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Truffle SL is an example language implemented using the Truffle API.
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
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* data (collectively the "Software"), free of charge and under any and all
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* (a) the Software, and
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* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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package com.oracle.truffle.sl.nodes.local;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.frame.FrameSlot;
import com.oracle.truffle.api.interop.ForeignAccess;
import com.oracle.truffle.api.interop.KeyInfo;
import com.oracle.truffle.api.interop.Message;
import com.oracle.truffle.api.interop.MessageResolution;
import com.oracle.truffle.api.interop.Resolve;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.api.interop.UnknownIdentifierException;
import com.oracle.truffle.api.interop.UnsupportedMessageException;
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.nodes.RootNode;
import com.oracle.truffle.sl.nodes.SLEvalRootNode;
import com.oracle.truffle.sl.nodes.SLStatementNode;
import com.oracle.truffle.sl.nodes.controlflow.SLBlockNode;
import com.oracle.truffle.sl.runtime.SLNull;
/**
* Simple language lexical scope. There can be a block scope, or function scope.
*/
public final class SLLexicalScope {
private final Node current;
private final SLBlockNode block;
private final SLBlockNode parentBlock;
private final RootNode root;
private SLLexicalScope parent;
private Map varSlots;
/**
* Create a new block SL lexical scope.
*
* @param current the current node
* @param block a nearest block enclosing the current node
* @param parentBlock a next parent block
*/
private SLLexicalScope(Node current, SLBlockNode block, SLBlockNode parentBlock) {
this.current = current;
this.block = block;
this.parentBlock = parentBlock;
this.root = null;
}
/**
* Create a new functional SL lexical scope.
*
* @param current the current node, or null when it would be above the block
* @param block a nearest block enclosing the current node
* @param root a functional root node for top-most block
*/
private SLLexicalScope(Node current, SLBlockNode block, RootNode root) {
this.current = current;
this.block = block;
this.parentBlock = null;
this.root = root;
}
@SuppressWarnings("all") // The parameter node should not be assigned
public static SLLexicalScope createScope(Node node) {
SLBlockNode block = getParentBlock(node);
if (block == null) {
// We're in the root.
block = findChildrenBlock(node);
if (block == null) {
// Corrupted SL AST, no block was found
assert node.getRootNode() instanceof SLEvalRootNode : "Corrupted SL AST under " + node;
return new SLLexicalScope(null, null, (SLBlockNode) null);
}
node = null; // node is above the block
}
// Test if there is a parent block. If not, we're in the root scope.
SLBlockNode parentBlock = getParentBlock(block);
if (parentBlock == null) {
return new SLLexicalScope(node, block, block.getRootNode());
} else {
return new SLLexicalScope(node, block, parentBlock);
}
}
private static SLBlockNode getParentBlock(Node node) {
SLBlockNode block;
Node parent = node.getParent();
// Find a nearest block node.
while (parent != null && !(parent instanceof SLBlockNode)) {
parent = parent.getParent();
}
if (parent != null) {
block = (SLBlockNode) parent;
} else {
block = null;
}
return block;
}
private static SLBlockNode findChildrenBlock(Node node) {
SLBlockNode[] blockPtr = new SLBlockNode[1];
node.accept(new NodeVisitor() {
@Override
public boolean visit(Node n) {
if (n instanceof SLBlockNode) {
blockPtr[0] = (SLBlockNode) n;
return false;
} else {
return true;
}
}
});
return blockPtr[0];
}
public SLLexicalScope findParent() {
if (parentBlock == null) {
// This was a root scope.
return null;
}
if (parent == null) {
Node node = block;
SLBlockNode newBlock = parentBlock;
// Test if there is a next parent block. If not, we're in the root scope.
SLBlockNode newParentBlock = getParentBlock(newBlock);
if (newParentBlock == null) {
parent = new SLLexicalScope(node, newBlock, newBlock.getRootNode());
} else {
parent = new SLLexicalScope(node, newBlock, newParentBlock);
}
}
return parent;
}
/**
* @return the function name for function scope, "block" otherwise.
*/
public String getName() {
if (root != null) {
return root.getName();
} else {
return "block";
}
}
/**
* @return the node representing the scope, the block node for block scopes and the
* {@link RootNode} for functional scope.
*/
public Node getNode() {
if (root != null) {
return root;
} else {
return block;
}
}
public Object getVariables(Frame frame) {
Map vars = getVars();
Object[] args = null;
// Use arguments when the current node is above the block
if (current == null) {
args = (frame != null) ? frame.getArguments() : null;
}
return new VariablesMapObject(vars, args, frame);
}
public Object getArguments(Frame frame) {
if (root == null) {
// No arguments for block scope
return null;
}
// The slots give us names of the arguments:
Map argSlots = collectArgs(block);
// The frame's arguments array give us the argument values:
Object[] args = (frame != null) ? frame.getArguments() : null;
// Create a TruffleObject having the arguments as properties:
return new VariablesMapObject(argSlots, args, frame);
}
private Map getVars() {
if (varSlots == null) {
if (current != null) {
varSlots = collectVars(block, current);
} else if (block != null) {
// Provide the arguments only when the current node is above the block
varSlots = collectArgs(block);
} else {
varSlots = Collections.emptyMap();
}
}
return varSlots;
}
private boolean hasParentVar(String name) {
SLLexicalScope p = this;
while ((p = p.findParent()) != null) {
if (p.getVars().containsKey(name)) {
return true;
}
}
return false;
}
private Map collectVars(Node varsBlock, Node currentNode) {
// Variables are slot-based.
// To collect declared variables, traverse the block's AST and find slots associated
// with SLWriteLocalVariableNode. The traversal stops when we hit the current node.
