Mercurial > hg > graal-jvmci-8
diff src/share/vm/interpreter/bytecodeStream.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | be93aad57795 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/interpreter/bytecodeStream.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,172 @@ +/* + * 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()); } +};