8383460: Replace "sharing" in VM version string with "aot" information

[iklam]

[1] When using the new AOT workflow, the word "sharing" is replaced with "aot training", "aot assembly", or "aot production" as appropriate.
[2] Changed Abstract_VM_Version::vm_info_string() to return a c-heap allocated string. The caller should free it. The old way of enumerating every single possibility is not scalable.

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Issue

• JDK-8383460: Replace "sharing" in VM version string with "aot" information (Enhancement - P4)

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Ashutosh Mehra (@ashu-mehra - Reviewer)

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[openjdk]

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8383460: Replace "sharing" in VM version string with "aot" information

Reviewed-by: kvn, asmehra

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At the time when this comment was updated there had been 83 new commits pushed to the master branch:

• 660dd42: 8391041: RISC-V: Fix out-of-bounds read in string_indexof_char intrinsic
• f40a2c3: 8241634: Support execution of threads as virtual in LingeredApp
• f06fb73: 8382276: Update nsk/jdwp to use ThreadWrapper
• ... and 80 more: https://git.openjdk.org/jdk/compare/9a601b46b2f2bc68f4de42fe2c00b77da55246b0...master

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[mlbridge]

Webrevs

• 00: Full (07c3a59d)

[vnkozlov]

It is annoying to remember to use FREE_C_HEAP_ARRAY(). Can we allocate version string on ResourceArea and use ResourceMark?

[vnkozlov]

On other hand you may need to add as many ResourceMark as FREE_C_HEAP_ARRAY.
I will leave it to runtime group reviewer to decide what is the best.

[iklam]

On other hand you may need to add as many ResourceMark as FREE_C_HEAP_ARRAY. I will leave it to runtime group reviewer to decide what is the best.

Abstract_VM_Version::vm_info_string() is called very early during VM bootstrap and ResourceMark doesn't work yet (Thread::_current is not yet initialized).

We only call this function in a small number of places so having to free explicitly doesn't seem to be too bad.

[vnkozlov]

Thank you for explanation. Changes look good then.

[ashu-mehra]

lgtm

[ashu-mehra]

Are we sure the pointer is not cached in some global variable/structure by any of the callee to which vm_info_str is passed?

We only call this function in a small number of places so having to free explicitly doesn't seem to be too bad.

I don't mind this. If any one feels strongly about this, I guess another option is to use RAII pattern, like:

class VMInfoString {
  const char* str;
  VMInfoString() {
    str = Abstract_VM_Version::vm_info_string();
  }
  
  ~VMInfoString() {
    FREE_C_HEAP_ARRAY(str);
    str = nullptr;
  }
}

[iklam]

Are we sure the pointer is not cached in some global variable/structure by any of the callee to which vm_info_str is passed?

All the calls of VM_Version::vm_info_string() have been touched in this PR. The only ones that save the value is to set the "java.vm.info" property -- there are 3 cases that all have different paths (what a mess!) but in each case the value is copied and, if necessary, the old value is freed inside PathString::set_value()

[ashu-mehra]

All the calls of VM_Version::vm_info_string() have been touched in this PR. The only ones that save the value is to set the "java.vm.info" property -- there are 3 cases that all have different paths (what a mess!) but in each case the value is copied and, if necessary, the old value is freed inside PathString::set_value()

Thanks for adding this info. I have no more comments, and the code changes look fine.

[iklam]

Thanks @vnkozlov @ashu-mehra for the review
/integrate

[openjdk]

Going to push as commit 30df8a5.
Since your change was applied there have been 100 commits pushed to the master branch:

• 5b96789: 8390906: Allow to collect per-test code coverage information
• 7a6258b: 8324871: Several container tests fail with java.io.tmpdir directory does not exist on linux-aarch64 cgroups-v2
• cd63012: 8388530: JDI and JDWP spec cleanup to get rid of "if preview is enabled"
• ... and 97 more: https://git.openjdk.org/jdk/compare/9a601b46b2f2bc68f4de42fe2c00b77da55246b0...master

Your commit was automatically rebased without conflicts.

[openjdk]

@iklam Pushed as commit 30df8a5.

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