• Georgia Kouveli's avatar
    [instruction-scheduler] Add a RandomNumberGenerator to InstructionScheduler · 6be9ac9d
    Georgia Kouveli authored
    When running the tests with --turbo-stress-instruction-scheduling, there are
    crashes in the cases where there is no isolate, since we used the random
    generator from the isolate. This change introduces a RandomNumberGenerator to
    the instruction scheduler instead.
    
    We use the value from --random-seed for seeding the random number generator.
    We don't treat a zero value specially, as the feature is meant to be used with
    the test system which always sets a random seed and doesn't rely on default
    behaviour. This also means that the instruction scheduler will always produce
    the same result for the same input within the same run, which fixes another
    issue with the x64 jump optimisation: when that optimisation is enabled, the
    backend is ran twice, and previously it was producing a different schedule
    each time, thus collecting incorrect jump information.
    
    Bug: v8:9884
    Change-Id: I00394a7e50d0c502254b18490ebaf28a38d8f819
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1895555Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
    Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
    Cr-Commit-Position: refs/heads/master@{#64769}
    6be9ac9d
instruction-scheduler.h 9.25 KB