• Leszek Swirski's avatar
    Revert "[codegen] Add static interface descriptors" · 5dea60d6
    Leszek Swirski authored
    This reverts commit ae0752df.
    
    Reason for revert: Predictably, constexpr issues on non-clang compilers.
    
    Original change's description:
    > [codegen] Add static interface descriptors
    >
    > Add a new CRTP StaticCallInterfaceDescriptor class, which provides
    > static constexpr getters for a descriptor's registers, parameter counts,
    > and so on. Each CallInterfaceDescriptor subclass is changed to extend
    > StaticCallInterfaceDescriptor, with StaticCallInterfaceDescriptor itself
    > extending CallInterfaceDescriptor to still provide a dynamic lookup
    > where needed.
    >
    > StaticCallInterfaceDescriptor provides a couple of customisation points,
    > where it reads its CRTP derived descriptor's static fields and
    > functions, with default fallbacks where appropriate. With these
    > customisation points, the definition of CallInterfaceDescriptor
    > subclasses is simplified to:
    >
    >     a) Providing parameter names (as before)
    >     b) Providing parameter types (as before)
    >     c) Optionally setting flags (like kNoContext or kAllowVarArgs) as
    >        static booleans on the class.
    >     d) Optionally providing a `registers()` method that returns a
    >        std::array<Register, N> of registers that may be used for
    >        parameters (if not provided, this defaults to the implementation
    >        specific default register set).
    >
    > Parameter registers (and register count) are automagically set based on
    > the number of parameters and number of given registers, with extra magic
    > to ignore no_reg registers (to reduce ia32 special casing). The
    > CallInterfaceDescriptorData is initialized based on these static
    > functions, rather than manual per-descriptor initializers.
    >
    > This allows us to skip loading descriptors dynamically for CallBuiltin
    > in Sparkplug, and instead lets us use a bit of template magic to
    > statically set up arguments for the calls. Any other users of statically
    > known descriptors will also benefit, thanks to C++ picking the static
    > methods over the dynamic methods on the base class when available.
    >
    > Because we can remove various virtual functions and trigger heavier
    > inlining of constantly known values, binary size slightly decreases with
    > this change.
    >
    > Note that torque-generated descriptors are changed to use the same magic,
    > rather than having Torque-specific magic, for consistency.
    >
    > Bug: v8:11420
    > Change-Id: Icc5e238b6313a08734feb564204a13226b450c22
    > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2814518
    > Auto-Submit: Leszek Swirski <leszeks@chromium.org>
    > Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
    > Reviewed-by: Clemens Backes <clemensb@chromium.org>
    > Reviewed-by: Igor Sheludko <ishell@chromium.org>
    > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
    > Commit-Queue: Clemens Backes <clemensb@chromium.org>
    > Cr-Commit-Position: refs/heads/master@{#73996}
    
    Bug: v8:11420
    Change-Id: Ie5469c9253fc140590ac30b72db6eb1d93f86806
    No-Presubmit: true
    No-Tree-Checks: true
    No-Try: true
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2831485
    Auto-Submit: Leszek Swirski <leszeks@chromium.org>
    Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
    Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
    Cr-Commit-Position: refs/heads/master@{#74000}
    5dea60d6
interface-descriptors-x64.cc 11.3 KB