Fixes issues in if statement AST optimizer

This commit is contained in:
konsoletyper 2014-01-30 17:13:24 +04:00
parent 16d11909ea
commit 692bfdd731
2 changed files with 81 additions and 66 deletions

View File

@ -301,94 +301,101 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
return result; return result;
} }
private void eliminateRedundantBreaks(List<Statement> statements, Set<IdentifiedStatement> currentExits, private void eliminateRedundantBreaks(List<Statement> statements, IdentifiedStatement exit) {
Set<IdentifiedStatement> exits) {
if (statements.isEmpty()) { if (statements.isEmpty()) {
return; return;
} }
Statement last = statements.get(statements.size() - 1); Statement last = statements.get(statements.size() - 1);
if (last instanceof BreakStatement) { if (last instanceof BreakStatement && exit != null) {
IdentifiedStatement target = ((BreakStatement)last).getTarget(); IdentifiedStatement target = ((BreakStatement)last).getTarget();
if (exits.contains(target)) { if (exit == target) {
statements.remove(statements.size() - 1); statements.remove(statements.size() - 1);
} }
} }
if (statements.isEmpty()) { if (statements.isEmpty()) {
return; return;
} }
Set<IdentifiedStatement> nestedExits = new HashSet<>();
nestedExits.addAll(currentExits);
for (int i = 0; i < statements.size(); ++i) { for (int i = 0; i < statements.size(); ++i) {
if (i == statements.size() - 1) {
nestedExits.addAll(exits);
}
Statement stmt = statements.get(i); Statement stmt = statements.get(i);
if (stmt instanceof ConditionalStatement) { if (stmt instanceof ConditionalStatement) {
ConditionalStatement cond = (ConditionalStatement)stmt; ConditionalStatement cond = (ConditionalStatement)stmt;
last = cond.getConsequent().get(cond.getConsequent().size() - 1); check_conditional: {
if (last instanceof BreakStatement) { last = cond.getConsequent().isEmpty() ? null :
BreakStatement breakStmt = (BreakStatement)last; cond.getConsequent().get(cond.getConsequent().size() - 1);
if (currentExits.contains(breakStmt.getTarget()) || exits.contains(breakStmt.getTarget())) { if (last instanceof BreakStatement) {
int refs = referencedStatements.get(breakStmt.getTarget()); BreakStatement breakStmt = (BreakStatement)last;
referencedStatements.put(breakStmt.getTarget(), refs - 1); if (exit != null && exit == breakStmt.getTarget()) {
cond.getConsequent().remove(cond.getConsequent().size() - 1); int refs = referencedStatements.get(breakStmt.getTarget());
List<Statement> remaining = statements.subList(i + 1, statements.size()); referencedStatements.put(breakStmt.getTarget(), refs - 1);
cond.getAlternative().addAll(remaining); cond.getConsequent().remove(cond.getConsequent().size() - 1);
remaining.clear(); List<Statement> remaining = statements.subList(i + 1, statements.size());
visit(cond); cond.getAlternative().addAll(remaining);
if (resultStmt == cond) { remaining.clear();
eliminateRedundantBreaks(cond.getConsequent(), break check_conditional;
Collections.<IdentifiedStatement>emptySet(), nestedExits); }
eliminateRedundantBreaks(cond.getAlternative(), }
Collections.<IdentifiedStatement>emptySet(), nestedExits); last = cond.getAlternative().isEmpty() ? null :
} else { cond.getAlternative().get(cond.getAlternative().size() - 1);
statements.set(i, resultStmt); if (last instanceof BreakStatement) {
BreakStatement breakStmt = (BreakStatement)last;
if (exit != null && exit == breakStmt.getTarget()) {
int refs = referencedStatements.get(breakStmt.getTarget());
referencedStatements.put(breakStmt.getTarget(), refs - 1);
cond.getAlternative().remove(cond.getConsequent().size() - 1);
List<Statement> remaining = statements.subList(i + 1, statements.size());
cond.getConsequent().addAll(remaining);
remaining.clear();
break check_conditional;
} }
break;
} }
} }
last = cond.getAlternative().isEmpty() ? null : if (i == statements.size() - 1) {
cond.getAlternative().get(cond.getAlternative().size() - 1); eliminateRedundantBreaks(cond.getConsequent(), exit);
if (last instanceof BreakStatement) { eliminateRedundantBreaks(cond.getAlternative(), exit);
BreakStatement breakStmt = (BreakStatement)last; }
if (currentExits.contains(breakStmt.getTarget()) || exits.contains(breakStmt.getTarget())) { normalizeConditional(cond);
int refs = referencedStatements.get(breakStmt.getTarget()); if (cond.getConsequent().size() == 1 && cond.getConsequent().get(0) instanceof ConditionalStatement) {
referencedStatements.put(breakStmt.getTarget(), refs - 1); ConditionalStatement innerCond = (ConditionalStatement)cond.getConsequent().get(0);
cond.getAlternative().remove(cond.getConsequent().size() - 1); if (innerCond.getAlternative().isEmpty()) {
List<Statement> remaining = statements.subList(i + 1, statements.size()); if (cond.getAlternative().isEmpty()) {
cond.getConsequent().addAll(remaining); cond.getConsequent().clear();
remaining.clear(); cond.getConsequent().addAll(innerCond.getConsequent());
visit(cond); cond.setCondition(Expr.binary(BinaryOperation.AND, cond.getCondition(),
if (resultStmt == cond) { innerCond.getCondition()));
eliminateRedundantBreaks(cond.getConsequent(), } else {
Collections.<IdentifiedStatement>emptySet(), nestedExits); cond.setCondition(ExprOptimizer.invert(cond.getCondition()));
eliminateRedundantBreaks(cond.getAlternative(), cond.getConsequent().clear();
Collections.<IdentifiedStatement>emptySet(), nestedExits); cond.getConsequent().addAll(cond.getAlternative());
cond.getAlternative().clear();
cond.getAlternative().add(innerCond);
} }
statements.set(i, resultStmt); --i;
break;
} }
} }
} else if (stmt instanceof BlockStatement) { } else if (stmt instanceof BlockStatement) {
BlockStatement nestedBlock = (BlockStatement)stmt; BlockStatement nestedBlock = (BlockStatement)stmt;
eliminateRedundantBreaks(nestedBlock.getBody(), eliminateRedundantBreaks(nestedBlock.getBody(), nestedBlock);
Collections.<IdentifiedStatement>singleton(nestedBlock), nestedExits);
} else if (stmt instanceof WhileStatement) { } else if (stmt instanceof WhileStatement) {
WhileStatement whileStmt = (WhileStatement)stmt; WhileStatement whileStmt = (WhileStatement)stmt;
eliminateRedundantBreaks(whileStmt.getBody(), Collections.<IdentifiedStatement>emptySet(), eliminateRedundantBreaks(whileStmt.getBody(), null);
Collections.<IdentifiedStatement>emptySet());
} else if (stmt instanceof SwitchStatement) { } else if (stmt instanceof SwitchStatement) {
SwitchStatement switchStmt = (SwitchStatement)stmt; SwitchStatement switchStmt = (SwitchStatement)stmt;
for (SwitchClause clause : switchStmt.getClauses()) { for (SwitchClause clause : switchStmt.getClauses()) {
eliminateRedundantBreaks(clause.getBody(), Collections.<IdentifiedStatement>emptySet(), eliminateRedundantBreaks(clause.getBody(), null);
Collections.<IdentifiedStatement>emptySet());
} }
eliminateRedundantBreaks(switchStmt.getDefaultClause(), null, eliminateRedundantBreaks(switchStmt.getDefaultClause(), null);
Collections.<IdentifiedStatement>emptySet());
} }
} }
} }
private void normalizeConditional(ConditionalStatement stmt) {
if (stmt.getConsequent().isEmpty()) {
stmt.getConsequent().addAll(stmt.getAlternative());
stmt.getAlternative().clear();
stmt.setCondition(ExprOptimizer.invert(stmt.getCondition()));
}
}
@Override @Override
public void visit(SequentialStatement statement) { public void visit(SequentialStatement statement) {
List<Statement> statements = processSequence(statement.getSequence(), false); List<Statement> statements = processSequence(statement.getSequence(), false);
@ -453,8 +460,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
@Override @Override
public void visit(BlockStatement statement) { public void visit(BlockStatement statement) {
List<Statement> statements = processSequence(statement.getBody(), false); List<Statement> statements = processSequence(statement.getBody(), false);
eliminateRedundantBreaks(statements, Collections.<IdentifiedStatement>singleton(statement), eliminateRedundantBreaks(statements, statement);
Collections.<IdentifiedStatement>emptySet());
if (referencedStatements.get(statement).equals(0)) { if (referencedStatements.get(statement).equals(0)) {
SequentialStatement result = new SequentialStatement(); SequentialStatement result = new SequentialStatement();
result.getSequence().addAll(statements); result.getSequence().addAll(statements);

