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/*
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* Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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//todo: one might eliminate uninits.andSets when monotonic
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package com.sun.tools.javac.comp;
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import com.sun.tools.javac.code.*;
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import com.sun.tools.javac.tree.*;
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import com.sun.tools.javac.util.*;
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import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
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import com.sun.tools.javac.code.Symbol.*;
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import com.sun.tools.javac.tree.JCTree.*;
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import static com.sun.tools.javac.code.Flags.*;
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import static com.sun.tools.javac.code.Kinds.*;
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import static com.sun.tools.javac.code.TypeTags.*;
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/** This pass implements dataflow analysis for Java programs.
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* Liveness analysis checks that every statement is reachable.
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* Exception analysis ensures that every checked exception that is
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* thrown is declared or caught. Definite assignment analysis
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* ensures that each variable is assigned when used. Definite
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* unassignment analysis ensures that no final variable is assigned
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* more than once.
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*
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* <p>The second edition of the JLS has a number of problems in the
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* specification of these flow analysis problems. This implementation
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* attempts to address those issues.
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*
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* <p>First, there is no accommodation for a finally clause that cannot
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* complete normally. For liveness analysis, an intervening finally
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* clause can cause a break, continue, or return not to reach its
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* target. For exception analysis, an intervening finally clause can
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* cause any exception to be "caught". For DA/DU analysis, the finally
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* clause can prevent a transfer of control from propagating DA/DU
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* state to the target. In addition, code in the finally clause can
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* affect the DA/DU status of variables.
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*
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* <p>For try statements, we introduce the idea of a variable being
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* definitely unassigned "everywhere" in a block. A variable V is
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* "unassigned everywhere" in a block iff it is unassigned at the
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* beginning of the block and there is no reachable assignment to V
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* in the block. An assignment V=e is reachable iff V is not DA
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* after e. Then we can say that V is DU at the beginning of the
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* catch block iff V is DU everywhere in the try block. Similarly, V
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* is DU at the beginning of the finally block iff V is DU everywhere
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* in the try block and in every catch block. Specifically, the
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* following bullet is added to 16.2.2
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* <pre>
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* V is <em>unassigned everywhere</em> in a block if it is
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* unassigned before the block and there is no reachable
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* assignment to V within the block.
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* </pre>
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* <p>In 16.2.15, the third bullet (and all of its sub-bullets) for all
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* try blocks is changed to
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* <pre>
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* V is definitely unassigned before a catch block iff V is
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* definitely unassigned everywhere in the try block.
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* </pre>
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* <p>The last bullet (and all of its sub-bullets) for try blocks that
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* have a finally block is changed to
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* <pre>
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* V is definitely unassigned before the finally block iff
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* V is definitely unassigned everywhere in the try block
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* and everywhere in each catch block of the try statement.
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* </pre>
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* <p>In addition,
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* <pre>
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* V is definitely assigned at the end of a constructor iff
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* V is definitely assigned after the block that is the body
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* of the constructor and V is definitely assigned at every
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* return that can return from the constructor.
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* </pre>
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* <p>In addition, each continue statement with the loop as its target
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* is treated as a jump to the end of the loop body, and "intervening"
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* finally clauses are treated as follows: V is DA "due to the
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* continue" iff V is DA before the continue statement or V is DA at
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* the end of any intervening finally block. V is DU "due to the
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* continue" iff any intervening finally cannot complete normally or V
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* is DU at the end of every intervening finally block. This "due to
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* the continue" concept is then used in the spec for the loops.
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*
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* <p>Similarly, break statements must consider intervening finally
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* blocks. For liveness analysis, a break statement for which any
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* intervening finally cannot complete normally is not considered to
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* cause the target statement to be able to complete normally. Then
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* we say V is DA "due to the break" iff V is DA before the break or
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* V is DA at the end of any intervening finally block. V is DU "due
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* to the break" iff any intervening finally cannot complete normally
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* or V is DU at the break and at the end of every intervening
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* finally block. (I suspect this latter condition can be
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* simplified.) This "due to the break" is then used in the spec for
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* all statements that can be "broken".
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*
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* <p>The return statement is treated similarly. V is DA "due to a
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* return statement" iff V is DA before the return statement or V is
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* DA at the end of any intervening finally block. Note that we
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* don't have to worry about the return expression because this
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* concept is only used for construcrors.
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*
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* <p>There is no spec in JLS2 for when a variable is definitely
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* assigned at the end of a constructor, which is needed for final
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* fields (8.3.1.2). We implement the rule that V is DA at the end
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* of the constructor iff it is DA and the end of the body of the
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* constructor and V is DA "due to" every return of the constructor.
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*
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* <p>Intervening finally blocks similarly affect exception analysis. An
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* intervening finally that cannot complete normally allows us to ignore
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* an otherwise uncaught exception.
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*
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* <p>To implement the semantics of intervening finally clauses, all
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* nonlocal transfers (break, continue, return, throw, method call that
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* can throw a checked exception, and a constructor invocation that can
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* thrown a checked exception) are recorded in a queue, and removed
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* from the queue when we complete processing the target of the
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* nonlocal transfer. This allows us to modify the queue in accordance
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* with the above rules when we encounter a finally clause. The only
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* exception to this [no pun intended] is that checked exceptions that
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* are known to be caught or declared to be caught in the enclosing
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* method are not recorded in the queue, but instead are recorded in a
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* global variable "Set<Type> thrown" that records the type of all
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* exceptions that can be thrown.
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*
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* <p>Other minor issues the treatment of members of other classes
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* (always considered DA except that within an anonymous class
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* constructor, where DA status from the enclosing scope is
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* preserved), treatment of the case expression (V is DA before the
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* case expression iff V is DA after the switch expression),
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* treatment of variables declared in a switch block (the implied
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* DA/DU status after the switch expression is DU and not DA for
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* variables defined in a switch block), the treatment of boolean ?:
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* expressions (The JLS rules only handle b and c non-boolean; the
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* new rule is that if b and c are boolean valued, then V is
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* (un)assigned after a?b:c when true/false iff V is (un)assigned
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* after b when true/false and V is (un)assigned after c when
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* true/false).
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*
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* <p>There is the remaining question of what syntactic forms constitute a
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* reference to a variable. It is conventional to allow this.x on the
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* left-hand-side to initialize a final instance field named x, yet
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* this.x isn't considered a "use" when appearing on a right-hand-side
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* in most implementations. Should parentheses affect what is
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* considered a variable reference? The simplest rule would be to
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* allow unqualified forms only, parentheses optional, and phase out
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* support for assigning to a final field via this.x.
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*
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* <p><b>This is NOT part of any API supported by Sun Microsystems. If
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* you write code that depends on this, you do so at your own risk.
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* This code and its internal interfaces are subject to change or
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* deletion without notice.</b>
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*/
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public class Flow extends TreeScanner {
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protected static final Context.Key<Flow> flowKey =
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new Context.Key<Flow>();
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private final Name.Table names;
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private final Log log;
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private final Symtab syms;
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private final Types types;
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private final Check chk;
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private TreeMaker make;
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private Lint lint;
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public static Flow instance(Context context) {
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Flow instance = context.get(flowKey);
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if (instance == null)
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instance = new Flow(context);
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return instance;
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}
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protected Flow(Context context) {
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context.put(flowKey, this);
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names = Name.Table.instance(context);
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log = Log.instance(context);
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syms = Symtab.instance(context);
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types = Types.instance(context);
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chk = Check.instance(context);
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lint = Lint.instance(context);
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}
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/** A flag that indicates whether the last statement could
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* complete normally.
