llvm-6502/lib/Analysis/ProfileInfoLoader.cpp
Chris Lattner dbbbfef165 If we have edge counts, we can produce block counts. I've verified that
using an edge profile to produce block counts gives the exact same numbers
as using a block count directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12232 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-08 20:03:52 +00:00

266 lines
9.3 KiB
C++

//===- ProfileInfoLoad.cpp - Load profile information from disk -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The ProfileInfoLoader class is used to load and represent profiling
// information read in from the dump file.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ProfileInfoLoader.h"
#include "llvm/Module.h"
#include "llvm/InstrTypes.h"
#include <cstdio>
#include <map>
using namespace llvm;
enum ProfilingType {
ArgumentInfo = 1, // The command line argument block
FunctionInfo = 2, // Function profiling information
BlockInfo = 3, // Block profiling information
EdgeInfo = 4, // Edge profiling information
};
// ByteSwap - Byteswap 'Var' if 'Really' is true.
//
static inline unsigned ByteSwap(unsigned Var, bool Really) {
if (!Really) return Var;
return ((Var & (255<< 0)) << 24) |
((Var & (255<< 8)) << 8) |
((Var & (255<<16)) >> 8) |
((Var & (255<<24)) >> 24);
}
static void ReadProfilingBlock(const char *ToolName, FILE *F,
bool ShouldByteSwap,
std::vector<unsigned> &Data) {
// Read the number of entries...
unsigned NumEntries;
if (fread(&NumEntries, sizeof(unsigned), 1, F) != 1) {
std::cerr << ToolName << ": data packet truncated!\n";
perror(0);
exit(1);
}
NumEntries = ByteSwap(NumEntries, ShouldByteSwap);
// Read the counts...
std::vector<unsigned> TempSpace(NumEntries);
// Read in the block of data...
if (fread(&TempSpace[0], sizeof(unsigned)*NumEntries, 1, F) != 1) {
std::cerr << ToolName << ": data packet truncated!\n";
perror(0);
exit(1);
}
// Make sure we have enough space...
if (Data.size() < NumEntries)
Data.resize(NumEntries);
// Accumulate the data we just read into the data.
if (!ShouldByteSwap) {
for (unsigned i = 0; i != NumEntries; ++i)
Data[i] += TempSpace[i];
} else {
for (unsigned i = 0; i != NumEntries; ++i)
Data[i] += ByteSwap(TempSpace[i], true);
}
}
// ProfileInfoLoader ctor - Read the specified profiling data file, exiting the
// program if the file is invalid or broken.
//
ProfileInfoLoader::ProfileInfoLoader(const char *ToolName,
const std::string &Filename,
Module &TheModule) : M(TheModule) {
FILE *F = fopen(Filename.c_str(), "r");
if (F == 0) {
std::cerr << ToolName << ": Error opening '" << Filename << "': ";
perror(0);
exit(1);
}
// Keep reading packets until we run out of them.
unsigned PacketType;
while (fread(&PacketType, sizeof(unsigned), 1, F) == 1) {
// If the low eight bits of the packet are zero, we must be dealing with an
// endianness mismatch. Byteswap all words read from the profiling
// information.
bool ShouldByteSwap = (char)PacketType == 0;
PacketType = ByteSwap(PacketType, ShouldByteSwap);
switch (PacketType) {
case ArgumentInfo: {
unsigned ArgLength;
if (fread(&ArgLength, sizeof(unsigned), 1, F) != 1) {
std::cerr << ToolName << ": arguments packet truncated!\n";
perror(0);
exit(1);
}
ArgLength = ByteSwap(ArgLength, ShouldByteSwap);
// Read in the arguments...
std::vector<char> Chars(ArgLength+4);
if (ArgLength)
if (fread(&Chars[0], (ArgLength+3) & ~3, 1, F) != 1) {
std::cerr << ToolName << ": arguments packet truncated!\n";
perror(0);
exit(1);
}
CommandLines.push_back(std::string(&Chars[0], &Chars[ArgLength]));
break;
}
case FunctionInfo:
ReadProfilingBlock(ToolName, F, ShouldByteSwap, FunctionCounts);
break;
case BlockInfo:
ReadProfilingBlock(ToolName, F, ShouldByteSwap, BlockCounts);
break;
case EdgeInfo:
ReadProfilingBlock(ToolName, F, ShouldByteSwap, EdgeCounts);
break;
default:
std::cerr << ToolName << ": Unknown packet type #" << PacketType << "!\n";
exit(1);
}
}
fclose(F);
}
// getFunctionCounts - This method is used by consumers of function counting
// information. If we do not directly have function count information, we
// compute it from other, more refined, types of profile information.
