diff --git a/src/hotspot/cpu/ppc/abstractInterpreter_ppc.cpp b/src/hotspot/cpu/ppc/abstractInterpreter_ppc.cpp
index 65d110edb52..3280330f1d0 100644
--- a/src/hotspot/cpu/ppc/abstractInterpreter_ppc.cpp
+++ b/src/hotspot/cpu/ppc/abstractInterpreter_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2015 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -94,9 +94,9 @@ int AbstractInterpreter::size_activation(int max_stack,
 //
 // Parameters:
 //
-// interpreter_frame != NULL:
+// interpreter_frame != nullptr:
 //   set up the method, locals, and monitors.
-//   The frame interpreter_frame, if not NULL, is guaranteed to be the
+//   The frame interpreter_frame, if not null, is guaranteed to be the
 //   right size, as determined by a previous call to this method.
 //   It is also guaranteed to be walkable even though it is in a skeletal state
 //
diff --git a/src/hotspot/cpu/ppc/assembler_ppc.hpp b/src/hotspot/cpu/ppc/assembler_ppc.hpp
index 7ea6d8e5876..094d894d2da 100644
--- a/src/hotspot/cpu/ppc/assembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/assembler_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2022 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -95,7 +95,7 @@ class AddressLiteral {
 
  protected:
   // creation
-  AddressLiteral() : _address(NULL), _rspec() {}
+  AddressLiteral() : _address(nullptr), _rspec() {}
 
  public:
   AddressLiteral(address addr, RelocationHolder const& rspec)
@@ -1349,14 +1349,14 @@ class Assembler : public AbstractAssembler {
   inline void emit_data(int, relocInfo::relocType rtype);
 
   // Emit an address.
-  inline address emit_addr(const address addr = NULL);
+  inline address emit_addr(const address addr = nullptr);
 
 #if !defined(ABI_ELFv2)
   // Emit a function descriptor with the specified entry point, TOC,
-  // and ENV. If the entry point is NULL, the descriptor will point
+  // and ENV. If the entry point is null, the descriptor will point
   // just past the descriptor.
   // Use values from friend functions as defaults.
-  inline address emit_fd(address entry = NULL,
+  inline address emit_fd(address entry = nullptr,
                          address toc = (address) FunctionDescriptor::friend_toc,
                          address env = (address) FunctionDescriptor::friend_env);
 #endif
diff --git a/src/hotspot/cpu/ppc/assembler_ppc.inline.hpp b/src/hotspot/cpu/ppc/assembler_ppc.inline.hpp
index fc5df27148a..82a380b6e31 100644
--- a/src/hotspot/cpu/ppc/assembler_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/assembler_ppc.inline.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2020 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -58,7 +58,7 @@ inline address Assembler::emit_addr(const address addr) {
 
 #if !defined(ABI_ELFv2)
 // Emit a function descriptor with the specified entry point, TOC, and
-// ENV. If the entry point is NULL, the descriptor will point just
+// ENV. If the entry point is null, the descriptor will point just
 // past the descriptor.
 inline address Assembler::emit_fd(address entry, address toc, address env) {
   FunctionDescriptor* fd = (FunctionDescriptor*)pc();
@@ -69,7 +69,7 @@ inline address Assembler::emit_fd(address entry, address toc, address env) {
   (void)emit_addr();
   (void)emit_addr();
 
-  fd->set_entry(entry == NULL ? pc() : entry);
+  fd->set_entry(entry == nullptr ? pc() : entry);
   fd->set_toc(toc);
   fd->set_env(env);
 
diff --git a/src/hotspot/cpu/ppc/c1_CodeStubs_ppc.cpp b/src/hotspot/cpu/ppc/c1_CodeStubs_ppc.cpp
index 36d47e5a1d0..1a00c9ad268 100644
--- a/src/hotspot/cpu/ppc/c1_CodeStubs_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c1_CodeStubs_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -42,7 +42,7 @@ void C1SafepointPollStub::emit_code(LIR_Assembler* ce) {
   if (UseSIGTRAP) {
     DEBUG_ONLY( __ should_not_reach_here("C1SafepointPollStub::emit_code"); )
   } else {
-    assert(SharedRuntime::polling_page_return_handler_blob() != NULL,
+    assert(SharedRuntime::polling_page_return_handler_blob() != nullptr,
            "polling page return stub not created yet");
     address stub = SharedRuntime::polling_page_return_handler_blob()->entry_point();
 
@@ -336,12 +336,12 @@ void PatchingStub::emit_code(LIR_Assembler* ce) {
 
   if (_id == load_klass_id) {
     // Produce a copy of the load klass instruction for use by the being initialized case.
-    AddressLiteral addrlit((address)NULL, metadata_Relocation::spec(_index));
+    AddressLiteral addrlit((address)nullptr, metadata_Relocation::spec(_index));
     __ load_const(_obj, addrlit, R0);
     DEBUG_ONLY( compare_with_patch_site(__ code_section()->start() + being_initialized_entry, _pc_start, _bytes_to_copy); )
   } else if (_id == load_mirror_id || _id == load_appendix_id) {
     // Produce a copy of the load mirror instruction for use by the being initialized case.
-    AddressLiteral addrlit((address)NULL, oop_Relocation::spec(_index));
+    AddressLiteral addrlit((address)nullptr, oop_Relocation::spec(_index));
     __ load_const(_obj, addrlit, R0);
     DEBUG_ONLY( compare_with_patch_site(__ code_section()->start() + being_initialized_entry, _pc_start, _bytes_to_copy); )
   } else {
@@ -400,7 +400,7 @@ void PatchingStub::emit_code(LIR_Assembler* ce) {
 
   address entry = __ pc();
   NativeGeneralJump::insert_unconditional((address)_pc_start, entry);
-  address target = NULL;
+  address target = nullptr;
   relocInfo::relocType reloc_type = relocInfo::none;
   switch (_id) {
     case access_field_id:  target = Runtime1::entry_for(Runtime1::access_field_patching_id); break;
diff --git a/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp b/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp
index 8e9f7aba2d1..dd78a3d492f 100644
--- a/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2022 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -150,7 +150,7 @@ void LIR_Assembler::osr_entry() {
         __ ld(R0, slot_offset + 1*BytesPerWord, OSR_buf);
         __ cmpdi(CCR0, R0, 0);
         __ bne(CCR0, L);
-        __ stop("locked object is NULL");
+        __ stop("locked object is null");
         __ bind(L);
       }
 #endif // ASSERT
@@ -171,7 +171,7 @@ int LIR_Assembler::emit_exception_handler() {
   // Generate code for the exception handler.
   address handler_base = __ start_a_stub(exception_handler_size());
 
-  if (handler_base == NULL) {
+  if (handler_base == nullptr) {
     // Not enough space left for the handler.
     bailout("exception handler overflow");
     return -1;
@@ -211,7 +211,7 @@ int LIR_Assembler::emit_unwind_handler() {
   if (preserve_exception) { __ mr(Rexception_save, Rexception); }
 
   // Perform needed unlocking
-  MonitorExitStub* stub = NULL;
+  MonitorExitStub* stub = nullptr;
   if (method()->is_synchronized()) {
     monitor_address(0, FrameMap::R4_opr);
     stub = new MonitorExitStub(FrameMap::R4_opr, true, 0);
@@ -232,7 +232,7 @@ int LIR_Assembler::emit_unwind_handler() {
   __ bctr();
 
   // Emit the slow path assembly.
-  if (stub != NULL) {
+  if (stub != nullptr) {
     stub->emit_code(this);
   }
 
@@ -244,7 +244,7 @@ int LIR_Assembler::emit_deopt_handler() {
   // Generate code for deopt handler.
   address handler_base = __ start_a_stub(deopt_handler_size());
 
-  if (handler_base == NULL) {
+  if (handler_base == nullptr) {
     // Not enough space left for the handler.
     bailout("deopt handler overflow");
     return -1;
@@ -261,7 +261,7 @@ int LIR_Assembler::emit_deopt_handler() {
 
 
 void LIR_Assembler::jobject2reg(jobject o, Register reg) {
-  if (o == NULL) {
+  if (o == nullptr) {
     __ li(reg, 0);
   } else {
     AddressLiteral addrlit = __ constant_oop_address(o);
@@ -272,10 +272,10 @@ void LIR_Assembler::jobject2reg(jobject o, Register reg) {
 
 void LIR_Assembler::jobject2reg_with_patching(Register reg, CodeEmitInfo *info) {
   // Allocate a new index in table to hold the object once it's been patched.
-  int oop_index = __ oop_recorder()->allocate_oop_index(NULL);
+  int oop_index = __ oop_recorder()->allocate_oop_index(nullptr);
   PatchingStub* patch = new PatchingStub(_masm, patching_id(info), oop_index);
 
-  AddressLiteral addrlit((address)NULL, oop_Relocation::spec(oop_index));
+  AddressLiteral addrlit((address)nullptr, oop_Relocation::spec(oop_index));
   __ load_const(reg, addrlit, R0);
 
   patching_epilog(patch, lir_patch_normal, reg, info);
@@ -290,10 +290,10 @@ void LIR_Assembler::metadata2reg(Metadata* o, Register reg) {
 
 void LIR_Assembler::klass2reg_with_patching(Register reg, CodeEmitInfo *info) {
   // Allocate a new index in table to hold the klass once it's been patched.
-  int index = __ oop_recorder()->allocate_metadata_index(NULL);
+  int index = __ oop_recorder()->allocate_metadata_index(nullptr);
   PatchingStub* patch = new PatchingStub(_masm, PatchingStub::load_klass_id, index);
 
-  AddressLiteral addrlit((address)NULL, metadata_Relocation::spec(index));
+  AddressLiteral addrlit((address)nullptr, metadata_Relocation::spec(index));
   assert(addrlit.rspec().type() == relocInfo::metadata_type, "must be an metadata reloc");
   __ load_const(reg, addrlit, R0);
 
@@ -446,10 +446,10 @@ void LIR_Assembler::emit_op3(LIR_Op3* op) {
 
 void LIR_Assembler::emit_opBranch(LIR_OpBranch* op) {
 #ifdef ASSERT
-  assert(op->block() == NULL || op->block()->label() == op->label(), "wrong label");
-  if (op->block() != NULL)  _branch_target_blocks.append(op->block());
-  if (op->ublock() != NULL) _branch_target_blocks.append(op->ublock());
-  assert(op->info() == NULL, "shouldn't have CodeEmitInfo");
+  assert(op->block() == nullptr || op->block()->label() == op->label(), "wrong label");
+  if (op->block() != nullptr)  _branch_target_blocks.append(op->block());
+  if (op->ublock() != nullptr) _branch_target_blocks.append(op->ublock());
+  assert(op->info() == nullptr, "shouldn't have CodeEmitInfo");
 #endif
 
   Label *L = op->label();
@@ -459,7 +459,7 @@ void LIR_Assembler::emit_opBranch(LIR_OpBranch* op) {
     Label done;
     bool is_unordered = false;
     if (op->code() == lir_cond_float_branch) {
-      assert(op->ublock() != NULL, "must have unordered successor");
+      assert(op->ublock() != nullptr, "must have unordered successor");
       is_unordered = true;
     } else {
       assert(op->code() == lir_branch, "just checking");
@@ -636,7 +636,7 @@ bool LIR_Assembler::emit_trampoline_stub_for_call(address target, Register Rtoc)
   int start_offset = __ offset();
   // Put the entry point as a constant into the constant pool.
   const address entry_point_toc_addr   = __ address_constant(target, RelocationHolder::none);
-  if (entry_point_toc_addr == NULL) {
+  if (entry_point_toc_addr == nullptr) {
     bailout("const section overflow");
     return false;
   }
@@ -914,7 +914,7 @@ void LIR_Assembler::const2mem(LIR_Opr src, LIR_Opr dest, BasicType type, CodeEmi
   // Null check for large offsets in LIRGenerator::do_StoreField.
   bool needs_explicit_null_check = !ImplicitNullChecks;
 
-  if (info != NULL && needs_explicit_null_check) {
+  if (info != nullptr && needs_explicit_null_check) {
     explicit_null_check(base, info);
   }
 
@@ -934,7 +934,7 @@ void LIR_Assembler::const2mem(LIR_Opr src, LIR_Opr dest, BasicType type, CodeEmi
     }
     case T_OBJECT: {
       tmp = FrameMap::R0_opr;
-      if (UseCompressedOops && !wide && c->as_jobject() != NULL) {
+      if (UseCompressedOops && !wide && c->as_jobject() != nullptr) {
         AddressLiteral oop_addr = __ constant_oop_address(c->as_jobject());
         // Don't care about sign extend (will use stw).
         __ lis(R0, 0); // Will get patched.
@@ -958,7 +958,7 @@ void LIR_Assembler::const2mem(LIR_Opr src, LIR_Opr dest, BasicType type, CodeEmi
     offset = store(tmp, base, addr->disp(), type, wide);
   }
 
-  if (info != NULL) {
+  if (info != nullptr) {
     assert(offset != -1, "offset should've been set");
     if (!needs_explicit_null_check) {
       add_debug_info_for_null_check(offset, info);
@@ -1011,7 +1011,7 @@ void LIR_Assembler::const2reg(LIR_Opr src, LIR_Opr dest, LIR_PatchCode patch_cod
       {
         if (to_reg->is_single_fpu()) {
           address const_addr = __ float_constant(c->as_jfloat());
-          if (const_addr == NULL) {
+          if (const_addr == nullptr) {
             bailout("const section overflow");
             break;
           }
@@ -1030,7 +1030,7 @@ void LIR_Assembler::const2reg(LIR_Opr src, LIR_Opr dest, LIR_PatchCode patch_cod
       {
         if (to_reg->is_double_fpu()) {
           address const_addr = __ double_constant(c->as_jdouble());
-          if (const_addr == NULL) {
+          if (const_addr == nullptr) {
             bailout("const section overflow");
             break;
           }
@@ -1123,7 +1123,7 @@ void LIR_Assembler::mem2reg(LIR_Opr src_opr, LIR_Opr dest, BasicType type,
   // null check for large offsets in LIRGenerator::do_LoadField
   bool needs_explicit_null_check = !os::zero_page_read_protected() || !ImplicitNullChecks;
 
-  if (info != NULL && needs_explicit_null_check) {
+  if (info != nullptr && needs_explicit_null_check) {
     explicit_null_check(src, info);
   }
 
@@ -1131,7 +1131,7 @@ void LIR_Assembler::mem2reg(LIR_Opr src_opr, LIR_Opr dest, BasicType type,
     __ verify_oop(src, FILE_AND_LINE);
   }
 
-  PatchingStub* patch = NULL;
+  PatchingStub* patch = nullptr;
   if (needs_patching) {
     patch = new PatchingStub(_masm, PatchingStub::access_field_id);
     assert(!to_reg->is_double_cpu() ||
@@ -1165,10 +1165,10 @@ void LIR_Assembler::mem2reg(LIR_Opr src_opr, LIR_Opr dest, BasicType type,
     offset = load(src, disp_reg, to_reg, type, wide);
   }
 
-  if (patch != NULL) {
+  if (patch != nullptr) {
     patching_epilog(patch, patch_code, src, info);
   }
-  if (info != NULL && !needs_explicit_null_check) {
+  if (info != nullptr && !needs_explicit_null_check) {
     add_debug_info_for_null_check(offset, info);
   }
 }
@@ -1245,7 +1245,7 @@ void LIR_Assembler::reg2mem(LIR_Opr from_reg, LIR_Opr dest, BasicType type,
   // Null check for large offsets in LIRGenerator::do_StoreField.
   bool needs_explicit_null_check = !ImplicitNullChecks || use_R29;
 
-  if (info != NULL && needs_explicit_null_check) {
+  if (info != nullptr && needs_explicit_null_check) {
     explicit_null_check(src, info);
   }
 
@@ -1253,7 +1253,7 @@ void LIR_Assembler::reg2mem(LIR_Opr from_reg, LIR_Opr dest, BasicType type,
     __ verify_oop(src, FILE_AND_LINE);
   }
 
-  PatchingStub* patch = NULL;
+  PatchingStub* patch = nullptr;
   if (needs_patching) {
     patch = new PatchingStub(_masm, PatchingStub::access_field_id);
     assert(!from_reg->is_double_cpu() ||
@@ -1296,11 +1296,11 @@ void LIR_Assembler::reg2mem(LIR_Opr from_reg, LIR_Opr dest, BasicType type,
     __ load_const_optimized(R29_TOC, MacroAssembler::global_toc(), R0); // reinit
   }
 
-  if (patch != NULL) {
+  if (patch != nullptr) {
     patching_epilog(patch, patch_code, src, info);
   }
 
-  if (info != NULL && !needs_explicit_null_check) {
+  if (info != nullptr && !needs_explicit_null_check) {
     add_debug_info_for_null_check(offset, info);
   }
 }
@@ -1343,7 +1343,7 @@ void LIR_Assembler::return_op(LIR_Opr result, C1SafepointPollStub* code_stub) {
 int LIR_Assembler::safepoint_poll(LIR_Opr tmp, CodeEmitInfo* info) {
   const Register poll_addr = tmp->as_register();
   __ ld(poll_addr, in_bytes(JavaThread::polling_page_offset()), R16_thread);
-  if (info != NULL) {
+  if (info != nullptr) {
     add_debug_info_for_branch(info);
   }
   int offset = __ offset();
@@ -1357,7 +1357,7 @@ int LIR_Assembler::safepoint_poll(LIR_Opr tmp, CodeEmitInfo* info) {
 void LIR_Assembler::emit_static_call_stub() {
   address call_pc = __ pc();
   address stub = __ start_a_stub(static_call_stub_size());
-  if (stub == NULL) {
+  if (stub == nullptr) {
     bailout("static call stub overflow");
     return;
   }
@@ -1379,7 +1379,7 @@ void LIR_Assembler::emit_static_call_stub() {
   // - load the call target from the constant pool
   // - call
   __ calculate_address_from_global_toc(reg_scratch, __ method_toc());
-  AddressLiteral ic = __ allocate_metadata_address((Metadata *)NULL);
+  AddressLiteral ic = __ allocate_metadata_address((Metadata *)nullptr);
   bool success = __ load_const_from_method_toc(R19_inline_cache_reg, ic, reg_scratch, /*fixed_size*/ true);
 
   if (ReoptimizeCallSequences) {
@@ -1435,7 +1435,7 @@ void LIR_Assembler::comp_op(LIR_Condition condition, LIR_Opr opr1, LIR_Opr opr2,
           {
             assert(condition == lir_cond_equal || condition == lir_cond_notEqual, "oops");
             jobject con = opr2->as_constant_ptr()->as_jobject();
-            if (con == NULL) {
+            if (con == nullptr) {
               __ cmpdi(BOOL_RESULT, opr1->as_register(), 0);
             } else {
               jobject2reg(con, R0);
@@ -1445,11 +1445,11 @@ void LIR_Assembler::comp_op(LIR_Condition condition, LIR_Opr opr1, LIR_Opr opr2,
           break;
 
         case T_METADATA:
-          // We only need, for now, comparison with NULL for metadata.
+          // We only need, for now, comparison with null for metadata.
           {
             assert(condition == lir_cond_equal || condition == lir_cond_notEqual, "oops");
             Metadata* p = opr2->as_constant_ptr()->as_metadata();
-            if (p == NULL) {
+            if (p == nullptr) {
               __ cmpdi(BOOL_RESULT, opr1->as_register(), 0);
             } else {
               ShouldNotReachHere();
@@ -1531,7 +1531,7 @@ void LIR_Assembler::comp_fl2i(LIR_Code code, LIR_Opr left, LIR_Opr right, LIR_Op
 
 inline void load_to_reg(LIR_Assembler *lasm, LIR_Opr src, LIR_Opr dst) {
   if (src->is_constant()) {
-    lasm->const2reg(src, dst, lir_patch_none, NULL);
+    lasm->const2reg(src, dst, lir_patch_none, nullptr);
   } else if (src->is_register()) {
     lasm->reg2reg(src, dst);
   } else if (src->is_stack()) {
@@ -1601,7 +1601,7 @@ void LIR_Assembler::cmove(LIR_Condition condition, LIR_Opr opr1, LIR_Opr opr2, L
 
 void LIR_Assembler::arith_op(LIR_Code code, LIR_Opr left, LIR_Opr right, LIR_Opr dest,
                              CodeEmitInfo* info, bool pop_fpu_stack) {
-  assert(info == NULL, "unused on this code path");
+  assert(info == nullptr, "unused on this code path");
   assert(left->is_register(), "wrong items state");
   assert(dest->is_register(), "wrong items state");
 
