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support creating mutable allocations from byte slices

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This commit is contained in:
Ralf Jung 2021-05-23 12:03:39 +02:00
parent c3005e85da
commit 585141b219
8 changed files with 30 additions and 15 deletions
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12
compiler/rustc_middle/src/mir/interpret/allocation.rs
View file

@ -100,7 +100,11 @@ impl AllocRange {
// The constructors are all without extra; the extra gets added by a machine hook later.
impl<Tag> Allocation<Tag> {
/// Creates a read-only allocation initialized by the given bytes
pub fn from_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>, align: Align) -> Self {
pub fn from_bytes<'a>(
slice: impl Into<Cow<'a, [u8]>>,
align: Align,
mutability: Mutability,
) -> Self {
let bytes = slice.into().into_owned();
let size = Size::from_bytes(bytes.len());
Self {
@ -108,13 +112,13 @@ impl<Tag> Allocation<Tag> {
relocations: Relocations::new(),
init_mask: InitMask::new(size, true),
align,
mutability: Mutability::Not,
mutability,
extra: (),
}
}
pub fn from_byte_aligned_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>) -> Self {
Allocation::from_bytes(slice, Align::ONE)
pub fn from_bytes_byte_aligned_immutable<'a>(slice: impl Into<Cow<'a, [u8]>>) -> Self {
Allocation::from_bytes(slice, Align::ONE, Mutability::Not)
}
pub fn uninit(size: Size, align: Align) -> Self {

2
compiler/rustc_middle/src/ty/context.rs
View file

@ -1072,7 +1072,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// Allocates a read-only byte or string literal for `mir::interpret`.
pub fn allocate_bytes(self, bytes: &[u8]) -> interpret::AllocId {
// Create an allocation that just contains these bytes.
let alloc = interpret::Allocation::from_byte_aligned_bytes(bytes);
let alloc = interpret::Allocation::from_bytes_byte_aligned_immutable(bytes);
let alloc = self.intern_const_alloc(alloc);
self.create_memory_alloc(alloc)
}

5
compiler/rustc_mir/src/const_eval/eval_queries.rs
View file

@ -169,8 +169,9 @@ pub(super) fn op_to_const<'tcx>(
(ecx.tcx.global_alloc(ptr.alloc_id).unwrap_memory(), ptr.offset.bytes())
}
Scalar::Int { .. } => (
ecx.tcx
.intern_const_alloc(Allocation::from_byte_aligned_bytes(b"" as &[u8])),
ecx.tcx.intern_const_alloc(Allocation::from_bytes_byte_aligned_immutable(
b"" as &[u8],
)),
0,
),
};

4
compiler/rustc_mir/src/interpret/intrinsics/caller_location.rs
View file

@ -1,5 +1,6 @@
use std::convert::TryFrom;
use rustc_ast::Mutability;
use rustc_hir::lang_items::LangItem;
use rustc_middle::mir::TerminatorKind;
use rustc_middle::ty::subst::Subst;
@ -79,7 +80,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
line: u32,
col: u32,
) -> MPlaceTy<'tcx, M::PointerTag> {
let file = self.allocate_str(&filename.as_str(), MemoryKind::CallerLocation);
let file =
self.allocate_str(&filename.as_str(), MemoryKind::CallerLocation, Mutability::Not);
let line = Scalar::from_u32(line);
let col = Scalar::from_u32(col);

2
compiler/rustc_mir/src/interpret/intrinsics/type_name.rs
View file

@ -197,6 +197,6 @@ impl Write for AbsolutePathPrinter<'_> {
/// Directly returns an `Allocation` containing an absolute path representation of the given type.
crate fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> &'tcx Allocation {
let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path;
let alloc = Allocation::from_byte_aligned_bytes(path.into_bytes());
let alloc = Allocation::from_bytes_byte_aligned_immutable(path.into_bytes());
tcx.intern_const_alloc(alloc)
}

4
compiler/rustc_mir/src/interpret/memory.rs
View file

@ -219,9 +219,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
pub fn allocate_bytes(
&mut self,
bytes: &[u8],
align: Align,
kind: MemoryKind<M::MemoryKind>,
mutability: Mutability,
) -> Pointer<M::PointerTag> {
let alloc = Allocation::from_byte_aligned_bytes(bytes);
let alloc = Allocation::from_bytes(bytes, align, mutability);
self.allocate_with(alloc, kind)
}

12
compiler/rustc_mir/src/interpret/place.rs
View file

@ -6,6 +6,7 @@ use std::convert::TryFrom;
use std::fmt::Debug;
use std::hash::Hash;
use rustc_ast::Mutability;
use rustc_macros::HashStable;
use rustc_middle::mir;
use rustc_middle::ty::layout::{PrimitiveExt, TyAndLayout};
@ -1024,18 +1025,23 @@ where
MPlaceTy::from_aligned_ptr(ptr, layout)
}
/// Returns a wide MPlace.
/// Returns a wide MPlace of type `&'static [mut] str` to a new 1-aligned allocation.
pub fn allocate_str(
&mut self,
str: &str,
kind: MemoryKind<M::MemoryKind>,
mutbl: Mutability,
) -> MPlaceTy<'tcx, M::PointerTag> {
let ptr = self.memory.allocate_bytes(str.as_bytes(), kind);
let ptr = self.memory.allocate_bytes(str.as_bytes(), Align::ONE, kind, mutbl);
let meta = Scalar::from_machine_usize(u64::try_from(str.len()).unwrap(), self);
let mplace =
MemPlace { ptr: ptr.into(), align: Align::ONE, meta: MemPlaceMeta::Meta(meta) };
let layout = self.layout_of(self.tcx.mk_static_str()).unwrap();
let ty = self.tcx.mk_ref(
self.tcx.lifetimes.re_static,
ty::TypeAndMut { ty: self.tcx.types.str_, mutbl },
);
let layout = self.layout_of(ty).unwrap();
MPlaceTy { mplace, layout }
}

4
compiler/rustc_mir_build/src/thir/constant.rs
View file

@ -25,14 +25,14 @@ crate fn lit_to_const<'tcx>(
let lit = match (lit, &ty.kind()) {
(ast::LitKind::Str(s, _), ty::Ref(_, inner_ty, _)) if inner_ty.is_str() => {
let s = s.as_str();
let allocation = Allocation::from_byte_aligned_bytes(s.as_bytes());
let allocation = Allocation::from_bytes_byte_aligned_immutable(s.as_bytes());
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: s.len() }
}
(ast::LitKind::ByteStr(data), ty::Ref(_, inner_ty, _))
if matches!(inner_ty.kind(), ty::Slice(_)) =>
{
let allocation = Allocation::from_byte_aligned_bytes(data as &[u8]);
let allocation = Allocation::from_bytes_byte_aligned_immutable(data as &[u8]);
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: data.len() }
}