duke@435: /*
duke@435:  * Copyright 1998-2005 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_rewriter.cpp.incl"
duke@435: 
duke@435: 
duke@435: // Computes an index_map (new_index -> original_index) for contant pool entries
duke@435: // that are referred to by the interpreter at runtime via the constant pool cache.
duke@435: void Rewriter::compute_index_maps(constantPoolHandle pool, intArray*& index_map, intStack*& inverse_index_map) {
duke@435:   const int length  = pool->length();
duke@435:   index_map         = new intArray(length, -1);
duke@435:   // Choose an initial value large enough that we don't get frequent
duke@435:   // calls to grow().
duke@435:   inverse_index_map = new intStack(length / 2);
duke@435:   for (int i = 0; i < length; i++) {
duke@435:     switch (pool->tag_at(i).value()) {
duke@435:       case JVM_CONSTANT_Fieldref          : // fall through
duke@435:       case JVM_CONSTANT_Methodref         : // fall through
duke@435:       case JVM_CONSTANT_InterfaceMethodref: {
duke@435:         index_map->at_put(i, inverse_index_map->length());
duke@435:         inverse_index_map->append(i);
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: // Creates a constant pool cache given an inverse_index_map
duke@435: constantPoolCacheHandle Rewriter::new_constant_pool_cache(intArray& inverse_index_map, TRAPS) {
duke@435:   const int length = inverse_index_map.length();
duke@435:   constantPoolCacheOop cache = oopFactory::new_constantPoolCache(length, CHECK_(constantPoolCacheHandle()));
duke@435:   cache->initialize(inverse_index_map);
duke@435:   return constantPoolCacheHandle(THREAD, cache);
duke@435: }
duke@435: 
duke@435: 
duke@435: 
duke@435: // The new finalization semantics says that registration of
duke@435: // finalizable objects must be performed on successful return from the
duke@435: // Object.<init> constructor.  We could implement this trivially if
duke@435: // <init> were never rewritten but since JVMTI allows this to occur, a
duke@435: // more complicated solution is required.  A special return bytecode
duke@435: // is used only by Object.<init> to signal the finalization
duke@435: // registration point.  Additionally local 0 must be preserved so it's
duke@435: // available to pass to the registration function.  For simplicty we
duke@435: // require that local 0 is never overwritten so it's available as an
duke@435: // argument for registration.
duke@435: 
duke@435: void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) {
duke@435:   RawBytecodeStream bcs(method);
duke@435:   while (!bcs.is_last_bytecode()) {
duke@435:     Bytecodes::Code opcode = bcs.raw_next();
duke@435:     switch (opcode) {
duke@435:       case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
duke@435: 
duke@435:       case Bytecodes::_istore:
duke@435:       case Bytecodes::_lstore:
duke@435:       case Bytecodes::_fstore:
duke@435:       case Bytecodes::_dstore:
duke@435:       case Bytecodes::_astore:
duke@435:         if (bcs.get_index() != 0) continue;
duke@435: 
duke@435:         // fall through
duke@435:       case Bytecodes::_istore_0:
duke@435:       case Bytecodes::_lstore_0:
duke@435:       case Bytecodes::_fstore_0:
duke@435:       case Bytecodes::_dstore_0:
duke@435:       case Bytecodes::_astore_0:
duke@435:         THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
duke@435:                   "can't overwrite local 0 in Object.<init>");
duke@435:         break;
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: // Rewrites a method given the index_map information
duke@435: methodHandle Rewriter::rewrite_method(methodHandle method, intArray& index_map, TRAPS) {
duke@435: 
duke@435:   int nof_jsrs = 0;
duke@435:   bool has_monitor_bytecodes = false;
duke@435: 
duke@435:   {
duke@435:     // We cannot tolerate a GC in this block, because we've
duke@435:     // cached the bytecodes in 'code_base'. If the methodOop
duke@435:     // moves, the bytecodes will also move.
duke@435:     No_Safepoint_Verifier nsv;
duke@435:     Bytecodes::Code c;
duke@435: 
duke@435:     // Bytecodes and their length
duke@435:     const address code_base = method->code_base();
duke@435:     const int code_length = method->code_size();
duke@435: 
duke@435:     int bc_length;
duke@435:     for (int bci = 0; bci < code_length; bci += bc_length) {
duke@435:       address bcp = code_base + bci;
duke@435:       c = (Bytecodes::Code)(*bcp);
duke@435: 
duke@435:       // Since we have the code, see if we can get the length
duke@435:       // directly. Some more complicated bytecodes will report
duke@435:       // a length of zero, meaning we need to make another method
duke@435:       // call to calculate the length.
duke@435:       bc_length = Bytecodes::length_for(c);
duke@435:       if (bc_length == 0) {
duke@435:         bc_length = Bytecodes::length_at(bcp);
duke@435: 
duke@435:         // length_at will put us at the bytecode after the one modified
duke@435:         // by 'wide'. We don't currently examine any of the bytecodes
duke@435:         // modified by wide, but in case we do in the future...
