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

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

8 files changed, 11 insertions, 10 deletions

diff --git a/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast.rs b/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast.rs
index 105477093b5..55e27a05f3c 100644
--- a/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast.rs
@@ -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,
diff --git a/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs b/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs
index 700b7d0d426..4da79205e20 100644
--- a/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs
@@ -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,
diff --git a/src/tools/clippy/clippy_lints/src/casts/utils.rs b/src/tools/clippy/clippy_lints/src/casts/utils.rs
index 318a1646477..d846d78b9ee 100644
--- a/src/tools/clippy/clippy_lints/src/casts/utils.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/utils.rs
@@ -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,
diff --git a/src/tools/clippy/clippy_lints/src/enum_clike.rs b/src/tools/clippy/clippy_lints/src/enum_clike.rs
index 098571a5351..c828fc57f76 100644
--- a/src/tools/clippy/clippy_lints/src/enum_clike.rs
+++ b/src/tools/clippy/clippy_lints/src/enum_clike.rs
@@ -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 {
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index 09299c869dc..ba0376e4d40 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -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;
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs b/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
index 3fa2bfbd1b7..107da6a5af6 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/layout.rs
@@ -261,7 +261,7 @@ pub fn layout_of_ty_query(
         }
         // Potentially-wide pointers.
         TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {
-            let mut data_ptr = scalar_unit(dl, Primitive::Pointer(AddressSpace::DATA));
+            let mut data_ptr = scalar_unit(dl, Primitive::Pointer(AddressSpace::ZERO));
             if matches!(ty.kind(Interner), TyKind::Ref(..)) {
                 data_ptr.valid_range_mut().start = 1;
             }
@@ -285,7 +285,7 @@ pub fn layout_of_ty_query(
                     scalar_unit(dl, Primitive::Int(dl.ptr_sized_integer(), false))
                 }
                 TyKind::Dyn(..) => {
-                    let mut vtable = scalar_unit(dl, Primitive::Pointer(AddressSpace::DATA));
+                    let mut vtable = scalar_unit(dl, Primitive::Pointer(AddressSpace::ZERO));
                     vtable.valid_range_mut().start = 1;
                     vtable
                 }
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/layout/target.rs b/src/tools/rust-analyzer/crates/hir-ty/src/layout/target.rs
index e1e1c44996c..88c33ecccad 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/layout/target.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/layout/target.rs
@@ -2,7 +2,7 @@
 
 use base_db::Crate;
 use hir_def::layout::TargetDataLayout;
-use rustc_abi::{AlignFromBytesError, TargetDataLayoutErrors};
+use rustc_abi::{AlignFromBytesError, TargetDataLayoutErrors, AddressSpace};
 use triomphe::Arc;
 
 use crate::db::HirDatabase;
@@ -12,7 +12,7 @@ pub fn target_data_layout_query(
     krate: Crate,
 ) -> Result<Arc<TargetDataLayout>, Arc<str>> {
     match &krate.workspace_data(db).data_layout {
-        Ok(it) => match TargetDataLayout::parse_from_llvm_datalayout_string(it) {
+        Ok(it) => match TargetDataLayout::parse_from_llvm_datalayout_string(it, AddressSpace::ZERO) {
             Ok(it) => Ok(Arc::new(it)),
             Err(e) => {
                 Err(match e {
@@ -39,6 +39,7 @@ pub fn target_data_layout_query(
                         target,
                     } => format!(r#"inconsistent target specification: "data-layout" claims pointers are {pointer_size}-bit, while "target-pointer-width" is `{target}`"#),
                     TargetDataLayoutErrors::InvalidBitsSize { err } => err,
+                    TargetDataLayoutErrors::UnknownPointerSpecification { err } => format!(r#"use of unknown pointer specifer in "data-layout": {err}"#),
                 }.into())
             }
         },
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/mir/eval.rs b/src/tools/rust-analyzer/crates/hir-ty/src/mir/eval.rs
index 1ec55a82092..55fada14363 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/mir/eval.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/mir/eval.rs
@@ -630,7 +630,7 @@ impl Evaluator<'_> {
             Ok(target_data_layout) => target_data_layout,
             Err(e) => return Err(MirEvalError::TargetDataLayoutNotAvailable(e)),
         };
-        let cached_ptr_size = target_data_layout.pointer_size.bytes_usize();
+        let cached_ptr_size = target_data_layout.pointer_size().bytes_usize();
         Ok(Evaluator {
             target_data_layout,
             stack: vec![0],