1 /* 2 * Copyright (c) 2000, 2013, 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_RUNTIME_VMSTRUCTS_HPP 26 #define SHARE_VM_RUNTIME_VMSTRUCTS_HPP 27 28 #include "utilities/debug.hpp" 29 #ifdef COMPILER1 30 #include "c1/c1_Runtime1.hpp" 31 #endif 32 33 // This table encapsulates the debugging information required by the 34 // serviceability agent in order to run. Specifically, we need to 35 // understand the layout of certain C data structures (offsets, in 36 // bytes, of their fields.) 37 // 38 // There are alternatives for the design of this mechanism, including 39 // parsing platform-specific debugging symbols from a debug build into 40 // a program database. While this current mechanism can be considered 41 // to be a workaround for the inability to debug arbitrary C and C++ 42 // programs at the present time, it does have certain advantages. 43 // First, it is platform-independent, which will vastly simplify the 44 // initial bringup of the system both now and on future platforms. 45 // Second, it is embedded within the VM, as opposed to being in a 46 // separate program database; experience has shown that whenever 47 // portions of a system are decoupled, version skew is problematic. 48 // Third, generating a program database, for example for a product 49 // build, would probably require two builds to be done: the desired 50 // product build as well as an intermediary build with the PRODUCT 51 // flag turned on but also compiled with -g, leading to a doubling of 52 // the time required to get a serviceability agent-debuggable product 53 // build. Fourth, and very significantly, this table probably 54 // preserves more information about field types than stabs do; for 55 // example, it preserves the fact that a field is a "jlong" rather 56 // than transforming the type according to the typedef in jni_md.h, 57 // which allows the Java-side code to identify "Java-sized" fields in 58 // C++ data structures. If the symbol parsing mechanism was redone 59 // using stabs, it might still be necessary to have a table somewhere 60 // containing this information. 61 // 62 // Do not change the sizes or signedness of the integer values in 63 // these data structures; they are fixed over in the serviceability 64 // agent's Java code (for bootstrapping). 65 66 typedef struct { 67 const char* typeName; // The type name containing the given field (example: "Klass") 68 const char* fieldName; // The field name within the type (example: "_name") 69 const char* typeString; // Quoted name of the type of this field (example: "Symbol*"; 70 // parsed in Java to ensure type correctness 71 int32_t isStatic; // Indicates whether following field is an offset or an address 72 uint64_t offset; // Offset of field within structure; only used for nonstatic fields 73 void* address; // Address of field; only used for static fields 74 // ("offset" can not be reused because of apparent SparcWorks compiler bug 75 // in generation of initializer data) 76 } VMStructEntry; 77 78 typedef struct { 79 const char* typeName; // Type name (example: "Method") 80 const char* superclassName; // Superclass name, or null if none (example: "oopDesc") 81 int32_t isOopType; // Does this type represent an oop typedef? (i.e., "Method*" or 82 // "Klass*", but NOT "Method") 83 int32_t isIntegerType; // Does this type represent an integer type (of arbitrary size)? 84 int32_t isUnsigned; // If so, is it unsigned? 85 uint64_t size; // Size, in bytes, of the type 86 } VMTypeEntry; 87 88 typedef struct { 89 const char* name; // Name of constant (example: "_thread_in_native") 90 int32_t value; // Value of constant 91 } VMIntConstantEntry; 92 93 typedef struct { 94 const char* name; // Name of constant (example: "_thread_in_native") 95 uint64_t value; // Value of constant 96 } VMLongConstantEntry; 97 98 // This class is a friend of most classes, to be able to access 99 // private fields 100 class VMStructs { 101 public: 102 // The last entry is identified over in the serviceability agent by 103 // the fact that it has a NULL fieldName 104 static VMStructEntry localHotSpotVMStructs[]; 105 106 // The last entry is identified over in the serviceability agent by 107 // the fact that it has a NULL typeName 108 static VMTypeEntry localHotSpotVMTypes[]; 109 110 // Table of integer constants required by the serviceability agent. 111 // The last entry is identified over in the serviceability agent by 112 // the fact that it has a NULL typeName 113 static VMIntConstantEntry localHotSpotVMIntConstants[]; 114 115 // Table of long constants required by the serviceability agent. 116 // The last entry is identified over in the serviceability agent by 117 // the fact that it has a NULL typeName 118 static VMLongConstantEntry localHotSpotVMLongConstants[]; 119 120 // This is used to run any checking code necessary for validation of 121 // the data structure (debug build only) 122 static void init(); 123 124 #ifndef PRODUCT 125 // Execute unit tests 126 static void test(); 127 #endif 128 129 private: 130 // Look up a type in localHotSpotVMTypes using strcmp() (debug build only). 131 // Returns 1 if found, 0 if not. 132 // debug_only(static int findType(const char* typeName);) 133 static int findType(const char* typeName); 134 }; 135 136 #endif // SHARE_VM_RUNTIME_VMSTRUCTS_HPP 137