lib/Analysis/ProfileInfoLoader.cpp

   1 //===- ProfileInfoLoad.cpp - Load profile information from disk -----------===//
   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 // The ProfileInfoLoader class is used to load and represent profiling
  11 // information read in from the dump file.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Analysis/ProfileInfoLoader.h"
  16 #include "llvm/Analysis/ProfileInfoTypes.h"
  17 #include "llvm/Module.h"
  18 #include "llvm/InstrTypes.h"
  19 #include "llvm/Support/Streams.h"
  20 #include <cstdio>
  21 #include <cstdlib>
  22 #include <map>
  23 using namespace llvm;
  24
  25 // ByteSwap - Byteswap 'Var' if 'Really' is true.
  26 //
  27 static inline unsigned ByteSwap(unsigned Var, bool Really) {
  28   if (!Really) return Var;
  29   return ((Var & (255<< 0)) << 24) |
  30          ((Var & (255<< 8)) <<  8) |
  31          ((Var & (255<<16)) >>  8) |
  32          ((Var & (255<<24)) >> 24);
  33 }
  34
  35 static void ReadProfilingBlock(const char *ToolName, FILE *F,
  36                                bool ShouldByteSwap,
  37                                std::vector<unsigned> &Data) {
  38   // Read the number of entries...
  39   unsigned NumEntries;
  40   if (fread(&NumEntries, sizeof(unsigned), 1, F) != 1) {
  41     cerr << ToolName << ": data packet truncated!\n";
  42     perror(0);
  43     exit(1);
  44   }
  45   NumEntries = ByteSwap(NumEntries, ShouldByteSwap);
  46
  47   // Read the counts...
  48   std::vector<unsigned> TempSpace(NumEntries);
  49
  50   // Read in the block of data...
  51   if (fread(&TempSpace[0], sizeof(unsigned)*NumEntries, 1, F) != 1) {
  52     cerr << ToolName << ": data packet truncated!\n";
  53     perror(0);
  54     exit(1);
  55   }
  56
  57   // Make sure we have enough space...
  58   if (Data.size() < NumEntries)
  59     Data.resize(NumEntries);
  60
  61   // Accumulate the data we just read into the data.
  62   if (!ShouldByteSwap) {
  63     for (unsigned i = 0; i != NumEntries; ++i)
  64       Data[i] += TempSpace[i];
  65   } else {
  66     for (unsigned i = 0; i != NumEntries; ++i)
  67       Data[i] += ByteSwap(TempSpace[i], true);
  68   }
  69 }
  70
  71 // ProfileInfoLoader ctor - Read the specified profiling data file, exiting the
  72 // program if the file is invalid or broken.
  73 //
  74 ProfileInfoLoader::ProfileInfoLoader(const char *ToolName,
  75                                      const std::string &Filename,
  76                                      Module &TheModule) : M(TheModule) {
  77   FILE *F = fopen(Filename.c_str(), "r");
  78   if (F == 0) {
  79     cerr << ToolName << ": Error opening '" << Filename << "': ";
  80     perror(0);
  81     exit(1);
  82   }
  83
  84   // Keep reading packets until we run out of them.
  85   unsigned PacketType;
  86   while (fread(&PacketType, sizeof(unsigned), 1, F) == 1) {
  87     // If the low eight bits of the packet are zero, we must be dealing with an
  88     // endianness mismatch.  Byteswap all words read from the profiling
  89     // information.
  90     bool ShouldByteSwap = (char)PacketType == 0;
  91     PacketType = ByteSwap(PacketType, ShouldByteSwap);
  92
  93     switch (PacketType) {
  94     case ArgumentInfo: {
  95       unsigned ArgLength;
  96       if (fread(&ArgLength, sizeof(unsigned), 1, F) != 1) {
  97         cerr << ToolName << ": arguments packet truncated!\n";
  98         perror(0);
  99         exit(1);
 100       }
 101       ArgLength = ByteSwap(ArgLength, ShouldByteSwap);
 102
 103       // Read in the arguments...
 104       std::vector<char> Chars(ArgLength+4);
 105
 106       if (ArgLength)
 107         if (fread(&Chars[0], (ArgLength+3) & ~3, 1, F) != 1) {
 108           cerr << ToolName << ": arguments packet truncated!\n";
 109           perror(0);
 110           exit(1);
 111         }
 112       CommandLines.push_back(std::string(&Chars[0], &Chars[ArgLength]));
 113       break;
 114     }
 115
 116     case FunctionInfo:
 117       ReadProfilingBlock(ToolName, F, ShouldByteSwap, FunctionCounts);
 118       break;
 119
 120     case BlockInfo:
 121       ReadProfilingBlock(ToolName, F, ShouldByteSwap, BlockCounts);
 122       break;
 123
 124     case EdgeInfo:
 125       ReadProfilingBlock(ToolName, F, ShouldByteSwap, EdgeCounts);
 126       break;
 127
 128     case BBTraceInfo:
 129       ReadProfilingBlock(ToolName, F, ShouldByteSwap, BBTrace);
 130       break;
 131
 132     default:
 133       cerr << ToolName << ": Unknown packet type #" << PacketType << "!\n";
 134       exit(1);
 135     }
 136   }
 137
 138   fclose(F);
 139 }
 140
 141
 142 // getFunctionCounts - This method is used by consumers of function counting
 143 // information.  If we do not directly have function count information, we
 144 // compute it from other, more refined, types of profile information.
