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*
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package jdk.nashorn.internal.ir;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import jdk.nashorn.internal.codegen.Label;
import jdk.nashorn.internal.ir.annotations.Immutable;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;
/**
* IR representation for a list of statements.
*/
@Immutable
public class Block extends Node implements BreakableNode, Terminal, Flags<Block> {
private static final long serialVersionUID = 1L;
/** List of statements */
protected final List<Statement> statements;
/** Symbol table - keys must be returned in the order they were put in. */
protected final Map<String, Symbol> symbols;
/** Entry label. */
private final Label entryLabel;
/** Break label. */
private final Label breakLabel;
/** Does the block/function need a new scope? Is this synthetic? */
protected final int flags;
/**
* @see JoinPredecessor
*/
private final LocalVariableConversion conversion;
/** Flag indicating that this block needs scope */
public static final int NEEDS_SCOPE = 1 << 0;
/**
* Is this block tagged as terminal based on its contents
* (usually the last statement)
*/
public static final int IS_TERMINAL = 1 << 2;
/**
* Is this block the eager global scope - i.e. the original program. This isn't true for the
* outermost level of recompiles
*/
public static final int IS_GLOBAL_SCOPE = 1 << 3;
/**
* Is this block a synthetic one introduced by Parser?
*/
public static final int IS_SYNTHETIC = 1 << 4;
/**
* Is this the function body block? May not be the first, if parameter list contains expressions.
*/
public static final int IS_BODY = 1 << 5;
/**
* Is this the parameter initialization block? If present, must be the first block, immediately wrapping the function body block.
*/
public static final int IS_PARAMETER_BLOCK = 1 << 6;
/**
* Marks the variable declaration block for case clauses of a switch statement.
*/
public static final int IS_SWITCH_BLOCK = 1 << 7;
/**
* Constructor
*
* @param token The first token of the block
* @param finish The index of the last character
* @param flags The flags of the block
* @param statements All statements in the block
*/
public Block(final long token, final int finish, final int flags, final Statement... statements) {
super(token, finish);
this.statements = Arrays.asList(statements);
this.symbols = new LinkedHashMap<>();
this.entryLabel = new Label("block_entry");
this.breakLabel = new Label("block_break");
final int len = statements.length;
final int terminalFlags = len > 0 && statements[len - 1].hasTerminalFlags() ? IS_TERMINAL : 0;
this.flags = terminalFlags | flags;
this.conversion = null;
}
/**
* Constructs a new block
*
* @param token The first token of the block
* @param finish The index of the last character
* @param statements All statements in the block
*/
public Block(final long token, final int finish, final Statement...statements){
this(token, finish, IS_SYNTHETIC, statements);
}
/**
* Constructs a new block
*
* @param token The first token of the block
* @param finish The index of the last character
* @param statements All statements in the block
*/
public Block(final long token, final int finish, final List<Statement> statements){
this(token, finish, IS_SYNTHETIC, statements);
}
/**
* Constructor
*
* @param token The first token of the block
* @param finish The index of the last character
* @param flags The flags of the block
* @param statements All statements in the block
*/
public Block(final long token, final int finish, final int flags, final List<Statement> statements) {
this(token, finish, flags, statements.toArray(new Statement[0]));
}
private Block(final Block block, final int finish, final List<Statement> statements, final int flags, final Map<String, Symbol> symbols, final LocalVariableConversion conversion) {
super(block, finish);
this.statements = statements;
this.flags = flags;
this.symbols = new LinkedHashMap<>(symbols); //todo - symbols have no dependencies on any IR node and can as far as we understand it be shallow copied now
this.entryLabel = new Label(block.entryLabel);
this.breakLabel = new Label(block.breakLabel);
this.conversion = conversion;
}
/**
* Is this block the outermost eager global scope - i.e. the primordial program?
* Used for global anchor point for scope depth computation for recompilation code
* @return true if outermost eager global scope
*/
public boolean isGlobalScope() {
return getFlag(IS_GLOBAL_SCOPE);
}
/**
* Returns true if this block defines any symbols.
* @return true if this block defines any symbols.