@@ -1829,7 +1829,7 @@ void LIR_Assembler::emit_arraycopy(LIR_OpArrayCopy* op) {
 
   int flags = op->flags();
   ciArrayKlass* default_type = op->expected_type();
-  BasicType basic_type = default_type != NULL ? default_type->element_type()->basic_type() : T_ILLEGAL;
+  BasicType basic_type = default_type != nullptr ? default_type->element_type()->basic_type() : T_ILLEGAL;
   if (basic_type == T_ARRAY) basic_type = T_OBJECT;
 
   // Set up the arraycopy stub information.
@@ -1840,11 +1840,11 @@ void LIR_Assembler::emit_arraycopy(LIR_OpArrayCopy* op) {
   // the known type isn't loaded since the code sanity checks
   // in debug mode and the type isn't required when we know the exact type
   // also check that the type is an array type.
-  if (op->expected_type() == NULL) {
+  if (op->expected_type() == nullptr) {
     assert(src->is_nonvolatile() && src_pos->is_nonvolatile() && dst->is_nonvolatile() && dst_pos->is_nonvolatile() &&
            length->is_nonvolatile(), "must preserve");
     address copyfunc_addr = StubRoutines::generic_arraycopy();
-    assert(copyfunc_addr != NULL, "generic arraycopy stub required");
+    assert(copyfunc_addr != nullptr, "generic arraycopy stub required");
 
     // 3 parms are int. Convert to long.
     __ mr(R3_ARG1, src);
@@ -1875,7 +1875,7 @@ void LIR_Assembler::emit_arraycopy(LIR_OpArrayCopy* op) {
     return;
   }
 
-  assert(default_type != NULL && default_type->is_array_klass(), "must be true at this point");
+  assert(default_type != nullptr && default_type->is_array_klass(), "must be true at this point");
   Label cont, slow, copyfunc;
 
   bool simple_check_flag_set = flags & (LIR_OpArrayCopy::src_null_check |
@@ -1998,7 +1998,7 @@ void LIR_Assembler::emit_arraycopy(LIR_OpArrayCopy* op) {
       __ load_klass(super_klass, dst);
 
       __ check_klass_subtype_fast_path(sub_klass, super_klass, tmp, tmp2,
-                                       &cont, copyfunc_addr != NULL ? &copyfunc : &slow, NULL);
+                                       &cont, copyfunc_addr != nullptr ? &copyfunc : &slow, nullptr);
 
       address slow_stc = Runtime1::entry_for(Runtime1::slow_subtype_check_id);
       //__ load_const_optimized(tmp, slow_stc, tmp2);
@@ -2007,7 +2007,7 @@ void LIR_Assembler::emit_arraycopy(LIR_OpArrayCopy* op) {
       __ bctrl(); // sets CR0
       __ beq(CCR0, cont);
 
-      if (copyfunc_addr != NULL) { // Use stub if available.
+      if (copyfunc_addr != nullptr) { // Use stub if available.
         __ bind(copyfunc);
         // Src is not a sub class of dst so we have to do a
         // per-element check.
@@ -2348,9 +2348,9 @@ void LIR_Assembler::type_profile_helper(Register mdo, int mdo_offset_bias,
 void LIR_Assembler::setup_md_access(ciMethod* method, int bci,
                                     ciMethodData*& md, ciProfileData*& data, int& mdo_offset_bias) {
   md = method->method_data_or_null();
-  assert(md != NULL, "Sanity");
+  assert(md != nullptr, "Sanity");
   data = md->bci_to_data(bci);
-  assert(data != NULL,       "need data for checkcast");
+  assert(data != nullptr,       "need data for checkcast");
   assert(data->is_ReceiverTypeData(), "need ReceiverTypeData for type check");
   if (!Assembler::is_simm16(md->byte_offset_of_slot(data, DataLayout::header_offset()) + data->size_in_bytes())) {
     // The offset is large so bias the mdo by the base of the slot so
@@ -2384,12 +2384,12 @@ void LIR_Assembler::emit_typecheck_helper(LIR_OpTypeCheck *op, Label* success, L
 
   __ cmpdi(CCR0, obj, 0);
 
-  ciMethodData* md = NULL;
-  ciProfileData* data = NULL;
+  ciMethodData* md = nullptr;
+  ciProfileData* data = nullptr;
   int mdo_offset_bias = 0;
   if (should_profile) {
     ciMethod* method = op->profiled_method();
-    assert(method != NULL, "Should have method");
+    assert(method != nullptr, "Should have method");
     setup_md_access(method, op->profiled_bci(), md, data, mdo_offset_bias);
 
     Register mdo      = k_RInfo;
@@ -2437,8 +2437,8 @@ void LIR_Assembler::emit_typecheck_helper(LIR_OpTypeCheck *op, Label* success, L
         need_slow_path = false;
       }
       // Perform the fast part of the checking logic.
-      __ check_klass_subtype_fast_path(klass_RInfo, k_RInfo, Rtmp1, R0, (need_slow_path ? success_target : NULL),
-                                       failure_target, NULL, RegisterOrConstant(k->super_check_offset()));
+      __ check_klass_subtype_fast_path(klass_RInfo, k_RInfo, Rtmp1, R0, (need_slow_path ? success_target : nullptr),
+                                       failure_target, nullptr, RegisterOrConstant(k->super_check_offset()));
     } else {
       // Perform the fast part of the checking logic.
       __ check_klass_subtype_fast_path(klass_RInfo, k_RInfo, Rtmp1, R0, success_target, failure_target);
@@ -2512,12 +2512,12 @@ void LIR_Assembler::emit_opTypeCheck(LIR_OpTypeCheck* op) {
     __ verify_oop(value, FILE_AND_LINE);
     CodeStub* stub = op->stub();
     // Check if it needs to be profiled.
-    ciMethodData* md = NULL;
-    ciProfileData* data = NULL;
+    ciMethodData* md = nullptr;
+    ciProfileData* data = nullptr;
     int mdo_offset_bias = 0;
     if (should_profile) {
       ciMethod* method = op->profiled_method();
-      assert(method != NULL, "Should have method");
+      assert(method != nullptr, "Should have method");
       setup_md_access(method, op->profiled_bci(), md, data, mdo_offset_bias);
     }
     Label profile_cast_success, failure, done;
@@ -2550,7 +2550,7 @@ void LIR_Assembler::emit_opTypeCheck(LIR_OpTypeCheck* op) {
     // Get instance klass.
     __ ld(k_RInfo, in_bytes(ObjArrayKlass::element_klass_offset()), k_RInfo);
     // Perform the fast part of the checking logic.
-    __ check_klass_subtype_fast_path(klass_RInfo, k_RInfo, Rtmp1, R0, success_target, &failure, NULL);
+    __ check_klass_subtype_fast_path(klass_RInfo, k_RInfo, Rtmp1, R0, success_target, &failure, nullptr);
 
     // Call out-of-line instance of __ check_klass_subtype_slow_path(...):
     const address slow_path = Runtime1::entry_for(Runtime1::slow_subtype_check_id);
@@ -2639,7 +2639,7 @@ void LIR_Assembler::emit_compare_and_swap(LIR_OpCompareAndSwap* op) {
     __ cmpxchgd(BOOL_RESULT, /*current_value=*/R0, cmp_value, new_value, addr,
                 MacroAssembler::MemBarNone,
                 MacroAssembler::cmpxchgx_hint_atomic_update(),
-                noreg, NULL, /*check without ldarx first*/true);
+                noreg, nullptr, /*check without ldarx first*/true);
   } else {
     __ cmpxchgw(BOOL_RESULT, /*current_value=*/R0, cmp_value, new_value, addr,
                 MacroAssembler::MemBarNone,
@@ -2689,7 +2689,7 @@ void LIR_Assembler::emit_lock(LIR_OpLock* op) {
     if (!UseHeavyMonitors) {
       assert(BasicLock::displaced_header_offset_in_bytes() == 0, "lock_reg must point to the displaced header");
       // Add debug info for NullPointerException only if one is possible.
-      if (op->info() != NULL) {
+      if (op->info() != nullptr) {
         if (!os::zero_page_read_protected() || !ImplicitNullChecks) {
           explicit_null_check(obj, op->info());
         } else {
@@ -2704,7 +2704,7 @@ void LIR_Assembler::emit_lock(LIR_OpLock* op) {
       //       simpler and requires less duplicated code - additionally, the
       //       slow locking code is the same in either case which simplifies
       //       debugging.
-      if (op->info() != NULL) {
+      if (op->info() != nullptr) {
         add_debug_info_for_null_check_here(op->info());
         __ null_check(obj);
       }
@@ -2733,7 +2733,7 @@ void LIR_Assembler::emit_load_klass(LIR_OpLoadKlass* op) {
   Register result = op->result_opr()->as_pointer_register();
 
   CodeEmitInfo* info = op->info();
-  if (info != NULL) {
+  if (info != nullptr) {
     if (!os::zero_page_read_protected() || !ImplicitNullChecks) {
       explicit_null_check(obj, info);
     } else {
@@ -2756,9 +2756,9 @@ void LIR_Assembler::emit_profile_call(LIR_OpProfileCall* op) {
 
   // Update counter for all call types.
   ciMethodData* md = method->method_data_or_null();
-  assert(md != NULL, "Sanity");
+  assert(md != nullptr, "Sanity");
   ciProfileData* data = md->bci_to_data(bci);
-  assert(data != NULL && data->is_CounterData(), "need CounterData for calls");
+  assert(data != nullptr && data->is_CounterData(), "need CounterData for calls");
   assert(op->mdo()->is_single_cpu(),  "mdo must be allocated");
   Register mdo = op->mdo()->as_register();
 #ifdef _LP64
@@ -2786,7 +2786,7 @@ void LIR_Assembler::emit_profile_call(LIR_OpProfileCall* op) {
     assert_different_registers(mdo, tmp1, recv);
     assert(data->is_VirtualCallData(), "need VirtualCallData for virtual calls");
     ciKlass* known_klass = op->known_holder();
-    if (C1OptimizeVirtualCallProfiling && known_klass != NULL) {
+    if (C1OptimizeVirtualCallProfiling && known_klass != nullptr) {
       // We know the type that will be seen at this call site; we can
       // statically update the MethodData* rather than needing to do
       // dynamic tests on the receiver type.
@@ -2812,7 +2812,7 @@ void LIR_Assembler::emit_profile_call(LIR_OpProfileCall* op) {
       // VirtualCallData rather than just the first time.
       for (i = 0; i < VirtualCallData::row_limit(); i++) {
         ciKlass* receiver = vc_data->receiver(i);
-        if (receiver == NULL) {
+        if (receiver == nullptr) {
           metadata2reg(known_klass->constant_encoding(), tmp1);
           __ std(tmp1, md->byte_offset_of_slot(data, VirtualCallData::receiver_offset(i)) - mdo_offset_bias, mdo);
 
@@ -2880,14 +2880,14 @@ void LIR_Assembler::rt_call(LIR_Opr result, address dest,
     __ add_const_optimized(R0, R29_TOC, MacroAssembler::offset_to_global_toc(dest));
     __ mtctr(R0);
     __ bctrl();
-    assert(info != NULL, "sanity");
+    assert(info != nullptr, "sanity");
     add_call_info_here(info);
     __ post_call_nop();
     return;
   }
 
   __ call_c_with_frame_resize(dest, /*no resizing*/ 0);
-  if (info != NULL) {
+  if (info != nullptr) {
     add_call_info_here(info);
   }
   __ post_call_nop();
@@ -3072,7 +3072,7 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
   Label Lupdate, Ldo_update, Ldone;
 
   bool do_null = !not_null;
-  bool exact_klass_set = exact_klass != NULL && ciTypeEntries::valid_ciklass(current_klass) == exact_klass;
+  bool exact_klass_set = exact_klass != nullptr && ciTypeEntries::valid_ciklass(current_klass) == exact_klass;
   bool do_update = !TypeEntries::is_type_unknown(current_klass) && !exact_klass_set;
 
   assert(do_null || do_update, "why are we here?");
@@ -3111,7 +3111,7 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
     const Register klass = R29_TOC; // kill and reload
     bool klass_reg_used = false;
 #ifdef ASSERT
-    if (exact_klass != NULL) {
+    if (exact_klass != nullptr) {
       Label ok;
       klass_reg_used = true;
       __ load_klass(klass, obj);
@@ -3124,9 +3124,9 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
 #endif
 
     if (!no_conflict) {
-      if (exact_klass == NULL || TypeEntries::is_type_none(current_klass)) {
+      if (exact_klass == nullptr || TypeEntries::is_type_none(current_klass)) {
         klass_reg_used = true;
-        if (exact_klass != NULL) {
+        if (exact_klass != nullptr) {
           __ ld(tmp, index_or_disp(mdo_addr), mdo_addr->base()->as_pointer_register());
           metadata2reg(exact_klass->constant_encoding(), klass);
         } else {
@@ -3154,7 +3154,7 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
         }
 
       } else {
-        assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
+        assert(ciTypeEntries::valid_ciklass(current_klass) != nullptr &&
                ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "conflict only");
 
         __ ld(tmp, index_or_disp(mdo_addr), mdo_addr->base()->as_pointer_register());
@@ -3167,7 +3167,7 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
       __ ori(R0, tmp, TypeEntries::type_unknown);
     } else {
       // There's a single possible klass at this profile point
-      assert(exact_klass != NULL, "should be");
+      assert(exact_klass != nullptr, "should be");
       __ ld(tmp, index_or_disp(mdo_addr), mdo_addr->base()->as_pointer_register());
 
       if (TypeEntries::is_type_none(current_klass)) {
@@ -3192,7 +3192,7 @@ void LIR_Assembler::emit_profile_type(LIR_OpProfileType* op) {
         // First time here. Set profile type.
         __ orr(R0, klass, tmp); // Combine klass and null_seen bit (only used if (tmp & type_mask)==0).
       } else {
-        assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
+        assert(ciTypeEntries::valid_ciklass(current_klass) != nullptr &&
                ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "inconsistent");
 
         // Already unknown. Nothing to do anymore.
diff --git a/src/hotspot/cpu/ppc/c1_LIRGenerator_ppc.cpp b/src/hotspot/cpu/ppc/c1_LIRGenerator_ppc.cpp
index 2944f6eb645..9ad9933ac2d 100644
--- a/src/hotspot/cpu/ppc/c1_LIRGenerator_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c1_LIRGenerator_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2019 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -108,11 +108,11 @@ LIR_Opr LIRGenerator::rlock_byte(BasicType type) {
 
 // PPC cannot inline all constants.
 bool LIRGenerator::can_store_as_constant(Value v, BasicType type) const {
-  if (v->type()->as_IntConstant() != NULL) {
+  if (v->type()->as_IntConstant() != nullptr) {
     return Assembler::is_simm16(v->type()->as_IntConstant()->value());
-  } else if (v->type()->as_LongConstant() != NULL) {
+  } else if (v->type()->as_LongConstant() != nullptr) {
     return Assembler::is_simm16(v->type()->as_LongConstant()->value());
-  } else if (v->type()->as_ObjectConstant() != NULL) {
+  } else if (v->type()->as_ObjectConstant() != nullptr) {
     return v->type()->as_ObjectConstant()->value()->is_null_object();
   } else {
     return false;
@@ -134,7 +134,7 @@ bool LIRGenerator::can_inline_as_constant(LIR_Const* c) const {
     return Assembler::is_simm16(c->as_jlong());
   }
   if (c->type() == T_OBJECT) {
-    return c->as_jobject() == NULL;
+    return c->as_jobject() == nullptr;
   }
   return false;
 }
@@ -338,7 +338,7 @@ void LIRGenerator::do_MonitorEnter(MonitorEnter* x) {
   LIR_Opr scratch = FrameMap::R4_opr;
   LIR_Opr hdr     = FrameMap::R6_opr;
 
-  CodeEmitInfo* info_for_exception = NULL;
+  CodeEmitInfo* info_for_exception = nullptr;
   if (x->needs_null_check()) {
     info_for_exception = state_for(x);
   }
@@ -395,7 +395,7 @@ void LIRGenerator::do_ArithmeticOp_FPU(ArithmeticOp* x) {
 
   case Bytecodes::_frem:
   case Bytecodes::_drem: {
-    address entry = NULL;
+    address entry = nullptr;
     switch (x->op()) {
     case Bytecodes::_frem:
       entry = CAST_FROM_FN_PTR(address, SharedRuntime::frem);
@@ -406,7 +406,7 @@ void LIRGenerator::do_ArithmeticOp_FPU(ArithmeticOp* x) {
     default:
       ShouldNotReachHere();
     }
-    LIR_Opr result = call_runtime(x->x(), x->y(), entry, x->type(), NULL);
+    LIR_Opr result = call_runtime(x->x(), x->y(), entry, x->type(), nullptr);
     set_result(x, result);
   }
   break;
@@ -457,7 +457,7 @@ void LIRGenerator::do_ArithmeticOp_Long(ArithmeticOp* x) {
   left.load_item();
   rlock_result(x);
   if (is_div_rem) {
-    CodeEmitInfo* info = NULL; // Null check already done above.
+    CodeEmitInfo* info = nullptr; // Null check already done above.
     LIR_Opr tmp = FrameMap::R0_opr;
     if (x->op() == Bytecodes::_lrem) {
       __ irem(left.result(), right.result(), x->operand(), tmp, info);
@@ -465,7 +465,7 @@ void LIRGenerator::do_ArithmeticOp_Long(ArithmeticOp* x) {
       __ idiv(left.result(), right.result(), x->operand(), tmp, info);
     }
   } else {
-    arithmetic_op_long(x->op(), x->operand(), left.result(), right.result(), NULL);
+    arithmetic_op_long(x->op(), x->operand(), left.result(), right.result(), nullptr);
   }
 }
 
