8307533: Use atomic bitset functions for metadata flags

Reviewed-by: ccheung, kbarrett

Author: coleenp

src/hotspot/share/oops/fieldInfo.inline.hpp

@@ -30,6 +30,7 @@
 #include "memory/metadataFactory.hpp"
 #include "oops/constantPool.hpp"
 #include "oops/symbol.hpp"
+#include "runtime/atomic.hpp"
 
 inline Symbol* FieldInfo::name(ConstantPool* cp) const {
   int index = _name_index;
@@ -151,23 +152,11 @@ inline FieldInfoReader& FieldInfoReader::set_position_and_next_index(int positio
 }
 
 inline void FieldStatus::atomic_set_bits(u1& flags, u1 mask) {
-  // Atomically update the flags with the bits given
-  u1 old_flags, new_flags, witness;
-  do {
-    old_flags = flags;
-    new_flags = old_flags | mask;
-    witness = Atomic::cmpxchg(&flags, old_flags, new_flags);
-  } while (witness != old_flags);
+  Atomic::fetch_then_or(&flags, mask);
 }
 
 inline void FieldStatus::atomic_clear_bits(u1& flags, u1 mask) {
-  // Atomically update the flags with the bits given
-  u1 old_flags, new_flags, witness;
-  do {
-    old_flags = flags;
-    new_flags = old_flags & ~mask;
-    witness = Atomic::cmpxchg(&flags, old_flags, new_flags);
-  } while (witness != old_flags);
+  Atomic::fetch_then_and(&flags, (u1)(~mask));
 }
 
 inline void FieldStatus::update_flag(FieldStatusBitPosition pos, bool z) {

src/hotspot/share/oops/instanceKlassFlags.cpp

@@ -26,32 +26,10 @@
 #include "classfile/classLoader.hpp"
 #include "classfile/classLoaderData.inline.hpp"
 #include "oops/instanceKlassFlags.hpp"
-#include "runtime/atomic.hpp"
 #include "runtime/safepoint.hpp"
 #include "utilities/macros.hpp"
 #include "utilities/ostream.hpp"
 
-// This can be removed for the atomic bitset functions, when available.
-void InstanceKlassFlags::atomic_set_bits(u1 bits) {
-  // Atomically update the status with the bits given
-  u1 old_status, new_status, f;
-  do {
-    old_status = _status;
-    new_status = old_status | bits;
-    f = Atomic::cmpxchg(&_status, old_status, new_status);
-  } while(f != old_status);
-}
-
-void InstanceKlassFlags::atomic_clear_bits(u1 bits) {
-  // Atomically update the status with the bits given
-  u1 old_status, new_status, f;
-  do {
-    old_status = _status;
-    new_status = old_status & ~bits;
-    f = Atomic::cmpxchg(&_status, old_status, new_status);
-  } while(f != old_status);
-}
-
 void InstanceKlassFlags::print_on(outputStream* st) const {
 #define IK_FLAGS_PRINT(name, ignore)          \
   if (name()) st->print(" ##name ");

src/hotspot/share/oops/instanceKlassFlags.hpp

@@ -25,6 +25,8 @@
 #ifndef SHARE_OOPS_INSTANCEKLASSFLAGS_HPP
 #define SHARE_OOPS_INSTANCEKLASSFLAGS_HPP
 
+#include "runtime/atomic.hpp"
+
 class ClassLoaderData;
 
 // The InstanceKlassFlags class contains the parse-time and writeable flags associated with
@@ -121,8 +123,8 @@ class InstanceKlassFlags {
   IK_STATUS_DO(IK_STATUS_GET_SET)
 #undef IK_STATUS_GET_SET
 
-  void atomic_set_bits(u1 bits);
-  void atomic_clear_bits(u1 bits);
+  void atomic_set_bits(u1 bits)   { Atomic::fetch_then_or(&_status, bits); }
+  void atomic_clear_bits(u1 bits) { Atomic::fetch_then_and(&_status, (u1)(~bits)); }
   void print_on(outputStream* st) const;
 };
 

src/hotspot/share/oops/methodFlags.cpp

@@ -24,30 +24,8 @@
 
 #include "precompiled.hpp"
 #include "oops/methodFlags.hpp"
-#include "runtime/atomic.hpp"
 #include "utilities/ostream.hpp"
 
-// This can be removed for the atomic bitset functions, when available.
-void MethodFlags::atomic_set_bits(u4 bits) {
-  // Atomically update the status with the bits given
-  u4 old_status, new_status, f;
-  do {
-    old_status = _status;
-    new_status = old_status | bits;
-    f = Atomic::cmpxchg(&_status, old_status, new_status);
-  } while(f != old_status);
-}
-
-void MethodFlags::atomic_clear_bits(u4 bits) {
-  // Atomically update the status with the bits given
-  u4 old_status, new_status, f;
-  do {
-    old_status = _status;
-    new_status = old_status & ~bits;
-    f = Atomic::cmpxchg(&_status, old_status, new_status);
-  } while(f != old_status);
-}
-
 void MethodFlags::print_on(outputStream* st) const {
 #define M_PRINT(name, ignore)          \
   if (name()) st->print(" " #name " ");

src/hotspot/share/oops/methodFlags.hpp

@@ -25,6 +25,7 @@
 #ifndef SHARE_OOPS_METHODFLAGS_HPP
 #define SHARE_OOPS_METHODFLAGS_HPP
 
+#include "runtime/atomic.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/macros.hpp"
 
@@ -86,8 +87,8 @@ class MethodFlags {
 #undef M_STATUS_GET_SET
 
   int as_int() const { return _status; }
-  void atomic_set_bits(u4 bits);
-  void atomic_clear_bits(u4 bits);
+  void atomic_set_bits(u4 bits)   { Atomic::fetch_then_or(&_status, bits); }
+  void atomic_clear_bits(u4 bits) { Atomic::fetch_then_and(&_status, ~bits); }
   void print_on(outputStream* st) const;
 };