JDK-8301477: Replace NULL with nullptr in os/aix

[jdksjolen]

Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory os/aix. 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:

// 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-8301477: Replace NULL with nullptr in os/aix

Reviewers

• Thomas Stuefe (@tstuefe - Reviewer) ⚠️ Review applies to f1968b0f
• Coleen Phillimore (@coleenp - Reviewer) ⚠️ Review applies to f1968b0f
• Tyler Steele (@backwaterred - Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/12313/head:pull/12313
$ git checkout pull/12313

Update a local copy of the PR:
$ git checkout pull/12313
$ git pull https://git.openjdk.org/jdk pull/12313/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 12313

View PR using the GUI difftool:
$ git pr show -t 12313

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/12313.diff

[bridgekeeper]

👋 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]

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

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[mlbridge]

Webrevs

• 01: Full - Incremental (89caf7bf)
• 00: Full (f1968b0f)

[tstuefe]

LGTM.

My eyes still twitch a bit each time I read "null" in comments, though ;-)

[openjdk]

@jdksjolen This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8301477: Replace NULL with nullptr in os/aix

Reviewed-by: stuefe, coleenp, tsteele

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 459 new commits pushed to the master branch:

• 55e6bb6: 8302685: Some javac unit tests aren't reliably closing open files
• f5a1276: 8262895: [macos_aarch64] runtime/CompressedOops/CompressedClassPointers.java fails with 'Narrow klass base: 0x0000000000000000' missing from stdout/stderr
• 2fe4e5f: 8303169: Remove Windows specific workaround from libdt
• f2b03f9: 8303051: Stop saving 5 chunks in each ChunkPool
• fbc036e: 8303135: JFR: Log periodic events using periodic tag
• dbb5581: 8081474: SwingWorker calls 'done' before the 'doInBackground' is finished
• 306134d: 8300792: Refactor examples in java.net.http to use @snippet
• a2c5a4a: 8302732: sun/net/www/http/HttpClient/MultiThreadTest.java still failing intermittently
• db217c9: 8292583: Comment for ciArrayKlass::make is wrong
• 2613b94: 8302149: Speed up compiler/jsr292/methodHandleExceptions/TestAMEnotNPE.java
• ... and 449 more: https://git.openjdk.org/jdk/compare/107e184d59c0bbed6441a3c1a9bfd4527da3bce5...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[jdksjolen]

Hi @backwaterred, would you mind testing this patch to confirm that it works? Thanks!

[backwaterred]

Hi @backwaterred, would you mind testing this patch to confirm that it works? Thanks!

Hi @jdksjolen, compiling on AIX took a little bit of work. I can build with these changes. Let me know if there is a more convenient way to get them to you.

Testing is underway. I will post when it completes.

[backwaterred]

With the patch I added above, testing on AIX looks good. Thanks for your work on these changes, and for pinging me to test them out.

[jdksjolen]

With the patch I added above, testing on AIX looks good. Thanks for your work on these changes, and for pinging me to test them out.

Hi, thanks for providing the patch. I applied it with two changes of my own:

-  size_t stack_size = (size_t)nullptr;
+  size_t stack_size = 0;

The line above is: stackptr_t stack_base = nullptr;, so it's likely that assigning both to NULL was a mistake that wasn't caught by the compiler (as NULL == 0).

And

-  while ((*pc2 != (size_t)nullptr) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
+ while ((*pc2 != 0) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {

Here I thought maybe we dereference the pointer by accident, and we really meant while ((pc2 != nullptr)), but just below that we have:

  if (*pc2 != 0) {
    trcVerbose("no traceback table found");
    return false;
  }

It's unlikely you make the same mistake twice, and this time referring to the value as 0 instead of NULL.

[jdksjolen]

Thanks for the re-approval.

/integrate

[openjdk]

Going to push as commit 43288bb.
Since your change was applied there have been 568 commits pushed to the master branch:

• 008c5eb: 8303621: BitMap::iterate should support lambdas and other function objects
• 52d3008: 8303497: [s390x] ProblemList TestUnreachableInnerLoop.java
• 3f2d929: 8303511: C2: assert(get_ctrl(n) == cle_out) during unrolling
• 7fbfc88: 8303534: Merge CompactibleSpace into ContiguousSpace
• 97c25df: 8204550: NMT: RegionIterator does not need to keep _current_size
• 94eda53: 8201516: DebugNonSafepoints generates incorrect information
• c51d40c: 8303607: SunMSCAPI provider leaks memory and keys
• f64ed09: 8303540: Eliminate unnecessary reference to javac internal class
• ccfe167: 8298939: Refactor open/test/jdk/javax/rmi/ssl/SSLSocketParametersTest.sh to jtreg java test
• cfb0a25: 8303440: The "ZonedDateTime.parse" may not accept the "UTC+XX" zone id
• ... and 558 more: https://git.openjdk.org/jdk/compare/107e184d59c0bbed6441a3c1a9bfd4527da3bce5...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jdksjolen Pushed as commit 43288bb.

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