Merge tag 'refs/tags/sync-piper' into sync-stage

conformance/conformance_cpp.cc

@@ -36,6 +36,7 @@
 #include <google/protobuf/text_format.h>
 #include <google/protobuf/util/json_util.h>
 #include <google/protobuf/util/type_resolver_util.h>
+#include <google/protobuf/stubs/status.h>
 #include "conformance.pb.h"
 #include <google/protobuf/test_messages_proto2.pb.h>
 #include <google/protobuf/test_messages_proto3.pb.h>
@@ -125,9 +126,9 @@ void DoTest(const ConformanceRequest& request, ConformanceResponse* response) {
       options.ignore_unknown_fields =
           (request.test_category() ==
               conformance::JSON_IGNORE_UNKNOWN_PARSING_TEST);
-      Status status = JsonToBinaryString(type_resolver, *type_url,
-                                         request.json_payload(), &proto_binary,
-                                         options);
+      util::Status status =
+          JsonToBinaryString(type_resolver, *type_url, request.json_payload(),
+                             &proto_binary, options);
       if (!status.ok()) {
         response->set_parse_error(string("Parse error: ") +
                                   std::string(status.error_message()));
@@ -179,8 +180,9 @@ void DoTest(const ConformanceRequest& request, ConformanceResponse* response) {
     case conformance::JSON: {
       string proto_binary;
       GOOGLE_CHECK(test_message->SerializeToString(&proto_binary));
-      Status status = BinaryToJsonString(type_resolver, *type_url, proto_binary,
-                                         response->mutable_json_payload());
+      util::Status status =
+          BinaryToJsonString(type_resolver, *type_url, proto_binary,
+                             response->mutable_json_payload());
       if (!status.ok()) {
         response->set_serialize_error(
             string("Failed to serialize JSON output: ") +

java/core/src/main/java/com/google/protobuf/FieldSet.java

@@ -119,7 +119,6 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
   }
 
   /** Make this FieldSet immutable from this point forward. */
-  @SuppressWarnings("unchecked")
   public void makeImmutable() {
     if (isImmutable) {
       return;
@@ -286,11 +285,11 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
       final List newList = new ArrayList();
       newList.addAll((List) value);
       for (final Object element : newList) {
-        verifyType(descriptor.getLiteType(), element);
+        verifyType(descriptor, element);
       }
       value = newList;
     } else {
-      verifyType(descriptor.getLiteType(), value);
+      verifyType(descriptor, value);
     }
 
     if (value instanceof LazyField) {
@@ -354,7 +353,7 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
       throw new IndexOutOfBoundsException();
     }
 
-    verifyType(descriptor.getLiteType(), value);
+    verifyType(descriptor, value);
     ((List<Object>) list).set(index, value);
   }
 
@@ -369,7 +368,7 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
           "addRepeatedField() can only be called on repeated fields.");
     }
 
-    verifyType(descriptor.getLiteType(), value);
+    verifyType(descriptor, value);
 
     final Object existingValue = getField(descriptor);
     List<Object> list;
@@ -390,8 +389,8 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
    *
    * @throws IllegalArgumentException The value is not of the right type.
    */
-  private void verifyType(final WireFormat.FieldType type, final Object value) {
-    if (!isValidType(type, value)) {
+  private void verifyType(final T descriptor, final Object value) {
+    if (!isValidType(descriptor.getLiteType(), value)) {
       // TODO(kenton):  When chaining calls to setField(), it can be hard to
       //   tell from the stack trace which exact call failed, since the whole
       //   chain is considered one line of code.  It would be nice to print
@@ -400,10 +399,16 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
       //   isn't a big deal, though, since it would only really apply when using
       //   reflection and generally people don't chain reflection setters.
       throw new IllegalArgumentException(
-          "Wrong object type used with protocol message reflection.");
+          String.format(
+              "Wrong object type used with protocol message reflection.\n"
+              + "Field number: %d, field java type: %s, value type: %s\n",
+              descriptor.getNumber(),
+              descriptor.getLiteType().getJavaType(),
+              value.getClass().getName()));
     }
   }
 
+
   private static boolean isValidType(final WireFormat.FieldType type, final Object value) {
     checkNotNull(value);
     switch (type.getJavaType()) {
@@ -1081,12 +1086,12 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
         final List newList = new ArrayList();
         newList.addAll((List) value);
         for (final Object element : newList) {
-          verifyType(descriptor.getLiteType(), element);
+          verifyType(descriptor, element);
           hasNestedBuilders = hasNestedBuilders || element instanceof MessageLite.Builder;
         }
         value = newList;
       } else {
-        verifyType(descriptor.getLiteType(), value);
+        verifyType(descriptor, value);
       }
 
       if (value instanceof LazyField) {
@@ -1172,7 +1177,7 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
         throw new IndexOutOfBoundsException();
       }
 
-      verifyType(descriptor.getLiteType(), value);
+      verifyType(descriptor, value);
       ((List<Object>) list).set(index, value);
     }
 
@@ -1190,7 +1195,7 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
 
       hasNestedBuilders = hasNestedBuilders || value instanceof MessageLite.Builder;
 
-      verifyType(descriptor.getLiteType(), value);
+      verifyType(descriptor, value);
 
       final Object existingValue = getField(descriptor);
       List<Object> list;
@@ -1211,15 +1216,20 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
      *
      * @throws IllegalArgumentException The value is not of the right type.
      */
-    private static void verifyType(final WireFormat.FieldType type, final Object value) {
-      if (!FieldSet.isValidType(type, value)) {
+    private void verifyType(final T descriptor, final Object value) {
+      if (!FieldSet.isValidType(descriptor.getLiteType(), value)) {
         // Builder can accept Message.Builder values even though FieldSet will reject.
-        if (type.getJavaType() == WireFormat.JavaType.MESSAGE
+        if (descriptor.getLiteType().getJavaType() == WireFormat.JavaType.MESSAGE
             && value instanceof MessageLite.Builder) {
           return;
         }
         throw new IllegalArgumentException(
-            "Wrong object type used with protocol message reflection.");
+            String.format(
+                "Wrong object type used with protocol message reflection.\n"
+                + "Field number: %d, field java type: %s, value type: %s\n",
+                descriptor.getNumber(),
+                descriptor.getLiteType().getJavaType(),
+                value.getClass().getName()));
       }
     }
 

java/core/src/main/java/com/google/protobuf/TextFormat.java

@@ -61,6 +61,7 @@ public final class TextFormat {
 
   private static final Logger logger = Logger.getLogger(TextFormat.class.getName());
 
+
   /**
    * Outputs a textual representation of the Protocol Message supplied into the parameter output.
    * (This representation is the new version of the classic "ProtocolPrinter" output from the
@@ -727,9 +728,9 @@ public final class TextFormat {
           // Groups must be serialized with their original capitalization.
           generator.print(field.getMessageType().getName());
         } else {
-          generator.print(field.getName());
+            generator.print(field.getName());
+          }
         }
-      }
 
       if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
         generator.print(" {");
@@ -1811,16 +1812,16 @@ public final class TextFormat {
         extension = target.findExtensionByName(extensionRegistry, name.toString());
 
         if (extension == null) {
-          String message =
-              (tokenizer.getPreviousLine() + 1)
-                  + ":"
-                  + (tokenizer.getPreviousColumn() + 1)
-                  + ":\t"
-                  + type.getFullName()
-                  + ".["
-                  + name
-                  + "]";
-          unknownFields.add(new UnknownField(message, UnknownField.Type.EXTENSION));
+            String message =
+                (tokenizer.getPreviousLine() + 1)
+                    + ":"
+                    + (tokenizer.getPreviousColumn() + 1)
+                    + ":\t"
+                    + type.getFullName()
+                    + ".["
+                    + name
+                    + "]";
+            unknownFields.add(new UnknownField(message, UnknownField.Type.EXTENSION));
         } else {
           if (extension.descriptor.getContainingType() != type) {
             throw tokenizer.parseExceptionPreviousToken(

java/core/src/main/java/com/google/protobuf/UnsafeUtil.java

@@ -388,7 +388,7 @@ final class UnsafeUtil {
       }
 
       if (Android.isOnAndroidDevice()) {
-        return true;
+        return false;
       }
       clazz.getMethod("getByte", long.class);
       clazz.getMethod("putByte", long.class, byte.class);

java/core/src/test/java/com/google/protobuf/MapForProto2LiteTest.java

@@ -184,17 +184,17 @@ public final class MapForProto2LiteTest extends TestCase {
   }
 
   private void assertMapValuesCleared(TestMapOrBuilder testMapOrBuilder) {
-    assertEquals(0, testMapOrBuilder.getInt32ToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToStringField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToStringFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToStringFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToBytesField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToEnumField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToMessageField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldCount());
-    assertEquals(0, testMapOrBuilder.getStringToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getStringToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getStringToInt32FieldCount());
   }
 
@@ -226,13 +226,13 @@ public final class MapForProto2LiteTest extends TestCase {
   }
 
   private void assertMapsAreImmutable(TestMapOrBuilder testMapOrBuilder) {
-    assertImmutable(testMapOrBuilder.getInt32ToInt32Field(), 1, 2);
-    assertImmutable(testMapOrBuilder.getInt32ToStringField(), 1, "2");
-    assertImmutable(testMapOrBuilder.getInt32ToBytesField(), 1, TestUtil.toBytes("2"));
-    assertImmutable(testMapOrBuilder.getInt32ToEnumField(), 1, TestMap.EnumValue.FOO);
+    assertImmutable(testMapOrBuilder.getInt32ToInt32FieldMap(), 1, 2);
+    assertImmutable(testMapOrBuilder.getInt32ToStringFieldMap(), 1, "2");
+    assertImmutable(testMapOrBuilder.getInt32ToBytesFieldMap(), 1, TestUtil.toBytes("2"));
+    assertImmutable(testMapOrBuilder.getInt32ToEnumFieldMap(), 1, TestMap.EnumValue.FOO);
     assertImmutable(
-        testMapOrBuilder.getInt32ToMessageField(), 1, MessageValue.getDefaultInstance());
-    assertImmutable(testMapOrBuilder.getStringToInt32Field(), "1", 2);
+        testMapOrBuilder.getInt32ToMessageFieldMap(), 1, MessageValue.getDefaultInstance());
+    assertImmutable(testMapOrBuilder.getStringToInt32FieldMap(), "1", 2);
   }
 
   private <K, V> void assertImmutable(Map<K, V> map, K key, V value) {

java/core/src/test/java/com/google/protobuf/MapForProto2Test.java

@@ -128,35 +128,35 @@ public class MapForProto2Test extends TestCase {
   }
 
   private void assertMapValuesSet(TestMapOrBuilder message) {
-    assertEquals(3, message.getInt32ToInt32Field().size());
-    assertEquals(11, message.getInt32ToInt32Field().get(1).intValue());
-    assertEquals(22, message.getInt32ToInt32Field().get(2).intValue());
-    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
-
-    assertEquals(3, message.getInt32ToStringField().size());
-    assertEquals("11", message.getInt32ToStringField().get(1));
-    assertEquals("22", message.getInt32ToStringField().get(2));
-    assertEquals("33", message.getInt32ToStringField().get(3));
-
-    assertEquals(3, message.getInt32ToBytesField().size());
-    assertEquals(TestUtil.toBytes("11"), message.getInt32ToBytesField().get(1));
-    assertEquals(TestUtil.toBytes("22"), message.getInt32ToBytesField().get(2));
-    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
-
-    assertEquals(3, message.getInt32ToEnumField().size());
-    assertEquals(TestMap.EnumValue.FOO, message.getInt32ToEnumField().get(1));
-    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(2));
-    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
-
-    assertEquals(3, message.getInt32ToMessageField().size());
-    assertEquals(11, message.getInt32ToMessageField().get(1).getValue());
-    assertEquals(22, message.getInt32ToMessageField().get(2).getValue());
-    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
-
-    assertEquals(3, message.getStringToInt32Field().size());
-    assertEquals(11, message.getStringToInt32Field().get("1").intValue());
-    assertEquals(22, message.getStringToInt32Field().get("2").intValue());
-    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+    assertEquals(3, message.getInt32ToInt32FieldMap().size());
+    assertEquals(11, message.getInt32ToInt32FieldMap().get(1).intValue());
+    assertEquals(22, message.getInt32ToInt32FieldMap().get(2).intValue());
+    assertEquals(33, message.getInt32ToInt32FieldMap().get(3).intValue());
+
+    assertEquals(3, message.getInt32ToStringFieldMap().size());
+    assertEquals("11", message.getInt32ToStringFieldMap().get(1));
+    assertEquals("22", message.getInt32ToStringFieldMap().get(2));
+    assertEquals("33", message.getInt32ToStringFieldMap().get(3));
+
+    assertEquals(3, message.getInt32ToBytesFieldMap().size());
+    assertEquals(TestUtil.toBytes("11"), message.getInt32ToBytesFieldMap().get(1));
+    assertEquals(TestUtil.toBytes("22"), message.getInt32ToBytesFieldMap().get(2));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesFieldMap().get(3));
+
+    assertEquals(3, message.getInt32ToEnumFieldMap().size());
+    assertEquals(TestMap.EnumValue.FOO, message.getInt32ToEnumFieldMap().get(1));
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumFieldMap().get(2));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumFieldMap().get(3));
+
+    assertEquals(3, message.getInt32ToMessageFieldMap().size());
+    assertEquals(11, message.getInt32ToMessageFieldMap().get(1).getValue());
+    assertEquals(22, message.getInt32ToMessageFieldMap().get(2).getValue());
+    assertEquals(33, message.getInt32ToMessageFieldMap().get(3).getValue());
+
+    assertEquals(3, message.getStringToInt32FieldMap().size());
+    assertEquals(11, message.getStringToInt32FieldMap().get("1").intValue());
+    assertEquals(22, message.getStringToInt32FieldMap().get("2").intValue());
+    assertEquals(33, message.getStringToInt32FieldMap().get("3").intValue());
   }
 
   private void updateMapValuesUsingMutableMap(TestMap.Builder builder) {
@@ -268,17 +268,17 @@ public class MapForProto2Test extends TestCase {
   }
 
   private void assertMapValuesCleared(TestMapOrBuilder testMapOrBuilder) {
-    assertEquals(0, testMapOrBuilder.getInt32ToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToStringField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToStringFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToStringFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToBytesField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToEnumField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToMessageField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldCount());
-    assertEquals(0, testMapOrBuilder.getStringToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getStringToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getStringToInt32FieldCount());
   }
 
@@ -293,13 +293,13 @@ public class MapForProto2Test extends TestCase {
   }
 
   private void assertMapsAreImmutable(TestMapOrBuilder testMapOrBuilder) {
-    assertImmutable(testMapOrBuilder.getInt32ToInt32Field(), 1, 2);
-    assertImmutable(testMapOrBuilder.getInt32ToStringField(), 1, "2");
-    assertImmutable(testMapOrBuilder.getInt32ToBytesField(), 1, TestUtil.toBytes("2"));
-    assertImmutable(testMapOrBuilder.getInt32ToEnumField(), 1, TestMap.EnumValue.FOO);
+    assertImmutable(testMapOrBuilder.getInt32ToInt32FieldMap(), 1, 2);
+    assertImmutable(testMapOrBuilder.getInt32ToStringFieldMap(), 1, "2");
+    assertImmutable(testMapOrBuilder.getInt32ToBytesFieldMap(), 1, TestUtil.toBytes("2"));
+    assertImmutable(testMapOrBuilder.getInt32ToEnumFieldMap(), 1, TestMap.EnumValue.FOO);
     assertImmutable(
-        testMapOrBuilder.getInt32ToMessageField(), 1, MessageValue.getDefaultInstance());
-    assertImmutable(testMapOrBuilder.getStringToInt32Field(), "1", 2);
+        testMapOrBuilder.getInt32ToMessageFieldMap(), 1, MessageValue.getDefaultInstance());
+    assertImmutable(testMapOrBuilder.getStringToInt32FieldMap(), "1", 2);
   }
 
   private <K, V> void assertImmutable(Map<K, V> map, K key, V value) {
@@ -874,8 +874,8 @@ public class MapForProto2Test extends TestCase {
     ByteString data = builder.build().toByteString();
 
     TestRecursiveMap message = TestRecursiveMap.parseFrom(data);
-    assertEquals(2, message.getRecursiveMapField().get(1).getValue());
-    assertEquals(4, message.getRecursiveMapField().get(3).getValue());
+    assertEquals(2, message.getRecursiveMapFieldMap().get(1).getValue());
+    assertEquals(4, message.getRecursiveMapFieldMap().get(3).getValue());
   }
 
   public void testIterationOrder() throws Exception {

java/core/src/test/java/com/google/protobuf/MapLiteTest.java

@@ -191,17 +191,17 @@ public final class MapLiteTest extends TestCase {
   }
 
   private void assertMapValuesCleared(TestMapOrBuilder testMapOrBuilder) {
-    assertEquals(0, testMapOrBuilder.getInt32ToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToStringField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToStringFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToStringFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToBytesField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToEnumField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToMessageField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldCount());
-    assertEquals(0, testMapOrBuilder.getStringToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getStringToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getStringToInt32FieldCount());
   }
 
@@ -232,13 +232,13 @@ public final class MapLiteTest extends TestCase {
   }
 
   private void assertMapsAreImmutable(TestMapOrBuilder testMapOrBuilder) {
-    assertImmutable(testMapOrBuilder.getInt32ToInt32Field(), 1, 2);
-    assertImmutable(testMapOrBuilder.getInt32ToStringField(), 1, "2");
-    assertImmutable(testMapOrBuilder.getInt32ToBytesField(), 1, TestUtil.toBytes("2"));
-    assertImmutable(testMapOrBuilder.getInt32ToEnumField(), 1, TestMap.EnumValue.FOO);
+    assertImmutable(testMapOrBuilder.getInt32ToInt32FieldMap(), 1, 2);
+    assertImmutable(testMapOrBuilder.getInt32ToStringFieldMap(), 1, "2");
+    assertImmutable(testMapOrBuilder.getInt32ToBytesFieldMap(), 1, TestUtil.toBytes("2"));
+    assertImmutable(testMapOrBuilder.getInt32ToEnumFieldMap(), 1, TestMap.EnumValue.FOO);
     assertImmutable(
-        testMapOrBuilder.getInt32ToMessageField(), 1, MessageValue.getDefaultInstance());
-    assertImmutable(testMapOrBuilder.getStringToInt32Field(), "1", 2);
+        testMapOrBuilder.getInt32ToMessageFieldMap(), 1, MessageValue.getDefaultInstance());
+    assertImmutable(testMapOrBuilder.getStringToInt32FieldMap(), "1", 2);
   }
 
   private <K, V> void assertImmutable(Map<K, V> map, K key, V value) {

java/core/src/test/java/com/google/protobuf/MapTest.java

@@ -271,17 +271,17 @@ public class MapTest extends TestCase {
   }
 
   private void assertMapValuesCleared(TestMapOrBuilder testMapOrBuilder) {
-    assertEquals(0, testMapOrBuilder.getInt32ToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToInt32FieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToStringField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToStringFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToStringFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToBytesField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToBytesFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToEnumField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToEnumFieldCount());
-    assertEquals(0, testMapOrBuilder.getInt32ToMessageField().size());
+    assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldMap().size());
     assertEquals(0, testMapOrBuilder.getInt32ToMessageFieldCount());
-    assertEquals(0, testMapOrBuilder.getStringToInt32Field().size());
+    assertEquals(0, testMapOrBuilder.getStringToInt32FieldMap().size());
     assertEquals(0, testMapOrBuilder.getStringToInt32FieldCount());
   }
 
@@ -296,13 +296,13 @@ public class MapTest extends TestCase {
   }
 
   private void assertMapsAreImmutable(TestMapOrBuilder testMapOrBuilder) {
-    assertImmutable(testMapOrBuilder.getInt32ToInt32Field(), 1, 2);
-    assertImmutable(testMapOrBuilder.getInt32ToStringField(), 1, "2");
-    assertImmutable(testMapOrBuilder.getInt32ToBytesField(), 1, TestUtil.toBytes("2"));
-    assertImmutable(testMapOrBuilder.getInt32ToEnumField(), 1, TestMap.EnumValue.FOO);
+    assertImmutable(testMapOrBuilder.getInt32ToInt32FieldMap(), 1, 2);
+    assertImmutable(testMapOrBuilder.getInt32ToStringFieldMap(), 1, "2");
+    assertImmutable(testMapOrBuilder.getInt32ToBytesFieldMap(), 1, TestUtil.toBytes("2"));
+    assertImmutable(testMapOrBuilder.getInt32ToEnumFieldMap(), 1, TestMap.EnumValue.FOO);
     assertImmutable(
-        testMapOrBuilder.getInt32ToMessageField(), 1, MessageValue.getDefaultInstance());
-    assertImmutable(testMapOrBuilder.getStringToInt32Field(), "1", 2);
+        testMapOrBuilder.getInt32ToMessageFieldMap(), 1, MessageValue.getDefaultInstance());
+    assertImmutable(testMapOrBuilder.getStringToInt32FieldMap(), "1", 2);
   }
 
   private <K, V> void assertImmutable(Map<K, V> map, K key, V value) {

java/core/src/test/java/com/google/protobuf/TestUtil.java

@@ -260,8 +260,8 @@ public final class TestUtil {
       TestRequired.newBuilder().setA(1).setB(2).setC(3).build();
 
   /** Helper to convert a String to ByteString. */
-  static ByteString toBytes(String str) {
-    return ByteString.copyFrom(str.getBytes(Internal.UTF_8));
+  public static ByteString toBytes(String str) {
+    return ByteString.copyFromUtf8(str);
   }
 
   // BEGIN FULL-RUNTIME

java/core/src/test/java/com/google/protobuf/TestUtilLite.java

@@ -142,8 +142,8 @@ public final class TestUtilLite {
   private TestUtilLite() {}
 
   /** Helper to convert a String to ByteString. */
-  static ByteString toBytes(String str) {
-    return ByteString.copyFrom(str.getBytes(Internal.UTF_8));
+  public static ByteString toBytes(String str) {
+    return ByteString.copyFromUtf8(str);
   }
 
   /**

java/util/src/main/java/com/google/protobuf/util/Durations.java

@@ -44,6 +44,7 @@ import static com.google.protobuf.util.Timestamps.NANOS_PER_SECOND;
 
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.protobuf.Duration;
+import java.io.Serializable;
 import java.text.ParseException;
 import java.util.Comparator;
 
@@ -72,23 +73,25 @@ public final class Durations {
 
   private Durations() {}
 
-  private static final Comparator<Duration> COMPARATOR =
-      new Comparator<Duration>() {
-        @Override
-        public int compare(Duration d1, Duration d2) {
-          checkValid(d1);
-          checkValid(d2);
-          int secDiff = Long.compare(d1.getSeconds(), d2.getSeconds());
-          return (secDiff != 0) ? secDiff : Integer.compare(d1.getNanos(), d2.getNanos());
-        }
-      };
+  private static enum DurationComparator implements Comparator<Duration>, Serializable {
+    INSTANCE;
+
+    @Override
+    public int compare(Duration d1, Duration d2) {
+      checkValid(d1);
+      checkValid(d2);
+      int secDiff = Long.compare(d1.getSeconds(), d2.getSeconds());
+      return (secDiff != 0) ? secDiff : Integer.compare(d1.getNanos(), d2.getNanos());
+    }
+  }
 
   /**
    * Returns a {@link Comparator} for {@link Duration}s which sorts in increasing chronological
-   * order. Nulls and invalid {@link Duration}s are not allowed (see {@link #isValid}).
+   * order. Nulls and invalid {@link Duration}s are not allowed (see {@link #isValid}). The returned
+   * comparator is serializable.
    */
   public static Comparator<Duration> comparator() {
-    return COMPARATOR;
+    return DurationComparator.INSTANCE;
   }
 
   /**
@@ -99,7 +102,7 @@ public final class Durations {
    *     and a value greater than {@code 0} if {@code x > y}
    */
   public static int compare(Duration x, Duration y) {
-    return COMPARATOR.compare(x, y);
+    return DurationComparator.INSTANCE.compare(x, y);
   }
 
   /**

java/util/src/main/java/com/google/protobuf/util/Timestamps.java

@@ -39,6 +39,7 @@ import static com.google.common.math.LongMath.checkedSubtract;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.protobuf.Duration;
 import com.google.protobuf.Timestamp;
+import java.io.Serializable;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Comparator;
@@ -100,24 +101,25 @@ public final class Timestamps {
 
   private Timestamps() {}
 
-  private static final Comparator<Timestamp> COMPARATOR =
-      new Comparator<Timestamp>() {
-        @Override
-        public int compare(Timestamp t1, Timestamp t2) {
-          checkValid(t1);
-          checkValid(t2);
-          int secDiff = Long.compare(t1.getSeconds(), t2.getSeconds());
-          return (secDiff != 0) ? secDiff : Integer.compare(t1.getNanos(), t2.getNanos());
-        }
-      };
+  private static enum TimestampComparator implements Comparator<Timestamp>, Serializable {
+    INSTANCE;
+
+    @Override
+    public int compare(Timestamp t1, Timestamp t2) {
+      checkValid(t1);
+      checkValid(t2);
+      int secDiff = Long.compare(t1.getSeconds(), t2.getSeconds());
+      return (secDiff != 0) ? secDiff : Integer.compare(t1.getNanos(), t2.getNanos());
+    }
+  }
 
   /**
    * Returns a {@link Comparator} for {@link Timestamp Timestamps} which sorts in increasing
    * chronological order. Nulls and invalid {@link Timestamp Timestamps} are not allowed (see
-   * {@link #isValid}).
+   * {@link #isValid}). The returned comparator is serializable.
    */
   public static Comparator<Timestamp> comparator() {
-    return COMPARATOR;
+    return TimestampComparator.INSTANCE;
   }
 
   /**
@@ -128,7 +130,7 @@ public final class Timestamps {
    *     and a value greater than {@code 0} if {@code x > y}
    */
   public static int compare(Timestamp x, Timestamp y) {
-    return COMPARATOR.compare(x, y);
+    return TimestampComparator.INSTANCE.compare(x, y);
   }
 
   /**

python/google/protobuf/internal/containers.py

@@ -231,6 +231,9 @@ class BaseContainer(object):
       kwargs['cmp'] = kwargs.pop('sort_function')
     self._values.sort(*args, **kwargs)
 
+  def reverse(self):
+    self._values.reverse()
+
 
 collections_abc.MutableSequence.register(BaseContainer)
 

python/google/protobuf/internal/reflection_test.py

@@ -1311,6 +1311,38 @@ class Proto2ReflectionTest(unittest.TestCase):
     # Remove a non-existent element.
     self.assertRaises(ValueError, proto.repeated_int32.remove, 123)
 
+  def testRepeatedScalarsReverse_Empty(self):
+    proto = unittest_pb2.TestAllTypes()
+
+    self.assertFalse(proto.repeated_int32)
+    self.assertEqual(0, len(proto.repeated_int32))
+
+    self.assertIsNone(proto.repeated_int32.reverse())
+
+    self.assertFalse(proto.repeated_int32)
+    self.assertEqual(0, len(proto.repeated_int32))
+
+  def testRepeatedScalarsReverse_NonEmpty(self):
+    proto = unittest_pb2.TestAllTypes()
+
+    self.assertFalse(proto.repeated_int32)
+    self.assertEqual(0, len(proto.repeated_int32))
+
+    proto.repeated_int32.append(1)
+    proto.repeated_int32.append(2)
+    proto.repeated_int32.append(3)
+    proto.repeated_int32.append(4)
+
+    self.assertEqual(4, len(proto.repeated_int32))
+
+    self.assertIsNone(proto.repeated_int32.reverse())
+
+    self.assertEqual(4, len(proto.repeated_int32))
+    self.assertEqual(4, proto.repeated_int32[0])
+    self.assertEqual(3, proto.repeated_int32[1])
+    self.assertEqual(2, proto.repeated_int32[2])
+    self.assertEqual(1, proto.repeated_int32[3])
+
   def testRepeatedComposites(self):
     proto = unittest_pb2.TestAllTypes()
     self.assertFalse(proto.repeated_nested_message)
@@ -1423,6 +1455,35 @@ class Proto2ReflectionTest(unittest.TestCase):
     self.assertEqual(1, len(proto.repeated_nested_message))
     self.assertEqual(m1, proto.repeated_nested_message[0])
 
+  def testRepeatedCompositeReverse_Empty(self):
+    proto = unittest_pb2.TestAllTypes()
+
+    self.assertFalse(proto.repeated_nested_message)
+    self.assertEqual(0, len(proto.repeated_nested_message))
+
+    self.assertIsNone(proto.repeated_nested_message.reverse())
+
+    self.assertFalse(proto.repeated_nested_message)
+    self.assertEqual(0, len(proto.repeated_nested_message))
+
+  def testRepeatedCompositeReverse_NonEmpty(self):
+    proto = unittest_pb2.TestAllTypes()
+
+    self.assertFalse(proto.repeated_nested_message)
+    self.assertEqual(0, len(proto.repeated_nested_message))
+
+    m0 = proto.repeated_nested_message.add()
+    m0.bb = len(proto.repeated_nested_message)
+    m1 = proto.repeated_nested_message.add()
+    m1.bb = len(proto.repeated_nested_message)
+    m2 = proto.repeated_nested_message.add()
+    m2.bb = len(proto.repeated_nested_message)
+    self.assertListsEqual([m0, m1, m2], proto.repeated_nested_message)
+
+    self.assertIsNone(proto.repeated_nested_message.reverse())
+
+    self.assertListsEqual([m2, m1, m0], proto.repeated_nested_message)
+
   def testHandWrittenReflection(self):
     # Hand written extensions are only supported by the pure-Python
     # implementation of the API.
@@ -3061,10 +3122,10 @@ class SerializationTest(unittest.TestCase):
       unittest_pb2.ForeignMessage.c.__get__(msg)
     except TypeError:
       pass  # The cpp implementation cannot mix fields from other messages.
-            # This test exercises a specific check that avoids a crash.
+      # This test exercises a specific check that avoids a crash.
     else:
       pass  # The python implementation allows fields from other messages.
-            # This is useless, but works.
+      # This is useless, but works.
 
