Add common trait for crate definitions

compiler/rustc_smir/src/rustc_internal/internal.rs

@@ -11,8 +11,8 @@ use stable_mir::mir::alloc::AllocId;
 use stable_mir::mir::mono::{Instance, MonoItem, StaticDef};
 use stable_mir::ty::{
     AdtDef, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind, Const,
-    ExistentialTraitRef, FloatTy, GenericArgKind, GenericArgs, IntTy, Region, RigidTy, TraitRef,
-    Ty, UintTy,
+    ExistentialTraitRef, FloatTy, GenericArgKind, GenericArgs, IntTy, Region, RigidTy, Span,
+    TraitRef, Ty, UintTy,
 };
 use stable_mir::{CrateItem, DefId};
 
@@ -279,6 +279,14 @@ impl<'tcx> RustcInternal<'tcx> for AdtDef {
     }
 }
 
+impl<'tcx> RustcInternal<'tcx> for Span {
+    type T = rustc_span::Span;
+
+    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        tables[*self]
+    }
+}
+
 impl<'tcx, T> RustcInternal<'tcx> for &T
 where
     T: RustcInternal<'tcx>,

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -14,6 +14,7 @@ use rustc_hir::def::DefKind;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{alloc_range, AllocId};
 use rustc_middle::mir::mono::MonoItem;
+use rustc_middle::ty::print::{with_forced_trimmed_paths, with_no_trimmed_paths};
 use rustc_middle::ty::{self, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, Variance};
 use rustc_span::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_target::abi::FieldIdx;
@@ -28,7 +29,7 @@ use stable_mir::ty::{
     EarlyParamRegion, FloatTy, FnDef, GenericArgs, GenericParamDef, IntTy, LineInfo, Movability,
     RigidTy, Span, TyKind, UintTy,
 };
-use stable_mir::{self, opaque, Context, CrateItem, Error, Filename, ItemKind};
+use stable_mir::{self, opaque, Context, Crate, CrateItem, Error, Filename, ItemKind, Symbol};
 use std::cell::RefCell;
 use tracing::debug;
 
@@ -61,9 +62,18 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         crates
     }
 
-    fn name_of_def_id(&self, def_id: stable_mir::DefId) -> String {
+    fn def_name(&self, def_id: stable_mir::DefId, trimmed: bool) -> Symbol {
         let tables = self.0.borrow();
-        tables.tcx.def_path_str(tables[def_id])
+        if trimmed {
+            with_forced_trimmed_paths!(tables.tcx.def_path_str(tables[def_id]))
+        } else {
+            with_no_trimmed_paths!(tables.tcx.def_path_str(tables[def_id]))
+        }
+    }
+
+    fn krate(&self, def_id: stable_mir::DefId) -> Crate {
+        let tables = self.0.borrow();
+        smir_crate(tables.tcx, tables[def_id].krate)
     }
 
     fn span_to_string(&self, span: stable_mir::ty::Span) -> String {
@@ -240,12 +250,29 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         tables.create_def_id(def_id)
     }
 
-    fn instance_mangled_name(&self, def: InstanceDef) -> String {
+    fn instance_mangled_name(&self, instance: InstanceDef) -> Symbol {
         let tables = self.0.borrow_mut();
-        let instance = tables.instances[def];
+        let instance = tables.instances[instance];
         tables.tcx.symbol_name(instance).name.to_string()
     }
 
+    /// Retrieve the instance name for diagnostic messages.
+    ///
+    /// This will return the specialized name, e.g., `Vec<char>::new`.
+    fn instance_name(&self, def: InstanceDef, trimmed: bool) -> Symbol {
+        let tables = self.0.borrow_mut();
+        let instance = tables.instances[def];
+        if trimmed {
+            with_forced_trimmed_paths!(
+                tables.tcx.def_path_str_with_args(instance.def_id(), instance.args)
+            )
+        } else {
+            with_no_trimmed_paths!(
+                tables.tcx.def_path_str_with_args(instance.def_id(), instance.args)
+            )
+        }
+    }
+
     fn mono_instance(&self, item: stable_mir::CrateItem) -> stable_mir::mir::mono::Instance {
         let mut tables = self.0.borrow_mut();
         let def_id = tables[item.0];

