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jdk-24/hotspot/src/share/vm/oops/klassVtable.cpp

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2007-12-01 00:00:00 +00:00
/*
* Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
#include "incls/_precompiled.incl"
#include "incls/_klassVtable.cpp.incl"
inline instanceKlass* klassVtable::ik() const {
Klass* k = _klass()->klass_part();
assert(k->oop_is_instance(), "not an instanceKlass");
return (instanceKlass*)k;
}
// this function computes the vtable size (including the size needed for miranda
// methods) and the number of miranda methods in this class
// Note on Miranda methods: Let's say there is a class C that implements
// interface I. Let's say there is a method m in I that neither C nor any
// of its super classes implement (i.e there is no method of any access, with
// the same name and signature as m), then m is a Miranda method which is
// entered as a public abstract method in C's vtable. From then on it should
// treated as any other public method in C for method over-ride purposes.
void klassVtable::compute_vtable_size_and_num_mirandas(int &vtable_length,
int &num_miranda_methods,
klassOop super,
objArrayOop methods,
AccessFlags class_flags,
oop classloader,
symbolOop classname,
objArrayOop local_interfaces
) {
No_Safepoint_Verifier nsv;
// set up default result values
vtable_length = 0;
num_miranda_methods = 0;
// start off with super's vtable length
instanceKlass* sk = (instanceKlass*)super->klass_part();
vtable_length = super == NULL ? 0 : sk->vtable_length();
// go thru each method in the methods table to see if it needs a new entry
int len = methods->length();
for (int i = 0; i < len; i++) {
assert(methods->obj_at(i)->is_method(), "must be a methodOop");
methodOop m = methodOop(methods->obj_at(i));
if (needs_new_vtable_entry(m, super, classloader, classname, class_flags)) {
vtable_length += vtableEntry::size(); // we need a new entry
}
}
// compute the number of mirandas methods that must be added to the end
num_miranda_methods = get_num_mirandas(super, methods, local_interfaces);
vtable_length += (num_miranda_methods * vtableEntry::size());
if (Universe::is_bootstrapping() && vtable_length == 0) {
// array classes don't have their superclass set correctly during
// bootstrapping
vtable_length = Universe::base_vtable_size();
}
if (super == NULL && !Universe::is_bootstrapping() &&
vtable_length != Universe::base_vtable_size()) {
// Someone is attempting to redefine java.lang.Object incorrectly. The
// only way this should happen is from
// SystemDictionary::resolve_from_stream(), which will detect this later
// and throw a security exception. So don't assert here to let
// the exception occur.
vtable_length = Universe::base_vtable_size();
}
assert(super != NULL || vtable_length == Universe::base_vtable_size(),
"bad vtable size for class Object");
assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
}
int klassVtable::index_of(methodOop m, int len) const {
assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
return m->vtable_index();
}
int klassVtable::initialize_from_super(KlassHandle super) {
if (super.is_null()) {
return 0;
} else {
// copy methods from superKlass
// can't inherit from array class, so must be instanceKlass
assert(super->oop_is_instance(), "must be instance klass");
instanceKlass* sk = (instanceKlass*)super()->klass_part();
klassVtable* superVtable = sk->vtable();
assert(superVtable->length() <= _length, "vtable too short");
#ifdef ASSERT
superVtable->verify(tty, true);
#endif
superVtable->copy_vtable_to(table());
#ifndef PRODUCT
if (PrintVtables && Verbose) {
tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
}
#endif
return superVtable->length();
}
}
// Revised lookup semantics introduced 1.3 (Kestral beta)
void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
// Note: Arrays can have intermediate array supers. Use java_super to skip them.
KlassHandle super (THREAD, klass()->java_super());
int nofNewEntries = 0;
if (PrintVtables && !klass()->oop_is_array()) {
ResourceMark rm(THREAD);
tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
}
#ifdef ASSERT
oop* end_of_obj = (oop*)_klass() + _klass()->size();
oop* end_of_vtable = (oop*)&table()[_length];
assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
#endif
if (Universe::is_bootstrapping()) {
// just clear everything
for (int i = 0; i < _length; i++) table()[i].clear();
return;
}
int super_vtable_len = initialize_from_super(super);
if (klass()->oop_is_array()) {
assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
} else {
assert(_klass->oop_is_instance(), "must be instanceKlass");
objArrayHandle methods(THREAD, ik()->methods());
int len = methods()->length();
int initialized = super_vtable_len;
// update_super_vtable can stop for gc - ensure using handles
for (int i = 0; i < len; i++) {
HandleMark hm(THREAD);
assert(methods()->obj_at(i)->is_method(), "must be a methodOop");
methodHandle mh(THREAD, (methodOop)methods()->obj_at(i));
bool needs_new_entry = update_super_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
if (needs_new_entry) {
put_method_at(mh(), initialized);
mh()->set_vtable_index(initialized); // set primary vtable index
initialized++;
}
}
// add miranda methods; it will also update the value of initialized
fill_in_mirandas(initialized);
// In class hierachieswhere the accesibility is not increasing (i.e., going from private ->
// package_private -> publicprotected), the vtable might actually be smaller than our initial
// calculation.
assert(initialized <= _length, "vtable initialization failed");
for(;initialized < _length; initialized++) {
put_method_at(NULL, initialized);
}
NOT_PRODUCT(verify(tty, true));
}
}
// Interates through the vtables to find the broadest access level. This
// will always be monotomic for valid Java programs - but not neccesarily
// for incompatible class files.
klassVtable::AccessType klassVtable::vtable_accessibility_at(int i) {
// This vtable is not implementing the specific method
if (i >= length()) return acc_private;
// Compute AccessType for current method. public or protected we are done.
methodOop m = method_at(i);
if (m->is_protected() || m->is_public()) return acc_publicprotected;
AccessType acc = m->is_package_private() ? acc_package_private : acc_private;
// Compute AccessType for method in super classes
klassOop super = klass()->super();
AccessType super_acc = (super != NULL) ? instanceKlass::cast(klass()->super())->vtable()->vtable_accessibility_at(i)
: acc_private;
// Merge
return (AccessType)MAX2((int)acc, (int)super_acc);
}
// Update child's copy of super vtable for overrides
// OR return true if a new vtable entry is required
// Only called for instanceKlass's, i.e. not for arrays
// If that changed, could not use _klass as handle for klass
bool klassVtable::update_super_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS) {
ResourceMark rm;
bool allocate_new = true;
assert(klass->oop_is_instance(), "must be instanceKlass");
// Initialize the method's vtable index to "nonvirtual".
// If we allocate a vtable entry, we will update it to a non-negative number.
target_method()->set_vtable_index(methodOopDesc::nonvirtual_vtable_index);
// Static and <init> methods are never in
if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
return false;
}
if (klass->is_final() || target_method()->is_final()) {
// a final method never needs a new entry; final methods can be statically
// resolved and they have to be present in the vtable only if they override
// a super's method, in which case they re-use its entry
allocate_new = false;
}
// we need a new entry if there is no superclass
if (klass->super() == NULL) {
return allocate_new;
}
// private methods always have a new entry in the vtable
if (target_method()->is_private()) {
return allocate_new;
}
// search through the vtable and update overridden entries
// Since check_signature_loaders acquires SystemDictionary_lock
// which can block for gc, once we are in this loop, use handles, not
// unhandled oops unless they are reinitialized for each loop
// handles for name, signature, klass, target_method
// not for match_method, holder
symbolHandle name(THREAD,target_method()->name());
symbolHandle signature(THREAD,target_method()->signature());
for(int i = 0; i < super_vtable_len; i++) {
methodOop match_method = method_at(i);
// Check if method name matches
if (match_method->name() == name() && match_method->signature() == signature()) {
instanceKlass* holder = (THREAD, instanceKlass::cast(match_method->method_holder()));
// Check if the match_method is accessable from current class
bool same_package_init = false;
bool same_package_flag = false;
bool simple_match = match_method->is_public() || match_method->is_protected();
if (!simple_match) {
same_package_init = true;
same_package_flag = holder->is_same_class_package(_klass->class_loader(), _klass->name());
simple_match = match_method->is_package_private() && same_package_flag;
}
// match_method is the superclass' method. Note we can't override
// and shouldn't access superclass' ACC_PRIVATE methods
// (although they have been copied into our vtable)
// A simple form of this statement is:
// if ( (match_method->is_public() || match_method->is_protected()) ||
// (match_method->is_package_private() && holder->is_same_class_package(klass->class_loader(), klass->name()))) {
//
// The complexity is introduced it avoid recomputing 'is_same_class_package' which is expensive.
if (simple_match) {
// Check if target_method and match_method has same level of accessibility. The accesibility of the
// match method is the "most-general" visibility of all entries at it's particular vtable index for
// all superclasses. This check must be done before we override the current entry in the vtable.
AccessType at = vtable_accessibility_at(i);
bool same_access = false;
if ( (at == acc_publicprotected && (target_method()->is_public() || target_method()->is_protected())
|| (at == acc_package_private && (target_method()->is_package_private() &&
(( same_package_init && same_package_flag) ||
(!same_package_init && holder->is_same_class_package(_klass->class_loader(), _klass->name()))))))) {
same_access = true;
}
if (checkconstraints) {
// Override vtable entry if passes loader constraint check
// if loader constraint checking requested
// No need to visit his super, since he and his super
// have already made any needed loader constraints.
