--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/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()); }
+};