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Fix size_of_val and support min_align_of_val #15222

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merged 1 commit into from
Jul 6, 2023
Merged

Fix size_of_val and support min_align_of_val #15222

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5 changes: 5 additions & 0 deletions crates/hir-expand/src/name.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -282,8 +282,10 @@ pub mod known {
alloc,
iter,
ops,
fmt,
future,
result,
string,
boxed,
option,
prelude,
Expand Down Expand Up @@ -311,6 +313,7 @@ pub mod known {
RangeToInclusive,
RangeTo,
Range,
String,
Neg,
Not,
None,
Expand All @@ -321,6 +324,7 @@ pub mod known {
iter_mut,
len,
is_empty,
as_str,
new,
// Builtin macros
asm,
Expand All @@ -334,6 +338,7 @@ pub mod known {
core_panic,
env,
file,
format,
format_args_nl,
format_args,
global_asm,
Expand Down
14 changes: 0 additions & 14 deletions crates/hir-ty/src/consteval/tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2456,20 +2456,6 @@ fn const_trait_assoc() {
);
}

#[test]
fn panic_messages() {
check_fail(
r#"
//- minicore: panic
const GOAL: u8 = {
let x: u16 = 2;
panic!("hello");
};
"#,
|e| e == ConstEvalError::MirEvalError(MirEvalError::Panic("hello".to_string())),
);
}

#[test]
fn exec_limits() {
check_fail(
Expand Down
75 changes: 75 additions & 0 deletions crates/hir-ty/src/consteval/tests/intrinsics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,50 @@ fn size_of_val() {
"#,
12,
);
check_number(
r#"
//- minicore: coerce_unsized, transmute
use core::mem::transmute;
extern "rust-intrinsic" {
pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
}
struct X {
x: i64,
y: u8,
t: [i32],
}
const GOAL: usize = unsafe {
let y: &X = transmute([0usize, 3]);
size_of_val(y)
};
"#,
24,
);
check_number(
r#"
//- minicore: coerce_unsized, transmute
use core::mem::transmute;
extern "rust-intrinsic" {
pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
}
struct X {
x: i32,
y: i64,
t: [u8],
}
const GOAL: usize = unsafe {
let y: &X = transmute([0usize, 15]);
size_of_val(y)
};
"#,
32,
);
check_number(
r#"
//- minicore: coerce_unsized, fmt, builtin_impls
Expand Down Expand Up @@ -74,6 +118,37 @@ fn size_of_val() {
);
}

#[test]
fn min_align_of_val() {
check_number(
r#"
//- minicore: coerce_unsized
extern "rust-intrinsic" {
pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
}
struct X(i32, u8);
const GOAL: usize = min_align_of_val(&X(1, 2));
"#,
4,
);
check_number(
r#"
//- minicore: coerce_unsized
extern "rust-intrinsic" {
pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
}
const GOAL: usize = {
let x: &[i32] = &[1, 2, 3];
min_align_of_val(x)
};
"#,
4,
);
}

#[test]
fn transmute() {
check_number(
Expand Down
2 changes: 1 addition & 1 deletion crates/hir-ty/src/layout/adt.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,7 @@ pub fn layout_of_adt_query(
&& variants
.iter()
.next()
.and_then(|x| x.last().map(|x| x.is_unsized()))
.and_then(|x| x.last().map(|x| !x.is_unsized()))
.unwrap_or(true),
)
.ok_or(LayoutError::SizeOverflow)?
Expand Down
162 changes: 100 additions & 62 deletions crates/hir-ty/src/mir/eval/shim.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,10 @@

use std::cmp;

use chalk_ir::TyKind;
use hir_def::resolver::HasResolver;
use hir_expand::mod_path::ModPath;

use super::*;

