Rollup merge of #116630 - ouz-a:smir_span_better, r=oli-obk

Add ability to get lines/filename for Span in smir

Wasn't sure about how to structure lines, so went with safest option, also I'm not sure why `span_to_lines` returns `vec`.

Addresses rust-lang/project-stable-mir#44

r? ``@oli-obk``

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -17,8 +17,10 @@ use rustc_middle::ty::{self, Ty, TyCtxt, Variance};
 use rustc_span::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_target::abi::FieldIdx;
 use stable_mir::mir::{CopyNonOverlapping, Statement, UserTypeProjection, VariantIdx};
-use stable_mir::ty::{FloatTy, GenericParamDef, IntTy, Movability, RigidTy, Span, TyKind, UintTy};
-use stable_mir::{self, opaque, Context};
+use stable_mir::ty::{
+    FloatTy, GenericParamDef, IntTy, LineInfo, Movability, RigidTy, Span, TyKind, UintTy,
+};
+use stable_mir::{self, opaque, Context, Filename};
 use tracing::debug;
 
 mod alloc;
@@ -50,10 +52,27 @@ impl<'tcx> Context for Tables<'tcx> {
         self.tcx.def_path_str(self[def_id])
     }
 
-    fn print_span(&self, span: stable_mir::ty::Span) -> String {
+    fn span_to_string(&self, span: stable_mir::ty::Span) -> String {
         self.tcx.sess.source_map().span_to_diagnostic_string(self[span])
     }
 
+    fn get_filename(&self, span: &Span) -> Filename {
+        opaque(
+            &self
+                .tcx
+                .sess
+                .source_map()
+                .span_to_filename(self[*span])
+                .display(rustc_span::FileNameDisplayPreference::Local)
+                .to_string(),
+        )
+    }
+
+    fn get_lines(&self, span: &Span) -> LineInfo {
+        let lines = &self.tcx.sess.source_map().span_to_location_info(self[*span]);
+        LineInfo { start_line: lines.1, start_col: lines.2, end_line: lines.3, end_col: lines.4 }
+    }
+
     fn def_kind(&mut self, def_id: stable_mir::DefId) -> stable_mir::DefKind {
         self.tcx.def_kind(self[def_id]).stable(self)
     }

compiler/stable_mir/src/lib.rs

@@ -22,8 +22,8 @@ use std::fmt;
 use std::fmt::Debug;
 
 use self::ty::{
-    GenericPredicates, Generics, ImplDef, ImplTrait, IndexedVal, Span, TraitDecl, TraitDef, Ty,
-    TyKind,
+    GenericPredicates, Generics, ImplDef, ImplTrait, IndexedVal, LineInfo, Span, TraitDecl,
+    TraitDef, Ty, TyKind,
 };
 
 #[macro_use]
@@ -108,6 +108,7 @@ pub struct Crate {
 }
 
 pub type DefKind = Opaque;
+pub type Filename = Opaque;
 
 /// Holds information about an item in the crate.
 /// For now, it only stores the item DefId. Use functions inside `rustc_internal` module to
@@ -196,13 +197,19 @@ pub trait Context {
     /// Find a crate with the given name.
     fn find_crates(&self, name: &str) -> Vec<Crate>;
 
-    /// Prints the name of given `DefId`
+    /// Returns 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;
+    /// Returns printable, human readable form of `Span`
+    fn span_to_string(&self, span: Span) -> String;
 
-    /// Prints the kind of given `DefId`
+    /// Return filename from given `Span`, for diagnostic purposes
+    fn get_filename(&self, span: &Span) -> Filename;
+
+    /// Return lines corresponding to this `Span`
+    fn get_lines(&self, span: &Span) -> LineInfo;
+
+    /// Returns the `kind` of given `DefId`
     fn def_kind(&mut self, def_id: DefId) -> DefKind;
 
     /// `Span` of an item

compiler/stable_mir/src/ty.rs

@@ -3,7 +3,7 @@ use super::{
     mir::{Body, Mutability},
     with, AllocId, DefId, Symbol,
 };
-use crate::Opaque;
+use crate::{Filename, Opaque};
 use std::fmt::{self, Debug, Formatter};
 
 #[derive(Copy, Clone)]
@@ -81,11 +81,33 @@ impl Debug for Span {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         f.debug_struct("Span")
             .field("id", &self.0)
-            .field("repr", &with(|cx| cx.print_span(*self)))
+            .field("repr", &with(|cx| cx.span_to_string(*self)))
             .finish()
     }
 }
 
+impl Span {
+    /// Return filename for diagnostic purposes
+    pub fn get_filename(&self) -> Filename {
+        with(|c| c.get_filename(self))
+    }
+
+    /// Return lines that corespond to this `Span`
+    pub fn get_lines(&self) -> LineInfo {
+        with(|c| c.get_lines(&self))
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+/// Information you get from `Span` in a struct form.
+/// Line and col start from 1.
+pub struct LineInfo {
+    pub start_line: usize,
+    pub start_col: usize,
+    pub end_line: usize,
+    pub end_col: usize,
+}
+
 impl IndexedVal for Span {
     fn to_val(index: usize) -> Self {
         Span(index)