• Jakob Gruber's avatar
    Reland "[compiler] Consider IsPendingAllocation in Ref construction" · 4683d6fe
    Jakob Gruber authored
    This is a reland of 5f0ac36c
    
    Fixes Ref construction failures in:
    - MapRef::instance_descriptors
    - NativeContext reads (see also crrev.com/c/2891575)
    
    Original change's description:
    > [compiler] Consider IsPendingAllocation in Ref construction
    >
    > The logic in JSHeapBroker::TryGetOrCreateData assumes that parts
    > of the object are safe to read. In particular, the instance type
    > must be readable for the chain of `Is##Name()` type checks.
    >
    > This is guaranteed if
    >
    >  - a global memory fence happened after object initialization and
    >    prior to the read by the compiler; or
    >  - the object was published through a release store and read through
    >    an acquire read.
    >
    > The former is protected by the new call to ObjectMayBeUninitialized
    > (which internally calls IsPendingAllocation) in TryGetOrCreateData.
    >
    > The latter must be marked explicitly by calling the new
    > MakeRefAssumeMemoryFence variant.
    >
    > Note that support in this CL is expected to be incomplete and will
    > have to be extended in the future as more cases show up in which
    > MakeRef calls must be converted to MakeRefAssumeMemoryFence or to
    > TryMakeRef.
    >
    > Bug: v8:7790,v8:11711
    > Change-Id: Ic2f7d9fc46e4bfc3f6bbe42816f73fc5ec174337
    > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2874663
    > Commit-Queue: Jakob Gruber <jgruber@chromium.org>
    > Reviewed-by: Georg Neis <neis@chromium.org>
    > Cr-Commit-Position: refs/heads/master@{#74474}
    
    Bug: v8:7790,v8:11711,chromium:1207680,chromium:1207679
    Change-Id: Ib3dbf59909e6982a3230dd6a67c9fb7d6ffb9ab4
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2886861Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
    Commit-Queue: Jakob Gruber <jgruber@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#74587}
    4683d6fe
regress-1207679.js 487 Bytes