From e8ade24e14616a79add6d7d37e555b5d34f40e78 Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote Date: Thu, 8 Aug 2024 17:18:20 +1000 Subject: [PATCH] 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. --- src/type_of.rs | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/src/type_of.rs b/src/type_of.rs index d85ed4f12ffa..b7b1be5369c4 100644 --- a/src/type_of.rs +++ b/src/type_of.rs @@ -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);