duke@435:         if (c == Bytecodes::_wide) {
duke@435:           c = (Bytecodes::Code)bcp[1];
duke@435:         }
duke@435:       }
duke@435: 
duke@435:       assert(bc_length != 0, "impossible bytecode length");
duke@435: 
duke@435:       switch (c) {
duke@435:         case Bytecodes::_lookupswitch   : {
duke@435: #ifndef CC_INTERP
duke@435:           Bytecode_lookupswitch* bc = Bytecode_lookupswitch_at(bcp);
duke@435:           bc->set_code(
duke@435:             bc->number_of_pairs() < BinarySwitchThreshold
duke@435:             ? Bytecodes::_fast_linearswitch
duke@435:             : Bytecodes::_fast_binaryswitch
duke@435:           );
duke@435: #endif
duke@435:           break;
duke@435:         }
duke@435:         case Bytecodes::_getstatic      : // fall through
duke@435:         case Bytecodes::_putstatic      : // fall through
duke@435:         case Bytecodes::_getfield       : // fall through
duke@435:         case Bytecodes::_putfield       : // fall through
duke@435:         case Bytecodes::_invokevirtual  : // fall through
duke@435:         case Bytecodes::_invokespecial  : // fall through
duke@435:         case Bytecodes::_invokestatic   : // fall through
duke@435:         case Bytecodes::_invokeinterface: {
duke@435:           address p = bcp + 1;
duke@435:           Bytes::put_native_u2(p, index_map[Bytes::get_Java_u2(p)]);
duke@435:           break;
duke@435:         }
duke@435:         case Bytecodes::_jsr            : // fall through
duke@435:         case Bytecodes::_jsr_w          : nof_jsrs++;                   break;
duke@435:         case Bytecodes::_monitorenter   : // fall through
duke@435:         case Bytecodes::_monitorexit    : has_monitor_bytecodes = true; break;
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // Update access flags
duke@435:   if (has_monitor_bytecodes) {
duke@435:     method->set_has_monitor_bytecodes();
duke@435:   }
duke@435: 
duke@435:   // The present of a jsr bytecode implies that the method might potentially
duke@435:   // have to be rewritten, so we run the oopMapGenerator on the method
duke@435:   if (nof_jsrs > 0) {
duke@435:     method->set_has_jsrs();
duke@435:     ResolveOopMapConflicts romc(method);
duke@435:     methodHandle original_method = method;
duke@435:     method = romc.do_potential_rewrite(CHECK_(methodHandle()));
duke@435:     if (method() != original_method()) {
duke@435:       // Insert invalid bytecode into original methodOop and set
duke@435:       // interpreter entrypoint, so that a executing this method
duke@435:       // will manifest itself in an easy recognizable form.
duke@435:       address bcp = original_method->bcp_from(0);
duke@435:       *bcp = (u1)Bytecodes::_shouldnotreachhere;
duke@435:       int kind = Interpreter::method_kind(original_method);
duke@435:       original_method->set_interpreter_kind(kind);
duke@435:     }
duke@435: 
duke@435:     // Update monitor matching info.
duke@435:     if (romc.monitor_safe()) {
duke@435:       method->set_guaranteed_monitor_matching();
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // Setup method entrypoints for compiler and interpreter
duke@435:   method->link_method(method, CHECK_(methodHandle()));
duke@435: 
duke@435:   return method;
duke@435: }
duke@435: 
duke@435: 
duke@435: void Rewriter::rewrite(instanceKlassHandle klass, TRAPS) {
duke@435:   // gather starting points
duke@435:   ResourceMark rm(THREAD);
duke@435:   constantPoolHandle pool (THREAD, klass->constants());
duke@435:   objArrayHandle methods  (THREAD, klass->methods());
duke@435:   assert(pool->cache() == NULL, "constant pool cache must not be set yet");
duke@435: 
duke@435:   // determine index maps for methodOop rewriting
duke@435:   intArray* index_map         = NULL;
duke@435:   intStack* inverse_index_map = NULL;
duke@435:   compute_index_maps(pool, index_map, inverse_index_map);
duke@435: 
duke@435:   // allocate constant pool cache
duke@435:   constantPoolCacheHandle cache = new_constant_pool_cache(*inverse_index_map, CHECK);
duke@435:   pool->set_cache(cache());
duke@435:   cache->set_constant_pool(pool());
duke@435: 
duke@435:   if (RegisterFinalizersAtInit && klass->name() == vmSymbols::java_lang_Object()) {
duke@435:     int i = methods->length();
duke@435:     while (i-- > 0) {
duke@435:       methodOop method = (methodOop)methods->obj_at(i);
duke@435:       if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
duke@435:         // rewrite the return bytecodes of Object.<init> to register the
duke@435:         // object for finalization if needed.
duke@435:         methodHandle m(THREAD, method);
duke@435:         rewrite_Object_init(m, CHECK);
duke@435:         break;
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   // rewrite methods
duke@435:   { int i = methods->length();
duke@435:     while (i-- > 0) {
duke@435:       methodHandle m(THREAD, (methodOop)methods->obj_at(i));
duke@435:       m = rewrite_method(m, *index_map, CHECK);
duke@435:       // Method might have gotten rewritten.
duke@435:       methods->obj_at_put(i, m());
duke@435:     }
duke@435:   }
duke@435: }