--- old/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/ir/Block.java 2020-04-15 18:47:32.000000000 +0530 +++ /dev/null 2020-04-15 18:47:32.000000000 +0530 @@ -1,540 +0,0 @@ -/* - * Copyright (c) 2010, 2017, 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.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 { - private static final long serialVersionUID = 1L; - - /** List of statements */ - protected final List statements; - - /** Symbol table - keys must be returned in the order they were put in. */ - protected final Map 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; - - /** - * Is this block tagged as breakable based on its contents - * (block having labelled break statement) - */ - public static final int IS_BREAKABLE = 1 << 8; - - /** - * 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 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 statements) { - this(token, finish, flags, statements.toArray(new Statement[0])); - } - - private Block(final Block block, final int finish, final List statements, final int flags, final Map 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 replacements) { - if (symbols.isEmpty()) { - return this; - } - final LinkedHashMap newSymbols = new LinkedHashMap<>(symbols); - for (final Map.Entry 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 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 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 catch block in a try 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 values = new ArrayList<>(symbols.values()); - - Collections.sort(values, new Comparator() { - @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) && !getFlag(IS_BREAKABLE); - } - - /** - * 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 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 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