Split out the stable part of smir into its own crate to prevent accidental usage of forever unstable things

Cargo.lock

@@ -3257,6 +3257,7 @@ dependencies = [
  "rustc_driver",
  "rustc_driver_impl",
  "rustc_smir",
+ "stable_mir",
 ]
 
 [[package]]
@@ -4421,7 +4422,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "scoped-tls",
+ "stable_mir",
  "tracing",
 ]
 
@@ -4958,6 +4959,14 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
 
+[[package]]
+name = "stable_mir"
+version = "0.1.0-preview"
+dependencies = [
+ "scoped-tls",
+ "tracing",
+]
+
 [[package]]
 name = "stacker"
 version = "0.1.15"

compiler/rustc/Cargo.toml

@@ -13,6 +13,7 @@ rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }
 # Make sure rustc_smir ends up in the sysroot, because this
 # crate is intended to be used by stable MIR consumers, which are not in-tree
 rustc_smir = { path = "../rustc_smir" }
+stable_mir = { path = "../stable_mir" }
 
 [dependencies.jemalloc-sys]
 version = "0.5.0"

compiler/rustc_smir/Cargo.toml

@@ -4,24 +4,14 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
-# Use optional dependencies for rustc_* in order to support building this crate separately.
-rustc_hir = { path = "../rustc_hir", optional = true }
-rustc_middle = { path = "../rustc_middle", optional = true }
-rustc_span = { path = "../rustc_span", optional = true }
-rustc_target = { path = "../rustc_target", optional = true }
-rustc_driver = { path = "../rustc_driver", optional = true }
-rustc_interface = { path = "../rustc_interface", optional = true}
-rustc_session = {path = "../rustc_session", optional = true}
+rustc_hir = { path = "../rustc_hir" }
+rustc_middle = { path = "../rustc_middle" }
+rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
+rustc_driver = { path = "../rustc_driver" }
+rustc_interface = { path = "../rustc_interface" }
+rustc_session = {path = "../rustc_session" }
 tracing = "0.1"
-scoped-tls = "1.0"
+stable_mir = {path = "../stable_mir" }
 
 [features]
-default = [
-    "rustc_hir",
-    "rustc_middle",
-    "rustc_span",
-    "rustc_target",
-    "rustc_driver",
-    "rustc_interface",
-    "rustc_session",
-]

compiler/rustc_smir/src/lib.rs

@@ -10,26 +10,12 @@
     html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(attr(allow(unused_variables), deny(warnings)))
 )]
-#![cfg_attr(not(feature = "default"), feature(rustc_private))]
+#![feature(rustc_private)]
 #![feature(ptr_metadata)]
 #![feature(type_alias_impl_trait)] // Used to define opaque types.
 #![feature(intra_doc_pointers)]
 
-// Declare extern rustc_* crates to enable building this crate separately from the compiler.
-#[cfg(not(feature = "default"))]
-extern crate rustc_hir;
-#[cfg(not(feature = "default"))]
-extern crate rustc_middle;
-#[cfg(not(feature = "default"))]
-extern crate rustc_span;
-#[cfg(not(feature = "default"))]
-extern crate rustc_target;
-
 pub mod rustc_internal;
-pub mod stable_mir;
 
 // Make this module private for now since external users should not call these directly.
 mod rustc_smir;
-
-#[macro_use]
-extern crate scoped_tls;

compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -6,14 +6,14 @@
 use std::ops::{ControlFlow, Index};
 
 use crate::rustc_internal;
-use crate::stable_mir::CompilerError;
-use crate::{rustc_smir::Tables, stable_mir};
+use crate::rustc_smir::Tables;
 use rustc_driver::{Callbacks, Compilation, RunCompiler};
 use rustc_interface::{interface, Queries};
 use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::ty::TyCtxt;
 pub use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Span;
+use stable_mir::CompilerError;
 
 impl<'tcx> Index<stable_mir::DefId> for Tables<'tcx> {
     type Output = DefId;
@@ -129,7 +129,7 @@ pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
 }
 
 pub fn run(tcx: TyCtxt<'_>, f: impl FnOnce()) {
-    crate::stable_mir::run(
+    stable_mir::run(
         Tables { tcx, def_ids: vec![], alloc_ids: vec![], spans: vec![], types: vec![] },
         f,
     );

compiler/rustc_smir/src/rustc_smir/alloc.rs

@@ -3,11 +3,9 @@ use rustc_middle::mir::{
     ConstValue,
 };
 
