hotspot/src/share/vm/classfile/symbolTable.hpp
changeset 8076 96d498ec7ae1
parent 7397 5b173b4ca846
child 8727 1642a45f024f
--- a/hotspot/src/share/vm/classfile/symbolTable.hpp	Thu Jan 27 13:42:28 2011 -0800
+++ b/hotspot/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();
   }
 };