The lockorder potential deadlock detection works by remembering for each
lock A that is acquired while holding another B the pair (A,B), and
triggering a warning when (B,A) already exists in the table.
A and B in the above text are represented by pointers to the CCriticalSection
object that is acquired. This does mean however that we need to clean up the
table entries that refer to any critical section which is destroyed, as it
memory address can potentially be used for another unrelated lock in the future.
Implement this clean up by remembering not only the pairs in forward direction,
but also backward direction. This allows for fast iteration over all pairs that
use a deleted CCriticalSection in either the first or the second position.
This allows us to use function/variable/class attributes to specify locking
requisites, allowing problems to be detected during static analysis.
This works perfectly with newer Clang versions (tested with 3.3-3.7). For older
versions (tested 3.2), it compiles fine but spews lots of false-positives.
Rebased by @laanwj:
- update for RPC methods added since 84d13ee: setmocktime,
invalidateblock, reconsiderblock. Only the first, setmocktime, required a change,
the other two are thread safe.
- ensures a consistent usage in header files
- also add a blank line after the copyright header where missing
- also remove orphan new-lines at the end of some files
Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.
o Remove unused Leave and GetLock functions
o Make Enter and TryEnter private.
o Simplify Enter and TryEnter.
boost::unique_lock doesn't really know whether the
mutex it wraps is locked or not when the defer_lock
option is used.
The boost::recursive_mutex does not expose this
information, so unique_lock only infers this
knowledge. When taking the lock is defered, it
(randomly) assumes that the lock is not taken.
boost::unique_lock has the following definition:
unique_lock(Mutex& m_,defer_lock_t):
m(&m_),is_locked(false)
{}
bool owns_lock() const
{
return is_locked;
}
Thus it is a mistake to check owns_lock() in Enter
and TryEnter - they will always return false.
Pieter Wuille