public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
this.breakLabel = new BranchLabel();
this.continueLabel = new BranchLabel();
LoopingFlowContext loopingContext =
new LoopingFlowContext(
flowContext, flowInfo, this, this.breakLabel, this.continueLabel, currentScope);
Constant cst = this.condition.constant;
boolean isConditionTrue = cst != Constant.NotAConstant && cst.booleanValue() == true;
cst = this.condition.optimizedBooleanConstant();
boolean isConditionOptimizedTrue = cst != Constant.NotAConstant && cst.booleanValue() == true;
boolean isConditionOptimizedFalse = cst != Constant.NotAConstant && cst.booleanValue() == false;
int previousMode = flowInfo.reachMode();
UnconditionalFlowInfo actionInfo = flowInfo.nullInfoLessUnconditionalCopy();
// we need to collect the contribution to nulls of the coming paths through the
// loop, be they falling through normally or branched to break, continue labels
// or catch blocks
if ((this.action != null) && !this.action.isEmptyBlock()) {
actionInfo =
this.action.analyseCode(currentScope, loopingContext, actionInfo).unconditionalInits();
// code generation can be optimized when no need to continue in the loop
if ((actionInfo.tagBits & loopingContext.initsOnContinue.tagBits & FlowInfo.UNREACHABLE)
!= 0) {
this.continueLabel = null;
}
}
/* Reset reach mode, to address following scenario.
* final blank;
* do { if (true) break; else blank = 0; } while(false);
* blank = 1; // may be initialized already
*/
actionInfo.setReachMode(previousMode);
LoopingFlowContext condLoopContext;
FlowInfo condInfo =
this.condition.analyseCode(
currentScope,
(condLoopContext =
new LoopingFlowContext(flowContext, flowInfo, this, null, null, currentScope)),
(this.action == null
? actionInfo
: (actionInfo.mergedWith(loopingContext.initsOnContinue)))
.copy());
this.preConditionInitStateIndex =
currentScope.methodScope().recordInitializationStates(actionInfo);
if (!isConditionOptimizedFalse && this.continueLabel != null) {
loopingContext.complainOnDeferredFinalChecks(currentScope, condInfo);
condLoopContext.complainOnDeferredFinalChecks(currentScope, condInfo);
loopingContext.complainOnDeferredNullChecks(
currentScope,
flowInfo
.unconditionalCopy()
.addPotentialNullInfoFrom(condInfo.initsWhenTrue().unconditionalInits()));
condLoopContext.complainOnDeferredNullChecks(
currentScope,
actionInfo.addPotentialNullInfoFrom(condInfo.initsWhenTrue().unconditionalInits()));
}
// end of loop
FlowInfo mergedInfo =
FlowInfo.mergedOptimizedBranches(
(loopingContext.initsOnBreak.tagBits & FlowInfo.UNREACHABLE) != 0
? loopingContext.initsOnBreak
: flowInfo.unconditionalCopy().addInitializationsFrom(loopingContext.initsOnBreak),
// recover upstream null info
isConditionOptimizedTrue,
(condInfo.tagBits & FlowInfo.UNREACHABLE) == 0
? flowInfo.addInitializationsFrom(condInfo.initsWhenFalse())
: condInfo,
// recover null inits from before condition analysis
false, // never consider opt false case for DO loop, since break can always occur
// (47776)
!isConditionTrue /*do{}while(true); unreachable(); */);
this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);
return mergedInfo;
}
