  }

  __ FinalizeCode();
  size_t cs = __ CodeSize();
  std::unique_ptr<std::vector<uint8_t>> entry_stub(new std::vector<uint8_t>(cs));
  MemoryRegion code(entry_stub->data(), entry_stub->size());
  __ FinalizeInstructions(code);

  return std::move(entry_stub);
}

#undef ___

}  // namespace arm
#endif  // ART_ENABLE_CODEGEN_arm

#ifdef ART_ENABLE_CODEGEN_arm64
namespace arm64 {
static std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline(
    ArenaAllocator* allocator, EntryPointCallingConvention abi, ThreadOffset64 offset) {
  Arm64Assembler assembler(allocator);

  switch (abi) {
    case kInterpreterAbi:  // Thread* is first argument (X0) in interpreter ABI.
      __ JumpTo(Arm64ManagedRegister::FromXRegister(X0), Offset(offset.Int32Value()),
          Arm64ManagedRegister::FromXRegister(IP1));

      break;
    case kJniAbi:  // Load via Thread* held in JNIEnv* in first argument (X0).
      __ LoadRawPtr(Arm64ManagedRegister::FromXRegister(IP1),
                      Arm64ManagedRegister::FromXRegister(X0),
                      Offset(JNIEnvExt::SelfOffset(8).Int32Value()));

      __ JumpTo(Arm64ManagedRegister::FromXRegister(IP1), Offset(offset.Int32Value()),
                Arm64ManagedRegister::FromXRegister(IP0));

      break;
    case kQuickAbi:  // X18 holds Thread*.
      __ JumpTo(Arm64ManagedRegister::FromXRegister(TR), Offset(offset.Int32Value()),
                Arm64ManagedRegister::FromXRegister(IP0));

      break;
  }

  __ FinalizeCode();
  size_t cs = __ CodeSize();
  std::unique_ptr<std::vector<uint8_t>> entry_stub(new std::vector<uint8_t>(cs));
  MemoryRegion code(entry_stub->data(), entry_stub->size());
  __ FinalizeInstructions(code);

  return std::move(entry_stub);
}
}  // namespace arm64
#endif  // ART_ENABLE_CODEGEN_arm64

#ifdef ART_ENABLE_CODEGEN_x86
namespace x86 {
static std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline(ArenaAllocator* allocator,
                                                                    ThreadOffset32 offset) {
  X86Assembler assembler(allocator);

  // All x86 trampolines call via the Thread* held in fs.
  __ fs()->jmp(Address::Absolute(offset));
  __ int3();

  __ FinalizeCode();
  size_t cs = __ CodeSize();
  std::unique_ptr<std::vector<uint8_t>> entry_stub(new std::vector<uint8_t>(cs));
  MemoryRegion code(entry_stub->data(), entry_stub->size());
  __ FinalizeInstructions(code);

  return std::move(entry_stub);
}
}  // namespace x86
#endif  // ART_ENABLE_CODEGEN_x86

#ifdef ART_ENABLE_CODEGEN_x86_64
namespace x86_64 {
static std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline(ArenaAllocator* allocator,
                                                                    ThreadOffset64 offset) {
  x86_64::X86_64Assembler assembler(allocator);

  // All x86 trampolines call via the Thread* held in gs.
  __ gs()->jmp(x86_64::Address::Absolute(offset, true));
  __ int3();

  __ FinalizeCode();
  size_t cs = __ CodeSize();
  std::unique_ptr<std::vector<uint8_t>> entry_stub(new std::vector<uint8_t>(cs));
  MemoryRegion code(entry_stub->data(), entry_stub->size());
  __ FinalizeInstructions(code);

  return std::move(entry_stub);
}
}  // namespace x86_64
#endif  // ART_ENABLE_CODEGEN_x86_64

std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline64(InstructionSet isa,
                                                               EntryPointCallingConvention abi,
                                                               ThreadOffset64 offset) {
  MallocArenaPool pool;
  ArenaAllocator allocator(&pool);
  switch (isa) {
#ifdef ART_ENABLE_CODEGEN_arm64
    case InstructionSet::kArm64:
      return arm64::CreateTrampoline(&allocator, abi, offset);
#endif
#ifdef ART_ENABLE_CODEGEN_x86_64
    case InstructionSet::kX86_64:
      return x86_64::CreateTrampoline(&allocator, offset);
#endif
    default:
      UNUSED(abi);
      UNUSED(offset);
      LOG(FATAL) << "Unexpected InstructionSet: " << isa;
      UNREACHABLE();
  }
}

std::unique_ptr<const std::vector<uint8_t>> CreateTrampoline32(InstructionSet isa,
                                                               EntryPointCallingConvention abi,
                                                               ThreadOffset32 offset) {
  MallocArenaPool pool;
  ArenaAllocator allocator(&pool);
  switch (isa) {
#ifdef ART_ENABLE_CODEGEN_arm
    case InstructionSet::kArm:
    case InstructionSet::kThumb2:
      return arm::CreateTrampoline(&allocator, abi, offset);
#endif
#ifdef ART_ENABLE_CODEGEN_x86
    case InstructionSet::kX86:
      UNUSED(abi);
      return x86::CreateTrampoline(&allocator, offset);
#endif
    default:
      LOG(FATAL) << "Unexpected InstructionSet: " << isa;
      UNREACHABLE();
  }
}

}  // namespace art