diff options
Diffstat (limited to 'src/proguard/optimize/info/SideEffectInstructionChecker.java')
| -rw-r--r-- | src/proguard/optimize/info/SideEffectInstructionChecker.java | 239 |
1 files changed, 161 insertions, 78 deletions
diff --git a/src/proguard/optimize/info/SideEffectInstructionChecker.java b/src/proguard/optimize/info/SideEffectInstructionChecker.java index 8be9dc1..91f1f02 100644 --- a/src/proguard/optimize/info/SideEffectInstructionChecker.java +++ b/src/proguard/optimize/info/SideEffectInstructionChecker.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) 2002-2013 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 @@ -29,11 +29,14 @@ import proguard.classfile.instruction.visitor.InstructionVisitor; import proguard.classfile.util.SimplifiedVisitor; import proguard.classfile.visitor.*; +import java.util.*; + /** - * This class can tell whether an instruction has any side effects. Return - * instructions can be included or not. + * This class can tell whether an instruction has any side effects outside of + * its method. Return instructions can be included or not. * * @see ReadWriteFieldMarker + * @see StaticInitializerContainingClassMarker * @see NoSideEffectMethodMarker * @see SideEffectMethodMarker * @author Eric Lafortune @@ -44,23 +47,38 @@ implements InstructionVisitor, ConstantVisitor, MemberVisitor { + private static final boolean OPTIMIZE_CONSERVATIVELY = System.getProperty("optimize.conservatively") != null; + + private final boolean includeReturnInstructions; + private final boolean includeLocalFieldAccess; // A return value for the visitor methods. + private Clazz referencingClass; private boolean hasSideEffects; - public SideEffectInstructionChecker(boolean includeReturnInstructions) + public SideEffectInstructionChecker(boolean includeReturnInstructions, + boolean includeLocalFieldAccess) { this.includeReturnInstructions = includeReturnInstructions; + this.includeLocalFieldAccess = includeLocalFieldAccess; } - public boolean hasSideEffects(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) + /** + * Returns whether the given instruction has side effects outside of its + * method. + */ + public boolean hasSideEffects(Clazz clazz, + Method method, + CodeAttribute codeAttribute, + int offset, + Instruction instruction) { hasSideEffects = false; - instruction.accept(clazz, method, codeAttribute, offset, this); + instruction.accept(clazz, method, codeAttribute, offset, this); return hasSideEffects; } @@ -76,29 +94,46 @@ implements InstructionVisitor, byte opcode = simpleInstruction.opcode; // Check for instructions that might cause side effects. - if (opcode == InstructionConstants.OP_IASTORE || - opcode == InstructionConstants.OP_LASTORE || - opcode == InstructionConstants.OP_FASTORE || - opcode == InstructionConstants.OP_DASTORE || - opcode == InstructionConstants.OP_AASTORE || - opcode == InstructionConstants.OP_BASTORE || - opcode == InstructionConstants.OP_CASTORE || - opcode == InstructionConstants.OP_SASTORE || - opcode == InstructionConstants.OP_ATHROW || - opcode == InstructionConstants.OP_MONITORENTER || - opcode == InstructionConstants.OP_MONITOREXIT || - (includeReturnInstructions && - (opcode == InstructionConstants.OP_IRETURN || - opcode == InstructionConstants.OP_LRETURN || - opcode == InstructionConstants.OP_FRETURN || - opcode == InstructionConstants.OP_DRETURN || - opcode == InstructionConstants.OP_ARETURN || - opcode == InstructionConstants.OP_RETURN))) + switch (opcode) { - // These instructions always cause a side effect. - hasSideEffects = true; + case InstructionConstants.OP_IALOAD: + case InstructionConstants.OP_LALOAD: + case InstructionConstants.OP_FALOAD: + case InstructionConstants.OP_DALOAD: + case InstructionConstants.OP_AALOAD: + case InstructionConstants.OP_BALOAD: + case