1 // link.cc - Code for linking and resolving classes and pool entries.
3 /* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
11 /* Author: Kresten Krab Thorup <krab@gnu.org> */
18 #include <java-interp.h>
24 #include <java-cpool.h>
25 #include <execution.h>
26 #include <java/lang/Class.h>
27 #include <java/lang/String.h>
28 #include <java/lang/StringBuffer.h>
29 #include <java/lang/Thread.h>
30 #include <java/lang/InternalError.h>
31 #include <java/lang/VirtualMachineError.h>
32 #include <java/lang/VerifyError.h>
33 #include <java/lang/NoSuchFieldError.h>
34 #include <java/lang/NoSuchMethodError.h>
35 #include <java/lang/ClassFormatError.h>
36 #include <java/lang/IllegalAccessError.h>
37 #include <java/lang/InternalError.h>
38 #include <java/lang/AbstractMethodError.h>
39 #include <java/lang/NoClassDefFoundError.h>
40 #include <java/lang/IncompatibleClassChangeError.h>
41 #include <java/lang/VerifyError.h>
42 #include <java/lang/VMClassLoader.h>
43 #include <java/lang/reflect/Modifier.h>
44 #include <java/security/CodeSource.h>
48 typedef unsigned int uaddr __attribute__ ((mode (pointer)));
57 #define ALIGNOF(TYPE) (offsetof (aligner<TYPE>, field))
59 // This returns the alignment of a type as it would appear in a
60 // structure. This can be different from the alignment of the type
61 // itself. For instance on x86 double is 8-aligned but struct{double}
64 _Jv_Linker::get_alignment_from_class (jclass klass)
66 if (klass == JvPrimClass (byte))
67 return ALIGNOF (jbyte);
68 else if (klass == JvPrimClass (short))
69 return ALIGNOF (jshort);
70 else if (klass == JvPrimClass (int))
71 return ALIGNOF (jint);
72 else if (klass == JvPrimClass (long))
73 return ALIGNOF (jlong);
74 else if (klass == JvPrimClass (boolean))
75 return ALIGNOF (jboolean);
76 else if (klass == JvPrimClass (char))
77 return ALIGNOF (jchar);
78 else if (klass == JvPrimClass (float))
79 return ALIGNOF (jfloat);
80 else if (klass == JvPrimClass (double))
81 return ALIGNOF (jdouble);
83 return ALIGNOF (jobject);
87 _Jv_Linker::resolve_field (_Jv_Field *field, java::lang::ClassLoader *loader)
89 if (! field->isResolved ())
91 _Jv_Utf8Const *sig = (_Jv_Utf8Const *) field->type;
92 jclass type = _Jv_FindClassFromSignature (sig->chars(), loader);
94 throw new java::lang::NoClassDefFoundError(field->name->toString());
96 field->flags &= ~_Jv_FIELD_UNRESOLVED_FLAG;
100 // A helper for find_field that knows how to recursively search
101 // superclasses and interfaces.
103 _Jv_Linker::find_field_helper (jclass search, _Jv_Utf8Const *name,
104 _Jv_Utf8Const *type_name, jclass type,
109 // From 5.4.3.2. First search class itself.
110 for (int i = 0; i < search->field_count; ++i)
112 _Jv_Field *field = &search->fields[i];
113 if (! _Jv_equalUtf8Consts (field->name, name))
116 // Checks for the odd situation where we were able to retrieve the
117 // field's class from signature but the resolution of the field itself
118 // failed which means a different class was resolved.
123 resolve_field (field, search->loader);
125 catch (java::lang::Throwable *exc)
127 java::lang::LinkageError *le = new java::lang::LinkageError
129 ("field type mismatch with different loaders"));
137 // Note that we compare type names and not types. This is
138 // bizarre, but we do it because we want to find a field
139 // (and terminate the search) if it has the correct
140 // descriptor -- but then later reject it if the class
141 // loader check results in different classes. We can't just
142 // pass in the descriptor and check that way, because when
143 // the field is already resolved there is no easy way to
144 // find its descriptor again.
145 if ( (field->isResolved () ?
146 _Jv_equalUtf8Classnames (type_name, field->type->name) :
147 _Jv_equalUtf8Classnames (
148 type_name, (_Jv_Utf8Const *) field->type)) )
155 // Next search direct interfaces.
156 for (int i = 0; i < search->interface_count; ++i)
158 _Jv_Field *result = find_field_helper (search->interfaces[i], name,
159 type_name, type, declarer);
164 // Now search superclass.
165 search = search->superclass;
172 _Jv_Linker::has_field_p (jclass search, _Jv_Utf8Const *field_name)
174 for (int i = 0; i < search->field_count; ++i)
176 _Jv_Field *field = &search->fields[i];
177 if (_Jv_equalUtf8Consts (field->name, field_name))
184 // KLASS is the class that is requesting the field.
185 // OWNER is the class in which the field should be found.
186 // FIELD_TYPE_NAME is the type descriptor for the field.
187 // Fill FOUND_CLASS with the address of the class in which the field
188 // is actually declared.
189 // This function does the class loader type checks, and
190 // also access checks. Returns the field, or throws an
191 // exception on error.
193 _Jv_Linker::find_field (jclass klass, jclass owner,
195 _Jv_Utf8Const *field_name,
196 _Jv_Utf8Const *field_type_name)
198 // FIXME: this allocates a _Jv_Utf8Const each time. We should make
200 // Note: This call will resolve the primitive type names ("Z", "B", ...) to
201 // their Java counterparts ("boolean", "byte", ...) if accessed via
202 // field_type->name later. Using these variants of the type name is in turn
203 // important for the find_field_helper function. However if the class
204 // resolution failed then we can only use the already given type name.
206 = _Jv_FindClassFromSignatureNoException (field_type_name->chars(),
210 = find_field_helper (owner, field_name,
214 field_type, found_class);
218 java::lang::StringBuffer *sb = new java::lang::StringBuffer();
219 sb->append(JvNewStringLatin1("field "));
220 sb->append(owner->getName());
221 sb->append(JvNewStringLatin1("."));
222 sb->append(_Jv_NewStringUTF(field_name->chars()));
223 sb->append(JvNewStringLatin1(" was not found."));
224 throw new java::lang::NoSuchFieldError (sb->toString());
227 // Accept it when the field's class could not be resolved.
228 if (field_type == NULL)
229 // Silently ignore that we were not able to retrieve the type to make it
230 // possible to run code which does not access this field.
233 if (_Jv_CheckAccess (klass, *found_class, the_field->flags))
235 // Note that the field returned by find_field_helper is always
236 // resolved. There's no point checking class loaders here,
237 // since we already did the work to look up all the types.
238 // FIXME: being lazy here would be nice.