-use crate::{
-    rustc_smir::{Stable, Tables},
-    stable_mir::mir::Mutability,
-    stable_mir::ty::{Allocation, ProvenanceMap},
-};
+use crate::rustc_smir::{Stable, Tables};
+use stable_mir::mir::Mutability;
+use stable_mir::ty::{Allocation, ProvenanceMap};
 
 /// Creates new empty `Allocation` from given `Align`.
 fn new_empty_allocation(align: rustc_target::abi::Align) -> Allocation {

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -7,19 +7,16 @@
 //!
 //! For now, we are developing everything inside `rustc`, thus, we keep this module private.
 
-use crate::stable_mir::mir::{CopyNonOverlapping, UserTypeProjection, VariantIdx};
-use crate::stable_mir::ty::{
-    FloatTy, GenericParamDef, IntTy, Movability, RigidTy, Span, TyKind, UintTy,
-};
-use crate::stable_mir::{self, opaque, CompilerError, Context};
 use hir::def::DefKind;
 use rustc_hir as hir;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{alloc_range, AllocId};
 use rustc_middle::ty::{self, Ty, TyCtxt, Variance};
 use rustc_span::def_id::{CrateNum, DefId, LOCAL_CRATE};
-use rustc_span::ErrorGuaranteed;
 use rustc_target::abi::FieldIdx;
+use stable_mir::mir::{CopyNonOverlapping, UserTypeProjection, VariantIdx};
+use stable_mir::ty::{FloatTy, GenericParamDef, IntTy, Movability, RigidTy, Span, TyKind, UintTy};
+use stable_mir::{self, opaque, Context};
 use tracing::debug;
 
 mod alloc;
@@ -112,7 +109,7 @@ impl<'tcx> Context for Tables<'tcx> {
         }
     }
 
-    fn ty_kind(&mut self, ty: crate::stable_mir::ty::Ty) -> TyKind {
+    fn ty_kind(&mut self, ty: stable_mir::ty::Ty) -> TyKind {
         self.types[ty.0].clone().stable(self)
     }
 
@@ -1517,12 +1514,6 @@ impl<'tcx> Stable<'tcx> for rustc_span::Span {
     }
 }
 
-impl<T> From<ErrorGuaranteed> for CompilerError<T> {
-    fn from(_error: ErrorGuaranteed) -> Self {
-        CompilerError::CompilationFailed
-    }
-}
-
 impl<'tcx> Stable<'tcx> for DefKind {
     type T = stable_mir::DefKind;
 

compiler/stable_mir/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "stable_mir"
+version = "0.1.0-preview"
+edition = "2021"
+
+[dependencies]
+tracing = "0.1"
+scoped-tls = "1.0"

compiler/stable_mir/src/fold.rs

@@ -1,11 +1,10 @@
 use std::ops::ControlFlow;
 
-use super::{
-    ty::{
-        Allocation, Binder, Const, ConstDef, ConstantKind, ExistentialPredicate, FnSig,
-        GenericArgKind, GenericArgs, Promoted, RigidTy, TermKind, Ty, TyKind, UnevaluatedConst,
-    },
-    Opaque,
+use crate::Opaque;
+
+use super::ty::{
+    Allocation, Binder, Const, ConstDef, ConstantKind, ExistentialPredicate, FnSig, GenericArgKind,
+    GenericArgs, Promoted, RigidTy, TermKind, Ty, TyKind, UnevaluatedConst,
 };
 