   def testInitKwargs(self):
     proto = unittest_pb2.TestAllTypes(

python/google/protobuf/pyext/repeated_composite_container.cc

@@ -77,8 +77,7 @@ static Py_ssize_t Length(PyObject* pself) {
 
 PyObject* Add(RepeatedCompositeContainer* self, PyObject* args,
               PyObject* kwargs) {
-  if (cmessage::AssureWritable(self->parent) == -1)
-    return NULL;
+  if (cmessage::AssureWritable(self->parent) == -1) return nullptr;
   Message* message = self->parent->message;
 
   Message* sub_message =
@@ -93,7 +92,7 @@ PyObject* Add(RepeatedCompositeContainer* self, PyObject* args,
     message->GetReflection()->RemoveLast(
         message, self->parent_field_descriptor);
     Py_DECREF(cmsg);
-    return NULL;
+    return nullptr;
   }
 
   return cmsg->AsPyObject();
@@ -172,28 +171,28 @@ static PyObject* Insert(PyObject* pself, PyObject* args) {
 PyObject* Extend(RepeatedCompositeContainer* self, PyObject* value) {
   cmessage::AssureWritable(self->parent);
   ScopedPyObjectPtr iter(PyObject_GetIter(value));
-  if (iter == NULL) {
+  if (iter == nullptr) {
     PyErr_SetString(PyExc_TypeError, "Value must be iterable");
-    return NULL;
+    return nullptr;
   }
   ScopedPyObjectPtr next;
-  while ((next.reset(PyIter_Next(iter.get()))) != NULL) {
+  while ((next.reset(PyIter_Next(iter.get()))) != nullptr) {
     if (!PyObject_TypeCheck(next.get(), CMessage_Type)) {
       PyErr_SetString(PyExc_TypeError, "Not a cmessage");
-      return NULL;
+      return nullptr;
     }
-    ScopedPyObjectPtr new_message(Add(self, NULL, NULL));
-    if (new_message == NULL) {
-      return NULL;
+    ScopedPyObjectPtr new_message(Add(self, nullptr, nullptr));
+    if (new_message == nullptr) {
+      return nullptr;
     }
     CMessage* new_cmessage = reinterpret_cast<CMessage*>(new_message.get());
     if (ScopedPyObjectPtr(cmessage::MergeFrom(new_cmessage, next.get())) ==
-        NULL) {
-      return NULL;
+        nullptr) {
+      return nullptr;
     }
   }
   if (PyErr_Occurred()) {
-    return NULL;
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -220,7 +219,7 @@ static PyObject* GetItem(RepeatedCompositeContainer* self, Py_ssize_t index,
   }
   if (index < 0 || index >= length) {
     PyErr_Format(PyExc_IndexError, "list index (%zd) out of range", index);
-    return NULL;
+    return nullptr;
   }
   Message* message = self->parent->message;
   Message* sub_message = message->GetReflection()->MutableRepeatedMessage(
@@ -240,7 +239,7 @@ PyObject* Subscript(RepeatedCompositeContainer* self, PyObject* item) {
   if (PyIndex_Check(item)) {
     Py_ssize_t index;
     index = PyNumber_AsSsize_t(item, PyExc_IndexError);
-    if (index == -1 && PyErr_Occurred()) return NULL;
+    if (index == -1 && PyErr_Occurred()) return nullptr;
     if (index < 0) index += length;
     return GetItem(self, index, length);
   } else if (PySlice_Check(item)) {
@@ -254,14 +253,14 @@ PyObject* Subscript(RepeatedCompositeContainer* self, PyObject* item) {
     if (PySlice_GetIndicesEx(reinterpret_cast<PySliceObject*>(item),
                              length, &from, &to, &step, &slicelength) == -1) {
 #endif
-      return NULL;
+      return nullptr;
     }
 
     if (slicelength <= 0) {
       return PyList_New(0);
     } else {
       result = PyList_New(slicelength);
-      if (!result) return NULL;
+      if (!result) return nullptr;
 
       for (cur = from, i = 0; i < slicelength; cur += step, i++) {
         PyList_SET_ITEM(result, i, GetItem(self, cur, length));
@@ -272,7 +271,7 @@ PyObject* Subscript(RepeatedCompositeContainer* self, PyObject* item) {
   } else {
     PyErr_Format(PyExc_TypeError, "indices must be integers, not %.200s",
                  item->ob_type->tp_name);
-    return NULL;
+    return nullptr;
   }
 }
 
@@ -283,7 +282,7 @@ static PyObject* SubscriptMethod(PyObject* self, PyObject* slice) {
 int AssignSubscript(RepeatedCompositeContainer* self,
                     PyObject* slice,
                     PyObject* value) {
-  if (value != NULL) {
+  if (value != nullptr) {
     PyErr_SetString(PyExc_TypeError, "does not support assignment");
     return -1;
   }
@@ -305,23 +304,23 @@ static PyObject* Remove(PyObject* pself, PyObject* value) {
 
   for (Py_ssize_t i = 0; i < len; i++) {
     ScopedPyObjectPtr item(GetItem(self, i, len));
-    if (item == NULL) {
-      return NULL;
+    if (item == nullptr) {
+      return nullptr;
     }
     int result = PyObject_RichCompareBool(item.get(), value, Py_EQ);
     if (result < 0) {
-      return NULL;
+      return nullptr;
     }
     if (result) {
       ScopedPyObjectPtr py_index(PyLong_FromSsize_t(i));
-      if (AssignSubscript(self, py_index.get(), NULL) < 0) {
-        return NULL;
+      if (AssignSubscript(self, py_index.get(), nullptr) < 0) {
+        return nullptr;
       }
       Py_RETURN_NONE;
     }
   }
   PyErr_SetString(PyExc_ValueError, "Item to delete not in list");
-  return NULL;
+  return nullptr;
 }
 
 static PyObject* RichCompare(PyObject* pself, PyObject* other, int opid) {
@@ -332,23 +331,23 @@ static PyObject* RichCompare(PyObject* pself, PyObject* other, int opid) {
     PyErr_SetString(PyExc_TypeError,
                     "Can only compare repeated composite fields "
                     "against other repeated composite fields.");
-    return NULL;
+    return nullptr;
   }
   if (opid == Py_EQ || opid == Py_NE) {
     // TODO(anuraag): Don't make new lists just for this...
-    ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-    if (full_slice == NULL) {
-      return NULL;
+    ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+    if (full_slice == nullptr) {
+      return nullptr;
     }
     ScopedPyObjectPtr list(Subscript(self, full_slice.get()));
-    if (list == NULL) {
-      return NULL;
+    if (list == nullptr) {
+      return nullptr;
     }
     ScopedPyObjectPtr other_list(
         Subscript(reinterpret_cast<RepeatedCompositeContainer*>(other),
                   full_slice.get()));
-    if (other_list == NULL) {
-      return NULL;
+    if (other_list == nullptr) {
+      return nullptr;
     }
     return PyObject_RichCompare(list.get(), other_list.get(), opid);
   } else {
@@ -358,14 +357,14 @@ static PyObject* RichCompare(PyObject* pself, PyObject* other, int opid) {
 }
 
 static PyObject* ToStr(PyObject* pself) {
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-  if (full_slice == NULL) {
-    return NULL;
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr list(Subscript(
       reinterpret_cast<RepeatedCompositeContainer*>(pself), full_slice.get()));
-  if (list == NULL) {
-    return NULL;
+  if (list == nullptr) {
+    return nullptr;
   }
   return PyObject_Repr(list.get());
 }
@@ -400,13 +399,12 @@ static int SortPythonMessages(RepeatedCompositeContainer* self,
                                PyObject* kwds) {
   ScopedPyObjectPtr child_list(
       PySequence_List(reinterpret_cast<PyObject*>(self)));
-  if (child_list == NULL) {
+  if (child_list == nullptr) {
     return -1;
   }
   ScopedPyObjectPtr m(PyObject_GetAttrString(child_list.get(), "sort"));
-  if (m == NULL)
-    return -1;
-  if (ScopedPyObjectPtr(PyObject_Call(m.get(), args, kwds)) == NULL)
+  if (m == nullptr) return -1;
+  if (ScopedPyObjectPtr(PyObject_Call(m.get(), args, kwds)) == nullptr)
     return -1;
   ReorderAttached(self, child_list.get());
   return 0;
@@ -418,9 +416,9 @@ static PyObject* Sort(PyObject* pself, PyObject* args, PyObject* kwds) {
 
   // Support the old sort_function argument for backwards
   // compatibility.
-  if (kwds != NULL) {
+  if (kwds != nullptr) {
     PyObject* sort_func = PyDict_GetItemString(kwds, "sort_function");
-    if (sort_func != NULL) {
+    if (sort_func != nullptr) {
       // Must set before deleting as sort_func is a borrowed reference
       // and kwds might be the only thing keeping it alive.
       PyDict_SetItemString(kwds, "cmp", sort_func);
@@ -429,7 +427,35 @@ static PyObject* Sort(PyObject* pself, PyObject* args, PyObject* kwds) {
   }
 
   if (SortPythonMessages(self, args, kwds) < 0) {
-    return NULL;
+    return nullptr;
+  }
+  Py_RETURN_NONE;
+}
+
+// ---------------------------------------------------------------------
+// reverse()
+
+// Returns 0 if successful; returns -1 and sets an exception if
+// unsuccessful.
+static int ReversePythonMessages(RepeatedCompositeContainer* self) {
+  ScopedPyObjectPtr child_list(
+      PySequence_List(reinterpret_cast<PyObject*>(self)));
+  if (child_list == nullptr) {
+    return -1;
+  }
+  if (ScopedPyObjectPtr(
+          PyObject_CallMethod(child_list.get(), "reverse", nullptr)) == nullptr)
+    return -1;
+  ReorderAttached(self, child_list.get());
+  return 0;
+}
+
+static PyObject* Reverse(PyObject* pself) {
+  RepeatedCompositeContainer* self =
+      reinterpret_cast<RepeatedCompositeContainer*>(pself);
+
+  if (ReversePythonMessages(self) < 0) {
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -448,17 +474,17 @@ static PyObject* Pop(PyObject* pself, PyObject* args) {
 
   Py_ssize_t index = -1;
   if (!PyArg_ParseTuple(args, "|n", &index)) {
-    return NULL;
+    return nullptr;
   }
   Py_ssize_t length = Length(pself);
   if (index < 0) index += length;
   PyObject* item = GetItem(self, index, length);
-  if (item == NULL) {
-    return NULL;
+  if (item == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr py_index(PyLong_FromSsize_t(index));
-  if (AssignSubscript(self, py_index.get(), NULL) < 0) {
-    return NULL;
+  if (AssignSubscript(self, py_index.get(), nullptr) < 0) {
+    return nullptr;
   }
   return item;
 }
@@ -473,14 +499,14 @@ RepeatedCompositeContainer *NewContainer(
     const FieldDescriptor* parent_field_descriptor,
     CMessageClass* child_message_class) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
-    return NULL;
+    return nullptr;
   }
 
   RepeatedCompositeContainer* self =
       reinterpret_cast<RepeatedCompositeContainer*>(
           PyType_GenericAlloc(&RepeatedCompositeContainer_Type, 0));
-  if (self == NULL) {
-    return NULL;
+  if (self == nullptr) {
+    return nullptr;
   }
 
   Py_INCREF(parent);
@@ -500,10 +526,10 @@ static void Dealloc(PyObject* pself) {
 }
 
 static PySequenceMethods SqMethods = {
-  Length,                 /* sq_length */
-  0,                      /* sq_concat */
-  0,                      /* sq_repeat */
-  Item                    /* sq_item */
+    Length,  /* sq_length */
+    nullptr, /* sq_concat */
+    nullptr, /* sq_repeat */
+    Item     /* sq_item */
 };
 
 static PyMappingMethods MpMethods = {
@@ -513,66 +539,65 @@ static PyMappingMethods MpMethods = {
 };
 
 static PyMethodDef Methods[] = {
-  { "__deepcopy__", DeepCopy, METH_VARARGS,
-    "Makes a deep copy of the class." },
-  { "add", (PyCFunction)AddMethod, METH_VARARGS | METH_KEYWORDS,
-    "Adds an object to the repeated container." },
-  { "append", AppendMethod, METH_O,
-    "Appends a message to the end of the repeated container."},
-  { "insert", Insert, METH_VARARGS,
-    "Inserts a message before the specified index." },
-  { "extend", ExtendMethod, METH_O,
-    "Adds objects to the repeated container." },
-  { "pop", Pop, METH_VARARGS,
-    "Removes an object from the repeated container and returns it." },
-  { "remove", Remove, METH_O,
-    "Removes an object from the repeated container." },
-  { "sort", (PyCFunction)Sort, METH_VARARGS | METH_KEYWORDS,
-    "Sorts the repeated container." },
-  { "MergeFrom", MergeFromMethod, METH_O,
-    "Adds objects to the repeated container." },
-  { NULL, NULL }
-};
+    {"__deepcopy__", DeepCopy, METH_VARARGS, "Makes a deep copy of the class."},
+    {"add", reinterpret_cast<PyCFunction>(AddMethod),
+     METH_VARARGS | METH_KEYWORDS, "Adds an object to the repeated container."},
+    {"append", AppendMethod, METH_O,
+     "Appends a message to the end of the repeated container."},
+    {"insert", Insert, METH_VARARGS,
+     "Inserts a message before the specified index."},
+    {"extend", ExtendMethod, METH_O, "Adds objects to the repeated container."},
+    {"pop", Pop, METH_VARARGS,
+     "Removes an object from the repeated container and returns it."},
+    {"remove", Remove, METH_O,
+     "Removes an object from the repeated container."},
+    {"sort", reinterpret_cast<PyCFunction>(Sort), METH_VARARGS | METH_KEYWORDS,
+     "Sorts the repeated container."},
+    {"reverse", reinterpret_cast<PyCFunction>(Reverse), METH_NOARGS,
+     "Reverses elements order of the repeated container."},
+    {"MergeFrom", MergeFromMethod, METH_O,
+     "Adds objects to the repeated container."},
+    {nullptr, nullptr}};
 
 }  // namespace repeated_composite_container
 
 PyTypeObject RepeatedCompositeContainer_Type = {
-  PyVarObject_HEAD_INIT(&PyType_Type, 0)
-  FULL_MODULE_NAME ".RepeatedCompositeContainer",  // tp_name
-  sizeof(RepeatedCompositeContainer),  // tp_basicsize
-  0,                                   //  tp_itemsize
-  repeated_composite_container::Dealloc,  //  tp_dealloc
-  0,                                   //  tp_print
-  0,                                   //  tp_getattr
-  0,                                   //  tp_setattr
-  0,                                   //  tp_compare
-  repeated_composite_container::ToStr,      //  tp_repr
-  0,                                   //  tp_as_number
-  &repeated_composite_container::SqMethods,   //  tp_as_sequence
-  &repeated_composite_container::MpMethods,   //  tp_as_mapping
-  PyObject_HashNotImplemented,         //  tp_hash
-  0,                                   //  tp_call
-  0,                                   //  tp_str
-  0,                                   //  tp_getattro
-  0,                                   //  tp_setattro
-  0,                                   //  tp_as_buffer
-  Py_TPFLAGS_DEFAULT,                  //  tp_flags
-  "A Repeated scalar container",       //  tp_doc
-  0,                                   //  tp_traverse
-  0,                                   //  tp_clear
-  repeated_composite_container::RichCompare,  //  tp_richcompare
-  0,                                   //  tp_weaklistoffset
-  0,                                   //  tp_iter
-  0,                                   //  tp_iternext
-  repeated_composite_container::Methods,   //  tp_methods
-  0,                                   //  tp_members
-  0,                                   //  tp_getset
-  0,                                   //  tp_base
-  0,                                   //  tp_dict
-  0,                                   //  tp_descr_get
-  0,                                   //  tp_descr_set
-  0,                                   //  tp_dictoffset
-  0,                                   //  tp_init
+    PyVarObject_HEAD_INIT(&PyType_Type, 0) FULL_MODULE_NAME
+    ".RepeatedCompositeContainer",              // tp_name
+    sizeof(RepeatedCompositeContainer),         // tp_basicsize
+    0,                                          //  tp_itemsize
+    repeated_composite_container::Dealloc,      //  tp_dealloc
+    nullptr,                                    //  tp_print
+    nullptr,                                    //  tp_getattr
+    nullptr,                                    //  tp_setattr
+    nullptr,                                    //  tp_compare
+    repeated_composite_container::ToStr,        //  tp_repr
+    nullptr,                                    //  tp_as_number
+    &repeated_composite_container::SqMethods,   //  tp_as_sequence
+    &repeated_composite_container::MpMethods,   //  tp_as_mapping
+    PyObject_HashNotImplemented,                //  tp_hash
+    nullptr,                                    //  tp_call
+    nullptr,                                    //  tp_str
+    nullptr,                                    //  tp_getattro
+    nullptr,                                    //  tp_setattro
+    nullptr,                                    //  tp_as_buffer
+    Py_TPFLAGS_DEFAULT,                         //  tp_flags
+    "A Repeated scalar container",              //  tp_doc
+    nullptr,                                    //  tp_traverse
+    nullptr,                                    //  tp_clear
+    repeated_composite_container::RichCompare,  //  tp_richcompare
+    0,                                          //  tp_weaklistoffset
+    nullptr,                                    //  tp_iter
+    nullptr,                                    //  tp_iternext
+    repeated_composite_container::Methods,      //  tp_methods
+    nullptr,                                    //  tp_members
+    nullptr,                                    //  tp_getset
+    nullptr,                                    //  tp_base
+    nullptr,                                    //  tp_dict
+    nullptr,                                    //  tp_descr_get
+    nullptr,                                    //  tp_descr_set
+    0,                                          //  tp_dictoffset
+    nullptr,                                    //  tp_init
 };
 
 }  // namespace python

python/google/protobuf/pyext/repeated_scalar_container.cc

@@ -46,13 +46,13 @@
 #include <google/protobuf/pyext/scoped_pyobject_ptr.h>
 
 #if PY_MAJOR_VERSION >= 3
-  #define PyInt_FromLong PyLong_FromLong
-  #if PY_VERSION_HEX < 0x03030000
-    #error "Python 3.0 - 3.2 are not supported."
-  #else
-  #define PyString_AsString(ob) \
-    (PyUnicode_Check(ob)? PyUnicode_AsUTF8(ob): PyBytes_AsString(ob))
-  #endif
+#define PyInt_FromLong PyLong_FromLong
+#if PY_VERSION_HEX < 0x03030000
+#error "Python 3.0 - 3.2 are not supported."
+#else
+#define PyString_AsString(ob) \
+  (PyUnicode_Check(ob) ? PyUnicode_AsUTF8(ob) : PyBytes_AsString(ob))
+#endif
 #endif
 
 namespace google {
@@ -61,13 +61,13 @@ namespace python {
 
 namespace repeated_scalar_container {
 
-static int InternalAssignRepeatedField(
-    RepeatedScalarContainer* self, PyObject* list) {
+static int InternalAssignRepeatedField(RepeatedScalarContainer* self,
+                                       PyObject* list) {
   Message* message = self->parent->message;
   message->GetReflection()->ClearField(message, self->parent_field_descriptor);
   for (Py_ssize_t i = 0; i < PyList_GET_SIZE(list); ++i) {
     PyObject* value = PyList_GET_ITEM(list, i);
-    if (ScopedPyObjectPtr(Append(self, value)) == NULL) {
+    if (ScopedPyObjectPtr(Append(self, value)) == nullptr) {
       return -1;
     }
   }
@@ -96,13 +96,12 @@ static int AssignItem(PyObject* pself, Py_ssize_t index, PyObject* arg) {
     index = field_size + index;
   }
   if (index < 0 || index >= field_size) {
-    PyErr_Format(PyExc_IndexError,
-                 "list assignment index (%d) out of range",
+    PyErr_Format(PyExc_IndexError, "list assignment index (%d) out of range",
                  static_cast<int>(index));
     return -1;
   }
 
-  if (arg == NULL) {
+  if (arg == nullptr) {
     ScopedPyObjectPtr py_index(PyLong_FromLong(index));
     return cmessage::DeleteRepeatedField(self->parent, field_descriptor,
                                          py_index.get());
@@ -150,8 +149,8 @@ static int AssignItem(PyObject* pself, Py_ssize_t index, PyObject* arg) {
       break;
     }
     case FieldDescriptor::CPPTYPE_STRING: {
-      if (!CheckAndSetString(
-          arg, message, field_descriptor, reflection, false, index)) {
+      if (!CheckAndSetString(arg, message, field_descriptor, reflection, false,
+                             index)) {
         return -1;
       }
       break;
@@ -165,12 +164,12 @@ static int AssignItem(PyObject* pself, Py_ssize_t index, PyObject* arg) {
         const EnumDescriptor* enum_descriptor = field_descriptor->enum_type();
         const EnumValueDescriptor* enum_value =
             enum_descriptor->FindValueByNumber(value);
-        if (enum_value != NULL) {
+        if (enum_value != nullptr) {
           reflection->SetRepeatedEnum(message, field_descriptor, index,
                                       enum_value);
         } else {
           ScopedPyObjectPtr s(PyObject_Str(arg));
-          if (s != NULL) {
+          if (s != nullptr) {
             PyErr_Format(PyExc_ValueError, "Unknown enum value: %s",
                          PyString_AsString(s.get()));
           }
@@ -180,9 +179,9 @@ static int AssignItem(PyObject* pself, Py_ssize_t index, PyObject* arg) {
       break;
     }
     default:
-      PyErr_Format(
-          PyExc_SystemError, "Adding value to a field of unknown type %d",
-          field_descriptor->cpp_type());
+      PyErr_Format(PyExc_SystemError,
+                   "Adding value to a field of unknown type %d",
+                   field_descriptor->cpp_type());
       return -1;
   }
   return 0;
@@ -201,60 +200,58 @@ static PyObject* Item(PyObject* pself, Py_ssize_t index) {
     index = field_size + index;
   }
   if (index < 0 || index >= field_size) {
-    PyErr_Format(PyExc_IndexError,
-                 "list index (%zd) out of range",
-                 index);
-    return NULL;
+    PyErr_Format(PyExc_IndexError, "list index (%zd) out of range", index);
+    return nullptr;
   }
 
-  PyObject* result = NULL;
+  PyObject* result = nullptr;
   switch (field_descriptor->cpp_type()) {
     case FieldDescriptor::CPPTYPE_INT32: {
-      int32 value = reflection->GetRepeatedInt32(
-          *message, field_descriptor, index);
+      int32 value =
+          reflection->GetRepeatedInt32(*message, field_descriptor, index);
       result = PyInt_FromLong(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_INT64: {
-      int64 value = reflection->GetRepeatedInt64(
-          *message, field_descriptor, index);
+      int64 value =
+          reflection->GetRepeatedInt64(*message, field_descriptor, index);
       result = PyLong_FromLongLong(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_UINT32: {
-      uint32 value = reflection->GetRepeatedUInt32(
-          *message, field_descriptor, index);
+      uint32 value =
+          reflection->GetRepeatedUInt32(*message, field_descriptor, index);
       result = PyLong_FromLongLong(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_UINT64: {
-      uint64 value = reflection->GetRepeatedUInt64(
-          *message, field_descriptor, index);
+      uint64 value =
+          reflection->GetRepeatedUInt64(*message, field_descriptor, index);
       result = PyLong_FromUnsignedLongLong(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_FLOAT: {
-      float value = reflection->GetRepeatedFloat(
-          *message, field_descriptor, index);
+      float value =
+          reflection->GetRepeatedFloat(*message, field_descriptor, index);
       result = PyFloat_FromDouble(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_DOUBLE: {
-      double value = reflection->GetRepeatedDouble(
-          *message, field_descriptor, index);
+      double value =
+          reflection->GetRepeatedDouble(*message, field_descriptor, index);
       result = PyFloat_FromDouble(value);
       break;
     }
     case FieldDescriptor::CPPTYPE_BOOL: {
-      bool value = reflection->GetRepeatedBool(
-          *message, field_descriptor, index);
+      bool value =
+          reflection->GetRepeatedBool(*message, field_descriptor, index);
       result = PyBool_FromLong(value ? 1 : 0);
       break;
     }
     case FieldDescriptor::CPPTYPE_ENUM: {
       const EnumValueDescriptor* enum_value =
-          message->GetReflection()->GetRepeatedEnum(
-              *message, field_descriptor, index);
+          message->GetReflection()->GetRepeatedEnum(*message, field_descriptor,
+                                                    index);
       result = PyInt_FromLong(enum_value->number());
       break;
     }
@@ -266,10 +263,9 @@ static PyObject* Item(PyObject* pself, Py_ssize_t index) {
       break;
     }
     default:
-      PyErr_Format(
-          PyExc_SystemError,
-          "Getting value from a repeated field of unknown type %d",
-          field_descriptor->cpp_type());
+      PyErr_Format(PyExc_SystemError,
+                   "Getting value from a repeated field of unknown type %d",
+                   field_descriptor->cpp_type());
   }
 
   return result;
@@ -287,23 +283,23 @@ static PyObject* Subscript(PyObject* pself, PyObject* slice) {
     from = to = PyInt_AsLong(slice);
   } else  // NOLINT
 #endif
-  if (PyLong_Check(slice)) {
+      if (PyLong_Check(slice)) {
     from = to = PyLong_AsLong(slice);
   } else if (PySlice_Check(slice)) {
     length = Len(pself);
 #if PY_MAJOR_VERSION >= 3
-    if (PySlice_GetIndicesEx(slice,
-                             length, &from, &to, &step, &slicelength) == -1) {
+    if (PySlice_GetIndicesEx(slice, length, &from, &to, &step, &slicelength) ==
+        -1) {
 #else
-    if (PySlice_GetIndicesEx(reinterpret_cast<PySliceObject*>(slice),
-                             length, &from, &to, &step, &slicelength) == -1) {
+    if (PySlice_GetIndicesEx(reinterpret_cast<PySliceObject*>(slice), length,
+                             &from, &to, &step, &slicelength) == -1) {
 #endif
-      return NULL;
+      return nullptr;
     }
     return_list = true;
   } else {
     PyErr_SetString(PyExc_TypeError, "list indices must be integers");
-    return NULL;
+    return nullptr;
   }
 
   if (!return_list) {
@@ -311,8 +307,8 @@ static PyObject* Subscript(PyObject* pself, PyObject* slice) {
   }
 
   PyObject* list = PyList_New(0);
-  if (list == NULL) {
-    return NULL;
+  if (list == nullptr) {
+    return nullptr;
   }
   if (from <= to) {
     if (step < 0) {
@@ -348,73 +344,73 @@ PyObject* Append(RepeatedScalarContainer* self, PyObject* item) {
   const Reflection* reflection = message->GetReflection();
   switch (field_descriptor->cpp_type()) {
     case FieldDescriptor::CPPTYPE_INT32: {
-      GOOGLE_CHECK_GET_INT32(item, value, NULL);
+      GOOGLE_CHECK_GET_INT32(item, value, nullptr);
       reflection->AddInt32(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_INT64: {
-      GOOGLE_CHECK_GET_INT64(item, value, NULL);
+      GOOGLE_CHECK_GET_INT64(item, value, nullptr);
       reflection->AddInt64(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_UINT32: {
-      GOOGLE_CHECK_GET_UINT32(item, value, NULL);
+      GOOGLE_CHECK_GET_UINT32(item, value, nullptr);
       reflection->AddUInt32(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_UINT64: {
-      GOOGLE_CHECK_GET_UINT64(item, value, NULL);
+      GOOGLE_CHECK_GET_UINT64(item, value, nullptr);
       reflection->AddUInt64(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_FLOAT: {
-      GOOGLE_CHECK_GET_FLOAT(item, value, NULL);
+      GOOGLE_CHECK_GET_FLOAT(item, value, nullptr);
       reflection->AddFloat(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_DOUBLE: {
-      GOOGLE_CHECK_GET_DOUBLE(item, value, NULL);
+      GOOGLE_CHECK_GET_DOUBLE(item, value, nullptr);
       reflection->AddDouble(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_BOOL: {
-      GOOGLE_CHECK_GET_BOOL(item, value, NULL);
+      GOOGLE_CHECK_GET_BOOL(item, value, nullptr);
       reflection->AddBool(message, field_descriptor, value);
       break;
     }
     case FieldDescriptor::CPPTYPE_STRING: {
-      if (!CheckAndSetString(
-          item, message, field_descriptor, reflection, true, -1)) {
-        return NULL;
+      if (!CheckAndSetString(item, message, field_descriptor, reflection, true,
+                             -1)) {
+        return nullptr;
       }
       break;
     }
     case FieldDescriptor::CPPTYPE_ENUM: {
-      GOOGLE_CHECK_GET_INT32(item, value, NULL);
+      GOOGLE_CHECK_GET_INT32(item, value, nullptr);
       if (reflection->SupportsUnknownEnumValues()) {
         reflection->AddEnumValue(message, field_descriptor, value);
       } else {
         const EnumDescriptor* enum_descriptor = field_descriptor->enum_type();
         const EnumValueDescriptor* enum_value =
             enum_descriptor->FindValueByNumber(value);
-        if (enum_value != NULL) {
+        if (enum_value != nullptr) {
           reflection->AddEnum(message, field_descriptor, enum_value);
         } else {
           ScopedPyObjectPtr s(PyObject_Str(item));
-          if (s != NULL) {
+          if (s != nullptr) {
             PyErr_Format(PyExc_ValueError, "Unknown enum value: %s",
                          PyString_AsString(s.get()));
           }
-          return NULL;
+          return nullptr;
         }
       }
       break;
     }
     default:
-      PyErr_Format(
-          PyExc_SystemError, "Adding value to a field of unknown type %d",
-          field_descriptor->cpp_type());
-      return NULL;
+      PyErr_Format(PyExc_SystemError,
+                   "Adding value to a field of unknown type %d",
+                   field_descriptor->cpp_type());
+      return nullptr;
   }
 
