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DefiniteInitialization: fix a minor problem with memory lifetime

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Dead loads for type-of-self must be removed, otherwise it's a violation of memory lifetime.
This commit is contained in:
Erik Eckstein
2019-08-07 17:59:36 +02:00
parent 32c0feb577
commit 0bac147361
1 changed files with 13 additions and 2 deletions
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15
lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp
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@@ -457,7 +457,7 @@ namespace {
void handleStoreUse(unsigned UseID);
void handleLoadUse(const DIMemoryUse &Use);
void handleLoadForTypeOfSelfUse(const DIMemoryUse &Use);
void handleLoadForTypeOfSelfUse(DIMemoryUse &Use);
void handleInOutUse(const DIMemoryUse &Use);
void handleEscapeUse(const DIMemoryUse &Use);
@@ -829,7 +829,7 @@ void LifetimeChecker::handleLoadUse(const DIMemoryUse &Use) {
return handleLoadUseFailure(Use, IsSuperInitComplete, FailedSelfUse);
}
void LifetimeChecker::handleLoadForTypeOfSelfUse(const DIMemoryUse &Use) {
void LifetimeChecker::handleLoadForTypeOfSelfUse(DIMemoryUse &Use) {
bool IsSuperInitComplete, FailedSelfUse;
// If the value is not definitively initialized, replace the
// value_metatype instruction with the metatype argument that was passed into
@@ -869,6 +869,17 @@ void LifetimeChecker::handleLoadForTypeOfSelfUse(const DIMemoryUse &Use) {
valueMetatype->getType());
}
replaceAllSimplifiedUsesAndErase(valueMetatype, metatypeArgument);
// Dead loads for type-of-self must be removed.
// Otherwise it's a violation of memory lifetime.
if (isa<LoadBorrowInst>(load)) {
assert(load->hasOneUse() && isa<EndBorrowInst>(load->getSingleUse()->getUser()));
load->getSingleUse()->getUser()->eraseFromParent();
}
assert(load->use_empty());
load->eraseFromParent();
// Clear the Inst pointer just to be sure to avoid use-after-free.
Use.Inst = nullptr;
}
}