+++ /dev/null
-/*******************************************************************************
- * Copyright (c) 2000, 2004 IBM Corporation and others.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Common Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/cpl-v10.html
- *
- * Contributors:
- * IBM Corporation - initial API and implementation
- *******************************************************************************/
-package org.eclipse.jdt.internal.compiler.ast;
-
-import org.eclipse.jdt.internal.compiler.ASTVisitor;
-import org.eclipse.jdt.internal.compiler.codegen.*;
-import org.eclipse.jdt.internal.compiler.flow.*;
-import org.eclipse.jdt.internal.compiler.lookup.*;
-
-public class TryStatement extends SubRoutineStatement {
-
- public Block tryBlock;
- public Block[] catchBlocks;
- public Argument[] catchArguments;
- public Block finallyBlock;
- BlockScope scope;
-
- private boolean isSubRoutineEscaping = false;
- public UnconditionalFlowInfo subRoutineInits;
-
- // should rename into subRoutineComplete to be set to false by default
-
- ReferenceBinding[] caughtExceptionTypes;
- boolean tryBlockExit;
- boolean[] catchExits;
- public int[] preserveExceptionHandler;
-
- Label subRoutineStartLabel;
- public LocalVariableBinding anyExceptionVariable,
- returnAddressVariable,
- secretReturnValue;
-
- public final static char[] SecretReturnName = " returnAddress".toCharArray(); //$NON-NLS-1$
- public final static char[] SecretAnyHandlerName = " anyExceptionHandler".toCharArray(); //$NON-NLS-1$
- public static final char[] SecretLocalDeclarationName = " returnValue".toCharArray(); //$NON-NLS-1$
-
- // for local variables table attributes
- int preTryInitStateIndex = -1;
- int mergedInitStateIndex = -1;
-
- public FlowInfo analyseCode(
- BlockScope currentScope,
- FlowContext flowContext,
- FlowInfo flowInfo) {
-
- // Consider the try block and catch block so as to compute the intersection of initializations and
- // the minimum exit relative depth amongst all of them. Then consider the subroutine, and append its
- // initialization to the try/catch ones, if the subroutine completes normally. If the subroutine does not
- // complete, then only keep this result for the rest of the analysis
-
- // process the finally block (subroutine) - create a context for the subroutine
-
- preTryInitStateIndex =
- currentScope.methodScope().recordInitializationStates(flowInfo);
-
- if (anyExceptionVariable != null) {
- anyExceptionVariable.useFlag = LocalVariableBinding.USED;
- }
- if (returnAddressVariable != null) { // TODO (philippe) if subroutine is escaping, unused
- returnAddressVariable.useFlag = LocalVariableBinding.USED;
- }
- InsideSubRoutineFlowContext insideSubContext;
- FinallyFlowContext finallyContext;
- UnconditionalFlowInfo subInfo;
- if (subRoutineStartLabel == null) {
- // no finally block
- insideSubContext = null;
- finallyContext = null;
- subInfo = null;
- } else {
- // analyse finally block first
- insideSubContext = new InsideSubRoutineFlowContext(flowContext, this);
- subInfo =
- finallyBlock
- .analyseCode(
- currentScope,
- finallyContext = new FinallyFlowContext(flowContext, finallyBlock),
- flowInfo.copy())
- .unconditionalInits();
- if (subInfo == FlowInfo.DEAD_END) {
- isSubRoutineEscaping = true;
- scope.problemReporter().finallyMustCompleteNormally(finallyBlock);
- }
- this.subRoutineInits = subInfo;
- }
- // process the try block in a context handling the local exceptions.
- ExceptionHandlingFlowContext handlingContext =
- new ExceptionHandlingFlowContext(
- insideSubContext == null ? flowContext : insideSubContext,
- tryBlock,
- caughtExceptionTypes,
- scope,
- flowInfo.unconditionalInits());
-
- FlowInfo tryInfo;
- if (tryBlock.isEmptyBlock()) {
- tryInfo = flowInfo;
- tryBlockExit = false;
- } else {
- tryInfo = tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
- tryBlockExit = !tryInfo.isReachable();
- }
-
- // check unreachable catch blocks
- handlingContext.complainIfUnusedExceptionHandlers(scope, this);
-
- // process the catch blocks - computing the minimal exit depth amongst try/catch
- if (catchArguments != null) {
- int catchCount;
- catchExits = new boolean[catchCount = catchBlocks.length];
- for (int i = 0; i < catchCount; i++) {
- // keep track of the inits that could potentially have led to this exception handler (for final assignments diagnosis)
- FlowInfo catchInfo =
- flowInfo
- .copy()
- .unconditionalInits()
- .addPotentialInitializationsFrom(
- handlingContext.initsOnException(caughtExceptionTypes[i]).unconditionalInits())
- .addPotentialInitializationsFrom(tryInfo.unconditionalInits())
- .addPotentialInitializationsFrom(handlingContext.initsOnReturn);
-
- // catch var is always set
- catchInfo.markAsDefinitelyAssigned(catchArguments[i].binding);
- /*
- "If we are about to consider an unchecked exception handler, potential inits may have occured inside
- the try block that need to be detected , e.g.
