RFR: JDK-8301076: Replace NULL with nullptr in share/prims/

[Johan Sjölen]

On Wed, 25 Jan 2023 11:47:05 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

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

Passes tier1.

src/hotspot/share/prims/jni.cpp line 2234:

> 2232:   if (s_value != nullptr) {
> 2233:     size_t length = java_lang_String::utf8_length(java_string, s_value);
> 2234:     /* JNI Specification states return nullptr on OOM */

null

src/hotspot/share/prims/jni.cpp line 2420:

> 2418:       *isCopy = JNI_FALSE; \
> 2419:     } \
> 2420:     /* Empty array: legal but useless, can't return nullptr. \

null

src/hotspot/share/prims/jni.cpp line 2425:

> 2423:     result = (ElementType*)get_bad_address(); \
> 2424:   } else { \
> 2425:     /* JNI Specification states return nullptr on OOM */                    \

null

src/hotspot/share/prims/jni.cpp line 2839:

> 2837:     int s_len = java_lang_String::length(s, s_value);
> 2838:     ret = NEW_C_HEAP_ARRAY_RETURN_NULL(jchar, s_len + 1, mtInternal);  // add one for zero termination
> 2839:     /* JNI Specification states return nullptr on OOM */

null

src/hotspot/share/prims/jniCheck.cpp line 95:

> 93:   result_type JNICALL header {                                           \
> 94:     Thread* cur = Thread::current_or_null();                             \
> 95:     if (cur == nullptr || !cur->is_Java_thread()) {                         \

align

src/hotspot/share/prims/jniCheck.cpp line 935:

> 933:     va_list args; \
> 934:     IN_VM( \
> 935:       jniCheck::validate_call(thr, nullptr, methodID, obj); \

align

src/hotspot/share/prims/jniCheck.cpp line 953:

> 951:     functionEnter(thr); \
> 952:     IN_VM(\
> 953:       jniCheck::validate_call(thr, nullptr, methodID, obj); \

align

src/hotspot/share/prims/jniCheck.cpp line 969:

> 967:     functionEnter(thr); \
> 968:     IN_VM( \
> 969:       jniCheck::validate_call(thr, nullptr, methodID, obj); \

align

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

PR: https://git.openjdk.org/jdk/pull/12188