| /* |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification |
| * of Java bytecode. |
| * |
| * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| * |
| * This program 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 General Public License for |
| * more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| package proguard.classfile.editor; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.attribute.*; |
| import proguard.classfile.attribute.preverification.*; |
| import proguard.classfile.attribute.preverification.visitor.*; |
| import proguard.classfile.attribute.visitor.*; |
| import proguard.classfile.instruction.*; |
| import proguard.classfile.instruction.visitor.InstructionVisitor; |
| import proguard.classfile.util.SimplifiedVisitor; |
| |
| /** |
| * This AttributeVisitor accumulates instructions and exceptions, and then |
| * copies them into code attributes that it visits. |
| * |
| * @author Eric Lafortune |
| */ |
| public class CodeAttributeComposer |
| extends SimplifiedVisitor |
| implements AttributeVisitor, |
| InstructionVisitor, |
| ExceptionInfoVisitor, |
| StackMapFrameVisitor, |
| VerificationTypeVisitor, |
| LineNumberInfoVisitor, |
| LocalVariableInfoVisitor, |
| LocalVariableTypeInfoVisitor |
| { |
| //* |
| private static final boolean DEBUG = false; |
| /*/ |
| public static boolean DEBUG = true; |
| //*/ |
| |
| |
| private static final int MAXIMUM_LEVELS = 32; |
| private static final int INVALID = -1; |
| |
| |
| private boolean allowExternalExceptionHandlers; |
| |
| private int maximumCodeLength; |
| private int codeLength; |
| private int exceptionTableLength; |
| private int level = -1; |
| |
| private byte[] code = new byte[ClassConstants.TYPICAL_CODE_LENGTH]; |
| private int[] oldInstructionOffsets = new int[ClassConstants.TYPICAL_CODE_LENGTH]; |
| |
| private final int[] codeFragmentOffsets = new int[MAXIMUM_LEVELS]; |
| private final int[] codeFragmentLengths = new int[MAXIMUM_LEVELS]; |
| private final int[][] instructionOffsetMap = new int[MAXIMUM_LEVELS][ClassConstants.TYPICAL_CODE_LENGTH + 1]; |
| |
| private ExceptionInfo[] exceptionTable = new ExceptionInfo[ClassConstants.TYPICAL_EXCEPTION_TABLE_LENGTH]; |
| |
| private int expectedStackMapFrameOffset; |
| |
| private final StackSizeUpdater stackSizeUpdater = new StackSizeUpdater(); |
| private final VariableSizeUpdater variableSizeUpdater = new VariableSizeUpdater(); |
| // private final InstructionWriter instructionWriter = new InstructionWriter(); |
| |
| |
| /** |
| * Creates a new CodeAttributeComposer that doesn't allow external exception |
| * handlers. |
| */ |
| public CodeAttributeComposer() |
| { |
| this(false); |
| } |
| |
| |
| /** |
| * Creates a new CodeAttributeComposer that optionally allows external |
| * exception handlers. |
| */ |
| public CodeAttributeComposer(boolean allowExternalExceptionHandlers) |
| { |
| this.allowExternalExceptionHandlers = allowExternalExceptionHandlers; |
| } |
| |
| |
| /** |
| * Starts a new code definition. |
| */ |
| public void reset() |
| { |
| maximumCodeLength = 0; |
| codeLength = 0; |
| exceptionTableLength = 0; |
| level = -1; |
| } |
| |
| |
| /** |
| * Starts a new code fragment. Branch instructions that are added are |
| * assumed to be relative within such code fragments. |
| * @param maximumCodeFragmentLength the maximum length of the code that will |
| * be added as part of this fragment. |
| */ |
| public void beginCodeFragment(int maximumCodeFragmentLength) |
| { |
| level++; |
| |
| if (level >= MAXIMUM_LEVELS) |
| { |
| throw new IllegalArgumentException("Maximum number of code fragment levels exceeded ["+level+"]"); |
| } |
| |
| // // TODO: Figure out some length. |
| // if (level == 0) |
| // { |
| // // Prepare for possible widening of instructions. |
| // instructionWriter.reset(2 * maximumCodeFragmentLength); |
| // } |
| |
| // Make sure there is sufficient space for adding the code fragment. |