   Py_RETURN_NONE;
@@ -437,25 +433,24 @@ static int AssSubscript(PyObject* pself, PyObject* slice, PyObject* value) {
 
   cmessage::AssureWritable(self->parent);
   Message* message = self->parent->message;
-  const FieldDescriptor* field_descriptor =
-      self->parent_field_descriptor;
+  const FieldDescriptor* field_descriptor = self->parent_field_descriptor;
 
 #if PY_MAJOR_VERSION < 3
   if (PyInt_Check(slice)) {
     from = to = PyInt_AsLong(slice);
   } else  // NOLINT
 #endif
-  if (PyLong_Check(slice)) {
+      if (PyLong_Check(slice)) {
     from = to = PyLong_AsLong(slice);
   } else if (PySlice_Check(slice)) {
     const Reflection* reflection = message->GetReflection();
     length = reflection->FieldSize(*message, field_descriptor);
 #if PY_MAJOR_VERSION >= 3
-    if (PySlice_GetIndicesEx(slice,
-                             length, &from, &to, &step, &slicelength) == -1) {
+    if (PySlice_GetIndicesEx(slice, length, &from, &to, &step, &slicelength) ==
+        -1) {
 #else
-    if (PySlice_GetIndicesEx(reinterpret_cast<PySliceObject*>(slice),
-                             length, &from, &to, &step, &slicelength) == -1) {
+    if (PySlice_GetIndicesEx(reinterpret_cast<PySliceObject*>(slice), length,
+                             &from, &to, &step, &slicelength) == -1) {
 #endif
       return -1;
     }
@@ -465,7 +460,7 @@ static int AssSubscript(PyObject* pself, PyObject* slice, PyObject* value) {
     return -1;
   }
 
-  if (value == NULL) {
+  if (value == nullptr) {
     return cmessage::DeleteRepeatedField(self->parent, field_descriptor, slice);
   }
 
@@ -473,12 +468,12 @@ static int AssSubscript(PyObject* pself, PyObject* slice, PyObject* value) {
     return AssignItem(pself, from, value);
   }
 
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-  if (full_slice == NULL) {
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
     return -1;
   }
   ScopedPyObjectPtr new_list(Subscript(pself, full_slice.get()));
-  if (new_list == NULL) {
+  if (new_list == nullptr) {
     return -1;
   }
   if (PySequence_SetSlice(new_list.get(), from, to, value) < 0) {
@@ -495,23 +490,23 @@ PyObject* Extend(RepeatedScalarContainer* self, PyObject* value) {
   if (value == Py_None) {
     Py_RETURN_NONE;
   }
-  if ((Py_TYPE(value)->tp_as_sequence == NULL) && PyObject_Not(value)) {
+  if ((Py_TYPE(value)->tp_as_sequence == nullptr) && PyObject_Not(value)) {
     Py_RETURN_NONE;
   }
 
   ScopedPyObjectPtr iter(PyObject_GetIter(value));
-  if (iter == NULL) {
+  if (iter == nullptr) {
     PyErr_SetString(PyExc_TypeError, "Value must be iterable");
-    return NULL;
+    return nullptr;
   }
   ScopedPyObjectPtr next;
-  while ((next.reset(PyIter_Next(iter.get()))) != NULL) {
-    if (ScopedPyObjectPtr(Append(self, next.get())) == NULL) {
-      return NULL;
+  while ((next.reset(PyIter_Next(iter.get()))) != nullptr) {
+    if (ScopedPyObjectPtr(Append(self, next.get())) == nullptr) {
+      return nullptr;
     }
   }
   if (PyErr_Occurred()) {
-    return NULL;
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -523,16 +518,16 @@ static PyObject* Insert(PyObject* pself, PyObject* args) {
   Py_ssize_t index;
   PyObject* value;
   if (!PyArg_ParseTuple(args, "lO", &index, &value)) {
-    return NULL;
+    return nullptr;
   }
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
   ScopedPyObjectPtr new_list(Subscript(pself, full_slice.get()));
   if (PyList_Insert(new_list.get(), index, value) < 0) {
-    return NULL;
+    return nullptr;
   }
   int ret = InternalAssignRepeatedField(self, new_list.get());
   if (ret < 0) {
-    return NULL;
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -548,10 +543,10 @@ static PyObject* Remove(PyObject* pself, PyObject* value) {
   }
   if (match_index == -1) {
     PyErr_SetString(PyExc_ValueError, "remove(x): x not in container");
-    return NULL;
+    return nullptr;
   }
-  if (AssignItem(pself, match_index, NULL) < 0) {
-    return NULL;
+  if (AssignItem(pself, match_index, nullptr) < 0) {
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -570,9 +565,9 @@ static PyObject* RichCompare(PyObject* pself, PyObject* other, int opid) {
   // also a repeated scalar container, into Python lists so we can delegate
   // to the list's compare method.
 
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-  if (full_slice == NULL) {
-    return NULL;
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
+    return nullptr;
   }
 
   ScopedPyObjectPtr other_list_deleter;
@@ -582,54 +577,72 @@ static PyObject* RichCompare(PyObject* pself, PyObject* other, int opid) {
   }
 
   ScopedPyObjectPtr list(Subscript(pself, full_slice.get()));
-  if (list == NULL) {
-    return NULL;
+  if (list == nullptr) {
+    return nullptr;
   }
   return PyObject_RichCompare(list.get(), other, opid);
 }
 
 PyObject* Reduce(PyObject* unused_self, PyObject* unused_other) {
-  PyErr_Format(
-      PickleError_class,
-      "can't pickle repeated message fields, convert to list first");
-  return NULL;
+  PyErr_Format(PickleError_class,
+               "can't pickle repeated message fields, convert to list first");
+  return nullptr;
 }
 
 static PyObject* Sort(PyObject* pself, PyObject* args, PyObject* kwds) {
   // Support the old sort_function argument for backwards
   // compatibility.
-  if (kwds != NULL) {
+  if (kwds != nullptr) {
     PyObject* sort_func = PyDict_GetItemString(kwds, "sort_function");
-    if (sort_func != NULL) {
+    if (sort_func != nullptr) {
       // Must set before deleting as sort_func is a borrowed reference
       // and kwds might be the only thing keeping it alive.
-      if (PyDict_SetItemString(kwds, "cmp", sort_func) == -1)
-        return NULL;
-      if (PyDict_DelItemString(kwds, "sort_function") == -1)
-        return NULL;
+      if (PyDict_SetItemString(kwds, "cmp", sort_func) == -1) return nullptr;
+      if (PyDict_DelItemString(kwds, "sort_function") == -1) return nullptr;
     }
   }
 
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-  if (full_slice == NULL) {
-    return NULL;
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr list(Subscript(pself, full_slice.get()));
-  if (list == NULL) {
-    return NULL;
+  if (list == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr m(PyObject_GetAttrString(list.get(), "sort"));
-  if (m == NULL) {
-    return NULL;
+  if (m == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr res(PyObject_Call(m.get(), args, kwds));
-  if (res == NULL) {
-    return NULL;
+  if (res == nullptr) {
+    return nullptr;
+  }
+  int ret = InternalAssignRepeatedField(
+      reinterpret_cast<RepeatedScalarContainer*>(pself), list.get());
+  if (ret < 0) {
+    return nullptr;
+  }
+  Py_RETURN_NONE;
+}
+
+static PyObject* Reverse(PyObject* pself) {
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
+    return nullptr;
+  }
+  ScopedPyObjectPtr list(Subscript(pself, full_slice.get()));
+  if (list == nullptr) {
+    return nullptr;
+  }
+  ScopedPyObjectPtr res(PyObject_CallMethod(list.get(), "reverse", nullptr));
+  if (res == nullptr) {
+    return nullptr;
   }
   int ret = InternalAssignRepeatedField(
       reinterpret_cast<RepeatedScalarContainer*>(pself), list.get());
   if (ret < 0) {
-    return NULL;
+    return nullptr;
   }
   Py_RETURN_NONE;
 }
@@ -637,27 +650,27 @@ static PyObject* Sort(PyObject* pself, PyObject* args, PyObject* kwds) {
 static PyObject* Pop(PyObject* pself, PyObject* args) {
   Py_ssize_t index = -1;
   if (!PyArg_ParseTuple(args, "|n", &index)) {
-    return NULL;
+    return nullptr;
   }
   PyObject* item = Item(pself, index);
-  if (item == NULL) {
+  if (item == nullptr) {
     PyErr_Format(PyExc_IndexError, "list index (%zd) out of range", index);
-    return NULL;
+    return nullptr;
   }
-  if (AssignItem(pself, index, NULL) < 0) {
-    return NULL;
+  if (AssignItem(pself, index, nullptr) < 0) {
+    return nullptr;
   }
   return item;
 }
 
 static PyObject* ToStr(PyObject* pself) {
-  ScopedPyObjectPtr full_slice(PySlice_New(NULL, NULL, NULL));
-  if (full_slice == NULL) {
-    return NULL;
+  ScopedPyObjectPtr full_slice(PySlice_New(nullptr, nullptr, nullptr));
+  if (full_slice == nullptr) {
+    return nullptr;
   }
   ScopedPyObjectPtr list(Subscript(pself, full_slice.get()));
-  if (list == NULL) {
-    return NULL;
+  if (list == nullptr) {
+    return nullptr;
   }
   return PyObject_Repr(list.get());
 }
@@ -670,13 +683,13 @@ static PyObject* MergeFrom(PyObject* pself, PyObject* arg) {
 RepeatedScalarContainer* NewContainer(
     CMessage* parent, const FieldDescriptor* parent_field_descriptor) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
-    return NULL;
+    return nullptr;
   }
 
   RepeatedScalarContainer* self = reinterpret_cast<RepeatedScalarContainer*>(
       PyType_GenericAlloc(&RepeatedScalarContainer_Type, 0));
-  if (self == NULL) {
-    return NULL;
+  if (self == nullptr) {
+    return nullptr;
   }
 
   Py_INCREF(parent);
@@ -696,81 +709,81 @@ static void Dealloc(PyObject* pself) {
 }
 
 static PySequenceMethods SqMethods = {
-  Len,        /* sq_length */
-  0,          /* sq_concat */
-  0,          /* sq_repeat */
-  Item,       /* sq_item */
-  0,          /* sq_slice */
-  AssignItem  /* sq_ass_item */
+    Len,       /* sq_length */
+    nullptr,   /* sq_concat */
+    nullptr,   /* sq_repeat */
+    Item,      /* sq_item */
+    nullptr,   /* sq_slice */
+    AssignItem /* sq_ass_item */
 };
 
 static PyMappingMethods MpMethods = {
-  Len,               /* mp_length */
-  Subscript,      /* mp_subscript */
-  AssSubscript, /* mp_ass_subscript */
+    Len,          /* mp_length */
+    Subscript,    /* mp_subscript */
+    AssSubscript, /* mp_ass_subscript */
 };
 
 static PyMethodDef Methods[] = {
-  { "__deepcopy__", DeepCopy, METH_VARARGS,
-    "Makes a deep copy of the class." },
-  { "__reduce__", Reduce, METH_NOARGS,
-    "Outputs picklable representation of the repeated field." },
-  { "append", AppendMethod, METH_O,
-    "Appends an object to the repeated container." },
-  { "extend", ExtendMethod, METH_O,
-    "Appends objects to the repeated container." },
-  { "insert", Insert, METH_VARARGS,
-    "Inserts an object at the specified position in the container." },
-  { "pop", Pop, METH_VARARGS,
-    "Removes an object from the repeated container and returns it." },
-  { "remove", Remove, METH_O,
-    "Removes an object from the repeated container." },
-  { "sort", (PyCFunction)Sort, METH_VARARGS | METH_KEYWORDS,
-    "Sorts the repeated container."},
-  { "MergeFrom", (PyCFunction)MergeFrom, METH_O,
-    "Merges a repeated container into the current container." },
-  { NULL, NULL }
-};
+    {"__deepcopy__", DeepCopy, METH_VARARGS, "Makes a deep copy of the class."},
+    {"__reduce__", Reduce, METH_NOARGS,
+     "Outputs picklable representation of the repeated field."},
+    {"append", AppendMethod, METH_O,
+     "Appends an object to the repeated container."},
+    {"extend", ExtendMethod, METH_O,
+     "Appends objects to the repeated container."},
+    {"insert", Insert, METH_VARARGS,
+     "Inserts an object at the specified position in the container."},
+    {"pop", Pop, METH_VARARGS,
+     "Removes an object from the repeated container and returns it."},
+    {"remove", Remove, METH_O,
+     "Removes an object from the repeated container."},
+    {"sort", reinterpret_cast<PyCFunction>(Sort), METH_VARARGS | METH_KEYWORDS,
+     "Sorts the repeated container."},
+    {"reverse", reinterpret_cast<PyCFunction>(Reverse), METH_NOARGS,
+     "Reverses elements order of the repeated container."},
+    {"MergeFrom", static_cast<PyCFunction>(MergeFrom), METH_O,
+     "Merges a repeated container into the current container."},
+    {nullptr, nullptr}};
 
 }  // namespace repeated_scalar_container
 
 PyTypeObject RepeatedScalarContainer_Type = {
-  PyVarObject_HEAD_INIT(&PyType_Type, 0)
-  FULL_MODULE_NAME ".RepeatedScalarContainer",  // tp_name
-  sizeof(RepeatedScalarContainer),     // tp_basicsize
-  0,                                   //  tp_itemsize
-  repeated_scalar_container::Dealloc,  //  tp_dealloc
-  0,                                   //  tp_print
-  0,                                   //  tp_getattr
-  0,                                   //  tp_setattr
-  0,                                   //  tp_compare
-  repeated_scalar_container::ToStr,    //  tp_repr
-  0,                                   //  tp_as_number
-  &repeated_scalar_container::SqMethods,   //  tp_as_sequence
-  &repeated_scalar_container::MpMethods,   //  tp_as_mapping
-  PyObject_HashNotImplemented,         //  tp_hash
-  0,                                   //  tp_call
-  0,                                   //  tp_str
-  0,                                   //  tp_getattro
-  0,                                   //  tp_setattro
-  0,                                   //  tp_as_buffer
-  Py_TPFLAGS_DEFAULT,                  //  tp_flags
-  "A Repeated scalar container",       //  tp_doc
-  0,                                   //  tp_traverse
-  0,                                   //  tp_clear
-  repeated_scalar_container::RichCompare,  //  tp_richcompare
-  0,                                   //  tp_weaklistoffset
-  0,                                   //  tp_iter
-  0,                                   //  tp_iternext
-  repeated_scalar_container::Methods,      //  tp_methods
-  0,                                   //  tp_members
-  0,                                   //  tp_getset
-  0,                                   //  tp_base
-  0,                                   //  tp_dict
-  0,                                   //  tp_descr_get
-  0,                                   //  tp_descr_set
-  0,                                   //  tp_dictoffset
-  0,                                   //  tp_init
+    PyVarObject_HEAD_INIT(&PyType_Type, 0) FULL_MODULE_NAME
+    ".RepeatedScalarContainer",              // tp_name
+    sizeof(RepeatedScalarContainer),         // tp_basicsize
+    0,                                       //  tp_itemsize
+    repeated_scalar_container::Dealloc,      //  tp_dealloc
+    nullptr,                                 //  tp_print
+    nullptr,                                 //  tp_getattr
+    nullptr,                                 //  tp_setattr
+    nullptr,                                 //  tp_compare
+    repeated_scalar_container::ToStr,        //  tp_repr
+    nullptr,                                 //  tp_as_number
+    &repeated_scalar_container::SqMethods,   //  tp_as_sequence
+    &repeated_scalar_container::MpMethods,   //  tp_as_mapping
+    PyObject_HashNotImplemented,             //  tp_hash
+    nullptr,                                 //  tp_call
+    nullptr,                                 //  tp_str
+    nullptr,                                 //  tp_getattro
+    nullptr,                                 //  tp_setattro
+    nullptr,                                 //  tp_as_buffer
+    Py_TPFLAGS_DEFAULT,                      //  tp_flags
+    "A Repeated scalar container",           //  tp_doc
+    nullptr,                                 //  tp_traverse
+    nullptr,                                 //  tp_clear
+    repeated_scalar_container::RichCompare,  //  tp_richcompare
+    0,                                       //  tp_weaklistoffset
+    nullptr,                                 //  tp_iter
+    nullptr,                                 //  tp_iternext
+    repeated_scalar_container::Methods,      //  tp_methods
+    nullptr,                                 //  tp_members
+    nullptr,                                 //  tp_getset
+    nullptr,                                 //  tp_base
+    nullptr,                                 //  tp_dict
+    nullptr,                                 //  tp_descr_get
+    nullptr,                                 //  tp_descr_set
+    0,                                       //  tp_dictoffset
+    nullptr,                                 //  tp_init
 };
 
 }  // namespace python

python/setup.py

@@ -254,7 +254,7 @@ if __name__ == '__main__':
     os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'cpp'
 
   # Keep this list of dependencies in sync with tox.ini.
-  install_requires = ['six>=1.9']
+  install_requires = ['six>=1.9', 'setuptools']
   if sys.version_info <= (2,7):
     install_requires.append('ordereddict')
     install_requires.append('unittest2')

src/google/protobuf/any.cc

@@ -41,17 +41,17 @@ namespace google {
 namespace protobuf {
 namespace internal {
 
-void AnyMetadata::PackFrom(const Message& message) {
-  PackFrom(message, kTypeGoogleApisComPrefix);
+bool AnyMetadata::PackFrom(const Message& message) {
+  return PackFrom(message, kTypeGoogleApisComPrefix);
 }
 
-void AnyMetadata::PackFrom(const Message& message,
+bool AnyMetadata::PackFrom(const Message& message,
                            StringPiece type_url_prefix) {
   type_url_->Set(
       &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyString(),
       GetTypeUrl(message.GetDescriptor()->full_name(), type_url_prefix),
       nullptr);
-  message.SerializeToString(
+  return message.SerializeToString(
       value_->Mutable(ArenaStringPtr::EmptyDefault{}, nullptr));
 }
 
@@ -80,3 +80,5 @@ bool GetAnyFieldDescriptors(const Message& message,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/any.h

@@ -65,12 +65,14 @@ class PROTOBUF_EXPORT AnyMetadata {
 
   // Packs a message using the default type URL prefix: "type.googleapis.com".
   // The resulted type URL will be "type.googleapis.com/<message_full_name>".
+  // Returns false if serializing the message failed.
   template <typename T>
-  void PackFrom(const T& message) {
-    InternalPackFrom(message, kTypeGoogleApisComPrefix, T::FullMessageName());
+  bool PackFrom(const T& message) {
+    return InternalPackFrom(message, kTypeGoogleApisComPrefix,
+                            T::FullMessageName());
   }
 
-  void PackFrom(const Message& message);
+  bool PackFrom(const Message& message);
 
   // Packs a message using the given type URL prefix. The type URL will be
   // constructed by concatenating the message type's full name to the prefix
@@ -78,12 +80,13 @@ class PROTOBUF_EXPORT AnyMetadata {
   // For example, both PackFrom(message, "type.googleapis.com") and
   // PackFrom(message, "type.googleapis.com/") yield the same result type
   // URL: "type.googleapis.com/<message_full_name>".
+  // Returns false if serializing the message failed.
   template <typename T>
-  void PackFrom(const T& message, StringPiece type_url_prefix) {
-    InternalPackFrom(message, type_url_prefix, T::FullMessageName());
+  bool PackFrom(const T& message, StringPiece type_url_prefix) {
+    return InternalPackFrom(message, type_url_prefix, T::FullMessageName());
   }
 
-  void PackFrom(const Message& message, StringPiece type_url_prefix);
+  bool PackFrom(const Message& message, StringPiece type_url_prefix);
 
   // Unpacks the payload into the given message. Returns false if the message's
   // type doesn't match the type specified in the type URL (i.e., the full
@@ -105,7 +108,7 @@ class PROTOBUF_EXPORT AnyMetadata {
   }
 
  private:
-  void InternalPackFrom(const MessageLite& message,
+  bool InternalPackFrom(const MessageLite& message,
                         StringPiece type_url_prefix,
                         StringPiece type_name);
   bool InternalUnpackTo(StringPiece type_name,

src/google/protobuf/any.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class AnyDefaultTypeInternal {
  public:
@@ -76,7 +78,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fany_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fany_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fany_2eproto(&descriptor_table_google_2fprotobuf_2fany_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/any.pb.h

@@ -110,12 +110,12 @@ class PROTOBUF_EXPORT Any PROTOBUF_FINAL :
 
   // implements Any -----------------------------------------------
 
-  void PackFrom(const ::PROTOBUF_NAMESPACE_ID::Message& message) {
-    _any_metadata_.PackFrom(message);
+  bool PackFrom(const ::PROTOBUF_NAMESPACE_ID::Message& message) {
+    return _any_metadata_.PackFrom(message);
   }
-  void PackFrom(const ::PROTOBUF_NAMESPACE_ID::Message& message,
+  bool PackFrom(const ::PROTOBUF_NAMESPACE_ID::Message& message,
                 ::PROTOBUF_NAMESPACE_ID::ConstStringParam type_url_prefix) {
-    _any_metadata_.PackFrom(message, type_url_prefix);
+    return _any_metadata_.PackFrom(message, type_url_prefix);
   }
   bool UnpackTo(::PROTOBUF_NAMESPACE_ID::Message* message) const {
     return _any_metadata_.UnpackTo(message);
@@ -125,13 +125,13 @@ class PROTOBUF_EXPORT Any PROTOBUF_FINAL :
       const ::PROTOBUF_NAMESPACE_ID::FieldDescriptor** type_url_field,
       const ::PROTOBUF_NAMESPACE_ID::FieldDescriptor** value_field);
   template <typename T, class = typename std::enable_if<!std::is_convertible<T, const ::PROTOBUF_NAMESPACE_ID::Message&>::value>::type>
-  void PackFrom(const T& message) {
-    _any_metadata_.PackFrom<T>(message);
+  bool PackFrom(const T& message) {
+    return _any_metadata_.PackFrom<T>(message);
   }
   template <typename T, class = typename std::enable_if<!std::is_convertible<T, const ::PROTOBUF_NAMESPACE_ID::Message&>::value>::type>
-  void PackFrom(const T& message,
+  bool PackFrom(const T& message,
                 ::PROTOBUF_NAMESPACE_ID::ConstStringParam type_url_prefix) {
-    _any_metadata_.PackFrom<T>(message, type_url_prefix);}
+    return _any_metadata_.PackFrom<T>(message, type_url_prefix);}
   template <typename T, class = typename std::enable_if<!std::is_convertible<T, const ::PROTOBUF_NAMESPACE_ID::Message&>::value>::type>
   bool UnpackTo(T* message) const {
     return _any_metadata_.UnpackTo<T>(message);

src/google/protobuf/any_lite.cc

@@ -53,12 +53,12 @@ const char kAnyFullTypeName[] = "google.protobuf.Any";
 const char kTypeGoogleApisComPrefix[] = "type.googleapis.com/";
 const char kTypeGoogleProdComPrefix[] = "type.googleprod.com/";
 
-void AnyMetadata::InternalPackFrom(const MessageLite& message,
+bool AnyMetadata::InternalPackFrom(const MessageLite& message,
                                    StringPiece type_url_prefix,
                                    StringPiece type_name) {
   type_url_->Set(&::google::protobuf::internal::GetEmptyString(),
                  GetTypeUrl(type_name, type_url_prefix), nullptr);
-  message.SerializeToString(
+  return message.SerializeToString(
       value_->Mutable(ArenaStringPtr::EmptyDefault{}, nullptr));
 }
 

src/google/protobuf/any_test.cc

@@ -49,7 +49,7 @@ TEST(AnyTest, TestPackAndUnpack) {
   protobuf_unittest::TestAny submessage;
   submessage.set_int32_value(12345);
   protobuf_unittest::TestAny message;
-  message.mutable_any_value()->PackFrom(submessage);
+  ASSERT_TRUE(message.mutable_any_value()->PackFrom(submessage));
 
   std::string data = message.SerializeAsString();
 
@@ -60,6 +60,13 @@ TEST(AnyTest, TestPackAndUnpack) {
   EXPECT_EQ(12345, submessage.int32_value());
 }
 
+TEST(AnyTest, TestPackFromSerializationExceedsSizeLimit) {
+  protobuf_unittest::TestAny submessage;
+  submessage.mutable_text()->resize(INT_MAX, 'a');
+  protobuf_unittest::TestAny message;
+  EXPECT_FALSE(message.mutable_any_value()->PackFrom(submessage));
+}
+
 TEST(AnyTest, TestUnpackWithTypeMismatch) {
   protobuf_unittest::TestAny payload;
   payload.set_int32_value(13);
@@ -173,3 +180,5 @@ TEST(AnyTest, MoveAssignment) {
 }  // namespace
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/any_test.proto

@@ -34,8 +34,11 @@ package protobuf_unittest;
 
 import "google/protobuf/any.proto";
 
+option java_outer_classname = "TestAnyProto";
+
 message TestAny {
   int32 int32_value = 1;
   google.protobuf.Any any_value = 2;
   repeated google.protobuf.Any repeated_any_value = 3;
+  string text = 4;
 }

src/google/protobuf/api.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fapi_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_Method_google_2fprotobuf_2fapi_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fapi_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<0> scc_info_Mixin_google_2fprotobuf_2fapi_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2ftype_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_Option_google_2fprotobuf_2ftype_2eproto;
@@ -164,7 +166,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fapi_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fapi_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fapi_2eproto(&descriptor_table_google_2fprotobuf_2fapi_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/arena.cc

@@ -32,10 +32,14 @@
 
 #include <algorithm>
 #include <atomic>
+#include <cstddef>
+#include <cstdint>
 #include <limits>
+#include <typeinfo>
 
-#include <google/protobuf/stubs/mutex.h>
+#include <google/protobuf/arena_impl.h>
 
+#include <google/protobuf/stubs/mutex.h>
 #ifdef ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // ADDRESS_SANITIZER
@@ -47,370 +51,388 @@ static const size_t kMaxCleanupListElements = 64;  // 1kB on 64-bit.
 
 namespace google {
 namespace protobuf {
+namespace internal {
 
-PROTOBUF_EXPORT /*static*/ void* (*const ArenaOptions::kDefaultBlockAlloc)(
-    size_t) = &::operator new;
+static SerialArena::Memory AllocateMemory(const AllocationPolicy* policy_ptr,
+                                          size_t last_size, size_t min_bytes) {
+  AllocationPolicy policy;  // default policy
+  if (policy_ptr) policy = *policy_ptr;
+  size_t size;
+  if (last_size != 0) {
+    // Double the current block size, up to a limit.
+    auto max_size = policy.max_block_size;
+    size = std::min(2 * last_size, max_size);
+  } else {
+    size = policy.start_block_size;
+  }
+  // Verify that min_bytes + kBlockHeaderSize won't overflow.
+  GOOGLE_CHECK_LE(min_bytes,
+           std::numeric_limits<size_t>::max() - SerialArena::kBlockHeaderSize);
+  size = std::max(size, SerialArena::kBlockHeaderSize + min_bytes);
 
-namespace internal {
+  void* mem;
+  if (policy.block_alloc == nullptr) {
+    mem = ::operator new(size);
+  } else {
+    mem = policy.block_alloc(size);
+  }
+  return {mem, size};
+}
+
+class GetDeallocator {
+ public:
+  GetDeallocator(const AllocationPolicy* policy, size_t* space_allocated)
+      : dealloc_(policy ? policy->block_dealloc : nullptr),
+        space_allocated_(space_allocated) {}
+
+  void operator()(SerialArena::Memory mem) const {
+#ifdef ADDRESS_SANITIZER
+    // This memory was provided by the underlying allocator as unpoisoned,
+    // so return it in an unpoisoned state.
+    ASAN_UNPOISON_MEMORY_REGION(mem.ptr, mem.size);
+#endif  // ADDRESS_SANITIZER
+    if (dealloc_) {
+      dealloc_(mem.ptr, mem.size);
+    } else {
+#if defined(__GXX_DELETE_WITH_SIZE__) || defined(__cpp_sized_deallocation)
+      ::operator delete(mem.ptr, mem.size);
+#else
+      ::operator delete(mem.ptr);
+#endif
+    }
+    *space_allocated_ += mem.size;
+  }
+
+ private:
+  void (*dealloc_)(void*, size_t);
+  size_t* space_allocated_;
+};
+
+SerialArena::SerialArena(Block* b, void* owner) : space_allocated_(b->size) {
+  owner_ = owner;
+  head_ = b;
+  ptr_ = b->Pointer(kBlockHeaderSize + ThreadSafeArena::kSerialArenaSize);
+  limit_ = b->Pointer(b->size & static_cast<size_t>(-8));
+}
+
+SerialArena* SerialArena::New(Memory mem, void* owner) {
+  GOOGLE_DCHECK_LE(kBlockHeaderSize + ThreadSafeArena::kSerialArenaSize, mem.size);
+
+  auto b = new (mem.ptr) Block{nullptr, mem.size};
+  return new (b->Pointer(kBlockHeaderSize)) SerialArena(b, owner);
+}
+
+template <typename Deallocator>
+SerialArena::Memory SerialArena::Free(Deallocator deallocator) {
+  Block* b = head_;
+  Memory mem = {b, b->size};
+  while (b->next) {
+    b = b->next;  // We must first advance before deleting this block
+    deallocator(mem);
+    mem = {b, b->size};
+  }
+  return mem;
+}
+
+PROTOBUF_NOINLINE
+std::pair<void*, SerialArena::CleanupNode*>
+SerialArena::AllocateAlignedWithCleanupFallback(
+    size_t n, const AllocationPolicy* policy) {
+  AllocateNewBlock(n + kCleanupSize, policy);
+  return AllocateAlignedWithCleanup(n, policy);
+}
+
+PROTOBUF_NOINLINE
+void* SerialArena::AllocateAlignedFallback(size_t n,
+                                           const AllocationPolicy* policy) {
+  AllocateNewBlock(n, policy);
+  return AllocateAligned(n, policy);
+}
+
+void SerialArena::AllocateNewBlock(size_t n, const AllocationPolicy* policy) {
+  // Sync limit to block
+  head_->start = reinterpret_cast<CleanupNode*>(limit_);
+
+  // Record how much used in this block.
+  space_used_ += ptr_ - head_->Pointer(kBlockHeaderSize);
+
+  auto mem = AllocateMemory(policy, head_->size, n);
+  // We don't want to emit an expensive RMW instruction that requires
+  // exclusive access to a cacheline. Hence we write it in terms of a
+  // regular add.
+  auto relaxed = std::memory_order_relaxed;
+  space_allocated_.store(space_allocated_.load(relaxed) + mem.size, relaxed);
+  head_ = new (mem.ptr) Block{head_, mem.size};
+  ptr_ = head_->Pointer(kBlockHeaderSize);
+  limit_ = head_->Pointer(head_->size);
+
+#ifdef ADDRESS_SANITIZER
+  ASAN_POISON_MEMORY_REGION(ptr_, limit_ - ptr_);
+#endif  // ADDRESS_SANITIZER
+}
+
+uint64 SerialArena::SpaceUsed() const {
+  uint64 space_used = ptr_ - head_->Pointer(kBlockHeaderSize);
+  space_used += space_used_;
+  // Remove the overhead of the SerialArena itself.
+  space_used -= ThreadSafeArena::kSerialArenaSize;
+  return space_used;
+}
 
+void SerialArena::CleanupList() {
+  Block* b = head_;
+  b->start = reinterpret_cast<CleanupNode*>(limit_);
+  do {
+    auto* limit = reinterpret_cast<CleanupNode*>(
+        b->Pointer(b->size & static_cast<size_t>(-8)));
+    auto it = b->start;
+    auto num = limit - it;
+    if (num > 0) {
+      for (; it < limit; it++) {
+        it->cleanup(it->elem);
+      }
+    }
+    b = b->next;
+  } while (b);
+}
 
-ArenaImpl::CacheAlignedLifecycleIdGenerator ArenaImpl::lifecycle_id_generator_;
+
+ThreadSafeArena::CacheAlignedLifecycleIdGenerator
+    ThreadSafeArena::lifecycle_id_generator_;
 #if defined(GOOGLE_PROTOBUF_NO_THREADLOCAL)
-ArenaImpl::ThreadCache& ArenaImpl::thread_cache() {
+ThreadSafeArena::ThreadCache& ThreadSafeArena::thread_cache() {
   static internal::ThreadLocalStorage<ThreadCache>* thread_cache_ =
       new internal::ThreadLocalStorage<ThreadCache>();
   return *thread_cache_->Get();
 }
 #elif defined(PROTOBUF_USE_DLLS)
-ArenaImpl::ThreadCache& ArenaImpl::thread_cache() {
+ThreadSafeArena::ThreadCache& ThreadSafeArena::thread_cache() {
   static PROTOBUF_THREAD_LOCAL ThreadCache thread_cache_ = {
       0, static_cast<LifecycleIdAtomic>(-1), nullptr};
   return thread_cache_;
 }
 #else
-PROTOBUF_THREAD_LOCAL ArenaImpl::ThreadCache ArenaImpl::thread_cache_ = {
-    0, static_cast<LifecycleIdAtomic>(-1), nullptr};
+PROTOBUF_THREAD_LOCAL ThreadSafeArena::ThreadCache
+    ThreadSafeArena::thread_cache_ = {0, static_cast<LifecycleIdAtomic>(-1),
+                                      nullptr};
 #endif
 
-void ArenaFree(void* object, size_t size) {
-#if defined(__GXX_DELETE_WITH_SIZE__) || defined(__cpp_sized_deallocation)
-  ::operator delete(object, size);
-#else
-  (void)size;
-  ::operator delete(object);
-#endif
-}
-
-ArenaImpl::ArenaImpl(const ArenaOptions& options) {
-  ArenaMetricsCollector* collector = nullptr;
-  bool record_allocs = false;
-  if (options.make_metrics_collector != nullptr) {
-    collector = (*options.make_metrics_collector)();
-    record_allocs = (collector && collector->RecordAllocs());
-  }
+void ThreadSafeArena::InitializeFrom(void* mem, size_t size) {
+  GOOGLE_DCHECK_EQ(reinterpret_cast<uintptr_t>(mem) & 7, 0u);
+  Init(false);
 
-  // Get memory where we can store non-default options if needed.
-  // Use supplied initial_block if it is large enough.
-  size_t min_block_size = kOptionsSize + kBlockHeaderSize + kSerialArenaSize;
-  char* mem = options.initial_block;
-  size_t mem_size = options.initial_block_size;
-  GOOGLE_DCHECK_EQ(reinterpret_cast<uintptr_t>(mem) & 7, 0);
-  if (mem == nullptr || mem_size < min_block_size) {
-    // Supplied initial block is not big enough.
-    mem_size = std::max(min_block_size, options.start_block_size);
-    mem = reinterpret_cast<char*>((*options.block_alloc)(mem_size));
+  // Ignore initial block if it is too small.
+  if (mem != nullptr && size >= kBlockHeaderSize + kSerialArenaSize) {
+    alloc_policy_ |= kUserOwnedInitialBlock;
+    SetInitialBlock(mem, size);
   }
+}
 
-  // Create the special block.
-  const bool special = true;
-  const bool user_owned = (mem == options.initial_block);
-  auto block =
-      new (mem) SerialArena::Block(mem_size, nullptr, special, user_owned);
-
-  // Options occupy the beginning of the initial block.
-  options_ = new (block->Pointer(block->pos())) Options;
-#ifdef ADDRESS_SANITIZER
-  ASAN_UNPOISON_MEMORY_REGION(options_, kOptionsSize);
-#endif  // ADDRESS_SANITIZER
-  options_->start_block_size = options.start_block_size;
-  options_->max_block_size = options.max_block_size;
-  options_->block_alloc = options.block_alloc;
-  options_->block_dealloc = options.block_dealloc;
-  options_->metrics_collector = collector;
-  block->set_pos(block->pos() + kOptionsSize);
+void ThreadSafeArena::InitializeWithPolicy(void* mem, size_t size,
+                                           bool record_allocs,
+                                           AllocationPolicy policy) {
+  GOOGLE_DCHECK_EQ(reinterpret_cast<uintptr_t>(mem) & 7, 0u);
 
   Init(record_allocs);
-  SetInitialBlock(block);
+
+  // Ignore initial block if it is too small. We include an optional
+  // AllocationPolicy in this check, so that this can be allocated on the
+  // first block.
+  constexpr size_t kAPSize = internal::AlignUpTo8(sizeof(AllocationPolicy));
+  constexpr size_t kMinimumSize = kBlockHeaderSize + kSerialArenaSize + kAPSize;
+  if (mem != nullptr && size >= kMinimumSize) {
+    alloc_policy_ = kUserOwnedInitialBlock;
+  } else {
+    alloc_policy_ = 0;
+    auto tmp = AllocateMemory(&policy, 0, kMinimumSize);
+    mem = tmp.ptr;
+    size = tmp.size;
+  }
+  SetInitialBlock(mem, size);
+
+  auto sa = threads_.load(std::memory_order_relaxed);
+  // We ensured enough space so this cannot fail.
+  void* p;
+  if (!sa || !sa->MaybeAllocateAligned(kAPSize, &p)) {
+    GOOGLE_LOG(FATAL) << "MaybeAllocateAligned cannot fail here.";
+    return;
+  }
+  new (p) AllocationPolicy{policy};
+  alloc_policy_ |= reinterpret_cast<intptr_t>(p);
 }
 
-void ArenaImpl::Init(bool record_allocs) {
+void ThreadSafeArena::Init(bool record_allocs) {
   ThreadCache& tc = thread_cache();
   auto id = tc.next_lifecycle_id;
-  constexpr uint64 kInc = ThreadCache::kPerThreadIds * 2;
+  // We increment lifecycle_id's by multiples of two so we can use bit 0 as
+  // a tag.
+  constexpr uint64 kDelta = 2;
+  constexpr uint64 kInc = ThreadCache::kPerThreadIds * kDelta;
   if (PROTOBUF_PREDICT_FALSE((id & (kInc - 1)) == 0)) {
-    if (sizeof(lifecycle_id_generator_.id) == 4) {
-      // 2^32 is dangerous low to guarantee uniqueness. If we start dolling out
-      // unique id's in ranges of kInc it's unacceptably low. In this case
-      // we increment by 1. The additional range of kPerThreadIds that are used
-      // per thread effectively pushes the overflow time from weeks to years
-      // of continuous running.
-      id = lifecycle_id_generator_.id.fetch_add(1, std::memory_order_relaxed) *
-           kInc;
-    } else {
-      id =
-          lifecycle_id_generator_.id.fetch_add(kInc, std::memory_order_relaxed);
-    }
+    constexpr auto relaxed = std::memory_order_relaxed;
+    // On platforms that don't support uint64 atomics we can certainly not
+    // afford to increment by large intervals and expect uniqueness due to
+    // wrapping, hence we only add by 1.
+    id = lifecycle_id_generator_.id.fetch_add(1, relaxed) * kInc;
   }
-  tc.next_lifecycle_id = id + 2;
-  // We store "record_allocs" in the low bit of lifecycle_id_.
-  lifecycle_id_ = id | (record_allocs ? 1 : 0);
+  tc.next_lifecycle_id = id + kDelta;
+  tag_and_id_ = id | (record_allocs ? kRecordAllocs : 0);
   hint_.store(nullptr, std::memory_order_relaxed);
   threads_.store(nullptr, std::memory_order_relaxed);
-  space_allocated_.store(0, std::memory_order_relaxed);
 }
 
-void ArenaImpl::SetInitialBlock(SerialArena::Block* block) {
-  // Calling thread owns the first block. This allows the single-threaded case
-  // to allocate on the first block without having to perform atomic operations.
-  SerialArena* serial = SerialArena::New(block, &thread_cache(), this);
+void ThreadSafeArena::SetInitialBlock(void* mem, size_t size) {
+  SerialArena* serial = SerialArena::New({mem, size}, &thread_cache());
   serial->set_next(NULL);
   threads_.store(serial, std::memory_order_relaxed);
-  space_allocated_.store(block->size(), std::memory_order_relaxed);
   CacheSerialArena(serial);
 }
 
-ArenaImpl::~ArenaImpl() {
+ThreadSafeArena::~ThreadSafeArena() {
   // Have to do this in a first pass, because some of the destructors might
   // refer to memory in other blocks.
   CleanupList();
 
-  ArenaMetricsCollector* collector = nullptr;
-  auto deallocator = &ArenaFree;
-  if (options_) {
-    collector = options_->metrics_collector;
-    deallocator = options_->block_dealloc;
-  }
+  size_t space_allocated = 0;
+  auto mem = Free(&space_allocated);
 
-  PerBlock([deallocator](SerialArena::Block* b) {
-#ifdef ADDRESS_SANITIZER
-    // This memory was provided by the underlying allocator as unpoisoned, so
-    // return it in an unpoisoned state.
-    ASAN_UNPOISON_MEMORY_REGION(b->Pointer(0), b->size());
-#endif  // ADDRESS_SANITIZER
-    if (!b->user_owned()) {
-      (*deallocator)(b, b->size());
-    }
-  });
+  // Policy is about to get deleted.
+  auto p = AllocPolicy();
+  ArenaMetricsCollector* collector = p ? p->metrics_collector : nullptr;
 
-  if (collector) {
-    collector->OnDestroy(SpaceAllocated());
+  if (alloc_policy_ & kUserOwnedInitialBlock) {
+    space_allocated += mem.size;
+  } else {
+    GetDeallocator(AllocPolicy(), &space_allocated)(mem);
   }
+
+  if (collector) collector->OnDestroy(space_allocated);
 }
 
-uint64 ArenaImpl::Reset() {
-  if (options_ && options_->metrics_collector) {
-    options_->metrics_collector->OnReset(SpaceAllocated());
-  }
+SerialArena::Memory ThreadSafeArena::Free(size_t* space_allocated) {
+  SerialArena::Memory mem = {nullptr, 0};
+  auto deallocator = GetDeallocator(AllocPolicy(), space_allocated);
+  PerSerialArena([deallocator, &mem](SerialArena* a) {
+    if (mem.ptr) deallocator(mem);
+    mem = a->Free(deallocator);
+  });
+  return mem;
+}
 
+uint64 ThreadSafeArena::Reset() {
   // Have to do this in a first pass, because some of the destructors might
   // refer to memory in other blocks.
   CleanupList();
 
   // Discard all blocks except the special block (if present).
-  uint64 space_allocated = 0;
-  SerialArena::Block* special_block = nullptr;
-  auto deallocator = (options_ ? options_->block_dealloc : &ArenaFree);
-  PerBlock(
-      [&space_allocated, &special_block, deallocator](SerialArena::Block* b) {
-        space_allocated += b->size();
-#ifdef ADDRESS_SANITIZER
-        // This memory was provided by the underlying allocator as unpoisoned,
-        // so return it in an unpoisoned state.
-        ASAN_UNPOISON_MEMORY_REGION(b->Pointer(0), b->size());
-#endif  // ADDRESS_SANITIZER
-        if (!b->special()) {
-          (*deallocator)(b, b->size());
-        } else {
-          // Prepare special block for reuse.
-          // Note: if options_ is present, it occupies the beginning of the
-          // block and therefore pos is advanced past it.
-          GOOGLE_DCHECK(special_block == nullptr);
-          special_block = b;
-        }
-      });
-
-  Init(record_allocs());
-  if (special_block != nullptr) {
-    // next() should still be nullptr since we are using a stack discipline, but
-    // clear it anyway to reduce fragility.
-    GOOGLE_DCHECK_EQ(special_block->next(), nullptr);
-    special_block->clear_next();
-    special_block->set_pos(kBlockHeaderSize + (options_ ? kOptionsSize : 0));
-    SetInitialBlock(special_block);
-  }
-  return space_allocated;
-}
+  size_t space_allocated = 0;
+  auto mem = Free(&space_allocated);
 
-std::pair<void*, size_t> ArenaImpl::NewBuffer(size_t last_size,
-                                              size_t min_bytes) {
-  size_t size;
-  if (last_size != -1) {
-    // Double the current block size, up to a limit.
-    auto max_size = options_ ? options_->max_block_size : kDefaultMaxBlockSize;
-    size = std::min(2 * last_size, max_size);
+  if (AllocPolicy()) {
+    auto saved_policy = *AllocPolicy();
+    if (alloc_policy_ & kUserOwnedInitialBlock) {
+      space_allocated += mem.size;
+    } else {
+      GetDeallocator(AllocPolicy(), &space_allocated)(mem);
+      mem.ptr = nullptr;
+      mem.size = 0;
+    }
+    ArenaMetricsCollector* collector = saved_policy.metrics_collector;
+    if (collector) collector->OnReset(space_allocated);
+    InitializeWithPolicy(mem.ptr, mem.size, ShouldRecordAlloc(), saved_policy);
   } else {
-    size = options_ ? options_->start_block_size : kDefaultStartBlockSize;
+    // Nullptr policy
+    if (alloc_policy_ & kUserOwnedInitialBlock) {
+      space_allocated += mem.size;
+      InitializeFrom(mem.ptr, mem.size);
+    } else {
+      GetDeallocator(AllocPolicy(), &space_allocated)(mem);
+      Init(false);
+    }
   }
-  // Verify that min_bytes + kBlockHeaderSize won't overflow.
-  GOOGLE_CHECK_LE(min_bytes, std::numeric_limits<size_t>::max() - kBlockHeaderSize);
-  size = std::max(size, kBlockHeaderSize + min_bytes);
 
-  void* mem = options_ ? (*options_->block_alloc)(size) : ::operator new(size);
-  space_allocated_.fetch_add(size, std::memory_order_relaxed);
-  return {mem, size};
-}
-
-SerialArena::Block* SerialArena::NewBlock(SerialArena::Block* last_block,
-                                          size_t min_bytes, ArenaImpl* arena) {
-  void* mem;
-  size_t size;
-  std::tie(mem, size) =
-      arena->NewBuffer(last_block ? last_block->size() : -1, min_bytes);
-  Block* b = new (mem) Block(size, last_block, false, false);
-  return b;
-}
-
-PROTOBUF_NOINLINE
-void SerialArena::AddCleanupFallback(void* elem, void (*cleanup)(void*)) {
-  size_t size = cleanup_ ? cleanup_->size * 2 : kMinCleanupListElements;
-  size = std::min(size, kMaxCleanupListElements);
-  size_t bytes = internal::AlignUpTo8(CleanupChunk::SizeOf(size));
-  CleanupChunk* list = reinterpret_cast<CleanupChunk*>(AllocateAligned(bytes));
-  list->next = cleanup_;
-  list->size = size;
-
-  cleanup_ = list;
-  cleanup_ptr_ = &list->nodes[0];
-  cleanup_limit_ = &list->nodes[size];
-
-  AddCleanup(elem, cleanup);
+  return space_allocated;
 }
 
-void* ArenaImpl::AllocateAlignedAndAddCleanup(size_t n,
-                                              void (*cleanup)(void*)) {
+std::pair<void*, SerialArena::CleanupNode*>
+ThreadSafeArena::AllocateAlignedWithCleanup(size_t n,
+                                            const std::type_info* type) {
   SerialArena* arena;
-  if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(&arena))) {
-    return arena->AllocateAlignedAndAddCleanup(n, cleanup);
+  if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(tag_and_id_, &arena))) {
+    return arena->AllocateAlignedWithCleanup(n, AllocPolicy());
   } else {
-    return AllocateAlignedAndAddCleanupFallback(n, cleanup);
+    return AllocateAlignedWithCleanupFallback(n, type);
   }
 }
 
-void ArenaImpl::AddCleanup(void* elem, void (*cleanup)(void*)) {
+void ThreadSafeArena::AddCleanup(void* elem, void (*cleanup)(void*)) {
   SerialArena* arena;
-  if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(&arena))) {
-    arena->AddCleanup(elem, cleanup);
+  if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(LifeCycleId(), &arena))) {
+    arena->AddCleanup(elem, cleanup, AllocPolicy());
   } else {
     return AddCleanupFallback(elem, cleanup);
   }
 }
 
 PROTOBUF_NOINLINE
-void* ArenaImpl::AllocateAlignedFallback(size_t n) {
-  return GetSerialArenaFallback(&thread_cache())->AllocateAligned(n);
+void* ThreadSafeArena::AllocateAlignedFallback(size_t n,
+                                               const std::type_info* type) {
+  if (ShouldRecordAlloc()) {
+    RecordAlloc(type, n);
+    SerialArena* arena;
+    if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(LifeCycleId(), &arena))) {
+      return arena->AllocateAligned(n, AllocPolicy());
+    }
+  }
+  return GetSerialArenaFallback(&thread_cache())
+      ->AllocateAligned(n, AllocPolicy());
 }
 
 PROTOBUF_NOINLINE
-void* ArenaImpl::AllocateAlignedAndAddCleanupFallback(size_t n,
-                                                      void (*cleanup)(void*)) {
-  return GetSerialArenaFallback(
-      &thread_cache())->AllocateAlignedAndAddCleanup(n, cleanup);
+std::pair<void*, SerialArena::CleanupNode*>
+ThreadSafeArena::AllocateAlignedWithCleanupFallback(
+    size_t n, const std::type_info* type) {
+  if (ShouldRecordAlloc()) {
+    RecordAlloc(type, n);
+    SerialArena* arena;
+    if (GetSerialArenaFast(LifeCycleId(), &arena)) {
+      return arena->AllocateAlignedWithCleanup(n, AllocPolicy());
+    }
+  }
+  return GetSerialArenaFallback(&thread_cache())
+      ->AllocateAlignedWithCleanup(n, AllocPolicy());
 }
 
 PROTOBUF_NOINLINE
-void ArenaImpl::AddCleanupFallback(void* elem, void (*cleanup)(void*)) {
-  GetSerialArenaFallback(&thread_cache())->AddCleanup(elem, cleanup);
+void ThreadSafeArena::AddCleanupFallback(void* elem, void (*cleanup)(void*)) {
+  GetSerialArenaFallback(&thread_cache())
+      ->AddCleanup(elem, cleanup, AllocPolicy());
 }
 
-PROTOBUF_NOINLINE
-void* SerialArena::AllocateAlignedFallback(size_t n) {
-  // Sync back to current's pos.
-  head_->set_pos(head_->size() - (limit_ - ptr_));
-
-  head_ = NewBlock(head_, n, arena_);
-  ptr_ = head_->Pointer(head_->pos());
-  limit_ = head_->Pointer(head_->size());
-
-#ifdef ADDRESS_SANITIZER
-  ASAN_POISON_MEMORY_REGION(ptr_, limit_ - ptr_);
-#endif  // ADDRESS_SANITIZER
-
-  return AllocateAligned(n);
-}
-
-uint64 ArenaImpl::SpaceAllocated() const {
-  return space_allocated_.load(std::memory_order_relaxed);
-}
-
-uint64 ArenaImpl::SpaceUsed() const {
+uint64 ThreadSafeArena::SpaceAllocated() const {
   SerialArena* serial = threads_.load(std::memory_order_acquire);
-  uint64 space_used = 0;
+  uint64 res = 0;
   for (; serial; serial = serial->next()) {
-    space_used += serial->SpaceUsed();
-  }
-  // Remove the overhead of Options structure, if any.
-  if (options_) {
-    space_used -= kOptionsSize;
+    res += serial->SpaceAllocated();
   }
-  return space_used;
+  return res;
 }
 
-uint64 SerialArena::SpaceUsed() const {
-  // Get current block's size from ptr_ (since we can't trust head_->pos().
-  uint64 space_used = ptr_ - head_->Pointer(kBlockHeaderSize);
-  // Get subsequent block size from b->pos().
-  for (Block* b = head_->next(); b; b = b->next()) {
-    space_used += (b->pos() - kBlockHeaderSize);
-  }
-  // Remove the overhead of the SerialArena itself.
-  space_used -= ArenaImpl::kSerialArenaSize;
-  return space_used;
-}
-
-void ArenaImpl::CleanupList() {
-  // By omitting an Acquire barrier we ensure that any user code that doesn't
-  // properly synchronize Reset() or the destructor will throw a TSAN warning.
-  SerialArena* serial = threads_.load(std::memory_order_relaxed);
-
+uint64 ThreadSafeArena::SpaceUsed() const {
+  SerialArena* serial = threads_.load(std::memory_order_acquire);
+  uint64 space_used = 0;
   for (; serial; serial = serial->next()) {
-    serial->CleanupList();
-  }
-}
-
-void SerialArena::CleanupList() {
-  if (cleanup_ != NULL) {
-    CleanupListFallback();
+    space_used += serial->SpaceUsed();
   }
+  return space_used - (AllocPolicy() ? sizeof(AllocationPolicy) : 0);
 }
 
-void SerialArena::CleanupListFallback() {
-  // The first chunk might be only partially full, so calculate its size
-  // from cleanup_ptr_. Subsequent chunks are always full, so use list->size.
-  size_t n = cleanup_ptr_ - &cleanup_->nodes[0];
-  CleanupChunk* list = cleanup_;
-  while (true) {
-    CleanupNode* node = &list->nodes[0];
-    // Cleanup newest elements first (allocated last).
-    for (size_t i = n; i > 0; i--) {
-      node[i - 1].cleanup(node[i - 1].elem);
-    }
-    list = list->next;
-    if (list == nullptr) {
-      break;
-    }
-    // All but the first chunk are always full.
-    n = list->size;
-  }
-}
-
-SerialArena* SerialArena::New(Block* b, void* owner, ArenaImpl* arena) {
-  auto pos = b->pos();
-  GOOGLE_DCHECK_LE(pos + ArenaImpl::kSerialArenaSize, b->size());
-  SerialArena* serial = reinterpret_cast<SerialArena*>(b->Pointer(pos));
-  b->set_pos(pos + ArenaImpl::kSerialArenaSize);
-  serial->arena_ = arena;
-  serial->owner_ = owner;
-  serial->head_ = b;
-  serial->ptr_ = b->Pointer(b->pos());
-  serial->limit_ = b->Pointer(b->size());
-  serial->cleanup_ = NULL;
-  serial->cleanup_ptr_ = NULL;
-  serial->cleanup_limit_ = NULL;
-  return serial;
+void ThreadSafeArena::CleanupList() {
+  PerSerialArena([](SerialArena* a) { a->CleanupList(); });
 }
 
 PROTOBUF_NOINLINE
-SerialArena* ArenaImpl::GetSerialArenaFallback(void* me) {
+SerialArena* ThreadSafeArena::GetSerialArenaFallback(void* me) {
   // Look for this SerialArena in our linked list.
   SerialArena* serial = threads_.load(std::memory_order_acquire);
   for (; serial; serial = serial->next()) {
@@ -422,8 +444,8 @@ SerialArena* ArenaImpl::GetSerialArenaFallback(void* me) {
   if (!serial) {
     // This thread doesn't have any SerialArena, which also means it doesn't
     // have any blocks yet.  So we'll allocate its first block now.
-    SerialArena::Block* b = SerialArena::NewBlock(NULL, kSerialArenaSize, this);
-    serial = SerialArena::New(b, me, this);
+    serial = SerialArena::New(
+        AllocateMemory(AllocPolicy(), 0, kSerialArenaSize), me);
 
     SerialArena* head = threads_.load(std::memory_order_relaxed);
     do {
@@ -436,14 +458,25 @@ SerialArena* ArenaImpl::GetSerialArenaFallback(void* me) {
   return serial;
 }
 
-ArenaMetricsCollector::~ArenaMetricsCollector() {}
-
 }  // namespace internal
 
 PROTOBUF_FUNC_ALIGN(32)
 void* Arena::AllocateAlignedNoHook(size_t n) {
-  return impl_.AllocateAligned(n);
+  return impl_.AllocateAligned(n, nullptr);
+}
+
+PROTOBUF_FUNC_ALIGN(32)
+void* Arena::AllocateAlignedWithHook(size_t n, const std::type_info* type) {
+  return impl_.AllocateAligned(n, type);
+}
+
+PROTOBUF_FUNC_ALIGN(32)
+std::pair<void*, internal::SerialArena::CleanupNode*>
+Arena::AllocateAlignedWithCleanup(size_t n, const std::type_info* type) {
+  return impl_.AllocateAlignedWithCleanup(n, type);
 }
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/arena.h

@@ -93,11 +93,28 @@ class EpsCopyInputStream;  // defined in parse_context.h
 template <typename Type>
 class GenericTypeHandler;  // defined in repeated_field.h
 
+PROTOBUF_ALWAYS_INLINE
+inline void* AlignTo(void* ptr, size_t align) {
+  return reinterpret_cast<void*>(
+      (reinterpret_cast<uintptr_t>(ptr) + align - 1) & (~align + 1));
+}
+
 // Templated cleanup methods.
 template <typename T>
 void arena_destruct_object(void* object) {
   reinterpret_cast<T*>(object)->~T();
 }
+
+template <bool destructor_skippable, typename T>
+struct ObjectDestructor {
+  constexpr static void (*destructor)(void*) = &arena_destruct_object<T>;
+};
+
+template <typename T>
+struct ObjectDestructor<true, T> {
+  constexpr static void (*destructor)(void*) = nullptr;
+};
+
 template <typename T>
 void arena_delete_object(void* object) {
   delete reinterpret_cast<T*>(object);
@@ -138,34 +155,38 @@ struct ArenaOptions {
   void (*block_dealloc)(void*, size_t);
 
   ArenaOptions()
-      : start_block_size(kDefaultStartBlockSize),
-        max_block_size(kDefaultMaxBlockSize),
+      : start_block_size(internal::AllocationPolicy::kDefaultStartBlockSize),
+        max_block_size(internal::AllocationPolicy::kDefaultMaxBlockSize),
         initial_block(NULL),
         initial_block_size(0),
-        block_alloc(kDefaultBlockAlloc),
-        block_dealloc(&internal::ArenaFree),
+        block_alloc(nullptr),
+        block_dealloc(nullptr),
         make_metrics_collector(nullptr) {}
 
