|
1
24
25 package org.aspectj.compiler.base.ast;
26
27 import org.aspectj.compiler.base.*;
28
29 import org.aspectj.compiler.base.AssignmentCheckerPass;
30 import org.aspectj.compiler.base.JavaCompiler;
31 import org.aspectj.compiler.base.CodeWriter;
32 import org.aspectj.compiler.base.cst.*;
33
34 import org.aspectj.compiler.base.bcg.CodeBuilder;
35 import org.aspectj.compiler.base.bcg.Label;
36
37 import java.util.HashSet  ;
38 import java.util.Arrays ;
39
40
45 public class SwitchStmt extends Stmt {
46
47 public boolean isBreakable() { return true; }
48
49
52 public void walkFlow(FlowCheckerPass w) {
53 SwitchClauses c = getClauses();
54 w.process(getExpr());
55 FlowCheckerPass.Vars v = w.getVars();
56
57 for (int i = 0, len = c.size(); i < len; i++) {
58 v = findTopLevelVars(v, c.get(i).getStmts());
59 }
60 w.setVars(v);
61 w.enterContext(this);
62 boolean hasDefault = false;
63 for (int i = 0, len = c.size(); i < len; i++) {
64 if (c.get(i).getLabel() == null) { hasDefault = true; }
65 w.setLive(true);
66 w.setVars(v.join(w.getVars()));
67 w.process(c.get(i));
68 w.setVars(w.getVars());
69 }
70 w.leaveContext();
71 if (!hasDefault) w.setVars(w.getVars().join(v));
72
73 FlowCheckerPass.Vars bv = w.getBreakVars(this);
74
75 w.setLive(w.isLive() || ! hasDefault || w.isBroken(this));
76 w.setVars(w.getVars().join(bv));
77 }
78
79 private FlowCheckerPass.Vars findTopLevelVars(FlowCheckerPass.Vars v, Stmts ss) {
80 for (int i = 0, len = ss.size(); i < len; i++) {
81 Stmt s = ss.get(i);
82 if (s instanceof VarDec) {
83 v = v.addUnassigned((VarDec) s);
84 } else if (s instanceof Decs) {
85 v = findTopLevelVars(v, (Decs) s);
86 }
87 }
88 return v;
89 }
90
91 private FlowCheckerPass.Vars findTopLevelVars(FlowCheckerPass.Vars v, Decs ds) {
92 for (int i = 0, len = ds.size(); i < len; i++) {
93 Dec d = ds.get(i);
94 if (d instanceof VarDec) {
95 v = v.addUnassigned((VarDec) d);
96 }
97 }
98 return v;
99 }
100
101 public void preScope(ScopeWalker walker) { walker.pushBlock(); }
103 public ASTObject postScope(ScopeWalker walker) { walker.popBlock(); return this; }
104
105 public void checkSpec() {
106 Type exprType = expr.getType();
107 if (! (exprType instanceof IntishType)) {
108 expr.showTypeError(exprType, getTypeManager().intType);
109 }
110 boolean hasDefault = false;
111 HashSet seenLabels = new HashSet ();
112
113 for (int i = 0, len = clauses.size(); i < len; i++) {
114 SwitchClause c = clauses.get(i);
115 Expr label = c.getLabel();
116 if (label == null) {
117 if (hasDefault) {
118 c.showError("duplicate default label");
119 } else {
120 hasDefault = true;
121 }
122 } else {
123 if (label instanceof LiteralExpr) {
124 if (!label.isAssignableTo(exprType)) {
125 label.showTypeError(label.getType(), exprType);
126 } else {
127 if (label instanceof IntLiteralExpr) {
128 Integer intObj =
129 new Integer (((IntLiteralExpr)label).getIntValue());
130 if (seenLabels.contains(intObj)) {
131 label.showError("duplicate label");
132 } else {
133 seenLabels.add(intObj);
134 }
135 } else {
136 label.showError("expected int constant");
137 }
138 }
139 } else {
140 label.showError("constant expression required");
141 }
142 }
143 }
144 }
145
146 public void unparse(CodeWriter writer) {
147 writer.writeKeyword("switch");
148 writer.requiredSpace();
149 writer.parenExpr(expr);
150 writer.openBlock();
151 writer.writeChildren(clauses);
152 writer.closeBlock();
153 }
154
155
158 public void walkCleanup(ByteCodeCleanupPass w) {
159 SwitchClauses c = getClauses();
160 w.enterContext(this);
161 boolean hasDefault = false;
162 for (int i = 0, len = c.size(); i < len; i++) {
163 if (c.get(i).getLabel() == null) { hasDefault = true; }
164 w.setLive(true);
165 c.get(i).getStmts().walkCleanup(w);
166 }
167 w.leaveContext();