compiler/stable_mir/src/crate_def.rs

@@ -0,0 +1,69 @@
+//! Module that define a common trait for things that represent a crate definition,
+//! such as, a function, a trait, an enum, and any other definitions.
+
+use crate::ty::Span;
+use crate::{with, Crate, Symbol};
+
+/// A unique identification number for each item accessible for the current compilation unit.
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+pub struct DefId(pub(crate) usize);
+
+/// A trait for retrieving information about a particular definition.
+///
+/// Implementors must provide the implementation of `def_id` which will be used to retrieve
+/// information about a crate's definition.
+pub trait CrateDef {
+    /// Retrieve the unique identifier for the current definition.
+    fn def_id(&self) -> DefId;
+
+    /// Return the fully qualified name of the current definition.
+    fn name(&self) -> Symbol {
+        let def_id = self.def_id();
+        with(|cx| cx.def_name(def_id, false))
+    }
+
+    /// Return a trimmed name of this definition.
+    ///
+    /// This can be used to print more user friendly diagnostic messages.
+    ///
+    /// If a symbol name can only be imported from one place for a type, and as
+    /// long as it was not glob-imported anywhere in the current crate, we trim its
+    /// path and print only the name.
+    ///
+    /// For example, this function may shorten `std::vec::Vec` to just `Vec`,
+    /// as long as there is no other `Vec` importable anywhere.
+    fn trimmed_name(&self) -> Symbol {
+        let def_id = self.def_id();
+        with(|cx| cx.def_name(def_id, true))
+    }
+
+    /// Return information about the crate where this definition is declared.
+    ///
+    /// This will return the crate number and its name.
+    fn krate(&self) -> Crate {
+        let def_id = self.def_id();
+        with(|cx| cx.krate(def_id))
+    }
+
+    /// Return the span of this definition.
+    fn span(&self) -> Span {
+        let def_id = self.def_id();
+        with(|cx| cx.span_of_an_item(def_id))
+    }
+}
+
+macro_rules! crate_def {
+    ( $(#[$attr:meta])*
+      $vis:vis $name:ident $(;)?
+    ) => {
+        $(#[$attr])*
+        #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+        $vis struct $name(pub DefId);
+
+        impl CrateDef for $name {
+            fn def_id(&self) -> DefId {
+                self.0
+            }
+        }
+    };
+}

compiler/stable_mir/src/lib.rs

@@ -31,12 +31,16 @@ use self::ty::{
 #[macro_use]
 extern crate scoped_tls;
 
+#[macro_use]
+pub mod crate_def;
 #[macro_use]
 pub mod error;
 pub mod mir;
 pub mod ty;
 pub mod visitor;
 
+pub use crate::crate_def::CrateDef;
+pub use crate::crate_def::DefId;
 use crate::mir::alloc::{AllocId, GlobalAlloc};
 use crate::mir::pretty::function_name;
 use crate::mir::Mutability;
@@ -51,15 +55,11 @@ pub type Symbol = String;
 /// The number that identifies a crate.
 pub type CrateNum = usize;
 
-/// A unique identification number for each item accessible for the current compilation unit.
-#[derive(Clone, Copy, PartialEq, Eq, Hash)]
-pub struct DefId(usize);
-
 impl Debug for DefId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("DefId")
             .field("id", &self.0)
-            .field("name", &with(|cx| cx.name_of_def_id(*self)))
+            .field("name", &with(|cx| cx.def_name(*self, false)))
             .finish()
     }
 }
@@ -100,9 +100,10 @@ pub enum ItemKind {
 
 pub type Filename = String;
 
-/// Holds information about an item in the crate.
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub struct CrateItem(pub DefId);
+crate_def! {
+    /// Holds information about an item in a crate.
+    pub CrateItem;
+}
 
 impl CrateItem {
     pub fn body(&self) -> mir::Body {
@@ -113,10 +114,6 @@ impl CrateItem {
         with(|cx| cx.span_of_an_item(self.0))
     }
 
-    pub fn name(&self) -> String {
-        with(|cx| cx.name_of_def_id(self.0))
-    }
-
     pub fn kind(&self) -> ItemKind {
         with(|cx| cx.item_kind(*self))
     }
@@ -205,7 +202,7 @@ pub trait Context {
     fn find_crates(&self, name: &str) -> Vec<Crate>;
 
     /// Returns the name of given `DefId`
-    fn name_of_def_id(&self, def_id: DefId) -> String;
+    fn def_name(&self, def_id: DefId, trimmed: bool) -> Symbol;
 
     /// Returns printable, human readable form of `Span`
     fn span_to_string(&self, span: Span) -> String;
@@ -260,7 +257,7 @@ pub trait Context {
     fn instance_def_id(&self, instance: InstanceDef) -> DefId;
 
     /// Get the instance mangled name.
-    fn instance_mangled_name(&self, instance: InstanceDef) -> String;
+    fn instance_mangled_name(&self, instance: InstanceDef) -> Symbol;
 
     /// Convert a non-generic crate item into an instance.
     /// This function will panic if the item is generic.
@@ -294,6 +291,8 @@ pub trait Context {
 
     /// Retrieve the id for the virtual table.
     fn vtable_allocation(&self, global_alloc: &GlobalAlloc) -> Option<AllocId>;
+    fn krate(&self, def_id: DefId) -> Crate;
+    fn instance_name(&self, def: InstanceDef, trimmed: bool) -> Symbol;
 }
 
 // A thread local variable that stores a pointer to the tables mapping between TyCtxt

compiler/stable_mir/src/mir/mono.rs

@@ -1,6 +1,7 @@
+use crate::crate_def::CrateDef;
 use crate::mir::Body;
 use crate::ty::{Allocation, ClosureDef, ClosureKind, FnDef, GenericArgs, IndexedVal, Ty};
-use crate::{with, CrateItem, DefId, Error, ItemKind, Opaque};
+use crate::{with, CrateItem, DefId, Error, ItemKind, Opaque, Symbol};
 use std::fmt::{Debug, Formatter};
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
@@ -47,10 +48,29 @@ impl Instance {
         with(|context| context.instance_ty(self.def))
     }
 
-    pub fn mangled_name(&self) -> String {
+    /// Retrieve the instance's mangled name used for calling the given instance.
+    ///
+    /// This will also look up the correct name of instances from upstream crates.
+    pub fn mangled_name(&self) -> Symbol {
         with(|context| context.instance_mangled_name(self.def))
     }
 
+    /// Retrieve the instance name for diagnostic messages.
+    ///
+    /// This will return the specialized name, e.g., `std::vec::Vec<u8>::new`.
+    pub fn name(&self) -> Symbol {
+        with(|context| context.instance_name(self.def, false))
+    }
+
+    /// Return a trimmed name of the given instance including its args.
+    ///
+    /// If a symbol name can only be imported from one place for a type, and as
+    /// long as it was not glob-imported anywhere in the current crate, we trim its
+    /// path and print only the name.
+    pub fn trimmed_name(&self) -> Symbol {
+        with(|context| context.instance_name(self.def, true))
+    }
+
     /// Resolve an instance starting from a function definition and generic arguments.
     pub fn resolve(def: FnDef, args: &GenericArgs) -> Result<Instance, crate::Error> {
         with(|context| {
@@ -104,6 +124,8 @@ impl TryFrom<CrateItem> for Instance {
 
     fn try_from(item: CrateItem) -> Result<Self, Self::Error> {
         with(|context| {
+            // FIXME(celinval):
+            // - Return `Err` if instance does not have a body.
             if !context.requires_monomorphization(item.0) {
                 Ok(context.mono_instance(item))
             } else {
@@ -148,8 +170,10 @@ impl From<StaticDef> for CrateItem {
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct InstanceDef(usize);
 
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
-pub struct StaticDef(pub DefId);
+crate_def! {
+    /// Holds information about a static variable definition.
+    pub StaticDef;
+}
 
 impl TryFrom<CrateItem> for StaticDef {
     type Error = crate::Error;

compiler/stable_mir/src/mir/pretty.rs

@@ -1,3 +1,4 @@
+use crate::crate_def::CrateDef;
 use crate::mir::{Operand, Rvalue, StatementKind};
 use crate::ty::{DynKind, FloatTy, IntTy, RigidTy, TyKind, UintTy};
 use crate::{with, Body, CrateItem, Mutability};