• Benedikt Meurer's avatar
    [debug] Implement stepping out of async functions in the debugger. · 536e96cc
    Benedikt Meurer authored
    Previously the inspector was trying to handle step-out for async
    functions by annotating the async stacks, but this was merely a
    hack and didn't work reliably
    
    (a) when the async caller that is `await`ing the result of the
        callee was still in the synchronous part (because then there
        was no async task yet in the inspector), or
    (b) not at all when the async stack tracking wasn't enabled or the
        maximum async stack depth was too small.
    
    This CL replaces that hack with a pragmatic solution inside the
    V8 debugger, where upon `await` we memorize the async function
    object of the caller on the outer promise of the callee, and when
    stepping out of the callee we check whether the returned promise
    has a memorized async function object and if so, we schedule that
    to resume.
    
    This CL thereby effectively reverts https://crrev.com/c/1054618
    and replaces it with a V8 debug solution, and thereby further
    reduces the (memory) overhead of an AsyncStackTrace.
    
    Fixed: chromium:1246867
    Bug: v8:6161, v8:7753, chromium:1277451, chromium:1280519
    Change-Id: I6aa79e90f49d204f66bfd37e7a328c7fb8d635b1
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3439865Reviewed-by: 's avatarJaroslav Sevcik <jarin@chromium.org>
    Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
    Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#78990}
    536e96cc