RFR: JDK-8301494: Replace NULL with nullptr in cpu/arm

[Johan Sjölen]

On Tue, 31 Jan 2023 11:39:38 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

> Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory cpu/arm. 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!

Some minor fixes needed.

src/hotspot/cpu/arm/interp_masm_arm.cpp line 163:

> 161: 
> 162:     ldr(thread_state, Address(Rthread, JavaThread::jvmti_thread_state_offset()));
> 163:     cbz(thread_state, L); // if (thread->jvmti_thread_state() == null) exit;

nullptr

src/hotspot/cpu/arm/stubGenerator_arm.cpp line 2656:

> 2654:     __ b(L_failed, lt);
> 2655: 
> 2656:     //  if (dst == null) return -1;

nullptr

src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp line 760:

> 758:   const int referent_offset = java_lang_ref_Reference::referent_offset();
> 759: 
> 760:   // Check if local 0 != null

nullptr

src/hotspot/cpu/arm/templateTable_arm.cpp line 4083:

> 4081:   // result = 0: obj == null or  obj is not an instanceof the specified klass
> 4082:   // result = 1: obj != null and obj is     an instanceof the specified klass
> 4083: 

nullptr

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PR: https://git.openjdk.org/jdk/pull/12322