Teach the BranchProbabilityInfo pass to print its results, and use that

to bring it under direct test instead of merely indirectly testing it in
the BlockFrequencyInfo pass.

The next step is to start adding tests for the various heuristics
employed, and to start fixing those heuristics once they're under test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142778 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/BranchProbabilityInfo.h

@@ -37,6 +37,9 @@ class BranchProbabilityInfo : public FunctionPass {
 
   DenseMap<Edge, uint32_t> Weights;
 
+  /// \brief Track the last function we run over for printing.
+  Function *LastF;
+
   // Get sum of the block successors' weights.
   uint32_t getSumForBlock(const BasicBlock *BB) const;
 
@@ -48,8 +51,8 @@ public:
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const;
-
   bool runOnFunction(Function &F);
+  void print(raw_ostream &OS, const Module *M = 0) const;
 
   // Returned value is between 1 and UINT32_MAX. Look at
   // BranchProbabilityInfo.cpp for details.
@@ -74,8 +77,8 @@ public:
   // 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;
+  raw_ostream &printEdgeProbability(raw_ostream &OS, const BasicBlock *Src,
+                                    const BasicBlock *Dst) const;
 };
 
 }