jdk-sandbox: comparison hotspot/src/share/vm/oops/constantPool.cpp

equal deleted inserted replaced

-:02a1fc064144
+:54713555867e
 #include "runtime/signature.hpp"
 #include "runtime/vframe.hpp"
 #include "utilities/copy.hpp"
 ConstantPool* ConstantPool::allocate(ClassLoaderData* loader_data, int length, TRAPS) {
-// Tags are RW but comment below applies to tags also.
 Array<u1>* tags = MetadataFactory::new_writeable_array<u1>(loader_data, length, 0, CHECK_NULL);
 int size = ConstantPool::size(length);
+return new (loader_data, size, true, MetaspaceObj::ConstantPoolType, THREAD) ConstantPool(tags);
-// CDS considerations:
-// Allocate read-write but may be able to move to read-only at dumping time
-// if all the klasses are resolved.  The only other field that is writable is
-// the resolved_references array, which is recreated at startup time.
-// But that could be moved to InstanceKlass (although a pain to access from
-// assembly code).  Maybe it could be moved to the cpCache which is RW.
-return new (loader_data, size, false, MetaspaceObj::ConstantPoolType, THREAD) ConstantPool(tags);
 }
 #ifdef ASSERT
 // MetaspaceObj allocation invariant is calloc equivalent memory
 #endif
 ConstantPool::ConstantPool(Array<u1>* tags) :
 _tags(tags),
-_length(tags->length()),
+_length(tags->length()) {
-_flags(0) {
 assert(_tags != NULL, "invariant");
 assert(tags->length() == _length, "invariant");
 assert(tag_array_is_zero_initialized(tags), "invariant");
-assert(0 == _flags, "invariant");
+assert(0 == flags(), "invariant");
 assert(0 == version(), "invariant");
 assert(NULL == _pool_holder, "invariant");
 }
 void ConstantPool::deallocate_contents(ClassLoaderData* loader_data) {
-MetadataFactory::free_metadata(loader_data, cache());
+if (cache() != NULL) {
-set_cache(NULL);
+MetadataFactory::free_array<u2>(loader_data, reference_map());
-MetadataFactory::free_array<u2>(loader_data, reference_map());
+set_reference_map(NULL);
-set_reference_map(NULL);
+MetadataFactory::free_metadata(loader_data, cache());
+set_cache(NULL);
+}
+MetadataFactory::free_array<Klass*>(loader_data, resolved_klasses());
+set_resolved_klasses(NULL);
 MetadataFactory::free_array<jushort>(loader_data, operands());
 set_operands(NULL);
 release_C_heap_structures();
 // walk constant pool and decrement symbol reference counts
 unreference_symbols();
 }
 objArrayOop ConstantPool::resolved_references() const {
-return (objArrayOop)JNIHandles::resolve(_resolved_references);
+return (objArrayOop)JNIHandles::resolve(_cache->resolved_references());
 }
 // Create resolved_references array and mapping array for original cp indexes
 // The ldc bytecode was rewritten to have the resolved reference array index so need a way
 // to map it back for resolving and some unlikely miscellaneous uses.
 Handle refs_handle (THREAD, (oop)stom);  // must handleize.
 set_resolved_references(loader_data->add_handle(refs_handle));
 }
 }
+void ConstantPool::allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS) {
+// A ConstantPool can't possibly have 0xffff valid class entries,
+// because entry #0 must be CONSTANT_Invalid, and each class entry must refer to a UTF8
+// entry for the class's name. So at most we will have 0xfffe class entries.
+// This allows us to use 0xffff (ConstantPool::_temp_resolved_klass_index) to indicate
+// UnresolvedKlass entries that are temporarily created during class redefinition.
