8367913: LIBDL dependency seems to be not needed for some jdk libs

[MBaesken]

A couple of JDK native libs link to $(LIBDL) , but some do not use symbols from it.

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Issue

• JDK-8367913: LIBDL dependency seems to be not needed for some jdk libs (Bug - P4)

Reviewers

• Christoph Langer (@RealCLanger - Reviewer)
• Martin Doerr (@TheRealMDoerr - Reviewer)
• Alexey Ivanov (@aivanov-jdk - Reviewer)

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8367913: LIBDL dependency seems to be not needed for some jdk libs

Reviewed-by: clanger, mdoerr, aivanov

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At the time when this comment was updated there had been 39 new commits pushed to the master branch:

• 3d4e049: 8367780: Enable UseAPX on Intel CPUs only when both APX_F and APX_NCI_NDD_NF cpuid features are present
• bca1e6e: 8365626: (fs) Improve handling of broken links in Files.isSameFile() (win)
• 695e36b: 8367927: Remove 8043571-related tests from problemlists
• ... and 36 more: https://git.openjdk.org/jdk/compare/a306f88a8456be454f4954c7e4fb8a1273344b5b...master

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[mlbridge]

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[RealCLanger]

Code changes look good but I guess somebody from Oracle has to verify this, whether it does not break unwanted things.

[TheRealMDoerr]

+1

[erikj79]

I have started a verification job with tier1-5.

[MBaesken]

I have started a verification job with tier1-5.

Hi Erik, thanks for checking !

[magicus]

I know libsyslookup is special. It is a dummy library that does not really do anything. I wonder if "pulling in libdl" is one of the things it is there for. Iirc, it is not always used either, so you need to make sure you do testing where it is actually used.

[MBaesken]

I know libsyslookup is special. It is a dummy library that does not really do anything. I wonder if "pulling in libdl" is one of the things it is there for. Iirc, it is not always used either, so you need to make sure you do testing where it is actually used.

Is there some test for this special functionality?

The comments in the C sources
https://github.com/openjdk/jdk/blob/master/src/java.base/share/native/libsyslookup/syslookup.c

do not really help me to understand what functions from libdl we want to bring in this way.

[magicus]

@mcimadamore Can you help us here? libsyslookup has a dependency to libdl, but it is not used. Can we remove that from the linker command line, or would it somehow break libsyslookup? (I have just a very fuzzy idea of the point of this library.) If we try to remove it, what tests do we need to run to make sure we do not break anything?

[prrace]

I have started a verification job with tier1-5.

If that passes, then it is very likely OK.

[MBaesken]

I can bring back the LIBDL dependency of BUILD_LIBSYSLOOKUP if we are unsure about this single removal.

[magicus]

I've pinged Maurizio about libsyslookup; let's hear what he says first.

[erikj79]

I have started a verification job with tier1-5.

Job has completed. There were 2 failures, one had lots of recent history of failing, so seems unrelated. The other was a crash that seemed unusual, but it passed on a rerun. So I think we can say this passed.

[MBaesken]

I have started a verification job with tier1-5.

Job has completed. There were 2 failures, one had lots of recent history of failing, so seems unrelated. The other was a crash that seemed unusual, but it passed on a rerun. So I think we can say this passed.

Thanks for the testing ! So let's wait for some feedback on libsyslookup .