*/
public boolean hasSymbols() {
return !symbols.isEmpty();
}
/**
* Replaces symbols defined in this block with different symbols. Used to ensure symbol tables are
* immutable upon construction and have copy-on-write semantics. Note that this method only replaces the
* symbols in the symbol table, it does not act on any contained AST nodes that might reference the symbols.
* Those should be updated separately as this method is meant to be used as part of such an update pass.
* @param lc the current lexical context
* @param replacements the map of symbol replacements
* @return a new block with replaced symbols, or this block if none of the replacements modified the symbol
* table.
*/
public Block replaceSymbols(final LexicalContext lc, final Map<Symbol, Symbol> replacements) {
if (symbols.isEmpty()) {
return this;
}
final LinkedHashMap<String, Symbol> newSymbols = new LinkedHashMap<>(symbols);
for (final Map.Entry<String, Symbol> entry: newSymbols.entrySet()) {
final Symbol newSymbol = replacements.get(entry.getValue());
assert newSymbol != null : "Missing replacement for " + entry.getKey();
entry.setValue(newSymbol);
}
return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, newSymbols, conversion));
}
/**
* Returns a copy of this block with a shallow copy of the symbol table.
* @return a copy of this block with a shallow copy of the symbol table.
*/
public Block copyWithNewSymbols() {
return new Block(this, finish, statements, flags, new LinkedHashMap<>(symbols), conversion);
}
@Override
public Node ensureUniqueLabels(final LexicalContext lc) {
return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
}
/**
* Assist in IR navigation.
*
* @param visitor IR navigating visitor.
* @return new or same node
*/
@Override
public Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor) {
if (visitor.enterBlock(this)) {
return visitor.leaveBlock(setStatements(lc, Node.accept(visitor, statements)));
}
return this;
}
/**
* Get a copy of the list for all the symbols defined in this block
* @return symbol iterator
*/
public List<Symbol> getSymbols() {
return symbols.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(new ArrayList<>(symbols.values()));
}
/**
* Retrieves an existing symbol defined in the current block.
* @param name the name of the symbol
* @return an existing symbol with the specified name defined in the current block, or null if this block doesn't
* define a symbol with this name.T
*/
public Symbol getExistingSymbol(final String name) {
return symbols.get(name);
}
/**
* Test if this block represents a <tt>catch</tt> block in a <tt>try</tt> statement.
* This is used by the Splitter as catch blocks are not be subject to splitting.
*
* @return true if this block represents a catch block in a try statement.
*/
public boolean isCatchBlock() {
return statements.size() == 1 && statements.get(0) instanceof CatchNode;
}
@Override
public void toString(final StringBuilder sb, final boolean printType) {
for (final Node statement : statements) {
statement.toString(sb, printType);
sb.append(';');
}
}
/**
* Print symbols in block in alphabetical order, sorted on name
* Used for debugging, see the --print-symbols flag
*
* @param stream print writer to output symbols to
*
* @return true if symbols were found
*/
public boolean printSymbols(final PrintWriter stream) {
final List<Symbol> values = new ArrayList<>(symbols.values());
Collections.sort(values, new Comparator<Symbol>() {
@Override
public int compare(final Symbol s0, final Symbol s1) {
return s0.getName().compareTo(s1.getName());
}
});
for (final Symbol symbol : values) {
symbol.print(stream);
}
return !values.isEmpty();
}
/**
* Tag block as terminal or non terminal
* @param lc lexical context
* @param isTerminal is block terminal
* @return same block, or new if flag changed
*/
public Block setIsTerminal(final LexicalContext lc, final boolean isTerminal) {
return isTerminal ? setFlag(lc, IS_TERMINAL) : clearFlag(lc, IS_TERMINAL);
}
@Override
public int getFlags() {
return flags;
}
/**
* Is this a terminal block, i.e. does it end control flow like ending with a throw or return?
*
* @return true if this node statement is terminal
*/
@Override
public boolean isTerminal() {
return getFlag(IS_TERMINAL);
}
/**
* Get the entry label for this block
* @return the entry label
*/
public Label getEntryLabel() {
return entryLabel;
}
@Override
public Label getBreakLabel() {
return breakLabel;
}
@Override
public Block setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
if(this.conversion == conversion) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
}
@Override
public LocalVariableConversion getLocalVariableConversion() {
return conversion;
}
/**
* Get the list of statements in this block
*
* @return a list of statements
*/
public List<Statement> getStatements() {
return Collections.unmodifiableList(statements);
}
/**
* Returns the number of statements in the block.
