Remove some methods from recognized methods

[knn-k]

These methods no longer exist in the Java class library.

• sun/nio/cs/ISO_8859_1$Decoder.decodeISO8859_1()
• sun/nio/cs/UTF_8$Encoder.encodeUTF_8()
• sun/nio/cs/ext/SBCS_Encoder.encodeSBCS()
• sun/nio/cs/ext/SBCS_Decoder.decodeSBCS()

[knn-k]

Jenkins test sanity amac jdk17 depends eclipse-omr/omr#7527

[knn-k]

I searched for the methods in the following JCL code, and made sure the methods are not defined there.
In addition, there are no "sun.nio" classes in https://github.com/eclipse-openj9/openj9/tree/master/jcl/src/java.base/share/classes.
IBM SDK Java 8 does not have these methods, either.

Java 8:

• https://github.com/ibmruntimes/openj9-openjdk-jdk8/blob/openj9/jdk/src/share/classes/sun/nio/cs/ISO_8859_1.java
• https://github.com/ibmruntimes/openj9-openjdk-jdk8/blob/openj9/jdk/src/share/classes/sun/nio/cs/UTF_8.java

Java 11:

• https://github.com/ibmruntimes/openj9-openjdk-jdk11/blob/openj9/src/java.base/share/classes/sun/nio/cs/ISO_8859_1.java
• https://github.com/ibmruntimes/openj9-openjdk-jdk11/blob/openj9/src/java.base/share/classes/sun/nio/cs/UTF_8.java

Java 17:

• https://github.com/ibmruntimes/openj9-openjdk-jdk17/blob/openj9/src/java.base/share/classes/sun/nio/cs/ISO_8859_1.java
• https://github.com/ibmruntimes/openj9-openjdk-jdk17/blob/openj9/src/java.base/share/classes/sun/nio/cs/UTF_8.java

Java 21:

• https://github.com/ibmruntimes/openj9-openjdk-jdk21/blob/openj9/src/java.base/share/classes/sun/nio/cs/ISO_8859_1.java
• https://github.com/ibmruntimes/openj9-openjdk-jdk21/blob/openj9/src/java.base/share/classes/sun/nio/cs/UTF_8.java

[hzongaro]

Note that these enumerated constants are used in EncodeMethods which is in turn used to identify recognized methods in:

• sun/nio/cs/UTF_8$Decoder,sun/nio/cs/UTF_8$Encoder, sun/nio/cs/UTF16_Encoder;
• sun/nio/cs/US_ASCII$Encoder, sun/nio/cs/US_ASCII$Decoder, sun/nio/cs/ext/SBCS_Encoder, sun/nio/cs/ext/SBCS_Decoder; and
• sun/nio/cs/ISO_8859_1$Encoder, sun/nio/cs/ISO_8859_1$Decoder

I don't think these methods exist in any of those classes.

I think this change looks good, but I'm just trying to look into the history to understand when these methods disappeared.

[knn-k]

• sun/nio/cs/ISO_8859_1$Decoder.decodeISO8859_1(): Removed by this PR
• sun/nio/cs/ISO_8859_1$Encoder.encodeArrayLoop(), sun/nio/cs/ISO_8859_1$Encoder.encodeISOArray(): Used in Java 8+. See https://github.com/ibmruntimes/openj9-openjdk-jdk11/blob/openj9/src/java.base/share/classes/sun/nio/cs/ISO_8859_1.java for example.
• sun/nio/cs/US_ASCII$Encoder.encodeASCII(), sun/nio/cs/US_ASCII$Decoder.decodeASCII(): Used in Java 8 and 11. See https://github.com/ibmruntimes/openj9-openjdk-jdk11/blob/openj9/src/java.base/share/classes/sun/nio/cs/US_ASCII.java
• sun/nio/cs/UTF_8$Decoder.decodeUTF_8(): Not found in Semeru Runtimes, but IBM SDK for Java 8 has this method.
• sun/nio/cs/UTF_8$Encoder.encodeUTF_8(): Removed by this PR
• sun/nio/cs/UTF16_Encoder.encodeUTF16Big(), sun/nio/cs/UTF16_Encoder.encodeUTF16Little(): Not found
• sun/nio/cs/ext/SBCS_Encoder.encodeSBCS(), sun/nio/cs/ext/SBCS_Decoder.decodeSBCS(): Not found. They might be specific to the Z platform. See the comment "only z" in https://github.com/eclipse-omr/omr/blob/90923011f5c8f9f86c6a633ed3454380506ecfdf/compiler/optimizer/ValuePropagationCommon.cpp#L2607-L2625

[knn-k]

Removing sun/nio/cs/UTF_16$Encoder.encodeUTF16Big() and encodeUTF_16Little() will be a big change, removing helper functions for p and x. I would like to do that in separate pull requests after making sure it is safe to remove them.

I wonder if someone working on Z can look at sun/nio/cs/ext/SBCS_*.

[knn-k]

IBM SDK Java 8 has the class sun/nio/cs/ext/SBCS_Encoder, but it does not have the encodeSBCS() method. It is the same for the decodeSBCS() method in the SBCS_Decoder class.

[knn-k]

I updated the commit to additionally remove SBCS_Encoder.encodeSBCS() and SBCS_Decoder.decodeSBCS().

[knn-k]

Jenkins test sanity zlinux jdk17 depends eclipse-omr/omr#7527

[knn-k]

I opened separate pull requests for sun/nio/cs/UTF16_Encoder methods:

• Stop recognizing UTF16_Encoder.encodeUTF16 methods #20613
• Stop recognizing UTF16_Encoder.encodeUTF16 methods eclipse-omr/omr#7548

[knn-k]

Rebased to resolve merge conflicts.

[knn-k]

Jenkins test sanity xlinux,zlinux jdk17 depends eclipse-omr/omr#7527

Rebased to resolve merge conflicts.

[r30shah]

Hi @knn-k , I am looking at the class files that is shipped with the IBM SDK 8 on z/OS to go through the methods that you are removing in this PR.

Commenting about following 3 recognized methods referencing from changes in runtime/compiler/codegen/J9RecognizedMethodsEnum.hpp which all exists in the IBM SDK8 on z/OS.

1. sun.nio.cs.ISO_8859_1$Decoder.decodeISO8859_1(byte[], int, int, char[], int);
2. sun.nio.cs.ext.SBCS_Encoder.encodeSBCS(char[], int, int, byte[], int, byte[]);
3. sun.nio.cs.ext.SBCS_Decoder.decodeSBCS(byte[], int, int, char[], int, char[]);
4. sun.nio.cs.UTF_8.$Encoder.encodeUTF_8(char[], int, int, byte[], int);

These changes in the JIT recognize methods provides vital performance related to code pages conversion and is important on z/OS that we should not remove.

[knn-k]

@r30shah Thank you for checking IBM SDK 8 for z/OS. I am cancelling this PR.

I checked IBM SDK 8 for other platforms as well as Semeru Runtimes 8-21. I didn't know IBM SDK 8 for z/OS had its own classes and methods.

[pshipton]

Maybe it would be worth adding comments for these methods to explain where they are used.

[knn-k]

I opened PR #20864 for adding comments to the encoding/decoding methods.