 pub trait Folder: Sized {

compiler/stable_mir/src/lib.rs

@@ -1,15 +1,21 @@
-//! Module that implements the public interface to the Stable MIR.
+//! The WIP stable interface to rustc internals.
 //!
-//! This module shall contain all type definitions and APIs that we expect third-party tools to invoke to
+//! For more information see <https://github.com/rust-lang/project-stable-mir>
+//!
+//! # Note
+//!
+//! This API is still completely unstable and subject to change.
+
+#![doc(
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
+    test(attr(allow(unused_variables), deny(warnings)))
+)]
+//!
+//! This crate shall contain all type definitions and APIs that we expect third-party tools to invoke to
 //! interact with the compiler.
 //!
-//! The goal is to eventually move this module to its own crate which shall be published on
+//! The goal is to eventually be published on
 //! [crates.io](https://crates.io).
-//!
-//! ## Note:
-//!
-//! There shouldn't be any direct references to internal compiler constructs in this module.
-//! If you need an internal construct, consider using `rustc_internal` or `rustc_smir`.
 
 use std::cell::Cell;
 use std::fmt;
@@ -19,6 +25,9 @@ use self::ty::{
     GenericPredicates, Generics, ImplDef, ImplTrait, Span, TraitDecl, TraitDef, Ty, TyKind,
 };
 
+#[macro_use]
+extern crate scoped_tls;
+
 pub mod fold;
 pub mod mir;
 pub mod ty;
@@ -32,11 +41,11 @@ pub type CrateNum = usize;
 
 /// A unique identification number for each item accessible for the current compilation unit.
 #[derive(Clone, Copy, PartialEq, Eq)]
-pub struct DefId(pub(crate) usize);
+pub struct DefId(pub usize);
 
 impl Debug for DefId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("DefId:")
+        f.debug_struct("DefId")
             .field("id", &self.0)
             .field("name", &with(|cx| cx.name_of_def_id(*self)))
             .finish()
@@ -45,7 +54,7 @@ impl Debug for DefId {
 
 /// A unique identification number for each provenance
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct AllocId(pub(crate) usize);
+pub struct AllocId(pub usize);
 
 /// A list of crate items.
 pub type CrateItems = Vec<CrateItem>;
@@ -73,7 +82,7 @@ pub enum CompilerError<T> {
 /// Holds information about a crate.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Crate {
-    pub(crate) id: CrateNum,
+    pub id: CrateNum,
     pub name: Symbol,
     pub is_local: bool,
 }
@@ -84,7 +93,7 @@ pub type DefKind = Opaque;
 /// For now, it only stores the item DefId. Use functions inside `rustc_internal` module to
 /// use this item.
 #[derive(Clone, PartialEq, Eq, Debug)]
-pub struct CrateItem(pub(crate) DefId);
+pub struct CrateItem(pub DefId);
 
 impl CrateItem {
     pub fn body(&self) -> mir::Body {
@@ -170,9 +179,12 @@ pub trait Context {
     /// Prints the name of given `DefId`
     fn name_of_def_id(&self, def_id: DefId) -> String;
 
+    /// Prints a human readable form of `Span`
     fn print_span(&self, span: Span) -> String;
 
+    /// Prints the kind of given `DefId`
     fn def_kind(&mut self, def_id: DefId) -> DefKind;
+
     /// `Span` of an item
     fn span_of_an_item(&mut self, def_id: DefId) -> Span;
 
@@ -200,7 +212,7 @@ pub fn run(mut context: impl Context, f: impl FnOnce()) {
 
 /// Loads the current context and calls a function with it.
 /// Do not nest these, as that will ICE.
-pub(crate) fn with<R>(f: impl FnOnce(&mut dyn Context) -> R) -> R {
+pub fn with<R>(f: impl FnOnce(&mut dyn Context) -> R) -> R {
     assert!(TLV.is_set());
     TLV.with(|tlv| {
         let ptr = tlv.get();
@@ -225,6 +237,6 @@ impl std::fmt::Debug for Opaque {
     }
 }
 
-pub(crate) fn opaque<T: Debug>(value: &T) -> Opaque {
+pub fn opaque<T: Debug>(value: &T) -> Opaque {
     Opaque(format!("{value:?}"))
 }

compiler/stable_mir/src/mir/body.rs

@@ -1,8 +1,6 @@
-use crate::stable_mir::ty::{
-    AdtDef, ClosureDef, Const, GeneratorDef, GenericArgs, Movability, Region,
-};
-use crate::stable_mir::Opaque;
-use crate::stable_mir::{self, ty::Ty, Span};
+use crate::ty::{AdtDef, ClosureDef, Const, GeneratorDef, GenericArgs, Movability, Region};
+use crate::Opaque;
+use crate::{ty::Ty, Span};
 
