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

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  * published by the Free Software Foundation.

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  * 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).

  *

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

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 #ifndef SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP

 #define SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP

 #include "classfile/verificationType.hpp"

 #include "classfile/verifier.hpp"

 #include "oops/method.hpp"

 #include "runtime/handles.hpp"

 #include "runtime/signature.hpp"

 #include "utilities/exceptions.hpp"

 // A StackMapFrame represents one frame in the stack map attribute.

 class TypeContext;

 enum {

   FLAG_THIS_UNINIT = 0x01

 };

 class StackMapFrame : public ResourceObj {

  private:

   int32_t _offset;

   // See comment in StackMapTable about _frame_count about why these

   // fields are int32_t instead of u2.

   int32_t _locals_size;  // number of valid type elements in _locals

   int32_t _stack_size;   // number of valid type elements in _stack

   int32_t _stack_mark;   // Records the size of the stack prior to an

                          // instruction modification, to allow rewinding

                          // when/if an error occurs.

   int32_t _max_locals;

   int32_t _max_stack;

   u1 _flags;

   VerificationType* _locals; // local variable type array

   VerificationType* _stack;  // operand stack type array

   ClassVerifier* _verifier;  // the verifier verifying this method

   StackMapFrame(const StackMapFrame& cp) :

       _offset(cp._offset), _locals_size(cp._locals_size),

       _stack_size(cp._stack_size), _stack_mark(cp._stack_mark),

       _max_locals(cp._max_locals), _max_stack(cp._max_stack),

       _flags(cp._flags) {

     _locals = NEW_RESOURCE_ARRAY(VerificationType, _max_locals);

     for (int i = 0; i < _max_locals; ++i) {

       if (i < _locals_size) {

         _locals[i] = cp._locals[i];

       } else {

         _locals[i] = VerificationType::bogus_type();

       }

     }

     int ss = MAX2(_stack_size, _stack_mark);

     _stack = NEW_RESOURCE_ARRAY(VerificationType, _max_stack);

     for (int i = 0; i < _max_stack; ++i) {

       if (i < ss) {

         _stack[i] = cp._stack[i];

       } else {

         _stack[i] = VerificationType::bogus_type();

       }

     }

     _verifier = NULL;

   }

  public:

   // constructors

   // This constructor is used by the type checker to allocate frames

   // in type state, which have _max_locals and _max_stack array elements

   // in _locals and _stack.

   StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* verifier);

   // This constructor is used to initialize stackmap frames in stackmap table,

   // which have _locals_size and _stack_size array elements in _locals and _stack.

   StackMapFrame(int32_t offset,

                 u1 flags,

                 u2 locals_size,

                 u2 stack_size,

                 u2 max_locals,

                 u2 max_stack,

                 VerificationType* locals,

                 VerificationType* stack,

                 ClassVerifier* v) : _offset(offset), _flags(flags),

                                     _locals_size(locals_size),

                                     _stack_size(stack_size),

                                     _stack_mark(-1),

                                     _max_locals(max_locals),

                                     _max_stack(max_stack),

                                     _locals(locals), _stack(stack),

                                     _verifier(v) { }

   static StackMapFrame* copy(StackMapFrame* smf) {

     return new StackMapFrame(*smf);

   }

   inline void set_offset(int32_t offset)      { _offset = offset; }

   inline void set_verifier(ClassVerifier* v)  { _verifier = v; }

   inline void set_flags(u1 flags)             { _flags = flags; }

   inline void set_locals_size(u2 locals_size) { _locals_size = locals_size; }

   inline void set_stack_size(u2 stack_size)   { _stack_size = _stack_mark = stack_size; }

   inline void clear_stack()                   { _stack_size = 0; }

   inline int32_t offset()   const             { return _offset; }

   inline ClassVerifier* verifier() const      { return _verifier; }

   inline u1 flags() const                     { return _flags; }

   inline int32_t locals_size() const          { return _locals_size; }

   inline VerificationType* locals() const     { return _locals; }

   inline int32_t stack_size() const           { return _stack_size; }

   inline VerificationType* stack() const      { return _stack; }

   inline int32_t max_locals() const           { return _max_locals; }

   inline int32_t max_stack() const            { return _max_stack; }

   inline bool flag_this_uninit() const        { return _flags & FLAG_THIS_UNINIT; }

   // Set locals and stack types to bogus

   inline void reset() {

     int32_t i;

     for (i = 0; i < _max_locals; i++) {

       _locals[i] = VerificationType::bogus_type();

     }

     for (i = 0; i < _max_stack; i++) {

       _stack[i] = VerificationType::bogus_type();

     }

   }

   // Return a StackMapFrame with the same local variable array and empty stack.

   // Stack array is allocate with unused one element.

   StackMapFrame* frame_in_exception_handler(u1 flags);

   // Set local variable type array based on m's signature.

   VerificationType set_locals_from_arg(

     const methodHandle m, VerificationType thisKlass, TRAPS);

   // Search local variable type array and stack type array.

   // Set every element with type of old_object to new_object.

   void initialize_object(

     VerificationType old_object, VerificationType new_object);

   // Copy local variable type array in src into this local variable type array.

   void copy_locals(const StackMapFrame* src);

   // Copy stack type array in src into this stack type array.

   void copy_stack(const StackMapFrame* src);

   // Return true if this stack map frame is assignable to target.

   bool is_assignable_to(

       const StackMapFrame* target, ErrorContext* ctx, TRAPS) const;

   inline void set_mark() {

 #ifdef ASSERT

     // Put bogus type to indicate it's no longer valid.

     if (_stack_mark != -1) {

       for (int i = _stack_mark - 1; i >= _stack_size; --i) {

         _stack[i] = VerificationType::bogus_type();

       }

     }

 #endif // def ASSERT

     _stack_mark = _stack_size;

   }

   // Used when an error occurs and we want to reset the stack to the state

   // it was before operands were popped off.

   void restore() {

     if (_stack_mark != -1) {

       _stack_size = _stack_mark;

     }

   }

   // Push type into stack type array.

   inline void push_stack(VerificationType type, TRAPS) {

     assert(!type.is_check(), "Must be a real type");

     if (_stack_size >= _max_stack) {

       verifier()->verify_error(

           ErrorContext::stack_overflow(_offset, this),

           "Operand stack overflow");

       return;

     }

     _stack[_stack_size++] = type;

   }

   inline void push_stack_2(

       VerificationType type1, VerificationType type2, TRAPS) {

     assert(type1.is_long() || type1.is_double(), "must be long/double");

     assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");

     if (_stack_size >= _max_stack - 1) {

       verifier()->verify_error(

           ErrorContext::stack_overflow(_offset, this),

           "Operand stack overflow");

       return;

     }

     _stack[_stack_size++] = type1;

     _stack[_stack_size++] = type2;

   }

   // Pop and return the top type on stack without verifying.

   inline VerificationType pop_stack(TRAPS) {

     if (_stack_size <= 0) {

       verifier()->verify_error(

           ErrorContext::stack_underflow(_offset, this),

           "Operand stack underflow");

       return VerificationType::bogus_type();

     }

     VerificationType top = _stack[--_stack_size];

     return top;

   }

   // Pop and return the top type on stack type array after verifying it

   // is assignable to type.

   inline VerificationType pop_stack(VerificationType type, TRAPS) {

     if (_stack_size != 0) {

       VerificationType top = _stack[_stack_size - 1];

       bool subtype = type.is_assignable_from(

         top, verifier(), false, CHECK_(VerificationType::bogus_type()));

       if (subtype) {

         --_stack_size;

         return top;

       }

     }

     return pop_stack_ex(type, THREAD);

   }

   inline void pop_stack_2(

       VerificationType type1, VerificationType type2, TRAPS) {

     assert(type1.is_long2() || type1.is_double2(), "must be long/double");

     assert(type2.is_long() || type2.is_double(), "must be long/double_2");

     if (_stack_size >= 2) {

       VerificationType top1 = _stack[_stack_size - 1];

       bool subtype1 = type1.is_assignable_from(top1, verifier(), false, CHECK);

       VerificationType top2 = _stack[_stack_size - 2];

       bool subtype2 = type2.is_assignable_from(top2, verifier(), false, CHECK);

       if (subtype1 && subtype2) {

         _stack_size -= 2;

         return;

       }

     }

     pop_stack_ex(type1, THREAD);

     pop_stack_ex(type2, THREAD);

   }

   VerificationType local_at(int index) {

     return _locals[index];

   }

   VerificationType stack_at(int index) {

     return _stack[index];

   }

   // Uncommon case that throws exceptions.

   VerificationType pop_stack_ex(VerificationType type, TRAPS);

   // Return the type at index in local variable array after verifying

   // it is assignable to type.

   VerificationType get_local(int32_t index, VerificationType type, TRAPS);

   // For long/double.

   void get_local_2(

     int32_t index, VerificationType type1, VerificationType type2, TRAPS);

   // Set element at index in local variable array to type.

   void set_local(int32_t index, VerificationType type, TRAPS);

   // For long/double.

   void set_local_2(

     int32_t index, VerificationType type1, VerificationType type2, TRAPS);

   // Private auxiliary method used only in is_assignable_to(StackMapFrame).

   // Returns true if src is assignable to target.

   int is_assignable_to(

     VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;

   TypeOrigin stack_top_ctx();

   void print_on(outputStream* str) const;

 };

 #endif // SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP