8294293: Remove unused _width and _newlines field in outputStream #10411

jdksjolen · 2022-09-23T15:59:39Z

_width is unused so I deleted it
_newlines was used in one place, and only to check if any new lines had been seen. I removed _newlines and instead used update_position's unused return value to indicate whether any newlines has been seen. This required expanding the call of xmlTextStream::write in defaultStream.

This removes some cruft from outputStream and saves us 8 bytes on the size of outputStream.

I also noted that _position isn't number of chars into a line, but rather a "visual position". It's a bit surprising, which is why I added this comment. This can be seen in the \t case in update_position.

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Issue

JDK-8294293: Remove unused _width and _newlines field in outputStream

Reviewers

Robbin Ehn (@robehn - Reviewer) ⚠️ Review applies to 18847c61
David Holmes (@dholmes-ora - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/10411/head:pull/10411
$ git checkout pull/10411

Update a local copy of the PR:
$ git checkout pull/10411
$ git pull https://git.openjdk.org/jdk pull/10411/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 10411

View PR using the GUI difftool:
$ git pr show -t 10411

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Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/10411.diff

bridgekeeper · 2022-09-23T16:01:45Z

👋 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 · 2022-09-23T16:16:48Z

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

hotspot

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

mlbridge · 2022-09-23T16:20:15Z

Webrevs

01: Full - Incremental (11977a50)
00: Full (18847c61)

robehn

Looks good, thanks!

robehn · 2022-09-26T07:02:28Z

src/hotspot/share/utilities/ostream.hpp

@@ -86,7 +86,6 @@ class outputStream : public ResourceObj {
   void move_to(int col, int slop = 6, int min_space = 2);

   // sizing
-   int width()    const { return _width;    }
   int position() const { return _position; }
   julong count() const { return _precount + _position; }
   void set_count(julong count) { _precount = count - _position; }


These julong should probably be uint64_t.
But it may cause some more changes, e.g. _file_end in CompileLog should then also probably also be uint64_t.
We can look at that in another RFE.

openjdk · 2022-09-26T07:04:52Z

@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:

8294293: Remove unused _width and _newlines field in outputStream

Reviewed-by: rehn, dholmes

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 104 new commits pushed to the master branch:

94e14da: 8294057: Parallel: Tighten ParallelCompactData::initialize_region_data
1ea0d6b: 8292301: [REDO v2] C2 crash when allocating array of size too large
c13e0ef: 8292848: AWT_Mixing and TrayIcon tests fail on el8 with hard-coded isOel7
79ccc79: 8293613: need to properly handle and hide tmp VTMS transitions
5e1e449: 8290920: sspi_bridge.dll not built if BUILD_CRYPTO is false
d827fd8: 8294430: RISC-V: Small refactoring for movptr_with_offset
9d76ac8: 8292158: AES-CTR cipher state corruption with AVX-512
e5b65c4: 8290482: Update JNI Specification of DestroyJavaVM for better alignment with JLS, JVMS, and Java SE API Specifications
f8d9fa8: 8294483: Remove vmTestbase/nsk/jvmti/GetThreadState tests.
6ad151d: 8293143: Workaround for JDK-8292217 when doing "step over" of bytecode with unresolved cp reference
... and 94 more: https://git.openjdk.org/jdk/compare/bb422f5c14745bf29bc2cb741f819a17c8400543...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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@robehn, @dholmes-ora) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

dholmes-ora

Generally seems okay but a couple of queries.

Thanks.

dholmes-ora · 2022-09-26T08:08:25Z

src/hotspot/share/utilities/ostream.hpp

@@ -29,6 +29,7 @@
 #include "runtime/timer.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/macros.hpp"
+#include <cstdint>


This std header doesn't seem to be used anywhere else in hotspot code - why do we need it here?

Good catch, it's been removed.

dholmes-ora · 2022-09-26T08:11:53Z

src/hotspot/share/utilities/ostream.cpp

    // print to output stream. It can be redirected by a vfprintf hook
    jio_print(s, len);
  }

  // print to log file
-  if (has_log_file()) {
-    int nl0 = _newlines;
-    xmlTextStream::write(s, len);


xmlTextStream::write seems to be unused after this change.