-  PROTOBUF_EXPORT static void* (*const kDefaultBlockAlloc)(size_t);
-
  private:
   // If make_metrics_collector is not nullptr, it will be called at Arena init
   // time. It may return a pointer to a collector instance that will be notified
   // of interesting events related to the arena.
   internal::ArenaMetricsCollector* (*make_metrics_collector)();
 
-  // Constants define default starting block size and max block size for
-  // arena allocator behavior -- see descriptions above.
-  static const size_t kDefaultStartBlockSize =
-      internal::ArenaImpl::kDefaultStartBlockSize;
-  static const size_t kDefaultMaxBlockSize =
-      internal::ArenaImpl::kDefaultMaxBlockSize;
+  internal::ArenaMetricsCollector* MetricsCollector() const {
+    return make_metrics_collector ? (*make_metrics_collector)() : nullptr;
+  }
+
+  internal::AllocationPolicy AllocationPolicy() const {
+    internal::AllocationPolicy res;
+    res.start_block_size = start_block_size;
+    res.max_block_size = max_block_size;
+    res.block_alloc = block_alloc;
+    res.block_dealloc = block_dealloc;
+    res.metrics_collector = MetricsCollector();
+    return res;
+  }
 
   friend void arena_metrics::EnableArenaMetrics(ArenaOptions*);
 
   friend class Arena;
   friend class ArenaOptionsTestFriend;
-  friend class internal::ArenaImpl;
 };
 
 // Support for non-RTTI environments. (The metrics hooks API uses type
@@ -236,7 +257,9 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
 
   // Arena constructor taking custom options. See ArenaOptions above for
   // descriptions of the options available.
-  explicit Arena(const ArenaOptions& options) : impl_(options) {}
+  explicit Arena(const ArenaOptions& options)
+      : impl_(options.initial_block, options.initial_block_size,
+              options.AllocationPolicy()) {}
 
   // Block overhead.  Use this as a guide for how much to over-allocate the
   // initial block if you want an allocation of size N to fit inside it.
@@ -244,8 +267,9 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // WARNING: if you allocate multiple objects, it is difficult to guarantee
   // that a series of allocations will fit in the initial block, especially if
   // Arena changes its alignment guarantees in the future!
-  static const size_t kBlockOverhead = internal::ArenaImpl::kBlockHeaderSize +
-                                       internal::ArenaImpl::kSerialArenaSize;
+  static const size_t kBlockOverhead =
+      internal::ThreadSafeArena::kBlockHeaderSize +
+      internal::ThreadSafeArena::kSerialArenaSize;
 
   inline ~Arena() {}
 
@@ -290,8 +314,16 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // is obtained from the arena).
   template <typename T, typename... Args>
   PROTOBUF_ALWAYS_INLINE static T* Create(Arena* arena, Args&&... args) {
-    return CreateNoMessage<T>(arena, is_arena_constructable<T>(),
-                              std::forward<Args>(args)...);
+    if (arena == NULL) {
+      return new T(std::forward<Args>(args)...);
+    } else {
+      auto destructor =
+          internal::ObjectDestructor<std::is_trivially_destructible<T>::value,
+                                     T>::destructor;
+      return new (arena->AllocateInternal(sizeof(T), alignof(T), destructor,
+                                          RTTI_TYPE_ID(T)))
+          T(std::forward<Args>(args)...);
+    }
   }
 
   // Create an array of object type T on the arena *without* invoking the
@@ -316,9 +348,12 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     }
   }
 
+  // The following are routines are for monitoring. They will aproximate the
+  // total sum allocated and used memory, but the exact value is an
+  // implementation deal. For instance allocated space depends on growth
+  // policies. Do not use these in unit tests.
   // Returns the total space allocated by the arena, which is the sum of the
-  // sizes of the underlying blocks. This method is relatively fast; a counter
-  // is kept as blocks are allocated.
+  // sizes of the underlying blocks.
   uint64 SpaceAllocated() const { return impl_.SpaceAllocated(); }
   // Returns the total space used by the arena. Similar to SpaceAllocated but
   // does not include free space and block overhead. The total space returned
@@ -336,8 +371,8 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // Adds |object| to a list of heap-allocated objects to be freed with |delete|
   // when the arena is destroyed or reset.
   template <typename T>
-  PROTOBUF_NOINLINE void Own(T* object) {
-    OwnInternal(object, std::is_convertible<T*, Message*>());
+  PROTOBUF_ALWAYS_INLINE void Own(T* object) {
+    OwnInternal(object, std::is_convertible<T*, MessageLite*>());
   }
 
   // Adds |object| to a list of objects whose destructors will be manually
@@ -346,7 +381,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // normally only used for objects that are placement-newed into
   // arena-allocated memory.
   template <typename T>
-  PROTOBUF_NOINLINE void OwnDestructor(T* object) {
+  PROTOBUF_ALWAYS_INLINE void OwnDestructor(T* object) {
     if (object != NULL) {
       impl_.AddCleanup(object, &internal::arena_destruct_object<T>);
     }
@@ -356,8 +391,8 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // will be manually called when the arena is destroyed or reset. This differs
   // from OwnDestructor() in that any member function may be specified, not only
   // the class destructor.
-  PROTOBUF_NOINLINE void OwnCustomDestructor(void* object,
-                                             void (*destruct)(void*)) {
+  PROTOBUF_ALWAYS_INLINE void OwnCustomDestructor(void* object,
+                                                  void (*destruct)(void*)) {
     impl_.AddCleanup(object, destruct);
   }
 
@@ -436,6 +471,8 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   };
 
  private:
+  internal::ThreadSafeArena impl_;
+
   template <typename T>
   struct has_get_arena : InternalHelper<T>::has_get_arena {};
 
@@ -467,41 +504,26 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     }
   }
 
-  template <typename T, typename... Args>
-  PROTOBUF_ALWAYS_INLINE static T* CreateInternal(Arena* arena,
-                                                  Args&&... args) {
-    if (arena == NULL) {
-      return new T(std::forward<Args>(args)...);
-    } else {
-      return arena->DoCreate<T>(std::is_trivially_destructible<T>::value,
-                                std::forward<Args>(args)...);
-    }
-  }
-
-  inline void AllocHook(const std::type_info* allocated_type, size_t n) const {
-    impl_.RecordAlloc(allocated_type, n);
-  }
-
   // Allocate and also optionally call collector with the allocated type info
   // when allocation recording is enabled.
-  template <typename T>
-  PROTOBUF_ALWAYS_INLINE void* AllocateInternal(bool skip_explicit_ownership) {
-    const size_t n = internal::AlignUpTo8(sizeof(T));
+  PROTOBUF_ALWAYS_INLINE void* AllocateInternal(size_t size, size_t align,
+                                                void (*destructor)(void*),
+                                                const std::type_info* type) {
     // Monitor allocation if needed.
-    impl_.RecordAlloc(RTTI_TYPE_ID(T), n);
-    if (skip_explicit_ownership) {
-      return AllocateAlignedTo<alignof(T)>(sizeof(T));
+    if (destructor == nullptr) {
+      return AllocateAlignedWithHook(size, align, type);
     } else {
-      if (alignof(T) <= 8) {
-        return impl_.AllocateAlignedAndAddCleanup(
-            n, &internal::arena_destruct_object<T>);
+      if (align <= 8) {
+        auto res = AllocateAlignedWithCleanup(internal::AlignUpTo8(size), type);
+        res.second->elem = res.first;
+        res.second->cleanup = destructor;
+        return res.first;
       } else {
-        auto ptr =
-            reinterpret_cast<uintptr_t>(impl_.AllocateAlignedAndAddCleanup(
-                sizeof(T) + alignof(T) - 8,
-                &internal::arena_destruct_object<T>));
-        return reinterpret_cast<void*>((ptr + alignof(T) - 8) &
-                                       (~alignof(T) + 1));
+        auto res = AllocateAlignedWithCleanup(size + align - 8, type);
+        auto ptr = internal::AlignTo(res.first, align);
+        res.second->elem = ptr;
+        res.second->cleanup = destructor;
+        return ptr;
       }
     }
   }
@@ -522,7 +544,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   PROTOBUF_ALWAYS_INLINE static T* DoCreateMaybeMessage(Arena* arena,
                                                         std::false_type,
                                                         Args&&... args) {
-    return CreateInternal<T>(arena, std::forward<Args>(args)...);
+    return Create<T>(arena, std::forward<Args>(args)...);
   }
 
   template <typename T, typename... Args>
@@ -532,25 +554,6 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
                                    std::forward<Args>(args)...);
   }
 
-  template <typename T, typename... Args>
-  PROTOBUF_ALWAYS_INLINE static T* CreateNoMessage(Arena* arena, std::true_type,
-                                                   Args&&... args) {
-    // User is constructing with Create() despite the fact that T supports arena
-    // construction.  In this case we have to delegate to CreateInternal(), and
-    // we can't use any CreateMaybeMessage() specialization that may be defined.
-    return CreateInternal<T>(arena, std::forward<Args>(args)...);
-  }
-
-  template <typename T, typename... Args>
-  PROTOBUF_ALWAYS_INLINE static T* CreateNoMessage(Arena* arena,
-                                                   std::false_type,
-                                                   Args&&... args) {
-    // User is constructing with Create() and the type does not support arena
-    // construction.  In this case we can delegate to CreateMaybeMessage() and
-    // use any specialization that may be available for that.
-    return CreateMaybeMessage<T>(arena, std::forward<Args>(args)...);
-  }
-
   // Just allocate the required size for the given type assuming the
   // type has a trivial constructor.
   template <typename T>
@@ -559,22 +562,19 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
         << "Requested size is too large to fit into size_t.";
     // We count on compiler to realize that if sizeof(T) is a multiple of
     // 8 AlignUpTo can be elided.
-    const size_t n = internal::AlignUpTo8(sizeof(T) * num_elements);
-    // Monitor allocation if needed.
-    impl_.RecordAlloc(RTTI_TYPE_ID(T), n);
-    return static_cast<T*>(AllocateAlignedTo<alignof(T)>(n));
+    const size_t n = sizeof(T) * num_elements;
+    return static_cast<T*>(
+        AllocateAlignedWithHook(n, alignof(T), RTTI_TYPE_ID(T)));
   }
 
-  template <typename T, typename... Args>
-  PROTOBUF_ALWAYS_INLINE T* DoCreate(bool skip_explicit_ownership,
-                                     Args&&... args) {
-    return new (AllocateInternal<T>(skip_explicit_ownership))
-        T(std::forward<Args>(args)...);
-  }
   template <typename T, typename... Args>
   PROTOBUF_ALWAYS_INLINE T* DoCreateMessage(Args&&... args) {
     return InternalHelper<T>::Construct(
-        AllocateInternal<T>(InternalHelper<T>::is_destructor_skippable::value),
+        AllocateInternal(sizeof(T), alignof(T),
+                         internal::ObjectDestructor<
+                             InternalHelper<T>::is_destructor_skippable::value,
+                             T>::destructor,
+                         RTTI_TYPE_ID(T)),
         this, std::forward<Args>(args)...);
   }
 
@@ -619,7 +619,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   template <typename T>
   PROTOBUF_ALWAYS_INLINE void OwnInternal(T* object, std::true_type) {
     if (object != NULL) {
-      impl_.AddCleanup(object, &internal::arena_delete_object<Message>);
+      impl_.AddCleanup(object, &internal::arena_delete_object<MessageLite>);
     }
   }
   template <typename T>
@@ -654,24 +654,38 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   }
 
   // For friends of arena.
-  void* AllocateAligned(size_t n) {
-    return AllocateAlignedNoHook(internal::AlignUpTo8(n));
+  void* AllocateAligned(size_t n, size_t align = 8) {
+    if (align <= 8) {
+      return AllocateAlignedNoHook(internal::AlignUpTo8(n));
+    } else {
+      // We are wasting space by over allocating align - 8 bytes. Compared
+      // to a dedicated function that takes current alignment in consideration.
+      // Such a scheme would only waste (align - 8)/2 bytes on average, but
+      // requires a dedicated function in the outline arena allocation
+      // functions. Possibly re-evaluate tradeoffs later.
+      return internal::AlignTo(AllocateAlignedNoHook(n + align - 8), align);
+    }
   }
-  template<size_t Align>
-  void* AllocateAlignedTo(size_t n) {
-    static_assert(Align > 0, "Alignment must be greater than 0");
-    static_assert((Align & (Align - 1)) == 0, "Alignment must be power of two");
-    if (Align <= 8) return AllocateAligned(n);
-    // TODO(b/151247138): if the pointer would have been aligned already,
-    // this is wasting space. We should pass the alignment down.
-    uintptr_t ptr = reinterpret_cast<uintptr_t>(AllocateAligned(n + Align - 8));
-    ptr = (ptr + Align - 1) & (~Align + 1);
-    return reinterpret_cast<void*>(ptr);
+
+  void* AllocateAlignedWithHook(size_t n, size_t align,
+                                const std::type_info* type) {
+    if (align <= 8) {
+      return AllocateAlignedWithHook(internal::AlignUpTo8(n), type);
+    } else {
+      // We are wasting space by over allocating align - 8 bytes. Compared
+      // to a dedicated function that takes current alignment in consideration.
+      // Such a schemee would only waste (align - 8)/2 bytes on average, but
+      // requires a dedicated function in the outline arena allocation
+      // functions. Possibly re-evaluate tradeoffs later.
+      return internal::AlignTo(AllocateAlignedWithHook(n + align - 8, type),
+                               align);
+    }
   }
 
   void* AllocateAlignedNoHook(size_t n);
-
-  internal::ArenaImpl impl_;
+  void* AllocateAlignedWithHook(size_t n, const std::type_info* type);
+  std::pair<void*, internal::SerialArena::CleanupNode*>
+  AllocateAlignedWithCleanup(size_t n, const std::type_info* type);
 
   template <typename Type>
   friend class internal::GenericTypeHandler;

src/google/protobuf/arena_impl.h

@@ -35,6 +35,7 @@
 
 #include <atomic>
 #include <limits>
+#include <typeinfo>
 
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
@@ -48,24 +49,19 @@
 
 namespace google {
 namespace protobuf {
-
-struct ArenaOptions;
-
 namespace internal {
 
-inline size_t AlignUpTo8(size_t n) {
+inline constexpr size_t AlignUpTo8(size_t n) {
   // Align n to next multiple of 8 (from Hacker's Delight, Chapter 3.)
   return (n + 7) & static_cast<size_t>(-8);
 }
 
 using LifecycleIdAtomic = uint64_t;
 
-void PROTOBUF_EXPORT ArenaFree(void* object, size_t size);
-
 // MetricsCollector collects stats for a particular arena.
 class PROTOBUF_EXPORT ArenaMetricsCollector {
  public:
-  virtual ~ArenaMetricsCollector();
+  ArenaMetricsCollector(bool record_allocs) : record_allocs_(record_allocs) {}
 
   // Invoked when the arena is about to be destroyed. This method will
   // typically finalize any metric collection and delete the collector.
@@ -76,10 +72,6 @@ class PROTOBUF_EXPORT ArenaMetricsCollector {
   // space_allocated is the space used by the arena just before the reset.
   virtual void OnReset(uint64 space_allocated) = 0;
 
-  // Does OnAlloc() need to be called?  If false, metric collection overhead
-  // will be reduced since we will not do extra work per allocation.
-  virtual bool RecordAllocs() = 0;
-
   // OnAlloc is called when an allocation happens.
   // type_info is promised to be static - its lifetime extends to
   // match program's lifetime (It is given by typeid operator).
@@ -88,78 +80,79 @@ class PROTOBUF_EXPORT ArenaMetricsCollector {
   // allocations for managing the arena)
   virtual void OnAlloc(const std::type_info* allocated_type,
                        uint64 alloc_size) = 0;
-};
-
-class ArenaImpl;
-
-// A thread-unsafe Arena that can only be used within its owning thread.
-class PROTOBUF_EXPORT SerialArena {
- public:
-  // Blocks are variable length malloc-ed objects.  The following structure
-  // describes the common header for all blocks.
-  class PROTOBUF_EXPORT Block {
-   public:
-    Block(size_t size, Block* next, bool special, bool user_owned)
-        : next_and_bits_(reinterpret_cast<uintptr_t>(next) | (special ? 1 : 0) |
-                         (user_owned ? 2 : 0)),
-          pos_(kBlockHeaderSize),
-          size_(size) {
-      GOOGLE_DCHECK_EQ(reinterpret_cast<uintptr_t>(next) & 3, 0u);
-    }
-
-    char* Pointer(size_t n) {
-      GOOGLE_DCHECK(n <= size_);
-      return reinterpret_cast<char*>(this) + n;
-    }
 
-    // One of the blocks may be special. This is either a user-supplied
-    // initial block, or a block we created at startup to hold Options info.
-    // A special block is not deleted by Reset.
-    bool special() const { return (next_and_bits_ & 1) != 0; }
-
-    // Whether or not this current block is owned by the user.
-    // Only special blocks can be user_owned.
-    bool user_owned() const { return (next_and_bits_ & 2) != 0; }
+  // Does OnAlloc() need to be called?  If false, metric collection overhead
+  // will be reduced since we will not do extra work per allocation.
+  bool RecordAllocs() { return record_allocs_; }
 
-    Block* next() const {
-      const uintptr_t bottom_bits = 3;
-      return reinterpret_cast<Block*>(next_and_bits_ & ~bottom_bits);
-    }
+ protected:
+  // This class is destructed by the call to OnDestroy().
+  ~ArenaMetricsCollector() = default;
+  const bool record_allocs_;
+};
 
-    void clear_next() {
-      next_and_bits_ &= 3;  // Set next to nullptr, preserve bottom bits.
-    }
+struct AllocationPolicy {
+  static constexpr size_t kDefaultStartBlockSize = 256;
+  static constexpr size_t kDefaultMaxBlockSize = 8192;
 
-    size_t pos() const { return pos_; }
-    size_t size() const { return size_; }
-    void set_pos(size_t pos) { pos_ = pos; }
+  size_t start_block_size = kDefaultStartBlockSize;
+  size_t max_block_size = kDefaultMaxBlockSize;
+  void* (*block_alloc)(size_t) = nullptr;
+  void (*block_dealloc)(void*, size_t) = nullptr;
+  ArenaMetricsCollector* metrics_collector = nullptr;
 
-   private:
-    // Holds pointer to next block for this thread + special/user_owned bits.
-    uintptr_t next_and_bits_;
+  bool IsDefault() const {
+    return start_block_size == kDefaultMaxBlockSize &&
+           max_block_size == kDefaultMaxBlockSize && block_alloc == nullptr &&
+           block_dealloc == nullptr && metrics_collector == nullptr;
+  }
+};
 
-    size_t pos_;
-    size_t size_;
-    // data follows
+// A simple arena allocator. Calls to allocate functions must be properly
+// serialized by the caller, hence this class cannot be used as a general
+// purpose allocator in a multi-threaded program. It serves as a building block
+// for ThreadSafeArena, which provides a thread-safe arena allocator.
+//
+// This class manages
+// 1) Arena bump allocation + owning memory blocks.
+// 2) Maintaining a cleanup list.
+// It delagetes the actual memory allocation back to ThreadSafeArena, which
+// contains the information on block growth policy and backing memory allocation
+// used.
+class PROTOBUF_EXPORT SerialArena {
+ public:
+  struct Memory {
+    void* ptr;
+    size_t size;
   };
 
-  // The allocate/free methods here are a little strange, since SerialArena is
-  // allocated inside a Block which it also manages.  This is to avoid doing
-  // an extra allocation for the SerialArena itself.
+  // Node contains the ptr of the object to be cleaned up and the associated
+  // cleanup function ptr.
+  struct CleanupNode {
+    void* elem;              // Pointer to the object to be cleaned up.
+    void (*cleanup)(void*);  // Function pointer to the destructor or deleter.
+  };
 
-  // Creates a new SerialArena inside Block* and returns it.
-  static SerialArena* New(Block* b, void* owner, ArenaImpl* arena);
+  // Creates a new SerialArena inside mem using the remaining memory as for
+  // future allocations.
+  static SerialArena* New(SerialArena::Memory mem, void* owner);
+  // Free SerialArena returning the memory passed in to New
+  template <typename Deallocator>
+  Memory Free(Deallocator deallocator);
 
   void CleanupList();
+  uint64 SpaceAllocated() const {
+    return space_allocated_.load(std::memory_order_relaxed);
+  }
   uint64 SpaceUsed() const;
 
   bool HasSpace(size_t n) { return n <= static_cast<size_t>(limit_ - ptr_); }
 
-  void* AllocateAligned(size_t n) {
+  void* AllocateAligned(size_t n, const AllocationPolicy* policy) {
     GOOGLE_DCHECK_EQ(internal::AlignUpTo8(n), n);  // Must be already aligned.
     GOOGLE_DCHECK_GE(limit_, ptr_);
     if (PROTOBUF_PREDICT_FALSE(!HasSpace(n))) {
-      return AllocateAlignedFallback(n);
+      return AllocateAlignedFallback(n, policy);
     }
     void* ret = ptr_;
     ptr_ += n;
@@ -183,51 +176,52 @@ class PROTOBUF_EXPORT SerialArena {
     return true;
   }
 
-  void AddCleanup(void* elem, void (*cleanup)(void*)) {
-    if (PROTOBUF_PREDICT_FALSE(cleanup_ptr_ == cleanup_limit_)) {
-      AddCleanupFallback(elem, cleanup);
-      return;
+  std::pair<void*, CleanupNode*> AllocateAlignedWithCleanup(
+      size_t n, const AllocationPolicy* policy) {
+    if (PROTOBUF_PREDICT_FALSE(!HasSpace(n + kCleanupSize))) {
+      return AllocateAlignedWithCleanupFallback(n, policy);
     }
-    cleanup_ptr_->elem = elem;
-    cleanup_ptr_->cleanup = cleanup;
-    cleanup_ptr_++;
+    void* ret = ptr_;
+    ptr_ += n;
+    limit_ -= kCleanupSize;
+#ifdef ADDRESS_SANITIZER
+    ASAN_UNPOISON_MEMORY_REGION(ret, n);
+    ASAN_UNPOISON_MEMORY_REGION(limit_, kCleanupSize);
+#endif  // ADDRESS_SANITIZER
+    return CreatePair(ret, reinterpret_cast<CleanupNode*>(limit_));
   }
 
-  void* AllocateAlignedAndAddCleanup(size_t n, void (*cleanup)(void*)) {
-    void* ret = AllocateAligned(n);
-    AddCleanup(ret, cleanup);
-    return ret;
+  void AddCleanup(void* elem, void (*cleanup)(void*),
+                  const AllocationPolicy* policy) {
+    auto res = AllocateAlignedWithCleanup(0, policy);
+    res.second->elem = elem;
+    res.second->cleanup = cleanup;
   }
 
-  Block* head() const { return head_; }
   void* owner() const { return owner_; }
   SerialArena* next() const { return next_; }
   void set_next(SerialArena* next) { next_ = next; }
-  static Block* NewBlock(Block* last_block, size_t min_bytes, ArenaImpl* arena);
 
  private:
-  // Node contains the ptr of the object to be cleaned up and the associated
-  // cleanup function ptr.
-  struct CleanupNode {
-    void* elem;              // Pointer to the object to be cleaned up.
-    void (*cleanup)(void*);  // Function pointer to the destructor or deleter.
-  };
-
-  // Cleanup uses a chunked linked list, to reduce pointer chasing.
-  struct CleanupChunk {
-    static size_t SizeOf(size_t i) {
-      return sizeof(CleanupChunk) + (sizeof(CleanupNode) * (i - 1));
+  // Blocks are variable length malloc-ed objects.  The following structure
+  // describes the common header for all blocks.
+  struct Block {
+    char* Pointer(size_t n) {
+      GOOGLE_DCHECK(n <= size);
+      return reinterpret_cast<char*>(this) + n;
     }
-    size_t size;           // Total elements in the list.
-    CleanupChunk* next;    // Next node in the list.
-    CleanupNode nodes[1];  // True length is |size|.
+
+    Block* next;
+    size_t size;
+    CleanupNode* start;
+    // data follows
   };
 
-  ArenaImpl* arena_;       // Containing arena.
   void* owner_;            // &ThreadCache of this thread;
   Block* head_;            // Head of linked list of blocks.
-  CleanupChunk* cleanup_;  // Head of cleanup list.
   SerialArena* next_;      // Next SerialArena in this linked list.
+  size_t space_used_ = 0;  // Necessary for metrics.
+  std::atomic<size_t> space_allocated_;
 
   // Next pointer to allocate from.  Always 8-byte aligned.  Points inside
   // head_ (and head_->pos will always be non-canonical).  We keep these
@@ -235,17 +229,20 @@ class PROTOBUF_EXPORT SerialArena {
   char* ptr_;
   char* limit_;
 
-  // Next CleanupList members to append to.  These point inside cleanup_.
-  CleanupNode* cleanup_ptr_;
-  CleanupNode* cleanup_limit_;
+  // contructor private as to only New should be used.
+  inline SerialArena(Block* b, void* owner);
+  void* AllocateAlignedFallback(size_t n, const AllocationPolicy* policy);
+  std::pair<void*, CleanupNode*> AllocateAlignedWithCleanupFallback(
+      size_t n, const AllocationPolicy* policy);
+  void AllocateNewBlock(size_t n, const AllocationPolicy* policy);
 
-  void* AllocateAlignedFallback(size_t n);
-  void AddCleanupFallback(void* elem, void (*cleanup)(void*));
-  void CleanupListFallback();
+  std::pair<void*, CleanupNode*> CreatePair(void* ptr, CleanupNode* node) {
+    return {ptr, node};
+  }
 
  public:
-  static constexpr size_t kBlockHeaderSize =
-      (sizeof(Block) + 7) & static_cast<size_t>(-8);
+  static constexpr size_t kBlockHeaderSize = AlignUpTo8(sizeof(Block));
+  static constexpr size_t kCleanupSize = AlignUpTo8(sizeof(CleanupNode));
 };
 
 // This class provides the core Arena memory allocation library. Different
@@ -254,42 +251,43 @@ class PROTOBUF_EXPORT SerialArena {
 // in turn would be templates, which will/cannot happen. However separating
 // the memory allocation part from the cruft of the API users expect we can
 // use #ifdef the select the best implementation based on hardware / OS.
-class PROTOBUF_EXPORT ArenaImpl {
+class PROTOBUF_EXPORT ThreadSafeArena {
  public:
-  static const size_t kDefaultStartBlockSize = 256;
-  static const size_t kDefaultMaxBlockSize = 8192;
-
-  ArenaImpl() { Init(false); }
+  ThreadSafeArena() { Init(false); }
 
-  ArenaImpl(char* mem, size_t size) {
-    GOOGLE_DCHECK_EQ(reinterpret_cast<uintptr_t>(mem) & 7, 0u);
-    Init(false);
+  ThreadSafeArena(char* mem, size_t size) { InitializeFrom(mem, size); }
 
-    // Ignore initial block if it is too small.
-    if (mem != nullptr && size >= kBlockHeaderSize + kSerialArenaSize) {
-      SetInitialBlock(new (mem) SerialArena::Block(size, nullptr, true, true));
+  explicit ThreadSafeArena(void* mem, size_t size,
+                           const AllocationPolicy& policy) {
+    if (policy.IsDefault()) {
+      // Legacy code doesn't use the API above, but provides the initial block
+      // through ArenaOptions. I suspect most do not touch the allocation
+      // policy parameters.
+      InitializeFrom(mem, size);
+    } else {
+      auto collector = policy.metrics_collector;
+      bool record_allocs = collector && collector->RecordAllocs();
+      InitializeWithPolicy(mem, size, record_allocs, policy);
     }
   }
 
-  explicit ArenaImpl(const ArenaOptions& options);
-
   // Destructor deletes all owned heap allocated objects, and destructs objects
   // that have non-trivial destructors, except for proto2 message objects whose
   // destructors can be skipped. Also, frees all blocks except the initial block
   // if it was passed in.
-  ~ArenaImpl();
+  ~ThreadSafeArena();
 
   uint64 Reset();
 
   uint64 SpaceAllocated() const;
   uint64 SpaceUsed() const;
 
-  void* AllocateAligned(size_t n) {
+  void* AllocateAligned(size_t n, const std::type_info* type) {
     SerialArena* arena;
-    if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(&arena))) {
-      return arena->AllocateAligned(n);
+    if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFast(tag_and_id_, &arena))) {
+      return arena->AllocateAligned(n, AllocPolicy());
     } else {
-      return AllocateAlignedFallback(n);
+      return AllocateAlignedFallback(n, type);
     }
   }
 
@@ -300,90 +298,74 @@ class PROTOBUF_EXPORT ArenaImpl {
   // code for the happy path.
   PROTOBUF_ALWAYS_INLINE bool MaybeAllocateAligned(size_t n, void** out) {
     SerialArena* a;
-    if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFromThreadCache(&a))) {
+    if (PROTOBUF_PREDICT_TRUE(GetSerialArenaFromThreadCache(tag_and_id_, &a))) {
       return a->MaybeAllocateAligned(n, out);
     }
     return false;
   }
 
-  void* AllocateAlignedAndAddCleanup(size_t n, void (*cleanup)(void*));
+  std::pair<void*, SerialArena::CleanupNode*> AllocateAlignedWithCleanup(
+      size_t n, const std::type_info* type);
 
   // Add object pointer and cleanup function pointer to the list.
   void AddCleanup(void* elem, void (*cleanup)(void*));
 
