diff options
Diffstat (limited to 'src/proguard/optimize/evaluation/EvaluationShrinker.java')
| -rw-r--r-- | src/proguard/optimize/evaluation/EvaluationShrinker.java | 290 |
1 files changed, 230 insertions, 60 deletions
diff --git a/src/proguard/optimize/evaluation/EvaluationShrinker.java b/src/proguard/optimize/evaluation/EvaluationShrinker.java index 1463feb..bc5f658 100644 --- a/src/proguard/optimize/evaluation/EvaluationShrinker.java +++ b/src/proguard/optimize/evaluation/EvaluationShrinker.java @@ -2,7 +2,7 @@ * ProGuard -- shrinking, optimization, obfuscation, and preverification * of Java bytecode. * - * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) + * Copyright (c) 2002-2011 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 @@ -34,6 +34,8 @@ import proguard.evaluation.*; import proguard.evaluation.value.*; import proguard.optimize.info.*; +import java.util.Arrays; + /** * This AttributeVisitor simplifies the code attributes that it visits, based * on partial evaluation. @@ -55,13 +57,14 @@ implements AttributeVisitor private final InstructionVisitor extraDeletedInstructionVisitor; private final InstructionVisitor extraAddedInstructionVisitor; - private final PartialEvaluator partialEvaluator; - private final PartialEvaluator simplePartialEvaluator = new PartialEvaluator(); - private final SideEffectInstructionChecker sideEffectInstructionChecker = new SideEffectInstructionChecker(true); - private final MyUnusedParameterSimplifier unusedParameterSimplifier = new MyUnusedParameterSimplifier(); - private final MyProducerMarker producerMarker = new MyProducerMarker(); - private final MyStackConsistencyFixer stackConsistencyFixer = new MyStackConsistencyFixer(); - private final CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor(false); + private final PartialEvaluator partialEvaluator; + private final PartialEvaluator simplePartialEvaluator = new PartialEvaluator(); + private final SideEffectInstructionChecker sideEffectInstructionChecker = new SideEffectInstructionChecker(true); + private final MyUnusedParameterSimplifier unusedParameterSimplifier = new MyUnusedParameterSimplifier(); + private final MyProducerMarker producerMarker = new MyProducerMarker(); + private final MyVariableInitializationMarker variableInitializationMarker = new MyVariableInitializationMarker(); + private final MyStackConsistencyFixer stackConsistencyFixer = new MyStackConsistencyFixer(); + private final CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor(false); private boolean[][] variablesNecessaryAfter = new boolean[ClassConstants.TYPICAL_CODE_LENGTH][ClassConstants.TYPICAL_VARIABLES_SIZE]; private boolean[][] stacksNecessaryAfter = new boolean[ClassConstants.TYPICAL_CODE_LENGTH][ClassConstants.TYPICAL_STACK_SIZE]; @@ -276,18 +279,10 @@ implements AttributeVisitor if (partialEvaluator.isTraced(offset) && !isInstructionNecessary(offset)) { - // Is the corresponding variable necessary anywhere in the code, - // accoriding to a simple partial evaluation? - int variableIndex = partialEvaluator.initializedVariable(offset); - if (variableIndex >= 0 && - isVariableInitializationNecessary(clazz, - method, - codeAttribute, - offset, - variableIndex)) - { - markInstruction(offset); - } + Instruction instruction = InstructionFactory.create(codeAttribute.code, + offset); + + instruction.accept(clazz, method, codeAttribute, offset, variableInitializationMarker); } } if (DEBUG) System.out.println(); @@ -467,7 +462,9 @@ implements AttributeVisitor */ private class MyUnusedParameterSimplifier extends SimplifiedVisitor - implements InstructionVisitor, ConstantVisitor, MemberVisitor + implements InstructionVisitor, + ConstantVisitor, + MemberVisitor { private int invocationOffset; private ConstantInstruction invocationInstruction; @@ -657,6 +654,40 @@ implements AttributeVisitor /** + * This InstructionVisitor marks variable initializations that are + * necessary to appease the JVM. + */ + private class MyVariableInitializationMarker + extends SimplifiedVisitor + implements InstructionVisitor + { + // Implementations for InstructionVisitor. + + public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {} + + + public void visitVariableInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VariableInstruction variableInstruction) + { + if (!variableInstruction.isLoad()) + { + int variableIndex = variableInstruction.variableIndex; + + if (isVariableInitialization(offset, + variableIndex) && + isVariableInitializationNecessary(clazz, + method, + codeAttribute, + offset, + variableIndex)) + { + markInstruction(offset); + } + } + } + } + + + /** * This InstructionVisitor fixes instructions locally, popping any unused * produced stack entries after marked instructions, and popping produced * stack entries and pushing missing stack entries instead of unmarked @@ -687,12 +718,23 @@ implements AttributeVisitor int requiredPushCount = 0; for (int stackIndex = 0; stackIndex < popCount; stackIndex++) { - // Is the stack entry required by other consumers? - if (!isStackSimplifiedBefore(offset, top - stackIndex) && - !isAnyStackEntryNecessaryAfter(tracedStack.getTopProducerValue(stackIndex).instructionOffsetValue(), top - stackIndex)) + InstructionOffsetValue producerOffsets = + tracedStack.getTopProducerValue(stackIndex).instructionOffsetValue(); + + if (!isStackSimplifiedBefore(offset, top - stackIndex)) { - // Remember to push it. - requiredPushCount++; + // Is the stack entry pushed by any producer, + // because it is required by other consumers? + if (isAnyStackEntryNecessaryAfter(producerOffsets, top - stackIndex)) + { + // Make sure it is pushed after all producers. + markStackEntriesAfter(producerOffsets, top - stackIndex); + } + else + { + // Remember to push it. + requiredPushCount++; + } } } @@ -757,9 +799,16 @@ implements AttributeVisitor int expectedPopCount = 0; for (int stackIndex = 0; stackIndex < popCount; stackIndex++) { - // Is the stack entry required by other consumers? - if (isAnyStackEntryNecessaryAfter(tracedStack.getTopProducerValue(stackIndex).instructionOffsetValue(), top - stackIndex)) + InstructionOffsetValue producerOffsets = + tracedStack.getTopProducerValue(stackIndex).instructionOffsetValue(); + + // Is the stack entry pushed by any producer, + // because it is required by other consumers? + if (isAnyStackEntryNecessaryAfter(producerOffsets, top - stackIndex)) { + // Make sure it is pushed after all producers. + markStackEntriesAfter(producerOffsets, top - stackIndex); + // Remember to pop it. expectedPopCount++; } @@ -1052,6 +1101,7 @@ implements AttributeVisitor byte oldOpcode = instruction.opcode; byte newOpcode = 0; + byte addOpcode = 0; // Simplify the popping instruction if possible. switch (oldOpcode) @@ -1232,9 +1282,20 @@ implements AttributeVisitor stackEntryPresent1) { // Will both elements be present? - if (stackEntryPresent0 && - stackEntryPresent1) + if (!stackEntryPresent1) { + // Pop the original top element (later bottom element). + newOpcode = InstructionConstants.OP_POP; + } + else if (!stackEntryPresent0) + { + // Swap both elements and pop the top one. + newOpcode = InstructionConstants.OP_SWAP; + addOpcode = InstructionConstants.OP_POP; + } + else + { + // Just swap both elements. newOpcode = InstructionConstants.OP_SWAP; } } @@ -1242,6 +1303,7 @@ implements AttributeVisitor } } + // Is there a replacement opcode? if (newOpcode == 0) { // Delete the instruction. @@ -1270,6 +1332,21 @@ implements AttributeVisitor if (DEBUG) System.out.println(" Replacing instruction "+instruction.toString(dupOffset)+" by "+replacementInstruction.toString()); } + + // Is there an additional opcode? + if (addOpcode != 0) + { + // Add the instruction. + Instruction additionalInstruction = new SimpleInstruction(addOpcode); + codeAttributeEditor.insertAfterInstruction(dupOffset, additionalInstruction); + + if (extraAddedInstructionVisitor != null) + { + extraAddedInstructionVisitor.visitSimpleInstruction(null, null, null, dupOffset, null); + } + + if (DEBUG) System.out.println(" Adding instruction "+additionalInstruction.toString(dupOffset)); + } } @@ -1596,10 +1673,7 @@ implements AttributeVisitor { for (int offset = 0; offset < codeLength; offset++) { - for (int index = 0; index < maxLocals; index++) - { - variablesNecessaryAfter[offset][index] = false; - } + Arrays.fill(variablesNecessaryAfter[offset], 0, maxLocals, false); } } @@ -1612,10 +1686,7 @@ implements AttributeVisitor { for (int offset = 0; offset < codeLength; offset++) { - for (int index = 0; index < maxStack; index++) - { - stacksNecessaryAfter[offset][index] = false; - } + Arrays.fill(stacksNecessaryAfter[offset], 0, maxStack, false); } } @@ -1628,10 +1699,7 @@ implements AttributeVisitor { for (int offset = 0; offset < codeLength; offset++) { - for (int index = 0; index < maxStack; index++) - { - stacksSimplifiedBefore[offset][index] = false; - } + Arrays.fill(stacksSimplifiedBefore[offset], 0, maxStack, false); } } @@ -1641,10 +1709,7 @@ implements AttributeVisitor } else { - for (int index = 0; index < codeLength; index++) - { - instructionsNecessary[index] = false; - } + Arrays.fill(instructionsNecessary, 0, codeLength, false); } } @@ -1670,6 +1735,34 @@ implements AttributeVisitor /** + * Returns whether the specified variable is initialized at the specified + * offset. + */ + private boolean isVariableInitialization(int instructionOffset, + int variableIndex) + { + // Wasn't the variable set yet? + Value valueBefore = partialEvaluator.getVariablesBefore(instructionOffset).getValue(variableIndex); + if (valueBefore == null) + { + return true; + } + + // Is the computational type different now? + Value valueAfter = partialEvaluator.getVariablesAfter(instructionOffset).getValue(variableIndex); + if (valueAfter.computationalType() != valueBefore.computationalType()) + { + return true; + } + + // Was the producer an argument (which may be removed)? + Value producersBefore = partialEvaluator.getVariablesBefore(instructionOffset).getProducerValue(variableIndex); + return producersBefore.instructionOffsetValue().instructionOffsetCount() == 1 && + producersBefore.instructionOffsetValue().instructionOffset(0) == PartialEvaluator.AT_METHOD_ENTRY; + } + + + /** * Returns whether the specified variable must be initialized at the * specified offset, according to the verifier of the JVM. */ @@ -1686,8 +1779,8 @@ implements AttributeVisitor { if (DEBUG) System.out.println("Simple partial evaluation for initialization of variable v"+variableIndex+" at ["+initializationOffset+"]"); - // Lazily compute perform simple partial evaluation, the way the - // JVM preverifier would do it. + // Lazily perform simple partial evaluation, the way the JVM + // verifier would do it. simplePartialEvaluator.visitCodeAttribute(clazz, method, codeAttribute); if (DEBUG) System.out.println("End of simple partial evaluation for initialization of variable v"+variableIndex+" at ["+initializationOffset+"]"); @@ -1695,7 +1788,7 @@ implements AttributeVisitor // Check if the variable is necessary elsewhere. for (int offset = 0; offset < codeLength; offset++) { - if (isInstructionNecessary(offset)) + if (partialEvaluator.isTraced(offset)) { Value producer = partialEvaluator.getVariablesBefore(offset).getProducerValue(variableIndex); if (producer != null) @@ -1708,16 +1801,22 @@ implements AttributeVisitor InstructionOffsetValue simpleProducerOffsets = simpleProducer.instructionOffsetValue(); - // Does the sophisticated partial evaluation have fewer - // producers than the simple one? - // And does the simple partial evaluation point to an - // initialization of the variable? - if (producerOffsets.instructionOffsetCount() < - simpleProducerOffsets.instructionOffsetCount() && - isVariableNecessaryAfterAny(producerOffsets, variableIndex) && - simpleProducerOffsets.contains(initializationOffset)) + if (DEBUG) { - // Then the initialization is necessary. + System.out.println(" ["+offset+"] producers ["+producerOffsets+"], simple producers ["+simpleProducerOffsets+"]"); + } + + // Is the variable being used without all of its + // immediate simple producers being marked? + if (isVariableNecessaryAfterAny(producerOffsets, variableIndex) && + !isVariableNecessaryAfterAll(simpleProducerOffsets, variableIndex)) + { + if (DEBUG) + { + System.out.println(" => initialization of variable v"+variableIndex+" at ["+initializationOffset+"] necessary"); + } + + // Then the initialization may be necessary. return true; } } @@ -1726,6 +1825,11 @@ implements AttributeVisitor } } + if (DEBUG) + { + System.out.println(" => initialization of variable v"+variableIndex+" at ["+initializationOffset+"] not necessary"); + } + return false; } @@ -1749,7 +1853,7 @@ implements AttributeVisitor /** * Returns whether the specified variable is ever necessary after any - * instruction in the specified block. + * instructions in the specified block. */ private boolean isVariableNecessaryAfterAny(int startOffset, int endOffset, @@ -1769,7 +1873,7 @@ implements AttributeVisitor /** * Returns whether the specified variable is ever necessary after any - * instruction in the specified set of instructions offsets. + * instructions in the specified set of instructions offsets. */ private boolean isVariableNecessaryAfterAny(InstructionOffsetValue instructionOffsetValue, int variableIndex) @@ -1789,6 +1893,28 @@ implements AttributeVisitor } + /** + * Returns whether the specified variable is ever necessary after all + * instructions in the specified set of instructions offsets. + */ + private boolean isVariableNecessaryAfterAll(InstructionOffsetValue instructionOffsetValue, + int variableIndex) + { + int count = instructionOffsetValue.instructionOffsetCount(); + + for (int index = 0; index < count; index++) + { + if (!isVariableNecessaryAfter(instructionOffsetValue.instructionOffset(index), + variableIndex)) + { + return false; + } + } + + return true; + } + + private boolean isVariableNecessaryAfter(int instructionOffset, int variableIndex) { @@ -1797,6 +1923,36 @@ implements AttributeVisitor } + /** + * Marks the stack entries after the given offsets. + * @param instructionOffsets the offsets of the stack entries to be marked. + * @param stackIndex the index of the stack entries to be marked + * (counting from the bottom). + */ + private void markStackEntriesAfter(InstructionOffsetValue instructionOffsets, + int stackIndex) + { + if (instructionOffsets != null) + { + int offsetCount = instructionOffsets.instructionOffsetCount(); + for (int offsetIndex = 0; offsetIndex < offsetCount; offsetIndex++) + { + // Make sure the stack entry and the instruction are marked + // at the producing offset. + int offset = instructionOffsets.instructionOffset(offsetIndex); + + markStackEntryAfter(offset, stackIndex); + } + } + } + + + /** + * Marks the stack entry after the given offset. + * @param instructionOffset the offset of the stack entry to be marked. + * @param stackIndex the index of the stack entry to be marked + * (counting from the bottom). + */ private void markStackEntryAfter(int instructionOffset, int stackIndex) { @@ -1814,6 +1970,13 @@ implements AttributeVisitor } + /** + * Returns whether any of the stack entries after the given offsets are + * necessary. + * @param instructionOffsets the offsets of the stack entries to be checked. + * @param stackIndex the index of the stack entries to be checked + * (counting from the bottom). + */ private boolean isAnyStackEntryNecessaryAfter(InstructionOffsetValue instructionOffsets, int stackIndex) { @@ -1831,6 +1994,13 @@ implements AttributeVisitor } + /** + * Returns whether any of the stack entries after the given offset are + * necessary. + * @param instructionOffset the offset of the stack entry to be checked. + * @param stackIndex the index of the stack entry to be checked + * (counting from the bottom). + */ private boolean isStackEntryNecessaryAfter(int instructionOffset, int stackIndex) { |