8341451: Remove C2HandleAnonOMOwnerStub

Reviewed-by: fyang, chagedorn

src/hotspot/cpu/aarch64/c2_CodeStubs_aarch64.cpp

@@ -64,31 +64,4 @@ void C2EntryBarrierStub::emit(C2_MacroAssembler& masm) {
   __ emit_int32(0);   // nmethod guard value
 }
 
-int C2HandleAnonOMOwnerStub::max_size() const {
-  // Max size of stub has been determined by testing with 0, in which case
-  // C2CodeStubList::emit() will throw an assertion and report the actual size that
-  // is needed.
-  return 24;
-}
-
-void C2HandleAnonOMOwnerStub::emit(C2_MacroAssembler& masm) {
-  __ bind(entry());
-  Register mon = monitor();
-  Register t = tmp();
-  assert(t != noreg, "need tmp register");
-
-  // Fix owner to be the current thread.
-  __ str(rthread, Address(mon, ObjectMonitor::owner_offset()));
-
-  // Pop owner object from lock-stack.
-  __ ldrw(t, Address(rthread, JavaThread::lock_stack_top_offset()));
-  __ subw(t, t, oopSize);
-#ifdef ASSERT
-  __ str(zr, Address(rthread, t));
-#endif
-  __ strw(t, Address(rthread, JavaThread::lock_stack_top_offset()));
-
-  __ b(continuation());
-}
-
 #undef __

src/hotspot/cpu/riscv/c2_CodeStubs_riscv.cpp

@@ -71,32 +71,4 @@ void C2EntryBarrierStub::emit(C2_MacroAssembler& masm) {
   __ emit_int32(0);  // nmethod guard value
 }
 
-int C2HandleAnonOMOwnerStub::max_size() const {
-  // Max size of stub has been determined by testing with 0 without using RISC-V compressed
-  // instruction-set extension, in which case C2CodeStubList::emit() will throw an assertion
-  // and report the actual size that is needed.
-  return 20 DEBUG_ONLY(+8);
-}
-
-void C2HandleAnonOMOwnerStub::emit(C2_MacroAssembler& masm) {
-  __ bind(entry());
-  Register mon = monitor();
-  Register t = tmp();
-  assert(t != noreg, "need tmp register");
-
-  // Fix owner to be the current thread.
-  __ sd(xthread, Address(mon, ObjectMonitor::owner_offset()));
-
-  // Pop owner object from lock-stack.
-  __ lwu(t, Address(xthread, JavaThread::lock_stack_top_offset()));
-  __ subw(t, t, oopSize);
-#ifdef ASSERT
-  __ add(t0, xthread, t);
-  __ sd(zr, Address(t0, 0));
-#endif
-  __ sw(t, Address(xthread, JavaThread::lock_stack_top_offset()));
-
-  __ j(continuation());
-}
-
 #undef __

src/hotspot/share/opto/c2_CodeStubs.hpp

@@ -117,21 +117,6 @@ public:
   Label& slow_path_continuation() { return continuation(); }
 };
 
-#ifdef _LP64
-class C2HandleAnonOMOwnerStub : public C2CodeStub {
-private:
-  Register _monitor;
-  Register _tmp;
-public:
-  C2HandleAnonOMOwnerStub(Register monitor, Register tmp = noreg) : C2CodeStub(),
-    _monitor(monitor), _tmp(tmp) {}
-  Register monitor() { return _monitor; }
-  Register tmp() { return _tmp; }
-  int max_size() const;
-  void emit(C2_MacroAssembler& masm);
-};
-#endif
-
 //-----------------------------C2GeneralStub-----------------------------------
 // A generalized stub that can be used to implement an arbitrary stub in a
 // type-safe manner. An example: