JDK-8304884: Update Bytecodes data to be mostly compile time constants by jcking · Pull Request #13179 · openjdk/jdk

jcking · 2023-03-24T16:14:50Z

Change uses a few tricks to make most of the data in Bytecodes compile time constant, avoiding the overhead during VM initialization. Bytecodes:_flags likely can be made compile time constant as well using constexpr tricks, but that is out of scope for this specific PR.

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Change must not contain extraneous whitespace
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Issue

JDK-8304884: Update Bytecodes data to be mostly compile time constants

Reviewers

Coleen Phillimore (@coleenp - Reviewer)
@Jekyle (no known openjdk.org user name / role) ⚠️ Review applies to cf71fcdd
David Holmes (@dholmes-ora - Reviewer)

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/13179/head:pull/13179
$ git checkout pull/13179

Update a local copy of the PR:
$ git checkout pull/13179
$ git pull https://git.openjdk.org/jdk.git pull/13179/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 13179

View PR using the GUI difftool:
$ git pr show -t 13179

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/13179.diff

Signed-off-by: Justin King <jcking@google.com>

bridgekeeper · 2023-03-24T16:15:47Z

👋 Welcome back jcking! 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 · 2023-03-24T16:19:16Z

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

hotspot-runtime

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 · 2023-03-24T16:22:49Z

Webrevs

TheShermanTanker · 2023-03-24T17:17:53Z

Not a review, but I want to point out that Bytecodes::_flags is declared as a jchar and defined as an unsigned short, might probably be helpful and less confusing to make it an unsigned short in both places. No comment on the other changes

Signed-off-by: Justin King <jcking@google.com>

jcking · 2023-03-24T17:54:57Z

Not a review, but I want to point out that Bytecodes::_flags is declared as a jchar and defined as an unsigned short, might probably be helpful and less confusing to make it an unsigned short in both places. No comment on the other changes

Switched to jcharin both places.

coleenp

This seems reasonable. Some suggested changes.

src/hotspot/share/interpreter/bytecodes.cpp

coleenp · 2023-03-24T18:49:25Z

src/hotspot/share/interpreter/bytecodes.cpp

+#undef BYTECODE_JAVA_CODE
+};
+
+jchar Bytecodes::_flags[(1<<BitsPerByte)*2];


Why is this not _flags[Bytecodes::number_of_codes] ?

It should probably be Bytecodes::number_of_codes * 2. Two entry per byte-code. One for the normal format and one for wide. Wasn't sure if it was safe or some code was relying on there being exactly 512 entries even if bytecode count is less than 256.

When this was put in (JDK-6939207) the flags were arranged so that the two forms were at index N and N+256 rather than index N and N+number_of_codes. That seems to remain the case today - just grep for 1<<BitsPerByte

Signed-off-by: Justin King <jcking@google.com>

jcking · 2023-03-24T22:57:57Z

/reviewers 2

openjdk · 2023-03-24T22:59:00Z

@jcking
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 1 Reviewer, 1 Author).

dholmes-ora

Changes seem okay - unfortunately a lot of noise in the PR diff that obscures actual changes.

A couple of queries.

Thanks.

dholmes-ora · 2023-03-27T01:53:13Z

src/hotspot/share/interpreter/bytecodes.cpp

+  }
+};
+
+#define STRING_SIZE(string) StringLiteralSize::invoke(string)


Can't you simply use:

#define STRING_SIZE(string) (sizeof(string) - 1)

?

No, due to nullptr for the wide_format. That was my first instinct as well, then I saw nullptr.

