truffle: src/share/vm/oops/klassVtable.cpp comparison

comparison src/share/vm/oops/klassVtable.cpp @ 12264:b2e698d2276c

8014013: CallInfo structure no longer accurately reports the result of a LinkResolver operation Summary: Enhance method resolution and resulting data structures, plus some refactoring. Reviewed-by: twisti, acorn, jrose

author	drchase
date	Fri, 13 Sep 2013 22:38:02 -0400
parents	08236d966eea
children	36b97be47bde

comparison

equal deleted inserted replaced

-:2c98370f2611
+:b2e698d2276c
 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
+// 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
+// interface I, and none of C's superclasses implements I.
-// of its super classes implement (i.e there is no method of any access, with
+// Let's say there is an abstract method m in I that neither C
-// the same name and signature as m), then m is a Miranda method which is
+// 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_ret, int* num_new_mirandas,
 GrowableArray<Method*>* all_mirandas, Klass* super,
 *vtable_length_ret = vtable_length;
 }
 int klassVtable::index_of(Method* m, int len) const {
-assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
+assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
 return m->vtable_index();
 }
+// Copy super class's vtable to the first part (prefix) of this class's vtable,
+// and return the number of entries copied.  Expects that 'super' is the Java
+// super class (arrays can have "array" super classes that must be skipped).
 int klassVtable::initialize_from_super(KlassHandle super) {
 if (super.is_null()) {
 return 0;
 } else {
 // copy methods from superKlass
 #endif
 return superVtable->length();
 }
 }
-// Revised lookup semantics   introduced 1.3 (Kestral beta)
+//
+// Revised lookup semantics   introduced 1.3 (Kestrel 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());
 }
 Array<Method*>* methods = ik()->methods();
 int len = methods->length();
 int initialized = super_vtable_len;
-// update_inherited_vtable can stop for gc - ensure using handles
+// Check each of this class's methods against super;
+// if override, replace in copy of super vtable, otherwise append to end
 for (int i = 0; i < len; i++) {
+// update_inherited_vtable can stop for gc - ensure using handles
 HandleMark hm(THREAD);
 assert(methods->at(i)->is_method(), "must be a Method*");
 methodHandle mh(THREAD, methods->at(i));
 bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
 mh()->set_vtable_index(initialized); // set primary vtable index
 initialized++;
 }
 }
-// add miranda methods; it will also update the value of initialized
+// add miranda methods to end of vtable.
-fill_in_mirandas(&initialized);
+initialized = fill_in_mirandas(initialized);
 // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
-// package_private -> publicprotected), the vtable might actually be smaller than our initial
+// package_private -> public/protected), 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);
 }
 }
 return superk;
 }
-// Methods that are "effectively" final don't need vtable entries.
-bool method_is_effectively_final(
-AccessFlags klass_flags, methodHandle target) {
-return target->is_final() || klass_flags.is_final() && !target->is_overpass();
-}
 // Update child's copy of super vtable for overrides
-// OR return true if a new vtable entry is required
+// 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_inherited_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");
+assert(klass == target_method()->method_holder(), "caller resp.");
 // 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(Method::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 (method_is_effectively_final(klass->access_flags(), target_method)) {
+if (target_method->is_final_method(klass->access_flags())) {
 // 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;
+} else if (klass->is_interface()) {
+allocate_new = false;  // see note below in needs_new_vtable_entry
+// An interface never allocates new vtable slots, only inherits old ones.
+// This method will either be assigned its own itable index later,
+// or be assigned an inherited vtable index in the loop below.
+target_method()->set_vtable_index(Method::pending_itable_index);
 }
 // we need a new entry if there is no superclass
 if (klass->super() == NULL) {
 return allocate_new;
 Klass* super,
 Handle classloader,
 Symbol* classname,
 AccessFlags class_flags,
 TRAPS) {
+if (class_flags.is_interface()) {
-if (method_is_effectively_final(class_flags, target_method) ||
+// Interfaces do not use vtables, so there is no point to assigning
+// a vtable index to any of their methods.  If we refrain from doing this,
+// we can use Method::_vtable_index to hold the itable index
+return false;
+}
+if (target_method->is_final_method(class_flags) ||
 // 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
 }
 }
 return Method::invalid_vtable_index;
 }
-// check if an entry is miranda
+// check if an entry at an index is miranda
+// requires that method m at entry be declared ("held") by an interface.
 bool klassVtable::is_miranda_entry_at(int i) {
 Method* m = method_at(i);
