/*
 * Copyright (C) 2015 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_DEX2OAT_LINKER_RELATIVE_PATCHER_TEST_H_
#define ART_DEX2OAT_LINKER_RELATIVE_PATCHER_TEST_H_

#include <gtest/gtest.h>

#include "arch/instruction_set.h"
#include "arch/instruction_set_features.h"
#include "base/array_ref.h"
#include "base/globals.h"
#include "base/macros.h"
#include "compiled_method-inl.h"
#include "dex/method_reference.h"
#include "dex/string_reference.h"
#include "driver/compiled_method_storage.h"
#include "linker/relative_patcher.h"
#include "oat_quick_method_header.h"
#include "stream/vector_output_stream.h"

namespace art {
namespace linker {

// Base class providing infrastructure for architecture-specific tests.
class RelativePatcherTest : public testing::Test {
 protected:
  RelativePatcherTest(InstructionSet instruction_set, const std::string& variant)
      : storage_(/*swap_fd=*/ -1),
        instruction_set_(instruction_set),
        instruction_set_features_(nullptr),
        method_offset_map_(),
        patcher_(nullptr),
        bss_begin_(0u),
        compiled_method_refs_(),
        compiled_methods_(),
        patched_code_(),
        output_(),
        out_(nullptr) {
    std::string error_msg;
    instruction_set_features_ =
        InstructionSetFeatures::FromVariant(instruction_set, variant, &error_msg);
    CHECK(instruction_set_features_ != nullptr) << error_msg;

    patched_code_.reserve(16 * KB);
  }

  void SetUp() override {
    Reset();
  }

  void TearDown() override {
    thunk_provider_.Reset();
    compiled_methods_.clear();
    patcher_.reset();
    bss_begin_ = 0u;
    string_index_to_offset_map_.clear();
    compiled_method_refs_.clear();
    compiled_methods_.clear();
    patched_code_.clear();
    output_.clear();
    out_.reset();
  }

  // Reset the helper to start another test. Creating and tearing down the Runtime is expensive,
  // so we merge related tests together.
  void Reset() {
    thunk_provider_.Reset();
    method_offset_map_.map.clear();
    patcher_ = RelativePatcher::Create(instruction_set_,
                                       instruction_set_features_.get(),
                                       &thunk_provider_,
                                       &method_offset_map_);
    bss_begin_ = 0u;
    string_index_to_offset_map_.clear();
    compiled_method_refs_.clear();
    compiled_methods_.clear();
    patched_code_.clear();
    output_.clear();
    out_.reset(new VectorOutputStream("test output stream", &output_));
  }

  MethodReference MethodRef(uint32_t method_idx) {
    CHECK_NE(method_idx, 0u);
    return MethodReference(nullptr, method_idx);
  }

  void AddCompiledMethod(
      MethodReference method_ref,
      const ArrayRef<const uint8_t>& code,
      const ArrayRef<const LinkerPatch>& patches = ArrayRef<const LinkerPatch>()) {
    compiled_method_refs_.push_back(method_ref);
    compiled_methods_.emplace_back(new CompiledMethod(
        &storage_,
        instruction_set_,
        code,
        /* vmap_table */ ArrayRef<const uint8_t>(),
        /* cfi_info */ ArrayRef<const uint8_t>(),
        patches));
  }

  uint32_t CodeAlignmentSize(uint32_t header_offset_to_align) {
    // We want to align the code rather than the preheader.
    uint32_t unaligned_code_offset = header_offset_to_align + sizeof(OatQuickMethodHeader);
    uint32_t aligned_code_offset =
        CompiledMethod::AlignCode(unaligned_code_offset, instruction_set_);
    return aligned_code_offset - unaligned_code_offset;
  }

  void Link() {
    // Reserve space.
    static_assert(kTrampolineOffset == 0u, "Unexpected trampoline offset.");
    uint32_t offset = kTrampolineSize;
    size_t idx = 0u;
    for (auto& compiled_method : compiled_methods_) {
      offset = patcher_->ReserveSpace(offset, compiled_method.get(), compiled_method_refs_[idx]);

      uint32_t alignment_size = CodeAlignmentSize(offset);
      offset += alignment_size;

      offset += sizeof(OatQuickMethodHeader);
      uint32_t quick_code_offset = offset + compiled_method->CodeDelta();
      const auto code = compiled_method->GetQuickCode();
      offset += code.size();

      method_offset_map_.map.Put(compiled_method_refs_[idx], quick_code_offset);
      ++idx;
    }
    offset = patcher_->ReserveSpaceEnd(offset);
    uint32_t output_size = offset;
    output_.reserve(output_size);

