Package com.mebigfatguy.fbcontrib.detect

Class UnnecessaryStoreBeforeReturn

java.lang.Object
edu.umd.cs.findbugs.visitclass.BetterVisitor
edu.umd.cs.findbugs.visitclass.PreorderVisitor
edu.umd.cs.findbugs.visitclass.AnnotationVisitor
edu.umd.cs.findbugs.visitclass.DismantleBytecode
edu.umd.cs.findbugs.BytecodeScanningDetector
com.mebigfatguy.fbcontrib.detect.UnnecessaryStoreBeforeReturn
All Implemented Interfaces:
edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, org.apache.bcel.classfile.Visitor
@CustomUserValue public class UnnecessaryStoreBeforeReturn extends edu.umd.cs.findbugs.BytecodeScanningDetector
Looks for methods that store the return result in a local variable, and then immediately returns that local variable.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    (package private) static enum 
    UnnecessaryStoreBeforeReturn.State
     

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final BitSet
    binaryOps
     
    private static final BitSet
    branchInstructions
     
    private BitSet
    branchTargets
     
    private final edu.umd.cs.findbugs.BugReporter
    bugReporter
     
    private BitSet
    catchTargets
     
    private edu.umd.cs.findbugs.OpcodeStack
    stack
     
    private UnnecessaryStoreBeforeReturn.State
    state
     
    private int
    storeReg
     

    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

  • Constructor Summary

    Constructors
    Constructor
    Description
    UnnecessaryStoreBeforeReturn(edu.umd.cs.findbugs.BugReporter bugReporter)
    constructs a USBR detector given the reporter to report bugs on

  • Method Summary

    Modifier and Type
    Method
    Description
    private boolean
    lookForLoad(int seen)
    looks for a load of the register that was just stored
    private boolean
    lookForStore(int seen)
    checks if the current opcode is a store, if so saves the register
    private int
    processBinOp(int seen)
    looks for instructions that are binary operators, and if it is saves the left hand side register (if it exists) in the userValue.
    void
    sawOpcode(int seen)
    implements the visitor to look for store of registers immediately before returns of that register
    void
    visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)
    implements the visitor to create and clear the branchTargets
    void
    visitCode(org.apache.bcel.classfile.Code obj)
    implements the visitor to make sure method returns a value, and then clears the targets

    Methods inherited from class edu.umd.cs.findbugs.BytecodeScanningDetector

    getClassContext, report, shouldVisitCode

    Methods inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode

    afterOpcode, areOppositeBranches, atCatchBlock, beforeOpcode, getBranchFallThrough, getBranchOffset, getBranchTarget, getClassConstantOperand, getClassDescriptorOperand, getCodeByte, getConstantRefOperand, getDefaultSwitchOffset, getDottedClassConstantOperand, getFieldDescriptorOperand, getIntConstant, getLongConstant, getMaxPC, getMethodDescriptorOperand, getNameConstantOperand, getNextCodeByte, getNextOpcode, getNextPC, getOpcode, getPC, getPrevOpcode, getRefConstantOperand, getRefFieldIsStatic, getRegisterOperand, getSigConstantOperand, getStringConstantOperand, getSwitchLabels, getSwitchOffsets, getXClassOperand, getXFieldOperand, getXMethodOperand, isBranch, isMethodCall, isRegisterLoad, isRegisterStore, isRegisterStore, isReturn, isShift, isSwitch, isWideOpcode, printOpCode, sawBranchTo, sawClass, sawDouble, sawField, sawFloat, sawIMethod, sawInt, sawLong, sawMethod, sawRegister, sawString, visit

