JDK-8301498: Replace NULL with nullptr in cpu/x86 #12326

jdksjolen · 2023-01-31T11:40:19Z

Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory cpu/x86. 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-8301498: Replace NULL with nullptr in cpu/x86

Reviewers

David Holmes (@dholmes-ora - Reviewer)
Vladimir Kozlov (@vnkozlov - Reviewer) ⚠️ Review applies to 0c18b898

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/12326/head:pull/12326
$ git checkout pull/12326

Update a local copy of the PR:
$ git checkout pull/12326
$ git pull https://git.openjdk.org/jdk.git pull/12326/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 12326

View PR using the GUI difftool:
$ git pr show -t 12326

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/12326.diff

bridgekeeper · 2023-01-31T11:42:30Z

👋 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 · 2023-01-31T11:48:43Z

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

hotspot
shenandoah

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

Some things to fix

jdksjolen · 2023-02-06T10:20:32Z

src/hotspot/cpu/x86/frame_x86.inline.hpp

  // value.
  // UPDATE: this constructor is only used by trace_method_handle_stub() now.
-  // assert(_pc != NULL, "no pc?");
+  // assert(_pc != null, "no pc?");


jdksjolen · 2023-02-06T10:20:48Z

src/hotspot/cpu/x86/gc/g1/g1BarrierSetAssembler_x86.cpp

  // Calling the runtime using the regular call_VM_leaf mechanism generates
  // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
-  // that checks that the *(ebp+frame::interpreter_frame_last_sp) == NULL.
+  // that checks that the *(ebp+frame::interpreter_frame_last_sp) == null.


jdksjolen · 2023-02-06T10:21:00Z

src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp

  // Calling the runtime using the regular call_VM_leaf mechanism generates
  // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
-  // that checks that the *(ebp+frame::interpreter_frame_last_sp) == NULL.
+  // that checks that the *(ebp+frame::interpreter_frame_last_sp) == null.


jdksjolen · 2023-02-06T10:21:10Z

src/hotspot/cpu/x86/icBuffer_x86.cpp

  // (1) the value is old (i.e., doesn't matter for scavenges)
  // (2) these ICStubs are removed *before* a GC happens, so the roots disappear
-  // assert(cached_value == NULL || cached_oop->is_perm(), "must be perm oop");
+  // assert(cached_value == null || cached_oop->is_perm(), "must be perm oop");


jdksjolen · 2023-02-06T10:21:19Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

    jcc(Assembler::equal, L);
    stop("InterpreterMacroAssembler::call_VM_base:"
-         " last_sp != NULL");
+         " last_sp != null");


jdksjolen · 2023-02-06T10:23:34Z

src/hotspot/cpu/x86/stubGenerator_x86_32.cpp

    __ jccb(Assembler::negative, L_failed_0);

-    //  if (dst == NULL) return -1;
+    //  if (dst == null) return -1;


jdksjolen · 2023-02-06T10:23:41Z

src/hotspot/cpu/x86/stubGenerator_x86_32.cpp

-    //  if (src->klass() == NULL) return -1;
+    //  if (src->klass() == null) return -1;
    Address src_klass_addr(src, oopDesc::klass_offset_in_bytes());
    Address dst_klass_addr(dst, oopDesc::klass_offset_in_bytes());
    const Register rcx_src_klass = rcx;    // array klass
    __ movptr(rcx_src_klass, Address(src, oopDesc::klass_offset_in_bytes()));

 #ifdef ASSERT
-    //  assert(src->klass() != NULL);
+    //  assert(src->klass() != null);


jdksjolen · 2023-02-06T10:24:02Z

src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp

  //

-  //  if (src == NULL) return -1;
+  //  if (src == null) return -1;


jdksjolen · 2023-02-06T10:24:06Z

src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp

  __ jccb(Assembler::negative, L_failed_0);

-  //  if (dst == NULL) return -1;
+  //  if (dst == null) return -1;


jdksjolen · 2023-02-06T10:24:15Z

src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp

  __ load_klass(r10_src_klass, src, rklass_tmp);
 #ifdef ASSERT
-  //  assert(src->klass() != NULL);
+  //  assert(src->klass() != null);


jdksjolen · 2023-02-10T09:40:02Z

Builds and sent out for testing.

mlbridge · 2023-02-10T09:45:40Z

Webrevs

jdksjolen · 2023-02-10T13:59:02Z

Passes tier1.

vnkozlov · 2023-02-10T22:43:54Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

    jcc(Assembler::equal, L);
    stop("InterpreterMacroAssembler::call_VM_base:"
-         " last_sp != NULL");
+         " last_sp != nullptr");


These are textual code fragments so I think nullptr is more appropriate - as per changes made to cpu/arm code.

