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Refactor using the type-level constant value ty::Value

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Signed-off-by: FedericoBruzzone <federico.bruzzone.i@gmail.com>
This commit is contained in:
FedericoBruzzone 2025-02-02 11:46:21 +01:00
parent 9e48dfe5e0
commit 6e0dfc813c
5 changed files with 62 additions and 59 deletions
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42
compiler/rustc_const_eval/src/const_eval/valtrees.rs
View file

@ -273,59 +273,63 @@ pub(crate) fn eval_to_valtree<'tcx>(
/// Converts a `ValTree` to a `ConstValue`, which is needed after mir
/// construction has finished.
// FIXME(valtrees): Merge `valtree_to_const_value` and `valtree_into_mplace` into one function
// FIXME(valtrees): Accept `ty::Value` instead of `Ty` and `ty::ValTree` separately.
#[instrument(skip(tcx), level = "debug", ret)]
pub fn valtree_to_const_value<'tcx>(
tcx: TyCtxt<'tcx>,
typing_env: ty::TypingEnv<'tcx>,
ty: Ty<'tcx>,
valtree: ty::ValTree<'tcx>,
cv: ty::Value<'tcx>,
) -> mir::ConstValue<'tcx> {
// Basic idea: We directly construct `Scalar` values from trivial `ValTree`s
// (those for constants with type bool, int, uint, float or char).
// For all other types we create an `MPlace` and fill that by walking
// the `ValTree` and using `place_projection` and `place_field` to
// create inner `MPlace`s which are filled recursively.
// FIXME Does this need an example?
match *ty.kind() {
// FIXME: Does this need an example?
match *cv.ty.kind() {
ty::FnDef(..) => {
assert!(valtree.unwrap_branch().is_empty());
assert!(cv.valtree.unwrap_branch().is_empty());
mir::ConstValue::ZeroSized
}
ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char | ty::RawPtr(_, _) => {
match valtree {
match cv.valtree {
ty::ValTree::Leaf(scalar_int) => mir::ConstValue::Scalar(Scalar::Int(scalar_int)),
ty::ValTree::Branch(_) => bug!(
"ValTrees for Bool, Int, Uint, Float, Char or RawPtr should have the form ValTree::Leaf"
),
}
}
ty::Pat(ty, _) => valtree_to_const_value(tcx, typing_env, ty, valtree),
ty::Pat(ty, _) => {
let cv = ty::Value { valtree: cv.valtree, ty };
valtree_to_const_value(tcx, typing_env, cv)
}
ty::Ref(_, inner_ty, _) => {
let mut ecx =
mk_eval_cx_to_read_const_val(tcx, DUMMY_SP, typing_env, CanAccessMutGlobal::No);
let imm = valtree_to_ref(&mut ecx, valtree, inner_ty);
let imm =
ImmTy::from_immediate(imm, tcx.layout_of(typing_env.as_query_input(ty)).unwrap());
let imm = valtree_to_ref(&mut ecx, cv.valtree, inner_ty);
let imm = ImmTy::from_immediate(
imm,
tcx.layout_of(typing_env.as_query_input(cv.ty)).unwrap(),
);
op_to_const(&ecx, &imm.into(), /* for diagnostics */ false)
}
ty::Tuple(_) | ty::Array(_, _) | ty::Adt(..) => {
let layout = tcx.layout_of(typing_env.as_query_input(ty)).unwrap();
let layout = tcx.layout_of(typing_env.as_query_input(cv.ty)).unwrap();
if layout.is_zst() {
// Fast path to avoid some allocations.
return mir::ConstValue::ZeroSized;
}
if layout.backend_repr.is_scalar()
&& (matches!(ty.kind(), ty::Tuple(_))
|| matches!(ty.kind(), ty::Adt(def, _) if def.is_struct()))
&& (matches!(cv.ty.kind(), ty::Tuple(_))
|| matches!(cv.ty.kind(), ty::Adt(def, _) if def.is_struct()))
{
// A Scalar tuple/struct; we can avoid creating an allocation.
let branches = valtree.unwrap_branch();
let branches = cv.valtree.unwrap_branch();
// Find the non-ZST field. (There can be aligned ZST!)
for (i, &inner_valtree) in branches.iter().enumerate() {
let field = layout.field(&LayoutCx::new(tcx, typing_env), i);
if !field.is_zst() {
return valtree_to_const_value(tcx, typing_env, field.ty, inner_valtree);
let cv = ty::Value { valtree: inner_valtree, ty: field.ty };
return valtree_to_const_value(tcx, typing_env, cv);
}
}
bug!("could not find non-ZST field during in {layout:#?}");
@ -335,9 +339,9 @@ pub fn valtree_to_const_value<'tcx>(
mk_eval_cx_to_read_const_val(tcx, DUMMY_SP, typing_env, CanAccessMutGlobal::No);
// Need to create a place for this valtree.
let place = create_valtree_place(&mut ecx, layout, valtree);
let place = create_valtree_place(&mut ecx, layout, cv.valtree);
valtree_into_mplace(&mut ecx, &place, valtree);
valtree_into_mplace(&mut ecx, &place, cv.valtree);
dump_place(&ecx, &place);
intern_const_alloc_recursive(&mut ecx, InternKind::Constant, &place).unwrap();
@ -362,7 +366,7 @@ pub fn valtree_to_const_value<'tcx>(
| ty::Slice(_)
| ty::Dynamic(..)
| ty::UnsafeBinder(_) => {
bug!("no ValTree should have been created for type {:?}", ty.kind())
bug!("no ValTree should have been created for type {:?}", cv.ty.kind())
}
}
}

