1 //===-- LiveStackAnalysis.cpp - Live Stack Slot Analysis ------------------===// 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 // This file implements the live stack slot analysis pass. It is analogous to 11 // live interval analysis except it's analyzing liveness of stack slots rather 12 // than registers. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #define DEBUG_TYPE "livestacks" 17 #include "llvm/CodeGen/LiveStackAnalysis.h" 18 #include "llvm/CodeGen/LiveIntervalAnalysis.h" 19 #include "llvm/CodeGen/Passes.h" 20 #include "llvm/Target/TargetRegisterInfo.h" 21 #include "llvm/Support/Debug.h" 22 #include "llvm/Support/raw_ostream.h" 23 #include "llvm/ADT/Statistic.h" 24 #include <limits> 25 using namespace llvm; 26 27 char LiveStacks::ID = 0; 28 INITIALIZE_PASS(LiveStacks, "livestacks", 29 "Live Stack Slot Analysis", false, false) 30 31 char &llvm::LiveStacksID = LiveStacks::ID; 32 33 void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const { 34 AU.setPreservesAll(); 35 AU.addPreserved<SlotIndexes>(); 36 AU.addRequiredTransitive<SlotIndexes>(); 37 MachineFunctionPass::getAnalysisUsage(AU); 38 } 39 40 void LiveStacks::releaseMemory() { 41 // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd. 42 VNInfoAllocator.Reset(); 43 S2IMap.clear(); 44 S2RCMap.clear(); 45 } 46 47 bool LiveStacks::runOnMachineFunction(MachineFunction &MF) { 48 TRI = MF.getTarget().getRegisterInfo(); 49 // FIXME: No analysis is being done right now. We are relying on the 50 // register allocators to provide the information. 51 return false; 52 } 53 54 LiveInterval & 55 LiveStacks::getOrCreateInterval(int Slot, const TargetRegisterClass *RC) { 56 assert(Slot >= 0 && "Spill slot indice must be >= 0"); 57 SS2IntervalMap::iterator I = S2IMap.find(Slot); 58 if (I == S2IMap.end()) { 59 I = S2IMap.insert(I, std::make_pair(Slot, 60 LiveInterval(TargetRegisterInfo::index2StackSlot(Slot), 0.0F))); 61 S2RCMap.insert(std::make_pair(Slot, RC)); 62 } else { 63 // Use the largest common subclass register class. 64 const TargetRegisterClass *OldRC = S2RCMap[Slot]; 65 S2RCMap[Slot] = TRI->getCommonSubClass(OldRC, RC); 66 } 67 return I->second; 68 } 69 70 /// print - Implement the dump method. 71 void LiveStacks::print(raw_ostream &OS, const Module*) const { 72 73 OS << "********** INTERVALS **********\n"; 74 for (const_iterator I = begin(), E = end(); I != E; ++I) { 75 I->second.print(OS); 76 int Slot = I->first; 77 const TargetRegisterClass *RC = getIntervalRegClass(Slot); 78 if (RC) 79 OS << " [" << RC->getName() << "]\n"; 80 else 81 OS << " [Unknown]\n"; 82 } 83 } 84