dholmes-ora · 2023-02-13T01:31:21Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

    jcc(Assembler::equal, L);
    stop("InterpreterMacroAssembler::call_VM_base:"
-         " last_sp != NULL");
+         " last_sp != nullptr");


These are textual code fragments so I think nullptr is more appropriate - as per changes made to cpu/arm code.

dholmes-ora · 2023-02-13T01:31:29Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

    jcc(Assembler::equal, L);
    stop("InterpreterMacroAssembler::call_VM_leaf_base:"
-         " last_sp != NULL");
+         " last_sp != null");


dholmes-ora · 2023-02-13T01:33:56Z

src/hotspot/cpu/x86/macroAssembler_x86.cpp

 void MacroAssembler::null_check(Register reg, int offset) {
  if (needs_explicit_null_check(offset)) {
-    // provoke OS NULL exception if reg = NULL by
+    // provoke OS null exception if reg = null by


suggestion "reg is null"

dholmes-ora · 2023-02-13T01:34:53Z

src/hotspot/cpu/x86/macroAssembler_x86.cpp

  } else {
    // nothing to do, (later) access of M[reg + offset]
-    // will provoke OS NULL exception if reg = NULL
+    // will provoke OS null exception if reg = null


suggestion: "reg is null"

dholmes-ora · 2023-02-13T01:36:06Z

src/hotspot/cpu/x86/macroAssembler_x86.hpp

+  // Support for null-checks
  //
-  // Generates code that causes a NULL OS exception if the content of reg is NULL.
+  // Generates code that causes a null OS exception if the content of reg is null.


Note use of "reg is null" here :)

dholmes-ora · 2023-02-13T01:38:08Z

src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp

                                       in_ByteSize(-1),
                                       in_ByteSize(-1),
-                                       (OopMapSet*)NULL);
+                                       (OopMapSet*)nullptr);


Unnecessary cast?

dholmes-ora · 2023-02-13T01:41:53Z

src/hotspot/cpu/x86/templateTable_x86.cpp

+  // rax = 0: obj == null or  obj is not an instanceof the specified klass
+  // rax = 1: obj != null and obj is     an instanceof the specified klass


jdksjolen · 2023-02-13T09:22:02Z

I added the fixes, thanks! Last commit passed tier1.

dholmes-ora

LGTM! Thanks

openjdk · 2023-02-14T06:30:49Z

@jdksjolen this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout JDK-8301498
git fetch https://git.openjdk.org/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

vnkozlov

In addition to few missed placed I noticed that you keep mov_metadata(rbx, (Metadata*)nullptr); casting.

Is Metadata* something special we need to cast it?

And more general question - do we need to keep some casting for nullptr?
We kept them in previous PRs which are already pushed #12029

Should we update our "spec" for nullptr to remove all casting or keep some? What is condition to keep?

vnkozlov · 2023-02-14T19:01:34Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

    movptr(tmp, Address(rthread, JavaThread::jvmti_thread_state_offset()));
    testptr(tmp, tmp);
-    jcc(Assembler::zero, L); // if (thread->jvmti_thread_state() == NULL) exit;
+    jcc(Assembler::zero, L); // if (thread->jvmti_thread_state() == null) exit;


Missed change to nullptr as you suggested.

vnkozlov · 2023-02-14T19:01:46Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

 //   // main copy of decision tree, rooted at row[1]
 //   if (row[0].rec == rec) { row[0].incr(); goto done; }
-//   if (row[0].rec != NULL) {
+//   if (row[0].rec != null) {


Missed change to nullptr as you suggested.

vnkozlov · 2023-02-14T19:02:05Z

src/hotspot/cpu/x86/interp_masm_x86.cpp

-//     if (row[1].rec != NULL) {
+//     if (row[1].rec != null) {
 //       // degenerate decision tree, rooted at row[2]
 //       if (row[2].rec == rec) { row[2].incr(); goto done; }
-//       if (row[2].rec != NULL) { count.incr(); goto done; } // overflow
+//       if (row[2].rec != null) { count.incr(); goto done; } // overflow


Missed change to nullptr.

vnkozlov · 2023-02-14T19:02:40Z

src/hotspot/cpu/x86/macroAssembler_x86.cpp

  }

-  // for (scan = klass->itable(); scan->interface() != NULL; scan += scan_step) {
+  // for (scan = klass->itable(); scan->interface() != null; scan += scan_step) {


Missed change to nullptr as you suggested.

bridgekeeper · 2023-03-14T23:30:35Z

@jdksjolen This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

jdksjolen · 2023-03-15T11:03:57Z

Hi Vladimir!

