Add function to replace a destination MBB in a single jump table

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88804 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index e125638..3df88fc 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -545,14 +545,25 @@
                                              MachineBasicBlock *New) {
   assert(Old != New && "Not making a change?");
   bool MadeChange = false;
-  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
-    MachineJumpTableEntry &JTE = JumpTables[i];
-    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
-      if (JTE.MBBs[j] == Old) {
-        JTE.MBBs[j] = New;
-        MadeChange = true;
-      }
-  }
+  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
+    ReplaceMBBInJumpTable(i, Old, New);
+  return MadeChange;
+}
+
+/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
+/// the jump table to branch to New instead.
+bool
+MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
+                                            MachineBasicBlock *Old,
+                                            MachineBasicBlock *New) {
+  assert(Old != New && "Not making a change?");
+  bool MadeChange = false;
+  MachineJumpTableEntry &JTE = JumpTables[Idx];
+  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
+    if (JTE.MBBs[j] == Old) {
+      JTE.MBBs[j] = New;
+      MadeChange = true;
+    }
   return MadeChange;
 }