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

Author: bors

compiler/rustc_abi/src/lib.rs

@@ -55,7 +55,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// Get the maximum value of int_ty. It is platform-dependent due to the byte size of isize
     fn int_ty_max(&self, int_ty: IntTy) -> u128 {
         match int_ty {
-            IntTy::Isize => self.tcx.data_layout.pointer_size.signed_int_max() as u128,
+            IntTy::Isize => self.tcx.data_layout.pointer_size().signed_int_max() as u128,
             IntTy::I8 => i8::MAX as u128,
             IntTy::I16 => i16::MAX as u128,
             IntTy::I32 => i32::MAX as u128,
@@ -67,7 +67,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// Get the maximum value of uint_ty. It is platform-dependent due to the byte size of usize
     fn uint_ty_max(&self, uint_ty: UintTy) -> u128 {
         match uint_ty {
-            UintTy::Usize => self.tcx.data_layout.pointer_size.unsigned_int_max(),
+            UintTy::Usize => self.tcx.data_layout.pointer_size().unsigned_int_max(),
             UintTy::U8 => u8::MAX as u128,
             UintTy::U16 => u16::MAX as u128,
             UintTy::U32 => u32::MAX as u128,

compiler/rustc_ast_lowering/src/format.rs

@@ -786,7 +786,7 @@ pub(crate) fn codegen_drop<'tcx>(
 
 pub(crate) fn lib_call_arg_param(tcx: TyCtxt<'_>, ty: Type, is_signed: bool) -> AbiParam {
     let param = AbiParam::new(ty);
-    if ty.is_int() && u64::from(ty.bits()) < tcx.data_layout.pointer_size.bits() {
+    if ty.is_int() && u64::from(ty.bits()) < tcx.data_layout.pointer_size().bits() {
         match (&*tcx.sess.target.arch, &*tcx.sess.target.vendor) {
             ("x86_64", _) | ("aarch64", "apple") => match (ty, is_signed) {
                 (types::I8 | types::I16, true) => param.sext(),

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -127,7 +127,7 @@ impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
             PassMode::Indirect { attrs, meta_attrs: None, on_stack } => {
                 if on_stack {
                     // Abi requires aligning struct size to pointer size
-                    let size = self.layout.size.align_to(tcx.data_layout.pointer_align.abi);
+                    let size = self.layout.size.align_to(tcx.data_layout.pointer_align().abi);
                     let size = u32::try_from(size.bytes()).unwrap();
                     smallvec![apply_attrs_to_abi_param(
                         AbiParam::special(pointer_ty(tcx), ArgumentPurpose::StructArgument(size),),

compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs

@@ -15,7 +15,7 @@ use crate::debuginfo::FunctionDebugContext;
 use crate::prelude::*;
 
 pub(crate) fn pointer_ty(tcx: TyCtxt<'_>) -> types::Type {
-    match tcx.data_layout.pointer_size.bits() {
+    match tcx.data_layout.pointer_size().bits() {
         16 => types::I16,
         32 => types::I32,
         64 => types::I64,

compiler/rustc_codegen_cranelift/src/common.rs

@@ -443,7 +443,7 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
             let addend = {
                 let endianness = tcx.data_layout.endian;
                 let offset = offset.bytes() as usize;
-                let ptr_size = tcx.data_layout.pointer_size;
+                let ptr_size = tcx.data_layout.pointer_size();
                 let bytes = &alloc.inspect_with_uninit_and_ptr_outside_interpreter(
                     offset..offset + ptr_size.bytes() as usize,
                 );

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -162,7 +162,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
     }
 
     fn const_usize(&self, i: u64) -> RValue<'gcc> {
-        let bit_size = self.data_layout().pointer_size.bits();
+        let bit_size = self.data_layout().pointer_size().bits();
         if bit_size < 64 {
             // make sure it doesn't overflow
             assert!(i < (1 << bit_size));

compiler/rustc_codegen_gcc/src/common.rs

@@ -294,7 +294,7 @@ pub(crate) fn const_alloc_to_gcc_uncached<'gcc>(
     let alloc = alloc.inner();
     let mut llvals = Vec::with_capacity(alloc.provenance().ptrs().len() + 1);
     let dl = cx.data_layout();
-    let pointer_size = dl.pointer_size.bytes() as usize;
+    let pointer_size = dl.pointer_size().bytes() as usize;
 
     let mut next_offset = 0;
     for &(offset, prov) in alloc.provenance().ptrs().iter() {
@@ -331,7 +331,7 @@ pub(crate) fn const_alloc_to_gcc_uncached<'gcc>(
             ),
             abi::Scalar::Initialized {
                 value: Primitive::Pointer(address_space),
-                valid_range: WrappingRange::full(dl.pointer_size),
+                valid_range: WrappingRange::full(dl.pointer_size()),
             },
             cx.type_i8p_ext(address_space),
         ));

compiler/rustc_codegen_gcc/src/consts.rs

@@ -541,7 +541,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
                         // For rusty ABIs, small aggregates are actually passed
                         // as `RegKind::Integer` (see `FnAbi::adjust_for_abi`),
                         // so we re-use that same threshold here.
-                        layout.size() <= self.data_layout().pointer_size * 2
+                        layout.size() <= self.data_layout().pointer_size() * 2
                     }
                 };
 

compiler/rustc_codegen_gcc/src/intrinsic/mod.rs

@@ -1184,7 +1184,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         let lhs = args[0].immediate();
         let rhs = args[1].immediate();
         let is_add = name == sym::simd_saturating_add;
-        let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
+        let ptr_bits = bx.tcx().data_layout.pointer_size().bits() as _;
         let (signed, elem_width, elem_ty) = match *in_elem.kind() {
             ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits) / 8, bx.cx.type_int_from_ty(i)),
             ty::Uint(i) => {