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Java: Fixed false positive "unreachable statement" in the control flow analysis (IDEA-164442)

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This commit is contained in:
Pavel Dolgov
2016-11-30 13:04:34 +03:00
parent 09b3348d68
commit 2f5e954770
2 changed files with 69 additions and 28 deletions
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java/java-psi-impl/src/com/intellij/psi/controlFlow/ControlFlowAnalyzer.java
+54 -28
View File
@@ -44,7 +44,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
private final Stack<PsiParameter> myCatchParameters = new Stack<PsiParameter>();// stack of PsiParameter for catch
private final Stack<PsiElement> myCatchBlocks = new Stack<PsiElement>();
private final Stack<PsiElement> myFinallyBlocks = new Stack<PsiElement>();
private final Stack<FinallyBlockSubroutine> myFinallyBlocks = new Stack<FinallyBlockSubroutine>();
private final Stack<PsiElement> myUnhandledExceptionCatchBlocks = new Stack<PsiElement>();
// element to jump to from inner (sub)expression in "jump to begin" situation.
@@ -271,7 +271,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
// generate jump to the top finally block
if (!myFinallyBlocks.isEmpty()) {
final PsiElement finallyBlock = myFinallyBlocks.peek();
final PsiElement finallyBlock = myFinallyBlocks.peek().getElement();
ConditionalThrowToInstruction throwToInstruction = new ConditionalThrowToInstruction(-2);
myCurrentFlow.addInstruction(throwToInstruction);
if (!patchUncheckedThrowInstructionIfInsideFinally(throwToInstruction, element, finallyBlock)) {
@@ -431,13 +431,16 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
}
private void callFinallyBlocksOnExit(PsiStatement exitedStatement) {
for (final ListIterator<PsiElement> it = myFinallyBlocks.listIterator(myFinallyBlocks.size()); it.hasPrevious(); ) {
final PsiElement finallyBlock = it.previous();
for (final ListIterator<FinallyBlockSubroutine> it = myFinallyBlocks.listIterator(myFinallyBlocks.size()); it.hasPrevious(); ) {
final FinallyBlockSubroutine finallyBlockSubroutine = it.previous();
PsiElement finallyBlock = finallyBlockSubroutine.getElement();
final PsiElement enclosingTryStatement = finallyBlock.getParent();
if (enclosingTryStatement == null || !PsiTreeUtil.isAncestor(exitedStatement, enclosingTryStatement, false)) {
break;
}
myCurrentFlow.addInstruction(new CallInstruction(0, 0, myStack));
CallInstruction instruction = new CallInstruction(0, 0, myStack);
finallyBlockSubroutine.addCall(instruction);
myCurrentFlow.addInstruction(instruction);
addElementOffsetLater(finallyBlock, true);
}
}
@@ -842,7 +845,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
}
else {
instruction.offset = -4; // -4 for return
addElementOffsetLater(myFinallyBlocks.peek(), true);
addElementOffsetLater(myFinallyBlocks.peek().getElement(), true);
}
}
}
@@ -935,7 +938,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
}
else {
instruction.offset = -2; // -2 to rethrow exception
element = myFinallyBlocks.peek();
element = myFinallyBlocks.peek().getElement();
addElementOffsetLater(element, true);
}
}
@@ -1069,8 +1072,10 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
PsiCodeBlock finallyBlock = statement.getFinallyBlock();
FinallyBlockSubroutine finallyBlockSubroutine = null;
if (finallyBlock != null) {
myFinallyBlocks.push(finallyBlock);
finallyBlockSubroutine = new FinallyBlockSubroutine(finallyBlock);
myFinallyBlocks.push(finallyBlockSubroutine);
}
PsiResourceList resourceList = statement.getResourceList();
@@ -1129,16 +1134,22 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
if (finallyBlock != null) {
// normal completion, call finally block and proceed
myCurrentFlow.addInstruction(new CallInstruction(0, 0, myStack));
CallInstruction normalCompletion = new CallInstruction(0, 0, myStack);
finallyBlockSubroutine.addCall(normalCompletion);
myCurrentFlow.addInstruction(normalCompletion);
addElementOffsetLater(finallyBlock, true);
myCurrentFlow.addInstruction(new GoToInstruction(0));
addElementOffsetLater(statement, false);
// return completion, call finally block and return
myCurrentFlow.addInstruction(new CallInstruction(0, 0, myStack));
