duke@435: /*
duke@435:  * Copyright 1999-2005 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: // ciBytecodeStream
duke@435: //
duke@435: // The class is used to iterate over the bytecodes of a method.
duke@435: // It hides the details of constant pool structure/access by
duke@435: // providing accessors for constant pool items.  It returns only pure
duke@435: // Java bytecodes; VM-internal _fast bytecodes are translated back to
duke@435: // their original form during iteration.
duke@435: class ciBytecodeStream : StackObj {
duke@435: private:
duke@435:  // Handling for the weird bytecodes
duke@435:   Bytecodes::Code wide();       // Handle wide bytecode
duke@435:   Bytecodes::Code table(Bytecodes::Code); // Handle complicated inline table
duke@435: 
duke@435:   static Bytecodes::Code check_java(Bytecodes::Code c) {
duke@435:     assert(Bytecodes::is_java_code(c), "should not return _fast bytecodes");
duke@435:     return c;
duke@435:   }
duke@435: 
duke@435:   ciMethod* _method;           // the method
duke@435:   ciInstanceKlass* _holder;
duke@435:   address _bc_start;            // Start of current bytecode for table
duke@435:   address _was_wide;            // Address past last wide bytecode
duke@435:   jint* _table_base;            // Aligned start of last table or switch
duke@435: 
duke@435:   address _start;                  // Start of bytecodes
duke@435:   address _end;                    // Past end of bytecodes
duke@435:   address _pc;                     // Current PC
duke@435:   Bytecodes::Code _bc;             // Current bytecode
duke@435: 
duke@435:   void reset( address base, unsigned int size ) {
duke@435:     _bc_start =_was_wide = 0;
duke@435:     _start = _pc = base; _end = base + size; }
duke@435: 
duke@435: public:
duke@435:   // End-Of-Bytecodes
duke@435:   static Bytecodes::Code EOBC() {
duke@435:     return Bytecodes::_illegal;
duke@435:   }
duke@435: 
duke@435:   ciBytecodeStream(ciMethod* m) {
duke@435:     reset_to_method(m);
duke@435:   }
duke@435: 
duke@435:   ciBytecodeStream() {
duke@435:     reset_to_method(NULL);
duke@435:   }
duke@435: 
duke@435:   ciMethod* method() const { return _method; }
duke@435: 
duke@435:   void reset_to_method(ciMethod* m) {
duke@435:     _method = m;
duke@435:     if (m == NULL) {
duke@435:       _holder = NULL;
duke@435:       reset(NULL, 0);
duke@435:     } else {
duke@435:       _holder = m->holder();
duke@435:       reset(m->code(), m->code_size());
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   void reset_to_bci( int bci );
duke@435: 
duke@435:   // Force the iterator to report a certain bci.
duke@435:   void force_bci(int bci);
duke@435: 
duke@435:   void set_max_bci( int max ) {
duke@435:     _end = _start + max;
duke@435:   }
duke@435: 
duke@435:   address cur_bcp()             { return _bc_start; }  // Returns bcp to current instruction
duke@435:   int next_bci() const          { return _pc -_start; }
duke@435:   int cur_bci() const           { return _bc_start - _start; }
duke@435: 
duke@435:   Bytecodes::Code cur_bc() const{ return check_java(_bc); }
duke@435:   Bytecodes::Code next_bc()     { return Bytecodes::java_code((Bytecodes::Code)* _pc); }
duke@435: 
duke@435:   // Return current ByteCode and increment PC to next bytecode, skipping all
duke@435:   // intermediate constants.  Returns EOBC at end.
duke@435:   // Expected usage:
duke@435:   //     while( (bc = iter.next()) != EOBC() ) { ... }
duke@435:   Bytecodes::Code next() {
duke@435:     _bc_start = _pc;                        // Capture start of bc
duke@435:     if( _pc >= _end ) return EOBC();        // End-Of-Bytecodes
duke@435: 
duke@435:     // Fetch Java bytecode
duke@435:     // All rewritten bytecodes maintain the size of original bytecode.
