Auto merge of #142388 - cjgillot:span-hash, r=davidtwco

Do not clone Arc when hashing span.

Tiny improvement I was when trying to profile span hashing.

Author: bors

compiler/rustc_query_system/src/ich/hcx.rs

@@ -1,13 +1,13 @@
-use std::sync::Arc;
-
 use rustc_ast as ast;
 use rustc_data_structures::stable_hasher::{HashStable, HashingControls, StableHasher};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::definitions::DefPathHash;
 use rustc_session::Session;
 use rustc_session::cstore::Untracked;
 use rustc_span::source_map::SourceMap;
-use rustc_span::{BytePos, CachingSourceMapView, DUMMY_SP, SourceFile, Span, SpanData, Symbol};
+use rustc_span::{
+    BytePos, CachingSourceMapView, DUMMY_SP, Span, SpanData, StableSourceFileId, Symbol,
+};
 
 use crate::ich;
 
@@ -118,7 +118,7 @@ impl<'a> rustc_span::HashStableContext for StableHashingContext<'a> {
     fn span_data_to_lines_and_cols(
         &mut self,
         span: &SpanData,
-    ) -> Option<(Arc<SourceFile>, usize, BytePos, usize, BytePos)> {
+    ) -> Option<(StableSourceFileId, usize, BytePos, usize, BytePos)> {
         self.source_map().span_data_to_lines_and_cols(span)
     }
 

compiler/rustc_span/src/caching_source_map_view.rs

@@ -2,7 +2,7 @@ use std::ops::Range;
 use std::sync::Arc;
 
 use crate::source_map::SourceMap;
-use crate::{BytePos, Pos, RelativeBytePos, SourceFile, SpanData};
+use crate::{BytePos, Pos, RelativeBytePos, SourceFile, SpanData, StableSourceFileId};
 
 #[derive(Clone)]
 struct CacheEntry {
@@ -114,7 +114,7 @@ impl<'sm> CachingSourceMapView<'sm> {
     pub fn span_data_to_lines_and_cols(
         &mut self,
         span_data: &SpanData,
-    ) -> Option<(Arc<SourceFile>, usize, BytePos, usize, BytePos)> {
+    ) -> Option<(StableSourceFileId, usize, BytePos, usize, BytePos)> {
         self.time_stamp += 1;
 
         // Check if lo and hi are in the cached lines.
@@ -132,7 +132,7 @@ impl<'sm> CachingSourceMapView<'sm> {
                 }
 
                 (
-                    Arc::clone(&lo.file),
+                    lo.file.stable_id,
                     lo.line_number,
                     span_data.lo - lo.line.start,
                     hi.line_number,
@@ -226,7 +226,7 @@ impl<'sm> CachingSourceMapView<'sm> {
         assert_eq!(lo.file_index, hi.file_index);
 
         Some((
-            Arc::clone(&lo.file),
+            lo.file.stable_id,
             lo.line_number,
             span_data.lo - lo.line.start,
             hi.line_number,

compiler/rustc_span/src/lib.rs

@@ -2600,7 +2600,7 @@ pub trait HashStableContext {
     fn span_data_to_lines_and_cols(
         &mut self,
         span: &SpanData,
-    ) -> Option<(Arc<SourceFile>, usize, BytePos, usize, BytePos)>;
+    ) -> Option<(StableSourceFileId, usize, BytePos, usize, BytePos)>;
     fn hashing_controls(&self) -> HashingControls;
 }
 
@@ -2657,7 +2657,7 @@ where
         };
 
         Hash::hash(&TAG_VALID_SPAN, hasher);
-        Hash::hash(&file.stable_id, hasher);
+        Hash::hash(&file, hasher);
 
         // Hash both the length and the end location (line/column) of a span. If we
         // hash only the length, for example, then two otherwise equal spans with