RFR: JDK-8301495: Replace NULL with nullptr in cpu/ppc

[Richard Reingruber]

On Tue, 31 Jan 2023 11:39:48 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

> Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory cpu/ppc. Unfortunately the script that does the change isn't perfect, and so we
> need to comb through these manually to make sure nothing has gone wrong. I also review these changes but things slip past my eyes sometimes.
> 
> Here are some typical things to look out for:
> 
> 1. No changes but copyright header changed (probably because I reverted some changes but forgot the copyright).
> 2. Macros having their NULL changed to nullptr, these are added to the script when I find them. They should be NULL.
> 3. nullptr in comments and logs. We try to use lower case "null" in these cases as it reads better. An exception is made when code expressions are in a comment.
> 
> An example of this:
> 
> ```c++
> // This function returns null
> void* ret_null();
> // This function returns true if *x == nullptr
> bool is_nullptr(void** x);
> 
> 
> Note how `nullptr` participates in a code expression here, we really are talking about the specific value `nullptr`.
> 
> Thanks!

Looks good, just a few changes I'd like to suggest.

Thanks, Richard.

src/hotspot/cpu/ppc/abstractInterpreter_ppc.cpp line 97:

> 95: // Parameters:
> 96: //
> 97: // interpreter_frame != null:

Suggestion:

// interpreter_frame != nullptr:

src/hotspot/cpu/ppc/frame_ppc.cpp line 114:

> 112: 
> 113:     // At this point, there still is a chance that fp_safe is false.
> 114:     // In particular, (fp == null) might be true. So let's check and

Suggestion:

    // In particular, (fp == nullptr) might be true. So let's check and

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 920:

> 918:     // } else if (THREAD->is_lock_owned((address)displaced_header))
> 919:     //   // Simple recursive case.
> 920:     //   monitor->lock()->set_displaced_header(null);

Suggestion:

    //   monitor->lock()->set_displaced_header(nullptr);

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 981:

> 979:     // } else if (THREAD->is_lock_owned((address)displaced_header))
> 980:     //   // Simple recursive case.
> 981:     //   monitor->lock()->set_displaced_header(null);

Suggestion:

    //   monitor->lock()->set_displaced_header(nullptr);

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 1031:

> 1029:     // template code:
> 1030:     //
> 1031:     // if ((displaced_header = monitor->displaced_header()) == null) {

Suggestion:

    // if ((displaced_header = monitor->displaced_header()) == nullptr) {

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 1033:

> 1031:     // if ((displaced_header = monitor->displaced_header()) == null) {
> 1032:     //   // Recursive unlock. Mark the monitor unlocked by setting the object field to null.
> 1033:     //   monitor->set_obj(null);

Suggestion:

    //   monitor->set_obj(nullptr);

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 1036:

> 1034:     // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
> 1035:     //   // We swapped the unlocked mark in displaced_header into the object's mark word.
> 1036:     //   monitor->set_obj(null);

Suggestion:

    //   monitor->set_obj(nullptr);

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 1062:

> 1060:     // } else if (Atomic::cmpxchg(obj->mark_addr(), monitor, displaced_header) == monitor) {
> 1061:     //   // We swapped the unlocked mark in displaced_header into the object's mark word.
> 1062:     //   monitor->set_obj(null);

Suggestion:

    //   monitor->set_obj(nullptr);

src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp line 1097:

> 1095:     b(done); // Monitor register may be overwritten! Runtime has already freed the slot.
> 1096: 
> 1097:     // Exchange worked, do monitor->set_obj(null);

Suggestion:

    // Exchange worked, do monitor->set_obj(nullptr);

src/hotspot/cpu/ppc/interpreterRT_ppc.cpp line 102:

> 100: 
> 101:   // The handle for a receiver will never be null.
> 102:   bool do_nullptr_check = offset() != 0 || is_static();

Suggestion:

  bool do_null_check = offset() != 0 || is_static();

src/hotspot/cpu/ppc/interpreterRT_ppc.cpp line 105:

> 103: 
> 104:   Label do_null;
> 105:   if (do_nullptr_check) {

Suggestion:

  if (do_null_check) {

src/hotspot/cpu/ppc/stubGenerator_ppc.cpp line 2421:

> 2419:     BLOCK_COMMENT("arraycopy initial argument checks");
> 2420: 
> 2421:     __ cmpdi(CCR1, src, 0);      // if (src == null) return -1;

Suggestion:

    __ cmpdi(CCR1, src, 0);      // if (src == nullptr) return -1;

src/hotspot/cpu/ppc/stubGenerator_ppc.cpp line 2423:

> 2421:     __ cmpdi(CCR1, src, 0);      // if (src == null) return -1;
> 2422:     __ extsw_(src_pos, src_pos); // if (src_pos < 0) return -1;
> 2423:     __ cmpdi(CCR5, dst, 0);      // if (dst == null) return -1;

Suggestion:

    __ cmpdi(CCR5, dst, 0);      // if (dst == nullptr) return -1;

src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp line 525:

> 523:   __ ld(R3_RET, Interpreter::stackElementSize, R15_esp); // get receiver
> 524: 
> 525:   // Check if receiver == null and go the slow path.

Suggestion:

  // Check if receiver == nullptr and go the slow path.

-------------

Changes requested by rrich (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12323