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Leszek Swirski authored
This is a reland of ae0752df Reland fixes: * Remove UNREACHABLE() from constexpr switch, since we don't have a CONSTEXPR_UNREACHABLE() (it's ok, the switch is exhaustive for the enum anyway). * Fix IsRegisterArray trait to use public inheritance and size_t for std::array size. 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} TBR=nicohartmann@chromium.org,clemensb@chromium.org,ishell@chromium.org,clemensb@chromium.org Bug: v8:11420 Change-Id: Icd1f6cdb3c178e74460044b1e9623139929ceba8 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2831872Reviewed-by: Leszek Swirski <leszeks@chromium.org> Reviewed-by: Clemens Backes <clemensb@chromium.org> Reviewed-by: Igor Sheludko <ishell@chromium.org> Commit-Queue: Leszek Swirski <leszeks@chromium.org> Cr-Commit-Position: refs/heads/master@{#74010}
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