RFR: 8331185: Enable compiler memory limits in debug builds [v11]

[Vladimir Kozlov]

On Tue, 7 May 2024 04:27:12 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> See [1] for previous discussions.
>> 
>> We'd like to introduce a default memory limit for compilations in debug builds. That way, we can catch pathological compiler errors that have an unreasonably high per-compilation memory footprint early during testing.
>> 
>> The default limit affects all compilations, unless the method is subject to a memory limit set from command line. Meaning, `-XX:CompileCommand=MemLimit,...` overrules the default.
>> 
>> Examples:
>> 
>> This lowers the memlimit for j.l.String methods - all methods will have the default 1GB limit in a debug JVM. Only j.l.String will run with a 100M limit: `-XX:CompileCommand=MemLimit,java.lang.String::*,100m`
>> 
>> This disables the default memlimit globally: `-XX:CompileCommand=MemLimit,*.*,0`
>> 
>> 
>> ---
>> 
>> The patch:
>> 
>> 1) adds a debug-only default memory limit of **1GB** (as proposed by @vnkozlov). The limit action is "crash", meaning we will assert.
>> 2) To test the mechanics, we now print out the memory limit for each compilation in the compilation cost record.
>> 3) Adapted and extended tests
>> 
>> I also fixed up some copyrights that I overlooked last year when adding the compiler memory statistics this patch builds atop of.
>> 
>> 
>> Tested:
>> 
>> - manually on Mac m1 (debug and release)
>> - GHAs are running
>> - but Oracle will do more testing before this goes in
>> 
>> [1] https://mail.openjdk.org/pipermail/hotspot-compiler-dev/2024-April/074787.html
>
> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 19 commits:
> 
>  - remove debug output
>  - Merge branch 'master' into compiler-default-limit
>  - fix compiler.c2.TestFindNode again
>  - merge master and fix conflicts
>  - Remove unused variable
>  - Remove accidental change to TestDeadPhiMergeMemLoop.java
>  - fix copyrights
>  - fix copyrights
>  - another fix
>  - fix accidental slip in of another test name
>  - ... and 9 more: https://git.openjdk.org/jdk/compare/f308e107...61dc5952

Looks good.

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Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18969#pullrequestreview-2043822389