    // Write data.
    DCHECK(output_.empty());
    uint8_t fake_trampoline[kTrampolineSize];
    memset(fake_trampoline, 0, sizeof(fake_trampoline));
    out_->WriteFully(fake_trampoline, kTrampolineSize);
    offset = kTrampolineSize;
    static const uint8_t kPadding[] = {
        0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u
    };
    uint8_t fake_header[sizeof(OatQuickMethodHeader)];
    memset(fake_header, 0, sizeof(fake_header));
    for (auto& compiled_method : compiled_methods_) {
      offset = patcher_->WriteThunks(out_.get(), offset);

      uint32_t alignment_size = CodeAlignmentSize(offset);
      CHECK_LE(alignment_size, sizeof(kPadding));
      out_->WriteFully(kPadding, alignment_size);
      offset += alignment_size;

      out_->WriteFully(fake_header, sizeof(OatQuickMethodHeader));
      offset += sizeof(OatQuickMethodHeader);
      ArrayRef<const uint8_t> code = compiled_method->GetQuickCode();
      if (!compiled_method->GetPatches().empty()) {
        patched_code_.assign(code.begin(), code.end());
        code = ArrayRef<const uint8_t>(patched_code_);
        for (const LinkerPatch& patch : compiled_method->GetPatches()) {
          if (patch.GetType() == LinkerPatch::Type::kCallRelative) {
            auto result = method_offset_map_.FindMethodOffset(patch.TargetMethod());
            uint32_t target_offset =
                result.first ? result.second : kTrampolineOffset + compiled_method->CodeDelta();
            patcher_->PatchCall(&patched_code_,
                                patch.LiteralOffset(),
                                offset + patch.LiteralOffset(),
                                target_offset);
          } else if (patch.GetType() == LinkerPatch::Type::kStringBssEntry) {
            uint32_t target_offset =
                bss_begin_ + string_index_to_offset_map_.Get(patch.TargetStringIndex().index_);
            patcher_->PatchPcRelativeReference(&patched_code_,
                                               patch,
                                               offset + patch.LiteralOffset(),
                                               target_offset);
          } else if (patch.GetType() == LinkerPatch::Type::kStringRelative) {
            uint32_t target_offset =
                string_index_to_offset_map_.Get(patch.TargetStringIndex().index_);
            patcher_->PatchPcRelativeReference(&patched_code_,
                                               patch,
                                               offset + patch.LiteralOffset(),
                                               target_offset);
          } else if (patch.GetType() == LinkerPatch::Type::kCallEntrypoint) {
            patcher_->PatchEntrypointCall(&patched_code_,
                                          patch,
                                          offset + patch.LiteralOffset());
          } else if (patch.GetType() == LinkerPatch::Type::kBakerReadBarrierBranch) {
            patcher_->PatchBakerReadBarrierBranch(&patched_code_,
                                                  patch,
                                                  offset + patch.LiteralOffset());
          } else {
            LOG(FATAL) << "Bad patch type. " << patch.GetType();
            UNREACHABLE();
          }
        }
      }
      out_->WriteFully(&code[0], code.size());
      offset += code.size();
    }
    offset = patcher_->WriteThunks(out_.get(), offset);
    CHECK_EQ(offset, output_size);
    CHECK_EQ(output_.size(), output_size);
  }

  bool CheckLinkedMethod(MethodReference method_ref, const ArrayRef<const uint8_t>& expected_code) {
    // Check that the original code size must match linked_code.size().
    size_t idx = 0u;
    for (auto ref : compiled_method_refs_) {
      if (ref == method_ref) {
        break;
      }
      ++idx;
    }
    CHECK_NE(idx, compiled_method_refs_.size());
    CHECK_EQ(compiled_methods_[idx]->GetQuickCode().size(), expected_code.size());

    auto result = method_offset_map_.FindMethodOffset(method_ref);
    CHECK(result.first);  // Must have been linked.
    size_t offset = result.second - compiled_methods_[idx]->CodeDelta();
    CHECK_LT(offset, output_.size());
    CHECK_LE(offset + expected_code.size(), output_.size());
    ArrayRef<const uint8_t> linked_code(&output_[offset], expected_code.size());
    if (linked_code == expected_code) {
      return true;
    }
    // Log failure info.
    DumpDiff(expected_code, linked_code);
    return false;
  }

  void DumpDiff(const ArrayRef<const uint8_t>& expected_code,
                const ArrayRef<const uint8_t>& linked_code) {
    std::ostringstream expected_hex;
    std::ostringstream linked_hex;
    std::ostringstream diff_indicator;
    static const char digits[] = "0123456789abcdef";
    bool found_diff = false;
    for (size_t i = 0; i != expected_code.size(); ++i) {
      expected_hex << " " << digits[expected_code[i] >> 4] << digits[expected_code[i] & 0xf];
      linked_hex << " " << digits[linked_code[i] >> 4] << digits[linked_code[i] & 0xf];
      if (!found_diff) {
        found_diff = (expected_code[i] != linked_code[i]);
        diff_indicator << (found_diff ? " ^^" : "   ");
      }
    }
    CHECK(found_diff);
    std::string expected_hex_str = expected_hex.str();
    std::string linked_hex_str = linked_hex.str();
    std::string diff_indicator_str = diff_indicator.str();
    if (diff_indicator_str.length() > 60) {
      CHECK_EQ(diff_indicator_str.length() % 3u, 0u);
      size_t remove = diff_indicator_str.length() / 3 - 5;
      std::ostringstream oss;
      oss << "[stripped " << remove << "]";
      std::string replacement = oss.str();
      expected_hex_str.replace(0u, remove * 3u, replacement);
      linked_hex_str.replace(0u, remove * 3u, replacement);
      diff_indicator_str.replace(0u, remove * 3u, replacement);
    }
    LOG(ERROR) << "diff expected_code linked_code";
    LOG(ERROR) << "<" << expected_hex_str;
    LOG(ERROR) << ">" << linked_hex_str;
    LOG(ERROR) << " " << diff_indicator_str;
  }