// Since loader constraints are transitive, it is enough
// to link to the first super, and we get all the others.
symbolHandle signature(THREAD, target_method()->signature());
Handle this_loader(THREAD, _klass->class_loader());
instanceKlassHandle super_klass(THREAD, _klass->super());
Handle super_loader(THREAD, super_klass->class_loader());
if (this_loader() != super_loader()) {
ResourceMark rm(THREAD);
char* failed_type_name =
SystemDictionary::check_signature_loaders(signature, this_loader,
super_loader, true,
CHECK_(false));
if (failed_type_name != NULL) {
const char* msg = "loader constraint violation: when resolving "
"overridden method \"%s\" the class loader (instance"
" of %s) of the current class, %s, and its superclass loader "
"(instance of %s), have different Class objects for the type "
"%s used in the signature";
char* sig = target_method()->name_and_sig_as_C_string();
const char* loader1 = SystemDictionary::loader_name(this_loader());
char* current = _klass->name()->as_C_string();
const char* loader2 = SystemDictionary::loader_name(super_loader());
size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
strlen(current) + strlen(loader2) + strlen(failed_type_name);
char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
failed_type_name);
THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
}
}
}
put_method_at(target_method(), i);
if (same_access) {
// target and match has same accessiblity - share entry
allocate_new = false;
target_method()->set_vtable_index(i);
#ifndef PRODUCT
if (PrintVtables && Verbose) {
AccessType targetacc;
if (target_method()->is_protected() ||
target_method()->is_public()) {
targetacc = acc_publicprotected;
} else {
targetacc = target_method()->is_package_private() ? acc_package_private : acc_private;
}
tty->print_cr("overriding with %s::%s index %d, original flags: %x overriders flags: %x",
_klass->internal_name(), (target_method() != NULL) ?
target_method()->name()->as_C_string() : "<NULL>", i,
at, targetacc);
}
#endif /*PRODUCT*/
} else {
#ifndef PRODUCT
if (PrintVtables && Verbose) {
AccessType targetacc;
if (target_method()->is_protected() ||
target_method()->is_public()) {
targetacc = acc_publicprotected;
} else {
targetacc = target_method()->is_package_private() ? acc_package_private : acc_private;
}
tty->print_cr("override %s %s::%s at index %d, original flags: %x overriders flags: %x",
allocate_new ? "+ new" : "only",
_klass->internal_name(), (target_method() != NULL) ?
target_method()->name()->as_C_string() : "<NULL>", i,
at, targetacc);
}
#endif /*PRODUCT*/
}
}
}
}
return allocate_new;
}
void klassVtable::put_method_at(methodOop m, int index) {
assert(m->is_oop_or_null(), "Not an oop or null");
#ifndef PRODUCT
if (PrintVtables && Verbose) {
tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
(m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
}
assert(unchecked_method_at(index)->is_oop_or_null(), "Not an oop or null");
#endif
table()[index].set(m);
}
// Find out if a method "m" with superclass "super", loader "classloader" and
// name "classname" needs a new vtable entry. Let P be a class package defined
// by "classloader" and "classname".
// NOTE: The logic used here is very similar to the one used for computing
// the vtables indices for a method. We cannot directly use that function because,
// when the Universe is boostrapping, a super's vtable might not be initialized.
bool klassVtable::needs_new_vtable_entry(methodOop target_method,
klassOop super,
oop classloader,
symbolOop classname,
AccessFlags class_flags) {
if ((class_flags.is_final() || target_method->is_final()) ||
// a final method never needs a new entry; final methods can be statically
// resolved and they have to be present in the vtable only if they override
// a super's method, in which case they re-use its entry
(target_method->is_static()) ||
// static methods don't need to be in vtable
(target_method->name() == vmSymbols::object_initializer_name())
// <init> is never called dynamically-bound
) {
return false;
}
// we need a new entry if there is no superclass
if (super == NULL) {
return true;
}
// private methods always have a new entry in the vtable
if (target_method->is_private()) {
return true;
}
// search through the super class hierarchy to see if we need
// a new entry
symbolOop name = target_method->name();
symbolOop signature = target_method->signature();
klassOop k = super;
methodOop match_method = NULL;
instanceKlass *holder = NULL;
while (k != NULL) {
// lookup through the hierarchy for a method with matching name and sign.
match_method = instanceKlass::cast(k)->lookup_method(name, signature);
if (match_method == NULL) {
break; // we still have to search for a matching miranda method
}
// get the class holding the matching method
holder = instanceKlass::cast(match_method->method_holder());
if (!match_method->is_static()) { // we want only instance method matches
if ((target_method->is_public() || target_method->is_protected()) &&
(match_method->is_public() || match_method->is_protected())) {
// target and match are public/protected; we do not need a new entry
return false;
}
if (target_method->is_package_private() &&
match_method->is_package_private() &&
holder->is_same_class_package(classloader, classname)) {
// target and match are P private; we do not need a new entry
return false;
}
}
k = holder->super(); // haven't found a match yet; continue to look
}
// if the target method is public or protected it may have a matching
// miranda method in the super, whose entry it should re-use.
if (target_method->is_public() || target_method->is_protected()) {
instanceKlass *sk = instanceKlass::cast(super);
if (sk->has_miranda_methods()) {
if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
return false; // found a matching miranda; we do not need a new entry
}
}
}
return true; // found no match; we need a new entry
}
// Support for miranda methods
// get the vtable index of a miranda method with matching "name" and "signature"
int klassVtable::index_of_miranda(symbolOop name, symbolOop signature) {
// search from the bottom, might be faster
for (int i = (length() - 1); i >= 0; i--) {
methodOop m = table()[i].method();
if (is_miranda_entry_at(i) &&
m->name() == name && m->signature() == signature) {
return i;
}
}
return methodOopDesc::invalid_vtable_index;
}
// check if an entry is miranda
bool klassVtable::is_miranda_entry_at(int i) {
methodOop m = method_at(i);
klassOop method_holder = m->method_holder();
instanceKlass *mhk = instanceKlass::cast(method_holder);
// miranda methods are interface methods in a class's vtable
if (mhk->is_interface()) {
assert(m->is_public() && m->is_abstract(), "should be public and abstract");
assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
return true;
}
return false;
}
// check if a method is a miranda method, given a class's methods table and it's super
// the caller must make sure that the method belongs to an interface implemented by the class
bool klassVtable::is_miranda(methodOop m, objArrayOop class_methods, klassOop super) {
symbolOop name = m->name();
symbolOop signature = m->signature();
if (instanceKlass::find_method(class_methods, name, signature) == NULL) {
// did not find it in the method table of the current class
if (super == NULL) {
// super doesn't exist
return true;
} else {
if (instanceKlass::cast(super)->lookup_method(name, signature) == NULL) {
// super class hierarchy does not implement it
return true;
}
}
}
return false;
}
void klassVtable::add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas,
objArrayOop current_interface_methods,
objArrayOop class_methods,
klassOop super) {
// iterate thru the current interface's method to see if it a miranda
int num_methods = current_interface_methods->length();
for (int i = 0; i < num_methods; i++) {
methodOop im = methodOop(current_interface_methods->obj_at(i));
bool is_duplicate = false;
int num_of_current_mirandas = list_of_current_mirandas->length();
// check for duplicate mirandas in different interfaces we implement
for (int j = 0; j < num_of_current_mirandas; j++) {
methodOop miranda = list_of_current_mirandas->at(j);
if ((im->name() == miranda->name()) &&
(im->signature() == miranda->signature())) {
is_duplicate = true;
break;
}
}
if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
if (is_miranda(im, class_methods, super)) { // is it a miranda at all?
instanceKlass *sk = instanceKlass::cast(super);
// check if it is a duplicate of a super's miranda
if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
list_of_current_mirandas->append(im);
}
}
}
}
}
void klassVtable::get_mirandas(GrowableArray<methodOop>* mirandas,
klassOop super, objArrayOop class_methods,
objArrayOop local_interfaces) {
assert((mirandas->length() == 0) , "current mirandas must be 0");
// iterate thru the local interfaces looking for a miranda
int num_local_ifs = local_interfaces->length();
for (int i = 0; i < num_local_ifs; i++) {
instanceKlass *ik = instanceKlass::cast(klassOop(local_interfaces->obj_at(i)));
add_new_mirandas_to_list(mirandas, ik->methods(), class_methods, super);
// iterate thru each local's super interfaces
objArrayOop super_ifs = ik->transitive_interfaces();
int num_super_ifs = super_ifs->length();
for (int j = 0; j < num_super_ifs; j++) {
instanceKlass *sik = instanceKlass::cast(klassOop(super_ifs->obj_at(j)));
add_new_mirandas_to_list(mirandas, sik->methods(), class_methods, super);
}
}
}
// get number of mirandas
int klassVtable::get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces) {
ResourceMark rm;
GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20);
get_mirandas(mirandas, super, class_methods, local_interfaces);
return mirandas->length();
}
// fill in mirandas
void klassVtable::fill_in_mirandas(int& initialized) {
ResourceMark rm;
GrowableArray<methodOop>* mirandas = new GrowableArray<methodOop>(20);
instanceKlass *this_ik = ik();
get_mirandas(mirandas, this_ik->super(), this_ik->methods(), this_ik->local_interfaces());
int num_mirandas = mirandas->length();
for (int i = 0; i < num_mirandas; i++) {
put_method_at(mirandas->at(i), initialized);
initialized++;
}
}
void klassVtable::copy_vtable_to(vtableEntry* start) {
Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
}
void klassVtable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
int methods_length, bool * trace_name_printed) {
// search the vtable for uses of either obsolete or EMCP methods
for (int j = 0; j < methods_length; j++) {
methodOop old_method = old_methods[j];
methodOop new_method = new_methods[j];
// In the vast majority of cases we could get the vtable index
// by using: old_method->vtable_index()
// However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
// in sun.awt.X11.XFramePeer where methods occur more than once in the
// vtable, so, alas, we must do an exhaustive search.
for (int index = 0; index < length(); index++) {
if (unchecked_method_at(index) == old_method) {
put_method_at(new_method, index);
if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
if (!(*trace_name_printed)) {
// RC_TRACE_MESG macro has an embedded ResourceMark
RC_TRACE_MESG(("adjust: name=%s",
Klass::cast(old_method->method_holder())->external_name()));
*trace_name_printed = true;
}
// RC_TRACE macro has an embedded ResourceMark
RC_TRACE(0x00100000, ("vtable method update: %s(%s)",
new_method->name()->as_C_string(),
new_method->signature()->as_C_string()));
}
}
}
}
}
// Garbage collection
void klassVtable::oop_follow_contents() {
int len = length();
for (int i = 0; i < len; i++) {
MarkSweep::mark_and_push(adr_method_at(i));
}
}
#ifndef SERIALGC
void klassVtable::oop_follow_contents(ParCompactionManager* cm) {
int len = length();
for (int i = 0; i < len; i++) {
PSParallelCompact::mark_and_push(cm, adr_method_at(i));
}
}
#endif // SERIALGC
void klassVtable::oop_adjust_pointers() {
int len = length();
for (int i = 0; i < len; i++) {
MarkSweep::adjust_pointer(adr_method_at(i));
}
}
#ifndef SERIALGC
void klassVtable::oop_update_pointers(ParCompactionManager* cm) {
const int n = length();
for (int i = 0; i < n; i++) {
PSParallelCompact::adjust_pointer(adr_method_at(i));
}
}
void klassVtable::oop_update_pointers(ParCompactionManager* cm,
HeapWord* beg_addr, HeapWord* end_addr) {
const int n = length();
const int entry_size = vtableEntry::size();
int beg_idx = 0;
HeapWord* const method_0 = (HeapWord*)adr_method_at(0);
if (beg_addr > method_0) {
// it's safe to use cast, as we have guarantees on vtable size to be sane
beg_idx = int((pointer_delta(beg_addr, method_0) + entry_size - 1) / entry_size);
}
oop* const beg_oop = adr_method_at(beg_idx);
oop* const end_oop = MIN2((oop*)end_addr, adr_method_at(n));
for (oop* cur_oop = beg_oop; cur_oop < end_oop; cur_oop += entry_size) {
PSParallelCompact::adjust_pointer(cur_oop);
}
}
#endif // SERIALGC
// Iterators
void klassVtable::oop_oop_iterate(OopClosure* blk) {
int len = length();
for (int i = 0; i < len; i++) {
blk->do_oop(adr_method_at(i));
}
}
void klassVtable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) {
int len = length();
int i;
for (i = 0; i < len; i++) {
if ((HeapWord*)adr_method_at(i) >= mr.start()) break;
}
for (; i < len; i++) {
oop* adr = adr_method_at(i);
if ((HeapWord*)adr < mr.end()) blk->do_oop(adr);
}
}
//-----------------------------------------------------------------------------------------
// Itable code
// Initialize a itableMethodEntry
void itableMethodEntry::initialize(methodOop m) {
if (m == NULL) return;
_method = m;
}
klassItable::klassItable(instanceKlassHandle klass) {
_klass = klass;
if (klass->itable_length() > 0) {
itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
// First offset entry points to the first method_entry
intptr_t* method_entry = (intptr_t *)(((address)klass->as_klassOop()) + offset_entry->offset());
intptr_t* end = klass->end_of_itable();
_table_offset = (intptr_t*)offset_entry - (intptr_t*)klass->as_klassOop();
_size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
_size_method_table = (end - method_entry) / itableMethodEntry::size();
assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
return;
}
}
// This lenght of the itable was either zero, or it has not yet been initialized.
