• zhengxing.li's avatar
    X87: [runtime] Optimize and unify rest parameters. · e59af013
    zhengxing.li authored
      port 3ef573e9(r33809)
    
      original commit message:
      Replace the somewhat awkward RestParamAccessStub, which would always
      call into the runtime anyway with a proper FastNewRestParameterStub,
      which is basically based on the code that was already there for strict
      arguments object materialization. But for rest parameters we could
      optimize even further (leading to 8-10x improvements for functions with
      rest parameters), by fixing the internal formal parameter count:
    
      Every SharedFunctionInfo has a formal_parameter_count field, which
      specifies the number of formal parameters, and is used to decide whether
      we need to create an arguments adaptor frame when calling a function
      (i.e. if there's a mismatch between the actual and expected parameters).
      Previously the formal_parameter_count included the rest parameter, which
      was sort of unfortunate, as that meant that calling a function with only
      the non-rest parameters still required an arguments adaptor (plus some
      other oddities). Now with this CL we fix, so that we do no longer
      include the rest parameter in that count. Thereby checking for rest
      parameters is very efficient, as we only need to check whether there is
      an arguments adaptor frame, and if not create an empty array, otherwise
      check whether the arguments adaptor frame has more parameters than
      specified by the formal_parameter_count.
    
      The FastNewRestParameterStub is written in a way that it can be directly
      used by Ignition as well, and with some tweaks to the TurboFan backends
      and the CodeStubAssembler, we should be able to rewrite it as
      TurboFanCodeStub in the near future.
    
      Drive-by-fix: Refactor and unify the CreateArgumentsType which was
      different in TurboFan and Ignition; now we have a single enum class
      which is used in both TurboFan and Ignition.
    
    BUG=
    
    Review URL: https://codereview.chromium.org/1696063002
    
    Cr-Commit-Position: refs/heads/master@{#33971}
    e59af013
interface-descriptors-x87.cc 13.6 KB