4 import java.util.zip.*;
5 import org.apache.bcel.*;
6 import org.apache.bcel.generic.*;
7 import org.apache.bcel.classfile.*;
8 import org.apache.bcel.util.*;
10 // Reachability rules:
12 // - a constructor is reachable iff it is called
13 // - a static method is reachable iff it is called
14 // - a nonstatic method is reachable
15 // - a static field is reachable iff it is referenced
16 // - a nonstatic field is reachable iff it is referenced
17 // - <clinit> is reachable iff any methods, static methods, fields, or constructors are reachable
19 // - if a method is reachable, all the methods it overrides are reachable
21 // try eliminating instance methods/fields if no ctor is reachable...
22 // distinguish between overloaded forms of a given method
23 // slim down the set of loadAllMethod() classes
26 // FIXME: nonstatic method invocation or field access implies that object will be constructed (ie hint)
28 public class BytecodePruner {
30 public static final boolean deleteMethods = false;
33 public static SyntheticRepository repo = null;
35 public static HashSet dest = new HashSet();
37 public static String outdir = ".";
39 public void loadAllMethods(String classname) throws Exception {
40 visitJavaClass(repo.loadClass(classname));
41 Method[] meths = getMethods(repo.loadClass(classname));
42 for(int i=0; i<meths.length; i++) visitJavaMethod(repo.loadClass(classname), meths[i]);
44 public void loadMethod(String classAndMethodName) throws Exception {
45 String classname = classAndMethodName.substring(0, classAndMethodName.lastIndexOf('.'));
46 String methodname = classAndMethodName.substring(classAndMethodName.lastIndexOf('.') + 1);
47 visitJavaClass(repo.loadClass(classname));
48 Method[] meths = getMethods(repo.loadClass(classname));
49 for(int i=0; i<meths.length; i++)
50 if (meths[i].getName().equals(methodname))
51 visitJavaMethod(repo.loadClass(classname), meths[i]);
53 public static void main(String[] s) throws Exception {
55 if (s.length >= 3 && s[1].equals("-o")) { outdir = s[2]; start += 2; }
56 repo = SyntheticRepository.getInstance(new ClassPath(s[0]));
57 BytecodePruner bcp = new BytecodePruner();
59 for(int i=start; i<s.length; i++) {
61 if (s[i].endsWith(".class")) {
62 bcp.visitJavaClass(repo.loadClass(s[i].substring(0, s[i].length() - 6)));
64 JavaClass cl = repo.loadClass(s[i].substring(0, s[i].lastIndexOf('.')));;
65 bcp.visitJavaClass(cl);
66 Method[] meths = getMethods(cl);
67 for(int j=0; j<meths.length; j++) {
68 if (meths[j].getName().equals(s[i].substring(s[i].lastIndexOf('.') + 1)))
69 bcp.visitJavaMethod(cl, meths[j]);
72 } catch (Exception e) {
73 System.out.println("WARNING: couldn't load class for " + s[i]);
76 System.out.println("\n\n======================================================================\n");
78 // we call start(), but the VM calls run()...
