FindBugs™ 1.3.9

edu.umd.cs.findbugs.detect
Class FindUselessControlFlow

java.lang.Object
  extended by edu.umd.cs.findbugs.visitclass.BetterVisitor
      extended by edu.umd.cs.findbugs.visitclass.PreorderVisitor
          extended by edu.umd.cs.findbugs.visitclass.AnnotationVisitor
              extended by edu.umd.cs.findbugs.visitclass.DismantleBytecode
                  extended by edu.umd.cs.findbugs.BytecodeScanningDetector
                      extended by edu.umd.cs.findbugs.detect.FindUselessControlFlow
All Implemented Interfaces:
Detector, Priorities, StatelessDetector, Constants2, java.lang.Cloneable, org.apache.bcel.classfile.Visitor, org.apache.bcel.Constants

public class FindUselessControlFlow
extends BytecodeScanningDetector
implements StatelessDetector

A Detector to look for useless control flow. For example,

     if (argv.length == 1);
         System.out.println("Hello, " + argv[0]);
 
In this kind of bug, we'll see an ifcmp instruction where the IF target is the same as the fall-through target.

The idea for this detector came from Richard P. King, and the idea of looking for if instructions with identical branch and fall-through targets is from Mike Fagan.

Author:
David Hovemeyer

Field Summary
 
Fields inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode
codeBytes, lineNumberTable, M_BR, M_CP, M_INT, M_PAD, M_R, M_UINT
 
Fields inherited from interface edu.umd.cs.findbugs.Priorities
EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY
 
Fields inherited from interface org.apache.bcel.Constants
AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACCESS_NAMES, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ANEWARRAY_QUICK, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, ATTR_ANNOTATION_DEFAULT, ATTR_CODE, ATTR_CONSTANT_VALUE, ATTR_DEPRECATED, ATTR_EXCEPTIONS, ATTR_INNER_CLASSES, ATTR_LINE_NUMBER_TABLE, ATTR_LOCAL_VARIABLE_TABLE, ATTR_LOCAL_VARIABLE_TYPE_TABLE, ATTR_PMG, ATTR_RUNTIMEINVISIBLE_ANNOTATIONS, ATTR_RUNTIMEINVISIBLE_PARAMETER_ANNOTATIONS, ATTR_RUNTIMEVISIBLE_ANNOTATIONS, ATTR_RUNTIMEVISIBLE_PARAMETER_ANNOTATIONS, ATTR_SIGNATURE, ATTR_SOURCE_FILE, ATTR_STACK_MAP, ATTR_SYNTHETIC, ATTR_UNKNOWN, ATTRIBUTE_NAMES, BALOAD, BASTORE, BIPUSH, BREAKPOINT, CALOAD, CASTORE, CHECKCAST, CHECKCAST_QUICK, CLASS_TYPE_NAMES, CONSTANT_Class, CONSTANT_Double, CONSTANT_Fieldref, CONSTANT_Float, CONSTANT_Integer, CONSTANT_InterfaceMethodref, CONSTANT_Long, CONSTANT_Methodref, CONSTANT_NameAndType, CONSTANT_NAMES, CONSTANT_String, CONSTANT_Utf8, CONSTRUCTOR_NAME, CONSUME_STACK, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, GETFIELD, GETFIELD_QUICK, GETFIELD_QUICK_W, GETFIELD2_QUICK, GETSTATIC, GETSTATIC_QUICK, GETSTATIC2_QUICK, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILLEGAL_OPCODE, ILLEGAL_TYPE, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMPDEP1, IMPDEP2, IMUL, INEG, INSTANCEOF, INSTANCEOF_QUICK, INT2BYTE, INT2CHAR, INT2SHORT, INTERFACES_IMPLEMENTED_BY_ARRAYS, INVOKEINTERFACE, INVOKEINTERFACE_QUICK, INVOKENONVIRTUAL, INVOKENONVIRTUAL_QUICK, INVOKESPECIAL, INVOKESTATIC, INVOKESTATIC_QUICK, INVOKESUPER_QUICK, INVOKEVIRTUAL, INVOKEVIRTUAL_QUICK, INVOKEVIRTUAL_QUICK_W, INVOKEVIRTUALOBJECT_QUICK, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, ITEM_Bogus, ITEM_Double, ITEM_Float, ITEM_InitObject, ITEM_Integer, ITEM_Long, ITEM_NAMES, ITEM_NewObject, ITEM_Null, ITEM_Object, IUSHR, IXOR, JSR, JSR_W, KNOWN_ATTRIBUTES, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_QUICK, LDC_W, LDC_W_QUICK, LDC2_W, LDC2_W_QUICK, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MAJOR, MAJOR_1_1, MAJOR_1_2, MAJOR_1_3, MAJOR_1_4, MAJOR_1_5, MAX_ACC_FLAG, MAX_BYTE, MAX_CODE_SIZE, MAX_CP_ENTRIES, MAX_SHORT, MINOR, MINOR_1_1, MINOR_1_2, MINOR_1_3, MINOR_1_4, MINOR_1_5, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, MULTIANEWARRAY_QUICK, NEW, NEW_QUICK, NEWARRAY, NO_OF_OPERANDS, NOP, OPCODE_NAMES, POP, POP2, PRODUCE_STACK, PUSH, PUTFIELD, PUTFIELD_QUICK, PUTFIELD_QUICK_W, PUTFIELD2_QUICK, PUTSTATIC, PUTSTATIC_QUICK, PUTSTATIC2_QUICK, RESERVED, RET, RETURN, SALOAD, SASTORE, SHORT_TYPE_NAMES, SIPUSH, STATIC_INITIALIZER_NAME, SWAP, SWITCH, T_ADDRESS, T_ARRAY, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_OBJECT, T_REFERENCE, T_SHORT, T_UNKNOWN, T_VOID, TABLESWITCH, TYPE_NAMES, TYPE_OF_OPERANDS, UNDEFINED, UNPREDICTABLE, WIDE
 