I applied your changes, thanks for the review.

vnkozlov

Looks good.

dholmes-ora

Still good. Thanks.

openjdk · 2023-03-21T09:59:55Z

@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:

8301498: Replace NULL with nullptr in cpu/x86

Reviewed-by: dholmes, kvn

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 74 new commits pushed to the master branch:

0156909: 8304502: Classfile API class hierarchy makes assumptions when class is not resolved
0deb648: 8290200: com/sun/jdi/InvokeHangTest.java fails with "Debuggee appears to be hung"
019fcd8: 8304139: Add and method constants to ConstantDescs
d6f20e2: 8304680: Problemlist compiler/sharedstubs/SharedStubToInterpTest.java
d788a1b: 8304180: Constant Descriptors for MethodHandles::classData and classDataAt
bbde215: 8299494: Test vmTestbase/nsk/stress/except/except011.java failed: ExceptionInInitializerError: target class not found
1c04686: 8304387: Fix positions of shared static stubs / trampolines
c65bb2c: 8304334: java/awt/color/ICC_ColorSpace/ToFromCIEXYZRoundTrip.java times out on slow platforms
4bf1fbb: 8303648: Add String.indexOf(String str, int beginIndex, int endIndex)
c4df9b5: 8304537: Ant-based langtools build fails after JDK-8015831 Add lint check for calling overridable methods from a constructor
... and 64 more: https://git.openjdk.org/jdk/compare/e3777b0c49abb9cc1925f4044392afadf3adef61...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.

dholmes-ora

Still good. Thanks.

(incremental change looked weird but end result seems fine)

jdksjolen · 2023-03-22T14:17:20Z

Thanks. All of tier1 and tier2 is passing.

/integrate

openjdk · 2023-03-22T14:18:50Z

Going to push as commit 4154a98.
Since your change was applied there have been 80 commits pushed to the master branch:

ddf1e34: 8304089: Convert TraceDependencies to UL
358c61b: 8294972: Convert jdk.jlink internal plugins to use the Classfile API
c74507e: 8304657: G1: Rename set_state_empty to set_state_untracked
ca94287: 8304144: G1: Remove unnecessary is_survivor check in G1ClearCardTableTask
eda0065: 8304286: java/net/SocketOption/OptionsTest.java failing after JDK-8302659
c039d26: 8303804: Fix some errors of If-VectorTest and CMove-VectorTest
0156909: 8304502: Classfile API class hierarchy makes assumptions when class is not resolved
0deb648: 8290200: com/sun/jdi/InvokeHangTest.java fails with "Debuggee appears to be hung"
019fcd8: 8304139: Add and method constants to ConstantDescs
d6f20e2: 8304680: Problemlist compiler/sharedstubs/SharedStubToInterpTest.java
... and 70 more: https://git.openjdk.org/jdk/compare/e3777b0c49abb9cc1925f4044392afadf3adef61...master

Your commit was automatically rebased without conflicts.

openjdk · 2023-03-22T14:19:10Z

@jdksjolen Pushed as commit 4154a98.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

Replace NULL with nullptr in cpu/x86

02ad1db

openjdk bot added hotspot hotspot-dev@openjdk.org shenandoah shenandoah-dev@openjdk.org labels Jan 31, 2023

jdksjolen commented Feb 6, 2023

View reviewed changes

Fixes

432ec5d

jdksjolen marked this pull request as ready for review February 10, 2023 09:39

openjdk bot added the rfr Pull request is ready for review label Feb 10, 2023

vnkozlov reviewed Feb 10, 2023

View reviewed changes

dholmes-ora reviewed Feb 13, 2023

View reviewed changes

Some more fixes

e074744

dholmes-ora approved these changes Feb 14, 2023

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openjdk bot added the merge-conflict Pull request has merge conflict with target branch label Feb 14, 2023

vnkozlov suggested changes Feb 14, 2023

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Merge remote-tracking branch 'origin/master' into JDK-8301498

5a55cdb

Fix vnkozlov's suggestions

0c18b89

vnkozlov approved these changes Mar 15, 2023

View reviewed changes

dholmes-ora approved these changes Mar 16, 2023

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Merge remote-tracking branch 'origin/master' into JDK-8301498

dd79b17

openjdk bot added ready Pull request is ready to be integrated and removed merge-conflict Pull request has merge conflict with target branch labels Mar 21, 2023

dholmes-ora approved these changes Mar 22, 2023

View reviewed changes

openjdk bot added the integrated Pull request has been integrated label Mar 22, 2023

openjdk bot closed this Mar 22, 2023

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Mar 22, 2023

		// rax = 0: obj == null or obj is not an instanceof the specified klass
		// rax = 1: obj != null and obj is an instanceof the specified klass

JDK-8301498: Replace NULL with nullptr in cpu/x86 #12326

JDK-8301498: Replace NULL with nullptr in cpu/x86 #12326

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jdksjolen commented Jan 31, 2023 •

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