-  inline void RecordAlloc(const std::type_info* allocated_type,
-                          size_t n) const {
-    if (PROTOBUF_PREDICT_FALSE(record_allocs())) {
-      options_->metrics_collector->OnAlloc(allocated_type, n);
-    }
-  }
+ private:
+  // Unique for each arena. Changes on Reset().
+  uint64 tag_and_id_;
+  // The LSB of tag_and_id_ indicates if allocs in this arena are recorded.
+  enum { kRecordAllocs = 1 };
 
-  std::pair<void*, size_t> NewBuffer(size_t last_size, size_t min_bytes);
+  intptr_t alloc_policy_ = 0;  // Tagged pointer to AllocPolicy.
+  // The LSB of alloc_policy_ indicates if the user owns the initial block.
+  enum { kUserOwnedInitialBlock = 1 };
 
- private:
   // Pointer to a linked list of SerialArena.
   std::atomic<SerialArena*> threads_;
-  std::atomic<SerialArena*> hint_;       // Fast thread-local block access
-  std::atomic<size_t> space_allocated_;  // Total size of all allocated blocks.
-
-  // Unique for each arena. Changes on Reset().
-  // Least-significant-bit is 1 iff allocations should be recorded.
-  uint64 lifecycle_id_;
-
-  struct Options {
-    size_t start_block_size;
-    size_t max_block_size;
-    void* (*block_alloc)(size_t);
-    void (*block_dealloc)(void*, size_t);
-    ArenaMetricsCollector* metrics_collector;
-  };
+  std::atomic<SerialArena*> hint_;  // Fast thread-local block access
 
-  Options* options_ = nullptr;
-
-  void* AllocateAlignedFallback(size_t n);
-  void* AllocateAlignedAndAddCleanupFallback(size_t n, void (*cleanup)(void*));
+  const AllocationPolicy* AllocPolicy() const {
+    return reinterpret_cast<const AllocationPolicy*>(alloc_policy_ & -8);
+  }
+  void InitializeFrom(void* mem, size_t size);
+  void InitializeWithPolicy(void* mem, size_t size, bool record_allocs,
+                            AllocationPolicy policy);
+  void* AllocateAlignedFallback(size_t n, const std::type_info* type);
+  std::pair<void*, SerialArena::CleanupNode*>
+  AllocateAlignedWithCleanupFallback(size_t n, const std::type_info* type);
   void AddCleanupFallback(void* elem, void (*cleanup)(void*));
 
   void Init(bool record_allocs);
-  void SetInitialBlock(
-      SerialArena::Block* block);  // Can be called right after Init()
+  void SetInitialBlock(void* mem, size_t size);
 
-  // Return true iff allocations should be recorded in a metrics collector.
-  inline bool record_allocs() const { return lifecycle_id_ & 1; }
+  // Delete or Destruct all objects owned by the arena.
+  void CleanupList();
 
-  // Invoke fn(b) for every Block* b.
-  template <typename Functor>
-  void PerBlock(Functor fn) {
-    // By omitting an Acquire barrier we ensure that any user code that doesn't
-    // properly synchronize Reset() or the destructor will throw a TSAN warning.
-    SerialArena* serial = threads_.load(std::memory_order_relaxed);
-    while (serial) {
-      // fn() may delete blocks and arenas, so fetch next pointers before fn();
-      SerialArena* cur = serial;
-      serial = serial->next();
-      for (auto* block = cur->head(); block != nullptr;) {
-        auto* b = block;
-        block = b->next();
-        fn(b);
-      }
-    }
+  inline bool ShouldRecordAlloc() const { return tag_and_id_ & kRecordAllocs; }
+
+  inline uint64 LifeCycleId() const {
+    return tag_and_id_ & (-kRecordAllocs - 1);
   }
 
-  // Delete or Destruct all objects owned by the arena.
-  void CleanupList();
+  inline void RecordAlloc(const std::type_info* allocated_type,
+                          size_t n) const {
+    AllocPolicy()->metrics_collector->OnAlloc(allocated_type, n);
+  }
 
   inline void CacheSerialArena(SerialArena* serial) {
     thread_cache().last_serial_arena = serial;
-    thread_cache().last_lifecycle_id_seen = lifecycle_id_;
+    thread_cache().last_lifecycle_id_seen = LifeCycleId();
     // TODO(haberman): evaluate whether we would gain efficiency by getting rid
-    // of hint_.  It's the only write we do to ArenaImpl in the allocation path,
-    // which will dirty the cache line.
+    // of hint_.  It's the only write we do to ThreadSafeArena in the allocation
+    // path, which will dirty the cache line.
 
     hint_.store(serial, std::memory_order_release);
   }
 
-  PROTOBUF_ALWAYS_INLINE bool GetSerialArenaFast(SerialArena** arena) {
-    if (GetSerialArenaFromThreadCache(arena)) return true;
+  PROTOBUF_ALWAYS_INLINE bool GetSerialArenaFast(uint64 lifecycle_id,
+                                                 SerialArena** arena) {
+    if (GetSerialArenaFromThreadCache(lifecycle_id, arena)) return true;
+    if (lifecycle_id & kRecordAllocs) return false;
 
     // Check whether we own the last accessed SerialArena on this arena.  This
     // fast path optimizes the case where a single thread uses multiple arenas.
@@ -397,12 +379,12 @@ class PROTOBUF_EXPORT ArenaImpl {
   }
 
   PROTOBUF_ALWAYS_INLINE bool GetSerialArenaFromThreadCache(
-      SerialArena** arena) {
+      uint64 lifecycle_id, SerialArena** arena) {
     // If this thread already owns a block in this arena then try to use that.
     // This fast path optimizes the case where multiple threads allocate from
     // the same arena.
     ThreadCache* tc = &thread_cache();
-    if (PROTOBUF_PREDICT_TRUE(tc->last_lifecycle_id_seen == lifecycle_id_)) {
+    if (PROTOBUF_PREDICT_TRUE(tc->last_lifecycle_id_seen == lifecycle_id)) {
       *arena = tc->last_serial_arena;
       return true;
     }
@@ -410,6 +392,20 @@ class PROTOBUF_EXPORT ArenaImpl {
   }
   SerialArena* GetSerialArenaFallback(void* me);
 
+  template <typename Functor>
+  void PerSerialArena(Functor fn) {
+    // By omitting an Acquire barrier we ensure that any user code that doesn't
+    // properly synchronize Reset() or the destructor will throw a TSAN warning.
+    SerialArena* serial = threads_.load(std::memory_order_relaxed);
+
+    for (; serial; serial = serial->next()) fn(serial);
+  }
+
+  // Releases all memory except the first block which it returns. The first
+  // block might be owned by the user and thus need some extra checks before
+  // deleting.
+  SerialArena::Memory Free(size_t* space_allocated);
+
 #ifdef _MSC_VER
 #pragma warning(disable : 4324)
 #endif
@@ -462,11 +458,11 @@ class PROTOBUF_EXPORT ArenaImpl {
   static ThreadCache& thread_cache() { return thread_cache_; }
 #endif
 
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ArenaImpl);
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ThreadSafeArena);
   // All protos have pointers back to the arena hence Arena must have
   // pointer stability.
-  ArenaImpl(ArenaImpl&&) = delete;
-  ArenaImpl& operator=(ArenaImpl&&) = delete;
+  ThreadSafeArena(ThreadSafeArena&&) = delete;
+  ThreadSafeArena& operator=(ThreadSafeArena&&) = delete;
 
  public:
   // kBlockHeaderSize is sizeof(Block), aligned up to the nearest multiple of 8
@@ -474,8 +470,6 @@ class PROTOBUF_EXPORT ArenaImpl {
   static constexpr size_t kBlockHeaderSize = SerialArena::kBlockHeaderSize;
   static constexpr size_t kSerialArenaSize =
       (sizeof(SerialArena) + 7) & static_cast<size_t>(-8);
-  static constexpr size_t kOptionsSize =
-      (sizeof(Options) + 7) & static_cast<size_t>(-8);
   static_assert(kBlockHeaderSize % 8 == 0,
                 "kBlockHeaderSize must be a multiple of 8.");
   static_assert(kSerialArenaSize % 8 == 0,

src/google/protobuf/arena_unittest.cc

@@ -1331,7 +1331,7 @@ void ClearHookCounts() {
 }  // namespace
 
 // A helper utility class that handles arena callbacks.
-class ArenaOptionsTestFriend : public internal::ArenaMetricsCollector {
+class ArenaOptionsTestFriend final : public internal::ArenaMetricsCollector {
  public:
   static internal::ArenaMetricsCollector* NewWithAllocs() {
     return new ArenaOptionsTestFriend(true);
@@ -1352,7 +1352,7 @@ class ArenaOptionsTestFriend : public internal::ArenaMetricsCollector {
   }
 
   explicit ArenaOptionsTestFriend(bool record_allocs)
-      : record_allocs_(record_allocs) {
+      : ArenaMetricsCollector(record_allocs) {
     ++hooks_num_init;
   }
   void OnDestroy(uint64 space_allocated) override {
@@ -1360,14 +1360,10 @@ class ArenaOptionsTestFriend : public internal::ArenaMetricsCollector {
     delete this;
   }
   void OnReset(uint64 space_allocated) override { ++hooks_num_reset; }
-  bool RecordAllocs() override { return record_allocs_; }
   void OnAlloc(const std::type_info* allocated_type,
                uint64 alloc_size) override {
     ++hooks_num_allocations;
   }
-
- private:
-  bool record_allocs_;
 };
 
 // Test the hooks are correctly called.
@@ -1408,3 +1404,5 @@ TEST(ArenaTest, ArenaHooksWhenAllocationsNotNeeded) {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/arenastring.cc

@@ -252,3 +252,5 @@ void ArenaStringPtr::ClearToDefault(const LazyString& default_value,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/arenastring_unittest.cc

@@ -173,3 +173,5 @@ TEST(ArenaStringPtrTest, ArenaStringPtrOnArenaNoSSO) {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/compiler/command_line_interface.cc

@@ -2018,130 +2018,76 @@ CommandLineInterface::InterpretArgument(const std::string& name,
 
 void CommandLineInterface::PrintHelpText() {
   // Sorry for indentation here; line wrapping would be uglier.
-  std::cout
-      <<
-      "Usage: " << executable_name_
-      << " [OPTION] PROTO_FILES\n"
-         "Parse PROTO_FILES and generate output based on the options given:\n"
-         "  -IPATH, --proto_path=PATH   Specify the directory in which to "
-         "search for\n"
-         "                              imports.  May be specified multiple "
-         "times;\n"
-         "                              directories will be searched in order. "
-         " If not\n"
-         "                              given, the current working directory "
-         "is used.\n"
-         "                              If not found in any of the these "
-         "directories,\n"
-         "                              the --descriptor_set_in descriptors "
-         "will be\n"
-         "                              checked for required proto file.\n"
-         "  --version                   Show version info and exit.\n"
-         "  -h, --help                  Show this text and exit.\n"
-         "  --encode=MESSAGE_TYPE       Read a text-format message of the "
-         "given type\n"
-         "                              from standard input and write it in "
-         "binary\n"
-         "                              to standard output.  The message type "
-         "must\n"
-         "                              be defined in PROTO_FILES or their "
-         "imports.\n"
-         "  --deterministic_output      When using --encode, ensure map fields "
-         "are\n"
-         "                              deterministically ordered. Note that"
-         "this order is not\n"
-         "                              canonical, and changes across builds"
-         "or releases of protoc.\n"
-         "  --decode=MESSAGE_TYPE       Read a binary message of the given "
-         "type from\n"
-         "                              standard input and write it in text "
-         "format\n"
-         "                              to standard output.  The message type "
-         "must\n"
-         "                              be defined in PROTO_FILES or their "
-         "imports.\n"
-         "  --decode_raw                Read an arbitrary protocol message "
-         "from\n"
-         "                              standard input and write the raw "
-         "tag/value\n"
-         "                              pairs in text format to standard "
-         "output.  No\n"
-         "                              PROTO_FILES should be given when using "
-         "this\n"
-         "                              flag.\n"
-         "  --descriptor_set_in=FILES   Specifies a delimited list of FILES\n"
-         "                              each containing a FileDescriptorSet "
-         "(a\n"
-         "                              protocol buffer defined in "
-         "descriptor.proto).\n"
-         "                              The FileDescriptor for each of the "
-         "PROTO_FILES\n"
-         "                              provided will be loaded from these\n"
-         "                              FileDescriptorSets. If a "
-         "FileDescriptor\n"
-         "                              appears multiple times, the first "
-         "occurrence\n"
-         "                              will be used.\n"
-         "  -oFILE,                     Writes a FileDescriptorSet (a protocol "
-         "buffer,\n"
-         "    --descriptor_set_out=FILE defined in descriptor.proto) "
-         "containing all of\n"
-         "                              the input files to FILE.\n"
-         "  --include_imports           When using --descriptor_set_out, also "
-         "include\n"
-         "                              all dependencies of the input files in "
-         "the\n"
-         "                              set, so that the set is "
-         "self-contained.\n"
-         "  --include_source_info       When using --descriptor_set_out, do "
-         "not strip\n"
-         "                              SourceCodeInfo from the "
-         "FileDescriptorProto.\n"
-         "                              This results in vastly larger "
-         "descriptors that\n"
-         "                              include information about the "
-         "original\n"
-         "                              location of each decl in the source "
-         "file as\n"
-         "                              well as surrounding comments.\n"
-         "  --dependency_out=FILE       Write a dependency output file in the "
-         "format\n"
-         "                              expected by make. This writes the "
-         "transitive\n"
-         "                              set of input file paths to FILE\n"
-         "  --error_format=FORMAT       Set the format in which to print "
-         "errors.\n"
-         "                              FORMAT may be 'gcc' (the default) or "
-         "'msvs'\n"
-         "                              (Microsoft Visual Studio format).\n"
-         "  --print_free_field_numbers  Print the free field numbers of the "
-         "messages\n"
-         "                              defined in the given proto files. "
-         "Groups share\n"
-         "                              the same field number space with the "
-         "parent \n"
-         "                              message. Extension ranges are counted "
-         "as \n"
-         "                              occupied fields numbers.\n"
-      << std::endl;
+  std::cout << "Usage: " << executable_name_ << " [OPTION] PROTO_FILES";
+  std::cout << R"(
+Parse PROTO_FILES and generate output based on the options given:
+  -IPATH, --proto_path=PATH   Specify the directory in which to search for
+                              imports.  May be specified multiple times;
+                              directories will be searched in order.  If not
+                              given, the current working directory is used.
+                              If not found in any of the these directories,
+                              the --descriptor_set_in descriptors will be
+                              checked for required proto file.
+  --version                   Show version info and exit.
+  -h, --help                  Show this text and exit.
+  --encode=MESSAGE_TYPE       Read a text-format message of the given type
+                              from standard input and write it in binary
+                              to standard output.  The message type must
+                              be defined in PROTO_FILES or their imports.
+  --deterministic_output      When using --encode, ensure map fields are
+                              deterministically ordered. Note that this order
+                              is not canonical, and changes across builds or
+                              releases of protoc.
+  --decode=MESSAGE_TYPE       Read a binary message of the given type from
+                              standard input and write it in text format
+                              to standard output.  The message type must
+                              be defined in PROTO_FILES or their imports.
+  --decode_raw                Read an arbitrary protocol message from
+                              standard input and write the raw tag/value
+                              pairs in text format to standard output.  No
+                              PROTO_FILES should be given when using this
+                              flag.
+  --descriptor_set_in=FILES   Specifies a delimited list of FILES
+                              each containing a FileDescriptorSet (a
+                              protocol buffer defined in descriptor.proto).
+                              The FileDescriptor for each of the PROTO_FILES
+                              provided will be loaded from these
+                              FileDescriptorSets. If a FileDescriptor
+                              appears multiple times, the first occurrence
+                              will be used.
+  -oFILE,                     Writes a FileDescriptorSet (a protocol buffer,
+    --descriptor_set_out=FILE defined in descriptor.proto) containing all of
+                              the input files to FILE.
+  --include_imports           When using --descriptor_set_out, also include
+                              all dependencies of the input files in the
+                              set, so that the set is self-contained.
+  --include_source_info       When using --descriptor_set_out, do not strip
+                              SourceCodeInfo from the FileDescriptorProto.
+                              This results in vastly larger descriptors that
+                              include information about the original
+                              location of each decl in the source file as
+                              well as surrounding comments.
+  --dependency_out=FILE       Write a dependency output file in the format
+                              expected by make. This writes the transitive
+                              set of input file paths to FILE
+  --error_format=FORMAT       Set the format in which to print errors.
+                              FORMAT may be 'gcc' (the default) or 'msvs'
+                              (Microsoft Visual Studio format).
+  --print_free_field_numbers  Print the free field numbers of the messages
+                              defined in the given proto files. Groups share
+                              the same field number space with the parent
+                              message. Extension ranges are counted as
+                              occupied fields numbers.)";
   if (!plugin_prefix_.empty()) {
-    std::cout
-        << "  --plugin=EXECUTABLE         Specifies a plugin executable to "
-           "use.\n"
-           "                              Normally, protoc searches the PATH "
-           "for\n"
-           "                              plugins, but you may specify "
-           "additional\n"
-           "                              executables not in the path using "
-           "this flag.\n"
-           "                              Additionally, EXECUTABLE may be of "
-           "the form\n"
-           "                              NAME=PATH, in which case the given "
-           "plugin name\n"
-           "                              is mapped to the given executable "
-           "even if\n"
-           "                              the executable's own name differs."
-        << std::endl;
+    std::cout << R"(
+  --plugin=EXECUTABLE         Specifies a plugin executable to use.
+                              Normally, protoc searches the PATH for
+                              plugins, but you may specify additional
+                              executables not in the path using this flag.
+                              Additionally, EXECUTABLE may be of the form
+                              NAME=PATH, in which case the given plugin name
+                              is mapped to the given executable even if
+                              the executable's own name differs.)";
   }
 
   for (GeneratorMap::iterator iter = generators_by_flag_name_.begin();
@@ -2149,35 +2095,26 @@ void CommandLineInterface::PrintHelpText() {
     // FIXME(kenton):  If the text is long enough it will wrap, which is ugly,
     //   but fixing this nicely (e.g. splitting on spaces) is probably more
     //   trouble than it's worth.
-    std::cout << "  " << iter->first << "=OUT_DIR "
+    std::cout << std::endl
+              << "  " << iter->first << "=OUT_DIR "
               << std::string(19 - iter->first.size(),
                              ' ')  // Spaces for alignment.
-              << iter->second.help_text << std::endl;
-  }
-  std::cout << "  @<filename>                 Read options and filenames from "
-               "file. If a\n"
-               "                              relative file path is specified, "
-               "the file\n"
-               "                              will be searched in the working "
-               "directory.\n"
-               "                              The --proto_path option will not "
-               "affect how\n"
-               "                              this argument file is searched. "
-               "Content of\n"
-               "                              the file will be expanded in the "
-               "position of\n"
-               "                              @<filename> as in the argument "
-               "list. Note\n"
-               "                              that shell expansion is not "
-               "applied to the\n"
-               "                              content of the file (i.e., you "
-               "cannot use\n"
-               "                              quotes, wildcards, escapes, "
-               "commands, etc.).\n"
-               "                              Each line corresponds to a "
-               "single argument,\n"
-               "                              even if it contains spaces."
-            << std::endl;
+              << iter->second.help_text;
+  }
+  std::cout << R"(
+  @<filename>                 Read options and filenames from file. If a
+                              relative file path is specified, the file
+                              will be searched in the working directory.
+                              The --proto_path option will not affect how
+                              this argument file is searched. Content of
+                              the file will be expanded in the position of
+                              @<filename> as in the argument list. Note
+                              that shell expansion is not applied to the
+                              content of the file (i.e., you cannot use
+                              quotes, wildcards, escapes, commands, etc.).
+                              Each line corresponds to a single argument,
+                              even if it contains spaces.)";
+  std::cout << std::endl;
 }
 
 bool CommandLineInterface::EnforceProto3OptionalSupport(

src/google/protobuf/compiler/cpp/cpp_extension.cc

@@ -99,8 +99,7 @@ ExtensionGenerator::ExtensionGenerator(const FieldDescriptor* descriptor,
   std::string scope =
       IsScoped() ? ClassName(descriptor_->extension_scope(), false) + "::" : "";
   variables_["scope"] = scope;
-  std::string scoped_name = scope + ResolveKeyword(name);
-  variables_["scoped_name"] = scoped_name;
+  variables_["scoped_name"] = ExtensionName(descriptor_);
   variables_["number"] = StrCat(descriptor_->number());
 }
 
@@ -175,6 +174,7 @@ void ExtensionGenerator::GenerateDefinition(io::Printer* printer) {
   }
 
   format(
+      "PROTOBUF_ATTRIBUTE_INIT_PRIORITY "
       "::$proto_ns$::internal::ExtensionIdentifier< $extendee$,\n"
       "    ::$proto_ns$::internal::$type_traits$, $field_type$, $packed$ >\n"
       "  $scoped_name$($constant_name$, $1$);\n",

src/google/protobuf/compiler/cpp/cpp_file.cc

@@ -429,6 +429,12 @@ void FileGenerator::GenerateSourceIncludes(io::Printer* printer) {
 
   format("// @@protoc_insertion_point(includes)\n");
   IncludeFile("net/proto2/public/port_def.inc", printer);
+
+  // For MSVC builds, we use #pragma init_seg to move the initialization of our
+  // libraries to happen before the user code.
+  // This worksaround the fact that MSVC does not do constant initializers when
+  // required by the standard.
+  format("\nPROTOBUF_PRAGMA_INIT_SEG\n");
 }
 
 void FileGenerator::GenerateSourceDefaultInstance(int idx,
@@ -916,8 +922,9 @@ void FileGenerator::GenerateReflectionInitializationCode(io::Printer* printer) {
   if (file_->name() != "net/proto2/proto/descriptor.proto") {
     format(
         "// Force running AddDescriptors() at dynamic initialization time.\n"
-        "static bool $1$ = (static_cast<void>("
-        "::$proto_ns$::internal::AddDescriptors(&$desc_table$)), true);\n",
+        "PROTOBUF_ATTRIBUTE_INIT_PRIORITY "
+        "static ::$proto_ns$::internal::AddDescriptorsRunner "
+        "$1$(&$desc_table$);\n",
         UniqueName("dynamic_init_dummy", file_, options_));
   }
 }

src/google/protobuf/compiler/cpp/cpp_helpers.cc

@@ -362,10 +362,16 @@ std::string QualifiedClassName(const EnumDescriptor* d) {
   return QualifiedClassName(d, Options());
 }
 
+std::string ExtensionName(const FieldDescriptor* d) {
+  if (const Descriptor* scope = d->extension_scope())
+    return StrCat(ClassName(scope), "::", ResolveKeyword(d->name()));
+  return ResolveKeyword(d->name());
+}
+
 std::string QualifiedExtensionName(const FieldDescriptor* d,
                                    const Options& options) {
   GOOGLE_DCHECK(d->is_extension());
-  return QualifiedFileLevelSymbol(d->file(), FieldName(d), options);
+  return QualifiedFileLevelSymbol(d->file(), ExtensionName(d), options);
 }
 
 std::string QualifiedExtensionName(const FieldDescriptor* d) {

src/google/protobuf/compiler/cpp/cpp_helpers.h

@@ -134,6 +134,10 @@ inline std::string ClassName(const EnumDescriptor* descriptor, bool qualified) {
                    : ClassName(descriptor);
 }
 
+// Returns the extension name prefixed with the class name if nested but without
+// the package name.
+std::string ExtensionName(const FieldDescriptor* d);
+
 std::string QualifiedExtensionName(const FieldDescriptor* d,
                                    const Options& options);
 std::string QualifiedExtensionName(const FieldDescriptor* d);

src/google/protobuf/compiler/cpp/cpp_message.cc

@@ -308,12 +308,7 @@ bool ShouldMarkIsInitializedAsFinal(const Descriptor* descriptor,
 
 bool ShouldMarkNewAsFinal(const Descriptor* descriptor,
                           const Options& options) {
-  static std::set<std::string> exclusions{
-  };
-
-  const std::string name = ClassName(descriptor, true);
-  return exclusions.find(name) == exclusions.end() ||
-         options.opensource_runtime;
+  return true;
 }
 
 // Returns true to make the message serialize in order, decided by the following
@@ -1232,13 +1227,13 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
         "\n");
     if (HasDescriptorMethods(descriptor_->file(), options_)) {
       format(
-          "void PackFrom(const ::$proto_ns$::Message& message) {\n"
-          "  _any_metadata_.PackFrom(message);\n"
+          "bool PackFrom(const ::$proto_ns$::Message& message) {\n"
+          "  return _any_metadata_.PackFrom(message);\n"
           "}\n"
-          "void PackFrom(const ::$proto_ns$::Message& message,\n"
+          "bool PackFrom(const ::$proto_ns$::Message& message,\n"
           "              ::PROTOBUF_NAMESPACE_ID::ConstStringParam "
           "type_url_prefix) {\n"
-          "  _any_metadata_.PackFrom(message, type_url_prefix);\n"
+          "  return _any_metadata_.PackFrom(message, type_url_prefix);\n"
           "}\n"
           "bool UnpackTo(::$proto_ns$::Message* message) const {\n"
           "  return _any_metadata_.UnpackTo(message);\n"
@@ -1250,16 +1245,16 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
           "template <typename T, class = typename std::enable_if<"
           "!std::is_convertible<T, const ::$proto_ns$::Message&>"
           "::value>::type>\n"
-          "void PackFrom(const T& message) {\n"
-          "  _any_metadata_.PackFrom<T>(message);\n"
+          "bool PackFrom(const T& message) {\n"
+          "  return _any_metadata_.PackFrom<T>(message);\n"
           "}\n"
           "template <typename T, class = typename std::enable_if<"
           "!std::is_convertible<T, const ::$proto_ns$::Message&>"
           "::value>::type>\n"
-          "void PackFrom(const T& message,\n"
+          "bool PackFrom(const T& message,\n"
           "              ::PROTOBUF_NAMESPACE_ID::ConstStringParam "
           "type_url_prefix) {\n"
-          "  _any_metadata_.PackFrom<T>(message, type_url_prefix);"
+          "  return _any_metadata_.PackFrom<T>(message, type_url_prefix);"
           "}\n"
           "template <typename T, class = typename std::enable_if<"
           "!std::is_convertible<T, const ::$proto_ns$::Message&>"
@@ -1270,14 +1265,14 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
     } else {
       format(
           "template <typename T>\n"
-          "void PackFrom(const T& message) {\n"
-          "  _any_metadata_.PackFrom(message);\n"
+          "bool PackFrom(const T& message) {\n"
+          "  return _any_metadata_.PackFrom(message);\n"
           "}\n"
           "template <typename T>\n"
-          "void PackFrom(const T& message,\n"
+          "bool PackFrom(const T& message,\n"
           "              ::PROTOBUF_NAMESPACE_ID::ConstStringParam "
           "type_url_prefix) {\n"
-          "  _any_metadata_.PackFrom(message, type_url_prefix);\n"
+          "  return _any_metadata_.PackFrom(message, type_url_prefix);\n"
           "}\n"
           "template <typename T>\n"
           "bool UnpackTo(T* message) const {\n"
@@ -2464,7 +2459,8 @@ void MessageGenerator::GenerateConstructorBody(io::Printer* printer,
   } else {
     pod_template =
         "::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(\n"
-        "    reinterpret_cast<char*>(&$first$_) - reinterpret_cast<char*>(this)),\n"
+        "    reinterpret_cast<char*>(&$first$_) - "
+        "reinterpret_cast<char*>(this)),\n"
         "    0, static_cast<size_t>(reinterpret_cast<char*>(&$last$_) -\n"
         "    reinterpret_cast<char*>(&$first$_)) + sizeof($last$_));\n";
   }
@@ -3603,29 +3599,17 @@ void MessageGenerator::GenerateSerializeWithCachedSizesBodyShuffled(
         "_weak_field_map_);\n");
   }
 
-  format(
-      "static const int kStart = GetInvariantPerBuild($1$UL) % $2$;\n"
-      "bool first_pass = true;\n"
-      "for (int i = kStart; i != kStart || first_pass; i = ((i + $3$) % $2$)) "
-      "{\n",
-      0,
-      num_fields, kLargePrime);
+  format("for (int i = $1$; i >= 0; i-- ) {\n", num_fields - 1);
 
   format.Indent();
   format("switch(i) {\n");
   format.Indent();
 
-  bool first_pass_set = false;
   int index = 0;
   for (const auto* f : ordered_fields) {
     format("case $1$: {\n", index++);
     format.Indent();
 
-    if (!first_pass_set) {
-      first_pass_set = true;
-      format("first_pass = false;\n");
-    }
-
     GenerateSerializeOneField(printer, f, -1);
 
     format("break;\n");
@@ -3637,11 +3621,6 @@ void MessageGenerator::GenerateSerializeWithCachedSizesBodyShuffled(
     format("case $1$: {\n", index++);
     format.Indent();
 
-    if (!first_pass_set) {
-      first_pass_set = true;
-      format("first_pass = false;\n");
-    }
-
     GenerateSerializeOneExtensionRange(printer, r);
 
     format("break;\n");

src/google/protobuf/compiler/java/java_helpers.cc

@@ -89,6 +89,17 @@ const std::unordered_set<std::string>* kReservedNames =
         "transient",  "try",          "void",      "volatile",   "while",
     });
 
