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1
19
20 package edu.umd.cs.findbugs.detect;
21
22
23 import org.apache.bcel.Repository;
24 import org.apache.bcel.classfile.Code;
25 import org.apache.bcel.classfile.JavaClass;
26
27 import edu.umd.cs.findbugs.BugInstance;
28 import edu.umd.cs.findbugs.BugReporter;
29 import edu.umd.cs.findbugs.BytecodeScanningDetector;
30 import edu.umd.cs.findbugs.OpcodeStack;
31 import edu.umd.cs.findbugs.OpcodeStack.Item;
32
33 public class FindPuzzlers extends BytecodeScanningDetector {
34
35
36 BugReporter bugReporter;
37 public FindPuzzlers(BugReporter bugReporter) {
38 this.bugReporter = bugReporter;
39 }
40
41
42
43 @Override 
44 public void visit(Code obj) {
45 prevOpcodeIncrementedRegister = -1;
46 best_priority_for_ICAST_INTEGER_MULTIPLY_CAST_TO_LONG = LOW_PRIORITY+1;
47 prevOpCode = NOP;
48 stack.resetForMethodEntry(this);
49 badlyComputingOddState = 0;
50 resetIMulCastLong();
51 imul_distance = 10000;
52 super.visit(obj);
53 }
54
55 int imul_constant;
56 int imul_distance;
57 boolean imul_operand_is_parameter;
58 int prevOpcodeIncrementedRegister;
59 int valueOfConstantArgumentToShift;
60 int best_priority_for_ICAST_INTEGER_MULTIPLY_CAST_TO_LONG ;
61 boolean constantArgumentToShift;
62
63 int badlyComputingOddState;
64 int prevOpCode;
65 OpcodeStack stack = new OpcodeStack();
66
67 private void resetIMulCastLong() {
68 imul_constant = 1;
69 imul_operand_is_parameter = false;
70 }
71 private int adjustPriority(int factor, int priority) {
72 if (factor <= 4) return LOW_PRIORITY+2;
73 if (factor <= 10000) return priority+1;
74 if (factor <= 60*60*1000) return priority;
75 return priority-1;
76 }
77 private int adjustMultiplier(Object constant, int mul) {
78 if (!(constant instanceof Integer )) return mul;
79 return Math.abs(((Integer ) constant).intValue()) * mul;
80
81 }
82 @Override
83 public void sawOpcode(int seen) {
84 stack.mergeJumps(this);
85
86 if (seen == IMUL) {
87 if (imul_distance != 1) resetIMulCastLong();
88 imul_distance = 0;
89 if (stack.getStackDepth() > 1) {
90 OpcodeStack.Item item0 = stack.getStackItem(0);
91 OpcodeStack.Item item1 = stack.getStackItem(1);
92 imul_constant = adjustMultiplier(item0.getConstant(), imul_constant);
93 imul_constant = adjustMultiplier(item1.getConstant(), imul_constant);
94
95 if (item0.isInitialParameter() || item1.isInitialParameter())
96 imul_operand_is_parameter = true;
97 }} else {
98 imul_distance++;
99 }
100
101 if (prevOpCode == IMUL && seen == I2L) {
102 int priority = adjustPriority(imul_constant, NORMAL_PRIORITY);
103 if (priority >= LOW_PRIORITY && imul_operand_is_parameter) priority = NORMAL_PRIORITY;
104 if (priority <= best_priority_for_ICAST_INTEGER_MULTIPLY_CAST_TO_LONG) {
105 best_priority_for_ICAST_INTEGER_MULTIPLY_CAST_TO_LONG = priority;
106 bugReporter.reportBug(new BugInstance(this,
107 "ICAST_INTEGER_MULTIPLY_CAST_TO_LONG",
108 priority)
109 .addClassAndMethod(this)
110 .addSourceLine(this));
111 }
112 }
113
114 if (getMethodName().equals("<clinit>") && (seen == PUTSTATIC || seen == GETSTATIC || seen == INVOKESTATIC)) {
115 String clazz = getClassConstantOperand();
116 if (!clazz.equals(getClassName())) {
117 try {
118 JavaClass targetClass = Repository.lookupClass(clazz);
119 if (Repository.instanceOf(targetClass, getThisClass())) {
120 int priority = NORMAL_PRIORITY;
121 if (seen == GETSTATIC) priority--;
122 if (!targetClass.isPublic()) priority++;
123 bugReporter.reportBug(new BugInstance(this,
124 "IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION",
125 priority)
126 .addClassAndMethod(this).addClass(getDottedClassConstantOperand())
127 .addSourceLine(this)
128 );
129 }
130 } catch (ClassNotFoundException e) {
131 }
133
134 }
135 }
136 if (false && (seen == INVOKEVIRTUAL)
137 && getNameConstantOperand().equals("equals")
138 && getSigConstantOperand().equals("(Ljava/lang/Object;)Z")
139 && stack.getStackDepth() > 1) {
140 OpcodeStack.Item item0 = stack.getStackItem(0);
141 OpcodeStack.Item item1 = stack.getStackItem(1);
142
143 if (item0.isArray() || item1.isArray()) {
144 bugReporter.reportBug(new BugInstance("EC_BAD_ARRAY_COMPARE", NORMAL_PRIORITY)
145 .addClassAndMethod(this)
146 .addSourceLine(this));
147 }
148 }
149
150
151 if (seen >= IALOAD && seen <= SALOAD || seen >= IASTORE && seen <= SASTORE ) {
152 Item index = stack.getStackItem(0);
153 if (index.getSpecialKind() == Item.AVERAGE_COMPUTED_USING_DIVISION)
154 bugReporter.reportBug(new BugInstance(this, "IM_AVERAGE_COMPUTATION_COULD_OVERFLOW", NORMAL_PRIORITY)
155 .addClassAndMethod(this)
156 .addSourceLine(this));
157 }
158
159 if ((seen == IFEQ || seen == IFNE) && getPrevOpcode(1) == IMUL
160 && ( getPrevOpcode(2) == SIPUSH
161 || getPrevOpcode(2) == BIPUSH
162 )
163 && getPrevOpcode(3) == IREM
164 )
165 bugReporter.reportBug(new BugInstance(this, "IM_MULTIPLYING_RESULT_OF_IREM", LOW_PRIORITY)
166 .addClassAndMethod(this)
167 .addSourceLine(this));
168 if (seen == I2S && getPrevOpcode(1) == IUSHR
169 && (!constantArgumentToShift || valueOfConstantArgumentToShift % 16 != 0)
170 ||
171 seen == I2B && getPrevOpcode(1) == IUSHR
172 && (!constantArgumentToShift || valueOfConstantArgumentToShift % 8 != 0)
173 )
174 bugReporter.reportBug(new BugInstance(this, "ICAST_QUESTIONABLE_UNSIGNED_RIGHT_SHIFT", LOW_PRIORITY)
175 .addClassAndMethod(this)
176 .addSourceLine(this));
177
178 constantArgumentToShift = false;
179 if ( (seen == IUSHR
180 || seen == ISHR
181 || seen == ISHL )) {
182 if (stack.getStackDepth() <= 1) {
183 constantArgumentToShift = true;
185 valueOfConstantArgumentToShift = 8;
186 }
187 else {
188 Object rightHandSide
189 = stack.getStackItem(0).getConstant();
190 Object leftHandSide
191 = stack.getStackItem(1).getConstant();
192 if (rightHandSide instanceof Integer ) {
193 constantArgumentToShift = true;
194 valueOfConstantArgumentToShift = ((Integer ) rightHandSide);
195 if (valueOfConstantArgumentToShift < 0 || valueOfConstantArgumentToShift >= 32)
196 bugReporter.reportBug(new BugInstance(this, "ICAST_BAD_SHIFT_AMOUNT",
197 valueOfConstantArgumentToShift < 0 ? LOW_PRIORITY : HIGH_PRIORITY)
198 .addClassAndMethod(this)
199 .addInt(valueOfConstantArgumentToShift)
200 .addSourceLine(this)
201 );
202 }
203 if (leftHandSide != null
204 && leftHandSide instanceof Integer
205 && ((Integer ) leftHandSide)
206 > 0) {
207 constantArgumentToShift = true;
209 valueOfConstantArgumentToShift = 8;
210 }
211 }
212 }
213
214
215
216 if (seen == INVOKEVIRTUAL && stack.getStackDepth() > 0
217 && getClassConstantOperand().equals("java/util/Date")
218 && getNameConstantOperand().equals("setMonth")
219 && getSigConstantOperand().equals("(I)V")) {
220 OpcodeStack.Item item = stack.getStackItem(0);