 Klass* method_holder = m->method_holder();
 InstanceKlass *mhk = InstanceKlass::cast(method_holder);
 return true;
 }
 return false;
 }
-// check if a method is a miranda method, given a class's methods table and it's super
+// check if a method is a miranda method, given a class's methods table and its super
+// "miranda" means not static, not defined by this class, and not defined
+// in super unless it is private and therefore inaccessible to this class.
 // the caller must make sure that the method belongs to an interface implemented by the class
 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
 if (m->is_static()) {
 return false;
 }
 }
 return false;
 }
+// Scans current_interface_methods for miranda methods that do not
+// already appear in new_mirandas and are also not defined-and-non-private
+// in super (superclass).  These mirandas are added to all_mirandas if it is
+// not null; in addition, those that are not duplicates of miranda methods
+// inherited by super from its interfaces are added to new_mirandas.
+// Thus, new_mirandas will be the set of mirandas that this class introduces,
+// all_mirandas will be the set of all mirandas applicable to this class
+// including all defined in superclasses.
 void klassVtable::add_new_mirandas_to_lists(
 GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
 Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
 Klass* super) {
 // iterate thru the current interface's method to see if it a miranda
 sik->methods(), class_methods, super);
 }
 }
 }
-// fill in mirandas
+// Discover miranda methods ("miranda" = "interface abstract, no binding"),
-void klassVtable::fill_in_mirandas(int* initialized) {
+// and append them into the vtable starting at index initialized,
+// return the new value of initialized.
+int klassVtable::fill_in_mirandas(int initialized) {
 GrowableArray<Method*> mirandas(20);
 get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
 ik()->local_interfaces());
 for (int i = 0; i < mirandas.length(); i++) {
-put_method_at(mirandas.at(i), *initialized);
+put_method_at(mirandas.at(i), initialized);
-++(*initialized);
+++initialized;
 }
-}
+return initialized;
+}
+// Copy this class's vtable to the vtable beginning at start.
+// Used to copy superclass vtable to prefix of subclass's vtable.
 void klassVtable::copy_vtable_to(vtableEntry* start) {
 Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
 }
 #if INCLUDE_JVMTI
 static int initialize_count = 0;
 // Initialization
 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
+if (_klass->is_interface()) {
+// This needs to go after vtable indexes are assigned but
+// before implementors need to know the number of itable indexes.
+assign_itable_indexes_for_interface(_klass());
+}
 // Cannot be setup doing bootstrapping, interfaces don't have
 // itables, and klass with only ones entry have empty itables
 if (Universe::is_bootstrapping() ||
 _klass->is_interface() ||
 _klass->itable_length() == itableOffsetEntry::size()) return;
 itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
 guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
 }
+inline bool interface_method_needs_itable_index(Method* m) {
+if (m->is_static())           return false;   // e.g., Stream.empty
+if (m->is_initializer())      return false;   // <init> or <clinit>
+// If an interface redeclares a method from java.lang.Object,
+// it should already have a vtable index, don't touch it.
+// e.g., CharSequence.toString (from initialize_vtable)
+// if (m->has_vtable_index())  return false; // NO!
+return true;
+}
+int klassItable::assign_itable_indexes_for_interface(Klass* klass) {
+// an interface does not have an itable, but its methods need to be numbered
+if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count,
+klass->name()->as_C_string());
+Array<Method*>* methods = InstanceKlass::cast(klass)->methods();
+int nof_methods = methods->length();
+int ime_num = 0;
+for (int i = 0; i < nof_methods; i++) {
+Method* m = methods->at(i);
+if (interface_method_needs_itable_index(m)) {
+assert(!m->is_final_method(), "no final interface methods");
+// If m is already assigned a vtable index, do not disturb it.
+if (!m->has_vtable_index()) {
+assert(m->vtable_index() == Method::pending_itable_index, "set by initialize_vtable");
+m->set_itable_index(ime_num);
+// Progress to next itable entry
+ime_num++;
+}
+}
+}
+assert(ime_num == method_count_for_interface(klass), "proper sizing");
+return ime_num;
+}
+int klassItable::method_count_for_interface(Klass* interf) {
+assert(interf->oop_is_instance(), "must be");
+assert(interf->is_interface(), "must be");
+Array<Method*>* methods = InstanceKlass::cast(interf)->methods();
+int nof_methods = methods->length();
+while (nof_methods > 0) {
+Method* m = methods->at(nof_methods-1);
+if (m->has_itable_index()) {
+int length = m->itable_index() + 1;
+#ifdef ASSERT
+while (nof_methods = 0) {
+m = methods->at(--nof_methods);
+assert(!m->has_itable_index() || m->itable_index() < length, "");
+}
+#endif //ASSERT
+return length;  // return the rightmost itable index, plus one
+}
+nof_methods -= 1;
+}
+// no methods have itable indexes
+return 0;
+}
