fix call vs branch issue

Author: offamitkumar

src/hotspot/cpu/s390/sharedRuntime_s390.cpp

@@ -2182,21 +2182,9 @@ nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,
   // So if we must call out we must push a new frame.
   //////////////////////////////////////////////////////////////////////
 
-  if (method->is_object_wait0()) {
-    // The last java pc will also be used as resume pc if this is the wrapper for wait0.
-    // For this purpose the precise location matters but not for oopmap lookup.
-    __ load_const(Z_R10, last_java_pc);
-  } else {
-    // Calc the current pc into Z_R10 and into wrapper_CRegsSet.
-    // Both values represent the same position.
-    __ get_PC(Z_R10);                // PC into register
-    wrapper_CRegsSet = __ offset();  // and into into variable.
-
-    // Z_R10 now has the pc loaded that we will use when we finally call to native.
-
-    // We use the same pc/oopMap repeatedly when we call out.
-    oop_maps->add_gc_map((int)(wrapper_CRegsSet-wrapper_CodeStart), map);
-  }
+  // The last java pc will also be used as resume pc if this is the wrapper for wait0.
+  // For this purpose the precise location matters but not for oopmap lookup.
+  __ load_const(Z_R10, last_java_pc);
 
   // Lock a synchronized method.
 
@@ -2374,24 +2362,24 @@ nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,
   // Transition from _thread_in_native_trans to _thread_in_Java.
   __ set_thread_state(_thread_in_Java);
 
+  // Check preemption for Object.wait()
   if (method->is_object_wait0()) {
+    __ stop("crash here also");
     Label not_preempted;
     __ z_ltg(Z_R1_scratch, Address(Z_thread, JavaThread::preempt_alternate_return_offset()));
     __ z_brz(not_preempted); // if 0, jump to not_preempted
     __ z_mvghi(Address(Z_thread, JavaThread::preempt_alternate_return_offset()), 0);
-    __ call(Z_R1_scratch);
+    __ z_br(Z_R1_scratch);
     __ bind(not_preempted);
 
-    __ bind(last_java_pc);
+  }
+  __ bind(last_java_pc);
 
-    // Calc the current pc into Z_R10 and into wrapper_CRegsSet.
-    // Both values represent the same position.
-    __ get_PC(Z_R10);
-    wrapper_CRegsSet = __ offset();  // and into into variable.
+  // Calc the current pc into wrapper_CRegsSet.
+  wrapper_CRegsSet = __ offset();  // and into into variable.
 
-    // We use the same pc/oopMap repeatedly when we call out.
-    oop_maps->add_gc_map((int)(wrapper_CRegsSet-wrapper_CodeStart), map);
-  }
+  // We use the same pc/oopMap repeatedly when we call out.
+  oop_maps->add_gc_map((int)(wrapper_CRegsSet-wrapper_CodeStart), map);
 
   //--------------------------------------------------------------------
   // Reguard any pages if necessary.
@@ -2495,6 +2483,7 @@ nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,
   // Clear "last Java frame" SP and PC.
   //--------------------------------------------------------------------
 
+  // TODO: FIX THIS, Last java frame won't be set if we're resuming after preemption
   __ reset_last_Java_frame();
 
   // Unpack oop result, e.g. JNIHandles::resolve result.