--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Common Public License v0.5
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v05.html
+ *
+ * Contributors:
+ * IBM Corporation - initial API and implementation
+ ******************************************************************************/
+package net.sourceforge.phpdt.internal.compiler.ast;
+
+import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
+import net.sourceforge.phpdt.internal.compiler.codegen.*;
+import net.sourceforge.phpdt.internal.compiler.flow.*;
+import net.sourceforge.phpdt.internal.compiler.lookup.*;
+
+public class TryStatement extends Statement {
+
+ public Block tryBlock;
+ public Block[] catchBlocks;
+ public Argument[] catchArguments;
+ public Block finallyBlock;
+ BlockScope scope;
+
+ public boolean subRoutineCannotReturn = true;
+ // 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.used = true;
+ }
+ if (returnAddressVariable != null) {
+ returnAddressVariable.used = true;
+ }
+ 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.DeadEnd) || subInfo.isFakeReachable())) {
+ subRoutineCannotReturn = false;
+ }
+ }
+ // 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.statements == null) {
+ tryInfo = flowInfo;
+ tryBlockExit = false;
+ } else {
+ tryInfo = tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
+ tryBlockExit = (tryInfo == FlowInfo.DeadEnd) || tryInfo.isFakeReachable();
+ }
+
+ // check unreachable catch blocks
+ handlingContext.complainIfUnusedExceptionHandlers(catchBlocks, 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]."
+ */
+ if (tryBlock.statements == null) {
+ catchInfo.markAsFakeReachable(true);
+ }
+ catchInfo =
+ catchBlocks[i].analyseCode(
+ currentScope,
+ insideSubContext == null ? flowContext : insideSubContext,
+ catchInfo);
+ catchExits[i] =
+ ((catchInfo == FlowInfo.DeadEnd) || catchInfo.isFakeReachable());
+ 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
+ tryInfo.addPotentialInitializationsFrom(insideSubContext.initsOnReturn);
+ finallyContext.complainOnRedundantFinalAssignments(tryInfo, currentScope);
+ if (subInfo == FlowInfo.DeadEnd) {
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(subInfo);
+ return subInfo;
+ } else {
+ FlowInfo mergedInfo = tryInfo.addInitializationsFrom(subInfo);
+ mergedInitStateIndex =
+ currentScope.methodScope().recordInitializationStates(mergedInfo);
+ return mergedInfo;
+ }
+ }
+
+ public boolean cannotReturn() {
+
+ return subRoutineCannotReturn;
+ }
+
+ /**
+ * Try statement code generation
+ *
+ */
+ public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+
+ if ((bits & IsReachableMASK) == 0) {
+ return;
+ }
+ if (tryBlock.isEmptyBlock()) {
+ if (subRoutineStartLabel != null) {
+ // since not passing the finallyScope, the block generation will exitUserScope(finallyScope)
+ finallyBlock.generateCode(scope, codeStream);
+ }
+ // May loose some local variable initializations : affecting the local variable attributes
+ if (mergedInitStateIndex != -1) {
+ codeStream.removeNotDefinitelyAssignedVariables(
+ currentScope,
+ mergedInitStateIndex);
+ }
+ // no local bytecode produced so no need for position remembering
+ return;
+ }
+ int pc = codeStream.position;
+ Label endLabel = new Label(codeStream);
+ boolean requiresNaturalJsr = false;
+
+ // preparing exception labels
+ int maxCatches;
+ ExceptionLabel[] exceptionLabels =
+ new ExceptionLabel[maxCatches =
+ catchArguments == null ? 0 : catchArguments.length];
+ for (int i = 0; i < maxCatches; i++) {
+ boolean preserveCurrentHandler =
+ (preserveExceptionHandler[i
+ / ExceptionHandlingFlowContext.BitCacheSize]
+ & (1 << (i % ExceptionHandlingFlowContext.BitCacheSize)))
+ != 0;
+ if (preserveCurrentHandler) {
+ exceptionLabels[i] =
+ new ExceptionLabel(
+ codeStream,
+ (ReferenceBinding) catchArguments[i].binding.type);
+ }
+ }
+ ExceptionLabel anyExceptionLabel = null;
+ if (subRoutineStartLabel != null) {
+ subRoutineStartLabel.codeStream = codeStream;
+ anyExceptionLabel = new ExceptionLabel(codeStream, null);
+ }
+ // generate the try block
+ tryBlock.generateCode(scope, codeStream);
+ boolean tryBlockHasSomeCode = codeStream.position != pc;
+ // flag telling if some bytecodes were issued inside the try block
+
+ // natural exit: only if necessary
+ boolean nonReturningSubRoutine =
+ (subRoutineStartLabel != null) && subRoutineCannotReturn;
+ if ((!tryBlockExit) && tryBlockHasSomeCode) {
+ int position = codeStream.position;
+ if (nonReturningSubRoutine) {
+ codeStream.goto_(subRoutineStartLabel);
+ } else {
