Enable MSVC W4 with a few exceptions. Fix warnings and bugs

Summary: Closes https://github.com/facebook/rocksdb/pull/3018

Differential Revision: D6079011

Pulled By: yiwu-arbug

fbshipit-source-id: 988a721e7e7617967859dba71d660fc69f4dff57

CMakeLists.txt

@@ -145,7 +145,7 @@ target_include_directories(build_version PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}/util)
 if(MSVC)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi /nologo /EHsc /GS /Gd /GR /GF /fp:precise /Zc:wchar_t /Zc:forScope /errorReport:queue")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /wd4127 /wd4800 /wd4996 /wd4351")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W4 /wd4127 /wd4800 /wd4996 /wd4351 /wd4100 /wd4204 /wd4324")
 else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -W -Wextra -Wall")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -Wno-strict-aliasing")
@@ -560,10 +560,12 @@ set(SOURCES
         $<TARGET_OBJECTS:build_version>)
 
 if(HAVE_SSE42 AND NOT FORCE_SSE42)
+  if(NOT MSVC)
 set_source_files_properties(
   util/crc32c.cc
       PROPERTIES COMPILE_FLAGS "-msse4.2")
   endif()
+endif()
 
 if(WIN32)
   list(APPEND SOURCES

db/cuckoo_table_db_test.cc

@@ -241,7 +241,7 @@ TEST_F(CuckooTableDBTest, CompactionIntoMultipleFiles) {
 
   // Write 28 values, each 10016 B ~ 10KB
   for (int idx = 0; idx < 28; ++idx) {
-    ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + idx)));
+    ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + char(idx))));
   }
   dbfull()->TEST_WaitForFlushMemTable();
   ASSERT_EQ("1", FilesPerLevel());
@@ -250,7 +250,7 @@ TEST_F(CuckooTableDBTest, CompactionIntoMultipleFiles) {
                               true /* disallow trivial move */);
   ASSERT_EQ("0,2", FilesPerLevel());
   for (int idx = 0; idx < 28; ++idx) {
-    ASSERT_EQ(std::string(10000, 'a' + idx), Get(Key(idx)));
+    ASSERT_EQ(std::string(10000, 'a' + char(idx)), Get(Key(idx)));
   }
 }
 
@@ -271,14 +271,14 @@ TEST_F(CuckooTableDBTest, SameKeyInsertedInTwoDifferentFilesAndCompacted) {
 
   // Generate one more file in level-0, and should trigger level-0 compaction
   for (int idx = 0; idx < 11; ++idx) {
-    ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + idx)));
+    ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + char(idx))));
   }
   dbfull()->TEST_WaitForFlushMemTable();
   dbfull()->TEST_CompactRange(0, nullptr, nullptr);
 
   ASSERT_EQ("0,1", FilesPerLevel());
   for (int idx = 0; idx < 11; ++idx) {
-    ASSERT_EQ(std::string(10000, 'a' + idx), Get(Key(idx)));
+    ASSERT_EQ(std::string(10000, 'a' + char(idx)), Get(Key(idx)));
   }
 }
 

db/db_basic_test.cc

@@ -41,7 +41,7 @@ TEST_F(DBBasicTest, ReadOnlyDB) {
   Close();
 
   auto options = CurrentOptions();
-  assert(options.env = env_);
+  assert(options.env == env_);
   ASSERT_OK(ReadOnlyReopen(options));
   ASSERT_EQ("v3", Get("foo"));
   ASSERT_EQ("v2", Get("bar"));

db/db_compaction_filter_test.cc

@@ -308,7 +308,6 @@ TEST_F(DBTestCompactionFilter, CompactionFilter) {
     ASSERT_OK(iter->status());
     while (iter->Valid()) {
       ParsedInternalKey ikey(Slice(), 0, kTypeValue);
-      ikey.sequence = -1;
       ASSERT_EQ(ParseInternalKey(iter->key(), &ikey), true);
       total++;
       if (ikey.sequence != 0) {
@@ -617,7 +616,6 @@ TEST_F(DBTestCompactionFilter, CompactionFilterContextManual) {
     ASSERT_OK(iter->status());
     while (iter->Valid()) {
       ParsedInternalKey ikey(Slice(), 0, kTypeValue);
-      ikey.sequence = -1;
       ASSERT_EQ(ParseInternalKey(iter->key(), &ikey), true);
       total++;
       if (ikey.sequence != 0) {

