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1
19
20 package edu.umd.cs.findbugs.ba;
21
22 import org.apache.bcel.generic.IFNONNULL;
23 import org.apache.bcel.generic.IFNULL;
24 import org.apache.bcel.generic.Instruction;
25 import org.apache.bcel.generic.InstructionHandle;
26 import org.apache.bcel.generic.MethodGen;
27
28 import edu.umd.cs.findbugs.SystemProperties;
29 import edu.umd.cs.findbugs.annotations.DefaultAnnotationForParameters;
30 import edu.umd.cs.findbugs.annotations.NonNull;
31
32 @DefaultAnnotationForParameters(NonNull.class)
33 public class ResourceValueAnalysis <Resource> extends FrameDataflowAnalysis<ResourceValue, ResourceValueFrame>
34 implements EdgeTypes {
35
36 private static final boolean DEBUG = SystemProperties.getBoolean("dataflow.debug");
37
38 private MethodGen methodGen;
39 private CFG cfg;
40 private ResourceTracker<Resource> resourceTracker;
41 private Resource resource;
42 private ResourceValueFrameModelingVisitor visitor;
43 private boolean ignoreImplicitExceptions;
44
45 public ResourceValueAnalysis(MethodGen methodGen, CFG cfg, DepthFirstSearch dfs,
46 ResourceTracker<Resource> resourceTracker, Resource resource) {
47
48 super(dfs);
49 this.methodGen = methodGen;
50 this.cfg = cfg;
51 this.resourceTracker = resourceTracker;
52 this.resource = resource;
53 this.visitor = resourceTracker.createVisitor(resource, methodGen.getConstantPool());
54
55 this.ignoreImplicitExceptions = resourceTracker.ignoreImplicitExceptions(resource);
56 }
57
58 public ResourceValueFrame createFact() {
59 ResourceValueFrame fact = new ResourceValueFrame(methodGen.getMaxLocals());
60 fact.setTop();
61 return fact;
62 }
63
64 public void initEntryFact(ResourceValueFrame result) {
65 result.setValid();
66 result.clearStack();
67 final int numSlots = result.getNumSlots();
68 for (int i = 0; i < numSlots; ++i) {
69 boolean slotContainsInstance = resourceTracker.isParamInstance(resource, i);
70 result.setValue(i, slotContainsInstance ? ResourceValue.instance() : ResourceValue.notInstance());
71 }
72 }
73
74 public void meetInto(ResourceValueFrame fact, Edge edge, ResourceValueFrame result) throws DataflowAnalysisException {
75 BasicBlock source = edge.getSource();
76 BasicBlock dest = edge.getTarget();
77
78 ResourceValueFrame tmpFact = null;
79
80 if (edge.isExceptionEdge()) {
81 if (AnalysisContext.currentAnalysisContext().getBoolProperty(AnalysisFeatures.ACCURATE_EXCEPTIONS) &&
86 ignoreImplicitExceptions &&
87 !edge.isFlagSet(EXPLICIT_EXCEPTIONS_FLAG))
88 return;
89
90 if (resourceTracker.ignoreExceptionEdge(edge, resource, methodGen.getConstantPool()))
92 return;
93
94 if (fact.getStatus() == ResourceValueFrame.OPEN) {
95 tmpFact = modifyFrame(fact, null);
97 tmpFact.setStatus(ResourceValueFrame.OPEN_ON_EXCEPTION_PATH);
98 }
99
100 if (fact.isValid()) {
101 InstructionHandle exceptionThrower = source.getExceptionThrower();
105 BasicBlock fallThroughSuccessor = cfg.getSuccessorWithEdgeType(source, FALL_THROUGH_EDGE);
106 if (DEBUG && fallThroughSuccessor == null) System.out.println("Null fall through successor!");
107 if (fallThroughSuccessor != null &&
108 resourceTracker.isResourceClose(fallThroughSuccessor, exceptionThrower, methodGen.getConstantPool(), resource, fact)) {
109 tmpFact = modifyFrame(fact, tmpFact);
110 tmpFact.setStatus(ResourceValueFrame.CLOSED);
111 if (DEBUG) System.out.print("(failed attempt to close)");
112 }
113 }
114
115 if (dest.isExceptionHandler()) {
116 if (fact.isValid()) {
118 tmpFact = modifyFrame(fact, tmpFact);
119 tmpFact.clearStack();
120 tmpFact.pushValue(ResourceValue.notInstance());
121 }
122 }
123 }
124
125 int edgeType = edge.getType();
127 if (edgeType == IFCMP_EDGE || edgeType == FALL_THROUGH_EDGE) {
128 InstructionHandle lastInSourceHandle = source.getLastInstruction();
129 if (lastInSourceHandle != null) {
130 Instruction lastInSource = lastInSourceHandle.getInstruction();
131 if (lastInSource instanceof IFNULL || lastInSource instanceof IFNONNULL) {
132 ResourceValueFrame startFrame = getStartFact(source);
134 if (startFrame.isValid()) {
135 ResourceValueFrame frameAtIf = getFactAtLocation(new Location(lastInSourceHandle, source));
138 ResourceValue topValue = frameAtIf.getValue(frameAtIf.getNumSlots() - 1);
139
140 if (topValue.isInstance()) {
141 if ((lastInSource instanceof IFNULL && edgeType == IFCMP_EDGE) ||
142 (lastInSource instanceof IFNONNULL && edgeType == FALL_THROUGH_EDGE)) {
143 tmpFact = modifyFrame(fact, tmpFact);
145 tmpFact.setStatus(ResourceValueFrame.NONEXISTENT);
146 }
147 }
148 }
149 }
150 }
151 }
152
153 if (tmpFact != null)
154 fact = tmpFact;
155
156 mergeInto(fact, result);
157 }
158
159 @Override 
160 protected void mergeInto(ResourceValueFrame frame, ResourceValueFrame result)
161 throws DataflowAnalysisException {
162 super.mergeInto(frame, result);
164
165 result.setStatus(Math.min(result.getStatus(), frame.getStatus()));
167 }
168
169 @Override
171 protected void mergeValues(ResourceValueFrame otherFrame, ResourceValueFrame resultFrame, int slot) throws DataflowAnalysisException {
172 ResourceValue value = ResourceValue.merge(resultFrame.getValue(slot), otherFrame.getValue(slot));
173 resultFrame.setValue(slot, value);
174 }
175
176 @Override
177 public void transferInstruction(InstructionHandle handle, BasicBlock basicBlock, ResourceValueFrame fact)
178 throws DataflowAnalysisException {
179
180 visitor.setFrameAndLocation(fact, new Location(handle, basicBlock));
181 visitor.transferInstruction(handle, basicBlock);
182
183 }
184
185 }
186
187 |
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