It does seem that way. The outputStream::write method is the function which all subclasses of outputStream implements, so we shouldn't remove this function without removing xmlTextStream. That's probably a separate RFE, and perhaps not desirable as it'd require merging the class into defaultStream.

I'm confused by this part of the change. How can the original code call xmlTextStream::write without an instance of xmlTextStream to apply it to???

defaultStream inherits from xmlTextStream and defaultStream::write exists, so this specifies to call the superclass method, and not its own method. In long form: this->xmlTextStream::write (haven't attempted to compile)

Ah! Thanks - I had missed this code was in defaultStream. It seems a bit klunky to break encapsulation and effectively inline the super write() call so that we can get access to whether a newline was seen - but monitoring _newlines across the write call is at least as bad. I guess this is the problem of trying to have a flushable stream extend a non-flushable superclass - you somehow need to see inside the write to know if there were newlines. The new code at least saves the need for the field.

dholmes-ora

Okay this seems reasonable.

Thanks.

dholmes-ora · 2022-09-28T01:44:15Z

src/hotspot/share/utilities/ostream.cpp

    // print to output stream. It can be redirected by a vfprintf hook
    jio_print(s, len);
  }

  // print to log file
-  if (has_log_file()) {
-    int nl0 = _newlines;
-    xmlTextStream::write(s, len);


Ah! Thanks - I had missed this code was in defaultStream. It seems a bit klunky to break encapsulation and effectively inline the super write() call so that we can get access to whether a newline was seen - but monitoring _newlines across the write call is at least as bad. I guess this is the problem of trying to have a flushable stream extend a non-flushable superclass - you somehow need to see inside the write to know if there were newlines. The new code at least saves the need for the field.

jdksjolen · 2022-09-28T08:32:47Z

/integrate

openjdk · 2022-09-28T08:34:27Z

@jdksjolen
Your change (at version 11977a5) is now ready to be sponsored by a Committer.

coleenp · 2022-09-30T14:43:15Z

/sponsor

openjdk · 2022-09-30T14:45:54Z

Going to push as commit 052a924.
Since your change was applied there have been 139 commits pushed to the master branch:

c2ce43c: 8291021: JFR: Only one finished state in ChunkHeader class
f015733: 8294357: (tz) Update Timezone Data to 2022d
64da862: 8287597: List all preview features on the javadoc PREVIEW page
b4e1e41: 8293000: Review running times of jshell regression tests
6d83482: 8293540: [Metrics] Incorrectly detected resource limits with additional cgroup fs mounts
6974978: 8294521: Parallel: Remove unused field in UpdateDensePrefixAndCompactionTask
81fda1b: 8294569: Remove CardTable::_last_valid_index
7c60e6d: 8293770: RISC-V: Reuse runtime call trampolines
9dce865: 8294115: JNI local refs exceeds capacity warning in NetworkInterface::getAll
b030c7d: 8225235: Unused field defaultIndex in NetworkInterface
... and 129 more: https://git.openjdk.org/jdk/compare/bb422f5c14745bf29bc2cb741f819a17c8400543...master

Your commit was automatically rebased without conflicts.

openjdk · 2022-09-30T14:46:14Z

@coleenp @jdksjolen Pushed as commit 052a924.

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

Reduce size and API scope of outputStream

18847c6

openjdk bot added the rfr Pull request is ready for review label Sep 23, 2022

openjdk bot added the hotspot hotspot-dev@openjdk.org label Sep 23, 2022

robehn approved these changes Sep 26, 2022

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openjdk bot added the ready Pull request is ready to be integrated label Sep 26, 2022

dholmes-ora reviewed Sep 26, 2022

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Remove include

11977a5

dholmes-ora approved these changes Sep 28, 2022

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openjdk bot added the sponsor Pull request is ready to be sponsored label Sep 28, 2022

openjdk bot added the integrated Pull request has been integrated label Sep 30, 2022

openjdk bot closed this Sep 30, 2022

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review sponsor Pull request is ready to be sponsored labels Sep 30, 2022

8294293: Remove unused _width and _newlines field in outputStream #10411

8294293: Remove unused _width and _newlines field in outputStream #10411

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