Support for reading run counts in llvm-cov.

[oota-llvm.git] / include / llvm / Support / BlockFrequency.h

diff --git a/include/llvm/Support/BlockFrequency.h b/include/llvm/Support/BlockFrequency.h
index b133c961f632b3b5153156cffde8dc4903758bef..666b3c822dbcd215fe77193b8e56a280c53f2c65 100644 (file)
--- a/include/llvm/Support/BlockFrequency.h
+++ b/include/llvm/Support/BlockFrequency.h
@@ -14,6 +14,8 @@
 #ifndef LLVM_SUPPORT_BLOCKFREQUENCY_H
 #define LLVM_SUPPORT_BLOCKFREQUENCY_H
 
+#include "llvm/Support/DataTypes.h"
+
 namespace llvm {
 
 class raw_ostream;
@@ -23,18 +25,35 @@ class BranchProbability;
 class BlockFrequency {
 
   uint64_t Frequency;
+  static const int64_t ENTRY_FREQ = 1 << 14;
 
-  static void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]);
-  static uint64_t div96bit(uint64_t W[2], uint32_t D);
+  // Scale frequency by N/D, saturating on overflow.
+  void scale(uint32_t N, uint32_t D);
 
 public:
   BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
 
+  /// \brief Returns the frequency of the entry block of the function.
+  static uint64_t getEntryFrequency() { return ENTRY_FREQ; }
+
+  /// \brief Returns the maximum possible frequency, the saturation value.
+  static uint64_t getMaxFrequency() { return -1ULL; }
+
+  /// \brief Returns the frequency as a fixpoint number scaled by the entry
+  /// frequency.
   uint64_t getFrequency() const { return Frequency; }
 
+  /// \brief Multiplies with a branch probability. The computation will never
+  /// overflow.
   BlockFrequency &operator*=(const BranchProbability &Prob);
   const BlockFrequency operator*(const BranchProbability &Prob) const;
 
+  /// \brief Divide by a non-zero branch probability using saturating
+  /// arithmetic.
+  BlockFrequency &operator/=(const BranchProbability &Prob);
+  BlockFrequency operator/(const BranchProbability &Prob) const;
+
+  /// \brief Adds another block frequency using saturating arithmetic.
   BlockFrequency &operator+=(const BlockFrequency &Freq);
   const BlockFrequency operator+(const BlockFrequency &Freq) const;