db/db_impl.cc

@@ -1411,6 +1411,7 @@ bool DBImpl::KeyMayExist(const ReadOptions& read_options,
 
 Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
                               ColumnFamilyHandle* column_family) {
+  Iterator* result = nullptr;
   if (read_options.read_tier == kPersistedTier) {
     return NewErrorIterator(Status::NotSupported(
         "ReadTier::kPersistedData is not yet supported in iterators."));
@@ -1421,25 +1422,27 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
   if (read_options.managed) {
 #ifdef ROCKSDB_LITE
     // not supported in lite version
-    return NewErrorIterator(Status::InvalidArgument(
+    result =  NewErrorIterator(Status::InvalidArgument(
         "Managed Iterators not supported in RocksDBLite."));
 #else
     if ((read_options.tailing) || (read_options.snapshot != nullptr) ||
         (is_snapshot_supported_)) {
-      return new ManagedIterator(this, read_options, cfd);
+      result = new ManagedIterator(this, read_options, cfd);
-    }
+    } else {
       // Managed iter not supported
-    return NewErrorIterator(Status::InvalidArgument(
+      result = NewErrorIterator(Status::InvalidArgument(
         "Managed Iterators not supported without snapshots."));
+    }
 #endif
   } else if (read_options.tailing) {
 #ifdef ROCKSDB_LITE
     // not supported in lite version
-    return nullptr;
+    result = nullptr;
+
 #else
     SuperVersion* sv = cfd->GetReferencedSuperVersion(&mutex_);
     auto iter = new ForwardIterator(this, read_options, cfd, sv);
-    return NewDBIterator(
+    result = NewDBIterator(
         env_, read_options, *cfd->ioptions(), cfd->user_comparator(), iter,
         kMaxSequenceNumber,
         sv->mutable_cf_options.max_sequential_skip_in_iterations,
@@ -1449,10 +1452,9 @@ Iterator* DBImpl::NewIterator(const ReadOptions& read_options,
     auto snapshot = read_options.snapshot != nullptr
                         ? read_options.snapshot->GetSequenceNumber()
                         : versions_->LastSequence();
-    return NewIteratorImpl(read_options, cfd, snapshot, read_callback);
+    result = NewIteratorImpl(read_options, cfd, snapshot, read_callback);
   }
-  // To stop compiler from complaining
+  return result;
-  return nullptr;
 }
 
 ArenaWrappedDBIter* DBImpl::NewIteratorImpl(const ReadOptions& read_options,

db/db_impl_compaction_flush.cc

@@ -894,15 +894,15 @@ Status DBImpl::RunManualCompaction(ColumnFamilyData* cfd, int input_level,
   while (!manual.done) {
     assert(HasPendingManualCompaction());
     manual_conflict = false;
-    Compaction* compaction;
+    Compaction* compaction = nullptr;
     if (ShouldntRunManualCompaction(&manual) || (manual.in_progress == true) ||
         scheduled ||
-        ((manual.manual_end = &manual.tmp_storage1) &&
+        (((manual.manual_end = &manual.tmp_storage1) != nullptr) &&
              ((compaction = manual.cfd->CompactRange(
                   *manual.cfd->GetLatestMutableCFOptions(), manual.input_level,
                   manual.output_level, manual.output_path_id, manual.begin,
-               manual.end, &manual.manual_end, &manual_conflict)) == nullptr) &&
+                  manual.end, &manual.manual_end, &manual_conflict)) == nullptr &&
-         manual_conflict)) {
+         manual_conflict))) {
       // exclusive manual compactions should not see a conflict during
       // CompactRange
       assert(!exclusive || !manual_conflict);

