Beispiel #1
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;
    }
  }
  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

    this.preTryInitStateIndex = currentScope.methodScope().recordInitializationStates(flowInfo);

    if (this.anyExceptionVariable != null) {
      this.anyExceptionVariable.useFlag = LocalVariableBinding.USED;
    }
    if (this.returnAddressVariable != null) { // TODO (philippe) if subroutine is escaping, unused
      this.returnAddressVariable.useFlag = LocalVariableBinding.USED;
    }
    if (this.subRoutineStartLabel == null) {
      // no finally block -- this is a simplified copy of the else part
      // process the try block in a context handling the local exceptions.
      ExceptionHandlingFlowContext handlingContext =
          new ExceptionHandlingFlowContext(
              flowContext,
              this,
              this.caughtExceptionTypes,
              null,
              this.scope,
              flowInfo.unconditionalInits());
      handlingContext.initsOnFinally = new NullInfoRegistry(flowInfo.unconditionalInits());
      // only try blocks initialize that member - may consider creating a
      // separate class if needed

      FlowInfo tryInfo;
      if (this.tryBlock.isEmptyBlock()) {
        tryInfo = flowInfo;
      } else {
        tryInfo = this.tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
        if ((tryInfo.tagBits & FlowInfo.UNREACHABLE) != 0) this.bits |= ASTNode.IsTryBlockExiting;
      }

      // check unreachable catch blocks
      handlingContext.complainIfUnusedExceptionHandlers(this.scope, this);

      // process the catch blocks - computing the minimal exit depth amongst try/catch
      if (this.catchArguments != null) {
        int catchCount;
        this.catchExits = new boolean[catchCount = this.catchBlocks.length];
        this.catchExitInitStateIndexes = new int[catchCount];
        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;
          if (this.caughtExceptionTypes[i].isUncheckedException(true)) {
            catchInfo =
                handlingContext.initsOnFinally.mitigateNullInfoOf(
                    flowInfo
                        .unconditionalCopy()
                        .addPotentialInitializationsFrom(
                            handlingContext.initsOnException(this.caughtExceptionTypes[i]))
                        .addPotentialInitializationsFrom(tryInfo)
                        .addPotentialInitializationsFrom(handlingContext.initsOnReturn));
          } else {
            FlowInfo initsOnException =
                handlingContext.initsOnException(this.caughtExceptionTypes[i]);
            catchInfo =
                flowInfo
                    .nullInfoLessUnconditionalCopy()
                    .addPotentialInitializationsFrom(initsOnException)
                    .addNullInfoFrom(
                        initsOnException) // null info only from here, this is the only way to enter
                                          // the catch block
                    .addPotentialInitializationsFrom(tryInfo.nullInfoLessUnconditionalCopy())
                    .addPotentialInitializationsFrom(
                        handlingContext.initsOnReturn.nullInfoLessUnconditionalCopy());
          }

          // catch var is always set
          LocalVariableBinding catchArg = this.catchArguments[i].binding;
          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 (this.tryBlock.statements == null) {
            catchInfo.setReachMode(FlowInfo.UNREACHABLE);
          }
          catchInfo = this.catchBlocks[i].analyseCode(currentScope, flowContext, catchInfo);
          this.catchExitInitStateIndexes[i] =
              currentScope.methodScope().recordInitializationStates(catchInfo);
          this.catchExits[i] = (catchInfo.tagBits & FlowInfo.UNREACHABLE) != 0;
          tryInfo = tryInfo.mergedWith(catchInfo.unconditionalInits());
        }
      }
      this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(tryInfo);

      // chain up null info registry
      if (flowContext.initsOnFinally != null) {
        flowContext.initsOnFinally.add(handlingContext.initsOnFinally);
      }

      return tryInfo;
    } else {
      InsideSubRoutineFlowContext insideSubContext;
      FinallyFlowContext finallyContext;
      UnconditionalFlowInfo subInfo;
      // analyse finally block first
      insideSubContext = new InsideSubRoutineFlowContext(flowContext, this);

      subInfo =
          this.finallyBlock
              .analyseCode(
                  currentScope,
                  finallyContext = new FinallyFlowContext(flowContext, this.finallyBlock),
                  flowInfo.nullInfoLessUnconditionalCopy())
              .unconditionalInits();
      if (subInfo == FlowInfo.DEAD_END) {
        this.bits |= ASTNode.IsSubRoutineEscaping;
        this.scope.problemReporter().finallyMustCompleteNormally(this.finallyBlock);
      }
      this.subRoutineInits = subInfo;
      // process the try block in a context handling the local exceptions.
      ExceptionHandlingFlowContext handlingContext =
          new ExceptionHandlingFlowContext(
              insideSubContext,
              this,
              this.caughtExceptionTypes,
              null,
              this.scope,
              flowInfo.unconditionalInits());
      handlingContext.initsOnFinally = new NullInfoRegistry(flowInfo.unconditionalInits());
      // only try blocks initialize that member - may consider creating a
      // separate class if needed

