backport https://github.com/google/mozc/commit/7118076.patch
Burn down unsafe `reinterpret_cast`s.
--- a/config/BUILD.bazel
+++ b/config/BUILD.bazel
@@ -137,6 +137,7 @@ mozc_cc_test(
             "//protocol:config_cc_proto",
         ],
         windows = [
+            "//base:bits",
             "//base/win32:win_api_test_helper",
             "@com_google_absl//absl/base",
             "@com_google_absl//absl/container:flat_hash_map",
@@ -164,6 +165,7 @@ mozc_cc_library(
     ],
     deps = [
         ":config_handler",
+        "//base:bits",
         "//base:config_file_stream",
         "//base:number_util",
         "//base:singleton",
--- a/config/character_form_manager.cc
+++ b/config/character_form_manager.cc
@@ -44,6 +44,7 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "absl/types/span.h"
+#include "base/bits.h"
 #include "base/config_file_stream.h"
 #include "base/number_util.h"
 #include "base/singleton.h"
@@ -379,7 +380,7 @@ Config::CharacterForm CharacterFormManagerImpl::GetCharacterFormFromStorage(
   if (value == nullptr) {
     return Config::FULL_WIDTH;  // Return default setting
   }
-  const uint32_t ivalue = *reinterpret_cast<const uint32_t*>(value);
+  const uint32_t ivalue = LoadUnaligned<uint32_t>(value);
   return static_cast<Config::CharacterForm>(ivalue);
 }
 
--- a/config/stats_config_util_test.cc
+++ b/config/stats_config_util_test.cc
@@ -42,6 +42,7 @@
 #include <bit>
 
 #include "absl/container/flat_hash_map.h"
+#include "base/bits.h"
 #include "base/singleton.h"
 #include "base/win32/win_api_test_helper.h"
 #endif  // _WIN32
@@ -228,7 +229,7 @@ class RegistryEmulator {
     if (!CheckWritable(key)) {
       return ERROR_ACCESS_DENIED;
     }
-    SetUsagestatsValue(key, *reinterpret_cast<const DWORD*>(data));
+    SetUsagestatsValue(key, LoadUnaligned<DWORD>(data));
     return ERROR_SUCCESS;
   }
   static LSTATUS WINAPI TestRegCloseKey(HKEY key) { return ERROR_SUCCESS; }
--- a/converter/BUILD.bazel
+++ b/converter/BUILD.bazel
@@ -222,6 +222,7 @@ mozc_cc_library(
         "//prediction:__pkg__",
     ],
     deps = [
+        "//base:bits",
         "//data_manager",
         "//storage/louds:simple_succinct_bit_vector_index",
         "@com_google_absl//absl/status",
@@ -241,6 +242,7 @@ mozc_cc_test(
     ],
     deps = [
         ":connector",
+        "//base:bits",
         "//base:mmap",
         "//base:vlog",
         "//data_manager:connection_file_reader",
--- a/converter/connector.cc
+++ b/converter/connector.cc
@@ -45,6 +45,7 @@
 #include "absl/strings/escaping.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
+#include "base/bits.h"
 #include "data_manager/data_manager.h"
 #include "storage/louds/simple_succinct_bit_vector_index.h"
 
@@ -245,11 +246,11 @@ absl::Status Connector::Init(absl::string_view connection_data) {
     // |ptr| points to here now.  Every uint8_t[] block needs to be aligned at
     // 32-bit boundary.
     VALIDATE_SIZE(ptr, 2, "Compact bits size of row ", i, "/", rsize);
-    const uint16_t compact_bits_size = *reinterpret_cast<const uint16_t*>(ptr);
+    const uint16_t compact_bits_size = LoadUnaligned<uint16_t>(ptr);
     ptr += 2;
 
     VALIDATE_SIZE(ptr, 2, "Values size of row ", i, "/", rsize);
-    const uint16_t values_size = *reinterpret_cast<const uint16_t*>(ptr);
+    const uint16_t values_size = LoadUnaligned<uint16_t>(ptr);
     ptr += 2;
 
     VALIDATE_SIZE(ptr, chunk_bits_size, "Chunk bits of row ", i, "/", rsize);
--- a/converter/connector_test.cc
+++ b/converter/connector_test.cc
@@ -39,6 +39,7 @@
 #include "absl/random/random.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
+#include "base/bits.h"
 #include "base/mmap.h"
 #include "base/vlog.h"
 #include "data_manager/connection_file_reader.h"
@@ -102,7 +103,7 @@ TEST(ConnectorTest, BrokenData) {
   // Invalid magic number.
   {
     data.assign(cmmap->begin(), cmmap->size());
-    *reinterpret_cast<uint16_t*>(&data[0]) = 0;
+    StoreUnaligned<uint16_t>(0, &data[0]);
     const auto status = Connector::Create(data).status();
     MOZC_VLOG(1) << status;
     EXPECT_FALSE(status.ok());
--- a/converter/inner_segment.h
+++ b/converter/inner_segment.h
@@ -31,6 +31,7 @@
 #define MOZC_CONVERTER_INNER_SEGMENT_H_
 