221 Object o = item.getConstant();
222 if (o != null && o instanceof Integer ) {
223 int v = (Integer ) o;
224 if (v < 0 || v > 11)
225 bugReporter.reportBug(new BugInstance(this, "DMI_BAD_MONTH", NORMAL_PRIORITY)
226 .addClassAndMethod(this)
227 .addInt(v)
228 .addCalledMethod(this)
229 .addSourceLine(this)
230 );
231 }
232 }
233
234 if (seen == INVOKEVIRTUAL && stack.getStackDepth() > 1
235 && getClassConstantOperand().equals("java/util/Calendar")
236 && getNameConstantOperand().equals("set")
237 && getSigConstantOperand().equals("(III)V")
238 ||
239 seen == INVOKESPECIAL && stack.getStackDepth() > 1
240 && getClassConstantOperand().equals("java/util/GregorianCalendar")
241 && getNameConstantOperand().equals("<init>")
242 && getSigConstantOperand().equals("(III)V")
243 ) {
244 OpcodeStack.Item item = stack.getStackItem(1);
245 Object o = item.getConstant();
246 if (o != null && o instanceof Integer ) {
247 int v = (Integer ) o;
248 if (v < 0 || v > 11)
249 bugReporter.reportBug(new BugInstance(this, "DMI_BAD_MONTH", NORMAL_PRIORITY)
250 .addClassAndMethod(this)
251 .addInt(v)
252 .addCalledMethod(this)
253 .addSourceLine(this)
254 );
255 }
256 }
257
258
259
260 if (isRegisterStore() && (seen == ISTORE
261 || seen == ISTORE_0
262 || seen == ISTORE_1
263 || seen == ISTORE_2
264 || seen == ISTORE_3)
265 && getRegisterOperand() == prevOpcodeIncrementedRegister) {
266 bugReporter.reportBug(new BugInstance(this, "DLS_OVERWRITTEN_INCREMENT", HIGH_PRIORITY)
267 .addClassAndMethod(this)
268 .addSourceLine(this));
269
270 }
271 if (seen == IINC) {
272 prevOpcodeIncrementedRegister = getRegisterOperand();
273 }
274 else
275 prevOpcodeIncrementedRegister = -1;
276
277
278
281 switch (badlyComputingOddState) {
282 case 0:
283 if (seen == ICONST_2) badlyComputingOddState++;
284 break;
285 case 1:
286 if (seen == IREM) badlyComputingOddState++;
287 else badlyComputingOddState = 0;
288 break;
289 case 2:
290 if (seen == ICONST_1) badlyComputingOddState++;
291 else badlyComputingOddState = 0;
292 break;
293 case 3:
294 if (seen == IF_ICMPEQ || seen == IF_ICMPNE)
295 bugReporter.reportBug(new BugInstance(this, "IM_BAD_CHECK_FOR_ODD", NORMAL_PRIORITY)
296 .addClassAndMethod(this)
297 .addSourceLine(this));
298 badlyComputingOddState = 0;
299 break;
300 }
301
302 if (seen == INVOKEVIRTUAL && stack.getStackDepth() > 0
304 && (getNameConstantOperand().equals("toString")
305 && getSigConstantOperand().equals("()Ljava/lang/String;")
306 || getNameConstantOperand().equals("append")
307 && getSigConstantOperand().equals("(Ljava/lang/Object;)Ljava/lang/StringBuilder;") && getClassConstantOperand().equals("java/lang/StringBuilder")
308 || getNameConstantOperand().equals("append")
309 && getSigConstantOperand().equals("(Ljava/lang/Object;)Ljava/lang/StringBuffer;") && getClassConstantOperand().equals("java/lang/StringBuffer")
310 )
311 ) {
312 String classConstants = getClassConstantOperand();
313 OpcodeStack.Item item = stack.getStackItem(0);
314 String signature = item.getSignature();
315 if (signature != null && signature.startsWith("["))
316 bugReporter.reportBug(new BugInstance(this, "DMI_INVOKING_TOSTRING_ON_ARRAY", NORMAL_PRIORITY)
317 .addClassAndMethod(this)
318 .addSourceLine(this));
319 }
320
321
322
323 stack.sawOpcode(this,seen);
324 prevOpCode = seen;
325 }
326
327 }
328 |
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