src/share/vm/interpreter/bytecodeTracer.cpp - platform/external/jetbrains/jdk8u_hotspot - Git at Google

 /*
  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #include "precompiled.hpp"
 #include "interpreter/bytecodeHistogram.hpp"
 #include "interpreter/bytecodeTracer.hpp"
 #include "interpreter/bytecodes.hpp"
 #include "interpreter/interpreter.hpp"
 #include "interpreter/interpreterRuntime.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/methodData.hpp"
 #include "oops/method.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/timer.hpp"


 #ifndef PRODUCT

 // Standard closure for BytecodeTracer: prints the current bytecode
 // and its attributes using bytecode-specific information.

 class BytecodePrinter: public BytecodeClosure {
  private:
   // %%% This field is not GC-ed, and so can contain garbage
   // between critical sections.  Use only pointer-comparison
   // operations on the pointer, except within a critical section.
   // (Also, ensure that occasional false positives are benign.)
   Method* _current_method;
   bool      _is_wide;
   Bytecodes::Code _code;
   address   _next_pc;                // current decoding position

   void      align()                  { _next_pc = (address)round_to((intptr_t)_next_pc, sizeof(jint)); }
   int       get_byte()               { return *(jbyte*) _next_pc++; }  // signed
   short     get_short()              { short i=Bytes::get_Java_u2(_next_pc); _next_pc+=2; return i; }
   int       get_int()                { int i=Bytes::get_Java_u4(_next_pc); _next_pc+=4; return i; }

   int       get_index_u1()           { return *(address)_next_pc++; }
   int       get_index_u2()           { int i=Bytes::get_Java_u2(_next_pc); _next_pc+=2; return i; }
   int       get_index_u1_cpcache()   { return get_index_u1() + ConstantPool::CPCACHE_INDEX_TAG; }
   int       get_index_u2_cpcache()   { int i=Bytes::get_native_u2(_next_pc); _next_pc+=2; return i + ConstantPool::CPCACHE_INDEX_TAG; }
   int       get_index_u4()           { int i=Bytes::get_native_u4(_next_pc); _next_pc+=4; return i; }
   int       get_index_special()      { return (is_wide()) ? get_index_u2() : get_index_u1(); }
   Method* method()                 { return _current_method; }
   bool      is_wide()                { return _is_wide; }
   Bytecodes::Code raw_code()         { return Bytecodes::Code(_code); }


   bool      check_index(int i, int& cp_index, outputStream* st = tty);
   bool      check_cp_cache_index(int i, int& cp_index, outputStream* st = tty);
   bool      check_obj_index(int i, int& cp_index, outputStream* st = tty);
   bool      check_invokedynamic_index(int i, int& cp_index, outputStream* st = tty);
   void      print_constant(int i, outputStream* st = tty);
   void      print_field_or_method(int i, outputStream* st = tty);
   void      print_field_or_method(int orig_i, int i, outputStream* st = tty);
   void      print_attributes(int bci, outputStream* st = tty);
   void      bytecode_epilog(int bci, outputStream* st = tty);

  public:
   BytecodePrinter() {
     _is_wide = false;
     _code = Bytecodes::_illegal;
   }

   // This method is called while executing the raw bytecodes, so none of
   // the adjustments that BytecodeStream performs applies.
   void trace(methodHandle method, address bcp, uintptr_t tos, uintptr_t tos2, outputStream* st) {
     ResourceMark rm;
     if (_current_method != method()) {
       // Note 1: This code will not work as expected with true MT/MP.
       //         Need an explicit lock or a different solution.
       // It is possible for this block to be skipped, if a garbage
       // _current_method pointer happens to have the same bits as
       // the incoming method.  We could lose a line of trace output.
       // This is acceptable in a debug-only feature.
       st->cr();
       st->print("[%ld] ", (long) Thread::current()->osthread()->thread_id());
       method->print_name(st);
       st->cr();
       _current_method = method();
     }
     Bytecodes::Code code;
     if (is_wide()) {
       // bcp wasn't advanced if previous bytecode was _wide.
       code = Bytecodes::code_at(method(), bcp+1);
     } else {
       code = Bytecodes::code_at(method(), bcp);
     }
     _code = code;
      int bci = bcp - method->code_base();
     st->print("[%ld] ", (long) Thread::current()->osthread()->thread_id());
     if (Verbose) {
       st->print("%8d  %4d  " INTPTR_FORMAT " " INTPTR_FORMAT " %s",
            BytecodeCounter::counter_value(), bci, tos, tos2, Bytecodes::name(code));
     } else {
       st->print("%8d  %4d  %s",
            BytecodeCounter::counter_value(), bci, Bytecodes::name(code));
     }
     _next_pc = is_wide() ? bcp+2 : bcp+1;
     print_attributes(bci);
     // Set is_wide for the next one, since the caller of this doesn't skip
     // the next bytecode.
     _is_wide = (code == Bytecodes::_wide);
     _code = Bytecodes::_illegal;
   }

   // Used for Method*::print_codes().  The input bcp comes from
   // BytecodeStream, which will skip wide bytecodes.
   void trace(methodHandle method, address bcp, outputStream* st) {
     _current_method = method();
     ResourceMark rm;
     Bytecodes::Code code = Bytecodes::code_at(method(), bcp);
     // Set is_wide
     _is_wide = (code == Bytecodes::_wide);
     if (is_wide()) {
       code = Bytecodes::code_at(method(), bcp+1);
     }
     _code = code;
     int bci = bcp - method->code_base();
     // Print bytecode index and name
     if (is_wide()) {
       st->print("%d %s_w", bci, Bytecodes::name(code));
     } else {
       st->print("%d %s", bci, Bytecodes::name(code));
     }
     _next_pc = is_wide() ? bcp+2 : bcp+1;
     print_attributes(bci, st);
     bytecode_epilog(bci, st);
   }
 };


 // Implementation of BytecodeTracer

 // %%% This set_closure thing seems overly general, given that
 // nobody uses it.  Also, if BytecodePrinter weren't hidden
 // then Method* could use instances of it directly and it
 // would be easier to remove races on _current_method and bcp.
 // Since this is not product functionality, we can defer cleanup.

