Automated rollback of commit 9b4ceb4770.

PiperOrigin-RevId: 540399237

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

@@ -1137,12 +1137,18 @@ void FileGenerator::GenerateReflectionInitializationCode(io::Printer* p) {
         }
       )cc");
 
-  p->Emit({{"dummy", UniqueName("dynamic_init_dummy", file_, options_)}},
-          R"cc(
-            // Force running AddDescriptors() at dynamic initialization time.
-            PROTOBUF_ATTRIBUTE_INIT_PRIORITY2
-            static ::_pbi::AddDescriptorsRunner $dummy$(&$desc_table$);
-          )cc");
+  // For descriptor.proto we want to avoid doing any dynamic initialization,
+  // because in some situations that would otherwise pull in a lot of
+  // unnecessary code that can't be stripped by --gc-sections. Descriptor
+  // initialization will still be performed lazily when it's needed.
+  if (file_->name() != "net/proto2/proto/descriptor.proto") {
+    p->Emit({{"dummy", UniqueName("dynamic_init_dummy", file_, options_)}},
+            R"cc(
+              // Force running AddDescriptors() at dynamic initialization time.
+              PROTOBUF_ATTRIBUTE_INIT_PRIORITY2
+              static ::_pbi::AddDescriptorsRunner $dummy$(&$desc_table$);
+            )cc");
+  }
 
   // However, we must provide a way to force initialize the default instances
   // of FileDescriptorProto which will be used during registration of other

src/google/protobuf/descriptor.cc

@@ -1963,7 +1963,13 @@ DescriptorPool* DescriptorPool::internal_generated_pool() {
 }
 
 const DescriptorPool* DescriptorPool::generated_pool() {
-  return internal_generated_pool();
+  const DescriptorPool* pool = internal_generated_pool();
+  // Ensure that descriptor.proto gets registered in the generated pool. It is a
+  // special case because it is included in the full runtime. We have to avoid
+  // registering it pre-main, because we need to ensure that the linker
+  // --gc-sections step can strip out the full runtime if it is unused.
+  DescriptorProto::descriptor();
+  return pool;
 }