duke@435:     _bc = Bytecodes::java_code((Bytecodes::Code)*_pc);
duke@435:     int csize = Bytecodes::length_for(_bc); // Expected size
duke@435: 
duke@435:     if( _bc == Bytecodes::_wide ) {
duke@435:       _bc=wide();                           // Handle wide bytecode
duke@435:     } else if( csize == 0 ) {
duke@435:       _bc=table(_bc);                       // Handle inline tables
duke@435:     } else {
duke@435:       _pc += csize;                         // Bump PC past bytecode
duke@435:     }
duke@435:     return check_java(_bc);
duke@435:   }
duke@435: 
duke@435:   bool is_wide()  { return ( _pc == _was_wide ); }
duke@435: 
duke@435:   // Get a byte index following this bytecode.
duke@435:   // If prefixed with a wide bytecode, get a wide index.
duke@435:   int get_index() const {
duke@435:     return (_pc == _was_wide)   // was widened?
duke@435:       ? Bytes::get_Java_u2(_bc_start+2) // yes, return wide index
duke@435:       : _bc_start[1];           // no, return narrow index
duke@435:   }
duke@435: 
duke@435:   // Set a byte index following this bytecode.
duke@435:   // If prefixed with a wide bytecode, get a wide index.
duke@435:   void put_index(int idx) {
duke@435:       if (_pc == _was_wide)     // was widened?
duke@435:          Bytes::put_Java_u2(_bc_start+2,idx);   // yes, set wide index
duke@435:       else
duke@435:          _bc_start[1]=idx;              // no, set narrow index
duke@435:   }
duke@435: 
duke@435:   // Get 2-byte index (getfield/putstatic/etc)
duke@435:   int get_index_big() const { return Bytes::get_Java_u2(_bc_start+1); }
duke@435: 
duke@435:   // Get dimensions byte (multinewarray)
duke@435:   int get_dimensions() const { return *(unsigned char*)(_pc-1); }
duke@435: 
duke@435:   // Get unsigned index fast
duke@435:   int get_index_fast() const { return Bytes::get_native_u2(_pc-2); }
duke@435: 
duke@435:   // Sign-extended index byte/short, no widening
duke@435:   int get_byte() const { return (int8_t)(_pc[-1]); }
duke@435:   int get_short() const { return (int16_t)Bytes::get_Java_u2(_pc-2); }
duke@435:   int get_long() const  { return (int32_t)Bytes::get_Java_u4(_pc-4); }
duke@435: 
duke@435:   // Get a byte signed constant for "iinc".  Invalid for other bytecodes.
duke@435:   // If prefixed with a wide bytecode, get a wide constant
duke@435:   int get_iinc_con() const {return (_pc==_was_wide) ? get_short() :get_byte();}
duke@435: 
duke@435:   // 2-byte branch offset from current pc
duke@435:   int get_dest( ) const {
duke@435:     assert( Bytecodes::length_at(_bc_start) == sizeof(jshort)+1,  "get_dest called with bad bytecode" );
duke@435:     return _bc_start-_start + (short)Bytes::get_Java_u2(_pc-2);
duke@435:   }
duke@435: 
duke@435:   // 2-byte branch offset from next pc
duke@435:   int next_get_dest( ) const {
duke@435:     address next_bc_start = _pc;
duke@435:     assert( _pc < _end, "" );
duke@435:     Bytecodes::Code next_bc = (Bytecodes::Code)*_pc;
duke@435:     assert( next_bc != Bytecodes::_wide, "");
duke@435:     int next_csize = Bytecodes::length_for(next_bc);
duke@435:     assert( next_csize != 0, "" );
duke@435:     assert( next_bc <= Bytecodes::_jsr_w, "");
duke@435:     address next_pc = _pc + next_csize;
duke@435:     assert( Bytecodes::length_at(next_bc_start) == sizeof(jshort)+1,  "next_get_dest called with bad bytecode" );
duke@435:     return next_bc_start-_start + (short)Bytes::get_Java_u2(next_pc-2);
