/* * Copyright 1997-2010 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. // Here is the common base class for both RawBytecodeStream and BytecodeStream: class BaseBytecodeStream: 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 _raw_code; bool _is_wide; bool _is_raw; // false in 'cooked' BytecodeStream // Construction BaseBytecodeStream(methodHandle method) : _method(method) { set_interval(0, _method->code_size()); _is_raw = false; } public: // 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()); } bool is_raw() const { return _is_raw; } // 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 raw_code() const { return _raw_code; } bool is_wide() const { return _is_wide; } int instruction_size() const { return (_next_bci - _bci); } bool is_last_bytecode() const { return _next_bci >= _end_bci; } address bcp() const { return method()->code_base() + _bci; } Bytecode* bytecode() const { return Bytecode_at(bcp()); } // 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() + bytecode()->get_offset_s2(raw_code()); } int dest_w() const { return bci() + bytecode()->get_offset_s4(raw_code()); } // One-byte indices. int get_index_u1() const { assert_raw_index_size(1); return *(jubyte*)(bcp()+1); } protected: void assert_raw_index_size(int size) const NOT_DEBUG_RETURN; void assert_raw_stream(bool want_raw) const NOT_DEBUG_RETURN; }; class RawBytecodeStream: public BaseBytecodeStream { public: // Construction RawBytecodeStream(methodHandle method) : BaseBytecodeStream(method) { _is_raw = true; } public: // 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 = this->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; _raw_code = code; return code; } else { return raw_next_special(code); } } Bytecodes::Code raw_next_special(Bytecodes::Code code); // Unsigned indices, widening, with no swapping of bytes int get_index() const { return (is_wide()) ? get_index_u2_raw(bcp() + 2) : get_index_u1(); } // Get an unsigned 2-byte index, with no swapping of bytes. int get_index_u2() const { assert(!is_wide(), ""); return get_index_u2_raw(bcp() + 1); } private: int get_index_u2_raw(address p) const { assert_raw_index_size(2); assert_raw_stream(true); return Bytes::get_Java_u2(p); } }; // In BytecodeStream, non-java bytecodes will be translated into the // corresponding java bytecodes. class BytecodeStream: public BaseBytecodeStream { Bytecodes::Code _code; public: // Construction BytecodeStream(methodHandle method) : BaseBytecodeStream(method) { } // Iteration Bytecodes::Code next() { Bytecodes::Code raw_code, code; // set reading position _bci = _next_bci; if (is_last_bytecode()) { // indicate end of bytecode stream raw_code = code = Bytecodes::_illegal; } else { // get bytecode address bcp = this->bcp(); raw_code = Bytecodes::code_at(bcp); code = Bytecodes::java_code(raw_code); // 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) { raw_code = (Bytecodes::Code)bcp[1]; code = raw_code; // wide BCs are always Java-normal _is_wide = true; } assert(Bytecodes::is_java_code(code), "sanity check"); } _raw_code = raw_code; _code = code; return _code; } bool is_active_breakpoint() const { return Bytecodes::is_active_breakpoint_at(bcp()); } Bytecodes::Code code() const { return _code; } // Unsigned indices, widening int get_index() const { return is_wide() ? bytecode()->get_index_u2(raw_code(), true) : get_index_u1(); } // Get an unsigned 2-byte index, swapping the bytes if necessary. int get_index_u2() const { assert_raw_stream(false); return bytecode()->get_index_u2(raw_code(), false); } // Get an unsigned 2-byte index in native order. int get_index_u2_cpcache() const { assert_raw_stream(false); return bytecode()->get_index_u2_cpcache(raw_code()); } int get_index_u4() const { assert_raw_stream(false); return bytecode()->get_index_u4(raw_code()); } int has_index_u4() const { return bytecode()->get_index_u4(raw_code()); } };