+assert(num_klasses < CPKlassSlot::_temp_resolved_klass_index, "sanity");
+assert(resolved_klasses() == NULL, "sanity");
+Array<Klass*>* rk = MetadataFactory::new_writeable_array<Klass*>(loader_data, num_klasses, CHECK);
+set_resolved_klasses(rk);
+}
+void ConstantPool::initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS) {
+int len = length();
+int num_klasses = 0;
+for (int i = 1; i <len; i++) {
+switch (tag_at(i).value()) {
+case JVM_CONSTANT_ClassIndex:
+{
+const int class_index = klass_index_at(i);
+unresolved_klass_at_put(i, class_index, num_klasses++);
+}
+break;
+#ifndef PRODUCT
+case JVM_CONSTANT_Class:
+case JVM_CONSTANT_UnresolvedClass:
+case JVM_CONSTANT_UnresolvedClassInError:
+// All of these should have been reverted back to ClassIndex before calling
+// this function.
+ShouldNotReachHere();
+#endif
+}
+}
+allocate_resolved_klasses(loader_data, num_klasses, THREAD);
+}
+// Anonymous class support:
+void ConstantPool::klass_at_put(int class_index, int name_index, int resolved_klass_index, Klass* k, Symbol* name) {
+assert(is_within_bounds(class_index), "index out of bounds");
+assert(is_within_bounds(name_index), "index out of bounds");
+assert((resolved_klass_index & 0xffff0000) == 0, "must be");
+*int_at_addr(class_index) =
+build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index);
+symbol_at_put(name_index, name);
+name->increment_refcount();
+Klass** adr = resolved_klasses()->adr_at(resolved_klass_index);
+OrderAccess::release_store_ptr((Klass* volatile *)adr, k);
+// The interpreter assumes when the tag is stored, the klass is resolved
+// and the Klass* non-NULL, so we need hardware store ordering here.
+if (k != NULL) {
+release_tag_at_put(class_index, JVM_CONSTANT_Class);
+} else {
+release_tag_at_put(class_index, JVM_CONSTANT_UnresolvedClass);
+}
+}
+// Anonymous class support:
+void ConstantPool::klass_at_put(int class_index, Klass* k) {
+assert(k != NULL, "must be valid klass");
+CPKlassSlot kslot = klass_slot_at(class_index);
+int resolved_klass_index = kslot.resolved_klass_index();
+Klass** adr = resolved_klasses()->adr_at(resolved_klass_index);
+OrderAccess::release_store_ptr((Klass* volatile *)adr, k);
+// The interpreter assumes when the tag is stored, the klass is resolved
+// and the Klass* non-NULL, so we need hardware store ordering here.
+release_tag_at_put(class_index, JVM_CONSTANT_Class);
+}
 // CDS support. Create a new resolved_references array.
 void ConstantPool::restore_unshareable_info(TRAPS) {
 assert(is_constantPool(), "ensure C++ vtable is restored");
+assert(on_stack(), "should always be set for shared constant pools");
+assert(is_shared(), "should always be set for shared constant pools");
 // Only create the new resolved references array if it hasn't been attempted before
 if (resolved_references() != NULL) return;
 // restore the C++ vtable from the shared archive
 // Save the length for restoration.  It is not necessarily the same length
 // as reference_map.length() if invokedynamic is saved.
 set_resolved_reference_length(
 resolved_references() != NULL ? resolved_references()->length() : 0);
 set_resolved_references(NULL);
+// Shared ConstantPools are in the RO region, so the _flags cannot be modified.
+// The _on_stack flag is used to prevent ConstantPools from deallocation during
+// class redefinition. Since shared ConstantPools cannot be deallocated anyway,
+// we always set _on_stack to true to avoid having to change _flags during runtime.
+_flags |= (_on_stack | _is_shared);
 }
 int ConstantPool::cp_to_object_index(int cp_index) {
 // this is harder don't do this so much.
 int i = reference_map()->find(cp_index);
 assert(THREAD->is_Java_thread(), "must be a Java thread");
 // A resolved constantPool entry will contain a Klass*, otherwise a Symbol*.
 // It is not safe to rely on the tag bit's here, since we don't have a lock, and
 // the entry and tag is not updated atomicly.
