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#include "llvm/CodeGen/LiveStackAnalysis.h" 17#include "llvm/ADT/Statistic.h" 18#include "llvm/CodeGen/LiveIntervalAnalysis.h" 19#include "llvm/CodeGen/Passes.h" 20#include "llvm/Support/Debug.h" 21#include "llvm/Support/raw_ostream.h" 22#include "llvm/Target/TargetRegisterInfo.h" 23#include <limits> 24using namespace llvm; 25 26#define DEBUG_TYPE "livestacks" 27 28char LiveStacks::ID = 0; 29INITIALIZE_PASS_BEGIN(LiveStacks, "livestacks", 30 "Live Stack Slot Analysis", false, false) 31INITIALIZE_PASS_DEPENDENCY(SlotIndexes) 32INITIALIZE_PASS_END(LiveStacks, "livestacks", 33 "Live Stack Slot Analysis", false, false) 34 35char &llvm::LiveStacksID = LiveStacks::ID; 36 37void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const { 38 AU.setPreservesAll(); 39 AU.addPreserved<SlotIndexes>(); 40 AU.addRequiredTransitive<SlotIndexes>(); 41 MachineFunctionPass::getAnalysisUsage(AU); 42} 43 44void LiveStacks::releaseMemory() { 45 // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd. 46 VNInfoAllocator.Reset(); 47 S2IMap.clear(); 48 S2RCMap.clear(); 49} 50 51bool LiveStacks::runOnMachineFunction(MachineFunction &MF) { 52 TRI = MF.getTarget().getRegisterInfo(); 53 // FIXME: No analysis is being done right now. We are relying on the 54 // register allocators to provide the information. 55 return false; 56} 57 58LiveInterval & 59LiveStacks::getOrCreateInterval(int Slot, const TargetRegisterClass *RC) { 60 assert(Slot >= 0 && "Spill slot indice must be >= 0"); 61 SS2IntervalMap::iterator I = S2IMap.find(Slot); 62 if (I == S2IMap.end()) { 63 I = S2IMap.insert(I, std::make_pair(Slot, 64 LiveInterval(TargetRegisterInfo::index2StackSlot(Slot), 0.0F))); 65 S2RCMap.insert(std::make_pair(Slot, RC)); 66 } else { 67 // Use the largest common subclass register class. 68 const TargetRegisterClass *OldRC = S2RCMap[Slot]; 69 S2RCMap[Slot] = TRI->getCommonSubClass(OldRC, RC); 70 } 71 return I->second; 72} 73 74/// print - Implement the dump method. 75void LiveStacks::print(raw_ostream &OS, const Module*) const { 76 77 OS << "********** INTERVALS **********\n"; 78 for (const_iterator I = begin(), E = end(); I != E; ++I) { 79 I->second.print(OS); 80 int Slot = I->first; 81 const TargetRegisterClass *RC = getIntervalRegClass(Slot); 82 if (RC) 83 OS << " [" << RC->getName() << "]\n"; 84 else 85 OS << " [Unknown]\n"; 86 } 87} 88