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*/
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private boolean alive;
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/** The set of definitely assigned variables.
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*/
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Bits inits;
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/** The set of definitely unassigned variables.
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*/
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Bits uninits;
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/** The set of variables that are definitely unassigned everywhere
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* in current try block. This variable is maintained lazily; it is
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* updated only when something gets removed from uninits,
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* typically by being assigned in reachable code. To obtain the
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* correct set of variables which are definitely unassigned
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* anywhere in current try block, intersect uninitsTry and
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* uninits.
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*/
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Bits uninitsTry;
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/** When analyzing a condition, inits and uninits are null.
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* Instead we have:
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*/
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Bits initsWhenTrue;
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Bits initsWhenFalse;
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Bits uninitsWhenTrue;
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Bits uninitsWhenFalse;
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/** A mapping from addresses to variable symbols.
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*/
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VarSymbol[] vars;
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/** The current class being defined.
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*/
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JCClassDecl classDef;
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/** The first variable sequence number in this class definition.
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*/
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int firstadr;
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/** The next available variable sequence number.
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*/
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int nextadr;
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/** The list of possibly thrown declarable exceptions.
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*/
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List<Type> thrown;
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/** The list of exceptions that are either caught or declared to be
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* thrown.
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*/
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List<Type> caught;
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/** Set when processing a loop body the second time for DU analysis. */
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boolean loopPassTwo = false;
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/*-------------------- Environments ----------------------*/
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/** A pending exit. These are the statements return, break, and
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* continue. In addition, exception-throwing expressions or
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* statements are put here when not known to be caught. This
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* will typically result in an error unless it is within a
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* try-finally whose finally block cannot complete normally.
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*/
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static class PendingExit {
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JCTree tree;
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Bits inits;
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Bits uninits;
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Type thrown;
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PendingExit(JCTree tree, Bits inits, Bits uninits) {
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this.tree = tree;
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this.inits = inits.dup();
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this.uninits = uninits.dup();
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}
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PendingExit(JCTree tree, Type thrown) {
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this.tree = tree;
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this.thrown = thrown;
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}
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}
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/** The currently pending exits that go from current inner blocks
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* to an enclosing block, in source order.
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*/
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ListBuffer<PendingExit> pendingExits;
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/*-------------------- Exceptions ----------------------*/
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/** Complain that pending exceptions are not caught.
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*/
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void errorUncaught() {
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for (PendingExit exit = pendingExits.next();
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exit != null;
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exit = pendingExits.next()) {
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boolean synthetic = classDef != null &&
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classDef.pos == exit.tree.pos;
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log.error(exit.tree.pos(),
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synthetic
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? "unreported.exception.default.constructor"
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: "unreported.exception.need.to.catch.or.throw",
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exit.thrown);
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}
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}
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/** Record that exception is potentially thrown and check that it
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* is caught.
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*/
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void markThrown(JCTree tree, Type exc) {
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if (!chk.isUnchecked(tree.pos(), exc)) {
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if (!chk.isHandled(exc, caught))
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pendingExits.append(new PendingExit(tree, exc));
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thrown = chk.incl(exc, thrown);
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}
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}
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/*-------------- Processing variables ----------------------*/
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/** Do we need to track init/uninit state of this symbol?
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* I.e. is symbol either a local or a blank final variable?
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*/
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boolean trackable(VarSymbol sym) {
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return
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(sym.owner.kind == MTH ||
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((sym.flags() & (FINAL | HASINIT | PARAMETER)) == FINAL &&
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classDef.sym.isEnclosedBy((ClassSymbol)sym.owner)));
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}
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/** Initialize new trackable variable by setting its address field
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* to the next available sequence number and entering it under that
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* index into the vars array.
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*/
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void newVar(VarSymbol sym) {
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if (nextadr == vars.length) {
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VarSymbol[] newvars = new VarSymbol[nextadr * 2];
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System.arraycopy(vars, 0, newvars, 0, nextadr);
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vars = newvars;
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}
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sym.adr = nextadr;
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vars[nextadr] = sym;
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inits.excl(nextadr);
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uninits.incl(nextadr);
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nextadr++;
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}
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/** Record an initialization of a trackable variable.
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*/
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void letInit(DiagnosticPosition pos, VarSymbol sym) {
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if (sym.adr >= firstadr && trackable(sym)) {
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if ((sym.flags() & FINAL) != 0) {
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if ((sym.flags() & PARAMETER) != 0) {
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log.error(pos, "final.parameter.may.not.be.assigned",
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sym);
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} else if (!uninits.isMember(sym.adr)) {
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log.error(pos,
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loopPassTwo
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? "var.might.be.assigned.in.loop"
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: "var.might.already.be.assigned",
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sym);
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} else if (!inits.isMember(sym.adr)) {
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// reachable assignment
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uninits.excl(sym.adr);
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uninitsTry.excl(sym.adr);
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} else {
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//log.rawWarning(pos, "unreachable assignment");//DEBUG
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uninits.excl(sym.adr);
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}
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}
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inits.incl(sym.adr);
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} else if ((sym.flags() & FINAL) != 0) {
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log.error(pos, "var.might.already.be.assigned", sym);
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}
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}
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/** If tree is either a simple name or of the form this.name or
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* C.this.name, and tree represents a trackable variable,
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* record an initialization of the variable.
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*/
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void letInit(JCTree tree) {
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tree = TreeInfo.skipParens(tree);
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if (tree.getTag() == JCTree.IDENT || tree.getTag() == JCTree.SELECT) {
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Symbol sym = TreeInfo.symbol(tree);
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letInit(tree.pos(), (VarSymbol)sym);
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}
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}
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|
393 |
/** Check that trackable variable is initialized.
|
|
394 |
*/
|
|
395 |
void checkInit(DiagnosticPosition pos, VarSymbol sym) {
|
|
396 |
if ((sym.adr >= firstadr || sym.owner.kind != TYP) &&
|
|
397 |
trackable(sym) &&
|
|
398 |
!inits.isMember(sym.adr)) {
|
|
399 |
log.error(pos, "var.might.not.have.been.initialized",
|
|
400 |
sym);
|
|
401 |
inits.incl(sym.adr);
|
|
402 |
}
|
|
403 |
}
|
|
404 |
|
|
405 |
/*-------------------- Handling jumps ----------------------*/
|
|
406 |
|
|
407 |
/** Record an outward transfer of control. */
|
|
408 |
void recordExit(JCTree tree) {
|
|
409 |
pendingExits.append(new PendingExit(tree, inits, uninits));
|
|
410 |
markDead();
|
|
411 |
}
|
|
412 |
|
|
413 |
/** Resolve all breaks of this statement. */
|
|
414 |
boolean resolveBreaks(JCTree tree,
|
|
415 |
ListBuffer<PendingExit> oldPendingExits) {
|
|
416 |
boolean result = false;
|
|
417 |
List<PendingExit> exits = pendingExits.toList();
|
|
418 |
pendingExits = oldPendingExits;
|
|
419 |
for (; exits.nonEmpty(); exits = exits.tail) {
|
|
420 |
PendingExit exit = exits.head;
|
|
421 |
if (exit.tree.getTag() == JCTree.BREAK &&
|
|
422 |
((JCBreak) exit.tree).target == tree) {
|
|
423 |
inits.andSet(exit.inits);
|
|
424 |
uninits.andSet(exit.uninits);
|
|
425 |
result = true;
|
|
426 |
} else {
|
|
427 |
pendingExits.append(exit);
|
|
428 |
}
|
|
429 |
}
|
|
430 |
return result;
|
|
431 |
}
|
|
432 |
|
|
433 |
/** Resolve all continues of this statement. */
|
|
434 |
boolean resolveContinues(JCTree tree) {
|
|
435 |
boolean result = false;
|
|
436 |
List<PendingExit> exits = pendingExits.toList();
|
|
437 |
pendingExits = new ListBuffer<PendingExit>();
|
|
438 |
for (; exits.nonEmpty(); exits = exits.tail) {
|
|
439 |
PendingExit exit = exits.head;
|
|
440 |
if (exit.tree.getTag() == JCTree.CONTINUE &&
|
|
441 |
((JCContinue) exit.tree).target == tree) {
|
|
442 |
inits.andSet(exit.inits);
|
|
443 |
uninits.andSet(exit.uninits);
|
|
444 |
result = true;
|
|
445 |
} else {
|
|
446 |
pendingExits.append(exit);
|
|
447 |
}
|
|
448 |
}
|
|
449 |
return result;
|
|
450 |
}
|
|
451 |
|
|
452 |
/** Record that statement is unreachable.