    Methods inherited from class edu.umd.cs.findbugs.visitclass.AnnotationVisitor

    getAnnotationParameterAsEnum, getAnnotationParameterAsString, getAnnotationParameterAsStringArray, visitAnnotation, visitAnnotation, visitParameterAnnotation, 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, getMethodVisitOrder, getNumberArguments, getNumberMethodArguments, getPackageName, getSizeOfSurroundingTryBlock, getSizeOfSurroundingTryBlock, getSourceFile, getStringFromIndex, getSuperclassName, getSurroundingCaughtExceptions, getSurroundingCaughtExceptions, getSurroundingCaughtExceptionTypes, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitBootstrapMethods, visitConstantInvokeDynamic, visitConstantMethodHandle, visitConstantMethodType, visitConstantModule, visitConstantPackage, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitMethodParameters, visitParameterAnnotationEntry, visitStackMap, visitStackMapEntry

    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, visit, visitCodeException, visitConstantClass, visitConstantDouble, visitConstantFieldref, visitConstantFloat, visitConstantInteger, visitConstantInterfaceMethodref, visitConstantLong, visitConstantMethodref, visitConstantNameAndType, visitConstantString, visitConstantUtf8, visitConstantValue, visitDeprecated, visitExceptionTable, visitField, visitInnerClass, visitLineNumber, visitLocalVariable, visitLocalVariableTypeTable, visitMethod, visitSignature, visitSourceFile, visitSynthetic, visitUnknown

    Methods inherited from class java.lang.Object

    equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    Methods inherited from interface org.apache.bcel.classfile.Visitor

    visitConstantDynamic, visitMethodParameter, visitModule, visitModuleExports, visitModuleMainClass, visitModuleOpens, visitModulePackages, visitModuleProvides, visitModuleRequires, visitNestHost, visitNestMembers, visitRecord, visitRecordComponent, visitStackMapType

  • Field Details

    • branchInstructions

      private static final BitSet branchInstructions

    • binaryOps

      private static final BitSet binaryOps

    • bugReporter

      private final edu.umd.cs.findbugs.BugReporter bugReporter

    • branchTargets

      private BitSet branchTargets

    • catchTargets

      private BitSet catchTargets

    • stack

      private edu.umd.cs.findbugs.OpcodeStack stack

    • state

      private UnnecessaryStoreBeforeReturn.State state

    • storeReg

      private int storeReg

  • Constructor Details

    • UnnecessaryStoreBeforeReturn

      public UnnecessaryStoreBeforeReturn(edu.umd.cs.findbugs.BugReporter bugReporter)
      constructs a USBR detector given the reporter to report bugs on
      Parameters:
      bugReporter - the sync of bug reports

  • Method Details

    • visitClassContext

      public void visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)
      implements the visitor to create and clear the branchTargets
      Specified by:
      visitClassContext in interface edu.umd.cs.findbugs.Detector
      Overrides:
      visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector
      Parameters:
      classContext - the context object for the currently parsed class

    • visitCode

      public void visitCode(org.apache.bcel.classfile.Code obj)
      implements the visitor to make sure method returns a value, and then clears the targets
      Specified by:
      visitCode in interface org.apache.bcel.classfile.Visitor
      Overrides:
      visitCode in class edu.umd.cs.findbugs.visitclass.PreorderVisitor
      Parameters:
      obj - the context object of the currently parsed code block

    • sawOpcode

      public void sawOpcode(int seen)
      implements the visitor to look for store of registers immediately before returns of that register
      Overrides:
      sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode
      Parameters:
      seen - the opcode of the currently parsed instruction

    • lookForStore

      private boolean lookForStore(int seen)
      checks if the current opcode is a store, if so saves the register
      Parameters:
      seen - the opcode of the currently parsed instruction
      Returns:
      if a store was seen

    • lookForLoad

      private boolean lookForLoad(int seen)
      looks for a load of the register that was just stored
      Parameters:
      seen - the opcode of the currently parsed instruction
      Returns:
      if the load was seen

    • processBinOp

      private int processBinOp(int seen)
      looks for instructions that are binary operators, and if it is saves the left hand side register (if it exists) in the userValue.
      Parameters:
      seen - the opcode of the currently parsed instruction
      Returns:
      the lhs register number if it exists or -1