1 cananian 1.1.2.1 // MethodSplitter.java, created Thu Oct 5 15:48:13 2000 by cananian
2 cananian 1.1.2.1 // Copyright (C) 2000 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.Analysis.Transformation;
5 cananian 1.1.2.1
6 cananian 1.1.2.10 import harpoon.Analysis.ClassHierarchy;
7 cananian 1.1.2.11 import harpoon.Backend.Maps.FinalMap;
8 cananian 1.1.2.5 import harpoon.ClassFile.CachingCodeFactory;
9 cananian 1.1.2.5 import harpoon.ClassFile.DuplicateMemberException;
10 cananian 1.1.2.5 import harpoon.ClassFile.HClass;
11 cananian 1.1.2.5 import harpoon.ClassFile.HClassMutator;
12 cananian 1.1.2.5 import harpoon.ClassFile.HCode;
13 cananian 1.1.2.5 import harpoon.ClassFile.HCodeAndMaps;
14 cananian 1.1.2.5 import harpoon.ClassFile.HCodeFactory;
15 cananian 1.1.2.10 import harpoon.ClassFile.HConstructor;
16 cananian 1.1.2.5 import harpoon.ClassFile.HMethod;
17 cananian 1.1.2.7 import harpoon.ClassFile.SerializableCodeFactory;
18 cananian 1.7 import net.cscott.jutil.Default;
19 cananian 1.1.2.5 import harpoon.Util.Util;
20 cananian 1.7 import net.cscott.jutil.WorkSet;
21 cananian 1.1.2.1
22 cananian 1.1.2.10 import java.lang.reflect.Modifier;
23 cananian 1.1.2.5 import java.util.HashMap;
24 cananian 1.1.2.13 import java.util.Iterator;
25 cananian 1.1.2.9 import java.util.List;
26 cananian 1.1.2.5 import java.util.Map;
27 cananian 1.1.2.1 /**
28 cananian 1.1.2.1 * <code>MethodSplitter</code> makes it easier to implement
29 cananian 1.1.2.1 * transformations which specialize methods for one purpose or
30 cananian 1.1.2.2 * another. It is meant to be subclassed. In your subclass,
31 cananian 1.1.2.2 * you will likely want to create a few static fields of type
32 cananian 1.1.2.2 * <code>MethodSplitter.Token</code> to name your specialized
33 cananian 1.1.2.2 * versions, override the <code>isValidToken()</code> method
34 cananian 1.1.2.2 * to include your new tokens, and override
35 cananian 1.1.2.2 * <code>mutateDescriptor()</code> and/or <code>mutateHCode()</code>
36 cananian 1.1.2.2 * to effect the specialization.
37 cananian 1.1.2.7 * <p>
38 cananian 1.1.2.7 * Note that if you mutate the <code>ORIGINAL</code> version of
39 cananian 1.1.2.7 * a method, all split versions will inherit the mutation.
40 cananian 1.1.2.7 * Be careful not to introduce cycles because of this ordering.
41 cananian 1.1.2.1 *
42 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
43 cananian 1.7 * @version $Id: MethodSplitter.java,v 1.7 2004/02/08 01:54:24 cananian Exp $
44 cananian 1.1.2.1 */
45 cananian 1.1.2.16 public abstract class MethodSplitter implements java.io.Serializable {
46 cananian 1.1.2.2 /** The <code>ORIGINAL</code> token represents the original pre-split
47 cananian 1.1.2.2 * version of a method. */
48 cananian 1.1.2.16 public static final Token ORIGINAL = new Token(null) {
49 cananian 1.1.2.16 public Object readResolve() { return ORIGINAL; }
50 cananian 1.1.2.16 public String toString() { return "TOKEN<ORIGINAL>"; }
51 cananian 1.1.2.16 };
52 cananian 1.1.2.2 /** This is the code factory which contains the representations of the
53 cananian 1.1.2.2 * new split methods. */
54 cananian 1.1.2.2 private final CachingCodeFactory hcf;
55 cananian 1.1.2.10 /** This is a class hierarchy, needed to properly split virtual methods.
