| /* |
| * Copyright 1998-2005 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. |
| * |
| */ |
| |
| # include "incls/_precompiled.incl" |
| # include "incls/_rewriter.cpp.incl" |
| |
| |
| // Computes an index_map (new_index -> original_index) for contant pool entries |
| // that are referred to by the interpreter at runtime via the constant pool cache. |
| void Rewriter::compute_index_maps(constantPoolHandle pool, intArray*& index_map, intStack*& inverse_index_map) { |
| const int length = pool->length(); |
| index_map = new intArray(length, -1); |
| // Choose an initial value large enough that we don't get frequent |
| // calls to grow(). |
| inverse_index_map = new intStack(length / 2); |
| for (int i = 0; i < length; i++) { |
| switch (pool->tag_at(i).value()) { |
| case JVM_CONSTANT_Fieldref : // fall through |
| case JVM_CONSTANT_Methodref : // fall through |
| case JVM_CONSTANT_InterfaceMethodref: { |
| index_map->at_put(i, inverse_index_map->length()); |
| inverse_index_map->append(i); |
| } |
| } |
| } |
| } |
| |
| |
| // Creates a constant pool cache given an inverse_index_map |
| constantPoolCacheHandle Rewriter::new_constant_pool_cache(intArray& inverse_index_map, TRAPS) { |
| const int length = inverse_index_map.length(); |
| constantPoolCacheOop cache = oopFactory::new_constantPoolCache(length, CHECK_(constantPoolCacheHandle())); |
| cache->initialize(inverse_index_map); |
| return constantPoolCacheHandle(THREAD, cache); |
| } |
| |
| |
| |
| // The new finalization semantics says that registration of |
| // finalizable objects must be performed on successful return from the |
| // Object.<init> constructor. We could implement this trivially if |
| // <init> were never rewritten but since JVMTI allows this to occur, a |
| // more complicated solution is required. A special return bytecode |
| // is used only by Object.<init> to signal the finalization |
| // registration point. Additionally local 0 must be preserved so it's |
| // available to pass to the registration function. For simplicty we |
| // require that local 0 is never overwritten so it's available as an |
| // argument for registration. |
| |
| void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) { |
| RawBytecodeStream bcs(method); |
| while (!bcs.is_last_bytecode()) { |
| Bytecodes::Code opcode = bcs.raw_next(); |
| switch (opcode) { |
| case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break; |
| |
| case Bytecodes::_istore: |
| case Bytecodes::_lstore: |
| case Bytecodes::_fstore: |
| case Bytecodes::_dstore: |
| case Bytecodes::_astore: |
| if (bcs.get_index() != 0) continue; |
| |
| // fall through |
| case Bytecodes::_istore_0: |
| case Bytecodes::_lstore_0: |
| case Bytecodes::_fstore_0: |
| case Bytecodes::_dstore_0: |
| case Bytecodes::_astore_0: |
| THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(), |
| "can't overwrite local 0 in Object.<init>"); |
| break; |
| } |
| } |
| } |
| |
| |
| // Rewrites a method given the index_map information |
| methodHandle Rewriter::rewrite_method(methodHandle method, intArray& index_map, TRAPS) { |
| |
| int nof_jsrs = 0; |
| bool has_monitor_bytecodes = false; |
| |
| { |
| // We cannot tolerate a GC in this block, because we've |
| // cached the bytecodes in 'code_base'. If the methodOop |
| // moves, the bytecodes will also move. |
| No_Safepoint_Verifier nsv; |
| Bytecodes::Code c; |
| |
| // Bytecodes and their length |
| const address code_base = method->code_base(); |
| const int code_length = method->code_size(); |
| |
| int bc_length; |
| for (int bci = 0; bci < code_length; bci += bc_length) { |
| address bcp = code_base + bci; |
| c = (Bytecodes::Code)(*bcp); |
| |
| // Since we have the code, see if we can get the length |
| // directly. Some more complicated bytecodes will report |
| // a length of zero, meaning we need to make another method |
| // call to calculate the length. |
| bc_length = Bytecodes::length_for(c); |
| if (bc_length == 0) { |
| bc_length = Bytecodes::length_at(bcp); |
| |
| // length_at will put us at the bytecode after the one modified |
| // by 'wide'. We don't currently examine any of the bytecodes |
| // modified by wide, but in case we do in the future... |
| if (c == Bytecodes::_wide) { |
| c = (Bytecodes::Code)bcp[1]; |
| } |
| } |
| |
| assert(bc_length != 0, "impossible bytecode length"); |
| |
| switch (c) { |
| case Bytecodes::_lookupswitch : { |
| #ifndef CC_INTERP |
| Bytecode_lookupswitch* bc = Bytecode_lookupswitch_at(bcp); |
| bc->set_code( |
| bc->number_of_pairs() < BinarySwitchThreshold |
| ? Bytecodes::_fast_linearswitch |
| : Bytecodes::_fast_binaryswitch |
| ); |
| #endif |
| break; |
| } |
| case Bytecodes::_getstatic : // fall through |
| case Bytecodes::_putstatic : // fall through |
| case Bytecodes::_getfield : // fall through |
| case Bytecodes::_putfield : // fall through |
| case Bytecodes::_invokevirtual : // fall through |
| case Bytecodes::_invokespecial : // fall through |
| case Bytecodes::_invokestatic : // fall through |
| case Bytecodes::_invokeinterface: { |
| address p = bcp + 1; |
| Bytes::put_native_u2(p, index_map[Bytes::get_Java_u2(p)]); |
| break; |
| } |
| case Bytecodes::_jsr : // fall through |
| case Bytecodes::_jsr_w : nof_jsrs++; break; |
| case Bytecodes::_monitorenter : // fall through |
| case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break; |
| } |
| } |
| } |
| |
| // Update access flags |
| if (has_monitor_bytecodes) { |
| method->set_has_monitor_bytecodes(); |
| } |
| |
| // The present of a jsr bytecode implies that the method might potentially |
| // have to be rewritten, so we run the oopMapGenerator on the method |
| if (nof_jsrs > 0) { |
| method->set_has_jsrs(); |
| ResolveOopMapConflicts romc(method); |
| methodHandle original_method = method; |
| method = romc.do_potential_rewrite(CHECK_(methodHandle())); |
| if (method() != original_method()) { |
| // Insert invalid bytecode into original methodOop and set |
| // interpreter entrypoint, so that a executing this method |
| // will manifest itself in an easy recognizable form. |
| address bcp = original_method->bcp_from(0); |
| *bcp = (u1)Bytecodes::_shouldnotreachhere; |
| int kind = Interpreter::method_kind(original_method); |
| original_method->set_interpreter_kind(kind); |
| } |
| |
| // Update monitor matching info. |
| if (romc.monitor_safe()) { |
| method->set_guaranteed_monitor_matching(); |
| } |
| } |
| |
| // Setup method entrypoints for compiler and interpreter |
| method->link_method(method, CHECK_(methodHandle())); |
| |
| return method; |
| } |
| |
| |
| void Rewriter::rewrite(instanceKlassHandle klass, TRAPS) { |
| // gather starting points |
| ResourceMark rm(THREAD); |
| constantPoolHandle pool (THREAD, klass->constants()); |
| objArrayHandle methods (THREAD, klass->methods()); |
| assert(pool->cache() == NULL, "constant pool cache must not be set yet"); |
| |
| // determine index maps for methodOop rewriting |
| intArray* index_map = NULL; |
| intStack* inverse_index_map = NULL; |
| compute_index_maps(pool, index_map, inverse_index_map); |
| |
| // allocate constant pool cache |
| constantPoolCacheHandle cache = new_constant_pool_cache(*inverse_index_map, CHECK); |
| pool->set_cache(cache()); |
| cache->set_constant_pool(pool()); |
| |
| if (RegisterFinalizersAtInit && klass->name() == vmSymbols::java_lang_Object()) { |
| int i = methods->length(); |
| while (i-- > 0) { |
| methodOop method = (methodOop)methods->obj_at(i); |
| if (method->intrinsic_id() == vmIntrinsics::_Object_init) { |
| // rewrite the return bytecodes of Object.<init> to register the |
| // object for finalization if needed. |
| methodHandle m(THREAD, method); |
| rewrite_Object_init(m, CHECK); |
| break; |
| } |
| } |
| } |
| |
| // rewrite methods |
| { int i = methods->length(); |
| while (i-- > 0) { |
| methodHandle m(THREAD, (methodOop)methods->obj_at(i)); |
| m = rewrite_method(m, *index_map, CHECK); |
| // Method might have gotten rewritten. |
| methods->obj_at_put(i, m()); |
| } |
| } |
| } |