239 if (the_field->type != field_type)
240 throw new java::lang::LinkageError
242 ("field type mismatch with different loaders"));
246 java::lang::StringBuffer *sb
247 = new java::lang::StringBuffer ();
248 sb->append(klass->getName());
249 sb->append(JvNewStringLatin1(": "));
250 sb->append((*found_class)->getName());
251 sb->append(JvNewStringLatin1("."));
252 sb->append(_Jv_NewStringUtf8Const (field_name));
253 throw new java::lang::IllegalAccessError(sb->toString());
260 _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
262 using namespace java::lang::reflect;
264 _Jv_Constants *pool = &klass->constants;
266 if ((pool->tags[index] & JV_CONSTANT_ResolvedFlag) != 0)
267 return pool->data[index];
269 switch (pool->tags[index])
271 case JV_CONSTANT_Class:
273 _Jv_Utf8Const *name = pool->data[index].utf8;
276 if (name->first() == '[')
277 found = _Jv_FindClassFromSignatureNoException (name->chars(),
280 found = _Jv_FindClassNoException (name, klass->loader);
282 // If the class could not be loaded a phantom class is created. Any
283 // function that deals with such a class but cannot do something useful
284 // with it should just throw a NoClassDefFoundError with the class'
289 found = _Jv_NewClass(name, NULL, NULL);
290 found->state = JV_STATE_PHANTOM;
291 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
292 pool->data[index].clazz = found;
296 throw new java::lang::NoClassDefFoundError (name->toString());
298 // Check accessibility, but first strip array types as
299 // _Jv_ClassNameSamePackage can't handle arrays.
302 check && check->isArray();
303 check = check->getComponentType())
305 if ((found->accflags & Modifier::PUBLIC) == Modifier::PUBLIC
306 || (_Jv_ClassNameSamePackage (check->name,
309 pool->data[index].clazz = found;
310 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
314 java::lang::StringBuffer *sb = new java::lang::StringBuffer ();
315 sb->append(klass->getName());
316 sb->append(JvNewStringLatin1(" can't access class "));
317 sb->append(found->getName());
318 throw new java::lang::IllegalAccessError(sb->toString());
323 case JV_CONSTANT_String:
326 str = _Jv_NewStringUtf8Const (pool->data[index].utf8);
327 pool->data[index].o = str;
328 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
332 case JV_CONSTANT_Fieldref:
334 _Jv_ushort class_index, name_and_type_index;
335 _Jv_loadIndexes (&pool->data[index],
337 name_and_type_index);
338 jclass owner = (resolve_pool_entry (klass, class_index, true)).clazz;
340 // If a phantom class was resolved our field reference is
341 // unusable because of the missing class.
342 if (owner->state == JV_STATE_PHANTOM)
343 throw new java::lang::NoClassDefFoundError(owner->getName());
346 _Jv_InitClass (owner);
348 _Jv_ushort name_index, type_index;
349 _Jv_loadIndexes (&pool->data[name_and_type_index],
353 _Jv_Utf8Const *field_name = pool->data[name_index].utf8;
354 _Jv_Utf8Const *field_type_name = pool->data[type_index].utf8;
356 jclass found_class = 0;
357 _Jv_Field *the_field = find_field (klass, owner,
361 if (owner != found_class)
362 _Jv_InitClass (found_class);
363 pool->data[index].field = the_field;
364 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
368 case JV_CONSTANT_Methodref:
369 case JV_CONSTANT_InterfaceMethodref:
371 _Jv_ushort class_index, name_and_type_index;
372 _Jv_loadIndexes (&pool->data[index],
374 name_and_type_index);
375 jclass owner = (resolve_pool_entry (klass, class_index)).clazz;
378 _Jv_InitClass (owner);
380 _Jv_ushort name_index, type_index;
381 _Jv_loadIndexes (&pool->data[name_and_type_index],
385 _Jv_Utf8Const *method_name = pool->data[name_index].utf8;
386 _Jv_Utf8Const *method_signature = pool->data[type_index].utf8;
388 _Jv_Method *the_method = 0;
389 jclass found_class = 0;
391 // We're going to cache a pointer to the _Jv_Method object
392 // when we find it. So, to ensure this doesn't get moved from
393 // beneath us, we first put all the needed Miranda methods
394 // into the target class.
395 wait_for_state (klass, JV_STATE_LOADED);
397 // First search the class itself.
398 the_method = search_method_in_class (owner, klass,
399 method_name, method_signature);
404 goto end_of_method_search;
407 // If we are resolving an interface method, search the
408 // interface's superinterfaces (A superinterface is not an
409 // interface's superclass - a superinterface is implemented by
411 if (pool->tags[index] == JV_CONSTANT_InterfaceMethodref)
416 ifaces.list = (jclass *) _Jv_Malloc (ifaces.len
417 * sizeof (jclass *));
419 get_interfaces (owner, &ifaces);
421 for (int i = 0; i < ifaces.count; i++)
423 jclass cls = ifaces.list[i];
424 the_method = search_method_in_class (cls, klass, method_name,
433 _Jv_Free (ifaces.list);
436 goto end_of_method_search;
439 // Finally, search superclasses.
440 for (jclass cls = owner->getSuperclass (); cls != 0;
441 cls = cls->getSuperclass ())
443 the_method = search_method_in_class (cls, klass, method_name,
452 end_of_method_search:
454 // FIXME: if (cls->loader != klass->loader), then we
455 // must actually check that the types of arguments
456 // correspond. That is, for each argument type, and
457 // the return type, doing _Jv_FindClassFromSignature
458 // with either loader should produce the same result,
459 // i.e., exactly the same jclass object. JVMS 5.4.3.3
463 java::lang::StringBuffer *sb = new java::lang::StringBuffer();
464 sb->append(JvNewStringLatin1("method "));
465 sb->append(owner->getName());
466 sb->append(JvNewStringLatin1("."));
467 sb->append(_Jv_NewStringUTF(method_name->chars()));
468 sb->append(JvNewStringLatin1(" with signature "));
469 sb->append(_Jv_NewStringUTF(method_signature->chars()));
470 sb->append(JvNewStringLatin1(" was not found."));
471 throw new java::lang::NoSuchMethodError (sb->toString());
474 int vtable_index = -1;
475 if (pool->tags[index] != JV_CONSTANT_InterfaceMethodref)
476 vtable_index = (jshort)the_method->index;
478 pool->data[index].rmethod
479 = klass->engine->resolve_method(the_method,
481 ((the_method->accflags
482 & Modifier::STATIC) != 0),
484 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
488 return pool->data[index];
491 // This function is used to lazily locate superclasses and
492 // superinterfaces. This must be called with the class lock held.
494 _Jv_Linker::resolve_class_ref (jclass klass, jclass *classref)
496 jclass ret = *classref;
498 // If superclass looks like a constant pool entry, resolve it now.
499 if (ret && (uaddr) ret < (uaddr) klass->constants.size)
501 if (klass->state < JV_STATE_LINKED)
503 _Jv_Utf8Const *name = klass->constants.data[(uaddr) *classref].utf8;
504 ret = _Jv_FindClass (name, klass->loader);
507 throw new java::lang::NoClassDefFoundError (name->toString());
511 ret = klass->constants.data[(uaddr) classref].clazz;
516 // Find a method declared in the cls that is referenced from klass and
517 // perform access checks.
