regAlloc.cpp

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/* Copyright 1994, LongView Technologies L.L.C. $Revision: 1.20 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
All rights reserved.

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    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
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          disclaimer in the documentation and/or other materials provided with the distribution.
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          from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT 
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# include "incls/_precompiled.incl"

# ifdef DELTA_COMPILER

# include "incls/_regAlloc.cpp.incl"

RegisterAllocator* theAllocator;


static int compare_pregBegs(PReg** a, PReg** b) {
  return (*a)->begBCI() - (*b)->begBCI();
}


static int compare_pregEnds(PReg** a, PReg** b) {
  return (*a)->endBCI() - (*b)->endBCI();
}


RegisterAllocator::RegisterAllocator() {
  theAllocator = this; 
  _stackLocs = new IntFreeList(2);
}


void RegisterAllocator::preAllocate(PReg* r) {
  r->allocateTo(Mapping::localTemporary(_stackLocs->allocate()));
}


void RegisterAllocator::allocate(GrowableArray<PReg*>* globals) {
  GrowableArray<PReg*>* regs = new GrowableArray<PReg*>(globals->length());
  int i = globals->length();
  while (i-- > 0) {
    PReg* r = globals->at(i);
    assert(r->ndefs() + r->nuses() > 0 || r->incorrectDU(), "PReg is unused");
    if (r->loc != unAllocated) {
      // already allocated
    } else if (r->isConstPReg()) {
      // don't allocate constants for now
    } else {
      // collect for later allocation
      regs->append(r);
    }
  }

  int len = regs->length();
  if (len > 0) {
    // sort begBCIs & distribute to scopes
    regs->sort(&compare_pregBegs);
    assert(regs->isEmpty() || regs->first()->begBCI() <= regs->last()->begBCI(), "wrong sort order");
    for (i = 0; i < len; i++) {
      PReg* r = regs->at(i);
      assert(r->begBCI() != IllegalBCI, "illegal begBCI");
      assert(r->endBCI() != IllegalBCI, "illegal endBCI");
      r->scope()->addToPRegsBegSorted(r);
    }

    // sort endBCIs & distribute to scopes
    regs->sort(&compare_pregEnds);
    assert(regs->isEmpty() || regs->first()->endBCI() <= regs->last()->endBCI(), "wrong sort order");
    for (i = 0; i < len; i++) {
      PReg* r = regs->at(i);
      r->scope()->addToPRegsEndSorted(r);
    }
    // do register allocation
    theCompiler->topScope->allocatePRegs(_stackLocs);

    // result
    if (CompilerDebug) cout(PrintRegAlloc)->print("%d (-2) stack locations allocated for %d PRegs\n", _stackLocs->length(), regs->length());
  }
}


# endif // DELTA_COMPILER

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