duke@435: /*
duke@435:  * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // A StackMapFrame represents one frame in the stack map attribute.
duke@435: 
duke@435: enum {
duke@435:   FLAG_THIS_UNINIT = 0x01
duke@435: };
duke@435: 
duke@435: class StackMapFrame : public ResourceObj {
duke@435:  private:
duke@435:   int32_t _offset;
duke@435: 
duke@435:   // See comment in StackMapTable about _frame_count about why these
duke@435:   // fields are int32_t instead of u2.
duke@435:   int32_t _locals_size;  // number of valid type elements in _locals
duke@435:   int32_t _stack_size;   // number of valid type elements in _stack
duke@435: 
duke@435:   int32_t _max_locals;
duke@435:   int32_t _max_stack;
duke@435: 
duke@435:   u1 _flags;
duke@435:   VerificationType* _locals; // local variable type array
duke@435:   VerificationType* _stack;  // operand stack type array
duke@435: 
duke@435:   ClassVerifier* _verifier;  // the verifier verifying this method
duke@435: 
duke@435:  public:
duke@435:   // constructors
duke@435: 
duke@435:   // This constructor is used by the type checker to allocate frames
duke@435:   // in type state, which have _max_locals and _max_stack array elements
duke@435:   // in _locals and _stack.
duke@435:   StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* verifier);
duke@435: 
duke@435:   // This constructor is used to initialize stackmap frames in stackmap table,
duke@435:   // which have _locals_size and _stack_size array elements in _locals and _stack.
duke@435:   StackMapFrame(int32_t offset,
duke@435:                 u1 flags,
duke@435:                 u2 locals_size,
duke@435:                 u2 stack_size,
duke@435:                 u2 max_locals,
duke@435:                 u2 max_stack,
duke@435:                 VerificationType* locals,
duke@435:                 VerificationType* stack,
duke@435:                 ClassVerifier* v) : _offset(offset), _flags(flags),
duke@435:                                     _locals_size(locals_size),
duke@435:                                     _stack_size(stack_size),
duke@435:                                     _max_locals(max_locals),
duke@435:                                     _max_stack(max_stack),
duke@435:                                     _locals(locals), _stack(stack),
duke@435:                                     _verifier(v) { }
duke@435: 
duke@435:   inline void set_offset(int32_t offset)      { _offset = offset; }
duke@435:   inline void set_verifier(ClassVerifier* v)  { _verifier = v; }
duke@435:   inline void set_flags(u1 flags)             { _flags = flags; }
duke@435:   inline void set_locals_size(u2 locals_size) { _locals_size = locals_size; }
duke@435:   inline void set_stack_size(u2 stack_size)   { _stack_size = stack_size; }
duke@435:   inline void clear_stack()                   { _stack_size = 0; }
duke@435:   inline int32_t offset()   const             { return _offset; }
duke@435:   inline ClassVerifier* verifier() const      { return _verifier; }
duke@435:   inline u1 flags() const                     { return _flags; }
duke@435:   inline int32_t locals_size() const          { return _locals_size; }
duke@435:   inline VerificationType* locals() const     { return _locals; }
duke@435:   inline int32_t stack_size() const           { return _stack_size; }
duke@435:   inline VerificationType* stack() const      { return _stack; }
duke@435:   inline int32_t max_locals() const           { return _max_locals; }
duke@435:   inline int32_t max_stack() const            { return _max_stack; }
duke@435:   inline bool flag_this_uninit() const        { return _flags & FLAG_THIS_UNINIT; }
duke@435: 
duke@435:   // Set locals and stack types to bogus
duke@435:   inline void reset() {
duke@435:     int32_t i;
duke@435:     for (i = 0; i < _max_locals; i++) {
duke@435:       _locals[i] = VerificationType::bogus_type();
duke@435:     }
duke@435:     for (i = 0; i < _max_stack; i++) {
duke@435:       _stack[i] = VerificationType::bogus_type();
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // Return a StackMapFrame with the same local variable array and empty stack.
duke@435:   // Stack array is allocate with unused one element.
duke@435:   StackMapFrame* frame_in_exception_handler(u1 flags);
duke@435: 
duke@435:   // Set local variable type array based on m's signature.
duke@435:   VerificationType set_locals_from_arg(
duke@435:     const methodHandle m, VerificationType thisKlass, TRAPS);
duke@435: 
duke@435:   // Search local variable type array and stack type array.
duke@435:   // Return true if an uninitialized object is found.
duke@435:   bool has_new_object() const;
duke@435: 
duke@435:   // Search local variable type array and stack type array.
duke@435:   // Set every element with type of old_object to new_object.
duke@435:   void initialize_object(
duke@435:     VerificationType old_object, VerificationType new_object);
duke@435: 
duke@435:   // Copy local variable type array in src into this local variable type array.
duke@435:   void copy_locals(const StackMapFrame* src);
duke@435: 
duke@435:   // Copy stack type array in src into this stack type array.