168 w.setLive(w.isLive() || ! hasDefault || w.isBroken(this));
169 }
170
171
174 protected void cgStmt(CodeBuilder cb) {
175 class Pair implements Comparable {
176 int i;
177 Label l;
178 Pair(int i, Label l) { this.i = i; this.l = l; }
179 public int compareTo(Object o) {
180 int other = ((Pair)o).i;
181
182 return (i > other) ? 1 : (i == other) ? 0 : -1;
183 }
184 public String toString() {
185 return "<" + i + ", " + "l" + ">";
186 }
187 }
188
189 Label endLab = cb.genLabel();
190 Label defaultLab = endLab;
191
192 final int len = getClauses().size();
193
194 boolean hasCases = false;
196 Pair[] table = new Pair[len];
197 Label[] clauseStarts = new Label[len];
198 int ti = 0;
199 for (int i = 0; i < len; i++ ) {
200 SwitchClause clause = getClauses().get(i);
201 IntLiteralExpr caseLabel = (IntLiteralExpr) clause.getLabel();
202 Label caseCodeLabel = cb.genLabel();
203 clauseStarts[i] = caseCodeLabel;
204 if (caseLabel == null) {
205 defaultLab = caseCodeLabel;
206 } else {
207 hasCases = true;
208 table[ti++] = new Pair(caseLabel.getIntValue(), caseCodeLabel);
209 }
210 }
211
212
214 Arrays.sort(table, 0, ti);
215
216
218 int[] keys = new int[ti];
219 Label[] labels = new Label[ti];
220 for (int i = 0; i < ti; i++) {
221 keys[i] = table[i].i;
222 labels[i] = table[i].l;
223 }
224
225 if (hasCases) {
226 getExpr().cgValue(cb);
227 cb.emitSwitch(keys, labels, defaultLab);
228 } else {
229 getExpr().cgEffect(cb);
230 }
231
232 cb.enterNonWindingContext(this, endLab, null);
234 for (int i = 0; i < len; i++ ) {
235 Label caseCodeLabel = clauseStarts[i];
236 Stmts caseCode = getClauses().get(i).getStmts();
237 cb.emitLabel(caseCodeLabel);
238 caseCode.cgStmts(cb);
239 }
240 cb.leaveContext();
241 cb.emitLabel(endLab);
242 }
243
244
247
249 public void walkFrameLoc(FrameLocPass walker) {
250 int start = walker.getfs();
251 super.walkFrameLoc(walker);
252 walker.setfs(start);
253 }
254
255
258
283
284 protected Expr expr;
286 public Expr getExpr() { return expr; }
287 public void setExpr(Expr _expr) {
288 if (_expr != null) _expr.setParent(this);
289 expr = _expr;
290 }
291
292 protected SwitchClauses clauses;
293 public SwitchClauses getClauses() { return clauses; }
294 public void setClauses(SwitchClauses _clauses) {
295 if (_clauses != null) _clauses.setParent(this);
296 clauses = _clauses;
297 }
298
299 public SwitchStmt(SourceLocation location, Expr _expr, SwitchClauses _clauses) {
300 super(location);
301 setExpr(_expr);
302 setClauses(_clauses);
303 }
304 protected SwitchStmt(SourceLocation source) {
305 super(source);
306 }
307
308 public ASTObject copyWalk(CopyWalker walker) {
309 SwitchStmt ret = new SwitchStmt(getSourceLocation());
310 ret.preCopy(walker, this);
311 if (expr != null) ret.setExpr( (Expr)walker.process(expr) );
312 if (clauses != null) ret.setClauses( (SwitchClauses)walker.process(clauses) );
313 return ret;
314 }
315
316 public ASTObject getChildAt(int childIndex) {
317 switch(childIndex) {
318 case 0: return expr;
319 case 1: return clauses;
320 default: return super.getChildAt(childIndex);
321 }
322 }
323 public String getChildNameAt(int childIndex) {
324 switch(childIndex) {
325 case 0: return "expr";
326 case 1: return "clauses";
327 default: return super.getChildNameAt(childIndex);
328 }
329 }
330 public void setChildAt(int childIndex, ASTObject child) {
331 switch(childIndex) {
332 case 0: setExpr((Expr)child); return;
333 case 1: setClauses((SwitchClauses)child); return;
334 default: super.setChildAt(childIndex, child); return;
335 }
336 }
337 public int getChildCount() {
338 return 2;
339 }
340
341 public String getDefaultDisplayName() {
342 return "SwitchStmt()";
343 }
344
345 }
347
348
349 |
Popular Tags |
Java API By Example, From Geeks To Geeks.