Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation * Stephan Herrmann <stephan@cs.tu-berlin.de> - Contributions for * bug 292478 - Report potentially null across variable assignment, * bug 185682 - Increment/decrement operators mark local variables as read * bug 331649 - [compiler][null] consider null annotations for fields * bug 383368 - [compiler][null] syntactic null analysis for field references * Bug 412203 - [compiler] Internal compiler error: java.lang.IllegalArgumentException: info cannot be null * Bug 458396 - NPE in CodeStream.invoke() * Bug 407414 - [compiler][null] Incorrect warning on a primitive type being null * Jesper S Moller - <jesper@selskabet.org> - Contributions for * bug 382721 - [1.8][compiler] Effectively final variables needs special treatment * bug 378674 - "The method can be declared as static" is wrong * bug 404657 - [1.8][compiler] Analysis for effectively final variables fails to consider loops * bug 527554 - [18.3] Compiler support for JEP 286 Local-Variable Type *******************************************************************************/ package org.eclipse.jdt.internal.compiler.ast; import org.eclipse.jdt.core.compiler.CharOperation; import org.eclipse.jdt.internal.compiler.ASTVisitor; import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants; import org.eclipse.jdt.internal.compiler.codegen.CodeStream; import org.eclipse.jdt.internal.compiler.codegen.Opcodes; import org.eclipse.jdt.internal.compiler.flow.FlowContext; import org.eclipse.jdt.internal.compiler.flow.FlowInfo; import org.eclipse.jdt.internal.compiler.impl.CompilerOptions; import org.eclipse.jdt.internal.compiler.impl.Constant; import org.eclipse.jdt.internal.compiler.lookup.Binding; import org.eclipse.jdt.internal.compiler.lookup.BlockScope; import org.eclipse.jdt.internal.compiler.lookup.ClassScope; import org.eclipse.jdt.internal.compiler.lookup.FieldBinding; import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding; import org.eclipse.jdt.internal.compiler.lookup.MethodBinding; import org.eclipse.jdt.internal.compiler.lookup.MethodScope; import org.eclipse.jdt.internal.compiler.lookup.MissingTypeBinding; import org.eclipse.jdt.internal.compiler.lookup.ProblemFieldBinding; import org.eclipse.jdt.internal.compiler.lookup.ProblemReasons; import org.eclipse.jdt.internal.compiler.lookup.ProblemReferenceBinding; import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding; import org.eclipse.jdt.internal.compiler.lookup.Scope; import org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding; import org.eclipse.jdt.internal.compiler.lookup.TagBits; import org.eclipse.jdt.internal.compiler.lookup.TypeBinding; import org.eclipse.jdt.internal.compiler.lookup.TypeIds; import org.eclipse.jdt.internal.compiler.lookup.VariableBinding; import org.eclipse.jdt.internal.compiler.problem.AbortMethod; import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities; public class SingleNameReference extends NameReference implements OperatorIds { public static final int READ = 0; public static final int WRITE = 1; public char[] token; public MethodBinding[] syntheticAccessors; // [0]=read accessor [1]=write accessor public TypeBinding genericCast; public boolean isLabel;// flagging for break expression when expression is SwitchExpression - java 12 preview-feature public SingleNameReference(char[] source, long pos) { super(); this.token = source; this.sourceStart = (int) (pos >>> 32); this.sourceEnd = (int) pos; } @Override public FlowInfo analyseAssignment(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, Assignment assignment, boolean isCompound) { boolean isReachable = (flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0; // compound assignment extra work if (isCompound) { // check the variable part is initialized if blank final switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // reading a field FieldBinding fieldBinding = (FieldBinding) this.binding; if (fieldBinding.isBlankFinal() && currentScope.needBlankFinalFieldInitializationCheck(fieldBinding)) { FlowInfo fieldInits = flowContext.getInitsForFinalBlankInitializationCheck( fieldBinding.declaringClass.original(), flowInfo); if (!fieldInits.isDefinitelyAssigned(fieldBinding)) { currentScope.problemReporter().uninitializedBlankFinalField(fieldBinding, this); } } manageSyntheticAccessIfNecessary(currentScope, flowInfo, true /*read-access*/); break; case Binding.LOCAL: // reading a local variable // check if assigning a final blank field LocalVariableBinding localBinding; if (!flowInfo.isDefinitelyAssigned(localBinding = (LocalVariableBinding) this.binding)) { currentScope.problemReporter().uninitializedLocalVariable(localBinding, this, currentScope); // we could improve error msg here telling "cannot use compound assignment on final local variable" } if (localBinding.useFlag != LocalVariableBinding.USED) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=185682 // access from compound assignment does not prevent "unused" warning, unless unboxing is involved: if (isReachable && (this.implicitConversion & TypeIds.UNBOXING) != 0) { localBinding.useFlag = LocalVariableBinding.USED; } else { // use values < 0 to count the number of compound uses: if (localBinding.useFlag <= LocalVariableBinding.UNUSED) localBinding.useFlag--; } } } } if (assignment.expression != null) { flowInfo = assignment.expression.analyseCode(currentScope, flowContext, flowInfo).unconditionalInits(); } switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // assigning to a field manageSyntheticAccessIfNecessary(currentScope, flowInfo, false /*write-access*/); // check if assigning a final field FieldBinding fieldBinding = (FieldBinding) this.binding; if (fieldBinding.isFinal()) { // inside a context where allowed if (!isCompound && fieldBinding.isBlankFinal() && currentScope.allowBlankFinalFieldAssignment(fieldBinding)) { if (flowInfo.isPotentiallyAssigned(fieldBinding)) { currentScope.problemReporter().duplicateInitializationOfBlankFinalField(fieldBinding, this); } else { flowContext.recordSettingFinal(fieldBinding, this, flowInfo); } flowInfo.markAsDefinitelyAssigned(fieldBinding); } else { currentScope.problemReporter().cannotAssignToFinalField(fieldBinding, this); } } else if (!isCompound && (fieldBinding.isNonNull() || fieldBinding.type.isTypeVariable()) && TypeBinding.equalsEquals(fieldBinding.declaringClass, currentScope.enclosingReceiverType())) { // inherited fields are not tracked here // record assignment for detecting uninitialized non-null fields: flowInfo.markAsDefinitelyAssigned(fieldBinding); } break; case Binding.LOCAL: // assigning to a local variable LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; final boolean isFinal = localBinding.isFinal(); if (!flowInfo.isDefinitelyAssigned(localBinding)) {// for local variable debug attributes this.bits |= ASTNode.FirstAssignmentToLocal; } else { this.bits &= ~ASTNode.FirstAssignmentToLocal; } if (flowInfo.isPotentiallyAssigned(localBinding) || (this.bits & ASTNode.IsCapturedOuterLocal) != 0) { localBinding.tagBits &= ~TagBits.IsEffectivelyFinal; if (!isFinal && (this.bits & ASTNode.IsCapturedOuterLocal) != 0) { currentScope.problemReporter().cannotReferToNonEffectivelyFinalOuterLocal(localBinding, this); } } if (!isFinal && (localBinding.tagBits & TagBits.IsEffectivelyFinal) != 0 && (localBinding.tagBits & TagBits.IsArgument) == 0) { flowContext.recordSettingFinal(localBinding, this, flowInfo); } else if (isFinal) { if ((this.bits & ASTNode.DepthMASK) == 0) { // tolerate assignment to final local in unreachable code (45674) if ((isReachable && isCompound) || !localBinding.isBlankFinal()) { currentScope.problemReporter().cannotAssignToFinalLocal(localBinding, this); } else if (flowInfo.isPotentiallyAssigned(localBinding)) { currentScope.problemReporter().duplicateInitializationOfFinalLocal(localBinding, this); } else if ((this.bits & ASTNode.IsCapturedOuterLocal) != 0) { currentScope.problemReporter().cannotAssignToFinalOuterLocal(localBinding, this); } else { flowContext.recordSettingFinal(localBinding, this, flowInfo); } } else { currentScope.problemReporter().cannotAssignToFinalOuterLocal(localBinding, this); } } else /* avoid double diagnostic */ if ((localBinding.tagBits & TagBits.IsArgument) != 0) { currentScope.problemReporter().parameterAssignment(localBinding, this); } flowInfo.markAsDefinitelyAssigned(localBinding); } manageEnclosingInstanceAccessIfNecessary(currentScope, flowInfo); return flowInfo; } @Override public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) { return analyseCode(currentScope, flowContext, flowInfo, true); } @Override public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, boolean valueRequired) { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // reading a field if (valueRequired || currentScope.compilerOptions().complianceLevel >= ClassFileConstants.JDK1_4) { manageSyntheticAccessIfNecessary(currentScope, flowInfo, true /*read-access*/); } // check if reading a final blank field FieldBinding fieldBinding = (FieldBinding) this.binding; if (fieldBinding.isBlankFinal() && currentScope.needBlankFinalFieldInitializationCheck(fieldBinding)) { FlowInfo fieldInits = flowContext .getInitsForFinalBlankInitializationCheck(fieldBinding.declaringClass.original(), flowInfo); if (!fieldInits.isDefinitelyAssigned(fieldBinding)) { currentScope.problemReporter().uninitializedBlankFinalField(fieldBinding, this); } } break; case Binding.LOCAL: // reading a local variable LocalVariableBinding localBinding; if (!flowInfo.isDefinitelyAssigned(localBinding = (LocalVariableBinding) this.binding)) { currentScope.problemReporter().uninitializedLocalVariable(localBinding, this, currentScope); } if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0) { localBinding.useFlag = LocalVariableBinding.USED; } else if (localBinding.useFlag == LocalVariableBinding.UNUSED) { localBinding.useFlag = LocalVariableBinding.FAKE_USED; } } if (valueRequired) { manageEnclosingInstanceAccessIfNecessary(currentScope, flowInfo); } return flowInfo; } public TypeBinding checkFieldAccess(BlockScope scope) { FieldBinding fieldBinding = (FieldBinding) this.binding; this.constant = fieldBinding.constant(scope); this.bits &= ~ASTNode.RestrictiveFlagMASK; // clear bits this.bits |= Binding.FIELD; MethodScope methodScope = scope.methodScope(); if (fieldBinding.isStatic()) { // check if accessing enum static field in initializer ReferenceBinding declaringClass = fieldBinding.declaringClass; if (declaringClass.isEnum() && !scope.isModuleScope()) { SourceTypeBinding sourceType = scope.enclosingSourceType(); if (this.constant == Constant.NotAConstant && !methodScope.isStatic && (TypeBinding.equalsEquals(sourceType, declaringClass) || TypeBinding.equalsEquals(sourceType.superclass, declaringClass)) // enum constant body && methodScope.isInsideInitializerOrConstructor()) { scope.problemReporter().enumStaticFieldUsedDuringInitialization(fieldBinding, this); } } } else { if (scope.compilerOptions() .getSeverity(CompilerOptions.UnqualifiedFieldAccess) != ProblemSeverities.Ignore) { scope.problemReporter().unqualifiedFieldAccess(this, fieldBinding); } // must check for the static status.... if (methodScope.isStatic) { scope.problemReporter().staticFieldAccessToNonStaticVariable(this, fieldBinding); return fieldBinding.type; } else { scope.tagAsAccessingEnclosingInstanceStateOf(fieldBinding.declaringClass, false /* type variable access */); } } if (isFieldUseDeprecated(fieldBinding, scope, this.bits)) scope.problemReporter().deprecatedField(fieldBinding, this); if ((this.bits & ASTNode.IsStrictlyAssigned) == 0 && TypeBinding.equalsEquals(methodScope.enclosingSourceType(), fieldBinding.original().declaringClass) && methodScope.lastVisibleFieldID >= 0 && fieldBinding.id >= methodScope.lastVisibleFieldID && (!fieldBinding.isStatic() || methodScope.isStatic)) { scope.problemReporter().forwardReference(this, 0, fieldBinding); this.bits |= ASTNode.IgnoreNoEffectAssignCheck; } return fieldBinding.type; } @Override public boolean checkNPE(BlockScope scope, FlowContext flowContext, FlowInfo flowInfo, int ttlForFieldCheck) { if (!super.checkNPE(scope, flowContext, flowInfo, ttlForFieldCheck)) { CompilerOptions compilerOptions = scope.compilerOptions(); if (compilerOptions.isAnnotationBasedNullAnalysisEnabled) { if (this.binding instanceof FieldBinding) { return checkNullableFieldDereference(scope, (FieldBinding) this.binding, ((long) this.sourceStart << 32) + this.sourceEnd, flowContext, ttlForFieldCheck); } } } return false; } /** * @see org.eclipse.jdt.internal.compiler.ast.Expression#computeConversion(org.eclipse.jdt.internal.compiler.lookup.Scope, org.eclipse.jdt.internal.compiler.lookup.TypeBinding, org.eclipse.jdt.internal.compiler.lookup.TypeBinding) */ @Override public void computeConversion(Scope scope, TypeBinding runtimeTimeType, TypeBinding compileTimeType) { if (runtimeTimeType == null || compileTimeType == null) return; if (this.binding != null && this.binding.isValidBinding()) { TypeBinding originalType = null; if ((this.bits & Binding.FIELD) != 0) { // set the generic cast after the fact, once the type expectation is fully known (no need for strict cast) FieldBinding field = (FieldBinding) this.binding; FieldBinding originalBinding = field.original(); originalType = originalBinding.type; } else if ((this.bits & Binding.LOCAL) != 0) { LocalVariableBinding local = (LocalVariableBinding) this.binding; originalType = local.type; } // extra cast needed if field/local type is type variable if (originalType != null && originalType.leafComponentType().isTypeVariable()) { TypeBinding targetType = (!compileTimeType.isBaseType() && runtimeTimeType.isBaseType()) ? compileTimeType // unboxing: checkcast before conversion : runtimeTimeType; this.genericCast = originalType.genericCast(scope.boxing(targetType)); if (this.genericCast instanceof ReferenceBinding) { ReferenceBinding referenceCast = (ReferenceBinding) this.genericCast; if (!referenceCast.canBeSeenBy(scope)) { scope.problemReporter().invalidType(this, new ProblemReferenceBinding( CharOperation.splitOn('.', referenceCast.shortReadableName()), referenceCast, ProblemReasons.NotVisible)); } } } } super.computeConversion(scope, runtimeTimeType, compileTimeType); } @Override public void generateAssignment(BlockScope currentScope, CodeStream codeStream, Assignment assignment, boolean valueRequired) { // optimizing assignment like: i = i + 1 or i = 1 + i if (assignment.expression.isCompactableOperation()) { BinaryExpression operation = (BinaryExpression) assignment.expression; int operator = (operation.bits & ASTNode.OperatorMASK) >> ASTNode.OperatorSHIFT; SingleNameReference variableReference; if ((operation.left instanceof SingleNameReference) && ((variableReference = (SingleNameReference) operation.left).binding == this.binding)) { // i = i + value, then use the variable on the right hand side, since it has the correct implicit conversion variableReference.generateCompoundAssignment(currentScope, codeStream, this.syntheticAccessors == null ? null : this.syntheticAccessors[SingleNameReference.WRITE], operation.right, operator, operation.implicitConversion, valueRequired); if (valueRequired) { codeStream.generateImplicitConversion(assignment.implicitConversion); } return; } if ((operation.right instanceof SingleNameReference) && ((operator == OperatorIds.PLUS) || (operator == OperatorIds.MULTIPLY)) // only commutative operations && ((variableReference = (SingleNameReference) operation.right).binding == this.binding) && (operation.left.constant != Constant.NotAConstant) // exclude non constant expressions, since could have side-effect && (((operation.left.implicitConversion & TypeIds.IMPLICIT_CONVERSION_MASK) >> 4) != TypeIds.T_JavaLangString) // exclude string concatenation which would occur backwards && (((operation.right.implicitConversion & TypeIds.IMPLICIT_CONVERSION_MASK) >> 4) != TypeIds.T_JavaLangString)) { // exclude string concatenation which would occur backwards // i = value + i, then use the variable on the right hand side, since it has the correct implicit conversion variableReference.generateCompoundAssignment(currentScope, codeStream, this.syntheticAccessors == null ? null : this.syntheticAccessors[SingleNameReference.WRITE], operation.left, operator, operation.implicitConversion, valueRequired); if (valueRequired) { codeStream.generateImplicitConversion(assignment.implicitConversion); } return; } } switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // assigning to a field int pc = codeStream.position; FieldBinding codegenBinding = ((FieldBinding) this.binding).original(); if (!codegenBinding.isStatic()) { // need a receiver? if ((this.bits & ASTNode.DepthMASK) != 0) { ReferenceBinding targetType = currentScope.enclosingSourceType() .enclosingTypeAt((this.bits & ASTNode.DepthMASK) >> ASTNode.DepthSHIFT); Object[] emulationPath = currentScope.getEmulationPath(targetType, true /*only exact match*/, false/*consider enclosing arg*/); codeStream.generateOuterAccess(emulationPath, this, targetType, currentScope); } else { generateReceiver(codeStream); } } codeStream.recordPositionsFrom(pc, this.sourceStart); assignment.expression.generateCode(currentScope, codeStream, true); fieldStore(currentScope, codeStream, codegenBinding, this.syntheticAccessors == null ? null : this.syntheticAccessors[SingleNameReference.WRITE], this.actualReceiverType, true /*implicit this*/, valueRequired); if (valueRequired) { codeStream.generateImplicitConversion(assignment.implicitConversion); } // no need for generic cast as value got dupped return; case Binding.LOCAL: // assigning to a local variable LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; if (localBinding.resolvedPosition != -1) { assignment.expression.generateCode(currentScope, codeStream, true); } else { if (assignment.expression.constant != Constant.NotAConstant) { // assigning an unused local to a constant value = no actual assignment is necessary if (valueRequired) { codeStream.generateConstant(assignment.expression.constant, assignment.implicitConversion); } } else { assignment.expression.generateCode(currentScope, codeStream, true); /* Even though the value may not be required, we force it to be produced, and discard it later on if it was actually not necessary, so as to provide the same behavior as JDK1.2beta3. */ if (valueRequired) { codeStream.generateImplicitConversion(assignment.implicitConversion); // implicit conversion } else { switch (localBinding.type.id) { case TypeIds.T_long: case TypeIds.T_double: codeStream.pop2(); break; default: codeStream.pop(); break; } } } return; } // 26903, need extra cast to store null in array local var if (localBinding.type.isArrayType() && ((assignment.expression instanceof CastExpression) // arrayLoc = (type[])null && (((CastExpression) assignment.expression) .innermostCastedExpression().resolvedType == TypeBinding.NULL))) { codeStream.checkcast(localBinding.type); } // normal local assignment (since cannot store in outer local which are final locations) codeStream.store(localBinding, valueRequired); if ((this.bits & ASTNode.FirstAssignmentToLocal) != 0) { // for local variable debug attributes localBinding.recordInitializationStartPC(codeStream.position); } // implicit conversion if (valueRequired) { codeStream.generateImplicitConversion(assignment.implicitConversion); } } } @Override public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) { int pc = codeStream.position; if (this.constant != Constant.NotAConstant) { if (valueRequired) { codeStream.generateConstant(this.constant, this.implicitConversion); } codeStream.recordPositionsFrom(pc, this.sourceStart); return; } else { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // reading a field FieldBinding codegenField = ((FieldBinding) this.binding).original(); Constant fieldConstant = codegenField.constant(); if (fieldConstant != Constant.NotAConstant) { // directly use inlined value for constant fields if (valueRequired) { codeStream.generateConstant(fieldConstant, this.implicitConversion); } codeStream.recordPositionsFrom(pc, this.sourceStart); return; } if (codegenField.isStatic()) { if (!valueRequired // if no valueRequired, still need possible side-effects of <clinit> invocation, if field belongs to different class && TypeBinding.equalsEquals(((FieldBinding) this.binding).original().declaringClass, this.actualReceiverType.erasure()) && ((this.implicitConversion & TypeIds.UNBOXING) == 0) && this.genericCast == null) { // if no valueRequired, optimize out entire gen codeStream.recordPositionsFrom(pc, this.sourceStart); return; } // managing private access if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass( currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getstatic, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } else { if (!valueRequired && (this.implicitConversion & TypeIds.UNBOXING) == 0 && this.genericCast == null) { // if no valueRequired, optimize out entire gen codeStream.recordPositionsFrom(pc, this.sourceStart); return; } // managing enclosing instance access if ((this.bits & ASTNode.DepthMASK) != 0) { ReferenceBinding targetType = currentScope.enclosingSourceType() .enclosingTypeAt((this.bits & ASTNode.DepthMASK) >> ASTNode.DepthSHIFT); Object[] emulationPath = currentScope.getEmulationPath(targetType, true /*only exact match*/, false/*consider enclosing arg*/); codeStream.generateOuterAccess(emulationPath, this, targetType, currentScope); } else { generateReceiver(codeStream); } // managing private access