db/db_iter.cc

@@ -139,7 +139,9 @@ class DBIter final: public Iterator {
     if (pinned_iters_mgr_.PinningEnabled()) {
       pinned_iters_mgr_.ReleasePinnedData();
     }
-    RecordTick(statistics_, NO_ITERATORS, -1);
+    // Compiler warning issue filed:
+    // https://github.com/facebook/rocksdb/issues/3013
+    RecordTick(statistics_, NO_ITERATORS, uint64_t(-1));
     local_stats_.BumpGlobalStatistics(statistics_);
     if (!arena_mode_) {
       delete iter_;

db/db_test_util.cc

@@ -1169,7 +1169,7 @@ void DBTestBase::validateNumberOfEntries(int numValues, int cf) {
   int seq = numValues;
   while (iter->Valid()) {
     ParsedInternalKey ikey;
-    ikey.sequence = -1;
+    ikey.clear();
     ASSERT_EQ(ParseInternalKey(iter->key(), &ikey), true);
 
     // checks sequence number for updates

db/log_test.cc

@@ -195,7 +195,7 @@ class LogTest : public ::testing::TestWithParam<int> {
     }
   }
 
-  void IncrementByte(int offset, int delta) {
+  void IncrementByte(int offset, char delta) {
     dest_contents()[offset] += delta;
   }
 
@@ -487,7 +487,7 @@ TEST_P(LogTest, ChecksumMismatch) {
 
 TEST_P(LogTest, UnexpectedMiddleType) {
   Write("foo");
-  SetByte(6, GetParam() ? kRecyclableMiddleType : kMiddleType);
+  SetByte(6, static_cast<char>(GetParam() ? kRecyclableMiddleType : kMiddleType));
   FixChecksum(0, 3, !!GetParam());
   ASSERT_EQ("EOF", Read());
   ASSERT_EQ(3U, DroppedBytes());
@@ -496,7 +496,7 @@ TEST_P(LogTest, UnexpectedMiddleType) {
 
 TEST_P(LogTest, UnexpectedLastType) {
   Write("foo");
-  SetByte(6, GetParam() ? kRecyclableLastType : kLastType);
+  SetByte(6, static_cast<char>(GetParam() ? kRecyclableLastType : kLastType));
   FixChecksum(0, 3, !!GetParam());
   ASSERT_EQ("EOF", Read());
   ASSERT_EQ(3U, DroppedBytes());
@@ -506,7 +506,7 @@ TEST_P(LogTest, UnexpectedLastType) {
 TEST_P(LogTest, UnexpectedFullType) {
   Write("foo");
   Write("bar");
-  SetByte(6, GetParam() ? kRecyclableFirstType : kFirstType);
+  SetByte(6, static_cast<char>(GetParam() ? kRecyclableFirstType : kFirstType));
   FixChecksum(0, 3, !!GetParam());
   ASSERT_EQ("bar", Read());
   ASSERT_EQ("EOF", Read());
@@ -517,7 +517,7 @@ TEST_P(LogTest, UnexpectedFullType) {
 TEST_P(LogTest, UnexpectedFirstType) {
   Write("foo");
   Write(BigString("bar", 100000));
-  SetByte(6, GetParam() ? kRecyclableFirstType : kFirstType);
+  SetByte(6, static_cast<char>(GetParam() ? kRecyclableFirstType : kFirstType));
   FixChecksum(0, 3, !!GetParam());
   ASSERT_EQ(BigString("bar", 100000), Read());
   ASSERT_EQ("EOF", Read());

db/write_batch_test.cc

@@ -418,7 +418,7 @@ TEST_F(WriteBatchTest, PrepareCommit) {
 TEST_F(WriteBatchTest, DISABLED_ManyUpdates) {
   // Insert key and value of 3GB and push total batch size to 12GB.
   static const size_t kKeyValueSize = 4u;
-  static const uint32_t kNumUpdates = 3 << 30;
+  static const uint32_t kNumUpdates = uint32_t(3 << 30);
   std::string raw(kKeyValueSize, 'A');
   WriteBatch batch(kNumUpdates * (4 + kKeyValueSize * 2) + 1024u);
   char c = 'A';

