//===- MachineLoopInfo.cpp - Natural Loop Calculator ----------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines the MachineLoopInfo class that is used to identify natural // loops and determine the loop depth of various nodes of the CFG. Note that // the loops identified may actually be several natural loops that share the // same header node... not just a single natural loop. // //===----------------------------------------------------------------------===// #include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/Passes.h" #include "llvm/Analysis/LoopInfoImpl.h" #include "llvm/Support/Debug.h" using namespace llvm; // Explicitly instantiate methods in LoopInfoImpl.h for MI-level Loops. template class llvm::LoopBase<MachineBasicBlock, MachineLoop>; template class llvm::LoopInfoBase<MachineBasicBlock, MachineLoop>; char MachineLoopInfo::ID = 0; INITIALIZE_PASS_BEGIN(MachineLoopInfo, "machine-loops", "Machine Natural Loop Construction", true, true) INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) INITIALIZE_PASS_END(MachineLoopInfo, "machine-loops", "Machine Natural Loop Construction", true, true) char &llvm::MachineLoopInfoID = MachineLoopInfo::ID; bool MachineLoopInfo::runOnMachineFunction(MachineFunction &) { releaseMemory(); LI.Analyze(getAnalysis<MachineDominatorTree>().getBase()); return false; } void MachineLoopInfo::getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesAll(); AU.addRequired<MachineDominatorTree>(); MachineFunctionPass::getAnalysisUsage(AU); } MachineBasicBlock *MachineLoop::getTopBlock() { MachineBasicBlock *TopMBB = getHeader(); MachineFunction::iterator Begin = TopMBB->getParent()->begin(); if (TopMBB != Begin) { MachineBasicBlock *PriorMBB = prior(MachineFunction::iterator(TopMBB)); while (contains(PriorMBB)) { TopMBB = PriorMBB; if (TopMBB == Begin) break; PriorMBB = prior(MachineFunction::iterator(TopMBB)); } } return TopMBB; } MachineBasicBlock *MachineLoop::getBottomBlock() { MachineBasicBlock *BotMBB = getHeader(); MachineFunction::iterator End = BotMBB->getParent()->end(); if (BotMBB != prior(End)) { MachineBasicBlock *NextMBB = llvm::next(MachineFunction::iterator(BotMBB)); while (contains(NextMBB)) { BotMBB = NextMBB; if (BotMBB == llvm::next(MachineFunction::iterator(BotMBB))) break; NextMBB = llvm::next(MachineFunction::iterator(BotMBB)); } } return BotMBB; } #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void MachineLoop::dump() const { print(dbgs()); } #endif