/*

 * Copyright (c) 1998, 2006, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

// The verifier class

class Verifier : AllStatic {

 public:

  enum { STACKMAP_ATTRIBUTE_MAJOR_VERSION = 50 };

  typedef enum { ThrowException, NoException } Mode;

  /**

   * Verify the bytecodes for a class.  If 'throw_exception' is true

   * then the appropriate VerifyError or ClassFormatError will be thrown.

   * Otherwise, no exception is thrown and the return indicates the

   * error.

   */

  static bool verify(instanceKlassHandle klass, Mode mode, bool should_verify_class, TRAPS);

  // Return false if the class is loaded by the bootstrap loader,

  // or if defineClass was called requesting skipping verification

  // -Xverify:all/none override this value

  static bool should_verify_for(oop class_loader, bool should_verify_class);

  // Relax certain verifier checks to enable some broken 1.1 apps to run on 1.2.

  static bool relax_verify_for(oop class_loader);

 private:

  static bool is_eligible_for_verification(instanceKlassHandle klass, bool should_verify_class);

  static symbolHandle inference_verify(

    instanceKlassHandle klass, char* msg, size_t msg_len, TRAPS);

};

class RawBytecodeStream;

class StackMapFrame;

class StackMapTable;

// Summary of verifier's memory usage:

// StackMapTable is stack allocated.

// StackMapFrame are resource allocated. There is one ResourceMark

// for each method.

// There is one mutable StackMapFrame (current_frame) which is updated

// by abstract bytecode interpretation. frame_in_exception_handler() returns

// a frame that has a mutable one-item stack (ready for pushing the

// catch type exception object). All the other StackMapFrame's

// are immutable (including their locals and stack arrays) after

// their constructions.

// locals/stack arrays in StackMapFrame are resource allocated.

// locals/stack arrays can be shared between StackMapFrame's, except

// the mutable StackMapFrame (current_frame).

// Care needs to be taken to make sure resource objects don't outlive

// the lifetime of their ResourceMark.

// These macros are used similarly to CHECK macros but also check

// the status of the verifier and return if that has an error.

#define CHECK_VERIFY(verifier) \

  CHECK); if ((verifier)->has_error()) return; (0

#define CHECK_VERIFY_(verifier, result) \

  CHECK_(result)); if ((verifier)->has_error()) return (result); (0

// A new instance of this class is created for each class being verified

class ClassVerifier : public StackObj {

 private:

  Thread* _thread;

  symbolHandle _exception_type;

  char* _message;

  size_t _message_buffer_len;

  void verify_method(methodHandle method, TRAPS);

  char* generate_code_data(methodHandle m, u4 code_length, TRAPS);

  void verify_exception_handler_table(u4 code_length, char* code_data, int& min, int& max, TRAPS);

  void verify_local_variable_table(u4 code_length, char* code_data, TRAPS);

  VerificationType cp_ref_index_to_type(

      int index, constantPoolHandle cp, TRAPS) {

    return cp_index_to_type(cp->klass_ref_index_at(index), cp, THREAD);

  }

  bool is_protected_access(

    instanceKlassHandle this_class, klassOop target_class,

    symbolOop field_name, symbolOop field_sig, bool is_method);

  void verify_cp_index(constantPoolHandle cp, int index, TRAPS);

  void verify_cp_type(

    int index, constantPoolHandle cp, unsigned int types, TRAPS);

  void verify_cp_class_type(int index, constantPoolHandle cp, TRAPS);

  u2 verify_stackmap_table(

    u2 stackmap_index, u2 bci, StackMapFrame* current_frame,

    StackMapTable* stackmap_table, bool no_control_flow, TRAPS);

  void verify_exception_handler_targets(

    u2 bci, bool this_uninit, StackMapFrame* current_frame,

    StackMapTable* stackmap_table, TRAPS);

  void verify_ldc(

    int opcode, u2 index, StackMapFrame *current_frame,

    constantPoolHandle cp, u2 bci, TRAPS);

  void verify_switch(

    RawBytecodeStream* bcs, u4 code_length, char* code_data,

    StackMapFrame* current_frame, StackMapTable* stackmap_table, TRAPS);

  void verify_field_instructions(

    RawBytecodeStream* bcs, StackMapFrame* current_frame,

    constantPoolHandle cp, TRAPS);

  void verify_invoke_init(

    RawBytecodeStream* bcs, VerificationType ref_class_type,

    StackMapFrame* current_frame, u4 code_length, bool* this_uninit,

    constantPoolHandle cp, TRAPS);

  void verify_invoke_instructions(

    RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,

    bool* this_uninit, VerificationType return_type,

    constantPoolHandle cp, TRAPS);