56 cananian 1.1.2.10 * (Virtual methods have to be also split in all subclasses, in order
57 cananian 1.1.2.10 * for dynamic dispatch to work correctly.) */
58 cananian 1.1.2.10 private final ClassHierarchy ch;
59 cananian 1.1.2.11 /** This is the FinalMap used in the implementation of isVirtual(). */
60 cananian 1.1.2.11 private final FinalMap fm;
61 cananian 1.1.2.2
62 cananian 1.1.2.2 /** Creates a <code>MethodSplitter</code>, based on the method
63 cananian 1.1.2.2 * representations in the <code>parent</code> <code>HCodeFactory</code>.
64 cananian 1.1.2.18 * @param mutateOriginalBeforeSplit if <code>true</code>, the
65 cananian 1.1.2.18 * <i>mutated</i> version of the original is cloned and given
66 cananian 1.1.2.18 * to <code>mutateHCode</code> as source for a split methods;
67 cananian 1.1.2.18 * otherwise, the <i>unmutated</i> version of the original is
68 cananian 1.1.2.18 * taken as the source for the split method. If it doesn't
69 cananian 1.1.2.18 * matter, choose <code>true</code>, as this reduces the
70 cananian 1.1.2.18 * memory footprint.
71 cananian 1.1.2.2 */
72 cananian 1.1.2.22 public MethodSplitter(final HCodeFactory _parent, ClassHierarchy ch,
73 cananian 1.1.2.18 final boolean mutateOriginalBeforeSplit) {
74 cananian 1.1.2.18 final Map origcache = //this is cache for unmutated version
75 cananian 1.1.2.18 mutateOriginalBeforeSplit ? null : new HashMap();
76 cananian 1.1.2.7 this.hcf = new CachingCodeFactory(new SerializableCodeFactory() {
77 cananian 1.1.2.19 public String getCodeName() {
78 cananian 1.1.2.22 return mutateCodeName(_parent.getCodeName());
79 cananian 1.1.2.19 }
80 cananian 1.1.2.22 public void clear(HMethod m) { _parent.clear(m); }
81 cananian 1.1.2.7 public HCode convert(HMethod m) {
82 cananian 1.1.2.9 List swpair = (List) split2orig.get(m);
83 cananian 1.1.2.9 Token tok = (swpair==null) ? ORIGINAL : (Token) swpair.get(1);
84 cananian 1.6
85 cananian 1.6 // For !mutateOriginalBeforeSplit, always do ORIGINAL before
86 cananian 1.6 // split. [Karen found this bug.]
87 cananian 1.6 if (!mutateOriginalBeforeSplit && tok!=ORIGINAL)
88 cananian 1.6 MethodSplitter.this.hcf.convert( (HMethod)swpair.get(0) );
89 cananian 1.6
90 cananian 1.1.2.22 HCode hc = (tok==ORIGINAL) ? _parent.convert(m) :
91 cananian 1.1.2.22 // get unmutated version from cache...
92 cananian 1.1.2.22 (origcache!=null) ? (HCode)origcache.get( swpair.get(0) ) :
93 cananian 1.1.2.17 hcf.convert( (HMethod)swpair.get(0) );
94 cananian 1.1.2.22 // put unmutated version in cache
95 cananian 1.1.2.22 if (origcache!=null && tok==ORIGINAL)
96 cananian 1.1.2.22 origcache.put(m, hc);
97 cananian 1.1.2.7 try {
98 cananian 1.1.2.20 if (hc!=null) hc = mutateHCode(cloneHCode(hc, m), tok);
99 cananian 1.1.2.7 } catch (CloneNotSupportedException ex) {
100 cananian 1.3.2.1 assert false : ("cloning HCode failed: "+ex);
101 cananian 1.1.2.7 }
102 cananian 1.1.2.7 return hc;
103 cananian 1.1.2.18 }
104 cananian 1.1.2.18 }, true/* save cache */) {
105 cananian 1.1.2.18 public void clear(HMethod m) {
106 cananian 1.1.2.22 // this version leaks some methods, but it is safe.