+ requiresNaturalJsr = true;
+ codeStream.goto_(endLabel);
+ }
+ codeStream.updateLastRecordedEndPC(position);
+ //goto is tagged as part of the try block
+ }
+ // place end positions of user-defined exception labels
+ if (tryBlockHasSomeCode) {
+ for (int i = 0; i < maxCatches; i++) {
+ boolean preserveCurrentHandler =
+ (preserveExceptionHandler[i
+ / ExceptionHandlingFlowContext.BitCacheSize]
+ & (1 << (i % ExceptionHandlingFlowContext.BitCacheSize)))
+ != 0;
+ if (preserveCurrentHandler) {
+ 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) {
+ if (anyExceptionLabel != null) {
+ anyExceptionLabel.placeEnd();
+ }
+ } else {
+ for (int i = 0; i < maxCatches; i++) {
+ boolean preserveCurrentHandler =
+ (preserveExceptionHandler[i
+ / ExceptionHandlingFlowContext.BitCacheSize]
+ & (1 << (i % ExceptionHandlingFlowContext.BitCacheSize)))
+ != 0;
+ if (preserveCurrentHandler) {
+ // 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) {
+ if (anyExceptionLabel != null) {
+ anyExceptionLabel.placeEnd();
+ }
+ if (subRoutineStartLabel != null) {
+ if (!catchExits[i] && preserveCurrentHandler) {
+ requiresNaturalJsr = true;
+ codeStream.goto_(endLabel);
+ }
+ }
+ } else {
+ if (!catchExits[i] && preserveCurrentHandler) {
+ if (nonReturningSubRoutine) {
+ codeStream.goto_(subRoutineStartLabel);
+ } else {
+ requiresNaturalJsr = true;
+ codeStream.goto_(endLabel);
+ }
+ }
+ }
+ }
+ }
+ // 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
+ anyExceptionLabel.place();
+
+ if (preTryInitStateIndex != -1) {
+ // reset initialization state, as for a normal catch block
+ codeStream.removeNotDefinitelyAssignedVariables(
+ currentScope,
+ preTryInitStateIndex);
+ }
+
+ codeStream.incrStackSize(1);
+ if (nonReturningSubRoutine) {
+ codeStream.pop();
+ // "if subroutine cannot return, no need to jsr/jump to subroutine since it will be entered in sequence
+ } else {
+ codeStream.store(anyExceptionVariable, false);
+ codeStream.jsr(subRoutineStartLabel);
+ codeStream.load(anyExceptionVariable);
+ codeStream.athrow();
+ }
+ }
+ // end of catch sequence, place label that will correspond to the finally block beginning, or end of statement
+ endLabel.place();
+ if (subRoutineStartLabel != null) {
+ if (nonReturningSubRoutine) {
+ requiresNaturalJsr = false;
+ }
+ Label veryEndLabel = new Label(codeStream);
+ if (requiresNaturalJsr) {
+ codeStream.jsr(subRoutineStartLabel);
+ codeStream.goto_(veryEndLabel);
+ }
+ subRoutineStartLabel.place();
+ if (!nonReturningSubRoutine) {
+ codeStream.incrStackSize(1);
+ codeStream.store(returnAddressVariable, false);
+ }
+ codeStream.recordPositionsFrom(
+ finallySequenceStartPC,
+ finallyBlock.sourceStart);
+ // entire sequence for finally is associated to finally block
+ finallyBlock.generateCode(scope, codeStream);
+ if (!nonReturningSubRoutine) {
+ int position = codeStream.position;
+ codeStream.ret(returnAddressVariable.resolvedPosition);
+ codeStream.updateLastRecordedEndPC(position);
+ // the ret bytecode is part of the subroutine
+ }
+ if (requiresNaturalJsr) {
+ veryEndLabel.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);
+ }
+
+ 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
+ && finallyBlock.statements != null) {
+
+ 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 its not a normal base type
+ 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 (scope.areTypesCompatible(caughtExceptionTypes[i], argumentTypes[j])) {
+ scope.problemReporter().wrongSequenceOfExceptionTypesError(this, i, j);
+ return;
+ }
+ }
+ }
+ } 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 String toString(int tab) {
+ String s = tabString(tab);
+ //try
+ s = s + "try "; //$NON-NLS-1$
+ if (tryBlock == Block.None)
+ s = s + "{}"; //$NON-NLS-1$
+ else
+ s = s + "\n" + tryBlock.toString(tab + 1); //$NON-NLS-1$
+
+ //catches
+ if (catchBlocks != null)
+ for (int i = 0; i < catchBlocks.length; i++)
+ s = s + "\n" + tabString(tab) + "catch (" //$NON-NLS-2$ //$NON-NLS-1$
+ +catchArguments[i].toString(0) + ") " //$NON-NLS-1$
+ +catchBlocks[i].toString(tab + 1);
+ //finally
+ if (finallyBlock != null) {
+ if (finallyBlock == Block.None)
+ s = s + "\n" + tabString(tab) + "finally {}"; //$NON-NLS-2$ //$NON-NLS-1$
+ else
+ s = s + "\n" + tabString(tab) + "finally\n" + //$NON-NLS-2$ //$NON-NLS-1$
+ finallyBlock.toString(tab + 1);
+ }
+
+ return s;
+ }
+
+ public void traverse(
+ IAbstractSyntaxTreeVisitor 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);
+ }
+}
\ No newline at end of file
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