  VerificationType get_newarray_type(u2 index, u2 bci, TRAPS);

  void verify_anewarray(

    u2 index, constantPoolHandle cp, StackMapFrame* current_frame, TRAPS);

  void verify_return_value(

    VerificationType return_type, VerificationType type, u2 offset, TRAPS);

  void verify_iload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_lload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_fload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_dload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_aload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_istore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_lstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_fstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_dstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_astore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_iinc  (u2 index, StackMapFrame* current_frame, TRAPS);

  bool name_in_supers(symbolOop ref_name, instanceKlassHandle current);

  instanceKlassHandle _klass;  // the class being verified

  methodHandle        _method; // current method being verified

  VerificationType    _this_type; // the verification type of the current class

  // Some recursive calls from the verifier to the name resolver

  // can cause the current class to be re-verified and rewritten.

  // If this happens, the original verification should not continue,

  // because constant pool indexes will have changed.

  // The rewriter is preceded by the verifier.  If the verifier throws

  // an error, rewriting is prevented.  Also, rewriting always precedes

  // bytecode execution or compilation.  Thus, is_rewritten implies

  // that a class has been verified and prepared for execution.

  bool was_recursively_verified() { return _klass->is_rewritten(); }

 public:

  enum {

    BYTECODE_OFFSET = 1,

    NEW_OFFSET = 2

  };

  // constructor

  ClassVerifier(instanceKlassHandle klass, char* msg, size_t msg_len, TRAPS);

  // destructor

  ~ClassVerifier();

  Thread* thread()             { return _thread; }

  methodHandle method()        { return _method; }

  instanceKlassHandle current_class() const { return _klass; }

  VerificationType current_type() const { return _this_type; }

  // Verifies the class.  If a verify or class file format error occurs,

  // the '_exception_name' symbols will set to the exception name and

  // the message_buffer will be filled in with the exception message.

  void verify_class(TRAPS);

  // Return status modes

  symbolHandle result() const { return _exception_type; }

  bool has_error() const { return !(result().is_null()); }

  // Called when verify or class format errors are encountered.

  // May throw an exception based upon the mode.

  void verify_error(u2 offset, const char* fmt, ...);

  void verify_error(const char* fmt, ...);

  void class_format_error(const char* fmt, ...);

  void format_error_message(const char* fmt, int offset, va_list args);

  klassOop load_class(symbolHandle name, TRAPS);

  int change_sig_to_verificationType(

    SignatureStream* sig_type, VerificationType* inference_type, TRAPS);

  VerificationType cp_index_to_type(int index, constantPoolHandle cp, TRAPS) {

    return VerificationType::reference_type(

      symbolHandle(THREAD, cp->klass_name_at(index)));

  }

  static bool _verify_verbose;  // for debugging

};

inline int ClassVerifier::change_sig_to_verificationType(

    SignatureStream* sig_type, VerificationType* inference_type, TRAPS) {

  BasicType bt = sig_type->type();

  switch (bt) {

    case T_OBJECT:

    case T_ARRAY:

      {

        symbolOop name = sig_type->as_symbol(CHECK_0);

        *inference_type =

          VerificationType::reference_type(symbolHandle(THREAD, name));

        return 1;

      }

    case T_LONG:

      *inference_type = VerificationType::long_type();

      *++inference_type = VerificationType::long2_type();

      return 2;

    case T_DOUBLE:

      *inference_type = VerificationType::double_type();

      *++inference_type = VerificationType::double2_type();

      return 2;

    case T_INT:

    case T_BOOLEAN:

    case T_BYTE:

    case T_CHAR:

    case T_SHORT:

      *inference_type = VerificationType::integer_type();

      return 1;

    case T_FLOAT:

      *inference_type = VerificationType::float_type();

      return 1;

    default:

      ShouldNotReachHere();

      return 1;

  }

}