env/env_test.cc

@@ -73,7 +73,7 @@ struct Deleter {
 std::unique_ptr<char, Deleter> NewAligned(const size_t size, const char ch) {
   char* ptr = nullptr;
 #ifdef OS_WIN
-  if (!(ptr = reinterpret_cast<char*>(_aligned_malloc(size, kPageSize)))) {
+  if (nullptr == (ptr = reinterpret_cast<char*>(_aligned_malloc(size, kPageSize)))) {
     return std::unique_ptr<char, Deleter>(nullptr, Deleter(_aligned_free));
   }
   std::unique_ptr<char, Deleter> uptr(ptr, Deleter(_aligned_free));
@@ -701,7 +701,6 @@ TEST_F(EnvPosixTest, PositionedAppend) {
   IoctlFriendlyTmpdir ift;
   ASSERT_OK(env_->NewWritableFile(ift.name() + "/f", &writable_file, options));
   const size_t kBlockSize = 4096;
-  const size_t kPageSize = 4096;
   const size_t kDataSize = kPageSize;
   // Write a page worth of 'a'
   auto data_ptr = NewAligned(kDataSize, 'a');

include/rocksdb/filter_policy.h

@@ -46,6 +46,10 @@ class FilterBitsBuilder {
   virtual Slice Finish(std::unique_ptr<const char[]>* buf) = 0;
 
   // Calculate num of entries fit into a space.
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4702) // unreachable code
+#endif
   virtual int CalculateNumEntry(const uint32_t space) {
 #ifndef ROCKSDB_LITE
     throw std::runtime_error("CalculateNumEntry not Implemented");
@@ -54,6 +58,9 @@ class FilterBitsBuilder {
 #endif
     return 0;
   }
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 };
 
 // A class that checks if a key can be in filter

include/rocksdb/utilities/env_mirror.h

@@ -73,6 +73,11 @@ class EnvMirror : public EnvWrapper {
     assert(as == bs);
     return as;
   }
+#if defined(_MSC_VER)
+#pragma warning(push)
+// logical operation on address of string constant
+#pragma warning(disable : 4130)
+#endif
   Status GetChildren(const std::string& dir,
                      std::vector<std::string>* r) override {
     std::vector<std::string> ar, br;
@@ -87,6 +92,9 @@ class EnvMirror : public EnvWrapper {
     *r = ar;
     return as;
   }
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
   Status DeleteFile(const std::string& f) override {
     Status as = a_->DeleteFile(f);
     Status bs = b_->DeleteFile(f);

memtable/inlineskiplist.h

@@ -565,8 +565,8 @@ InlineSkipList<Comparator>::InlineSkipList(const Comparator cmp,
                                            Allocator* allocator,
                                            int32_t max_height,
                                            int32_t branching_factor)
-    : kMaxHeight_(max_height),
+    : kMaxHeight_(static_cast<uint16_t>(max_height)),
-      kBranching_(branching_factor),
+      kBranching_(static_cast<uint16_t>(branching_factor)),
       kScaledInverseBranching_((Random::kMaxNext + 1) / kBranching_),
       compare_(cmp),
       allocator_(allocator),

memtable/skiplist.h

@@ -409,8 +409,8 @@ template <typename Key, class Comparator>
 SkipList<Key, Comparator>::SkipList(const Comparator cmp, Allocator* allocator,
                                     int32_t max_height,
                                     int32_t branching_factor)
-    : kMaxHeight_(max_height),
+    : kMaxHeight_(static_cast<uint16_t>(max_height)),
-      kBranching_(branching_factor),
+      kBranching_(static_cast<uint16_t>(branching_factor)),
       kScaledInverseBranching_((Random::kMaxNext + 1) / kBranching_),
       compare_(cmp),
       allocator_(allocator),

port/win/io_win.cc

@@ -675,7 +675,6 @@ Status WinRandomAccessImpl::ReadImpl(uint64_t offset, size_t n, Slice* result,
   }
 
   size_t left = n;
-  char* dest = scratch;
 
