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Auto merge of #143182 - xdoardo:more-addrspace, r=workingjubilee

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Allow custom default address spaces and parse `p-` specifications in the datalayout string

Some targets, such as CHERI, use as default an address space different from the "normal" default address space `0` (in the case of CHERI, [200 is used](https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-877.pdf)). Currently, `rustc` does not allow to specify custom address spaces and does not take into consideration [`p-` specifications in the datalayout string](https://llvm.org/docs/LangRef.html#langref-datalayout).

This patch tries to mitigate these problems by allowing targets to define a custom default address space (while keeping the default value to address space `0`) and adding the code to parse the `p-` specifications in `rustc_abi`. The main changes are that `TargetDataLayout` now uses functions to refer to pointer-related informations, instead of having specific fields for the size and alignment of pointers in the default address space; furthermore, the two `pointer_size` and `pointer_align` fields in `TargetDataLayout` are replaced with an `FxHashMap` that holds info for all the possible address spaces, as parsed by the `p-` specifications.

The potential performance drawbacks of not having ad-hoc fields for the default address space will be tested in this PR's CI run.

r? workingjubilee
This commit is contained in:
bors 2025-07-07 17:28:14 +00:00
commit 9ac09016b0
5 changed files with 5 additions and 5 deletions
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2
clippy_lints/src/casts/fn_to_numeric_cast.rs
View file

@ -17,7 +17,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>,
ty::FnDef(..) | ty::FnPtr(..) => {
let mut applicability = Applicability::MaybeIncorrect;
if to_nbits >= cx.tcx.data_layout.pointer_size.bits() && !cast_to.is_usize() {
if to_nbits >= cx.tcx.data_layout.pointer_size().bits() && !cast_to.is_usize() {
let from_snippet = snippet_with_applicability(cx, cast_expr.span, "x", &mut applicability);
span_lint_and_sugg(
cx,

2
clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs
View file

@ -17,7 +17,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>,
let mut applicability = Applicability::MaybeIncorrect;
let from_snippet = snippet_with_applicability(cx, cast_expr.span, "x", &mut applicability);
if to_nbits < cx.tcx.data_layout.pointer_size.bits() {
if to_nbits < cx.tcx.data_layout.pointer_size().bits() {
span_lint_and_sugg(
cx,
FN_TO_NUMERIC_CAST_WITH_TRUNCATION,

2
clippy_lints/src/casts/utils.rs
View file

@ -5,7 +5,7 @@ use rustc_middle::ty::{self, AdtDef, IntTy, Ty, TyCtxt, UintTy, VariantDiscr};
/// integral type.
pub(super) fn int_ty_to_nbits(tcx: TyCtxt<'_>, ty: Ty<'_>) -> Option<u64> {
match ty.kind() {
ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Some(tcx.data_layout.pointer_size.bits()),
ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Some(tcx.data_layout.pointer_size().bits()),
ty::Int(i) => i.bit_width(),
ty::Uint(i) => i.bit_width(),
_ => None,

2
clippy_lints/src/enum_clike.rs
View file

@ -35,7 +35,7 @@ declare_lint_pass!(UnportableVariant => [ENUM_CLIKE_UNPORTABLE_VARIANT]);
impl<'tcx> LateLintPass<'tcx> for UnportableVariant {
#[expect(clippy::cast_possible_wrap)]
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
if cx.tcx.data_layout.pointer_size.bits() != 64 {
if cx.tcx.data_layout.pointer_size().bits() != 64 {
return;
}
if let ItemKind::Enum(_, _, def) = &item.kind {

2
clippy_utils/src/consts.rs
View file

@ -918,7 +918,7 @@ fn mir_is_empty<'tcx>(tcx: TyCtxt<'tcx>, result: mir::Const<'tcx>) -> Option<boo
// Get the length from the slice, using the same formula as
// [`ConstValue::try_get_slice_bytes_for_diagnostics`].
let a = tcx.global_alloc(alloc_id).unwrap_memory().inner();
let ptr_size = tcx.data_layout.pointer_size;
let ptr_size = tcx.data_layout.pointer_size();
if a.size() < offset + 2 * ptr_size {
// (partially) dangling reference
return None;