@@ -511,7 +511,7 @@ void LIRGenerator::do_ArithmeticOp_Int(ArithmeticOp* x) {
   left.load_item();
   rlock_result(x);
   if (is_div_rem) {
-    CodeEmitInfo* info = NULL; // Null check already done above.
+    CodeEmitInfo* info = nullptr; // Null check already done above.
     LIR_Opr tmp = FrameMap::R0_opr;
     if (x->op() == Bytecodes::_irem) {
       __ irem(left.result(), right.result(), x->operand(), tmp, info);
@@ -741,7 +741,7 @@ void LIRGenerator::do_MathIntrinsic(Intrinsic* x) {
     case vmIntrinsics::_dexp: {
       assert(x->number_of_arguments() == 1, "wrong type");
 
-      address runtime_entry = NULL;
+      address runtime_entry = nullptr;
       switch (x->id()) {
         case vmIntrinsics::_dsqrt:
         case vmIntrinsics::_dsqrt_strict:
@@ -769,14 +769,14 @@ void LIRGenerator::do_MathIntrinsic(Intrinsic* x) {
           ShouldNotReachHere();
       }
 
-      LIR_Opr result = call_runtime(x->argument_at(0), runtime_entry, x->type(), NULL);
+      LIR_Opr result = call_runtime(x->argument_at(0), runtime_entry, x->type(), nullptr);
       set_result(x, result);
       break;
     }
     case vmIntrinsics::_dpow: {
       assert(x->number_of_arguments() == 2, "wrong type");
       address runtime_entry = CAST_FROM_FN_PTR(address, SharedRuntime::dpow);
-      LIR_Opr result = call_runtime(x->argument_at(0), x->argument_at(1), runtime_entry, x->type(), NULL);
+      LIR_Opr result = call_runtime(x->argument_at(0), x->argument_at(1), runtime_entry, x->type(), nullptr);
       set_result(x, result);
       break;
     }
@@ -829,7 +829,7 @@ void LIRGenerator::do_Convert(Convert* x) {
         if (!VM_Version::has_fcfids()) { // fcfids is >= Power7 only
           // fcfid+frsp needs fixup code to avoid rounding incompatibility.
           address entry = CAST_FROM_FN_PTR(address, SharedRuntime::l2f);
-          LIR_Opr result = call_runtime(x->value(), entry, x->type(), NULL);
+          LIR_Opr result = call_runtime(x->value(), entry, x->type(), nullptr);
           set_result(x, result);
           return;
         } // else fallthru
@@ -969,7 +969,7 @@ void LIRGenerator::do_NewObjectArray(NewObjectArray* x) {
   // In case of patching (i.e., object class is not yet loaded),
   // we need to reexecute the instruction and therefore provide
   // the state before the parameters have been consumed.
-  CodeEmitInfo* patching_info = NULL;
+  CodeEmitInfo* patching_info = nullptr;
   if (!x->klass()->is_loaded() || PatchALot) {
     patching_info = state_for(x, x->state_before());
   }
@@ -1005,14 +1005,14 @@ void LIRGenerator::do_NewObjectArray(NewObjectArray* x) {
 void LIRGenerator::do_NewMultiArray(NewMultiArray* x) {
   Values* dims = x->dims();
   int i = dims->length();
-  LIRItemList* items = new LIRItemList(i, i, NULL);
+  LIRItemList* items = new LIRItemList(i, i, nullptr);
   while (i-- > 0) {
     LIRItem* size = new LIRItem(dims->at(i), this);
     items->at_put(i, size);
   }
 
   // Evaluate state_for early since it may emit code.
-  CodeEmitInfo* patching_info = NULL;
+  CodeEmitInfo* patching_info = nullptr;
   if (!x->klass()->is_loaded() || PatchALot) {
     patching_info = state_for(x, x->state_before());
 
@@ -1069,7 +1069,7 @@ void LIRGenerator::do_BlockBegin(BlockBegin* x) {
 
 void LIRGenerator::do_CheckCast(CheckCast* x) {
   LIRItem obj(x->obj(), this);
-  CodeEmitInfo* patching_info = NULL;
+  CodeEmitInfo* patching_info = nullptr;
   if (!x->klass()->is_loaded() || (PatchALot && !x->is_incompatible_class_change_check() && !x->is_invokespecial_receiver_check())) {
     // Must do this before locking the destination register as
     // an oop register, and before the obj is loaded (so x->obj()->item()
@@ -1084,11 +1084,11 @@ void LIRGenerator::do_CheckCast(CheckCast* x) {
                                     state_for(x, x->state_before(), true /*ignore_xhandler*/));
 
   if (x->is_incompatible_class_change_check()) {
-    assert(patching_info == NULL, "can't patch this");
+    assert(patching_info == nullptr, "can't patch this");
     stub = new SimpleExceptionStub(Runtime1::throw_incompatible_class_change_error_id,
                                    LIR_OprFact::illegalOpr, info_for_exception);
   } else if (x->is_invokespecial_receiver_check()) {
-    assert(patching_info == NULL, "can't patch this");
+    assert(patching_info == nullptr, "can't patch this");
     stub = new DeoptimizeStub(info_for_exception,
                               Deoptimization::Reason_class_check,
                               Deoptimization::Action_none);
@@ -1107,7 +1107,7 @@ void LIRGenerator::do_CheckCast(CheckCast* x) {
 
 void LIRGenerator::do_InstanceOf(InstanceOf* x) {
   LIRItem obj(x->obj(), this);
-  CodeEmitInfo* patching_info = NULL;
+  CodeEmitInfo* patching_info = nullptr;
   if (!x->klass()->is_loaded() || PatchALot) {
     patching_info = state_for(x, x->state_before());
   }
@@ -1248,7 +1248,7 @@ void LIRGenerator::do_update_CRC32(Intrinsic* x) {
         offset += off.result()->as_jint();
       }
       LIR_Opr base_op = buf.result();
-      LIR_Address* a = NULL;
+      LIR_Address* a = nullptr;
 
       if (index->is_valid()) {
         LIR_Opr tmp = new_register(T_LONG);
@@ -1318,7 +1318,7 @@ void LIRGenerator::do_update_CRC32C(Intrinsic* x) {
         offset += off.result()->as_jint();
       }
       LIR_Opr base_op = buf.result();
-      LIR_Address* a = NULL;
+      LIR_Address* a = nullptr;
 
       if (index->is_valid()) {
         LIR_Opr tmp = new_register(T_LONG);
diff --git a/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp b/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp
index d3b4e19fcb1..c1396843e00 100644
--- a/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp
@@ -399,7 +399,7 @@ void C1_MacroAssembler::null_check(Register r, Label* Lnull) {
     trap_null_check(r);
   } else { // explicit
     //const address exception_entry = Runtime1::entry_for(Runtime1::throw_null_pointer_exception_id);
-    assert(Lnull != NULL, "must have Label for explicit check");
+    assert(Lnull != nullptr, "must have Label for explicit check");
     cmpdi(CCR0, r, 0);
     bc_far_optimized(Assembler::bcondCRbiIs1, bi0(CCR0, Assembler::equal), *Lnull);
   }
diff --git a/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.hpp b/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.hpp
index f0a6707d1ae..5fa19d5fd5d 100644
--- a/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -86,7 +86,7 @@
     Label&   slow_case                 // continuation point if fast allocation fails
   );
 
-  void null_check(Register r, Label *Lnull = NULL);
+  void null_check(Register r, Label *Lnull = nullptr);
 
   address call_c_with_frame_resize(address dest, int frame_resize);
 
diff --git a/src/hotspot/cpu/ppc/c1_Runtime1_ppc.cpp b/src/hotspot/cpu/ppc/c1_Runtime1_ppc.cpp
index 485ab506597..b3b68034e7a 100644
--- a/src/hotspot/cpu/ppc/c1_Runtime1_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c1_Runtime1_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -370,7 +370,7 @@ OopMapSet* Runtime1::generate_patching(StubAssembler* sasm, address target) {
   // return to the deoptimization handler entry that will cause re-execution
   // of the current bytecode.
   DeoptimizationBlob* deopt_blob = SharedRuntime::deopt_blob();
-  assert(deopt_blob != NULL, "deoptimization blob must have been created");
+  assert(deopt_blob != nullptr, "deoptimization blob must have been created");
 
   // Return to the deoptimization handler entry for unpacking and rexecute.
   // If we simply returned the we'd deopt as if any call we patched had just
@@ -390,7 +390,7 @@ OopMapSet* Runtime1::generate_patching(StubAssembler* sasm, address target) {
 }
 
 OopMapSet* Runtime1::generate_code_for(StubID id, StubAssembler* sasm) {
-  OopMapSet* oop_maps = NULL;
+  OopMapSet* oop_maps = nullptr;
 
   // For better readability.
   const bool must_gc_arguments = true;
@@ -648,7 +648,7 @@ OopMapSet* Runtime1::generate_code_for(StubID id, StubAssembler* sasm) {
         oop_maps = stub_call_with_stack_parms(sasm, noreg, CAST_FROM_FN_PTR(address, deoptimize), 1, /*do_return*/ false);
 
         DeoptimizationBlob* deopt_blob = SharedRuntime::deopt_blob();
-        assert(deopt_blob != NULL, "deoptimization blob must have been created");
+        assert(deopt_blob != nullptr, "deoptimization blob must have been created");
         address stub = deopt_blob->unpack_with_reexecution();
         //__ load_const_optimized(R0, stub);
         __ add_const_optimized(R0, R29_TOC, MacroAssembler::offset_to_global_toc(stub));
@@ -716,7 +716,7 @@ OopMapSet* Runtime1::generate_code_for(StubID id, StubAssembler* sasm) {
         oop_maps->add_gc_map(call_offset, oop_map);
 
         DeoptimizationBlob* deopt_blob = SharedRuntime::deopt_blob();
-        assert(deopt_blob != NULL, "deoptimization blob must have been created");
+        assert(deopt_blob != nullptr, "deoptimization blob must have been created");
         restore_live_registers(sasm, noreg, noreg);
 
         address stub = deopt_blob->unpack_with_reexecution();
@@ -754,7 +754,7 @@ OopMapSet* Runtime1::generate_handle_exception(StubID id, StubAssembler* sasm) {
 
   // Save registers, if required.
   OopMapSet* oop_maps = new OopMapSet();
-  OopMap* oop_map = NULL;
+  OopMap* oop_map = nullptr;
   const Register Rexception    = R3 /*LIRGenerator::exceptionOopOpr()*/,
                  Rexception_pc = R4 /*LIRGenerator::exceptionPcOpr()*/;
 
diff --git a/src/hotspot/cpu/ppc/c2_CodeStubs_ppc.cpp b/src/hotspot/cpu/ppc/c2_CodeStubs_ppc.cpp
index f99f9e978cf..93ee0659a57 100644
--- a/src/hotspot/cpu/ppc/c2_CodeStubs_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c2_CodeStubs_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2021, 2022, SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -35,7 +35,7 @@ int C2SafepointPollStub::max_size() const {
 }
 
 void C2SafepointPollStub::emit(C2_MacroAssembler& masm) {
-  assert(SharedRuntime::polling_page_return_handler_blob() != NULL,
+  assert(SharedRuntime::polling_page_return_handler_blob() != nullptr,
          "polling page return stub not created yet");
   address stub = SharedRuntime::polling_page_return_handler_blob()->entry_point();
 
diff --git a/src/hotspot/cpu/ppc/c2_MacroAssembler_ppc.cpp b/src/hotspot/cpu/ppc/c2_MacroAssembler_ppc.cpp
index 30104094983..d504c71e2b8 100644
--- a/src/hotspot/cpu/ppc/c2_MacroAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/c2_MacroAssembler_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2023, Oracle and/or its affiliates. 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
@@ -301,7 +301,7 @@ void C2_MacroAssembler::array_equals(bool is_array_equ, Register ary1, Register
     cmpd(CCR0, ary1, ary2);
     beq(CCR0, Lskiploop);
 
-    // Return false if one of them is NULL.
+    // Return false if one of them is null.
     cmpdi(CCR0, ary1, 0);
     cmpdi(CCR1, ary2, 0);
     li(result, 0);
diff --git a/src/hotspot/cpu/ppc/compiledIC_ppc.cpp b/src/hotspot/cpu/ppc/compiledIC_ppc.cpp
index a112e472e4b..2e5548afcb1 100644
--- a/src/hotspot/cpu/ppc/compiledIC_ppc.cpp
+++ b/src/hotspot/cpu/ppc/compiledIC_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -79,9 +79,9 @@
 
 const int IC_pos_in_java_to_interp_stub = 8;
 #define __ _masm.
-address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/* = NULL*/) {
+address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/* = nullptr*/) {
 #ifdef COMPILER2
-  if (mark == NULL) {
+  if (mark == nullptr) {
     // Get the mark within main instrs section which is set to the address of the call.
     mark = cbuf.insts_mark();
   }
@@ -92,8 +92,8 @@ address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/*
 
   // Start the stub.
   address stub = __ start_a_stub(CompiledStaticCall::to_interp_stub_size());
-  if (stub == NULL) {
-    return NULL; // CodeCache is full
+  if (stub == nullptr) {
+    return nullptr; // CodeCache is full
   }
 
   // For java_to_interp stubs we use R11_scratch1 as scratch register
@@ -113,11 +113,11 @@ address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/*
   // - load the call target from the constant pool
   // - call
   __ calculate_address_from_global_toc(reg_scratch, __ method_toc());
-  AddressLiteral ic = __ allocate_metadata_address((Metadata *)NULL);
+  AddressLiteral ic = __ allocate_metadata_address((Metadata *)nullptr);
   bool success = __ load_const_from_method_toc(as_Register(Matcher::inline_cache_reg_encode()),
                                                ic, reg_scratch, /*fixed_size*/ true);
   if (!success) {
-    return NULL; // CodeCache is full
+    return nullptr; // CodeCache is full
   }
 
   if (ReoptimizeCallSequences) {
@@ -126,7 +126,7 @@ address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/*
     AddressLiteral a((address)-1);
     success = __ load_const_from_method_toc(reg_scratch, a, reg_scratch, /*fixed_size*/ true);
     if (!success) {
-      return NULL; // CodeCache is full
+      return nullptr; // CodeCache is full
     }
     __ mtctr(reg_scratch);
     __ bctr();
@@ -145,7 +145,7 @@ address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/*
   return stub;
 #else
   ShouldNotReachHere();
-  return NULL;
+  return nullptr;
 #endif
 }
 #undef __
@@ -165,7 +165,7 @@ int CompiledStaticCall::reloc_to_interp_stub() {
 
 void CompiledDirectStaticCall::set_to_interpreted(const methodHandle& callee, address entry) {
   address stub = find_stub();
-  guarantee(stub != NULL, "stub not found");
+  guarantee(stub != nullptr, "stub not found");
 
   if (TraceICs) {
     ResourceMark rm;
@@ -191,7 +191,7 @@ void CompiledDirectStaticCall::set_to_interpreted(const methodHandle& callee, ad
 void CompiledDirectStaticCall::set_stub_to_clean(static_stub_Relocation* static_stub) {
   // Reset stub.
   address stub = static_stub->addr();
-  assert(stub != NULL, "stub not found");
+  assert(stub != nullptr, "stub not found");
   assert(CompiledICLocker::is_safe(stub), "mt unsafe call");
   // Creation also verifies the object.
   NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);
@@ -211,7 +211,7 @@ void CompiledDirectStaticCall::verify() {
 
   // Verify stub.
   address stub = find_stub();
-  assert(stub != NULL, "no stub found for static call");
+  assert(stub != nullptr, "no stub found for static call");
   // Creation also verifies the object.
   NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);
   NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());
diff --git a/src/hotspot/cpu/ppc/continuationFreezeThaw_ppc.inline.hpp b/src/hotspot/cpu/ppc/continuationFreezeThaw_ppc.inline.hpp
index 9541f96efcb..0bef7b68d07 100644
--- a/src/hotspot/cpu/ppc/continuationFreezeThaw_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/continuationFreezeThaw_ppc.inline.hpp
@@ -533,7 +533,7 @@ template<typename FKind> frame ThawBase::new_stack_frame(const frame& hf, frame&
 
 inline intptr_t* ThawBase::align(const frame& hf, intptr_t* frame_sp, frame& caller, bool bottom) {
   // Unused. Alignment is done directly in new_stack_frame() / finish_thaw().
-  return NULL;
+  return nullptr;
 }
 
 static inline void derelativize_one(intptr_t* const fp, int offset) {
diff --git a/src/hotspot/cpu/ppc/continuationHelper_ppc.inline.hpp b/src/hotspot/cpu/ppc/continuationHelper_ppc.inline.hpp
index c2a592a27f7..f2a1ef828c9 100644
--- a/src/hotspot/cpu/ppc/continuationHelper_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/continuationHelper_ppc.inline.hpp
@@ -30,7 +30,7 @@
 template<typename FKind>
 static inline intptr_t** link_address(const frame& f) {
   Unimplemented();
-  return NULL;
+  return nullptr;
 }
 
 inline int ContinuationHelper::frame_align_words(int size) {
diff --git a/src/hotspot/cpu/ppc/disassembler_ppc.hpp b/src/hotspot/cpu/ppc/disassembler_ppc.hpp
index 7f650ee2d35..18d075f40c7 100644
--- a/src/hotspot/cpu/ppc/disassembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/disassembler_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2019 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -39,7 +39,7 @@
   // the perfect job. In those cases, decode_instruction0 may kick in
   // and do it right.
   // If nothing had to be done, just return "here", otherwise return "here + instr_len(here)"
-  static address decode_instruction0(address here, outputStream* st, address virtual_begin = NULL);
+  static address decode_instruction0(address here, outputStream* st, address virtual_begin = nullptr);
 
   // platform-specific instruction annotations (like value of loaded constants)
   static void annotate(address pc, outputStream* st);
diff --git a/src/hotspot/cpu/ppc/frame_ppc.cpp b/src/hotspot/cpu/ppc/frame_ppc.cpp
index e7fe7669e08..0657da07deb 100644
--- a/src/hotspot/cpu/ppc/frame_ppc.cpp
+++ b/src/hotspot/cpu/ppc/frame_ppc.cpp
@@ -82,7 +82,7 @@ bool frame::safe_for_sender(JavaThread *thread) {
   // construct the sender and do some validation of it. This goes a long way
   // toward eliminating issues when we get in frame construction code
 
-  if (_cb != NULL) {
+  if (_cb != nullptr) {
 
     // First check if the frame is complete and the test is reliable.
     // Unfortunately we can only check frame completeness for runtime stubs
@@ -111,7 +111,7 @@ bool frame::safe_for_sender(JavaThread *thread) {
     }
 