  class ThunkProvider : public RelativePatcherThunkProvider {
   public:
    ThunkProvider() {}

    void SetThunkCode(const LinkerPatch& patch,
                      ArrayRef<const uint8_t> code,
                      const std::string& debug_name) {
      thunk_map_.emplace(ThunkKey(patch), ThunkValue(code, debug_name));
    }

    void GetThunkCode(const LinkerPatch& patch,
                      /*out*/ ArrayRef<const uint8_t>* code,
                      /*out*/ std::string* debug_name) override {
      auto it = thunk_map_.find(ThunkKey(patch));
      CHECK(it != thunk_map_.end());
      const ThunkValue& value = it->second;
      CHECK(code != nullptr);
      *code = value.GetCode();
      CHECK(debug_name != nullptr);
      *debug_name = value.GetDebugName();
    }

    void Reset() {
      thunk_map_.clear();
    }

   private:
    class ThunkKey {
     public:
      explicit ThunkKey(const LinkerPatch& patch)
          : type_(patch.GetType()),
            custom_value1_(CustomValue1(patch)),
            custom_value2_(CustomValue2(patch)) {
        CHECK(patch.GetType() == LinkerPatch::Type::kCallEntrypoint ||
              patch.GetType() == LinkerPatch::Type::kBakerReadBarrierBranch ||
              patch.GetType() == LinkerPatch::Type::kCallRelative);
      }

      bool operator<(const ThunkKey& other) const {
        if (custom_value1_ != other.custom_value1_) {
          return custom_value1_ < other.custom_value1_;
        }
        if (custom_value2_ != other.custom_value2_) {
          return custom_value2_ < other.custom_value2_;
        }
        return type_ < other.type_;
      }

     private:
      static uint32_t CustomValue1(const LinkerPatch& patch) {
        switch (patch.GetType()) {
          case LinkerPatch::Type::kCallEntrypoint:
            return patch.EntrypointOffset();
          case LinkerPatch::Type::kBakerReadBarrierBranch:
            return patch.GetBakerCustomValue1();
          default:
            return 0;
        }
      }

      static uint32_t CustomValue2(const LinkerPatch& patch) {
        switch (patch.GetType()) {
          case LinkerPatch::Type::kBakerReadBarrierBranch:
            return patch.GetBakerCustomValue2();
          default:
            return 0;
        }
      }

      const LinkerPatch::Type type_;
      const uint32_t custom_value1_;
      const uint32_t custom_value2_;
    };

    class ThunkValue {
     public:
      ThunkValue(ArrayRef<const uint8_t> code, const std::string& debug_name)
          : code_(code.begin(), code.end()), debug_name_(debug_name) {}
      ArrayRef<const uint8_t> GetCode() const { return ArrayRef<const uint8_t>(code_); }
      const std::string& GetDebugName() const { return debug_name_; }

     private:
      const std::vector<uint8_t> code_;
      const std::string debug_name_;
    };

    std::map<ThunkKey, ThunkValue> thunk_map_;
  };

  // Map method reference to assinged offset.
  // Wrap the map in a class implementing RelativePatcherTargetProvider.
  class MethodOffsetMap final : public RelativePatcherTargetProvider {
   public:
    std::pair<bool, uint32_t> FindMethodOffset(MethodReference ref) override {
      auto it = map.find(ref);
      if (it == map.end()) {
        return std::pair<bool, uint32_t>(false, 0u);
      } else {
        return std::pair<bool, uint32_t>(true, it->second);
      }
    }
    SafeMap<MethodReference, uint32_t> map;
  };

  static const uint32_t kTrampolineSize = 4u;
  static const uint32_t kTrampolineOffset = 0u;

  CompiledMethodStorage storage_;
  InstructionSet instruction_set_;
  std::unique_ptr<const InstructionSetFeatures> instruction_set_features_;

  ThunkProvider thunk_provider_;
  MethodOffsetMap method_offset_map_;
  std::unique_ptr<RelativePatcher> patcher_;
  uint32_t bss_begin_;
  SafeMap<uint32_t, uint32_t> string_index_to_offset_map_;
  std::vector<MethodReference> compiled_method_refs_;
  std::vector<std::unique_ptr<CompiledMethod>> compiled_methods_;
  std::vector<uint8_t> patched_code_;
  std::vector<uint8_t> output_;
  std::unique_ptr<VectorOutputStream> out_;
};

}  // namespace linker
}  // namespace art

#endif  // ART_DEX2OAT_LINKER_RELATIVE_PATCHER_TEST_H_