10
compiler/rustc_const_eval/src/lib.rs
View file

@ -46,14 +46,8 @@ pub fn provide(providers: &mut Providers) {
};
providers.hooks.try_destructure_mir_constant_for_user_output =
const_eval::try_destructure_mir_constant_for_user_output;
providers.valtree_to_const_val = |tcx, cv| {
const_eval::valtree_to_const_value(
tcx,
ty::TypingEnv::fully_monomorphized(),
cv.ty,
cv.valtree,
)
};
providers.valtree_to_const_val =
|tcx, cv| const_eval::valtree_to_const_value(tcx, ty::TypingEnv::fully_monomorphized(), cv);
providers.check_validity_requirement = |tcx, (init_kind, param_env_and_ty)| {
util::check_validity_requirement(tcx, init_kind, param_env_and_ty)
};

11
compiler/rustc_middle/src/mir/pretty.rs
View file

@ -12,6 +12,7 @@ use rustc_middle::mir::interpret::{
use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::*;
use tracing::trace;
use ty::print::PrettyPrinter;
use super::graphviz::write_mir_fn_graphviz;
use crate::mir::interpret::ConstAllocation;
@ -1429,10 +1430,10 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
})
};
// FIXME: call pretty_print_const_valtree?
let fmt_valtree = |valtree: &ty::ValTree<'tcx>| match valtree {
ty::ValTree::Leaf(leaf) => format!("Leaf({leaf:?})"),
ty::ValTree::Branch(_) => "Branch(..)".to_string(),
let fmt_valtree = |cv: &ty::Value<'tcx>| {
let mut cx = FmtPrinter::new(self.tcx, Namespace::ValueNS);
cx.pretty_print_const_valtree(*cv, /*print_ty*/ true).unwrap();
cx.into_buffer()
};
let val = match const_ {
@ -1442,7 +1443,7 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
format!("ty::Unevaluated({}, {:?})", self.tcx.def_path_str(uv.def), uv.args,)
}
ty::ConstKind::Value(cv) => {
format!("ty::Valtree({})", fmt_valtree(&cv.valtree))
format!("ty::Valtree({})", fmt_valtree(&cv))
}
// No `ty::` prefix since we also use this to represent errors from `mir::Unevaluated`.
ty::ConstKind::Error(_) => "Error".to_string(),

