/* * Copyright 1997-2009 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. * */ // A constantPool is an array containing class constants as described in the // class file. // // Most of the constant pool entries are written during class parsing, which // is safe. For klass and string types, the constant pool entry is // modified when the entry is resolved. If a klass or string constant pool // entry is read without a lock, only the resolved state guarantees that // the entry in the constant pool is a klass or String object and // not a symbolOop. class SymbolHashMap; class constantPoolOopDesc : public oopDesc { friend class VMStructs; friend class BytecodeInterpreter; // Directly extracts an oop in the pool for fast instanceof/checkcast private: typeArrayOop _tags; // the tag array describing the constant pool's contents constantPoolCacheOop _cache; // the cache holding interpreter runtime information klassOop _pool_holder; // the corresponding class int _flags; // a few header bits to describe contents for GC int _length; // number of elements in the array volatile bool _is_conc_safe; // if true, safe for concurrent // GC processing // only set to non-zero if constant pool is merged by RedefineClasses int _orig_length; void set_tags(typeArrayOop tags) { oop_store_without_check((oop*)&_tags, tags); } void tag_at_put(int which, jbyte t) { tags()->byte_at_put(which, t); } void release_tag_at_put(int which, jbyte t) { tags()->release_byte_at_put(which, t); } enum FlagBit { FB_has_invokedynamic = 1, FB_has_pseudo_string = 2 }; int flags() const { return _flags; } void set_flags(int f) { _flags = f; } bool flag_at(FlagBit fb) const { return (_flags & (1 << (int)fb)) != 0; } void set_flag_at(FlagBit fb); // no clear_flag_at function; they only increase private: intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); } oop* tags_addr() { return (oop*)&_tags; } oop* cache_addr() { return (oop*)&_cache; } oop* obj_at_addr(int which) const { assert(is_within_bounds(which), "index out of bounds"); return (oop*) &base()[which]; } jint* int_at_addr(int which) const { assert(is_within_bounds(which), "index out of bounds"); return (jint*) &base()[which]; } jlong* long_at_addr(int which) const { assert(is_within_bounds(which), "index out of bounds"); return (jlong*) &base()[which]; } jfloat* float_at_addr(int which) const { assert(is_within_bounds(which), "index out of bounds"); return (jfloat*) &base()[which]; } jdouble* double_at_addr(int which) const { assert(is_within_bounds(which), "index out of bounds"); return (jdouble*) &base()[which]; } public: typeArrayOop tags() const { return _tags; } bool has_pseudo_string() const { return flag_at(FB_has_pseudo_string); } bool has_invokedynamic() const { return flag_at(FB_has_invokedynamic); } void set_pseudo_string() { set_flag_at(FB_has_pseudo_string); } void set_invokedynamic() { set_flag_at(FB_has_invokedynamic); } // Klass holding pool klassOop pool_holder() const { return _pool_holder; } void set_pool_holder(klassOop k) { oop_store_without_check((oop*)&_pool_holder, (oop) k); } oop* pool_holder_addr() { return (oop*)&_pool_holder; } // Interpreter runtime support constantPoolCacheOop cache() const { return _cache; } void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); } // Assembly code support static int tags_offset_in_bytes() { return offset_of(constantPoolOopDesc, _tags); } static int cache_offset_in_bytes() { return offset_of(constantPoolOopDesc, _cache); } static int pool_holder_offset_in_bytes() { return offset_of(constantPoolOopDesc, _pool_holder); } // Storing constants void klass_at_put(int which, klassOop k) { oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); // The interpreter assumes when the tag is stored, the klass is resolved // and the klassOop is a klass rather than a symbolOop, so we need // hardware store ordering here. release_tag_at_put(which, JVM_CONSTANT_Class); if (UseConcMarkSweepGC) { // In case the earlier card-mark was consumed by a concurrent // marking thread before the tag was updated, redirty the card. oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); } } // For temporary use while constructing constant pool void klass_index_at_put(int which, int name_index) { tag_at_put(which, JVM_CONSTANT_ClassIndex); *int_at_addr(which) = name_index; } // Temporary until actual use void unresolved_klass_at_put(int which, symbolOop s) { // Overwrite the old index with a GC friendly value so // that if GC looks during the transition it won't try // to treat a small integer as oop. *obj_at_addr(which) = NULL; release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass); oop_store_without_check(obj_at_addr(which), oop(s)); } // Temporary until actual use void unresolved_string_at_put(int which, symbolOop