107 cananian 1.1.2.22 if (select(m, ORIGINAL).equals(m) &&
108 cananian 1.1.2.22 (origcache==null || !origcache.containsKey(m)))
109 cananian 1.1.2.22 parent.clear(m);
110 cananian 1.1.2.22 else
111 cananian 1.1.2.22 super.clear(m);
112 cananian 1.1.2.22 /*
113 cananian 1.1.2.22 //XXX: this doesn't work because we can clear original
114 cananian 1.1.2.22 //method before all its mutated children are created.
115 cananian 1.1.2.18 // top cache responsible for origcache too.
116 cananian 1.1.2.18 super.clear(m);
117 cananian 1.1.2.18 if (origcache!=null) origcache.remove(m);
118 cananian 1.1.2.22 */
119 cananian 1.1.2.18 }
120 cananian 1.1.2.18 };
121 cananian 1.1.2.10 this.ch = ch;
122 cananian 1.1.2.12 this.fm = new harpoon.Backend.Maps.CHFinalMap(ch);
123 cananian 1.1.2.1 }
124 cananian 1.1.2.1
125 cananian 1.1.2.9 /** Maps split methods to <original method, token> pairs. */
126 cananian 1.1.2.1 private final Map split2orig = new HashMap();
127 cananian 1.1.2.1 /** Maps <original method, token> pairs to created split methods. */
128 cananian 1.1.2.1 private final Map versions = new HashMap();
129 cananian 1.1.2.1
130 cananian 1.1.2.1 /** Go from a (possibly already split) method to the version of the
131 cananian 1.1.2.2 * method named by the token <code>which</code>. */
132 cananian 1.1.2.1 public final synchronized HMethod select(HMethod source, Token which) {
133 cananian 1.3.2.1 assert isValidToken(which) : "token is not valid";
134 cananian 1.1.2.1 HMethod orig = split2orig.containsKey(source) ?
135 cananian 1.1.2.9 (HMethod) ((List)split2orig.get(source)).get(0) : source;
136 cananian 1.1.2.1 if (which == ORIGINAL) return orig;
137 cananian 1.3.2.1 assert which.suffix!=null : "Null token suffixes are not allowed!";
138 cananian 1.1.2.15 List swpair = Default.pair(orig, which);
139 cananian 1.1.2.9 HMethod splitM = (HMethod) versions.get(swpair);
140 cananian 1.1.2.1 if (splitM == null) {
141 cananian 1.1.2.1 HClassMutator hcm = orig.getDeclaringClass().getMutator();
142 cananian 1.3.2.1 assert hcm!=null : "You're using a linker, not a relinker: "+orig+" "+orig.getDeclaringClass().getLinker();
143 cananian 1.1.2.1 String mname = orig.getName()+"$$"+which.suffix;
144 cananian 1.1.2.1 String mdesc = mutateDescriptor(orig, which);
145 cananian 1.1.2.4 try {
146 cananian 1.1.2.4 splitM = hcm.addDeclaredMethod(mname, mdesc);
147 cananian 1.1.2.4 } catch (DuplicateMemberException dme) {
148 cananian 1.1.2.4 // we can't rename the method, because then inheritance
149 cananian 1.1.2.4 // would not work correctly.
150 cananian 1.3.2.1 assert false : "Can't create method "+mname+mdesc+" in "+
151 cananian 1.1.2.4 orig.getDeclaringClass()+" because it already "+
152 cananian 1.3.2.1 "exists";
153 cananian 1.1.2.1 }
154 cananian 1.1.2.8 splitM.getMutator().setModifiers(orig.getModifiers());
155 cananian 1.1.2.8 splitM.getMutator().setSynthetic(orig.isSynthetic());
156 cananian 1.1.2.21 // XXX: we currently can't add "renamed" constructors, so
157 cananian 1.1.2.21 // if we're splitting a constructor make it private to
158 cananian 1.1.2.21 // ensure that it is non-virtual.
