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

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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
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9
compiler/rustc_lint/src/types.rs
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@ -1022,7 +1022,7 @@ fn ty_is_known_nonnull<'tcx>(
let ty = tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty);
match ty.kind() {
ty::FnPtr(_) => true,
ty::FnPtr(..) => true,
ty::Ref(..) => true,
ty::Adt(def, _) if def.is_box() && matches!(mode, CItemKind::Definition) => true,
ty::Adt(def, args) if def.repr().transparent() && !def.is_union() => {
@ -1473,7 +1473,8 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
ty::Array(inner_ty, _) => self.check_type_for_ffi(cache, inner_ty),
ty::FnPtr(sig) => {
ty::FnPtr(sig_tys, hdr) => {
let sig = sig_tys.with(hdr);
if self.is_internal_abi(sig.abi()) {
return FfiUnsafe {
ty,
@ -1709,8 +1710,8 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
type Result = ControlFlow<Ty<'tcx>>;
fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
if let ty::FnPtr(sig) = ty.kind()
&& !self.visitor.is_internal_abi(sig.abi())
if let ty::FnPtr(_, hdr) = ty.kind()
&& !self.visitor.is_internal_abi(hdr.abi)
{
self.tys.push(ty);
}