/*
* Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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*/
package sun.tools.tree;
import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import sun.tools.asm.TryData;
import sun.tools.asm.CatchData;
import java.io.PrintStream;
import java.util.Enumeration;
import java.util.Hashtable;
/**
* WARNING: The contents of this source file are not part of any
* supported API. Code that depends on them does so at its own risk:
* they are subject to change or removal without notice.
*/
public
class TryStatement extends Statement {
Statement body;
Statement args[];
long arrayCloneWhere; // private note posted from MethodExpression
/**
* Constructor
*/
public TryStatement(long where, Statement body, Statement args[]) {
super(TRY, where);
this.body = body;
this.args = args;
}
/**
* Check statement
*/
Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
checkLabel(env, ctx);
try {
vset = reach(env, vset);
Hashtable newexp = new Hashtable();
CheckContext newctx = new CheckContext(ctx, this);
// Check 'try' block. A variable is DA (DU) before the try
// block if it is DA (DU) before the try statement.
Vset vs = body.check(env, newctx, vset.copy(), newexp);
// A variable is DA before a catch block if it is DA before the
// try statement. A variable is DU before a catch block if it
// is DU after the try block and before any 'break', 'continue',
// 'throw', or 'return' contained therein. That is, the variable
// is DU upon entry to the try-statement and is not assigned to
// anywhere within the try block.
Vset cvs = Vset.firstDAandSecondDU(vset, vs.copy().join(newctx.vsTryExit));
for (int i = 0 ; i < args.length ; i++) {
// A variable is DA (DU) after a try statement if
// it is DA (DU) after every catch block.
vs = vs.join(args[i].check(env, newctx, cvs.copy(), exp));
}
// Check that catch statements are actually reached
for (int i = 1 ; i < args.length ; i++) {
CatchStatement cs = (CatchStatement)args[i];
if (cs.field == null) {
continue;
}
Type type = cs.field.getType();
ClassDefinition def = env.getClassDefinition(type);
for (int j = 0 ; j < i ; j++) {
CatchStatement cs2 = (CatchStatement)args[j];
if (cs2.field == null) {
continue;
}
Type t = cs2.field.getType();
ClassDeclaration c = env.getClassDeclaration(t);
if (def.subClassOf(env, c)) {
env.error(args[i].where, "catch.not.reached");
break;
}
}
}
ClassDeclaration ignore1 = env.getClassDeclaration(idJavaLangError);
ClassDeclaration ignore2 = env.getClassDeclaration(idJavaLangRuntimeException);
// Make sure the exception is actually throw in that part of the code
for (int i = 0 ; i < args.length ; i++) {
CatchStatement cs = (CatchStatement)args[i];
if (cs.field == null) {
continue;
}
Type type = cs.field.getType();
if (!type.isType(TC_CLASS)) {
// CatchStatement.checkValue() will have already printed
// an error message
continue;
}
ClassDefinition def = env.getClassDefinition(type);
// Anyone can throw these!
if (def.subClassOf(env, ignore1) || def.superClassOf(env, ignore1) ||
def.subClassOf(env, ignore2) || def.superClassOf(env, ignore2)) {
continue;
}
// Make sure the exception is actually throw in that part of the code
boolean ok = false;
for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
ClassDeclaration c = (ClassDeclaration)e.nextElement();
if (def.superClassOf(env, c) || def.subClassOf(env, c)) {
ok = true;
break;
}
}
if (!ok && arrayCloneWhere != 0
&& def.getName().toString().equals("java.lang.CloneNotSupportedException")) {
env.error(arrayCloneWhere, "warn.array.clone.supported", def.getName());
}
if (!ok) {
env.error(cs.where, "catch.not.thrown", def.getName());
}
}
// Only carry over exceptions that are not caught
for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
ClassDeclaration c = (ClassDeclaration)e.nextElement();
ClassDefinition def = c.getClassDefinition(env);
boolean add = true;
for (int i = 0 ; i < args.length ; i++) {
CatchStatement cs = (CatchStatement)args[i];
if (cs.field == null) {
continue;
}
Type type = cs.field.getType();
if (type.isType(TC_ERROR))
continue;
if (def.subClassOf(env, env.getClassDeclaration(type))) {
add = false;
break;
}
}
if (add) {
exp.put(c, newexp.get(c));
}
}
// A variable is DA (DU) after a try statement if it is DA (DU)
// after the try block and after every catch block. These variables
// are represented by 'vs'. If the try statement is labelled, we
// may also exit from it (including from within a catch block) via
// a break statement.
