Mercurial > hg > graal-compiler
diff src/share/vm/prims/jniFastGetField.hpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/prims/jniFastGetField.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,94 @@ +/* + * Copyright 2004 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// Basic logic of a fast version of jni_Get<Primitive>Field: +// +// (See safepoint.hpp for a description of _safepoint_counter) +// +// load _safepoint_counter into old_counter +// IF old_counter is odd THEN +// a safepoint is going on, return jni_GetXXXField +// ELSE +// load the primitive field value into result (speculatively) +// load _safepoint_counter into new_counter +// IF (old_counter == new_counter) THEN +// no safepoint happened during the field access, return result +// ELSE +// a safepoint might have happened in-between, return jni_GetXXXField() +// ENDIF +// ENDIF +// +// LoadLoad membars to maintain the load order may be necessary +// for some platforms. +// +// The fast versions don't check for pending suspension request. +// This is fine since it's totally read-only and doesn't create new race. +// +// There is a hypothetical safepoint counter wraparound. But it's not +// a practical concern. + +class JNI_FastGetField : AllStatic { + private: + enum { LIST_CAPACITY = 40 }; // a conservative number for the number of + // speculative loads on all the platforms + static address speculative_load_pclist []; + static address slowcase_entry_pclist []; + static int count; + + static address generate_fast_get_int_field0(BasicType type); + static address generate_fast_get_float_field0(BasicType type); + + public: +#if defined(_WINDOWS) && !defined(_WIN64) + static GetBooleanField_t jni_fast_GetBooleanField_fp; + static GetByteField_t jni_fast_GetByteField_fp; + static GetCharField_t jni_fast_GetCharField_fp; + static GetShortField_t jni_fast_GetShortField_fp; + static GetIntField_t jni_fast_GetIntField_fp; + static GetLongField_t jni_fast_GetLongField_fp; + static GetFloatField_t jni_fast_GetFloatField_fp; + static GetDoubleField_t jni_fast_GetDoubleField_fp; +#endif + + static address generate_fast_get_boolean_field(); + static address generate_fast_get_byte_field(); + static address generate_fast_get_char_field(); + static address generate_fast_get_short_field(); + static address generate_fast_get_int_field(); + static address generate_fast_get_long_field(); + static address generate_fast_get_float_field(); + static address generate_fast_get_double_field(); + + // If pc is in speculative_load_pclist, return the corresponding + // slow case entry pc. Otherwise, return -1. + // This is used by signal/exception handler to handle such case: + // After an even safepoint counter is loaded and a fast field access + // is about to begin, a GC kicks in and shrinks the heap. Then the + // field access may fault. The signal/exception handler needs to + // return to the slow case. + // + // The GC may decide to temporarily stuff some bad values into handles, + // for example, for debugging purpose, in which case we need the mapping also. + static address find_slowcase_pc(address pc); +};