 BytecodeClosure* BytecodeTracer::_closure = NULL;

 static BytecodePrinter std_closure;
 BytecodeClosure* BytecodeTracer::std_closure() {
   return &::std_closure;
 }


 void BytecodeTracer::trace(methodHandle method, address bcp, uintptr_t tos, uintptr_t tos2, outputStream* st) {
   if (TraceBytecodes && BytecodeCounter::counter_value() >= TraceBytecodesAt) {
     ttyLocker ttyl;  // 5065316: keep the following output coherent
     // The ttyLocker also prevents races between two threads
     // trying to use the single instance of BytecodePrinter.
     // Using the ttyLocker prevents the system from coming to
     // a safepoint within this code, which is sensitive to Method*
     // movement.
     //
     // There used to be a leaf mutex here, but the ttyLocker will
     // work just as well, as long as the printing operations never block.
     //
     // We put the locker on the static trace method, not the
     // virtual one, because the clients of this module go through
     // the static method.
     _closure->trace(method, bcp, tos, tos2, st);
   }
 }

 void BytecodeTracer::trace(methodHandle method, address bcp, outputStream* st) {
   ttyLocker ttyl;  // 5065316: keep the following output coherent
   _closure->trace(method, bcp, st);
 }

 void print_symbol(Symbol* sym, outputStream* st) {
   char buf[40];
   int len = sym->utf8_length();
   if (len >= (int)sizeof(buf)) {
     st->print_cr(" %s...[%d]", sym->as_C_string(buf, sizeof(buf)), len);
   } else {
     st->print(" ");
     sym->print_on(st); st->cr();
   }
 }

 void print_oop(oop value, outputStream* st) {
   if (value == NULL) {
     st->print_cr(" NULL");
   } else if (java_lang_String::is_instance(value)) {
     char buf[40];
     int len = java_lang_String::utf8_length(value);
     java_lang_String::as_utf8_string(value, buf, sizeof(buf));
     if (len >= (int)sizeof(buf)) {
       st->print_cr(" %s...[%d]", buf, len);
     } else {
       st->print_cr(" %s", buf);
     }
   } else {
     st->print_cr(" " PTR_FORMAT, p2i((void *)value));
   }
 }

 bool BytecodePrinter::check_index(int i, int& cp_index, outputStream* st) {
   ConstantPool* constants = method()->constants();
   int ilimit = constants->length();
   Bytecodes::Code code = raw_code();

   ConstantPoolCache* cache = NULL;
   if (Bytecodes::uses_cp_cache(code)) {
     bool okay = true;
     switch (code) {
     case Bytecodes::_fast_aldc:
     case Bytecodes::_fast_aldc_w:
       okay = check_obj_index(i, cp_index, st);
       break;
     case Bytecodes::_invokedynamic:
       okay = check_invokedynamic_index(i, cp_index, st);
       break;
     default:
       okay = check_cp_cache_index(i, cp_index, st);
       break;
     }
     if (!okay) return false;
   }


   // check cp index
   if (cp_index >= 0 && cp_index < ilimit) {
     if (WizardMode)  st->print(" cp[%d]", cp_index);
     return true;
   }

   st->print_cr(" CP[%d] not in CP", cp_index);
   return false;
 }

 bool BytecodePrinter::check_cp_cache_index(int i, int& cp_index, outputStream* st) {
   ConstantPool* constants = method()->constants();
   int ilimit = constants->length(), climit = 0;
   Bytecodes::Code code = raw_code();

   ConstantPoolCache* cache = constants->cache();
   // If rewriter hasn't run, the index is the cp_index
   if (cache == NULL) {
     cp_index = i;
     return true;
   }
   //climit = cache->length();  // %%% private!
   size_t size = cache->size() * HeapWordSize;
   size -= sizeof(ConstantPoolCache);
   size /= sizeof(ConstantPoolCacheEntry);
   climit = (int) size;

 #ifdef ASSERT
   {
     const int CPCACHE_INDEX_TAG = ConstantPool::CPCACHE_INDEX_TAG;
     if (i >= CPCACHE_INDEX_TAG && i < climit + CPCACHE_INDEX_TAG) {
       i -= CPCACHE_INDEX_TAG;
     } else {
       st->print_cr(" CP[%d] missing bias?", i);
       return false;
     }
   }
 #endif //ASSERT
   if (i >= 0 && i < climit) {
     cp_index = cache->entry_at(i)->constant_pool_index();
   } else {
     st->print_cr("%d not in CP[*]?", i);
       return false;
     }
   return true;
   }


 bool BytecodePrinter::check_obj_index(int i, int& cp_index, outputStream* st) {
   ConstantPool* constants = method()->constants();
   i -= ConstantPool::CPCACHE_INDEX_TAG;

   if (i >= 0 && i < constants->resolved_references()->length()) {
      cp_index = constants->object_to_cp_index(i);
      return true;
   } else {
     st->print_cr("%d not in OBJ[*]?", i);
   return false;
 }
 }


 bool BytecodePrinter::check_invokedynamic_index(int i, int& cp_index, outputStream* st) {
   ConstantPool* constants = method()->constants();
   assert(ConstantPool::is_invokedynamic_index(i), "not secondary index?");
   i = ConstantPool::decode_invokedynamic_index(i) + ConstantPool::CPCACHE_INDEX_TAG;

   return check_cp_cache_index(i, cp_index, st);
 }

 void BytecodePrinter::print_constant(int i, outputStream* st) {
   int orig_i = i;
   if (!check_index(orig_i, i, st))  return;

