• Adam Klein's avatar
    Simplify FunctionKind, saving 4 bits in SharedFunctionInfo · 9f9550ef
    Adam Klein authored
    Since we only need to store 18 different function kinds,
    the bitfield approach was wasting space (requiring 11 bits).
    
    This patch replaces the bitfield with a regular enum, and
    updates all the FunctionKind predicates to use comparisons
    instead of bitwise ops.
    
    For the small amount of builtin code that depended upon being
    able to do masking to determine whether something is a class
    constructor, we still store two extra bits on FunctionKind,
    which are computed when the SFI is initialized.
    
    If this approach causes performance regressions (i.e., if it
    turns out that other code was implicitly depending on masking
    for fast checks), we can revert this or address it in
    other ways (e.g., by doing similar caching of repeated checks
    in the caller).
    
    This is a reland of 42667bab.
    
    Bug: v8:7310
    Change-Id: I2ec54289ea687399c61d75b7aff2d849861a64f2
    Reviewed-on: https://chromium-review.googlesource.com/934864Reviewed-by: 's avatarSathya Gunasekaran <gsathya@chromium.org>
    Commit-Queue: Adam Klein <adamk@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#51534}
    9f9550ef
shared-function-info.h 20.2 KB