Shrink code size of generated protocol buffer code via a few

changes.

(1) Use PROTOBUF_NOINLINE attributes to avoid inlining of
Clear(), ByteSizeLong() and IsInitialized() routines
within the same .pb.cc file

(2) If the tag number is less than 16 and the type is one of
a handful of common types, call a non-inlined templated
routine specialized for that tag number that handles both
the EnsureSpace call and the encoding of the tag and the
value into the array.

PiperOrigin-RevId: 529162319

src/google/protobuf/compiler/cpp/field_generators/primitive_field.cc

@@ -257,11 +257,25 @@ void SingularPrimitive::GenerateInlineAccessorDefinitions(
 
 void SingularPrimitive::GenerateSerializeWithCachedSizesToArray(
     io::Printer* p) const {
-  p->Emit(R"cc(
-    target = stream->EnsureSpace(target);
-    target = ::_pbi::WireFormatLite::Write$DeclaredType$ToArray(
-        $number$, this->_internal_$name$(), target);
-  )cc");
+  if ((descriptor_->number() < 16) &&
+      (descriptor_->type() == FieldDescriptor::TYPE_INT32 ||
+       descriptor_->type() == FieldDescriptor::TYPE_INT64 ||
+       descriptor_->type() == FieldDescriptor::TYPE_ENUM)) {
+    // Call special non-inlined routine with tag number hardcoded as a
+    // template parameter that handles the EnsureSpace and the writing
+    // of the tag+value to the array
+    p->Emit(R"cc(
+      target = ::$proto_ns$::internal::WireFormatLite::
+          Write$declared_type$ToArrayWithField<$number$>(
+              stream, this->_internal_$name$(), target);
+    )cc");
+  } else {
+    p->Emit(R"cc(
+      target = stream->EnsureSpace(target);
+      target = ::_pbi::WireFormatLite::Write$DeclaredType$ToArray(
+          $number$, this->_internal_$name$(), target);
+    )cc");
+  }
 }
 
 void SingularPrimitive::GenerateByteSize(io::Printer* p) const {

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

@@ -2852,7 +2852,7 @@ void MessageGenerator::GenerateClear(io::Printer* p) {
   const int kMaxUnconditionalPrimitiveBytesClear = 4;
 
   format(
-      "void $classname$::Clear() {\n"
+      "PROTOBUF_NOINLINE void $classname$::Clear() {\n"
       "// @@protoc_insertion_point(message_clear_start:$full_name$)\n");
   format.Indent();
 
@@ -3939,7 +3939,7 @@ void MessageGenerator::GenerateByteSize(io::Printer* p) {
   if (descriptor_->options().message_set_wire_format()) {
     // Special-case MessageSet.
     format(
-        "::size_t $classname$::ByteSizeLong() const {\n"
+        "PROTOBUF_NOINLINE ::size_t $classname$::ByteSizeLong() const {\n"
         "$annotate_bytesize$"
         "// @@protoc_insertion_point(message_set_byte_size_start:$full_name$)\n"
         "  ::size_t total_size = $extensions$.MessageSetByteSize();\n"
@@ -4182,7 +4182,7 @@ void MessageGenerator::GenerateByteSize(io::Printer* p) {
 void MessageGenerator::GenerateIsInitialized(io::Printer* p) {
   if (HasSimpleBaseClass(descriptor_, options_)) return;
   Formatter format(p);
-  format("bool $classname$::IsInitialized() const {\n");
+  format("PROTOBUF_NOINLINE bool $classname$::IsInitialized() const {\n");
   format.Indent();
 
   if (descriptor_->extension_range_count() > 0) {