Mercurial > hg > graal-jvmci-8
diff src/share/vm/classfile/symbolTable.hpp @ 2177:3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
author | coleenp |
---|---|
date | Thu, 27 Jan 2011 16:11:27 -0800 |
parents | f95d63e2154a |
children | 924777755fad |
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--- a/src/share/vm/classfile/symbolTable.hpp Thu Jan 27 13:42:28 2011 -0800 +++ b/src/share/vm/classfile/symbolTable.hpp Thu Jan 27 16:11:27 2011 -0800 @@ -26,11 +26,11 @@ #define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP #include "memory/allocation.inline.hpp" -#include "oops/symbolOop.hpp" +#include "oops/symbol.hpp" #include "utilities/hashtable.hpp" -// The symbol table holds all symbolOops and corresponding interned strings. -// symbolOops and literal strings should be canonicalized. +// 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. // @@ -42,32 +42,76 @@ class BoolObjectClosure; -class SymbolTable : public Hashtable { +// 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 - symbolOop basic_add(int index, u1* name, int len, + 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 }; - symbolOop lookup(int index, const char* name, int len, unsigned int hash); + Symbol* lookup(int index, const char* name, int len, unsigned int hash); SymbolTable() - : Hashtable(symbol_table_size, sizeof (HashtableEntry)) {} + : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>)) {} SymbolTable(HashtableBucket* t, int number_of_entries) - : Hashtable(symbol_table_size, sizeof (HashtableEntry), t, + : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>), t, number_of_entries) {} @@ -92,66 +136,76 @@ _the_table = new SymbolTable(t, number_of_entries); } - static symbolOop lookup(const char* name, int len, TRAPS); + static Symbol* lookup(const char* name, int len, TRAPS); // lookup only, won't add. Also calculate hash. - static symbolOop lookup_only(const char* name, int len, unsigned int& 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 symbolOop lookup(symbolHandle sym, int begin, int end, TRAPS); + static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS); + + static void release(Symbol* sym); // jchar (utf16) version of lookups - static symbolOop lookup_unicode(const jchar* name, int len, TRAPS); - static symbolOop lookup_only_unicode(const jchar* name, int len, unsigned int& hash); + 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); - // GC support - // Delete pointers to otherwise-unreachable objects. - static void unlink(BoolObjectClosure* cl) { - the_table()->Hashtable::unlink(cl); + // 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); } - - // Invoke "f->do_oop" on the locations of all oops in the table. - static void oops_do(OopClosure* f) { - the_table()->Hashtable::oops_do(f); + 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 symbolOop lookup(int index, const char* name, int len, TRAPS); + 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 symbolOop probe(const char* name, int len) { + static Symbol* probe(const char* name, int len) { unsigned int ignore_hash; return lookup_only(name, len, ignore_hash); } - static symbolOop probe_unicode(const jchar* name, int len) { + 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::copy_buckets(top, end); + the_table()->Hashtable<Symbol*>::copy_buckets(top, end); } static void copy_table(char** top, char*end) { - the_table()->Hashtable::copy_table(top, end); + the_table()->Hashtable<Symbol*>::copy_table(top, end); } static void reverse(void* boundary = NULL) { - ((Hashtable*)the_table())->reverse(boundary); + the_table()->Hashtable<Symbol*>::reverse(boundary); } }; - -class StringTable : public Hashtable { +class StringTable : public Hashtable<oop> { friend class VMStructs; private: @@ -169,10 +223,10 @@ oop lookup(int index, jchar* chars, int length, unsigned int hashValue); - StringTable() : Hashtable(string_table_size, sizeof (HashtableEntry)) {} + StringTable() : Hashtable<oop>(string_table_size, sizeof (HashtableEntry<oop>)) {} StringTable(HashtableBucket* t, int number_of_entries) - : Hashtable(string_table_size, sizeof (HashtableEntry), t, + : Hashtable<oop>(string_table_size, sizeof (HashtableEntry<oop>), t, number_of_entries) {} public: @@ -192,26 +246,20 @@ _the_table = new StringTable(t, number_of_entries); } - static int hash_string(jchar* s, int len); - // GC support // Delete pointers to otherwise-unreachable objects. - static void unlink(BoolObjectClosure* cl) { - the_table()->Hashtable::unlink(cl); - } + static void unlink(BoolObjectClosure* cl); // Invoke "f->do_oop" on the locations of all oops in the table. - static void oops_do(OopClosure* f) { - the_table()->Hashtable::oops_do(f); - } + static void oops_do(OopClosure* f); // Probing - static oop lookup(symbolOop symbol); + static oop lookup(Symbol* symbol); // Interning - static oop intern(symbolOop symbol, TRAPS); + static oop intern(Symbol* symbol, TRAPS); static oop intern(oop string, TRAPS); static oop intern(const char *utf8_string, TRAPS); @@ -220,13 +268,13 @@ // Sharing static void copy_buckets(char** top, char*end) { - the_table()->Hashtable::copy_buckets(top, end); + the_table()->Hashtable<oop>::copy_buckets(top, end); } static void copy_table(char** top, char*end) { - the_table()->Hashtable::copy_table(top, end); + the_table()->Hashtable<oop>::copy_table(top, end); } static void reverse() { - ((BasicHashtable*)the_table())->reverse(); + the_table()->Hashtable<oop>::reverse(); } };