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Rollup merge of #107248 - erikdesjardins:addrspace, r=oli-obk

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abi: add AddressSpace field to Primitive::Pointer

...and remove it from `PointeeInfo`, which isn't meant for this.

There are still various places (marked with FIXMEs) that assume all pointers
have the same size and alignment. Fixing this requires parsing non-default
address spaces in the data layout string (and various other changes),
which will be done in a followup.
(That is, if it's actually worth it to support multiple different pointer sizes.
There is a lot of code that would be affected by that.)

Fixes #106367

r? ``@oli-obk``
cc ``@Patryk27``
This commit is contained in:
Matthias Krüger 2023-01-26 06:15:27 +01:00 • committed by GitHub
commit a8b5e5d9db
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GPG key ID: 4AEE18F83AFDEB23
28 changed files with 235 additions and 203 deletions
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13
compiler/rustc_middle/src/mir/interpret/mod.rs
View file

@ -110,7 +110,7 @@ use rustc_hir::def_id::DefId;
use rustc_macros::HashStable;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_serialize::{Decodable, Encodable};
use rustc_target::abi::Endian;
use rustc_target::abi::{AddressSpace, Endian, HasDataLayout};
use crate::mir;
use crate::ty::codec::{TyDecoder, TyEncoder};
@ -438,6 +438,17 @@ impl<'tcx> GlobalAlloc<'tcx> {
_ => bug!("expected vtable, got {:?}", self),
}
}
/// The address space that this `GlobalAlloc` should be placed in.
#[inline]
pub fn address_space(&self, cx: &impl HasDataLayout) -> AddressSpace {
match self {
GlobalAlloc::Function(..) => cx.data_layout().instruction_address_space,
GlobalAlloc::Static(..) | GlobalAlloc::Memory(..) | GlobalAlloc::VTable(..) => {
AddressSpace::DATA
}
}
}
}
pub(crate) struct AllocMap<'tcx> {

