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Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
* Subject to the condition set forth below, permission is hereby granted to any
* person obtaining a copy of this software, associated documentation and/or
* data (collectively the "Software"), free of charge and under any and all
* copyright rights in the Software, and any and all patent rights owned or
* freely licensable by each licensor hereunder covering either (i) the
* unmodified Software as contributed to or provided by such licensor, or (ii)
* the Larger Works (as defined below), to deal in both
*
* (a) the Software, and
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* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
* one is included with the Software each a "Larger Work" to which the Software
* is contributed by such licensors),
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* without restriction, including without limitation the rights to copy, create
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* Software and the Larger Work(s), and to sublicense the foregoing rights on
* either these or other terms.
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* This license is subject to the following condition:
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* The above copyright notice and either this complete permission notice or at a
* minimum a reference to the UPL must be included in all copies or substantial
* portions of the Software.
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package com.oracle.truffle.api.instrumentation;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import com.oracle.truffle.api.instrumentation.InstrumentableNode.WrapperNode;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.nodes.NodeUtil;
import com.oracle.truffle.api.nodes.NodeVisitor;
import com.oracle.truffle.api.source.SourceSection;
/**
* Implements the default logic of searching for the nearest {@link Node node} to the given source
* character index according to the execution flow, that is tagged with the given tag.
*
* This code assumes that the Truffle Node hierarchy corresponds with the logical guest language
* AST structure.
*
* If this is not the case for a particular guest language,
* {@link InstrumentableNode#findNearestNodeAt(int, Set)} needs to be implemented, possibly with
* logic in this class applied to the language logical AST nodes.
*/
class DefaultNearestNodeSearch {
/**
* We have a source offset (the character index) and a context node given. The offset is in
* node's source. The context node is an instrumentable node, but may not have any particular
* tags. We're searching for an instrumentable node tagged with at least one of the given tags,
* which is nearest to the given offset according to the guest language execution flow. We find
* the nearest tagged {@link Node node} in following steps:
*
* - When the offset is inside the context node, we search for the first tagged parent node
* and call {@link #findChildTaggedNode(Node, int, Set, boolean)} to find a tagged child. If we
* find it, we return it, if not, we continue to search recursively for a tagged child of node's
* parent. If we encounter the first tagged parent node, return it, otherwise return tagged
* child found during the recursive process, if any.
* - When the offset is behind the context node, we return the last tagged child of the
* context node.
* - When the offset is before the context node, we return the first tagged child of the
* context node.
*
*/
static Node findNearestNodeAt(int offset, Node contextNode, Set> tags) {
Node node = (Node) ((InstrumentableNode) contextNode).materializeInstrumentableNodes(tags);
SourceSection section = node.getSourceSection();
int startIndex = section.getCharIndex();
int endIndex = getCharEndIndex(section);
if (startIndex <= offset && offset <= endIndex) {
Node ch;
while ((ch = findChildTaggedNode(node, offset, tags)) == null) {
node = node.getParent();
if (node == null) {
break;
}
}
return ch;
} else if (endIndex < offset) {
return findLastNode(node, tags);
} else { // offset < startIndex
return findFirstNode(node, tags);
}
}
private static void forEachInstrumentableChild(Node parent, NodeVisitor visitor, Set> tags) {
NodeUtil.forEachChild(parent, new NodeVisitor() {
private boolean keepVisiting = true;
@Override
public boolean visit(Node childNode) {
Node ch = childNode;
if (ch instanceof WrapperNode) {
ch = ((WrapperNode) ch).getDelegateNode();
}
if (ch instanceof InstrumentableNode && ((InstrumentableNode) ch).isInstrumentable()) {
ch = (Node) ((InstrumentableNode) ch).materializeInstrumentableNodes(tags);
} else {
// An unknown node, process its children on the same level.
NodeUtil.forEachChild(ch, this);
return keepVisiting;
}
return (keepVisiting = visitor.visit(ch));
}
});
}
/**
* Finds the nearest tagged {@link Node node}. See the algorithm description at
* {@link InstrumentableNode#findNearestNodeAt(int, Set)}.
*/
private static Node findChildTaggedNode(Node node, int offset, Set> tags) {
// Nodes with lower offset that we search for, inspected from the highest one.
SortedNodes lowerNodes = new SortedNodes();
// Nodes with higher offset that we search for, inspected from the smallest one.
SortedNodes higherNodes = new SortedNodes();
final Node[] foundNode = new Node[]{null};
forEachInstrumentableChild(node, new NodeVisitor() {
int highestLowerTaggedNodeStart = -1; // The nearest tagged node with lower offset
int highestLowerTaggedNodeEnd = -1;
int lowestHigherTaggedNodeStart = -1; // The nearest tagged node with higher offset
int lowestHigherTaggedNodeEnd = -1;
@Override
public boolean visit(Node ch) {
SourceSection ss = ch.getSourceSection();
if (ss == null || !ss.isAvailable()) {
return true;
}
boolean isTagged = isTaggedWith((InstrumentableNode) ch, tags);
int i1 = ss.getCharIndex();
int i2 = getCharEndIndex(ss);
if (isTagged && offset == i1) {
// We're at it
foundNode[0] = ch;
return false;
}
if (i1 <= offset && offset <= i2) {
// In an encapsulating source section
Node taggedNode = findChildTaggedNode(ch, offset, tags);
if (taggedNode != null) {
foundNode[0] = taggedNode;
return false;
}
if (isTagged) {
// If nothing in and is tagged, return it
foundNode[0] = ch;
return false;
}
}
if (offset < i1 && !(lowestHigherTaggedNodeStart <= i1 && i2 <= lowestHigherTaggedNodeEnd)) {
// We're after the offset
if (lowestHigherTaggedNodeStart == -1 || lowestHigherTaggedNodeStart > i1) {
higherNodes.add(ch, i1);
if (isTagged) {
lowestHigherTaggedNodeStart = i1;
lowestHigherTaggedNodeEnd = i2;
higherNodes.cutHigherThan(i1);
}
}
}
if (i2 < offset && !(highestLowerTaggedNodeStart <= i1 && i2 <= highestLowerTaggedNodeEnd)) {
// We're before the offset
if (highestLowerTaggedNodeStart == -1 || (highestLowerTaggedNodeStart < i1)) {
lowerNodes.add(ch, i1);
if (isTagged) {
highestLowerTaggedNodeStart = i1;
highestLowerTaggedNodeEnd = i2;
lowerNodes.cutLowerThan(i1);
}
}
}
return true;
}
}, tags);
if (foundNode[0] != null) {
return foundNode[0];
}
Node taggedNode = findChildTaggedNode(higherNodes.nodes, higherNodes.size, offset, tags, false);
if (taggedNode == null) {
taggedNode = findChildTaggedNode(lowerNodes.nodes, lowerNodes.size, offset, tags, true);
}
return taggedNode;
}
private static Node findChildTaggedNode(Node[] nodes, int size, int offset, Set> tags, boolean reverse) {
if (nodes == null) {
return null;
}
for (int i = (reverse ? size - 1 : 0); reverse ? i >= 0 : i < size; i = (reverse) ? i - 1 : i + 1) {
Node node = nodes[i];
if (isTaggedWith(node, tags)) {
return node;
}
Node taggedNode = findChildTaggedNode(node, offset, tags);
if (taggedNode != null) {
return taggedNode;
}
}
return null;
}
/** Get the last character index (inclusive). */
private static int getCharEndIndex(SourceSection ss) {
if (ss.getCharLength() > 0) {
return ss.getCharEndIndex() - 1;
} else {
return ss.getCharIndex();
}
}
private static Node findFirstNode(Node contextNode, Set> tags) {
Node[] first = new Node[]{null};
contextNode.accept(new NodeVisitor() {
@Override
public boolean visit(Node node) {
if (isTaggedWith(node, tags)) {
first[0] = node;
return false;
}
return true;
}
});
return first[0];
}
private static Node findLastNode(Node contextNode, Set> tags) {
if (isTaggedWith(contextNode, tags)) {
return contextNode;
}
List children = NodeUtil.findNodeChildren(contextNode);
for (int i = children.size() - 1; i >= 0; i--) {
Node ch = children.get(i);
if (ch instanceof WrapperNode) {
ch = ((WrapperNode) ch).getDelegateNode();
}
Node last = findLastNode(ch, tags);
if (last != null) {
return last;
}
}
return null;
}
private static boolean isTaggedWith(Node node, Set> tags) {
if (node instanceof InstrumentableNode && ((InstrumentableNode) node).isInstrumentable()) {
InstrumentableNode inode = ((InstrumentableNode) node).materializeInstrumentableNodes(tags);
return isTaggedWith(inode, tags);
}
return false;
}
private static boolean isTaggedWith(InstrumentableNode inode, Set> tags) {
for (Class tag : tags) {
if (inode.hasTag(tag)) {
return true;
}
}
return false;
}
private static final class SortedNodes {
private static final int DEFAULT_SIZE = 10;
private Node[] nodes = null;
int[] nodeOffsets = null;
int size = 0;
void add(Node node, int offset) {
if (nodes == null) {
nodes = new Node[DEFAULT_SIZE];
nodeOffsets = new int[DEFAULT_SIZE];
nodes[0] = node;
nodeOffsets[0] = offset;
size++;
} else {
ensureCapacity(size + 1);
if (nodeOffsets[size - 1] < offset) { // common case
nodes[size] = node;
nodeOffsets[size] = offset;
} else {
int index = Arrays.binarySearch(nodeOffsets, 0, size, offset);
if (index < 0) {
index = -index - 1;
}
System.arraycopy(nodes, index, nodes, index + 1, size - index);
nodes[index] = node;
System.arraycopy(nodeOffsets, index, nodeOffsets, index + 1, size - index);
nodeOffsets[index] = offset;
}
size++;
}
}
void ensureCapacity(int capacity) {
if (nodes.length < capacity) {
int newCapacity = capacity + (capacity >> 1);
if (newCapacity < capacity) {
newCapacity = capacity;
}
nodes = Arrays.copyOf(nodes, newCapacity);
nodeOffsets = Arrays.copyOf(nodeOffsets, newCapacity);
}
}
void cutHigherThan(int offset) {
int index = Arrays.binarySearch(nodeOffsets, 0, size, offset);
if (index < 0) {
index = -index - 1;
} else {
index++;
}
if (index < size) {
size = index;
}
}
void cutLowerThan(int offset) {
int index = Arrays.binarySearch(nodeOffsets, 0, size, offset);
if (index < 0) {
index = -index - 1;
}
if (index > 0) {
System.arraycopy(nodes, index, nodes, 0, size - index);
System.arraycopy(nodeOffsets, index, nodeOffsets, 0, size - index);
size -= index;
}
}
}
}