//
void ProfileInfoLoader::getFunctionCounts(std::vector<std::pair<Function*,
unsigned> > &Counts) {
if (FunctionCounts.empty()) {
if (hasAccurateBlockCounts()) {
// Synthesize function frequency information from the number of times
// their entry blocks were executed.
std::vector<std::pair<BasicBlock*, unsigned> > BlockCounts;
getBlockCounts(BlockCounts);
for (unsigned i = 0, e = BlockCounts.size(); i != e; ++i)
if (&BlockCounts[i].first->getParent()->front() == BlockCounts[i].first)
Counts.push_back(std::make_pair(BlockCounts[i].first->getParent(),
BlockCounts[i].second));
} else {
std::cerr << "Function counts are not available!\n";
}
return;
}
unsigned Counter = 0;
for (Module::iterator I = M.begin(), E = M.end();
I != E && Counter != FunctionCounts.size(); ++I)
if (!I->isExternal())
Counts.push_back(std::make_pair(I, FunctionCounts[Counter++]));
}
// getBlockCounts - This method is used by consumers of block counting
// information. If we do not directly have block count information, we
// compute it from other, more refined, types of profile information.
//
void ProfileInfoLoader::getBlockCounts(std::vector<std::pair<BasicBlock*,
unsigned> > &Counts) {
if (BlockCounts.empty()) {
if (hasAccurateEdgeCounts()) {
// Synthesize block count information from edge frequency information.
// The block execution frequency is equal to the sum of the execution
// frequency of all outgoing edges from a block.
//
// If a block has no successors, this will not be correct, so we have to
// special case it. :(
std::vector<std::pair<Edge, unsigned> > EdgeCounts;
getEdgeCounts(EdgeCounts);
std::map<BasicBlock*, unsigned> InEdgeFreqs;
BasicBlock *LastBlock = 0;
TerminatorInst *TI = 0;
for (unsigned i = 0, e = EdgeCounts.size(); i != e; ++i) {
if (EdgeCounts[i].first.first != LastBlock) {
LastBlock = EdgeCounts[i].first.first;
TI = LastBlock->getTerminator();
Counts.push_back(std::make_pair(LastBlock, 0));
}
Counts.back().second += EdgeCounts[i].second;
unsigned SuccNum = EdgeCounts[i].first.second;
if (SuccNum >= TI->getNumSuccessors()) {
static bool Warned = false;
if (!Warned) {
std::cerr << "WARNING: profile info doesn't seem to match"
<< " the program!\n";
Warned = true;
}
} else {
// If this successor has no successors of its own, we will never
// compute an execution count for that block. Remember the incoming
// edge frequencies to add later.
BasicBlock *Succ = TI->getSuccessor(SuccNum);
if (Succ->getTerminator()->getNumSuccessors() == 0)
InEdgeFreqs[Succ] += EdgeCounts[i].second;
}
}
// Now we have to accumulate information for those blocks without
// successors into our table.
for (std::map<BasicBlock*, unsigned>::iterator I = InEdgeFreqs.begin(),
E = InEdgeFreqs.end(); I != E; ++I) {
unsigned i = 0;
for (; i != Counts.size() && Counts[i].first != I->first; ++i)
/*empty*/;
if (i == Counts.size()) Counts.push_back(std::make_pair(I->first, 0));
Counts[i].second += I->second;
}
} else {
std::cerr << "Block counts are not available!\n";
}
return;
}
unsigned Counter = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
Counts.push_back(std::make_pair(BB, BlockCounts[Counter++]));
if (Counter == BlockCounts.size())
return;
}
}
// getEdgeCounts - This method is used by consumers of edge counting
// information. If we do not directly have edge count information, we compute
// it from other, more refined, types of profile information.
//
void ProfileInfoLoader::getEdgeCounts(std::vector<std::pair<Edge,
unsigned> > &Counts) {
if (EdgeCounts.empty()) {
std::cerr << "Edge counts not available, and no synthesis "
<< "is implemented yet!\n";
return;
}
unsigned Counter = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (unsigned i = 0, e = BB->getTerminator()->getNumSuccessors();
i != e; ++i) {
Counts.push_back(std::make_pair(Edge(BB, i), EdgeCounts[Counter++]));
if (Counter == EdgeCounts.size())
return;
}
}