/*
 * Copyright (C) 2011 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.
 */

#ifndef ART_RUNTIME_CHECK_REFERENCE_MAP_VISITOR_H_
#define ART_RUNTIME_CHECK_REFERENCE_MAP_VISITOR_H_

#include "art_method-inl.h"
#include "gc_map.h"
#include "scoped_thread_state_change.h"
#include "stack_map.h"

namespace art {

// Helper class for tests checking that the compiler keeps track of dex registers
// holding references.
class CheckReferenceMapVisitor : public StackVisitor {
 public:
  explicit CheckReferenceMapVisitor(Thread* thread) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
      : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames) {}

  bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    ArtMethod* m = GetMethod();
    if (m->IsCalleeSaveMethod() || m->IsNative()) {
      CHECK_EQ(GetDexPc(), DexFile::kDexNoIndex);
    }

    if (m == nullptr || m->IsNative() || m->IsRuntimeMethod() || IsShadowFrame()) {
      return true;
    }

    LOG(INFO) << "At " << PrettyMethod(m, false);

    if (m->IsCalleeSaveMethod()) {
      LOG(WARNING) << "no PC for " << PrettyMethod(m);
      return true;
    }

    return false;
  }

  void CheckReferences(int* registers, int number_of_references, uint32_t native_pc_offset)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    if (GetMethod()->IsOptimized(sizeof(void*))) {
      CheckOptimizedMethod(registers, number_of_references, native_pc_offset);
    } else {
      CheckQuickMethod(registers, number_of_references, native_pc_offset);
    }
  }

 private:
  void CheckOptimizedMethod(int* registers, int number_of_references, uint32_t native_pc_offset)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    ArtMethod* m = GetMethod();
    CodeInfo code_info = m->GetOptimizedCodeInfo();
    StackMapEncoding encoding = code_info.ExtractEncoding();
    StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset, encoding);
    uint16_t number_of_dex_registers = m->GetCodeItem()->registers_size_;
    DexRegisterMap dex_register_map =
        code_info.GetDexRegisterMapOf(stack_map, encoding, number_of_dex_registers);
    MemoryRegion stack_mask = stack_map.GetStackMask(encoding);
    uint32_t register_mask = stack_map.GetRegisterMask(encoding);
    for (int i = 0; i < number_of_references; ++i) {
      int reg = registers[i];
      CHECK(reg < m->GetCodeItem()->registers_size_);
      DexRegisterLocation location = dex_register_map.GetDexRegisterLocation(
          reg, number_of_dex_registers, code_info, encoding);
      switch (location.GetKind()) {
        case DexRegisterLocation::Kind::kNone:
          // Not set, should not be a reference.
          CHECK(false);
          break;
        case DexRegisterLocation::Kind::kInStack:
          DCHECK_EQ(location.GetValue() % kFrameSlotSize, 0);
          CHECK(stack_mask.LoadBit(location.GetValue() / kFrameSlotSize));
          break;
        case DexRegisterLocation::Kind::kInRegister:
          CHECK_NE(register_mask & (1 << location.GetValue()), 0u);
          break;
        case DexRegisterLocation::Kind::kInFpuRegister:
          // In Fpu register, should not be a reference.
          CHECK(false);
          break;
        case DexRegisterLocation::Kind::kConstant:
          CHECK_EQ(location.GetValue(), 0);
          break;
        default:
          LOG(FATAL) << "Unexpected location kind"
                     << DexRegisterLocation::PrettyDescriptor(location.GetInternalKind());
      }
    }
  }

  void CheckQuickMethod(int* registers, int number_of_references, uint32_t native_pc_offset)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    ArtMethod* m = GetMethod();
    NativePcOffsetToReferenceMap map(m->GetNativeGcMap(sizeof(void*)));
    const uint8_t* ref_bitmap = map.FindBitMap(native_pc_offset);
    CHECK(ref_bitmap);
    for (int i = 0; i < number_of_references; ++i) {
      int reg = registers[i];
      CHECK(reg < m->GetCodeItem()->registers_size_);
      CHECK((*((ref_bitmap) + reg / 8) >> (reg % 8) ) & 0x01)
          << "Error: Reg @" << i << " is not in GC map";
    }
  }
};

}  // namespace art

#endif  // ART_RUNTIME_CHECK_REFERENCE_MAP_VISITOR_H_