RFR: 8330851: C2: More efficient TypeFunc creation

[Amit Kumar]

On Mon, 18 Nov 2024 20:16:02 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> > Is there some arena-specific check that exists, which could be used here ?
> 
> `_type_arena != &_Compile_types` on current `Compile` should reliably detect when shared type dictionary is being populated.

I can't access `_type_arena` in the initialize method directly. So will this change be fine: 


diff --git a/src/hotspot/share/opto/compile.hpp b/src/hotspot/share/opto/compile.hpp
index 05e24bf3f6e..6dbed935218 100644
--- a/src/hotspot/share/opto/compile.hpp
+++ b/src/hotspot/share/opto/compile.hpp
@@ -964,6 +964,7 @@ class Compile : public Phase {
   Dict*             type_dict()                 { return _type_dict; }
   size_t            type_last_size()            { return _type_last_size; }
   int               num_alias_types()           { return _num_alias_types; }
+  Arena*            compile_type_arena()        { return &_Compile_types; }
 
   void          init_type_arena()                       { _type_arena = &_Compile_types; }
   void          set_type_arena(Arena* a)                { _type_arena = a; }
diff --git a/src/hotspot/share/opto/runtime.cpp b/src/hotspot/share/opto/runtime.cpp
index b91844d383f..95cab3fd117 100644
--- a/src/hotspot/share/opto/runtime.cpp
+++ b/src/hotspot/share/opto/runtime.cpp
@@ -2044,7 +2044,8 @@ NamedCounter* OptoRuntime::new_named_counter(JVMState* youngest_jvms, NamedCount
   return c;
 }
 
-void OptoRuntime::initialize_types() {
+void OptoRuntime::initialize_types(Compile* current) {
+  assert(current->type_arena() != current->compile_type_arena(), "should be shared arena");
   new_instance_Type_init();
   new_array_Type_init();
   multianewarray2_Type_init();
diff --git a/src/hotspot/share/opto/runtime.hpp b/src/hotspot/share/opto/runtime.hpp
index 14dc03fef25..b2c32366157 100644
--- a/src/hotspot/share/opto/runtime.hpp
+++ b/src/hotspot/share/opto/runtime.hpp
@@ -770,7 +770,7 @@ class OptoRuntime : public AllStatic {
  // dumps all the named counters
  static void          print_named_counters();
 
- static void          initialize_types();
+ static void          initialize_types(Compile* current);
 };
 
 #endif // SHARE_OPTO_RUNTIME_HPP
diff --git a/src/hotspot/share/opto/type.cpp b/src/hotspot/share/opto/type.cpp
index 40d688085b5..86949786284 100644
--- a/src/hotspot/share/opto/type.cpp
+++ b/src/hotspot/share/opto/type.cpp
@@ -713,7 +713,7 @@ void Type::Initialize_shared(Compile* current) {
   mreg2type[Op_VecZ] = TypeVect::VECTZ;
 
   LockNode::lock_type_init();
-  OptoRuntime::initialize_types();
+  OptoRuntime::initialize_types(current);
 
   // Restore working type arena.
   current->set_type_arena(save);

-------------

PR Comment: https://git.openjdk.org/jdk/pull/21782#issuecomment-2489319551