1 files changed, 38 insertions, 0 deletions
diff --git a/lib/Analysis/IPA/CallGraphSCCPass.cpp b/lib/Analysis/IPA/CallGraphSCCPass.cpp
new file mode 100644
index 0000000000..360bc23be3
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+++ b/lib/Analysis/IPA/CallGraphSCCPass.cpp
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+//===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the CallGraphSCCPass class, which is used for passes
+// which are implemented as bottom-up traversals on the call graph.  Because
+// there may be cycles in the call graph, passes of this type operate on the
+// call-graph in SCC order: that is, they process function bottom-up, except for
+// recursive functions, which they process all at once.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CallGraphSCCPass.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/ADT/SCCIterator.h"
+using namespace llvm;
+
+/// getAnalysisUsage - For this class, we declare that we require and preserve
+/// the call graph.  If the derived class implements this method, it should
+/// always explicitly call the implementation here.
+void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<CallGraph>();
+  AU.addPreserved<CallGraph>();
+}
+
+bool CallGraphSCCPass::runOnModule(Module &M) {
+  CallGraph &CG = getAnalysis<CallGraph>();
+  bool Changed = doInitialization(CG);
+  for (scc_iterator<CallGraph*> I = scc_begin(&CG), E = scc_end(&CG);
+       I != E; ++I)
+    Changed = runOnSCC(*I);
+  return Changed | doFinalization(CG);
+}