View File

@ -385,17 +385,26 @@ public class Renderer implements ExprVisitor, StatementVisitor {
@Override @Override
public void visit(ConditionalStatement statement) { public void visit(ConditionalStatement statement) {
try { try {
writer.append("if").ws().append("("); while (true) {
statement.getCondition().acceptVisitor(this); writer.append("if").ws().append("(");
writer.append(")").ws().append("{").softNewLine().indent(); statement.getCondition().acceptVisitor(this);
for (Statement part : statement.getConsequent()) { writer.append(")").ws().append("{").softNewLine().indent();
part.acceptVisitor(this); for (Statement part : statement.getConsequent()) {
}
if (!statement.getAlternative().isEmpty()) {
writer.outdent().append("}").ws().append("else").ws().append("{").indent().softNewLine();
for (Statement part : statement.getAlternative()) {
part.acceptVisitor(this); part.acceptVisitor(this);
} }
if (!statement.getAlternative().isEmpty()) {
writer.outdent().append("}").ws().append("else").ws();
if (statement.getAlternative().size() == 1 &&
statement.getAlternative().get(0) instanceof ConditionalStatement) {
statement = (ConditionalStatement)statement.getAlternative().get(0);
continue;
}
writer.append("{").indent().softNewLine();
for (Statement part : statement.getAlternative()) {
part.acceptVisitor(this);
}
}
break;
} }
writer.outdent().append("}").softNewLine(); writer.outdent().append("}").softNewLine();
} catch (IOException e) { } catch (IOException e) {