_table_offset = 0;
_size_offset_table = 0;
_size_method_table = 0;
}
// Garbage Collection
void klassItable::oop_follow_contents() {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
MarkSweep::mark_and_push((oop*)&ioe->_interface);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
MarkSweep::mark_and_push((oop*)&ime->_method);
ime++;
}
}
#ifndef SERIALGC
void klassItable::oop_follow_contents(ParCompactionManager* cm) {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
PSParallelCompact::mark_and_push(cm, (oop*)&ioe->_interface);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
PSParallelCompact::mark_and_push(cm, (oop*)&ime->_method);
ime++;
}
}
#endif // SERIALGC
void klassItable::oop_adjust_pointers() {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
MarkSweep::adjust_pointer((oop*)&ioe->_interface);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
MarkSweep::adjust_pointer((oop*)&ime->_method);
ime++;
}
}
#ifndef SERIALGC
void klassItable::oop_update_pointers(ParCompactionManager* cm) {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
PSParallelCompact::adjust_pointer((oop*)&ioe->_interface);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
PSParallelCompact::adjust_pointer((oop*)&ime->_method);
ime++;
}
}
void klassItable::oop_update_pointers(ParCompactionManager* cm,
HeapWord* beg_addr, HeapWord* end_addr) {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
oop* p = (oop*)&ioe->_interface;
PSParallelCompact::adjust_pointer(p, beg_addr, end_addr);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
oop* p = (oop*)&ime->_method;
PSParallelCompact::adjust_pointer(p, beg_addr, end_addr);
ime++;
}
}
#endif // SERIALGC
// Iterators
void klassItable::oop_oop_iterate(OopClosure* blk) {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
blk->do_oop((oop*)&ioe->_interface);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
blk->do_oop((oop*)&ime->_method);
ime++;
}
}
void klassItable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) {
// offset table
itableOffsetEntry* ioe = offset_entry(0);
for(int i = 0; i < _size_offset_table; i++) {
oop* adr = (oop*)&ioe->_interface;
if (mr.contains(adr)) blk->do_oop(adr);
ioe++;
}
// method table
itableMethodEntry* ime = method_entry(0);
for(int j = 0; j < _size_method_table; j++) {
oop* adr = (oop*)&ime->_method;
if (mr.contains(adr)) blk->do_oop(adr);
ime++;
}
}
static int initialize_count = 0;
// Initialization
void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
// Cannot be setup doing bootstrapping
if (Universe::is_bootstrapping()) return;
int num_interfaces = nof_interfaces();
if (num_interfaces > 0) {
if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count, _klass->name()->as_C_string());
// In debug mode, we got an extra NULL/NULL entry
debug_only(num_interfaces--);
assert(num_interfaces > 0, "to few interfaces in offset itable");
// Interate through all interfaces
int i;
for(i = 0; i < num_interfaces; i++) {
itableOffsetEntry* ioe = offset_entry(i);
KlassHandle interf_h (THREAD, ioe->interface_klass());
assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
}
#ifdef ASSERT
// Check that the last entry is empty
itableOffsetEntry* ioe = offset_entry(i);
assert(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
#endif
}
}
void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
objArrayHandle methods(THREAD, instanceKlass::cast(interf_h())->methods());
int nof_methods = methods()->length();
HandleMark hm;
KlassHandle klass = _klass;
assert(nof_methods > 0, "at least one method must exist for interface to be in vtable")
Handle interface_loader (THREAD, instanceKlass::cast(interf_h())->class_loader());
int ime_num = 0;
// Skip first methodOop if it is a class initializer
int i = ((methodOop)methods()->obj_at(0))->name() != vmSymbols::class_initializer_name() ? 0 : 1;
// m, method_name, method_signature, klass reset each loop so they
// don't need preserving across check_signature_loaders call
// methods needs a handle in case of gc from check_signature_loaders
for(; i < nof_methods; i++) {
methodOop m = (methodOop)methods()->obj_at(i);
symbolOop method_name = m->name();
symbolOop method_signature = m->signature();
// This is same code as in Linkresolver::lookup_instance_method_in_klasses
methodOop target = klass->uncached_lookup_method(method_name, method_signature);
while (target != NULL && target->is_static()) {
// continue with recursive lookup through the superclass
klassOop super = Klass::cast(target->method_holder())->super();
target = (super == NULL) ? methodOop(NULL) : Klass::cast(super)->uncached_lookup_method(method_name, method_signature);
}
if (target == NULL || !target->is_public() || target->is_abstract()) {
// Entry do not resolve. Leave it empty
} else {
// Entry did resolve, check loader constraints before initializing
// if checkconstraints requested
methodHandle target_h (THREAD, target); // preserve across gc
if (checkconstraints) {
Handle method_holder_loader (THREAD, instanceKlass::cast(target->method_holder())->class_loader());
if (method_holder_loader() != interface_loader()) {
ResourceMark rm(THREAD);
char* failed_type_name =
SystemDictionary::check_signature_loaders(method_signature,
method_holder_loader,
interface_loader,
true, CHECK);
if (failed_type_name != NULL) {
const char* msg = "loader constraint violation in interface "
"itable initialization: when resolving method \"%s\" the class"
" loader (instance of %s) of the current class, %s, "
"and the class loader (instance of %s) for interface "
