1 /*
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   6  * under the terms of the GNU General Public License version 2 only, as
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  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).
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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 // This utility macro quotes the passed string
 147 #define QUOTE(x) #x
 148 
 149 //--------------------------------------------------------------------------------
 150 // VMStructEntry macros
 151 //
 152 
 153 // This macro generates a VMStructEntry line for a nonstatic field
 154 #define GENERATE_NONSTATIC_VM_STRUCT_ENTRY(typeName, fieldName, type)              \
 155  { QUOTE(typeName), QUOTE(fieldName), QUOTE(type), 0, offset_of(typeName, fieldName), NULL },
 156 
 157 // This macro generates a VMStructEntry line for a static field
 158 #define GENERATE_STATIC_VM_STRUCT_ENTRY(typeName, fieldName, type)                 \
 159  { QUOTE(typeName), QUOTE(fieldName), QUOTE(type), 1, 0, &typeName::fieldName },
 160 
 161 // This macro generates a VMStructEntry line for a static pointer volatile field,
 162 // e.g.: "static ObjectMonitor * volatile gBlockList;"
 163 #define GENERATE_STATIC_PTR_VOLATILE_VM_STRUCT_ENTRY(typeName, fieldName, type)    \
 164  { QUOTE(typeName), QUOTE(fieldName), QUOTE(type), 1, 0, (void *)&typeName::fieldName },
 165 
 166 // This macro generates a VMStructEntry line for an unchecked
 167 // nonstatic field, in which the size of the type is also specified.
 168 // The type string is given as NULL, indicating an "opaque" type.
 169 #define GENERATE_UNCHECKED_NONSTATIC_VM_STRUCT_ENTRY(typeName, fieldName, size)    \
 170   { QUOTE(typeName), QUOTE(fieldName), NULL, 0, offset_of(typeName, fieldName), NULL },
 171 
 172 // This macro generates a VMStructEntry line for an unchecked
 173 // static field, in which the size of the type is also specified.
 174 // The type string is given as NULL, indicating an "opaque" type.
 175 #define GENERATE_UNCHECKED_STATIC_VM_STRUCT_ENTRY(typeName, fieldName, size)       \
 176  { QUOTE(typeName), QUOTE(fieldName), NULL, 1, 0, (void*) &typeName::fieldName },
 177 
 178 // This macro generates the sentinel value indicating the end of the list
 179 #define GENERATE_VM_STRUCT_LAST_ENTRY() \
 180  { NULL, NULL, NULL, 0, 0, NULL }
 181 
 182 // This macro checks the type of a VMStructEntry by comparing pointer types
 183 #define CHECK_NONSTATIC_VM_STRUCT_ENTRY(typeName, fieldName, type)                 \
 184  {typeName *dummyObj = NULL; type* dummy = &dummyObj->fieldName;                   \
 185   assert(offset_of(typeName, fieldName) < sizeof(typeName), "Illegal nonstatic struct entry, field offset too large"); }
 186 
 187 // This macro checks the type of a volatile VMStructEntry by comparing pointer types
 188 #define CHECK_VOLATILE_NONSTATIC_VM_STRUCT_ENTRY(typeName, fieldName, type)        \
 189  {typedef type dummyvtype; typeName *dummyObj = NULL; volatile dummyvtype* dummy = &dummyObj->fieldName; }
 190 
 191 // This macro checks the type of a static VMStructEntry by comparing pointer types
 192 #define CHECK_STATIC_VM_STRUCT_ENTRY(typeName, fieldName, type)                    \
 193  {type* dummy = &typeName::fieldName; }
 194 
 195 // This macro checks the type of a static pointer volatile VMStructEntry by comparing pointer types,
 196 // e.g.: "static ObjectMonitor * volatile gBlockList;"
 197 #define CHECK_STATIC_PTR_VOLATILE_VM_STRUCT_ENTRY(typeName, fieldName, type)       \
 198  {type volatile * dummy = &typeName::fieldName; }
 199 
 200 // This macro ensures the type of a field and its containing type are
 201 // present in the type table. The assertion string is shorter than
 202 // preferable because (incredibly) of a bug in Solstice NFS client
 203 // which seems to prevent very long lines from compiling. This assertion
 204 // means that an entry in VMStructs::localHotSpotVMStructs[] was not
 205 // found in VMStructs::localHotSpotVMTypes[].