519 _Jv_Linker::search_method_in_class (jclass cls, jclass klass,
520 _Jv_Utf8Const *method_name,
521 _Jv_Utf8Const *method_signature)
523 using namespace java::lang::reflect;
525 for (int i = 0; i < cls->method_count; i++)
527 _Jv_Method *method = &cls->methods[i];
528 if ( (!_Jv_equalUtf8Consts (method->name,
530 || (!_Jv_equalUtf8Consts (method->signature,
534 if (_Jv_CheckAccess (klass, cls, method->accflags))
538 java::lang::StringBuffer *sb = new java::lang::StringBuffer();
539 sb->append(klass->getName());
540 sb->append(JvNewStringLatin1(": "));
541 sb->append(cls->getName());
542 sb->append(JvNewStringLatin1("."));
543 sb->append(_Jv_NewStringUTF(method_name->chars()));
544 sb->append(_Jv_NewStringUTF(method_signature->chars()));
545 throw new java::lang::IllegalAccessError (sb->toString());
552 #define INITIAL_IOFFSETS_LEN 4
553 #define INITIAL_IFACES_LEN 4
555 static _Jv_IDispatchTable null_idt = { {SHRT_MAX, 0, NULL} };
557 // Generate tables for constant-time assignment testing and interface
558 // method lookup. This implements the technique described by Per Bothner
559 // <per@bothner.com> on the java-discuss mailing list on 1999-09-02:
560 // http://gcc.gnu.org/ml/java/1999-q3/msg00377.html
562 _Jv_Linker::prepare_constant_time_tables (jclass klass)
564 if (klass->isPrimitive () || klass->isInterface ())
567 // Short-circuit in case we've been called already.
568 if ((klass->idt != NULL) || klass->depth != 0)
571 // Calculate the class depth and ancestor table. The depth of a class
572 // is how many "extends" it is removed from Object. Thus the depth of
573 // java.lang.Object is 0, but the depth of java.io.FilterOutputStream
574 // is 2. Depth is defined for all regular and array classes, but not
575 // interfaces or primitive types.
577 jclass klass0 = klass;
578 jboolean has_interfaces = 0;
579 while (klass0 != &java::lang::Object::class$)
581 has_interfaces += klass0->interface_count;
582 klass0 = klass0->superclass;
586 // We do class member testing in constant time by using a small table
587 // of all the ancestor classes within each class. The first element is
588 // a pointer to the current class, and the rest are pointers to the
589 // classes ancestors, ordered from the current class down by decreasing
590 // depth. We do not include java.lang.Object in the table of ancestors,
591 // since it is redundant. Note that the classes pointed to by
592 // 'ancestors' will always be reachable by other paths.
594 klass->ancestors = (jclass *) _Jv_AllocBytes (klass->depth
597 for (int index = 0; index < klass->depth; index++)
599 klass->ancestors[index] = klass0;
600 klass0 = klass0->superclass;
603 if ((klass->accflags & java::lang::reflect::Modifier::ABSTRACT) != 0)
606 // Optimization: If class implements no interfaces, use a common
607 // predefined interface table.
610 klass->idt = &null_idt;
615 (_Jv_IDispatchTable *) _Jv_AllocRawObj (sizeof (_Jv_IDispatchTable));
619 ifaces.len = INITIAL_IFACES_LEN;
620 ifaces.list = (jclass *) _Jv_Malloc (ifaces.len * sizeof (jclass *));
622 int itable_size = get_interfaces (klass, &ifaces);
624 if (ifaces.count > 0)
626 // The classes pointed to by the itable will always be reachable
628 klass->idt->cls.itable =
629 (void **) _Jv_AllocBytes (itable_size * sizeof (void *));
630 klass->idt->cls.itable_length = itable_size;
632 jshort *itable_offsets =
633 (jshort *) _Jv_Malloc (ifaces.count * sizeof (jshort));
635 generate_itable (klass, &ifaces, itable_offsets);
637 jshort cls_iindex = find_iindex (ifaces.list, itable_offsets,
640 for (int i = 0; i < ifaces.count; i++)
642 ifaces.list[i]->idt->iface.ioffsets[cls_iindex] =
646 klass->idt->cls.iindex = cls_iindex;
648 _Jv_Free (ifaces.list);
649 _Jv_Free (itable_offsets);
653 klass->idt->cls.iindex = SHRT_MAX;
657 // Return index of item in list, or -1 if item is not present.
659 _Jv_Linker::indexof (void *item, void **list, jshort list_len)
661 for (int i=0; i < list_len; i++)
669 // Find all unique interfaces directly or indirectly implemented by klass.
670 // Returns the size of the interface dispatch table (itable) for klass, which
671 // is the number of unique interfaces plus the total number of methods that
672 // those interfaces declare. May extend ifaces if required.
674 _Jv_Linker::get_interfaces (jclass klass, _Jv_ifaces *ifaces)
678 for (int i = 0; i < klass->interface_count; i++)
680 jclass iface = klass->interfaces[i];
682 /* Make sure interface is linked. */
683 wait_for_state(iface, JV_STATE_LINKED);
685 if (indexof (iface, (void **) ifaces->list, ifaces->count) == -1)
687 if (ifaces->count + 1 >= ifaces->len)
689 /* Resize ifaces list */
690 ifaces->len = ifaces->len * 2;
692 = (jclass *) _Jv_Realloc (ifaces->list,
693 ifaces->len * sizeof(jclass));
695 ifaces->list[ifaces->count] = iface;
698 result += get_interfaces (klass->interfaces[i], ifaces);
702 if (klass->isInterface())
703 result += klass->method_count + 1;
704 else if (klass->superclass)
705 result += get_interfaces (klass->superclass, ifaces);
709 // Fill out itable in klass, resolving method declarations in each ifaces.
710 // itable_offsets is filled out with the position of each iface in itable,
711 // such that itable[itable_offsets[n]] == ifaces.list[n].
713 _Jv_Linker::generate_itable (jclass klass, _Jv_ifaces *ifaces,
714 jshort *itable_offsets)
716 void **itable = klass->idt->cls.itable;
717 jshort itable_pos = 0;
719 for (int i = 0; i < ifaces->count; i++)
721 jclass iface = ifaces->list[i];
722 itable_offsets[i] = itable_pos;
723 itable_pos = append_partial_itable (klass, iface, itable, itable_pos);
725 /* Create interface dispatch table for iface */
726 if (iface->idt == NULL)
729 = (_Jv_IDispatchTable *) _Jv_AllocRawObj (sizeof (_Jv_IDispatchTable));
731 // The first element of ioffsets is its length (itself included).
732 jshort *ioffsets = (jshort *) _Jv_AllocBytes (INITIAL_IOFFSETS_LEN
734 ioffsets[0] = INITIAL_IOFFSETS_LEN;
735 for (int i = 1; i < INITIAL_IOFFSETS_LEN; i++)
738 iface->idt->iface.ioffsets = ioffsets;
743 // Format method name for use in error messages.
745 _Jv_GetMethodString (jclass klass, _Jv_Method *meth,
748 using namespace java::lang;
749 StringBuffer *buf = new StringBuffer (klass->name->toString());
750 buf->append (jchar ('.'));
751 buf->append (meth->name->toString());
752 buf->append ((jchar) ' ');
753 buf->append (meth->signature->toString());
756 buf->append(JvNewStringLatin1(" in "));
757 buf->append(derived->name->toString());
759 return buf->toString();
763 _Jv_ThrowNoSuchMethodError ()
765 throw new java::lang::NoSuchMethodError;
769 // A function whose invocation is prepared using libffi. It gets called
770 // whenever a static method of a missing class is invoked. The data argument
771 // holds a reference to a String denoting the missing class.