|
|
453 |
*/
|
|
454 |
void markDead() {
|
|
455 |
inits.inclRange(firstadr, nextadr);
|
|
456 |
uninits.inclRange(firstadr, nextadr);
|
|
457 |
alive = false;
|
|
458 |
}
|
|
459 |
|
|
460 |
/** Split (duplicate) inits/uninits into WhenTrue/WhenFalse sets
|
|
461 |
*/
|
|
462 |
void split() {
|
|
463 |
initsWhenFalse = inits.dup();
|
|
464 |
uninitsWhenFalse = uninits.dup();
|
|
465 |
initsWhenTrue = inits;
|
|
466 |
uninitsWhenTrue = uninits;
|
|
467 |
inits = uninits = null;
|
|
468 |
}
|
|
469 |
|
|
470 |
/** Merge (intersect) inits/uninits from WhenTrue/WhenFalse sets.
|
|
471 |
*/
|
|
472 |
void merge() {
|
|
473 |
inits = initsWhenFalse.andSet(initsWhenTrue);
|
|
474 |
uninits = uninitsWhenFalse.andSet(uninitsWhenTrue);
|
|
475 |
}
|
|
476 |
|
|
477 |
/* ************************************************************************
|
|
478 |
* Visitor methods for statements and definitions
|
|
479 |
*************************************************************************/
|
|
480 |
|
|
481 |
/** Analyze a definition.
|
|
482 |
*/
|
|
483 |
void scanDef(JCTree tree) {
|
|
484 |
scanStat(tree);
|
|
485 |
if (tree != null && tree.getTag() == JCTree.BLOCK && !alive) {
|
|
486 |
log.error(tree.pos(),
|
|
487 |
"initializer.must.be.able.to.complete.normally");
|
|
488 |
}
|
|
489 |
}
|
|
490 |
|
|
491 |
/** Analyze a statement. Check that statement is reachable.
|
|
492 |
*/
|
|
493 |
void scanStat(JCTree tree) {
|
|
494 |
if (!alive && tree != null) {
|
|
495 |
log.error(tree.pos(), "unreachable.stmt");
|
|
496 |
if (tree.getTag() != JCTree.SKIP) alive = true;
|
|
497 |
}
|
|
498 |
scan(tree);
|
|
499 |
}
|
|
500 |
|
|
501 |
/** Analyze list of statements.
|
|
502 |
*/
|
|
503 |
void scanStats(List<? extends JCStatement> trees) {
|
|
504 |
if (trees != null)
|
|
505 |
for (List<? extends JCStatement> l = trees; l.nonEmpty(); l = l.tail)
|
|
506 |
scanStat(l.head);
|
|
507 |
}
|
|
508 |
|
|
509 |
/** Analyze an expression. Make sure to set (un)inits rather than
|
|
510 |
* (un)initsWhenTrue(WhenFalse) on exit.
|
|
511 |
*/
|
|
512 |
void scanExpr(JCTree tree) {
|
|
513 |
if (tree != null) {
|
|
514 |
scan(tree);
|
|
515 |
if (inits == null) merge();
|
|
516 |
}
|
|
517 |
}
|
|
518 |
|
|
519 |
/** Analyze a list of expressions.
|
|
520 |
*/
|
|
521 |
void scanExprs(List<? extends JCExpression> trees) {
|
|
522 |
if (trees != null)
|
|
523 |
for (List<? extends JCExpression> l = trees; l.nonEmpty(); l = l.tail)
|
|
524 |
scanExpr(l.head);
|
|
525 |
}
|
|
526 |
|
|
527 |
/** Analyze a condition. Make sure to set (un)initsWhenTrue(WhenFalse)
|
|
528 |
* rather than (un)inits on exit.
|
|
529 |
*/
|
|
530 |
void scanCond(JCTree tree) {
|
|
531 |
if (tree.type.isFalse()) {
|
|
532 |
if (inits == null) merge();
|
|
533 |
initsWhenTrue = inits.dup();
|
|
534 |
initsWhenTrue.inclRange(firstadr, nextadr);
|
|
535 |
uninitsWhenTrue = uninits.dup();
|
|
536 |
uninitsWhenTrue.inclRange(firstadr, nextadr);
|
|
537 |
initsWhenFalse = inits;
|
|
538 |
uninitsWhenFalse = uninits;
|
|
539 |
} else if (tree.type.isTrue()) {
|
|
540 |
if (inits == null) merge();
|
|
541 |
initsWhenFalse = inits.dup();
|
|
542 |
initsWhenFalse.inclRange(firstadr, nextadr);
|
|
543 |
uninitsWhenFalse = uninits.dup();
|
|
544 |
uninitsWhenFalse.inclRange(firstadr, nextadr);
|
|
545 |
initsWhenTrue = inits;
|
|
546 |
uninitsWhenTrue = uninits;
|
|
547 |
} else {
|
|
548 |
scan(tree);
|
|
549 |
if (inits != null) split();
|
|
550 |
}
|
|
551 |
inits = uninits = null;
|
|
552 |
}
|
|
553 |
|
|
554 |
/* ------------ Visitor methods for various sorts of trees -------------*/
|
|
555 |
|
|
556 |
public void visitClassDef(JCClassDecl tree) {
|
|
557 |
if (tree.sym == null) return;
|
|
558 |
|
|
559 |
JCClassDecl classDefPrev = classDef;
|
|
560 |
List<Type> thrownPrev = thrown;
|
|
561 |
List<Type> caughtPrev = caught;
|
|
562 |
boolean alivePrev = alive;
|
|
563 |
int firstadrPrev = firstadr;
|
|
564 |
int nextadrPrev = nextadr;
|
|
565 |
ListBuffer<PendingExit> pendingExitsPrev = pendingExits;
|
|
566 |
Lint lintPrev = lint;
|
|
567 |
|
|
568 |
pendingExits = new ListBuffer<PendingExit>();
|
|
569 |
if (tree.name != names.empty) {
|
|
570 |
caught = List.nil();
|
|
571 |
firstadr = nextadr;
|
|
572 |
}
|
|
573 |
classDef = tree;
|
|
574 |
thrown = List.nil();
|
|
575 |
lint = lint.augment(tree.sym.attributes_field);
|
|
576 |
|
|
577 |
try {
|
|
578 |
// define all the static fields
|
|
579 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
580 |
if (l.head.getTag() == JCTree.VARDEF) {
|
|
581 |
JCVariableDecl def = (JCVariableDecl)l.head;
|
|
582 |
if ((def.mods.flags & STATIC) != 0) {
|
|
583 |
VarSymbol sym = def.sym;
|
|
584 |
if (trackable(sym))
|
|
585 |
newVar(sym);
|
|
586 |
}
|
|
587 |
}
|
|
588 |
}
|
|
589 |
|
|
590 |
// process all the static initializers
|
|
591 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
592 |
if (l.head.getTag() != JCTree.METHODDEF &&
|
|
593 |
(TreeInfo.flags(l.head) & STATIC) != 0) {
|
|
594 |
scanDef(l.head);
|
|
595 |
errorUncaught();
|
|
596 |
}
|
|
597 |
}
|
|
598 |
|
|
599 |
// add intersection of all thrown clauses of initial constructors
|
|
600 |
// to set of caught exceptions, unless class is anonymous.
|
|
601 |
if (tree.name != names.empty) {
|
|
602 |
boolean firstConstructor = true;
|
|
603 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
604 |
if (TreeInfo.isInitialConstructor(l.head)) {
|
|
605 |
List<Type> mthrown =
|
|
606 |
((JCMethodDecl) l.head).sym.type.getThrownTypes();
|
|
607 |
if (firstConstructor) {
|
|
608 |
caught = mthrown;
|
|
609 |
firstConstructor = false;
|
|
610 |
} else {
|
|
611 |
caught = chk.intersect(mthrown, caught);
|
|
612 |
}
|
|
613 |
}
|
|
614 |
}
|
|
615 |
}
|
|
616 |
|
|
617 |
// define all the instance fields
|
|
618 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
619 |
if (l.head.getTag() == JCTree.VARDEF) {
|
|
620 |
JCVariableDecl def = (JCVariableDecl)l.head;
|
|
621 |
if ((def.mods.flags & STATIC) == 0) {
|
|
622 |
VarSymbol sym = def.sym;
|
|
623 |
if (trackable(sym))
|
|
624 |
newVar(sym);
|
|
625 |
}
|
|
626 |
}
|
|
627 |
}
|
|
628 |
|
|
629 |
// process all the instance initializers
|
|
630 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
631 |
if (l.head.getTag() != JCTree.METHODDEF &&
|
|
632 |
(TreeInfo.flags(l.head) & STATIC) == 0) {
|
|
633 |
scanDef(l.head);
|
|
634 |
errorUncaught();
|
|
635 |
}
|
|
636 |
}
|
|
637 |
|
|
638 |
// in an anonymous class, add the set of thrown exceptions to
|
|
639 |
// the throws clause of the synthetic constructor and propagate
|
|
640 |
// outwards.
|
|
641 |
if (tree.name == names.empty) {
|
|
642 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
643 |
if (TreeInfo.isInitialConstructor(l.head)) {
|
|
644 |
JCMethodDecl mdef = (JCMethodDecl)l.head;
|
|
645 |
mdef.thrown = make.Types(thrown);
|
|
646 |
mdef.sym.type.setThrown(thrown);
|
|
647 |
}
|
|
648 |
}
|
|
649 |
thrownPrev = chk.union(thrown, thrownPrev);
|
|
650 |
}
|
|
651 |
|
|
652 |
// process all the methods
|
|
653 |
for (List<JCTree> l = tree.defs; l.nonEmpty(); l = l.tail) {
|
|
654 |
if (l.head.getTag() == JCTree.METHODDEF) {
|
|
655 |
scan(l.head);
|
|
656 |
errorUncaught();
|
|
657 |
}
|
|
658 |
}
|
|
659 |
|
|
660 |
thrown = thrownPrev;
|
|
661 |
} finally {
|
|
662 |
pendingExits = pendingExitsPrev;
|
|
663 |
alive = alivePrev;
|
|
664 |
nextadr = nextadrPrev;
|
|
665 |
firstadr = firstadrPrev;
|
|
666 |
caught = caughtPrev;
|
|
667 |
classDef = classDefPrev;
|
|
668 |
lint = lintPrev;
|
|
669 |
}
|
|
670 |
}
|
|
671 |
|
|
672 |
public void visitMethodDef(JCMethodDecl tree) {
|
|
673 |
if (tree.body == null) return;
|
|
674 |
|
|
675 |
List<Type> caughtPrev = caught;
|
|
676 |
List<Type> mthrown = tree.sym.type.getThrownTypes();
|
|
677 |
Bits initsPrev = inits.dup();
|
|
678 |
Bits uninitsPrev = uninits.dup();
|
|
679 |
int nextadrPrev = nextadr;
|
|
680 |
int firstadrPrev = firstadr;
|
|
681 |
Lint lintPrev = lint;
|
|
682 |
|
|
683 |
lint = lint.augment(tree.sym.attributes_field);
|
|
684 |
|
|
685 |
assert pendingExits.isEmpty();
|
|
686 |
|
|
687 |
try {
|
|
688 |
boolean isInitialConstructor =
|
|
689 |
TreeInfo.isInitialConstructor(tree);
|
|
690 |
|
|
691 |
if (!isInitialConstructor)
|
|
692 |
firstadr = nextadr;
|
|
693 |
for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
|
|
694 |
JCVariableDecl def = l.head;
|
|
695 |
scan(def);
|
|
696 |
inits.incl(def.sym.adr);
|
|
697 |
uninits.excl(def.sym.adr);
|
|
698 |
}
|
|
699 |
if (isInitialConstructor)
|
|
700 |
caught = chk.union(caught, mthrown);
|
|
701 |
else if ((tree.sym.flags() & (BLOCK | STATIC)) != BLOCK)
|
|
702 |
caught = mthrown;
|
|
703 |
// else we are in an instance initializer block;
|
|
704 |
// leave caught unchanged.