44
compiler/rustc_middle/src/ty/print/pretty.rs
View file

@ -1485,7 +1485,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
},
ty::ConstKind::Param(ParamConst { name, .. }) => p!(write("{}", name)),
ty::ConstKind::Value(cv) => {
return self.pretty_print_const_valtree(cv.valtree, cv.ty, print_ty);
return self.pretty_print_const_valtree(cv, print_ty);
}
ty::ConstKind::Bound(debruijn, bound_var) => {
@ -1785,48 +1785,49 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
Ok(())
}
// FIXME(valtrees): Accept `ty::Value` instead of `Ty` and `ty::ValTree` separately.
fn pretty_print_const_valtree(
&mut self,
valtree: ty::ValTree<'tcx>,
ty: Ty<'tcx>,
cv: ty::Value<'tcx>,
print_ty: bool,
) -> Result<(), PrintError> {
define_scoped_cx!(self);
if self.should_print_verbose() {
p!(write("ValTree({:?}: ", valtree), print(ty), ")");
p!(write("ValTree({:?}: ", cv.valtree), print(cv.ty), ")");
return Ok(());
}
let u8_type = self.tcx().types.u8;
match (valtree, ty.kind()) {
match (cv.valtree, cv.ty.kind()) {
(ty::ValTree::Branch(_), ty::Ref(_, inner_ty, _)) => match inner_ty.kind() {
ty::Slice(t) if *t == u8_type => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
let bytes =
cv.valtree.try_to_raw_bytes(self.tcx(), cv.ty).unwrap_or_else(|| {
bug!(
"expected to convert valtree {:?} to raw bytes for type {:?}",
valtree,
cv.valtree,
t
)
});
return self.pretty_print_byte_str(bytes);
}
ty::Str => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
bug!("expected to convert valtree to raw bytes for type {:?}", ty)
let bytes =
cv.valtree.try_to_raw_bytes(self.tcx(), cv.ty).unwrap_or_else(|| {
bug!("expected to convert valtree to raw bytes for type {:?}", cv.ty)
});
p!(write("{:?}", String::from_utf8_lossy(bytes)));
return Ok(());
}
_ => {
let cv = ty::Value { valtree: cv.valtree, ty: *inner_ty };
p!("&");
p!(pretty_print_const_valtree(valtree, *inner_ty, print_ty));
p!(pretty_print_const_valtree(cv, print_ty));
return Ok(());
}
},
(ty::ValTree::Branch(_), ty::Array(t, _)) if *t == u8_type => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
let bytes = cv.valtree.try_to_raw_bytes(self.tcx(), cv.ty).unwrap_or_else(|| {
bug!("expected to convert valtree to raw bytes for type {:?}", t)
});
p!("*");
@ -1835,10 +1836,13 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
}
// Aggregates, printed as array/tuple/struct/variant construction syntax.
(ty::ValTree::Branch(_), ty::Array(..) | ty::Tuple(..) | ty::Adt(..)) => {
let contents =
self.tcx().destructure_const(ty::Const::new_value(self.tcx(), valtree, ty));
let contents = self.tcx().destructure_const(ty::Const::new_value(
self.tcx(),
cv.valtree,
cv.ty,
));
let fields = contents.fields.iter().copied();
match *ty.kind() {
match *cv.ty.kind() {
ty::Array(..) => {
p!("[", comma_sep(fields), "]");
}
@ -1855,7 +1859,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
write!(this, "unreachable()")?;
Ok(())
},
|this| this.print_type(ty),
|this| this.print_type(cv.ty),
": ",
)?;
}
@ -1892,7 +1896,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
return self.pretty_print_const_scalar_int(leaf, *inner_ty, print_ty);
}
(ty::ValTree::Leaf(leaf), _) => {
return self.pretty_print_const_scalar_int(leaf, ty, print_ty);
return self.pretty_print_const_scalar_int(leaf, cv.ty, print_ty);
}
// FIXME(oli-obk): also pretty print arrays and other aggregate constants by reading
// their fields instead of just dumping the memory.
@ -1900,13 +1904,13 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
}
// fallback
if valtree == ty::ValTree::zst() {
if cv.valtree == ty::ValTree::zst() {
p!(write("<ZST>"));
} else {
p!(write("{:?}", valtree));
p!(write("{:?}", cv.valtree));
}
if print_ty {
p!(": ", print(ty));
p!(": ", print(cv.ty));
}
Ok(())
}

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

@ -170,7 +170,7 @@ impl<'tcx> fmt::Debug for ty::Const<'tcx> {
bug!("we checked that this is a valtree")
};
let mut cx = FmtPrinter::new(tcx, Namespace::ValueNS);
cx.pretty_print_const_valtree(cv.valtree, cv.ty, /*print_ty*/ true)?;
cx.pretty_print_const_valtree(cv, /*print_ty*/ true)?;
f.write_str(&cx.into_buffer())
});
}