     // At this point, there still is a chance that fp_safe is false.
-    // In particular, (fp == NULL) might be true. So let's check and
+    // In particular, fp might be null. So let's check and
     // bail out before we actually dereference from fp.
     if (!fp_safe) {
       return false;
@@ -130,7 +130,7 @@ bool frame::safe_for_sender(JavaThread *thread) {
 
     // We must always be able to find a recognizable pc.
     CodeBlob* sender_blob = CodeCache::find_blob(sender_pc);
-    if (sender_blob == NULL) {
+    if (sender_blob == nullptr) {
       return false;
     }
 
@@ -186,7 +186,7 @@ bool frame::safe_for_sender(JavaThread *thread) {
 }
 
 frame frame::sender_for_entry_frame(RegisterMap *map) const {
-  assert(map != NULL, "map must be set");
+  assert(map != nullptr, "map must be set");
   // Java frame called from C; skip all C frames and return top C
   // frame of that chunk as the sender.
   JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
@@ -195,7 +195,7 @@ frame frame::sender_for_entry_frame(RegisterMap *map) const {
   map->clear();
   assert(map->include_argument_oops(), "should be set by clear");
 
-  if (jfa->last_Java_pc() != NULL) {
+  if (jfa->last_Java_pc() != nullptr) {
     frame fr(jfa->last_Java_sp(), jfa->last_Java_pc());
     return fr;
   }
@@ -262,7 +262,7 @@ void frame::patch_pc(Thread* thread, address pc) {
   own_abi()->lr = (uint64_t)pc;
   _pc = pc; // must be set before call to get_deopt_original_pc
   address original_pc = CompiledMethod::get_deopt_original_pc(this);
-  if (original_pc != NULL) {
+  if (original_pc != nullptr) {
     assert(original_pc == old_pc, "expected original PC to be stored before patching");
     _deopt_state = is_deoptimized;
     _pc = original_pc;
diff --git a/src/hotspot/cpu/ppc/frame_ppc.inline.hpp b/src/hotspot/cpu/ppc/frame_ppc.inline.hpp
index a2aa9a7be69..c36b6c6e4da 100644
--- a/src/hotspot/cpu/ppc/frame_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/frame_ppc.inline.hpp
@@ -127,7 +127,7 @@ inline frame::frame(intptr_t* sp, intptr_t* unextended_sp, intptr_t* fp, address
 // Accessors
 
 // Return unique id for this frame. The id must have a value where we
-// can distinguish identity and younger/older relationship. NULL
+// can distinguish identity and younger/older relationship. null
 // represents an invalid (incomparable) frame.
 inline intptr_t* frame::id(void) const {
   // Use _fp. _sp or _unextended_sp wouldn't be correct due to resizing.
@@ -137,7 +137,7 @@ inline intptr_t* frame::id(void) const {
 // Return true if this frame is older (less recent activation) than
 // the frame represented by id.
 inline bool frame::is_older(intptr_t* id) const {
-   assert(this->id() != NULL && id != NULL, "NULL frame id");
+   assert(this->id() != nullptr && id != nullptr, "null frame id");
    // Stack grows towards smaller addresses on ppc64.
    return this->id() > id;
 }
@@ -320,7 +320,7 @@ inline frame frame::sender_for_compiled_frame(RegisterMap *map) const {
     } else {
       assert(!_cb->caller_must_gc_arguments(map->thread()), "");
       assert(!map->include_argument_oops(), "");
-      assert(oop_map() == NULL || !oop_map()->has_any(OopMapValue::callee_saved_value), "callee-saved value in compiled frame");
+      assert(oop_map() == nullptr || !oop_map()->has_any(OopMapValue::callee_saved_value), "callee-saved value in compiled frame");
     }
   }
 
@@ -339,29 +339,29 @@ inline frame frame::sender_for_compiled_frame(RegisterMap *map) const {
 
 inline oop frame::saved_oop_result(RegisterMap* map) const {
   oop* result_adr = (oop *)map->location(R3->as_VMReg(), sp());
-  guarantee(result_adr != NULL, "bad register save location");
+  guarantee(result_adr != nullptr, "bad register save location");
   return *result_adr;
 }
 
 inline void frame::set_saved_oop_result(RegisterMap* map, oop obj) {
   oop* result_adr = (oop *)map->location(R3->as_VMReg(), sp());
-  guarantee(result_adr != NULL, "bad register save location");
+  guarantee(result_adr != nullptr, "bad register save location");
 
   *result_adr = obj;
 }
 
 inline const ImmutableOopMap* frame::get_oop_map() const {
-  if (_cb == NULL) return NULL;
-  if (_cb->oop_maps() != NULL) {
+  if (_cb == nullptr) return nullptr;
+  if (_cb->oop_maps() != nullptr) {
     NativePostCallNop* nop = nativePostCallNop_at(_pc);
-    if (nop != NULL && nop->displacement() != 0) {
+    if (nop != nullptr && nop->displacement() != 0) {
       int slot = ((nop->displacement() >> 24) & 0xff);
       return _cb->oop_map_for_slot(slot, _pc);
     }
     const ImmutableOopMap* oop_map = OopMapSet::find_map(this);
     return oop_map;
   }
-  return NULL;
+  return nullptr;
 }
 
 inline int frame::compiled_frame_stack_argsize() const {
@@ -370,7 +370,7 @@ inline int frame::compiled_frame_stack_argsize() const {
 }
 
 inline void frame::interpreted_frame_oop_map(InterpreterOopMap* mask) const {
-  assert(mask != NULL, "");
+  assert(mask != nullptr, "");
   Method* m = interpreter_frame_method();
   int   bci = interpreter_frame_bci();
   m->mask_for(bci, mask); // OopMapCache::compute_one_oop_map(m, bci, mask);
diff --git a/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.cpp b/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.cpp
index bda0cff3429..ac988dcad1b 100644
--- a/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.cpp
@@ -246,7 +246,7 @@ void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm, Decorato
   __ srdi_(tmp1, tmp1, HeapRegion::LogOfHRGrainBytes);
   __ beq(CCR0, filtered);
 
-  // Crosses regions, storing NULL?
+  // Crosses regions, storing null?
   if (not_null) {
 #ifdef ASSERT
     __ cmpdi(CCR0, new_val, 0);
@@ -257,7 +257,7 @@ void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm, Decorato
     __ beq(CCR0, filtered);
   }
 
-  // Storing region crossing non-NULL, is card already dirty?
+  // Storing region crossing non-null, is card already dirty?
   const Register Rcard_addr = tmp1;
   Register Rbase = tmp2;
   __ load_const_optimized(Rbase, (address)(ct->card_table()->byte_map_base()), /*temp*/ tmp3);
@@ -274,7 +274,7 @@ void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm, Decorato
   __ cmpwi(CCR0, tmp3 /* card value */, (int)G1CardTable::dirty_card_val());
   __ beq(CCR0, filtered);
 
-  // Storing a region crossing, non-NULL oop, card is clean.
+  // Storing a region crossing, non-null oop, card is clean.
   // Dirty card and log.
   __ li(tmp3, (int)G1CardTable::dirty_card_val());
   //release(); // G1: oops are allowed to get visible after dirty marking.
@@ -325,7 +325,7 @@ void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet deco
                                 tmp1, tmp2, tmp3,
                                 preservation_level);
 
-  // No need for post barrier if storing NULL
+  // No need for post barrier if storing null
   if (val != noreg) {
     if (precise) {
       if (ind_or_offs.is_constant()) {
@@ -350,7 +350,7 @@ void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorator
   bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
   bool on_reference = on_weak || on_phantom;
   Label done;
-  if (on_oop && on_reference && L_handle_null == NULL) { L_handle_null = &done; }
+  if (on_oop && on_reference && L_handle_null == nullptr) { L_handle_null = &done; }
   // Load the value of the referent field.
   ModRefBarrierSetAssembler::load_at(masm, decorators, type,
                                      base, ind_or_offs, dst,
@@ -375,7 +375,7 @@ void G1BarrierSetAssembler::resolve_jobject(MacroAssembler* masm, Register value
                                             MacroAssembler::PreservationLevel preservation_level) {
   Label done, not_weak;
   __ cmpdi(CCR0, value, 0);
-  __ beq(CCR0, done);         // Use NULL as-is.
+  __ beq(CCR0, done);         // Use null as-is.
 
   __ clrrdi(tmp1, value, JNIHandles::tag_size);
   __ andi_(tmp2, value, JNIHandles::TypeTag::weak_global);
diff --git a/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.hpp b/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.hpp
index 1d522c9e223..d9a252ff6ea 100644
--- a/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/gc/g1/g1BarrierSetAssembler_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -71,7 +71,7 @@ public:
                        Register base, RegisterOrConstant ind_or_offs, Register dst,
                        Register tmp1, Register tmp2,
                        MacroAssembler::PreservationLevel preservation_level,
-                       Label *L_handle_null = NULL);
+                       Label *L_handle_null = nullptr);
 
   virtual void resolve_jobject(MacroAssembler* masm, Register value,
                                Register tmp1, Register tmp2,
diff --git a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.cpp b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.cpp
index f507c290aa1..fbe37a0a35c 100644
--- a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.cpp
@@ -85,7 +85,7 @@ void BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators,
   case T_ARRAY:
   case T_OBJECT: {
     if (UseCompressedOops && in_heap) {
-      if (L_handle_null != NULL) { // Label provided.
+      if (L_handle_null != nullptr) { // Label provided.
         __ lwz(dst, ind_or_offs, base);
         __ cmpwi(CCR0, dst, 0);
         __ beq(CCR0, *L_handle_null);
@@ -100,7 +100,7 @@ void BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators,
       }
     } else {
       __ ld(dst, ind_or_offs, base);
-      if (L_handle_null != NULL) {
+      if (L_handle_null != nullptr) {
         __ cmpdi(CCR0, dst, 0);
         __ beq(CCR0, *L_handle_null);
       }
@@ -117,7 +117,7 @@ void BarrierSetAssembler::resolve_jobject(MacroAssembler* masm, Register value,
                                           MacroAssembler::PreservationLevel preservation_level) {
   Label done, tagged, weak_tagged, verify;
   __ cmpdi(CCR0, value, 0);
-  __ beq(CCR0, done);         // Use NULL as-is.
+  __ beq(CCR0, done);         // Use null as-is.
 
   __ andi_(tmp1, value, JNIHandles::tag_mask);
   __ bne(CCR0, tagged);       // Test for tag.
@@ -151,7 +151,7 @@ void BarrierSetAssembler::resolve_global_jobject(MacroAssembler* masm, Register
   Label done;
 
   __ cmpdi(CCR0, value, 0);
-  __ beq(CCR0, done);         // Use NULL as-is.
+  __ beq(CCR0, done);         // Use null as-is.
 
 #ifdef ASSERT
   {
diff --git a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
index 0265f97b639..eeb5dcce940 100644
--- a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
@@ -51,7 +51,7 @@ public:
   virtual void load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                        Register base, RegisterOrConstant ind_or_offs, Register dst,
                        Register tmp1, Register tmp2,
-                       MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = NULL);
+                       MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = nullptr);
 
   virtual void resolve_jobject(MacroAssembler* masm, Register value,
                                Register tmp1, Register tmp2,
diff --git a/src/hotspot/cpu/ppc/gc/shared/cardTableBarrierSetAssembler_ppc.cpp b/src/hotspot/cpu/ppc/gc/shared/cardTableBarrierSetAssembler_ppc.cpp
index 0d80f2fd954..c9b6b94e1ee 100644
--- a/src/hotspot/cpu/ppc/gc/shared/cardTableBarrierSetAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/shared/cardTableBarrierSetAssembler_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -97,7 +97,7 @@ void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorS
                                 tmp1, tmp2, tmp3,
                                 preservation_level);
 
-  // No need for post barrier if storing NULL
+  // No need for post barrier if storing null
   if (val != noreg) {
     if (precise) {
       if (ind_or_offs.is_constant()) {
diff --git a/src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.cpp b/src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.cpp
index baa7a117b62..a500a078c2d 100644
--- a/src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.cpp
@@ -82,7 +82,7 @@ void ModRefBarrierSetAssembler::resolve_jobject(MacroAssembler* masm, Register v
                                                 MacroAssembler::PreservationLevel preservation_level) {
   Label done;
   __ cmpdi(CCR0, value, 0);
-  __ beq(CCR0, done);         // Use NULL as-is.
+  __ beq(CCR0, done);         // Use null as-is.
 
   __ clrrdi(tmp1, value, JNIHandles::tag_size);
   __ ld(value, 0, tmp1);      // Resolve (untagged) jobject.
diff --git a/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.cpp b/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.cpp
index e7739ffcac0..ec91e86cd7c 100644
--- a/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.cpp
@@ -156,7 +156,7 @@ void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler *masm, Dec
   }
 
   // Invoke runtime.
-  address jrt_address = NULL;
+  address jrt_address = nullptr;
   if (UseCompressedOops) {
     jrt_address = CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop_entry);
   } else {
@@ -686,7 +686,7 @@ void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler *masm, Register b
                 false, success_flag, true);
   } else {
     __ cmpxchgd(CCR0, current_value, expected, new_val, base_addr, MacroAssembler::MemBarNone,
-                false, success_flag, NULL, true);
+                false, success_flag, nullptr, true);
   }
 
   // Skip the rest of the barrier if the CAS operation succeeds immediately.
@@ -963,7 +963,7 @@ void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_s
   bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
   bool is_native  = ShenandoahBarrierSet::is_native_access(decorators);
 
-  address jrt_address = NULL;
+  address jrt_address = nullptr;
 
   if (is_strong) {
     if (is_native) {
@@ -987,7 +987,7 @@ void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_s
     assert(is_native, "phantom load reference barrier must be called off-heap");
     jrt_address = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
   }
-  assert(jrt_address != NULL, "load reference barrier runtime routine cannot be found");
+  assert(jrt_address != nullptr, "load reference barrier runtime routine cannot be found");
 
   __ save_LR_CR(R11_tmp);
   __ push_frame_reg_args(nbytes_save, R11_tmp);
diff --git a/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.hpp b/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.hpp
index 931b02c2a83..4514f2540ac 100644
--- a/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.hpp
@@ -110,7 +110,7 @@ public:
   virtual void load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                        Register base, RegisterOrConstant ind_or_offs, Register dst,
                        Register tmp1, Register tmp2,
-                       MacroAssembler::PreservationLevel preservation_level, Label* L_handle_null = NULL);
+                       MacroAssembler::PreservationLevel preservation_level, Label* L_handle_null = nullptr);
 
   virtual void try_resolve_jobject_in_native(MacroAssembler* masm, Register dst, Register jni_env,
                                              Register obj, Register tmp, Label& slowpath);
diff --git a/src/hotspot/cpu/ppc/gc/z/zBarrierSetAssembler_ppc.hpp b/src/hotspot/cpu/ppc/gc/z/zBarrierSetAssembler_ppc.hpp
index 95df6152d07..808edca6939 100644
--- a/src/hotspot/cpu/ppc/gc/z/zBarrierSetAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/gc/z/zBarrierSetAssembler_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2021, 2022 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -48,7 +48,7 @@ public:
   virtual void load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                        Register base, RegisterOrConstant ind_or_offs, Register dst,
                        Register tmp1, Register tmp2,
-                       MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = NULL);
+                       MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = nullptr);
 
 #ifdef ASSERT
   virtual void store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
diff --git a/src/hotspot/cpu/ppc/globals_ppc.hpp b/src/hotspot/cpu/ppc/globals_ppc.hpp
index 547302b37f2..c33aee3c125 100644
--- a/src/hotspot/cpu/ppc/globals_ppc.hpp
+++ b/src/hotspot/cpu/ppc/globals_ppc.hpp
@@ -34,7 +34,7 @@
 
 define_pd_global(bool, ImplicitNullChecks,    true);  // Generate code for implicit null checks.
 define_pd_global(bool, TrapBasedNullChecks,   true);
-define_pd_global(bool, UncommonNullCast,      true);  // Uncommon-trap NULLs passed to check cast.
+define_pd_global(bool, UncommonNullCast,      true);  // Uncommon-trap nulls passed to check cast.
 
 define_pd_global(bool, DelayCompilerStubsGeneration, COMPILER2_OR_JVMCI);
 
diff --git a/src/hotspot/cpu/ppc/interp_masm_ppc.hpp b/src/hotspot/cpu/ppc/interp_masm_ppc.hpp
index 14042588886..928c48cdd17 100644
--- a/src/hotspot/cpu/ppc/interp_masm_ppc.hpp
+++ b/src/hotspot/cpu/ppc/interp_masm_ppc.hpp
@@ -79,7 +79,7 @@ class InterpreterMacroAssembler: public MacroAssembler {
 
   // Load object from cpool->resolved_references(index).
   void load_resolved_reference_at_index(Register result, Register index, Register tmp1, Register tmp2,
-                                        Label *L_handle_null = NULL);
+                                        Label *L_handle_null = nullptr);
 
   // load cpool->resolved_klass_at(index)
   void load_resolved_klass_at_offset(Register Rcpool, Register Roffset, Register Rklass);
diff --git a/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp b/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp
index e586c74ee5a..be1611739c5 100644
--- a/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp
+++ b/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp
@@ -932,7 +932,7 @@ void InterpreterMacroAssembler::lock_object(Register monitor, Register object) {
     //   // We stored the monitor address into the object's mark word.
     // } else if (THREAD->is_lock_owned((address)displaced_header))
     //   // Simple recursive case.
-    //   monitor->lock()->set_displaced_header(NULL);
+    //   monitor->lock()->set_displaced_header(nullptr);
     // } else {
     //   // Slow path.
     //   InterpreterRuntime::monitorenter(THREAD, monitor);
@@ -993,7 +993,7 @@ void InterpreterMacroAssembler::lock_object(Register monitor, Register object) {
 
     // } else if (THREAD->is_lock_owned((address)displaced_header))
     //   // Simple recursive case.
-    //   monitor->lock()->set_displaced_header(NULL);
+    //   monitor->lock()->set_displaced_header(nullptr);
 
     // We did not see an unlocked object so try the fast recursive case.
 
@@ -1043,12 +1043,12 @@ void InterpreterMacroAssembler::unlock_object(Register monitor) {
 
     // template code:
     //
-    // if ((displaced_header = monitor->displaced_header()) == NULL) {
-    //   // Recursive unlock. Mark the monitor unlocked by setting the object field to NULL.
-    //   monitor->set_obj(NULL);
+    // if ((displaced_header = monitor->displaced_header()) == nullptr) {
+    //   // Recursive unlock. Mark the monitor unlocked by setting the object field to null.
+    //   monitor->set_obj(nullptr);
     // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
     //   // We swapped the unlocked mark in displaced_header into the object's mark word.
-    //   monitor->set_obj(NULL);
+    //   monitor->set_obj(nullptr);
     // } else {
     //   // Slow path.
     //   InterpreterRuntime::monitorexit(monitor);
@@ -1074,7 +1074,7 @@ void InterpreterMacroAssembler::unlock_object(Register monitor) {
 
     // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
     //   // We swapped the unlocked mark in displaced_header into the object's mark word.
-    //   monitor->set_obj(NULL);
+    //   monitor->set_obj(nullptr);
 
     // If we still have a lightweight lock, unlock the object and be done.
 