 #[derive(Clone, Debug)]
 pub struct Body {
@@ -135,7 +133,7 @@ pub enum AsyncGeneratorKind {
 }
 
 pub(crate) type LocalDefId = Opaque;
-/// [`rustc_middle::mir::Coverage`] is heavily tied to internal details of the
+/// The rustc coverage data structures are heavily tied to internal details of the
 /// coverage implementation that are likely to change, and are unlikely to be
 /// useful to third-party tools for the foreseeable future.
 pub(crate) type Coverage = Opaque;
@@ -215,7 +213,7 @@ pub enum Rvalue {
     /// generator lowering, `Generator` aggregate kinds are disallowed too.
     Aggregate(AggregateKind, Vec<Operand>),
 
-    /// * `Offset` has the same semantics as [`offset`](pointer::offset), except that the second
+    /// * `Offset` has the same semantics as `<*const T>::offset`, except that the second
     ///   parameter may be a `usize` as well.
     /// * The comparison operations accept `bool`s, `char`s, signed or unsigned integers, floats,
     ///   raw pointers, or function pointers and return a `bool`. The types of the operands must be
@@ -245,16 +243,14 @@ pub enum Rvalue {
     /// deref operation, immediately followed by one or more projections.
     CopyForDeref(Place),
 
-    /// Computes the discriminant of the place, returning it as an integer of type
-    /// [`discriminant_ty`]. Returns zero for types without discriminant.
+    /// Computes the discriminant of the place, returning it as an integer.
+    /// Returns zero for types without discriminant.
     ///
     /// The validity requirements for the underlying value are undecided for this rvalue, see
     /// [#91095]. Note too that the value of the discriminant is not the same thing as the
-    /// variant index; use [`discriminant_for_variant`] to convert.
+    /// variant index;
     ///
-    /// [`discriminant_ty`]: rustc_middle::ty::Ty::discriminant_ty
     /// [#91095]: https://github.com/rust-lang/rust/issues/91095
-    /// [`discriminant_for_variant`]: rustc_middle::ty::Ty::discriminant_for_variant
     Discriminant(Place),
 
     /// Yields the length of the place, as a `usize`.
@@ -295,7 +291,7 @@ pub enum Rvalue {
     ///
     /// **Needs clarification**: Are there weird additional semantics here related to the runtime
     /// nature of this operation?
-    ThreadLocalRef(stable_mir::CrateItem),
+    ThreadLocalRef(crate::CrateItem),
 
     /// Computes a value as described by the operation.
     NullaryOp(NullOp, Ty),

compiler/stable_mir/src/ty.rs

@@ -1,8 +1,9 @@
 use super::{
     mir::Safety,
     mir::{Body, Mutability},
-    with, AllocId, DefId, Opaque,
+    with, AllocId, DefId,
 };
+use crate::Opaque;
 use std::fmt::{self, Debug, Formatter};
 
 #[derive(Copy, Clone)]
@@ -33,9 +34,9 @@ pub struct Const {
 }
 
 type Ident = Opaque;
-pub(crate) type Region = Opaque;
+pub type Region = Opaque;
 #[derive(Clone, Copy, PartialEq, Eq)]
-pub struct Span(pub(crate) usize);
+pub struct Span(pub usize);
 
 impl Debug for Span {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
@@ -110,10 +111,10 @@ pub enum Movability {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct ForeignDef(pub(crate) DefId);
+pub struct ForeignDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct FnDef(pub(crate) DefId);
+pub struct FnDef(pub DefId);
 
 impl FnDef {
     pub fn body(&self) -> Body {
@@ -122,34 +123,34 @@ impl FnDef {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct ClosureDef(pub(crate) DefId);
+pub struct ClosureDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct GeneratorDef(pub(crate) DefId);
+pub struct GeneratorDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct ParamDef(pub(crate) DefId);
+pub struct ParamDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct BrNamedDef(pub(crate) DefId);
+pub struct BrNamedDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct AdtDef(pub(crate) DefId);
+pub struct AdtDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct AliasDef(pub(crate) DefId);
+pub struct AliasDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct TraitDef(pub(crate) DefId);
+pub struct TraitDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct GenericDef(pub(crate) DefId);
+pub struct GenericDef(pub DefId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct ConstDef(pub(crate) DefId);
+pub struct ConstDef(pub DefId);
 