CallInstruction returnCompletion = new CallInstruction(0, 0, myStack);
finallyBlockSubroutine.addCall(returnCompletion);
myCurrentFlow.addInstruction(returnCompletion);
addElementOffsetLater(finallyBlock, true);
addReturnInstruction(statement);
// throw exception completion, call finally block and rethrow
myCurrentFlow.addInstruction(new CallInstruction(0, 0, myStack));
CallInstruction throwExceptionCompletion = new CallInstruction(0, 0, myStack);
finallyBlockSubroutine.addCall(throwExceptionCompletion);
myCurrentFlow.addInstruction(throwExceptionCompletion);
addElementOffsetLater(finallyBlock, true);
final GoToInstruction gotoUncheckedRethrow = new GoToInstruction(0);
myCurrentFlow.addInstruction(gotoUncheckedRethrow);
@@ -1147,31 +1158,22 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
finallyBlock.accept(this);
final int procStart = myCurrentFlow.getStartOffset(finallyBlock);
final int procEnd = myCurrentFlow.getEndOffset(finallyBlock);
int offset = procStart - 6;
final List<Instruction> instructions = myCurrentFlow.getInstructions();
CallInstruction callInstruction = (CallInstruction)instructions.get(offset);
callInstruction.procBegin = procStart;
callInstruction.procEnd = procEnd;
offset += 2;
callInstruction = (CallInstruction)instructions.get(offset);
callInstruction.procBegin = procStart;
callInstruction.procEnd = procEnd;
offset += 2;
callInstruction = (CallInstruction)instructions.get(offset);
callInstruction.procBegin = procStart;
callInstruction.procEnd = procEnd;
for (CallInstruction callInstruction : finallyBlockSubroutine.getCalls()) {
callInstruction.procBegin = procStart;
callInstruction.procEnd = procEnd;
}
// generate return instructions
// first three return instructions are for normal completion, return statement call completion and unchecked exception throwing completion resp.
// normal completion
myCurrentFlow.addInstruction(new ReturnInstruction(0, myStack, callInstruction));
myCurrentFlow.addInstruction(new ReturnInstruction(0, myStack, normalCompletion));
// return statement call completion
myCurrentFlow.addInstruction(new ReturnInstruction(procStart - 3, myStack, callInstruction));
myCurrentFlow.addInstruction(new ReturnInstruction(procStart - 3, myStack, returnCompletion));
// unchecked exception throwing completion
myCurrentFlow.addInstruction(new ReturnInstruction(procStart - 1, myStack, callInstruction));
myCurrentFlow.addInstruction(new ReturnInstruction(procStart - 1, myStack, throwExceptionCompletion));
// checked exception throwing completion. need to dispatch to the correct catch clause
final List<PsiElement> unhandledExceptionCatchBlocks = finallyBlockToUnhandledExceptions.remove(finallyBlock);
@@ -1179,7 +1181,7 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
ProgressManager.checkCanceled();
PsiElement catchBlock = unhandledExceptionCatchBlocks.get(i);
final ReturnInstruction returnInstruction = new ReturnInstruction(0, myStack, callInstruction);
final ReturnInstruction returnInstruction = new ReturnInstruction(0, myStack, throwExceptionCompletion);
returnInstruction.setRethrowFromFinally();
myCurrentFlow.addInstruction(returnInstruction);
if (catchBlock == null) {
@@ -1725,4 +1727,28 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
if (refExpr.getParent() instanceof PsiMethodCallExpression) return null;
return myPolicy.getUsedVariable(refExpr);
}
private static class FinallyBlockSubroutine {
private final PsiElement myElement;
private final List<CallInstruction> myCalls;
public FinallyBlockSubroutine(@NotNull PsiElement element) {
myElement = element;
myCalls = new ArrayList<CallInstruction>();
}
@NotNull
public PsiElement getElement() {
return myElement;
}
@NotNull
public List<CallInstruction> getCalls() {
return myCalls;
}
private void addCall(@NotNull CallInstruction callInstruction) {
myCalls.add(callInstruction);
}
}
}
java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting/Unreachable.java
+15
View File
@@ -488,4 +488,19 @@ class ManyExitsFromTry {
}
}
}
}
class BreakFromCatchInPresenceOfFinally {
String f() {
while (true) {
try {
return "try";
}
catch (Exception e) {
break;
}
finally {}
}
return "end"; // reachable
}
}