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1 /* |
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2 * Copyright 2000-2001 Sun Microsystems, Inc. All Rights Reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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20 * CA 95054 USA or visit www.sun.com if you need additional information or |
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21 * have any questions. |
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22 * |
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23 */ |
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24 |
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25 // This table encapsulates the debugging information required by the |
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26 // serviceability agent in order to run. Specifically, we need to |
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27 // understand the layout of certain C data structures (offsets, in |
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28 // bytes, of their fields.) |
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29 // |
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30 // There are alternatives for the design of this mechanism, including |
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31 // parsing platform-specific debugging symbols from a debug build into |
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32 // a program database. While this current mechanism can be considered |
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33 // to be a workaround for the inability to debug arbitrary C and C++ |
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34 // programs at the present time, it does have certain advantages. |
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35 // First, it is platform-independent, which will vastly simplify the |
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36 // initial bringup of the system both now and on future platforms. |
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37 // Second, it is embedded within the VM, as opposed to being in a |
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38 // separate program database; experience has shown that whenever |
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39 // portions of a system are decoupled, version skew is problematic. |
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40 // Third, generating a program database, for example for a product |
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41 // build, would probably require two builds to be done: the desired |
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42 // product build as well as an intermediary build with the PRODUCT |
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43 // flag turned on but also compiled with -g, leading to a doubling of |
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44 // the time required to get a serviceability agent-debuggable product |
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45 // build. Fourth, and very significantly, this table probably |
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46 // preserves more information about field types than stabs do; for |
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47 // example, it preserves the fact that a field is a "jlong" rather |
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48 // than transforming the type according to the typedef in jni_md.h, |
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49 // which allows the Java-side code to identify "Java-sized" fields in |
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50 // C++ data structures. If the symbol parsing mechanism was redone |
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51 // using stabs, it might still be necessary to have a table somewhere |
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52 // containing this information. |
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53 // |
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54 // Do not change the sizes or signedness of the integer values in |
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55 // these data structures; they are fixed over in the serviceability |
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56 // agent's Java code (for bootstrapping). |
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57 |
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58 typedef struct { |
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59 const char* typeName; // The type name containing the given field (example: "Klass") |
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60 const char* fieldName; // The field name within the type (example: "_name") |
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61 const char* typeString; // Quoted name of the type of this field (example: "symbolOopDesc*"; |
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62 // parsed in Java to ensure type correctness |
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63 int32_t isStatic; // Indicates whether following field is an offset or an address |
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64 uint64_t offset; // Offset of field within structure; only used for nonstatic fields |
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65 void* address; // Address of field; only used for static fields |
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66 // ("offset" can not be reused because of apparent SparcWorks compiler bug |
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67 // in generation of initializer data) |
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68 } VMStructEntry; |
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69 |
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70 typedef struct { |
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71 const char* typeName; // Type name (example: "methodOopDesc") |
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72 const char* superclassName; // Superclass name, or null if none (example: "oopDesc") |
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73 int32_t isOopType; // Does this type represent an oop typedef? (i.e., "methodOop" or |
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74 // "klassOop", but NOT "methodOopDesc") |
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75 int32_t isIntegerType; // Does this type represent an integer type (of arbitrary size)? |
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76 int32_t isUnsigned; // If so, is it unsigned? |
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77 uint64_t size; // Size, in bytes, of the type |
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78 } VMTypeEntry; |
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79 |
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80 typedef struct { |
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81 const char* name; // Name of constant (example: "_thread_in_native") |
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82 int32_t value; // Value of constant |
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83 } VMIntConstantEntry; |
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84 |
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85 typedef struct { |
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86 const char* name; // Name of constant (example: "_thread_in_native") |
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87 uint64_t value; // Value of constant |
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88 } VMLongConstantEntry; |
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89 |
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90 // This class is a friend of most classes, to be able to access |
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91 // private fields |
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92 class VMStructs { |
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93 public: |
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94 // The last entry is identified over in the serviceability agent by |
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95 // the fact that it has a NULL fieldName |
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96 static VMStructEntry localHotSpotVMStructs[]; |
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97 |
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98 // The last entry is identified over in the serviceability agent by |
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99 // the fact that it has a NULL typeName |
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100 static VMTypeEntry localHotSpotVMTypes[]; |
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101 |
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102 // Table of integer constants required by the serviceability agent. |
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103 // The last entry is identified over in the serviceability agent by |
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104 // the fact that it has a NULL typeName |
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105 static VMIntConstantEntry localHotSpotVMIntConstants[]; |
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106 |
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107 // Table of long constants required by the serviceability agent. |
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108 // The last entry is identified over in the serviceability agent by |
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109 // the fact that it has a NULL typeName |
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110 static VMLongConstantEntry localHotSpotVMLongConstants[]; |
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111 |
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112 // This is used to run any checking code necessary for validation of |
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113 // the data structure (debug build only) |
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114 static void init(); |
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115 |
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116 private: |
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117 // Look up a type in localHotSpotVMTypes using strcmp() (debug build only). |
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118 // Returns 1 if found, 0 if not. |
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119 // debug_only(static int findType(const char* typeName);) |
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120 static int findType(const char* typeName); |
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121 }; |