   SSIZE_T r = PositionedReadInternal(scratch, left, offset);
   if (r > 0) {

table/cuckoo_table_builder.cc

@@ -187,7 +187,7 @@ Status CuckooTableBuilder::MakeHashTable(std::vector<CuckooBucket>* buckets) {
   buckets->resize(hash_table_size_ + cuckoo_block_size_ - 1);
   uint32_t make_space_for_key_call_id = 0;
   for (uint32_t vector_idx = 0; vector_idx < num_entries_; vector_idx++) {
-    uint64_t bucket_id;
+    uint64_t bucket_id = 0;
     bool bucket_found = false;
     autovector<uint64_t> hash_vals;
     Slice user_key = GetUserKey(vector_idx);

table/index_builder.cc

@@ -28,26 +28,28 @@ IndexBuilder* IndexBuilder::CreateIndexBuilder(
     const InternalKeyComparator* comparator,
     const InternalKeySliceTransform* int_key_slice_transform,
     const BlockBasedTableOptions& table_opt) {
+  IndexBuilder* result = nullptr;
   switch (index_type) {
     case BlockBasedTableOptions::kBinarySearch: {
-      return new ShortenedIndexBuilder(comparator,
+      result =  new ShortenedIndexBuilder(comparator,
                                        table_opt.index_block_restart_interval);
     }
+  break;
     case BlockBasedTableOptions::kHashSearch: {
-      return new HashIndexBuilder(comparator, int_key_slice_transform,
+      result = new HashIndexBuilder(comparator, int_key_slice_transform,
                                   table_opt.index_block_restart_interval);
     }
+  break;
     case BlockBasedTableOptions::kTwoLevelIndexSearch: {
-      return PartitionedIndexBuilder::CreateIndexBuilder(comparator, table_opt);
+      result = PartitionedIndexBuilder::CreateIndexBuilder(comparator, table_opt);
     }
+    break;
     default: {
       assert(!"Do not recognize the index type ");
-      return nullptr;
     }
+  break;
   }
-  // impossible.
+  return result;
-  assert(false);
-  return nullptr;
 }
 
 PartitionedIndexBuilder* PartitionedIndexBuilder::CreateIndexBuilder(

table/plain_table_factory.h

@@ -161,7 +161,7 @@ class PlainTableFactory : public TableFactory {
 
   const PlainTableOptions& table_options() const;
 
-  static const char kValueTypeSeqId0 = char(0xFF);
+  static const char kValueTypeSeqId0 = char(~0);
 
   // Sanitizes the specified DB Options.
   Status SanitizeOptions(const DBOptions& db_opts,

third-party/fbson/FbsonWriter.h

@@ -32,6 +32,13 @@
 #include "FbsonDocument.h"
 #include "FbsonStream.h"
 
+// conversion' conversion from 'type1' to 'type2', possible loss of data
+// Can not restore at the header end as the warnings are emitted at the point of
+// template instantiation
+#if defined(_MSC_VER)
+#pragma warning(disable : 4244)
+#endif
+
 namespace fbson {
 
 template <class OS_TYPE>

tools/db_bench_tool.cc

@@ -3365,7 +3365,7 @@ void VerifyDBFromDB(std::string& truth_db_name) {
         db->db = db->opt_txn_db->GetBaseDB();
       }
     } else if (FLAGS_transaction_db) {
-      TransactionDB* ptr;
+      TransactionDB* ptr = nullptr;
       TransactionDBOptions txn_db_options;
       s = CreateLoggerFromOptions(db_name, options, &options.info_log);
       if (s.ok()) {
@@ -3376,7 +3376,7 @@ void VerifyDBFromDB(std::string& truth_db_name) {
       }
     } else if (FLAGS_use_blob_db) {
       blob_db::BlobDBOptions blob_db_options;
-      blob_db::BlobDB* ptr;
+      blob_db::BlobDB* ptr = nullptr;
       s = blob_db::BlobDB::Open(options, blob_db_options, db_name, &ptr);
       if (s.ok()) {
         db->db = ptr;