+// Names that should be avoided as field names in Kotlin.
+// All Kotlin hard keywords are in this list.
+const std::unordered_set<std::string>* kKotlinForbiddenNames =
+    new std::unordered_set<std::string>({
+        "as",    "as?",   "break", "class",  "continue",  "do",     "else",
+        "false", "for",   "fun",   "if",     "in",        "!in",    "interface",
+        "is",    "!is",   "null",  "object", "package",   "return", "super",
+        "this",  "throw", "true",  "try",    "typealias", "typeof", "val",
+        "var",   "when",  "while",
+    });
+
 bool IsForbidden(const std::string& field_name) {
   for (int i = 0; i < GOOGLE_ARRAYSIZE(kForbiddenWordList); ++i) {
     if (field_name == kForbiddenWordList[i]) {
@@ -215,6 +226,7 @@ std::string UnderscoresToCamelCaseCheckReserved(const FieldDescriptor* field) {
   return name;
 }
 
+
 std::string UniqueFileScopeIdentifier(const Descriptor* descriptor) {
   return "static_" + StringReplace(descriptor->full_name(), ".", "_", true);
 }

src/google/protobuf/compiler/java/java_helpers.h

@@ -51,6 +51,7 @@ namespace java {
 extern const char kThickSeparator[];
 extern const char kThinSeparator[];
 
+
 // If annotation_file is non-empty, prints a javax.annotation.Generated
 // annotation to the given Printer. annotation_file will be referenced in the
 // annotation's comments field. delimiter should be the Printer's delimiter

src/google/protobuf/compiler/java/java_name_resolver.cc

@@ -68,6 +68,7 @@ std::string ClassNameWithoutPackage(const Descriptor* descriptor,
   return StripPackageName(descriptor->full_name(), descriptor->file());
 }
 
+
 // Get the name of an enum's Java class without package name prefix.
 std::string ClassNameWithoutPackage(const EnumDescriptor* descriptor,
                                     bool immutable) {

src/google/protobuf/compiler/js/js_generator.cc

@@ -3162,8 +3162,7 @@ void Generator::GenerateClassDeserializeBinaryField(
           "fieldtype",
           JSFieldTypeAnnotation(options, field, false, true,
                                 /* singular_if_not_packed */ false, BYTES_U8),
-          "reader",
-          JSBinaryReaderMethodType(field));
+          "reader", JSBinaryReaderMethodType(field));
     } else {
       printer->Print(
           "      var value = /** @type {$fieldtype$} */ "
@@ -3179,7 +3178,8 @@ void Generator::GenerateClassDeserializeBinaryField(
       printer->Print(
           "      for (var i = 0; i < values.length; i++) {\n"
           "        msg.add$name$(values[i]);\n"
-          "      }\n", "name",
+          "      }\n",
+          "name",
           JSGetterName(options, field, BYTES_DEFAULT, /* drop_list = */ true));
     } else if (field->is_repeated()) {
       printer->Print(

src/google/protobuf/compiler/plugin.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fdescriptor_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<6> scc_info_FileDescriptorProto_google_2fprotobuf_2fdescriptor_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fdescriptor_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_GeneratedCodeInfo_google_2fprotobuf_2fdescriptor_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fcompiler_2fplugin_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_CodeGeneratorResponse_File_google_2fprotobuf_2fcompiler_2fplugin_2eproto;
@@ -204,7 +206,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fcompiler_2fplugin_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fcompiler_2fplugin_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fcompiler_2fplugin_2eproto(&descriptor_table_google_2fprotobuf_2fcompiler_2fplugin_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 namespace compiler {
 const ::PROTOBUF_NAMESPACE_ID::EnumDescriptor* CodeGeneratorResponse_Feature_descriptor() {

src/google/protobuf/descriptor.cc

@@ -855,15 +855,15 @@ void DescriptorPool::Tables::RollbackToLastCheckpoint() {
   GOOGLE_DCHECK(!checkpoints_.empty());
   const CheckPoint& checkpoint = checkpoints_.back();
 
-  for (int i = checkpoint.pending_symbols_before_checkpoint;
+  for (size_t i = checkpoint.pending_symbols_before_checkpoint;
        i < symbols_after_checkpoint_.size(); i++) {
     symbols_by_name_.erase(symbols_after_checkpoint_[i]);
   }
-  for (int i = checkpoint.pending_files_before_checkpoint;
+  for (size_t i = checkpoint.pending_files_before_checkpoint;
        i < files_after_checkpoint_.size(); i++) {
     files_by_name_.erase(files_after_checkpoint_[i]);
   }
-  for (int i = checkpoint.pending_extensions_before_checkpoint;
+  for (size_t i = checkpoint.pending_extensions_before_checkpoint;
        i < extensions_after_checkpoint_.size(); i++) {
     extensions_.erase(extensions_after_checkpoint_[i]);
   }
@@ -4203,13 +4203,13 @@ void DescriptorBuilder::AllocateOptionsImpl(
 void DescriptorBuilder::AddRecursiveImportError(
     const FileDescriptorProto& proto, int from_here) {
   std::string error_message("File recursively imports itself: ");
-  for (int i = from_here; i < tables_->pending_files_.size(); i++) {
+  for (size_t i = from_here; i < tables_->pending_files_.size(); i++) {
     error_message.append(tables_->pending_files_[i]);
     error_message.append(" -> ");
   }
   error_message.append(proto.name());
 
-  if (from_here < tables_->pending_files_.size() - 1) {
+  if (static_cast<size_t>(from_here) < tables_->pending_files_.size() - 1) {
     AddError(tables_->pending_files_[from_here + 1], proto,
              DescriptorPool::ErrorCollector::IMPORT, error_message);
   } else {
@@ -4282,7 +4282,7 @@ const FileDescriptor* DescriptorBuilder::BuildFile(
   //   mid-file, but that's pretty ugly, and I'm pretty sure there are
   //   some languages out there that do not allow recursive dependencies
   //   at all.
-  for (int i = 0; i < tables_->pending_files_.size(); i++) {
+  for (size_t i = 0; i < tables_->pending_files_.size(); i++) {
     if (tables_->pending_files_[i] == proto.name()) {
       AddRecursiveImportError(proto, i);
       return nullptr;
@@ -6702,10 +6702,10 @@ void DescriptorBuilder::OptionInterpreter::UpdateSourceCodeInfo(
     if (matched) {
       // see if this location is in the range to remove
       bool loc_matches = true;
-      if (loc->path_size() < pathv.size()) {
+      if (loc->path_size() < static_cast<int64>(pathv.size())) {
         loc_matches = false;
       } else {
-        for (int j = 0; j < pathv.size(); j++) {
+        for (size_t j = 0; j < pathv.size(); j++) {
           if (loc->path(j) != pathv[j]) {
             loc_matches = false;
             break;
@@ -7444,3 +7444,5 @@ void LazyDescriptor::OnceInternal() {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/descriptor.h

@@ -1491,7 +1491,8 @@ class PROTOBUF_EXPORT FileDescriptor {
   Syntax syntax() const;
   static const char* SyntaxName(Syntax syntax);
 
-  // Find a top-level message type by name.  Returns nullptr if not found.
+  // Find a top-level message type by name (not full_name).  Returns nullptr if
+  // not found.
   const Descriptor* FindMessageTypeByName(ConstStringParam name) const;
   // Find a top-level enum type by name.  Returns nullptr if not found.
   const EnumDescriptor* FindEnumTypeByName(ConstStringParam name) const;

src/google/protobuf/descriptor.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fdescriptor_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<6> scc_info_DescriptorProto_google_2fprotobuf_2fdescriptor_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fdescriptor_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_DescriptorProto_ExtensionRange_google_2fprotobuf_2fdescriptor_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fdescriptor_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<0> scc_info_DescriptorProto_ReservedRange_google_2fprotobuf_2fdescriptor_2eproto;
@@ -1174,7 +1176,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fdescriptor_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fdescriptor_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fdescriptor_2eproto(&descriptor_table_google_2fprotobuf_2fdescriptor_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 const ::PROTOBUF_NAMESPACE_ID::EnumDescriptor* FieldDescriptorProto_Type_descriptor() {
   ::PROTOBUF_NAMESPACE_ID::internal::AssignDescriptors(&descriptor_table_google_2fprotobuf_2fdescriptor_2eproto);

src/google/protobuf/descriptor_database.cc

@@ -962,14 +962,14 @@ bool MergedDescriptorDatabase::FindFileByName(const std::string& filename,
 
 bool MergedDescriptorDatabase::FindFileContainingSymbol(
     const std::string& symbol_name, FileDescriptorProto* output) {
-  for (int i = 0; i < sources_.size(); i++) {
+  for (size_t i = 0; i < sources_.size(); i++) {
     if (sources_[i]->FindFileContainingSymbol(symbol_name, output)) {
       // The symbol was found in source i.  However, if one of the previous
       // sources defines a file with the same name (which presumably doesn't
       // contain the symbol, since it wasn't found in that source), then we
       // must hide it from the caller.
       FileDescriptorProto temp;
-      for (int j = 0; j < i; j++) {
+      for (size_t j = 0; j < i; j++) {
         if (sources_[j]->FindFileByName(output->name(), &temp)) {
           // Found conflicting file in a previous source.
           return false;
@@ -984,7 +984,7 @@ bool MergedDescriptorDatabase::FindFileContainingSymbol(
 bool MergedDescriptorDatabase::FindFileContainingExtension(
     const std::string& containing_type, int field_number,
     FileDescriptorProto* output) {
-  for (int i = 0; i < sources_.size(); i++) {
+  for (size_t i = 0; i < sources_.size(); i++) {
     if (sources_[i]->FindFileContainingExtension(containing_type, field_number,
                                                  output)) {
       // The symbol was found in source i.  However, if one of the previous
@@ -992,7 +992,7 @@ bool MergedDescriptorDatabase::FindFileContainingExtension(
       // contain the symbol, since it wasn't found in that source), then we
       // must hide it from the caller.
       FileDescriptorProto temp;
-      for (int j = 0; j < i; j++) {
+      for (size_t j = 0; j < i; j++) {
         if (sources_[j]->FindFileByName(output->name(), &temp)) {
           // Found conflicting file in a previous source.
           return false;

src/google/protobuf/descriptor_unittest.cc

@@ -1851,12 +1851,17 @@ class ExtensionDescriptorTest : public testing::Test {
     //     extensions 10 to 19;
     //     extensions 30 to 39;
     //   }
-    //   extends Foo with optional int32 foo_int32 = 10;
-    //   extends Foo with repeated TestEnum foo_enum = 19;
+    //   extend Foo {
+    //     optional int32 foo_int32 = 10;
+    //   }
+    //   extend Foo {
+    //     repeated TestEnum foo_enum = 19;
+    //   }
     //   message Bar {
-    //     extends Foo with optional Qux foo_message = 30;
-    //     // (using Qux as the group type)
-    //     extends Foo with repeated group foo_group = 39;
+    //     extend Foo {
+    //       optional Qux foo_message = 30;
+    //       repeated Qux foo_group = 39;  // (but internally set to TYPE_GROUP)
+    //     }
     //   }
 
     FileDescriptorProto foo_file;
@@ -8110,3 +8115,5 @@ TEST_F(LazilyBuildDependenciesTest, Dependency) {
 }  // namespace descriptor_unittest
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/duration.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class DurationDefaultTypeInternal {
  public:
@@ -76,7 +78,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fduration_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fduration_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fduration_2eproto(&descriptor_table_google_2fprotobuf_2fduration_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/dynamic_message.cc

@@ -509,7 +509,7 @@ DynamicMessage::~DynamicMessage() {
       void* field_ptr =
           OffsetToPointer(type_info_->oneof_case_offset +
                           sizeof(uint32) * field->containing_oneof()->index());
-      if (*(reinterpret_cast<const uint32*>(field_ptr)) == field->number()) {
+      if (*(reinterpret_cast<const int32*>(field_ptr)) == field->number()) {
         field_ptr = OffsetToPointer(
             type_info_->offsets[descriptor->field_count() +
                                 field->containing_oneof()->index()]);

src/google/protobuf/empty.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class EmptyDefaultTypeInternal {
  public:
@@ -73,7 +75,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fempty_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fempty_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fempty_2eproto(&descriptor_table_google_2fprotobuf_2fempty_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/extension_set.cc

@@ -180,7 +180,6 @@ void ExtensionSet::RegisterMessageExtension(const MessageLite* containing_type,
   Register(containing_type, number, info);
 }
 
-
 // ===================================================================
 // Constructors and basic methods.
 
@@ -2141,3 +2140,5 @@ size_t ExtensionSet::MessageSetByteSize() const {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/extension_set.h

@@ -1328,7 +1328,9 @@ RepeatedMessageTypeTraits<Type>::GetDefaultRepeatedField() {
 // ExtensionIdentifier
 
 // This is the type of actual extension objects.  E.g. if you have:
-//   extends Foo with optional int32 bar = 1234;
+//   extend Foo {
+//     optional int32 bar = 1234;
+//   }
 // then "bar" will be defined in C++ as:
 //   ExtensionIdentifier<Foo, PrimitiveTypeTraits<int32>, 5, false> bar(1234);
 //

src/google/protobuf/extension_set_heavy.cc

@@ -534,3 +534,5 @@ bool ExtensionSet::ParseMessageSetItem(io::CodedInputStream* input,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/extension_set_unittest.cc

@@ -1335,3 +1335,5 @@ TEST(ExtensionSetTest, ConstInit) {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/field_mask.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class FieldMaskDefaultTypeInternal {
  public:
@@ -75,7 +77,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2ffield_5fmask_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2ffield_5fmask_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2ffield_5fmask_2eproto(&descriptor_table_google_2fprotobuf_2ffield_5fmask_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/generated_enum_util.cc

@@ -83,7 +83,7 @@ int LookUpEnumName(const EnumEntry* enums, const int* sorted_indices,
 bool InitializeEnumStrings(
     const EnumEntry* enums, const int* sorted_indices, size_t size,
     internal::ExplicitlyConstructed<std::string>* enum_strings) {
-  for (int i = 0; i < size; ++i) {
+  for (size_t i = 0; i < size; ++i) {
     enum_strings[i].Construct(enums[sorted_indices[i]].name);
     internal::OnShutdownDestroyString(enum_strings[i].get_mutable());
   }

src/google/protobuf/generated_message_reflection.cc

@@ -836,7 +836,7 @@ void Reflection::ClearField(Message* message,
         }
 
         case FieldDescriptor::CPPTYPE_MESSAGE:
-          if (schema_.HasBitIndex(field) == -1) {
+          if (schema_.HasBitIndex(field) == static_cast<uint32>(-1)) {
             // Proto3 does not have has-bits and we need to set a message field
             // to nullptr in order to indicate its un-presence.
             if (GetArena(message) == nullptr) {
@@ -1046,7 +1046,8 @@ void Reflection::ListFieldsMayFailOnStripped(
       schema_.HasHasbits() ? GetHasBits(message) : nullptr;
   const uint32* const has_bits_indices = schema_.has_bit_indices_;
   output->reserve(descriptor_->field_count());
-  for (int i = 0; i <= last_non_weak_field_index_; i++) {
+  const int last_non_weak_field_index = last_non_weak_field_index_;
+  for (int i = 0; i <= last_non_weak_field_index; i++) {
     const FieldDescriptor* field = descriptor_->field(i);
     if (!should_fail && schema_.IsFieldStripped(field)) {
       continue;
@@ -1061,10 +1062,11 @@ void Reflection::ListFieldsMayFailOnStripped(
         const uint32* const oneof_case_array = GetConstPointerAtOffset<uint32>(
             &message, schema_.oneof_case_offset_);
         // Equivalent to: HasOneofField(message, field)
-        if (oneof_case_array[containing_oneof->index()] == field->number()) {
+        if (static_cast<int64>(oneof_case_array[containing_oneof->index()]) ==
+            field->number()) {
           output->push_back(field);
         }
-      } else if (has_bits && has_bits_indices[i] != -1) {
+      } else if (has_bits && has_bits_indices[i] != static_cast<uint32>(-1)) {
         CheckInvalidAccess(schema_, field);
         // Equivalent to: HasBit(message, field)
         if (IsIndexInHasBitSet(has_bits, has_bits_indices[i])) {
@@ -2005,7 +2007,7 @@ InternalMetadata* Reflection::MutableInternalMetadata(Message* message) const {
 bool Reflection::HasBit(const Message& message,
                         const FieldDescriptor* field) const {
   GOOGLE_DCHECK(!field->options().weak());
-  if (schema_.HasBitIndex(field) != -1) {
+  if (schema_.HasBitIndex(field) != static_cast<uint32>(-1)) {
     return IsIndexInHasBitSet(GetHasBits(message), schema_.HasBitIndex(field));
   }
 
@@ -2064,7 +2066,7 @@ bool Reflection::HasBit(const Message& message,
 void Reflection::SetBit(Message* message, const FieldDescriptor* field) const {
   GOOGLE_DCHECK(!field->options().weak());
   const uint32 index = schema_.HasBitIndex(field);
-  if (index == -1) return;
+  if (index == static_cast<uint32>(-1)) return;
   MutableHasBits(message)[index / 32] |=
       (static_cast<uint32>(1) << (index % 32));
 }
@@ -2073,7 +2075,7 @@ void Reflection::ClearBit(Message* message,
                           const FieldDescriptor* field) const {
   GOOGLE_DCHECK(!field->options().weak());
   const uint32 index = schema_.HasBitIndex(field);
-  if (index == -1) return;
+  if (index == static_cast<uint32>(-1)) return;
   MutableHasBits(message)[index / 32] &=
       ~(static_cast<uint32>(1) << (index % 32));
 }
@@ -2107,7 +2109,8 @@ bool Reflection::HasOneof(const Message& message,
 
 bool Reflection::HasOneofField(const Message& message,
                                const FieldDescriptor* field) const {
-  return (GetOneofCase(message, field->containing_oneof()) == field->number());
+  return (GetOneofCase(message, field->containing_oneof()) ==
+          static_cast<uint32>(field->number()));
 }
 
 void Reflection::SetOneofCase(Message* message,
@@ -2416,6 +2419,8 @@ struct MetadataOwner {
   std::vector<std::pair<const Metadata*, const Metadata*> > metadata_arrays_;
 };
 
+void AddDescriptors(const DescriptorTable* table);
+
 void AssignDescriptorsImpl(const DescriptorTable* table, bool eager) {
   // Ensure the file descriptor is added to the pool.
   {
@@ -2493,6 +2498,16 @@ void AddDescriptorsImpl(const DescriptorTable* table) {
   MessageFactory::InternalRegisterGeneratedFile(table);
 }
 
+void AddDescriptors(const DescriptorTable* table) {
+  // AddDescriptors is not thread safe. Callers need to ensure calls are
+  // properly serialized. This function is only called pre-main by global
+  // descriptors and we can assume single threaded access or it's called
+  // by AssignDescriptorImpl which uses a mutex to sequence calls.
+  if (table->is_initialized) return;
+  table->is_initialized = true;
+  AddDescriptorsImpl(table);
+}
+
 }  // namespace
 
 // Separate function because it needs to be a friend of
@@ -2513,14 +2528,8 @@ void AssignDescriptors(const DescriptorTable* table, bool eager) {
   call_once(*table->once, AssignDescriptorsImpl, table, eager);
 }
 
-void AddDescriptors(const DescriptorTable* table) {
-  // AddDescriptors is not thread safe. Callers need to ensure calls are
-  // properly serialized. This function is only called pre-main by global
-  // descriptors and we can assume single threaded access or it's called
-  // by AssignDescriptorImpl which uses a mutex to sequence calls.
-  if (table->is_initialized) return;
-  table->is_initialized = true;
-  AddDescriptorsImpl(table);
+AddDescriptorsRunner::AddDescriptorsRunner(const DescriptorTable* table) {
+  AddDescriptors(table);
 }
 
 void RegisterFileLevelMetadata(const DescriptorTable* table) {
@@ -2544,3 +2553,5 @@ void UnknownFieldSetSerializer(const uint8* base, uint32 offset, uint32 tag,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/generated_message_reflection.h

@@ -291,18 +291,15 @@ enum {
 void PROTOBUF_EXPORT AssignDescriptors(const DescriptorTable* table,
                                        bool eager = false);
 
-// AddDescriptors() is a file-level procedure which adds the encoded
-// FileDescriptorProto for this .proto file to the global DescriptorPool for
-// generated files (DescriptorPool::generated_pool()). It ordinarily runs at
-// static initialization time, but is not used at all in LITE_RUNTIME mode.
-// AddDescriptors() is *not* thread-safe.
-void PROTOBUF_EXPORT AddDescriptors(const DescriptorTable* table);
-
 // These cannot be in lite so we put them in the reflection.
 PROTOBUF_EXPORT void UnknownFieldSetSerializer(const uint8* base, uint32 offset,
                                                uint32 tag, uint32 has_offset,
                                                io::CodedOutputStream* output);
 
+struct PROTOBUF_EXPORT AddDescriptorsRunner {
+  explicit AddDescriptorsRunner(const DescriptorTable* table);
+};
+
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google

src/google/protobuf/generated_message_table_driven_lite.h

@@ -172,7 +172,7 @@ template <ProcessingType field_type>
 inline void ResetOneofField(const ParseTable& table, int field_number,
                             Arena* arena, MessageLite* msg, uint32* oneof_case,
                             int64 offset, const void* default_ptr) {
-  if (*oneof_case == field_number) {
+  if (static_cast<int64>(*oneof_case) == field_number) {
     // The oneof is already set to the right type, so there is no need to clear
     // it.
     return;

src/google/protobuf/generated_message_util.cc

@@ -52,10 +52,14 @@
 #include <google/protobuf/message_lite.h>
 #include <google/protobuf/metadata_lite.h>
 #include <google/protobuf/stubs/mutex.h>
-#include <google/protobuf/port_def.inc>
 #include <google/protobuf/repeated_field.h>
 #include <google/protobuf/wire_format_lite.h>
 
+// Must be included last
+#include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
+
 
 namespace google {
 namespace protobuf {
@@ -68,8 +72,9 @@ void DestroyString(const void* s) {
   static_cast<const std::string*>(s)->~basic_string();
 }
 
-PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT EmptyString
-    fixed_address_empty_string;  // NOLINT
+PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
+    PROTOBUF_ATTRIBUTE_INIT_PRIORITY EmptyString
+        fixed_address_empty_string;  // NOLINT
 
 
 PROTOBUF_CONSTINIT std::atomic<bool> init_protobuf_defaults_state{false};
@@ -90,6 +95,11 @@ void InitProtobufDefaultsSlow() {
   static bool is_inited = InitProtobufDefaultsImpl();
   (void)is_inited;
 }
+// Force the initialization of the empty string.
+// Normally, registration would do it, but we don't have any guarantee that
+// there is any object with reflection.
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static std::true_type init_empty_string =
+    (InitProtobufDefaultsSlow(), std::true_type{});
 
 size_t StringSpaceUsedExcludingSelfLong(const std::string& str) {
   const void* start = &str;
@@ -802,3 +812,5 @@ void InitSCCImpl(SCCInfoBase* scc) {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/implicit_weak_message.cc

@@ -63,3 +63,5 @@ const ImplicitWeakMessage* ImplicitWeakMessage::default_instance() {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/io/coded_stream.cc

@@ -312,7 +312,7 @@ bool CodedInputStream::ReadLittleEndian32Fallback(uint32* value) {
   uint8 bytes[sizeof(*value)];
 
   const uint8* ptr;
-  if (BufferSize() >= sizeof(*value)) {
+  if (BufferSize() >= static_cast<int64>(sizeof(*value))) {
     // Fast path:  Enough bytes in the buffer to read directly.
     ptr = buffer_;
     Advance(sizeof(*value));
@@ -329,7 +329,7 @@ bool CodedInputStream::ReadLittleEndian64Fallback(uint64* value) {
   uint8 bytes[sizeof(*value)];
 
   const uint8* ptr;
-  if (BufferSize() >= sizeof(*value)) {
+  if (BufferSize() >= static_cast<int64>(sizeof(*value))) {
     // Fast path:  Enough bytes in the buffer to read directly.
     ptr = buffer_;
     Advance(sizeof(*value));
@@ -351,7 +351,7 @@ template <size_t N>
 const uint8* DecodeVarint64KnownSize(const uint8* buffer, uint64* value) {
   GOOGLE_DCHECK_GT(N, 0);
   uint64 result = static_cast<uint64>(buffer[N - 1]) << (7 * (N - 1));
-  for (int i = 0, offset = 0; i < N - 1; i++, offset += 7) {
+  for (size_t i = 0, offset = 0; i < N - 1; i++, offset += 7) {
     result += static_cast<uint64>(buffer[i] - 0x80) << offset;
   }
   *value = result;
@@ -954,3 +954,5 @@ uint8* CodedOutputStream::WriteStringWithSizeToArray(const std::string& str,
 }  // namespace io
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/io/coded_stream_unittest.cc

@@ -1344,3 +1344,5 @@ TEST_F(CodedStreamTest, InputOver2G) {
 }  // namespace io
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/io/gzip_stream.cc

@@ -298,7 +298,7 @@ bool GzipOutputStream::Next(void** data, int* size) {
   return true;
 }
 void GzipOutputStream::BackUp(int count) {
-  GOOGLE_CHECK_GE(zcontext_.avail_in, count);
+  GOOGLE_CHECK_GE(zcontext_.avail_in, static_cast<uInt>(count));
   zcontext_.avail_in -= count;
 }
 int64_t GzipOutputStream::ByteCount() const {

src/google/protobuf/io/printer.cc

@@ -296,7 +296,7 @@ void Printer::FormatInternal(const std::vector<std::string>& args,
     }
     push_back(c);
   }
-  if (arg_index != args.size()) {
+  if (arg_index != static_cast<int>(args.size())) {
     GOOGLE_LOG(FATAL) << " Unused arguments. " << save;
   }
   if (!annotations.empty()) {
@@ -324,7 +324,7 @@ const char* Printer::WriteVariable(
     GOOGLE_CHECK(std::isdigit(start[1]));
     GOOGLE_CHECK_EQ(end - start, 2);
     int idx = start[1] - '1';
-    if (idx < 0 || idx >= args.size()) {
+    if (idx < 0 || static_cast<size_t>(idx) >= args.size()) {
       GOOGLE_LOG(FATAL) << "Annotation ${" << idx + 1 << "$ is out of bounds.";
     }
     if (idx > *arg_index) {
@@ -358,10 +358,10 @@ const char* Printer::WriteVariable(
       start_var, static_cast<std::string::size_type>(end_var - start_var)};
   std::string sub;
   if (std::isdigit(var_name[0])) {
-    GOOGLE_CHECK_EQ(var_name.size(), 1);  // No need for multi-digits
+    GOOGLE_CHECK_EQ(var_name.size(), 1U);  // No need for multi-digits
     int idx = var_name[0] - '1';   // Start counting at 1
     GOOGLE_CHECK_GE(idx, 0);
-    if (idx >= args.size()) {
+    if (static_cast<size_t>(idx) >= args.size()) {
       GOOGLE_LOG(FATAL) << "Argument $" << idx + 1 << "$ is out of bounds.";
     }
     if (idx > *arg_index) {

src/google/protobuf/io/tokenizer.cc

@@ -888,7 +888,8 @@ bool Tokenizer::ParseInteger(const std::string& text, uint64 max_value,
       // token, but Tokenizer still think it's integer.
       return false;
     }
-    if (digit > max_value || result > (max_value - digit) / base) {
+    if (static_cast<uint64>(digit) > max_value ||
+        result > (max_value - digit) / base) {
       // Overflow.
       return false;
     }
@@ -918,7 +919,8 @@ double Tokenizer::ParseFloat(const std::string& text) {
     ++end;
   }
 
-  GOOGLE_LOG_IF(DFATAL, end - start != text.size() || *start == '-')
+  GOOGLE_LOG_IF(DFATAL,
+         static_cast<size_t>(end - start) != text.size() || *start == '-')
       << " Tokenizer::ParseFloat() passed text that could not have been"
          " tokenized as a float: "
       << CEscape(text);
@@ -1114,8 +1116,8 @@ void Tokenizer::ParseStringAppend(const std::string& text,
 
 template <typename CharacterClass>
 static bool AllInClass(const std::string& s) {
-  for (int i = 0; i < s.size(); ++i) {
-    if (!CharacterClass::InClass(s[i])) return false;
+  for (const char character : s) {
+    if (!CharacterClass::InClass(character)) return false;
   }
   return true;
 }

src/google/protobuf/io/zero_copy_stream_impl_lite.cc

@@ -168,7 +168,7 @@ bool StringOutputStream::Next(void** data, int* size) {
 void StringOutputStream::BackUp(int count) {
   GOOGLE_CHECK_GE(count, 0);
   GOOGLE_CHECK(target_ != NULL);
-  GOOGLE_CHECK_LE(count, target_->size());
+  GOOGLE_CHECK_LE(static_cast<size_t>(count), target_->size());
   target_->resize(target_->size() - count);
 }
 

src/google/protobuf/map.h

@@ -838,7 +838,7 @@ class Map {
     // non-determinism to the map ordering.
     bool ShouldInsertAfterHead(void* node) {
 #ifdef NDEBUG
-      (void) node;
+      (void)node;
       return false;
 #else
       // Doing modulo with a prime mixes the bits more.

src/google/protobuf/map_field.cc

@@ -601,3 +601,5 @@ size_t DynamicMapField::SpaceUsedExcludingSelfNoLock() const {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/map_field.h