"%s have different Class objects for the type %s "
"used in the signature";
char* sig = target_h()->name_and_sig_as_C_string();
const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
char* current = klass->name()->as_C_string();
const char* loader2 = SystemDictionary::loader_name(interface_loader());
char* iface = instanceKlass::cast(interf_h())->name()->as_C_string();
size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
strlen(current) + strlen(loader2) + strlen(iface) +
strlen(failed_type_name);
char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
iface, failed_type_name);
THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
}
}
}
// ime may have moved during GC so recalculate address
itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
}
// Progress to next entry
ime_num++;
}
}
// Update entry for specic methodOop
void klassItable::initialize_with_method(methodOop m) {
itableMethodEntry* ime = method_entry(0);
for(int i = 0; i < _size_method_table; i++) {
if (ime->method() == m) {
ime->initialize(m);
}
ime++;
}
}
void klassItable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
int methods_length, bool * trace_name_printed) {
// search the itable for uses of either obsolete or EMCP methods
for (int j = 0; j < methods_length; j++) {
methodOop old_method = old_methods[j];
methodOop new_method = new_methods[j];
itableMethodEntry* ime = method_entry(0);
for (int i = 0; i < _size_method_table; i++) {
if (ime->method() == old_method) {
ime->initialize(new_method);
if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
if (!(*trace_name_printed)) {
// RC_TRACE_MESG macro has an embedded ResourceMark
RC_TRACE_MESG(("adjust: name=%s",
Klass::cast(old_method->method_holder())->external_name()));
*trace_name_printed = true;
}
// RC_TRACE macro has an embedded ResourceMark
RC_TRACE(0x00200000, ("itable method update: %s(%s)",
new_method->name()->as_C_string(),
new_method->signature()->as_C_string()));
}
break;
}
ime++;
}
}
}
// Setup
class InterfaceVisiterClosure : public StackObj {
public:
virtual void doit(klassOop intf, int method_count) = 0;
};
// Visit all interfaces with at-least one method (excluding <clinit>)
void visit_all_interfaces(objArrayOop transitive_intf, InterfaceVisiterClosure *blk) {
// Handle array argument
for(int i = 0; i < transitive_intf->length(); i++) {
klassOop intf = (klassOop)transitive_intf->obj_at(i);
assert(Klass::cast(intf)->is_interface(), "sanity check");
// Find no. of methods excluding a <clinit>
int method_count = instanceKlass::cast(intf)->methods()->length();
if (method_count > 0) {
methodOop m = (methodOop)instanceKlass::cast(intf)->methods()->obj_at(0);
assert(m != NULL && m->is_method(), "sanity check");
if (m->name() == vmSymbols::object_initializer_name()) {
method_count--;
}
}
// Only count interfaces with at least one method
if (method_count > 0) {
blk->doit(intf, method_count);
}
}
}
class CountInterfacesClosure : public InterfaceVisiterClosure {
private:
int _nof_methods;
int _nof_interfaces;
public:
CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
int nof_methods() const { return _nof_methods; }
int nof_interfaces() const { return _nof_interfaces; }
void doit(klassOop intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
};
class SetupItableClosure : public InterfaceVisiterClosure {
private:
itableOffsetEntry* _offset_entry;
itableMethodEntry* _method_entry;
address _klass_begin;
public:
SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
_klass_begin = klass_begin;
_offset_entry = offset_entry;
_method_entry = method_entry;
}
itableMethodEntry* method_entry() const { return _method_entry; }
void doit(klassOop intf, int method_count) {
int offset = ((address)_method_entry) - _klass_begin;
_offset_entry->initialize(intf, offset);
_offset_entry++;
_method_entry += method_count;
}
};
int klassItable::compute_itable_size(objArrayHandle transitive_interfaces) {
// Count no of interfaces and total number of interface methods
CountInterfacesClosure cic;
visit_all_interfaces(transitive_interfaces(), &cic);
// Add one extra entry in debug mode, so we can null-terminate the table
int nof_methods = cic.nof_methods();
int nof_interfaces = cic.nof_interfaces();
debug_only(if (nof_interfaces > 0) nof_interfaces++);
int itable_size = calc_itable_size(nof_interfaces, nof_methods);
// Statistics
update_stats(itable_size * HeapWordSize);
return itable_size;
}
// Fill out offset table and interface klasses into the itable space
void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
if (klass->itable_length() == 0) return;
assert(!klass->is_interface(), "Should have zero length itable");
// Count no of interfaces and total number of interface methods
CountInterfacesClosure cic;
visit_all_interfaces(klass->transitive_interfaces(), &cic);
int nof_methods = cic.nof_methods();
int nof_interfaces = cic.nof_interfaces();
// Add one extra entry in debug mode, so we can null-terminate the table
debug_only(if (nof_interfaces > 0) nof_interfaces++);
assert(compute_itable_size(objArrayHandle(klass->transitive_interfaces())) ==
calc_itable_size(nof_interfaces, nof_methods),
"mismatch calculation of itable size");
// Fill-out offset table
itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
intptr_t* end = klass->end_of_itable();
assert((oop*)(ime + nof_methods) <= klass->start_of_static_fields(), "wrong offset calculation (1)");
assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
// Visit all interfaces and initialize itable offset table