@@ -1109,7 +1109,7 @@ void InterpreterMacroAssembler::unlock_object(Register monitor) {
     Label done;
     b(done); // Monitor register may be overwritten! Runtime has already freed the slot.
 
-    // Exchange worked, do monitor->set_obj(NULL);
+    // Exchange worked, do monitor->set_obj(nullptr);
     align(32, 12);
     bind(free_slot);
     li(R0, 0);
@@ -1701,7 +1701,7 @@ void InterpreterMacroAssembler::record_klass_in_profile_helper(
   }
 
   // In the fall-through case, we found no matching receiver, but we
-  // observed the receiver[start_row] is NULL.
+  // observed the receiver[start_row] is null.
 
   // Fill in the receiver field and increment the count.
   int recvr_offset = in_bytes(VirtualCallData::receiver_offset(start_row));
@@ -2114,7 +2114,7 @@ void InterpreterMacroAssembler::check_and_forward_exception(Register Rscratch1,
   li(Rtmp, 0);
   mr_if_needed(R3, Rexception);
   std(Rtmp, thread_(pending_exception)); // Clear exception in thread
-  if (Interpreter::rethrow_exception_entry() != NULL) {
+  if (Interpreter::rethrow_exception_entry() != nullptr) {
     // Already got entry address.
     load_dispatch_table(Rtmp, (address*)Interpreter::rethrow_exception_entry());
   } else {
diff --git a/src/hotspot/cpu/ppc/interpreterRT_ppc.cpp b/src/hotspot/cpu/ppc/interpreterRT_ppc.cpp
index c22f023df64..e2043db7100 100644
--- a/src/hotspot/cpu/ppc/interpreterRT_ppc.cpp
+++ b/src/hotspot/cpu/ppc/interpreterRT_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2013 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -99,10 +99,10 @@ void InterpreterRuntime::SignatureHandlerGenerator::pass_object() {
   Register r = jni_arg.is_register() ? jni_arg.as_register() : R11_scratch1;
 
   // The handle for a receiver will never be null.
-  bool do_NULL_check = offset() != 0 || is_static();
+  bool do_null_check = offset() != 0 || is_static();
 
   Label do_null;
-  if (do_NULL_check) {
+  if (do_null_check) {
     __ ld(R0, locals_j_arg_at(offset()));
     __ cmpdi(CCR0, R0, 0);
     __ li(r, 0);
diff --git a/src/hotspot/cpu/ppc/javaFrameAnchor_ppc.hpp b/src/hotspot/cpu/ppc/javaFrameAnchor_ppc.hpp
index d78ba49cd64..8b539bc8101 100644
--- a/src/hotspot/cpu/ppc/javaFrameAnchor_ppc.hpp
+++ b/src/hotspot/cpu/ppc/javaFrameAnchor_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2014 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -35,10 +35,10 @@ public:
 
   inline void clear(void) {
     // clearing _last_Java_sp must be first
-    _last_Java_sp = NULL;
+    _last_Java_sp = nullptr;
     // fence?
     OrderAccess::release();
-    _last_Java_pc = NULL;
+    _last_Java_pc = nullptr;
   }
 
   inline void set(intptr_t* sp, address pc) {
@@ -52,10 +52,10 @@ public:
     // We must clear _last_Java_sp before copying the rest of the new data.
     //
     // Hack Alert: Temporary bugfix for 4717480/4721647
-    // To act like previous version (pd_cache_state) don't NULL _last_Java_sp
+    // To act like previous version (pd_cache_state) don't null _last_Java_sp
     // unless the value is changing.
     if (_last_Java_sp != src->_last_Java_sp) {
-      _last_Java_sp = NULL;
+      _last_Java_sp = nullptr;
       OrderAccess::release();
     }
     _last_Java_pc = src->_last_Java_pc;
diff --git a/src/hotspot/cpu/ppc/jniFastGetField_ppc.cpp b/src/hotspot/cpu/ppc/jniFastGetField_ppc.cpp
index 52b39263d0f..819ecaf550e 100644
--- a/src/hotspot/cpu/ppc/jniFastGetField_ppc.cpp
+++ b/src/hotspot/cpu/ppc/jniFastGetField_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2019 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -56,7 +56,7 @@ address JNI_FastGetField::generate_fast_get_int_field0(BasicType type) {
     case T_FLOAT:   name = "jni_fast_GetFloatField";   break;
     case T_DOUBLE:  name = "jni_fast_GetDoubleField";  break;
     default:        ShouldNotReachHere();
-      name = NULL;  // unreachable
+      name = nullptr;  // unreachable
   }
   ResourceMark rm;
   BufferBlob* blob = BufferBlob::create(name, BUFFER_SIZE);
@@ -149,7 +149,7 @@ address JNI_FastGetField::generate_fast_get_int_field0(BasicType type) {
     case T_FLOAT:   slow_case_addr = jni_GetFloatField_addr();   break;
     case T_DOUBLE:  slow_case_addr = jni_GetDoubleField_addr();  break;
     default:        ShouldNotReachHere();
-      slow_case_addr = NULL;  // unreachable
+      slow_case_addr = nullptr;  // unreachable
   }
   __ load_const_optimized(R12, slow_case_addr, R0);
   __ call_c_and_return_to_caller(R12); // tail call
diff --git a/src/hotspot/cpu/ppc/jvmciCodeInstaller_ppc.cpp b/src/hotspot/cpu/ppc/jvmciCodeInstaller_ppc.cpp
index 9121a234977..923a5fd9da9 100644
--- a/src/hotspot/cpu/ppc/jvmciCodeInstaller_ppc.cpp
+++ b/src/hotspot/cpu/ppc/jvmciCodeInstaller_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2023, Oracle and/or its affiliates. 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
@@ -61,7 +61,7 @@ void CodeInstaller::pd_relocate_poll(address pc, jint mark, TRAPS) {
 
 // convert JVMCI register indices (as used in oop maps) to HotSpot registers
 VMReg CodeInstaller::get_hotspot_reg(jint jvmci_reg, TRAPS) {
-  return NULL;
+  return nullptr;
 }
 
 bool CodeInstaller::is_general_purpose_reg(VMReg hotspotRegister) {
diff --git a/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp b/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
index 4bd370605da..a27c208eafe 100644
--- a/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
@@ -274,7 +274,7 @@ bool MacroAssembler::load_const_from_method_toc(Register dst, AddressLiteral& a,
   // pool entries instead of inserting it at the loads; patching of a constant
   // pool entry should be less expensive.
   address const_address = address_constant((address)a.value(), RelocationHolder::none);
-  if (const_address == NULL) { return false; } // allocation failure
+  if (const_address == nullptr) { return false; } // allocation failure
   // Relocate at the pc of the load.
   relocate(a.rspec());
   toc_offset = (int)(const_address - code()->consts()->start());
@@ -361,27 +361,27 @@ void MacroAssembler::patch_const(address a, long x) {
 }
 
 AddressLiteral MacroAssembler::allocate_metadata_address(Metadata* obj) {
-  assert(oop_recorder() != NULL, "this assembler needs a Recorder");
+  assert(oop_recorder() != nullptr, "this assembler needs a Recorder");
   int index = oop_recorder()->allocate_metadata_index(obj);
   RelocationHolder rspec = metadata_Relocation::spec(index);
   return AddressLiteral((address)obj, rspec);
 }
 
 AddressLiteral MacroAssembler::constant_metadata_address(Metadata* obj) {
-  assert(oop_recorder() != NULL, "this assembler needs a Recorder");
+  assert(oop_recorder() != nullptr, "this assembler needs a Recorder");
   int index = oop_recorder()->find_index(obj);
   RelocationHolder rspec = metadata_Relocation::spec(index);
   return AddressLiteral((address)obj, rspec);
 }
 
 AddressLiteral MacroAssembler::allocate_oop_address(jobject obj) {
-  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  assert(oop_recorder() != nullptr, "this assembler needs an OopRecorder");
   int oop_index = oop_recorder()->allocate_oop_index(obj);
   return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
 }
 
 AddressLiteral MacroAssembler::constant_oop_address(jobject obj) {
-  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  assert(oop_recorder() != nullptr, "this assembler needs an OopRecorder");
   int oop_index = oop_recorder()->find_index(obj);
   return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
 }
@@ -466,7 +466,7 @@ address MacroAssembler::get_dest_of_bc_far_at(address instruction_addr) {
   }
   // variant 4 ???
   ShouldNotReachHere();
-  return NULL;
+  return nullptr;
 }
 void MacroAssembler::set_dest_of_bc_far_at(address instruction_addr, address dest) {
 
@@ -706,7 +706,7 @@ address MacroAssembler::get_dest_of_bxx64_patchable_at(address instruction_addr,
                                                                instruction_addr);
   } else {
     ShouldNotReachHere();
-    return NULL;
+    return nullptr;
   }
 }
 
@@ -1086,14 +1086,14 @@ address MacroAssembler::call_c(const FunctionDescriptor* fd, relocInfo::relocTyp
     // this call needs to be relocatable
     if (!ReoptimizeCallSequences
         || (rt != relocInfo::runtime_call_type && rt != relocInfo::none)
-        || fd == NULL   // support code-size estimation
+        || fd == nullptr   // support code-size estimation
         || !fd->is_friend_function()
-        || fd->entry() == NULL) {
+        || fd->entry() == nullptr) {
       // it's not a friend function as defined by class FunctionDescriptor,
       // so do a full call-c here.
       load_const(R11, (address)fd, R0);
 
-      bool has_env = (fd != NULL && fd->env() != NULL);
+      bool has_env = (fd != nullptr && fd->env() != nullptr);
       return branch_to(R11, /*and_link=*/true,
                             /*save toc=*/false,
                             /*restore toc=*/false,
@@ -1150,12 +1150,12 @@ address MacroAssembler::call_c_using_toc(const FunctionDescriptor* fd,
     || !fd->is_friend_function()) {
     // It's not a friend function as defined by class FunctionDescriptor,
     // so do a full call-c here.
-    assert(fd->entry() != NULL, "function must be linked");
+    assert(fd->entry() != nullptr, "function must be linked");
 
     AddressLiteral fd_entry(fd->entry());
     bool success = load_const_from_method_toc(R11, fd_entry, toc, /*fixed_size*/ true);
     mtctr(R11);
-    if (fd->env() == NULL) {
+    if (fd->env() == nullptr) {
       li(R11, 0);
       nop();
     } else {
@@ -1167,7 +1167,7 @@ address MacroAssembler::call_c_using_toc(const FunctionDescriptor* fd,
     success = success && load_const_from_method_toc(R2_TOC, fd_toc, toc, /*fixed_size*/ true);
     bctrl();
     _last_calls_return_pc = pc();
-    if (!success) { return NULL; }
+    if (!success) { return nullptr; }
   } else {
     // It's a friend function, load the entry point and don't care about
     // toc and env. Use an optimizable call instruction, but ensure the
@@ -1306,8 +1306,8 @@ bool MacroAssembler::is_load_from_polling_page(int instruction, void* ucontext,
 
   if (!ucontext) {
     // Set polling address.
-    if (polling_address_ptr != NULL) {
-      *polling_address_ptr = NULL;
+    if (polling_address_ptr != nullptr) {
+      *polling_address_ptr = nullptr;
     }
     return true; // No ucontext given. Can't check value of ra. Assume true.
   }
@@ -1318,12 +1318,12 @@ bool MacroAssembler::is_load_from_polling_page(int instruction, void* ucontext,
   ucontext_t* uc = (ucontext_t*) ucontext;
   // Set polling address.
   address addr = (address)uc->uc_mcontext.regs->gpr[ra] + (ssize_t)ds;
-  if (polling_address_ptr != NULL) {
+  if (polling_address_ptr != nullptr) {
     *polling_address_ptr = addr;
   }
   return SafepointMechanism::is_poll_address(addr);
 #else
-  // Not on Linux, ucontext must be NULL.
+  // Not on Linux, ucontext must be null.
   ShouldNotReachHere();
   return false;
 #endif
@@ -1385,14 +1385,14 @@ address MacroAssembler::get_stack_bang_address(int instruction, void *ucontext)
     int rb = inv_rb_field(instruction);
     address sp = (address)uc->uc_mcontext.regs->gpr[1];
     long rb_val = (long)uc->uc_mcontext.regs->gpr[rb];
-    return ra != 1 || rb_val >= 0 ? NULL         // not a stack bang
+    return ra != 1 || rb_val >= 0 ? nullptr         // not a stack bang
                                   : sp + rb_val; // banged address
   }
-  return NULL; // not a stack bang
+  return nullptr; // not a stack bang
 #else
   // workaround not needed on !LINUX :-)
   ShouldNotCallThis();
-  return NULL;
+  return nullptr;
 #endif
 }
 
@@ -1701,7 +1701,7 @@ void MacroAssembler::cmpxchgd(ConditionRegister flag,
                               Register int_flag_success, Label* failed_ext, bool contention_hint, bool weak) {
   Label retry;
   Label failed_int;
-  Label& failed = (failed_ext != NULL) ? *failed_ext : failed_int;
+  Label& failed = (failed_ext != nullptr) ? *failed_ext : failed_int;
   Label done;
 
   // Save one branch if result is returned via register and result register is different from the other ones.
@@ -1709,7 +1709,7 @@ void MacroAssembler::cmpxchgd(ConditionRegister flag,
   bool preset_result_reg = (int_flag_success!=dest_current_value && int_flag_success!=compare_value.register_or_noreg() &&
                             int_flag_success!=exchange_value && int_flag_success!=addr_base);
   assert(!weak || flag == CCR0, "weak only supported with CCR0");
-  assert(int_flag_success == noreg || failed_ext == NULL, "cannot have both");
+  assert(int_flag_success == noreg || failed_ext == nullptr, "cannot have both");
 
   if (use_result_reg && preset_result_reg) {
     li(int_flag_success, 0); // preset (assume cas failed)
@@ -1816,7 +1816,7 @@ void MacroAssembler::lookup_interface_method(Register recv_klass,
     }
   }
 
-  // for (scan = klass->itable(); scan->interface() != NULL; scan += scan_step) {
+  // for (scan = klass->itable(); scan->interface() != nullptr; scan += scan_step) {
   //   if (scan->interface() == intf) {
   //     result = (klass + scan->offset() + itable_index);
   //   }
@@ -1901,12 +1901,12 @@ void MacroAssembler::check_klass_subtype_fast_path(Register sub_klass,
 
   Label L_fallthrough;
   int label_nulls = 0;
-  if (L_success == NULL)   { L_success   = &L_fallthrough; label_nulls++; }
-  if (L_failure == NULL)   { L_failure   = &L_fallthrough; label_nulls++; }
-  if (L_slow_path == NULL) { L_slow_path = &L_fallthrough; label_nulls++; }
+  if (L_success == nullptr)   { L_success   = &L_fallthrough; label_nulls++; }
+  if (L_failure == nullptr)   { L_failure   = &L_fallthrough; label_nulls++; }
+  if (L_slow_path == nullptr) { L_slow_path = &L_fallthrough; label_nulls++; }
   assert(label_nulls <= 1 ||
          (L_slow_path == &L_fallthrough && label_nulls <= 2 && !need_slow_path),
-         "at most one NULL in the batch, usually");
+         "at most one null in the batch, usually");
 
   // If the pointers are equal, we are done (e.g., String[] elements).
   // This self-check enables sharing of secondary supertype arrays among
@@ -2020,7 +2020,7 @@ void MacroAssembler::check_klass_subtype_slow_path(Register sub_klass,
   bind(hit);
   std(super_klass, target_offset, sub_klass); // save result to cache
   if (result_reg != noreg) { li(result_reg, 0); } // load zero result (indicates a hit)
-  if (L_success != NULL) { b(*L_success); }
+  if (L_success != nullptr) { b(*L_success); }
   else if (result_reg == noreg) { blr(); } // return with CR0.eq if neither label nor result reg provided
 
   bind(fallthru);
@@ -2039,12 +2039,12 @@ void MacroAssembler::check_klass_subtype(Register sub_klass,
 }
 
 void MacroAssembler::clinit_barrier(Register klass, Register thread, Label* L_fast_path, Label* L_slow_path) {
-  assert(L_fast_path != NULL || L_slow_path != NULL, "at least one is required");
+  assert(L_fast_path != nullptr || L_slow_path != nullptr, "at least one is required");
 
   Label L_fallthrough;
-  if (L_fast_path == NULL) {
+  if (L_fast_path == nullptr) {
     L_fast_path = &L_fallthrough;
-  } else if (L_slow_path == NULL) {
+  } else if (L_slow_path == nullptr) {
     L_slow_path = &L_fallthrough;
   }
 
@@ -2133,7 +2133,7 @@ address MacroAssembler::emit_trampoline_stub(int destination_toc_offset,
                                              int insts_call_instruction_offset, Register Rtoc) {
   // Start the stub.
   address stub = start_a_stub(64);
-  if (stub == NULL) { return NULL; } // CodeCache full: bail out
+  if (stub == nullptr) { return nullptr; } // CodeCache full: bail out
 
   // Create a trampoline stub relocation which relates this trampoline stub
   // with the call instruction at insts_call_instruction_offset in the
@@ -2349,7 +2349,7 @@ void MacroAssembler::rtm_abort_ratio_calculation(Register rtm_counters_Reg,
   mulli(tmpReg, tmpReg, RTMAbortRatio);         // allowable range: int16
   cmpd(CCR0, R0, tmpReg);
   blt(CCR0, L_check_always_rtm1); // jump to reload
-  if (method_data != NULL) {
+  if (method_data != nullptr) {
     // Set rtm_state to "no rtm" in MDO.
     // Not using a metadata relocation. Method and Class Loader are kept alive anyway.
     // (See nmethod::metadata_do and CodeBuffer::finalize_oop_references.)
@@ -2370,7 +2370,7 @@ void MacroAssembler::rtm_abort_ratio_calculation(Register rtm_counters_Reg,
     cmpd(CCR0, tmpReg, R0);
   }
   blt(CCR0, L_done);
-  if (method_data != NULL) {
+  if (method_data != nullptr) {
     // Set rtm_state to "always rtm" in MDO.
     // Not using a metadata relocation. See above.
     load_const(R0, (address)method_data + MethodData::rtm_state_offset_in_bytes(), tmpReg);
@@ -2386,14 +2386,14 @@ void MacroAssembler::rtm_profiling(Register abort_status_Reg, Register temp_Reg,
                                    Metadata* method_data,
                                    bool profile_rtm) {
 
-  assert(rtm_counters != NULL, "should not be NULL when profiling RTM");
+  assert(rtm_counters != nullptr, "should not be null when profiling RTM");
   // Update rtm counters based on state at abort.
   // Reads abort_status_Reg, updates flags.
   assert_different_registers(abort_status_Reg, temp_Reg);
   load_const_optimized(temp_Reg, (address)rtm_counters, R0);
   rtm_counters_update(abort_status_Reg, temp_Reg);
   if (profile_rtm) {
-    assert(rtm_counters != NULL, "should not be NULL when profiling RTM");
+    assert(rtm_counters != nullptr, "should not be null when profiling RTM");
     rtm_abort_ratio_calculation(temp_Reg, rtm_counters, method_data);
   }
 }
@@ -2497,7 +2497,7 @@ void MacroAssembler::rtm_stack_locking(ConditionRegister flag,
     if (RTMTotalCountIncrRate > 1) {
       branch_on_random_using_tb(tmp, RTMTotalCountIncrRate, L_noincrement);
     }
-    assert(stack_rtm_counters != NULL, "should not be NULL when profiling RTM");
+    assert(stack_rtm_counters != nullptr, "should not be null when profiling RTM");
     load_const_optimized(tmp, (address)stack_rtm_counters->total_count_addr(), R0);
     //atomic_inc_ptr(tmp, /*temp, will be reloaded*/mark_word); We don't increment atomically
     ldx(mark_word, tmp);
@@ -2564,7 +2564,7 @@ void MacroAssembler::rtm_inflated_locking(ConditionRegister flag,
     if (RTMTotalCountIncrRate > 1) {
       branch_on_random_using_tb(R0, RTMTotalCountIncrRate, L_noincrement);
     }
-    assert(rtm_counters != NULL, "should not be NULL when profiling RTM");
+    assert(rtm_counters != nullptr, "should not be null when profiling RTM");
     load_const(R0, (address)rtm_counters->total_count_addr(), tmpReg);
     //atomic_inc_ptr(R0, tmpReg); We don't increment atomically
     ldx(tmpReg, R0);
@@ -2707,7 +2707,7 @@ void MacroAssembler::compiler_fast_lock_object(ConditionRegister flag, Register
 
   // Handle existing monitor.
   bind(object_has_monitor);
-  // The object's monitor m is unlocked iff m->owner == NULL,
+  // The object's monitor m is unlocked iff m->owner is null,
   // otherwise m->owner may contain a thread or a stack address.
 