duke@435:   }
duke@435: 
duke@435:   // 4-byte branch offset from current pc
duke@435:   int get_far_dest( ) const {
duke@435:     assert( Bytecodes::length_at(_bc_start) == sizeof(jint)+1, "dest4 called with bad bytecode" );
duke@435:     return _bc_start-_start + (int)Bytes::get_Java_u4(_pc-4);
duke@435:   }
duke@435: 
duke@435:   // For a lookup or switch table, return target destination
duke@435:   int get_int_table( int index ) const {
duke@435:     return Bytes::get_Java_u4((address)&_table_base[index]); }
duke@435: 
duke@435:   // For tableswitch - get length of offset part
duke@435:   int get_tableswitch_length()  { return get_int_table(2)-get_int_table(1)+1; }
duke@435: 
duke@435:   int get_dest_table( int index ) const {
duke@435:     return cur_bci() + get_int_table(index); }
duke@435: 
duke@435:   // --- Constant pool access ---
duke@435:   int get_constant_index() const;
duke@435:   int get_field_index();
duke@435:   int get_method_index();
duke@435: 
duke@435:   // If this bytecode is a new, newarray, multianewarray, instanceof,
duke@435:   // or checkcast, get the referenced klass.
duke@435:   ciKlass* get_klass(bool& will_link);
duke@435:   int get_klass_index() const;
duke@435: 
duke@435:   // If this bytecode is one of the ldc variants, get the referenced
duke@435:   // constant
duke@435:   ciConstant get_constant();
duke@435:   // True if the ldc variant points to an unresolved string
duke@435:   bool is_unresolved_string() const;
duke@435:   // True if the ldc variant points to an unresolved klass
duke@435:   bool is_unresolved_klass() const;
duke@435: 
duke@435:   // If this bytecode is one of get_field, get_static, put_field,
duke@435:   // or put_static, get the referenced field.
duke@435:   ciField* get_field(bool& will_link);
duke@435: 
duke@435:   ciInstanceKlass* get_declared_field_holder();
duke@435:   int      get_field_holder_index();
duke@435:   int      get_field_signature_index();
duke@435: 
duke@435:   // If this is a method invocation bytecode, get the invoked method.
duke@435:   ciMethod* get_method(bool& will_link);
duke@435:   ciKlass*  get_declared_method_holder();
duke@435:   int       get_method_holder_index();
duke@435:   int       get_method_signature_index();
duke@435: };
duke@435: 
duke@435: 
duke@435: // ciSignatureStream
duke@435: //
duke@435: // The class is used to iterate over the elements of a method signature.
duke@435: class ciSignatureStream : public StackObj {
duke@435: private:
duke@435:   ciSignature* _sig;
duke@435:   int    _pos;
duke@435: public:
duke@435:   ciSignatureStream(ciSignature* signature) {
duke@435:     _sig = signature;
duke@435:     _pos = 0;
duke@435:   }
duke@435: 
duke@435:   bool at_return_type() { return _pos == _sig->count(); }
duke@435: 
duke@435:   bool is_done() { return _pos > _sig->count(); }
duke@435: 
duke@435:   void next() {
duke@435:     if (_pos <= _sig->count()) {
duke@435:       _pos++;
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   ciType* type() {
duke@435:     if (at_return_type()) {
duke@435:       return _sig->return_type();
duke@435:     } else {
duke@435:       return _sig->type_at(_pos);
duke@435:     }
duke@435:   }
duke@435: };
duke@435: 
duke@435: 
duke@435: // ciExceptionHandlerStream
duke@435: //
duke@435: // The class is used to iterate over the exception handlers of
duke@435: // a method.