 #include <algorithm>
+#include <bit>
 #include <cstddef>
 #include <cstdint>
 #include <iterator>
@@ -94,11 +95,11 @@ inline std::optional<uint32_t> EncodeLengths(uint32_t key_len,
 
   const internal::LengthData data{key_len, value_len, content_key_len,
                                   content_value_len};
-  return *reinterpret_cast<const uint32_t*>(&data);
+  return std::bit_cast<uint32_t>(data);
 }
 
 inline internal::LengthData DecodeLengths(uint32_t encoded) {
-  return *reinterpret_cast<const struct internal::LengthData*>(&encoded);
+  return std::bit_cast<internal::LengthData>(encoded);
 }
 
 // Iterator class to access inner segments.
--- a/data_manager/BUILD.bazel
+++ b/data_manager/BUILD.bazel
@@ -317,4 +317,5 @@ mozc_cc_library(
     name = "emoji_data",
     hdrs = ["emoji_data.h"],
     visibility = ["//rewriter:__pkg__"],
+    deps = ["//base:bits"],
 )
--- a/data_manager/emoji_data.h
+++ b/data_manager/emoji_data.h
@@ -35,6 +35,8 @@
 #include <iterator>
 #include <utility>
 
+#include "base/bits.h"
+
 namespace mozc {
 
 // Emoji Version Data, in Unicode.
@@ -99,17 +101,13 @@ class EmojiDataIterator {
   EmojiDataIterator() : ptr_(nullptr) {}
   explicit EmojiDataIterator(const char* ptr) : ptr_(ptr) {}
 
-  uint32_t key_index() const {
-    return *reinterpret_cast<const uint32_t*>(ptr_);
-  }
-  uint32_t emoji_index() const {
-    return *reinterpret_cast<const uint32_t*>(ptr_ + 4);
-  }
+  uint32_t key_index() const { return LoadUnaligned<uint32_t>(ptr_); }
+  uint32_t emoji_index() const { return LoadUnaligned<uint32_t>(ptr_ + 4); }
   uint32_t unicode_version_index() const {
-    return *reinterpret_cast<const uint32_t*>(ptr_ + 8);
+    return LoadUnaligned<uint32_t>(ptr_ + 8);
   }
   uint32_t description_utf8_index() const {
-    return *reinterpret_cast<const uint32_t*>(ptr_ + 12);
+    return LoadUnaligned<uint32_t>(ptr_ + 12);
   }
 
   // Returns key index as token array is searched by key.
--- a/data_manager/serialized_dictionary.h
+++ b/data_manager/serialized_dictionary.h
@@ -42,6 +42,7 @@
 
 #include "absl/log/check.h"
 #include "absl/strings/string_view.h"
+#include "base/bits.h"
 #include "base/container/serialized_string_array.h"
 
 namespace mozc {
@@ -137,72 +138,35 @@ class SerializedDictionary {
         : token_ptr_(token_ptr), string_array_(string_array) {}
     iterator(const iterator& x) = default;
 
-    uint32_t key_index() {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_);
-    }
-    uint32_t key_index() const {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_);
-    }
-    absl::string_view key() { return (*string_array_)[key_index()]; }
+    uint32_t key_index() const { return LoadUnaligned<uint32_t>(token_ptr_); }
     absl::string_view key() const { return (*string_array_)[key_index()]; }
 
-    uint32_t value_index() {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 4);
-    }
     uint32_t value_index() const {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 4);
+      return LoadUnaligned<uint32_t>(token_ptr_ + 4);
     }
-    absl::string_view value() { return (*string_array_)[value_index()]; }
     absl::string_view value() const { return (*string_array_)[value_index()]; }
 
-    uint32_t description_index() {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 8);
-    }
     uint32_t description_index() const {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 8);
+      return LoadUnaligned<uint32_t>(token_ptr_ + 8);
     }
 
-    absl::string_view description() {
-      return (*string_array_)[description_index()];
-    }
     absl::string_view description() const {
       return (*string_array_)[description_index()];
     }
 
