• Seth Brenith's avatar
    Revert "Remove 'length' field from ScopeInfo" · 6c922e39
    Seth Brenith authored
    This reverts commit f731e13f.
    
    Reason for revert: perf regressions, chromium:1179757
    
    Original change's description:
    > Remove 'length' field from ScopeInfo
    >
    > ScopeInfo has a vestigial 'length' field from when it used to be a
    > FixedArray. This change removes that field, which saves some memory.
    >
    > More specifically:
    >
    > - Make ScopeInfo inherit from HeapObject, not FixedArrayBase which
    >   supplied the 'length' field.
    > - Privatize the FixedArray-style functions that provide access to
    >   ScopeInfo fields by index, and move them from scope-info-inl.h to
    >   scope-info.cc. Those functions are still used pretty heavily during
    >   initialization (ScopeInfo::Create, etc.), but at least we can avoid
    >   presenting them to the rest of the world.
    > - Change FactoryBase::NewScopeInfo to allocate the updated object shape.
    >   It maintains the existing behavior of filling the newly-allocated
    >   object with undefined, even though that's not a valid ScopeInfo and
    >   further initialization is required.
    > - Move part of AccessorAssembler::ScriptContextTableLookup into a new
    >   Torque macro, because it used to rely on casting ScopeInfo to
    >   FixedArrayBase.
    > - In V8HeapExplorer::AddEntry, don't claim that ScopeInfo objects are
    >   arrays. I think it makes more sense to list them under "(system)" in
    >   the dev tools, like most other V8 internal types.
    >
    > Bug: v8:8952
    > Change-Id: I8278e3a90027d4409f0d268da0fe7080754c6b8c
    > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2601880
    > Reviewed-by: Toon Verwaest <verwaest@chromium.org>
    > Reviewed-by: Peter Marshall <petermarshall@chromium.org>
    > Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
    > Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
    > Reviewed-by: Mythri Alle <mythria@chromium.org>
    > Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
    > Cr-Commit-Position: refs/heads/master@{#72830}
    
    Bug: v8:8952
    Change-Id: I00a69da79e5ac6aaae4436a41ce773ae014cc775
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2706086
    Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
    Auto-Submit: Seth Brenith <seth.brenith@microsoft.com>
    Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
    Reviewed-by: 's avatarNico Hartmann <nicohartmann@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#72855}
    6c922e39
accessor-assembler.cc 172 KB