Fix lookupDirect() use-after-scope bugs #20557
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In swiftlang#7530, NominalTypeDecl::lookupDirect() started returning TinyPtrVector instead of ArrayRef so that it wouldn’t be returning a pointer into a mutable data structure. Unfortunately, some callees assigned its return value into an ArrayRef; C++ happily converted the TinyPtrVector to an ArrayRef and then treated the TinyPtrVector as out-of-scope, so the ArrayRef would now point to an out-of-scope object. Oops.
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@swift-ci please smoke test |
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@swift-ci please asan test |
jrose-apple
reviewed
Nov 14, 2018
| @@ -7048,7 +7048,7 @@ void SwiftDeclConverter::importInheritedConstructors( | |||
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| auto curObjCClass = cast<clang::ObjCInterfaceDecl>(classDecl->getClangDecl()); | |||
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| auto inheritConstructors = [&](ArrayRef<ValueDecl *> members, | |||
| auto inheritConstructors = [&](TinyPtrVector<ValueDecl *> members, | |||
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This one should be okay, no? Passing something down the stack should always be okay (because of C++'s "destruction happens at the end of the full-expression" rule.)
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ASan didn’t show any failures here—I just thought it looked suspicious and would be fairly cheap to recode defensively—so if that’s the rule, this one is probably unnecessary.
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Thank you! |
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Looks good! Merging to try to fix bots. |
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In #7530, NominalTypeDecl::lookupDirect() started returning TinyPtrVector instead of ArrayRef. Unfortunately, some callees assigned its return value to a variable explicitly declared to be an ArrayRef; C++ happily converted the TinyPtrVector to an ArrayRef and then treated the TinyPtrVector as out-of-scope, so the ArrayRef would now point to an out-of-scope stack object.
This PR should fix ASan stack-use-after-scope test failures whose backtraces include one of:
There may still be other ASan failures after this PR. There should not be any normal test failures.
Resolves rdar://46031343.