RFR: 8327701: Remove the xlc toolchain [v2]

[Joachim Kern]

On Fri, 8 Mar 2024 15:48:08 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> As of [JDK-8325880](https://bugs.openjdk.org/browse/JDK-8325880), building the JDK requires version 17 of IBM Open XL C/C++ (xlc). This is in effect clang by another name, and it uses the clang toolchain in the JDK build. Thus the old xlc toolchain is no longer supported, and should be removed.
>
> Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert SEARCH_PATH changes

Changes requested by jkern (Author).

doc/building.html line 679:

> 677: <h3 id="ibm-open-xl-cc">IBM Open XL C/C++</h3>
> 678: <p>The minimum accepted version of Open XL is 17.1.1.4. This is in
> 679: essence clang 13, and will be treated as such by the OpenJDK build

It is clang 15 not 13. Clang 13 was in 17.1.0

doc/building.md line 493:

> 491: 
> 492: The minimum accepted version of Open XL is 17.1.1.4. This is in essence clang
> 493: 13, and will be treated as such by the OpenJDK build system.

clang 15 not 13

make/autoconf/toolchain.m4 line 285:

> 283:       XLC_TEST_PATH=${TOOLCHAIN_PATH}/
> 284:     fi
> 285:     if test "x$TOOLCHAIN_TYPE" = xclang; then

Why did you also remove the test for the clang compiler? Ah I see, you moved the clang compiler check down below

make/autoconf/toolchain.m4 line 409:

> 407:     #    Target: powerpc-ibm-aix7.2.0.0
> 408:     #    Thread model: posix
> 409:     #    InstalledDir: /opt/IBM/openxlC/17.1.0/bin

Please correct:
IBM Open XL C/C++ for AIX 17.1.**1** (xxxxxxxxxxxxxxx), clang version 1**5**.0.0
    #    Target: **powerpc-ibm-aix7.2.**5**.7**
    #    Thread model: posix
    #    InstalledDir: /opt/IBM/openxlC/17.1.**1**/bin

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PR Review: https://git.openjdk.org/jdk/pull/18172#pullrequestreview-1927198641
PR Review Comment: https://git.openjdk.org/jdk/pull/18172#discussion_r1519321337
PR Review Comment: https://git.openjdk.org/jdk/pull/18172#discussion_r1519321980
PR Review Comment: https://git.openjdk.org/jdk/pull/18172#discussion_r1519358938
PR Review Comment: https://git.openjdk.org/jdk/pull/18172#discussion_r1519365934