duke@435:   void copy_stack(const StackMapFrame* src);
duke@435: 
duke@435:   // Return true if this stack map frame is assignable to target.
duke@435:   bool is_assignable_to(const StackMapFrame* target, TRAPS) const;
duke@435: 
duke@435:   // Push type into stack type array.
duke@435:   inline void push_stack(VerificationType type, TRAPS) {
duke@435:     assert(!type.is_check(), "Must be a real type");
duke@435:     if (_stack_size >= _max_stack) {
duke@435:       verifier()->verify_error(_offset, "Operand stack overflow");
duke@435:       return;
duke@435:     }
duke@435:     _stack[_stack_size++] = type;
duke@435:   }
duke@435: 
duke@435:   inline void push_stack_2(
duke@435:       VerificationType type1, VerificationType type2, TRAPS) {
duke@435:     assert(type1.is_long() || type1.is_double(), "must be long/double");
duke@435:     assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
duke@435:     if (_stack_size >= _max_stack - 1) {
duke@435:       verifier()->verify_error(_offset, "Operand stack overflow");
duke@435:       return;
duke@435:     }
duke@435:     _stack[_stack_size++] = type1;
duke@435:     _stack[_stack_size++] = type2;
duke@435:   }
duke@435: 
duke@435:   // Pop and return the top type on stack without verifying.
duke@435:   inline VerificationType pop_stack(TRAPS) {
duke@435:     if (_stack_size <= 0) {
duke@435:       verifier()->verify_error(_offset, "Operand stack underflow");
duke@435:       return VerificationType::bogus_type();
duke@435:     }
duke@435:     // Put bogus type to indicate it's no longer valid.
duke@435:     // Added to make it consistent with the other pop_stack method.
duke@435:     VerificationType top = _stack[--_stack_size];
duke@435:     NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
duke@435:     return top;
duke@435:   }
duke@435: 
duke@435:   // Pop and return the top type on stack type array after verifying it
duke@435:   // is assignable to type.
duke@435:   inline VerificationType pop_stack(VerificationType type, TRAPS) {
duke@435:     if (_stack_size != 0) {
duke@435:       VerificationType top = _stack[_stack_size - 1];
duke@435:       bool subtype = type.is_assignable_from(
duke@435:         top, verifier()->current_class(),
duke@435:         CHECK_(VerificationType::bogus_type()));
duke@435:       if (subtype) {
duke@435:         _stack_size --;
duke@435:         NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
duke@435:         return top;
duke@435:       }
duke@435:     }
duke@435:     return pop_stack_ex(type, THREAD);
duke@435:   }
duke@435: 
duke@435:   inline void pop_stack_2(
duke@435:       VerificationType type1, VerificationType type2, TRAPS) {
duke@435:     assert(type1.is_long2() || type1.is_double2(), "must be long/double");
duke@435:     assert(type2.is_long() || type2.is_double(), "must be long/double_2");
duke@435:     if (_stack_size >= 2) {
duke@435:       VerificationType top1 = _stack[_stack_size - 1];
duke@435:       bool subtype1 = type1.is_assignable_from(
duke@435:         top1, verifier()->current_class(), CHECK);
duke@435:       VerificationType top2 = _stack[_stack_size - 2];
duke@435:       bool subtype2 = type2.is_assignable_from(
duke@435:         top2, verifier()->current_class(), CHECK);
duke@435:       if (subtype1 && subtype2) {
duke@435:         _stack_size -= 2;
duke@435:         NOT_PRODUCT( _stack[_stack_size] = VerificationType::bogus_type(); )
duke@435:         NOT_PRODUCT( _stack[_stack_size+1] = VerificationType::bogus_type(); )
duke@435:         return;
duke@435:       }
duke@435:     }
duke@435:     pop_stack_ex(type1, THREAD);
duke@435:     pop_stack_ex(type2, THREAD);
duke@435:   }
duke@435: 
duke@435:   // Uncommon case that throws exceptions.
duke@435:   VerificationType pop_stack_ex(VerificationType type, TRAPS);
duke@435: 
duke@435:   // Return the type at index in local variable array after verifying
duke@435:   // it is assignable to type.
duke@435:   VerificationType get_local(int32_t index, VerificationType type, TRAPS);
duke@435:   // For long/double.
duke@435:   void get_local_2(
duke@435:     int32_t index, VerificationType type1, VerificationType type2, TRAPS);
duke@435: 
duke@435:   // Set element at index in local variable array to type.
duke@435:   void set_local(int32_t index, VerificationType type, TRAPS);
duke@435:   // For long/double.
duke@435:   void set_local_2(
duke@435:     int32_t index, VerificationType type1, VerificationType type2, TRAPS);
duke@435: 
duke@435:   // Private auxiliary method used only in is_assignable_to(StackMapFrame).
duke@435:   // Returns true if src is assignable to target.
duke@435:   bool is_assignable_to(
duke@435:     VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
duke@435: 
duke@435:   // Debugging
duke@435:   void print() const PRODUCT_RETURN;
duke@435: };