Add the ability for SCC passes to initialize and finalize themselves

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13084 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CallGraphSCCPass.h

@@ -26,9 +26,16 @@
 namespace llvm {
 
 class CallGraphNode;
+class Module;
 
 struct CallGraphSCCPass : public Pass {
 
+  /// doInitialization - This method is called before the SCC's of the program
+  /// has been processed, allowing the pass to do initialization as necessary.
+  virtual bool doInitialization(Module &M) {
+    return false;
+  }
+
   /// runOnSCC - This method should be implemented by the subclass to perform
   /// whatever action is necessary for the specified SCC.  Note that
   /// non-recursive (or only self-recursive) functions will have an SCC size of
@@ -36,6 +43,12 @@ struct CallGraphSCCPass : public Pass {
   ///
   virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC) = 0;
 
+  /// doFinalization - This method is called after the SCC's of the program has
+  /// been processed, allowing the pass to do final cleanup as necessary.
+  virtual bool doFinalization(Module &M) {
+    return false;
+  }
+
   /// run - Run this pass, returning true if a modification was made to the
   /// module argument.  This is implemented in terms of the runOnSCC method.
   ///