InstructionConstants.OP_CALOAD: + case InstructionConstants.OP_SALOAD: + // These instructions strictly taken may cause a side effect + // (NullPointerException, ArrayIndexOutOfBoundsException). + hasSideEffects = OPTIMIZE_CONSERVATIVELY; + break; + + case InstructionConstants.OP_IASTORE: + case InstructionConstants.OP_LASTORE: + case InstructionConstants.OP_FASTORE: + case InstructionConstants.OP_DASTORE: + case InstructionConstants.OP_AASTORE: + case InstructionConstants.OP_BASTORE: + case InstructionConstants.OP_CASTORE: + case InstructionConstants.OP_SASTORE: + case InstructionConstants.OP_ATHROW : + case InstructionConstants.OP_MONITORENTER: + case InstructionConstants.OP_MONITOREXIT: + // These instructions always cause a side effect. + hasSideEffects = true; + break; + + case InstructionConstants.OP_IRETURN: + case InstructionConstants.OP_LRETURN: + case InstructionConstants.OP_FRETURN: + case InstructionConstants.OP_DRETURN: + case InstructionConstants.OP_ARETURN: + case InstructionConstants.OP_RETURN: + // These instructions may have a side effect. + hasSideEffects = includeReturnInstructions; + break; } - } @@ -107,10 +142,12 @@ implements InstructionVisitor, byte opcode = variableInstruction.opcode; // Check for instructions that might cause side effects. - if (includeReturnInstructions && - opcode == InstructionConstants.OP_RET) + switch (opcode) { - hasSideEffects = true; + case InstructionConstants.OP_RET: + // This instruction may have a side effect. + hasSideEffects = includeReturnInstructions; + break; } } @@ -120,16 +157,41 @@ implements InstructionVisitor, byte opcode = constantInstruction.opcode; // Check for instructions that might cause side effects. - if (opcode == InstructionConstants.OP_PUTSTATIC || - opcode == InstructionConstants.OP_PUTFIELD || - opcode == InstructionConstants.OP_INVOKEVIRTUAL || - opcode == InstructionConstants.OP_INVOKESPECIAL || - opcode == InstructionConstants.OP_INVOKESTATIC || - opcode == InstructionConstants.OP_INVOKEINTERFACE) + switch (opcode) { - // Check if the field is write-only or volatile, or if the invoked - // method is causing any side effects. - clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); + case InstructionConstants.OP_GETSTATIC: + case InstructionConstants.OP_PUTSTATIC: + case InstructionConstants.OP_INVOKESPECIAL: + case InstructionConstants.OP_INVOKESTATIC: + // Check if the field is write-only or volatile, or if the + // invoked method is causing any side effects. + clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); + break; + + case InstructionConstants.OP_GETFIELD: + case InstructionConstants.OP_PUTFIELD: + case InstructionConstants.OP_INVOKEVIRTUAL: + case InstructionConstants.OP_INVOKEINTERFACE: + case InstructionConstants.OP_INVOKEDYNAMIC: + if (OPTIMIZE_CONSERVATIVELY) + { + // These instructions strictly taken may cause a side effect + // (NullPointerException). + hasSideEffects = true; + } + else + { + // Check if the field is write-only or volatile, or if the + // invoked method is causing any side effects. + clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this); + } + break; + + case InstructionConstants.OP_CHECKCAST: + // This instructions strictly taken may cause a side effect + // (ClassCastException). + hasSideEffects = OPTIMIZE_CONSERVATIVELY; + break; } } @@ -139,59 +201,48 @@ implements InstructionVisitor, byte opcode = branchInstruction.opcode; // Check for instructions that might cause side effects. - if (includeReturnInstructions && - (opcode == InstructionConstants.OP_JSR || - opcode == InstructionConstants.OP_JSR_W)) + switch (opcode) { - hasSideEffects = true; + case InstructionConstants.OP_JSR: + case InstructionConstants.OP_JSR_W: + hasSideEffects = includeReturnInstructions; + break; } } // Implementations for