mod simd;
Expand Down Expand Up @@ -186,44 +190,24 @@ impl Evaluator<'_> {
BeginPanic => Err(MirEvalError::Panic("<unknown-panic-payload>".to_string())),
PanicFmt => {
let message = (|| {
let arguments_struct =
self.db.lang_item(self.crate_id, LangItem::FormatArguments)?.as_struct()?;
let arguments_layout = self
.layout_adt(arguments_struct.into(), Substitution::empty(Interner))
.ok()?;
let arguments_field_pieces =
self.db.struct_data(arguments_struct).variant_data.field(&name![pieces])?;
let pieces_offset = arguments_layout
.fields
.offset(u32::from(arguments_field_pieces.into_raw()) as usize)
.bytes_usize();
let ptr_size = self.ptr_size();
let arg = args.next()?;
let pieces_array_addr =
Address::from_bytes(&arg[pieces_offset..pieces_offset + ptr_size]).ok()?;
let pieces_array_len = usize::from_le_bytes(
(&arg[pieces_offset + ptr_size..pieces_offset + 2 * ptr_size])
.try_into()
.ok()?,
);
let mut message = "".to_string();
for i in 0..pieces_array_len {
let piece_ptr_addr = pieces_array_addr.offset(2 * i * ptr_size);
let piece_addr =
Address::from_bytes(self.read_memory(piece_ptr_addr, ptr_size).ok()?)
.ok()?;
let piece_len = usize::from_le_bytes(
self.read_memory(piece_ptr_addr.offset(ptr_size), ptr_size)
.ok()?
.try_into()
.ok()?,
);
let piece_data = self.read_memory(piece_addr, piece_len).ok()?;
message += &std::string::String::from_utf8_lossy(piece_data);
}
Some(message)
let x = self.db.crate_def_map(self.crate_id).crate_root();
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x isn't really a great variable name, especially in this case here. You tend to do that a lot which is why I'm raising that here. (and in cases where we need a quick non describing name like in mapping closures etc we tend to use it, https://github.com/rust-lang/rust-analyzer/blob/master/docs/dev/style.md#variable-naming)

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I will make a de-x-ify follow up PR to remove all xs everywhere.

let resolver = x.resolver(self.db.upcast());
let Some(format_fn) = resolver.resolve_path_in_value_ns_fully(
self.db.upcast(),
&hir_def::path::Path::from_known_path_with_no_generic(ModPath::from_segments(
hir_expand::mod_path::PathKind::Abs,
[name![std], name![fmt], name![format]].into_iter(),
)),
) else {
not_supported!("std::fmt::format not found");
};
let hir_def::resolver::ValueNs::FunctionId(format_fn) = format_fn else { not_supported!("std::fmt::format is not a function") };
let message_string = self.interpret_mir(&*self.db.mir_body(format_fn.into()).map_err(|e| MirEvalError::MirLowerError(format_fn, e))?, args.cloned())?;
let addr = Address::from_bytes(&message_string[self.ptr_size()..2 * self.ptr_size()])?;
let size = from_bytes!(usize, message_string[2 * self.ptr_size()..]);
Ok(std::string::String::from_utf8_lossy(self.read_memory(addr, size)?).into_owned())
})()
.unwrap_or_else(|| "<format-args-evaluation-failed>".to_string());
.unwrap_or_else(|e| format!("Failed to render panic format args: {e:?}"));
Err(MirEvalError::Panic(message))
}
SliceLen => {
Expand Down Expand Up @@ -544,6 +528,13 @@ impl Evaluator<'_> {
let size = self.size_of_sized(ty, locals, "size_of arg")?;
destination.write_from_bytes(self, &size.to_le_bytes()[0..destination.size])
}
"min_align_of" | "pref_align_of" => {
let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
return Err(MirEvalError::TypeError("align_of generic arg is not provided"));
};
let align = self.layout(ty)?.align.abi.bytes();
destination.write_from_bytes(self, &align.to_le_bytes()[0..destination.size])
}
"size_of_val" => {
let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner))
else {
Expand All @@ -552,33 +543,28 @@ impl Evaluator<'_> {
let [arg] = args else {
return Err(MirEvalError::TypeError("size_of_val args are not provided"));
};
let metadata = arg.interval.slice(self.ptr_size()..self.ptr_size() * 2);
let size = match ty.kind(Interner) {
TyKind::Str => return destination.write_from_interval(self, metadata),
TyKind::Slice(inner) => {
let len = from_bytes!(usize, metadata.get(self)?);
len * self.size_of_sized(inner, locals, "slice inner type")?
}
TyKind::Dyn(_) => self.size_of_sized(
self.vtable_map.ty_of_bytes(metadata.get(self)?)?,
locals,
"dyn concrete type",
)?,
_ => self.size_of_sized(
ty,
locals,
"unsized type other than str, slice, and dyn",
)?,
};
destination.write_from_bytes(self, &size.to_le_bytes())
if let Some((size, _)) = self.size_align_of(ty, locals)? {
destination.write_from_bytes(self, &size.to_le_bytes())
} else {
let metadata = arg.interval.slice(self.ptr_size()..self.ptr_size() * 2);
let (size, _) = self.size_align_of_unsized(ty, metadata, locals)?;
destination.write_from_bytes(self, &size.to_le_bytes())
}
}
"min_align_of" | "pref_align_of" => {
let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner))
else {
return Err(MirEvalError::TypeError("align_of generic arg is not provided"));
"min_align_of_val" => {
let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
return Err(MirEvalError::TypeError("min_align_of_val generic arg is not provided"));
};
let align = self.layout(ty)?.align.abi.bytes();
destination.write_from_bytes(self, &align.to_le_bytes()[0..destination.size])
let [arg] = args else {
return Err(MirEvalError::TypeError("min_align_of_val args are not provided"));
};
if let Some((_, align)) = self.size_align_of(ty, locals)? {
destination.write_from_bytes(self, &align.to_le_bytes())
} else {
let metadata = arg.interval.slice(self.ptr_size()..self.ptr_size() * 2);
let (_, align) = self.size_align_of_unsized(ty, metadata, locals)?;
destination.write_from_bytes(self, &align.to_le_bytes())
}
}
"needs_drop" => {
let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner))
Expand Down Expand Up @@ -905,6 +891,58 @@ impl Evaluator<'_> {
}
}

