src/hotspot/cpu/aarch64/c1_CodeStubs_aarch64.cpp

*** 251,10 ***
--- 251,35 ---
    }
    __ adr(lr, _continuation);
    __ far_jump(RuntimeAddress(Runtime1::entry_for(exit_id)));
  }
  
+ void LoadKlassStub::emit_code(LIR_Assembler* ce) {
+   __ bind(_entry);
+   Register res = _result->as_register();
+   ce->store_parameter(_obj->as_register(), 0);
+   if (res != r0) {
+     // Note: we cannot push/pop r0 around the call, because that
+     // would mess with the stack pointer sp, and we need that to
+     // remain intact for store_paramater/load_argument to work correctly.
+     // We swap r0 and res instead, which preserves current r0 in res.
+     // The preserved value is later saved and restored around the
+     // call in Runtime1::load_klass_id.
+     __ mov(rscratch1, r0);
+     __ mov(r0, res);
+     __ mov(res, rscratch1);
+   }
+   __ far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::load_klass_id)));
+   if (res != r0) {
+     // Swap back r0 and res. This brings the call return value
+     // from r0 into res, and the preserved value in res back into r0.
+     __ mov(rscratch1, r0);
+     __ mov(r0, res);
+     __ mov(res, rscratch1);
+   }
+   __ b(_continuation);
+ }
  
  // Implementation of patching:
  // - Copy the code at given offset to an inlined buffer (first the bytes, then the number of bytes)
  // - Replace original code with a call to the stub
  // At Runtime: