Example #1
0
  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);
  }
Example #2
0
  public StringBuffer printStatement(int indent, StringBuffer output) {
    printIndent(indent, output).append("try \n"); // $NON-NLS-1$
    tryBlock.printStatement(indent + 1, output);

    // 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;
  }
Example #3
0
  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().discardNullRelatedInitializations())
              .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
        LocalVariableBinding catchArg = catchArguments[i].binding;
        FlowContext catchContext = insideSubContext == null ? flowContext : insideSubContext;
        catchInfo.markAsDefinitelyAssigned(catchArg);
        catchInfo.markAsDefinitelyNonNull(catchArg);
        /*
        "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.setReachMode(FlowInfo.UNREACHABLE);
        }
        catchInfo = catchBlocks[i].analyseCode(currentScope, catchContext, 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.complainOnDeferredChecks(
        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;
    }
  }
Example #4
0
  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.compilerOptions().inlineJsrBytecode) {
          this.returnAddressVariable =
              new LocalVariableBinding(
                  SecretReturnName, upperScope.getJavaLangObject(), AccDefault, false);
          finallyScope.addLocalVariable(returnAddressVariable);
          this.returnAddressVariable.setConstant(NotAConstant); // not inlinable
        }
        this.subRoutineStartLabel = new Label();

        this.anyExceptionVariable =
            new LocalVariableBinding(
                SecretAnyHandlerName, scope.getJavaLangThrowable(), AccDefault, false);
        finallyScope.addLocalVariable(this.anyExceptionVariable);
        this.anyExceptionVariable.setConstant(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.setConstant(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];
      boolean catchHasError = false;
      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) {
          catchHasError = true;
        }
        catchBlocks[i].resolveUsing(catchScope);
      }
      if (catchHasError) {
        return;
      }
      // 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);
    }
  }
Example #5
0
  /**
   * 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.compilerOptions().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(tryBlock.scope, 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) {
        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 (!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;
            }
          }
        }
      }
      this.exitAnyExceptionHandler();
      // extra handler for trailing natural exit (will be fixed up later on when natural exit is
      // generated below)
      ExceptionLabel naturalExitExceptionHandler =
          finallyMode == FINALLY_SUBROUTINE && requiresNaturalExit
              ? new ExceptionLabel(codeStream, null)
              : 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) {
        this.placeAllAnyExceptionHandlers();
        if (naturalExitExceptionHandler != null) naturalExitExceptionHandler.place();

        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.recordPositionsFrom(finallySequenceStartPC, finallyBlock.sourceStart);
            int position = codeStream.position;
            codeStream.load(anyExceptionVariable);
            codeStream.athrow();
            codeStream.recordPositionsFrom(position, finallyBlock.sourceEnd);
            subRoutineStartLabel.place();
            codeStream.incrStackSize(1);
            position = codeStream.position;
            codeStream.store(returnAddressVariable, false);
            codeStream.recordPositionsFrom(position, finallyBlock.sourceStart);
            finallyBlock.generateCode(scope, codeStream);
            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);
            codeStream.recordPositionsFrom(finallySequenceStartPC, finallyBlock.sourceStart);
            this.finallyBlock.generateCode(currentScope, codeStream);
            position = codeStream.position;
            codeStream.load(anyExceptionVariable);
            codeStream.athrow();
            subRoutineStartLabel.place();
            codeStream.recordPositionsFrom(position, finallyBlock.sourceEnd);
            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.sourceEnd);
              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);
  }