Signed-off-by: Justin King <jcking@google.com>

coleenp

Thanks, looks good.

coleenp · 2023-03-27T14:52:16Z

src/hotspot/share/interpreter/bytecodes.cpp

+#undef BYTECODE_JAVA_CODE
+};
+
+jchar Bytecodes::_flags[(1<<BitsPerByte)*2];


openjdk · 2023-03-27T14:54:51Z

@jcking 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:

8304884: Update Bytecodes data to be mostly compile time constants

Reviewed-by: coleenp, 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 31 new commits pushed to the master branch:

4f625c0: 8304543: Modernize debugging jvm args in test/hotspot/jtreg/vmTestbase/nsk/jdi/Argument/value/value004.java
426025a: 8303526: Changing "arbitrary" Name.compareTo() ordering breaks the regression suite
6aec6f3: 8304931: vm/concepts/methods/methods001/methods00101m1/methods00101m1 failures with already pending exception
63ce88b: 8304147: JVM crash during shutdown when dumping dynamic archive
554bccf: 8304448: Kitchensink failed: assert(!thread->is_in_any_VTMS_transition()) failed: class prepare events are not allowed in any VTMS transition
3b88b2a: 8304761: Update IANA Language Subtag Registry to Version 2023-03-22
f8e8fc7: 8177352: Calendar.getDisplayName(s) in non-lenient mode inconsistent, does not match spec
14b970d: 8296656: java.lang.NoClassDefFoundError exception on running fully legitimate code
80e2d52: 8302558: Editable JComboBox's popup blocks user from seeing characters in Aqua look and feel
6c3b10f: 8303485: Replacing os.name for operating system customization
... and 21 more: https://git.openjdk.org/jdk/compare/f96aee74010476a850175f7012c196e40a31c188...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.

jcking · 2023-03-28T14:15:21Z

/integrate

openjdk · 2023-03-28T14:17:13Z

Going to push as commit 32ef452.
Since your change was applied there have been 39 commits pushed to the master branch:

927e674: 8300977: Retire java.io.ExpiringCache
c90699e: 8304989: unnecessary dash in @param gives double-dash in docs
395a4ce: 8304591: (fs) UnixPath.stringValue need not be volatile
60640a2: 8300979: Lazily initialize (byte, char)arr in java.io.DataInputStream
cddaf68: 8304962: sun/net/www/http/KeepAliveCache/B5045306.java: java.lang.RuntimeException: Failed: Initial Keep Alive Connection is not being reused
a06f461: 8303214: Typo in java.util.Collections#synchronizedNavigableMap javadoc
7987ad4: 8304412: Serial: Refactor old generation cards update after Full GC
3c4cd50: 8304963: HttpServer closes connection after processing HEAD after JDK-7026262
4f625c0: 8304543: Modernize debugging jvm args in test/hotspot/jtreg/vmTestbase/nsk/jdi/Argument/value/value004.java
426025a: 8303526: Changing "arbitrary" Name.compareTo() ordering breaks the regression suite
... and 29 more: https://git.openjdk.org/jdk/compare/f96aee74010476a850175f7012c196e40a31c188...master

Your commit was automatically rebased without conflicts.

openjdk · 2023-03-28T14:17:31Z

@jcking Pushed as commit 32ef452.

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

jcking added 2 commits March 24, 2023 09:08

Statically initialize parts of Bytecodes

f1517ae

Signed-off-by: Justin King <jcking@google.com>

Update spacing

87cf87f

Signed-off-by: Justin King <jcking@google.com>

openjdk bot added the rfr Pull request is ready for review label Mar 24, 2023

openjdk bot added the hotspot-runtime hotspot-runtime-dev@openjdk.org label Mar 24, 2023

Update definition to match declaration

d1a8dbd

Signed-off-by: Justin King <jcking@google.com>

coleenp suggested changes Mar 24, 2023

View reviewed changes

jcking added 2 commits March 24, 2023 15:54

Fix compiler warnings

6cdf64e

Signed-off-by: Justin King <jcking@google.com>

Replace XX with def and add _DO suffix

cf71fcd

Signed-off-by: Justin King <jcking@google.com>

Jekyle approved these changes Mar 25, 2023

View reviewed changes

dholmes-ora approved these changes Mar 27, 2023

View reviewed changes

Update indentation

739689d

Signed-off-by: Justin King <jcking@google.com>

coleenp approved these changes Mar 27, 2023

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label Mar 27, 2023

dholmes-ora approved these changes Mar 28, 2023

View reviewed changes

openjdk bot added the integrated Pull request has been integrated label Mar 28, 2023

openjdk bot closed this Mar 28, 2023

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Mar 28, 2023

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