tools/ldb_cmd.cc

@@ -2806,7 +2806,7 @@ void DumpSstFile(std::string filename, bool output_hex, bool show_properties) {
   }
   // no verification
   rocksdb::SstFileReader reader(filename, false, output_hex);
-  Status st = reader.ReadSequential(true, -1, false,  // has_from
+  Status st = reader.ReadSequential(true, std::numeric_limits<uint64_t>::max(), false,  // has_from
                                     from_key, false,  // has_to
                                     to_key);
   if (!st.ok()) {

tools/sst_dump_tool.cc

@@ -81,7 +81,7 @@ Status SstFileReader::GetTableReader(const std::string& file_path) {
   Footer footer;
 
   unique_ptr<RandomAccessFile> file;
-  uint64_t file_size;
+  uint64_t file_size = 0;
   Status s = options_.env->NewRandomAccessFile(file_path, &file, soptions_);
   if (s.ok()) {
     s = options_.env->GetFileSize(file_path, &file_size);
@@ -411,7 +411,7 @@ void print_help() {
 
 int SSTDumpTool::Run(int argc, char** argv) {
   const char* dir_or_file = nullptr;
-  uint64_t read_num = -1;
+  uint64_t read_num = std::numeric_limits<uint64_t>::max();
   std::string command;
 
   char junk;
@@ -428,7 +428,7 @@ int SSTDumpTool::Run(int argc, char** argv) {
   std::string from_key;
   std::string to_key;
   std::string block_size_str;
-  size_t block_size;
+  size_t block_size = 0;
   std::vector<std::pair<CompressionType, const char*>> compression_types;
   uint64_t total_num_files = 0;
   uint64_t total_num_data_blocks = 0;

tools/write_stress.cc

@@ -163,7 +163,7 @@ class WriteStress {
       std::uniform_int_distribution<int> char_dist('a', 'z');
       std::string ret;
       for (int i = 0; i < len; ++i) {
-        ret += char_dist(r);
+        ret += static_cast<char>(char_dist(r));
       }
       return ret;
     };
@@ -210,13 +210,13 @@ class WriteStress {
                                            FLAGS_prefix_mutate_period_sec *
                                            1000 * 1000LL));
       if (dist(rng) < FLAGS_first_char_mutate_probability) {
-        key_prefix_[0].store(char_dist(rng), std::memory_order_relaxed);
+        key_prefix_[0].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
       }
       if (dist(rng) < FLAGS_second_char_mutate_probability) {
-        key_prefix_[1].store(char_dist(rng), std::memory_order_relaxed);
+        key_prefix_[1].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
       }
       if (dist(rng) < FLAGS_third_char_mutate_probability) {
-        key_prefix_[2].store(char_dist(rng), std::memory_order_relaxed);
+        key_prefix_[2].store(static_cast<char>(char_dist(rng)), std::memory_order_relaxed);
       }
     }
   }

util/coding.cc

@@ -15,6 +15,11 @@
 
 namespace rocksdb {
 
+// conversion' conversion from 'type1' to 'type2', possible loss of data
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4244)
+#endif
 char* EncodeVarint32(char* dst, uint32_t v) {
   // Operate on characters as unsigneds
   unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
@@ -42,6 +47,9 @@ char* EncodeVarint32(char* dst, uint32_t v) {
   }
   return reinterpret_cast<char*>(ptr);
 }
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
 const char* GetVarint32PtrFallback(const char* p, const char* limit,
                                    uint32_t* value) {

util/compression.h

@@ -46,8 +46,9 @@ namespace rocksdb {
 inline bool Snappy_Supported() {
 #ifdef SNAPPY
   return true;
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool Zlib_Supported() {
@@ -60,37 +61,42 @@ inline bool Zlib_Supported() {
 inline bool BZip2_Supported() {
 #ifdef BZIP2
   return true;
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool LZ4_Supported() {
 #ifdef LZ4
   return true;
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool XPRESS_Supported() {
 #ifdef XPRESS
   return true;
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool ZSTD_Supported() {
 #ifdef ZSTD
   // ZSTD format is finalized since version 0.8.0.
   return (ZSTD_versionNumber() >= 800);
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool ZSTDNotFinal_Supported() {
 #ifdef ZSTD
   return true;
-#endif
+#else
   return false;
+#endif
 }
 
