Auto merge of #128812 - nnethercote:shrink-TyKind-FnPtr, r=compiler-errors

Shrink `TyKind::FnPtr`.

By splitting the `FnSig` within `TyKind::FnPtr` into `FnSigTys` and `FnHeader`, which can be packed more efficiently. This reduces the size of the hot `TyKind` type from 32 bytes to 24 bytes on 64-bit platforms. This reduces peak memory usage by a few percent on some benchmarks. It also reduces cache misses and page faults similarly, though this doesn't translate to clear cycles or wall-time improvements on CI.

r? `@compiler-errors`
This commit is contained in:
bors 2024-08-14 00:56:53 +00:00
commit e9c965df7b
89 changed files with 315 additions and 231 deletions

View file

@ -213,9 +213,8 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
// NOTE: we cannot remove this match like in the LLVM codegen because the call
// to fn_ptr_backend_type handle the on-stack attribute.
// TODO(antoyo): find a less hackish way to hande the on-stack attribute.
ty::FnPtr(sig) => {
cx.fn_ptr_backend_type(cx.fn_abi_of_fn_ptr(sig, ty::List::empty()))
}
ty::FnPtr(sig_tys, hdr) => cx
.fn_ptr_backend_type(cx.fn_abi_of_fn_ptr(sig_tys.with(hdr), ty::List::empty())),
_ => self.scalar_gcc_type_at(cx, scalar, Size::ZERO),
};
cx.scalar_types.borrow_mut().insert(self.ty, ty);