s) { *obj_at_addr(which) = NULL; release_tag_at_put(which, JVM_CONSTANT_UnresolvedString); oop_store_without_check(obj_at_addr(which), oop(s)); } void int_at_put(int which, jint i) { tag_at_put(which, JVM_CONSTANT_Integer); *int_at_addr(which) = i; } void long_at_put(int which, jlong l) { tag_at_put(which, JVM_CONSTANT_Long); // *long_at_addr(which) = l; Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l)); } void float_at_put(int which, jfloat f) { tag_at_put(which, JVM_CONSTANT_Float); *float_at_addr(which) = f; } void double_at_put(int which, jdouble d) { tag_at_put(which, JVM_CONSTANT_Double); // *double_at_addr(which) = d; // u8 temp = *(u8*) &d; Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d)); } void symbol_at_put(int which, symbolOop s) { tag_at_put(which, JVM_CONSTANT_Utf8); oop_store_without_check(obj_at_addr(which), oop(s)); } void string_at_put(int which, oop str) { oop_store((volatile oop*)obj_at_addr(which), str); release_tag_at_put(which, JVM_CONSTANT_String); if (UseConcMarkSweepGC) { // In case the earlier card-mark was consumed by a concurrent // marking thread before the tag was updated, redirty the card. oop_store_without_check((volatile oop *)obj_at_addr(which), str); } } // For temporary use while constructing constant pool void string_index_at_put(int which, int string_index) { tag_at_put(which, JVM_CONSTANT_StringIndex); *int_at_addr(which) = string_index; } void field_at_put(int which, int class_index, int name_and_type_index) { tag_at_put(which, JVM_CONSTANT_Fieldref); *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; } void method_at_put(int which, int class_index, int name_and_type_index) { tag_at_put(which, JVM_CONSTANT_Methodref); *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; } void interface_method_at_put(int which, int class_index, int name_and_type_index) { tag_at_put(which, JVM_CONSTANT_InterfaceMethodref); *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice } void name_and_type_at_put(int which, int name_index, int signature_index) { tag_at_put(which, JVM_CONSTANT_NameAndType); *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice } // Tag query constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); } // Whether the entry is a pointer that must be GC'd. bool is_pointer_entry(int which) { constantTag tag = tag_at(which); return tag.is_klass() || tag.is_unresolved_klass() || tag.is_symbol() || tag.is_unresolved_string() || tag.is_string(); } // Fetching constants klassOop klass_at(int which, TRAPS) { constantPoolHandle h_this(THREAD, this); return klass_at_impl(h_this, which, CHECK_NULL); } symbolOop klass_name_at(int which); // Returns the name, w/o resolving. klassOop resolved_klass_at(int which) { // Used by Compiler guarantee(tag_at(which).is_klass(), "Corrupted constant pool"); // Must do an acquire here in case another thread resolved the klass // behind our back, lest we later load stale values thru the oop. return klassOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); } // This method should only be used with a cpool lock or during parsing or gc symbolOop unresolved_klass_at(int which) { // Temporary until actual use symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); // check that the klass is still unresolved. assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool"); return s; } // RedefineClasses() API support: symbolOop klass_at_noresolve(int which) { return klass_name_at(which); } jint int_at(int which) { assert(tag_at(which).is_int(), "Corrupted constant pool"); return *int_at_addr(which); } jlong long_at(int which) { assert(tag_at(which).is_long(), "Corrupted constant pool"); // return *long_at_addr(which); u8 tmp = Bytes::get_native_u8((address)&base()[which]); return *((jlong*)&tmp); } jfloat float_at(int which) { assert(tag_at(which).is_float(), "Corrupted constant pool"); return *float_at_addr(which); } jdouble double_at(int which) { assert(tag_at(which).is_double(), "Corrupted constant pool"); u8 tmp = Bytes::get_native_u8((address)&base()[which]); return *((jdouble*)&tmp); } symbolOop symbol_at(int which) { assert(tag_at(which).is_utf8(), "Corrupted constant pool"); return symbolOop(*obj_at_addr(which)); } oop string_at(int which, TRAPS) { constantPoolHandle h_this(THREAD, this); return string_at_impl(h_this, which, CHECK_NULL); } // A "pseudo-string" is an non-string oop that has found is way into // a String entry. // Under AnonymousClasses this can happen if the user patches a live // object into a CONSTANT_String entry of an anonymous class. // Method oops internally created for method handles may also // use pseudo-strings to link themselves to related metaobjects. bool is_pseudo_string_at(int which); oop pseudo_string_at(int which) { assert(tag_at(which).is_string(), "Corrupted