| /* |
| * Copyright 1997-2005 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. |
| * |
| */ |
| |
| // A BytecodeStream is used for fast iteration over the bytecodes |
| // of a methodOop. |
| // |
| // Usage: |
| // |
| // BytecodeStream s(method); |
| // Bytecodes::Code c; |
| // while ((c = s.next()) >= 0) { |
| // ... |
| // } |
| // |
| // A RawBytecodeStream is a simple version of BytecodeStream. |
| // It is used ONLY when we know the bytecodes haven't been rewritten |
| // yet, such as in the rewriter or the verifier. Currently only the |
| // verifier uses this class. |
| |
| class RawBytecodeStream: StackObj { |
| protected: |
| // stream buffer |
| methodHandle _method; // read from method directly |
| |
| // reading position |
| int _bci; // bci if current bytecode |
| int _next_bci; // bci of next bytecode |
| int _end_bci; // bci after the current iteration interval |
| |
| // last bytecode read |
| Bytecodes::Code _code; |
| bool _is_wide; |
| |
| public: |
| // Construction |
| RawBytecodeStream(methodHandle method) : _method(method) { |
| set_interval(0, _method->code_size()); |
| } |
| |
| // Iteration control |
| void set_interval(int beg_bci, int end_bci) { |
| // iterate over the interval [beg_bci, end_bci) |
| assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci"); |
| assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci"); |
| // setup of iteration pointers |
| _bci = beg_bci; |
| _next_bci = beg_bci; |
| _end_bci = end_bci; |
| } |
| void set_start (int beg_bci) { |
| set_interval(beg_bci, _method->code_size()); |
| } |
| |
| // Iteration |
| // Use raw_next() rather than next() for faster method reference |
| Bytecodes::Code raw_next() { |
| Bytecodes::Code code; |
| // set reading position |
| _bci = _next_bci; |
| assert(!is_last_bytecode(), "caller should check is_last_bytecode()"); |
| |
| address bcp = RawBytecodeStream::bcp(); |
| code = Bytecodes::code_or_bp_at(bcp); |
| |
| // set next bytecode position |
| int l = Bytecodes::length_for(code); |
| if (l > 0 && (_bci + l) <= _end_bci) { |
| assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch |
| && code != Bytecodes::_lookupswitch, "can't be special bytecode"); |
| _is_wide = false; |
| _next_bci += l; |
| _code = code; |
| return code; |
| } else if (code == Bytecodes::_wide && _bci + 1 >= _end_bci) { |
| return Bytecodes::_illegal; |
| } else { |
| return raw_next_special(code); |
| } |
| } |
| Bytecodes::Code raw_next_special(Bytecodes::Code code); |
| |
| // Stream attributes |
| methodHandle method() const { return _method; } |
| |
| int bci() const { return _bci; } |
| int next_bci() const { return _next_bci; } |
| int end_bci() const { return _end_bci; } |
| |
| Bytecodes::Code code() const { return _code; } |
| bool is_wide() const { return _is_wide; } |
| bool is_last_bytecode() const { return _next_bci >= _end_bci; } |
| |
| address bcp() const { return method()->code_base() + _bci; } |
| address next_bcp() { return method()->code_base() + _next_bci; } |
| |
| // State changes |
| void set_next_bci(int bci) { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; } |
| |
| // Bytecode-specific attributes |
| int dest() const { return bci() + (short)Bytes::get_Java_u2(bcp() + 1); } |
| int dest_w() const { return bci() + (int )Bytes::get_Java_u4(bcp() + 1); } |
| |
| // Unsigned indices, widening |
| int get_index() const { return (is_wide()) ? Bytes::get_Java_u2(bcp() + 2) : bcp()[1]; } |
| int get_index_big() const { return (int)Bytes::get_Java_u2(bcp() + 1); } |
| }; |
| |
| // In BytecodeStream, non-java bytecodes will be translated into the |
| // corresponding java bytecodes. |
| |
| class BytecodeStream: public RawBytecodeStream { |
| public: |
| // Construction |
| BytecodeStream(methodHandle method) : RawBytecodeStream(method) { } |
| |
| // Iteration |
| Bytecodes::Code next() { |
| Bytecodes::Code code; |
| // set reading position |
| _bci = _next_bci; |
| if (is_last_bytecode()) { |
| // indicate end of bytecode stream |
| code = Bytecodes::_illegal; |
| } else { |
| // get bytecode |
| address bcp = BytecodeStream::bcp(); |
| code = Bytecodes::java_code_at(bcp); |
| // set next bytecode position |
| // |
| // note that we cannot advance before having the |
| // tty bytecode otherwise the stepping is wrong! |
| // (carefull: length_for(...) must be used first!) |
| int l = Bytecodes::length_for(code); |
| if (l == 0) l = Bytecodes::length_at(bcp); |
| _next_bci += l; |
| assert(_bci < _next_bci, "length must be > 0"); |
| // set attributes |
| _is_wide = false; |
| // check for special (uncommon) cases |
| if (code == Bytecodes::_wide) { |
| code = (Bytecodes::Code)bcp[1]; |
| _is_wide = true; |
| } |
| assert(Bytecodes::is_java_code(code), "sanity check"); |
| } |
| _code = code; |
| return _code; |
| } |
| |
| bool is_active_breakpoint() const { return Bytecodes::is_active_breakpoint_at(bcp()); } |
| }; |