772 // The prepared function call is stored in a class' atable.
774 _Jv_ThrowNoClassDefFoundErrorTrampoline(ffi_cif *,
779 throw new java::lang::NoClassDefFoundError(
780 _Jv_NewStringUtf8Const( (_Jv_Utf8Const *) data));
783 // A variant of the NoClassDefFoundError throwing method that can
784 // be used without libffi.
786 _Jv_ThrowNoClassDefFoundError()
788 throw new java::lang::NoClassDefFoundError();
792 // Throw a NoSuchFieldError. Called by compiler-generated code when
793 // an otable entry is zero. OTABLE_INDEX is the index in the caller's
794 // otable that refers to the missing field. This index may be used to
795 // print diagnostic information about the field.
797 _Jv_ThrowNoSuchFieldError (int /* otable_index */)
799 throw new java::lang::NoSuchFieldError;
802 // This is put in empty vtable slots.
804 _Jv_ThrowAbstractMethodError ()
806 throw new java::lang::AbstractMethodError();
809 // Each superinterface of a class (i.e. each interface that the class
810 // directly or indirectly implements) has a corresponding "Partial
811 // Interface Dispatch Table" whose size is (number of methods + 1) words.
812 // The first word is a pointer to the interface (i.e. the java.lang.Class
813 // instance for that interface). The remaining words are pointers to the
814 // actual methods that implement the methods declared in the interface,
815 // in order of declaration.
817 // Append partial interface dispatch table for "iface" to "itable", at
818 // position itable_pos.
819 // Returns the offset at which the next partial ITable should be appended.
821 _Jv_Linker::append_partial_itable (jclass klass, jclass iface,
822 void **itable, jshort pos)
824 using namespace java::lang::reflect;
826 itable[pos++] = (void *) iface;
829 for (int j=0; j < iface->method_count; j++)
832 for (jclass cl = klass; cl; cl = cl->getSuperclass())
834 meth = _Jv_GetMethodLocal (cl, iface->methods[j].name,
835 iface->methods[j].signature);
841 if (meth && (meth->name->first() == '<'))
843 // leave a placeholder in the itable for hidden init methods.
848 if ((meth->accflags & Modifier::STATIC) != 0)
849 throw new java::lang::IncompatibleClassChangeError
850 (_Jv_GetMethodString (klass, meth));
851 if ((meth->accflags & Modifier::PUBLIC) == 0)
852 throw new java::lang::IllegalAccessError
853 (_Jv_GetMethodString (klass, meth));
855 if ((meth->accflags & Modifier::ABSTRACT) != 0)
856 itable[pos] = (void *) &_Jv_ThrowAbstractMethodError;
858 itable[pos] = meth->ncode;
862 // The method doesn't exist in klass. Binary compatibility rules
863 // permit this, so we delay the error until runtime using a pointer
864 // to a method which throws an exception.
865 itable[pos] = (void *) _Jv_ThrowNoSuchMethodError;
873 static _Jv_Mutex_t iindex_mutex;
874 static bool iindex_mutex_initialized = false;
876 // We need to find the correct offset in the Class Interface Dispatch
877 // Table for a given interface. Once we have that, invoking an interface
878 // method just requires combining the Method's index in the interface
879 // (known at compile time) to get the correct method. Doing a type test
880 // (cast or instanceof) is the same problem: Once we have a possible Partial
881 // Interface Dispatch Table, we just compare the first element to see if it
882 // matches the desired interface. So how can we find the correct offset?
883 // Our solution is to keep a vector of candiate offsets in each interface
884 // (idt->iface.ioffsets), and in each class we have an index
885 // (idt->cls.iindex) used to select the correct offset from ioffsets.
887 // Calculate and return iindex for a new class.
888 // ifaces is a vector of num interfaces that the class implements.
889 // offsets[j] is the offset in the interface dispatch table for the
890 // interface corresponding to ifaces[j].
891 // May extend the interface ioffsets if required.
893 _Jv_Linker::find_iindex (jclass *ifaces, jshort *offsets, jshort num)
898 // Acquire a global lock to prevent itable corruption in case of multiple
899 // classes that implement an intersecting set of interfaces being linked
900 // simultaneously. We can assume that the mutex will be initialized
902 if (! iindex_mutex_initialized)
904 _Jv_MutexInit (&iindex_mutex);
905 iindex_mutex_initialized = true;
908 _Jv_MutexLock (&iindex_mutex);
910 for (i=1;; i++) /* each potential position in ioffsets */
912 for (j=0;; j++) /* each iface */
916 if (i >= ifaces[j]->idt->iface.ioffsets[0])
918 int ioffset = ifaces[j]->idt->iface.ioffsets[i];
919 /* We can potentially share this position with another class. */
920 if (ioffset >= 0 && ioffset != offsets[j])
921 break; /* Nope. Try next i. */
925 for (j = 0; j < num; j++)
927 int len = ifaces[j]->idt->iface.ioffsets[0];
931 int newlen = 2 * len;
934 jshort *old_ioffsets = ifaces[j]->idt->iface.ioffsets;
935 jshort *new_ioffsets = (jshort *) _Jv_AllocBytes (newlen
937 memcpy (&new_ioffsets[1], &old_ioffsets[1],
938 (len - 1) * sizeof (jshort));
939 new_ioffsets[0] = newlen;
942 new_ioffsets[len++] = -1;
944 ifaces[j]->idt->iface.ioffsets = new_ioffsets;
946 ifaces[j]->idt->iface.ioffsets[i] = offsets[j];
949 _Jv_MutexUnlock (&iindex_mutex);
956 // We use a structure of this type to store the closure that
957 // represents a missing method.
958 struct method_closure
960 // This field must come first, since the address of this field will
961 // be the same as the address of the overall structure. This is due
962 // to disabling interior pointers in the GC.
965 ffi_type *arg_types[1];
971 _Jv_Linker::create_error_method (_Jv_Utf8Const *class_name)
974 method_closure *closure
975 = (method_closure *) _Jv_AllocBytes(sizeof (method_closure));
977 closure->arg_types[0] = &ffi_type_void;
979 // Initializes the cif and the closure. If that worked the closure
980 // is returned and can be used as a function pointer in a class'
982 if (ffi_prep_cif (&closure->cif, FFI_DEFAULT_ABI, 1, &ffi_type_void,
983 closure->arg_types) == FFI_OK
984 && ffi_prep_closure (&closure->closure, &closure->cif,
985 _Jv_ThrowNoClassDefFoundErrorTrampoline,
986 class_name) == FFI_OK)
987 return &closure->closure;
990 java::lang::StringBuffer *buffer = new java::lang::StringBuffer();
991 buffer->append(JvNewStringLatin1("Error setting up FFI closure"
992 " for static method of"
993 " missing class: "));
994 buffer->append (_Jv_NewStringUtf8Const(class_name));
995 throw new java::lang::InternalError(buffer->toString());
998 // Codepath for platforms which do not support (or want) libffi.
999 // You have to accept that it is impossible to provide the name
1000 // of the missing class then.
1001 return (void *) _Jv_ThrowNoClassDefFoundError;
1005 // Functions for indirect dispatch (symbolic virtual binding) support.
1007 // There are three tables, atable otable and itable. atable is an
1008 // array of addresses, and otable is an array of offsets, and these
1009 // are used for static and virtual members respectively. itable is an
1010 // array of pairs {address, index} where each address is a pointer to
1013 // {a,o,i}table_syms is an array of _Jv_MethodSymbols. Each such
1014 // symbol is a tuple of {classname, member name, signature}.
1016 // Set this to true to enable debugging of indirect dispatch tables/linking.
1017 static bool debug_link = false;
1019 // link_symbol_table() scans these two arrays and fills in the
1020 // corresponding atable and otable with the addresses of static
1021 // members and the offsets of virtual members.
1023 // The offset (in bytes) for each resolved method or field is placed
1024 // at the corresponding position in the virtual method offset table
1027 // The same otable and atable may be shared by many classes.
1029 // This must be called while holding the class lock.
1032 _Jv_Linker::link_symbol_table (jclass klass)
1035 _Jv_MethodSymbol sym;
1036 if (klass->otable == NULL
1037 || klass->otable->state != 0)
1040 klass->otable->state = 1;
1043 fprintf (stderr, "Fixing up otable in %s:\n", klass->name->chars());
1045 (sym = klass->otable_syms[index]).class_name != NULL;
1048 jclass target_class = _Jv_FindClass (sym.class_name, klass->loader);
1049 _Jv_Method *meth = NULL;
1051 _Jv_Utf8Const *signature = sym.signature;
1053 if (target_class == NULL)
1054 throw new java::lang::NoClassDefFoundError
1055 (_Jv_NewStringUTF (sym.class_name->chars()));
1057 // We're looking for a field or a method, and we can tell
1058 // which is needed by looking at the signature.
1059 if (signature->first() == '(' && signature->len() >= 2)
1061 // Looks like someone is trying to invoke an interface method
1062 if (target_class->isInterface())
1064 using namespace java::lang;
1065 StringBuffer *sb = new StringBuffer();
1066 sb->append(JvNewStringLatin1("found interface "));
1067 sb->append(target_class->getName());
1068 sb->append(JvNewStringLatin1(" when searching for a class"));
1069 throw new VerifyError(sb->toString());
1072 // If the target class does not have a vtable_method_count yet,
1073 // then we can't tell the offsets for its methods, so we must lay
1075 wait_for_state(target_class, JV_STATE_PREPARED);
1077 meth = _Jv_LookupDeclaredMethod(target_class, sym.name,
1080 // Every class has a throwNoSuchMethodErrorIndex method that
1081 // it inherits from java.lang.Object. Find its vtable
1083 static int throwNoSuchMethodErrorIndex;
1084 if (throwNoSuchMethodErrorIndex == 0)
1087 = _Jv_makeUtf8Const ("throwNoSuchMethodError",
1088 strlen ("throwNoSuchMethodError"));
1090 = _Jv_LookupDeclaredMethod (&java::lang::Object::class$,
1091 name, gcj::void_signature);
1092 throwNoSuchMethodErrorIndex
1093 = _Jv_VTable::idx_to_offset (meth->index);
1096 // If we don't find a nonstatic method, insert the
1097 // vtable index of Object.throwNoSuchMethodError().
1098 // This defers the missing method error until an attempt
1099 // is made to execute it.
1104 offset = _Jv_VTable::idx_to_offset (meth->index);
1106 offset = throwNoSuchMethodErrorIndex;
1109 JvFail ("Bad method index");
1110 JvAssert (meth->index < target_class->vtable_method_count);
1112 klass->otable->offsets[index] = offset;
1116 fprintf (stderr, " offsets[%d] = %d (class %s@%p : %s(%s))\n",
1118 (int)klass->otable->offsets[index],
1119 (const char*)target_class->name->chars(),
1121 (const char*)sym.name->chars(),
1122 (const char*)signature->chars());
1128 wait_for_state(target_class, JV_STATE_PREPARED);
1130 _Jv_Field *the_field = NULL;
1133 the_field = find_field (klass, target_class, &found_class,
1134 sym.name, sym.signature);
1135 if ((the_field->flags & java::lang::reflect::Modifier::STATIC))
1136 throw new java::lang::IncompatibleClassChangeError;
1138 klass->otable->offsets[index] = the_field->u.boffset;
1140 catch (java::lang::NoSuchFieldError *err)
1142 klass->otable->offsets[index] = 0;
1148 if (klass->atable == NULL || klass->atable->state != 0)
1151 klass->atable->state = 1;
1154 (sym = klass->atable_syms[index]).class_name != NULL;
1157 jclass target_class =
1158 _Jv_FindClassNoException (sym.class_name, klass->loader);
1160 _Jv_Method *meth = NULL;
1161 _Jv_Utf8Const *signature = sym.signature;
1163 // ??? Setting this pointer to null will at least get us a
1164 // NullPointerException
1165 klass->atable->addresses[index] = NULL;
1167 // If the target class is missing we prepare a function call
1168 // that throws a NoClassDefFoundError and store the address of
1169 // that newly prepare method in the atable. The user can run
1170 // code in classes where the missing class is part of the
1171 // execution environment as long as it is never referenced.
1172 if (target_class == NULL)
1173 klass->atable->addresses[index] = create_error_method(sym.class_name);
1174 // We're looking for a static field or a static method, and we
1175 // can tell which is needed by looking at the signature.
1176 else if (signature->first() == '(' && signature->len() >= 2)
1178 // If the target class does not have a vtable_method_count yet,
1179 // then we can't tell the offsets for its methods, so we must lay
1181 wait_for_state (target_class, JV_STATE_PREPARED);
1183 // Interface methods cannot have bodies.
1184 if (target_class->isInterface())
1186 using namespace java::lang;
1187 StringBuffer *sb = new StringBuffer();
1188 sb->append(JvNewStringLatin1("class "));
1189 sb->append(target_class->getName());
1190 sb->append(JvNewStringLatin1(" is an interface: "
1192 throw new VerifyError(sb->toString());
1195 meth = _Jv_LookupDeclaredMethod(target_class, sym.name,
1200 if (meth->ncode) // Maybe abstract?
1202 klass->atable->addresses[index] = meth->ncode;
1204 fprintf (stderr, " addresses[%d] = %p (class %s@%p : %s(%s))\n",
1206 &klass->atable->addresses[index],
1207 (const char*)target_class->name->chars(),
1209 (const char*)sym.name->chars(),
1210 (const char*)signature->chars());
1214 klass->atable->addresses[index]
1215 = create_error_method(sym.class_name);
1220 // Try fields only if the target class exists.
