Rollup merge of rust-lang#118927 - celinval:smir-missing-info, r=compiler-errors

Erase late bound regions from `Instance::fn_sig()` and add a few more details to StableMIR APIs

The Instance `fn_sig()` still included a late bound regions which needed a new compiler function in order to be erased. I've also bundled the following small fixes in this PR, let me know if you want me to isolate any of them.

  - Add missing `CoroutineKind::AsyncGen`.
  - Add optional spread argument to function body which is needed to properly analyze compiler shims.
  - Add a utility method to iterate over all locals together with their declaration.
  - Add a method to get the description of `AssertMessage`*.

* For the last one, we could consider eventually calling the internal `AssertKind::description()` to avoid code duplication. However, we still don't have ways to convert `AssertMessage`, `Operand`, `Place` and others, in order to use that. The other downside of using the internal method is that it will panic for some of the variants.

r ? `@ouz-a`

Author: aliemjay

compiler/rustc_smir/src/rustc_smir/context.rs

@@ -5,7 +5,9 @@
 
 use rustc_middle::ty;
 use rustc_middle::ty::print::{with_forced_trimmed_paths, with_no_trimmed_paths};
-use rustc_middle::ty::{GenericPredicates, Instance, ParamEnv, ScalarInt, ValTree};
+use rustc_middle::ty::{
+    GenericPredicates, Instance, ParamEnv, ScalarInt, TypeVisitableExt, ValTree,
+};
 use rustc_span::def_id::LOCAL_CRATE;
 use stable_mir::compiler_interface::Context;
 use stable_mir::mir::alloc::GlobalAlloc;
@@ -324,7 +326,8 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
     fn instance_ty(&self, def: InstanceDef) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
         let instance = tables.instances[def];
-        instance.ty(tables.tcx, ParamEnv::empty()).stable(&mut *tables)
+        assert!(!instance.has_non_region_param(), "{instance:?} needs further substitution");
+        instance.ty(tables.tcx, ParamEnv::reveal_all()).stable(&mut *tables)
     }
 
     fn instance_def_id(&self, def: InstanceDef) -> stable_mir::DefId {

compiler/rustc_smir/src/rustc_smir/convert/mir.rs

@@ -36,6 +36,7 @@ impl<'tcx> Stable<'tcx> for mir::Body<'tcx> {
                 .collect(),
             self.arg_count,
             self.var_debug_info.iter().map(|info| info.stable(tables)).collect(),
+            self.spread_arg.stable(tables),
         )
     }
 }

compiler/rustc_smir/src/rustc_smir/convert/mod.rs

@@ -57,7 +57,9 @@ impl<'tcx> Stable<'tcx> for rustc_hir::CoroutineKind {
                 stable_mir::mir::CoroutineKind::Gen(source.stable(tables))
             }
             CoroutineKind::Coroutine => stable_mir::mir::CoroutineKind::Coroutine,
-            CoroutineKind::AsyncGen(_) => todo!(),
+            CoroutineKind::AsyncGen(source) => {
+                stable_mir::mir::CoroutineKind::AsyncGen(source.stable(tables))
+            }
         }
     }
 }

compiler/stable_mir/src/mir/body.rs

@@ -22,6 +22,11 @@ pub struct Body {
 
     /// Debug information pertaining to user variables, including captures.
     pub var_debug_info: Vec<VarDebugInfo>,
+
+    /// Mark an argument (which must be a tuple) as getting passed as its individual components.
+    ///
+    /// This is used for the "rust-call" ABI such as closures.
+    pub(super) spread_arg: Option<Local>,
 }
 
 pub type BasicBlockIdx = usize;
@@ -36,14 +41,15 @@ impl Body {
         locals: LocalDecls,
         arg_count: usize,
         var_debug_info: Vec<VarDebugInfo>,
+        spread_arg: Option<Local>,
     ) -> Self {
         // If locals doesn't contain enough entries, it can lead to panics in
         // `ret_local`, `arg_locals`, and `inner_locals`.
         assert!(
             locals.len() > arg_count,
             "A Body must contain at least a local for the return value and each of the function's arguments"
         );
-        Self { blocks, locals, arg_count, var_debug_info }
+        Self { blocks, locals, arg_count, var_debug_info, spread_arg }
     }
 
     /// Return local that holds this function's return value.
@@ -75,6 +81,11 @@ impl Body {
         self.locals.get(local)
     }
 
+    /// Get an iterator for all local declarations.
+    pub fn local_decls(&self) -> impl Iterator<Item = (Local, &LocalDecl)> {
+        self.locals.iter().enumerate()
+    }
+
     pub fn dump<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
         writeln!(w, "{}", function_body(self))?;
         self.blocks
@@ -98,6 +109,10 @@ impl Body {
             .collect::<Result<Vec<_>, _>>()?;
         Ok(())
     }
+
+    pub fn spread_arg(&self) -> Option<Local> {
+        self.spread_arg
+    }
 }
 
 type LocalDecls = Vec<LocalDecl>;
@@ -248,6 +263,57 @@ pub enum AssertMessage {
     MisalignedPointerDereference { required: Operand, found: Operand },
 }
 
+impl AssertMessage {
+    pub fn description(&self) -> Result<&'static str, Error> {
+        match self {
+            AssertMessage::Overflow(BinOp::Add, _, _) => Ok("attempt to add with overflow"),
+            AssertMessage::Overflow(BinOp::Sub, _, _) => Ok("attempt to subtract with overflow"),
+            AssertMessage::Overflow(BinOp::Mul, _, _) => Ok("attempt to multiply with overflow"),
+            AssertMessage::Overflow(BinOp::Div, _, _) => Ok("attempt to divide with overflow"),
+            AssertMessage::Overflow(BinOp::Rem, _, _) => {
+                Ok("attempt to calculate the remainder with overflow")
+            }
+            AssertMessage::OverflowNeg(_) => Ok("attempt to negate with overflow"),
+            AssertMessage::Overflow(BinOp::Shr, _, _) => Ok("attempt to shift right with overflow"),
+            AssertMessage::Overflow(BinOp::Shl, _, _) => Ok("attempt to shift left with overflow"),
+            AssertMessage::Overflow(op, _, _) => Err(error!("`{:?}` cannot overflow", op)),
+            AssertMessage::DivisionByZero(_) => Ok("attempt to divide by zero"),
+            AssertMessage::RemainderByZero(_) => {
+                Ok("attempt to calculate the remainder with a divisor of zero")
+            }
+            AssertMessage::ResumedAfterReturn(CoroutineKind::Coroutine) => {
+                Ok("coroutine resumed after completion")
+            }
+            AssertMessage::ResumedAfterReturn(CoroutineKind::Async(_)) => {
+                Ok("`async fn` resumed after completion")
+            }
+            AssertMessage::ResumedAfterReturn(CoroutineKind::Gen(_)) => {
+                Ok("`async gen fn` resumed after completion")
+            }
+            AssertMessage::ResumedAfterReturn(CoroutineKind::AsyncGen(_)) => {
+                Ok("`gen fn` should just keep returning `AssertMessage::None` after completion")
+            }
+            AssertMessage::ResumedAfterPanic(CoroutineKind::Coroutine) => {
+                Ok("coroutine resumed after panicking")
+            }
+            AssertMessage::ResumedAfterPanic(CoroutineKind::Async(_)) => {
+                Ok("`async fn` resumed after panicking")
+            }
+            AssertMessage::ResumedAfterPanic(CoroutineKind::Gen(_)) => {
+                Ok("`async gen fn` resumed after panicking")
+            }
+            AssertMessage::ResumedAfterPanic(CoroutineKind::AsyncGen(_)) => {
+                Ok("`gen fn` should just keep returning `AssertMessage::None` after panicking")
+            }
+
+            AssertMessage::BoundsCheck { .. } => Ok("index out of bounds"),
+            AssertMessage::MisalignedPointerDereference { .. } => {
+                Ok("misaligned pointer dereference")
+            }
+        }
+    }
+}
+
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum BinOp {
     Add,
@@ -325,6 +391,7 @@ pub enum CoroutineKind {
     Async(CoroutineSource),
     Coroutine,
     Gen(CoroutineSource),
+    AsyncGen(CoroutineSource),
 }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]

compiler/stable_mir/src/mir/mono.rs

@@ -1,6 +1,6 @@
 use crate::crate_def::CrateDef;
 use crate::mir::Body;
-use crate::ty::{Allocation, ClosureDef, ClosureKind, FnDef, FnSig, GenericArgs, IndexedVal, Ty};
+use crate::ty::{Allocation, ClosureDef, ClosureKind, FnDef, GenericArgs, IndexedVal, Ty};
 use crate::{with, CrateItem, DefId, Error, ItemKind, Opaque, Symbol};
 use std::fmt::{Debug, Formatter};
 
@@ -115,11 +115,6 @@ impl Instance {
         })
     }
 
-    /// Get this function signature with all types already instantiated.
-    pub fn fn_sig(&self) -> FnSig {
-        self.ty().kind().fn_sig().unwrap().skip_binder()
-    }
-
     /// Check whether this instance is an empty shim.
     ///
     /// Allow users to check if this shim can be ignored when called directly.

compiler/stable_mir/src/mir/pretty.rs

@@ -260,6 +260,7 @@ pub fn pretty_assert_message(msg: &AssertMessage) -> String {
             );
             pretty
         }
+        AssertMessage::Overflow(op, _, _) => unreachable!("`{:?}` cannot overflow", op),
         AssertMessage::OverflowNeg(op) => {
             let pretty_op = pretty_operand(op);
             pretty.push_str(
@@ -279,17 +280,15 @@ pub fn pretty_assert_message(msg: &AssertMessage) -> String {
             );
             pretty
         }
-        AssertMessage::ResumedAfterReturn(_) => {
-            format!("attempt to resume a generator after completion")
-        }
-        AssertMessage::ResumedAfterPanic(_) => format!("attempt to resume a panicked generator"),
         AssertMessage::MisalignedPointerDereference { required, found } => {
             let pretty_required = pretty_operand(required);
             let pretty_found = pretty_operand(found);
             pretty.push_str(format!("\"misaligned pointer dereference: address must be a multiple of {{}} but is {{}}\",{pretty_required}, {pretty_found}").as_str());
             pretty
         }
-        _ => todo!(),
+        AssertMessage::ResumedAfterReturn(_) | AssertMessage::ResumedAfterPanic(_) => {
+            msg.description().unwrap().to_string()
+        }
     }
 }
 

compiler/stable_mir/src/mir/visit.rs

@@ -133,7 +133,7 @@ pub trait MirVisitor {
     }
 
     fn super_body(&mut self, body: &Body) {
-        let Body { blocks, locals: _, arg_count, var_debug_info } = body;
+        let Body { blocks, locals: _, arg_count, var_debug_info, spread_arg: _ } = body;
 
         for bb in blocks {
             self.visit_basic_block(bb);

compiler/stable_mir/src/ty.rs

@@ -22,9 +22,7 @@ impl Debug for Ty {
 /// Constructors for `Ty`.
 impl Ty {
     /// Create a new type from a given kind.
-    ///
-    /// Note that not all types may be supported at this point.
-    fn from_rigid_kind(kind: RigidTy) -> Ty {
+    pub fn from_rigid_kind(kind: RigidTy) -> Ty {
         with(|cx| cx.new_rigid_ty(kind))
     }
 
@@ -77,6 +75,16 @@ impl Ty {
     pub fn bool_ty() -> Ty {
         Ty::from_rigid_kind(RigidTy::Bool)
     }
+
+    /// Create a type representing a signed integer.
+    pub fn signed_ty(inner: IntTy) -> Ty {
+        Ty::from_rigid_kind(RigidTy::Int(inner))
+    }
+
+    /// Create a type representing an unsigned integer.
+    pub fn unsigned_ty(inner: UintTy) -> Ty {
+        Ty::from_rigid_kind(RigidTy::Uint(inner))
+    }
 }
 
 impl Ty {

tests/ui-fulldeps/stable-mir/check_defs.rs

@@ -69,7 +69,7 @@ fn extract_elem_ty(ty: Ty) -> Ty {
 
 /// Check signature and type of `Vec::<u8>::new` and its generic version.
 fn test_vec_new(instance: mir::mono::Instance) {
-    let sig = instance.fn_sig();
+    let sig = instance.ty().kind().fn_sig().unwrap().skip_binder();
     assert_matches!(sig.inputs(), &[]);
     let elem_ty = extract_elem_ty(sig.output());
     assert_matches!(elem_ty.kind(), TyKind::RigidTy(RigidTy::Uint(UintTy::U8)));