79 bcp.loadMethod("java.lang.Thread.run");
80 bcp.loadMethod("java.util.IdentityHashMap.put");
82 bcp.loadAllMethods("java.lang.SecurityContext");
83 bcp.visitJavaClass(repo.loadClass("java.awt.AWTPermission"));
84 bcp.loadAllMethods("java.lang.Throwable");
85 bcp.loadAllMethods("java.io.PrintStream");
86 bcp.loadAllMethods("java.util.PropertyPermission");
87 bcp.loadAllMethods("java.lang.ThreadDeath");
88 bcp.loadAllMethods("gnu.gcj.runtime.StringBuffer");
89 bcp.loadAllMethods("java.security.cert.Certificate");
90 bcp.loadAllMethods("java.security.cert.CertificateEncodingException");
92 bcp.loadMethod("java.util.SimpleTimeZone.useDaylightTime");
93 bcp.loadMethod("java.util.TimeZone.getAvailableIDs");
94 bcp.loadMethod("java.util.TimeZone.getDefaultTimeZoneId");
95 bcp.loadMethod("java.util.Collections$SynchronizedIterator.hasNext");
96 bcp.loadAllMethods("java.util.Hashtable$HashIterator");
97 bcp.loadAllMethods("gnu.gcj.runtime.VMClassLoader");
99 bcp.visitJavaClass(repo.loadClass("java.util.Stack"));
100 bcp.visitJavaClass(repo.loadClass("gnu.classpath.Configuration"));
101 bcp.visitJavaClass(repo.loadClass("gnu.gcj.runtime.JNIWeakRef"));
103 bcp.visitJavaClass(repo.loadClass("gnu.gcj.protocol.http.Handler"));
104 bcp.visitJavaClass(repo.loadClass("gnu.gcj.protocol.file.Handler"));
105 bcp.visitJavaClass(repo.loadClass("gnu.gcj.protocol.jar.Handler"));
106 bcp.visitJavaClass(repo.loadClass("gnu.gcj.protocol.core.Handler"));
107 bcp.visitJavaClass(repo.loadClass("gnu.gcj.runtime.FinalizerThread"));
108 bcp.visitJavaClass(repo.loadClass("gnu.gcj.runtime.FirstThread"));
110 // SecurityManager hacks to avoid java.security?
111 // URL and all descendents? Probably impossible.
112 // ObjectInput/ObjectOutput? Serialization?
114 // often called from native subclasses....
115 bcp.loadAllMethods("org.ibex.Surface");
116 bcp.loadAllMethods("org.ibex.Template$TemplateHelper$1");
117 bcp.loadAllMethods("org.ibex.Surface$DoubleBufferedSurface");
118 bcp.loadAllMethods("org.ibex.Surface$3");
119 bcp.loadAllMethods("org.ibex.Surface$2");
120 bcp.loadAllMethods("org.ibex.Picture");
121 bcp.loadAllMethods("org.ibex.PixelBuffer");
122 bcp.loadAllMethods("org.ibex.Platform");
123 bcp.loadAllMethods("org.ibex.Scheduler");
124 bcp.loadAllMethods("org.ibex.plat.X11");
125 bcp.loadAllMethods("org.ibex.plat.X11$X11Picture");
126 bcp.loadAllMethods("org.ibex.plat.X11$X11PixelBuffer");
127 bcp.loadAllMethods("org.ibex.plat.X11$X11Surface");
128 bcp.loadAllMethods("org.ibex.XMLRPC");
130 bcp.loadAllMethods("java.util.Date");
131 bcp.loadAllMethods("java.text.DateFormat");
132 bcp.loadAllMethods("java.text.NumberFormat");
135 Method[] meths = getMethods(repo.loadClass("org.ibex.plat.Linux"));
136 for(int i=0; i<meths.length; i++) {
137 if (meths[i].getName().equals("main"))
138 bcp.visitJavaMethod(repo.loadClass("org.ibex.plat.Linux"), meths[i]);
140 System.out.println();
142 System.out.println("Dumping...");
144 StringTokenizer st = new StringTokenizer(s[0], ":");
145 while(st.hasMoreTokens()) {
146 ZipFile zf = new ZipFile(st.nextToken());
147 Enumeration e = zf.entries();
148 while(e.hasMoreElements()) {
149 String ss = ((ZipEntry)e.nextElement()).getName();
150 if (!ss.endsWith(".class")) continue;
151 ss = ss.substring(0, ss.length() - 6);
152 ss = ss.replace('/', '.');
153 dump(repo.loadClass(ss));
158 public BytecodePruner() { }
160 public static void dump(JavaClass clazz) throws Exception {
161 if (clazz.getClassName().startsWith("java.sql.")) return;
162 if (!dest.contains(clazz)) return;
164 ConstantPoolGen newcpg = new ConstantPoolGen(clazz.getConstantPool());
165 ClassGen cg = new ClassGen(clazz);
166 InstructionFactory factory = new InstructionFactory(cg, newcpg);
169 cg.setConstantPool(newcpg);
170 Field[] fields = clazz.getFields();
172 for(int i=0; i<fields.length; i++)
173 if (!dest.contains(fields[i]) && false) {
174 System.out.println(" pruning " + clazz.getClassName() + "." + fields[i].getName());
178 // superprune: URLClassLoader, convert.In/Output other than needed, unneeded locales
179 // reflective metadata is killing us...
181 Method[] methods = getMethods(clazz);
183 boolean good = false;
184 for(int i=0; i<methods.length; i++)
185 if (clazz.getClassName().startsWith("gnu.gcj.runtime.")
186 || clazz.getClassName().startsWith("java.io.FileDescriptor")
187 || clazz.getClassName().startsWith("org.ibex.")
188 || clazz.getClassName().startsWith("java.lang.")) {
190 } else if (dest.contains(methods[i])) {
191 if (!methods[i].getName().equals("<clinit>")) good = true;
193 if (methods[i].getCode() == null) {
194 System.out.println(" empty codeblock: " + clazz.getClassName() + "." + methods[i].getName());
196 System.out.println(" pruning " + clazz.getClassName() + "." + methods[i].getName());
197 if (!deleteMethods) {
198 MethodGen mg = new MethodGen(methods[i], clazz.getClassName(), newcpg);
199 mg.removeExceptions();
200 InstructionList il = new InstructionList();
201 mg.setInstructionList(il);
203 InstructionHandle ih_0 = il.append(factory.createNew("java.lang.UnsatisfiedLinkError"));
204 il.append(InstructionConstants.DUP);
205 il.append(factory.createInvoke("java.lang.UnsatisfiedLinkError",
206 "<init>", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL));
207 il.append(InstructionConstants.ATHROW);
211 mg.removeExceptions();
212 mg.removeLocalVariables();
213 mg.removeExceptionHandlers();
214 mg.removeLineNumbers();
216 cg.replaceMethod(methods[i], mg.getMethod());
219 cg.removeMethod(methods[i]);
223 if ((clazz.getClassName().startsWith("gnu.java.locale.LocaleInformation") &&
224 !clazz.getClassName().endsWith("LocaleInformation_en") &&
225 !clazz.getClassName().endsWith("LocaleInformation") &&
226 !clazz.getClassName().endsWith("LocaleInformation_en_US"))
228 ((clazz.getClassName().startsWith("gnu.gcj.convert.Input_") ||
229 clazz.getClassName().startsWith("gnu.gcj.convert.Output_")) &&
230 !(clazz.getClassName().endsWith("ASCII") ||
231 clazz.getClassName().endsWith("UTF8") ||
232 clazz.getClassName().endsWith("iconv") ||
233 clazz.getClassName().endsWith("8859_1")))
236 !clazz.isInterface() &&
237 !clazz.isAbstract() &&
238 !clazz.getClassName().startsWith("java.io.") &&
239 !clazz.getClassName().startsWith("java.lang.") &&
240 !clazz.getClassName().startsWith("gnu.") &&
241 !clazz.getClassName().endsWith("Error") &&
242 !clazz.getClassName().endsWith("Exception") &&
243 !clazz.getClassName().endsWith("Permission"))) {
245 //System.out.println("DROPPING " + clazz.getClassName());
248 new File(outdir + "/" + new File(clazz.getClassName().replace('.', '/')).getParent()).mkdirs();
249 System.out.println("dumping " + clazz.getClassName());
250 cg.getJavaClass().dump(outdir + "/" + clazz.getClassName().replace('.', '/') + ".class");
253 public JavaClass sig2class(String sig) throws Exception {
254 if (sig == null) return null;
255 while (sig.length() > 0 && (sig.charAt(0) == 'L' || sig.charAt(0) == '[')) {
256 if (sig.charAt(0) == 'L') sig = sig.substring(1, sig.length() - 1);
257 else if (sig.charAt(0) == '[') sig = sig.substring(1, sig.length());
259 if (sig.length() <= 1) return null;
260 if (sig.equals("<null object>")) return null;
261 if (sig.startsWith("<return address")) return null;
262 return repo.loadClass(sig);
264 public void load(String sig) throws Exception {
265 if (sig == null) return;
266 while (sig.length() > 0 && (sig.charAt(0) == 'L' || sig.charAt(0) == '[')) {
267 if (sig.charAt(0) == 'L') sig = sig.substring(1, sig.length() - 1);
