llvm-6502/lib/Analysis/BlockFrequencyInfo.cpp
2011-08-03 21:30:57 +00:00

60 lines
2.0 KiB
C++

//=======-------- BlockFrequencyInfo.cpp - Block Frequency Analysis -------=======//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Loops should be simplified before this analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/InitializePasses.h"
#include "llvm/Analysis/BlockFrequencyImpl.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
using namespace llvm;
INITIALIZE_PASS_BEGIN(BlockFrequencyInfo, "block-freq", "Block Frequency Analysis",
true, true)
INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
INITIALIZE_PASS_END(BlockFrequencyInfo, "block-freq", "Block Frequency Analysis",
true, true)
char BlockFrequencyInfo::ID = 0;
BlockFrequencyInfo::BlockFrequencyInfo() : FunctionPass(ID) {
initializeBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
BFI = new BlockFrequencyImpl<BasicBlock, Function, BranchProbabilityInfo>();
}
BlockFrequencyInfo::~BlockFrequencyInfo() {
delete BFI;
}
void BlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<BranchProbabilityInfo>();
AU.setPreservesAll();
}
bool BlockFrequencyInfo::runOnFunction(Function &F) {
BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
BFI->doFunction(&F, &BPI);
return false;
}
/// getblockFreq - Return block frequency. Return 0 if we don't have the
/// information. Please note that initial frequency is equal to 1024. It means
/// that we should not rely on the value itself, but only on the comparison to
/// the other block frequencies. We do this to avoid using of floating points.
///
BlockFrequency BlockFrequencyInfo::getBlockFreq(BasicBlock *BB) const {
return BFI->getBlockFreq(BB);
}