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src/hotspot/share/classfile/symbolTable.hpp
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*** 1,7 ****
/*
! * Copyright (c) 1997, 2017, 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.
--- 1,7 ----
/*
! * Copyright (c) 1997, 2018, 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.
*** 24,50 ****
#ifndef SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
#define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
#include "memory/allocation.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 outputStream;
- class SerializeClosure;
-
// TempNewSymbol acts as a handle class in a handle/body idiom and is
// responsible for proper resource management of the body (which is a Symbol*).
// The body is resource managed by a reference counting scheme.
// TempNewSymbol can therefore be used to properly hold a newly created or referenced
// Symbol* temporarily in scope.
--- 24,38 ----
#ifndef SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
#define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
#include "memory/allocation.hpp"
+ #include "memory/padded.hpp"
#include "oops/symbol.hpp"
+ #include "utilities/concurrentHashTable.hpp"
#include "utilities/hashtable.hpp"
// TempNewSymbol acts as a handle class in a handle/body idiom and is
// responsible for proper resource management of the body (which is a Symbol*).
// The body is resource managed by a reference counting scheme.
// TempNewSymbol can therefore be used to properly hold a newly created or referenced
// Symbol* temporarily in scope.
*** 57,67 ****
// 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) {}
// Conversion from a Symbol* to a TempNewSymbol.
// Does not increment the current reference count.
TempNewSymbol(Symbol *s) : _temp(s) {}
--- 45,55 ----
// 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) {}
// Conversion from a Symbol* to a TempNewSymbol.
// Does not increment the current reference count.
TempNewSymbol(Symbol *s) : _temp(s) {}
*** 95,272 ****
bool operator == (Symbol* o) const { return _temp == o; }
operator Symbol*() { return _temp; }
};
template <class T, class N> class CompactHashtable;
! class SymbolTable : public RehashableHashtable<Symbol*, mtSymbol> {
friend class VMStructs;
friend class ClassFileParser;
private:
// The symbol table
static SymbolTable* _the_table;
// Set if one bucket is out of balance due to hash algorithm deficiency
! static bool _needs_rehashing;
! static bool _lookup_shared_first;
! // For statistics
! static int _symbols_removed;
! static int _symbols_counted;
! // shared symbol table.
! static CompactHashtable<Symbol*, char> _shared_table;
! Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F
// Adding elements
! Symbol* basic_add(int index, u1* name, int len, unsigned int hashValue,
! bool c_heap, TRAPS);
! bool basic_add(ClassLoaderData* loader_data,
! const constantPoolHandle& cp, int names_count,
! const char** names, int* lengths, int* cp_indices,
! unsigned int* hashValues, TRAPS);
static void new_symbols(ClassLoaderData* loader_data,
const constantPoolHandle& cp, int names_count,
const char** name, int* lengths,
int* cp_indices, unsigned int* hashValues,
TRAPS) {
add(loader_data, cp, names_count, name, lengths, cp_indices, hashValues, THREAD);
}
static Symbol* lookup_shared(const char* name, int len, unsigned int hash);
! Symbol* lookup_dynamic(int index, const char* name, int len, unsigned int hash);
! Symbol* lookup(int index, const char* name, int len, unsigned int hash);
!
! SymbolTable()
! : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>)) {}
!
! SymbolTable(HashtableBucket<mtSymbol>* t, int number_of_entries)
! : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>), t,
! number_of_entries) {}
// Arena for permanent symbols (null class loader) that are never unloaded
static Arena* _arena;
static Arena* arena() { return _arena; } // called for statistics
static void initialize_symbols(int arena_alloc_size = 0);
! static volatile int _parallel_claimed_idx;
- typedef SymbolTable::BucketUnlinkContext BucketUnlinkContext;
- // Release any dead symbols. Unlinked bucket entries are collected in the given
- // context to be freed later.
- // This allows multiple threads to work on the table at once.
- static void buckets_unlink(int start_idx, int end_idx, BucketUnlinkContext* context);
public:
enum {
symbol_alloc_batch_size = 8,
// Pick initial size based on java -version size measurements
! symbol_alloc_arena_size = 360*K
};
- // The symbol table
- static SymbolTable* the_table() { return _the_table; }
-
- // Size of one bucket in the string table. Used when checking for rollover.
- static uint bucket_size() { return sizeof(HashtableBucket<mtSymbol>); }
-
static void create_table() {
assert(_the_table == NULL, "One symbol table allowed.");
_the_table = new SymbolTable();
initialize_symbols(symbol_alloc_arena_size);
}
! static unsigned int hash_symbol(const char* s, int len);
! static unsigned int hash_shared_symbol(const char* s, int len);
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(ClassLoaderData* loader_data,
! const constantPoolHandle& cp, int names_count,
! const char** names, int* lengths, int* cp_indices,
! unsigned int* hashValues, TRAPS);
!
! // Release any dead symbols
! static void unlink() {
! int processed = 0;
! int removed = 0;
! unlink(&processed, &removed);
! }
! static void unlink(int* processed, int* removed);
! // Release any dead symbols, possibly parallel version
! static void possibly_parallel_unlink(int* processed, int* removed);
!
