8340710: Optimize DirectClassBuilder::build #21118

wenshao · 2024-09-22T05:30:43Z

Do some refactoring so that the code can be inlined by the C1/C2 optimizer.

DirectClassBuilder::build codeSize 361 -> 319
DirectCodeBuilder::writeExceptionHandlers codeSize 183 -> 31
BufWriterImpl::writeIndex codeSize 62 -> 37 (forceinline)
BufWriterImpl::writeU2 (forceinline)
Util::writeAttributes codSize 45 -> 40 (forceinline)
Util::writeList codSize 47 -> 42 (forceinline)

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Issue

JDK-8340710: Optimize DirectClassBuilder::build (Sub-task - P4)

Reviewers

Chen Liang (@liach - Reviewer)

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Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/21118/head:pull/21118
$ git checkout pull/21118

Update a local copy of the PR:
$ git checkout pull/21118
$ git pull https://git.openjdk.org/jdk.git pull/21118/head

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Checkout this PR locally:
$ git pr checkout 21118

View PR using the GUI difftool:
$ git pr show -t 21118

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Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/21118.diff

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bridgekeeper · 2024-09-22T05:31:19Z

👋 Welcome back swen! 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 · 2024-09-22T05:31:40Z

@wenshao 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:

8340710: Optimize DirectClassBuilder::build

Reviewed-by: liach

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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.

openjdk · 2024-09-22T05:31:59Z

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

core-libs

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.

src/java.base/share/classes/jdk/internal/classfile/impl/BufWriterImpl.java

liach · 2024-09-22T13:35:08Z

src/java.base/share/classes/jdk/internal/classfile/impl/Util.java

-            writeAttribute(buf, e);
+        int size = list.size();
+        buf.writeU2(size);
+        for (int i = 0; i < size; i++) {


👍 Manual loop unrolling is good for startup

ExE-Boss · 2024-09-22T17:04:24Z

src/java.base/share/classes/jdk/internal/classfile/impl/DirectClassBuilder.java

-        head.writeInt(ClassFile.MAGIC_NUMBER);
-        head.writeU2(minorVersion);
-        head.writeU2(majorVersion);
+        head.writeLong(((long) ClassFile.MAGIC_NUMBER) << 32 | minorVersion << 16 | majorVersion);


minorVersion needs to be cast to a long first, as otherwise when the MSB is set after the shift, then it’ll overwrite the magic number with all 1s.

Suggested change

head.writeLong(((long) ClassFile.MAGIC_NUMBER) << 32 | minorVersion << 16 | majorVersion);

head.writeLong(((long) ClassFile.MAGIC_NUMBER) << 32 | ((long) minorVersion) << 16 | majorVersion);

For clarity, I think using Integer.toUnsignedLong on the shift result is better

If minorVersion > 0xFFFF, the result of using Integer.toUnsignedLong will be wrong. I guess this is the reason why the previous version build failed

Should we add a & 0xFFFF on majorVersion to defend against majorVersion > 0xFFFF too?

liach · 2024-09-23T00:33:26Z

src/java.base/share/classes/jdk/internal/classfile/impl/BufWriterImpl.java

@@ -94,6 +96,10 @@ public ClassFileImpl context() {
        return context;
    }

+    void writeMagic(int minorVersion, int majorVersion) {


Can we call this writeHeader as this writes both the magic and the version?

Now, through the local variable constantPool, codeSize < 325 can be achieved without extracting a separate method.

mlbridge · 2024-09-24T01:15:15Z

Webrevs

01: Full (993fc7c9)
00: Full (2129e0a1)

liach · 2024-09-24T15:35:36Z

src/java.base/share/classes/jdk/internal/classfile/impl/DirectClassBuilder.java

-        head.writeInt(ClassFile.MAGIC_NUMBER);
-        head.writeU2(minorVersion);
-        head.writeU2(majorVersion);
+        head.writeLong((((long) ClassFile.MAGIC_NUMBER) << 32) | ((minorVersion & 0xFFFFL) << 16) | majorVersion);


Suggested change

head.writeLong((((long) ClassFile.MAGIC_NUMBER) << 32) | ((minorVersion & 0xFFFFL) << 16) | majorVersion);

head.writeLong((((long) ClassFile.MAGIC_NUMBER) << 32) | ((minorVersion & 0xFFFFL) << 16) | (majorVersion & 0xFFFFL));

openjdk · 2024-09-24T16:01:04Z

@wenshao 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 optim_classfile_build_202409
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