Map slots = new LinkedHashMap<>(4);
NodeUtil.forEachChild(varsBlock, new NodeVisitor() {
@Override
public boolean visit(Node node) {
if (node == currentNode) {
return false;
}
// Do not enter any nested blocks.
if (!(node instanceof SLBlockNode)) {
boolean all = NodeUtil.forEachChild(node, this);
if (!all) {
return false;
}
}
// Write to a variable is a declaration unless it exists already in a parent scope.
if (node instanceof SLWriteLocalVariableNode) {
SLWriteLocalVariableNode wn = (SLWriteLocalVariableNode) node;
String name = Objects.toString(wn.getSlot().getIdentifier());
if (!hasParentVar(name)) {
slots.put(name, wn.getSlot());
}
}
return true;
}
});
return slots;
}
private static Map collectArgs(Node block) {
// Arguments are pushed to frame slots at the beginning of the function block.
// To collect argument slots, search for SLReadArgumentNode inside of
// SLWriteLocalVariableNode.
Map args = new LinkedHashMap<>(4);
NodeUtil.forEachChild(block, new NodeVisitor() {
private SLWriteLocalVariableNode wn; // The current write node containing a slot
@Override
public boolean visit(Node node) {
// When there is a write node, search for SLReadArgumentNode among its children:
if (node instanceof SLWriteLocalVariableNode) {
wn = (SLWriteLocalVariableNode) node;
boolean all = NodeUtil.forEachChild(node, this);
wn = null;
return all;
} else if (wn != null && (node instanceof SLReadArgumentNode)) {
FrameSlot slot = wn.getSlot();
String name = Objects.toString(slot.getIdentifier());
assert !args.containsKey(name) : name + " argument exists already.";
args.put(name, slot);
return true;
} else if (wn == null && (node instanceof SLStatementNode)) {
// A different SL node - we're done.
return false;
} else {
return NodeUtil.forEachChild(node, this);
}
}
});
return args;
}
static final class VariablesMapObject implements TruffleObject {
final Map slots;
final Object[] args;
final Frame frame;
private VariablesMapObject(Map slots, Object[] args, Frame frame) {
this.slots = slots;
this.args = args;
this.frame = frame;
}
@Override
public ForeignAccess getForeignAccess() {
return VariablesMapMessageResolutionForeign.ACCESS;
}
public static boolean isInstance(TruffleObject obj) {
return obj instanceof VariablesMapObject;
}
@MessageResolution(receiverType = VariablesMapObject.class)
static final class VariablesMapMessageResolution {
@Resolve(message = "HAS_KEYS")
abstract static class VarsMapHasKeysNode extends Node {
public Object access(VariablesMapObject varMap) {
assert varMap != null;
return true;
}
}
@Resolve(message = "KEYS")
abstract static class VarsMapKeysNode extends Node {
@TruffleBoundary
public Object access(VariablesMapObject varMap) {
return new VariableNamesObject(varMap.slots.keySet());
}
}
@Resolve(message = "KEY_INFO")
abstract static class KeyInfoNode extends Node {
@TruffleBoundary
public int access(VariablesMapObject varMap, String name) {
if (varMap.frame == null) {
return KeyInfo.READABLE;
}
FrameSlot slot = varMap.slots.get(name);
if (slot != null) {
return KeyInfo.READABLE | KeyInfo.MODIFIABLE;
}
return KeyInfo.NONE;
}
}
@Resolve(message = "READ")
abstract static class VarsMapReadNode extends Node {
@TruffleBoundary
public Object access(VariablesMapObject varMap, String name) {
if (varMap.frame == null) {
return SLNull.SINGLETON;
}
FrameSlot slot = varMap.slots.get(name);
if (slot == null) {
throw UnknownIdentifierException.raise(name);
} else {
Object value;
if (varMap.args != null && varMap.args.length > slot.getIndex()) {
value = varMap.args[slot.getIndex()];
} else {
value = varMap.frame.getValue(slot);
}
return value;
}
}
}
@Resolve(message = "WRITE")
abstract static class VarsMapWriteNode extends Node {
@TruffleBoundary
public Object access(VariablesMapObject varMap, String name, Object value) {
if (varMap.frame == null) {
throw UnsupportedMessageException.raise(Message.WRITE);
}
FrameSlot slot = varMap.slots.get(name);
if (slot == null) {
throw UnknownIdentifierException.raise(name);
} else {
if (varMap.args != null && varMap.args.length > slot.getIndex()) {
varMap.args[slot.getIndex()] = value;
} else {
varMap.frame.setObject(slot, value);
}
return value;
}
}
}
}
}
static final class VariableNamesObject implements TruffleObject {
final List names;
private VariableNamesObject(Set names) {
this.names = new ArrayList<>(names);
}
@Override
public ForeignAccess getForeignAccess() {
return VariableNamesMessageResolutionForeign.ACCESS;
}
public static boolean isInstance(TruffleObject obj) {
return obj instanceof VariableNamesObject;
}
@MessageResolution(receiverType = VariableNamesObject.class)
static final class VariableNamesMessageResolution {
@Resolve(message = "HAS_SIZE")
abstract static class VarNamesHasSizeNode extends Node {
@SuppressWarnings("unused")
public Object access(VariableNamesObject varNames) {
return true;
}
}
@Resolve(message = "GET_SIZE")
abstract static class VarNamesGetSizeNode extends Node {
public Object access(VariableNamesObject varNames) {
return varNames.names.size();
}
}
@Resolve(message = "READ")
abstract static class VarNamesReadNode extends Node {
@TruffleBoundary
public Object access(VariableNamesObject varNames, int index) {
try {
return varNames.names.get(index);
} catch (IndexOutOfBoundsException ioob) {
throw UnknownIdentifierException.raise(Integer.toString(index));
}
}
}
}
}
}
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