 inline bool CompressionTypeSupported(CompressionType compression_type) {
@@ -159,9 +165,9 @@ inline bool Snappy_Compress(const CompressionOptions& opts, const char* input,
   snappy::RawCompress(input, length, &(*output)[0], &outlen);
   output->resize(outlen);
   return true;
-#endif
+#else
-
   return false;
+#endif
 }
 
 inline bool Snappy_GetUncompressedLength(const char* input, size_t length,
@@ -708,16 +714,18 @@ inline bool LZ4HC_Compress(const CompressionOptions& opts,
 inline bool XPRESS_Compress(const char* input, size_t length, std::string* output) {
 #ifdef XPRESS
   return port::xpress::Compress(input, length, output);
-#endif
+#else
   return false;
+#endif
 }
 
 inline char* XPRESS_Uncompress(const char* input_data, size_t input_length,
   int* decompress_size) {
 #ifdef XPRESS
   return port::xpress::Decompress(input_data, input_length, decompress_size);
-#endif
+#else
   return nullptr;
+#endif
 }
 
 

util/crc32c_test.cc

@@ -26,12 +26,12 @@ TEST(CRC, StandardResults) {
   ASSERT_EQ(0x62a8ab43U, Value(buf, sizeof(buf)));
 
   for (int i = 0; i < 32; i++) {
-    buf[i] = i;
+    buf[i] = static_cast<char>(i);
   }
   ASSERT_EQ(0x46dd794eU, Value(buf, sizeof(buf)));
 
   for (int i = 0; i < 32; i++) {
-    buf[i] = 31 - i;
+    buf[i] = static_cast<char>(31 - i);
   }
   ASSERT_EQ(0x113fdb5cU, Value(buf, sizeof(buf)));
 

util/dynamic_bloom.h

@@ -125,12 +125,20 @@ inline bool DynamicBloom::MayContain(const Slice& key) const {
   return (MayContainHash(hash_func_(key)));
 }
 
+#if defined(_MSC_VER)
+#pragma warning(push)
+// local variable is initialized but not referenced
+#pragma warning(disable : 4189) 
+#endif
 inline void DynamicBloom::Prefetch(uint32_t h) {
   if (kNumBlocks != 0) {
     uint32_t b = ((h >> 11 | (h << 21)) % kNumBlocks) * (CACHE_LINE_SIZE * 8);
     PREFETCH(&(data_[b / 8]), 0, 3);
   }
 }
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
 inline bool DynamicBloom::MayContainHash(uint32_t h) const {
   assert(IsInitialized());

util/slice.cc

@@ -182,7 +182,7 @@ bool Slice::DecodeHex(std::string* result) const {
     if (h2 < 0) {
       return false;
     }
-    result->push_back((h1 << 4) | h2);
+    result->push_back(static_cast<char>((h1 << 4) | h2));
   }
   return true;
 }

util/thread_local.cc

@@ -174,7 +174,7 @@ namespace wintlscleanup {
 
 // This is set to OnThreadExit in StaticMeta singleton constructor
 UnrefHandler thread_local_inclass_routine = nullptr;
-pthread_key_t thread_local_key = -1;
+pthread_key_t thread_local_key = pthread_key_t (-1);
 
 // Static callback function to call with each thread termination.
 void NTAPI WinOnThreadExit(PVOID module, DWORD reason, PVOID reserved) {

utilities/blob_db/blob_log_writer.cc

@@ -87,7 +87,7 @@ Status Writer::AddRecord(const Slice& key, const Slice& val,
   assert(last_elem_type_ == kEtFileHdr || last_elem_type_ == kEtRecord);
 
   std::string buf;
-  ConstructBlobHeader(&buf, key, val, -1, -1);
+  ConstructBlobHeader(&buf, key, val, 0, -1);
 
