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+/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Rhino code, released
+ * May 6, 1999.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1997-1999
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ * Norris Boyd
+ * Roshan James
+ * Roger Lawrence
+ * Mike McCabe
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License Version 2 or later (the "GPL"), in which
+ * case the provisions of the GPL are applicable instead of those above. If
+ * you wish to allow use of your version of this file only under the terms of
+ * the GPL and not to allow others to use your version of this file under the
+ * MPL, indicate your decision by deleting the provisions above and replacing
+ * them with the notice and other provisions required by the GPL. If you do
+ * not delete the provisions above, a recipient may use your version of this
+ * file under either the MPL or the GPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+package org.mozilla.javascript;
+
+import java.util.Map;
+import java.util.LinkedHashMap;
+import java.util.Iterator;
+import java.util.Collections;
+
+/**
+ * This class implements the root of the intermediate representation.
+ *
+ * @author Norris Boyd
+ * @author Mike McCabe
+ */
+
+public class Node
+{
+ public static final int
+ FUNCTION_PROP = 1,
+ LOCAL_PROP = 2,
+ LOCAL_BLOCK_PROP = 3,
+ REGEXP_PROP = 4,
+ CASEARRAY_PROP = 5,
+ /*
+ the following properties are defined and manipulated by the
+ optimizer -
+ TARGETBLOCK_PROP - the block referenced by a branch node
+ VARIABLE_PROP - the variable referenced by a BIND or NAME node
+ ISNUMBER_PROP - this node generates code on Number children and
+ delivers a Number result (as opposed to Objects)
+ DIRECTCALL_PROP - this call node should emit code to test the function
+ object against the known class and call diret if it
+ matches.
+ */
+
+ TARGETBLOCK_PROP = 6,
+ VARIABLE_PROP = 7,
+ ISNUMBER_PROP = 8,
+ DIRECTCALL_PROP = 9,
+ SPECIALCALL_PROP = 10,
+ SKIP_INDEXES_PROP = 11, // array of skipped indexes of array literal
+ OBJECT_IDS_PROP = 12, // array of properties for object literal
+ INCRDECR_PROP = 13, // pre or post type of increment/decerement
+ CATCH_SCOPE_PROP = 14, // index of catch scope block in catch
+ LABEL_ID_PROP = 15, // label id: code generation uses it
+ MEMBER_TYPE_PROP = 16, // type of element access operation
+ NAME_PROP = 17, // property name
+ CONTROL_BLOCK_PROP = 18, // flags a control block that can drop off
+ PARENTHESIZED_PROP = 19, // expression is parenthesized
+ GENERATOR_END_PROP = 20,
+ DESTRUCTURING_ARRAY_LENGTH = 21,
+ DESTRUCTURING_NAMES= 22,
+ LAST_PROP = 22;
+
+ // values of ISNUMBER_PROP to specify
+ // which of the children are Number types
+ public static final int
+ BOTH = 0,
+ LEFT = 1,
+ RIGHT = 2;
+
+ public static final int // values for SPECIALCALL_PROP
+ NON_SPECIALCALL = 0,
+ SPECIALCALL_EVAL = 1,
+ SPECIALCALL_WITH = 2;
+
+ public static final int // flags for INCRDECR_PROP
+ DECR_FLAG = 0x1,
+ POST_FLAG = 0x2;
+
+ public static final int // flags for MEMBER_TYPE_PROP
+ PROPERTY_FLAG = 0x1, // property access: element is valid name
+ ATTRIBUTE_FLAG = 0x2, // x.@y or x..@y
+ DESCENDANTS_FLAG = 0x4; // x..y or x..@i
+
+ private static class NumberNode extends Node
+ {
+ NumberNode(double number)
+ {
+ super(Token.NUMBER);
+ this.number = number;
+ }
+
+ double number;
+ }
+
+ private static class StringNode extends Node
+ {
+ StringNode(int type, String str) {
+ super(type);
+ this.str = str;
+ }
+
+ String str;
+ Node.Scope scope;
+ }
+
+ public static class Jump extends Node
+ {
+ public Jump(int type)
+ {
+ super(type);
+ }
+
+ Jump(int type, int lineno)
+ {
+ super(type, lineno);
+ }
+
+ Jump(int type, Node child)
+ {
+ super(type, child);
+ }
+
+ Jump(int type, Node child, int lineno)
+ {
+ super(type, child, lineno);
+ }
+
+ public final Jump getJumpStatement()
+ {
+ if (!(type == Token.BREAK || type == Token.CONTINUE)) Kit.codeBug();
+ return jumpNode;
+ }
+
+ public final void setJumpStatement(Jump jumpStatement)
+ {
+ if (!(type == Token.BREAK || type == Token.CONTINUE)) Kit.codeBug();