-CPSlot entry = this_cp->slot_at(which);
+CPKlassSlot kslot = this_cp->klass_slot_at(which);
-if (entry.is_resolved()) {
+int resolved_klass_index = kslot.resolved_klass_index();
-assert(entry.get_klass()->is_klass(), "must be");
+int name_index = kslot.name_index();
-// Already resolved - return entry.
+assert(this_cp->tag_at(name_index).is_symbol(), "sanity");
-return entry.get_klass();
+Klass* klass = this_cp->resolved_klasses()->at(resolved_klass_index);
+if (klass != NULL) {
+return klass;
 }
 // This tag doesn't change back to unresolved class unless at a safepoint.
 if (this_cp->tag_at(which).is_unresolved_klass_in_error()) {
 // The original attempt to resolve this constant pool entry failed so find the
 throw_resolution_error(this_cp, which, CHECK_0);
 ShouldNotReachHere();
 }
 Handle mirror_handle;
-Symbol* name = entry.get_symbol();
+Symbol* name = this_cp->symbol_at(name_index);
 Handle loader (THREAD, this_cp->pool_holder()->class_loader());
 Handle protection_domain (THREAD, this_cp->pool_holder()->protection_domain());
 Klass* k = SystemDictionary::resolve_or_fail(name, loader, protection_domain, true, THREAD);
 if (!HAS_PENDING_EXCEPTION) {
 // preserve the resolved klass from unloading
 if (save_resolution_error) {
 save_and_throw_exception(this_cp, which, constantTag(JVM_CONSTANT_UnresolvedClass), CHECK_NULL);
 // If CHECK_NULL above doesn't return the exception, that means that
 // some other thread has beaten us and has resolved the class.
 // To preserve old behavior, we return the resolved class.
-entry = this_cp->resolved_klass_at(which);
+klass = this_cp->resolved_klasses()->at(resolved_klass_index);
-assert(entry.is_resolved(), "must be resolved if exception was cleared");
+assert(klass != NULL, "must be resolved if exception was cleared");
-assert(entry.get_klass()->is_klass(), "must be resolved to a klass");
+return klass;
-return entry.get_klass();
 } else {
 return NULL;  // return the pending exception
 }
 }
 // logging for class+resolve.
 if (log_is_enabled(Debug, class, resolve)){
 trace_class_resolution(this_cp, k);
 }
-this_cp->klass_at_put(which, k);
+Klass** adr = this_cp->resolved_klasses()->adr_at(resolved_klass_index);
-entry = this_cp->resolved_klass_at(which);
+OrderAccess::release_store_ptr((Klass* volatile *)adr, k);
-assert(entry.is_resolved() && entry.get_klass()->is_klass(), "must be resolved at this point");
+// The interpreter assumes when the tag is stored, the klass is resolved
-return entry.get_klass();
+// and the Klass* stored in _resolved_klasses is non-NULL, so we need
+// hardware store ordering here.
+this_cp->release_tag_at_put(which, JVM_CONSTANT_Class);
+return k;
 }
 // Does not update ConstantPool* - to avoid any exception throwing. Used
 // by compiler and exception handling.  Also used to avoid classloads for
 // instanceof operations. Returns NULL if the class has not been loaded or
 // if the verification of constant pool failed
 Klass* ConstantPool::klass_at_if_loaded(const constantPoolHandle& this_cp, int which) {
-CPSlot entry = this_cp->slot_at(which);
+CPKlassSlot kslot = this_cp->klass_slot_at(which);
-if (entry.is_resolved()) {
+int resolved_klass_index = kslot.resolved_klass_index();
-assert(entry.get_klass()->is_klass(), "must be");
+int name_index = kslot.name_index();
-return entry.get_klass();
+assert(this_cp->tag_at(name_index).is_symbol(), "sanity");
+Klass* k = this_cp->resolved_klasses()->at(resolved_klass_index);
+if (k != NULL) {
+return k;
 } else {
-assert(entry.is_unresolved(), "must be either symbol or klass");
 Thread *thread = Thread::current();
-Symbol* name = entry.get_symbol();
+Symbol* name = this_cp->symbol_at(name_index);
 oop loader = this_cp->pool_holder()->class_loader();
 oop protection_domain = this_cp->pool_holder()->protection_domain();
 Handle h_prot (thread, protection_domain);
 Handle h_loader (thread, loader);
 Klass* k = SystemDictionary::find(name, h_loader, h_prot, thread);
 Klass* ConstantPool::klass_ref_at(int which, TRAPS) {
 return klass_at(klass_ref_index_at(which), THREAD);
 }
 Symbol* ConstantPool::klass_name_at(int which) const {
-assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
+return symbol_at(klass_slot_at(which).name_index());
-"Corrupted constant pool");
-// A resolved constantPool entry will contain a Klass*, otherwise a Symbol*.