234
compiler/rustc_middle/src/ty/layout.rs
View file

@ -128,7 +128,8 @@ impl PrimitiveExt for Primitive {
Int(i, signed) => i.to_ty(tcx, signed),
F32 => tcx.types.f32,
F64 => tcx.types.f64,
Pointer => tcx.mk_mut_ptr(tcx.mk_unit()),
// FIXME(erikdesjardins): handle non-default addrspace ptr sizes
Pointer(_) => tcx.mk_mut_ptr(tcx.mk_unit()),
}
}
@ -138,7 +139,11 @@ impl PrimitiveExt for Primitive {
fn to_int_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match *self {
Int(i, signed) => i.to_ty(tcx, signed),
Pointer => tcx.types.usize,
// FIXME(erikdesjardins): handle non-default addrspace ptr sizes
Pointer(_) => {
let signed = false;
tcx.data_layout().ptr_sized_integer().to_ty(tcx, signed)
}
F32 | F64 => bug!("floats do not have an int type"),
}
}
@ -812,132 +817,125 @@ where
let tcx = cx.tcx();
let param_env = cx.param_env();
let addr_space_of_ty = |ty: Ty<'tcx>| {
if ty.is_fn() { cx.data_layout().instruction_address_space } else { AddressSpace::DATA }
};
let pointee_info = match *this.ty.kind() {
ty::RawPtr(mt) if offset.bytes() == 0 => {
tcx.layout_of(param_env.and(mt.ty)).ok().map(|layout| PointeeInfo {
size: layout.size,
align: layout.align.abi,
safe: None,
address_space: addr_space_of_ty(mt.ty),
})
}
ty::FnPtr(fn_sig) if offset.bytes() == 0 => {
tcx.layout_of(param_env.and(tcx.mk_fn_ptr(fn_sig))).ok().map(|layout| PointeeInfo {
size: layout.size,
align: layout.align.abi,
safe: None,
address_space: cx.data_layout().instruction_address_space,
})
}
ty::Ref(_, ty, mt) if offset.bytes() == 0 => {
let address_space = addr_space_of_ty(ty);
let kind = if tcx.sess.opts.optimize == OptLevel::No {
// Use conservative pointer kind if not optimizing. This saves us the
// Freeze/Unpin queries, and can save time in the codegen backend (noalias
// attributes in LLVM have compile-time cost even in unoptimized builds).
PointerKind::SharedMutable
} else {
match mt {
hir::Mutability::Not => {
if ty.is_freeze(tcx, cx.param_env()) {
PointerKind::Frozen
} else {
PointerKind::SharedMutable
}
}
hir::Mutability::Mut => {
// References to self-referential structures should not be considered
// noalias, as another pointer to the structure can be obtained, that
// is not based-on the original reference. We consider all !Unpin
// types to be potentially self-referential here.
if ty.is_unpin(tcx, cx.param_env()) {
PointerKind::UniqueBorrowed
} else {
PointerKind::UniqueBorrowedPinned
}
}
}
};
tcx.layout_of(param_env.and(ty)).ok().map(|layout| PointeeInfo {
size: layout.size,
align: layout.align.abi,
safe: Some(kind),
address_space,
})
}
_ => {
let mut data_variant = match this.variants {
// Within the discriminant field, only the niche itself is
// always initialized, so we only check for a pointer at its
// offset.
//
// If the niche is a pointer, it's either valid (according
// to its type), or null (which the niche field's scalar
// validity range encodes). This allows using
// `dereferenceable_or_null` for e.g., `Option<&T>`, and
// this will continue to work as long as we don't start
// using more niches than just null (e.g., the first page of
// the address space, or unaligned pointers).
Variants::Multiple {
tag_encoding: TagEncoding::Niche { untagged_variant, .. },
tag_field,
..
} if this.fields.offset(tag_field) == offset => {
Some(this.for_variant(cx, untagged_variant))
}
_ => Some(this),
};
if let Some(variant) = data_variant {
// We're not interested in any unions.
if let FieldsShape::Union(_) = variant.fields {
data_variant = None;
}
let pointee_info =
match *this.ty.kind() {
ty::RawPtr(mt) if offset.bytes() == 0 => {
tcx.layout_of(param_env.and(mt.ty)).ok().map(|layout| PointeeInfo {
size: layout.size,
align: layout.align.abi,
safe: None,
})
}
let mut result = None;
if let Some(variant) = data_variant {
let ptr_end = offset + Pointer.size(cx);
for i in 0..variant.fields.count() {
let field_start = variant.fields.offset(i);
if field_start <= offset {
let field = variant.field(cx, i);
result = field.to_result().ok().and_then(|field| {
if ptr_end <= field_start + field.size {
// We found the right field, look inside it.
let field_info =
field.pointee_info_at(cx, offset - field_start);
field_info
ty::FnPtr(fn_sig) if offset.bytes() == 0 => {
tcx.layout_of(param_env.and(tcx.mk_fn_ptr(fn_sig))).ok().map(|layout| {
PointeeInfo { size: layout.size, align: layout.align.abi, safe: None }
})
}
ty::Ref(_, ty, mt) if offset.bytes() == 0 => {
let kind = if tcx.sess.opts.optimize == OptLevel::No {
// Use conservative pointer kind if not optimizing. This saves us the
// Freeze/Unpin queries, and can save time in the codegen backend (noalias
// attributes in LLVM have compile-time cost even in unoptimized builds).
PointerKind::SharedMutable
} else {
match mt {
hir::Mutability::Not => {
if ty.is_freeze(tcx, cx.param_env()) {
PointerKind::Frozen
} else {
None
PointerKind::SharedMutable
}
}
hir::Mutability::Mut => {
// References to self-referential structures should not be considered
// noalias, as another pointer to the structure can be obtained, that
// is not based-on the original reference. We consider all !Unpin
// types to be potentially self-referential here.
if ty.is_unpin(tcx, cx.param_env()) {
PointerKind::UniqueBorrowed
} else {
PointerKind::UniqueBorrowedPinned
}
}
}
};
tcx.layout_of(param_env.and(ty)).ok().map(|layout| PointeeInfo {
size: layout.size,
align: layout.align.abi,
safe: Some(kind),
})
}
_ => {
let mut data_variant = match this.variants {
// Within the discriminant field, only the niche itself is
// always initialized, so we only check for a pointer at its
// offset.
//
// If the niche is a pointer, it's either valid (according
// to its type), or null (which the niche field's scalar
// validity range encodes). This allows using
// `dereferenceable_or_null` for e.g., `Option<&T>`, and
// this will continue to work as long as we don't start
// using more niches than just null (e.g., the first page of
// the address space, or unaligned pointers).
Variants::Multiple {
tag_encoding: TagEncoding::Niche { untagged_variant, .. },
tag_field,
..
} if this.fields.offset(tag_field) == offset => {
Some(this.for_variant(cx, untagged_variant))
}
_ => Some(this),
};
if let Some(variant) = data_variant {
// We're not interested in any unions.
if let FieldsShape::Union(_) = variant.fields {
data_variant = None;
}
}
let mut result = None;
if let Some(variant) = data_variant {
// FIXME(erikdesjardins): handle non-default addrspace ptr sizes
// (requires passing in the expected address space from the caller)
let ptr_end = offset + Pointer(AddressSpace::DATA).size(cx);
for i in 0..variant.fields.count() {
let field_start = variant.fields.offset(i);
if field_start <= offset {
let field = variant.field(cx, i);
result = field.to_result().ok().and_then(|field| {
if ptr_end <= field_start + field.size {
// We found the right field, look inside it.
let field_info =
field.pointee_info_at(cx, offset - field_start);
field_info
} else {
None
}
});
if result.is_some() {
break;
}
});
if result.is_some() {
break;
}
}
}
}
// FIXME(eddyb) This should be for `ptr::Unique<T>`, not `Box<T>`.
if let Some(ref mut pointee) = result {
if let ty::Adt(def, _) = this.ty.kind() {
if def.is_box() && offset.bytes() == 0 {
pointee.safe = Some(PointerKind::UniqueOwned);
// FIXME(eddyb) This should be for `ptr::Unique<T>`, not `Box<T>`.
if let Some(ref mut pointee) = result {
if let ty::Adt(def, _) = this.ty.kind() {
if def.is_box() && offset.bytes() == 0 {
pointee.safe = Some(PointerKind::UniqueOwned);
}
}
}
}
result
}
};
result
}
};
debug!(
"pointee_info_at (offset={:?}, type kind: {:?}) => {:?}",