| maximumCodeLength += maximumCodeFragmentLength; |
| |
| ensureCodeLength(maximumCodeLength); |
| |
| // Try to reuse the previous array for this code fragment. |
| if (instructionOffsetMap[level].length <= maximumCodeFragmentLength) |
| { |
| instructionOffsetMap[level] = new int[maximumCodeFragmentLength + 1]; |
| } |
| |
| // Initialize the offset map. |
| for (int index = 0; index <= maximumCodeFragmentLength; index++) |
| { |
| instructionOffsetMap[level][index] = INVALID; |
| } |
| |
| // Remember the location of the code fragment. |
| codeFragmentOffsets[level] = codeLength; |
| codeFragmentLengths[level] = maximumCodeFragmentLength; |
| } |
| |
| |
| /** |
| * Appends the given instruction with the given old offset. |
| * @param oldInstructionOffset the old offset of the instruction, to which |
| * branches and other references in the current |
| * code fragment are pointing. |
| * @param instruction the instruction to be appended. |
| */ |
| public void appendInstruction(int oldInstructionOffset, |
| Instruction instruction) |
| { |
| if (DEBUG) |
| { |
| println("["+codeLength+"] <- ", instruction.toString(oldInstructionOffset)); |
| } |
| |
| // Make sure the code array is large enough. |
| int newCodeLength = codeLength + instruction.length(codeLength); |
| |
| ensureCodeLength(newCodeLength); |
| |
| // Remember the old offset of the appended instruction. |
| oldInstructionOffsets[codeLength] = oldInstructionOffset; |
| |
| // Write the instruction. |
| // instruction.accept(null, |
| // null, |
| // new CodeAttribute(0, 0, 0, 0, code, 0, null, 0, null), |
| // codeLength, |
| // instructionWriter); |
| instruction.write(code, codeLength); |
| |
| // Fill out the new offset of the appended instruction. |
| instructionOffsetMap[level][oldInstructionOffset] = codeLength; |
| |
| // Continue appending at the next instruction offset. |
| codeLength = newCodeLength; |
| } |
| |
| |
| /** |
| * Appends the given label with the given old offset. |
| * @param oldInstructionOffset the old offset of the label, to which |
| * branches and other references in the current |
| * code fragment are pointing. |
| */ |
| public void appendLabel(int oldInstructionOffset) |
| { |
| if (DEBUG) |
| { |
| println("["+codeLength+"] <- ", "[" + oldInstructionOffset + "] (label)"); |
| } |
| |
| // Fill out the new offset of the appended instruction. |
| instructionOffsetMap[level][oldInstructionOffset] = codeLength; |
| } |
| |
| |
| /** |
| * Appends the given exception to the exception table. |
| * @param exceptionInfo the exception to be appended. |
| */ |
| public void appendException(ExceptionInfo exceptionInfo) |
| { |
| if (DEBUG) |
| { |
| print(" ", "Exception ["+exceptionInfo.u2startPC+" -> "+exceptionInfo.u2endPC+": "+exceptionInfo.u2handlerPC+"]"); |
| } |
| |
| // Remap the exception right away. |
| visitExceptionInfo(null, null, null, exceptionInfo); |
| |
| if (DEBUG) |
| { |
| System.out.println(" -> ["+exceptionInfo.u2startPC+" -> "+exceptionInfo.u2endPC+": "+exceptionInfo.u2handlerPC+"]"); |
| } |
| |
| // Don't add the exception if its instruction range is empty. |
| if (exceptionInfo.u2startPC == exceptionInfo.u2endPC) |
| { |
| if (DEBUG) |
| { |
| println(" ", " (not added because of empty instruction range)"); |
| } |
| |
| return; |
| } |
| |
| // Make sure there is sufficient space in the exception table. |
| if (exceptionTable.length <= exceptionTableLength) |
| { |
| ExceptionInfo[] newExceptionTable = new ExceptionInfo[exceptionTableLength+1]; |
| System.arraycopy(exceptionTable, 0, newExceptionTable, 0, exceptionTableLength); |
| exceptionTable = newExceptionTable; |
| } |
| |
| // Add the exception. |
| exceptionTable[exceptionTableLength++] = exceptionInfo; |
| } |
| |
| |
| /** |
| * Wraps up the current code fragment, continuing with the previous one on |
| * the stack. |
| */ |
| public void endCodeFragment() |
| { |
| if (level < 0) |
| { |
| throw new IllegalArgumentException("Code fragment not begun ["+level+"]"); |
| } |
| |
| // Remap the instructions of the code fragment. |
| int instructionOffset = codeFragmentOffsets[level]; |
| while (instructionOffset < codeLength) |
| { |
| // Get the next instruction. |
| Instruction instruction = InstructionFactory.create(code, instructionOffset); |
| |
| // Does this instruction still have to be remapped? |
| if (oldInstructionOffsets[instructionOffset] >= 0) |
| { |
| // Adapt the instruction for its new offset. |
| instruction.accept(null, null, null, instructionOffset, this); |
| |
| // Write the instruction back. |
| // instruction.accept(null, |
| // null, |
| // new CodeAttribute(0, 0, 0, 0, code, 0, null, 0, null), |
| // instructionOffset, |
| // instructionWriter); |
| instruction.write(code, instructionOffset); |
| |
| // Don't remap this instruction again. |
| oldInstructionOffsets[instructionOffset] = -1; |
| } |
| |
| // Continue remapping at the next instruction offset. |
| instructionOffset += instruction.length(instructionOffset); |
| } |
| |
| // Correct the estimated maximum code length, now that we know the |
| // actual length of this code fragment. |
| maximumCodeLength += codeLength - codeFragmentOffsets[level] - |
| codeFragmentLengths[level]; |
| |
| // Try to remap the exception handlers that couldn't be remapped before. |
| if (allowExternalExceptionHandlers) |
| { |
| for (int index = 0; index < exceptionTableLength; index++) |
| { |
| ExceptionInfo exceptionInfo = exceptionTable[index]; |
| |
| // Unmapped exception handlers are still negated. |
| int handlerPC = -exceptionInfo.u2handlerPC; |
| if (handlerPC > 0) |
| { |
| if (remappableInstructionOffset(handlerPC)) |
| { |
| exceptionInfo.u2handlerPC = remapInstructionOffset(handlerPC); |
| } |
| else if (level == 0) |
| { |
| throw new IllegalStateException("Couldn't remap exception handler offset ["+handlerPC+"]"); |
| } |
| } |
| } |
| } |
| |
| level--; |
| } |
| |
| |
| // Implementations for AttributeVisitor. |
| |
| public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} |
| |
| |
| public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) |
| { |
| if (DEBUG) |
| { |
| System.out.println("CodeAttributeComposer: putting results in ["+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)+"]"); |
| } |
| |
| if (level != -1) |
| { |
| throw new IllegalArgumentException("Code fragment not ended ["+level+"]"); |
| } |
| |
| level++; |
| |
| // Make sure the code attribute has sufficient space for the composed |
| // code. |
| if (codeAttribute.u4codeLength < codeLength) |
| { |
| codeAttribute.code = new byte[codeLength]; |
| } |
| |
| // Copy the composed code over into the code attribute. |
| codeAttribute.u4codeLength = codeLength; |
| System.arraycopy(code, 0, codeAttribute.code, 0, codeLength); |
| |
| // Remove exceptions with empty code blocks (done before). |
| //exceptionTableLength = |
| // removeEmptyExceptions(exceptionTable, exceptionTableLength); |
| |
| // Make sure the exception table has sufficient space for the composed |
| // exceptions. |
| if (codeAttribute.exceptionTable.length < exceptionTableLength) |
| { |
| codeAttribute.exceptionTable = new ExceptionInfo[exceptionTableLength]; |
| } |
| |
| // Copy the exception table. |
| codeAttribute.u2exceptionTableLength = exceptionTableLength; |
| System.arraycopy(exceptionTable, 0, codeAttribute.exceptionTable, 0, exceptionTableLength); |
| |
| // Update the maximum stack size and local variable frame size. |
| stackSizeUpdater.visitCodeAttribute(clazz, method, codeAttribute); |
| variableSizeUpdater.visitCodeAttribute(clazz, method, codeAttribute); |
| |
| // Remap the line number table and the local variable table. |
| codeAttribute.attributesAccept(clazz, method, this); |
| |
| // Remap the exception table. |
| //codeAttribute.exceptionsAccept(clazz, method, this); |
| |
