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Add marking of an instance as having been weakly referenced.

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rfm 2024-12-25 12:19:33 +00:00
parent 927e97eaac
commit 882ded1a05
3 changed files with 46 additions and 6 deletions
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1
Source/GSPrivate.h
View file

@ -641,6 +641,7 @@ GSPrivateEncodeBase64(const uint8_t *src, NSUInteger length, uint8_t *dst)
/* When we don't have a runtime with ARC to support weak references, we
* use our own version.
*/
BOOL GSPrivateMarkedWeak(id obj, BOOL mark) GS_ATTRIB_PRIVATE;
void GSWeakInit() GS_ATTRIB_PRIVATE;
BOOL objc_delete_weak_refs(id obj);
#endif

40
Source/NSObject.m
View file

@ -208,8 +208,7 @@ extern void GSLogZombie(id o, SEL sel)
#undef GSATOMICREAD
#endif
#if defined(__llvm__) || (defined(USE_ATOMIC_BUILTINS) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)))
/* Use the GCC atomic operations with recent GCC versions */
#ifdef OBJC_CAP_ARC
typedef intptr_t volatile *gsatomic_t;
typedef intptr_t gsrefcount_t;
@ -217,6 +216,15 @@ typedef intptr_t gsrefcount_t;
#define GSAtomicIncrement(X) __sync_add_and_fetch(X, 1)
#define GSAtomicDecrement(X) __sync_sub_and_fetch(X, 1)
#elif (defined(USE_ATOMIC_BUILTINS) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)))
/* Use the GCC atomic operations with recent GCC versions */
typedef int32_t volatile *gsatomic_t;
typedef int32_t gsrefcount_t;
#define GSATOMICREAD(X) (*(X))
#define GSAtomicIncrement(X) __sync_add_and_fetch(X, 1)
#define GSAtomicDecrement(X) __sync_sub_and_fetch(X, 1)
#elif defined(_WIN32)
/* Set up atomic read, increment and decrement for mswindows
@ -382,7 +390,7 @@ GSAtomicDecrement(gsatomic_t X)
#include <pthread.h>
typedef int gsrefcount_t; // No atomics, use a simple integer
typedef int32_t gsrefcount_t; // No atomics, use a simple integer
/* Having just one allocationLock for all leads to lock contention
* if there are lots of threads doing lots of retain/release calls.
@ -415,12 +423,21 @@ static inline pthread_mutex_t *GSAllocationLockForObject(id p)
#endif
#define alignof(type) __builtin_offsetof(struct { const char c; type member; }, member)
#ifndef OBJC_CAP_ARC
typedef struct {
BOOL hadWeakReference: 1; // set if the instance ever had a weak reference
} gsinstinfo_t;
#endif
/*
* Define a structure to hold information that is held locally
* (before the start) in each object.
*/
typedef struct obj_layout_unpadded {
gsrefcount_t retained;
#ifndef OBJC_CAP_ARC
gsinstinfo_t extra;
#endif
} unp;
#define UNP sizeof(unp)
@ -441,9 +458,26 @@ struct obj_layout {
char padding[__BIGGEST_ALIGNMENT__ - ((UNP % __BIGGEST_ALIGNMENT__)
? (UNP % __BIGGEST_ALIGNMENT__) : __BIGGEST_ALIGNMENT__)];
gsrefcount_t retained;
#ifndef OBJC_CAP_ARC
gsinstinfo_t extra;
#endif
};
typedef struct obj_layout *obj;
#ifndef OBJC_CAP_ARC
BOOL
GSPrivateMarkedWeak(id anObject, BOOL mark)
{
BOOL wasMarked = ((obj)anObject)[-1].extra.hadWeakReference;
if (mark)
{
((obj)anObject)[-1].extra.hadWeakReference = YES;
}
return wasMarked;
}
#endif
/*
* These symbols are provided by newer versions of the GNUstep Objective-C
* runtime. When linked against an older version, we will use our internal

11
Source/ObjectiveC2/weak.m
View file

@ -171,6 +171,11 @@ incrementWeakRefCount(id obj)
GSIMapKey key;
GSIMapBucket bucket;
WeakRef *ref;
/* Mark the instance as having had a weak reference at some point.
* This information is used when the instance is deallocated.
*/
GSPrivateMarkedWeak(obj, YES);
key.obj = obj;
bucket = GSIMapBucketForKey(&weakRefs, key);
@ -254,11 +259,11 @@ objc_delete_weak_refs(id obj)
GSIMapBucket bucket;
WeakRef *ref;
/* FIXME ... for performance we should have marked the object as having
* weak references and we should check that in order to avoid the cost
/* For performance we should have marked the object as having
* weak references and we check that in order to avoid the cost
* of the map table lookup when it's not needed.
*/
if (0)
if (NO == GSPrivateMarkedWeak(obj, NO))
{
return NO;
}