Internal change.

PiperOrigin-RevId: 580726494
protocolbuffers · Nov 9, 2023 · 5987c89 · 5987c89
1 parent 6105bb1
commit 5987c89
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Showing 13 changed files with 196 additions and 13 deletions.
diff --git a/src/google/protobuf/compiler/cpp/helpers.cc b/src/google/protobuf/compiler/cpp/helpers.cc
@@ -1024,6 +1024,13 @@ bool IsPresentMessage(const Descriptor* descriptor, const Options& options) {
   return true;
 }
 
+const FieldDescriptor* FindHottestField(
+    const std::vector<const FieldDescriptor*>& fields, const Options& options) {
+  (void)fields;
+  (void)options;
+  return nullptr;
+}
+
 static bool HasRepeatedFields(const Descriptor* descriptor) {
   for (int i = 0; i < descriptor->field_count(); ++i) {
     if (descriptor->field(i)->label() == FieldDescriptor::LABEL_REPEATED) {

diff --git a/src/google/protobuf/compiler/cpp/helpers.h b/src/google/protobuf/compiler/cpp/helpers.h
@@ -15,6 +15,7 @@
 #include <iterator>
 #include <string>
 #include <tuple>
+#include <vector>
 
 #include "absl/container/flat_hash_map.h"
 #include "absl/log/absl_check.h"
@@ -429,6 +430,10 @@ bool ShouldForceAllocationOnConstruction(const Descriptor* desc,
 // Returns true if the message is present based on PDProto profile.
 bool IsPresentMessage(const Descriptor* descriptor, const Options& options);
 
+// Returns the most likely present field. Returns nullptr if not profile driven.
+const FieldDescriptor* FindHottestField(
+    const std::vector<const FieldDescriptor*>& fields, const Options& options);
+
 // Does the file contain any definitions that need extension_set.h?
 bool HasExtensionsOrExtendableMessage(const FileDescriptor* file);
 

diff --git a/src/google/protobuf/compiler/cpp/parse_function_generator.cc b/src/google/protobuf/compiler/cpp/parse_function_generator.cc
@@ -401,9 +401,29 @@ void ParseFunctionGenerator::GenerateTailCallTable(io::Printer* printer) {
       }
       format(
           "&$1$._instance,\n"
-          "$2$,  // fallback\n"
-          "",
+          "$2$,  // fallback\n",
           DefaultInstanceName(descriptor_, options_), fallback);
+      std::vector<const FieldDescriptor*> subtable_fields;
+      for (const auto& aux : tc_table_info_->aux_entries) {
+        if (aux.type == internal::TailCallTableInfo::kSubTable) {
+          subtable_fields.push_back(aux.field);
+        }
+      }
+      const auto* hottest = FindHottestField(subtable_fields, options_);
+      // We'll prefetch `to_prefetch->to_prefetch` unconditionally to avoid
+      // branches. Set the pointer to itself to avoid nullptr.
+      printer->Emit(
+          {{"hottest_type_name",
+            QualifiedClassName(
+                hottest == nullptr ? descriptor_ : hottest->message_type(),
+                options_)}},
+          // clang-format off
+          R"cc(
+#ifdef PROTOBUF_PREFETCH_PARSE_TABLE
+::_pbi::TcParser::GetTable<$hottest_type_name$>(),  // to_prefetch
+#endif  // PROTOBUF_PREFETCH_PARSE_TABLE
+          )cc");
+      // clang-format on
     }
     format("}, {{\n");
     {

diff --git a/src/google/protobuf/compiler/java/java_features.pb.cc b/src/google/protobuf/compiler/java/java_features.pb.cc
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
diff --git a/src/google/protobuf/cpp_features.pb.cc b/src/google/protobuf/cpp_features.pb.cc