- try { x = 1; throwSomething();} catch(Exception e){ x = 2} "
- "(uncheckedExceptionTypes notNil and: [uncheckedExceptionTypes at: index])
- ifTrue: [catchInits addPotentialInitializationsFrom: tryInits]."
- */
- // TODO (philippe) should only tag as unreachable if the catchblock cannot be reached?
- //??? if (!handlingContext.initsOnException(caughtExceptionTypes[i]).isReachable()){
- if (tryBlock.statements == null) {
- catchInfo.setReachMode(FlowInfo.UNREACHABLE);
- }
- catchInfo =
- catchBlocks[i].analyseCode(
- currentScope,
- insideSubContext == null ? flowContext : insideSubContext,
- catchInfo);
- catchExits[i] = !catchInfo.isReachable();
- tryInfo = tryInfo.mergedWith(catchInfo.unconditionalInits());
- }
- }
- if (subRoutineStartLabel == null) {
- mergedInitStateIndex =
- currentScope.methodScope().recordInitializationStates(tryInfo);
- return tryInfo;
- }
-
-
- // we also need to check potential multiple assignments of final variables inside the finally block
- // need to include potential inits from returns inside the try/catch parts - 1GK2AOF
- finallyContext.complainOnRedundantFinalAssignments(
- tryInfo.isReachable()
- ? (tryInfo.addPotentialInitializationsFrom(insideSubContext.initsOnReturn))
- : insideSubContext.initsOnReturn,
- currentScope);
- if (subInfo == FlowInfo.DEAD_END) {
- mergedInitStateIndex =
- currentScope.methodScope().recordInitializationStates(subInfo);
- return subInfo;
- } else {
- FlowInfo mergedInfo = tryInfo.addInitializationsFrom(subInfo);
- mergedInitStateIndex =
- currentScope.methodScope().recordInitializationStates(mergedInfo);
- return mergedInfo;
- }
- }
-
- public boolean isSubRoutineEscaping() {
-
- return isSubRoutineEscaping;
- }
-
- /**
- * Try statement code generation with or without jsr bytecode use
- * post 1.5 target level, cannot use jsr bytecode, must instead inline finally block
- * returnAddress is only allocated if jsr is allowed
- */
- public void generateCode(BlockScope currentScope, CodeStream codeStream) {
-
- if ((bits & IsReachableMASK) == 0) {
- return;
- }
- // in case the labels needs to be reinitialized
- // when the code generation is restarted in wide mode
- if (this.anyExceptionLabelsCount > 0) {
- this.anyExceptionLabels = NO_EXCEPTION_HANDLER;
- this.anyExceptionLabelsCount = 0;
- }
- int pc = codeStream.position;
- final int NO_FINALLY = 0; // no finally block
- final int FINALLY_SUBROUTINE = 1; // finally is generated as a subroutine (using jsr/ret bytecodes)
- final int FINALLY_DOES_NOT_COMPLETE = 2; // non returning finally is optimized with only one instance of finally block
- final int FINALLY_MUST_BE_INLINED = 3; // finally block must be inlined since cannot use jsr/ret bytecodes >1.5
- int finallyMode;
- if (subRoutineStartLabel == null) {
- finallyMode = NO_FINALLY;
- } else {
- if (this.isSubRoutineEscaping) {
- finallyMode = FINALLY_DOES_NOT_COMPLETE;
- } else if (scope.environment().options.inlineJsrBytecode) {
- finallyMode = FINALLY_MUST_BE_INLINED;
- } else {
- finallyMode = FINALLY_SUBROUTINE;
- }
- }
- boolean requiresNaturalExit = false;
- // preparing exception labels
- int maxCatches;
- ExceptionLabel[] exceptionLabels =
- new ExceptionLabel[maxCatches =
- catchArguments == null ? 0 : catchArguments.length];
- for (int i = 0; i < maxCatches; i++) {
- exceptionLabels[i] = new ExceptionLabel(codeStream, catchArguments[i].binding.type);
- }
- if (subRoutineStartLabel != null) {
- subRoutineStartLabel.initialize(codeStream);
- this.enterAnyExceptionHandler(codeStream);
- }
- // generate the try block
- tryBlock.generateCode(scope, codeStream);
- boolean tryBlockHasSomeCode = codeStream.position != pc;
- // flag telling if some bytecodes were issued inside the try block
-
- // place end positions of user-defined exception labels
- if (tryBlockHasSomeCode) {
- // natural exit may require subroutine invocation (if finally != null)
- Label naturalExitLabel = new Label(codeStream);
- if (!tryBlockExit) {
- int position = codeStream.position;
- switch(finallyMode) {
- case FINALLY_SUBROUTINE :
- case FINALLY_MUST_BE_INLINED :
- requiresNaturalExit = true;
- // fall through
- case NO_FINALLY :
- codeStream.goto_(naturalExitLabel);
- break;
- case FINALLY_DOES_NOT_COMPLETE :
- codeStream.goto_(subRoutineStartLabel);
- break;
- }
- codeStream.updateLastRecordedEndPC(position);
- //goto is tagged as part of the try block
- }
- for (int i = 0; i < maxCatches; i++) {
- exceptionLabels[i].placeEnd();
- }
- /* generate sequence of handler, all starting by storing the TOS (exception
- thrown) into their own catch variables, the one specified in the source
- that must denote the handled exception.
- */
- if (catchArguments == null) {
- this.exitAnyExceptionHandler();
- } else {
- for (int i = 0; i < maxCatches; i++) {
- // May loose some local variable initializations : affecting the local variable attributes
- if (preTryInitStateIndex != -1) {
- codeStream.removeNotDefinitelyAssignedVariables(
- currentScope,
- preTryInitStateIndex);
- }
- exceptionLabels[i].place();
- codeStream.incrStackSize(1);
- // optimizing the case where the exception variable is not actually used
- LocalVariableBinding catchVar;
- int varPC = codeStream.position;
- if ((catchVar = catchArguments[i].binding).resolvedPosition != -1) {
- codeStream.store(catchVar, false);
- catchVar.recordInitializationStartPC(codeStream.position);
- codeStream.addVisibleLocalVariable(catchVar);
- } else {
- codeStream.pop();
- }
- codeStream.recordPositionsFrom(varPC, catchArguments[i].sourceStart);
- // Keep track of the pcs at diverging point for computing the local attribute
- // since not passing the catchScope, the block generation will exitUserScope(catchScope)
- catchBlocks[i].generateCode(scope, codeStream);
-
- if (i == maxCatches - 1) {
- this.exitAnyExceptionHandler();
- }
- if (!catchExits[i]) {
- switch(finallyMode) {
- case FINALLY_SUBROUTINE :
- case FINALLY_MUST_BE_INLINED :
- requiresNaturalExit = true;
- // fall through
- case NO_FINALLY :
- codeStream.goto_(naturalExitLabel);
- break;
- case FINALLY_DOES_NOT_COMPLETE :
- codeStream.goto_(subRoutineStartLabel);
- break;
- }
- }
- }
- }
- // extra handler for trailing natural exit (will be fixed up later on when natural exit is generated below)
- ExceptionLabel naturalExitExceptionHandler =
- finallyMode == FINALLY_SUBROUTINE && requiresNaturalExit ? this.enterAnyExceptionHandler(codeStream) : null;
-
- // addition of a special handler so as to ensure that any uncaught exception (or exception thrown
- // inside catch blocks) will run the finally block
- int finallySequenceStartPC = codeStream.position;
- if (subRoutineStartLabel != null) {
- // the additional handler is doing: jsr finallyBlock and rethrow TOS-exception
- this.placeAllAnyExceptionHandlers();
-
- if (preTryInitStateIndex != -1) {
- // reset initialization state, as for a normal catch block
- codeStream.removeNotDefinitelyAssignedVariables(
- currentScope,
- preTryInitStateIndex);
- }
-
- codeStream.incrStackSize(1);
- switch(finallyMode) {
-
- case FINALLY_SUBROUTINE :
- codeStream.store(anyExceptionVariable, false);
- codeStream.jsr(subRoutineStartLabel);
- codeStream.load(anyExceptionVariable);
- codeStream.athrow();
- subRoutineStartLabel.place();
- codeStream.incrStackSize(1);
- codeStream.store(returnAddressVariable, false);
- codeStream.recordPositionsFrom(finallySequenceStartPC, finallyBlock.sourceStart);
- finallyBlock.generateCode(scope, codeStream);
- int position = codeStream.position;
- codeStream.ret(returnAddressVariable.resolvedPosition);
- codeStream.updateLastRecordedEndPC(position);
- codeStream.recordPositionsFrom(