| // Remove exceptions with empty code blocks (done before). |
| //codeAttribute.u2exceptionTableLength = |
| // removeEmptyExceptions(codeAttribute.exceptionTable, |
| // codeAttribute.u2exceptionTableLength); |
| |
| // // Make sure instructions are widened if necessary. |
| // instructionWriter.visitCodeAttribute(clazz, method, codeAttribute); |
| |
| level--; |
| } |
| |
| |
| public void visitStackMapAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, StackMapAttribute stackMapAttribute) |
| { |
| // Remap all stack map entries. |
| expectedStackMapFrameOffset = -1; |
| stackMapAttribute.stackMapFramesAccept(clazz, method, codeAttribute, this); |
| } |
| |
| |
| public void visitStackMapTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, StackMapTableAttribute stackMapTableAttribute) |
| { |
| // Remap all stack map table entries. |
| expectedStackMapFrameOffset = 0; |
| stackMapTableAttribute.stackMapFramesAccept(clazz, method, codeAttribute, this); |
| } |
| |
| |
| public void visitLineNumberTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LineNumberTableAttribute lineNumberTableAttribute) |
| { |
| // Remap all line number table entries. |
| lineNumberTableAttribute.lineNumbersAccept(clazz, method, codeAttribute, this); |
| |
| // Remove line numbers with empty code blocks. |
| lineNumberTableAttribute.u2lineNumberTableLength = |
| removeEmptyLineNumbers(lineNumberTableAttribute.lineNumberTable, |
| lineNumberTableAttribute.u2lineNumberTableLength, |
| codeAttribute.u4codeLength); |
| } |
| |
| |
| public void visitLocalVariableTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTableAttribute localVariableTableAttribute) |
| { |
| // Remap all local variable table entries. |
| localVariableTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this); |
| |
| // Remove local variables with empty code blocks. |
| localVariableTableAttribute.u2localVariableTableLength = |
| removeEmptyLocalVariables(localVariableTableAttribute.localVariableTable, |
| localVariableTableAttribute.u2localVariableTableLength, |
| codeAttribute.u2maxLocals); |
| } |
| |
| |
| public void visitLocalVariableTypeTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeTableAttribute localVariableTypeTableAttribute) |
| { |
| // Remap all local variable table entries. |
| localVariableTypeTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this); |
| |
| // Remove local variables with empty code blocks. |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength = |
| removeEmptyLocalVariableTypes(localVariableTypeTableAttribute.localVariableTypeTable, |
| localVariableTypeTableAttribute.u2localVariableTypeTableLength, |
| codeAttribute.u2maxLocals); |
| } |
| |
| |
| // Implementations for InstructionVisitor. |
| |
| public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} |
| |
| |
| public void visitBranchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, BranchInstruction branchInstruction) |
| { |
| // Adjust the branch offset. |
| branchInstruction.branchOffset = remapBranchOffset(offset, |
| branchInstruction.branchOffset); |
| } |
| |
| |
| public void visitAnySwitchInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SwitchInstruction switchInstruction) |
| { |
| // Adjust the default jump offset. |
| switchInstruction.defaultOffset = remapBranchOffset(offset, |
| switchInstruction.defaultOffset); |
| |
| // Adjust the jump offsets. |
| remapJumpOffsets(offset, |
| switchInstruction.jumpOffsets); |
| } |
| |
| |
| // Implementations for ExceptionInfoVisitor. |
| |
| public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo) |
| { |
| // Remap the code offsets. Note that the instruction offset map also has |
| // an entry for the first offset after the code, for u2endPC. |
| exceptionInfo.u2startPC = remapInstructionOffset(exceptionInfo.u2startPC); |
| exceptionInfo.u2endPC = remapInstructionOffset(exceptionInfo.u2endPC); |
| |