SetupItableClosure sic((address)klass->as_klassOop(), ioe, ime);
visit_all_interfaces(klass->transitive_interfaces(), &sic);
#ifdef ASSERT
ime = sic.method_entry();
oop* v = (oop*) klass->end_of_itable();
assert( (oop*)(ime) == v, "wrong offset calculation (2)");
#endif
}
// m must be a method in an interface
int klassItable::compute_itable_index(methodOop m) {
klassOop intf = m->method_holder();
assert(instanceKlass::cast(intf)->is_interface(), "sanity check");
objArrayOop methods = instanceKlass::cast(intf)->methods();
int index = 0;
while(methods->obj_at(index) != m) {
index++;
assert(index < methods->length(), "should find index for resolve_invoke");
}
// Adjust for <clinit>, which is left out of table if first method
if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->name() == vmSymbols::class_initializer_name()) {
index--;
}
return index;
}
void klassVtable::verify(outputStream* st, bool forced) {
// make sure table is initialized
if (!Universe::is_fully_initialized()) return;
#ifndef PRODUCT
// avoid redundant verifies
if (!forced && _verify_count == Universe::verify_count()) return;
_verify_count = Universe::verify_count();
#endif
oop* end_of_obj = (oop*)_klass() + _klass()->size();
oop* end_of_vtable = (oop *)&table()[_length];
if (end_of_vtable > end_of_obj) {
fatal1("klass %s: klass object too short (vtable extends beyond end)",
_klass->internal_name());
}
for (int i = 0; i < _length; i++) table()[i].verify(this, st);
// verify consistency with superKlass vtable
klassOop super = _klass->super();
if (super != NULL) {
instanceKlass* sk = instanceKlass::cast(super);
klassVtable* vt = sk->vtable();
for (int i = 0; i < vt->length(); i++) {
verify_against(st, vt, i);
}
}
}
void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
vtableEntry* vte = &vt->table()[index];
if (vte->method()->name() != table()[index].method()->name() ||
vte->method()->signature() != table()[index].method()->signature()) {
fatal("mismatched name/signature of vtable entries");
}
}
#ifndef PRODUCT
void klassVtable::print() {
ResourceMark rm;
tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
for (int i = 0; i < length(); i++) {
table()[i].print();
tty->cr();
}
}
#endif
void vtableEntry::verify(klassVtable* vt, outputStream* st) {
NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
assert(method() != NULL, "must have set method");
method()->verify();
// we sub_type, because it could be a miranda method
if (!vt->klass()->is_subtype_of(method()->method_holder())) {
#ifndef PRODUCT
print();
#endif
fatal1("vtableEntry %#lx: method is from subclass", this);
}
}
#ifndef PRODUCT
void vtableEntry::print() {
ResourceMark rm;
tty->print("vtableEntry %s: ", method()->name()->as_C_string());
if (Verbose) {
tty->print("m %#lx ", (address)method());
}
}
class VtableStats : AllStatic {
public:
static int no_klasses; // # classes with vtables
static int no_array_klasses; // # array classes
static int no_instance_klasses; // # instanceKlasses
static int sum_of_vtable_len; // total # of vtable entries
static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
static int fixed; // total fixed overhead in bytes
static int filler; // overhead caused by filler bytes
static int entries; // total bytes consumed by vtable entries
static int array_entries; // total bytes consumed by array vtable entries
static void do_class(klassOop k) {
Klass* kl = k->klass_part();
klassVtable* vt = kl->vtable();
if (vt == NULL) return;
no_klasses++;
if (kl->oop_is_instance()) {
no_instance_klasses++;
kl->array_klasses_do(do_class);
}
if (kl->oop_is_array()) {
no_array_klasses++;
sum_of_array_vtable_len += vt->length();
}
sum_of_vtable_len += vt->length();
}
static void compute() {
SystemDictionary::classes_do(do_class);
fixed = no_klasses * oopSize; // vtable length
// filler size is a conservative approximation
filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(instanceKlass) - sizeof(arrayKlass) - 1);
entries = sizeof(vtableEntry) * sum_of_vtable_len;
array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
}
};
int VtableStats::no_klasses = 0;
int VtableStats::no_array_klasses = 0;
int VtableStats::no_instance_klasses = 0;
int VtableStats::sum_of_vtable_len = 0;
int VtableStats::sum_of_array_vtable_len = 0;
int VtableStats::fixed = 0;
int VtableStats::filler = 0;
int VtableStats::entries = 0;
int VtableStats::array_entries = 0;
void klassVtable::print_statistics() {
ResourceMark rm;
HandleMark hm;
VtableStats::compute();
tty->print_cr("vtable statistics:");
tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
tty->print_cr("%6d bytes total", total);
}
bool klassVtable::check_no_old_entries() {
// Check that there really is no entry
for (int i = 0; i < length(); i++) {
methodOop m = unchecked_method_at(i);
if (m != NULL) {
if (m->is_old()) {
return false;
}
}
}
return true;
}
void klassVtable::dump_vtable() {
tty->print_cr("vtable dump --");
for (int i = 0; i < length(); i++) {
methodOop m = unchecked_method_at(i);
if (m != NULL) {
tty->print(" (%5d) ", i);
m->access_flags().print_on(tty);
tty->print(" -- ");
m->print_name(tty);
tty->cr();
}
}
}
int klassItable::_total_classes; // Total no. of classes with itables
long klassItable::_total_size; // Total no. of bytes used for itables
void klassItable::print_statistics() {
tty->print_cr("itable statistics:");
tty->print_cr("%6d classes with itables", _total_classes);
tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
}
#endif // PRODUCT
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