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 public class BytecodePruner {
12 public static final boolean deleteMethods = false;
13 public static SyntheticRepository repo = null;
14 public static HashSet dest = new HashSet();
15 public static String outdir = ".";
16 public static Hashtable subclasses = new Hashtable();
17 public static int level = 0;
19 public BytecodePruner() { }
21 public void loadAllMethods(String classname) throws Exception {
22 visitJavaClass(repo.loadClass(classname));
23 Method[] meths = getMethods(repo.loadClass(classname));
24 for(int i=0; i<meths.length; i++)
25 visitJavaMethod(repo.loadClass(classname), meths[i]);
28 public void loadField(String classAndMethodName) throws Exception {
29 String classname = classAndMethodName.substring(0, classAndMethodName.lastIndexOf('.'));
30 String methodname = classAndMethodName.substring(classAndMethodName.lastIndexOf('.') + 1);
31 visitJavaClass(repo.loadClass(classname));
32 Field[] meths = repo.loadClass(classname).getFields();
33 for(int i=0; i<meths.length; i++)
34 if (meths[i].getName().equals(methodname))
35 visitJavaField(meths[i]);
39 public void loadMethod(String classAndMethodName) throws Exception {
40 String classname = classAndMethodName.substring(0, classAndMethodName.lastIndexOf('.'));
41 String methodname = classAndMethodName.substring(classAndMethodName.lastIndexOf('.') + 1);
42 if (classname.endsWith("." + methodname)) methodname = "<init>";
43 visitJavaClass(repo.loadClass(classname));
44 Method[] meths = getMethods(repo.loadClass(classname));
45 for(int i=0; i<meths.length; i++)
46 if (meths[i].getName().equals(methodname))
47 visitJavaMethod(repo.loadClass(classname), meths[i]);
49 public static void main(String[] s) throws Exception {
51 if (s.length >= 3 && s[1].equals("-o")) { outdir = s[2]; start += 2; }
52 repo = SyntheticRepository.getInstance(new ClassPath(s[0]));
54 BytecodePruner bcp = new BytecodePruner();
55 for(int i=start; i<s.length; i++) {
57 if (s[i].endsWith(".class")) {
58 bcp.visitJavaClass(repo.loadClass(s[i].substring(0, s[i].length() - 6)));
60 JavaClass cl = repo.loadClass(s[i].substring(0, s[i].lastIndexOf('.')));;
61 bcp.visitJavaClass(cl);
64 } catch (Exception e) {
65 System.out.println("WARNING: couldn't load class for " + s[i]);
69 System.out.println("\n\n======================================================================\n");
71 // we call start(), but the VM calls run()...
72 bcp.loadMethod("java.lang.Thread.run");
73 bcp.loadAllMethods("java.lang.SecurityContext");
74 bcp.loadAllMethods("java.lang.ThreadDeath");
76 bcp.loadAllMethods("java.util.Hashtable$HashIterator");
77 bcp.loadMethod("java.util.SimpleTimeZone.useDaylightTime");
78 bcp.visitJavaClass(repo.loadClass("gnu.gcj.runtime.FinalizerThread"));
79 bcp.visitJavaClass(repo.loadClass("gnu.gcj.runtime.FirstThread"));
81 bcp.loadMethod("java.lang.Thread.run"); // we call start(), but the VM calls run()...
82 bcp.loadMethod("java.lang.ref.Reference.enqueue"); // the GC calls this directly
83 bcp.loadAllMethods("gnu.gcj.runtime.StringBuffer"); // the compiler emits calls directly to this class
84 bcp.loadAllMethods("gnu.gcj.convert.Input_UTF8"); // retrieved via reflection
85 bcp.loadAllMethods("gnu.gcj.convert.Output_UTF8"); // retrieved via reflection
87 bcp.loadAllMethods("gnu.gcj.protocol.http.Handler");
88 bcp.loadAllMethods("gnu.gcj.protocol.file.Handler");
89 bcp.loadAllMethods("gnu.gcj.protocol.core.Handler");
90 bcp.loadAllMethods("gnu.gcj.protocol.jar.Handler");
92 // to ensure we get all the stuff that might be called from CNI
93 bcp.loadAllMethods("org.ibex.plat.Linux");
94 bcp.loadAllMethods("org.ibex.plat.X11");
95 bcp.loadAllMethods("org.ibex.Surface");
96 bcp.loadAllMethods("org.ibex.Picture");
97 bcp.loadAllMethods("org.ibex.PixelBuffer");
99 // primary entry point
100 bcp.loadMethod("org.ibex.plat.Linux.main");
101 System.out.println();
103 // FIXME: insert "the null class" when eliminating?
104 System.out.println("Dumping...");
106 StringTokenizer st = new StringTokenizer(s[0], ":");
107 while(st.hasMoreTokens()) {
108 ZipFile zf = new ZipFile(st.nextToken());
109 Enumeration e = zf.entries();
110 while(e.hasMoreElements()) {
111 String ss = ((ZipEntry)e.nextElement()).getName();
112 if (!ss.endsWith(".class")) continue;
113 ss = ss.substring(0, ss.length() - 6);
114 ss = ss.replace('/', '.');
115 dump(repo.loadClass(ss));
120 public static void dump(JavaClass clazz) throws Exception {
121 if (!dest.contains(clazz)) return;
123 ConstantPoolGen newcpg = new ConstantPoolGen(clazz.getConstantPool());
124 ClassGen cg = new ClassGen(clazz);
125 InstructionFactory factory = new InstructionFactory(cg, newcpg);
128 cg.setConstantPool(newcpg);
130 boolean constructed = false;
131 Method[] methods = getMethods(clazz);
132 for(int i=0; i<methods.length; i++)
133 if (dest.contains(methods[i]) && methods[i].getName().equals("<init>"))
136 // we can only prune static fields (to avoid altering object layout, which is hardcoded into
137 // CNI code), but that's okay since instance fields don't contribute to binary size
138 Field[] fields = clazz.getFields();
139 for(int i=0; i<fields.length; i++) {
140 if (!dest.contains(fields[i]) && fields[i].isStatic()) {
141 System.out.println(" pruning field " + clazz.getClassName() + "." + fields[i].getName());
142 cg.removeField(fields[i]);
144 /* -- there's really no point to this --
145 if (!constructed && !fields[i].isStatic()) {
146 System.out.println(" unconstructed: pruning field " + clazz.getClassName() + "." + fields[i].getName());
147 cg.removeField(fields[i]);
153 boolean good = false;
154 for(int i=0; i<methods.length; i++) {
155 if (dest.contains(methods[i]) && (constructed || !methods[i].isStatic())) {
156 if (!methods[i].getName().equals("<clinit>")) good = true;
158 if (methods[i].getCode() == null) {
159 System.out.println(" empty codeblock: " + clazz.getClassName() + "." + methods[i].getName());
161 System.out.println(" pruning " +(constructed?"":"unconstructed")+ " method " +
162 clazz.getClassName() + "." + methods[i].getName());
163 if (deleteMethods) { cg.removeMethod(methods[i]); continue; }
164 MethodGen mg = new MethodGen(methods[i], clazz.getClassName(), newcpg);
165 mg.removeExceptions();
166 InstructionList il = new InstructionList();
167 mg.setInstructionList(il);
168 InstructionHandle ih_0 = il.append(factory.createNew("java.lang.UnsatisfiedLinkError"));
169 il.append(InstructionConstants.DUP);
170 il.append(factory.createInvoke("java.lang.UnsatisfiedLinkError",
171 "<init>", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL));
172 il.append(InstructionConstants.ATHROW);
175 mg.removeExceptions();
176 mg.removeLocalVariables();
177 mg.removeExceptionHandlers();
178 mg.removeLineNumbers();
179 cg.replaceMethod(methods[i], mg.getMethod());
186 System.out.println("DROPPING " + clazz.getClassName());
187 JavaClass[] ifaces = clazz.getInterfaces();
188 String[] ifacestrings = new String[ifaces.length];
189 for(int i=0; i<ifaces.length; i++) ifacestrings[i] = ifaces[i].getClassName();
190 cg = new ClassGen(clazz.getClassName(),
191 clazz.getSuperClass().getClassName(),
193 clazz.getAccessFlags(),
197 System.out.println("dumping " + clazz.getClassName());
199 new File(outdir + "/" + new File(clazz.getClassName().replace('.', '/')).getParent()).mkdirs();
200 cg.getJavaClass().dump(outdir + "/" + clazz.getClassName().replace('.', '/') + ".class");
203 public JavaClass sig2class(String sig) throws Exception {
204 if (sig == null) return null;
205 while (sig.length() > 0 && (sig.charAt(0) == 'L' || sig.charAt(0) == '[')) {
206 if (sig.charAt(0) == 'L') sig = sig.substring(1, sig.length() - 1);
207 else if (sig.charAt(0) == '[') sig = sig.substring(1, sig.length());
209 if (sig.length() <= 1) return null;
210 if (sig.equals("<null object>")) return null;
211 if (sig.startsWith("<return address")) return null;
212 return repo.loadClass(sig);
214 public void load(String sig) throws Exception {
215 if (sig == null) return;
216 while (sig.length() > 0 && (sig.charAt(0) == 'L' || sig.charAt(0) == '[')) {
217 if (sig.charAt(0) == 'L') sig = sig.substring(1, sig.length() - 1);
218 else if (sig.charAt(0) == '[') sig = sig.substring(1, sig.length());
220 if (sig.length() <= 1) return;
221 if (sig.equals("<null object>")) return;
222 if (sig.startsWith("<return address")) return;
223 visitJavaClass(repo.loadClass(sig));
225 public void load(Type t) throws Exception {
226 if (t == null) return;
227 if (t instanceof ArrayType) load(((ArrayType)t).getElementType());
228 if (!(t instanceof ObjectType)) return;
229 load(((ObjectType)t).getClassName());
232 public String getMethodSignature(Method m, ConstantPoolGen cpg) throws Exception { return m.getName() + m.getSignature(); }
233 public String getMethodSignature(InvokeInstruction ii, ConstantPoolGen cpg) throws Exception {
235 Type[] argtypes = ii.getArgumentTypes(cpg);
236 for(int j=0; j<argtypes.length; j++) sig += argtypes[j].getSignature();
237 return ii.getMethodName(cpg) + "(" + sig + ")" + ii.getReturnType(cpg).getSignature();
240 public void visitJavaMethod(JavaClass jc, Method method) throws Exception {
242 if (jc.getClassName().indexOf("SharedLib") != -1) return;
243 if (jc.getClassName().indexOf("Datagram") != -1) return;
245 // gcj bug; gcj can't compile this method from a .class file input; I have no idea why
246 if (jc.getClassName().equals("java.lang.System") && method.getName().equals("runFinalizersOnExit")) return;
248 if (dest.contains(method)) return;
251 for(int i=0; i<level; i++) System.out.print(" ");
252 ConstantPoolGen cpg = new ConstantPoolGen(method.getConstantPool());
253 System.out.println(jc.getClassName() + "." + getMethodSignature(method, cpg));
254 markMethodInSubclasses(jc, method, cpg);
255 if (method.getCode() == null) { level -= 2; return; }
256 byte[] code = method.getCode().getCode();
257 InstructionList il = new InstructionList(code);
258 Instruction[] instructions = il.getInstructions();
259 for(int i=0; i<instructions.length; i++){
260 Instruction instr = instructions[i];
261 if (instr instanceof LoadClass) load(((LoadClass)instr).getLoadClassType(cpg));
262 if (instr instanceof CPInstruction) load(((CPInstruction)instr).getType(cpg));
263 if (instr instanceof TypedInstruction) {
264 try { load(((TypedInstruction)instr).getType(cpg)); } catch (Exception e) { /* DELIBERATE */ }
266 if (instr instanceof NEW) {
267 for(int j=0; j<level; j++) System.out.print(" ");
268 loadMethod(((NEW)instr).getLoadClassType(cpg).getClassName() + ".<init>");
270 if (instr instanceof org.apache.bcel.generic.FieldOrMethod)
271 load(((org.apache.bcel.generic.FieldOrMethod)instr).getClassType(cpg));
272 if (instr instanceof org.apache.bcel.generic.FieldInstruction) {
273 load(((org.apache.bcel.generic.FieldInstruction)instr).getFieldType(cpg));
274 load(((org.apache.bcel.generic.FieldInstruction)instr).getType(cpg));
