• Milad Fa's avatar
    PPC: [builtins] Add 'RestartFrameTrampoline' · 692aeb27
    Milad Fa authored
    Port b0118171
    
    Original Commit Message:
    
        This CL adds a new builtin called "RestartFrameTrampoline". This
        trampoline is relatively simple: It leaves the current frame and
        re-invokes the function. This essentially restarts the function and
        is one of the key components required to bring back the "Restart
        frame" DevTools debugging feature.
    
        The builtin is closely related to the "FrameDropperTrampoline"
        removed in the CL https://crrev.com/c/2854750. The key difference
        is that the "FrameDropperTrampoline" dropped to an "arbitrary"
        frame pointer before restarting the function (arbitrary in the
        sense that it was provided as an argument). This caused issues
        as the feature was implemented in a way that the frame pointer
        wasn't necessarily valid anymore.
    
        In comparison, the "RestartFrameTrampoline" relies on the V8
        unwinder to drop it in the correct frame first and is then
        invoked via either the CEntry stub or the deoptimizer
        (see design doc for details).
    
    R=szuend@chromium.org, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
    BUG=
    LOG=N
    
    Change-Id: Id742eeaa59a540ec206a92308fb72bb50413e267
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3613391Reviewed-by: 's avatarSimon Zünd <szuend@chromium.org>
    Commit-Queue: Milad Farazmand <mfarazma@redhat.com>
    Cr-Commit-Position: refs/heads/main@{#80264}
    692aeb27
builtins-ppc.cc 142 KB