| // See if we can remap the handler right away. Unmapped exception |
| // handlers are negated, in order to mark them as external. |
| int handlerPC = exceptionInfo.u2handlerPC; |
| exceptionInfo.u2handlerPC = |
| !allowExternalExceptionHandlers || |
| remappableInstructionOffset(handlerPC) ? |
| remapInstructionOffset(handlerPC) : |
| -handlerPC; |
| } |
| |
| |
| // Implementations for StackMapFrameVisitor. |
| |
| public void visitAnyStackMapFrame(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrame stackMapFrame) |
| { |
| // Remap the stack map frame offset. |
| int stackMapFrameOffset = remapInstructionOffset(offset); |
| |
| int offsetDelta = stackMapFrameOffset; |
| |
| // Compute the offset delta if the frame is part of a stack map frame |
| // table (for JDK 6.0) instead of a stack map (for Java Micro Edition). |
| if (expectedStackMapFrameOffset >= 0) |
| { |
| offsetDelta -= expectedStackMapFrameOffset; |
| |
| expectedStackMapFrameOffset = stackMapFrameOffset + 1; |
| } |
| |
| stackMapFrame.u2offsetDelta = offsetDelta; |
| } |
| |
| |
| public void visitSameOneFrame(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SameOneFrame sameOneFrame) |
| { |
| // Remap the stack map frame offset. |
| visitAnyStackMapFrame(clazz, method, codeAttribute, offset, sameOneFrame); |
| |
| // Remap the verification type offset. |
| sameOneFrame.stackItemAccept(clazz, method, codeAttribute, offset, this); |
| } |
| |
| |
| public void visitMoreZeroFrame(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, MoreZeroFrame moreZeroFrame) |
| { |
| // Remap the stack map frame offset. |
| visitAnyStackMapFrame(clazz, method, codeAttribute, offset, moreZeroFrame); |
| |
| // Remap the verification type offsets. |
| moreZeroFrame.additionalVariablesAccept(clazz, method, codeAttribute, offset, this); |
| } |
| |
| |
| public void visitFullFrame(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, FullFrame fullFrame) |
| { |
| // Remap the stack map frame offset. |
| visitAnyStackMapFrame(clazz, method, codeAttribute, offset, fullFrame); |
| |
| // Remap the verification type offsets. |
| fullFrame.variablesAccept(clazz, method, codeAttribute, offset, this); |
| fullFrame.stackAccept(clazz, method, codeAttribute, offset, this); |
| } |
| |
| |
| // Implementations for VerificationTypeVisitor. |
| |
| public void visitAnyVerificationType(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VerificationType verificationType) {} |
| |
| |
| public void visitUninitializedType(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, UninitializedType uninitializedType) |
| { |
| // Remap the offset of the 'new' instruction. |
| uninitializedType.u2newInstructionOffset = remapInstructionOffset(uninitializedType.u2newInstructionOffset); |
| } |
| |
| |
| // Implementations for LineNumberInfoVisitor. |
| |
| public void visitLineNumberInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LineNumberInfo lineNumberInfo) |
| { |
| // Remap the code offset. |
| lineNumberInfo.u2startPC = remapInstructionOffset(lineNumberInfo.u2startPC); |
| } |
| |
| |
| // Implementations for LocalVariableInfoVisitor. |
| |
| public void visitLocalVariableInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableInfo localVariableInfo) |
| { |
| // Remap the code offset and length. |
| // TODO: The local variable frame might not be strictly preserved. |
| int startPC = remapInstructionOffset(localVariableInfo.u2startPC); |
| int endPC = remapInstructionOffset(localVariableInfo.u2startPC + localVariableInfo.u2length); |
| |
| localVariableInfo.u2startPC = startPC; |
| localVariableInfo.u2length = endPC - startPC; |
| } |
| |
| // Implementations for LocalVariableTypeInfoVisitor. |
| |
| public void visitLocalVariableTypeInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeInfo localVariableTypeInfo) |
| { |
| // Remap the code offset and length. |
| // TODO: The local variable frame might not be strictly preserved. |
