/* * Bytecode Analysis Framework * Copyright (C) 2003-2005 University of Maryland * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package edu.umd.cs.findbugs.ba; import org.apache.bcel.Constants; import org.apache.bcel.generic.*; import edu.umd.cs.findbugs.bcel.generic.NONNULL2Z; import edu.umd.cs.findbugs.bcel.generic.NULL2Z; /** * A common base class for frame modeling visitors. This class provides a * default implementation which copies values between frame slots whenever * appropriate. For example, its handler for the ALOAD bytecode will get the * value from the referenced local in the frame and push it onto the stack. * Bytecodes which do something other than copying values are modeled by popping * values as appropriate, and pushing the "default" value onto the stack for * each stack slot produced, where the default value is the one returned by the * getDefaultValue() method. * <p/> * <p> * Subclasses should override the visit methods for any bytecode instructions * which require special handling. * </p> * <p> * Users of AbstractFrameModelingVisitors should call the analyzeInstruction() * method instead of directly using the accept() method of the instruction. This * allows a checked DataflowAnalysisException to be thrown when invalid bytecode * is detected. E.g., stack underflows. * </p> * * @author David Hovemeyer * @see Frame * @see DataflowAnalysis */ public abstract class AbstractFrameModelingVisitor<Value, FrameType extends Frame<Value>> implements Visitor { private FrameType frame; private Location location; protected ConstantPoolGen cpg; /** * Constructor. * * @param cpg * the ConstantPoolGen of the method to be analyzed */ public AbstractFrameModelingVisitor(ConstantPoolGen cpg) { this.frame = null; this.cpg = cpg; } /** * Analyze the given Instruction. * * @param ins * the Instruction * @throws DataflowAnalysisException * if an error occurs analyzing the instruction; in most cases, * this indicates that the bytecode for the method being * analyzed is invalid */ public void analyzeInstruction(Instruction ins) throws DataflowAnalysisException { if (frame.isValid()) try { ins.accept(this); } catch (InvalidBytecodeException e) { System.out.println("Could not analyze " + ins + " frame is " + frame); e.printStackTrace(System.out); throw new DataflowAnalysisException("Invalid bytecode", e); } } /** * Get the ConstantPoolGen for the method. */ public ConstantPoolGen getCPG() { return cpg; } /** * Set the frame and Location for the instruction about to be modeled. * * @param frame * the Frame * @param location * the Location */ public void setFrameAndLocation(FrameType frame, Location location) { this.frame = frame; this.location = location; } /** * Get the frame. * * @return the Frame object */ public FrameType getFrame() { return frame; } /** * Get the Location. * * @return the Location */ public Location getLocation() { return location; } /** * Produce a "default" value. This is what is pushed onto the stack by the * handleNormalInstruction() method for instructions which produce stack * values. */ public abstract Value getDefaultValue(); /** * Get the number of words consumed by given instruction. */ public int getNumWordsConsumed(Instruction ins) { int numWordsConsumed = ins.consumeStack(cpg); if (numWordsConsumed == Constants.UNPREDICTABLE) throw new InvalidBytecodeException("Unpredictable stack consumption"); return numWordsConsumed; } /** * Get the number of words produced by given instruction. */ public int getNumWordsProduced(Instruction ins) { int numWordsProduced = ins.produceStack(cpg); if (numWordsProduced == Constants.UNPREDICTABLE) throw new InvalidBytecodeException("Unpredictable stack productions"); return numWordsProduced; } /** * This is called for illegal bytecodes. * * @throws InvalidBytecodeException */ private void illegalBytecode(Instruction ins) { throw new InvalidBytecodeException("Illegal bytecode: " + ins); } /* * ---------------------------------------------------------------------- * Empty visit methods * ---------------------------------------------------------------------- */ public void visitStackInstruction(StackInstruction obj) { } public void visitLocalVariableInstruction(LocalVariableInstruction obj) { } public void visitBranchInstruction(BranchInstruction obj) { } public void visitLoadClass(LoadClass obj) { } public void visitFieldInstruction(FieldInstruction obj) { } public void visitIfInstruction(IfInstruction obj) { } /** To allow for calls to visitNULL2Z and visitNONNULL2Z, this