 #if INCLUDE_RTM_OPT
@@ -2718,7 +2718,7 @@ void MacroAssembler::compiler_fast_lock_object(ConditionRegister flag, Register
   } else {
 #endif // INCLUDE_RTM_OPT
 
-  // Try to CAS m->owner from NULL to current thread.
+  // Try to CAS m->owner from null to current thread.
   addi(temp, displaced_header, ObjectMonitor::owner_offset_in_bytes()-markWord::monitor_value);
   cmpxchgd(/*flag=*/flag,
            /*current_value=*/current_header,
@@ -2911,7 +2911,7 @@ void MacroAssembler::set_last_Java_frame(Register last_Java_sp, Register last_Ja
                           "last_Java_pc not zeroed before leaving Java");
 
   // When returning from calling out from Java mode the frame anchor's
-  // last_Java_pc will always be set to NULL. It is set here so that
+  // last_Java_pc will always be set to null. It is set here so that
   // if we are doing a call to native (not VM) that we capture the
   // known pc and don't have to rely on the native call having a
   // standard frame linkage where we can find the pc.
@@ -4300,7 +4300,7 @@ void MacroAssembler::verify_oop_addr(RegisterOrConstant offs, Register base, con
 
 // Call a C-function that prints output.
 void MacroAssembler::stop(int type, const char* msg) {
-  bool msg_present = (msg != NULL);
+  bool msg_present = (msg != nullptr);
 
 #ifndef PRODUCT
   block_comment(err_msg("stop(type %d): %s {", type, msg_present ? msg : "null"));
diff --git a/src/hotspot/cpu/ppc/macroAssembler_ppc.hpp b/src/hotspot/cpu/ppc/macroAssembler_ppc.hpp
index 360f7ed9134..732d35b33a2 100644
--- a/src/hotspot/cpu/ppc/macroAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/macroAssembler_ppc.hpp
@@ -427,12 +427,12 @@ class MacroAssembler: public Assembler {
   inline void load_from_polling_page(Register polling_page_address, int offset = 0);
   // Check whether instruction is a read access to the polling page
   // which was emitted by load_from_polling_page(..).
-  static bool is_load_from_polling_page(int instruction, void* ucontext/*may be NULL*/,
-                                        address* polling_address_ptr = NULL);
+  static bool is_load_from_polling_page(int instruction, void* ucontext/*may be nullptr*/,
+                                        address* polling_address_ptr = nullptr);
 
-  // Support for NULL-checks
+  // Support for null-checks
   //
-  // Generates code that causes a NULL OS exception if the content of reg is NULL.
+  // Generates code that causes a null OS exception if the content of reg is null.
   // If the accessed location is M[reg + offset] and the offset is known, provide the
   // offset. No explicit code generation is needed if the offset is within a certain
   // range (0 <= offset <= page_size).
@@ -542,7 +542,7 @@ class MacroAssembler: public Assembler {
   void cmpxchgd(ConditionRegister flag,
                 Register dest_current_value, RegisterOrConstant compare_value, Register exchange_value,
                 Register addr_base, int semantics, bool cmpxchgx_hint = false,
-                Register int_flag_success = noreg, Label* failed = NULL, bool contention_hint = false, bool weak = false);
+                Register int_flag_success = noreg, Label* failed = nullptr, bool contention_hint = false, bool weak = false);
 
   // interface method calling
   void lookup_interface_method(Register recv_klass,
@@ -561,7 +561,7 @@ class MacroAssembler: public Assembler {
   // Test sub_klass against super_klass, with fast and slow paths.
 
   // The fast path produces a tri-state answer: yes / no / maybe-slow.
-  // One of the three labels can be NULL, meaning take the fall-through.
+  // One of the three labels can be null, meaning take the fall-through.
   // If super_check_offset is -1, the value is loaded up from super_klass.
   // No registers are killed, except temp_reg and temp2_reg.
   // If super_check_offset is not -1, temp2_reg is not used and can be noreg.
@@ -571,7 +571,7 @@ class MacroAssembler: public Assembler {
                                      Register temp2_reg,
                                      Label* L_success,
                                      Label* L_failure,
-                                     Label* L_slow_path = NULL, // default fall through
+                                     Label* L_slow_path = nullptr, // default fall through
                                      RegisterOrConstant super_check_offset = RegisterOrConstant(-1));
 
   // The rest of the type check; must be wired to a corresponding fast path.
@@ -583,7 +583,7 @@ class MacroAssembler: public Assembler {
                                      Register super_klass,
                                      Register temp1_reg,
                                      Register temp2_reg,
-                                     Label* L_success = NULL,
+                                     Label* L_success = nullptr,
                                      Register result_reg = noreg);
 
   // Simplified, combined version, good for typical uses.
@@ -596,8 +596,8 @@ class MacroAssembler: public Assembler {
 
   void clinit_barrier(Register klass,
                       Register thread,
-                      Label* L_fast_path = NULL,
-                      Label* L_slow_path = NULL);
+                      Label* L_fast_path = nullptr,
+                      Label* L_slow_path = nullptr);
 
   // Method handle support (JSR 292).
   RegisterOrConstant argument_offset(RegisterOrConstant arg_slot, Register temp_reg, int extra_slot_offset = 0);
@@ -631,7 +631,7 @@ class MacroAssembler: public Assembler {
   void rtm_profiling(Register abort_status_Reg, Register temp_Reg,
                      RTMLockingCounters* rtm_counters, Metadata* method_data, bool profile_rtm);
   void rtm_retry_lock_on_abort(Register retry_count, Register abort_status,
-                               Label& retryLabel, Label* checkRetry = NULL);
+                               Label& retryLabel, Label* checkRetry = nullptr);
   void rtm_retry_lock_on_busy(Register retry_count, Register owner_addr, Label& retryLabel);
   void rtm_stack_locking(ConditionRegister flag, Register obj, Register mark_word, Register tmp,
                          Register retry_on_abort_count,
@@ -647,9 +647,9 @@ class MacroAssembler: public Assembler {
 
   void compiler_fast_lock_object(ConditionRegister flag, Register oop, Register box,
                                  Register tmp1, Register tmp2, Register tmp3,
-                                 RTMLockingCounters* rtm_counters = NULL,
-                                 RTMLockingCounters* stack_rtm_counters = NULL,
-                                 Metadata* method_data = NULL,
+                                 RTMLockingCounters* rtm_counters = nullptr,
+                                 RTMLockingCounters* stack_rtm_counters = nullptr,
+                                 Metadata* method_data = nullptr,
                                  bool use_rtm = false, bool profile_rtm = false);
 
   void compiler_fast_unlock_object(ConditionRegister flag, Register oop, Register box,
@@ -707,7 +707,7 @@ class MacroAssembler: public Assembler {
   inline void access_load_at(BasicType type, DecoratorSet decorators,
                              Register base, RegisterOrConstant ind_or_offs, Register dst,
                              Register tmp1, Register tmp2,
-                             MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = NULL);
+                             MacroAssembler::PreservationLevel preservation_level, Label *L_handle_null = nullptr);
 
  public:
   // Specify tmp1 for better code in certain compressed oops cases. Specify Label to bail out on null oop.
@@ -715,7 +715,7 @@ class MacroAssembler: public Assembler {
   inline void load_heap_oop(Register d, RegisterOrConstant offs, Register s1,
                             Register tmp1, Register tmp2,
                             MacroAssembler::PreservationLevel preservation_level,
-                            DecoratorSet decorators = 0, Label *L_handle_null = NULL);
+                            DecoratorSet decorators = 0, Label *L_handle_null = nullptr);
 
   inline void store_heap_oop(Register d, RegisterOrConstant offs, Register s1,
                              Register tmp1, Register tmp2, Register tmp3,
@@ -927,10 +927,10 @@ class MacroAssembler: public Assembler {
   };
 
   // Prints msg, dumps registers and stops execution.
-  void stop                 (const char* msg = NULL) { stop(stop_stop,               msg); }
-  void untested             (const char* msg = NULL) { stop(stop_untested,           msg); }
-  void unimplemented        (const char* msg = NULL) { stop(stop_unimplemented,      msg); }
-  void should_not_reach_here(const char* msg = NULL) { stop(stop_shouldnotreachhere, msg); }
+  void stop                 (const char* msg = nullptr) { stop(stop_stop,               msg); }
+  void untested             (const char* msg = nullptr) { stop(stop_untested,           msg); }
+  void unimplemented        (const char* msg = nullptr) { stop(stop_unimplemented,      msg); }
+  void should_not_reach_here(const char* msg = nullptr) { stop(stop_shouldnotreachhere, msg); }
 
   void zap_from_to(Register low, int before, Register high, int after, Register val, Register addr) PRODUCT_RETURN;
 };
diff --git a/src/hotspot/cpu/ppc/macroAssembler_ppc.inline.hpp b/src/hotspot/cpu/ppc/macroAssembler_ppc.inline.hpp
index d4a08310dd9..69972bf9eac 100644
--- a/src/hotspot/cpu/ppc/macroAssembler_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/macroAssembler_ppc.inline.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -419,7 +419,7 @@ inline Register MacroAssembler::encode_heap_oop_not_null(Register d, Register sr
 }
 
 inline Register MacroAssembler::encode_heap_oop(Register d, Register src) {
-  if (CompressedOops::base() != NULL) {
+  if (CompressedOops::base() != nullptr) {
     if (VM_Version::has_isel()) {
       cmpdi(CCR0, src, 0);
       Register co = encode_heap_oop_not_null(d, src);
@@ -451,7 +451,7 @@ inline Register MacroAssembler::decode_heap_oop_not_null(Register d, Register sr
     sldi(d, current, CompressedOops::shift());
     current = d;
   }
-  if (CompressedOops::base() != NULL) {
+  if (CompressedOops::base() != nullptr) {
     add_const_optimized(d, current, CompressedOops::base(), R0);
     current = d;
   }
@@ -461,7 +461,7 @@ inline Register MacroAssembler::decode_heap_oop_not_null(Register d, Register sr
 inline void MacroAssembler::decode_heap_oop(Register d) {
   Label isNull;
   bool use_isel = false;
-  if (CompressedOops::base() != NULL) {
+  if (CompressedOops::base() != nullptr) {
     cmpwi(CCR0, d, 0);
     if (VM_Version::has_isel()) {
       use_isel = true;
diff --git a/src/hotspot/cpu/ppc/matcher_ppc.hpp b/src/hotspot/cpu/ppc/matcher_ppc.hpp
index f78cb2d7803..c2486a0bc48 100644
--- a/src/hotspot/cpu/ppc/matcher_ppc.hpp
+++ b/src/hotspot/cpu/ppc/matcher_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2023, Oracle and/or its affiliates. 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
@@ -93,12 +93,12 @@
 
   static bool const_oop_prefer_decode() {
     // Prefer ConN+DecodeN over ConP in simple compressed oops mode.
-    return CompressedOops::base() == NULL;
+    return CompressedOops::base() == nullptr;
   }
 
   static bool const_klass_prefer_decode() {
     // Prefer ConNKlass+DecodeNKlass over ConP in simple compressed klass mode.
-    return CompressedKlassPointers::base() == NULL;
+    return CompressedKlassPointers::base() == nullptr;
   }
 
   // Is it better to copy float constants, or load them directly from memory?
diff --git a/src/hotspot/cpu/ppc/methodHandles_ppc.cpp b/src/hotspot/cpu/ppc/methodHandles_ppc.cpp
index 4aea1517023..eee918e7bb0 100644
--- a/src/hotspot/cpu/ppc/methodHandles_ppc.cpp
+++ b/src/hotspot/cpu/ppc/methodHandles_ppc.cpp
@@ -158,7 +158,7 @@ void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, Register meth
   __ bctr();
 
   __ bind(L_no_such_method);
-  assert(StubRoutines::throw_AbstractMethodError_entry() != NULL, "not yet generated!");
+  assert(StubRoutines::throw_AbstractMethodError_entry() != nullptr, "not yet generated!");
   __ load_const_optimized(target, StubRoutines::throw_AbstractMethodError_entry());
   __ mtctr(target);
   __ bctr();
@@ -224,14 +224,14 @@ address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler*
     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
     // They all allow an appendix argument.
     __ stop("Should not reach here");           // empty stubs make SG sick
-    return NULL;
+    return nullptr;
   }
 
   // No need in interpreter entry for linkToNative for now.
   // Interpreter calls compiled entry through i2c.
   if (iid == vmIntrinsics::_linkToNative) {
     __ stop("Should not reach here");           // empty stubs make SG sick
-    return NULL;
+    return nullptr;
   }
 
   Register R15_argbase   = R15_esp; // parameter (preserved)
@@ -495,8 +495,8 @@ void trace_method_handle_stub(const char* adaptername,
                               intptr_t* entry_sp,
                               intptr_t* saved_regs) {
 
-  bool has_mh = (strstr(adaptername, "/static") == NULL &&
-                 strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH
+  bool has_mh = (strstr(adaptername, "/static") == nullptr &&
+                 strstr(adaptername, "linkTo") == nullptr);    // static linkers don't have MH
   const char* mh_reg_name = has_mh ? "R23_method_handle" : "G23";
   log_info(methodhandles)("MH %s %s=" INTPTR_FORMAT " sp=" INTPTR_FORMAT,
                 adaptername, mh_reg_name, p2i(mh), p2i(entry_sp));
diff --git a/src/hotspot/cpu/ppc/nativeInst_ppc.cpp b/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
index 6b0e96956e9..f60f3f147ae 100644
--- a/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
+++ b/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2020 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -45,7 +45,7 @@
 bool NativeInstruction::is_sigill_not_entrant_at(address addr) {
   if (!Assembler::is_illtrap(addr)) return false;
   CodeBlob* cb = CodeCache::find_blob(addr);
-  if (cb == NULL || !cb->is_nmethod()) return false;
+  if (cb == nullptr || !cb->is_nmethod()) return false;
   nmethod *nm = (nmethod *)cb;
   // This method is not_entrant iff the illtrap instruction is
   // located at the verified entry point.
@@ -133,12 +133,12 @@ address NativeCall::get_trampoline() {
   address call_addr = addr_at(0);
 
   CodeBlob *code = CodeCache::find_blob(call_addr);
-  assert(code != NULL, "Could not find the containing code blob");
+  assert(code != nullptr, "Could not find the containing code blob");
 
   // There are no relocations available when the code gets relocated
   // because of CodeBuffer expansion.
   if (code->relocation_size() == 0)
-    return NULL;
+    return nullptr;
 
   address bl_destination = Assembler::bxx_destination(call_addr);
   if (code->contains(bl_destination) &&
@@ -178,7 +178,7 @@ void NativeFarCall::verify() {
 address NativeMovConstReg::next_instruction_address() const {
 #ifdef ASSERT
   CodeBlob* nm = CodeCache::find_blob(instruction_address());
-  assert(nm != NULL, "Could not find code blob");
+  assert(nm != nullptr, "Could not find code blob");
   assert(!MacroAssembler::is_set_narrow_oop(addr_at(0), nm->content_begin()), "Should not patch narrow oop here");
 #endif
 
@@ -197,7 +197,7 @@ intptr_t NativeMovConstReg::data() const {
   }
 
   CodeBlob* cb = CodeCache::find_blob(addr);
-  assert(cb != NULL, "Could not find code blob");
+  assert(cb != nullptr, "Could not find code blob");
   if (MacroAssembler::is_set_narrow_oop(addr, cb->content_begin())) {
     narrowOop no = MacroAssembler::get_narrow_oop(addr, cb->content_begin());
     // We can reach here during GC with 'no' pointing to new object location
@@ -216,17 +216,17 @@ intptr_t NativeMovConstReg::data() const {
 
 address NativeMovConstReg::set_data_plain(intptr_t data, CodeBlob *cb) {
   address addr         = instruction_address();
-  address next_address = NULL;
+  address next_address = nullptr;
   if (!cb) cb = CodeCache::find_blob(addr);
 
