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src/hotspot/share/jfr/utilities/jfrBigEndian.hpp

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  1 /*
  2  * Copyright (c) 2012, 2020, 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  *

 85 inline T JfrBigEndian::read_unaligned(const address location) {
 86   assert(location != NULL, "just checking");
 87   switch (sizeof(T)) {
 88     case sizeof(u1) :
 89       return read_bytes<u1>(location);
 90     case sizeof(u2):
 91       return read_bytes<u2>(location);
 92     case sizeof(u4):
 93       return read_bytes<u4>(location);
 94     case sizeof(u8):
 95       return read_bytes<u8>(location);
 96     default:
 97       assert(false, "not reach");
 98   }
 99   return 0;
100 }
101 
102 inline bool JfrBigEndian::platform_supports_unaligned_reads(void) {
103 #if defined(IA32) || defined(AMD64) || defined(PPC) || defined(S390)
104   return true;
105 #elif defined(ARM) || defined(AARCH64)
106   return false;
107 #else
108   #warning "Unconfigured platform"
109   return false;
110 #endif
111 }
112 
113 template<typename T>
114 inline T JfrBigEndian::read(const void* location) {
115   assert(location != NULL, "just checking");
116   assert(sizeof(T) <= sizeof(u8), "no support for arbitrary sizes");
117   if (sizeof(T) == sizeof(u1)) {
118     return *(T*)location;
119   }
120   if (is_aligned(location, sizeof(T)) || platform_supports_unaligned_reads()) {
121     // fastest case
122     switch (sizeof(T)) {
123       case sizeof(u1):
124         return *(T*)location;
125       case sizeof(u2):

  1 /*
  2  * Copyright (c) 2012, 2021, 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  *

 85 inline T JfrBigEndian::read_unaligned(const address location) {
 86   assert(location != NULL, "just checking");
 87   switch (sizeof(T)) {
 88     case sizeof(u1) :
 89       return read_bytes<u1>(location);
 90     case sizeof(u2):
 91       return read_bytes<u2>(location);
 92     case sizeof(u4):
 93       return read_bytes<u4>(location);
 94     case sizeof(u8):
 95       return read_bytes<u8>(location);
 96     default:
 97       assert(false, "not reach");
 98   }
 99   return 0;
100 }
101 
102 inline bool JfrBigEndian::platform_supports_unaligned_reads(void) {
103 #if defined(IA32) || defined(AMD64) || defined(PPC) || defined(S390)
104   return true;
105 #elif defined(ARM) || defined(AARCH64) || defined(RISCV)
106   return false;
107 #else
108   #warning "Unconfigured platform"
109   return false;
110 #endif
111 }
112 
113 template<typename T>
114 inline T JfrBigEndian::read(const void* location) {
115   assert(location != NULL, "just checking");
116   assert(sizeof(T) <= sizeof(u8), "no support for arbitrary sizes");
117   if (sizeof(T) == sizeof(u1)) {
118     return *(T*)location;
119   }
120   if (is_aligned(location, sizeof(T)) || platform_supports_unaligned_reads()) {
121     // fastest case
122     switch (sizeof(T)) {
123       case sizeof(u1):
124         return *(T*)location;
125       case sizeof(u2):
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