159 cananian 1.1.2.21 if (orig instanceof HConstructor)
160 cananian 1.1.2.21 splitM.getMutator().addModifiers(Modifier.PRIVATE);
161 cananian 1.1.2.1 /* now add this to known versions */
162 cananian 1.1.2.9 versions.put(swpair, splitM);
163 cananian 1.1.2.9 split2orig.put(splitM, swpair);
164 cananian 1.1.2.10 /* now split all subclasses */
165 cananian 1.1.2.13 if (isVirtual(orig)) //only keep splitting if orig is inheritable
166 cananian 1.1.2.13 for (Iterator it=ch.overrides(orig).iterator(); it.hasNext(); )
167 cananian 1.1.2.13 // XXX: a little conservative, since select() will then
168 cananian 1.1.2.13 // turn around and split all the child's children.
169 cananian 1.1.2.13 // ch.overrides(orig, ..., true) would give more accurate
170 cananian 1.1.2.13 // results.
171 cananian 1.1.2.13 select((HMethod)it.next(), which);
172 cananian 1.1.2.9 /* done */
173 cananian 1.1.2.1 }
174 cananian 1.1.2.1 return splitM;
175 cananian 1.1.2.1 }
176 cananian 1.1.2.10 /** Utility method to determine whether a method is inheritable (and
177 cananian 1.1.2.10 * thus it's children should be split whenever it is). */
178 cananian 1.1.2.11 protected boolean isVirtual(HMethod m) {
179 cananian 1.1.2.10 if (m.isStatic()) return false;
180 cananian 1.1.2.10 if (Modifier.isPrivate(m.getModifiers())) return false;
181 cananian 1.1.2.10 if (m instanceof HConstructor) return false;
182 cananian 1.5 if (!m.getDeclaringClass().isArray())
183 cananian 1.5 // XXX arrays are somewhat misleadingly classified as 'final'
184 cananian 1.5 // even though we provide for inheritance of clone() methods
185 cananian 1.5 // and such between array classes. =(
186 cananian 1.5 // (this is the fruit of the strange discrepancies in array
187 cananian 1.5 // inheritance. does A[] derive from Object[] or from Object?)
188 cananian 1.5 if (fm.isFinal(m)) return false;
189 cananian 1.1.2.10 return true;
190 cananian 1.1.2.10 }
191 cananian 1.1.2.10
192 cananian 1.1.2.2 /** Returns a <code>HCodeFactory</code> containing representations for
193 cananian 1.1.2.2 * the methods split by the <code>MethodSplitter</code>. */
194 cananian 1.1.2.12 public HCodeFactory codeFactory() { return hcf; }
195 cananian 1.1.2.1
196 cananian 1.1.2.1 /** Override this method if you want to create mutated methods
197 cananian 1.1.2.1 * with descriptors differing from that of the original method.
198 cananian 1.1.2.1 */
199 cananian 1.1.2.1 protected String mutateDescriptor(HMethod hm, Token which) {
200 cananian 1.1.2.1 return hm.getDescriptor();
201 cananian 1.1.2.1 }
202 cananian 1.1.2.2 /** Override this method to effect transformations on split
203 cananian 1.1.2.2 * methods. */
204 cananian 1.1.2.3 protected HCode mutateHCode(HCodeAndMaps input, Token which) {
205 cananian 1.1.2.3 return input.hcode();
206 cananian 1.1.2.19 }
207 cananian 1.1.2.19 /** Override this method to change the codename which this
208 cananian 1.1.2.19 * <code>MethodMutator</code>'s codefactory reports. */
209 cananian 1.1.2.19 protected String mutateCodeName(String codeName) {
210 cananian 1.1.2.19 return codeName;
211 cananian 1.1.2.20 }
212 cananian 1.1.2.20 /** Override this method if you do not want the mutatable HCode to be
213 cananian 1.1.2.20 * a straight clone of the original HCode: for example, if the
214 cananian 1.1.2.20 * input HCodes were <code>QuadSSI</code> and you wanted to
215 cananian 1.1.2.20 * clone them into <code>QuadRSSI</code>s before mutating.