+ if (jumpStatement == null) Kit.codeBug();
+ if (this.jumpNode != null) Kit.codeBug(); //only once
+ this.jumpNode = jumpStatement;
+ }
+
+ public final Node getDefault()
+ {
+ if (!(type == Token.SWITCH)) Kit.codeBug();
+ return target2;
+ }
+
+ public final void setDefault(Node defaultTarget)
+ {
+ if (!(type == Token.SWITCH)) Kit.codeBug();
+ if (defaultTarget.type != Token.TARGET) Kit.codeBug();
+ if (target2 != null) Kit.codeBug(); //only once
+ target2 = defaultTarget;
+ }
+
+ public final Node getFinally()
+ {
+ if (!(type == Token.TRY)) Kit.codeBug();
+ return target2;
+ }
+
+ public final void setFinally(Node finallyTarget)
+ {
+ if (!(type == Token.TRY)) Kit.codeBug();
+ if (finallyTarget.type != Token.TARGET) Kit.codeBug();
+ if (target2 != null) Kit.codeBug(); //only once
+ target2 = finallyTarget;
+ }
+
+ public final Jump getLoop()
+ {
+ if (!(type == Token.LABEL)) Kit.codeBug();
+ return jumpNode;
+ }
+
+ public final void setLoop(Jump loop)
+ {
+ if (!(type == Token.LABEL)) Kit.codeBug();
+ if (loop == null) Kit.codeBug();
+ if (jumpNode != null) Kit.codeBug(); //only once
+ jumpNode = loop;
+ }
+
+ public final Node getContinue()
+ {
+ if (type != Token.LOOP) Kit.codeBug();
+ return target2;
+ }
+
+ public final void setContinue(Node continueTarget)
+ {
+ if (type != Token.LOOP) Kit.codeBug();
+ if (continueTarget.type != Token.TARGET) Kit.codeBug();
+ if (target2 != null) Kit.codeBug(); //only once
+ target2 = continueTarget;
+ }
+
+ public Node target;
+ private Node target2;
+ private Jump jumpNode;
+ }
+
+ static class Symbol {
+ Symbol(int declType, String name) {
+ this.declType = declType;
+ this.name = name;
+ this.index = -1;
+ }
+ /**
+ * One of Token.FUNCTION, Token.LP (for parameters), Token.VAR,
+ * Token.LET, or Token.CONST
+ */
+ int declType;
+ int index;
+ String name;
+ Node.Scope containingTable;
+ }
+
+ static class Scope extends Jump {
+ public Scope(int nodeType) {
+ super(nodeType);
+ }
+
+ public Scope(int nodeType, int lineno) {
+ super(nodeType, lineno);
+ }
+
+ public Scope(int nodeType, Node n, int lineno) {
+ super(nodeType, n, lineno);
+ }
+
+ /*
+ * Creates a new scope node, moving symbol table information
+ * from "scope" to the new node, and making "scope" a nested
+ * scope contained by the new node.
+ * Useful for injecting a new scope in a scope chain.
+ */
+ public static Scope splitScope(Scope scope) {
+ Scope result = new Scope(scope.getType());
+ result.symbolTable = scope.symbolTable;
+ scope.symbolTable = null;
+ result.parent = scope.parent;
+ scope.parent = result;
+ result.top = scope.top;
+ return result;
+ }
+
+ public static void joinScopes(Scope source, Scope dest) {
+ source.ensureSymbolTable();
+ dest.ensureSymbolTable();
+ if (!Collections.disjoint(source.symbolTable.keySet(),
+ dest.symbolTable.keySet()))
+ {
+ throw Kit.codeBug();
+ }
+ dest.symbolTable.putAll(source.symbolTable);
+ }
+
+ public void setParent(Scope parent) {
+ this.parent = parent;
+ this.top = parent == null ? (ScriptOrFnNode)this : parent.top;
+ }
+
+ public Scope getParentScope() {
+ return parent;
+ }
+
+ public Scope getDefiningScope(String name) {
+ for (Scope sn=this; sn != null; sn = sn.parent) {
+ if (sn.symbolTable == null)
+ continue;
+ if (sn.symbolTable.containsKey(name))
+ return sn;
+ }
+ return null;
+ }
+
+ public Symbol getSymbol(String name) {
+ return symbolTable == null ? null : symbolTable.get(name);
+ }
+
+ public void putSymbol(String name, Symbol symbol) {
+ ensureSymbolTable();
+ symbolTable.put(name, symbol);
+ symbol.containingTable = this;
+ top.addSymbol(symbol);
+ }
+
+ public Map<String,Symbol> getSymbolTable() {
+ return symbolTable;
+ }
+
+ private void ensureSymbolTable() {
+ if (symbolTable == null) {
+ symbolTable = new LinkedHashMap<String,Symbol>(5);
+ }
+ }
+
+ // Use LinkedHashMap so that the iteration order is the insertion order
+ protected LinkedHashMap<String,Symbol> symbolTable;
+ private Scope parent;
+ private ScriptOrFnNode top;
+ }
+
+ private static class PropListItem
+ {
+ PropListItem next;
+ int type;
+ int intValue;
