/***
* ASM Guide
* Copyright (c) 2007 Eric Bruneton
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package ch7.sec2;
import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
import static org.objectweb.asm.Opcodes.ACONST_NULL;
import static org.objectweb.asm.Opcodes.ALOAD;
import static org.objectweb.asm.Opcodes.ASTORE;
import static org.objectweb.asm.Opcodes.ATHROW;
import static org.objectweb.asm.Opcodes.DUP;
import static org.objectweb.asm.Opcodes.GETFIELD;
import static org.objectweb.asm.Opcodes.GOTO;
import static org.objectweb.asm.Opcodes.IADD;
import static org.objectweb.asm.Opcodes.ICONST_1;
import static org.objectweb.asm.Opcodes.IFEQ;
import static org.objectweb.asm.Opcodes.ILOAD;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL;
import static org.objectweb.asm.Opcodes.MONITORENTER;
import static org.objectweb.asm.Opcodes.MONITOREXIT;
import static org.objectweb.asm.Opcodes.NEW;
import static org.objectweb.asm.Opcodes.PUTFIELD;
import static org.objectweb.asm.Opcodes.RETURN;
import java.util.List;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.analysis.AnalyzerException;
import util.AbstractTestCase;
/**
* ASM Guide example test class.
*
* @author Eric Bruneton
*/
public class NullDereferenceAnalyzerTest extends AbstractTestCase {
public void test() throws Exception {
MethodNode mn = new MethodNode(ACC_PUBLIC, "m", "(ZZ)V", null, null);
mn.visitCode();
Label l0 = new Label();
Label l1 = new Label();
Label l2 = new Label();
Label l3 = new Label();
Label l4 = new Label();
Label l5 = new Label();
Label l6 = new Label();
mn.visitTryCatchBlock(l0, l1, l2, null);
mn.visitTryCatchBlock(l2, l3, l2, null);
mn.visitInsn(ACONST_NULL); // insn 0
mn.visitVarInsn(ASTORE, 3);
mn.visitInsn(ACONST_NULL); // insn 2
mn.visitVarInsn(ASTORE, 4);
mn.visitTypeInsn(NEW, "C");
mn.visitInsn(DUP);
mn.visitMethodInsn(INVOKESPECIAL, "C", "<init>", "()V");
mn.visitVarInsn(ASTORE, 5);
mn.visitVarInsn(ILOAD, 1);
mn.visitJumpInsn(IFEQ, l4);
mn.visitTypeInsn(NEW, "java/lang/Integer"); // insn
// 10
mn.visitInsn(DUP);
mn.visitInsn(ICONST_1);
mn.visitMethodInsn(INVOKESPECIAL, "java/lang/Integer", "<init>",
"(I)V");
mn.visitVarInsn(ASTORE, 3);
mn.visitTypeInsn(NEW, "C"); // insn 15
mn.visitInsn(DUP);
mn.visitMethodInsn(INVOKESPECIAL, "C", "<init>", "()V");
mn.visitVarInsn(ASTORE, 4);
mn.visitLabel(l4);
mn.visitVarInsn(ILOAD, 2);
mn.visitJumpInsn(IFEQ, l5);
mn.visitTypeInsn(NEW, "java/lang/Integer"); // insn
// 22
mn.visitInsn(DUP);
mn.visitInsn(ICONST_1);
mn.visitMethodInsn(INVOKESPECIAL, "java/lang/Integer", "<init>",
"(I)V");
mn.visitVarInsn(ASTORE, 3);
mn.visitTypeInsn(NEW, "C"); // insn 27
mn.visitInsn(DUP);
mn.visitMethodInsn(INVOKESPECIAL, "C", "<init>", "()V");
mn.visitVarInsn(ASTORE, 4);
mn.visitLabel(l5);
mn.visitVarInsn(ALOAD, 4);
mn.visitInsn(DUP);
mn.visitVarInsn(ASTORE, 6);
mn.visitInsn(MONITORENTER); // insn 35
mn.visitLabel(l0);
mn.visitVarInsn(ALOAD, 4);
mn.visitVarInsn(ALOAD, 4);
mn.visitFieldInsn(GETFIELD, "C", "i", "I"); // insn
// 39
mn.visitVarInsn(ALOAD, 5);
mn.visitFieldInsn(GETFIELD, "C", "i", "I");
mn.visitInsn(IADD);
mn.visitVarInsn(ALOAD, 3);
mn.visitMethodInsn(INVOKEVIRTUAL, // insn 44
"java/lang/Integer", "intValue", "()I");
mn.visitInsn(IADD);
mn.visitFieldInsn(PUTFIELD, "C", "i", "I"); // insn
// 46
mn.visitVarInsn(ALOAD, 6);
mn.visitInsn(MONITOREXIT); // insn 48
mn.visitLabel(l1);
mn.visitJumpInsn(GOTO, l6);
mn.visitLabel(l2);
mn.visitVarInsn(ALOAD, 6);
mn.visitInsn(MONITOREXIT); // insn 53
mn.visitLabel(l3);
mn.visitInsn(ATHROW);
mn.visitLabel(l6);
mn.visitInsn(RETURN);
mn.visitMaxs(3, 7);
mn.visitEnd();
List<AbstractInsnNode> occurences;
occurences = new NullDereferenceAnalyzer().findNullDereferences(
"D", mn);
assertEquals(6, occurences.size());
assertTrue(occurences.contains(mn.instructions.get(35)));
assertTrue(occurences.contains(mn.instructions.get(39)));
assertTrue(occurences.contains(mn.instructions.get(44)));
assertTrue(occurences.contains(mn.instructions.get(46)));
assertTrue(occurences.contains(mn.instructions.get(48)));
assertTrue(occurences.contains(mn.instructions.get(53)));
}
@Override
protected ClassVisitor getClassAdapter(final ClassVisitor cv) {
return new ClassNode() {
@Override
public void visitEnd() {
for (MethodNode mn : (List<MethodNode>) methods) {
try {
new NullDereferenceAnalyzer()
.findNullDereferences(name, mn);
} catch (AnalyzerException e) {
}
}
accept(cv);
}
};
}
// source code used to get above ASMified code
public void m(boolean a, boolean b) {
Integer i = null;
C c = null;
C d = new C();
if (a) {
i = new Integer(1);
c = new C();
}
if (b) {
i = new Integer(1);
c = new C();
}
synchronized (c) { // c may be null
c.i = c.i + d.i + i.intValue(); // c and i may
// be null, but
// not d
}
}
static class C {
int i;
}
}