268 else if (sig.charAt(0) == '[') sig = sig.substring(1, sig.length());
270 if (sig.length() <= 1) return;
271 if (sig.equals("<null object>")) return;
272 if (sig.startsWith("<return address")) return;
273 visitJavaClass(repo.loadClass(sig));
275 public void load(Type t) throws Exception {
276 if (t == null) return;
277 //String sig = t.getSignature();
278 if (t instanceof ArrayType) load(((ArrayType)t).getElementType());
279 if (!(t instanceof ObjectType)) return;
280 load(((ObjectType)t).getClassName());
283 // hashtable of hashsets
284 public static Hashtable subclasses = new Hashtable();
286 public String getMethodSignature(Method m, ConstantPoolGen cpg) throws Exception {
287 return m.getName() + m.getSignature();
290 public String getMethodSignature(InvokeInstruction ii, ConstantPoolGen cpg) throws Exception {
292 Type[] argtypes = ii.getArgumentTypes(cpg);
293 for(int j=0; j<argtypes.length; j++) sig += argtypes[j].getSignature();
294 return ii.getMethodName(cpg) + "(" + sig + ")" + ii.getReturnType(cpg).getSignature();
297 public static int level = 0;
298 public void visitJavaMethod(JavaClass jc, Method method) throws Exception {
300 if (jc.getClassName().equals("java.util.Date") && method.getName().equals("readObject")) return;
301 //if (jc.getClassName().equals("java.net.URLClassLoader")) return;
302 if (jc.getClassName().indexOf("SharedLib") != -1) return;
303 if (jc.getClassName().indexOf("Datagram") != -1) return;
304 if (dest.contains(method)) return;
307 for(int i=0; i<level; i++) System.out.print(" ");
308 ConstantPoolGen cpg = new ConstantPoolGen(method.getConstantPool());
309 System.out.println(jc.getClassName() + "." + getMethodSignature(method, cpg));
310 markMethodInSubclasses(jc, method, cpg);
311 if (method.getCode() == null) { level -= 2; return; }
312 byte[] code = method.getCode().getCode();
313 InstructionList il = new InstructionList(code);
314 Instruction[] instructions = il.getInstructions();
315 for(int i=0; i<instructions.length; i++){
316 Instruction instr = instructions[i];
317 if (instr instanceof LoadClass) load(((LoadClass)instr).getLoadClassType(cpg));
318 if (instr instanceof CPInstruction) load(((CPInstruction)instr).getType(cpg));
319 if (instr instanceof InvokeInstruction) {
320 InvokeInstruction ii = (InvokeInstruction)instr;
321 String ii_sig = getMethodSignature(ii, cpg);
322 JavaClass c = sig2class(ii.getLoadClassType(cpg).getSignature());
323 load(ii.getReturnType(cpg));
324 load(ii.getType(cpg));
325 Method[] meths = getMethods(c);
326 boolean good = false;
327 for(int i2=0; i2<meths.length; i2++) {
328 if (getMethodSignature(meths[i2], cpg).equals(ii_sig)) {
329 visitJavaMethod(c, meths[i2]);
334 if (!good) throw new Exception("couldn't find method " + getMethodSignature(ii, cpg) + " in " + c.getClassName());
338 load(method.getReturnType());
339 Type[] argtypes = method.getArgumentTypes();
340 for(int i=0; i<argtypes.length; i++) load(argtypes[i]);
341 if (method.getExceptionTable() != null) {
342 String[] exntypes = method.getExceptionTable().getExceptionNames();
343 for(int i=0; i<exntypes.length; i++) load(exntypes[i]);
347 public void visitJavaField(Field field) throws Exception {
348 if (dest.contains(field)) return;
350 load(field.getType());
353 public void visitJavaClass(JavaClass clazz) throws Exception {
355 if (clazz.getClassName().startsWith("java.security.") &&
