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src: fix pointer compression build #50680

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Closed

src: fix pointer compression build #50680

wants to merge 2 commits into from

Commits on Nov 16, 2023

  1. deps: V8: cherry-pick 475c8cdf9a95 

    Original commit message:

    [ptr-compr] Fix multi-cage mode

    This CL introduces PtrComprCageAccessScope which sets/restores current
    thread's pointer compression cage base values. It's supposed to be used
    by V8 jobs accessing V8 heap outside of v8::Isolate::Scope or
    i::LocalHeap or i::LocalIsolate scopes (they already ensure that the
    cage base values are properly initialized).
    For all other build modes PtrComprCageAccessScope is a no-op.

    For simplicity reasons the multi-cage mode is made incompatible with
    external code space.

    Bug: v8:13788, v8:14292
    Change-Id: I06c2d19a1eb7254fa7af07a17617e22d98abea9f
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4846592
    Reviewed-by: Jakob Linke <[email protected]>
    Reviewed-by: Jakob Kummerow <[email protected]>
    Commit-Queue: Igor Sheludko <[email protected]>
    Reviewed-by: Dominik Inführ <[email protected]>
    Cr-Commit-Position: refs/heads/main@{#90075}

Refs: v8/v8@475c8cd
    @kvakil
    kvakil committed Nov 16, 2023
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  2. src: add IsolateScopes before using isolates 

    The V8 API requires entering an isolate before using it. We were often
not doing this, which worked fine in practice. However when (multi-cage)
pointer compression is enabled, the correct isolate needs to be active
in order to decompress pointers correctly, otherwise it causes crashes.

Fix this by sprinkling in some calls to v8::Isolate::Scope::Scope where
they were missing.

This also introduces RAIIIsolateWithoutEntering which is used in
JSONParser to avoid otherwise exposing the Isolate::Scope outside of the
class.

Tested by compiling with `--experimental-enable-pointer-compression`
locally and running all tests.

Refs: nodejs/build#3204 (comment)
Refs: https://bugs.chromium.org/p/v8/issues/detail?id=14292
    @kvakil
    kvakil committed Nov 16, 2023
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