   ConstantPool* constants = method()->constants();
   constantTag tag = constants->tag_at(i);

   if (tag.is_int()) {
     st->print_cr(" " INT32_FORMAT, constants->int_at(i));
   } else if (tag.is_long()) {
     st->print_cr(" " INT64_FORMAT, (int64_t)(constants->long_at(i)));
   } else if (tag.is_float()) {
     st->print_cr(" %f", constants->float_at(i));
   } else if (tag.is_double()) {
     st->print_cr(" %f", constants->double_at(i));
   } else if (tag.is_string()) {
     const char* string = constants->string_at_noresolve(i);
     st->print_cr(" %s", string);
   } else if (tag.is_klass()) {
     st->print_cr(" %s", constants->resolved_klass_at(i)->external_name());
   } else if (tag.is_unresolved_klass()) {
     st->print_cr(" <unresolved klass at %d>", i);
   } else if (tag.is_method_type()) {
     int i2 = constants->method_type_index_at(i);
     st->print(" <MethodType> %d", i2);
     print_symbol(constants->symbol_at(i2), st);
   } else if (tag.is_method_handle()) {
     int kind = constants->method_handle_ref_kind_at(i);
     int i2 = constants->method_handle_index_at(i);
     st->print(" <MethodHandle of kind %d index at %d>", kind, i2);
     print_field_or_method(-i, i2, st);
   } else {
     st->print_cr(" bad tag=%d at %d", tag.value(), i);
   }
 }

 void BytecodePrinter::print_field_or_method(int i, outputStream* st) {
   int orig_i = i;
   if (!check_index(orig_i, i, st))  return;
   print_field_or_method(orig_i, i, st);
 }

 void BytecodePrinter::print_field_or_method(int orig_i, int i, outputStream* st) {
   ConstantPool* constants = method()->constants();
   constantTag tag = constants->tag_at(i);

   bool has_klass = true;

   switch (tag.value()) {
   case JVM_CONSTANT_InterfaceMethodref:
   case JVM_CONSTANT_Methodref:
   case JVM_CONSTANT_Fieldref:
     break;
   case JVM_CONSTANT_NameAndType:
   case JVM_CONSTANT_InvokeDynamic:
     has_klass = false;
     break;
   default:
     st->print_cr(" bad tag=%d at %d", tag.value(), i);
     return;
   }

   Symbol* name = constants->uncached_name_ref_at(i);
   Symbol* signature = constants->uncached_signature_ref_at(i);
   const char* sep = (tag.is_field() ? "/" : "");
   if (has_klass) {
     Symbol* klass = constants->klass_name_at(constants->uncached_klass_ref_index_at(i));
     st->print_cr(" %d <%s.%s%s%s> ", i, klass->as_C_string(), name->as_C_string(), sep, signature->as_C_string());
   } else {
     if (tag.is_invoke_dynamic()) {
       int bsm = constants->invoke_dynamic_bootstrap_method_ref_index_at(i);
       st->print(" bsm=%d", bsm);
     }
     st->print_cr(" %d <%s%s%s>", i, name->as_C_string(), sep, signature->as_C_string());
   }
 }


 PRAGMA_FORMAT_NONLITERAL_IGNORED_EXTERNAL
 void BytecodePrinter::print_attributes(int bci, outputStream* st) {
   // Show attributes of pre-rewritten codes
   Bytecodes::Code code = Bytecodes::java_code(raw_code());
   // If the code doesn't have any fields there's nothing to print.
   // note this is ==1 because the tableswitch and lookupswitch are
   // zero size (for some reason) and we want to print stuff out for them.
   if (Bytecodes::length_for(code) == 1) {
     st->cr();
     return;
   }

   switch(code) {
     // Java specific bytecodes only matter.
     case Bytecodes::_bipush:
       st->print_cr(" " INT32_FORMAT, get_byte());
       break;
     case Bytecodes::_sipush:
       st->print_cr(" " INT32_FORMAT, get_short());
       break;
     case Bytecodes::_ldc:
       if (Bytecodes::uses_cp_cache(raw_code())) {
         print_constant(get_index_u1_cpcache(), st);
       } else {
         print_constant(get_index_u1(), st);
       }
       break;

     case Bytecodes::_ldc_w:
     case Bytecodes::_ldc2_w:
       if (Bytecodes::uses_cp_cache(raw_code())) {
         print_constant(get_index_u2_cpcache(), st);
       } else {
         print_constant(get_index_u2(), st);
       }
       break;

     case Bytecodes::_iload:
     case Bytecodes::_lload:
     case Bytecodes::_fload:
     case Bytecodes::_dload:
     case Bytecodes::_aload:
     case Bytecodes::_istore:
     case Bytecodes::_lstore:
     case Bytecodes::_fstore:
     case Bytecodes::_dstore:
     case Bytecodes::_astore:
       st->print_cr(" #%d", get_index_special());
       break;