Constructor Summary
FindUselessControlFlow(BugReporter bugReporter)
           
 
Method Summary
static int getNextSourceLine(org.apache.bcel.classfile.LineNumberTable lineNumbers, int sourceLine)
           
 void sawOpcode(int seen)
           
 void visit(org.apache.bcel.classfile.Code obj)
           
 
Methods inherited from class edu.umd.cs.findbugs.BytecodeScanningDetector
getClassContext, report, visitClassContext
 
Methods inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode
afterOpcode, areOppositeBranches, atCatchBlock, beforeOpcode, getBranchFallThrough, getBranchOffset, getBranchTarget, getClassConstantOperand, getClassDescriptorOperand, getCodeByte, getConstantRefOperand, getDefaultSwitchOffset, getDottedClassConstantOperand, getDottedSigConstantOperand, getFieldDescriptorOperand, getIntConstant, getMaxPC, getMethodDescriptorOperand, getNameConstantOperand, getNextOpcode, getNextPC, getOpcode, getPC, getPrevOpcode, getRefConstantOperand, getRefFieldIsStatic, getRegisterOperand, getSigConstantOperand, getStringConstantOperand, getSwitchLabels, getSwitchOffsets, getXClassOperand, getXFieldOperand, getXMethodOperand, isBranch, isRegisterLoad, isRegisterStore, isRegisterStore, isReturn, isSwitch, isWideOpcode, printOpCode, sawBranchTo, sawClass, sawDouble, sawField, sawFloat, sawIMethod, sawInt, sawLong, sawMethod, sawOffset, sawRegister, sawString
 
Methods inherited from class edu.umd.cs.findbugs.visitclass.AnnotationVisitor
visit, visitAnnotation, visitParameterAnnotation, visitSyntheticParameterAnnotation
 
Methods inherited from class edu.umd.cs.findbugs.visitclass.PreorderVisitor
amVisitingMainMethod, asUnsignedByte, doVisitMethod, getClassDescriptor, getClassName, getCode, getConstantPool, getDottedClassName, getDottedFieldSig, getDottedMethodSig, getDottedSuperclassName, getField, getFieldDescriptor, getFieldIsStatic, getFieldName, getFieldSig, getFullyQualifiedFieldName, getFullyQualifiedMethodName, getMethod, getMethodDescriptor, getMethodName, getMethodSig, getNumberArguments, getNumberMethodArguments, getPackageName, getSizeOfSurroundingTryBlock, getSizeOfSurroundingTryBlock, getSourceFile, getStringFromIndex, getSuperclassName, getSurroundingCaughtExceptions, getThisClass, getXClass, getXField, getXMethod, setupVisitorForClass, shouldVisit, visitAfter, visitCode, visitConstantPool, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable
 
Methods inherited from class edu.umd.cs.findbugs.visitclass.BetterVisitor
clone, report, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitCodeException, visitConstantClass, visitConstantDouble, visitConstantFieldref, visitConstantFloat, visitConstantInteger, visitConstantInterfaceMethodref, visitConstantLong, visitConstantMethodref, visitConstantNameAndType, visitConstantString, visitConstantUtf8, visitConstantValue, visitDeprecated, visitExceptionTable, visitField, visitInnerClass, visitLineNumber, visitLocalVariable, visitLocalVariableTypeTable, visitMethod, visitSignature, visitSourceFile, visitStackMap, visitStackMapEntry, visitSynthetic, visitUnknown
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface edu.umd.cs.findbugs.StatelessDetector
clone
 

Constructor Detail

FindUselessControlFlow

public FindUselessControlFlow(BugReporter bugReporter)
Method Detail

visit

public void visit(org.apache.bcel.classfile.Code obj)
Overrides:
visit in class DismantleBytecode

sawOpcode

public void sawOpcode(int seen)
Overrides:
sawOpcode in class DismantleBytecode

getNextSourceLine

public static int getNextSourceLine(org.apache.bcel.classfile.LineNumberTable lineNumbers,
                                    int sourceLine)

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