+ Object objectValue;
+ }
+
+
+ public Node(int nodeType) {
+ type = nodeType;
+ }
+
+ public Node(int nodeType, Node child) {
+ type = nodeType;
+ first = last = child;
+ child.next = null;
+ }
+
+ public Node(int nodeType, Node left, Node right) {
+ type = nodeType;
+ first = left;
+ last = right;
+ left.next = right;
+ right.next = null;
+ }
+
+ public Node(int nodeType, Node left, Node mid, Node right) {
+ type = nodeType;
+ first = left;
+ last = right;
+ left.next = mid;
+ mid.next = right;
+ right.next = null;
+ }
+
+ public Node(int nodeType, int line) {
+ type = nodeType;
+ lineno = line;
+ }
+
+ public Node(int nodeType, Node child, int line) {
+ this(nodeType, child);
+ lineno = line;
+ }
+
+ public Node(int nodeType, Node left, Node right, int line) {
+ this(nodeType, left, right);
+ lineno = line;
+ }
+
+ public Node(int nodeType, Node left, Node mid, Node right, int line) {
+ this(nodeType, left, mid, right);
+ lineno = line;
+ }
+
+ public static Node newNumber(double number) {
+ return new NumberNode(number);
+ }
+
+ public static Node newString(String str) {
+ return new StringNode(Token.STRING, str);
+ }
+
+ public static Node newString(int type, String str) {
+ return new StringNode(type, str);
+ }
+
+ public int getType() {
+ return type;
+ }
+
+ public void setType(int type) {
+ this.type = type;
+ }
+
+ public boolean hasChildren() {
+ return first != null;
+ }
+
+ public Node getFirstChild() {
+ return first;
+ }
+
+ public Node getLastChild() {
+ return last;
+ }
+
+ public Node getNext() {
+ return next;
+ }
+
+ public Node getChildBefore(Node child) {
+ if (child == first)
+ return null;
+ Node n = first;
+ while (n.next != child) {
+ n = n.next;
+ if (n == null)
+ throw new RuntimeException("node is not a child");
+ }
+ return n;
+ }
+
+ public Node getLastSibling() {
+ Node n = this;
+ while (n.next != null) {
+ n = n.next;
+ }
+ return n;
+ }
+
+ public void addChildToFront(Node child) {
+ child.next = first;
+ first = child;
+ if (last == null) {
+ last = child;
+ }
+ }
+
+ public void addChildToBack(Node child) {
+ child.next = null;
+ if (last == null) {
+ first = last = child;
+ return;
+ }
+ last.next = child;
+ last = child;
+ }
+
+ public void addChildrenToFront(Node children) {
+ Node lastSib = children.getLastSibling();
+ lastSib.next = first;
+ first = children;
+ if (last == null) {
+ last = lastSib;
+ }
+ }
+
+ public void addChildrenToBack(Node children) {
+ if (last != null) {
+ last.next = children;
+ }
+ last = children.getLastSibling();
+ if (first == null) {
+ first = children;
+ }
+ }
+
+ /**
+ * Add 'child' before 'node'.
+ */
+ public void addChildBefore(Node newChild, Node node) {
+ if (newChild.next != null)
+ throw new RuntimeException(
+ "newChild had siblings in addChildBefore");
+ if (first == node) {
+ newChild.next = first;
+ first = newChild;
+ return;
+ }
+ Node prev = getChildBefore(node);
+ addChildAfter(newChild, prev);
+ }
+
+ /**
+ * Add 'child' after 'node'.
+ */
+ public void addChildAfter(Node newChild, Node node) {
+ if (newChild.next != null)
+ throw new RuntimeException(
+ "newChild had siblings in addChildAfter");
+ newChild.next = node.next;
+ node.next = newChild;
+ if (last == node)
+ last = newChild;
+ }
+
+ public void removeChild(Node child) {
+ Node prev = getChildBefore(child);
+ if (prev == null)
+ first = first.next;
+ else
+ prev.next = child.next;
+ if (child == last) last = prev;
+ child.next = null;
+ }
+
+ public void replaceChild(Node child, Node newChild) {
+ newChild.next = child.next;
+ if (child == first) {
+ first = newChild;
+ } else {
+ Node prev = getChildBefore(child);
+ prev.next = newChild;
+ }
+ if (child == last)
+ last = newChild;
+ child.next = null;
+ }
+
+ public void replaceChildAfter(Node prevChild, Node newChild) {
+ Node child = prevChild.next;
+ newChild.next = child.next;
+ prevChild.next = newChild;
+ if (child == last)
+ last = newChild;
+ child.next = null;
+ }
+
+ private static final String propToString(int propType)
+ {
+ if (Token.printTrees) {
+ // If Context.printTrees is false, the compiler
+ // can remove all these strings.
