Class FieldCouldBeLocal

  • All Implemented Interfaces:
    edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, edu.umd.cs.findbugs.visitclass.Constants2, org.apache.bcel.classfile.Visitor, org.apache.bcel.Constants

    public class FieldCouldBeLocal
    extends edu.umd.cs.findbugs.BytecodeScanningDetector
    finds fields that are used in a locals only fashion, specifically private fields that are accessed first in each method with a store vs. a load.
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      private static class  FieldCouldBeLocal.BlockState
      holds the parse state of the current basic block, and what fields are left to be checked the fields that are left to be checked are a reference from the parent block and a new collection is created on first write to the set to reduce memory concerns.
      private static class  FieldCouldBeLocal.FieldInfo
      holds information about a field and it's first usage
      private static class  FieldCouldBeLocal.FieldModifier
      a visitor that determines what methods write to what fields
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private edu.umd.cs.findbugs.BugReporter bugReporter  
      private edu.umd.cs.findbugs.ba.CFG cfg  
      private edu.umd.cs.findbugs.ba.ClassContext clsContext  
      private java.lang.String clsName  
      private java.lang.String clsSig  
      private org.apache.bcel.generic.ConstantPoolGen cpg  
      private java.util.Map<java.lang.String,​FieldCouldBeLocal.FieldInfo> localizableFields  
      private java.util.Map<java.lang.String,​java.util.Set<java.lang.String>> methodFieldModifiers  
      private java.util.BitSet visitedBlocks  
      • 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 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_SYPER, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACCESS_NAMES, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ANEWARRAY_QUICK, APPEND_FRAME, APPEND_FRAME_MAX, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, ATTR_ANNOTATION_DEFAULT, ATTR_CODE, ATTR_CONSTANT_VALUE, ATTR_DEPRECATED, ATTR_ENCLOSING_METHOD, ATTR_EXCEPTIONS, ATTR_INNER_CLASSES, ATTR_LINE_NUMBER_TABLE, ATTR_LOCAL_VARIABLE_TABLE, ATTR_LOCAL_VARIABLE_TYPE_TABLE, ATTR_PMG, ATTR_RUNTIME_VISIBLE_ANNOTATIONS, ATTR_RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_SIGNATURE, ATTR_SOURCE_FILE, ATTR_STACK_MAP, ATTR_STACK_MAP_TABLE, ATTR_SYNTHETIC, ATTR_UNKNOWN, ATTRIBUTE_NAMES, BALOAD, BASTORE, BIPUSH, BREAKPOINT, CALOAD, CASTORE, CHECKCAST, CHECKCAST_QUICK, CHOP_FRAME, CHOP_FRAME_MAX, CLASS_TYPE_NAMES, CONSTANT_Class, CONSTANT_Double, CONSTANT_Fieldref, CONSTANT_Float, CONSTANT_Integer, CONSTANT_InterfaceMethodref, CONSTANT_InvokeDynamic, CONSTANT_Long, CONSTANT_MethodHandle, CONSTANT_Methodref, CONSTANT_MethodType, 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, FULL_FRAME, 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, INVOKEDYNAMIC, 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, MAJOR_1_6, MAJOR_1_7, MAJOR_1_8, 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, MINOR_1_6, MINOR_1_7, MINOR_1_8, 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, SAME_FRAME, SAME_FRAME_EXTENDED, SAME_FRAME_MAX, SAME_LOCALS_1_STACK_ITEM_FRAME, SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED, SAME_LOCALS_1_STACK_ITEM_FRAME_MAX, 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
      • Fields inherited from interface edu.umd.cs.findbugs.Priorities

        EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY
    • Constructor Summary

