llvm-6502/lib/CodeGen/PreAllocSplitting.cpp

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//===-- PreAllocSplitting.cpp - Pre-allocation Interval Spltting Pass. ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the machine instruction level pre-register allocation
// live interval splitting pass. It finds live interval barriers, i.e.
// instructions which will kill all physical registers in certain register
// classes, and split all live intervals which cross the barrier.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pre-alloc-split"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegisterCoalescer.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
namespace {
class VISIBILITY_HIDDEN PreAllocSplitting : public MachineFunctionPass {
// ProcessedBarriers - Register live interval barriers that have already
// been processed.
SmallPtrSet<MachineInstr*, 16> ProcessedBarriers;
// ActiveBarriers - Register live interval barriers that are currently
// being processed.
SmallSet<unsigned, 16> ActiveBarriers;
public:
static char ID;
PreAllocSplitting() : MachineFunctionPass(&ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
AU.addPreserved<MachineLoopInfo>();
AU.addPreserved<RegisterCoalescer>();
if (StrongPHIElim)
AU.addPreservedID(StrongPHIEliminationID);
else
AU.addPreservedID(PHIEliminationID);
AU.addPreservedID(TwoAddressInstructionPassID);
MachineFunctionPass::getAnalysisUsage(AU);
}
virtual void releaseMemory() {
ProcessedBarriers.clear();
ActiveBarriers.clear();
}
virtual const char *getPassName() const {
return "Pre-Register Allocaton Live Interval Splitting";
}
};
} // end anonymous namespace
char PreAllocSplitting::ID = 0;
static RegisterPass<PreAllocSplitting>
X("pre-alloc-splitting", "Pre-Register Allocation Live Interval Splitting");
const PassInfo *const llvm::PreAllocSplittingID = &X;
bool PreAllocSplitting::runOnMachineFunction(MachineFunction &MF) {
return false;
}