275 String fieldName = ((org.apache.bcel.generic.FieldInstruction)instr).getFieldName(cpg);
276 JavaClass jc2 = repo.loadClass(((ObjectType)((org.apache.bcel.generic.FieldInstruction)instr).
277 getLoadClassType(cpg)).getClassName());
278 Field[] fields = jc2.getFields();
279 for(int j=0; j<fields.length; j++) if (fields[j].getName().equals(fieldName)) visitJavaField(fields[j]);
281 if (instr instanceof InvokeInstruction) {
282 InvokeInstruction ii = (InvokeInstruction)instr;
283 String ii_sig = getMethodSignature(ii, cpg);
284 JavaClass c = sig2class(ii.getLoadClassType(cpg).getSignature());
286 load(ii.getType(cpg));
287 Method[] meths = getMethods(c);
288 boolean good = false;
289 for(int i2=0; i2<meths.length; i2++) {
290 if (getMethodSignature(meths[i2], cpg).equals(ii_sig)) {
291 visitJavaMethod(c, meths[i2]);
296 if (!good) throw new Exception("couldn't find method " + getMethodSignature(ii, cpg) + " in " + c.getClassName());
301 // FIXME: move this to the top
302 Type[] argtypes = method.getArgumentTypes();
303 for(int i=0; i<argtypes.length; i++) load(argtypes[i]);
304 if (method.getExceptionTable() != null) {
305 String[] exntypes = method.getExceptionTable().getExceptionNames();
306 for(int i=0; i<exntypes.length; i++) load(exntypes[i]);
310 public void visitJavaField(Field field) throws Exception { if (!dest.contains(field)) dest.add(field); }
312 public void visitJavaClass(JavaClass clazz) throws Exception {
313 if (dest.contains(clazz)) return;
316 ConstantPoolGen cpg = new ConstantPoolGen(clazz.getConstantPool());
317 System.out.println(clazz.getClassName() + ".class");
319 JavaClass superclass = clazz.getSuperClass();
320 for(JavaClass sup = superclass; sup != null; sup = sup.getSuperClass()) {
321 if (subclasses.get(sup) == null) subclasses.put(sup, new HashSet());
322 ((HashSet)subclasses.get(sup)).add(clazz);
324 JavaClass[] interfaces = clazz.getAllInterfaces();
325 for(int i=0; i<interfaces.length; i++) {
326 if (subclasses.get(interfaces[i]) == null) subclasses.put(interfaces[i], new HashSet());
327 ((HashSet)subclasses.get(interfaces[i])).add(clazz);
330 for(JavaClass sup = superclass; sup != null; sup = sup.getSuperClass()) {
332 remarkMethods(sup, clazz, cpg);
334 for(int i=0; i<interfaces.length; i++) {
335 visitJavaClass(interfaces[i]);
336 remarkMethods(interfaces[i], clazz, cpg);
339 Method[] methods = getMethods(clazz);
340 for(int i=0; i<methods.length; i++) {
341 if (methods[i].getName().equals("<clinit>")) visitJavaMethod(clazz, methods[i]);
342 if (methods[i].getName().equals("equals")) visitJavaMethod(clazz, methods[i]);
343 if (methods[i].getName().equals("hashCode")) visitJavaMethod(clazz, methods[i]);
344 if (methods[i].getName().equals("finalize")) visitJavaMethod(clazz, methods[i]);
345 if (methods[i].getName().equals("clone")) visitJavaMethod(clazz, methods[i]);
346 if (methods[i].getName().equals("toString")) visitJavaMethod(clazz, methods[i]);
350 public void markMethodInSubclasses(JavaClass c, Method m, JavaClass subclass, ConstantPoolGen cpg) throws Exception {
351 if (m.isStatic()) return;
352 String sig = getMethodSignature(m, cpg);
353 Method[] submethods = getMethods(subclass);
354 for(int j=0; j<submethods.length; j++)
355 if (getMethodSignature(submethods[j], cpg).equals(sig))
356 visitJavaMethod(subclass, submethods[j]);
358 public void markMethodInSubclasses(JavaClass c, Method m, ConstantPoolGen cpg) throws Exception {
359 if (m.isStatic()) return;
360 HashSet s = (HashSet)subclasses.get(c);
361 if (s == null) return;
362 Object[] subclasses = s.toArray();
363 for(int i=0; i<subclasses.length; i++) {
364 JavaClass subclass = (JavaClass)subclasses[i];
365 if (subclass == c) continue;
366 markMethodInSubclasses(c, m, subclass, cpg);
370 public void remarkMethods(JavaClass c, ConstantPoolGen cpg) throws Exception {
371 Method[] meths =getMethods(c);
372 for(int j=0; j<meths.length; j++) if (dest.contains(meths[j])) markMethodInSubclasses(c, meths[j], cpg);
375 public void remarkMethods(JavaClass c, JavaClass target, ConstantPoolGen cpg) throws Exception {
376 Method[] meths = getMethods(c);
377 for(int j=0; j<meths.length; j++) if (dest.contains(meths[j])) markMethodInSubclasses(c, meths[j], target, cpg);
380 public static Hashtable methodsHashtable = new Hashtable();
381 public static Method[] getMethods(JavaClass c) {
382 Method[] ret = (Method[])methodsHashtable.get(c);
383 if (ret == null) methodsHashtable.put(c, ret = c.getMethods());