diff --git a/include/llvm/CodeGen/MachineJumpTableInfo.h b/include/llvm/CodeGen/MachineJumpTableInfo.h
index 6f667078875..2d640a7cb10 100644
--- a/include/llvm/CodeGen/MachineJumpTableInfo.h
+++ b/include/llvm/CodeGen/MachineJumpTableInfo.h
@@ -34,7 +34,7 @@ struct MachineJumpTableEntry {
   /// MBBs - The vector of basic blocks from which to create the jump table.
   std::vector<MachineBasicBlock*> MBBs;
   
-  MachineJumpTableEntry(std::vector<MachineBasicBlock*> &M) : MBBs(M) {}
+  MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M) : MBBs(M) {}
 };
   
 class MachineJumpTableInfo {
@@ -45,7 +45,7 @@ public:
     
   /// getJumpTableIndex - Create a new jump table or return an existing one.
   ///
-  unsigned getJumpTableIndex(std::vector<MachineBasicBlock*> &DestBBs);
+  unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs);
   
   /// isEmpty - Return true if there are no jump tables.
   ///
diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index 7617de962d7..5d82f722ef5 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -362,7 +362,7 @@ void MachineFrameInfo::dump(const MachineFunction &MF) const {
 /// or return an existing one.
 ///
 unsigned MachineJumpTableInfo::getJumpTableIndex(
-                                     std::vector<MachineBasicBlock*> &DestBBs) {
+                               const std::vector<MachineBasicBlock*> &DestBBs) {
   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
     if (JumpTables[i].MBBs == DestBBs)