2 files changed, 14 insertions, 0 deletions
diff --git a/src/librustc_data_structures/graph/mod.rs b/src/librustc_data_structures/graph/mod.rs
index a5f83ce05f5..474622f3669 100644
--- a/src/librustc_data_structures/graph/mod.rs
+++ b/src/librustc_data_structures/graph/mod.rs
@@ -114,6 +114,13 @@ impl<N: Debug, E: Debug> Graph<N, E> {
         }
     }
 
+    pub fn with_capacity(nodes: usize, edges: usize) -> Graph<N, E> {
+        Graph {
+            nodes: SnapshotVec::with_capacity(nodes),
+            edges: SnapshotVec::with_capacity(edges),
+        }
+    }
+
     // # Simple accessors
 
     #[inline]
diff --git a/src/librustc_data_structures/snapshot_vec.rs b/src/librustc_data_structures/snapshot_vec.rs
index dac074ab91e..2da91918288 100644
--- a/src/librustc_data_structures/snapshot_vec.rs
+++ b/src/librustc_data_structures/snapshot_vec.rs
@@ -66,6 +66,13 @@ impl<D: SnapshotVecDelegate> SnapshotVec<D> {
         }
     }
 
+    pub fn with_capacity(n: usize) -> SnapshotVec<D> {
+        SnapshotVec {
+            values: Vec::with_capacity(n),
+            undo_log: Vec::new(),
+        }
+    }
+
     fn in_snapshot(&self) -> bool {
         !self.undo_log.is_empty()
     }