com.mebigfatguy.fbcontrib.detect

Class FieldCouldBeLocal

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.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 and 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 and 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 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_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

Constructor Summary

Constructors

Constructor and Description
FieldCouldBeLocal(edu.umd.cs.findbugs.BugReporter bugReporter) constructs a FCBL detector given the reporter to report bugs on.

Method Summary

Modifier and Type	Method and 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

localizableFields

private java.util.Map<java.lang.String,FieldCouldBeLocal.FieldInfo> localizableFields

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