1 /*
2 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_JFR_UTILITIES_JFRBIGENDIAN_HPP
26 #define SHARE_VM_JFR_UTILITIES_JFRBIGENDIAN_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/macros.hpp"
30 #ifdef TARGET_ARCH_x86
31 # include "bytes_x86.hpp"
32 #endif
33 #ifdef TARGET_ARCH_sparc
34 # include "bytes_sparc.hpp"
35 #endif
36 #ifdef TARGET_ARCH_zero
37 # include "bytes_zero.hpp"
38 #endif
39 #ifdef TARGET_ARCH_arm
40 # include "bytes_arm.hpp"
41 #endif
42 #ifdef TARGET_ARCH_ppc
43 # include "bytes_ppc.hpp"
44 #endif
45
46 #ifndef VM_LITTLE_ENDIAN
47 # define bigendian_16(x) (x)
48 # define bigendian_32(x) (x)
49 # define bigendian_64(x) (x)
50 #else
51 # define bigendian_16(x) Bytes::swap_u2(x)
52 # define bigendian_32(x) Bytes::swap_u4(x)
53 # define bigendian_64(x) Bytes::swap_u8(x)
54 #endif
55
56 class JfrBigEndian : AllStatic {
57 private:
58 template <typename T>
59 static T read_bytes(const address location);
60 template <typename T>
61 static T read_unaligned(const address location);
62 public:
63 static bool platform_supports_unaligned_reads(void);
64 static bool is_aligned(const void* location, size_t size);
65 template <typename T>
66 static T read(const void* location);
67 };
68
69 inline bool JfrBigEndian::is_aligned(const void* location, size_t size) {
70 assert(size <= sizeof(u8), "just checking");
71 if (size == sizeof(u1)) {
72 return true;
73 }
74 // check address alignment for datum access
75 return (((uintptr_t)location & (size -1)) == 0);
76 }
77
78 template <>
79 inline u1 JfrBigEndian::read_bytes(const address location) {
80 return (*location & 0xFF);
81 }
82
83 template <>
84 inline u2 JfrBigEndian::read_bytes(const address location) {
85 return Bytes::get_Java_u2(location);
86 }
87
88 template <>
89 inline u4 JfrBigEndian::read_bytes(const address location) {
90 return Bytes::get_Java_u4(location);
91 }
92
93 template <>
94 inline u8 JfrBigEndian::read_bytes(const address location) {
95 return Bytes::get_Java_u8(location);
96 }
97
98 template <typename T>
99 inline T JfrBigEndian::read_unaligned(const address location) {
100 assert(location != NULL, "just checking");
101 switch (sizeof(T)) {
102 case sizeof(u1) :
103 return read_bytes<u1>(location);
104 case sizeof(u2):
105 return read_bytes<u2>(location);
106 case sizeof(u4):
107 return read_bytes<u4>(location);
108 case sizeof(u8):
109 return read_bytes<u8>(location);
110 default:
111 assert(false, "not reach");
112 }
113 return 0;
114 }
115
116 inline bool JfrBigEndian::platform_supports_unaligned_reads(void) {
117 #if defined(IA32) || defined(AMD64) || defined(PPC) || defined(S390)
118 return true;
119 #elif defined(SPARC) || defined(ARM) || defined(AARCH64)
120 return false;
121 #else
122 #warning "Unconfigured platform"
123 return false;
124 #endif
125 }
126
127 template<typename T>
128 inline T JfrBigEndian::read(const void* location) {
129 assert(location != NULL, "just checking");
130 assert(sizeof(T) <= sizeof(u8), "no support for arbitrary sizes");
131 if (sizeof(T) == sizeof(u1)) {
132 return *(T*)location;
133 }
134 if (is_aligned(location, sizeof(T)) || platform_supports_unaligned_reads()) {
135 // fastest case
136 switch (sizeof(T)) {
137 case sizeof(u1):
138 return *(T*)location;
139 case sizeof(u2):
140 return bigendian_16(*(T*)(location));
141 case sizeof(u4):
142 return bigendian_32(*(T*)(location));
143 case sizeof(u8):
144 return bigendian_64(*(T*)(location));
145 }
146 }
147 return read_unaligned<T>((const address)location);
148 }
149
150 #endif // SHARE_VM_JFR_UTILITIES_JFRBIGENDIAN_HPP