• file
• revisions
• annotate
• diff
• comparison
• raw

src/share/vm/oops/symbolOop.hpp@dd57230ba8fe (annotated)

src/share/vm/oops/symbolOop.hpp

Tue, 05 Jan 2010 15:21:25 +0100

author

twisti

date

Tue, 05 Jan 2010 15:21:25 +0100

changeset 1573

dd57230ba8fe

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6893268: additional dynamic language related optimizations in C2
Summary: C2 needs some additional optimizations to be able to handle MethodHandle invokes and invokedynamic instructions at the best performance.
Reviewed-by: kvn, never

duke@435	1	/*
twisti@1573	2	* Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// A symbolOop is a canonicalized string.
duke@435	26	// All symbolOops reside in global symbolTable.
duke@435	27	// See oopFactory::new_symbol for how to allocate a symbolOop
duke@435	28
duke@435	29	class symbolOopDesc : public oopDesc {
duke@435	30	friend class VMStructs;
duke@435	31	private:
duke@435	32	unsigned short _length; // number of UTF8 characters in the symbol
duke@435	33	jbyte _body[1];
duke@435	34
duke@435	35	enum {
duke@435	36	// max_symbol_length is constrained by type of _length
duke@435	37	max_symbol_length = (1 << 16) -1
duke@435	38	};
duke@435	39	public:
duke@435	40
duke@435	41	// Low-level access (used with care, since not GC-safe)
duke@435	42	jbyte* base() { return &_body[0]; }
duke@435	43
duke@435	44
duke@435	45	// Returns the largest size symbol we can safely hold.
duke@435	46	static int max_length() {
duke@435	47	return max_symbol_length;
duke@435	48	}
duke@435	49
duke@435	50	static int object_size(int length) {
duke@435	51	int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize;
duke@435	52	return align_object_size(size);
duke@435	53	}
duke@435	54
duke@435	55	int object_size() { return object_size(utf8_length()); }
duke@435	56
duke@435	57	int byte_at(int index) const {
duke@435	58	assert(index >=0 && index < _length, "symbol index overflow");
duke@435	59	return ((symbolOopDesc*)this)->base()[index];
duke@435	60	}
duke@435	61
duke@435	62	void byte_at_put(int index, int value) {
duke@435	63	assert(index >=0 && index < _length, "symbol index overflow");
duke@435	64	((symbolOopDesc*)this)->base()[index] = value;
duke@435	65	}
duke@435	66
duke@435	67	jbyte* bytes() { return base(); }
duke@435	68
duke@435	69	int utf8_length() const { return _length; }
duke@435	70
duke@435	71	void set_utf8_length(int len) { _length = len; }
duke@435	72
twisti@1573	73	// Compares the symbol with a string.
duke@435	74	bool equals(const char* str, int len) const;
twisti@1573	75	bool equals(const char* str) const { return equals(str, (int) strlen(str)); }
twisti@1573	76
twisti@1573	77	// Tests if the symbol starts with the given prefix.
twisti@1573	78	bool starts_with(const char* prefix, int len) const;
twisti@1573	79	bool starts_with(const char* prefix) const {
twisti@1573	80	return starts_with(prefix, (int) strlen(prefix));
twisti@1573	81	}
twisti@1573	82
twisti@1573	83	// Tests if the symbol starts with the given prefix.
twisti@1573	84	int index_of_at(int i, const char* str, int len) const;
twisti@1573	85	int index_of_at(int i, const char* str) const {
twisti@1573	86	return index_of_at(i, str, (int) strlen(str));
twisti@1573	87	}
duke@435	88
duke@435	89	// Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg
duke@435	90	// note that the ordering is not alfabetical
duke@435	91	inline int fast_compare(symbolOop other) const;
duke@435	92
duke@435	93	// Returns receiver converted to null-terminated UTF-8 string; string is
duke@435	94	// allocated in resource area, or in the char buffer provided by caller.
duke@435	95	char* as_C_string() const;
duke@435	96	char* as_C_string(char* buf, int size) const;
duke@435	97	// Use buf if needed buffer length is <= size.
duke@435	98	char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const;
duke@435	99
duke@435	100
duke@435	101	// Returns a null terminated utf8 string in a resource array
duke@435	102	char* as_utf8() const { return as_C_string(); }
duke@435	103	char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const {
duke@435	104	return as_C_string_flexible_buffer(t, buf, size);
duke@435	105	}
duke@435	106
duke@435	107	jchar* as_unicode(int& length) const;
duke@435	108
duke@435	109	// Treating this symbol as a class name, returns the Java name for the class.
duke@435	110	// String is allocated in resource area if buffer is not provided.
duke@435	111	// See Klass::external_name()
duke@435	112	const char* as_klass_external_name() const;
duke@435	113	const char* as_klass_external_name(char* buf, int size) const;
duke@435	114
duke@435	115	bool object_is_parsable() const {
duke@435	116	return (utf8_length() > 0 || (oop)this == Universe::emptySymbol());
duke@435	117	}
duke@435	118
duke@435	119	// Printing
duke@435	120	void print_symbol_on(outputStream* st = NULL);
duke@435	121	};
duke@435	122
duke@435	123
duke@435	124	// Note: this comparison is used for vtable sorting only; it doesn't matter
duke@435	125	// what order it defines, as long as it is a total, time-invariant order
duke@435	126	// Since symbolOops are in permSpace, their relative order in memory never changes,
duke@435	127	// so use address comparison for speed
duke@435	128	int symbolOopDesc::fast_compare(symbolOop other) const {
duke@435	129	return (((uintptr_t)this < (uintptr_t)other) ? -1
duke@435	130	: ((uintptr_t)this == (uintptr_t) other) ? 0 : 1);
duke@435	131	}