| // boehm.cc - interface between libjava and Boehm GC. |
| |
| /* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004 |
| Free Software Foundation |
| |
| This file is part of libgcj. |
| |
| This software is copyrighted work licensed under the terms of the |
| Libgcj License. Please consult the file "LIBGCJ_LICENSE" for |
| details. */ |
| |
| #include <config.h> |
| |
| #include <stdio.h> |
| #include <limits.h> |
| |
| #include <jvm.h> |
| #include <gcj/cni.h> |
| |
| #include <java/lang/Class.h> |
| #include <java/lang/reflect/Modifier.h> |
| #include <java-interp.h> |
| |
| // More nastiness: the GC wants to define TRUE and FALSE. We don't |
| // need the Java definitions (themselves a hack), so we undefine them. |
| #undef TRUE |
| #undef FALSE |
| |
| extern "C" |
| { |
| #include <gc_config.h> |
| |
| // Set GC_DEBUG before including gc.h! |
| #ifdef LIBGCJ_GC_DEBUG |
| # define GC_DEBUG |
| #endif |
| |
| #include <gc_mark.h> |
| #include <gc_gcj.h> |
| #include <javaxfc.h> // GC_finalize_all declaration. |
| |
| #ifdef THREAD_LOCAL_ALLOC |
| # define GC_REDIRECT_TO_LOCAL |
| # include <gc_local_alloc.h> |
| #endif |
| |
| // From boehm's misc.c |
| void GC_enable(); |
| void GC_disable(); |
| }; |
| |
| #define MAYBE_MARK(Obj, Top, Limit, Source) \ |
| Top=GC_MARK_AND_PUSH((GC_PTR) Obj, Top, Limit, (GC_PTR *) Source) |
| |
| // `kind' index used when allocating Java arrays. |
| static int array_kind_x; |
| |
| // Freelist used for Java arrays. |
| static void **array_free_list; |
| |
| |
| |
| // This is called by the GC during the mark phase. It marks a Java |
| // object. We use `void *' arguments and return, and not what the |
| // Boehm GC wants, to avoid pollution in our headers. |
| void * |
| _Jv_MarkObj (void *addr, void *msp, void *msl, void *env) |
| { |
| struct GC_ms_entry *mark_stack_ptr = (struct GC_ms_entry *)msp; |
| struct GC_ms_entry *mark_stack_limit = (struct GC_ms_entry *)msl; |
| |
| if (env == (void *)1) /* Object allocated with debug allocator. */ |
| addr = (GC_PTR)GC_USR_PTR_FROM_BASE(addr); |
| jobject obj = (jobject) addr; |
| |
| _Jv_VTable *dt = *(_Jv_VTable **) addr; |
| // The object might not yet have its vtable set, or it might |
| // really be an object on the freelist. In either case, the vtable slot |
| // will either be 0, or it will point to a cleared object. |
| // This assumes Java objects have size at least 3 words, |
| // including the header. But this should remain true, since this |
| // should only be used with debugging allocation or with large objects. |
| if (__builtin_expect (! dt || !(dt -> get_finalizer()), false)) |
| return mark_stack_ptr; |
| jclass klass = dt->clas; |
| GC_PTR p; |
| |
| # ifndef JV_HASH_SYNCHRONIZATION |
| // Every object has a sync_info pointer. |
| p = (GC_PTR) obj->sync_info; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj); |
| # endif |
| // Mark the object's class. |
| p = (GC_PTR) klass; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj); |
| |
| if (__builtin_expect (klass == &java::lang::Class::class$, false)) |
| { |
| // Currently we allocate some of the memory referenced from class objects |
| // as pointerfree memory, and then mark it more intelligently here. |
| // We ensure that the ClassClass mark descriptor forces invocation of |
| // this procedure. |
| // Correctness of this is subtle, but it looks OK to me for now. For the incremental |
| // collector, we need to make sure that the class object is written whenever |
| // any of the subobjects are altered and may need rescanning. This may be tricky |