      FlowInfo tryInfo;
      if (this.tryBlock.isEmptyBlock()) {
        tryInfo = flowInfo;
      } else {
        tryInfo = this.tryBlock.analyseCode(currentScope, handlingContext, flowInfo.copy());
        if ((tryInfo.tagBits & FlowInfo.UNREACHABLE) != 0) this.bits |= ASTNode.IsTryBlockExiting;
      }

      // check unreachable catch blocks
      handlingContext.complainIfUnusedExceptionHandlers(this.scope, this);

      // process the catch blocks - computing the minimal exit depth amongst try/catch
      if (this.catchArguments != null) {
        int catchCount;
        this.catchExits = new boolean[catchCount = this.catchBlocks.length];
        this.catchExitInitStateIndexes = new int[catchCount];
        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;
          if (this.caughtExceptionTypes[i].isUncheckedException(true)) {
            catchInfo =
                handlingContext.initsOnFinally.mitigateNullInfoOf(
                    flowInfo
                        .unconditionalCopy()
                        .addPotentialInitializationsFrom(
                            handlingContext.initsOnException(this.caughtExceptionTypes[i]))
                        .addPotentialInitializationsFrom(tryInfo)
                        .addPotentialInitializationsFrom(handlingContext.initsOnReturn));
          } else {
            FlowInfo initsOnException =
                handlingContext.initsOnException(this.caughtExceptionTypes[i]);
            catchInfo =
                flowInfo
                    .nullInfoLessUnconditionalCopy()
                    .addPotentialInitializationsFrom(initsOnException)
                    .addNullInfoFrom(
                        initsOnException) // null info only from here, this is the only way to enter
                                          // the catch block
                    .addPotentialInitializationsFrom(tryInfo.nullInfoLessUnconditionalCopy())
                    .addPotentialInitializationsFrom(
                        handlingContext.initsOnReturn.nullInfoLessUnconditionalCopy());
          }

          // catch var is always set
          LocalVariableBinding catchArg = this.catchArguments[i].binding;
          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 (this.tryBlock.statements == null) {
            catchInfo.setReachMode(FlowInfo.UNREACHABLE);
          }
          catchInfo = this.catchBlocks[i].analyseCode(currentScope, insideSubContext, catchInfo);
          this.catchExitInitStateIndexes[i] =
              currentScope.methodScope().recordInitializationStates(catchInfo);
          this.catchExits[i] = (catchInfo.tagBits & FlowInfo.UNREACHABLE) != 0;
          tryInfo = tryInfo.mergedWith(catchInfo.unconditionalInits());
        }
      }
      // 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(
          handlingContext.initsOnFinally.mitigateNullInfoOf(
              (tryInfo.tagBits & FlowInfo.UNREACHABLE) == 0
                  ? flowInfo
                      .unconditionalCopy()
                      .addPotentialInitializationsFrom(tryInfo)
                      .
                      // lighten the influence of the try block, which may have
                      // exited at any point
                      addPotentialInitializationsFrom(insideSubContext.initsOnReturn)
                  : insideSubContext.initsOnReturn),
          currentScope);

      // chain up null info registry
      if (flowContext.initsOnFinally != null) {
        flowContext.initsOnFinally.add(handlingContext.initsOnFinally);
      }

      this.naturalExitMergeInitStateIndex =
          currentScope.methodScope().recordInitializationStates(tryInfo);
      if (subInfo == FlowInfo.DEAD_END) {
        this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(subInfo);
        return subInfo;
      } else {
        FlowInfo mergedInfo = tryInfo.addInitializationsFrom(subInfo);
        this.mergedInitStateIndex =
            currentScope.methodScope().recordInitializationStates(mergedInfo);
        return mergedInfo;
      }
    }
  }