org.snapscript.dx.ssa.SetFactory Maven / Gradle / Ivy
/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.snapscript.dx.ssa;
import org.snapscript.dx.util.BitIntSet;
import org.snapscript.dx.util.IntSet;
import org.snapscript.dx.util.ListIntSet;
/**
* Makes int sets for various parts of the optimizer.
*/
public final class SetFactory {
/**
* BitIntSet/ListIntSet threshold for dominance frontier sets. These
* sets are kept per basic block until phi placement and tend to be,
* like the CFG itself, very sparse at large sizes.
*
* A value of 3072 here is somewhere around 1.125mb of total bitset size.
*/
private static final int DOMFRONT_SET_THRESHOLD_SIZE = 3072;
/**
* BitIntSet/ListIntSet threshold for interference graph sets. These
* sets are kept per register until register allocation is done.
*
* A value of 3072 here is somewhere around 1.125mb of total bitset size.
*/
private static final int INTERFERENCE_SET_THRESHOLD_SIZE = 3072;
/**
* BitIntSet/ListIntSet threshold for the live in/out sets kept by
* {@link SsaBasicBlock}. These are sets of SSA registers kept per basic
* block during register allocation.
*
* The total size of a bitset for this would be the count of blocks
* times the size of registers. The threshold value here is merely
* the register count, which is typically on the order of the block
* count as well.
*/
private static final int LIVENESS_SET_THRESHOLD_SIZE = 3072;
/**
* Make IntSet for the dominance-frontier sets.
*
* @param szBlocks {@code >=0;} count of basic blocks in method
* @return {@code non-null;} appropriate set
*/
/*package*/ static IntSet makeDomFrontSet(int szBlocks) {
return szBlocks <= DOMFRONT_SET_THRESHOLD_SIZE
? new BitIntSet(szBlocks)
: new ListIntSet();
}
/**
* Make IntSet for the interference graph sets. Public because
* InterferenceGraph is in another package.
*
* @param countRegs {@code >=0;} count of SSA registers used in method
* @return {@code non-null;} appropriate set
*/
public static IntSet makeInterferenceSet(int countRegs) {
return countRegs <= INTERFERENCE_SET_THRESHOLD_SIZE
? new BitIntSet(countRegs)
: new ListIntSet();
}
/**
* Make IntSet for register live in/out sets.
*
* @param countRegs {@code >=0;} count of SSA registers used in method
* @return {@code non-null;} appropriate set
*/
/*package*/ static IntSet makeLivenessSet(int countRegs) {
return countRegs <= LIVENESS_SET_THRESHOLD_SIZE
? new BitIntSet(countRegs)
: new ListIntSet();
}
}