+ switch (propType) {
+ case FUNCTION_PROP: return "function";
+ case LOCAL_PROP: return "local";
+ case LOCAL_BLOCK_PROP: return "local_block";
+ case REGEXP_PROP: return "regexp";
+ case CASEARRAY_PROP: return "casearray";
+
+ case TARGETBLOCK_PROP: return "targetblock";
+ case VARIABLE_PROP: return "variable";
+ case ISNUMBER_PROP: return "isnumber";
+ case DIRECTCALL_PROP: return "directcall";
+
+ case SPECIALCALL_PROP: return "specialcall";
+ case SKIP_INDEXES_PROP: return "skip_indexes";
+ case OBJECT_IDS_PROP: return "object_ids_prop";
+ case INCRDECR_PROP: return "incrdecr_prop";
+ case CATCH_SCOPE_PROP: return "catch_scope_prop";
+ case LABEL_ID_PROP: return "label_id_prop";
+ case MEMBER_TYPE_PROP: return "member_type_prop";
+ case NAME_PROP: return "name_prop";
+ case CONTROL_BLOCK_PROP: return "control_block_prop";
+ case PARENTHESIZED_PROP: return "parenthesized_prop";
+ case GENERATOR_END_PROP: return "generator_end";
+ case DESTRUCTURING_ARRAY_LENGTH:
+ return "destructuring_array_length";
+ case DESTRUCTURING_NAMES:return "destructuring_names";
+
+ default: Kit.codeBug();
+ }
+ }
+ return null;
+ }
+
+ private PropListItem lookupProperty(int propType)
+ {
+ PropListItem x = propListHead;
+ while (x != null && propType != x.type) {
+ x = x.next;
+ }
+ return x;
+ }
+
+ private PropListItem ensureProperty(int propType)
+ {
+ PropListItem item = lookupProperty(propType);
+ if (item == null) {
+ item = new PropListItem();
+ item.type = propType;
+ item.next = propListHead;
+ propListHead = item;
+ }
+ return item;
+ }
+
+ public void removeProp(int propType)
+ {
+ PropListItem x = propListHead;
+ if (x != null) {
+ PropListItem prev = null;
+ while (x.type != propType) {
+ prev = x;
+ x = x.next;
+ if (x == null) { return; }
+ }
+ if (prev == null) {
+ propListHead = x.next;
+ } else {
+ prev.next = x.next;
+ }
+ }
+ }
+
+ public Object getProp(int propType)
+ {
+ PropListItem item = lookupProperty(propType);
+ if (item == null) { return null; }
+ return item.objectValue;
+ }
+
+ public int getIntProp(int propType, int defaultValue)
+ {
+ PropListItem item = lookupProperty(propType);
+ if (item == null) { return defaultValue; }
+ return item.intValue;
+ }
+
+ public int getExistingIntProp(int propType)
+ {
+ PropListItem item = lookupProperty(propType);
+ if (item == null) { Kit.codeBug(); }
+ return item.intValue;
+ }
+
+ public void putProp(int propType, Object prop)
+ {
+ if (prop == null) {
+ removeProp(propType);
+ } else {
+ PropListItem item = ensureProperty(propType);
+ item.objectValue = prop;
+ }
+ }
+
+ public void putIntProp(int propType, int prop)
+ {
+ PropListItem item = ensureProperty(propType);
+ item.intValue = prop;
+ }
+
+ public int getLineno() {
+ return lineno;
+ }
+
+ /** Can only be called when <tt>getType() == Token.NUMBER</tt> */
+ public final double getDouble() {
+ return ((NumberNode)this).number;
+ }
+
+ public final void setDouble(double number) {
+ ((NumberNode)this).number = number;
+ }
+
+ /** Can only be called when node has String context. */
+ public final String getString() {
+ return ((StringNode)this).str;
+ }
+
+ /** Can only be called when node has String context. */
+ public final void setString(String s) {
+ if (s == null) Kit.codeBug();
+ ((StringNode)this).str = s;
+ }
+
+ /** Can only be called when node has String context. */
+ public final Scope getScope() {
+ return ((StringNode)this).scope;
+ }
+
+ /** Can only be called when node has String context. */
+ public final void setScope(Scope s) {
+ if (s == null) Kit.codeBug();
+ if (!(this instanceof StringNode)) {
+ throw Kit.codeBug();
+ }
+ ((StringNode)this).scope = s;
+ }
+
+ public static Node newTarget()
+ {
+ return new Node(Token.TARGET);
+ }
+
+ public final int labelId()
+ {
+ if (type != Token.TARGET && type != Token.YIELD) Kit.codeBug();
+ return getIntProp(LABEL_ID_PROP, -1);
+ }
+
+ public void labelId(int labelId)
+ {
+ if (type != Token.TARGET && type != Token.YIELD) Kit.codeBug();
+ putIntProp(LABEL_ID_PROP, labelId);
+ }
+
+
+ /**
+ * Does consistent-return analysis on the function body when strict mode is
+ * enabled.
+ *
+ * function (x) { return (x+1) }
+ * is ok, but
+ * function (x) { if (x < 0) return (x+1); }
+ * is not becuase the function can potentially return a value when the
+ * condition is satisfied and if not, the function does not explicitly
+ * return value.
+ *
+ * This extends to checking mismatches such as "return" and "return <value>"
+ * used in the same function. Warnings are not emitted if inconsistent
+ * returns exist in code that can be statically shown to be unreachable.
+ * Ex.
+ * function (x) { while (true) { ... if (..) { return value } ... } }
+ * emits no warning. However if the loop had a break statement, then a
+ * warning would be emitted.
+ *
+ * The consistency analysis looks at control structures such as loops, ifs,
+ * switch, try-catch-finally blocks, examines the reachable code paths and
+ * warns the user about an inconsistent set of termination possibilities.
+ *
+ * Caveat: Since the parser flattens many control structures into almost
+ * straight-line code with gotos, it makes such analysis hard. Hence this
+ * analyser is written to taken advantage of patterns of code generated by
+ * the parser (for loops, try blocks and such) and does not do a full
+ * control flow analysis of the gotos and break/continue statements.
+ * Future changes to the parser will affect this analysis.
+ */
+
+ /**
+ * These flags enumerate the possible ways a statement/function can
+ * terminate. These flags are used by endCheck() and by the Parser to
+ * detect inconsistent return usage.
+ *
+ * END_UNREACHED is reserved for code paths that are assumed to always be
+ * able to execute (example: throw, continue)
+ *
+ * END_DROPS_OFF indicates if the statement can transfer control to the
+ * next one. Statement such as return dont. A compound statement may have
+ * some branch that drops off control to the next statement.
+ *
+ * END_RETURNS indicates that the statement can return (without arguments)
+ * END_RETURNS_VALUE indicates that the statement can return a value.
+ *
+ * A compound statement such as
+ * if (condition) {
+ * return value;
+ * }
+ * Will be detected as (END_DROPS_OFF | END_RETURN_VALUE) by endCheck()
+ */
+ static final int END_UNREACHED = 0;
+ static final int END_DROPS_OFF = 1;
+ static final int END_RETURNS = 2;
+ static final int END_RETURNS_VALUE = 4;
+ static final int END_YIELDS = 8;
+
+ /**
+ * Checks that every return usage in a function body is consistent with the
+ * requirements of strict-mode.
+ * @return true if the function satisfies strict mode requirement.
+ */
+ public boolean hasConsistentReturnUsage()
+ {
+ int n = endCheck();
+ return (n & END_RETURNS_VALUE) == 0 ||
+ (n & (END_DROPS_OFF|END_RETURNS|END_YIELDS)) == 0;
+ }
+
+ /**
+ * Returns in the then and else blocks must be consistent with each other.
+ * If there is no else block, then the return statement can fall through.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckIf()
+ {
+ Node th, el;
+ int rv = END_UNREACHED;
+
+ th = next;
+ el = ((Jump)this).target;
+
+ rv = th.endCheck();
+
+ if (el != null)
+ rv |= el.endCheck();
+ else
+ rv |= END_DROPS_OFF;
+
+ return rv;
+ }
+
+ /**
+ * Consistency of return statements is checked between the case statements.
+ * If there is no default, then the switch can fall through. If there is a
+ * default,we check to see if all code paths in the default return or if
+ * there is a code path that can fall through.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckSwitch()
+ {
+ Node n;
+ int rv = END_UNREACHED;
+
+ // examine the cases
+ for (n = first.next; n != null; n = n.next)
+ {
+ if (n.type == Token.CASE) {
+ rv |= ((Jump)n).target.endCheck();
+ } else
+ break;
+ }
+
+ // we don't care how the cases drop into each other
+ rv &= ~END_DROPS_OFF;
+
+ // examine the default
+ n = ((Jump)this).getDefault();
+ if (n != null)
+ rv |= n.endCheck();
+ else
+ rv |= END_DROPS_OFF;
+
+ // remove the switch block
+ rv |= getIntProp(CONTROL_BLOCK_PROP, END_UNREACHED);
+
+ return rv;
+ }
+
+ /**
+ * If the block has a finally, return consistency is checked in the
+ * finally block. If all code paths in the finally returns, then the
+ * returns in the try-catch blocks don't matter. If there is a code path
+ * that does not return or if there is no finally block, the returns
+ * of the try and catch blocks are checked for mismatch.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckTry()
+ {
+ Node n;
+ int rv = END_UNREACHED;
+
+ // check the finally if it exists
+ n = ((Jump)this).getFinally();
+ if(n != null) {
+ rv = n.next.first.endCheck();
+ } else {
+ rv = END_DROPS_OFF;
+ }
+
+ // if the finally block always returns, then none of the returns
+ // in the try or catch blocks matter
+ if ((rv & END_DROPS_OFF) != 0) {
+ rv &= ~END_DROPS_OFF;
+
+ // examine the try block
+ rv |= first.endCheck();
+
+ // check each catch block
+ n = ((Jump)this).target;
+ if (n != null)
+ {
+ // point to the first catch_scope
+ for (n = n.next.first; n != null; n = n.next.next)
+ {
+ // check the block of user code in the catch_scope
+ rv |= n.next.first.next.first.endCheck();
+ }
+ }
+ }
+
+ return rv;
+ }
+
+ /**
+ * Return statement in the loop body must be consistent. The default
+ * assumption for any kind of a loop is that it will eventually terminate.
+ * The only exception is a loop with a constant true condition. Code that
+ * follows such a loop is examined only if one can statically determine
+ * that there is a break out of the loop.
+ * for(<> ; <>; <>) {}
+ * for(<> in <> ) {}
+ * while(<>) { }
+ * do { } while(<>)
+ * @return logical OR of END_* flags
+ */
+ private int endCheckLoop()
+ {
+ Node n;
+ int rv = END_UNREACHED;
+
+ // To find the loop body, we look at the second to last node of the
+ // loop node, which should be the predicate that the loop should
+ // satisfy.
+ // The target of the predicate is the loop-body for all 4 kinds of
+ // loops.
+ for (n = first; n.next != last; n = n.next) {
+ /* skip */
+ }
+ if (n.type != Token.IFEQ)
+ return END_DROPS_OFF;
+
+ // The target's next is the loop body block
+ rv = ((Jump)n).target.next.endCheck();
+
+ // check to see if the loop condition is true
+ if (n.first.type == Token.TRUE)
+ rv &= ~END_DROPS_OFF;
+
+ // look for effect of breaks
+ rv |= getIntProp(CONTROL_BLOCK_PROP, END_UNREACHED);
+
+ return rv;
+ }
+
+
+ /**
+ * A general block of code is examined statement by statement. If any
+ * statement (even compound ones) returns in all branches, then subsequent
+ * statements are not examined.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckBlock()
+ {
+ Node n;
+ int rv = END_DROPS_OFF;
+
+ // check each statment and if the statement can continue onto the next
+ // one, then check the next statement
+ for (n=first; ((rv & END_DROPS_OFF) != 0) && n != null; n = n.next)
+ {
+ rv &= ~END_DROPS_OFF;
+ rv |= n.endCheck();
+ }
+ return rv;
+ }
+
+ /**
+ * A labelled statement implies that there maybe a break to the label. The
+ * function processes the labelled statement and then checks the
+ * CONTROL_BLOCK_PROP property to see if there is ever a break to the
+ * particular label.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckLabel()
+ {
+ int rv = END_UNREACHED;
+
+ rv = next.endCheck();
+ rv |= getIntProp(CONTROL_BLOCK_PROP, END_UNREACHED);
+
+ return rv;
+ }
+
+ /**
+ * When a break is encountered annotate the statement being broken
+ * out of by setting its CONTROL_BLOCK_PROP property.
+ * @return logical OR of END_* flags
+ */
+ private int endCheckBreak()
+ {
+ Node n = ((Jump) this).jumpNode;
+ n.putIntProp(CONTROL_BLOCK_PROP, END_DROPS_OFF);
+ return END_UNREACHED;
+ }
+
+ /**
+ * endCheck() examines the body of a function, doing a basic reachability
+ * analysis and returns a combination of flags END_* flags that indicate
+ * how the function execution can terminate. These constitute only the
+ * pessimistic set of termination conditions. It is possible that at
+ * runtime certain code paths will never be actually taken. Hence this
+ * analysis will flag errors in cases where there may not be errors.
+ * @return logical OR of END_* flags
+ */
+ private int endCheck()
+ {
+ switch(type)
+ {
+ case Token.BREAK:
+ return endCheckBreak();
+
+ case Token.EXPR_VOID:
+ if (this.first != null)
+ return first.endCheck();
+ return END_DROPS_OFF;
+
+ case Token.YIELD:
+ return END_YIELDS;
+
+ case Token.CONTINUE:
+ case Token.THROW:
+ return END_UNREACHED;
+
+ case Token.RETURN:
+ if (this.first != null)
+ return END_RETURNS_VALUE;
+ else
+ return END_RETURNS;
+
+ case Token.TARGET:
+ if (next != null)
+ return next.endCheck();
+ else
+ return END_DROPS_OFF;
+
+ case Token.LOOP:
+ return endCheckLoop();
+
+ case Token.LOCAL_BLOCK:
+ case Token.BLOCK:
+ // there are several special kinds of blocks
+ if (first == null)
+ return END_DROPS_OFF;
+
+ switch(first.type) {
+ case Token.LABEL:
+ return first.endCheckLabel();
+
+ case Token.IFNE:
+ return first.endCheckIf();
+
+ case Token.SWITCH:
+ return first.endCheckSwitch();
+
+ case Token.TRY:
+ return first.endCheckTry();
+
+ default:
+ return endCheckBlock();
+ }
+
+ default:
+ return END_DROPS_OFF;
+ }
+ }
+
+ public boolean hasSideEffects()
+ {
+ switch (type) {
+ case Token.EXPR_VOID:
+ case Token.COMMA:
+ if (last != null)
+ return last.hasSideEffects();
+ else
+ return true;
+
+ case Token.HOOK:
+ if (first == null ||
