1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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   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  *
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  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
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  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 typedef struct {
  99   const char* name;                // Name of address (example: "SharedRuntime::register_finalizer")
 100   void* value;                     // Value of address
 101 } VMAddressEntry;
 102 
 103 // This class is a friend of most classes, to be able to access
 104 // private fields
 105 class VMStructs {
 106 public:
 107   // The last entry is identified over in the serviceability agent by
 108   // the fact that it has a NULL fieldName
 109   static VMStructEntry localHotSpotVMStructs[];
 110 
 111   // The last entry is identified over in the serviceability agent by
 112   // the fact that it has a NULL typeName
 113   static VMTypeEntry   localHotSpotVMTypes[];
 114 
 115   // Table of integer 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 VMIntConstantEntry localHotSpotVMIntConstants[];
 119 
 120   // Table of long constants required by the serviceability agent.
 121   // The last entry is identified over in the serviceability agent by
 122   // the fact that it has a NULL typeName
 123   static VMLongConstantEntry localHotSpotVMLongConstants[];
 124 
 125   /**
 126    * Table of addresses.
 127    */
 128   static VMAddressEntry localHotSpotVMAddresses[];
 129 
 130   // This is used to run any checking code necessary for validation of
 131   // the data structure (debug build only)
 132   static void init();
 133 
 134 #ifndef PRODUCT
 135   // Execute unit tests
 136   static void test();
 137 #endif
 138 
 139 private:
 140   // Look up a type in localHotSpotVMTypes using strcmp() (debug build only).
 141   // Returns 1 if found, 0 if not.
 142   //  debug_only(static int findType(const char* typeName);)
 143   static int findType(const char* typeName);
 144 };
 145 
 146 #endif // SHARE_VM_RUNTIME_VMSTRUCTS_HPP
--- EOF ---