• Junliang Yan's avatar
    PPC/s390: [liftoff] Cache the instance in a register · a9f2bb0b
    Junliang Yan authored
    Port adf035fb
    
    Original Commit Message:
    
        This CL avoids redundant loads of the instance from the frame by caching
        it in a register if possible. This register will be the first one to be
        cleared once we run out of registers (hence it's called a "volatile
        register"). On local tests, this seems to reduce most redundant loads
        within a function, and it also reduces the load for the stack check in
        the function prologue.
        After the stack check, we need to discard the cached instance though,
        since the potential runtime call for the stack check might clobber it.
        This will be addressed in a follow-up CL by re-loading the cached
        instance after the stack check. This is expected to remove another good
        chunk of instance loads, because the instance would initially be
        available in a register when starting the function code.
    
    R=clemensb@chromium.org, midawson@redhat.com, mfarazma@redhat.com
    BUG=
    LOG=N
    
    Change-Id: I3756ce98d4dfefb44c946a4948f1a6dbe0ce44dd
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2698291Reviewed-by: 's avatarMilad Fa <mfarazma@redhat.com>
    Commit-Queue: Junliang Yan <junyan@redhat.com>
    Cr-Commit-Position: refs/heads/master@{#72791}
    a9f2bb0b
liftoff-assembler-ppc.h 68.3 KB