@@ -72,8 +72,8 @@ class MapIterator;
 // map key.
 class PROTOBUF_EXPORT MapKey {
  public:
-  MapKey() : type_(0) {}
-  MapKey(const MapKey& other) : type_(0) { CopyFrom(other); }
+  MapKey() : type_() {}
+  MapKey(const MapKey& other) : type_() { CopyFrom(other); }
 
   MapKey& operator=(const MapKey& other) {
     CopyFrom(other);
@@ -87,12 +87,12 @@ class PROTOBUF_EXPORT MapKey {
   }
 
   FieldDescriptor::CppType type() const {
-    if (type_ == 0) {
+    if (type_ == FieldDescriptor::CppType()) {
       GOOGLE_LOG(FATAL) << "Protocol Buffer map usage error:\n"
                  << "MapKey::type MapKey is not initialized. "
                  << "Call set methods to initialize MapKey.";
     }
-    return (FieldDescriptor::CppType)type_;
+    return type_;
   }
 
   void SetInt64Value(int64 value) {
@@ -261,7 +261,8 @@ class PROTOBUF_EXPORT MapKey {
   }
 
   // type_ is 0 or a valid FieldDescriptor::CppType.
-  int type_;
+  // Use "CppType()" to indicate zero.
+  FieldDescriptor::CppType type_;
 };
 
 }  // namespace protobuf
@@ -329,7 +330,7 @@ class PROTOBUF_EXPORT MapFieldBase {
   // It uses a linker initialized mutex, so it is not compatible with regular
   // runtime instances.
   // Except in MSVC, where we can't have a constinit mutex.
-  explicit PROTOBUF_MAYBE_CONSTEXPR MapFieldBase(ConstantInitialized)
+  explicit constexpr MapFieldBase(ConstantInitialized)
       : arena_(nullptr),
         repeated_field_(nullptr),
         mutex_(GOOGLE_PROTOBUF_LINKER_INITIALIZED),
@@ -678,7 +679,7 @@ class PROTOBUF_EXPORT DynamicMapField
 // the map value.
 class PROTOBUF_EXPORT MapValueConstRef {
  public:
-  MapValueConstRef() : data_(nullptr), type_(0) {}
+  MapValueConstRef() : data_(nullptr), type_() {}
 
   int64 GetInt64Value() const {
     TYPE_CHECK(FieldDescriptor::CPPTYPE_INT64,
@@ -735,15 +736,16 @@ class PROTOBUF_EXPORT MapValueConstRef {
   // own this value.
   void* data_;
   // type_ is 0 or a valid FieldDescriptor::CppType.
-  int type_;
+  // Use "CppType()" to indicate zero.
+  FieldDescriptor::CppType type_;
 
   FieldDescriptor::CppType type() const {
-    if (type_ == 0 || data_ == nullptr) {
+    if (type_ == FieldDescriptor::CppType() || data_ == nullptr) {
       GOOGLE_LOG(FATAL)
           << "Protocol Buffer map usage error:\n"
           << "MapValueConstRef::type MapValueConstRef is not initialized.";
     }
-    return static_cast<FieldDescriptor::CppType>(type_);
+    return type_;
   }
 
  private:

src/google/protobuf/map_field_test.cc

@@ -501,3 +501,5 @@ TEST(MapFieldTest, ConstInit) {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/map_test.cc

@@ -3770,3 +3770,5 @@ TEST(MoveTest, MoveAssignmentWorks) {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/message.cc

@@ -363,3 +363,5 @@ PROTOBUF_NOINLINE
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/message.h

@@ -1252,7 +1252,8 @@ const T* DynamicCastToGenerated(const Message* from) {
 #if PROTOBUF_RTTI
   return dynamic_cast<const T*>(from);
 #else
-  bool ok = T::default_instance().GetReflection() == from->GetReflection();
+  bool ok = from != nullptr &&
+            T::default_instance().GetReflection() == from->GetReflection();
   return ok ? down_cast<const T*>(from) : nullptr;
 #endif
 }

src/google/protobuf/message_lite.cc

@@ -389,7 +389,7 @@ bool MessageLite::SerializePartialToCodedStream(
   }
   int final_byte_count = output->ByteCount();
 
-  if (final_byte_count - original_byte_count != size) {
+  if (final_byte_count - original_byte_count != static_cast<int64>(size)) {
     ByteSizeConsistencyError(size, ByteSizeLong(),
                              final_byte_count - original_byte_count, *this);
   }
@@ -488,7 +488,7 @@ bool MessageLite::SerializePartialToArray(void* data, int size) const {
                << " exceeded maximum protobuf size of 2GB: " << byte_size;
     return false;
   }
-  if (size < byte_size) return false;
+  if (size < static_cast<int64>(byte_size)) return false;
   uint8* start = reinterpret_cast<uint8*>(data);
   SerializeToArrayImpl(*this, start, byte_size);
   return true;
@@ -581,3 +581,5 @@ void ShutdownProtobufLibrary() {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/message_lite.h

@@ -151,7 +151,6 @@ class ExplicitlyConstructed {
   } union_;
 };
 
-PROTOBUF_DISABLE_MSVC_UNION_WARNING
 // We need a publicly accessible `value` object to allow constexpr
 // support in C++11.
 // A constexpr accessor does not work portably.
@@ -163,7 +162,6 @@ union EmptyString {
   std::false_type dummy;
   std::string value;
 };
-PROTOBUF_ENABLE_MSVC_UNION_WARNING
 
 // Default empty string object. Don't use this directly. Instead, call
 // GetEmptyString() to get the reference.

src/google/protobuf/message_unittest.inc

@@ -235,6 +235,10 @@ TEST(MESSAGE_TEST_NAME, DynamicCastToGenerated) {
                 test_all_types_pointer_const));
   EXPECT_EQ(nullptr, DynamicCastToGenerated<const UNITTEST::TestRequired>(
                          test_all_types_pointer_const));
+
+  Message* test_all_types_pointer_nullptr = nullptr;
+  EXPECT_EQ(nullptr, DynamicCastToGenerated<UNITTEST::TestAllTypes>(
+                         test_all_types_pointer_nullptr));
 }
 
 #ifdef PROTOBUF_HAS_DEATH_TEST  // death tests do not work on Windows yet.

src/google/protobuf/parse_context.cc

@@ -591,3 +591,5 @@ const char* UnknownFieldParse(uint32 tag, std::string* unknown, const char* ptr,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/port.h

@@ -39,5 +39,9 @@
 
 #include <google/protobuf/stubs/port.h>
 
+// Protobuf intends to move into the pb:: namespace.
+namespace protobuf_future_namespace_placeholder {}
+namespace pb = ::protobuf_future_namespace_placeholder;
+
 
 #endif  // GOOGLE_PROTOBUF_PORT_H__

src/google/protobuf/port_def.inc

@@ -139,21 +139,21 @@
 #ifdef PROTOBUF_FINAL
 #error PROTOBUF_FINAL was previously defined
 #endif
-#ifdef PROTOBUF_DISABLE_MSVC_UNION_WARNING
-#error PROTOBUF_DISABLE_MSVC_UNION_WARNING was previously defined
-#endif
 #ifdef PROTOBUF_ENABLE_MSVC_UNION_WARNING
 #error PROTOBUF_ENABLE_MSVC_UNION_WARNING was previously defined
 #endif
 #ifdef PROTOBUF_CONSTINIT
 #error PROTOBUF_CONSTINIT was previously defined
 #endif
-#ifdef PROTOBUF_MAYBE_CONSTEXPR
-#error PROTOBUF_MAYBE_CONSTEXPR was previously defined
-#endif
 #ifdef PROTOBUF_ATTRIBUTE_NO_DESTROY
 #error PROTOBUF_ATTRIBUTE_NO_DESTROY was previously defined
 #endif
+#ifdef PROTOBUF_ATTRIBUTE_INIT_PRIORITY
+#error PROTOBUF_ATTRIBUTE_INIT_PRIORITY was previously defined
+#endif
+#ifdef PROTOBUF_PRAGMA_INIT_SEG
+#error PROTOBUF_PRAGMA_INIT_SEG was previously defined
+#endif
 
 
 #define PROTOBUF_NAMESPACE "google::protobuf"
@@ -464,10 +464,6 @@
 // name.
 #pragma push_macro("DEBUG")
 #undef DEBUG
-#pragma push_macro("TRUE")
-#undef TRUE
-#pragma push_macro("FALSE")
-#undef FALSE
 #endif // defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
 
 #if defined(__clang__)
@@ -560,28 +556,6 @@
 #define PROTOBUF_CONSTINIT
 #endif
 
-// Some constructors can't be constexpr under MSVC, but given that MSVC will not
-// do constant initialization of globals anyway we can omit `constexpr` from
-// them. These constructors are marked with PROTOBUF_MAYBE_CONSTEXPR
-#if defined(_MSC_VER)
-#define PROTOBUF_MAYBE_CONSTEXPR
-#else
-#define PROTOBUF_MAYBE_CONSTEXPR constexpr
-#endif
-
-#if _MSC_VER
-#define PROTOBUF_DISABLE_MSVC_UNION_WARNING \
-  __pragma(warning(push)) \
-  __pragma(warning(disable : 4582)) \
-  __pragma(warning(disable : 4583))
-
-#define PROTOBUF_ENABLE_MSVC_UNION_WARNING \
-  __pragma(warning(pop))
-#else
-#define PROTOBUF_DISABLE_MSVC_UNION_WARNING
-#define PROTOBUF_ENABLE_MSVC_UNION_WARNING
-#endif
-
 #if defined(__cpp_constinit)
 #define PROTOBUF_CONSTINIT constinit
 #elif defined(__has_cpp_attribute)
@@ -604,3 +578,34 @@
 #if !defined(PROTOBUF_ATTRIBUTE_NO_DESTROY)
 #define PROTOBUF_ATTRIBUTE_NO_DESTROY
 #endif
+
+#if defined(__GNUC__)
+// Protobuf extensions and reflection require registration of the protos linked
+// in the binary. Not until everything is registered does the runtime have a
+// complete view on all protos. When code is using reflection or extensions
+// in between registration calls this can lead to surprising behavior. By
+// having the registration run first we mitigate this scenario.
+// Highest priority is 101. We use 102 to allow code that really wants to
+// higher priority to still beat us.
+#define PROTOBUF_ATTRIBUTE_INIT_PRIORITY __attribute__((init_priority((102))))
+#else
+#define PROTOBUF_ATTRIBUTE_INIT_PRIORITY
+#endif
+
+#if _MSC_VER
+#define PROTOBUF_PRAGMA_INIT_SEG __pragma(init_seg(lib))
+#else
+#define PROTOBUF_PRAGMA_INIT_SEG
+#endif
+
+// Silence some MSVC warnings in all our code.
+#if _MSC_VER
+#pragma warning(push)
+// For non-trivial unions
+#pragma warning(disable : 4582)
+#pragma warning(disable : 4583)
+// For init_seg(lib)
+#pragma warning(disable : 4073)
+// To silence the fact that we will pop this push from another file
+#pragma warning(disable : 5031)
+#endif

src/google/protobuf/port_undef.inc

@@ -75,8 +75,9 @@
 #undef PROTOBUF_DISABLE_MSVC_UNION_WARNING
 #undef PROTOBUF_ENABLE_MSVC_UNION_WARNING
 #undef PROTOBUF_CONSTINIT
-#undef PROTOBUF_MAYBE_CONSTEXPR
 #undef PROTOBUF_ATTRIBUTE_NO_DESTROY
+#undef PROTOBUF_ATTRIBUTE_INIT_PRIORITY
+#undef PROTOBUF_PRAGMA_INIT_SEG
 
 // Restore macro that may have been #undef'd in port_def.inc.
 #ifdef _MSC_VER
@@ -105,8 +106,6 @@
 
 #if defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
 #pragma pop_macro("DEBUG")
-#pragma pop_macro("TRUE")
-#pragma pop_macro("FALSE")
 #endif // defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
 
 #if defined(__clang__)
@@ -114,3 +113,8 @@
 #elif defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif
+
+// Pop the warning(push) from port_def.inc
+#if _MSC_VER
+#pragma warning(pop)
+#endif

src/google/protobuf/reflection_ops.cc

@@ -436,3 +436,5 @@ void GenericSwap(Message* m1, Message* m2) {
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/repeated_field.cc

@@ -58,8 +58,10 @@ void** RepeatedPtrFieldBase::InternalExtend(int extend_amount) {
   Arena* arena = GetArena();
   new_size = std::max(internal::kRepeatedFieldLowerClampLimit,
                       std::max(total_size_ * 2, new_size));
-  GOOGLE_CHECK_LE(new_size, (std::numeric_limits<size_t>::max() - kRepHeaderSize) /
-                         sizeof(old_rep->elements[0]))
+  GOOGLE_CHECK_LE(
+      static_cast<int64>(new_size),
+      static_cast<int64>((std::numeric_limits<size_t>::max() - kRepHeaderSize) /
+                         sizeof(old_rep->elements[0])))
       << "Requested size is too large to fit into size_t.";
   size_t bytes = kRepHeaderSize + sizeof(old_rep->elements[0]) * new_size;
   if (arena == NULL) {
@@ -134,3 +136,5 @@ template class PROTOBUF_EXPORT_TEMPLATE_DEFINE RepeatedPtrField<std::string>;
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/repeated_field.h

@@ -1206,6 +1206,12 @@ RepeatedField<Element>::RepeatedField(Iter begin, const Iter& end)
 
 template <typename Element>
 RepeatedField<Element>::~RepeatedField() {
+#ifndef NDEBUG
+  // Try to trigger segfault / asan failure in non-opt builds. If arena_
+  // lifetime has ended before the destructor.
+  auto arena = GetArena();
+  if (arena) (void)arena->SpaceAllocated();
+#endif
   if (total_size_ > 0) {
     InternalDeallocate(rep(), total_size_);
   }

src/google/protobuf/repeated_field_unittest.cc

@@ -2090,3 +2090,5 @@ TEST_F(RepeatedFieldInsertionIteratorsTest, MoveProtos) {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/source_context.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class SourceContextDefaultTypeInternal {
  public:
@@ -75,7 +77,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fsource_5fcontext_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fsource_5fcontext_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fsource_5fcontext_2eproto(&descriptor_table_google_2fprotobuf_2fsource_5fcontext_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/struct.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fstruct_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<0> scc_info_ListValue_google_2fprotobuf_2fstruct_2eproto;
 PROTOBUF_NAMESPACE_OPEN
 class Struct_FieldsEntry_DoNotUseDefaultTypeInternal {
@@ -145,7 +147,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2fstruct_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2fstruct_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2fstruct_2eproto(&descriptor_table_google_2fprotobuf_2fstruct_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 const ::PROTOBUF_NAMESPACE_ID::EnumDescriptor* NullValue_descriptor() {
   ::PROTOBUF_NAMESPACE_ID::internal::AssignDescriptors(&descriptor_table_google_2fprotobuf_2fstruct_2eproto);

src/google/protobuf/stubs/common.cc

@@ -327,3 +327,5 @@ const char* FatalException::what() const throw() {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/stubs/int128.cc

@@ -190,3 +190,5 @@ std::ostream& operator<<(std::ostream& o, const uint128& b) {
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>  // NOLINT

src/google/protobuf/stubs/int128_unittest.cc

@@ -515,3 +515,5 @@ TEST(Int128, OStream) {
 }
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/stubs/mutex.h

@@ -90,12 +90,33 @@ class PROTOBUF_EXPORT CriticalSectionLock {
 
 #endif
 
+// In MSVC std::mutex does not have a constexpr constructor.
+// This wrapper makes the constructor constexpr.
+template <typename T>
+class CallOnceInitializedMutex {
+ public:
+  constexpr CallOnceInitializedMutex() : flag_{}, buf_{} {}
+  ~CallOnceInitializedMutex() { get().~T(); }
+
+  void lock() { get().lock(); }
+  void unlock() { get().unlock(); }
+
+ private:
+  T& get() {
+    std::call_once(flag_, [&] { ::new (static_cast<void*>(&buf_)) T(); });
+    return reinterpret_cast<T&>(buf_);
+  }
+
+  std::once_flag flag_;
+  alignas(T) char buf_[sizeof(T)];
+};
+
 // Mutex is a natural type to wrap. As both google and other organization have
 // specialized mutexes. gRPC also provides an injection mechanism for custom
 // mutexes.
 class GOOGLE_PROTOBUF_CAPABILITY("mutex") PROTOBUF_EXPORT WrappedMutex {
  public:
-  WrappedMutex() = default;
+  constexpr WrappedMutex() = default;
   void Lock() GOOGLE_PROTOBUF_ACQUIRE() { mu_.lock(); }
   void Unlock() GOOGLE_PROTOBUF_RELEASE() { mu_.unlock(); }
   // Crash if this Mutex is not held exclusively by this thread.
@@ -103,11 +124,13 @@ class GOOGLE_PROTOBUF_CAPABILITY("mutex") PROTOBUF_EXPORT WrappedMutex {
   void AssertHeld() const {}
 
  private:
-#ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP
+#if defined(GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP)
+  CallOnceInitializedMutex<CriticalSectionLock> mu_;
+#elif defined(_MSC_VER)
+  CallOnceInitializedMutex<std::mutex> mu_;
+#else
   std::mutex mu_;
-#else  // ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP
-  CriticalSectionLock mu_;
-#endif  // #ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP
+#endif
 };
 
 using Mutex = WrappedMutex;

src/google/protobuf/stubs/port.h

@@ -51,11 +51,11 @@
   #if !defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
     #define PROTOBUF_LITTLE_ENDIAN 1
   #endif
-  #if defined(_MSC_VER) && _MSC_VER >= 1300 && !defined(__INTEL_COMPILER)
-    // If MSVC has "/RTCc" set, it will complain about truncating casts at
-    // runtime.  This file contains some intentional truncating casts.
-    #pragma runtime_checks("c", off)
-  #endif
+#if defined(_MSC_VER) && _MSC_VER >= 1300 && !defined(__INTEL_COMPILER)
+// If MSVC has "/RTCc" set, it will complain about truncating casts at
+// runtime.  This file contains some intentional truncating casts.
+#pragma runtime_checks("c", off)
+#endif
 #else
   #include <sys/param.h>   // __BYTE_ORDER
   #if defined(__OpenBSD__)

src/google/protobuf/text_format.cc

@@ -54,7 +54,6 @@
 #include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/map_field.h>
 #include <google/protobuf/message.h>
-#include <google/protobuf/port_def.inc>
 #include <google/protobuf/repeated_field.h>
 #include <google/protobuf/unknown_field_set.h>
 #include <google/protobuf/wire_format_lite.h>
@@ -63,6 +62,9 @@
 #include <google/protobuf/stubs/map_util.h>
 #include <google/protobuf/stubs/stl_util.h>
 
+// Must be included last.
+#include <google/protobuf/port_def.inc>
+
 
 namespace google {
 namespace protobuf {
@@ -161,7 +163,7 @@ TextFormat::ParseLocation TextFormat::ParseInfoTree::GetLocation(
 
   const std::vector<TextFormat::ParseLocation>* locations =
       FindOrNull(locations_, field);
-  if (locations == nullptr || index >= locations->size()) {
+  if (locations == nullptr || index >= static_cast<int64>(locations->size())) {
     return TextFormat::ParseLocation();
   }
 
@@ -176,7 +178,7 @@ TextFormat::ParseInfoTree* TextFormat::ParseInfoTree::GetTreeForNested(
   }
 
   auto it = nested_.find(field);
-  if (it == nested_.end() || index >= it->second.size()) {
+  if (it == nested_.end() || index >= static_cast<int64>(it->second.size())) {
     return nullptr;
   }
 
@@ -1321,7 +1323,7 @@ class TextFormat::Printer::TextGenerator
       if (failed_) return;
     }
 
-    while (size > buffer_size_) {
+    while (static_cast<int64>(size) > buffer_size_) {
       // Data exceeds space in the buffer.  Copy what we can and request a
       // new buffer.
       if (buffer_size_ > 0) {
@@ -2393,7 +2395,8 @@ void TextFormat::Printer::PrintFieldValue(const Message& message,
       const std::string* value_to_print = &value;
       std::string truncated_value;
       if (truncate_string_field_longer_than_ > 0 &&
-          truncate_string_field_longer_than_ < value.size()) {
+          static_cast<size_t>(truncate_string_field_longer_than_) <
+              value.size()) {
         truncated_value = value.substr(0, truncate_string_field_longer_than_) +
                           "...<truncated>...";
         value_to_print = &truncated_value;
@@ -2576,3 +2579,5 @@ void TextFormat::Printer::PrintUnknownFields(
 
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/text_format_unittest.cc

@@ -2160,3 +2160,5 @@ TEST(TextFormatUnknownFieldTest, TestUnknownExtension) {
 }  // namespace text_format_unittest
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/timestamp.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 PROTOBUF_NAMESPACE_OPEN
 class TimestampDefaultTypeInternal {
  public:
@@ -76,7 +78,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2ftimestamp_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2ftimestamp_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2ftimestamp_2eproto(&descriptor_table_google_2fprotobuf_2ftimestamp_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 
 // ===================================================================

src/google/protobuf/type.pb.cc

@@ -14,6 +14,8 @@
 #include <google/protobuf/wire_format.h>
 // @@protoc_insertion_point(includes)
 #include <google/protobuf/port_def.inc>
+
+PROTOBUF_PRAGMA_INIT_SEG
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2fany_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<0> scc_info_Any_google_2fprotobuf_2fany_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2ftype_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_EnumValue_google_2fprotobuf_2ftype_2eproto;
 extern PROTOBUF_INTERNAL_EXPORT_google_2fprotobuf_2ftype_2eproto ::PROTOBUF_NAMESPACE_ID::internal::SCCInfo<1> scc_info_Field_google_2fprotobuf_2ftype_2eproto;
@@ -250,7 +252,7 @@ const ::PROTOBUF_NAMESPACE_ID::internal::DescriptorTable descriptor_table_google
 };
 
 // Force running AddDescriptors() at dynamic initialization time.
-static bool dynamic_init_dummy_google_2fprotobuf_2ftype_2eproto = (static_cast<void>(::PROTOBUF_NAMESPACE_ID::internal::AddDescriptors(&descriptor_table_google_2fprotobuf_2ftype_2eproto)), true);
+PROTOBUF_ATTRIBUTE_INIT_PRIORITY static ::PROTOBUF_NAMESPACE_ID::internal::AddDescriptorsRunner dynamic_init_dummy_google_2fprotobuf_2ftype_2eproto(&descriptor_table_google_2fprotobuf_2ftype_2eproto);
 PROTOBUF_NAMESPACE_OPEN
 const ::PROTOBUF_NAMESPACE_ID::EnumDescriptor* Field_Kind_descriptor() {
   ::PROTOBUF_NAMESPACE_ID::internal::AssignDescriptors(&descriptor_table_google_2fprotobuf_2ftype_2eproto);

src/google/protobuf/unknown_field_set.cc

@@ -183,7 +183,7 @@ void UnknownFieldSet::DeleteSubrange(int start, int num) {
     (fields_)[i + start].Delete();
   }
   // Slide down the remaining fields.
-  for (int i = start + num; i < fields_.size(); ++i) {
+  for (size_t i = start + num; i < fields_.size(); ++i) {
     (fields_)[i - num] = (fields_)[i];
   }
   // Pop off the # of deleted fields.
@@ -193,8 +193,8 @@ void UnknownFieldSet::DeleteSubrange(int start, int num) {
 }
 
 void UnknownFieldSet::DeleteByNumber(int number) {
-  int left = 0;  // The number of fields left after deletion.
-  for (int i = 0; i < fields_.size(); ++i) {
+  size_t left = 0;  // The number of fields left after deletion.
+  for (size_t i = 0; i < fields_.size(); ++i) {
     UnknownField* field = &(fields_)[i];
     if (field->number() == number) {
       field->Delete();
@@ -324,3 +324,5 @@ const char* UnknownFieldParse(uint64 tag, UnknownFieldSet* unknown,
 }  // namespace internal
 }  // namespace protobuf
 }  // namespace google
+
+#include <google/protobuf/port_undef.inc>

src/google/protobuf/util/delimited_message_util.cc

@@ -74,12 +74,18 @@ bool ParseDelimitedFromCodedStream(MessageLite* message,
     return false;
   }
 
+  // Get the position after any size bytes have been read (and only the message
+  // itself remains).
+  int position_after_size = input->CurrentPosition();
+
   // Tell the stream not to read beyond that size.
   io::CodedInputStream::Limit limit = input->PushLimit(size);
 
   // Parse the message.
   if (!message->MergeFromCodedStream(input)) return false;
   if (!input->ConsumedEntireMessage()) return false;
+  if (input->CurrentPosition() - position_after_size != static_cast<int>(size))
+    return false;
 
   // Release the limit.
   input->PopLimit(limit);

src/google/protobuf/util/delimited_message_util_test.cc

@@ -82,6 +82,35 @@ TEST(DelimitedMessageUtilTest, DelimitedMessages) {
   }
 }
 
+TEST(DelimitedMessageUtilTest, FailsAtEndOfStream) {
+  std::stringstream full_stream;
+  std::stringstream partial_stream;
+
+  {
+    protobuf_unittest::ForeignMessage message;
+    message.set_c(42);
+    message.set_d(24);
+    EXPECT_TRUE(SerializeDelimitedToOstream(message, &full_stream));
+
+    std::string full_output = full_stream.str();
+    ASSERT_GT(full_output.size(), size_t{2});
+    ASSERT_EQ(full_output[0], 4);
+
+    partial_stream << full_output[0] << full_output[1] << full_output[2];
+  }
+
+  {
+    bool clean_eof;
+    io::IstreamInputStream zstream(&partial_stream);
+
+    protobuf_unittest::ForeignMessage message;
+    clean_eof = true;
+    EXPECT_FALSE(ParseDelimitedFromZeroCopyStream(&message,
+        &zstream, &clean_eof));
+    EXPECT_FALSE(clean_eof);
+  }
+}
+
 }  // namespace util
 }  // namespace protobuf
 }  // namespace google

src/google/protobuf/util/message_differencer.cc

@@ -141,7 +141,7 @@ class MessageDifferencer::MultipleFieldsMapKeyComparator
       int path_index) const {
     const FieldDescriptor* field = key_field_path[path_index];
     std::vector<SpecificField> current_parent_fields(parent_fields);
-    if (path_index == key_field_path.size() - 1) {
+    if (path_index == static_cast<int64>(key_field_path.size() - 1)) {
       if (field->is_repeated()) {
         if (!message_differencer_->CompareRepeatedField(
                 message1, message2, field, &current_parent_fields)) {
@@ -187,7 +187,7 @@ class MessageDifferencer::MultipleFieldsMapKeyComparator
 void MatchIndicesPostProcessorForSmartList(
     std::vector<int>* match_list1, std::vector<int>* match_list2) {
   int last_matched_index = -1;
-  for (int i = 0; i < match_list1->size(); ++i) {
+  for (size_t i = 0; i < match_list1->size(); ++i) {
     if (match_list1->at(i) < 0) {
       continue;
     }
@@ -395,7 +395,7 @@ void MessageDifferencer::TreatAsMapWithMultipleFieldPathsAsKey(
   GOOGLE_CHECK_EQ(FieldDescriptor::CPPTYPE_MESSAGE, field->cpp_type())
       << "Field has to be message type.  Field name is: " << field->full_name();
   for (const auto& key_field_path : key_field_paths) {
-    for (int j = 0; j < key_field_path.size(); ++j) {
+    for (size_t j = 0; j < key_field_path.size(); ++j) {
       const FieldDescriptor* parent_field =
           j == 0 ? field : key_field_path[j - 1];
       const FieldDescriptor* child_field = key_field_path[j];
@@ -669,8 +669,8 @@ bool MessageDifferencer::CompareRequestedFieldsUsingSettings(
 FieldDescriptorArray MessageDifferencer::CombineFields(
     const FieldDescriptorArray& fields1, Scope fields1_scope,
     const FieldDescriptorArray& fields2, Scope fields2_scope) {
-  int index1 = 0;
-  int index2 = 0;
+  size_t index1 = 0;
+  size_t index2 = 0;
 
   tmp_message_fields_.clear();
 
@@ -1417,8 +1417,8 @@ bool MessageDifferencer::CompareUnknownFields(
 
   // Now that we have two sorted lists, we can detect fields which appear only
   // in one list or the other by traversing them simultaneously.
-  int index1 = 0;
-  int index2 = 0;
+  size_t index1 = 0;
+  size_t index2 = 0;
   while (index1 < fields1.size() || index2 < fields2.size()) {
     enum {
       ADDITION,
@@ -1523,12 +1523,14 @@ bool MessageDifferencer::CompareUnknownFields(
 
     if (IsUnknownFieldIgnored(message1, message2, specific_field,
                               *parent_field)) {
-      if (reporter_ != NULL) {
+      if (report_ignores_ && reporter_ != NULL) {
         parent_field->push_back(specific_field);
         reporter_->ReportUnknownFieldIgnored(message1, message2, *parent_field);
         parent_field->pop_back();
       }
-      return true;
+      if (change_type != ADDITION) ++index1;
+      if (change_type != DELETION) ++index2;
+      continue;
     }
 
     if (change_type == ADDITION || change_type == DELETION ||
@@ -1881,7 +1883,7 @@ MessageDifferencer::StreamReporter::~StreamReporter() {
 
 void MessageDifferencer::StreamReporter::PrintPath(
     const std::vector<SpecificField>& field_path, bool left_side) {
-  for (int i = 0; i < field_path.size(); ++i) {
+  for (size_t i = 0; i < field_path.size(); ++i) {
     if (i > 0) {
       printer_->Print(".");
     }