+ first.next == null ||
+ first.next.next == null)
+ Kit.codeBug();
+ return first.next.hasSideEffects() &&
+ first.next.next.hasSideEffects();
+
+ case Token.ERROR: // Avoid cascaded error messages
+ case Token.EXPR_RESULT:
+ case Token.ASSIGN:
+ case Token.ASSIGN_ADD:
+ case Token.ASSIGN_SUB:
+ case Token.ASSIGN_MUL:
+ case Token.ASSIGN_DIV:
+ case Token.ASSIGN_MOD:
+ case Token.ASSIGN_BITOR:
+ case Token.ASSIGN_BITXOR:
+ case Token.ASSIGN_BITAND:
+ case Token.ASSIGN_LSH:
+ case Token.ASSIGN_RSH:
+ case Token.ASSIGN_URSH:
+ case Token.ENTERWITH:
+ case Token.LEAVEWITH:
+ case Token.RETURN:
+ case Token.GOTO:
+ case Token.IFEQ:
+ case Token.IFNE:
+ case Token.NEW:
+ case Token.DELPROP:
+ case Token.SETNAME:
+ case Token.SETPROP:
+ case Token.SETELEM:
+ case Token.CALL:
+ case Token.THROW:
+ case Token.RETHROW:
+ case Token.SETVAR:
+ case Token.CATCH_SCOPE:
+ case Token.RETURN_RESULT:
+ case Token.SET_REF:
+ case Token.DEL_REF:
+ case Token.REF_CALL:
+ case Token.TRY:
+ case Token.SEMI:
+ case Token.INC:
+ case Token.DEC:
+ case Token.EXPORT:
+ case Token.IMPORT:
+ case Token.IF:
+ case Token.ELSE:
+ case Token.SWITCH:
+ case Token.WHILE:
+ case Token.DO:
+ case Token.FOR:
+ case Token.BREAK:
+ case Token.CONTINUE:
+ case Token.VAR:
+ case Token.CONST:
+ case Token.LET:
+ case Token.LETEXPR:
+ case Token.WITH:
+ case Token.WITHEXPR:
+ case Token.CATCH:
+ case Token.FINALLY:
+ case Token.BLOCK:
+ case Token.LABEL:
+ case Token.TARGET:
+ case Token.LOOP:
+ case Token.JSR:
+ case Token.SETPROP_OP:
+ case Token.SETELEM_OP:
+ case Token.LOCAL_BLOCK:
+ case Token.SET_REF_OP:
+ case Token.YIELD:
+ return true;
+
+ default:
+ return false;
+ }
+ }
+
+ public String toString()
+ {
+ if (Token.printTrees) {
+ StringBuffer sb = new StringBuffer();
+ toString(new ObjToIntMap(), sb);
+ return sb.toString();
+ }
+ return String.valueOf(type);
+ }
+
+ private void toString(ObjToIntMap printIds, StringBuffer sb)
+ {
+ if (Token.printTrees) {
+ sb.append(Token.name(type));
+ if (this instanceof StringNode) {
+ sb.append(' ');
+ sb.append(getString());
+ Scope scope = getScope();
+ if (scope != null) {
+ sb.append("[scope: ");
+ appendPrintId(scope, printIds, sb);
+ sb.append("]");
+ }
+ } else if (this instanceof Node.Scope) {
+ if (this instanceof ScriptOrFnNode) {
+ ScriptOrFnNode sof = (ScriptOrFnNode)this;
+ if (this instanceof FunctionNode) {
+ FunctionNode fn = (FunctionNode)this;
+ sb.append(' ');
+ sb.append(fn.getFunctionName());
+ }
+ sb.append(" [source name: ");
+ sb.append(sof.getSourceName());
+ sb.append("] [encoded source length: ");
+ sb.append(sof.getEncodedSourceEnd()
+ - sof.getEncodedSourceStart());
+ sb.append("] [base line: ");
+ sb.append(sof.getBaseLineno());
+ sb.append("] [end line: ");
+ sb.append(sof.getEndLineno());
+ sb.append(']');
+ }
+ if (((Node.Scope)this).symbolTable != null) {
+ sb.append(" [scope ");
+ appendPrintId(this, printIds, sb);
+ sb.append(": ");
+ Iterator iter = ((Node.Scope) this).symbolTable.keySet()
+ .iterator();
+ while (iter.hasNext()) {
+ sb.append(iter.next());
+ sb.append(" ");
+ }
+ sb.append("]");
+ }
+ } else if (this instanceof Jump) {
+ Jump jump = (Jump)this;
+ if (type == Token.BREAK || type == Token.CONTINUE) {
+ sb.append(" [label: ");
+ appendPrintId(jump.getJumpStatement(), printIds, sb);
+ sb.append(']');
+ } else if (type == Token.TRY) {
+ Node catchNode = jump.target;
+ Node finallyTarget = jump.getFinally();
+ if (catchNode != null) {
+ sb.append(" [catch: ");
+ appendPrintId(catchNode, printIds, sb);
+ sb.append(']');
+ }
+ if (finallyTarget != null) {
+ sb.append(" [finally: ");
+ appendPrintId(finallyTarget, printIds, sb);
+ sb.append(']');
+ }
+ } else if (type == Token.LABEL || type == Token.LOOP
+ || type == Token.SWITCH)
+ {
+ sb.append(" [break: ");
+ appendPrintId(jump.target, printIds, sb);
+ sb.append(']');
+ if (type == Token.LOOP) {
