src/share/vm/opto/library_call.cpp

rev 10065 : 8147844: new method j.l.Runtime.onSpinWait() and the corresponding x86 hotspot instrinsic
Summary: adds c1 & c2 x86 intrinsics for j.l.Runtime.onSpinWait() that utilize the 'pause' instruction
Contributed-by: ikrylov, ygaevsky
Reviewed-by: iveresov, vlivanov, kvn

*** 276,285 ****
--- 276,286 ----
  
    typedef enum { LS_xadd, LS_xchg, LS_cmpxchg } LoadStoreKind;
    bool inline_unsafe_load_store(BasicType type,  LoadStoreKind kind);
    bool inline_unsafe_ordered_store(BasicType type);
    bool inline_unsafe_fence(vmIntrinsics::ID id);
+   bool inline_onspinwait();
    bool inline_fp_conversions(vmIntrinsics::ID id);
    bool inline_number_methods(vmIntrinsics::ID id);
    bool inline_reference_get();
    bool inline_Class_cast();
    bool inline_aescrypt_Block(vmIntrinsics::ID id);
*** 636,645 ****
--- 637,648 ----
  
    case vmIntrinsics::_loadFence:
    case vmIntrinsics::_storeFence:
    case vmIntrinsics::_fullFence:                return inline_unsafe_fence(intrinsic_id());
  
+   case vmIntrinsics::_onSpinWait:               return inline_onspinwait();
+ 
    case vmIntrinsics::_currentThread:            return inline_native_currentThread();
    case vmIntrinsics::_isInterrupted:            return inline_native_isInterrupted();
  
  #ifdef TRACE_HAVE_INTRINSICS
    case vmIntrinsics::_classID:                  return inline_native_classID();
*** 2885,2894 ****
--- 2888,2902 ----
        fatal_unexpected_iid(id);
        return false;
    }
  }
  
+ bool LibraryCallKit::inline_onspinwait() {
+   insert_mem_bar(Op_OnSpinWait);
+   return true;
+ }
+ 
  bool LibraryCallKit::klass_needs_init_guard(Node* kls) {
    if (!kls->is_Con()) {
      return true;
    }
    const TypeKlassPtr* klsptr = kls->bottom_type()->isa_klassptr();