if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass( currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getfield, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } break; case Binding.LOCAL: // reading a local LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; if (localBinding.resolvedPosition == -1) { if (valueRequired) { // restart code gen localBinding.useFlag = LocalVariableBinding.USED; throw new AbortMethod(CodeStream.RESTART_CODE_GEN_FOR_UNUSED_LOCALS_MODE, null); } codeStream.recordPositionsFrom(pc, this.sourceStart); return; } if (!valueRequired && (this.implicitConversion & TypeIds.UNBOXING) == 0) { // if no valueRequired, optimize out entire gen codeStream.recordPositionsFrom(pc, this.sourceStart); return; } // outer local? if ((this.bits & ASTNode.IsCapturedOuterLocal) != 0) { checkEffectiveFinality(localBinding, currentScope); // outer local can be reached either through a synthetic arg or a synthetic field VariableBinding[] path = currentScope.getEmulationPath(localBinding); codeStream.generateOuterAccess(path, this, localBinding, currentScope); } else { // regular local variable read codeStream.load(localBinding); } break; default: // type codeStream.recordPositionsFrom(pc, this.sourceStart); return; } } // required cast must occur even if no value is required if (this.genericCast != null) codeStream.checkcast(this.genericCast); if (valueRequired) { codeStream.generateImplicitConversion(this.implicitConversion); } else { boolean isUnboxing = (this.implicitConversion & TypeIds.UNBOXING) != 0; // conversion only generated if unboxing if (isUnboxing) codeStream.generateImplicitConversion(this.implicitConversion); switch (isUnboxing ? postConversionType(currentScope).id : this.resolvedType.id) { case T_long: case T_double: codeStream.pop2(); break; default: codeStream.pop(); } } codeStream.recordPositionsFrom(pc, this.sourceStart); } /* * Regular API for compound assignment, relies on the fact that there is only one reference to the * variable, which carries both synthetic read/write accessors. * The APIs with an extra argument is used whenever there are two references to the same variable which * are optimized in one access: e.g "a = a + 1" optimized into "a++". */ @Override public void generateCompoundAssignment(BlockScope currentScope, CodeStream codeStream, Expression expression, int operator, int assignmentImplicitConversion, boolean valueRequired) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=185682 switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.LOCAL: LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; // check if compound assignment is the only usage of this local Reference.reportOnlyUselesslyReadLocal(currentScope, localBinding, valueRequired); break; case Binding.FIELD: // check if compound assignment is the only usage of a private field reportOnlyUselesslyReadPrivateField(currentScope, (FieldBinding) this.binding, valueRequired); } this.generateCompoundAssignment(currentScope, codeStream, this.syntheticAccessors == null ? null : this.syntheticAccessors[SingleNameReference.WRITE], expression, operator, assignmentImplicitConversion, valueRequired); } /* * The APIs with an extra argument is used whenever there are two references to the same variable which * are optimized in one access: e.g "a = a + 1" optimized into "a++". */ public void generateCompoundAssignment(BlockScope currentScope, CodeStream codeStream, MethodBinding writeAccessor, Expression expression, int operator, int assignmentImplicitConversion, boolean valueRequired) { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // assigning to a field FieldBinding codegenField = ((FieldBinding) this.binding).original(); if (codegenField.isStatic()) { if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getstatic, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } else { if ((this.bits & ASTNode.DepthMASK) != 0) { ReferenceBinding targetType = currentScope.enclosingSourceType() .enclosingTypeAt((this.bits & ASTNode.DepthMASK) >> ASTNode.DepthSHIFT); Object[] emulationPath = currentScope.getEmulationPath(targetType, true /*only exact match*/, false/*consider enclosing arg*/); codeStream.generateOuterAccess(emulationPath, this, targetType, currentScope); } else { codeStream.aload_0(); } codeStream.dup(); if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getfield, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } break; case Binding.LOCAL: // assigning to a local variable (cannot assign to outer local) LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; // using incr bytecode if possible Constant assignConstant; switch (localBinding.type.id) { case T_JavaLangString: codeStream.generateStringConcatenationAppend(currentScope, this, expression); if (valueRequired) { codeStream.dup(); } codeStream.store(localBinding, false); return; case T_int: assignConstant = expression.constant; if (localBinding.resolvedPosition == -1) { if (valueRequired) { /* * restart code gen because we either: * - need the value * - the constant can have potential side-effect */ localBinding.useFlag = LocalVariableBinding.USED; throw new AbortMethod(CodeStream.RESTART_CODE_GEN_FOR_UNUSED_LOCALS_MODE, null); } else if (assignConstant == Constant.NotAConstant) { // we only need to generate the value of the expression's constant if it is not a constant expression expression.generateCode(currentScope, codeStream, false); } return; } if ((assignConstant != Constant.NotAConstant) && (assignConstant.typeID() != TypeIds.T_float) // only for integral types && (assignConstant.typeID() != TypeIds.T_double)) { // TODO (philippe) is this test needed ? switch (operator) { case PLUS: int increment = assignConstant.intValue(); if (increment != (short) increment) break; // not representable as a 16-bits value codeStream.iinc(localBinding.resolvedPosition, increment); if (valueRequired) { codeStream.load(localBinding); } return; case MINUS: increment = -assignConstant.intValue(); if (increment != (short) increment) break; // not representable as a 16-bits value codeStream.iinc(localBinding.resolvedPosition, increment); if (valueRequired) { codeStream.load(localBinding); } return; } } //$FALL-THROUGH$ default: if (localBinding.resolvedPosition == -1) { assignConstant = expression.constant; if (valueRequired) { /* * restart code gen because we either: * - need the value * - the constant can have potential side-effect */ localBinding.useFlag = LocalVariableBinding.USED; throw new AbortMethod(CodeStream.RESTART_CODE_GEN_FOR_UNUSED_LOCALS_MODE, null); } else if (assignConstant == Constant.NotAConstant) { // we only need to generate the value of the expression's constant if it is not a constant expression expression.generateCode(currentScope, codeStream, false); } return; } codeStream.load(localBinding); } } // perform the actual compound operation int operationTypeID; switch (operationTypeID = (this.implicitConversion & TypeIds.IMPLICIT_CONVERSION_MASK) >> 4) { case T_JavaLangString: case T_JavaLangObject: case T_undefined: // we enter here if the single name reference is a field of type java.lang.String or if the type of the // operation is java.lang.Object // For example: o = o + ""; // where the compiled type of o is java.lang.Object. codeStream.generateStringConcatenationAppend(currentScope, null, expression); // no need for generic cast on previous #getfield since using Object string buffer methods. break; default: // promote the array reference to the suitable operation type if (this.genericCast != null) codeStream.checkcast(this.genericCast); codeStream.generateImplicitConversion(this.implicitConversion); // generate the increment value (will by itself be promoted to the operation value) if (expression == IntLiteral.One) { // prefix operation codeStream.generateConstant(expression.constant, this.implicitConversion); } else { expression.generateCode(currentScope, codeStream, true); } // perform the operation codeStream.sendOperator(operator, operationTypeID); // cast the value back to the array reference type codeStream.generateImplicitConversion(assignmentImplicitConversion); } // store the result back into the variable switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // assigning to a field FieldBinding codegenField = ((FieldBinding) this.binding).original(); fieldStore(currentScope, codeStream, codegenField, writeAccessor, this.actualReceiverType, true /* implicit this*/, valueRequired); // no need for generic cast as value got dupped return; case Binding.LOCAL: // assigning to a local variable LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; if (valueRequired) { switch (localBinding.type.id) { case TypeIds.T_long: case TypeIds.T_double: codeStream.dup2(); break; default: codeStream.dup(); break; } } codeStream.store(localBinding, false); } } @Override public void generatePostIncrement(BlockScope currentScope, CodeStream codeStream, CompoundAssignment postIncrement, boolean valueRequired) { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // assigning to a field FieldBinding fieldBinding = (FieldBinding) this.binding; // https://bugs.eclipse.org/bugs/show_bug.cgi?id=185682 // check if postIncrement is the only usage of a private field reportOnlyUselesslyReadPrivateField(currentScope, fieldBinding, valueRequired); FieldBinding codegenField = fieldBinding.original(); if (codegenField.isStatic()) { if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getstatic, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } else { if ((this.bits & ASTNode.DepthMASK) != 0) { ReferenceBinding targetType = currentScope.enclosingSourceType() .enclosingTypeAt((this.bits & ASTNode.DepthMASK) >> ASTNode.DepthSHIFT); Object[] emulationPath = currentScope.getEmulationPath(targetType, true /*only exact match*/, false/*consider enclosing arg*/); codeStream.generateOuterAccess(emulationPath, this, targetType, currentScope); } else { codeStream.aload_0(); } codeStream.dup(); if ((this.syntheticAccessors == null) || (this.syntheticAccessors[SingleNameReference.READ] == null)) { TypeBinding constantPoolDeclaringClass = CodeStream.getConstantPoolDeclaringClass(currentScope, codegenField, this.actualReceiverType, true /* implicit this */); codeStream.fieldAccess(Opcodes.OPC_getfield, codegenField, constantPoolDeclaringClass); } else { codeStream.invoke(Opcodes.OPC_invokestatic, this.syntheticAccessors[SingleNameReference.READ], null /* default declaringClass */); } } TypeBinding operandType; if (this.genericCast != null) { codeStream.checkcast(this.genericCast); operandType = this.genericCast; } else { operandType = codegenField.type; } if (valueRequired) { if (codegenField.isStatic()) { switch (operandType.id) { case TypeIds.T_long: case TypeIds.T_double: codeStream.dup2(); break; default: codeStream.dup(); break; } } else { // Stack: [owner][old field value] ---> [old field value][owner][old field value] switch (operandType.id) { case TypeIds.T_long: case TypeIds.T_double: codeStream.dup2_x1(); break; default: codeStream.dup_x1(); break; } } } codeStream.generateImplicitConversion(this.implicitConversion); codeStream.generateConstant(postIncrement.expression.constant, this.implicitConversion); codeStream.sendOperator(postIncrement.operator, this.implicitConversion & TypeIds.COMPILE_TYPE_MASK); codeStream.generateImplicitConversion(postIncrement.preAssignImplicitConversion); fieldStore(currentScope, codeStream, codegenField, this.syntheticAccessors == null ? null : this.syntheticAccessors[SingleNameReference.WRITE], this.actualReceiverType, true /*implicit this*/, false); // no need for generic cast return; case Binding.LOCAL: // assigning to a local variable LocalVariableBinding localBinding = (LocalVariableBinding) this.binding; // https://bugs.eclipse.org/bugs/show_bug.cgi?id=185682 // check if postIncrement is the only usage of this local Reference.reportOnlyUselesslyReadLocal(currentScope, localBinding, valueRequired); if (localBinding.resolvedPosition == -1) { if (valueRequired) { // restart code gen localBinding.useFlag = LocalVariableBinding.USED; throw new AbortMethod(CodeStream.RESTART_CODE_GEN_FOR_UNUSED_LOCALS_MODE, null); } return; } // using incr bytecode if possible if (TypeBinding.equalsEquals(localBinding.type, TypeBinding.INT)) { if (valueRequired) { codeStream.load(localBinding); } if (postIncrement.operator == OperatorIds.PLUS) { codeStream.iinc(localBinding.resolvedPosition, 1); } else { codeStream.iinc(localBinding.resolvedPosition, -1); } } else { codeStream.load(localBinding); if (valueRequired) { switch (localBinding.type.id) { case TypeIds.T_long: case TypeIds.T_double: codeStream.dup2(); break; default: codeStream.dup(); break; } } codeStream.generateImplicitConversion(this.implicitConversion); codeStream.generateConstant(postIncrement.expression.constant, this.implicitConversion); codeStream.sendOperator(postIncrement.operator, this.implicitConversion & TypeIds.COMPILE_TYPE_MASK); codeStream.generateImplicitConversion(postIncrement.preAssignImplicitConversion); codeStream.store(localBinding, false); } } } public void generateReceiver(CodeStream codeStream) { codeStream.aload_0(); } /** * @see org.eclipse.jdt.internal.compiler.lookup.InvocationSite#genericTypeArguments() */ @Override public TypeBinding[] genericTypeArguments() { return null; } @Override public boolean isEquivalent(Reference reference) { char[] otherToken = null; if (reference instanceof SingleNameReference) { otherToken = ((SingleNameReference) reference).token; } else if (reference instanceof FieldReference) { // test for comparison "f1" vs. "this.f1": FieldReference fr = (FieldReference) reference; if (fr.receiver.isThis() && !(fr.receiver instanceof QualifiedThisReference)) otherToken = fr.token; } return otherToken != null && CharOperation.equals(this.token, otherToken); } /** * Returns the local variable referenced by this node. Can be a direct reference (SingleNameReference) * or thru a cast expression etc... */ @Override public LocalVariableBinding localVariableBinding() { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // reading a field break; case Binding.LOCAL: // reading a local variable return (LocalVariableBinding) this.binding; } return null; } @Override public VariableBinding nullAnnotatedVariableBinding(boolean supportTypeAnnotations) { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.FIELD: // reading a field case Binding.LOCAL: // reading a local variable if (supportTypeAnnotations || (((VariableBinding) this.binding).tagBits & TagBits.AnnotationNullMASK) != 0) return (VariableBinding) this.binding; } return null; } @Override public int nullStatus(FlowInfo flowInfo, FlowContext flowContext) { if ((this.implicitConversion & TypeIds.BOXING) != 0) return FlowInfo.NON_NULL; LocalVariableBinding local = localVariableBinding(); if (local != null) { return flowInfo.nullStatus(local); } return super.nullStatus(flowInfo, flowContext); } public void manageEnclosingInstanceAccessIfNecessary(BlockScope currentScope, FlowInfo flowInfo) { //If inlinable field, forget the access emulation, the code gen will directly target it if (((this.bits & ASTNode.DepthMASK) == 0 && (this.bits & ASTNode.IsCapturedOuterLocal) == 0) || (this.constant != Constant.NotAConstant)) { return; } if ((this.bits & ASTNode.RestrictiveFlagMASK) == Binding.LOCAL) { LocalVariableBinding localVariableBinding = (LocalVariableBinding) this.binding; if (localVariableBinding != null) { if (localVariableBinding.isUninitializedIn(currentScope)) { // local was tagged as uninitialized return; } if ((localVariableBinding.tagBits & TagBits.IsEffectivelyFinal) == 0) { // local was tagged as not effectively final return; } switch (localVariableBinding.useFlag) { case LocalVariableBinding.FAKE_USED: case LocalVariableBinding.USED: currentScope.emulateOuterAccess(localVariableBinding); } } } } public void manageSyntheticAccessIfNecessary(BlockScope currentScope, FlowInfo flowInfo, boolean isReadAccess) { if ((flowInfo.tagBits & FlowInfo.UNREACHABLE_OR_DEAD) != 0) return; //If inlinable field, forget the access emulation, the code gen will directly target it if (this.constant != Constant.NotAConstant) return; if ((this.bits & Binding.FIELD) != 0) { FieldBinding fieldBinding = (FieldBinding) this.binding; FieldBinding codegenField = fieldBinding.original(); if (((this.bits & ASTNode.DepthMASK) != 0) && ((codegenField.isPrivate() // private access && !currentScope.enclosingSourceType().isNestmateOf(codegenField.declaringClass)) || (codegenField.isProtected() // implicit protected access && codegenField.declaringClass.getPackage() != currentScope.enclosingSourceType() .getPackage()))) { if (this.syntheticAccessors == null) this.syntheticAccessors = new MethodBinding[2]; this.syntheticAccessors[isReadAccess ? SingleNameReference.READ : SingleNameReference.WRITE] = ((SourceTypeBinding) currentScope.enclosingSourceType() .enclosingTypeAt((this.bits & ASTNode.DepthMASK) >> ASTNode.DepthSHIFT)) .addSyntheticMethod(codegenField, isReadAccess, false /*not super access*/); currentScope.problemReporter().needToEmulateFieldAccess(codegenField, this, isReadAccess); return; } } } /** * @see org.eclipse.jdt.internal.compiler.ast.Expression#postConversionType(Scope) */ @Override public TypeBinding postConversionType(Scope scope) { TypeBinding convertedType = this.resolvedType; if (this.genericCast != null) convertedType = this.genericCast; int runtimeType = (this.implicitConversion & TypeIds.IMPLICIT_CONVERSION_MASK) >> 4; switch (runtimeType) { case T_boolean: convertedType = TypeBinding.BOOLEAN; break; case T_byte: convertedType = TypeBinding.BYTE; break; case T_short: convertedType = TypeBinding.SHORT; break; case T_char: convertedType = TypeBinding.CHAR; break; case T_int: convertedType = TypeBinding.INT; break; case T_float: convertedType = TypeBinding.FLOAT; break; case T_long: convertedType = TypeBinding.LONG; break; case T_double: convertedType = TypeBinding.DOUBLE; break; default: } if ((this.implicitConversion & TypeIds.BOXING) != 0) { convertedType = scope.environment().computeBoxingType(convertedType); } return convertedType; } @Override public StringBuffer printExpression(int indent, StringBuffer output) { return output.append(this.token); } public TypeBinding reportError(BlockScope scope) { //=====error cases======= this.constant = Constant.NotAConstant; if (this.binding instanceof ProblemFieldBinding) { scope.problemReporter().invalidField(this, (FieldBinding) this.binding); } else if (this.binding instanceof ProblemReferenceBinding || this.binding instanceof MissingTypeBinding) { scope.problemReporter().invalidType(this, (TypeBinding) this.binding); } else { scope.problemReporter().unresolvableReference(this, this.binding); } return null; } @Override public TypeBinding resolveType(BlockScope scope) { // for code gen, harm the restrictiveFlag if (this.actualReceiverType != null) { this.binding = scope.getField(this.actualReceiverType, this.token, this); } else { this.actualReceiverType = scope.enclosingSourceType(); this.binding = scope.getBinding(this.token, this.bits & ASTNode.RestrictiveFlagMASK, this, true /*resolve*/); } if (this.binding.isValidBinding()) { switch (this.bits & ASTNode.RestrictiveFlagMASK) { case Binding.VARIABLE: // =========only variable============ case Binding.VARIABLE | Binding.TYPE: //====both variable and type============ if (this.binding instanceof VariableBinding) { VariableBinding variable = (VariableBinding) this.binding; TypeBinding variableType; if (this.binding instanceof LocalVariableBinding) { this.bits &= ~ASTNode.RestrictiveFlagMASK; // clear bits this.bits |= Binding.LOCAL; ((LocalVariableBinding) this.binding).markReferenced(); if (!variable.isFinal() && (this.bits & ASTNode.IsCapturedOuterLocal) != 0) { if (scope.compilerOptions().sourceLevel < ClassFileConstants.JDK1_8) // for 8, defer till effective finality could be ascertained. scope.problemReporter() .cannotReferToNonFinalOuterLocal((LocalVariableBinding) variable, this); } variableType = variable.type; this.constant = (this.bits & ASTNode.IsStrictlyAssigned) == 0 ? variable.constant(scope) : Constant.NotAConstant; } else { // a field variableType = checkFieldAccess(scope); } // perform capture conversion if read access if (variableType != null) { this.resolvedType = variableType = (((this.bits & ASTNode.IsStrictlyAssigned) == 0) ? variableType.capture(scope, this.sourceStart, this.sourceEnd) : variableType); if ((variableType.tagBits & TagBits.HasMissingType) != 0) { if ((this.bits & Binding.LOCAL) == 0) { // only complain if field reference (for local, its type got flagged already) scope.problemReporter().invalidType(this, variableType); } return null; } } return variableType; } // thus it was a type this.bits &= ~ASTNode.RestrictiveFlagMASK; // clear bits this.bits |= Binding.TYPE; //$FALL-THROUGH$ case Binding.TYPE: //========only type============== this.constant = Constant.NotAConstant; //deprecated test TypeBinding type = (TypeBinding) this.binding; if (isTypeUseDeprecated(type, scope)) scope.problemReporter().deprecatedType(type, this); type = scope.environment().convertToRawType(type, false /*do not force conversion of enclosing types*/); return this.resolvedType = type; } } // error scenario return this.resolvedType = reportError(scope); } @Override public void traverse(ASTVisitor visitor, BlockScope scope) { visitor.visit(this, scope); visitor.endVisit(this, scope); } @Override public void traverse(ASTVisitor visitor, ClassScope scope) { visitor.visit(this, scope); visitor.endVisit(this, scope); } @Override public String unboundReferenceErrorName() { return new String(this.token); } @Override public char[][] getName() { return new char[][] { this.token }; } }