ConstantVisitor. + public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant) + { + // We'll have to assume invoking an unknown method has side effects. + hasSideEffects = true; + } + + public void visitFieldrefConstant(Clazz clazz, FieldrefConstant fieldrefConstant) { + // Pass the referencing class. + referencingClass = clazz; + // We'll have to assume accessing an unknown field has side effects. hasSideEffects = true; - // Check the referenced field. + // Check the referenced field, if known. fieldrefConstant.referencedMemberAccept(this); } public void visitAnyMethodrefConstant(Clazz clazz, RefConstant refConstant) { - Member referencedMember = refConstant.referencedMember; + // Pass the referencing class. + referencingClass = clazz; - // Do we have a reference to the method? - if (referencedMember == null) - { - // We'll have to assume invoking the unknown method has side effects. - hasSideEffects = true; - } - else - { - // First check the referenced method itself. - refConstant.referencedMemberAccept(this); - - // If the result isn't conclusive, check down the hierarchy. - if (!hasSideEffects) - { - Clazz referencedClass = refConstant.referencedClass; - Method referencedMethod = (Method)referencedMember; - - // Check all other implementations of the method down the class - // hierarchy. - if ((referencedMethod.getAccessFlags() & ClassConstants.INTERNAL_ACC_PRIVATE) == 0) - { - clazz.hierarchyAccept(false, false, false, true, - new NamedMethodVisitor(referencedMethod.getName(referencedClass), - referencedMethod.getDescriptor(referencedClass), - this)); - } - } - } + // We'll have to assume invoking an unknown method has side effects. + hasSideEffects = true; + + // Check the referenced method, if known. + refConstant.referencedMemberAccept(this); } @@ -199,14 +250,25 @@ implements InstructionVisitor, public void visitProgramField(ProgramClass programClass, ProgramField programField) { - hasSideEffects = ReadWriteFieldMarker.isRead(programField); + hasSideEffects = + (includeLocalFieldAccess || !programClass.equals(referencingClass)) && + ((ReadWriteFieldMarker.isRead(programField) && + ReadWriteFieldMarker.isWritten(programField)) || + ((programField.getAccessFlags() & ClassConstants.INTERNAL_ACC_VOLATILE) != 0) || + (!programClass.equals(referencingClass) && + !initializedSuperClasses(referencingClass).containsAll(initializedSuperClasses(programClass)))); } public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) { - hasSideEffects = hasSideEffects || - SideEffectMethodMarker.hasSideEffects(programMethod); + // Note that side effects already include synchronization of some + // implementation of the method. + hasSideEffects = + !NoSideEffectMethodMarker.hasNoSideEffects(programMethod) && + (SideEffectMethodMarker.hasSideEffects(programMethod) || + (!programClass.equals(referencingClass) && + !initializedSuperClasses(referencingClass).containsAll(initializedSuperClasses(programClass)))); } @@ -218,7 +280,28 @@ implements InstructionVisitor, public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) { - hasSideEffects = hasSideEffects || - !NoSideEffectMethodMarker.hasNoSideEffects(libraryMethod); + hasSideEffects = + !NoSideEffectMethodMarker.hasNoSideEffects(libraryMethod); + } + + + /** + * Returns the set of superclasses and interfaces that are initialized. + */ + private Set initializedSuperClasses(Clazz clazz) + { + Set set = new HashSet(); + + // Visit all superclasses and interfaces, collecting the ones that have + // static initializers. + clazz.hierarchyAccept(true, true, true, false, + new StaticInitializerContainingClassFilter( + new NamedMethodVisitor(ClassConstants.INTERNAL_METHOD_NAME_CLINIT, + ClassConstants.INTERNAL_METHOD_TYPE_CLINIT, + new SideEffectMethodFilter( + new MemberToClassVisitor( + new ClassCollector(set)))))); + + return set; } } |