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Complete liveness analyzer (not tested)

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konsoletyper 2014-01-15 17:38:14 +04:00
parent c8ac2a8b98
commit c704956ca1
1 changed files with 55 additions and 26 deletions
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81
teavm-core/src/main/java/org/teavm/model/util/LivenessAnalyzer.java
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@ -15,28 +15,71 @@
*/
package org.teavm.model.util;
import java.util.ArrayList;
import java.util.List;
import org.teavm.common.DominatorTree;
import java.util.ArrayDeque;
import java.util.BitSet;
import java.util.Deque;
import org.teavm.common.Graph;
import org.teavm.common.GraphUtils;
import org.teavm.model.Program;
import org.teavm.model.*;
/**
*
* @author Alexey Andreev
*/
public class LivenessAnalyzer {
private BackNode[] backNodeGraph;
private BitSet[] liveVars;
private int[] domLeft;
private int[] domRight;
public boolean liveIn(int block, int var) {
return liveVars[block].get(var);
}
public void analyze(Program program) {
Graph cfg = ProgramUtils.buildControlFlowGraph(program);
DominatorTree domTree = GraphUtils.buildDominatorTree(cfg);
Graph domGraph = GraphUtils.buildDominatorGraph(domTree, cfg.size());
computeDomLeftRight(domGraph);
prepareBackGraph(domTree, cfg);
computeDomLeftRight(GraphUtils.buildDominatorGraph(GraphUtils.buildDominatorTree(cfg), cfg.size()));
liveVars = new BitSet[cfg.size()];
for (int i = 0; i < liveVars.length; ++i) {
liveVars[i] = new BitSet(program.basicBlockCount());
}
UsageExtractor usageExtractor = new UsageExtractor();
DefinitionExtractor defExtractor = new DefinitionExtractor();
Deque<Task> stack = new ArrayDeque<>();
int[] definitions = new int[program.variableCount()];
for (int i = 0; i < program.basicBlockCount(); ++i) {
BasicBlock block = program.basicBlockAt(i);
for (Instruction insn : block.getInstructions()) {
insn.acceptVisitor(usageExtractor);
for (Variable var : usageExtractor.getUsedVariables()) {
Task task = new Task();
task.block = i;
task.var = var.getIndex();
stack.push(task);
}
insn.acceptVisitor(defExtractor);
for (Variable var : defExtractor.getDefinedVariables()) {
definitions[var.getIndex()] = i;
}
}
for (Phi phi : block.getPhis()) {
definitions[phi.getReceiver().getIndex()] = i;
}
}
while (stack.isEmpty()) {
Task task = stack.pop();
if (liveVars[task.block].get(task.var) || !dominates(definitions[task.var], task.block)) {
continue;
}
liveVars[task.block].set(task.var, true);
for (int pred : cfg.incomingEdges(task.block)) {
Task nextTask = new Task();
nextTask.block = pred;
nextTask.var = task.var;
stack.push(nextTask);
}
}
}
private void computeDomLeftRight(Graph domGraph) {
@ -66,26 +109,12 @@ public class LivenessAnalyzer {
}
}
private void prepareBackGraph(DominatorTree domTree, Graph cfg) {
backNodeGraph = new BackNode[cfg.size() * 2];
int[] stack = new int[cfg.size() * 2];
int top = 0;
for (int i = 0; i < cfg.size(); ++i) {
if (cfg.outgoingEdgesCount(i) == 0) {
stack[top++] = i;
}
}
while (top > 0) {
}
}
private boolean dominates(int a, int b) {
return domLeft[a] <= domLeft[b] && domRight[a] >= domRight[b];
}
private static class BackNode {
final List<BackNode> successors = new ArrayList<>();
int blockIndex;
private static class Task {
int block;
int var;
}
}