RFR: 8339299: C1 will miss type profile when inline final method [v4]

[Leonid Mesnik]

On Mon, 9 Sep 2024 07:31:39 GMT, kuaiwei <duke at openjdk.org> wrote:

>> I found sometimes C1 will miss type profile and I tried to write a test to demonstrate it.
>> It will happen with these conditions
>> 1 It's a virtual call and the callee is a final method. So c1 will think it's static bound.
>> 2 The interpreter never touch the callsite, so interpreter does not add type profile.
>> 3 In c1 compilation, it will be inlined based on CHA.
>> 4 In c2 compilation, the CHA is broken, but type profile is missing, so c2 can not inline it.
>
> kuaiwei has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Merge branch 'master' of https://github.com/openjdk/jdk into c1_cha_type_profile
>  - Simplify should_profile_receiver_type
>  - Modify test case to use whitebox api
>  - 8339299: C1 will miss type profile when inline final method

Changes requested by lmesnik (Reviewer).

test/hotspot/jtreg/compiler/cha/TypeProfileFinalMethod.java line 46:

> 44: public class TypeProfileFinalMethod {
> 45:     public static void main(String[] args) throws Exception {
> 46:        ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(

The createLimitedTestJavaProcessBuilder ignores any other VM flags. This mode should be used only of test too specific. 
 However, 
 * @requires (vm.opt.TieredStoAtLevel == null | vm.opt.TieredStopAtLevel == 4)
means that we are going to run test with mostly any GC/Runtime and C2 stress options flags. (No C1-only)
So it is needed to use createLimitedTestJavaProcessBuilder to accept all VM flags.
You don't neet to test any additional VM flags until you have a reasons to suppose that something might fails. 
Just use 'createTestJavaProcessBuilder' insted.
If you think that test shouldn't accept any addtional vm flags, use
@requires vm.flagless
instead of
 @requires (vm.opt.TieredStoAtLevel == null | vm.opt.TieredStopAtLevel == 4)
So test is executed only once and don't run if it is gong to ignore flags.

-------------

PR Review: https://git.openjdk.org/jdk/pull/20786#pullrequestreview-2290244295
PR Review Comment: https://git.openjdk.org/jdk/pull/20786#discussion_r1750466093