// If there is a finally block, the Vset returned here is further
// adjusted. Note that this 'TryStatement' node will be a child of
// a 'FinallyStatement' node in that case.
return ctx.removeAdditionalVars(vs.join(newctx.vsBreak));
} catch (ClassNotFound e) {
env.error(where, "class.not.found", e.name, opNames[op]);
return vset;
}
}
/**
* Inline
*/
public Statement inline(Environment env, Context ctx) {
if (body != null) {
body = body.inline(env, new Context(ctx, this));
}
if (body == null) {
return null;
}
for (int i = 0 ; i < args.length ; i++) {
if (args[i] != null) {
args[i] = args[i].inline(env, new Context(ctx, this));
}
}
return (args.length == 0) ? eliminate(env, body) : this;
}
/**
* Create a copy of the statement for method inlining
*/
public Statement copyInline(Context ctx, boolean valNeeded) {
TryStatement s = (TryStatement)clone();
if (body != null) {
s.body = body.copyInline(ctx, valNeeded);
}
s.args = new Statement[args.length];
for (int i = 0 ; i < args.length ; i++) {
if (args[i] != null) {
s.args[i] = args[i].copyInline(ctx, valNeeded);
}
}
return s;
}
/**
* Compute cost of inlining this statement
*/
public int costInline(int thresh, Environment env, Context ctx){
// Don't inline methods containing try statements.
// If the try statement is being inlined in order to
// inline a method that returns a value which is
// a subexpression of an expression involving the
// operand stack, then the early operands may get lost.
// This shows up as a verifier error. For example,
// in the following:
//
// public static int test() {
// try { return 2; } catch (Exception e) { return 0; }
// }
//
// System.out.println(test());
//
// an inlined call to test() might look like this:
//
// 0 getstatic <Field java.io.PrintStream out>
// 3 iconst_2
// 4 goto 9
// 7 pop
// 8 iconst_0
// 9 invokevirtual <Method void println(int)>
// 12 return
// Exception table:
// from to target type
// 3 7 7 <Class java.lang.Exception>
//
// This fails to verify because the operand stored
// for System.out gets axed at an exception, leading to
// an inconsistent stack depth at pc=7.
//
// Note that although all code must be able to be inlined
// to implement initializers, this problem doesn't come up,
// as try statements themselves can never be expressions.
// It suffices here to make sure they are never inlined as part
// of optimization.
return thresh;
}
/**
* Code
*/
public void code(Environment env, Context ctx, Assembler asm) {
CodeContext newctx = new CodeContext(ctx, this);
TryData td = new TryData();
for (int i = 0 ; i < args.length ; i++) {
Type t = ((CatchStatement)args[i]).field.getType();
if (t.isType(TC_CLASS)) {
td.add(env.getClassDeclaration(t));
} else {
td.add(t);
}
}
asm.add(where, opc_try, td);
if (body != null) {
body.code(env, newctx, asm);
}
asm.add(td.getEndLabel());
asm.add(where, opc_goto, newctx.breakLabel);
for (int i = 0 ; i < args.length ; i++) {
CatchData cd = td.getCatch(i);
asm.add(cd.getLabel());
args[i].code(env, newctx, asm);
asm.add(where, opc_goto, newctx.breakLabel);
}
asm.add(newctx.breakLabel);
}
/**
* Print
*/
public void print(PrintStream out, int indent) {
super.print(out, indent);
out.print("try ");
if (body != null) {
body.print(out, indent);
} else {
out.print("<empty>");
}
for (int i = 0 ; i < args.length ; i++) {
out.print(" ");
args[i].print(out, indent);
}
}
}