Author: rfm
Date: Tue Nov 8 11:21:00 2016
New Revision: 40196
URL: http://svn.gna.org/viewcvs/gnustep?rev=40196&view=rev
Log:
fix crash and other memory management tweaks
Modified:
libs/base/trunk/ChangeLog
libs/base/trunk/Source/NSObject.m
Modified: libs/base/trunk/ChangeLog
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/ChangeLog?rev=40196&r1=40195&r2=40196&view=diff
==============================================================================
--- libs/base/trunk/ChangeLog (original)
+++ libs/base/trunk/ChangeLog Tue Nov 8 11:21:00 2016
@@ -1,6 +1,13 @@
+2016-11-08 Richard Frith-Macdonald <r...@gnu.org>
+
+ * Source/NSObject.m: Fix error in last mod ... was calculating opbject
+ layout incorrectly when fast-ARC moce used on 64bit system.
+ Also simplified by removing special case optimising for single-threaded
+ programs and use inline decrement to improve performance of release.
+
2016-10-28 Niels Grewe <niels.gr...@halbordnung.de>
- * Source/NSObject.m: Re-enable fast-ARC mode when memory layout
+ * Source/NSObject.m: Re-enable fast-ARC mode when memory layout
and atomic operations support permit. This changes the size of the
field where the reference count is stored to the size of a pointer
in some configurations.
Modified: libs/base/trunk/Source/NSObject.m
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/Source/NSObject.m?rev=40196&r1=40195&r2=40196&view=diff
==============================================================================
--- libs/base/trunk/Source/NSObject.m (original)
+++ libs/base/trunk/Source/NSObject.m Tue Nov 8 11:21:00 2016
@@ -113,11 +113,10 @@
- (id) initWithObject: (id)anObject;
@end
-/*
- * allocationLock is needed when running multi-threaded for
- * protecting the map table of zombie information.
- */
-static NSLock *allocationLock;
+/* allocationLock is needed when for protecting the map table of zombie
+ * information and if atomic operations are not available.
+ */
+static NSLock *allocationLock = nil;
BOOL NSZombieEnabled = NO;
BOOL NSDeallocateZombies = NO;
@@ -187,8 +186,7 @@
#endif
-/*
- * Traditionally, GNUstep has been using a 32bit reference count in front
+/* Traditionally, GNUstep has been using a 32bit reference count in front
* of the object. The automatic reference counting implementation in
* libobjc2 uses an intptr_t instead, so NSObject will only be compatible
* with ARC if either of the following apply:
@@ -374,8 +372,7 @@
#if !defined(GSATOMICREAD)
-/*
- * Having just one allocationLock for all leads to lock contention
+/* Having just one allocationLock for all leads to lock contention
* if there are lots of threads doing lots of retain/release calls.
* To alleviate this, instead of a single
* allocationLock for all objects, we divide the object space into
@@ -421,7 +418,7 @@
* (before the start) in each object.
*/
typedef struct obj_layout_unpadded {
- int32_t retained;
+ gsrefcount_t retained;
} unp;
#define UNP sizeof(unp)
@@ -441,7 +438,7 @@
struct obj_layout {
char padding[__BIGGEST_ALIGNMENT__ - ((UNP % __BIGGEST_ALIGNMENT__)
? (UNP % __BIGGEST_ALIGNMENT__) : __BIGGEST_ALIGNMENT__)];
- int32_t retained;
+ gsrefcount_t retained;
};
typedef struct obj_layout *obj;
@@ -452,7 +449,7 @@
* (and hence whether the extra reference count was decremented).<br />
* This function is used by the [NSObject-release] method.
*/
-BOOL
+inline BOOL
NSDecrementExtraRefCountWasZero(id anObject)
{
if (double_release_check_enabled)
@@ -464,58 +461,45 @@
[NSException raise: NSGenericException
format: @"Release would release object too many times."];
}
- if (allocationLock != 0)
- {
+ {
#if defined(GSATOMICREAD)
- gsrefcount_t result;
-
- result = GSAtomicDecrement((gsatomic_t)&(((obj)anObject)[-1].retained));
- if (result < 0)
- {
- if (result != -1)
- {
- [NSException raise: NSInternalInconsistencyException
- format: @"NSDecrementExtraRefCount() decremented too far"];
- }
- /* The counter has become negative so it must have been zero.
- * We reset it and return YES ... in a correctly operating
- * process we know we can safely reset back to zero without
- * worrying about atomicity, since there can be no other
- * thread accessing the object (or its reference count would
- * have been greater than zero)
- */
- (((obj)anObject)[-1].retained) = 0;
- return YES;
- }
+ gsrefcount_t result;
+
+ result = GSAtomicDecrement((gsatomic_t)&(((obj)anObject)[-1].retained));
+ if (result < 0)
+ {
+ if (result != -1)
+ {
+ [NSException raise: NSInternalInconsistencyException
+ format: @"NSDecrementExtraRefCount() decremented too far"];
+ }
+ /* The counter has become negative so it must have been zero.