| int startPC = remapInstructionOffset(localVariableTypeInfo.u2startPC); |
| int endPC = remapInstructionOffset(localVariableTypeInfo.u2startPC + localVariableTypeInfo.u2length); |
| |
| localVariableTypeInfo.u2startPC = startPC; |
| localVariableTypeInfo.u2length = endPC - startPC; |
| } |
| |
| |
| // Small utility methods. |
| |
| /** |
| * Make sure the code arrays have at least the given size. |
| */ |
| private void ensureCodeLength(int newCodeLength) |
| { |
| if (code.length < newCodeLength) |
| { |
| // Add 20% to avoid extending the arrays too often. |
| newCodeLength = newCodeLength * 6 / 5; |
| |
| byte[] newCode = new byte[newCodeLength]; |
| System.arraycopy(code, 0, newCode, 0, codeLength); |
| code = newCode; |
| |
| int[] newOldInstructionOffsets = new int[newCodeLength]; |
| System.arraycopy(oldInstructionOffsets, 0, newOldInstructionOffsets, 0, codeLength); |
| oldInstructionOffsets = newOldInstructionOffsets; |
| } |
| } |
| |
| |
| /** |
| * Adjusts the given jump offsets for the instruction at the given offset. |
| */ |
| private void remapJumpOffsets(int offset, int[] jumpOffsets) |
| { |
| for (int index = 0; index < jumpOffsets.length; index++) |
| { |
| jumpOffsets[index] = remapBranchOffset(offset, jumpOffsets[index]); |
| } |
| } |
| |
| |
| /** |
| * Computes the new branch offset for the instruction at the given new offset |
| * with the given old branch offset. |
| */ |
| private int remapBranchOffset(int newInstructionOffset, int branchOffset) |
| { |
| if (newInstructionOffset < 0 || |
| newInstructionOffset > codeLength) |
| { |
| throw new IllegalArgumentException("Invalid instruction offset ["+newInstructionOffset +"] in code with length ["+codeLength+"]"); |
| } |
| |
| int oldInstructionOffset = oldInstructionOffsets[newInstructionOffset]; |
| |
| return remapInstructionOffset(oldInstructionOffset + branchOffset) - |
| remapInstructionOffset(oldInstructionOffset); |
| } |
| |
| |
| /** |
| * Computes the new instruction offset for the instruction at the given old |
| * offset. |
| */ |
| private int remapInstructionOffset(int oldInstructionOffset) |
| { |
| if (oldInstructionOffset < 0 || |
| oldInstructionOffset > codeFragmentLengths[level]) |
| { |
| throw new IllegalArgumentException("Instruction offset ["+oldInstructionOffset +"] out of range in code fragment with length ["+codeFragmentLengths[level]+"] at level "+level); |
| } |
| |
| int newInstructionOffset = instructionOffsetMap[level][oldInstructionOffset]; |
| if (newInstructionOffset == INVALID) |
| { |
| throw new IllegalArgumentException("Invalid instruction offset ["+oldInstructionOffset +"] in code fragment at level "+level); |
| } |
| |
| return newInstructionOffset; |
| } |
| |
| |
| /** |
| * Returns whether the given old instruction offset can be remapped at the |
| */ |
| private boolean remappableInstructionOffset(int oldInstructionOffset) |
| { |
| return |
| oldInstructionOffset <= codeFragmentLengths[level] && |
| instructionOffsetMap[level][oldInstructionOffset] > INVALID; |
| } |
| |
| |
| /** |
| * Returns the given list of exceptions, without the ones that have empty |
| * code blocks. |
| */ |
| private int removeEmptyExceptions(ExceptionInfo[] exceptionInfos, |
| int exceptionInfoCount) |
| { |
| // Overwrite all empty exceptions. |
| int newIndex = 0; |
| for (int index = 0; index < exceptionInfoCount; index++) |
| { |
| ExceptionInfo exceptionInfo = exceptionInfos[index]; |
| if (exceptionInfo.u2startPC < exceptionInfo.u2endPC) |
| { |
| exceptionInfos[newIndex++] = exceptionInfo; |
| } |
| } |
| |
| // Clear the unused array entries. |
| for (int index = newIndex; index < exceptionInfoCount; index++) |
| { |
| exceptionInfos[index] = null; |
| } |
| |
| return newIndex; |
| } |
| |
| |
| /** |
| * Returns the given list of line numbers, without the ones that have empty |
| * code blocks or that exceed the code size. |
| */ |
