ICH: Make CachingCodemapView robustly handle invalid spans.

src/librustc_incremental/calculate_svh/caching_codemap_view.rs

@@ -53,16 +53,16 @@ impl<'tcx> CachingCodemapView<'tcx> {
 
     pub fn byte_pos_to_line_and_col(&mut self,
                                     pos: BytePos)
-                                    -> (Rc<FileMap>, usize, BytePos) {
+                                    -> Option<(Rc<FileMap>, usize, BytePos)> {
         self.time_stamp += 1;
 
         // Check if the position is in one of the cached lines
         for cache_entry in self.line_cache.iter_mut() {
             if pos >= cache_entry.line_start && pos < cache_entry.line_end {
                 cache_entry.time_stamp = self.time_stamp;
-                return (cache_entry.file.clone(),
-                        cache_entry.line_number,
-                        pos - cache_entry.line_start);
+                return Some((cache_entry.file.clone(),
+                             cache_entry.line_number,
+                             pos - cache_entry.line_start));
             }
         }
 
@@ -78,8 +78,26 @@ impl<'tcx> CachingCodemapView<'tcx> {
 
         // If the entry doesn't point to the correct file, fix it up
         if pos < cache_entry.file.start_pos || pos >= cache_entry.file.end_pos {
-            let file_index = self.codemap.lookup_filemap_idx(pos);
-            cache_entry.file = self.codemap.files.borrow()[file_index].clone();
+            let file_valid;
+            let files = self.codemap.files.borrow();
+
+            if files.len() > 0 {
+                let file_index = self.codemap.lookup_filemap_idx(pos);
+                let file = files[file_index].clone();
+
+                if pos >= file.start_pos && pos < file.end_pos {
+                    cache_entry.file = file;
+                    file_valid = true;
+                } else {
+                    file_valid = false;
+                }
+            } else {
+                file_valid = false;
+            }
+
+            if !file_valid {
+                return None;
+            }
         }
 
         let line_index = cache_entry.file.lookup_line(pos).unwrap();
@@ -90,8 +108,8 @@ impl<'tcx> CachingCodemapView<'tcx> {
         cache_entry.line_end = line_bounds.1;
         cache_entry.time_stamp = self.time_stamp;
 
-        return (cache_entry.file.clone(),
-                cache_entry.line_number,
-                pos - cache_entry.line_start);
+        return Some((cache_entry.file.clone(),
+                     cache_entry.line_number,
+                     pos - cache_entry.line_start));
     }
 }

src/librustc_incremental/calculate_svh/svh_visitor.rs

@@ -86,8 +86,8 @@ impl<'a, 'hash, 'tcx> StrictVersionHashVisitor<'a, 'hash, 'tcx> {
             span.hi
         };
 
-        let (file1, line1, col1) = self.codemap.byte_pos_to_line_and_col(span.lo);
-        let (file2, line2, col2) = self.codemap.byte_pos_to_line_and_col(span_hi);
+        let loc1 = self.codemap.byte_pos_to_line_and_col(span.lo);
+        let loc2 = self.codemap.byte_pos_to_line_and_col(span_hi);
 
         let expansion_kind = match span.expn_id {
             NO_EXPANSION => SawSpanExpnKind::NoExpansion,
@@ -95,9 +95,10 @@ impl<'a, 'hash, 'tcx> StrictVersionHashVisitor<'a, 'hash, 'tcx> {
             _ => SawSpanExpnKind::SomeExpansion,
         };
 
-        SawSpan(&file1.name[..], line1, col1,
-                &file2.name[..], line2, col2,
-                expansion_kind).hash(self.st);
+        SawSpan(loc1.as_ref().map(|&(ref fm, line, col)| (&fm.name[..], line, col)),
+                loc2.as_ref().map(|&(ref fm, line, col)| (&fm.name[..], line, col)),
+                expansion_kind)
+            .hash(self.st);
 
         if expansion_kind == SawSpanExpnKind::SomeExpansion {
             let call_site = self.codemap.codemap().source_callsite(span);
@@ -171,7 +172,9 @@ enum SawAbiComponent<'a> {
     SawAssocTypeBinding,
     SawAttribute(ast::AttrStyle),
     SawMacroDef,
-    SawSpan(&'a str, usize, BytePos, &'a str, usize, BytePos, SawSpanExpnKind),
+    SawSpan(Option<(&'a str, usize, BytePos)>,
+            Option<(&'a str, usize, BytePos)>,
+            SawSpanExpnKind),
 }
 
 /// SawExprComponent carries all of the information that we want