Mercurial > hg > truffle
view src/share/vm/classfile/symbolTable.hpp @ 4877:c03e06373b47
Merge
author | stefank |
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date | Sat, 28 Jan 2012 01:15:34 -0800 |
parents | 94ec88ca68e2 |
children | fc9d8850ab8b |
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/* * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP #define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP #include "memory/allocation.inline.hpp" #include "oops/symbol.hpp" #include "utilities/hashtable.hpp" // The symbol table holds all Symbol*s and corresponding interned strings. // Symbol*s and literal strings should be canonicalized. // // The interned strings are created lazily. // // It is implemented as an open hash table with a fixed number of buckets. // // %note: // - symbolTableEntrys are allocated in blocks to reduce the space overhead. class BoolObjectClosure; // Class to hold a newly created or referenced Symbol* temporarily in scope. // new_symbol() and lookup() will create a Symbol* if not already in the // symbol table and add to the symbol's reference count. // probe() and lookup_only() will increment the refcount if symbol is found. class TempNewSymbol : public StackObj { Symbol* _temp; public: TempNewSymbol() : _temp(NULL) {} // Creating or looking up a symbol increments the symbol's reference count TempNewSymbol(Symbol *s) : _temp(s) {} // Operator= increments reference count. void operator=(const TempNewSymbol &s) { _temp = s._temp; if (_temp !=NULL) _temp->increment_refcount(); } // Decrement reference counter so it can go away if it's unique ~TempNewSymbol() { if (_temp != NULL) _temp->decrement_refcount(); } // Operators so they can be used like Symbols Symbol* operator -> () const { return _temp; } bool operator == (Symbol* o) const { return _temp == o; } // Sneaky conversion function operator Symbol*() { return _temp; } }; class SymbolTable : public Hashtable<Symbol*> { friend class VMStructs; friend class ClassFileParser; private: // The symbol table static SymbolTable* _the_table; // For statistics static int symbols_removed; static int symbols_counted; Symbol* allocate_symbol(const u1* name, int len, TRAPS); // Assumes no characters larger than 0x7F bool allocate_symbols(int names_count, const u1** names, int* lengths, Symbol** syms, TRAPS); // Adding elements Symbol* basic_add(int index, u1* name, int len, unsigned int hashValue, TRAPS); bool basic_add(constantPoolHandle cp, int names_count, const char** names, int* lengths, int* cp_indices, unsigned int* hashValues, TRAPS); static void new_symbols(constantPoolHandle cp, int names_count, const char** name, int* lengths, int* cp_indices, unsigned int* hashValues, TRAPS) { add(cp, names_count, name, lengths, cp_indices, hashValues, THREAD); } // Table size enum { symbol_table_size = 20011 }; Symbol* lookup(int index, const char* name, int len, unsigned int hash); SymbolTable() : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>)) {} SymbolTable(HashtableBucket* t, int number_of_entries) : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>), t, number_of_entries) {} public: enum { symbol_alloc_batch_size = 8 }; // The symbol table static SymbolTable* the_table() { return _the_table; } static void create_table() { assert(_the_table == NULL, "One symbol table allowed."); _the_table = new SymbolTable(); } static void create_table(HashtableBucket* t, int length, int number_of_entries) { assert(_the_table == NULL, "One symbol table allowed."); assert(length == symbol_table_size * sizeof(HashtableBucket), "bad shared symbol size."); _the_table = new SymbolTable(t, number_of_entries); } static Symbol* lookup(const char* name, int len, TRAPS); // lookup only, won't add. Also calculate hash. static Symbol* lookup_only(const char* name, int len, unsigned int& hash); // Only copy to C string to be added if lookup failed. static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS); static void release(Symbol* sym); // Look up the address of the literal in the SymbolTable for this Symbol* static Symbol** lookup_symbol_addr(Symbol* sym); // jchar (utf16) version of lookups static Symbol* lookup_unicode(const jchar* name, int len, TRAPS); static Symbol* lookup_only_unicode(const jchar* name, int len, unsigned int& hash); static void add(constantPoolHandle cp, int names_count, const char** names, int* lengths, int* cp_indices, unsigned int* hashValues, TRAPS); // Release any dead symbols static void unlink(); // iterate over symbols static void symbols_do(SymbolClosure *cl); // Symbol creation static Symbol* new_symbol(const char* utf8_buffer, int length, TRAPS) { assert(utf8_buffer != NULL, "just checking"); return lookup(utf8_buffer, length, THREAD); } static Symbol* new_symbol(const char* name, TRAPS) { return new_symbol(name, (int)strlen(name), THREAD); } static Symbol* new_symbol(const Symbol* sym, int begin, int end, TRAPS) { assert(begin <= end && end <= sym->utf8_length(), "just checking"); return lookup(sym, begin, end, THREAD); } // Symbol lookup static Symbol* lookup(int index, const char* name, int len, TRAPS); // Needed for preloading classes in signatures when compiling. // Returns the symbol is already present in symbol table, otherwise // NULL. NO ALLOCATION IS GUARANTEED! static Symbol* probe(const char* name, int len) { unsigned int ignore_hash; return lookup_only(name, len, ignore_hash); } static Symbol* probe_unicode(const jchar* name, int len) { unsigned int ignore_hash; return lookup_only_unicode(name, len, ignore_hash); } // Histogram static void print_histogram() PRODUCT_RETURN; static void print() PRODUCT_RETURN; // Debugging static void verify(); // Sharing static void copy_buckets(char** top, char*end) { the_table()->Hashtable<Symbol*>::copy_buckets(top, end); } static void copy_table(char** top, char*end) { the_table()->Hashtable<Symbol*>::copy_table(top, end); } static void reverse(void* boundary = NULL) { the_table()->Hashtable<Symbol*>::reverse(boundary); } }; class StringTable : public Hashtable<oop> { friend class VMStructs; private: // The string table static StringTable* _the_table; static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS); oop basic_add(int index, Handle string_or_null, jchar* name, int len, unsigned int hashValue, TRAPS); oop lookup(int index, jchar* chars, int length, unsigned int hashValue); StringTable() : Hashtable<oop>((int)StringTableSize, sizeof (HashtableEntry<oop>)) {} StringTable(HashtableBucket* t, int number_of_entries) : Hashtable<oop>((int)StringTableSize, sizeof (HashtableEntry<oop>), t, number_of_entries) {} public: // The string table static StringTable* the_table() { return _the_table; } static void create_table() { assert(_the_table == NULL, "One string table allowed."); _the_table = new StringTable(); } static void create_table(HashtableBucket* t, int length, int number_of_entries) { assert(_the_table == NULL, "One string table allowed."); assert((size_t)length == StringTableSize * sizeof(HashtableBucket), "bad shared string size."); _the_table = new StringTable(t, number_of_entries); } // GC support // Delete pointers to otherwise-unreachable objects. static void unlink(BoolObjectClosure* cl); // Invoke "f->do_oop" on the locations of all oops in the table. static void oops_do(OopClosure* f); // Probing static oop lookup(Symbol* symbol); // Interning static oop intern(Symbol* symbol, TRAPS); static oop intern(oop string, TRAPS); static oop intern(const char *utf8_string, TRAPS); // Debugging static void verify(); // Sharing static void copy_buckets(char** top, char*end) { the_table()->Hashtable<oop>::copy_buckets(top, end); } static void copy_table(char** top, char*end) { the_table()->Hashtable<oop>::copy_table(top, end); } static void reverse() { the_table()->Hashtable<oop>::reverse(); } }; #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP