1 files changed, 78 insertions, 0 deletions
diff --git a/include/llvm/Analysis/BranchProbabilityInfo.h b/include/llvm/Analysis/BranchProbabilityInfo.h
new file mode 100644
index 0000000..91f289d
--- /dev/null
+++ b/include/llvm/Analysis/BranchProbabilityInfo.h
@@ -0,0 +1,78 @@
+//===--- BranchProbabilityInfo.h - Branch Probability Analysis --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass is used to evaluate branch probabilties.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_BRANCHPROBABILITYINFO_H
+#define LLVM_ANALYSIS_BRANCHPROBABILITYINFO_H
+
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/BranchProbability.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+namespace llvm {
+
+class raw_ostream;
+
+class BranchProbabilityInfo : public FunctionPass {
+
+  // Default weight value. Used when we don't have information about the edge.
+  static const uint32_t DEFAULT_WEIGHT = 16;
+
+  typedef std::pair<BasicBlock *, BasicBlock *> Edge;
+
+  DenseMap<Edge, uint32_t> Weights;
+
+  // Get sum of the block successors' weights.
+  uint32_t getSumForBlock(BasicBlock *BB) const;
+
+public:
+  static char ID;
+
+  BranchProbabilityInfo() : FunctionPass(ID) {
+    initializeBranchProbabilityInfoPass(*PassRegistry::getPassRegistry());
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.addRequired<LoopInfo>();
+    AU.setPreservesAll();
+  }
+
+  bool runOnFunction(Function &F);
+
+  // Returned value is between 1 and UINT32_MAX. Look at
+  // BranchProbabilityInfo.cpp for details.
+  uint32_t getEdgeWeight(BasicBlock *Src, BasicBlock *Dst) const;
+
+  // Look at BranchProbabilityInfo.cpp for details. Use it with caution!
+  void setEdgeWeight(BasicBlock *Src, BasicBlock *Dst, uint32_t Weight);
+
+  // A 'Hot' edge is an edge which probability is >= 80%.
+  bool isEdgeHot(BasicBlock *Src, BasicBlock *Dst) const;
+
+  // Return a hot successor for the block BB or null if there isn't one.
+  BasicBlock *getHotSucc(BasicBlock *BB) const;
+
+  // Return a probability as a fraction between 0 (0% probability) and
+  // 1 (100% probability), however the value is never equal to 0, and can be 1
+  // only iff SRC block has only one successor.
+  BranchProbability getEdgeProbability(BasicBlock *Src, BasicBlock *Dst) const;
+
+  // Print value between 0 (0% probability) and 1 (100% probability),
+  // however the value is never equal to 0, and can be 1 only iff SRC block
+  // has only one successor.
+  raw_ostream &printEdgeProbability(raw_ostream &OS, BasicBlock *Src,
+                                    BasicBlock *Dst) const;
+};
+
+}
+
+#endif