|
|
705 |
|
|
706 |
alive = true;
|
|
707 |
scanStat(tree.body);
|
|
708 |
|
|
709 |
if (alive && tree.sym.type.getReturnType().tag != VOID)
|
|
710 |
log.error(TreeInfo.diagEndPos(tree.body), "missing.ret.stmt");
|
|
711 |
|
|
712 |
if (isInitialConstructor) {
|
|
713 |
for (int i = firstadr; i < nextadr; i++)
|
|
714 |
if (vars[i].owner == classDef.sym)
|
|
715 |
checkInit(TreeInfo.diagEndPos(tree.body), vars[i]);
|
|
716 |
}
|
|
717 |
List<PendingExit> exits = pendingExits.toList();
|
|
718 |
pendingExits = new ListBuffer<PendingExit>();
|
|
719 |
while (exits.nonEmpty()) {
|
|
720 |
PendingExit exit = exits.head;
|
|
721 |
exits = exits.tail;
|
|
722 |
if (exit.thrown == null) {
|
|
723 |
assert exit.tree.getTag() == JCTree.RETURN;
|
|
724 |
if (isInitialConstructor) {
|
|
725 |
inits = exit.inits;
|
|
726 |
for (int i = firstadr; i < nextadr; i++)
|
|
727 |
checkInit(exit.tree.pos(), vars[i]);
|
|
728 |
}
|
|
729 |
} else {
|
|
730 |
// uncaught throws will be reported later
|
|
731 |
pendingExits.append(exit);
|
|
732 |
}
|
|
733 |
}
|
|
734 |
} finally {
|
|
735 |
inits = initsPrev;
|
|
736 |
uninits = uninitsPrev;
|
|
737 |
nextadr = nextadrPrev;
|
|
738 |
firstadr = firstadrPrev;
|
|
739 |
caught = caughtPrev;
|
|
740 |
lint = lintPrev;
|
|
741 |
}
|
|
742 |
}
|
|
743 |
|
|
744 |
public void visitVarDef(JCVariableDecl tree) {
|
|
745 |
boolean track = trackable(tree.sym);
|
|
746 |
if (track && tree.sym.owner.kind == MTH) newVar(tree.sym);
|
|
747 |
if (tree.init != null) {
|
|
748 |
Lint lintPrev = lint;
|
|
749 |
lint = lint.augment(tree.sym.attributes_field);
|
|
750 |
try{
|
|
751 |
scanExpr(tree.init);
|
|
752 |
if (track) letInit(tree.pos(), tree.sym);
|
|
753 |
} finally {
|
|
754 |
lint = lintPrev;
|
|
755 |
}
|
|
756 |
}
|
|
757 |
}
|
|
758 |
|
|
759 |
public void visitBlock(JCBlock tree) {
|
|
760 |
int nextadrPrev = nextadr;
|
|
761 |
scanStats(tree.stats);
|
|
762 |
nextadr = nextadrPrev;
|
|
763 |
}
|
|
764 |
|
|
765 |
public void visitDoLoop(JCDoWhileLoop tree) {
|
|
766 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
767 |
boolean prevLoopPassTwo = loopPassTwo;
|
|
768 |
pendingExits = new ListBuffer<PendingExit>();
|
|
769 |
do {
|
|
770 |
Bits uninitsEntry = uninits.dup();
|
|
771 |
scanStat(tree.body);
|
|
772 |
alive |= resolveContinues(tree);
|
|
773 |
scanCond(tree.cond);
|
|
774 |
if (log.nerrors != 0 ||
|
|
775 |
loopPassTwo ||
|
|
776 |
uninitsEntry.diffSet(uninitsWhenTrue).nextBit(firstadr)==-1)
|
|
777 |
break;
|
|
778 |
inits = initsWhenTrue;
|
|
779 |
uninits = uninitsEntry.andSet(uninitsWhenTrue);
|
|
780 |
loopPassTwo = true;
|
|
781 |
alive = true;
|
|
782 |
} while (true);
|
|
783 |
loopPassTwo = prevLoopPassTwo;
|
|
784 |
inits = initsWhenFalse;
|
|
785 |
uninits = uninitsWhenFalse;
|
|
786 |
alive = alive && !tree.cond.type.isTrue();
|
|
787 |
alive |= resolveBreaks(tree, prevPendingExits);
|
|
788 |
}
|
|
789 |
|
|
790 |
public void visitWhileLoop(JCWhileLoop tree) {
|
|
791 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
792 |
boolean prevLoopPassTwo = loopPassTwo;
|
|
793 |
Bits initsCond;
|
|
794 |
Bits uninitsCond;
|
|
795 |
pendingExits = new ListBuffer<PendingExit>();
|
|
796 |
do {
|
|
797 |
Bits uninitsEntry = uninits.dup();
|
|
798 |
scanCond(tree.cond);
|
|
799 |
initsCond = initsWhenFalse;
|
|
800 |
uninitsCond = uninitsWhenFalse;
|
|
801 |
inits = initsWhenTrue;
|
|
802 |
uninits = uninitsWhenTrue;
|
|
803 |
alive = !tree.cond.type.isFalse();
|
|
804 |
scanStat(tree.body);
|
|
805 |
alive |= resolveContinues(tree);
|
|
806 |
if (log.nerrors != 0 ||
|
|
807 |
loopPassTwo ||
|
|
808 |
uninitsEntry.diffSet(uninits).nextBit(firstadr) == -1)
|
|
809 |
break;
|
|
810 |
uninits = uninitsEntry.andSet(uninits);
|
|
811 |
loopPassTwo = true;
|
|
812 |
alive = true;
|
|
813 |
} while (true);
|
|
814 |
loopPassTwo = prevLoopPassTwo;
|
|
815 |
inits = initsCond;
|
|
816 |
uninits = uninitsCond;
|
|
817 |
alive = resolveBreaks(tree, prevPendingExits) ||
|
|
818 |
!tree.cond.type.isTrue();
|
|
819 |
}
|
|
820 |
|
|
821 |
public void visitForLoop(JCForLoop tree) {
|
|
822 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
823 |
boolean prevLoopPassTwo = loopPassTwo;
|
|
824 |
int nextadrPrev = nextadr;
|
|
825 |
scanStats(tree.init);
|
|
826 |
Bits initsCond;
|
|
827 |
Bits uninitsCond;
|
|
828 |
pendingExits = new ListBuffer<PendingExit>();
|
|
829 |
do {
|
|
830 |
Bits uninitsEntry = uninits.dup();
|
|
831 |
if (tree.cond != null) {
|
|
832 |
scanCond(tree.cond);
|
|
833 |
initsCond = initsWhenFalse;
|
|
834 |
uninitsCond = uninitsWhenFalse;
|
|
835 |
inits = initsWhenTrue;
|
|
836 |
uninits = uninitsWhenTrue;
|
|
837 |
alive = !tree.cond.type.isFalse();
|
|
838 |
} else {
|
|
839 |
initsCond = inits.dup();
|
|
840 |
initsCond.inclRange(firstadr, nextadr);
|
|
841 |
uninitsCond = uninits.dup();
|
|
842 |
uninitsCond.inclRange(firstadr, nextadr);
|
|
843 |
alive = true;
|
|
844 |
}
|
|
845 |
scanStat(tree.body);
|
|
846 |
alive |= resolveContinues(tree);
|
|
847 |
scan(tree.step);
|
|
848 |
if (log.nerrors != 0 ||
|
|
849 |
loopPassTwo ||
|
|
850 |
uninitsEntry.dup().diffSet(uninits).nextBit(firstadr) == -1)
|
|
851 |
break;
|
|
852 |
uninits = uninitsEntry.andSet(uninits);
|
|
853 |
loopPassTwo = true;
|
|
854 |
alive = true;
|
|
855 |
} while (true);
|
|
856 |
loopPassTwo = prevLoopPassTwo;
|
|
857 |
inits = initsCond;
|
|
858 |
uninits = uninitsCond;
|
|
859 |
alive = resolveBreaks(tree, prevPendingExits) ||
|
|
860 |
tree.cond != null && !tree.cond.type.isTrue();
|
|
861 |
nextadr = nextadrPrev;
|
|
862 |
}
|
|
863 |
|
|
864 |
public void visitForeachLoop(JCEnhancedForLoop tree) {
|
|
865 |
visitVarDef(tree.var);
|
|
866 |
|
|
867 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
868 |
boolean prevLoopPassTwo = loopPassTwo;
|
|
869 |
int nextadrPrev = nextadr;
