JDK-8301076: Replace NULL with nullptr in share/prims/ #12188

jdksjolen · 2023-01-25T11:47:05Z

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:

No changes but copyright header changed (probably because I reverted some changes but forgot the copyright).
Macros having their NULL changed to nullptr, these are added to the script when I find them. They should be NULL.
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:

// 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!

Progress

Change must be properly reviewed (1 review required, with at least 1 Reviewer)
Change must not contain extraneous whitespace
Commit message must refer to an issue

Issue

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

Reviewers

Kim Barrett (@kimbarrett - Reviewer) ⚠️ Review applies to b1ff44d7
David Holmes (@dholmes-ora - Reviewer) ⚠️ Review applies to b1ff44d7

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/12188/head:pull/12188
$ git checkout pull/12188

Update a local copy of the PR:
$ git checkout pull/12188
$ git pull https://git.openjdk.org/jdk pull/12188/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 12188

View PR using the GUI difftool:
$ git pr show -t 12188

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/12188.diff

bridgekeeper · 2023-01-25T11:49:53Z

👋 Welcome back jsjolen! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2023-01-25T11:53:42Z

@jdksjolen The following labels will be automatically applied to this pull request:

hotspot
serviceability

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

jdksjolen · 2023-01-26T16:10:15Z

src/hotspot/share/prims/jni.cpp

    size_t length = java_lang_String::utf8_length(java_string, s_value);
-    /* JNI Specification states return NULL on OOM */
+    /* JNI Specification states return nullptr on OOM */


jdksjolen · 2023-01-26T16:10:26Z

src/hotspot/share/prims/jni.cpp

      *isCopy = JNI_FALSE; \
    } \
-    /* Empty array: legal but useless, can't return NULL. \
+    /* Empty array: legal but useless, can't return nullptr. \


jdksjolen · 2023-01-26T16:10:29Z

src/hotspot/share/prims/jni.cpp

     * Return a pointer to something useless. \
     * Avoid asserts in typeArrayOop. */ \
    result = (ElementType*)get_bad_address(); \
  } else { \
-    /* JNI Specification states return NULL on OOM */                    \
+    /* JNI Specification states return nullptr on OOM */                    \


jdksjolen · 2023-01-26T16:10:38Z

src/hotspot/share/prims/jni.cpp

  } else {
    // Inflate latin1 encoded string to UTF16
    typeArrayOop s_value = java_lang_String::value(s);
    int s_len = java_lang_String::length(s, s_value);
    ret = NEW_C_HEAP_ARRAY_RETURN_NULL(jchar, s_len + 1, mtInternal);  // add one for zero termination
-    /* JNI Specification states return NULL on OOM */
-    if (ret != NULL) {
+    /* JNI Specification states return nullptr on OOM */


jdksjolen · 2023-01-26T16:10:55Z

src/hotspot/share/prims/jniCheck.cpp

@@ -92,7 +92,7 @@ static struct JNINativeInterface_ * unchecked_jni_NativeInterface;
 extern "C" {                                                             \
  result_type JNICALL header {                                           \
    Thread* cur = Thread::current_or_null();                             \
-    if (cur == NULL || !cur->is_Java_thread()) {                         \
+    if (cur == nullptr || !cur->is_Java_thread()) {                         \


jdksjolen · 2023-01-26T16:11:14Z

src/hotspot/share/prims/jniCheck.cpp

@@ -932,7 +932,7 @@ JNI_ENTRY_CHECKED(ResultType,  \
    functionEnter(thr); \
    va_list args; \
    IN_VM( \
-      jniCheck::validate_call(thr, NULL, methodID, obj); \
+      jniCheck::validate_call(thr, nullptr, methodID, obj); \


Not aligned from start, not fixing.

jdksjolen · 2023-01-26T16:11:19Z

src/hotspot/share/prims/jniCheck.cpp

@@ -950,7 +950,7 @@ JNI_ENTRY_CHECKED(ResultType,  \
                                    va_list args)) \
    functionEnter(thr); \
    IN_VM(\
-      jniCheck::validate_call(thr, NULL, methodID, obj); \
+      jniCheck::validate_call(thr, nullptr, methodID, obj); \


Not aligned from start, not fixing.

jdksjolen · 2023-01-26T16:11:25Z

src/hotspot/share/prims/jniCheck.cpp

@@ -966,7 +966,7 @@ JNI_ENTRY_CHECKED(ResultType,  \
                                    const jvalue * args)) \
    functionEnter(thr); \
    IN_VM( \
-      jniCheck::validate_call(thr, NULL, methodID, obj); \
+      jniCheck::validate_call(thr, nullptr, methodID, obj); \


Not aligned from start, not fixing.

jdksjolen · 2023-01-26T16:25:29Z

Passes tier1.

mlbridge · 2023-01-26T16:31:10Z

Webrevs

alexmenkov · 2023-01-27T20:43:30Z

src/hotspot/share/prims/jvmtiImpl.hpp

-// Utility macro that checks for NULL pointers:
-#define NULL_CHECK(X, Y) if ((X) == NULL) { return (Y); }
+// Utility macro that checks for null pointers:
+#NULL nullptr_CHECK(X, Y) if ((X) == nullptr) { return (Y); }


causes compilation error

kimbarrett · 2023-01-28T23:50:04Z

src/hotspot/share/prims/jvmtiEnvThreadState.cpp

 }

 bool JvmtiEnvThreadState::is_virtual() {
  return _state->is_virtual();
 }

-// Use _thread_saved if cthread is detached from JavaThread (_thread == NULL).
+// Use _thread_saved if cthread is detached from JavaThread (_thread == null).


s/null/nullptr/ or s/==/is/

kimbarrett · 2023-01-28T23:55:17Z