8319947: Recursive lightweight locking: s390x implementation

Reviewed-by: aboldtch, lucy

Author: offamitkumar

src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp

@@ -67,9 +67,6 @@ void C1_MacroAssembler::lock_object(Register Rmark, Register Roop, Register Rbox
 
   verify_oop(Roop, FILE_AND_LINE);
 
-  // Load object header.
-  z_lg(Rmark, Address(Roop, hdr_offset));
-
   // Save object being locked into the BasicObjectLock...
   z_stg(Roop, Address(Rbox, BasicObjectLock::obj_offset()));
 
@@ -85,6 +82,10 @@ void C1_MacroAssembler::lock_object(Register Rmark, Register Roop, Register Rbox
     lightweight_lock(Roop, Rmark, tmp, slow_case);
   } else if (LockingMode == LM_LEGACY) {
     NearLabel done;
+
+    // Load object header.
+    z_lg(Rmark, Address(Roop, hdr_offset));
+
     // and mark it as unlocked.
     z_oill(Rmark, markWord::unlocked_value);
     // Save unlocked object header into the displaced header location on the stack.
@@ -141,12 +142,7 @@ void C1_MacroAssembler::unlock_object(Register Rmark, Register Roop, Register Rb
   verify_oop(Roop, FILE_AND_LINE);
 
   if (LockingMode == LM_LIGHTWEIGHT) {
-    const Register tmp = Z_R1_scratch;
-    z_lg(Rmark, Address(Roop, hdr_offset));
-    z_lgr(tmp, Rmark);
-    z_nill(tmp, markWord::monitor_value);
-    branch_optimized(Assembler::bcondNotZero, slow_case);
-    lightweight_unlock(Roop, Rmark, tmp, slow_case);
+    lightweight_unlock(Roop, Rmark, Z_R1_scratch, slow_case);
   } else if (LockingMode == LM_LEGACY) {
     // Test if object header is pointing to the displaced header, and if so, restore
     // the displaced header in the object. If the object header is not pointing to

src/hotspot/cpu/s390/c2_MacroAssembler_s390.cpp

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2017, 2022 SAP SE. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2024 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,6 +33,15 @@
 #define BLOCK_COMMENT(str) block_comment(str)
 #define BIND(label)        bind(label); BLOCK_COMMENT(#label ":")
 
+void C2_MacroAssembler::fast_lock_lightweight(Register obj, Register box, Register temp1, Register temp2) {
+  compiler_fast_lock_lightweight_object(obj, temp1, temp2);
+}
+
+
+void C2_MacroAssembler::fast_unlock_lightweight(Register obj, Register box, Register temp1, Register temp2) {
+  compiler_fast_unlock_lightweight_object(obj, temp1, temp2);
+}
+
 //------------------------------------------------------
 //   Special String Intrinsics. Implementation
 //------------------------------------------------------

src/hotspot/cpu/s390/c2_MacroAssembler_s390.hpp

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2017, 2022 SAP SE. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2024 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,6 +29,10 @@
 // C2_MacroAssembler contains high-level macros for C2
 
  public:
+  // Code used by cmpFastLockLightweight and cmpFastUnlockLightweight mach instructions in s390.ad file.
+  void fast_lock_lightweight(Register obj, Register box, Register temp1, Register temp2);
+  void fast_unlock_lightweight(Register obj, Register box, Register temp1, Register temp2);
+
   //-------------------------------------------
   // Special String Intrinsics Implementation.
   //-------------------------------------------

src/hotspot/cpu/s390/interp_masm_s390.cpp

@@ -1005,19 +1005,19 @@ void InterpreterMacroAssembler::lock_object(Register monitor, Register object) {
 
   // markWord header = obj->mark().set_unlocked();
 
-  // Load markWord from object into header.
-  z_lg(header, hdr_offset, object);
-
   if (DiagnoseSyncOnValueBasedClasses != 0) {
     load_klass(tmp, object);
     testbit(Address(tmp, Klass::access_flags_offset()), exact_log2(JVM_ACC_IS_VALUE_BASED_CLASS));
     z_btrue(slow_case);
   }
 
   if (LockingMode == LM_LIGHTWEIGHT) {
-    lightweight_lock(object, /* mark word */ header, tmp, slow_case);
+    lightweight_lock(object, header, tmp, slow_case);
   } else if (LockingMode == LM_LEGACY) {
 
+    // Load markWord from object into header.
+    z_lg(header, hdr_offset, object);
+
     // Set header to be (markWord of object | UNLOCK_VALUE).
     // This will not change anything if it was unlocked before.
     z_oill(header, markWord::unlocked_value);
@@ -1153,26 +1153,8 @@ void InterpreterMacroAssembler::unlock_object(Register monitor, Register object)
 
   // If we still have a lightweight lock, unlock the object and be done.
   if (LockingMode == LM_LIGHTWEIGHT) {
-    // Check for non-symmetric locking. This is allowed by the spec and the interpreter
-    // must handle it.
-
-    Register tmp = current_header;
-
-    // First check for lock-stack underflow.
-    z_lgf(tmp, Address(Z_thread, JavaThread::lock_stack_top_offset()));
-    compareU32_and_branch(tmp, (unsigned)LockStack::start_offset(), Assembler::bcondNotHigh, slow_case);
-
-    // Then check if the top of the lock-stack matches the unlocked object.
-    z_aghi(tmp, -oopSize);
-    z_lg(tmp, Address(Z_thread, tmp));
-    compare64_and_branch(tmp, object, Assembler::bcondNotEqual, slow_case);
-
-    z_lg(header, Address(object, hdr_offset));
-    z_lgr(tmp, header);
-    z_nill(tmp, markWord::monitor_value);
-    z_brne(slow_case);
 
-    lightweight_unlock(object, header, tmp, slow_case);
+    lightweight_unlock(object, header, current_header, slow_case);
 
     z_bru(done);
   } else {