* @return the number of statements in the block.
*/
public int getStatementCount() {
return statements.size();
}
/**
* Returns the line number of the first statement in the block.
* @return the line number of the first statement in the block, or -1 if the block has no statements.
*/
public int getFirstStatementLineNumber() {
if(statements == null || statements.isEmpty()) {
return -1;
}
return statements.get(0).getLineNumber();
}
/**
* Returns the last statement in the block.
* @return the last statement in the block, or null if the block has no statements.
*/
public Statement getLastStatement() {
return statements.isEmpty() ? null : statements.get(statements.size() - 1);
}
/**
* Reset the statement list for this block
*
* @param lc lexical context
* @param statements new statement list
* @return new block if statements changed, identity of statements == block.statements
*/
public Block setStatements(final LexicalContext lc, final List<Statement> statements) {
if (this.statements == statements) {
return this;
}
int lastFinish = 0;
if (!statements.isEmpty()) {
lastFinish = statements.get(statements.size() - 1).getFinish();
}
return Node.replaceInLexicalContext(lc, this, new Block(this, Math.max(finish, lastFinish), statements, flags, symbols, conversion));
}
/**
* Add or overwrite an existing symbol in the block
*
* @param symbol symbol
*/
public void putSymbol(final Symbol symbol) {
symbols.put(symbol.getName(), symbol);
}
/**
* Check whether scope is necessary for this Block
*
* @return true if this function needs a scope
*/
public boolean needsScope() {
return (flags & NEEDS_SCOPE) == NEEDS_SCOPE;
}
/**
* Check whether this block is synthetic or not.
*
* @return true if this is a synthetic block
*/
public boolean isSynthetic() {
return (flags & IS_SYNTHETIC) == IS_SYNTHETIC;
}
@Override
public Block setFlags(final LexicalContext lc, final int flags) {
if (this.flags == flags) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
}
@Override
public Block clearFlag(final LexicalContext lc, final int flag) {
return setFlags(lc, flags & ~flag);
}
@Override
public Block setFlag(final LexicalContext lc, final int flag) {
return setFlags(lc, flags | flag);
}
@Override
public boolean getFlag(final int flag) {
return (flags & flag) == flag;
}
/**
* Set the needs scope flag.
* @param lc lexicalContext
* @return new block if state changed, otherwise this
*/
public Block setNeedsScope(final LexicalContext lc) {
if (needsScope()) {
return this;
}
return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags | NEEDS_SCOPE, symbols, conversion));
}
/**
* Computationally determine the next slot for this block,
* indexed from 0. Use this as a relative base when computing
* frames
* @return next slot
*/
public int nextSlot() {
int next = 0;
for (final Symbol symbol : getSymbols()) {
if (symbol.hasSlot()) {
next += symbol.slotCount();
}
}
return next;
}
/**
* Determine whether this block needs to provide its scope object creator for use by its child nodes.
* This is only necessary for synthetic parent blocks of for-in loops with lexical declarations.
*
* @see ForNode#needsScopeCreator()
* @return true if child nodes need access to this block's scope creator
*/
public boolean providesScopeCreator() {
return needsScope() && isSynthetic()
&& (getLastStatement() instanceof ForNode)
&& ((ForNode) getLastStatement()).needsScopeCreator();
}
@Override
public boolean isBreakableWithoutLabel() {
return false;
}
@Override
public List<Label> getLabels() {
return Collections.unmodifiableList(Arrays.asList(entryLabel, breakLabel));
}
@Override
public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
return Acceptor.accept(this, visitor);
}
/**
* Checks if this is a function body.
*
* @return true if the function body flag is set
*/
public boolean isFunctionBody() {
return getFlag(IS_BODY);
}
/**
* Checks if this is a parameter block.
*
* @return true if the parameter block flag is set
*/
public boolean isParameterBlock() {
return getFlag(IS_PARAMETER_BLOCK);
}
/**
* Checks whether this is a switch block.
*
* @return true if this is a switch block
*/
public boolean isSwitchBlock() {
return getFlag(IS_SWITCH_BLOCK);
}
}