method is made final. * If you want to override it, override visitConversionInstruction2 instead. */ public final void visitConversionInstruction(ConversionInstruction obj) { visitConversionInstruction2(obj); if (obj instanceof NULL2Z) visitNULL2Z((NULL2Z) obj); else if (obj instanceof NONNULL2Z) visitNONNULL2Z((NONNULL2Z) obj); } public final void visitConversionInstruction2(ConversionInstruction obj) { } public void visitPopInstruction(PopInstruction obj) { } public void visitJsrInstruction(JsrInstruction obj) { } public void visitGotoInstruction(GotoInstruction obj) { } public void visitStoreInstruction(StoreInstruction obj) { } public void visitTypedInstruction(TypedInstruction obj) { } public void visitSelect(Select obj) { } public void visitUnconditionalBranch(UnconditionalBranch obj) { } public void visitPushInstruction(PushInstruction obj) { } public void visitArithmeticInstruction(ArithmeticInstruction obj) { } public void visitCPInstruction(CPInstruction obj) { } public void visitInvokeInstruction(InvokeInstruction obj) { } public void visitArrayInstruction(ArrayInstruction obj) { } public void visitAllocationInstruction(AllocationInstruction obj) { } public void visitReturnInstruction(ReturnInstruction obj) { } public void visitFieldOrMethod(FieldOrMethod obj) { } public void visitConstantPushInstruction(ConstantPushInstruction obj) { } public void visitExceptionThrower(ExceptionThrower obj) { } public void visitLoadInstruction(LoadInstruction obj) { } public void visitVariableLengthInstruction(VariableLengthInstruction obj) { } public void visitStackProducer(StackProducer obj) { } public void visitStackConsumer(StackConsumer obj) { } /* * ---------------------------------------------------------------------- * General instruction handlers * ---------------------------------------------------------------------- */ /** * Handler for all instructions which pop values from the stack and store * them in a local variable. Note that two locals are stored into for long * and double stores. */ public void handleStoreInstruction(StoreInstruction obj) { try { int numConsumed = obj.consumeStack(cpg); if (numConsumed == Constants.UNPREDICTABLE) throw new InvalidBytecodeException("Unpredictable stack consumption"); int index = obj.getIndex(); // Store values into consecutive locals corresponding // to the order in which the values appeared on the stack. while (numConsumed-- > 0) { Value value = frame.popValue(); frame.setValue(index++, value); } } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } /** * Handler for all instructions which load values from a local variable and * push them on the stack. Note that two locals are loaded for long and * double loads. */ public void handleLoadInstruction(LoadInstruction obj) { int numProduced = obj.produceStack(cpg); if (numProduced == Constants.UNPREDICTABLE) throw new InvalidBytecodeException("Unpredictable stack production"); int index = obj.getIndex() + numProduced; // Load values from locals in reverse order. // This restores them to the stack in a way consistent // with visitStoreInstruction(). while (numProduced-- > 0) { Value value = frame.getValue(--index); frame.pushValue(value); } } /** * This is called to handle any instruction which does not simply copy * values between stack slots. The default value is pushed (if the * instruction is a stack producer). */ public void handleNormalInstruction(Instruction ins) { modelNormalInstruction(ins, getNumWordsConsumed(ins), getNumWordsProduced(ins)); } /** * Model the stack for instructions handled by handleNormalInstruction(). * Subclasses may override to provide analysis-specific behavior. * * @param ins * the Instruction to model * @param numWordsConsumed * number of stack words consumed * @param numWordsProduced * number of stack words produced */ public void modelNormalInstruction(Instruction ins, int numWordsConsumed, int numWordsProduced) { modelInstruction(ins, numWordsConsumed, numWordsProduced, getDefaultValue()); } /** * Primitive to model the stack effect of a single instruction, explicitly * specifying the value to be pushed on the stack. * * @param ins * the Instruction to model * @param numWordsConsumed * number of stack words consumed * @param numWordsProduced * number of stack words produced * @param pushValue * value to push on the stack */ public void modelInstruction(Instruction ins, int numWordsConsumed, int numWordsProduced, Value pushValue) { if (frame.getStackDepth() < numWordsConsumed) { try { throw new IllegalArgumentException(" asked to pop " + numWordsConsumed + " stack elements but only " + frame.getStackDepth() + " elements remain in " + frame + " while processing " + ins); } catch (Exception e) { throw new IllegalArgumentException(" asked to pop " + numWordsConsumed + " stack elements but only " + frame.getStackDepth() + " elements remain while processing " + ins); } } try { while (numWordsConsumed-- > 0) frame.popValue(); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException("Not enough values on the stack", e); } while (numWordsProduced-- > 0) frame.pushValue(pushValue); } /* * ---------------------------------------------------------------------- * Visit methods for scalar STORE instructions * ---------------------------------------------------------------------- */ public void visitASTORE(ASTORE obj) { handleStoreInstruction(obj); } public void visitDSTORE(DSTORE obj) { handleStoreInstruction(obj); } public void visitFSTORE(FSTORE obj) { handleStoreInstruction(obj); } public void visitISTORE(ISTORE obj) { handleStoreInstruction(obj); } public void visitLSTORE(LSTORE obj) { handleStoreInstruction(obj); } /* * ---------------------------------------------------------------------- * Visit methods for scalar LOAD instructions * ---------------------------------------------------------------------- */ public void visitALOAD(ALOAD obj) { handleLoadInstruction(obj); } public void visitDLOAD(DLOAD obj) { handleLoadInstruction(obj); } public void visitFLOAD(FLOAD obj) { handleLoadInstruction(obj); } public void visitILOAD(ILOAD obj) { handleLoadInstruction(obj); } public void visitLLOAD(LLOAD obj) { handleLoadInstruction(obj); } /* * ---------------------------------------------------------------------- * Visit methods for POP, DUP, and SWAP instructions * ---------------------------------------------------------------------- */ public void visitPOP(POP obj) { handleNormalInstruction(obj); } public void visitPOP2(POP2 obj) { handleNormalInstruction(obj); } public void visitDUP(DUP obj) { try { Value value = frame.popValue(); frame.pushValue(value); frame.pushValue(value); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitDUP_X1(DUP_X1 obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); frame.pushValue(value1); frame.pushValue(value2); frame.pushValue(value1); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitDUP_X2(DUP_X2 obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); Value value3 = frame.popValue(); frame.pushValue(value1); frame.pushValue(value3); frame.pushValue(value2); frame.pushValue(value1); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitDUP2(DUP2 obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); frame.pushValue(value2); frame.pushValue(value1); frame.pushValue(value2); frame.pushValue(value1); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitDUP2_X1(DUP2_X1 obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); Value value3 = frame.popValue(); frame.pushValue(value2); frame.pushValue(value1); frame.pushValue(value3); frame.pushValue(value2); frame.pushValue(value1); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitDUP2_X2(DUP2_X2 obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); Value value3 = frame.popValue(); Value value4 = frame.popValue(); frame.pushValue(value2); frame.pushValue(value1); frame.pushValue(value4); frame.pushValue(value3); frame.pushValue(value2); frame.pushValue(value1); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } public void visitSWAP(SWAP obj) { try { Value value1 = frame.popValue(); Value value2 = frame.popValue(); frame.pushValue(value1); frame.pushValue(value2); } catch (DataflowAnalysisException e) { throw new InvalidBytecodeException(e.toString()); } } /* * ---------------------------------------------------------------------- * Illegal bytecodes * ---------------------------------------------------------------------- */ public void visitIMPDEP1(IMPDEP1 obj) { illegalBytecode(obj); } public void visitIMPDEP2(IMPDEP2 obj) { illegalBytecode(obj); } public void visitBREAKPOINT(BREAKPOINT obj) { illegalBytecode(obj); } /* * ---------------------------------------------------------------------- * Bytecodes that have "default" semantics * ---------------------------------------------------------------------- */ public void visitACONST_NULL(ACONST_NULL obj) { handleNormalInstruction(obj); } public void visitGETSTATIC(GETSTATIC obj) { handleNormalInstruction(obj); } public void visitIF_ICMPLT(IF_ICMPLT obj) { handleNormalInstruction(obj); } public void visitMONITOREXIT(MONITOREXIT obj) { handleNormalInstruction(obj); } public void visitIFLT(IFLT obj) { handleNormalInstruction(obj); } public void visitBASTORE(BASTORE obj) { handleNormalInstruction(obj); } public void visitCHECKCAST(CHECKCAST obj) { handleNormalInstruction(obj); } public void visitFCMPG(FCMPG obj) { handleNormalInstruction(obj); } public void visitI2F(I2F obj) { handleNormalInstruction(obj); } public void visitATHROW(ATHROW obj) { handleNormalInstruction(obj); } public void visitDCMPL(DCMPL obj) { handleNormalInstruction(obj); } public void visitARRAYLENGTH(ARRAYLENGTH obj) { handleNormalInstruction(obj); } public void visitINVOKESTATIC(INVOKESTATIC obj) { handleNormalInstruction(obj); } public void visitLCONST(LCONST obj) { handleNormalInstruction(obj); } public void visitDREM(DREM obj) { handleNormalInstruction(obj); } public void visitIFGE(IFGE obj) { handleNormalInstruction(obj); } public void visitCALOAD(CALOAD obj) { handleNormalInstruction(obj); } public void visitLASTORE(LASTORE obj) { handleNormalInstruction(obj); } public void visitI2D(I2D obj) { handleNormalInstruction(obj); } public void visitDADD(DADD obj) { handleNormalInstruction(obj); } public void visitINVOKESPECIAL(INVOKESPECIAL obj) { handleNormalInstruction(obj); } public void visitIAND(IAND obj) { handleNormalInstruction(obj); } public void visitPUTFIELD(PUTFIELD obj) { handleNormalInstruction(obj); } public void visitDCONST(DCONST obj) { handleNormalInstruction(obj); } public void visitNEW(NEW obj) { handleNormalInstruction(obj); } public void visitIFNULL(IFNULL obj) { handleNormalInstruction(obj); } public void visitLSUB(LSUB obj) { handleNormalInstruction(obj); } public void visitL2I(L2I obj) { handleNormalInstruction(obj); } public void visitISHR(ISHR obj) { handleNormalInstruction(obj); } public void visitTABLESWITCH(TABLESWITCH obj) { handleNormalInstruction(obj); } public void visitIINC(IINC obj) { handleNormalInstruction(obj); } public void visitDRETURN(DRETURN obj) { handleNormalInstruction(obj); } public void visitDASTORE(DASTORE obj) { handleNormalInstruction(obj); } public void visitIALOAD(IALOAD obj) { handleNormalInstruction(obj); } public void visitDDIV(DDIV obj) { handleNormalInstruction(obj); } public void visitIF_ICMPGE(IF_ICMPGE obj) { handleNormalInstruction(obj); } public void visitLAND(LAND obj) { handleNormalInstruction(obj); } public void visitIDIV(IDIV obj) { handleNormalInstruction(obj); } public void visitLOR(LOR obj) { handleNormalInstruction(obj); } public void visitCASTORE(CASTORE obj) { handleNormalInstruction(obj); } public void visitFREM(FREM obj) { handleNormalInstruction(obj); } public void visitLDC(LDC obj) { handleNormalInstruction(obj); } public void visitBIPUSH(BIPUSH obj) { handleNormalInstruction(obj); } public void visitF2L(F2L obj) { handleNormalInstruction(obj); } public void visitFMUL(FMUL obj) { handleNormalInstruction(obj); } public void visitJSR(JSR obj) { handleNormalInstruction(obj); } public void visitFSUB(FSUB obj) { handleNormalInstruction(obj); } public void visitSASTORE(SASTORE obj) { handleNormalInstruction(obj); } public void visitRETURN(RETURN obj) { handleNormalInstruction(obj); } public void visitDALOAD(DALOAD obj) { handleNormalInstruction(obj); } public void visitSIPUSH(SIPUSH obj) { handleNormalInstruction(obj); } public void visitDSUB(DSUB obj) { handleNormalInstruction(obj); } public void visitL2F(L2F obj) { handleNormalInstruction(obj); } public void visitIF_ICMPGT(IF_ICMPGT obj) { handleNormalInstruction(obj); } public void visitF2D(F2D obj) { handleNormalInstruction(obj); } public void visitI2L(I2L obj) { handleNormalInstruction(obj); } public void visitIF_ACMPNE(IF_ACMPNE obj) { handleNormalInstruction(obj); } public void visitNULL2Z(NULL2Z obj) { handleNormalInstruction(obj); } public void visitNONNULL2Z(NONNULL2Z obj) { handleNormalInstruction(obj); } public void visitI2S(I2S obj) { handleNormalInstruction(obj); } public void visitIFEQ(IFEQ obj) { handleNormalInstruction(obj); } public void visitIOR(IOR obj) { handleNormalInstruction(obj); } public void visitIREM(IREM obj) { handleNormalInstruction(obj); } public void visitIASTORE(IASTORE obj) { handleNormalInstruction(obj); } public void visitNEWARRAY(NEWARRAY obj) { handleNormalInstruction(obj); } public void visitINVOKEINTERFACE(INVOKEINTERFACE obj) { handleNormalInstruction(obj); } public void visitINEG(INEG obj) { handleNormalInstruction(obj); } public void visitLCMP(LCMP obj) { handleNormalInstruction(obj); } public void visitJSR_W(JSR_W obj) { handleNormalInstruction(obj); } public void visitMULTIANEWARRAY(MULTIANEWARRAY obj) { handleNormalInstruction(obj); } public void visitSALOAD(SALOAD obj) { handleNormalInstruction(obj); } public void visitIFNONNULL(IFNONNULL obj) { handleNormalInstruction(obj); } public void visitDMUL(DMUL obj) { handleNormalInstruction(obj); } public void visitIFNE(IFNE obj) { handleNormalInstruction(obj); } public void visitIF_ICMPLE(IF_ICMPLE obj) { handleNormalInstruction(obj); } public void visitLDC2_W(LDC2_W obj) { handleNormalInstruction(obj); } public void visitGETFIELD(GETFIELD obj) { handleNormalInstruction(obj); } public void visitLADD(LADD obj) { handleNormalInstruction(obj); } public void visitNOP(NOP obj) { handleNormalInstruction(obj); } public void visitFALOAD(FALOAD obj) { handleNormalInstruction(obj); } public void visitINSTANCEOF(INSTANCEOF obj) { handleNormalInstruction(obj); } public void visitIFLE(IFLE obj) { handleNormalInstruction(obj); } public void visitLXOR(LXOR obj) { handleNormalInstruction(obj); } public void visitLRETURN(LRETURN obj) { handleNormalInstruction(obj); } public void visitFCONST(FCONST obj) { handleNormalInstruction(obj); } public void visitIUSHR(IUSHR obj) { handleNormalInstruction(obj); } public void visitBALOAD(BALOAD obj) { handleNormalInstruction(obj); } public void visitIF_ACMPEQ(IF_ACMPEQ obj) { handleNormalInstruction(obj); } public void visitMONITORENTER(MONITORENTER obj) { handleNormalInstruction(obj); } public void visitLSHL(LSHL obj) { handleNormalInstruction(obj); } public void visitDCMPG(DCMPG obj) { handleNormalInstruction(obj); } public void visitD2L(D2L obj) { handleNormalInstruction(obj); } public void visitL2D(L2D obj) { handleNormalInstruction(obj); } public void visitRET(RET obj) { handleNormalInstruction(obj); } public void visitIFGT(IFGT obj) { handleNormalInstruction(obj); } public void visitIXOR(IXOR obj) { handleNormalInstruction(obj); } public void visitINVOKEVIRTUAL(INVOKEVIRTUAL obj) { handleNormalInstruction(obj); } public void visitFASTORE(FASTORE obj) { handleNormalInstruction(obj); } public void visitIRETURN(IRETURN obj) { handleNormalInstruction(obj); } public void visitIF_ICMPNE(IF_ICMPNE obj) { handleNormalInstruction(obj); } public void visitLDIV(LDIV obj) { handleNormalInstruction(obj); } public void visitPUTSTATIC(PUTSTATIC obj) { handleNormalInstruction(obj); } public void visitAALOAD(AALOAD obj) { handleNormalInstruction(obj); } public void visitD2I(D2I obj) { handleNormalInstruction(obj); } public void visitIF_ICMPEQ(IF_ICMPEQ obj) { handleNormalInstruction(obj); } public void visitAASTORE(AASTORE obj) { handleNormalInstruction(obj); } public void visitARETURN(ARETURN obj) { handleNormalInstruction(obj); } public void visitFNEG(FNEG obj) { handleNormalInstruction(obj); } public void visitGOTO_W(GOTO_W obj) { handleNormalInstruction(obj); } public void visitD2F(D2F obj) { handleNormalInstruction(obj); } public void visitGOTO(GOTO obj) { handleNormalInstruction(obj); } public void visitISUB(ISUB obj) { handleNormalInstruction(obj); } public void visitF2I(F2I obj) { handleNormalInstruction(obj); } public void visitDNEG(DNEG obj) { handleNormalInstruction(obj); } public void visitICONST(ICONST obj) { handleNormalInstruction(obj); } public void visitFDIV(FDIV obj) { handleNormalInstruction(obj); } public void visitI2B(I2B obj) { handleNormalInstruction(obj); } public void visitLNEG(LNEG obj) { handleNormalInstruction(obj); } public void visitLREM(LREM obj) { handleNormalInstruction(obj); } public void visitIMUL(IMUL obj) { handleNormalInstruction(obj); } public void visitIADD(IADD obj) { handleNormalInstruction(obj); } public void visitLSHR(LSHR obj) { handleNormalInstruction(obj); } public void visitLOOKUPSWITCH(LOOKUPSWITCH obj) { handleNormalInstruction(obj); } public void visitFCMPL(FCMPL obj) { handleNormalInstruction(obj); } public void visitI2C(I2C obj) { handleNormalInstruction(obj); } public void visitLMUL(LMUL obj) { handleNormalInstruction(obj); } public void visitLUSHR(LUSHR obj) { handleNormalInstruction(obj); } public void visitISHL(ISHL obj) { handleNormalInstruction(obj); } public void visitLALOAD(LALOAD obj) { handleNormalInstruction(obj); } public void visitANEWARRAY(ANEWARRAY obj) { handleNormalInstruction(obj); } public void visitFRETURN(FRETURN obj) { handleNormalInstruction(obj); } public void visitFADD(FADD obj) { handleNormalInstruction(obj); } } // vim:ts=4