! // iterate over symbols
! static void symbols_do(SymbolClosure *cl);
! static void metaspace_pointers_do(MetaspaceClosure* it);
// 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);
}
-
// Create a symbol in the arena for symbols that are not deleted
static Symbol* new_permanent_symbol(const char* name, TRAPS);
! // 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();
- static void dump(outputStream* st, bool verbose=false);
static void read(const char* filename, TRAPS);
! // Sharing
! static void write_to_archive();
! static void serialize(SerializeClosure* soc);
! static u4 encode_shared(Symbol* sym);
! static Symbol* decode_shared(u4 offset);
!
! // Rehash the symbol table if it gets out of balance
! static void rehash_table();
! static bool needs_rehashing() { return _needs_rehashing; }
! // Parallel chunked scanning
! static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
! static int parallel_claimed_index() { return _parallel_claimed_idx; }
};
#endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
--- 83,262 ----
bool operator == (Symbol* o) const { return _temp == o; }
operator Symbol*() { return _temp; }
};
template <class T, class N> class CompactHashtable;
+ class CompactSymbolTableWriter;
+ class SerializeClosure;
+
+ class SymbolTableConfig;
+ typedef ConcurrentHashTable<Symbol*,
+ SymbolTableConfig, mtSymbol> SymbolTableHash;
! class SymbolTableCreateEntry;
!
! class SymbolTable : public CHeapObj<mtSymbol> {
friend class VMStructs;
+ friend class Symbol;
friend class ClassFileParser;
+ friend class SymbolTableConfig;
+ friend class SymbolTableCreateEntry;
private:
+ static void delete_symbol(Symbol* sym);
+ void grow(JavaThread* jt);
+ void clean_dead_entries(JavaThread* jt);
+
// The symbol table
static SymbolTable* _the_table;
+ // Shared symbol table.
+ static CompactHashtable<Symbol*, char> _shared_table;
+ static volatile bool _lookup_shared_first;
+ static volatile bool _alt_hash;
+
+ // For statistics
+ volatile size_t _symbols_removed;
+ volatile size_t _symbols_counted;
+ SymbolTableHash* _local_table;
+ size_t _current_size;
+ volatile bool _has_work;
// Set if one bucket is out of balance due to hash algorithm deficiency
! volatile bool _needs_rehashing;
! volatile size_t _items_count;
! volatile size_t _uncleaned_items_count;
! double get_load_factor();
! double get_dead_factor();
! void check_concurrent_work();
! void trigger_concurrent_work();
!
! static void item_added();
! static void item_removed();
! static void set_item_clean_count(size_t ncl);
! static void mark_item_clean_count();
!
! SymbolTable();
!
! Symbol* allocate_symbol(const char* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F
! Symbol* do_lookup(const char* name, int len, uintx hash);
! Symbol* do_add_if_needed(const char* name, int len, uintx hash, bool heap, TRAPS);
// Adding elements
! static void add(ClassLoaderData* loader_data,
! const constantPoolHandle& cp, int names_count,
! const char** names, int* lengths, int* cp_indices,
! unsigned int* hashValues, TRAPS);
static void new_symbols(ClassLoaderData* loader_data,
const constantPoolHandle& cp, int names_count,
const char** name, int* lengths,
int* cp_indices, unsigned int* hashValues,
TRAPS) {
add(loader_data, cp, names_count, name, lengths, cp_indices, hashValues, THREAD);
}
static Symbol* lookup_shared(const char* name, int len, unsigned int hash);
! Symbol* lookup_dynamic(const char* name, int len, unsigned int hash);
! Symbol* lookup_common(const char* name, int len, unsigned int hash);
// Arena for permanent symbols (null class loader) that are never unloaded
static Arena* _arena;
static Arena* arena() { return _arena; } // called for statistics
static void initialize_symbols(int arena_alloc_size = 0);
! void concurrent_work(JavaThread* jt);
! void print_table_statistics(outputStream* st, const char* table_name);
!
! void try_rehash_table();
! bool do_rehash();
public:
+ // The symbol table
+ static SymbolTable* the_table() { return _the_table; }
+ size_t table_size();
+
enum {
symbol_alloc_batch_size = 8,
// Pick initial size based on java -version size measurements
! symbol_alloc_arena_size = 360*K // TODO (revisit)
};
static void create_table() {
assert(_the_table == NULL, "One symbol table allowed.");
_the_table = new SymbolTable();
initialize_symbols(symbol_alloc_arena_size);
}
! static void unlink() {
! do_check_concurrent_work();
! }
! static void do_check_concurrent_work();
! static void do_concurrent_work(JavaThread* jt);
! static bool has_work() { return the_table()->_has_work; }
+ // Probing
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);
! // adds new symbol if not found
static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS);
// 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);
! // 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);
! }
// 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);
}
// Create a symbol in the arena for symbols that are not deleted
static Symbol* new_permanent_symbol(const char* name, TRAPS);
! // Rehash the string table if it gets out of balance
! static void rehash_table();
! static bool needs_rehashing()
! { return SymbolTable::the_table()->_needs_rehashing; }
! // Heap dumper and CDS
! static void symbols_do(SymbolClosure *cl);
! // Sharing
! private:
! static void copy_shared_symbol_table(CompactSymbolTableWriter* ch_table);
! public:
! static void write_to_archive() NOT_CDS_RETURN;
! static void serialize(SerializeClosure* soc) NOT_CDS_RETURN;
! static void metaspace_pointers_do(MetaspaceClosure* it);
+ // Jcmd
+ static void dump(outputStream* st, bool verbose=false);
// Debugging
static void verify();
static void read(const char* filename, TRAPS);
! // Histogram
! static void print_histogram() PRODUCT_RETURN;
};
#endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
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