   Status s = EmitPhysicalRecord(buf, key, val, key_offset, blob_offset);
   return s;

utilities/document/document_db.cc

@@ -431,6 +431,10 @@ class SimpleSortedIndex : public Index {
     return direction;
   }
   // REQUIRES: UsefulIndex(filter) == true
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4702) // Unreachable code
+#endif
   virtual bool ShouldContinueLooking(
       const Filter& filter, const Slice& secondary_key,
       Index::Direction direction) const override {
@@ -483,7 +487,9 @@ class SimpleSortedIndex : public Index {
     // this is here just so compiler doesn't complain
     return false;
   }
-
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
  private:
   std::string field_;
   std::string name_;
@@ -1060,6 +1066,10 @@ class DocumentDBImpl : public DocumentDB {
   }
 
  private:
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4702) // unreachable code
+#endif
   Cursor* ConstructFilterCursor(ReadOptions read_options, Cursor* cursor,
                                 const JSONDocument& query) {
     std::unique_ptr<const Filter> filter(Filter::ParseFilter(query));
@@ -1113,6 +1123,9 @@ class DocumentDBImpl : public DocumentDB {
     assert(false);
     return nullptr;
   }
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
   // currently, we lock and serialize all writes to rocksdb. reads are not
   // locked and always get consistent view of the database. we should optimize

utilities/persistent_cache/hash_table_evictable.h

@@ -88,7 +88,7 @@ class EvictableHashTable : private HashTable<T*, Hash, Equal> {
 
       WriteLock _(&hash_table::locks_[idx]);
       LRUListType& lru = lru_lists_[idx];
-      if (!lru.IsEmpty() && (t = lru.Pop())) {
+      if (!lru.IsEmpty() && (t = lru.Pop()) != nullptr) {
         assert(!t->refs_);
         // We got an item to evict, erase from the bucket
         const uint64_t h = Hash()(t);

utilities/redis/redis_lists_test.cc

@@ -747,7 +747,7 @@ namespace {
 void MakeUpper(std::string* const s) {
   int len = static_cast<int>(s->length());
   for (int i = 0; i < len; ++i) {
-    (*s)[i] = toupper((*s)[i]);  // C-version defined in <ctype.h>
+    (*s)[i] = static_cast<char>(toupper((*s)[i]));  // C-version defined in <ctype.h>
   }
 }
 

utilities/spatialdb/spatial_db_test.cc

@@ -224,7 +224,7 @@ namespace {
 std::string RandomStr(Random* rnd) {
   std::string r;
   for (int k = 0; k < 10; ++k) {
-    r.push_back(rnd->Uniform(26) + 'a');
+    r.push_back(static_cast<char>(rnd->Uniform(26)) + 'a');
   }
   return r;
 }

utilities/transactions/transaction_test.cc

@@ -1153,11 +1153,11 @@ TEST_P(TransactionTest, DISABLED_TwoPhaseMultiThreadTest) {
     if (id % 2 == 0) {
       txn_options.expiration = 1000000;
     }
-    TransactionName name("xid_" + std::string(1, 'A' + id));
+    TransactionName name("xid_" + std::string(1, 'A' + static_cast<char>(id)));
     Transaction* txn = db->BeginTransaction(write_options, txn_options);
     ASSERT_OK(txn->SetName(name));
     for (int i = 0; i < 10; i++) {
-      std::string key(name + "_" + std::string(1, 'A' + i));
+      std::string key(name + "_" + std::string(1, static_cast<char>('A' + i)));
       ASSERT_OK(txn->Put(key, "val"));
     }
     ASSERT_OK(txn->Prepare());
@@ -1208,9 +1208,9 @@ TEST_P(TransactionTest, DISABLED_TwoPhaseMultiThreadTest) {
   std::string value;
   Status s;
   for (uint32_t t = 0; t < NUM_TXN_THREADS; t++) {
-    TransactionName name("xid_" + std::string(1, 'A' + t));
+    TransactionName name("xid_" + std::string(1, 'A' + static_cast<char>(t)));
     for (int i = 0; i < 10; i++) {
-      std::string key(name + "_" + std::string(1, 'A' + i));
+      std::string key(name + "_" + std::string(1, static_cast<char>('A' + i)));
       s = db->Get(read_options, key, &value);
       ASSERT_OK(s);
       ASSERT_EQ(value, "val");