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> 25using namespace llvm; 26 27char LiveStacks::ID = 0; 28INITIALIZE_PASS_BEGIN(LiveStacks, "livestacks", 29 "Live Stack Slot Analysis", false, false) 30INITIALIZE_PASS_DEPENDENCY(SlotIndexes) 31INITIALIZE_PASS_END(LiveStacks, "livestacks", 32 "Live Stack Slot Analysis", false, false) 33 34char &llvm::LiveStacksID = LiveStacks::ID; 35 36void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const { 37 AU.setPreservesAll(); 38 AU.addPreserved<SlotIndexes>(); 39 AU.addRequiredTransitive<SlotIndexes>(); 40 MachineFunctionPass::getAnalysisUsage(AU); 41} 42 43void LiveStacks::releaseMemory() { 44 // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd. 45 VNInfoAllocator.Reset(); 46 S2IMap.clear(); 47 S2RCMap.clear(); 48} 49 50bool LiveStacks::runOnMachineFunction(MachineFunction &MF) { 51 TRI = MF.getTarget().getRegisterInfo(); 52 // FIXME: No analysis is being done right now. We are relying on the 53 // register allocators to provide the information. 54 return false; 55} 56 57LiveInterval & 58LiveStacks::getOrCreateInterval(int Slot, const TargetRegisterClass *RC) { 59 assert(Slot >= 0 && "Spill slot indice must be >= 0"); 60 SS2IntervalMap::iterator I = S2IMap.find(Slot); 61 if (I == S2IMap.end()) { 62 I = S2IMap.insert(I, std::make_pair(Slot, 63 LiveInterval(TargetRegisterInfo::index2StackSlot(Slot), 0.0F))); 64 S2RCMap.insert(std::make_pair(Slot, RC)); 65 } else { 66 // Use the largest common subclass register class. 67 const TargetRegisterClass *OldRC = S2RCMap[Slot]; 68 S2RCMap[Slot] = TRI->getCommonSubClass(OldRC, RC); 69 } 70 return I->second; 71} 72 73/// print - Implement the dump method. 74void LiveStacks::print(raw_ostream &OS, const Module*) const { 75 76 OS << "********** INTERVALS **********\n"; 77 for (const_iterator I = begin(), E = end(); I != E; ++I) { 78 I->second.print(OS); 79 int Slot = I->first; 80 const TargetRegisterClass *RC = getIntervalRegClass(Slot); 81 if (RC) 82 OS << " [" << RC->getName() << "]\n"; 83 else 84 OS << " [Unknown]\n"; 85 } 86} 87