コード例 #1
0
  public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
    this.preAssertInitStateIndex = currentScope.methodScope().recordInitializationStates(flowInfo);

    Constant cst = this.assertExpression.optimizedBooleanConstant();
    if ((this.assertExpression.implicitConversion & TypeIds.UNBOXING) != 0) {
      this.assertExpression.checkNPE(currentScope, flowContext, flowInfo);
    }
    boolean isOptimizedTrueAssertion = cst != Constant.NotAConstant && cst.booleanValue() == true;
    boolean isOptimizedFalseAssertion = cst != Constant.NotAConstant && cst.booleanValue() == false;

    flowContext.tagBits |= FlowContext.HIDE_NULL_COMPARISON_WARNING;
    FlowInfo conditionFlowInfo =
        this.assertExpression.analyseCode(currentScope, flowContext, flowInfo.copy());
    flowContext.extendTimeToLiveForNullCheckedField(1); // survive this assert as a Statement
    flowContext.tagBits &= ~FlowContext.HIDE_NULL_COMPARISON_WARNING;
    UnconditionalFlowInfo assertWhenTrueInfo =
        conditionFlowInfo.initsWhenTrue().unconditionalInits();
    FlowInfo assertInfo = conditionFlowInfo.initsWhenFalse();
    if (isOptimizedTrueAssertion) {
      assertInfo.setReachMode(FlowInfo.UNREACHABLE_OR_DEAD);
    }

    if (this.exceptionArgument != null) {
      // only gets evaluated when escaping - results are not taken into account
      FlowInfo exceptionInfo =
          this.exceptionArgument.analyseCode(currentScope, flowContext, assertInfo.copy());

      if (isOptimizedTrueAssertion) {
        currentScope.problemReporter().fakeReachable(this.exceptionArgument);
      } else {
        flowContext.checkExceptionHandlers(
            currentScope.getJavaLangAssertionError(), this, exceptionInfo, currentScope);
      }
    }

    if (!isOptimizedTrueAssertion) {
      // add the assert support in the clinit
      manageSyntheticAccessIfNecessary(currentScope, flowInfo);
    }
    // account for potential AssertionError:
    flowContext.recordAbruptExit();
    if (isOptimizedFalseAssertion) {
      return flowInfo; // if assertions are enabled, the following code will be unreachable
      // change this if we need to carry null analysis results of the assert
      // expression downstream
    } else {
      CompilerOptions compilerOptions = currentScope.compilerOptions();
      if (!compilerOptions.includeNullInfoFromAsserts) {
        // keep just the initializations info, don't include assert's null info
        // merge initialization info's and then add back the null info from flowInfo to
        // make sure that the empty null info of assertInfo doesnt change flowInfo's null info.
        return ((flowInfo.nullInfoLessUnconditionalCopy())
                .mergedWith(assertInfo.nullInfoLessUnconditionalCopy()))
            .addNullInfoFrom(flowInfo);
      }
      return flowInfo
          .mergedWith(assertInfo.nullInfoLessUnconditionalCopy())
          .addInitializationsFrom(assertWhenTrueInfo.discardInitializationInfo());
      // keep the merge from the initial code for the definite assignment
      // analysis, tweak the null part to influence nulls downstream
    }
  }
コード例 #2
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

    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;
      }
    }
  }