 206 #define ENSURE_FIELD_TYPE_PRESENT(typeName, fieldName, type)                       \
 207  { assert(findType(QUOTE(typeName)) != 0, "type \"" QUOTE(typeName) "\" not found in type table"); \
 208    assert(findType(QUOTE(type)) != 0, "type \"" QUOTE(type) "\" not found in type table"); }
 209 
 210 // This is a no-op macro for unchecked fields
 211 #define CHECK_NO_OP(a, b, c)
 212 
 213 
 214 //--------------------------------------------------------------------------------
 215 // VMTypeEntry macros
 216 //
 217 
 218 #define GENERATE_VM_TYPE_ENTRY(type, superclass) \
 219  { QUOTE(type), QUOTE(superclass), 0, 0, 0, sizeof(type) },
 220 
 221 #define GENERATE_TOPLEVEL_VM_TYPE_ENTRY(type) \
 222  { QUOTE(type), NULL,              0, 0, 0, sizeof(type) },
 223 
 224 #define GENERATE_OOP_VM_TYPE_ENTRY(type) \
 225  { QUOTE(type), NULL,              1, 0, 0, sizeof(type) },
 226 
 227 #define GENERATE_INTEGER_VM_TYPE_ENTRY(type) \
 228  { QUOTE(type), NULL,              0, 1, 0, sizeof(type) },
 229 
 230 #define GENERATE_UNSIGNED_INTEGER_VM_TYPE_ENTRY(type) \
 231  { QUOTE(type), NULL,              0, 1, 1, sizeof(type) },
 232 
 233 #define GENERATE_VM_TYPE_LAST_ENTRY() \
 234  { NULL, NULL, 0, 0, 0, 0 }
 235 
 236 #define CHECK_VM_TYPE_ENTRY(type, superclass) \
 237  { type* dummyObj = NULL; superclass* dummySuperObj = dummyObj; }
 238 
 239 #define CHECK_VM_TYPE_NO_OP(a)
 240 #define CHECK_SINGLE_ARG_VM_TYPE_NO_OP(a)
 241 
 242 
 243 //--------------------------------------------------------------------------------
 244 // VMIntConstantEntry macros
 245 //
 246 
 247 #define GENERATE_VM_INT_CONSTANT_ENTRY(name) \
 248  { QUOTE(name), (int32_t) name },
 249 
 250 #define GENERATE_VM_INT_CONSTANT_WITH_VALUE_ENTRY(name, value) \
 251  { (name), (int32_t)(value) },
 252 
 253 #define GENERATE_PREPROCESSOR_VM_INT_CONSTANT_ENTRY(name, value) \
 254  { name, (int32_t) value },
 255 
 256 // This macro generates the sentinel value indicating the end of the list
 257 #define GENERATE_VM_INT_CONSTANT_LAST_ENTRY() \
 258  { NULL, 0 }
 259 
 260 
 261 //--------------------------------------------------------------------------------
 262 // VMLongConstantEntry macros
 263 //
 264 
 265 #define GENERATE_VM_LONG_CONSTANT_ENTRY(name) \
 266   { QUOTE(name), name },
 267 
 268 #define GENERATE_PREPROCESSOR_VM_LONG_CONSTANT_ENTRY(name, value) \
 269   { name, value },
 270 
 271 // This macro generates the sentinel value indicating the end of the list
 272 #define GENERATE_VM_LONG_CONSTANT_LAST_ENTRY() \
 273  { NULL, 0 }
 274 
 275 
 276 //--------------------------------------------------------------------------------
 277 // VMAddressEntry macros
 278 //
 279 
 280 #define GENERATE_VM_ADDRESS_ENTRY(name) \
 281   { QUOTE(name), (void*) (name) },
 282 
 283 #define GENERATE_PREPROCESSOR_VM_ADDRESS_ENTRY(name, value) \
 284   { name, (void*) (value) },
 285 
 286 #define GENERATE_VM_FUNCTION_ENTRY(name) \
 287   { QUOTE(name), CAST_FROM_FN_PTR(void*, &(name)) },
 288 
 289 // This macro generates the sentinel value indicating the end of the list
 290 #define GENERATE_VM_ADDRESS_LAST_ENTRY() \
 291  { NULL, NULL }
 292 
 293 #endif // SHARE_VM_RUNTIME_VMSTRUCTS_HPP