1221 if ( target_class != NULL )
1223 wait_for_state(target_class, JV_STATE_PREPARED);
1225 _Jv_Field *the_field = find_field (klass, target_class, &found_class,
1226 sym.name, sym.signature);
1227 if ((the_field->flags & java::lang::reflect::Modifier::STATIC))
1228 klass->atable->addresses[index] = the_field->u.addr;
1230 throw new java::lang::IncompatibleClassChangeError;
1235 if (klass->itable == NULL
1236 || klass->itable->state != 0)
1239 klass->itable->state = 1;
1242 (sym = klass->itable_syms[index]).class_name != NULL;
1245 jclass target_class = _Jv_FindClass (sym.class_name, klass->loader);
1246 _Jv_Utf8Const *signature = sym.signature;
1251 wait_for_state(target_class, JV_STATE_LOADED);
1252 bool found = _Jv_getInterfaceMethod (target_class, cls, i,
1253 sym.name, sym.signature);
1257 klass->itable->addresses[index * 2] = cls;
1258 klass->itable->addresses[index * 2 + 1] = (void *)(unsigned long) i;
1261 fprintf (stderr, " interfaces[%d] = %p (interface %s@%p : %s(%s))\n",
1263 klass->itable->addresses[index * 2],
1264 (const char*)cls->name->chars(),
1266 (const char*)sym.name->chars(),
1267 (const char*)signature->chars());
1268 fprintf (stderr, " [%d] = offset %d\n",
1270 (int)(unsigned long)klass->itable->addresses[index * 2 + 1]);
1275 throw new java::lang::IncompatibleClassChangeError;
1280 // For each catch_record in the list of caught classes, fill in the
1283 _Jv_Linker::link_exception_table (jclass self)
1285 struct _Jv_CatchClass *catch_record = self->catch_classes;
1286 if (!catch_record || catch_record->classname)
1289 while (catch_record->classname)
1294 = _Jv_FindClass (catch_record->classname,
1295 self->getClassLoaderInternal ());
1296 *catch_record->address = target_class;
1298 catch (::java::lang::Throwable *t)
1300 // FIXME: We need to do something better here.
1301 *catch_record->address = 0;
1305 self->catch_classes->classname = (_Jv_Utf8Const *)-1;
1308 // Set itable method indexes for members of interface IFACE.
1310 _Jv_Linker::layout_interface_methods (jclass iface)
1312 if (! iface->isInterface())
1315 // itable indexes start at 1.
1316 // FIXME: Static initalizers currently get a NULL placeholder entry in the
1317 // itable so they are also assigned an index here.
1318 for (int i = 0; i < iface->method_count; i++)
1319 iface->methods[i].index = i + 1;
1322 // Prepare virtual method declarations in KLASS, and any superclasses
1323 // as required, by determining their vtable index, setting
1324 // method->index, and finally setting the class's vtable_method_count.
1325 // Must be called with the lock for KLASS held.
1327 _Jv_Linker::layout_vtable_methods (jclass klass)
1329 if (klass->vtable != NULL || klass->isInterface()
1330 || klass->vtable_method_count != -1)
1333 jclass superclass = klass->getSuperclass();
1335 if (superclass != NULL && superclass->vtable_method_count == -1)
1337 JvSynchronize sync (superclass);
1338 layout_vtable_methods (superclass);
1341 int index = (superclass == NULL ? 0 : superclass->vtable_method_count);
1343 for (int i = 0; i < klass->method_count; ++i)
1345 _Jv_Method *meth = &klass->methods[i];
1346 _Jv_Method *super_meth = NULL;
1348 if (! _Jv_isVirtualMethod (meth))
1351 if (superclass != NULL)
1354 super_meth = _Jv_LookupDeclaredMethod (superclass, meth->name,
1355 meth->signature, &declarer);
1356 // See if this method actually overrides the other method
1360 if (! _Jv_isVirtualMethod (super_meth)
1361 || ! _Jv_CheckAccess (klass, declarer,
1362 super_meth->accflags))
1364 else if ((super_meth->accflags
1365 & java::lang::reflect::Modifier::FINAL) != 0)
1367 using namespace java::lang;
1368 StringBuffer *sb = new StringBuffer();
1369 sb->append(JvNewStringLatin1("method "));
1370 sb->append(_Jv_GetMethodString(klass, meth));
1371 sb->append(JvNewStringLatin1(" overrides final method "));
1372 sb->append(_Jv_GetMethodString(declarer, super_meth));
1373 throw new VerifyError(sb->toString());
1379 meth->index = super_meth->index;
1381 meth->index = index++;
1384 klass->vtable_method_count = index;
1387 // Set entries in VTABLE for virtual methods declared in KLASS.
1389 _Jv_Linker::set_vtable_entries (jclass klass, _Jv_VTable *vtable)
1391 for (int i = klass->method_count - 1; i >= 0; i--)
1393 using namespace java::lang::reflect;
1395 _Jv_Method *meth = &klass->methods[i];
1396 if (meth->index == (_Jv_ushort) -1)
1398 if ((meth->accflags & Modifier::ABSTRACT))
1399 // FIXME: it might be nice to have a libffi trampoline here,
1400 // so we could pass in the method name and other information.
1401 vtable->set_method(meth->index,
1402 (void *) &_Jv_ThrowAbstractMethodError);
1404 vtable->set_method(meth->index, meth->ncode);
1408 // Allocate and lay out the virtual method table for KLASS. This will
1409 // also cause vtables to be generated for any non-abstract
1410 // superclasses, and virtual method layout to occur for any abstract
1411 // superclasses. Must be called with monitor lock for KLASS held.
1413 _Jv_Linker::make_vtable (jclass klass)
1415 using namespace java::lang::reflect;
1417 // If the vtable exists, or for interface classes, do nothing. All
1418 // other classes, including abstract classes, need a vtable.
1419 if (klass->vtable != NULL || klass->isInterface())
1422 // Ensure all the `ncode' entries are set.
1423 klass->engine->create_ncode(klass);
1425 // Class must be laid out before we can create a vtable.
1426 if (klass->vtable_method_count == -1)
1427 layout_vtable_methods (klass);
1429 // Allocate the new vtable.
1430 _Jv_VTable *vtable = _Jv_VTable::new_vtable (klass->vtable_method_count);
1431 klass->vtable = vtable;
1433 // Copy the vtable of the closest superclass.
1434 jclass superclass = klass->superclass;
1436 JvSynchronize sync (superclass);
1437 make_vtable (superclass);
1439 for (int i = 0; i < superclass->vtable_method_count; ++i)
1440 vtable->set_method (i, superclass->vtable->get_method (i));
1442 // Set the class pointer and GC descriptor.
1443 vtable->clas = klass;
1444 vtable->gc_descr = _Jv_BuildGCDescr (klass);
1446 // For each virtual declared in klass, set new vtable entry or
1447 // override an old one.
1448 set_vtable_entries (klass, vtable);
1450 // Note that we don't check for abstract methods here. We used to,
1451 // but there is a JVMS clarification that indicates that a check
1452 // here would be too eager. And, a simple test case confirms this.
1455 // Lay out the class, allocating space for static fields and computing
1456 // offsets of instance fields. The class lock must be held by the
1459 _Jv_Linker::ensure_fields_laid_out (jclass klass)
1461 if (klass->size_in_bytes != -1)
1464 // Compute the alignment for this type by searching through the
1465 // superclasses and finding the maximum required alignment. We
1466 // could consider caching this in the Class.
