lib/Analysis/ProfileInfo.cpp

   1 //===- ProfileInfo.cpp - Profile Info Interface ---------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the abstract ProfileInfo interface, and the default
  11 // "no profile" implementation.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Analysis/Passes.h"
  16 #include "llvm/Analysis/ProfileInfo.h"
  17 #include "llvm/Pass.h"
  18 #include "llvm/Support/CFG.h"
  19 #include "llvm/Support/Compiler.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include <set>
  22 using namespace llvm;
  23
  24 // Register the ProfileInfo interface, providing a nice name to refer to.
  25 static RegisterAnalysisGroup<ProfileInfo> Z("Profile Information");
  26 char ProfileInfo::ID = 0;
  27
  28 ProfileInfo::~ProfileInfo() {}
  29
  30 const double ProfileInfo::MissingValue = -1;
  31
  32 double ProfileInfo::getExecutionCount(const BasicBlock *BB) {
  33   std::map<const Function*, BlockCounts>::iterator J =
  34     BlockInformation.find(BB->getParent());
  35   if (J != BlockInformation.end()) {
  36     BlockCounts::iterator I = J->second.find(BB);
  37     if (I != J->second.end())
  38       return I->second;
  39   }
  40
  41   pred_const_iterator PI = pred_begin(BB), PE = pred_end(BB);
  42
  43   // Are there zero predecessors of this block?
  44   if (PI == PE) {
  45     // If this is the entry block, look for the Null -> Entry edge.
  46     if (BB == &BB->getParent()->getEntryBlock())
  47       return getEdgeWeight(getEdge(0, BB));
  48     else
  49       return 0;   // Otherwise, this is a dead block.
  50   }
  51
  52   // Otherwise, if there are predecessors, the execution count of this block is
  53   // the sum of the edge frequencies from the incoming edges.
  54   std::set<const BasicBlock*> ProcessedPreds;
  55   double Count = 0;
  56   for (; PI != PE; ++PI)
  57     if (ProcessedPreds.insert(*PI).second) {
  58       double w = getEdgeWeight(getEdge(*PI, BB));
  59       if (w == MissingValue) {
  60         Count = MissingValue;
  61         break;
  62       }
  63       Count += w;
  64     }
  65
  66   if (Count != MissingValue) BlockInformation[BB->getParent()][BB] = Count;
  67   return Count;
  68 }
  69
  70 double ProfileInfo::getExecutionCount(const Function *F) {
  71   std::map<const Function*, double>::iterator J =
  72     FunctionInformation.find(F);
  73   if (J != FunctionInformation.end())
  74     return J->second;
  75
  76   // isDeclaration() is checked here and not at start of function to allow
  77   // functions without a body still to have a execution count.
  78   if (F->isDeclaration()) return MissingValue;
  79
  80   double Count = getExecutionCount(&F->getEntryBlock());
  81   if (Count != MissingValue) FunctionInformation[F] = Count;
  82   return Count;
  83 }
  84
  85 raw_ostream& llvm::operator<<(raw_ostream &O, ProfileInfo::Edge E) {
  86   O << "(";
  87   O << (E.first ? E.first->getNameStr() : "0");
  88   O << ",";
  89   O << (E.second ? E.second->getNameStr() : "0");
  90   return O << ")";
  91 }
  92
  93 //===----------------------------------------------------------------------===//
  94 //  NoProfile ProfileInfo implementation
  95 //
  96
  97 namespace {
  98   struct VISIBILITY_HIDDEN NoProfileInfo
  99     : public ImmutablePass, public ProfileInfo {
 100     static char ID; // Class identification, replacement for typeinfo
 101     NoProfileInfo() : ImmutablePass(&ID) {}
 102   };
 103 }  // End of anonymous namespace
 104
 105 char NoProfileInfo::ID = 0;
 106 // Register this pass...
 107 static RegisterPass<NoProfileInfo>
 108 X("no-profile", "No Profile Information", false, true);
 109
 110 // Declare that we implement the ProfileInfo interface
 111 static RegisterAnalysisGroup<ProfileInfo, true> Y(X);
 112
 113 ImmutablePass *llvm::createNoProfileInfoPass() { return new NoProfileInfo(); }