Merge pull request #2003 from alexanderkjeldaas/documented-locking-part-2

Documented locking part 1+2
This commit is contained in:
Gavin Andresen 2012-12-12 09:27:35 -08:00
commit 8a7277a578
3 changed files with 82 additions and 18 deletions

View File

@ -305,7 +305,8 @@ public:
void BeginMessage(const char* pszCommand) // TODO: Document the postcondition of this function. Is cs_vSend locked?
void BeginMessage(const char* pszCommand) EXCLUSIVE_LOCK_FUNCTION(cs_vSend)
{ {
ENTER_CRITICAL_SECTION(cs_vSend); ENTER_CRITICAL_SECTION(cs_vSend);
if (nHeaderStart != -1) if (nHeaderStart != -1)
@ -317,7 +318,8 @@ public:
printf("sending: %s ", pszCommand); printf("sending: %s ", pszCommand);
} }
void AbortMessage() // TODO: Document the precondition of this function. Is cs_vSend locked?
void AbortMessage() UNLOCK_FUNCTION(cs_vSend)
{ {
if (nHeaderStart < 0) if (nHeaderStart < 0)
return; return;
@ -330,7 +332,8 @@ public:
printf("(aborted)\n"); printf("(aborted)\n");
} }
void EndMessage() // TODO: Document the precondition of this function. Is cs_vSend locked?
void EndMessage() UNLOCK_FUNCTION(cs_vSend)
{ {
if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0) if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
{ {
@ -362,19 +365,6 @@ public:
LEAVE_CRITICAL_SECTION(cs_vSend); LEAVE_CRITICAL_SECTION(cs_vSend);
} }
void EndMessageAbortIfEmpty()
{
if (nHeaderStart < 0)
return;
int nSize = vSend.size() - nMessageStart;
if (nSize > 0)
EndMessage();
else
AbortMessage();
}
void PushVersion(); void PushVersion();

View File

@ -9,15 +9,36 @@
#include <boost/thread/recursive_mutex.hpp> #include <boost/thread/recursive_mutex.hpp>
#include <boost/thread/locks.hpp> #include <boost/thread/locks.hpp>
#include <boost/thread/condition_variable.hpp> #include <boost/thread/condition_variable.hpp>
#include "threadsafety.h"
// Template mixin that adds -Wthread-safety locking annotations to a
// subset of the mutex API.
template <typename PARENT>
class LOCKABLE AnnotatedMixin : public PARENT
{
public:
void lock() EXCLUSIVE_LOCK_FUNCTION()
{
PARENT::lock();
}
void unlock() UNLOCK_FUNCTION()
{
PARENT::unlock();
}
bool try_lock() EXCLUSIVE_TRYLOCK_FUNCTION(true)
{
return PARENT::try_lock();
}
};
/** Wrapped boost mutex: supports recursive locking, but no waiting */ /** Wrapped boost mutex: supports recursive locking, but no waiting */
typedef boost::recursive_mutex CCriticalSection; // TODO: We should move away from using the recursive lock by default.
typedef AnnotatedMixin<boost::recursive_mutex> CCriticalSection;
/** Wrapped boost mutex: supports waiting but not recursive locking */ /** Wrapped boost mutex: supports waiting but not recursive locking */
typedef boost::mutex CWaitableCriticalSection; typedef AnnotatedMixin<boost::mutex> CWaitableCriticalSection;
#ifdef DEBUG_LOCKORDER #ifdef DEBUG_LOCKORDER
void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false); void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false);

53
src/threadsafety.h Normal file
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@ -0,0 +1,53 @@
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_THREADSAFETY_H
#define BITCOIN_THREADSAFETY_H
#ifdef __clang__
// TL;DR Add GUARDED_BY(mutex) to member variables. The others are
// rarely necessary. Ex: int nFoo GUARDED_BY(cs_foo);
//
// See http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety
// for documentation. The clang compiler can do advanced static analysis
// of locking when given the -Wthread-safety option.
#define LOCKABLE __attribute__ ((lockable))
#define SCOPED_LOCKABLE __attribute__ ((scoped_lockable))
#define GUARDED_BY(x) __attribute__ ((guarded_by(x)))
#define GUARDED_VAR __attribute__ ((guarded_var))
#define PT_GUARDED_BY(x) __attribute__ ((pt_guarded_by(x)))
#define PT_GUARDED_VAR __attribute__ ((pt_guarded_var))
#define ACQUIRED_AFTER(...) __attribute__ ((acquired_after(__VA_ARGS__)))
#define ACQUIRED_BEFORE(...) __attribute__ ((acquired_before(__VA_ARGS__)))
#define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__ ((exclusive_lock_function(__VA_ARGS__)))
#define SHARED_LOCK_FUNCTION(...) __attribute__ ((shared_lock_function(__VA_ARGS__)))
#define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__ ((exclusive_trylock_function(__VA_ARGS__)))
#define SHARED_TRYLOCK_FUNCTION(...) __attribute__ ((shared_trylock_function(__VA_ARGS__)))
#define UNLOCK_FUNCTION(...) __attribute__ ((unlock_function(__VA_ARGS__)))
#define LOCK_RETURNED(x) __attribute__ ((lock_returned(x)))
#define LOCKS_EXCLUDED(...) __attribute__ ((locks_excluded(__VA_ARGS__)))
#define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__ ((exclusive_locks_required(__VA_ARGS__)))
#define SHARED_LOCKS_REQUIRED(...) __attribute__ ((shared_locks_required(__VA_ARGS__)))
#define NO_THREAD_SAFETY_ANALYSIS __attribute__ ((no_thread_safety_analysis))
#else
#define LOCKABLE
#define SCOPED_LOCKABLE
#define GUARDED_BY(x)
#define GUARDED_VAR
#define PT_GUARDED_BY(x)
#define PT_GUARDED_VAR
#define ACQUIRED_AFTER(...)
#define ACQUIRED_BEFORE(...)
#define EXCLUSIVE_LOCK_FUNCTION(...)
#define SHARED_LOCK_FUNCTION(...)
#define EXCLUSIVE_TRYLOCK_FUNCTION(...)
#define SHARED_TRYLOCK_FUNCTION(...)
#define UNLOCK_FUNCTION(...)
#define LOCK_RETURNED(x)
#define LOCKS_EXCLUDED(...)
#define EXCLUSIVE_LOCKS_REQUIRED(...)
#define SHARED_LOCKS_REQUIRED(...)
#define NO_THREAD_SAFETY_ANALYSIS
#endif // __GNUC__
#endif // BITCOIN_THREADSAFETY_H