-  if (cb != NULL && MacroAssembler::is_load_const_from_method_toc_at(addr)) {
+  if (cb != nullptr && MacroAssembler::is_load_const_from_method_toc_at(addr)) {
     // A load from the method's TOC (ctable).
     assert(cb->is_nmethod(), "must be nmethod");
     const address ctable = cb->content_begin();
     const int toc_offset = MacroAssembler::get_offset_of_load_const_from_method_toc_at(addr);
     *(intptr_t *)(ctable + toc_offset) = data;
     next_address = addr + BytesPerInstWord;
-  } else if (cb != NULL &&
+  } else if (cb != nullptr &&
              MacroAssembler::is_calculate_address_from_global_toc_at(addr, cb->content_begin())) {
     // A calculation relative to the global TOC.
     if (MacroAssembler::get_address_of_calculate_address_from_global_toc_at(addr, cb->content_begin()) !=
@@ -235,7 +235,7 @@ address NativeMovConstReg::set_data_plain(intptr_t data, CodeBlob *cb) {
       const address inst1_addr =
         MacroAssembler::patch_calculate_address_from_global_toc_at(inst2_addr, cb->content_begin(),
                                                                    (address)data);
-      assert(inst1_addr != NULL && inst1_addr < inst2_addr, "first instruction must be found");
+      assert(inst1_addr != nullptr && inst1_addr < inst2_addr, "first instruction must be found");
       const int range = inst2_addr - inst1_addr + BytesPerInstWord;
       ICache::ppc64_flush_icache_bytes(inst1_addr, range);
     }
@@ -272,12 +272,12 @@ void NativeMovConstReg::set_data(intptr_t data) {
   // Also store the value into an oop_Relocation cell, if any.
   if (cb && cb->is_nmethod()) {
     RelocIterator iter((nmethod *) cb, instruction_address(), next_address);
-    oop* oop_addr = NULL;
-    Metadata** metadata_addr = NULL;
+    oop* oop_addr = nullptr;
+    Metadata** metadata_addr = nullptr;
     while (iter.next()) {
       if (iter.type() == relocInfo::oop_type) {
         oop_Relocation *r = iter.oop_reloc();
-        if (oop_addr == NULL) {
+        if (oop_addr == nullptr) {
           oop_addr = r->oop_addr();
           *oop_addr = cast_to_oop(data);
         } else {
@@ -286,7 +286,7 @@ void NativeMovConstReg::set_data(intptr_t data) {
       }
       if (iter.type() == relocInfo::metadata_type) {
         metadata_Relocation *r = iter.metadata_reloc();
-        if (metadata_addr == NULL) {
+        if (metadata_addr == nullptr) {
           metadata_addr = r->metadata_addr();
           *metadata_addr = (Metadata*)data;
         } else {
@@ -297,16 +297,16 @@ void NativeMovConstReg::set_data(intptr_t data) {
   }
 }
 
-void NativeMovConstReg::set_narrow_oop(narrowOop data, CodeBlob *code /* = NULL */) {
+void NativeMovConstReg::set_narrow_oop(narrowOop data, CodeBlob *code /* = nullptr */) {
   address   inst2_addr = addr_at(0);
   CodeBlob* cb = (code) ? code : CodeCache::find_blob(instruction_address());
-  assert(cb != NULL, "Could not find code blob");
+  assert(cb != nullptr, "Could not find code blob");
   if (MacroAssembler::get_narrow_oop(inst2_addr, cb->content_begin()) == data) {
     return;
   }
   const address inst1_addr =
     MacroAssembler::patch_set_narrow_oop(inst2_addr, cb->content_begin(), data);
-  assert(inst1_addr != NULL && inst1_addr < inst2_addr, "first instruction must be found");
+  assert(inst1_addr != nullptr && inst1_addr < inst2_addr, "first instruction must be found");
   const int range = inst2_addr - inst1_addr + BytesPerInstWord;
   ICache::ppc64_flush_icache_bytes(inst1_addr, range);
 }
@@ -319,8 +319,8 @@ void NativeMovConstReg::verify() {
   if (! MacroAssembler::is_load_const_at(addr) &&
       ! MacroAssembler::is_load_const_from_method_toc_at(addr)) {
     CodeBlob* cb = CodeCache::find_blob(addr);
-    if (! (cb != NULL && MacroAssembler::is_calculate_address_from_global_toc_at(addr, cb->content_begin())) &&
-        ! (cb != NULL && MacroAssembler::is_set_narrow_oop(addr, cb->content_begin())) &&
+    if (! (cb != nullptr && MacroAssembler::is_calculate_address_from_global_toc_at(addr, cb->content_begin())) &&
+        ! (cb != nullptr && MacroAssembler::is_set_narrow_oop(addr, cb->content_begin())) &&
         ! MacroAssembler::is_bl(*((int*) addr))) {
       tty->print_cr("not a NativeMovConstReg at " PTR_FORMAT, p2i(addr));
       // TODO: PPC port: Disassembler::decode(addr, 20, 20, tty);
@@ -407,7 +407,7 @@ address NativeCallTrampolineStub::encoded_destination_addr() const {
 
 address NativeCallTrampolineStub::destination(nmethod *nm) const {
   CodeBlob* cb = nm ? nm : CodeCache::find_blob(addr_at(0));
-  assert(cb != NULL, "Could not find code blob");
+  assert(cb != nullptr, "Could not find code blob");
   address ctable = cb->content_begin();
 
   return *(address*)(ctable + destination_toc_offset());
@@ -419,7 +419,7 @@ int NativeCallTrampolineStub::destination_toc_offset() const {
 
 void NativeCallTrampolineStub::set_destination(address new_destination) {
   CodeBlob* cb = CodeCache::find_blob(addr_at(0));
-  assert(cb != NULL, "Could not find code blob");
+  assert(cb != nullptr, "Could not find code blob");
   address ctable = cb->content_begin();
 
   *(address*)(ctable + destination_toc_offset()) = new_destination;
@@ -439,7 +439,7 @@ void NativeDeoptInstruction::verify() {
 bool NativeDeoptInstruction::is_deopt_at(address code_pos) {
   if (!Assembler::is_illtrap(code_pos)) return false;
   CodeBlob* cb = CodeCache::find_blob(code_pos);
-  if (cb == NULL || !cb->is_compiled()) return false;
+  if (cb == nullptr || !cb->is_compiled()) return false;
   nmethod *nm = (nmethod *)cb;
   // see NativeInstruction::is_sigill_not_entrant_at()
   return nm->verified_entry_point() != code_pos;
diff --git a/src/hotspot/cpu/ppc/nativeInst_ppc.hpp b/src/hotspot/cpu/ppc/nativeInst_ppc.hpp
index 507de109d60..378f4ea928a 100644
--- a/src/hotspot/cpu/ppc/nativeInst_ppc.hpp
+++ b/src/hotspot/cpu/ppc/nativeInst_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -91,7 +91,7 @@ class NativeInstruction {
       return MacroAssembler::is_tdi(long_at(0), Assembler::traptoGreaterThanUnsigned | Assembler::traptoEqual,
                                     -1, encoding);
     }
-    return MacroAssembler::is_load_from_polling_page(long_at(0), NULL);
+    return MacroAssembler::is_load_from_polling_page(long_at(0), nullptr);
   }
 
   bool is_safepoint_poll_return() {
@@ -177,7 +177,7 @@ inline NativeCall* nativeCall_at(address instr) {
 }
 
 inline NativeCall* nativeCall_before(address return_address) {
-  NativeCall* call = NULL;
+  NativeCall* call = nullptr;
   if (MacroAssembler::is_bl(*(int*)(return_address - 4)))
     call = (NativeCall*)(return_address - 4);
   call->verify();
@@ -260,7 +260,7 @@ class NativeMovConstReg: public NativeInstruction {
   void set_data(intptr_t x);
 
   // Patch narrow oop constants.
-  void set_narrow_oop(narrowOop data, CodeBlob *code = NULL);
+  void set_narrow_oop(narrowOop data, CodeBlob *code = nullptr);
 
   void verify() NOT_DEBUG_RETURN;
 };
@@ -307,7 +307,7 @@ class NativeJump: public NativeInstruction {
       return (address)((NativeMovConstReg *)this)->data();
     } else {
       ShouldNotReachHere();
-      return NULL;
+      return nullptr;
     }
   }
 
@@ -377,7 +377,7 @@ class NativeCallTrampolineStub : public NativeInstruction {
 
  public:
 
-  address destination(nmethod *nm = NULL) const;
+  address destination(nmethod *nm = nullptr) const;
   int destination_toc_offset() const;
 
   void set_destination(address new_destination);
@@ -518,7 +518,7 @@ inline NativePostCallNop* nativePostCallNop_at(address address) {
   if (nop->check()) {
     return nop;
   }
-  return NULL;
+  return nullptr;
 }
 
 class NativeDeoptInstruction: public NativeInstruction {
diff --git a/src/hotspot/cpu/ppc/registerMap_ppc.hpp b/src/hotspot/cpu/ppc/registerMap_ppc.hpp
index cbbed577d5f..01eb642107c 100644
--- a/src/hotspot/cpu/ppc/registerMap_ppc.hpp
+++ b/src/hotspot/cpu/ppc/registerMap_ppc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2013 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -32,8 +32,8 @@
  private:
   // This is the hook for finding a register in an "well-known" location,
   // such as a register block of a predetermined format.
-  // Since there is none, we just return NULL.
-  address pd_location(VMReg reg) const { return NULL; }
+  // Since there is none, we just return null.
+  address pd_location(VMReg reg) const { return nullptr; }
 
   address pd_location(VMReg base_reg, int slot_idx) const {
     return location(base_reg->next(slot_idx), nullptr);
diff --git a/src/hotspot/cpu/ppc/relocInfo_ppc.cpp b/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
index a3a63c6283f..39e50465231 100644
--- a/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
+++ b/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -53,7 +53,7 @@ address Relocation::pd_call_destination(address orig_addr) {
   intptr_t adj = 0;
   address inst_loc = addr();
 
-  if (orig_addr != NULL) {
+  if (orig_addr != nullptr) {
     // We just moved this call instruction from orig_addr to addr().
     // This means its target will appear to have grown by addr() - orig_addr.
     adj = -(inst_loc - orig_addr);
@@ -69,7 +69,7 @@ address Relocation::pd_call_destination(address orig_addr) {
     return branch->branch_destination();
   } else {
     orig_addr = nativeCall_at(inst_loc)->get_trampoline();
-    if (orig_addr == NULL) {
+    if (orig_addr == nullptr) {
       return (address) -1;
     } else {
       return ((NativeCallTrampolineStub*)orig_addr)->destination();
diff --git a/src/hotspot/cpu/ppc/runtime_ppc.cpp b/src/hotspot/cpu/ppc/runtime_ppc.cpp
index 70b872fd7d7..7f2d3e627eb 100644
--- a/src/hotspot/cpu/ppc/runtime_ppc.cpp
+++ b/src/hotspot/cpu/ppc/runtime_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -108,7 +108,7 @@ void OptoRuntime::generate_exception_blob() {
   address calls_return_pc = __ last_calls_return_pc();
 # ifdef ASSERT
   __ cmpdi(CCR0, R3_RET, 0);
-  __ asm_assert_ne("handle_exception_C must not return NULL");
+  __ asm_assert_ne("handle_exception_C must not return null");
 # endif
 
   // Set an oopmap for the call site. This oopmap will only be used if we
diff --git a/src/hotspot/cpu/ppc/sharedRuntime_ppc.cpp b/src/hotspot/cpu/ppc/sharedRuntime_ppc.cpp
index 4f6ae3859ad..71842f33dfd 100644
--- a/src/hotspot/cpu/ppc/sharedRuntime_ppc.cpp
+++ b/src/hotspot/cpu/ppc/sharedRuntime_ppc.cpp
@@ -97,11 +97,11 @@ class RegisterSaver {
                          Register r_temp,
                          int frame_size,
                          int total_args,
-                         const VMRegPair *regs, const VMRegPair *regs2 = NULL);
+                         const VMRegPair *regs, const VMRegPair *regs2 = nullptr);
   static void restore_argument_registers_and_pop_frame(MacroAssembler*masm,
                          int frame_size,
                          int total_args,
-                         const VMRegPair *regs, const VMRegPair *regs2 = NULL);
+                         const VMRegPair *regs, const VMRegPair *regs2 = nullptr);
 
   // During deoptimization only the result registers need to be restored
   // all the other values have already been extracted.
@@ -279,7 +279,7 @@ OopMap* RegisterSaver::push_frame_reg_args_and_save_live_registers(MacroAssemble
   const int register_save_offset = frame_size_in_bytes - register_save_size;
 
   // OopMap frame size is in c2 stack slots (sizeof(jint)) not bytes or words.
-  OopMap* map = generate_oop_map ? new OopMap(frame_size_in_slots, 0) : NULL;
+  OopMap* map = generate_oop_map ? new OopMap(frame_size_in_slots, 0) : nullptr;
 
   BLOCK_COMMENT("push_frame_reg_args_and_save_live_registers {");
 
@@ -472,7 +472,7 @@ void RegisterSaver::push_frame_and_save_argument_registers(MacroAssembler* masm,
       st_off -= wordSize;
     }
   }
-  if (regs2 != NULL) {
+  if (regs2 != nullptr) {
     for (int i = 0; i < total_args; i++) {
       VMReg r_1 = regs2[i].first();
       VMReg r_2 = regs2[i].second();
@@ -510,7 +510,7 @@ void RegisterSaver::restore_argument_registers_and_pop_frame(MacroAssembler*masm
       st_off -= wordSize;
     }
   }
-  if (regs2 != NULL)
+  if (regs2 != nullptr)
     for (int i = 0; i < total_args; i++) {
       VMReg r_1 = regs2[i].first();
       VMReg r_2 = regs2[i].second();
@@ -803,11 +803,11 @@ int SharedRuntime::c_calling_convention(const BasicType *sig_bt,
          "passing C arguments in wrong stack slots");
 #endif
   // We fill-out regs AND regs2 if an argument must be passed in a
-  // register AND in a stack slot. If regs2 is NULL in such a
+  // register AND in a stack slot. If regs2 is null in such a
   // situation, we bail-out with a fatal error.
   for (int i = 0; i < total_args_passed; ++i, ++arg) {
     // Initialize regs2 to BAD.
-    if (regs2 != NULL) regs2[i].set_bad();
+    if (regs2 != nullptr) regs2[i].set_bad();
 
     switch(sig_bt[i]) {
 
@@ -871,7 +871,7 @@ int SharedRuntime::c_calling_convention(const BasicType *sig_bt,
         // convention, too.
         if (arg >= Argument::n_regs_not_on_stack_c) {
           // ... and on the stack.
-          guarantee(regs2 != NULL, "must pass float in register and stack slot");
+          guarantee(regs2 != nullptr, "must pass float in register and stack slot");
           VMReg reg2 = VMRegImpl::stack2reg(stk + FLOAT_WORD_OFFSET_IN_SLOT);
           regs2[i].set1(reg2);
           stk += inc_stk_for_intfloat;
@@ -898,7 +898,7 @@ int SharedRuntime::c_calling_convention(const BasicType *sig_bt,
         // convention, too.
         if (arg >= Argument::n_regs_not_on_stack_c) {
           // ... and on the stack.
-          guarantee(regs2 != NULL, "must pass float in register and stack slot");
+          guarantee(regs2 != nullptr, "must pass float in register and stack slot");
           VMReg reg2 = VMRegImpl::stack2reg(stk);
           regs2[i].set2(reg2);
           stk += inc_stk_for_longdouble;
@@ -968,7 +968,7 @@ static address gen_c2i_adapter(MacroAssembler *masm,
   __ beq(CCR0, call_interpreter);
 
 
-  // Patch caller's callsite, method_(code) was not NULL which means that
+  // Patch caller's callsite, method_(code) was not null which means that
   // compiled code exists.
   __ mflr(return_pc);
   __ std(return_pc, _abi0(lr), R1_SP);
@@ -1236,7 +1236,7 @@ AdapterHandlerEntry* SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm
 
   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()),
          "klass offset should reach into any page");
-  // Check for NULL argument if we don't have implicit null checks.
+  // Check for null argument if we don't have implicit null checks.
   if (!ImplicitNullChecks || !os::zero_page_read_protected()) {
     if (TrapBasedNullChecks) {
       __ trap_null_check(R3_ARG1);
@@ -1250,7 +1250,7 @@ AdapterHandlerEntry* SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm
       __ BIND(valid);
     }
   }
-  // Assume argument is not NULL, load klass from receiver.
+  // Assume argument is not null, load klass from receiver.
   __ load_klass(receiver_klass, R3_ARG1);
 
   __ ld(ic_klass, CompiledICHolder::holder_klass_offset(), ic);
@@ -1286,7 +1286,7 @@ AdapterHandlerEntry* SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm
   c2i_entry = __ pc();
 
   // Class initialization barrier for static methods
-  address c2i_no_clinit_check_entry = NULL;
+  address c2i_no_clinit_check_entry = nullptr;
   if (VM_Version::supports_fast_class_init_checks()) {
     Label L_skip_barrier;
 
@@ -1343,7 +1343,7 @@ static void object_move(MacroAssembler* masm,
     __ ld(  r_temp_2, reg2offset(src.first()), r_caller_sp);
     __ cmpdi(CCR0, r_temp_2, 0);
     __ bne(CCR0, skip);
-    // Use a NULL handle if oop is NULL.
+    // Use a null handle if oop is null.
     __ li(r_handle, 0);
     __ bind(skip);
 
@@ -1373,7 +1373,7 @@ static void object_move(MacroAssembler* masm,
 
     __ cmpdi(CCR0, r_oop, 0);
     __ bne(CCR0, skip);
-    // Use a NULL handle if oop is NULL.
+    // Use a null handle if oop is null.
     __ li(r_handle, 0);
     __ bind(skip);
 
@@ -2114,11 +2114,11 @@ nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,
                                        stack_slots / VMRegImpl::slots_per_word,
                                        in_ByteSize(-1),
                                        in_ByteSize(-1),
-                                       (OopMapSet*)NULL);
+                                       (OopMapSet*)nullptr);
   }
 
   address native_func = method->native_function();
-  assert(native_func != NULL, "must have function");
+  assert(native_func != nullptr, "must have function");
 
   // First, create signature for outgoing C call
   // --------------------------------------------------------------------------
@@ -2141,7 +2141,7 @@ nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,
   BasicType *out_sig_bt = NEW_RESOURCE_ARRAY(BasicType, total_c_args);
   VMRegPair *out_regs   = NEW_RESOURCE_ARRAY(VMRegPair, total_c_args);
   VMRegPair *out_regs2  = NEW_RESOURCE_ARRAY(VMRegPair, total_c_args);
-  BasicType* in_elem_bt = NULL;
+  BasicType* in_elem_bt = nullptr;
 
   // Create the signature for the C call:
   //   1) add the JNIEnv*
@@ -2946,7 +2946,7 @@ void SharedRuntime::generate_deopt_blob() {
   InterpreterMacroAssembler* masm = new InterpreterMacroAssembler(&buffer);
   Label exec_mode_initialized;
   int frame_size_in_words;
-  OopMap* map = NULL;
+  OopMap* map = nullptr;
   OopMapSet *oop_maps = new OopMapSet();
 
   // size of ABI112 plus spill slots for R3_RET and F1_RET.
@@ -2988,7 +2988,7 @@ void SharedRuntime::generate_deopt_blob() {
                                                                    /*generate_oop_map=*/ true,
                                                                    return_pc_adjustment_no_exception,
                                                                    RegisterSaver::return_pc_is_lr);
-  assert(map != NULL, "OopMap must have been created");
+  assert(map != nullptr, "OopMap must have been created");
 
   __ li(exec_mode_reg, Deoptimization::Unpack_deopt);
   // Save exec mode for unpack_frames.
@@ -3298,7 +3298,7 @@ void SharedRuntime::generate_uncommon_trap_blob() {
 