| private int removeEmptyLineNumbers(LineNumberInfo[] lineNumberInfos, |
| int lineNumberInfoCount, |
| int codeLength) |
| { |
| // Overwrite all empty line number entries. |
| int newIndex = 0; |
| for (int index = 0; index < lineNumberInfoCount; index++) |
| { |
| LineNumberInfo lineNumberInfo = lineNumberInfos[index]; |
| int startPC = lineNumberInfo.u2startPC; |
| if (startPC < codeLength && |
| (index == 0 || startPC > lineNumberInfos[index-1].u2startPC)) |
| { |
| lineNumberInfos[newIndex++] = lineNumberInfo; |
| } |
| } |
| |
| // Clear the unused array entries. |
| for (int index = newIndex; index < lineNumberInfoCount; index++) |
| { |
| lineNumberInfos[index] = null; |
| } |
| |
| return newIndex; |
| } |
| |
| |
| /** |
| * Returns the given list of local variables, without the ones that have empty |
| * code blocks or that exceed the actual number of local variables. |
| */ |
| private int removeEmptyLocalVariables(LocalVariableInfo[] localVariableInfos, |
| int localVariableInfoCount, |
| int maxLocals) |
| { |
| // Overwrite all empty local variable entries. |
| int newIndex = 0; |
| for (int index = 0; index < localVariableInfoCount; index++) |
| { |
| LocalVariableInfo localVariableInfo = localVariableInfos[index]; |
| if (localVariableInfo.u2length > 0 && |
| localVariableInfo.u2index < maxLocals) |
| { |
| localVariableInfos[newIndex++] = localVariableInfo; |
| } |
| } |
| |
| // Clear the unused array entries. |
| for (int index = newIndex; index < localVariableInfoCount; index++) |
| { |
| localVariableInfos[index] = null; |
| } |
| |
| return newIndex; |
| } |
| |
| |
| /** |
| * Returns the given list of local variable types, without the ones that |
| * have empty code blocks or that exceed the actual number of local variables. |
| */ |
| private int removeEmptyLocalVariableTypes(LocalVariableTypeInfo[] localVariableTypeInfos, |
| int localVariableTypeInfoCount, |
| int maxLocals) |
| { |
| // Overwrite all empty local variable type entries. |
| int newIndex = 0; |
| for (int index = 0; index < localVariableTypeInfoCount; index++) |
| { |
| LocalVariableTypeInfo localVariableTypeInfo = localVariableTypeInfos[index]; |
| if (localVariableTypeInfo.u2length > 0 && |
| localVariableTypeInfo.u2index < maxLocals) |
| { |
| localVariableTypeInfos[newIndex++] = localVariableTypeInfo; |
| } |
| } |
| |
| // Clear the unused array entries. |
| for (int index = newIndex; index < localVariableTypeInfoCount; index++) |
| { |
| localVariableTypeInfos[index] = null; |
| } |
| |
| return newIndex; |
| } |
| |
| |
| private void println(String string1, String string2) |
| { |
| print(string1, string2); |
| |
| System.out.println(); |
| } |
| |
| private void print(String string1, String string2) |
| { |
| System.out.print(string1); |
| |
| for (int index = 0; index < level; index++) |
| { |
| System.out.print(" "); |
| } |
| |
| System.out.print(string2); |
| } |
| |
| |
| public static void main(String[] args) |
| { |
| CodeAttributeComposer composer = new CodeAttributeComposer(); |
| |
| composer.beginCodeFragment(4); |
| composer.appendInstruction(0, new SimpleInstruction(InstructionConstants.OP_ICONST_0)); |
| composer.appendInstruction(1, new VariableInstruction(InstructionConstants.OP_ISTORE, 0)); |
| composer.appendInstruction(2, new BranchInstruction(InstructionConstants.OP_GOTO, 1)); |
| |
| composer.beginCodeFragment(4); |
| composer.appendInstruction(0, new VariableInstruction(InstructionConstants.OP_IINC, 0, 1)); |
| composer.appendInstruction(1, new VariableInstruction(InstructionConstants.OP_ILOAD, 0)); |
| composer.appendInstruction(2, new SimpleInstruction(InstructionConstants.OP_ICONST_5)); |
| composer.appendInstruction(3, new BranchInstruction(InstructionConstants.OP_IFICMPLT, -3)); |
| composer.endCodeFragment(); |
| |
| composer.appendInstruction(3, new SimpleInstruction(InstructionConstants.OP_RETURN)); |
| composer.endCodeFragment(); |
| } |
| } |