|
|
870 |
scan(tree.expr);
|
|
871 |
Bits initsStart = inits.dup();
|
|
872 |
Bits uninitsStart = uninits.dup();
|
|
873 |
|
|
874 |
letInit(tree.pos(), tree.var.sym);
|
|
875 |
pendingExits = new ListBuffer<PendingExit>();
|
|
876 |
do {
|
|
877 |
Bits uninitsEntry = uninits.dup();
|
|
878 |
scanStat(tree.body);
|
|
879 |
alive |= resolveContinues(tree);
|
|
880 |
if (log.nerrors != 0 ||
|
|
881 |
loopPassTwo ||
|
|
882 |
uninitsEntry.diffSet(uninits).nextBit(firstadr) == -1)
|
|
883 |
break;
|
|
884 |
uninits = uninitsEntry.andSet(uninits);
|
|
885 |
loopPassTwo = true;
|
|
886 |
alive = true;
|
|
887 |
} while (true);
|
|
888 |
loopPassTwo = prevLoopPassTwo;
|
|
889 |
inits = initsStart;
|
|
890 |
uninits = uninitsStart.andSet(uninits);
|
|
891 |
resolveBreaks(tree, prevPendingExits);
|
|
892 |
alive = true;
|
|
893 |
nextadr = nextadrPrev;
|
|
894 |
}
|
|
895 |
|
|
896 |
public void visitLabelled(JCLabeledStatement tree) {
|
|
897 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
898 |
pendingExits = new ListBuffer<PendingExit>();
|
|
899 |
scanStat(tree.body);
|
|
900 |
alive |= resolveBreaks(tree, prevPendingExits);
|
|
901 |
}
|
|
902 |
|
|
903 |
public void visitSwitch(JCSwitch tree) {
|
|
904 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
905 |
pendingExits = new ListBuffer<PendingExit>();
|
|
906 |
int nextadrPrev = nextadr;
|
|
907 |
scanExpr(tree.selector);
|
|
908 |
Bits initsSwitch = inits;
|
|
909 |
Bits uninitsSwitch = uninits.dup();
|
|
910 |
boolean hasDefault = false;
|
|
911 |
for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
|
|
912 |
alive = true;
|
|
913 |
inits = initsSwitch.dup();
|
|
914 |
uninits = uninits.andSet(uninitsSwitch);
|
|
915 |
JCCase c = l.head;
|
|
916 |
if (c.pat == null)
|
|
917 |
hasDefault = true;
|
|
918 |
else
|
|
919 |
scanExpr(c.pat);
|
|
920 |
scanStats(c.stats);
|
|
921 |
addVars(c.stats, initsSwitch, uninitsSwitch);
|
|
922 |
// Warn about fall-through if lint switch fallthrough enabled.
|
|
923 |
if (!loopPassTwo &&
|
|
924 |
alive &&
|
|
925 |
lint.isEnabled(Lint.LintCategory.FALLTHROUGH) &&
|
|
926 |
c.stats.nonEmpty() && l.tail.nonEmpty())
|
|
927 |
log.warning(l.tail.head.pos(),
|
|
928 |
"possible.fall-through.into.case");
|
|
929 |
}
|
|
930 |
if (!hasDefault) {
|
|
931 |
inits.andSet(initsSwitch);
|
|
932 |
alive = true;
|
|
933 |
}
|
|
934 |
alive |= resolveBreaks(tree, prevPendingExits);
|
|
935 |
nextadr = nextadrPrev;
|
|
936 |
}
|
|
937 |
// where
|
|
938 |
/** Add any variables defined in stats to inits and uninits. */
|
|
939 |
private static void addVars(List<JCStatement> stats, Bits inits,
|
|
940 |
Bits uninits) {
|
|
941 |
for (;stats.nonEmpty(); stats = stats.tail) {
|
|
942 |
JCTree stat = stats.head;
|
|
943 |
if (stat.getTag() == JCTree.VARDEF) {
|
|
944 |
int adr = ((JCVariableDecl) stat).sym.adr;
|
|
945 |
inits.excl(adr);
|
|
946 |
uninits.incl(adr);
|
|
947 |
}
|
|
948 |
}
|
|
949 |
}
|
|
950 |
|
|
951 |
public void visitTry(JCTry tree) {
|
|
952 |
List<Type> caughtPrev = caught;
|
|
953 |
List<Type> thrownPrev = thrown;
|
|
954 |
thrown = List.nil();
|
|
955 |
for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail)
|
|
956 |
caught = chk.incl(l.head.param.type, caught);
|
|
957 |
Bits uninitsTryPrev = uninitsTry;
|
|
958 |
ListBuffer<PendingExit> prevPendingExits = pendingExits;
|
|
959 |
pendingExits = new ListBuffer<PendingExit>();
|
|
960 |
Bits initsTry = inits.dup();
|
|
961 |
uninitsTry = uninits.dup();
|
|
962 |
scanStat(tree.body);
|
|
963 |
List<Type> thrownInTry = thrown;
|
|
964 |
thrown = thrownPrev;
|
|
965 |
caught = caughtPrev;
|
|
966 |
boolean aliveEnd = alive;
|
|
967 |
uninitsTry.andSet(uninits);
|
|
968 |
Bits initsEnd = inits;
|
|
969 |
Bits uninitsEnd = uninits;
|
|
970 |
int nextadrCatch = nextadr;
|
|
971 |
|
|
972 |
List<Type> caughtInTry = List.nil();
|
|
973 |
for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
|
|
974 |
alive = true;
|
|
975 |
JCVariableDecl param = l.head.param;
|
|
976 |
Type exc = param.type;
|
|
977 |
if (chk.subset(exc, caughtInTry)) {
|
|
978 |
log.error(l.head.pos(),
|
|
979 |
"except.already.caught", exc);
|
|
980 |
} else if (!chk.isUnchecked(l.head.pos(), exc) &&
|
|
981 |
exc.tsym != syms.throwableType.tsym &&
|
|
982 |
exc.tsym != syms.exceptionType.tsym &&
|
|
983 |
!chk.intersects(exc, thrownInTry)) {
|
|
984 |
log.error(l.head.pos(),
|
|
985 |
"except.never.thrown.in.try", exc);
|
|
986 |
}
|
|
987 |
caughtInTry = chk.incl(exc, caughtInTry);
|
|
988 |
inits = initsTry.dup();
|
|
989 |
uninits = uninitsTry.dup();
|
|
990 |
scan(param);
|
|
991 |
inits.incl(param.sym.adr);
|
|
992 |
uninits.excl(param.sym.adr);
|
|
993 |
scanStat(l.head.body);
|
|
994 |
initsEnd.andSet(inits);
|
|
995 |
uninitsEnd.andSet(uninits);
|
|
996 |
nextadr = nextadrCatch;
|
|
997 |
aliveEnd |= alive;
|
|
998 |
}
|
|
999 |
if (tree.finalizer != null) {
|
|
1000 |
List<Type> savedThrown = thrown;
|
|
1001 |
thrown = List.nil();
|
|
1002 |
inits = initsTry.dup();
|
|
1003 |
uninits = uninitsTry.dup();
|
|
1004 |
ListBuffer<PendingExit> exits = pendingExits;
|
|
1005 |
pendingExits = prevPendingExits;
|
|
1006 |
alive = true;
|
|
1007 |
scanStat(tree.finalizer);
|
|
1008 |
if (!alive) {
|
|
1009 |
// discard exits and exceptions from try and finally
|
|
1010 |
thrown = chk.union(thrown, thrownPrev);
|
|
1011 |
if (!loopPassTwo &&
|
|
1012 |
lint.isEnabled(Lint.LintCategory.FINALLY)) {
|
|
1013 |
log.warning(TreeInfo.diagEndPos(tree.finalizer),
|
|
1014 |
"finally.cannot.complete");
|
|
1015 |
}
|
|
1016 |
} else {
|
|
1017 |
thrown = chk.union(thrown, chk.diff(thrownInTry, caughtInTry));
|
|
1018 |
thrown = chk.union(thrown, savedThrown);
|
|
1019 |
uninits.andSet(uninitsEnd);
|
|
1020 |
// FIX: this doesn't preserve source order of exits in catch
|
|
1021 |
// versus finally!
