0N/A/*
1879N/A * Copyright (c) 1995, 2003, Oracle and/or its affiliates. All rights reserved.
0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
0N/A *
0N/A * This code is free software; you can redistribute it and/or modify it
0N/A * under the terms of the GNU General Public License version 2 only, as
0N/A * published by the Free Software Foundation. Oracle designates this
0N/A * particular file as subject to the "Classpath" exception as provided
0N/A * by Oracle in the LICENSE file that accompanied this code.
0N/A *
0N/A * This code is distributed in the hope that it will be useful, but WITHOUT
0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
0N/A * version 2 for more details (a copy is included in the LICENSE file that
0N/A * accompanied this code).
0N/A *
0N/A * You should have received a copy of the GNU General Public License version
0N/A * 2 along with this work; if not, write to the Free Software Foundation,
1472N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1472N/A *
1472N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
0N/A * or visit www.oracle.com if you need additional information or have any
0N/A * questions.
1879N/A */
1879N/A
1879N/Apackage sun.tools.asm;
1879N/A
0N/Aimport sun.tools.java.*;
0N/Aimport java.io.IOException;
0N/Aimport java.io.DataOutputStream;
0N/A
0N/A/**
0N/A * This class is used to assemble the local variable table.
0N/A *
0N/A * WARNING: The contents of this source file are not part of any
0N/A * supported API. Code that depends on them does so at its own risk:
0N/A * they are subject to change or removal without notice.
0N/A *
0N/A * @author Arthur van Hoff
0N/A */
0N/Afinal
0N/Aclass LocalVariableTable {
0N/A LocalVariable locals[] = new LocalVariable[8];
0N/A int len;
0N/A
0N/A /**
0N/A * Define a new local variable. Merge entries where possible.
0N/A */
0N/A void define(MemberDefinition field, int slot, int from, int to) {
0N/A if (from >= to) {
0N/A return;
0N/A }
0N/A for (int i = 0 ; i < len ; i++) {
0N/A if ((locals[i].field == field) && (locals[i].slot == slot) &&
0N/A (from <= locals[i].to) && (to >= locals[i].from)) {
0N/A locals[i].from = Math.min(locals[i].from, from);
0N/A locals[i].to = Math.max(locals[i].to, to);
0N/A return;
0N/A }
0N/A }
0N/A if (len == locals.length) {
0N/A LocalVariable newlocals[] = new LocalVariable[len * 2];
0N/A System.arraycopy(locals, 0, newlocals, 0, len);
0N/A locals = newlocals;
0N/A }
0N/A locals[len++] = new LocalVariable(field, slot, from, to);
0N/A }
0N/A
0N/A /**
0N/A * Trim overlapping local ranges. Java forbids shadowing of
0N/A * locals in nested scopes, but non-nested scopes may still declare
0N/A * locals with the same name. Because local variable ranges are
0N/A * computed using flow analysis as part of assembly, it isn't
0N/A * possible to simply make sure variable ranges end where the
0N/A * enclosing lexical scope ends. This method makes sure that
0N/A * variables with the same name don't overlap, giving priority to
0N/A * fields with higher slot numbers that should have appeared later
0N/A * in the source.
0N/A */
0N/A private void trim_ranges() {
0N/A for (int i=0; i<len; i++) {
0N/A for (int j=i+1; j<len; j++) {
0N/A if ((locals[i].field.getName()==locals[j].field.getName())
0N/A && (locals[i].from <= locals[j].to)
0N/A && (locals[i].to >= locals[j].from)) {
0N/A // At this point we know that both ranges are
0N/A // the same name and there is also overlap or they abut
1879N/A if (locals[i].slot < locals[j].slot) {
1879N/A if (locals[i].from < locals[j].from) {
locals[i].to = Math.min(locals[i].to, locals[j].from);
} else {
// We've detected two local variables with the
// same name, and the one with the greater slot
// number starts before the other. This order
// reversal may happen with locals with the same
// name declared in both a try body and an
// associated catch clause. This is rare, and
// we give up.
}
} else if (locals[i].slot > locals[j].slot) {
if (locals[i].from > locals[j].from) {
locals[j].to = Math.min(locals[j].to, locals[i].from);
} else {
// Same situation as above; just give up.
}
} else {
// This case can happen if there are two variables
// with the same name and slot numbers, and ranges
// that abut. AFAIK the only way this can occur
// is with multiple static initializers. Punt.
}
}
}
}
}
/**
* Write out the data.
*/
void write(Environment env, DataOutputStream out, ConstantPool tab) throws IOException {
trim_ranges();
out.writeShort(len);
for (int i = 0 ; i < len ; i++) {
//System.out.println("pc=" + locals[i].from + ", len=" + (locals[i].to - locals[i].from) + ", nm=" + locals[i].field.getName() + ", slot=" + locals[i].slot);
out.writeShort(locals[i].from);
out.writeShort(locals[i].to - locals[i].from);
out.writeShort(tab.index(locals[i].field.getName().toString()));
out.writeShort(tab.index(locals[i].field.getType().getTypeSignature()));
out.writeShort(locals[i].slot);
}
}
}