RegAllocFast.cpp

///
bool RAFast::runOnMachineFunction(MachineFunction &Fn) {
  DEBUG(dbgs() << "********** FAST REGISTER ALLOCATION **********\n"
               << "********** Function: "
               << ((Value*)Fn.getFunction())->getName() << '\n');
  MF = &Fn;
  MRI = &MF->getRegInfo();
  TM = &Fn.getTarget();
  TRI = TM->getRegisterInfo();
  TII = TM->getInstrInfo();

  UsedInInstr.resize(TRI->getNumRegs());
  Allocatable = TRI->getAllocatableSet(*MF);

  // initialize the virtual->physical register map to have a 'null'
  // mapping for all virtual registers
  unsigned LastVirtReg = MRI->getLastVirtReg();
  StackSlotForVirtReg.grow(LastVirtReg);

  // Loop over all of the basic blocks, eliminating virtual register references
  for (MachineFunction::iterator MBBi = Fn.begin(), MBBe = Fn.end();
       MBBi != MBBe; ++MBBi) {
    MBB = &*MBBi;
    AllocateBasicBlock();
  }

  // Make sure the set of used physregs is closed under subreg operations.
  MRI->closePhysRegsUsed(*TRI);

  // Add the clobber lists for all the instructions we skipped earlier.
  for (SmallPtrSet<const TargetInstrDesc*, 4>::const_iterator
       I = SkippedInstrs.begin(), E = SkippedInstrs.end(); I != E; ++I)
    if (const unsigned *Defs = (*I)->getImplicitDefs())
      while (*Defs)
        MRI->setPhysRegUsed(*Defs++);

  SkippedInstrs.clear();
  StackSlotForVirtReg.clear();
  LiveDbgValueMap.clear();
  return true;
}

FunctionPass *llvm::createFastRegisterAllocator() {
  return new RAFast();
}