| // during construction, and this may not be the right way to do this with |
| // incremental collection. |
| // If we overflow the mark stack, we will rescan the class object, so we should |
| // be OK. The same applies if we redo the mark phase because win32 unmapped part |
| // of our root set. - HB |
| jclass c = (jclass) addr; |
| |
| p = (GC_PTR) c->name; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->superclass; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| for (int i = 0; i < c->constants.size; ++i) |
| { |
| /* FIXME: We could make this more precise by using the tags -KKT */ |
| p = (GC_PTR) c->constants.data[i].p; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| } |
| |
| #ifdef INTERPRETER |
| if (_Jv_IsInterpretedClass (c)) |
| { |
| p = (GC_PTR) c->constants.tags; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->constants.data; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| } |
| #endif |
| |
| // The vtable might be allocated even for compiled code. |
| p = (GC_PTR) c->vtable; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // If the class is an array, then the methods field holds a |
| // pointer to the element class. If the class is primitive, |
| // then the methods field holds a pointer to the array class. |
| p = (GC_PTR) c->methods; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // The vtable might have been set, but the rest of the class |
| // could still be uninitialized. If this is the case, then |
| // c.isArray will SEGV. We check for this, and if it is the |
| // case we just return. |
| if (__builtin_expect (c->name == NULL, false)) |
| return mark_stack_ptr; |
| |
| if (! c->isArray() && ! c->isPrimitive()) |
| { |
| // Scan each method in the cases where `methods' really |
| // points to a methods structure. |
| for (int i = 0; i < c->method_count; ++i) |
| { |
| p = (GC_PTR) c->methods[i].name; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->methods[i].signature; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // Note that we don't have to mark each individual throw |
| // separately, as these are stored in the constant pool. |
| p = (GC_PTR) c->methods[i].throws; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| } |
| } |
| |
| // Mark all the fields. |
| p = (GC_PTR) c->fields; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| for (int i = 0; i < c->field_count; ++i) |
| { |
| _Jv_Field* field = &c->fields[i]; |
| |
| p = (GC_PTR) field->name; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) field->type; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // For the interpreter, we also need to mark the memory |
| // containing static members |
| if ((field->flags & java::lang::reflect::Modifier::STATIC)) |
| { |
| p = (GC_PTR) field->u.addr; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // also, if the static member is a reference, |
| // mark also the value pointed to. We check for isResolved |
| // since marking can happen before memory is allocated for |
| // static members. |
| // Note that field->u.addr may be null if the class c is |
| // JV_STATE_LOADED but not JV_STATE_PREPARED (initialized). |
| if (JvFieldIsRef (field) && p && field->isResolved()) |
| { |
| jobject val = *(jobject*) p; |
| p = (GC_PTR) val; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| } |
| } |
| } |
| |
| p = (GC_PTR) c->vtable; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->interfaces; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| for (int i = 0; i < c->interface_count; ++i) |
| { |
| p = (GC_PTR) c->interfaces[i]; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| } |
| p = (GC_PTR) c->loader; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| // The dispatch tables can be allocated at runtime. |
| p = (GC_PTR) c->ancestors; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| if (c->idt) |
| { |
| p = (GC_PTR) c->idt; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| if (c->isInterface()) |
| { |
| p = (GC_PTR) c->idt->iface.ioffsets; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c->idt); |
| } |
| else if (! c->isPrimitive()) |
| { |
| // This field is only valid for ordinary classes. |
| p = (GC_PTR) c->idt->cls.itable; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c->idt); |
| } |
| } |
| |
| p = (GC_PTR) c->arrayclass; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->protectionDomain; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->hack_signers; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| p = (GC_PTR) c->aux_info; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| #ifdef INTERPRETER |
| if (_Jv_IsInterpretedClass (c) && c->aux_info) |
| { |
| _Jv_InterpClass* ic = (_Jv_InterpClass*) c->aux_info; |
| |
| p = (GC_PTR) ic->interpreted_methods; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic); |
| |
| for (int i = 0; i < c->method_count; i++) |
| { |
| // The interpreter installs a heap-allocated trampoline |
| // here, so we'll mark it. |
| p = (GC_PTR) c->methods[i].ncode; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c); |
| |
| using namespace java::lang::reflect; |
| |
| // Mark the direct-threaded code. Note a subtlety here: |
| // when we add Miranda methods to a class, we don't |
| // resize its interpreted_methods array. If we try to |
| // reference one of these methods, we may crash. |
| // However, we know these are all abstract, and we know |
| // that abstract methods have nothing useful in this |
| // array. So, we skip all abstract methods to avoid the |
| // problem. FIXME: this is pretty obscure, it may be |
| // better to add a methods to the execution engine and |
| // resize the array. |
| if ((c->methods[i].accflags & Modifier::ABSTRACT) != 0) |
| continue; |
| |
| p = (GC_PTR) ic->interpreted_methods[i]; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic); |
| |
| if ((c->methods[i].accflags & Modifier::NATIVE) != 0) |
| { |
| _Jv_JNIMethod *jm |
| = (_Jv_JNIMethod *) ic->interpreted_methods[i]; |
| if (jm) |
| { |
| p = (GC_PTR) jm->jni_arg_types; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, p); |
| } |
| } |
| else |
| { |
| _Jv_InterpMethod *im |
| = (_Jv_InterpMethod *) ic->interpreted_methods[i]; |
| if (im) |
| { |
| p = (GC_PTR) im->prepared; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic); |
| } |
| } |
| } |
| |
| p = (GC_PTR) ic->field_initializers; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic); |
| |
| } |
| #endif |
| |
| } |
| else |
| { |
| // NOTE: each class only holds information about the class |
| // itself. So we must do the marking for the entire inheritance |
| // tree in order to mark all fields. FIXME: what about |
| // interfaces? We skip Object here, because Object only has a |
| // sync_info, and we handled that earlier. |
| // Note: occasionally `klass' can be null. For instance, this |
| // can happen if a GC occurs between the point where an object |
| // is allocated and where the vtbl slot is set. |
| while (klass && klass != &java::lang::Object::class$) |
| { |
| jfieldID field = JvGetFirstInstanceField (klass); |
| jint max = JvNumInstanceFields (klass); |
| |
| for (int i = 0; i < max; ++i) |
| { |
| if (JvFieldIsRef (field)) |
| { |
| jobject val = JvGetObjectField (obj, field); |
| p = (GC_PTR) val; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj); |
| } |
| field = field->getNextField (); |
| } |
| klass = klass->getSuperclass(); |
| } |
| } |
| |
| return mark_stack_ptr; |
| } |
| |
| // This is called by the GC during the mark phase. It marks a Java |
| // array (of objects). We use `void *' arguments and return, and not |
| // what the Boehm GC wants, to avoid pollution in our headers. |
| void * |
| _Jv_MarkArray (void *addr, void *msp, void *msl, void *env) |
| { |
| struct GC_ms_entry *mark_stack_ptr = (struct GC_ms_entry *)msp; |
| struct GC_ms_entry *mark_stack_limit = (struct GC_ms_entry *)msl; |
| |
| if (env == (void *)1) /* Object allocated with debug allocator. */ |
| addr = (void *)GC_USR_PTR_FROM_BASE(addr); |
| jobjectArray array = (jobjectArray) addr; |
| |
| _Jv_VTable *dt = *(_Jv_VTable **) addr; |
| // Assumes size >= 3 words. That's currently true since arrays have |
| // a vtable, sync pointer, and size. If the sync pointer goes away, |
| // we may need to round up the size. |
| if (__builtin_expect (! dt || !(dt -> get_finalizer()), false)) |
| return mark_stack_ptr; |
| jclass klass = dt->clas; |
| GC_PTR p; |
| |
| # ifndef JV_HASH_SYNCHRONIZATION |
| // Every object has a sync_info pointer. |
| p = (GC_PTR) array->sync_info; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, array); |
| # endif |
| // Mark the object's class. |
| p = (GC_PTR) klass; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, &(dt -> clas)); |
| |
| for (int i = 0; i < JvGetArrayLength (array); ++i) |
| { |
| jobject obj = elements (array)[i]; |
| p = (GC_PTR) obj; |
| MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, array); |
| } |
| |
| return mark_stack_ptr; |
| } |
| |
| // Generate a GC marking descriptor for a class. |
| // |
| // We assume that the gcj mark proc has index 0. This is a dubious assumption, |
| // since another one could be registered first. But the compiler also |
| // knows this, so in that case everything else will break, too. |
| #define GCJ_DEFAULT_DESCR GC_MAKE_PROC(GC_GCJ_RESERVED_MARK_PROC_INDEX,0) |
| |
| void * |
| _Jv_BuildGCDescr(jclass self) |
| { |
| jlong desc = 0; |
| jint bits_per_word = CHAR_BIT * sizeof (void *); |
| |
| // Note: for now we only consider a bitmap mark descriptor. We |
| // could also handle the case where the first N fields of a type are |
| // references. However, this is not very likely to be used by many |
| // classes, and it is easier to compute things this way. |
| |
| // The vtable pointer. |
| desc |= 1ULL << (bits_per_word - 1); |
| #ifndef JV_HASH_SYNCHRONIZATION |
| // The sync_info field. |
| desc |= 1ULL << (bits_per_word - 2); |
| #endif |
| |
| for (jclass klass = self; klass != NULL; klass = klass->getSuperclass()) |
| { |
| jfieldID field = JvGetFirstInstanceField(klass); |
| int count = JvNumInstanceFields(klass); |
| |
| for (int i = 0; i < count; ++i) |
| { |
| if (field->isRef()) |
| { |
| unsigned int off = field->getOffset(); |
| // If we run into a weird situation, we bail. |
| if (off % sizeof (void *) != 0) |
| return (void *) (GCJ_DEFAULT_DESCR); |
| off /= sizeof (void *); |
| // If we find a field outside the range of our bitmap, |
| // fall back to procedure marker. The bottom 2 bits are |
| // reserved. |
| if (off >= (unsigned) bits_per_word - 2) |
| return (void *) (GCJ_DEFAULT_DESCR); |
| desc |= 1ULL << (bits_per_word - off - 1); |
| } |
| |
| field = field->getNextField(); |
| } |
| } |
| |
| // For bitmap mark type, bottom bits are 01. |
| desc |= 1; |
| // Bogus warning avoidance (on many platforms). |
| return (void *) (unsigned long) desc; |
| } |
| |
| // Allocate some space that is known to be pointer-free. |
| void * |
| _Jv_AllocBytes (jsize size) |
| { |
| void *r = GC_MALLOC_ATOMIC (size); |
| // We have to explicitly zero memory here, as the GC doesn't |
| // guarantee that PTRFREE allocations are zeroed. Note that we |
| // don't have to do this for other allocation types because we set |
| // the `ok_init' flag in the type descriptor. |
| memset (r, 0, size); |
| return r; |
| } |
| |
| #ifdef LIBGCJ_GC_DEBUG |
| |
| void * |
| _Jv_AllocObj (jsize size, jclass klass) |
| { |
| return GC_GCJ_MALLOC (size, klass->vtable); |
| } |
| |
| void * |
| _Jv_AllocPtrFreeObj (jsize size, jclass klass) |
| { |
| #ifdef JV_HASH_SYNCHRONIZATION |
| void * obj = GC_MALLOC_ATOMIC(size); |
| *((_Jv_VTable **) obj) = klass->vtable; |
| #else |
| void * obj = GC_GCJ_MALLOC(size, klass->vtable); |
| #endif |
| return obj; |
| } |
| |
| #endif /* LIBGCJ_GC_DEBUG */ |
| // In the non-debug case, the above two functions are defined |
| // as inline functions in boehm-gc.h. In the debug case we |
| // really want to take advantage of the definitions in gc_gcj.h. |
| |
| // Allocate space for a new Java array. |
| // Used only for arrays of objects. |
| void * |
| _Jv_AllocArray (jsize size, jclass klass) |
| { |
| void *obj; |
| |
| #ifdef LIBGCJ_GC_DEBUG |
| // There isn't much to lose by scanning this conservatively. |
| // If we didn't, the mark proc would have to understand that |
| // it needed to skip the header. |
| obj = GC_MALLOC(size); |
| #else |
| const jsize min_heap_addr = 16*1024; |
| // A heuristic. If size is less than this value, the size |
| // stored in the array can't possibly be misinterpreted as |
| // a pointer. Thus we lose nothing by scanning the object |
| // completely conservatively, since no misidentification can |
| // take place. |
| |
| if (size < min_heap_addr) |
| obj = GC_MALLOC(size); |
| else |
| obj = GC_generic_malloc (size, array_kind_x); |
| #endif |
| *((_Jv_VTable **) obj) = klass->vtable; |
| return obj; |
| } |
| |
| /* Allocate space for a new non-Java object, which does not have the usual |
| Java object header but may contain pointers to other GC'ed objects. */ |
| void * |
| _Jv_AllocRawObj (jsize size) |
| { |
| return (void *) GC_MALLOC (size); |
| } |
| |
| static void |
| call_finalizer (GC_PTR obj, GC_PTR client_data) |
| { |
| _Jv_FinalizerFunc *fn = (_Jv_FinalizerFunc *) client_data; |
| jobject jobj = (jobject) obj; |
| |
| (*fn) (jobj); |
| } |
| |
| void |
| _Jv_RegisterFinalizer (void *object, _Jv_FinalizerFunc *meth) |
| { |
| GC_REGISTER_FINALIZER_NO_ORDER (object, call_finalizer, (GC_PTR) meth, |
| NULL, NULL); |
| } |
| |
| void |
| _Jv_RunFinalizers (void) |
| { |
| GC_invoke_finalizers (); |
| } |
| |
| void |
| _Jv_RunAllFinalizers (void) |
| { |
| GC_finalize_all (); |
| } |
| |
| void |
| _Jv_RunGC (void) |
| { |
| GC_gcollect (); |
| } |
| |
| long |
| _Jv_GCTotalMemory (void) |
| { |
| return GC_get_heap_size (); |
| } |
| |
| long |
| _Jv_GCFreeMemory (void) |
| { |
| return GC_get_free_bytes (); |
| } |
| |
| void |
| _Jv_GCSetInitialHeapSize (size_t size) |
| { |
| size_t current = GC_get_heap_size (); |
| if (size > current) |
| GC_expand_hp (size - current); |
| } |
| |
| void |
| _Jv_GCSetMaximumHeapSize (size_t size) |
| { |
| GC_set_max_heap_size ((GC_word) size); |
| } |
| |
| void |
| _Jv_DisableGC (void) |
| { |
| GC_disable(); |
| } |
| |
| void |
| _Jv_EnableGC (void) |
| { |
| GC_enable(); |
| } |
| |
| static void * handle_out_of_memory(size_t) |
| { |
| _Jv_ThrowNoMemory(); |
| } |