 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
 Array<Method*>* methods = 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;
+int ime_count = method_count_for_interface(interf_h());
-// Skip first Method* if it is a class initializer
+for (int i = 0; i < nof_methods; i++) {
-int i = methods->at(0)->is_static_initializer() ? 1 : 0;
-// 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++) {
 Method* m = methods->at(i);
-Symbol* method_name = m->name();
+methodHandle target;
-Symbol* method_signature = m->signature();
+if (m->has_itable_index()) {
+LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK);
-// This is same code as in Linkresolver::lookup_instance_method_in_klasses
-Method* target = klass->uncached_lookup_method(method_name, method_signature);
-while (target != NULL && target->is_static()) {
-// continue with recursive lookup through the superclass
-Klass* super = target->method_holder()->super();
-target = (super == NULL) ? (Method*)NULL : 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, target->method_holder()->class_loader());
 if (method_holder_loader() != interface_loader()) {
 ResourceMark rm(THREAD);
 Symbol* failed_type_symbol =
-SystemDictionary::check_signature_loaders(method_signature,
+SystemDictionary::check_signature_loaders(m->signature(),
 method_holder_loader,
 interface_loader,
 true, CHECK);
 if (failed_type_symbol != 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();
+char* sig = target()->name_and_sig_as_C_string();
 const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
-char* current = klass->name()->as_C_string();
+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();
 char* failed_type_name = failed_type_symbol->as_C_string();
 size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
 strlen(current) + strlen(loader2) + strlen(iface) +
 }
 }
 }
 // ime may have moved during GC so recalculate address
-itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
+int ime_num = m->itable_index();
-}
+assert(ime_num < ime_count, "oob");
-// Progress to next entry
+itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target());
-ime_num++;
+}
 }
 }
 // Update entry for specific Method*
 void klassItable::initialize_with_method(Method* m) {
 class InterfaceVisiterClosure : public StackObj {
 public:
 virtual void doit(Klass* intf, int method_count) = 0;
 };
-// Visit all interfaces with at-least one method (excluding <clinit>)
+// Visit all interfaces with at least one itable method
 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
 // Handle array argument
 for(int i = 0; i < transitive_intf->length(); i++) {
 Klass* intf = transitive_intf->at(i);
 assert(intf->is_interface(), "sanity check");
-// Find no. of methods excluding a <clinit>
+// Find no. of itable methods
-int method_count = InstanceKlass::cast(intf)->methods()->length();
+int method_count = 0;
-if (method_count > 0) {
+// method_count = klassItable::method_count_for_interface(intf);
-Method* m = InstanceKlass::cast(intf)->methods()->at(0);
+Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
-assert(m != NULL && m->is_method(), "sanity check");
+if (methods->length() > 0) {
-if (m->name() == vmSymbols::object_initializer_name()) {
+for (int i = methods->length(); --i >= 0; ) {
-method_count--;
+if (interface_method_needs_itable_index(methods->at(i))) {
+method_count++;
+}
 }
 }
 // Only count interfaces with at least one method
 if (method_count > 0) {
 assert( (oop*)(ime) == v, "wrong offset calculation (2)");
 #endif
 }
-// m must be a method in an interface
+// inverse to itable_index
-int klassItable::compute_itable_index(Method* m) {
-InstanceKlass* intf = m->method_holder();
-assert(intf->is_interface(), "sanity check");
-Array<Method*>* methods = intf->methods();
-int index = 0;
-while(methods->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 && methods->at(0)->is_static_initializer()) {
-index--;
-}
-return index;
-}
-// inverse to compute_itable_index
 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
 assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
+assert(intf->verify_itable_index(itable_index), "");
 Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
+if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
+return NULL;                // help caller defend against bad indexes
 int index = itable_index;
-// Adjust for <clinit>, which is left out of table if first method
-if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
-index++;
-}
-if (itable_index < 0 || index >= methods->length())
-return NULL;                // help caller defend against bad indexes
 Method* m = methods->at(index);
-assert(compute_itable_index(m) == itable_index, "correct inverse");
+int index2 = -1;
+while (!m->has_itable_index() ||
+(index2 = m->itable_index()) != itable_index) {
+assert(index2 < itable_index, "monotonic");
+if (++index == methods->length())
+return NULL;
+m = methods->at(index);
+}
+assert(m->itable_index() == itable_index, "correct inverse");
 return m;
 }
 void klassVtable::verify(outputStream* st, bool forced) {

Mercurial > hg > truffle

comparison src/share/vm/oops/klassVtable.cpp @ 12264:b2e698d2276c