+ sb.append(" [continue: ");
+ appendPrintId(jump.getContinue(), printIds, sb);
+ sb.append(']');
+ }
+ } else {
+ sb.append(" [target: ");
+ appendPrintId(jump.target, printIds, sb);
+ sb.append(']');
+ }
+ } else if (type == Token.NUMBER) {
+ sb.append(' ');
+ sb.append(getDouble());
+ } else if (type == Token.TARGET) {
+ sb.append(' ');
+ appendPrintId(this, printIds, sb);
+ }
+ if (lineno != -1) {
+ sb.append(' ');
+ sb.append(lineno);
+ }
+
+ for (PropListItem x = propListHead; x != null; x = x.next) {
+ int type = x.type;
+ sb.append(" [");
+ sb.append(propToString(type));
+ sb.append(": ");
+ String value;
+ switch (type) {
+ case TARGETBLOCK_PROP : // can't add this as it recurses
+ value = "target block property";
+ break;
+ case LOCAL_BLOCK_PROP : // can't add this as it is dull
+ value = "last local block";
+ break;
+ case ISNUMBER_PROP:
+ switch (x.intValue) {
+ case BOTH:
+ value = "both";
+ break;
+ case RIGHT:
+ value = "right";
+ break;
+ case LEFT:
+ value = "left";
+ break;
+ default:
+ throw Kit.codeBug();
+ }
+ break;
+ case SPECIALCALL_PROP:
+ switch (x.intValue) {
+ case SPECIALCALL_EVAL:
+ value = "eval";
+ break;
+ case SPECIALCALL_WITH:
+ value = "with";
+ break;
+ default:
+ // NON_SPECIALCALL should not be stored
+ throw Kit.codeBug();
+ }
+ break;
+ case OBJECT_IDS_PROP: {
+ Object[] a = (Object[]) x.objectValue;
+ value = "[";
+ for (int i=0; i < a.length; i++) {
+ value += a[i].toString();
+ if (i+1 < a.length)
+ value += ", ";
+ }
+ value += "]";
+ break;
+ }
+ default :
+ Object obj = x.objectValue;
+ if (obj != null) {
+ value = obj.toString();
+ } else {
+ value = String.valueOf(x.intValue);
+ }
+ break;
+ }
+ sb.append(value);
+ sb.append(']');
+ }
+ }
+ }
+
+ public String toStringTree(ScriptOrFnNode treeTop) {
+ if (Token.printTrees) {
+ StringBuffer sb = new StringBuffer();
+ toStringTreeHelper(treeTop, this, null, 0, sb);
+ return sb.toString();
+ }
+ return null;
+ }
+
+ private static void toStringTreeHelper(ScriptOrFnNode treeTop, Node n,
+ ObjToIntMap printIds,
+ int level, StringBuffer sb)
+ {
+ if (Token.printTrees) {
+ if (printIds == null) {
+ printIds = new ObjToIntMap();
+ generatePrintIds(treeTop, printIds);
+ }
+ for (int i = 0; i != level; ++i) {
+ sb.append(" ");
+ }
+ n.toString(printIds, sb);
+ sb.append('\n');
+ for (Node cursor = n.getFirstChild(); cursor != null;
+ cursor = cursor.getNext())
+ {
+ if (cursor.getType() == Token.FUNCTION) {
+ int fnIndex = cursor.getExistingIntProp(Node.FUNCTION_PROP);
+ FunctionNode fn = treeTop.getFunctionNode(fnIndex);
+ toStringTreeHelper(fn, fn, null, level + 1, sb);
+ } else {
+ toStringTreeHelper(treeTop, cursor, printIds, level + 1, sb);
+ }
+ }
+ }
+ }
+
+ private static void generatePrintIds(Node n, ObjToIntMap map)
+ {
+ if (Token.printTrees) {
+ map.put(n, map.size());
+ for (Node cursor = n.getFirstChild(); cursor != null;
+ cursor = cursor.getNext())
+ {
+ generatePrintIds(cursor, map);
+ }
+ }
+ }
+
+ private static void appendPrintId(Node n, ObjToIntMap printIds,
+ StringBuffer sb)
+ {
+ if (Token.printTrees) {
+ if (n != null) {
+ int id = printIds.get(n, -1);
+ sb.append('#');
+ if (id != -1) {
+ sb.append(id + 1);
+ } else {
+ sb.append("<not_available>");
+ }
+ }
+ }
+ }
+
+ int type; // type of the node; Token.NAME for example
+ Node next; // next sibling
+ private Node first; // first element of a linked list of children
+ private Node last; // last element of a linked list of children
+ protected int lineno = -1;
+
+ /*APPJET*/public int statementEndLineNum = -1;
+
+ /**
+ * Linked list of properties. Since vast majority of nodes would have
+ * no more then 2 properties, linked list saves memory and provides
+ * fast lookup. If this does not holds, propListHead can be replaced
+ * by UintMap.
+ */
+ private PropListItem propListHead;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-18 11:13:31 +0000