      Constructors 
      Constructor Description
      FieldCouldBeLocal​(edu.umd.cs.findbugs.BugReporter bugReporter)
      constructs a FCBL detector given the reporter to report bugs on.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private void buildMethodFieldModifiers​(edu.umd.cs.findbugs.ba.ClassContext classContext)
      builds up the method to field map of what method write to which fields this is one recursively so that if method A calls method B, and method B writes to field C, then A modifies F.
      private void checkBlock​(edu.umd.cs.findbugs.ba.BasicBlock startBB, java.util.Set<java.lang.String> uncheckedFields)
      looks in this basic block for the first access to the fields in uncheckedFields.
      private boolean prescreen​(org.apache.bcel.classfile.Method method)
      looks for methods that contain a GETFIELD or PUTFIELD opcodes
      void sawOpcode​(int seen)
      implements the visitor to add SourceLineAnnotations for fields in constructors and static initializers.
      void visitClassContext​(edu.umd.cs.findbugs.ba.ClassContext classContext)
      overrides the visitor to collect localizable fields, and then report those that survive all method checks.
      void visitCode​(org.apache.bcel.classfile.Code obj)
      implements the visitor to pass through constructors and static initializers to the byte code scanning code.
      void visitMethod​(org.apache.bcel.classfile.Method obj)
      overrides the visitor to navigate basic blocks looking for all first usages of fields, removing those that are read from first.
      • 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

        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, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitStackMapTable, visitStackMapTableEntry
      • 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, visitSignature, visitSourceFile, visitStackMap, visitStackMapEntry, visitSynthetic, visitUnknown
      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • bugReporter

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

        private edu.umd.cs.findbugs.ba.ClassContext clsContext
      • cfg

        private edu.umd.cs.findbugs.ba.CFG cfg
      • cpg

        private org.apache.bcel.generic.ConstantPoolGen cpg
      • visitedBlocks

        private java.util.BitSet visitedBlocks
      • methodFieldModifiers

        private java.util.Map<java.lang.String,​java.util.Set<java.lang.String>> methodFieldModifiers
      • clsName

        private java.lang.String clsName
      • clsSig

        private java.lang.String clsSig
    • Constructor Detail

      • FieldCouldBeLocal

        public FieldCouldBeLocal​(edu.umd.cs.findbugs.BugReporter bugReporter)
        constructs a FCBL detector given the reporter to report bugs on.
        Parameters:
        bugReporter - the sync of bug reports
    • Method Detail

      • visitClassContext

        public void visitClassContext​(edu.umd.cs.findbugs.ba.ClassContext classContext)
        overrides the visitor to collect localizable fields, and then report those that survive all method checks.
        Specified by:
        visitClassContext in interface edu.umd.cs.findbugs.Detector
        Overrides:
        visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector
        Parameters:
        classContext - the context object that holds the JavaClass parsed
      • visitMethod

        public void visitMethod​(org.apache.bcel.classfile.Method obj)
        overrides the visitor to navigate basic blocks looking for all first usages of fields, removing those that are read from first.
        Specified by:
        visitMethod in interface org.apache.bcel.classfile.Visitor
        Overrides:
        visitMethod in class edu.umd.cs.findbugs.visitclass.BetterVisitor
        Parameters:
        obj - the context object of the currently parsed method
      • prescreen

        private boolean prescreen​(org.apache.bcel.classfile.Method method)
        looks for methods that contain a GETFIELD or PUTFIELD opcodes
        Parameters:
        method - the context object of the current method
        Returns:
        if the class uses GETFIELD or PUTFIELD
      • visitCode

        public void visitCode​(org.apache.bcel.classfile.Code obj)
        implements the visitor to pass through constructors and static initializers to the byte code scanning code. These methods are not reported, but are used to build SourceLineAnnotations for fields, if accessed.
        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 attribute
      • sawOpcode

        public void sawOpcode​(int seen)
        implements the visitor to add SourceLineAnnotations for fields in constructors and static initializers.
        Overrides:
        sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode
        Parameters:
        seen - the opcode of the currently visited instruction
      • checkBlock

        private void checkBlock​(edu.umd.cs.findbugs.ba.BasicBlock startBB,
                                java.util.Set<java.lang.String> uncheckedFields)
        looks in this basic block for the first access to the fields in uncheckedFields. Once found the item is removed from uncheckedFields, and removed from localizableFields if the access is a GETFIELD. If any unchecked fields remain, this method is recursively called on all outgoing edges of this basic block.
        Parameters:
        startBB - this basic block
        uncheckedFields - the list of fields to look for
      • buildMethodFieldModifiers

        private void buildMethodFieldModifiers​(edu.umd.cs.findbugs.ba.ClassContext classContext)
        builds up the method to field map of what method write to which fields this is one recursively so that if method A calls method B, and method B writes to field C, then A modifies F.
        Parameters:
        classContext - the context object of the currently parsed class