• Jakob Gruber's avatar
    [compiler] Support GetPropertyAccessInfo in a concurrent setting · 1277bb5c
    Jakob Gruber authored
    Until this CL, the JSHeapBroker::GetPropertyAccessInfo (GPAI) process
    was as follows:
    
     1. GPAI is called on the main thread (MT) during the serialization
        phase to create and cache PAIs.
     2. GPAI is called again from the background thread (BT); only cached
        PAIs from step 1 are usable.
    
    As part of concurrent inlining, the goal is to move GPAI fully to the
    background thread. This CL takes a major step in that direction by
    making GPAI itself callable from the BT without resorting solely to PAIs
    that were previously cached on the MT.
    
    There are two main reasons why GPAI previously had to run on the MT:
    
     a) Concurrent access to Maps and other heap objects.
     b) Serialization and creation of ObjectRefs for objects discovered
        during GPAI.
    
    This CL addresses only reason a) and leaves b) for future work. This
    is done by keeping the two-pass approach, s.t. the initial call of
    GPAI on the MT discovers and serializes objects. We then clear all
    cached PAIs. The second call of GPAI on the BT thus runs full logic in a
    concurrent setting.
    
    Once all relevant objects (= maps and prototypes) no longer require
    MT-serialization, reason b) is also addressed and the first pass can be
    removed.
    
    The new logic is implemented behind the runtime flag
    --turbo-concurrent-get-property-access-info (default true), intended
    to be removed in the future.
    
    Bug: v8:7790
    Change-Id: Idbdbfe091d7316529246a686bb6d71c2a0f06f8b
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2817793
    Commit-Queue: Jakob Gruber <jgruber@chromium.org>
    Auto-Submit: Jakob Gruber <jgruber@chromium.org>
    Reviewed-by: 's avatarIgor Sheludko <ishell@chromium.org>
    Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#74120}
    1277bb5c
const-dict-tracking.js 17.7 KB