     case Bytecodes::_iinc:
       { int index = get_index_special();
         jint offset = is_wide() ? get_short(): get_byte();
         st->print_cr(" #%d " INT32_FORMAT, index, offset);
       }
       break;

     case Bytecodes::_newarray: {
         BasicType atype = (BasicType)get_index_u1();
         const char* str = type2name(atype);
         if (str == NULL || atype == T_OBJECT || atype == T_ARRAY) {
           assert(false, "Unidentified basic type");
         }
         st->print_cr(" %s", str);
       }
       break;
     case Bytecodes::_anewarray: {
         int klass_index = get_index_u2();
         ConstantPool* constants = method()->constants();
         Symbol* name = constants->klass_name_at(klass_index);
         st->print_cr(" %s ", name->as_C_string());
       }
       break;
     case Bytecodes::_multianewarray: {
         int klass_index = get_index_u2();
         int nof_dims = get_index_u1();
         ConstantPool* constants = method()->constants();
         Symbol* name = constants->klass_name_at(klass_index);
         st->print_cr(" %s %d", name->as_C_string(), nof_dims);
       }
       break;

     case Bytecodes::_ifeq:
     case Bytecodes::_ifnull:
     case Bytecodes::_iflt:
     case Bytecodes::_ifle:
     case Bytecodes::_ifne:
     case Bytecodes::_ifnonnull:
     case Bytecodes::_ifgt:
     case Bytecodes::_ifge:
     case Bytecodes::_if_icmpeq:
     case Bytecodes::_if_icmpne:
     case Bytecodes::_if_icmplt:
     case Bytecodes::_if_icmpgt:
     case Bytecodes::_if_icmple:
     case Bytecodes::_if_icmpge:
     case Bytecodes::_if_acmpeq:
     case Bytecodes::_if_acmpne:
     case Bytecodes::_goto:
     case Bytecodes::_jsr:
       st->print_cr(" %d", bci + get_short());
       break;

     case Bytecodes::_goto_w:
     case Bytecodes::_jsr_w:
       st->print_cr(" %d", bci + get_int());
       break;

     case Bytecodes::_ret: st->print_cr(" %d", get_index_special()); break;

     case Bytecodes::_tableswitch:
       { align();
         int  default_dest = bci + get_int();
         int  lo           = get_int();
         int  hi           = get_int();
         int  len          = hi - lo + 1;
         jint* dest        = NEW_RESOURCE_ARRAY(jint, len);
         for (int i = 0; i < len; i++) {
           dest[i] = bci + get_int();
         }
         st->print(" %d " INT32_FORMAT " " INT32_FORMAT " ",
                       default_dest, lo, hi);
         int first = true;
         for (int ll = lo; ll <= hi; ll++, first = false)  {
           int idx = ll - lo;
           const char *format = first ? " %d:" INT32_FORMAT " (delta: %d)" :
                                        ", %d:" INT32_FORMAT " (delta: %d)";
 PRAGMA_DIAG_PUSH
 PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
           st->print(format, ll, dest[idx], dest[idx]-bci);
 PRAGMA_DIAG_POP
         }
         st->cr();
       }
       break;
     case Bytecodes::_lookupswitch:
       { align();
         int  default_dest = bci + get_int();
         int  len          = get_int();
         jint* key         = NEW_RESOURCE_ARRAY(jint, len);
         jint* dest        = NEW_RESOURCE_ARRAY(jint, len);
         for (int i = 0; i < len; i++) {
           key [i] = get_int();
           dest[i] = bci + get_int();
         };
         st->print(" %d %d ", default_dest, len);
         bool first = true;
         for (int ll = 0; ll < len; ll++, first = false)  {
           const char *format = first ? " " INT32_FORMAT ":" INT32_FORMAT :
                                        ", " INT32_FORMAT ":" INT32_FORMAT ;
 PRAGMA_DIAG_PUSH
 PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
           st->print(format, key[ll], dest[ll]);
 PRAGMA_DIAG_POP
         }
         st->cr();
       }
       break;

     case Bytecodes::_putstatic:
     case Bytecodes::_getstatic:
     case Bytecodes::_putfield:
     case Bytecodes::_getfield:
       print_field_or_method(get_index_u2_cpcache(), st);
       break;

     case Bytecodes::_invokevirtual:
     case Bytecodes::_invokespecial:
     case Bytecodes::_invokestatic:
       print_field_or_method(get_index_u2_cpcache(), st);
       break;

     case Bytecodes::_invokeinterface:
       { int i = get_index_u2_cpcache();
         int n = get_index_u1();
         get_byte();            // ignore zero byte
         print_field_or_method(i, st);
       }
       break;

     case Bytecodes::_invokedynamic:
       print_field_or_method(get_index_u4(), st);
       break;

     case Bytecodes::_new:
     case Bytecodes::_checkcast:
     case Bytecodes::_instanceof:
       { int i = get_index_u2();
         ConstantPool* constants = method()->constants();
         Symbol* name = constants->klass_name_at(i);
         st->print_cr(" %d <%s>", i, name->as_C_string());
       }
       break;

     case Bytecodes::_wide:
       // length is zero not one, but printed with no more info.
       break;

     default:
       ShouldNotReachHere();
       break;
   }
 }


 void BytecodePrinter::bytecode_epilog(int bci, outputStream* st) {
   MethodData* mdo = method()->method_data();
   if (mdo != NULL) {
     ProfileData* data = mdo->bci_to_data(bci);
     if (data != NULL) {
       st->print("  %d", mdo->dp_to_di(data->dp()));
       st->fill_to(6);
       data->print_data_on(st, mdo);
     }
   }
 }
 #endif // PRODUCT
	/*
	* Copyright (c) 1997, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#include "precompiled.hpp"
	#include "interpreter/bytecodeHistogram.hpp"
	#include "interpreter/bytecodeTracer.hpp"
	#include "interpreter/bytecodes.hpp"
	#include "interpreter/interpreter.hpp"
	#include "interpreter/interpreterRuntime.hpp"
	#include "memory/resourceArea.hpp"
	#include "oops/methodData.hpp"
	#include "oops/method.hpp"
	#include "runtime/mutexLocker.hpp"
	#include "runtime/timer.hpp"


	#ifndef PRODUCT

	// Standard closure for BytecodeTracer: prints the current bytecode
	// and its attributes using bytecode-specific information.

	class BytecodePrinter: public BytecodeClosure {
	private:
	// %%% This field is not GC-ed, and so can contain garbage
	// between critical sections. Use only pointer-comparison
	// operations on the pointer, except within a critical section.
	// (Also, ensure that occasional false positives are benign.)
	Method* _current_method;
	bool _is_wide;
	Bytecodes::Code _code;
	address _next_pc; // current decoding position

	void align() { _next_pc = (address)round_to((intptr_t)_next_pc, sizeof(jint)); }
	int get_byte() { return (jbyte) _next_pc++; } // signed
	short get_short() { short i=Bytes::get_Java_u2(_next_pc); _next_pc+=2; return i; }
	int get_int() { int i=Bytes::get_Java_u4(_next_pc); _next_pc+=4; return i; }

	int get_index_u1() { return *(address)_next_pc++; }
	int get_index_u2() { int i=Bytes::get_Java_u2(_next_pc); _next_pc+=2; return i; }
	int get_index_u1_cpcache() { return get_index_u1() + ConstantPool::CPCACHE_INDEX_TAG; }
	int get_index_u2_cpcache() { int i=Bytes::get_native_u2(_next_pc); _next_pc+=2; return i + ConstantPool::CPCACHE_INDEX_TAG; }
	int get_index_u4() { int i=Bytes::get_native_u4(_next_pc); _next_pc+=4; return i; }
	int get_index_special() { return (is_wide()) ? get_index_u2() : get_index_u1(); }
	Method* method() { return _current_method; }
	bool is_wide() { return _is_wide; }
	Bytecodes::Code raw_code() { return Bytecodes::Code(_code); }


	bool check_index(int i, int& cp_index, outputStream* st = tty);
	bool check_cp_cache_index(int i, int& cp_index, outputStream* st = tty);
	bool check_obj_index(int i, int& cp_index, outputStream* st = tty);
	bool check_invokedynamic_index(int i, int& cp_index, outputStream* st = tty);
	void print_constant(int i, outputStream* st = tty);
	void print_field_or_method(int i, outputStream* st = tty);
	void print_field_or_method(int orig_i, int i, outputStream* st = tty);
	void print_attributes(int bci, outputStream* st = tty);
	void bytecode_epilog(int bci, outputStream* st = tty);

	public:
	BytecodePrinter() {
	_is_wide = false;
	_code = Bytecodes::_illegal;
	}

	// This method is called while executing the raw bytecodes, so none of
	// the adjustments that BytecodeStream performs applies.
	void trace(methodHandle method, address bcp, uintptr_t tos, uintptr_t tos2, outputStream* st) {
	ResourceMark rm;
	if (_current_method != method()) {
	// Note 1: This code will not work as expected with true MT/MP.
	// Need an explicit lock or a different solution.
	// It is possible for this block to be skipped, if a garbage
	// _current_method pointer happens to have the same bits as
	// the incoming method. We could lose a line of trace output.
	// This is acceptable in a debug-only feature.
	st->cr();
	st->print("[%ld] ", (long) Thread::current()->osthread()->thread_id());
	method->print_name(st);
	st->cr();
	_current_method = method();
	}
	Bytecodes::Code code;
	if (is_wide()) {
	// bcp wasn't advanced if previous bytecode was _wide.
	code = Bytecodes::code_at(method(), bcp+1);
	} else {
	code = Bytecodes::code_at(method(), bcp);
	}
	_code = code;
	int bci = bcp - method->code_base();
	st->print("[%ld] ", (long) Thread::current()->osthread()->thread_id());
	if (Verbose) {
	st->print("%8d %4d " INTPTR_FORMAT " " INTPTR_FORMAT " %s",
	BytecodeCounter::counter_value(), bci, tos, tos2, Bytecodes::name(code));
	} else {
	st->print("%8d %4d %s",
	BytecodeCounter::counter_value(), bci, Bytecodes::name(code));
	}
	_next_pc = is_wide() ? bcp+2 : bcp+1;
	print_attributes(bci);
	// Set is_wide for the next one, since the caller of this doesn't skip
	// the next bytecode.
	_is_wide = (code == Bytecodes::_wide);
	_code = Bytecodes::_illegal;
	}

	// Used for Method*::print_codes(). The input bcp comes from
	// BytecodeStream, which will skip wide bytecodes.
	void trace(methodHandle method, address bcp, outputStream* st) {
	_current_method = method();
	ResourceMark rm;
	Bytecodes::Code code = Bytecodes::code_at(method(), bcp);
	// Set is_wide
	_is_wide = (code == Bytecodes::_wide);
	if (is_wide()) {
	code = Bytecodes::code_at(method(), bcp+1);
	}
	_code = code;
	int bci = bcp - method->code_base();
	// Print bytecode index and name
	if (is_wide()) {
	st->print("%d %s_w", bci, Bytecodes::name(code));
	} else {
	st->print("%d %s", bci, Bytecodes::name(code));
	}
	_next_pc = is_wide() ? bcp+2 : bcp+1;
	print_attributes(bci, st);
	bytecode_epilog(bci, st);
	}
	};


	// Implementation of BytecodeTracer

	// %%% This set_closure thing seems overly general, given that
	// nobody uses it. Also, if BytecodePrinter weren't hidden
	// then Method* could use instances of it directly and it
	// would be easier to remove races on _current_method and bcp.
	// Since this is not product functionality, we can defer cleanup.

	BytecodeClosure* BytecodeTracer::_closure = NULL;

	static BytecodePrinter std_closure;
	BytecodeClosure* BytecodeTracer::std_closure() {
	return &::std_closure;
	}


	void BytecodeTracer::trace(methodHandle method, address bcp, uintptr_t tos, uintptr_t tos2, outputStream* st) {
	if (TraceBytecodes && BytecodeCounter::counter_value() >= TraceBytecodesAt) {
	ttyLocker ttyl; // 5065316: keep the following output coherent
	// The ttyLocker also prevents races between two threads
	// trying to use the single instance of BytecodePrinter.
	// Using the ttyLocker prevents the system from coming to
	// a safepoint within this code, which is sensitive to Method*
	// movement.
	//
	// There used to be a leaf mutex here, but the ttyLocker will
	// work just as well, as long as the printing operations never block.
	//
	// We put the locker on the static trace method, not the
	// virtual one, because the clients of this module go through
	// the static method.
	_closure->trace(method, bcp, tos, tos2, st);
	}
	}

	void BytecodeTracer::trace(methodHandle method, address bcp, outputStream* st) {
	ttyLocker ttyl; // 5065316: keep the following output coherent
	_closure->trace(method, bcp, st);
	}

	void print_symbol(Symbol* sym, outputStream* st) {
	char buf[40];
	int len = sym->utf8_length();
	if (len >= (int)sizeof(buf)) {
	st->print_cr(" %s...[%d]", sym->as_C_string(buf, sizeof(buf)), len);
	} else {
	st->print(" ");
	sym->print_on(st); st->cr();
	}
	}

	void print_oop(oop value, outputStream* st) {
	if (value == NULL) {
	st->print_cr(" NULL");
	} else if (java_lang_String::is_instance(value)) {
	char buf[40];
	int len = java_lang_String::utf8_length(value);
	java_lang_String::as_utf8_string(value, buf, sizeof(buf));
	if (len >= (int)sizeof(buf)) {
	st->print_cr(" %s...[%d]", buf, len);
	} else {
	st->print_cr(" %s", buf);
	}
	} else {
	st->print_cr(" " PTR_FORMAT, p2i((void *)value));
	}
	}

	bool BytecodePrinter::check_index(int i, int& cp_index, outputStream* st) {
	ConstantPool* constants = method()->constants();
	int ilimit = constants->length();
	Bytecodes::Code code = raw_code();

	ConstantPoolCache* cache = NULL;
	if (Bytecodes::uses_cp_cache(code)) {
	bool okay = true;
	switch (code) {
	case Bytecodes::_fast_aldc:
	case Bytecodes::_fast_aldc_w:
	okay = check_obj_index(i, cp_index, st);
	break;
	case Bytecodes::_invokedynamic:
	okay = check_invokedynamic_index(i, cp_index, st);
	break;
	default:
	okay = check_cp_cache_index(i, cp_index, st);
	break;
	}
	if (!okay) return false;
	}


	// check cp index
	if (cp_index >= 0 && cp_index < ilimit) {
	if (WizardMode) st->print(" cp[%d]", cp_index);
	return true;
	}

	st->print_cr(" CP[%d] not in CP", cp_index);
	return false;
	}

	bool BytecodePrinter::check_cp_cache_index(int i, int& cp_index, outputStream* st) {
	ConstantPool* constants = method()->constants();
	int ilimit = constants->length(), climit = 0;
	Bytecodes::Code code = raw_code();

	ConstantPoolCache* cache = constants->cache();
	// If rewriter hasn't run, the index is the cp_index
	if (cache == NULL) {
	cp_index = i;
	return true;
	}
	//climit = cache->length(); // %%% private!
	size_t size = cache->size() * HeapWordSize;
	size -= sizeof(ConstantPoolCache);
	size /= sizeof(ConstantPoolCacheEntry);
	climit = (int) size;

	#ifdef ASSERT
	{
	const int CPCACHE_INDEX_TAG = ConstantPool::CPCACHE_INDEX_TAG;
	if (i >= CPCACHE_INDEX_TAG && i < climit + CPCACHE_INDEX_TAG) {
	i -= CPCACHE_INDEX_TAG;
	} else {
	st->print_cr(" CP[%d] missing bias?", i);
	return false;
	}
	}
	#endif //ASSERT
	if (i >= 0 && i < climit) {
	cp_index = cache->entry_at(i)->constant_pool_index();
	} else {
	st->print_cr("%d not in CP[*]?", i);
	return false;
	}
	return true;
	}


	bool BytecodePrinter::check_obj_index(int i, int& cp_index, outputStream* st) {
	ConstantPool* constants = method()->constants();
	i -= ConstantPool::CPCACHE_INDEX_TAG;

	if (i >= 0 && i < constants->resolved_references()->length()) {
	cp_index = constants->object_to_cp_index(i);
	return true;
	} else {
	st->print_cr("%d not in OBJ[*]?", i);
	return false;
	}
	}


	bool BytecodePrinter::check_invokedynamic_index(int i, int& cp_index, outputStream* st) {
	ConstantPool* constants = method()->constants();
	assert(ConstantPool::is_invokedynamic_index(i), "not secondary index?");
	i = ConstantPool::decode_invokedynamic_index(i) + ConstantPool::CPCACHE_INDEX_TAG;

	return check_cp_cache_index(i, cp_index, st);
	}

	void BytecodePrinter::print_constant(int i, outputStream* st) {
	int orig_i = i;
	if (!check_index(orig_i, i, st)) return;

