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1
24
25 package org.aspectj.compiler.base.ast;
26
27 import org.aspectj.compiler.base.*;
28 import org.aspectj.compiler.base.JavaCompiler;
29 import org.aspectj.compiler.base.CodeWriter;
30
31 import org.aspectj.compiler.base.bcg.CodeBuilder;
32 import org.aspectj.compiler.base.bcg.Label;
33
34
40
41 public class IfStmt extends TestStmt {
42
43 public void unparse(CodeWriter writer) {
44 writer.writeKeyword("if");
45 writer.optionalSpace();
46 writer.parenExpr(test);
47 writer.optionalSpace();
48 writer.write(then);
49 if (! (_else instanceof EmptyStmt && _else.isSynthetic())) {
50 writer.writeKeyword("else");
51 writer.optionalSpace();
52 writer.write(_else);
53 }
54 }
55
56 public void checkSpec() {
57 then.requireStmt();
58 if (_else != null) _else.requireStmt();
59 super.checkSpec();
60 }
61
62
65 public void walkFlow(FlowCheckerPass w) {
66 w.processBoolean(getTest());
68 FlowCheckerPass.Vars p0 = w.getVars();
69
70 w.setVars(p0.getTrue());
71 w.process(getThen());
72 FlowCheckerPass.Vars v0 = w.getVars();
73 boolean trueLive = w.isLive();
74
75 w.setLive(true);
76 w.setVars(p0.getFalse());
77 w.process(getElse());
78 FlowCheckerPass.Vars v1 = w.getVars();
79 boolean falseLive = w.isLive();
80
81 w.setLive(falseLive || trueLive);
82 w.setVars(v0.join(v1));
83 }
84
85
88 public void walkCleanup(ByteCodeCleanupPass w) {
89 if (getTest().isConstantTrue()) {
90 w.process(getThen());
91 } else if (getTest().isConstantFalse()) {
92 w.process(getElse());
93 } else {
94 w.setLive(true);
95 setThen((Stmt) w.process(getThen()));
96 boolean thenLive = w.isLive();
97 w.setLive(true);
98 setElse((Stmt) w.process(getElse()));
99 w.setLive(thenLive || w.isLive());
100 }
101 }
102
103 public ASTObject postCleanup(ByteCodeCleanupPass w) {
104 if (getTest().isConstantTrue()) {
105 return getThen();
106 } else if (getTest().isConstantFalse()) {
107 return getElse();
108 } else if (getThen() instanceof EmptyStmt
109 && getElse() instanceof EmptyStmt) {
110 return getAST().makeStmt(getTest()).setSource(this);
111 } else {
112 return this;
113 }
114 }
115
116
119 protected void cgStmt(CodeBuilder cb) {
120 Label trueLab = cb.genLabel();
121 Label falseLab = cb.genLabel();
122 Label endLab = cb.genLabel();
123 getTest().cgTest(cb, trueLab, falseLab);
124 cb.emitLabel(trueLab);
125 getThen().cgTop(cb);
126 if (getThen().completesNormally()) {
127 cb.emitJump(endLab);
128 }
129 cb.emitLabel(falseLab);
130 getElse().cgTop(cb);
131 cb.emitLabel(endLab);
132 }
133
134 protected Expr test;
136 public Expr getTest() { return test; }
137 public void setTest(Expr _test) {
138 if (_test != null) _test.setParent(this);
139 test = _test;
140 }
141
142 protected Stmt then;
143 public Stmt getThen() { return then; }
144 public void setThen(Stmt _then) {
145 if (_then != null) _then.setParent(this);
146 then = _then;
147 }
148
149 protected Stmt _else;
150 public Stmt getElse() { return _else; }
151 public void setElse(Stmt __else) {
152 if (__else != null) __else.setParent(this);
153 _else = __else;
154 }
155
156 public IfStmt(SourceLocation location, Expr _test, Stmt _then, Stmt __else) {
157 super(location);
158 setTest(_test);
159 setThen(_then);
160 setElse(__else);
161 }
162 protected IfStmt(SourceLocation source) {
163 super(source);
164 }
165
166 public ASTObject copyWalk(CopyWalker walker) {
167 IfStmt ret = new IfStmt(getSourceLocation());
168 ret.preCopy(walker, this);
169 if (test != null) ret.setTest( (Expr)walker.process(test) );
170 if (then != null) ret.setThen( (Stmt)walker.process(then) );
171 if (_else != null) ret.setElse( (Stmt)walker.process(_else) );
172 return ret;
173 }
174
175 public ASTObject getChildAt(int childIndex) {
176 switch(childIndex) {
177 case 0: return test;
178 case 1: return then;
179 case 2: return _else;
180 default: return super.getChildAt(childIndex);
181 }
182 }
183 public String  getChildNameAt(int childIndex) {
184 switch(childIndex) {
185 case 0: return "test";
186 case 1: return "then";
187 case 2: return "else";
188 default: return super.getChildNameAt(childIndex);
189 }
190 }
191 public void setChildAt(int childIndex, ASTObject child) {
192 switch(childIndex) {
193 case 0: setTest((Expr)child); return;
194 case 1: setThen((Stmt)child); return;
195 case 2: setElse((Stmt)child); return;
196 default: super.setChildAt(childIndex, child); return;
197 }
198 }
199 public int getChildCount() {
200 return 3;
201 }
202
203 public String getDefaultDisplayName() {
204 return "IfStmt()";
205 }
206
207 }
209
210
211 |
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