 // Generate a special Compile2Runtime blob that saves all registers, and setup oopmap.
 SafepointBlob* SharedRuntime::generate_handler_blob(address call_ptr, int poll_type) {
-  assert(StubRoutines::forward_exception_entry() != NULL,
+  assert(StubRoutines::forward_exception_entry() != nullptr,
          "must be generated before");
 
   ResourceMark rm;
@@ -3428,7 +3428,7 @@ RuntimeStub* SharedRuntime::generate_resolve_blob(address destination, const cha
   int frame_size_in_bytes;
 
   OopMapSet *oop_maps = new OopMapSet();
-  OopMap* map = NULL;
+  OopMap* map = nullptr;
 
   address start = __ pc();
 
diff --git a/src/hotspot/cpu/ppc/smallRegisterMap_ppc.inline.hpp b/src/hotspot/cpu/ppc/smallRegisterMap_ppc.inline.hpp
index 8e78e12454b..8c96f51fd88 100644
--- a/src/hotspot/cpu/ppc/smallRegisterMap_ppc.inline.hpp
+++ b/src/hotspot/cpu/ppc/smallRegisterMap_ppc.inline.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2023, Oracle and/or its affiliates. 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
@@ -83,7 +83,7 @@ public:
   bool should_skip_missing() const  { return false; }
   VMReg find_register_spilled_here(void* p, intptr_t* sp) {
     Unimplemented();
-    return NULL;
+    return nullptr;
   }
   void print() const { print_on(tty); }
   void print_on(outputStream* st) const { st->print_cr("Small register map"); }
diff --git a/src/hotspot/cpu/ppc/stubGenerator_ppc.cpp b/src/hotspot/cpu/ppc/stubGenerator_ppc.cpp
index 8a8a8faf767..170c77890b3 100644
--- a/src/hotspot/cpu/ppc/stubGenerator_ppc.cpp
+++ b/src/hotspot/cpu/ppc/stubGenerator_ppc.cpp
@@ -412,7 +412,7 @@ class StubGenerator: public StubCodeGenerator {
     __ stw(exception_line, in_bytes(JavaThread::exception_line_offset()), R16_thread);
 
     // complete return to VM
-    assert(StubRoutines::_call_stub_return_address != NULL, "must have been generated before");
+    assert(StubRoutines::_call_stub_return_address != nullptr, "must have been generated before");
 
     __ mtlr(R4_ARG2);
     // continue in call stub
@@ -2134,7 +2134,7 @@ class StubGenerator: public StubCodeGenerator {
 
     Label L_miss;
 
-    __ check_klass_subtype_fast_path(sub_klass, super_klass, temp, R0, &L_success, &L_miss, NULL,
+    __ check_klass_subtype_fast_path(sub_klass, super_klass, temp, R0, &L_success, &L_miss, nullptr,
                                      super_check_offset);
     __ check_klass_subtype_slow_path(sub_klass, super_klass, temp, R0, &L_success);
 
@@ -2412,15 +2412,15 @@ class StubGenerator: public StubCodeGenerator {
     // (2) src_pos must not be negative.
     // (3) dst_pos must not be negative.
     // (4) length  must not be negative.
-    // (5) src klass and dst klass should be the same and not NULL.
+    // (5) src klass and dst klass should be the same and not null.
     // (6) src and dst should be arrays.
     // (7) src_pos + length must not exceed length of src.
     // (8) dst_pos + length must not exceed length of dst.
     BLOCK_COMMENT("arraycopy initial argument checks");
 
-    __ cmpdi(CCR1, src, 0);      // if (src == NULL) return -1;
+    __ cmpdi(CCR1, src, 0);      // if (src == nullptr) return -1;
     __ extsw_(src_pos, src_pos); // if (src_pos < 0) return -1;
-    __ cmpdi(CCR5, dst, 0);      // if (dst == NULL) return -1;
+    __ cmpdi(CCR5, dst, 0);      // if (dst == nullptr) return -1;
     __ cror(CCR1, Assembler::equal, CCR0, Assembler::less);
     __ extsw_(dst_pos, dst_pos); // if (src_pos < 0) return -1;
     __ cror(CCR5, Assembler::equal, CCR0, Assembler::less);
@@ -4713,7 +4713,7 @@ class StubGenerator: public StubCodeGenerator {
 
     // nmethod entry barriers for concurrent class unloading
     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
-    if (bs_nm != NULL) {
+    if (bs_nm != nullptr) {
       StubRoutines::ppc::_nmethod_entry_barrier            = generate_nmethod_entry_barrier();
     }
 
diff --git a/src/hotspot/cpu/ppc/stubRoutines_ppc_64.cpp b/src/hotspot/cpu/ppc/stubRoutines_ppc_64.cpp
index c49a4ede6a4..f2dc2144567 100644
--- a/src/hotspot/cpu/ppc/stubRoutines_ppc_64.cpp
+++ b/src/hotspot/cpu/ppc/stubRoutines_ppc_64.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2019 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -86,7 +86,7 @@ address StubRoutines::ppc::generate_crc_constants(juint reverse_poly) {
 
   const int size = use_vector ? CRC32_TABLE_SIZE + vector_size : (4 BIG_ENDIAN_ONLY(+1)) * CRC32_TABLE_SIZE;
   const address consts = (address)os::malloc(size, mtInternal);
-  if (consts == NULL) {
+  if (consts == nullptr) {
     vm_exit_out_of_memory(size, OOM_MALLOC_ERROR, "CRC constants: no enough space");
   }
   juint* ptr = (juint*)consts;
diff --git a/src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp b/src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp
index 8511bc9efdb..42c179b05d1 100644
--- a/src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp
+++ b/src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp
@@ -523,7 +523,7 @@ address TemplateInterpreterGenerator::generate_Reference_get_entry(void) {
   // If the receiver is null then it is OK to jump to the slow path.
   __ ld(R3_RET, Interpreter::stackElementSize, R15_esp); // get receiver
 
-  // Check if receiver == NULL and go the slow path.
+  // Check if receiver == nullptr and go the slow path.
   __ cmpdi(CCR0, R3_RET, 0);
   __ beq(CCR0, slow_path);
 
@@ -693,7 +693,7 @@ address TemplateInterpreterGenerator::generate_deopt_entry_for(TosState state, i
   __ check_and_forward_exception(R11_scratch1, R12_scratch2);
 
   // Start executing bytecodes.
-  if (continuation == NULL) {
+  if (continuation == nullptr) {
     __ dispatch_next(state, step);
   } else {
     __ jump_to_entry(continuation, R11_scratch1);
@@ -766,9 +766,9 @@ void TemplateInterpreterGenerator::generate_counter_overflow(Label& continue_ent
   // Generate code to initiate compilation on the counter overflow.
 
   // InterpreterRuntime::frequency_counter_overflow takes one arguments,
-  // which indicates if the counter overflow occurs at a backwards branch (NULL bcp)
+  // which indicates if the counter overflow occurs at a backwards branch (null bcp)
   // We pass zero in.
-  // The call returns the address of the verified entry point for the method or NULL
+  // The call returns the address of the verified entry point for the method or null
   // if the compilation did not complete (either went background or bailed out).
   //
   // Unlike the C++ interpreter above: Check exceptions!
@@ -778,7 +778,7 @@ void TemplateInterpreterGenerator::generate_counter_overflow(Label& continue_ent
   __ li(R4_ARG2, 0);
   __ call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::frequency_counter_overflow), R4_ARG2, true);
 
-  // Returns verified_entry_point or NULL.
+  // Returns verified_entry_point or null.
   // We ignore it in any case.
   __ b(continue_entry);
 }
@@ -801,7 +801,7 @@ void TemplateInterpreterGenerator::generate_stack_overflow_check(Register Rmem_f
   __ bgt(CCR0/*is_stack_overflow*/, done);
 
   // The stack overflows. Load target address of the runtime stub and call it.
-  assert(StubRoutines::throw_StackOverflowError_entry() != NULL, "generated in wrong order");
+  assert(StubRoutines::throw_StackOverflowError_entry() != nullptr, "generated in wrong order");
   __ load_const_optimized(Rscratch1, (StubRoutines::throw_StackOverflowError_entry()), R0);
   __ mtctr(Rscratch1);
   // Restore caller_sp (c2i adapter may exist, but no shrinking of interpreted caller frame).
@@ -1074,7 +1074,7 @@ address TemplateInterpreterGenerator::generate_math_entry(AbstractInterpreter::M
 
   // Decide what to do: Use same platform specific instructions and runtime calls as compilers.
   bool use_instruction = false;
-  address runtime_entry = NULL;
+  address runtime_entry = nullptr;
   int num_args = 1;
   bool double_precision = true;
 
@@ -1103,7 +1103,7 @@ address TemplateInterpreterGenerator::generate_math_entry(AbstractInterpreter::M
   }
 
   // Use normal entry if neither instruction nor runtime call is used.
-  if (!use_instruction && runtime_entry == NULL) return NULL;
+  if (!use_instruction && runtime_entry == nullptr) return nullptr;
 
   address entry = __ pc();
 
@@ -2067,7 +2067,7 @@ void TemplateInterpreterGenerator::generate_throw_exception() {
     __ bne(CCR0, L_done);
 
     // The member name argument must be restored if _invokestatic is re-executed after a PopFrame call.
-    // Detect such a case in the InterpreterRuntime function and return the member name argument, or NULL.
+    // Detect such a case in the InterpreterRuntime function and return the member name argument, or null.
     __ ld(R4_ARG2, 0, R18_locals);
     __ call_VM(R4_ARG2, CAST_FROM_FN_PTR(address, InterpreterRuntime::member_name_arg_or_null), R4_ARG2, R19_method, R14_bcp);
 
@@ -2197,7 +2197,7 @@ address TemplateInterpreterGenerator::generate_trace_code(TosState state) {
   //__ flush_bundle();
   address entry = __ pc();
 
-  const char *bname = NULL;
+  const char *bname = nullptr;
   uint tsize = 0;
   switch(state) {
   case ftos:
@@ -2319,7 +2319,7 @@ void TemplateInterpreterGenerator::trace_bytecode(Template* t) {
   // The run-time runtime saves the right registers, depending on
   // the tosca in-state for the given template.
 
-  assert(Interpreter::trace_code(t->tos_in()) != NULL,
+  assert(Interpreter::trace_code(t->tos_in()) != nullptr,
          "entry must have been generated");
 
   // Note: we destroy LR here.
diff --git a/src/hotspot/cpu/ppc/templateTable_ppc_64.cpp b/src/hotspot/cpu/ppc/templateTable_ppc_64.cpp
index 79f81e23032..1140a1a9cbe 100644
--- a/src/hotspot/cpu/ppc/templateTable_ppc_64.cpp
+++ b/src/hotspot/cpu/ppc/templateTable_ppc_64.cpp
@@ -313,7 +313,7 @@ void TemplateTable::fast_aldc(LdcType type) {
   __ get_cache_index_at_bcp(R31, 1, index_size);  // Load index.
   __ load_resolved_reference_at_index(R17_tos, R31, R11_scratch1, R12_scratch2, &is_null);
 
-  // Convert null sentinel to NULL
+  // Convert null sentinel to null
   int simm16_rest = __ load_const_optimized(R11_scratch1, Universe::the_null_sentinel_addr(), R0, true);
   __ ld(R31, simm16_rest, R11_scratch1);
   __ resolve_oop_handle(R31, R11_scratch1, R12_scratch2, MacroAssembler::PRESERVATION_NONE);
@@ -995,7 +995,7 @@ void TemplateTable::aastore() {
   // Rindex is dead!
   Register Rscratch3 = Rindex;
 
-  // Do array store check - check for NULL value first.
+  // Do array store check - check for null value first.
   __ cmpdi(CCR0, R17_tos, 0);
   __ beq(CCR0, Lis_null);
 
@@ -2240,7 +2240,7 @@ void TemplateTable::resolve_cache_and_index(int byte_no, Register Rcache, Regist
 
     __ load_resolved_method_at_index(byte_no, Rcache, method);
     __ load_method_holder(klass, method);
-    __ clinit_barrier(klass, R16_thread, NULL /*L_fast_path*/, &L_clinit_barrier_slow);
+    __ clinit_barrier(klass, R16_thread, nullptr /*L_fast_path*/, &L_clinit_barrier_slow);
   }
 
   __ bind(Ldone);
@@ -2457,7 +2457,7 @@ void TemplateTable::jvmti_post_field_access(Register Rcache, Register Rscratch,
       }
       __ verify_oop(R17_tos);
     }
-    // tos:   object pointer or NULL if static
+    // tos:   object pointer or null if static
     // cache: cache entry pointer
     __ call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::post_field_access), R17_tos, Rcache);
     if (!is_static && has_tos) {
@@ -3546,7 +3546,7 @@ void TemplateTable::invokevfinal_helper(Register Rmethod, Register Rflags, Regis
   __ sldi(Rret_type, Rret_type, LogBytesPerWord);
   __ ldx(Rret_addr, Rret_type, Rtable_addr);
 
-  // Load receiver and receiver NULL check.
+  // Load receiver and receiver null check.
   __ load_receiver(Rnum_params, Rrecv);
   __ null_check_throw(Rrecv, -1, Rscratch1);
 
@@ -3570,7 +3570,7 @@ void TemplateTable::invokespecial(int byte_no) {
 
   prepare_invoke(byte_no, Rmethod, Rret_addr, noreg, Rreceiver, Rflags, R11_scratch1, R12_scratch2);
 
-  // Receiver NULL check.
+  // Receiver null check.
   __ null_check_throw(Rreceiver, -1, R11_scratch1);
 
   __ profile_call(R11_scratch1, R12_scratch2);
@@ -3705,7 +3705,7 @@ void TemplateTable::invokeinterface(int byte_no) {
   __ profile_arguments_type(Rmethod2, Rscratch1, Rscratch2, true);
   __ call_from_interpreter(Rmethod2, Rret_addr, Rscratch1, Rscratch2);
 
-  // Vtable entry was NULL => Throw abstract method error.
+  // Vtable entry was null => Throw abstract method error.
   __ bind(Lthrow_ame);
   // Pass arguments for generating a verbose error message.
   call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::throw_AbstractMethodErrorVerbose),
diff --git a/src/hotspot/cpu/ppc/vm_version_ppc.cpp b/src/hotspot/cpu/ppc/vm_version_ppc.cpp
index 7650f7c2f16..8db4adeb9ae 100644
--- a/src/hotspot/cpu/ppc/vm_version_ppc.cpp
+++ b/src/hotspot/cpu/ppc/vm_version_ppc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2020 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -427,7 +427,7 @@ void VM_Version::check_virtualizations() {
 #if defined(_AIX)
   int rc = 0;
   perfstat_partition_total_t pinfo;
-  rc = perfstat_partition_total(NULL, &pinfo, sizeof(perfstat_partition_total_t), 1);
+  rc = perfstat_partition_total(nullptr, &pinfo, sizeof(perfstat_partition_total_t), 1);
   if (rc == 1) {
     Abstract_VM_Version::_detected_virtualization = PowerVM;
   }
@@ -437,14 +437,14 @@ void VM_Version::check_virtualizations() {
   // e.g. system_type=IBM pSeries (emulated by qemu)
   char line[500];
   FILE* fp = os::fopen(info_file, "r");
-  if (fp == NULL) {
+  if (fp == nullptr) {
     return;
   }
   const char* system_type="system_type=";  // in case this line contains qemu, it is KVM
   const char* num_lpars="NumLpars="; // in case of non-KVM : if this line is found it is PowerVM
   bool num_lpars_found = false;
 
-  while (fgets(line, sizeof(line), fp) != NULL) {
+  while (fgets(line, sizeof(line), fp) != nullptr) {
     if (strncmp(line, system_type, strlen(system_type)) == 0) {
       if (strstr(line, "qemu") != 0) {
         Abstract_VM_Version::_detected_virtualization = PowerKVM;
@@ -472,7 +472,7 @@ void VM_Version::print_platform_virtualization_info(outputStream* st) {
   int rc = 0;
   perfstat_partition_total_t pinfo;
   memset(&pinfo, 0, sizeof(perfstat_partition_total_t));
-  rc = perfstat_partition_total(NULL, &pinfo, sizeof(perfstat_partition_total_t), 1);
+  rc = perfstat_partition_total(nullptr, &pinfo, sizeof(perfstat_partition_total_t), 1);
   if (rc != 1) {
     return;
   } else {
@@ -481,7 +481,7 @@ void VM_Version::print_platform_virtualization_info(outputStream* st) {
   // CPU information
   perfstat_cpu_total_t cpuinfo;
   memset(&cpuinfo, 0, sizeof(perfstat_cpu_total_t));
-  rc = perfstat_cpu_total(NULL, &cpuinfo, sizeof(perfstat_cpu_total_t), 1);
+  rc = perfstat_cpu_total(nullptr, &cpuinfo, sizeof(perfstat_cpu_total_t), 1);
   if (rc != 1) {
     return;
   }
@@ -532,7 +532,7 @@ void VM_Version::print_platform_virtualization_info(outputStream* st) {
                        "pool=", // CPU-pool number
                        "pool_capacity=",
                        "NumLpars=", // on non-KVM machines, NumLpars is not found for full partition mode machines
-                       NULL };
+                       nullptr };
   if (!print_matching_lines_from_file(info_file, st, kw)) {
     st->print_cr("  <%s Not Available>", info_file);
   }
diff --git a/src/hotspot/cpu/ppc/vtableStubs_ppc_64.cpp b/src/hotspot/cpu/ppc/vtableStubs_ppc_64.cpp
index a2475866e37..9afb35d8772 100644
--- a/src/hotspot/cpu/ppc/vtableStubs_ppc_64.cpp
+++ b/src/hotspot/cpu/ppc/vtableStubs_ppc_64.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -49,9 +49,9 @@ VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
   // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
   const int stub_code_length = code_size_limit(true);
   VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index);
-  // Can be NULL if there is no free space in the code cache.
-  if (s == NULL) {
-    return NULL;
+  // Can be null if there is no free space in the code cache.
+  if (s == nullptr) {
+    return nullptr;
   }
 
   // Count unused bytes in instruction sequences of variable size.
@@ -120,7 +120,7 @@ VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
                               // if the vtable entry is null, the method is abstract
                               // NOTE: for vtable dispatches, the vtable entry will never be null.
 
-  __ null_check(R19_method, in_bytes(Method::from_compiled_offset()), /*implicit only*/NULL);
+  __ null_check(R19_method, in_bytes(Method::from_compiled_offset()), /*implicit only*/nullptr);
   __ ld(R12_scratch2, in_bytes(Method::from_compiled_offset()), R19_method);
   __ mtctr(R12_scratch2);
   __ bctr();
@@ -135,9 +135,9 @@ VtableStub* VtableStubs::create_itable_stub(int itable_index) {
   // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
   const int stub_code_length = code_size_limit(false);
   VtableStub* s = new(stub_code_length) VtableStub(false, itable_index);
-  // Can be NULL if there is no free space in the code cache.
-  if (s == NULL) {
-    return NULL;
+  // Can be null if there is no free space in the code cache.
+  if (s == nullptr) {
+    return nullptr;
   }
 
   // Count unused bytes in instruction sequences of variable size.