	ConstantPool* constants = method()->constants();
	constantTag tag = constants->tag_at(i);

	if (tag.is_int()) {
	st->print_cr(" " INT32_FORMAT, constants->int_at(i));
	} else if (tag.is_long()) {
	st->print_cr(" " INT64_FORMAT, (int64_t)(constants->long_at(i)));
	} else if (tag.is_float()) {
	st->print_cr(" %f", constants->float_at(i));
	} else if (tag.is_double()) {
	st->print_cr(" %f", constants->double_at(i));
	} else if (tag.is_string()) {
	const char* string = constants->string_at_noresolve(i);
	st->print_cr(" %s", string);
	} else if (tag.is_klass()) {
	st->print_cr(" %s", constants->resolved_klass_at(i)->external_name());
	} else if (tag.is_unresolved_klass()) {
	st->print_cr(" <unresolved klass at %d>", i);
	} else if (tag.is_method_type()) {
	int i2 = constants->method_type_index_at(i);
	st->print(" <MethodType> %d", i2);
	print_symbol(constants->symbol_at(i2), st);
	} else if (tag.is_method_handle()) {
	int kind = constants->method_handle_ref_kind_at(i);
	int i2 = constants->method_handle_index_at(i);
	st->print(" <MethodHandle of kind %d index at %d>", kind, i2);
	print_field_or_method(-i, i2, st);
	} else {
	st->print_cr(" bad tag=%d at %d", tag.value(), i);
	}
	}

	void BytecodePrinter::print_field_or_method(int i, outputStream* st) {
	int orig_i = i;
	if (!check_index(orig_i, i, st)) return;
	print_field_or_method(orig_i, i, st);
	}

	void BytecodePrinter::print_field_or_method(int orig_i, int i, outputStream* st) {
	ConstantPool* constants = method()->constants();
	constantTag tag = constants->tag_at(i);

	bool has_klass = true;

	switch (tag.value()) {
	case JVM_CONSTANT_InterfaceMethodref:
	case JVM_CONSTANT_Methodref:
	case JVM_CONSTANT_Fieldref:
	break;
	case JVM_CONSTANT_NameAndType:
	case JVM_CONSTANT_InvokeDynamic:
	has_klass = false;
	break;
	default:
	st->print_cr(" bad tag=%d at %d", tag.value(), i);
	return;
	}

	Symbol* name = constants->uncached_name_ref_at(i);
	Symbol* signature = constants->uncached_signature_ref_at(i);
	const char* sep = (tag.is_field() ? "/" : "");
	if (has_klass) {
	Symbol* klass = constants->klass_name_at(constants->uncached_klass_ref_index_at(i));
	st->print_cr(" %d <%s.%s%s%s> ", i, klass->as_C_string(), name->as_C_string(), sep, signature->as_C_string());
	} else {
	if (tag.is_invoke_dynamic()) {
	int bsm = constants->invoke_dynamic_bootstrap_method_ref_index_at(i);
	st->print(" bsm=%d", bsm);
	}
	st->print_cr(" %d <%s%s%s>", i, name->as_C_string(), sep, signature->as_C_string());
	}
	}


	PRAGMA_FORMAT_NONLITERAL_IGNORED_EXTERNAL
	void BytecodePrinter::print_attributes(int bci, outputStream* st) {
	// Show attributes of pre-rewritten codes
	Bytecodes::Code code = Bytecodes::java_code(raw_code());
	// If the code doesn't have any fields there's nothing to print.
	// note this is ==1 because the tableswitch and lookupswitch are
	// zero size (for some reason) and we want to print stuff out for them.
	if (Bytecodes::length_for(code) == 1) {
	st->cr();
	return;
	}

	switch(code) {
	// Java specific bytecodes only matter.
	case Bytecodes::_bipush:
	st->print_cr(" " INT32_FORMAT, get_byte());
	break;
	case Bytecodes::_sipush:
	st->print_cr(" " INT32_FORMAT, get_short());
	break;
	case Bytecodes::_ldc:
	if (Bytecodes::uses_cp_cache(raw_code())) {
	print_constant(get_index_u1_cpcache(), st);
	} else {
	print_constant(get_index_u1(), st);
	}
	break;

	case Bytecodes::_ldc_w:
	case Bytecodes::_ldc2_w:
	if (Bytecodes::uses_cp_cache(raw_code())) {
	print_constant(get_index_u2_cpcache(), st);
	} else {
	print_constant(get_index_u2(), st);
	}
	break;

	case Bytecodes::_iload:
	case Bytecodes::_lload:
	case Bytecodes::_fload:
	case Bytecodes::_dload:
	case Bytecodes::_aload:
	case Bytecodes::_istore:
	case Bytecodes::_lstore:
	case Bytecodes::_fstore:
	case Bytecodes::_dstore:
	case Bytecodes::_astore:
	st->print_cr(" #%d", get_index_special());
	break;

