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/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.ir;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Deque;
import java.util.List;
import jdk.nashorn.internal.codegen.types.Type;
/**
* Lexical context that keeps track of optimistic assumptions (if any)
* made during code generation. Used from Attr and FinalizeTypes
*/
public class OptimisticLexicalContext extends LexicalContext {
private final boolean isEnabled;
class Assumption {
Symbol symbol;
Type type;
Assumption(final Symbol symbol, final Type type) {
this.symbol = symbol;
this.type = type;
}
@Override
public String toString() {
return symbol.getName() + "=" + type;
}
}
/** Optimistic assumptions that could be made per function */
private final Deque<List<Assumption>> optimisticAssumptions = new ArrayDeque<>();
/**
* Constructor
* @param isEnabled are optimistic types enabled?
*/
public OptimisticLexicalContext(final boolean isEnabled) {
super();
this.isEnabled = isEnabled;
}
/**
* Are optimistic types enabled
* @return true if optimistic types
*/
public boolean isEnabled() {
return isEnabled;
}
/**
* Log an optimistic assumption during codegen
* TODO : different parameters and more info about the assumption for future profiling
* needs
* @param symbol symbol
* @param type type
*/
public void logOptimisticAssumption(final Symbol symbol, final Type type) {
if (isEnabled) {
final List<Assumption> peek = optimisticAssumptions.peek();
peek.add(new Assumption(symbol, type));
}
}
/**
* Get the list of optimistic assumptions made
* @return optimistic assumptions
*/
public List<Assumption> getOptimisticAssumptions() {
return Collections.unmodifiableList(optimisticAssumptions.peek());
}
/**
* Does this method have optimistic assumptions made during codegen?
* @return true if optimistic assumptions were made
*/
public boolean hasOptimisticAssumptions() {
return !optimisticAssumptions.isEmpty() && !getOptimisticAssumptions().isEmpty();
}
@Override
public <T extends LexicalContextNode> T push(final T node) {
if (isEnabled) {
if(node instanceof FunctionNode) {
optimisticAssumptions.push(new ArrayList<Assumption>());
}
}
return super.push(node);
}
@Override
public <T extends LexicalContextNode> T pop(final T node) {
final T popped = super.pop(node);
if (isEnabled) {
if(node instanceof FunctionNode) {
optimisticAssumptions.pop();
}
}
return popped;
}
}
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