- position,
- finallyBlock.sourceEnd);
- // the ret bytecode is part of the subroutine
- break;
-
- case FINALLY_MUST_BE_INLINED :
- codeStream.store(anyExceptionVariable, false);
- this.finallyBlock.generateCode(currentScope, codeStream);
- codeStream.load(anyExceptionVariable);
- codeStream.athrow();
- subRoutineStartLabel.place();
- codeStream.recordPositionsFrom(finallySequenceStartPC, finallyBlock.sourceStart);
- break;
-
- case FINALLY_DOES_NOT_COMPLETE :
- codeStream.pop();
- subRoutineStartLabel.place();
- codeStream.recordPositionsFrom(finallySequenceStartPC, finallyBlock.sourceStart);
- finallyBlock.generateCode(scope, codeStream);
- break;
- }
- // will naturally fall into subsequent code after subroutine invocation
- naturalExitLabel.place();
- if (requiresNaturalExit) {
- switch(finallyMode) {
-
- case FINALLY_SUBROUTINE :
- int position = codeStream.position;
- // fix up natural exit handler
- naturalExitExceptionHandler.placeStart();
- codeStream.jsr(subRoutineStartLabel);
- naturalExitExceptionHandler.placeEnd();
- codeStream.recordPositionsFrom(
- position,
- finallyBlock.sourceStart);
- break;
-
- case FINALLY_MUST_BE_INLINED :
- // May loose some local variable initializations : affecting the local variable attributes
- // needed since any exception handler got inlined subroutine
- if (preTryInitStateIndex != -1) {
- codeStream.removeNotDefinitelyAssignedVariables(
- currentScope,
- preTryInitStateIndex);
- }
- // entire sequence for finally is associated to finally block
- finallyBlock.generateCode(scope, codeStream);
- break;
-
- case FINALLY_DOES_NOT_COMPLETE :
- break;
- }
- }
- } else {
- // no subroutine, simply position end label (natural exit == end)
- naturalExitLabel.place();
- }
- } else {
- // try block had no effect, only generate the body of the finally block if any
- if (subRoutineStartLabel != null) {
- finallyBlock.generateCode(scope, codeStream);
- }
- }
- // May loose some local variable initializations : affecting the local variable attributes
- if (mergedInitStateIndex != -1) {
- codeStream.removeNotDefinitelyAssignedVariables(
- currentScope,
- mergedInitStateIndex);
- codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
- }
- codeStream.recordPositionsFrom(pc, this.sourceStart);
- }
-
- /* (non-Javadoc)
- * @see org.eclipse.jdt.internal.compiler.ast.SubRoutineStatement#generateSubRoutineInvocation(org.eclipse.jdt.internal.compiler.lookup.BlockScope, org.eclipse.jdt.internal.compiler.codegen.CodeStream)
- */
- public void generateSubRoutineInvocation(
- BlockScope currentScope,
- CodeStream codeStream) {
-
- if (this.isSubRoutineEscaping) {
- codeStream.goto_(this.subRoutineStartLabel);
- } else {
- if (currentScope.environment().options.inlineJsrBytecode) {
- // cannot use jsr bytecode, then simply inline the subroutine
- this.finallyBlock.generateCode(currentScope, codeStream);
- } else {
- // classic subroutine invocation, distinguish case of non-returning subroutine
- codeStream.jsr(this.subRoutineStartLabel);
- }
- }
- }
-
- public StringBuffer printStatement(int indent, StringBuffer output) {
- printIndent(indent, output).append("try \n"); //$NON-NLS-1$
- tryBlock.printStatement(indent + 1, output); //$NON-NLS-1$
-
- //catches
- if (catchBlocks != null)
- for (int i = 0; i < catchBlocks.length; i++) {
- output.append('\n');
- printIndent(indent, output).append("catch ("); //$NON-NLS-1$
- catchArguments[i].print(0, output).append(") "); //$NON-NLS-1$
- catchBlocks[i].printStatement(indent + 1, output);
- }
- //finally
- if (finallyBlock != null) {
- output.append('\n');
- printIndent(indent, output).append("finally\n"); //$NON-NLS-1$
- finallyBlock.printStatement(indent + 1, output);
- }
-
- return output;
- }
-
- public void resolve(BlockScope upperScope) {
-
- // special scope for secret locals optimization.
- this.scope = new BlockScope(upperScope);
-
- BlockScope tryScope = new BlockScope(scope);
- BlockScope finallyScope = null;
-
- if (finallyBlock != null) {
- if (finallyBlock.isEmptyBlock()) {
- if ((finallyBlock.bits & UndocumentedEmptyBlockMASK) != 0) {
- scope.problemReporter().undocumentedEmptyBlock(finallyBlock.sourceStart, finallyBlock.sourceEnd);
- }
- } else {
- finallyScope = new BlockScope(scope, false); // don't add it yet to parent scope
-
- // provision for returning and forcing the finally block to run
- MethodScope methodScope = scope.methodScope();
-
- // the type does not matter as long as it is not a base type
- if (!upperScope.environment().options.inlineJsrBytecode) {
- this.returnAddressVariable =
- new LocalVariableBinding(SecretReturnName, upperScope.getJavaLangObject(), AccDefault, false);
- finallyScope.addLocalVariable(returnAddressVariable);
- this.returnAddressVariable.constant = NotAConstant; // not inlinable
- }
- this.subRoutineStartLabel = new Label();
-
- this.anyExceptionVariable =
- new LocalVariableBinding(SecretAnyHandlerName, scope.getJavaLangThrowable(), AccDefault, false);
- finallyScope.addLocalVariable(this.anyExceptionVariable);
- this.anyExceptionVariable.constant = NotAConstant; // not inlinable
-
- if (!methodScope.isInsideInitializer()) {
- MethodBinding methodBinding =
- ((AbstractMethodDeclaration) methodScope.referenceContext).binding;
- if (methodBinding != null) {
- TypeBinding methodReturnType = methodBinding.returnType;
- if (methodReturnType.id != T_void) {
- this.secretReturnValue =
- new LocalVariableBinding(
- SecretLocalDeclarationName,
- methodReturnType,
- AccDefault,
- false);
- finallyScope.addLocalVariable(this.secretReturnValue);
- this.secretReturnValue.constant = NotAConstant; // not inlinable
- }
- }
- }
- finallyBlock.resolveUsing(finallyScope);
- // force the finally scope to have variable positions shifted after its try scope and catch ones
- finallyScope.shiftScopes = new BlockScope[catchArguments == null ? 1 : catchArguments.length+1];
- finallyScope.shiftScopes[0] = tryScope;
- }
- }
- this.tryBlock.resolveUsing(tryScope);
-
- // arguments type are checked against JavaLangThrowable in resolveForCatch(..)
- if (this.catchBlocks != null) {
- int length = this.catchArguments.length;
- TypeBinding[] argumentTypes = new TypeBinding[length];
- for (int i = 0; i < length; i++) {
- BlockScope catchScope = new BlockScope(scope);
- if (finallyScope != null){
- finallyScope.shiftScopes[i+1] = catchScope;
- }
- // side effect on catchScope in resolveForCatch(..)
- if ((argumentTypes[i] = catchArguments[i].resolveForCatch(catchScope)) == null)
- return;
- catchBlocks[i].resolveUsing(catchScope);
- }
-
- // Verify that the catch clause are ordered in the right way:
- // more specialized first.
- this.caughtExceptionTypes = new ReferenceBinding[length];
- for (int i = 0; i < length; i++) {
- caughtExceptionTypes[i] = (ReferenceBinding) argumentTypes[i];
- for (int j = 0; j < i; j++) {
- if (caughtExceptionTypes[i].isCompatibleWith(argumentTypes[j])) {
- scope.problemReporter().wrongSequenceOfExceptionTypesError(this, caughtExceptionTypes[i], i, argumentTypes[j]);
- }
- }
- }
- } else {
- caughtExceptionTypes = new ReferenceBinding[0];
- }
-
- if (finallyScope != null){
- // add finallyScope as last subscope, so it can be shifted behind try/catch subscopes.
- // the shifting is necessary to achieve no overlay in between the finally scope and its
- // sibling in term of local variable positions.
- this.scope.addSubscope(finallyScope);
- }
- }
-
- public void traverse(
- ASTVisitor visitor,
- BlockScope blockScope) {
-
- if (visitor.visit(this, blockScope)) {
- tryBlock.traverse(visitor, scope);
- if (catchArguments != null) {
- for (int i = 0, max = catchBlocks.length; i < max; i++) {
- catchArguments[i].traverse(visitor, scope);
- catchBlocks[i].traverse(visitor, scope);
- }
- }
- if (finallyBlock != null)
- finallyBlock.traverse(visitor, scope);
- }
- visitor.endVisit(this, blockScope);
- }
-}
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