1467 int max_align = __alignof__ (java::lang::Object);
1468 jclass super = klass->getSuperclass();
1469 while (super != NULL)
1471 // Ensure that our super has its super installed before
1473 wait_for_state(super, JV_STATE_LOADING);
1474 ensure_fields_laid_out(super);
1475 int num = JvNumInstanceFields (super);
1476 _Jv_Field *field = JvGetFirstInstanceField (super);
1479 int field_align = get_alignment_from_class (field->type);
1480 if (field_align > max_align)
1481 max_align = field_align;
1485 super = super->getSuperclass();
1489 // This is the size of the 'static' non-reference fields.
1490 int non_reference_size = 0;
1491 // This is the size of the 'static' reference fields. We count
1492 // these separately to make it simpler for the GC to scan them.
1493 int reference_size = 0;
1495 // Although java.lang.Object is never interpreted, an interface can
1496 // have a null superclass. Note that we have to lay out an
1497 // interface because it might have static fields.
1498 if (klass->superclass)
1499 instance_size = klass->superclass->size();
1501 instance_size = java::lang::Object::class$.size();
1503 for (int i = 0; i < klass->field_count; i++)
1508 _Jv_Field *field = &klass->fields[i];
1510 if (! field->isRef ())
1512 // It is safe to resolve the field here, since it's a
1513 // primitive class, which does not cause loading to happen.
1514 resolve_field (field, klass->loader);
1516 field_size = field->type->size ();
1517 field_align = get_alignment_from_class (field->type);
1521 field_size = sizeof (jobject);
1522 field_align = __alignof__ (jobject);
1525 field->bsize = field_size;
1527 if ((field->flags & java::lang::reflect::Modifier::STATIC))
1529 if (field->u.addr == NULL)
1531 // This computes an offset into a region we'll allocate
1532 // shortly, and then adds this offset to the start
1536 reference_size = ROUND (reference_size, field_align);
1537 field->u.boffset = reference_size;
1538 reference_size += field_size;
1542 non_reference_size = ROUND (non_reference_size, field_align);
1543 field->u.boffset = non_reference_size;
1544 non_reference_size += field_size;
1550 instance_size = ROUND (instance_size, field_align);
1551 field->u.boffset = instance_size;
1552 instance_size += field_size;
1553 if (field_align > max_align)
1554 max_align = field_align;
1558 if (reference_size != 0 || non_reference_size != 0)
1559 klass->engine->allocate_static_fields (klass, reference_size,
1560 non_reference_size);
1562 // Set the instance size for the class. Note that first we round it
1563 // to the alignment required for this object; this keeps us in sync
1564 // with our current ABI.
1565 instance_size = ROUND (instance_size, max_align);
1566 klass->size_in_bytes = instance_size;
1569 // This takes the class to state JV_STATE_LINKED. The class lock must
1570 // be held when calling this.
1572 _Jv_Linker::ensure_class_linked (jclass klass)
1574 if (klass->state >= JV_STATE_LINKED)
1577 int state = klass->state;
1580 // Short-circuit, so that mutually dependent classes are ok.
1581 klass->state = JV_STATE_LINKED;
1583 _Jv_Constants *pool = &klass->constants;
1585 // Compiled classes require that their class constants be
1586 // resolved here. However, interpreted classes need their
1587 // constants to be resolved lazily. If we resolve an
1588 // interpreted class' constants eagerly, we can end up with
1589 // spurious IllegalAccessErrors when the constant pool contains
1590 // a reference to a class we can't access. This can validly
1591 // occur in an obscure case involving the InnerClasses
1593 if (! _Jv_IsInterpretedClass (klass))
1595 // Resolve class constants first, since other constant pool
1596 // entries may rely on these.
1597 for (int index = 1; index < pool->size; ++index)
1599 if (pool->tags[index] == JV_CONSTANT_Class)
1600 // Lazily resolve the entries.
1601 resolve_pool_entry (klass, index, true);
1605 #if 0 // Should be redundant now
1606 // If superclass looks like a constant pool entry,
1608 if ((uaddr) klass->superclass < (uaddr) pool->size)
1609 klass->superclass = pool->data[(uaddr) klass->superclass].clazz;
1611 // Likewise for interfaces.
1612 for (int i = 0; i < klass->interface_count; i++)
1614 if ((uaddr) klass->interfaces[i] < (uaddr) pool->size)
1615 klass->interfaces[i]
1616 = pool->data[(uaddr) klass->interfaces[i]].clazz;
1620 // Resolve the remaining constant pool entries.
1621 for (int index = 1; index < pool->size; ++index)
1623 if (pool->tags[index] == JV_CONSTANT_String)
1627 str = _Jv_NewStringUtf8Const (pool->data[index].utf8);
1628 pool->data[index].o = str;
1629 pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
1633 if (klass->engine->need_resolve_string_fields())
1635 jfieldID f = JvGetFirstStaticField (klass);
1636 for (int n = JvNumStaticFields (klass); n > 0; --n)
1638 int mod = f->getModifiers ();
1639 // If we have a static String field with a non-null initial
1640 // value, we know it points to a Utf8Const.
1642 // Finds out whether we have to initialize a String without the
1643 // need to resolve the field.
1644 if ((f->isResolved()
1645 ? (f->type == &java::lang::String::class$)
1646 : _Jv_equalUtf8Classnames((_Jv_Utf8Const *) f->type,
1647 java::lang::String::class$.name))
1648 && (mod & java::lang::reflect::Modifier::STATIC) != 0)
1650 jstring *strp = (jstring *) f->u.addr;
1652 *strp = _Jv_NewStringUtf8Const ((_Jv_Utf8Const *) *strp);
1654 f = f->getNextField ();
1658 klass->notifyAll ();
1660 _Jv_PushClass (klass);
1662 catch (java::lang::Throwable *t)
1664 klass->state = state;
1669 // This ensures that symbolic superclass and superinterface references
1670 // are resolved for the indicated class. This must be called with the
1673 _Jv_Linker::ensure_supers_installed (jclass klass)
1675 resolve_class_ref (klass, &klass->superclass);
1676 // An interface won't have a superclass.
1677 if (klass->superclass)
1678 wait_for_state (klass->superclass, JV_STATE_LOADING);
1680 for (int i = 0; i < klass->interface_count; ++i)
1682 resolve_class_ref (klass, &klass->interfaces[i]);
1683 wait_for_state (klass->interfaces[i], JV_STATE_LOADING);
1687 // This adds missing `Miranda methods' to a class.
1689 _Jv_Linker::add_miranda_methods (jclass base, jclass iface_class)
1691 // Note that at this point, all our supers, and the supers of all
1692 // our superclasses and superinterfaces, will have been installed.
1694 for (int i = 0; i < iface_class->interface_count; ++i)
1696 jclass interface = iface_class->interfaces[i];
1698 for (int j = 0; j < interface->method_count; ++j)
1700 _Jv_Method *meth = &interface->methods[j];
1701 // Don't bother with <clinit>.
1702 if (meth->name->first() == '<')
1704 _Jv_Method *new_meth = _Jv_LookupDeclaredMethod (base, meth->name,
1708 // We assume that such methods are very unlikely, so we
1709 // just reallocate the method array each time one is
1710 // found. This greatly simplifies the searching --
1711 // otherwise we have to make sure that each such method
1712 // found is really unique among all superinterfaces.