-// It is not safe to rely on the tag bit's here, since we don't have a lock, and the entry and
-// tag is not updated atomicly.
-CPSlot entry = slot_at(which);
-if (entry.is_resolved()) {
-// Already resolved - return entry's name.
-assert(entry.get_klass()->is_klass(), "must be");
-return entry.get_klass()->name();
-} else {
-assert(entry.is_unresolved(), "must be either symbol or klass");
-return entry.get_symbol();
-}
 }
 Symbol* ConstantPool::klass_ref_at_noresolve(int which) {
 jint ref_index = klass_ref_index_at(which);
 return klass_at_noresolve(ref_index);
 }
 // Iterate over symbols and decrement ones which are Symbol*s
 // This is done during GC.
-// Only decrement the UTF8 symbols. Unresolved classes and strings point to
+// Only decrement the UTF8 symbols. Strings point to
 // these symbols but didn't increment the reference count.
 void ConstantPool::unreference_symbols() {
 for (int index = 1; index < length(); index++) { // Index 0 is unused
 constantTag tag = tag_at(index);
 if (tag.is_symbol()) {
 const constantPoolHandle& to_cp, int to_i,
 TRAPS) {
 int tag = from_cp->tag_at(from_i).value();
 switch (tag) {
-case JVM_CONSTANT_Class:
-{
-Klass* k = from_cp->klass_at(from_i, CHECK);
-to_cp->klass_at_put(to_i, k);
-} break;
 case JVM_CONSTANT_ClassIndex:
 {
 jint ki = from_cp->klass_index_at(from_i);
 to_cp->klass_index_at_put(to_i, ki);
 } break;
 {
 jint si = from_cp->string_index_at(from_i);
 to_cp->string_index_at_put(to_i, si);
 } break;
+case JVM_CONSTANT_Class:
 case JVM_CONSTANT_UnresolvedClass:
 case JVM_CONSTANT_UnresolvedClassInError:
 {
-// Can be resolved after checking tag, so check the slot first.
+// Revert to JVM_CONSTANT_ClassIndex
-CPSlot entry = from_cp->slot_at(from_i);
+int name_index = from_cp->klass_slot_at(from_i).name_index();
-if (entry.is_resolved()) {
+assert(from_cp->tag_at(name_index).is_symbol(), "sanity");
-assert(entry.get_klass()->is_klass(), "must be");
+to_cp->klass_index_at_put(to_i, name_index);
-// Already resolved
-to_cp->klass_at_put(to_i, entry.get_klass());
-} else {
-to_cp->unresolved_klass_at_put(to_i, entry.get_symbol());
-}
 } break;
 case JVM_CONSTANT_String:
 {
 Symbol* s = from_cp->unresolved_string_at(from_i);
 {
 ShouldNotReachHere();
 } break;
 }
 } // end copy_entry_to()
 // Search constant pool search_cp for an entry that matches this
 // constant pool's entry at pattern_i. Returns the index of a
 // matching entry or zero (0) if there is no matching entry.
 int ConstantPool::find_matching_entry(int pattern_i,
 void ConstantPool::set_on_stack(const bool value) {
 if (value) {
 // Only record if it's not already set.
 if (!on_stack()) {
+assert(!is_shared(), "should always be set for shared constant pools");
 _flags |= _on_stack;
 MetadataOnStackMark::record(this);
 }
 } else {
 // Clearing is done single-threadedly.