|
|
1022 |
while (exits.nonEmpty()) {
|
|
1023 |
PendingExit exit = exits.next();
|
|
1024 |
if (exit.inits != null) {
|
|
1025 |
exit.inits.orSet(inits);
|
|
1026 |
exit.uninits.andSet(uninits);
|
|
1027 |
}
|
|
1028 |
pendingExits.append(exit);
|
|
1029 |
}
|
|
1030 |
inits.orSet(initsEnd);
|
|
1031 |
alive = aliveEnd;
|
|
1032 |
}
|
|
1033 |
} else {
|
|
1034 |
thrown = chk.union(thrown, chk.diff(thrownInTry, caughtInTry));
|
|
1035 |
inits = initsEnd;
|
|
1036 |
uninits = uninitsEnd;
|
|
1037 |
alive = aliveEnd;
|
|
1038 |
ListBuffer<PendingExit> exits = pendingExits;
|
|
1039 |
pendingExits = prevPendingExits;
|
|
1040 |
while (exits.nonEmpty()) pendingExits.append(exits.next());
|
|
1041 |
}
|
|
1042 |
uninitsTry.andSet(uninitsTryPrev).andSet(uninits);
|
|
1043 |
}
|
|
1044 |
|
|
1045 |
public void visitConditional(JCConditional tree) {
|
|
1046 |
scanCond(tree.cond);
|
|
1047 |
Bits initsBeforeElse = initsWhenFalse;
|
|
1048 |
Bits uninitsBeforeElse = uninitsWhenFalse;
|
|
1049 |
inits = initsWhenTrue;
|
|
1050 |
uninits = uninitsWhenTrue;
|
|
1051 |
if (tree.truepart.type.tag == BOOLEAN &&
|
|
1052 |
tree.falsepart.type.tag == BOOLEAN) {
|
|
1053 |
// if b and c are boolean valued, then
|
|
1054 |
// v is (un)assigned after a?b:c when true iff
|
|
1055 |
// v is (un)assigned after b when true and
|
|
1056 |
// v is (un)assigned after c when true
|
|
1057 |
scanCond(tree.truepart);
|
|
1058 |
Bits initsAfterThenWhenTrue = initsWhenTrue.dup();
|
|
1059 |
Bits initsAfterThenWhenFalse = initsWhenFalse.dup();
|
|
1060 |
Bits uninitsAfterThenWhenTrue = uninitsWhenTrue.dup();
|
|
1061 |
Bits uninitsAfterThenWhenFalse = uninitsWhenFalse.dup();
|
|
1062 |
inits = initsBeforeElse;
|
|
1063 |
uninits = uninitsBeforeElse;
|
|
1064 |
scanCond(tree.falsepart);
|
|
1065 |
initsWhenTrue.andSet(initsAfterThenWhenTrue);
|
|
1066 |
initsWhenFalse.andSet(initsAfterThenWhenFalse);
|
|
1067 |
uninitsWhenTrue.andSet(uninitsAfterThenWhenTrue);
|
|
1068 |
uninitsWhenFalse.andSet(uninitsAfterThenWhenFalse);
|
|
1069 |
} else {
|
|
1070 |
scanExpr(tree.truepart);
|
|
1071 |
Bits initsAfterThen = inits.dup();
|
|
1072 |
Bits uninitsAfterThen = uninits.dup();
|
|
1073 |
inits = initsBeforeElse;
|
|
1074 |
uninits = uninitsBeforeElse;
|
|
1075 |
scanExpr(tree.falsepart);
|
|
1076 |
inits.andSet(initsAfterThen);
|
|
1077 |
uninits.andSet(uninitsAfterThen);
|
|
1078 |
}
|
|
1079 |
}
|
|
1080 |
|
|
1081 |
public void visitIf(JCIf tree) {
|
|
1082 |
scanCond(tree.cond);
|
|
1083 |
Bits initsBeforeElse = initsWhenFalse;
|
|
1084 |
Bits uninitsBeforeElse = uninitsWhenFalse;
|
|
1085 |
inits = initsWhenTrue;
|
|
1086 |
uninits = uninitsWhenTrue;
|
|
1087 |
scanStat(tree.thenpart);
|
|
1088 |
if (tree.elsepart != null) {
|
|
1089 |
boolean aliveAfterThen = alive;
|
|
1090 |
alive = true;
|
|
1091 |
Bits initsAfterThen = inits.dup();
|
|
1092 |
Bits uninitsAfterThen = uninits.dup();
|
|
1093 |
inits = initsBeforeElse;
|
|
1094 |
uninits = uninitsBeforeElse;
|
|
1095 |
scanStat(tree.elsepart);
|
|
1096 |
inits.andSet(initsAfterThen);
|
|
1097 |
uninits.andSet(uninitsAfterThen);
|
|
1098 |
alive = alive | aliveAfterThen;
|
|
1099 |
} else {
|
|
1100 |
inits.andSet(initsBeforeElse);
|
|
1101 |
uninits.andSet(uninitsBeforeElse);
|
|
1102 |
alive = true;
|
|
1103 |
}
|
|
1104 |
}
|
|
1105 |
|
|
1106 |
|
|
1107 |
|
|
1108 |
public void visitBreak(JCBreak tree) {
|
|
1109 |
recordExit(tree);
|
|
1110 |
}
|
|
1111 |
|
|
1112 |
public void visitContinue(JCContinue tree) {
|
|
1113 |
recordExit(tree);
|
|
1114 |
}
|
|
1115 |
|
|
1116 |
public void visitReturn(JCReturn tree) {
|
|
1117 |
scanExpr(tree.expr);
|
|
1118 |
// if not initial constructor, should markDead instead of recordExit
|
|
1119 |
recordExit(tree);
|
|
1120 |
}
|
|
1121 |
|
|
1122 |
public void visitThrow(JCThrow tree) {
|
|
1123 |
scanExpr(tree.expr);
|
|
1124 |
markThrown(tree, tree.expr.type);
|
|
1125 |
markDead();
|
|
1126 |
}
|
|
1127 |
|
|
1128 |
public void visitApply(JCMethodInvocation tree) {
|
|
1129 |
scanExpr(tree.meth);
|
|
1130 |
scanExprs(tree.args);
|
|
1131 |
for (List<Type> l = tree.meth.type.getThrownTypes(); l.nonEmpty(); l = l.tail)
|
|
1132 |
markThrown(tree, l.head);
|
|
1133 |
}
|
|
1134 |
|
|
1135 |
public void visitNewClass(JCNewClass tree) {
|
|
1136 |
scanExpr(tree.encl);
|
|
1137 |
scanExprs(tree.args);
|
|
1138 |
// scan(tree.def);
|
|
1139 |
for (List<Type> l = tree.constructor.type.getThrownTypes();
|
|
1140 |
l.nonEmpty();
|
|
1141 |
l = l.tail)
|
|
1142 |
markThrown(tree, l.head);
|
|
1143 |
scan(tree.def);
|
|
1144 |
}
|
|
1145 |
|
|
1146 |
public void visitNewArray(JCNewArray tree) {
|
|
1147 |
scanExprs(tree.dims);
|
|
1148 |
scanExprs(tree.elems);
|
|
1149 |
}
|
|
1150 |
|
|
1151 |