356 !clazz.getClassName().equals("java.security.cert.Certificate")) return;
358 if (dest.contains(clazz)) return;
361 ConstantPoolGen cpg = new ConstantPoolGen(clazz.getConstantPool());
362 String name = clazz.getClassName();
363 System.out.println(clazz.getClassName() + ".class");
365 JavaClass superclass = clazz.getSuperClass();
366 JavaClass[] interfaces = clazz.getAllInterfaces();
367 for(JavaClass sup = superclass; sup != null; sup = sup.getSuperClass()) {
368 if (subclasses.get(sup) == null) subclasses.put(sup, new HashSet());
369 ((HashSet)subclasses.get(sup)).add(clazz);
371 for(int i=0; i<interfaces.length; i++) {
372 if (subclasses.get(interfaces[i]) == null) subclasses.put(interfaces[i], new HashSet());
373 ((HashSet)subclasses.get(interfaces[i])).add(clazz);
376 for(JavaClass sup = superclass; sup != null; sup = sup.getSuperClass()) {
378 remarkMethods(sup, clazz, cpg);
380 for(int i=0; i<interfaces.length; i++) {
381 visitJavaClass(interfaces[i]);
382 remarkMethods(interfaces[i], clazz, cpg);
385 Field[] fields = clazz.getFields();
386 Method[] methods = getMethods(clazz);
387 for(int i=0; i<fields.length; i++) visitJavaField(fields[i]);
388 for(int i=0; i<methods.length; i++) {
389 if (methods[i].getName().equals("<clinit>")) visitJavaMethod(clazz, methods[i]);
391 // only if ctor reachable (?)
392 if (methods[i].getName().equals("equals")) visitJavaMethod(clazz, methods[i]);
393 if (methods[i].getName().equals("hashCode")) visitJavaMethod(clazz, methods[i]);
394 if (methods[i].getName().equals("finalize")) visitJavaMethod(clazz, methods[i]);
395 if (methods[i].getName().equals("clone")) visitJavaMethod(clazz, methods[i]);
396 if (methods[i].getName().equals("toString")) visitJavaMethod(clazz, methods[i]);
400 public void markMethodInSubclasses(JavaClass c, Method m, JavaClass subclass, ConstantPoolGen cpg) throws Exception {
401 if (m.isStatic()) return;
402 String sig = getMethodSignature(m, cpg);
403 Method[] submethods = getMethods(subclass);
404 for(int j=0; j<submethods.length; j++)
405 if (getMethodSignature(submethods[j], cpg).equals(sig))
406 visitJavaMethod(subclass, submethods[j]);
408 public void markMethodInSubclasses(JavaClass c, Method m, ConstantPoolGen cpg) throws Exception {
409 if (m.isStatic()) return;
410 HashSet s = (HashSet)subclasses.get(c);
411 if (s == null) return;
412 Object[] subclasses = s.toArray();
413 for(int i=0; i<subclasses.length; i++) {
414 JavaClass subclass = (JavaClass)subclasses[i];
415 for(int j=0; j<level; j++) System.out.print(" ");
416 System.out.println(" [subclass " + subclass.getClassName() + "]");
417 if (subclass == c) return;
418 markMethodInSubclasses(c, m, subclass, cpg);
422 public void remarkMethods(JavaClass c, ConstantPoolGen cpg) throws Exception {
423 Method[] meths =getMethods(c);
424 for(int j=0; j<meths.length; j++) if (dest.contains(meths[j])) markMethodInSubclasses(c, meths[j], cpg);
427 public void remarkMethods(JavaClass c, JavaClass target, ConstantPoolGen cpg) throws Exception {
428 Method[] meths = getMethods(c);
429 for(int j=0; j<meths.length; j++) if (dest.contains(meths[j])) markMethodInSubclasses(c, meths[j], target, cpg);
432 public static Hashtable methodsHashtable = new Hashtable();
433 public static Method[] getMethods(JavaClass c) {
434 Method[] ret = (Method[])methodsHashtable.get(c);
435 if (ret == null) methodsHashtable.put(c, ret = c.getMethods());