| //===- ProfileInfo.cpp - Profile Info Interface ---------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the abstract ProfileInfo interface, and the default |
| // "no profile" implementation. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/Passes.h" |
| #include "llvm/Analysis/ProfileInfo.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/CFG.h" |
| #include "llvm/Support/Compiler.h" |
| #include <set> |
| using namespace llvm; |
| |
| // Register the ProfileInfo interface, providing a nice name to refer to. |
| static RegisterAnalysisGroup<ProfileInfo> Z("Profile Information"); |
| char ProfileInfo::ID = 0; |
| |
| ProfileInfo::~ProfileInfo() {} |
| |
| unsigned ProfileInfo::getExecutionCount(BasicBlock *BB) const { |
| pred_iterator PI = pred_begin(BB), PE = pred_end(BB); |
| |
| // Are there zero predecessors of this block? |
| if (PI == PE) { |
| // If this is the entry block, look for the Null -> Entry edge. |
| if (BB == &BB->getParent()->getEntryBlock()) |
| return getEdgeWeight(0, BB); |
| else |
| return 0; // Otherwise, this is a dead block. |
| } |
| |
| // Otherwise, if there are predecessors, the execution count of this block is |
| // the sum of the edge frequencies from the incoming edges. Note that if |
| // there are multiple edges from a predecessor to this block that we don't |
| // want to count its weight multiple times. For this reason, we keep track of |
| // the predecessors we've seen and only count them if we haven't run into them |
| // yet. |
| // |
| // We don't want to create an std::set unless we are dealing with a block that |
| // has a LARGE number of in-edges. Handle the common case of having only a |
| // few in-edges with special code. |
| // |
| BasicBlock *FirstPred = *PI; |
| unsigned Count = getEdgeWeight(FirstPred, BB); |
| ++PI; |
| if (PI == PE) return Count; // Quick exit for single predecessor blocks |
| |
| BasicBlock *SecondPred = *PI; |
| if (SecondPred != FirstPred) Count += getEdgeWeight(SecondPred, BB); |
| ++PI; |
| if (PI == PE) return Count; // Quick exit for two predecessor blocks |
| |
| BasicBlock *ThirdPred = *PI; |
| if (ThirdPred != FirstPred && ThirdPred != SecondPred) |
| Count += getEdgeWeight(ThirdPred, BB); |
| ++PI; |
| if (PI == PE) return Count; // Quick exit for three predecessor blocks |
| |
| std::set<BasicBlock*> ProcessedPreds; |
| ProcessedPreds.insert(FirstPred); |
| ProcessedPreds.insert(SecondPred); |
| ProcessedPreds.insert(ThirdPred); |
| for (; PI != PE; ++PI) |
| if (ProcessedPreds.insert(*PI).second) |
| Count += getEdgeWeight(*PI, BB); |
| return Count; |
| } |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // NoProfile ProfileInfo implementation |
| // |
| |
| namespace { |
| struct VISIBILITY_HIDDEN NoProfileInfo |
| : public ImmutablePass, public ProfileInfo { |
| static char ID; // Class identification, replacement for typeinfo |
| NoProfileInfo() : ImmutablePass((intptr_t)&ID) {} |
| }; |
| } // End of anonymous namespace |
| |
| char NoProfileInfo::ID = 0; |
| // Register this pass... |
| static RegisterPass<NoProfileInfo> |
| X("no-profile", "No Profile Information", false, true); |
| |
| // Declare that we implement the ProfileInfo interface |
| static RegisterAnalysisGroup<ProfileInfo, true> Y(X); |
| |
| ImmutablePass *llvm::createNoProfileInfoPass() { return new NoProfileInfo(); } |