constant pool"); return *obj_at_addr(which); } void pseudo_string_at_put(int which, oop x) { assert(AnonymousClasses, ""); set_pseudo_string(); // mark header assert(tag_at(which).is_string() || tag_at(which).is_unresolved_string(), "Corrupted constant pool"); string_at_put(which, x); // this works just fine } // only called when we are sure a string entry is already resolved (via an // earlier string_at call. oop resolved_string_at(int which) { assert(tag_at(which).is_string(), "Corrupted constant pool"); // Must do an acquire here in case another thread resolved the klass // behind our back, lest we later load stale values thru the oop. return (oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)); } // This method should only be used with a cpool lock or during parsing or gc symbolOop unresolved_string_at(int which) { // Temporary until actual use symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); // check that the string is still unresolved. assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool"); return s; } // Returns an UTF8 for a CONSTANT_String entry at a given index. // UTF8 char* representation was chosen to avoid conversion of // java_lang_Strings at resolved entries into symbolOops // or vice versa. // Caller is responsible for checking for pseudo-strings. char* string_at_noresolve(int which); jint name_and_type_at(int which) { assert(tag_at(which).is_name_and_type(), "Corrupted constant pool"); return *int_at_addr(which); } // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve, // name_and_type_ref_index_at) all expect constant pool indices // from the bytecodes to be passed in, which are actually potentially byte-swapped // or rewritten constant pool cache indices. They all call map_instruction_operand_to_index. int map_instruction_operand_to_index(int operand); // There are also "uncached" versions which do not map the operand index; see below. // Lookup for entries consisting of (klass_index, name_and_type index) klassOop klass_ref_at(int which, TRAPS); symbolOop klass_ref_at_noresolve(int which); symbolOop name_ref_at(int which) { return impl_name_ref_at(which, false); } symbolOop signature_ref_at(int which) { return impl_signature_ref_at(which, false); } int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); } int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); } // Lookup for entries consisting of (name_index, signature_index) int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt) int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt) symbolOop nt_name_ref_at(int which_nt) { return symbol_at(name_ref_index_at(which_nt)); } symbolOop nt_signature_ref_at(int which_nt) { return symbol_at(signature_ref_index_at(which_nt)); } BasicType basic_type_for_signature_at(int which); // Resolve string constants (to prevent allocation during compilation) void resolve_string_constants(TRAPS) { constantPoolHandle h_this(THREAD, this); resolve_string_constants_impl(h_this, CHECK); } // Klass name matches name at offset bool klass_name_at_matches(instanceKlassHandle k, int which); // Sizing int length() const { return _length; } void set_length(int length) { _length = length; } // Tells whether index is within bounds. bool is_within_bounds(int index) const { return 0 <= index && index < length(); } static int header_size() { return sizeof(constantPoolOopDesc)/HeapWordSize; } static int object_size(int length) { return align_object_size(header_size() + length); } int object_size() { return object_size(length()); } bool is_conc_safe() { return _is_conc_safe; } void set_is_conc_safe(bool v) { _is_conc_safe = v; } friend class constantPoolKlass; friend class ClassFileParser; friend class SystemDictionary; // Used by compiler to prevent classloading. static klassOop klass_at_if_loaded (constantPoolHandle this_oop, int which); static klassOop klass_ref_at_if_loaded (constantPoolHandle this_oop, int which); // Same as above - but does LinkResolving. static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS); // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the // future by other Java code. These take constant pool indices rather than possibly-byte-swapped // constant pool cache indices as do the peer methods above. symbolOop uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); } symbolOop uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); } int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); } int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); } // Sharing int pre_resolve_shared_klasses(TRAPS); void shared_symbols_iterate(OopClosure* closure0); void shared_tags_iterate(OopClosure* closure0); void shared_strings_iterate(OopClosure* closure0); // Debugging const char* printable_name_at(int which) PRODUCT_RETURN0; private: symbolOop