/*

 * Copyright 2000-2001 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// This table encapsulates the debugging information required by the

// serviceability agent in order to run. Specifically, we need to

// understand the layout of certain C data structures (offsets, in

// bytes, of their fields.)

//

// There are alternatives for the design of this mechanism, including

// parsing platform-specific debugging symbols from a debug build into

// a program database. While this current mechanism can be considered

// to be a workaround for the inability to debug arbitrary C and C++

// programs at the present time, it does have certain advantages.

// First, it is platform-independent, which will vastly simplify the

// initial bringup of the system both now and on future platforms.

// Second, it is embedded within the VM, as opposed to being in a

// separate program database; experience has shown that whenever

// portions of a system are decoupled, version skew is problematic.

// Third, generating a program database, for example for a product

// build, would probably require two builds to be done: the desired

// product build as well as an intermediary build with the PRODUCT

// flag turned on but also compiled with -g, leading to a doubling of

// the time required to get a serviceability agent-debuggable product

// build. Fourth, and very significantly, this table probably

// preserves more information about field types than stabs do; for

// example, it preserves the fact that a field is a "jlong" rather

// than transforming the type according to the typedef in jni_md.h,

// which allows the Java-side code to identify "Java-sized" fields in

// C++ data structures. If the symbol parsing mechanism was redone

// using stabs, it might still be necessary to have a table somewhere

// containing this information.

//

// Do not change the sizes or signedness of the integer values in

// these data structures; they are fixed over in the serviceability

// agent's Java code (for bootstrapping).

typedef struct {

  const char* typeName;            // The type name containing the given field (example: "Klass")

  const char* fieldName;           // The field name within the type           (example: "_name")

  const char* typeString;          // Quoted name of the type of this field (example: "symbolOopDesc*";

                                   // parsed in Java to ensure type correctness

  int32_t  isStatic;               // Indicates whether following field is an offset or an address

  uint64_t offset;                 // Offset of field within structure; only used for nonstatic fields

  void* address;                   // Address of field; only used for static fields

                                   // ("offset" can not be reused because of apparent SparcWorks compiler bug

                                   // in generation of initializer data)

} VMStructEntry;

typedef struct {

  const char* typeName;            // Type name (example: "methodOopDesc")

  const char* superclassName;      // Superclass name, or null if none (example: "oopDesc")

  int32_t isOopType;               // Does this type represent an oop typedef? (i.e., "methodOop" or

                                   // "klassOop", but NOT "methodOopDesc")

  int32_t isIntegerType;           // Does this type represent an integer type (of arbitrary size)?

  int32_t isUnsigned;              // If so, is it unsigned?

  uint64_t size;                   // Size, in bytes, of the type

} VMTypeEntry;

typedef struct {

  const char* name;                // Name of constant (example: "_thread_in_native")

  int32_t value;                   // Value of constant

} VMIntConstantEntry;

typedef struct {

  const char* name;                // Name of constant (example: "_thread_in_native")

  uint64_t value;                  // Value of constant

} VMLongConstantEntry;

// This class is a friend of most classes, to be able to access

// private fields

class VMStructs {

public:

  // The last entry is identified over in the serviceability agent by

  // the fact that it has a NULL fieldName

  static VMStructEntry localHotSpotVMStructs[];

  // The last entry is identified over in the serviceability agent by

  // the fact that it has a NULL typeName

  static VMTypeEntry   localHotSpotVMTypes[];

  // Table of integer constants required by the serviceability agent.

  // The last entry is identified over in the serviceability agent by

  // the fact that it has a NULL typeName

  static VMIntConstantEntry localHotSpotVMIntConstants[];

  // Table of long constants required by the serviceability agent.

  // The last entry is identified over in the serviceability agent by

  // the fact that it has a NULL typeName

  static VMLongConstantEntry localHotSpotVMLongConstants[];

  // This is used to run any checking code necessary for validation of

  // the data structure (debug build only)

  static void init();

private:

  // Look up a type in localHotSpotVMTypes using strcmp() (debug build only).

  // Returns 1 if found, 0 if not.

  //  debug_only(static int findType(const char* typeName);)

  static int findType(const char* typeName);

};