• Seth Brenith's avatar
    [tools] Use instance types of known Maps in v8_debug_helper · 1d3c4975
    Seth Brenith authored
    If we can read an object's Map pointer but not any data from the Map
    itself, we may still be able to accurately describe the object's type if
    the Map pointer matches one of the known Maps from the snapshot.
    GetObjectProperties uses that data in one of two ways:
    - If it is sure that the Map pointer matches a known Map, then it uses
      the type from that Map and continues as if it read the type normally.
    - If the Map pointer is at the right offset within a heap page to match
      a known Map, but the caller didn't provide the addresses of the first
      pages in Map space or read-only space, then the type of that Map is
      just a guess and gets returned in a separate array. This gives the
      caller the opportunity to present guessed types to the user, and
      perhaps call again using the guessed type as the type hint.
    
    Bug: v8:9376
    Change-Id: I187f67b77e76699863a14534a9d635b79f654124
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1787986
    Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
    Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
    Reviewed-by: 's avatarMichael Achenbach <machenbach@chromium.org>
    Reviewed-by: 's avatarTobias Tebbi <tebbi@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#63908}
    1d3c4975
class-debug-reader-generator.cc 9.85 KB