 #[derive(Clone, PartialEq, Eq, Debug)]
-pub struct ImplDef(pub(crate) DefId);
+pub struct ImplDef(pub DefId);
 
 #[derive(Clone, Debug)]
 pub struct GenericArgs(pub Vec<GenericArgKind>);
@@ -333,7 +334,7 @@ pub type Bytes = Vec<Option<u8>>;
 pub type Size = usize;
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct Prov(pub(crate) AllocId);
+pub struct Prov(pub AllocId);
 pub type Align = u64;
 pub type Promoted = u32;
 pub type InitMaskMaterialized = Vec<u64>;

compiler/stable_mir/src/visitor.rs

@@ -1,11 +1,10 @@
 use std::ops::ControlFlow;
 
-use super::{
-    ty::{
-        Allocation, Binder, Const, ConstDef, ExistentialPredicate, FnSig, GenericArgKind,
-        GenericArgs, Promoted, RigidTy, TermKind, Ty, UnevaluatedConst,
-    },
-    Opaque,
+use crate::Opaque;
+
+use super::ty::{
+    Allocation, Binder, Const, ConstDef, ExistentialPredicate, FnSig, GenericArgKind, GenericArgs,
+    Promoted, RigidTy, TermKind, Ty, UnevaluatedConst,
 };
 
 pub trait Visitor: Sized {

src/bootstrap/compile.rs

@@ -1789,7 +1789,10 @@ pub fn run_cargo(
                 // During check builds we need to keep crate metadata
                 keep = true;
             } else if rlib_only_metadata {
-                if filename.contains("jemalloc_sys") || filename.contains("rustc_smir") {
+                if filename.contains("jemalloc_sys")
+                    || filename.contains("rustc_smir")
+                    || filename.contains("stable_mir")
+                {
                     // jemalloc_sys and rustc_smir are not linked into librustc_driver.so,
                     // so we need to distribute them as rlib to be able to use them.
                     keep |= filename.ends_with(".rlib");

tests/ui-fulldeps/stable-mir/compilation-result.rs

@@ -11,9 +11,10 @@
 
 extern crate rustc_middle;
 extern crate rustc_smir;
+extern crate stable_mir;
 
 use rustc_middle::ty::TyCtxt;
-use rustc_smir::{rustc_internal, stable_mir};
+use rustc_smir::rustc_internal;
 use std::io::Write;
 use std::ops::ControlFlow;
 

tests/ui-fulldeps/stable-mir/crate-info.rs

@@ -13,13 +13,13 @@
 extern crate rustc_hir;
 extern crate rustc_middle;
 extern crate rustc_smir;
+extern crate stable_mir;
 
 use rustc_hir::def::DefKind;
 use rustc_middle::ty::TyCtxt;
-use rustc_smir::{
-    rustc_internal,
-    stable_mir::{self, fold::Foldable},
-};
+use rustc_smir::rustc_internal;
+
+use stable_mir::fold::Foldable;
 use std::assert_matches::assert_matches;
 use std::io::Write;
 use std::ops::ControlFlow;

triagebot.toml

@@ -542,6 +542,10 @@ cc = ["@davidtwco", "@compiler-errors", "@JohnTitor", "@TaKO8Ki"]
 message = "This PR changes Stable MIR"
 cc = ["@oli-obk", "@celinval", "@spastorino"]
 
+[mentions."compiler/stable_mir"]
+message = "This PR changes Stable MIR"
+cc = ["@oli-obk", "@celinval", "@spastorino"]
+
 [mentions."compiler/rustc_target/src/spec"]
 message = """
 These commits modify **compiler targets**.