impl_name_ref_at(int which, bool uncached); symbolOop impl_signature_ref_at(int which, bool uncached); int impl_klass_ref_index_at(int which, bool uncached); int impl_name_and_type_ref_index_at(int which, bool uncached); // Takes either a constant pool cache index in possibly byte-swapped // byte order (which comes from the bytecodes after rewriting) or, // if "uncached" is true, a vanilla constant pool index jint field_or_method_at(int which, bool uncached) { int i = which; if (!uncached && cache() != NULL) { // change byte-ordering and go via cache i = map_instruction_operand_to_index(which); } assert(tag_at(i).is_field_or_method(), "Corrupted constant pool"); return *int_at_addr(i); } // Used while constructing constant pool (only by ClassFileParser) jint klass_index_at(int which) { assert(tag_at(which).is_klass_index(), "Corrupted constant pool"); return *int_at_addr(which); } jint string_index_at(int which) { assert(tag_at(which).is_string_index(), "Corrupted constant pool"); return *int_at_addr(which); } // Performs the LinkResolver checks static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS); // Implementation of methods that needs an exposed 'this' pointer, in order to // handle GC while executing the method static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS); static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS); // Resolve string constants (to prevent allocation during compilation) static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS); public: // Merging constantPoolOop support: bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS); void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS); void copy_entry_to(int from_i, constantPoolHandle to_cp, int to_i, TRAPS); int find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS); int orig_length() const { return _orig_length; } void set_orig_length(int orig_length) { _orig_length = orig_length; } // JVMTI accesss - GetConstantPool, RetransformClasses, ... friend class JvmtiConstantPoolReconstituter; private: jint cpool_entry_size(jint idx); jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap); // Copy cpool bytes into byte array. // Returns: // int > 0, count of the raw cpool bytes that have been copied // 0, OutOfMemory error // -1, Internal error int copy_cpool_bytes(int cpool_size, SymbolHashMap* tbl, unsigned char *bytes); }; class SymbolHashMapEntry : public CHeapObj { private: unsigned int _hash; // 32-bit hash for item SymbolHashMapEntry* _next; // Next element in the linked list for this bucket symbolOop _symbol; // 1-st part of the mapping: symbol => value u2 _value; // 2-nd part of the mapping: symbol => value public: unsigned int hash() const { return _hash; } void set_hash(unsigned int hash) { _hash = hash; } SymbolHashMapEntry* next() const { return _next; } void set_next(SymbolHashMapEntry* next) { _next = next; } symbolOop symbol() const { return _symbol; } void set_symbol(symbolOop sym) { _symbol = sym; } u2 value() const { return _value; } void set_value(u2 value) { _value = value; } SymbolHashMapEntry(unsigned int hash, symbolOop symbol, u2 value) : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {} }; // End SymbolHashMapEntry class class SymbolHashMapBucket : public CHeapObj { private: SymbolHashMapEntry* _entry; public: SymbolHashMapEntry* entry() const { return _entry; } void set_entry(SymbolHashMapEntry* entry) { _entry = entry; } void clear() { _entry = NULL; } }; // End SymbolHashMapBucket class class SymbolHashMap: public CHeapObj { private: // Default number of entries in the table enum SymbolHashMap_Constants { _Def_HashMap_Size = 256 }; int _table_size; SymbolHashMapBucket* _buckets; void initialize_table(int table_size) { _table_size = table_size; _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size); for (int index = 0; index < table_size; index++) { _buckets[index].clear(); } } public: int table_size() const { return _table_size; } SymbolHashMap() { initialize_table(_Def_HashMap_Size); } SymbolHashMap(int table_size) { initialize_table(table_size); } // hash P(31) from Kernighan & Ritchie static unsigned int compute_hash(const char* str, int len) { unsigned int hash = 0; while (len-- > 0) { hash = 31*hash + (unsigned) *str; str++; } return hash; } SymbolHashMapEntry* bucket(int i) { return _buckets[i].entry(); } void add_entry(symbolOop sym, u2 value); SymbolHashMapEntry* find_entry(symbolOop sym); u2 symbol_to_value(symbolOop sym) { SymbolHashMapEntry *entry = find_entry(sym); return (entry == NULL) ? 0 : entry->value(); } ~SymbolHashMap() { SymbolHashMapEntry* next; for (int i = 0; i < _table_size; i++) { for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) { next = cur->next(); delete(cur); } } delete _buckets; } }; // End SymbolHashMap class