-_flags &= ~_on_stack;
+if (!is_shared()) {
+_flags &= ~_on_stack;
+}
 }
 }
 // JSR 292 support for patching constant pool oops after the class is linked and
 // the oop array for resolved references are created.
 st->print_cr(" - holder: " INTPTR_FORMAT, p2i(pool_holder()));
 }
 st->print_cr(" - cache: " INTPTR_FORMAT, p2i(cache()));
 st->print_cr(" - resolved_references: " INTPTR_FORMAT, p2i(resolved_references()));
 st->print_cr(" - reference_map: " INTPTR_FORMAT, p2i(reference_map()));
+st->print_cr(" - resolved_klasses: " INTPTR_FORMAT, p2i(resolved_klasses()));
 for (int index = 1; index < length(); index++) {      // Index 0 is unused
 ((ConstantPool*)this)->print_entry_on(index, st);
 switch (tag_at(index).value()) {
 case JVM_CONSTANT_Long :
 st->print(" signature_index=%d", signature_ref_index_at(index));
 break;
 case JVM_CONSTANT_Utf8 :
 symbol_at(index)->print_value_on(st);
 break;
+case JVM_CONSTANT_ClassIndex: {
+int name_index = *int_at_addr(index);
+st->print("klass_index=%d ", name_index);
+symbol_at(name_index)->print_value_on(st);
+}
+break;
 case JVM_CONSTANT_UnresolvedClass :               // fall-through
 case JVM_CONSTANT_UnresolvedClassInError: {
-CPSlot entry = slot_at(index);
+CPKlassSlot kslot = klass_slot_at(index);
-if (entry.is_resolved()) {
+int resolved_klass_index = kslot.resolved_klass_index();
-entry.get_klass()->print_value_on(st);
+int name_index = kslot.name_index();
-} else {
+assert(tag_at(name_index).is_symbol(), "sanity");
-entry.get_symbol()->print_value_on(st);
-}
+Klass* klass = resolved_klasses()->at(resolved_klass_index);
+if (klass != NULL) {
+klass->print_value_on(st);
+} else {
+symbol_at(name_index)->print_value_on(st);
+}
 }
 break;
 case JVM_CONSTANT_MethodHandle :
 case JVM_CONSTANT_MethodHandleInError :
 st->print("ref_kind=%d", method_handle_ref_kind_at(index));
 void ConstantPool::verify_on(outputStream* st) {
 guarantee(is_constantPool(), "object must be constant pool");
 for (int i = 0; i< length();  i++) {
 constantTag tag = tag_at(i);
-CPSlot entry = slot_at(i);
+if (tag.is_klass() || tag.is_unresolved_klass()) {
-if (tag.is_klass()) {
+guarantee(klass_name_at(i)->refcount() != 0, "should have nonzero reference count");
-if (entry.is_resolved()) {
-guarantee(entry.get_klass()->is_klass(),    "should be klass");
-}
-} else if (tag.is_unresolved_klass()) {
-if (entry.is_resolved()) {
-guarantee(entry.get_klass()->is_klass(),    "should be klass");
-}
 } else if (tag.is_symbol()) {
+CPSlot entry = slot_at(i);
 guarantee(entry.get_symbol()->refcount() != 0, "should have nonzero reference count");
 } else if (tag.is_string()) {
+CPSlot entry = slot_at(i);
 guarantee(entry.get_symbol()->refcount() != 0, "should have nonzero reference count");
 }
 }
 if (cache() != NULL) {
 // Note: cache() can be NULL before a class is completely setup or

changeset 46427	54713555867e
parent 46329	53ccc37bda19
child 46560	388aa8d67c80