| |
| static void |
| gcj_describe_type_fn(void *obj, char *out_buf) |
| { |
| _Jv_VTable *dt = *(_Jv_VTable **) obj; |
| |
| if (! dt /* Shouldn't happen */) |
| { |
| strcpy(out_buf, "GCJ (bad)"); |
| return; |
| } |
| jclass klass = dt->clas; |
| if (!klass /* shouldn't happen */) |
| { |
| strcpy(out_buf, "GCJ (bad)"); |
| return; |
| } |
| jstring name = klass -> getName(); |
| size_t len = name -> length(); |
| if (len >= GC_TYPE_DESCR_LEN) len = GC_TYPE_DESCR_LEN - 1; |
| JvGetStringUTFRegion (name, 0, len, out_buf); |
| out_buf[len] = '\0'; |
| } |
| |
| void |
| _Jv_InitGC (void) |
| { |
| int proc; |
| |
| // Ignore pointers that do not point to the start of an object. |
| GC_all_interior_pointers = 0; |
| |
| // Configure the collector to use the bitmap marking descriptors that we |
| // stash in the class vtable. |
| // We always use mark proc descriptor 0, since the compiler knows |
| // about it. |
| GC_init_gcj_malloc (0, (void *) _Jv_MarkObj); |
| |
| // Cause an out of memory error to be thrown from the allocators, |
| // instead of returning 0. This is cheaper than checking on allocation. |
| GC_oom_fn = handle_out_of_memory; |
| |
| GC_java_finalization = 1; |
| |
| // We use a different mark procedure for object arrays. This code |
| // configures a different object `kind' for object array allocation and |
| // marking. |
| array_free_list = GC_new_free_list(); |
| proc = GC_new_proc((GC_mark_proc)_Jv_MarkArray); |
| array_kind_x = GC_new_kind(array_free_list, GC_MAKE_PROC (proc, 0), 0, 1); |
| |
| // Arrange to have the GC print Java class names in backtraces, etc. |
| GC_register_describe_type_fn(GC_gcj_kind, gcj_describe_type_fn); |
| GC_register_describe_type_fn(GC_gcj_debug_kind, gcj_describe_type_fn); |
| } |
| |
| #ifdef JV_HASH_SYNCHRONIZATION |
| // Allocate an object with a fake vtable pointer, which causes only |
| // the first field (beyond the fake vtable pointer) to be traced. |
| // Eventually this should probably be generalized. |
| |
| static _Jv_VTable trace_one_vtable = { |
| 0, // class pointer |
| (void *)(2 * sizeof(void *)), |
| // descriptor; scan 2 words incl. vtable ptr. |
| // Least significant bits must be zero to |
| // identify this as a length descriptor |
| {0} // First method |
| }; |
| |
| void * |
| _Jv_AllocTraceOne (jsize size /* includes vtable slot */) |
| { |
| return GC_GCJ_MALLOC (size, &trace_one_vtable); |
| } |
| |
| // Ditto for two words. |
| // the first field (beyond the fake vtable pointer) to be traced. |
| // Eventually this should probably be generalized. |
| |
| static _Jv_VTable trace_two_vtable = |
| { |
| 0, // class pointer |
| (void *)(3 * sizeof(void *)), |
| // descriptor; scan 3 words incl. vtable ptr. |
| {0} // First method |
| }; |
| |
| void * |
| _Jv_AllocTraceTwo (jsize size /* includes vtable slot */) |
| { |
| return GC_GCJ_MALLOC (size, &trace_two_vtable); |
| } |
| |
| #endif /* JV_HASH_SYNCHRONIZATION */ |
| |
| void |
| _Jv_GCInitializeFinalizers (void (*notifier) (void)) |
| { |
| GC_finalize_on_demand = 1; |
| GC_finalizer_notifier = notifier; |
| } |
| |
| void |
| _Jv_GCRegisterDisappearingLink (jobject *objp) |
| { |
| // This test helps to ensure that we meet a precondition of |
| // GC_general_register_disappearing_link, viz. "Obj must be a |
| // pointer to the first word of an object we allocated." |
| if (GC_base(*objp)) |
| GC_general_register_disappearing_link ((GC_PTR *) objp, (GC_PTR) *objp); |
| } |
| |
| jboolean |
| _Jv_GCCanReclaimSoftReference (jobject) |
| { |
| // For now, always reclaim soft references. FIXME. |
| return true; |
| } |