…uild_202409 # Conflicts: # src/java.base/share/classes/jdk/internal/classfile/impl/Util.java

wenshao · 2024-09-25T02:34:23Z

/integrate

openjdk · 2024-09-25T02:35:42Z

Going to push as commit 2e0554a.
Since your change was applied there have been 9 commits pushed to the master branch:

2d38af6: 8340587: Optimize StackMapGenerator$Frame::checkAssignableTo
9bcc7b6: 8340708: Optimize StackMapGenerator::processMethod
a37bb2e: 8340643: RISC-V: Small refactoring for sub/subw macro-assembler routines
c0fcb25: 8340717: Remove unused function declarations from java.c/java.h of the launcher
0b8c9f6: 8338525: Leading and trailing code blocks by indentation
b639661: 8340804: doc/building.md update Xcode instructions to note that full install is required
e3d80f1: 8340670: Policy.UNSUPPORTED_EMPTY_COLLECTION.isReadOnly does not return true
8c08c43: 8340433: Open source closed choice tests optimization algorithm：tableSizeFor #3
90c2c0b: 8340143: Open source several Java2D rendering loop tests.

Your commit was automatically rebased without conflicts.

openjdk · 2024-09-25T02:35:49Z

@wenshao Pushed as commit 2e0554a.

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

optimize DirectClassBuilder::build

211aa8a

openjdk bot added the core-libs [email protected] label Sep 22, 2024

wenshao marked this pull request as draft September 22, 2024 09:11

wenshao added 4 commits September 22, 2024 17:21

optimize for writeExceptionHandlers for C1

417aeab

force inline invalidIndex

2d6e224

force inline writeU2

929e5bf

force inline Util::writeAttributes & Util::writeList

ae195bc

wenshao marked this pull request as ready for review September 22, 2024 11:12

liach reviewed Sep 22, 2024

View reviewed changes

suggestion from @liach

59e6c69

ExE-Boss reviewed Sep 22, 2024

View reviewed changes

fix write header

590d4b8

liach reviewed Sep 23, 2024

View reviewed changes

inline writeLong & local constantPool

2129e0a

wenshao requested a review from liach September 23, 2024 14:06

wenshao changed the title ~~Optimize DirectClassBuilder::build~~ 8340710: Optimize DirectClassBuilder::build Sep 24, 2024

openjdk bot added the rfr Pull request is ready for review label Sep 24, 2024

liach reviewed Sep 24, 2024

View reviewed changes

suggestion from @liach

f144a0a

openjdk bot added the merge-conflict Pull request has merge conflict with target branch label Sep 24, 2024

Merge remote-tracking branch 'upstream/master' into optim_classfile_b…

993fc7c

…uild_202409 # Conflicts: # src/java.base/share/classes/jdk/internal/classfile/impl/Util.java

openjdk bot removed the merge-conflict Pull request has merge conflict with target branch label Sep 24, 2024

liach approved these changes Sep 24, 2024

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openjdk bot added the ready Pull request is ready to be integrated label Sep 24, 2024

openjdk bot added the integrated Pull request has been integrated label Sep 25, 2024

openjdk bot closed this Sep 25, 2024

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Sep 25, 2024

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8340710: Optimize DirectClassBuilder::build #21118

8340710: Optimize DirectClassBuilder::build #21118

wenshao commented Sep 22, 2024 •

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wenshao commented Sep 25, 2024

openjdk bot commented Sep 25, 2024

openjdk bot commented Sep 25, 2024

	head.writeLong(((long) ClassFile.MAGIC_NUMBER) << 32 \| minorVersion << 16 \| majorVersion);
	head.writeLong(((long) ClassFile.MAGIC_NUMBER) << 32 \| ((long) minorVersion) << 16 \| majorVersion);

	head.writeLong((((long) ClassFile.MAGIC_NUMBER) << 32) \| ((minorVersion & 0xFFFFL) << 16) \| majorVersion);
	head.writeLong((((long) ClassFile.MAGIC_NUMBER) << 32) \| ((minorVersion & 0xFFFFL) << 16) \| (majorVersion & 0xFFFFL));

8340710: Optimize DirectClassBuilder::build #21118

8340710: Optimize DirectClassBuilder::build #21118

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wenshao commented Sep 22, 2024 • edited by openjdk bot Loading

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