+ * We reset it and return YES ... in a correctly operating
+ * process we know we can safely reset back to zero without
+ * worrying about atomicity, since there can be no other
+ * thread accessing the object (or its reference count would
+ * have been greater than zero)
+ */
+ (((obj)anObject)[-1].retained) = 0;
+ return YES;
+ }
#else /* GSATOMICREAD */
- NSLock *theLock = GSAllocationLockForObject(anObject);
-
- [theLock lock];
- if (((obj)anObject)[-1].retained == 0)
- {
- [theLock unlock];
- return YES;
- }
- else
- {
- ((obj)anObject)[-1].retained--;
- [theLock unlock];
- return NO;
- }
+ NSLock *theLock = GSAllocationLockForObject(anObject);
+
+ [theLock lock];
+ if (((obj)anObject)[-1].retained == 0)
+ {
+ [theLock unlock];
+ return YES;
+ }
+ else
+ {
+ ((obj)anObject)[-1].retained--;
+ [theLock unlock];
+ return NO;
+ }
#endif /* GSATOMICREAD */
- }
- else
- {
- if (((obj)anObject)[-1].retained == 0)
- {
- return YES;
- }
- else
- {
- ((obj)anObject)[-1].retained--;
- return NO;
- }
- }
+ }
return NO;
}
@@ -539,42 +523,30 @@
inline void
NSIncrementExtraRefCount(id anObject)
{
- if (allocationLock != 0)
- {
#if defined(GSATOMICREAD)
- /* I've seen comments saying that some platforms only support up to
- * 24 bits in atomic locking, so raise an exception if we try to
- * go beyond 0xfffffe.
- */
- if (GSAtomicIncrement((gsatomic_t)&(((obj)anObject)[-1].retained))
- > 0xfffffe)
- {
- [NSException raise: NSInternalInconsistencyException
- format: @"NSIncrementExtraRefCount() asked to increment too far"];
- }
+ /* I've seen comments saying that some platforms only support up to
+ * 24 bits in atomic locking, so raise an exception if we try to
+ * go beyond 0xfffffe.
+ */
+ if (GSAtomicIncrement((gsatomic_t)&(((obj)anObject)[-1].retained))
+ > 0xfffffe)
+ {
+ [NSException raise: NSInternalInconsistencyException
+ format: @"NSIncrementExtraRefCount() asked to increment too far"];
+ }
#else /* GSATOMICREAD */
- NSLock *theLock = GSAllocationLockForObject(anObject);
-
- [theLock lock];
- if (((obj)anObject)[-1].retained > 0xfffffe)
- {
- [theLock unlock];
- [NSException raise: NSInternalInconsistencyException
- format: @"NSIncrementExtraRefCount() asked to increment too far"];
- }
- ((obj)anObject)[-1].retained++;
+ NSLock *theLock = GSAllocationLockForObject(anObject);
+
+ [theLock lock];
+ if (((obj)anObject)[-1].retained > 0xfffffe)
+ {
[theLock unlock];
+ [NSException raise: NSInternalInconsistencyException
+ format: @"NSIncrementExtraRefCount() asked to increment too far"];
+ }
+ ((obj)anObject)[-1].retained++;
+ [theLock unlock];
#endif /* GSATOMICREAD */
- }
- else
- {
- if (((obj)anObject)[-1].retained > 0xfffffe)
- {
- [NSException raise: NSInternalInconsistencyException
- format: @"NSIncrementExtraRefCount() asked to increment too far"];
- }
- ((obj)anObject)[-1].retained++;
- }
}
#ifndef NDEBUG
@@ -769,22 +741,6 @@
#if defined(GS_ARC_COMPATIBLE)
- (void)_ARCCompliantRetainRelease {}
#endif
-
-+ (void) _becomeMultiThreaded: (NSNotification *)aNotification
-{
- if (allocationLock == 0)
- {
-#if !defined(GSATOMICREAD)
- NSUInteger i;
-
- for (i = 0; i < LOCKCOUNT; i++)
- {
- allocationLocks[i] = [NSLock new];
- }
-#endif
- allocationLock = [NSLock new];
- }
-}
/**
* Semi-private function in libobjc2 that initialises the classes used for
@@ -882,6 +838,21 @@
# endif
#endif
+ /* Create the lock for NSZombie and for allocation when atomic
+ * operations are not available.
+ */
+ allocationLock = [NSLock new];
+#if !defined(GSATOMICREAD)
+ {
+ NSUInteger i;
+
+ for (i = 0; i < LOCKCOUNT; i++)
+ {
+ allocationLocks[i] = [NSLock new];
+ }
+ }
+#endif
+
/* Create the global lock.
* NB. Ths is one of the first things we do ... setting up a new lock
* must not call any other Objective-C classes and must not involve
@@ -930,15 +901,6 @@
* object, and that class hasn't been initialized yet ...
*/
zombieClass = objc_lookUpClass("NSZombie");
-
- /* Now that we have a working autorelease system and working string
- * classes we are able to set up notifications.
- */
- [[NSNotificationCenter defaultCenter]
- addObserver: self
- selector: @selector(_becomeMultiThreaded:)
- name: NSWillBecomeMultiThreadedNotification
- object: nil];
}
return;
}
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