duke@435: class ciExceptionHandlerStream : public StackObj {
duke@435: private:
duke@435:   // The method whose handlers we are traversing
duke@435:   ciMethod* _method;
duke@435: 
duke@435:   // Our current position in the list of handlers
duke@435:   int        _pos;
duke@435:   int        _end;
duke@435: 
duke@435:   ciInstanceKlass*  _exception_klass;
duke@435:   int        _bci;
duke@435:   bool       _is_exact;
duke@435: 
duke@435: public:
duke@435:   ciExceptionHandlerStream(ciMethod* method) {
duke@435:     _method = method;
duke@435: 
duke@435:     // Force loading of method code and handlers.
duke@435:     _method->code();
duke@435: 
duke@435:     _pos = 0;
duke@435:     _end = _method->_handler_count;
duke@435:     _exception_klass = NULL;
duke@435:     _bci    = -1;
duke@435:     _is_exact = false;
duke@435:   }
duke@435: 
duke@435:   ciExceptionHandlerStream(ciMethod* method, int bci,
duke@435:                            ciInstanceKlass* exception_klass = NULL,
duke@435:                            bool is_exact = false) {
duke@435:     _method = method;
duke@435: 
duke@435:     // Force loading of method code and handlers.
duke@435:     _method->code();
duke@435: 
duke@435:     _pos = -1;
duke@435:     _end = _method->_handler_count + 1; // include the rethrow handler
duke@435:     _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
duke@435:                           ? exception_klass
duke@435:                           : NULL);
duke@435:     _bci = bci;
duke@435:     assert(_bci >= 0, "bci out of range");
duke@435:     _is_exact = is_exact;
duke@435:     next();
duke@435:   }
duke@435: 
duke@435:   // These methods are currently implemented in an odd way.
duke@435:   // Count the number of handlers the iterator has ever produced
duke@435:   // or will ever produce.  Do not include the final rethrow handler.
duke@435:   // That is, a trivial exception handler stream will have a count
duke@435:   // of zero and produce just the rethrow handler.
duke@435:   int count();
duke@435: 
duke@435:   // Count the number of handlers this stream will produce from now on.
duke@435:   // Include the current handler, and the final rethrow handler.
duke@435:   // The remaining count will be zero iff is_done() is true,
duke@435:   int count_remaining();
duke@435: 
duke@435:   bool is_done() {
duke@435:     return (_pos >= _end);
duke@435:   }
duke@435: 
duke@435:   void next() {
duke@435:     _pos++;
duke@435:     if (_bci != -1) {
duke@435:       // We are not iterating over all handlers...
duke@435:       while (!is_done()) {
duke@435:         ciExceptionHandler* handler = _method->_exception_handlers[_pos];
duke@435:         if (handler->is_in_range(_bci)) {
duke@435:           if (handler->is_catch_all()) {
duke@435:             // Found final active catch block.
duke@435:             _end = _pos+1;
duke@435:             return;
duke@435:           } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
duke@435:             // We cannot do any type analysis here.  Must conservatively assume
duke@435:             // catch block is reachable.
duke@435:             return;
duke@435:           } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
duke@435:             // This catch clause will definitely catch the exception.
duke@435:             // Final candidate.
duke@435:             _end = _pos+1;
duke@435:             return;
duke@435:           } else if (!_is_exact &&
duke@435:                      handler->catch_klass()->is_subtype_of(_exception_klass)) {
duke@435:             // This catch block may be reachable.
duke@435:             return;
duke@435:           }
duke@435:         }
duke@435: 
duke@435:         // The catch block was not pertinent.  Go on.
duke@435:         _pos++;
duke@435:       }
duke@435:     } else {
duke@435:       // This is an iteration over all handlers.
duke@435:       return;
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   ciExceptionHandler* handler() {
duke@435:     return _method->_exception_handlers[_pos];
duke@435:   }
duke@435: };