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Diffstat (limited to 'src/proguard/optimize/TailRecursionSimplifier.java')
| -rw-r--r-- | src/proguard/optimize/TailRecursionSimplifier.java | 355 |
1 files changed, 0 insertions, 355 deletions
diff --git a/src/proguard/optimize/TailRecursionSimplifier.java b/src/proguard/optimize/TailRecursionSimplifier.java deleted file mode 100644 index dd38d6b..0000000 --- a/src/proguard/optimize/TailRecursionSimplifier.java +++ /dev/null @@ -1,355 +0,0 @@ -/* - * ProGuard -- shrinking, optimization, obfuscation, and preverification - * of Java bytecode. - * - * Copyright (c) 2002-2014 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.optimize; - -import proguard.classfile.*; -import proguard.classfile.attribute.*; -import proguard.classfile.attribute.visitor.*; -import proguard.classfile.constant.*; -import proguard.classfile.constant.visitor.ConstantVisitor; -import proguard.classfile.editor.CodeAttributeComposer; -import proguard.classfile.instruction.*; -import proguard.classfile.instruction.visitor.InstructionVisitor; -import proguard.classfile.util.*; - -/** - * This MemberVisitor simplifies tail recursion calls in all methods that it - * visits. - * - * @author Eric Lafortune - */ -public class TailRecursionSimplifier -extends SimplifiedVisitor -implements AttributeVisitor, - InstructionVisitor, - ConstantVisitor, - ExceptionInfoVisitor -{ - //* - private static final boolean DEBUG = false; - /*/ - private static boolean DEBUG = true; - //*/ - - - private final InstructionVisitor extraTailRecursionVisitor; - - - private final CodeAttributeComposer codeAttributeComposer = new CodeAttributeComposer(); - private final MyRecursionChecker recursionChecker = new MyRecursionChecker(); - - private Method targetMethod; - private boolean inlinedAny; - - - - /** - * Creates a new TailRecursionSimplifier. - */ - public TailRecursionSimplifier() - { - this(null); - } - - - /** - * Creates a new TailRecursionSimplifier with an extra visitor. - * @param extraTailRecursionVisitor an optional extra visitor for all - * simplified tail recursions. - */ - public TailRecursionSimplifier(InstructionVisitor extraTailRecursionVisitor) - { - this.extraTailRecursionVisitor = extraTailRecursionVisitor; - } - - - // Implementations for AttributeVisitor. - - public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} - - - public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) - { - int accessFlags = method.getAccessFlags(); - - if (// Only check the method if it is private, static, or final. - (accessFlags & (ClassConstants.ACC_PRIVATE | - ClassConstants.ACC_STATIC | - ClassConstants.ACC_FINAL)) != 0 && - - // Only check the method if it is not synchronized, etc. - (accessFlags & (ClassConstants.ACC_SYNCHRONIZED | - ClassConstants.ACC_NATIVE | - ClassConstants.ACC_ABSTRACT)) == 0) - { -// codeAttributeComposer.DEBUG = DEBUG = -// clazz.getName().equals("abc/Def") && -// method.getName(clazz).equals("abc"); - - targetMethod = method; - inlinedAny = false; - codeAttributeComposer.reset(); - - // The code may expand, due to expanding constant and variable - // instructions. - codeAttributeComposer.beginCodeFragment(codeAttribute.u4codeLength); - - // Copy the instructions. - codeAttribute.instructionsAccept(clazz, method, this); - - // Update the code attribute if any code has been inlined. - if (inlinedAny) - { - // Copy the exceptions. - codeAttribute.exceptionsAccept(clazz, method, this); - - // Append a label just after the code. - codeAttributeComposer.appendLabel(codeAttribute.u4codeLength); - - codeAttributeComposer.endCodeFragment(); - - codeAttributeComposer.visitCodeAttribute(clazz, method, codeAttribute); - } - } - } - - - // Implementations for InstructionVisitor. - - public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) - { - // Copy the instruction. - codeAttributeComposer.appendInstruction(offset, instruction); - } - - - public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction) - { - // Is it a method invocation? - switch (constantInstruction.opcode) - { - case InstructionConstants.OP_INVOKEVIRTUAL: - case InstructionConstants.OP_INVOKESPECIAL: - case InstructionConstants.OP_INVOKESTATIC: - { - // Is it a recursive call? - clazz.constantPoolEntryAccept(constantInstruction.constantIndex, recursionChecker); - - if (recursionChecker.isRecursive()) - { - // Is the next instruction a return? - int nextOffset = - offset + constantInstruction.length(offset); - - Instruction nextInstruction = - InstructionFactory.create(codeAttribute.code, nextOffset); - - switch (nextInstruction.opcode) - { - case InstructionConstants.OP_IRETURN: - case InstructionConstants.OP_LRETURN: - case InstructionConstants.OP_FRETURN: - case InstructionConstants.OP_DRETURN: - case InstructionConstants.OP_ARETURN: - case InstructionConstants.OP_RETURN: - { - // Isn't the recursive call inside a try/catch block? - codeAttribute.exceptionsAccept(clazz, method, offset, recursionChecker); - - if (recursionChecker.isRecursive()) - { - if (DEBUG) - { - System.out.println("TailRecursionSimplifier: ["+ - clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz)+"], inlining "+constantInstruction.toString(offset)); - } - - // Append a label. - codeAttributeComposer.appendLabel(offset); - - storeParameters(clazz, method); - - // Branch back to the start of the method. - int gotoOffset = offset + 1; - codeAttributeComposer.appendInstruction(gotoOffset, - new BranchInstruction(InstructionConstants.OP_GOTO, -gotoOffset)); - - // The original return instruction will be - // removed elsewhere, if possible. - - // Remember that the code has changed. - inlinedAny = true; - - if (extraTailRecursionVisitor != null) - { - extraTailRecursionVisitor.visitConstantInstruction(clazz, method, codeAttribute, offset, constantInstruction); - } - - // The invocation itself is no longer necessary. - return; - } - } - } - } - - break; - } - } - - // Copy the instruction. - codeAttributeComposer.appendInstruction(offset, constantInstruction); - } - - - // Implementations for ExceptionInfoVisitor. - - public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo) - { - codeAttributeComposer.appendException(new ExceptionInfo(exceptionInfo.u2startPC, - exceptionInfo.u2endPC, - exceptionInfo.u2handlerPC, - exceptionInfo.u2catchType)); - } - - - /** - * This ConstantVisitor and ExceptionInfoVisitor returns whether a method - * invocation can be treated as tail-recursive. - */ - private class MyRecursionChecker - extends SimplifiedVisitor - implements ConstantVisitor, - ExceptionInfoVisitor - { - private boolean recursive; - - - /** - * Returns whether the method invocation can be treated as - * tail-recursive. - */ - public boolean isRecursive() - { - return recursive; - } - - // Implementations for ConstantVisitor. - - public void visitAnyMethodrefConstant(Clazz clazz, RefConstant methodrefConstant) - { - recursive = targetMethod.equals(methodrefConstant.referencedMember); - } - - - // Implementations for ExceptionInfoVisitor. - - public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo) - { - recursive = false; - } - } - - - // Small utility methods. - - /** - * Appends instructions to pop the parameters for the given method, storing - * them in new local variables. - */ - private void storeParameters(Clazz clazz, Method method) - { - String descriptor = method.getDescriptor(clazz); - - boolean isStatic = - (method.getAccessFlags() & ClassConstants.ACC_STATIC) != 0; - - // Count the number of parameters, taking into account their categories. - int parameterSize = ClassUtil.internalMethodParameterSize(descriptor); - int parameterOffset = isStatic ? 0 : 1; - - // Store the parameter types. - String[] parameterTypes = new String[parameterSize]; - - InternalTypeEnumeration internalTypeEnumeration = - new InternalTypeEnumeration(descriptor); - - for (int parameterIndex = 0; parameterIndex < parameterSize; parameterIndex++) - { - String parameterType = internalTypeEnumeration.nextType(); - parameterTypes[parameterIndex] = parameterType; - if (ClassUtil.internalTypeSize(parameterType) == 2) - { - parameterIndex++; - } - } - - codeAttributeComposer.beginCodeFragment(parameterSize + 1); - - // Go over the parameter types backward, storing the stack entries - // in their corresponding variables. - for (int parameterIndex = parameterSize-1; parameterIndex >= 0; parameterIndex--) - { - String parameterType = parameterTypes[parameterIndex]; - if (parameterType != null) - { - byte opcode; - switch (parameterType.charAt(0)) - { - case ClassConstants.TYPE_BOOLEAN: - case ClassConstants.TYPE_BYTE: - case ClassConstants.TYPE_CHAR: - case ClassConstants.TYPE_SHORT: - case ClassConstants.TYPE_INT: - opcode = InstructionConstants.OP_ISTORE; - break; - - case ClassConstants.TYPE_LONG: - opcode = InstructionConstants.OP_LSTORE; - break; - - case ClassConstants.TYPE_FLOAT: - opcode = InstructionConstants.OP_FSTORE; - break; - - case ClassConstants.TYPE_DOUBLE: - opcode = InstructionConstants.OP_DSTORE; - break; - - default: - opcode = InstructionConstants.OP_ASTORE; - break; - } - - codeAttributeComposer.appendInstruction(parameterSize-parameterIndex-1, - new VariableInstruction(opcode, parameterOffset + parameterIndex)); - } - } - - // Put the 'this' reference in variable 0. - if (!isStatic) - { - codeAttributeComposer.appendInstruction(parameterSize, - new VariableInstruction(InstructionConstants.OP_ASTORE, 0)); - } - - codeAttributeComposer.endCodeFragment(); - } -}
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