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Silence a use-after-free warning from the analyzer 

The analyzer is known to be very conservative in the face of atomic
operations (e.g. https://bugs.llvm.org/show_bug.cgi?id=34365); this case
is no different.

It's concerned that `delete this;` might read a different value for
`flags`, and proceed to delete `refs`. Since there are many comments
explaining why this won't happen (and it all looks sane to me), use a
NOLINT to silence this warning.

Analyzer warning:
system/core/libutils/RefBase.cpp:445:5: warning: Use of memory after it
is freed

Bug: 27101951
Test: mma. Use-after-free warning is gone.
Change-Id: Ic1623971bd1bad546fbb12a79439116c89a6762d
This commit is contained in:
George Burgess IV 2017-10-01 12:38:44 -07:00
parent 8b7feee38f
commit 6753bc4433
1 changed files with 5 additions and 0 deletions
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5
libutils/RefBase.cpp
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@ -442,6 +442,11 @@ void RefBase::decStrong(const void* id) const
// and all accesses to refs happen before its deletion in the final decWeak.
// The destructor can safely access mRefs because either it's deleting
// mRefs itself, or it's running entirely before the final mWeak decrement.
//
// Since we're doing atomic loads of `flags`, the static analyzer assumes
// they can change between `delete this;` and `refs->decWeak(id);`. This is
// not the case. The analyzer may become more okay with this patten when
// https://bugs.llvm.org/show_bug.cgi?id=34365 gets resolved. NOLINTNEXTLINE
refs->decWeak(id);
}