	case Bytecodes::_iinc:
	{ int index = get_index_special();
	jint offset = is_wide() ? get_short(): get_byte();
	st->print_cr(" #%d " INT32_FORMAT, index, offset);
	}
	break;

	case Bytecodes::_newarray: {
	BasicType atype = (BasicType)get_index_u1();
	const char* str = type2name(atype);
	if (str == NULL \|\| atype == T_OBJECT \|\| atype == T_ARRAY) {
	assert(false, "Unidentified basic type");
	}
	st->print_cr(" %s", str);
	}
	break;
	case Bytecodes::_anewarray: {
	int klass_index = get_index_u2();
	ConstantPool* constants = method()->constants();
	Symbol* name = constants->klass_name_at(klass_index);
	st->print_cr(" %s ", name->as_C_string());
	}
	break;
	case Bytecodes::_multianewarray: {
	int klass_index = get_index_u2();
	int nof_dims = get_index_u1();
	ConstantPool* constants = method()->constants();
	Symbol* name = constants->klass_name_at(klass_index);
	st->print_cr(" %s %d", name->as_C_string(), nof_dims);
	}
	break;

	case Bytecodes::_ifeq:
	case Bytecodes::_ifnull:
	case Bytecodes::_iflt:
	case Bytecodes::_ifle:
	case Bytecodes::_ifne:
	case Bytecodes::_ifnonnull:
	case Bytecodes::_ifgt:
	case Bytecodes::_ifge:
	case Bytecodes::_if_icmpeq:
	case Bytecodes::_if_icmpne:
	case Bytecodes::_if_icmplt:
	case Bytecodes::_if_icmpgt:
	case Bytecodes::_if_icmple:
	case Bytecodes::_if_icmpge:
	case Bytecodes::_if_acmpeq:
	case Bytecodes::_if_acmpne:
	case Bytecodes::_goto:
	case Bytecodes::_jsr:
	st->print_cr(" %d", bci + get_short());
	break;

	case Bytecodes::_goto_w:
	case Bytecodes::_jsr_w:
	st->print_cr(" %d", bci + get_int());
	break;

	case Bytecodes::_ret: st->print_cr(" %d", get_index_special()); break;

	case Bytecodes::_tableswitch:
	{ align();
	int default_dest = bci + get_int();
	int lo = get_int();
	int hi = get_int();
	int len = hi - lo + 1;
	jint* dest = NEW_RESOURCE_ARRAY(jint, len);
	for (int i = 0; i < len; i++) {
	dest[i] = bci + get_int();
	}
	st->print(" %d " INT32_FORMAT " " INT32_FORMAT " ",
	default_dest, lo, hi);
	int first = true;
	for (int ll = lo; ll <= hi; ll++, first = false) {
	int idx = ll - lo;
	const char *format = first ? " %d:" INT32_FORMAT " (delta: %d)" :
	", %d:" INT32_FORMAT " (delta: %d)";
	PRAGMA_DIAG_PUSH
	PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
	st->print(format, ll, dest[idx], dest[idx]-bci);
	PRAGMA_DIAG_POP
	}
	st->cr();
	}
	break;
	case Bytecodes::_lookupswitch:
	{ align();
	int default_dest = bci + get_int();
	int len = get_int();
	jint* key = NEW_RESOURCE_ARRAY(jint, len);
	jint* dest = NEW_RESOURCE_ARRAY(jint, len);
	for (int i = 0; i < len; i++) {
	key [i] = get_int();
	dest[i] = bci + get_int();
	};
	st->print(" %d %d ", default_dest, len);
	bool first = true;
	for (int ll = 0; ll < len; ll++, first = false) {
	const char *format = first ? " " INT32_FORMAT ":" INT32_FORMAT :
	", " INT32_FORMAT ":" INT32_FORMAT ;
	PRAGMA_DIAG_PUSH
	PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
	st->print(format, key[ll], dest[ll]);
	PRAGMA_DIAG_POP
	}
	st->cr();
	}
	break;

	case Bytecodes::_putstatic:
	case Bytecodes::_getstatic:
	case Bytecodes::_putfield:
	case Bytecodes::_getfield:
	print_field_or_method(get_index_u2_cpcache(), st);
	break;

	case Bytecodes::_invokevirtual:
	case Bytecodes::_invokespecial:
	case Bytecodes::_invokestatic:
	print_field_or_method(get_index_u2_cpcache(), st);
	break;

	case Bytecodes::_invokeinterface:
	{ int i = get_index_u2_cpcache();
	int n = get_index_u1();
	get_byte(); // ignore zero byte
	print_field_or_method(i, st);
	}
	break;

	case Bytecodes::_invokedynamic:
	print_field_or_method(get_index_u4(), st);
	break;

	case Bytecodes::_new:
	case Bytecodes::_checkcast:
	case Bytecodes::_instanceof:
	{ int i = get_index_u2();
	ConstantPool* constants = method()->constants();
	Symbol* name = constants->klass_name_at(i);
	st->print_cr(" %d <%s>", i, name->as_C_string());
	}
	break;

	case Bytecodes::_wide:
	// length is zero not one, but printed with no more info.
	break;

	default:
	ShouldNotReachHere();
	break;
	}
	}


	void BytecodePrinter::bytecode_epilog(int bci, outputStream* st) {
	MethodData* mdo = method()->method_data();
	if (mdo != NULL) {
	ProfileData* data = mdo->bci_to_data(bci);
	if (data != NULL) {
	st->print(" %d", mdo->dp_to_di(data->dp()));
	st->fill_to(6);
	data->print_data_on(st, mdo);
	}
	}
	}
	#endif // PRODUCT