fn size_align_of_unsized(
&mut self,
ty: &Ty,
metadata: Interval,
locals: &Locals<'_>,
) -> Result<(usize, usize)> {
Ok(match ty.kind(Interner) {
TyKind::Str => (from_bytes!(usize, metadata.get(self)?), 1),
TyKind::Slice(inner) => {
let len = from_bytes!(usize, metadata.get(self)?);
let (size, align) = self.size_align_of_sized(inner, locals, "slice inner type")?;
(size * len, align)
}
TyKind::Dyn(_) => self.size_align_of_sized(
self.vtable_map.ty_of_bytes(metadata.get(self)?)?,
locals,
"dyn concrete type",
)?,
TyKind::Adt(id, subst) => {
let id = id.0;
let layout = self.layout_adt(id, subst.clone())?;
let id = match id {
AdtId::StructId(s) => s,
_ => not_supported!("unsized enum or union"),
};
let field_types = &self.db.field_types(id.into());
let last_field_ty =
field_types.iter().rev().next().unwrap().1.clone().substitute(Interner, subst);
let sized_part_size =
layout.fields.offset(field_types.iter().count() - 1).bytes_usize();
let sized_part_align = layout.align.abi.bytes() as usize;
let (unsized_part_size, unsized_part_align) =
self.size_align_of_unsized(&last_field_ty, metadata, locals)?;
let align = sized_part_align.max(unsized_part_align) as isize;
let size = (sized_part_size + unsized_part_size) as isize;
// Must add any necessary padding to `size`
// (to make it a multiple of `align`) before returning it.
//
// Namely, the returned size should be, in C notation:
//
// `size + ((size & (align-1)) ? align : 0)`
//
// emulated via the semi-standard fast bit trick:
//
// `(size + (align-1)) & -align`
let size = (size + (align - 1)) & (-align);
(size as usize, align as usize)
}
_ => not_supported!("unsized type other than str, slice, struct and dyn"),
})
}

fn exec_atomic_intrinsic(
&mut self,
name: &str,
Expand Down