RFR: 8343883: Cannot resolve user specified toolchain-path for lld after JDK-8338304 [v2]

[Magnus Ihse Bursie]

On Tue, 12 Nov 2024 15:38:41 GMT, SendaoYan <syan at openjdk.org> wrote:

>> Hi all,
>> After [JDK-8338304](https://bugs.openjdk.org/browse/JDK-8338304), below configure command will generate failure `error: Could not find required tool for LLD`. The lld linker located in path which config with option `--with-toolchain-path`, but the check `UTIL_REQUIRE_PROGS(LLD, lld)` introduced by [JDK-8338304](https://bugs.openjdk.org/browse/JDK-8338304) was unable to find the lld. This PR add the condition to deal with user specidied `--with-toolchain-path` to find the correct lld fullpath. The change has beeen verified locally, trivial fix, the risk is low.
>> 
>> 
>> bash configure --with-jobs=128 --with-debug-level=release --enable-unlimited-crypto --with-jvm-variants=server --with-version-opt=f4008968 --with-zlib=system --with-toolchain-type=clang --with-toolchain-path=/home/yansendao/software/acc/x86_64/bin
>
> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   lookup $TOOLCHAIN_PATH:$PATH

make/autoconf/flags-ldflags.m4 line 77:

> 75:       BASIC_LDFLAGS="-fuse-ld=lld -Wl,--exclude-libs,ALL"
> 76:       if test "x$CXX_IS_USER_SUPPLIED" = xfalse && test "x$CC_IS_USER_SUPPLIED" = xfalse; then
> 77:         UTIL_REQUIRE_PROGS(LLD, lld, $TOOLCHAIN_PATH:$PATH)

Actually, I am not 100% sure that this will work if $TOOLCHAIN_PATH is empty. You need to check that. If not, this should probably be fixed in UTIL_CHECK_PROGS instead to allow for that, since this is a more elegant solution if empty path values are allowed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21999#discussion_r1838379285