-    uint32_t additional_description_index() {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 12);
-    }
     uint32_t additional_description_index() const {
-      return *reinterpret_cast<const uint32_t*>(token_ptr_ + 12);
-    }
-    absl::string_view additional_description() {
-      return (*string_array_)[additional_description_index()];
+      return LoadUnaligned<uint32_t>(token_ptr_ + 12);
     }
 
     absl::string_view additional_description() const {
       return (*string_array_)[additional_description_index()];
     }
 
-    uint16_t lid() {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 16);
-    }
-    uint16_t lid() const {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 16);
-    }
+    uint16_t lid() const { return LoadUnaligned<uint16_t>(token_ptr_ + 16); }
 
-    uint16_t rid() {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 18);
-    }
-    uint16_t rid() const {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 18);
-    }
+    uint16_t rid() const { return LoadUnaligned<uint16_t>(token_ptr_ + 18); }
 
-    int16_t cost() {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 20);
-    }
-    int16_t cost() const {
-      return *reinterpret_cast<const uint16_t*>(token_ptr_ + 20);
-    }
+    int16_t cost() const { return LoadUnaligned<int16_t>(token_ptr_ + 20); }
 
     absl::string_view operator*() { return key(); }
     absl::string_view operator*() const { return key(); }
--- a/dictionary/BUILD.bazel
+++ b/dictionary/BUILD.bazel
@@ -546,6 +546,7 @@ mozc_cc_library(
         "//rewriter:__pkg__",
     ],
     deps = [
+        "//base:bits",
         "//base/container:serialized_string_array",
         "//base/strings:assign",
         "//data_manager",
--- a/dictionary/user_pos.h
+++ b/dictionary/user_pos.h
@@ -40,6 +40,7 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
+#include "base/bits.h"
 #include "base/container/serialized_string_array.h"
 #include "data_manager/data_manager.h"
 
@@ -132,17 +133,15 @@ class UserPos {
     explicit iterator(const char* ptr) : ptr_(ptr) {}
     iterator(const iterator& x) = default;
 
-    uint16_t pos_index() const {
-      return *reinterpret_cast<const uint16_t*>(ptr_);
-    }
+    uint16_t pos_index() const { return LoadUnaligned<uint16_t>(ptr_); }
     uint16_t value_suffix_index() const {
-      return *reinterpret_cast<const uint16_t*>(ptr_ + 2);
+      return LoadUnaligned<uint16_t>(ptr_ + 2);
     }
     uint16_t key_suffix_index() const {
-      return *reinterpret_cast<const uint16_t*>(ptr_ + 4);
+      return LoadUnaligned<uint16_t>(ptr_ + 4);
     }
     uint16_t conjugation_id() const {
-      return *reinterpret_cast<const uint16_t*>(ptr_ + 6);
+      return LoadUnaligned<uint16_t>(ptr_ + 6);
     }
 
     uint16_t operator*() const { return pos_index(); }
--- a/prediction/BUILD.bazel
+++ b/prediction/BUILD.bazel
@@ -512,6 +512,7 @@ mozc_cc_library(
         "//engine:__pkg__",
     ],
     deps = [
+        "//base:bits",
         "//base/container:serialized_string_array",
         "@com_google_absl//absl/strings",
     ],
--- a/prediction/zero_query_dict.h
+++ b/prediction/zero_query_dict.h
@@ -37,6 +37,7 @@
 #include <utility>
 
 #include "absl/strings/string_view.h"
+#include "base/bits.h"
 #include "base/container/serialized_string_array.h"
 
 namespace mozc {
@@ -98,21 +99,17 @@ class ZeroQueryDict {
     uint32_t operator*() const { return key_index(); }
 
     uint32_t operator[](ptrdiff_t n) const {
-      return *reinterpret_cast<const uint32_t*>(ptr_ + n * kTokenByteSize);
+      return LoadUnaligned<uint32_t>(ptr_ + n * kTokenByteSize);
     }
 
     const iterator* operator->() const { return this; }
 
-    uint32_t key_index() const {
-      return *reinterpret_cast<const uint32_t*>(ptr_);
-    }
+    uint32_t key_index() const { return LoadUnaligned<uint32_t>(ptr_); }
 
-    uint32_t value_index() const {
-      return *reinterpret_cast<const uint32_t*>(ptr_ + 4);
-    }
+    uint32_t value_index() const { return LoadUnaligned<uint32_t>(ptr_ + 4); }
 
     ZeroQueryType type() const {
-      const uint16_t val = *reinterpret_cast<const uint16_t*>(ptr_ + 8);
+      const uint16_t val = LoadUnaligned<uint16_t>(ptr_ + 8);
       return static_cast<ZeroQueryType>(val);
     }