1713 int new_count = base->method_count + 1;
1715 = (_Jv_Method *) _Jv_AllocRawObj (sizeof (_Jv_Method)
1717 memcpy (new_m, base->methods,
1718 sizeof (_Jv_Method) * base->method_count);
1721 new_m[base->method_count] = *meth;
1722 new_m[base->method_count].index = (_Jv_ushort) -1;
1723 new_m[base->method_count].accflags
1724 |= java::lang::reflect::Modifier::INVISIBLE;
1726 base->methods = new_m;
1727 base->method_count = new_count;
1731 wait_for_state (interface, JV_STATE_LOADED);
1732 add_miranda_methods (base, interface);
1736 // This ensures that the class' method table is "complete". This must
1737 // be called with the class lock held.
1739 _Jv_Linker::ensure_method_table_complete (jclass klass)
1741 if (klass->vtable != NULL)
1744 // We need our superclass to have its own Miranda methods installed.
1745 if (! klass->isInterface())
1746 wait_for_state (klass->getSuperclass (), JV_STATE_LOADED);
1748 // A class might have so-called "Miranda methods". This is a method
1749 // that is declared in an interface and not re-declared in an
1750 // abstract class. Some compilers don't emit declarations for such
1751 // methods in the class; this will give us problems since we expect
1752 // a declaration for any method requiring a vtable entry. We handle
1753 // this here by searching for such methods and constructing new
1754 // internal declarations for them. Note that we do this
1755 // unconditionally, and not just for abstract classes, to correctly
1756 // account for cases where a class is modified to be concrete and
1757 // still incorrectly inherits an abstract method.
1758 int pre_count = klass->method_count;
1759 add_miranda_methods (klass, klass);
1761 // Let the execution engine know that we've added methods.
1762 if (klass->method_count != pre_count)
1763 klass->engine->post_miranda_hook(klass);
1766 // Verify a class. Must be called with class lock held.
1768 _Jv_Linker::verify_class (jclass klass)
1770 klass->engine->verify(klass);
1773 // Check the assertions contained in the type assertion table for KLASS.
1774 // This is the equivilent of bytecode verification for native, BC-ABI code.
1776 _Jv_Linker::verify_type_assertions (jclass klass)
1779 fprintf (stderr, "Evaluating type assertions for %s:\n",
1780 klass->name->chars());
1782 if (klass->assertion_table == NULL)
1785 for (int i = 0;; i++)
1787 int assertion_code = klass->assertion_table[i].assertion_code;
1788 _Jv_Utf8Const *op1 = klass->assertion_table[i].op1;
1789 _Jv_Utf8Const *op2 = klass->assertion_table[i].op2;
1791 if (assertion_code == JV_ASSERT_END_OF_TABLE)
1793 else if (assertion_code == JV_ASSERT_TYPES_COMPATIBLE)
1797 fprintf (stderr, " code=%i, operand A=%s B=%s\n",
1798 assertion_code, op1->chars(), op2->chars());
1801 // The operands are class signatures. op1 is the source,
1802 // op2 is the target.
1803 jclass cl1 = _Jv_FindClassFromSignature (op1->chars(),
1804 klass->getClassLoaderInternal());
1805 jclass cl2 = _Jv_FindClassFromSignature (op2->chars(),
1806 klass->getClassLoaderInternal());
1808 // If the class doesn't exist, ignore the assertion. An exception
1809 // will be thrown later if an attempt is made to actually
1810 // instantiate the class.
1811 if (cl1 == NULL || cl2 == NULL)
1814 if (! _Jv_IsAssignableFromSlow (cl1, cl2))
1816 jstring s = JvNewStringUTF ("Incompatible types: In class ");
1817 s = s->concat (klass->getName());
1818 s = s->concat (JvNewStringUTF (": "));
1819 s = s->concat (cl1->getName());
1820 s = s->concat (JvNewStringUTF (" is not assignable to "));
1821 s = s->concat (cl2->getName());
1822 throw new java::lang::VerifyError (s);
1825 else if (assertion_code == JV_ASSERT_IS_INSTANTIABLE)
1827 // TODO: Implement this.
1829 // Unknown assertion codes are ignored, for forwards-compatibility.
1834 _Jv_Linker::print_class_loaded (jclass klass)
1836 char *codesource = NULL;
1837 if (klass->protectionDomain != NULL)
1839 java::security::CodeSource *cs
1840 = klass->protectionDomain->getCodeSource();
1843 jstring css = cs->toString();
1844 int len = JvGetStringUTFLength(css);
1845 codesource = (char *) _Jv_AllocBytes(len + 1);
1846 JvGetStringUTFRegion(css, 0, css->length(), codesource);
1847 codesource[len] = '\0';
1850 if (codesource == NULL)
1851 codesource = (char *) "<no code source>";
1854 if (_Jv_IsInterpretedClass (klass))
1856 else if (_Jv_IsBinaryCompatibilityABI (klass))
1857 abi = "BC-compiled";
1859 abi = "pre-compiled";
1861 fprintf (stderr, "[Loaded (%s) %s from %s]\n", abi, klass->name->chars(),
1865 // FIXME: mention invariants and stuff.
1867 _Jv_Linker::wait_for_state (jclass klass, int state)
1869 if (klass->state >= state)
1872 JvSynchronize sync (klass);
1874 // This is similar to the strategy for class initialization. If we
1875 // already hold the lock, just leave.
1876 java::lang::Thread *self = java::lang::Thread::currentThread();
1877 while (klass->state <= state
1879 && klass->thread != self)
1882 java::lang::Thread *save = klass->thread;
1883 klass->thread = self;
1885 // Print some debugging info if requested. Interpreted classes are
1886 // handled in defineclass, so we only need to handle the two
1887 // pre-compiled cases here.
1888 if (gcj::verbose_class_flag
1889 && (klass->state == JV_STATE_COMPILED
1890 || klass->state == JV_STATE_PRELOADING)
1891 && ! _Jv_IsInterpretedClass (klass))
1892 print_class_loaded (klass);
1896 if (state >= JV_STATE_LOADING && klass->state < JV_STATE_LOADING)
1898 ensure_supers_installed (klass);
1899 klass->set_state(JV_STATE_LOADING);
1902 if (state >= JV_STATE_LOADED && klass->state < JV_STATE_LOADED)
1904 ensure_method_table_complete (klass);
1905 klass->set_state(JV_STATE_LOADED);
1908 if (state >= JV_STATE_PREPARED && klass->state < JV_STATE_PREPARED)
1910 ensure_fields_laid_out (klass);
1911 make_vtable (klass);
1912 layout_interface_methods (klass);
1913 prepare_constant_time_tables (klass);
1914 klass->set_state(JV_STATE_PREPARED);
1917 if (state >= JV_STATE_LINKED && klass->state < JV_STATE_LINKED)
1919 if (gcj::verifyClasses)
1920 verify_class (klass);
1922 ensure_class_linked (klass);
1923 link_exception_table (klass);
1924 link_symbol_table (klass);
1925 klass->set_state(JV_STATE_LINKED);
1928 catch (java::lang::Throwable *exc)
1930 klass->thread = save;
1931 klass->set_state(JV_STATE_ERROR);
1935 klass->thread = save;
1937 if (klass->state == JV_STATE_ERROR)
1938 throw new java::lang::LinkageError;