216 cananian 1.1.2.20 * By default, this method returns <code>hc.clone(newmethod)</code>. */
217 cananian 1.1.2.20 protected HCodeAndMaps cloneHCode(HCode hc, HMethod newmethod)
218 cananian 1.1.2.20 throws CloneNotSupportedException {
219 cananian 1.1.2.20 return hc.clone(newmethod);
220 cananian 1.1.2.2 }
221 cananian 1.1.2.2
222 cananian 1.1.2.1 /** Check the validity of a given <code>MethodSplitter.Token</code>.
223 cananian 1.1.2.1 * Override if (when) your subclass defines new tokens. */
224 cananian 1.1.2.1 protected boolean isValidToken(Token which) {
225 cananian 1.1.2.1 return which==ORIGINAL;
226 cananian 1.1.2.1 }
227 cananian 1.1.2.1
228 cananian 1.1.2.2 /** Subclasses of <code>MethodSplitter</code> refer to "versions"
229 cananian 1.1.2.2 * of the underlying method which may be named by creating
230 cananian 1.1.2.1 * static instances of this <code>MethodSplitter.Token</code>
231 cananian 1.1.2.1 * class. The argument to the constructor specifies a default
232 cananian 1.1.2.2 * suffix for the newly-split method's name. Don't forget
233 cananian 1.1.2.2 * to extend <code>MethodSplitter.isValidToken()</code> to
234 cananian 1.1.2.16 * include your new <code>MethodSplitter.Token</code> subclasses.
235 cananian 1.1.2.16 * <p>
236 cananian 1.1.2.16 * A typical subclass of <code>MethodSplitter</code> will include
237 cananian 1.1.2.16 * the following code fragment:<p>
238 cananian 1.1.2.16 * <pre>
239 cananian 1.1.2.16 * public class FooBlah extends <code>MethodSplitter</code> {
240 cananian 1.1.2.16 * /** Token for the foo-blah version of a method. *<b></b>/
241 cananian 1.1.2.16 * public static final Token FOOBLAH = new Token("fooblah") {
242 cananian 1.1.2.16 * /** This ensures that FOOBLAH is a singleton object. *<b></b>/
243 cananian 1.1.2.16 * public Object readResolve() { return FOOBLAH; }
244 cananian 1.1.2.16 * };
245 cananian 1.1.2.16 * /** Checks the token types handled by this
246 cananian 1.1.2.16 * * <code>MethodSplitter</code> subclass. *<b></b>/
247 cananian 1.1.2.16 * protected boolean isValidToken(Token which) {
248 cananian 1.1.2.16 * return which==FOOBLAH || super.isValidToken(which);
249 cananian 1.1.2.16 * };
250 cananian 1.1.2.16 * };
251 cananian 1.1.2.16 * </pre>
252 cananian 1.1.2.16 */
253 cananian 1.1.2.16 protected abstract static class Token implements java.io.Serializable {
254 cananian 1.1.2.1 final String suffix;
255 cananian 1.1.2.16 /** Create a token, specifying the suggested method suffix. */
256 cananian 1.1.2.16 protected Token(String suggestedSuffix) {
257 cananian 1.1.2.1 this.suffix = suggestedSuffix;
258 cananian 1.1.2.1 }
259 cananian 1.1.2.16 /** This method must be overridden to ensure that <code>Token</code>s
260 cananian 1.1.2.16 * are still singletons after deserialization. See the template
261 cananian 1.1.2.16 * in the class description above. */
262 cananian 1.1.2.16 protected abstract Object readResolve();
263 cananian 1.1.2.16 /** Returns a human-readable representation of this token. */
264 cananian 1.1.2.16 public String toString() { return "TOKEN["+suffix+"]"; }
265 cananian 1.1.2.1 }
266 cananian 1.2 }