public void visitAssert(JCAssert tree) {
|
|
1152 |
Bits initsExit = inits.dup();
|
|
1153 |
Bits uninitsExit = uninits.dup();
|
|
1154 |
scanCond(tree.cond);
|
|
1155 |
uninitsExit.andSet(uninitsWhenTrue);
|
|
1156 |
if (tree.detail != null) {
|
|
1157 |
inits = initsWhenFalse;
|
|
1158 |
uninits = uninitsWhenFalse;
|
|
1159 |
scanExpr(tree.detail);
|
|
1160 |
}
|
|
1161 |
inits = initsExit;
|
|
1162 |
uninits = uninitsExit;
|
|
1163 |
}
|
|
1164 |
|
|
1165 |
public void visitAssign(JCAssign tree) {
|
|
1166 |
JCTree lhs = TreeInfo.skipParens(tree.lhs);
|
|
1167 |
if (!(lhs instanceof JCIdent)) scanExpr(lhs);
|
|
1168 |
scanExpr(tree.rhs);
|
|
1169 |
letInit(lhs);
|
|
1170 |
}
|
|
1171 |
|
|
1172 |
public void visitAssignop(JCAssignOp tree) {
|
|
1173 |
scanExpr(tree.lhs);
|
|
1174 |
scanExpr(tree.rhs);
|
|
1175 |
letInit(tree.lhs);
|
|
1176 |
}
|
|
1177 |
|
|
1178 |
public void visitUnary(JCUnary tree) {
|
|
1179 |
switch (tree.getTag()) {
|
|
1180 |
case JCTree.NOT:
|
|
1181 |
scanCond(tree.arg);
|
|
1182 |
Bits t = initsWhenFalse;
|
|
1183 |
initsWhenFalse = initsWhenTrue;
|
|
1184 |
initsWhenTrue = t;
|
|
1185 |
t = uninitsWhenFalse;
|
|
1186 |
uninitsWhenFalse = uninitsWhenTrue;
|
|
1187 |
uninitsWhenTrue = t;
|
|
1188 |
break;
|
|
1189 |
case JCTree.PREINC: case JCTree.POSTINC:
|
|
1190 |
case JCTree.PREDEC: case JCTree.POSTDEC:
|
|
1191 |
scanExpr(tree.arg);
|
|
1192 |
letInit(tree.arg);
|
|
1193 |
break;
|
|
1194 |
default:
|
|
1195 |
scanExpr(tree.arg);
|
|
1196 |
}
|
|
1197 |
}
|
|
1198 |
|
|
1199 |
public void visitBinary(JCBinary tree) {
|
|
1200 |
switch (tree.getTag()) {
|
|
1201 |
case JCTree.AND:
|
|
1202 |
scanCond(tree.lhs);
|
|
1203 |
Bits initsWhenFalseLeft = initsWhenFalse;
|
|
1204 |
Bits uninitsWhenFalseLeft = uninitsWhenFalse;
|
|
1205 |
inits = initsWhenTrue;
|
|
1206 |
uninits = uninitsWhenTrue;
|
|
1207 |
scanCond(tree.rhs);
|
|
1208 |
initsWhenFalse.andSet(initsWhenFalseLeft);
|
|
1209 |
uninitsWhenFalse.andSet(uninitsWhenFalseLeft);
|
|
1210 |
break;
|
|
1211 |
case JCTree.OR:
|
|
1212 |
scanCond(tree.lhs);
|
|
1213 |
Bits initsWhenTrueLeft = initsWhenTrue;
|
|
1214 |
Bits uninitsWhenTrueLeft = uninitsWhenTrue;
|
|
1215 |
inits = initsWhenFalse;
|
|
1216 |
uninits = uninitsWhenFalse;
|
|
1217 |
scanCond(tree.rhs);
|
|
1218 |
initsWhenTrue.andSet(initsWhenTrueLeft);
|
|
1219 |
uninitsWhenTrue.andSet(uninitsWhenTrueLeft);
|
|
1220 |
break;
|
|
1221 |
default:
|
|
1222 |
scanExpr(tree.lhs);
|
|
1223 |
scanExpr(tree.rhs);
|
|
1224 |
}
|
|
1225 |
}
|
|
1226 |
|
|
1227 |
public void visitIdent(JCIdent tree) {
|
|
1228 |
if (tree.sym.kind == VAR)
|
|
1229 |
checkInit(tree.pos(), (VarSymbol)tree.sym);
|
|
1230 |
}
|
|
1231 |
|
|
1232 |
public void visitTypeCast(JCTypeCast tree) {
|
|
1233 |
super.visitTypeCast(tree);
|
|
1234 |
if (!tree.type.isErroneous()
|
|
1235 |
&& lint.isEnabled(Lint.LintCategory.CAST)
|
|
1236 |
&& types.isSameType(tree.expr.type, tree.clazz.type)) {
|
|
1237 |
log.warning(tree.pos(), "redundant.cast", tree.expr.type);
|
|
1238 |
}
|
|
1239 |
}
|
|
1240 |
|
|
1241 |
public void visitTopLevel(JCCompilationUnit tree) {
|
|
1242 |
// Do nothing for TopLevel since each class is visited individually
|
|
1243 |
}
|
|
1244 |
|
|
1245 |
/**************************************************************************
|
|
1246 |
* main method
|
|
1247 |
*************************************************************************/
|
|
1248 |
|
|
1249 |
/** Perform definite assignment/unassignment analysis on a tree.
|
|
1250 |
*/
|
|
1251 |
public void analyzeTree(JCTree tree, TreeMaker make) {
|
|
1252 |
try {
|
|
1253 |
this.make = make;
|
|
1254 |
inits = new Bits();
|
|
1255 |
uninits = new Bits();
|
|
1256 |
uninitsTry = new Bits();
|
|
1257 |
initsWhenTrue = initsWhenFalse =
|
|
1258 |
uninitsWhenTrue = uninitsWhenFalse = null;
|
|
1259 |
if (vars == null)
|
|
1260 |
vars = new VarSymbol[32];
|
|
1261 |
else
|
|
1262 |
for (int i=0; i<vars.length; i++)
|
|
1263 |
vars[i] = null;
|
|
1264 |
firstadr = 0;
|
|
1265 |
nextadr = 0;
|
|
1266 |
pendingExits = new ListBuffer<PendingExit>();
|
|
1267 |
alive = true;
|
|
1268 |
this.thrown = this.caught = null;
|
|
1269 |
this.classDef = null;
|
|
1270 |
scan(tree);
|
|
1271 |
} finally {
|
|
1272 |
// note that recursive invocations of this method fail hard
|
|
1273 |
inits = uninits = uninitsTry = null;
|
|
1274 |
initsWhenTrue = initsWhenFalse =
|
|
1275 |
uninitsWhenTrue = uninitsWhenFalse = null;
|
|
1276 |
if (vars != null) for (int i=0; i<vars.length; i++)
|
|
1277 |
vars[i] = null;
|
|
1278 |
firstadr = 0;
|
|
1279 |
nextadr = 0;
|
|
1280 |
pendingExits = null;
|
|
1281 |
this.make = null;
|
|
1282 |
this.thrown = this.caught = null;
|
|
1283 |
this.classDef = null;
|
|
1284 |
}
|
|
1285 |
}
|
|
1286 |
}
|