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/ADT/Statistic.h"
  23 #include <limits>
  24 using namespace llvm;
  25
  26 char LiveStacks::ID = 0;
  27 static RegisterPass<LiveStacks> X("livestacks", "Live Stack Slot Analysis");
  28
  29 void LiveStacks::scaleNumbering(int factor) {
  30   // Scale the intervals.
  31   for (iterator LI = begin(), LE = end(); LI != LE; ++LI) {
  32     LI->second.scaleNumbering(factor);
  33   }
  34 }
  35
  36 void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
  37   AU.setPreservesAll();
  38   MachineFunctionPass::getAnalysisUsage(AU);
  39 }
  40
  41 void LiveStacks::releaseMemory() {
  42   // Release VNInfo memroy regions after all VNInfo objects are dtor'd.
  43   VNInfoAllocator.Reset();
  44   S2IMap.clear();
  45   S2RCMap.clear();
  46 }
  47
  48 bool LiveStacks::runOnMachineFunction(MachineFunction &) {
  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 /// print - Implement the dump method.
  55 void LiveStacks::print(std::ostream &O, const Module*) const {
  56   O << "********** INTERVALS **********\n";
  57   for (const_iterator I = begin(), E = end(); I != E; ++I) {
  58     I->second.print(O);
  59     int Slot = I->first;
  60     const TargetRegisterClass *RC = getIntervalRegClass(Slot);
  61     if (RC)
  62       O << " [" << RC->getName() << "]\n";
  63     else
  64       O << " [Unknown]\n";
  65   }
  66 }