• Toon Verwaest's avatar
    Reland^2 "[runtime] Move Context::native_context to the map" · 3cad6bf5
    Toon Verwaest authored
    This is a reland of c7c47c68.
    
    This makes TSAN happy in addition to:
    
    Previously I presumed that the context read from a frame in the profiler was
    a valid context. Turns out that on non-intel we're not guaranteed that the
    frame is properly set up. In the case we looked at, the profiler took a
    sample right before writing the frame marker indicating a builtin frame,
    causing the "context" pointer from that frame to be a bytecode array. Since
    we'll read random garbage on the stack as a possible context pointer, I made
    the code reading the native context from it a little more defensive.
    
    Bug: v8:9860
    Tbr: ulan@chromium.org, neis@chromium.org, ishell@chromium.org
    
    Original change's description:
    > [runtime] Move Context::native_context to the map
    >
    > Remove the native context slot from contexts by making context maps
    > native-context-specific. Now we require 2 loads to go from a context to the
    > native context, but we have 1 field fewer to store when creating contexts.
    >
    > Change-Id: I3c0d7c50c94060c4129db684f46a567de6f30e8d
    > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1859629
    > Commit-Queue: Toon Verwaest <verwaest@chromium.org>
    > Reviewed-by: Igor Sheludko <ishell@chromium.org>
    > Reviewed-by: Peter Marshall <petermarshall@chromium.org>
    > Reviewed-by: Maya Lekova <mslekova@chromium.org>
    > Reviewed-by: Georg Neis <neis@chromium.org>
    > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
    > Reviewed-by: Toon Verwaest <verwaest@chromium.org>
    > Cr-Commit-Position: refs/heads/master@{#64296}
    
    Change-Id: I4d0ab4cbbb23a9ae616407f17ef8f35a0b68ddb4
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1864654
    Commit-Queue: Toon Verwaest <verwaest@chromium.org>
    Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
    Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
    Reviewed-by: 's avatarIgor Sheludko <ishell@chromium.org>
    Reviewed-by: 's avatarPeter Marshall <petermarshall@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#64360}
    3cad6bf5
js-native-context-specialization.h 12 KB