lib/CodeGen/LiveStackAnalysis.cpp

   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 static RegisterPass<LiveStacks> X("livestacks", "Live Stack Slot Analysis");
  29
  30 void LiveStacks::scaleNumbering(int factor) {
  31   // Scale the intervals.
  32   for (iterator LI = begin(), LE = end(); LI != LE; ++LI) {
  33     LI->second.scaleNumbering(factor);
  34   }
  35 }
  36
  37 void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
  38   AU.setPreservesAll();
  39   MachineFunctionPass::getAnalysisUsage(AU);
  40 }
  41
  42 void LiveStacks::releaseMemory() {
  43   // Release VNInfo memroy regions after all VNInfo objects are dtor'd.
  44   VNInfoAllocator.Reset();
  45   S2IMap.clear();
  46   S2RCMap.clear();
  47 }
  48
  49 bool LiveStacks::runOnMachineFunction(MachineFunction &) {
  50   // FIXME: No analysis is being done right now. We are relying on the
  51   // register allocators to provide the information.
  52   return false;
  53 }
  54
  55 /// print - Implement the dump method.
  56 void LiveStacks::print(raw_ostream &OS, const Module*) const {
  57
  58   OS << "********** INTERVALS **********\n";
  59   for (const_iterator I = begin(), E = end(); I != E; ++I) {
  60     I->second.print(OS);
  61     int Slot = I->first;
  62     const TargetRegisterClass *RC = getIntervalRegClass(Slot);
  63     if (RC)
  64       OS << " [" << RC->getName() << "]\n";
  65     else
  66       OS << " [Unknown]\n";
  67   }
  68 }