Mercurial > hg > truffle
annotate src/share/vm/prims/jniFastGetField.hpp @ 1768:6ee479178066
6979444: add command line option to print command line flags descriptions
Summary: Implementation of a nonproduct boolean flag XX:PrintFlagsWithComments
Reviewed-by: kamg, dholmes, dsamersoff
author | ikrylov |
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date | Tue, 31 Aug 2010 03:14:00 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
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0 | 1 /* |
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2 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 // Basic logic of a fast version of jni_Get<Primitive>Field: | |
26 // | |
27 // (See safepoint.hpp for a description of _safepoint_counter) | |
28 // | |
29 // load _safepoint_counter into old_counter | |
30 // IF old_counter is odd THEN | |
31 // a safepoint is going on, return jni_GetXXXField | |
32 // ELSE | |
33 // load the primitive field value into result (speculatively) | |
34 // load _safepoint_counter into new_counter | |
35 // IF (old_counter == new_counter) THEN | |
36 // no safepoint happened during the field access, return result | |
37 // ELSE | |
38 // a safepoint might have happened in-between, return jni_GetXXXField() | |
39 // ENDIF | |
40 // ENDIF | |
41 // | |
42 // LoadLoad membars to maintain the load order may be necessary | |
43 // for some platforms. | |
44 // | |
45 // The fast versions don't check for pending suspension request. | |
46 // This is fine since it's totally read-only and doesn't create new race. | |
47 // | |
48 // There is a hypothetical safepoint counter wraparound. But it's not | |
49 // a practical concern. | |
50 | |
51 class JNI_FastGetField : AllStatic { | |
52 private: | |
53 enum { LIST_CAPACITY = 40 }; // a conservative number for the number of | |
54 // speculative loads on all the platforms | |
55 static address speculative_load_pclist []; | |
56 static address slowcase_entry_pclist []; | |
57 static int count; | |
58 | |
59 static address generate_fast_get_int_field0(BasicType type); | |
60 static address generate_fast_get_float_field0(BasicType type); | |
61 | |
62 public: | |
63 #if defined(_WINDOWS) && !defined(_WIN64) | |
64 static GetBooleanField_t jni_fast_GetBooleanField_fp; | |
65 static GetByteField_t jni_fast_GetByteField_fp; | |
66 static GetCharField_t jni_fast_GetCharField_fp; | |
67 static GetShortField_t jni_fast_GetShortField_fp; | |
68 static GetIntField_t jni_fast_GetIntField_fp; | |
69 static GetLongField_t jni_fast_GetLongField_fp; | |
70 static GetFloatField_t jni_fast_GetFloatField_fp; | |
71 static GetDoubleField_t jni_fast_GetDoubleField_fp; | |
72 #endif | |
73 | |
74 static address generate_fast_get_boolean_field(); | |
75 static address generate_fast_get_byte_field(); | |
76 static address generate_fast_get_char_field(); | |
77 static address generate_fast_get_short_field(); | |
78 static address generate_fast_get_int_field(); | |
79 static address generate_fast_get_long_field(); | |
80 static address generate_fast_get_float_field(); | |
81 static address generate_fast_get_double_field(); | |
82 | |
83 // If pc is in speculative_load_pclist, return the corresponding | |
84 // slow case entry pc. Otherwise, return -1. | |
85 // This is used by signal/exception handler to handle such case: | |
86 // After an even safepoint counter is loaded and a fast field access | |
87 // is about to begin, a GC kicks in and shrinks the heap. Then the | |
88 // field access may fault. The signal/exception handler needs to | |
89 // return to the slow case. | |
90 // | |
91 // The GC may decide to temporarily stuff some bad values into handles, | |
92 // for example, for debugging purpose, in which case we need the mapping also. | |
93 static address find_slowcase_pc(address pc); | |
94 }; |