 145 //
 146 void ProfileInfoLoader::getFunctionCounts(std::vector<std::pair<Function*,
 147                                                       unsigned> > &Counts) {
 148   if (FunctionCounts.empty()) {
 149     if (hasAccurateBlockCounts()) {
 150       // Synthesize function frequency information from the number of times
 151       // their entry blocks were executed.
 152       std::vector<std::pair<BasicBlock*, unsigned> > BlockCounts;
 153       getBlockCounts(BlockCounts);
 154
 155       for (unsigned i = 0, e = BlockCounts.size(); i != e; ++i)
 156         if (&BlockCounts[i].first->getParent()->getEntryBlock() ==
 157             BlockCounts[i].first)
 158           Counts.push_back(std::make_pair(BlockCounts[i].first->getParent(),
 159                                           BlockCounts[i].second));
 160     } else {
 161       cerr << "Function counts are not available!\n";
 162     }
 163     return;
 164   }
 165
 166   unsigned Counter = 0;
 167   for (Module::iterator I = M.begin(), E = M.end();
 168        I != E && Counter != FunctionCounts.size(); ++I)
 169     if (!I->isDeclaration())
 170       Counts.push_back(std::make_pair(I, FunctionCounts[Counter++]));
 171 }
 172
 173 // getBlockCounts - This method is used by consumers of block counting
 174 // information.  If we do not directly have block count information, we
 175 // compute it from other, more refined, types of profile information.
 176 //
 177 void ProfileInfoLoader::getBlockCounts(std::vector<std::pair<BasicBlock*,
 178                                                          unsigned> > &Counts) {
 179   if (BlockCounts.empty()) {
 180     if (hasAccurateEdgeCounts()) {
 181       // Synthesize block count information from edge frequency information.
 182       // The block execution frequency is equal to the sum of the execution
 183       // frequency of all outgoing edges from a block.
 184       //
 185       // If a block has no successors, this will not be correct, so we have to
 186       // special case it. :(
 187       std::vector<std::pair<Edge, unsigned> > EdgeCounts;
 188       getEdgeCounts(EdgeCounts);
 189
 190       std::map<BasicBlock*, unsigned> InEdgeFreqs;
 191
 192       BasicBlock *LastBlock = 0;
 193       TerminatorInst *TI = 0;
 194       for (unsigned i = 0, e = EdgeCounts.size(); i != e; ++i) {
 195         if (EdgeCounts[i].first.first != LastBlock) {
 196           LastBlock = EdgeCounts[i].first.first;
 197           TI = LastBlock->getTerminator();
 198           Counts.push_back(std::make_pair(LastBlock, 0));
 199         }
 200         Counts.back().second += EdgeCounts[i].second;
 201         unsigned SuccNum = EdgeCounts[i].first.second;
 202         if (SuccNum >= TI->getNumSuccessors()) {
 203           static bool Warned = false;
 204           if (!Warned) {
 205             cerr << "WARNING: profile info doesn't seem to match"
 206                  << " the program!\n";
 207             Warned = true;
 208           }
 209         } else {
 210           // If this successor has no successors of its own, we will never
 211           // compute an execution count for that block.  Remember the incoming
 212           // edge frequencies to add later.
 213           BasicBlock *Succ = TI->getSuccessor(SuccNum);
 214           if (Succ->getTerminator()->getNumSuccessors() == 0)
 215             InEdgeFreqs[Succ] += EdgeCounts[i].second;
 216         }
 217       }
 218
 219       // Now we have to accumulate information for those blocks without
 220       // successors into our table.
 221       for (std::map<BasicBlock*, unsigned>::iterator I = InEdgeFreqs.begin(),
 222              E = InEdgeFreqs.end(); I != E; ++I) {
 223         unsigned i = 0;
 224         for (; i != Counts.size() && Counts[i].first != I->first; ++i)
 225           /*empty*/;
 226         if (i == Counts.size()) Counts.push_back(std::make_pair(I->first, 0));
 227         Counts[i].second += I->second;
 228       }
 229
 230     } else {
 231       cerr << "Block counts are not available!\n";
 232     }
 233     return;
 234   }
 235
 236   unsigned Counter = 0;
 237   for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
 238     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
 239       Counts.push_back(std::make_pair(BB, BlockCounts[Counter++]));
 240       if (Counter == BlockCounts.size())
 241         return;
 242     }
 243 }
 244
 245 // getEdgeCounts - This method is used by consumers of edge counting
 246 // information.  If we do not directly have edge count information, we compute
 247 // it from other, more refined, types of profile information.
 248 //
 249 void ProfileInfoLoader::getEdgeCounts(std::vector<std::pair<Edge,
 250                                                   unsigned> > &Counts) {
 251   if (EdgeCounts.empty()) {
 252     cerr << "Edge counts not available, and no synthesis "
 253          << "is implemented yet!\n";
 254     return;
 255   }
 256
 257   unsigned Counter = 0;
 258   for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
 259     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
 260       for (unsigned i = 0, e = BB->getTerminator()->getNumSuccessors();
 261            i != e; ++i) {
 262         Counts.push_back(std::make_pair(Edge(BB, i), EdgeCounts[Counter++]));
 263         if (Counter == EdgeCounts.size())
 264           return;
 265       }
 266 }
 267
 268 // getBBTrace - This method is used by consumers of basic-block trace
 269 // information.
 270 //
 271 void ProfileInfoLoader::getBBTrace(std::vector<BasicBlock *> &Trace) {
 272   if (BBTrace.empty ()) {
 273     cerr << "Basic block trace is not available!\n";
 274     return;
 275   }
 276   cerr << "Basic block trace loading is not implemented yet!\n";
 277 }