diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/interpreter/rewriter.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/interpreter/rewriter.cpp Tue Sep 12 19:03:39 2017 +0200 @@ -0,0 +1,619 @@ +/* + * Copyright (c) 1998, 2017, 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 "gc/shared/gcLocker.hpp" +#include "interpreter/bytecodes.hpp" +#include "interpreter/interpreter.hpp" +#include "interpreter/rewriter.hpp" +#include "memory/metadataFactory.hpp" +#include "memory/metaspaceShared.hpp" +#include "memory/resourceArea.hpp" +#include "oops/generateOopMap.hpp" +#include "prims/methodHandles.hpp" + +// Computes a CPC map (new_index -> original_index) for constant pool entries +// that are referred to by the interpreter at runtime via the constant pool cache. +// Also computes a CP map (original_index -> new_index). +// Marks entries in CP which require additional processing. +void Rewriter::compute_index_maps() { + const int length = _pool->length(); + init_maps(length); + bool saw_mh_symbol = false; + for (int i = 0; i < length; i++) { + int tag = _pool->tag_at(i).value(); + switch (tag) { + case JVM_CONSTANT_InterfaceMethodref: + case JVM_CONSTANT_Fieldref : // fall through + case JVM_CONSTANT_Methodref : // fall through + add_cp_cache_entry(i); + break; + case JVM_CONSTANT_String: + case JVM_CONSTANT_MethodHandle : // fall through + case JVM_CONSTANT_MethodType : // fall through + add_resolved_references_entry(i); + break; + case JVM_CONSTANT_Utf8: + if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() || + _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) { + saw_mh_symbol = true; + } + break; + } + } + + // Record limits of resolved reference map for constant pool cache indices + record_map_limits(); + + guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1), + "all cp cache indexes fit in a u2"); + + if (saw_mh_symbol) { + _method_handle_invokers.at_grow(length, 0); + } +} + +// Unrewrite the bytecodes if an error occurs. +void Rewriter::restore_bytecodes() { + int len = _methods->length(); + bool invokespecial_error = false; + + for (int i = len-1; i >= 0; i--) { + Method* method = _methods->at(i); + scan_method(method, true, &invokespecial_error); + assert(!invokespecial_error, "reversing should not get an invokespecial error"); + } +} + +// Creates a constant pool cache given a CPC map +void Rewriter::make_constant_pool_cache(TRAPS) { + ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data(); + ConstantPoolCache* cache = + ConstantPoolCache::allocate(loader_data, _cp_cache_map, + _invokedynamic_cp_cache_map, + _invokedynamic_references_map, CHECK); + + // initialize object cache in constant pool + _pool->set_cache(cache); + cache->set_constant_pool(_pool()); + + // _resolved_references is stored in pool->cache(), so need to be done after + // the above lines. + _pool->initialize_resolved_references(loader_data, _resolved_references_map, + _resolved_reference_limit, + THREAD); + + // Clean up constant pool cache if initialize_resolved_references() failed. + if (HAS_PENDING_EXCEPTION) { + MetadataFactory::free_metadata(loader_data, cache); + _pool->set_cache(NULL); // so the verifier isn't confused + } + + DEBUG_ONLY( + if (DumpSharedSpaces) { + cache->verify_just_initialized(); + }) +} + + + +// The new finalization semantics says that registration of +// finalizable objects must be performed on successful return from the +// Object. constructor. We could implement this trivially if +// 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. to signal the finalization +// registration point. Additionally local 0 must be preserved so it's +// available to pass to the registration function. For simplicity we +// require that local 0 is never overwritten so it's available as an +// argument for registration. + +void Rewriter::rewrite_Object_init(const 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."); + break; + + default: + break; + } + } +} + + +// Rewrite a classfile-order CP index into a native-order CPC index. +void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) { + address p = bcp + offset; + if (!reverse) { + int cp_index = Bytes::get_Java_u2(p); + int cache_index = cp_entry_to_cp_cache(cp_index); + Bytes::put_native_u2(p, cache_index); + if (!_method_handle_invokers.is_empty()) + maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse); + } else { + int cache_index = Bytes::get_native_u2(p); + int pool_index = cp_cache_entry_pool_index(cache_index); + Bytes::put_Java_u2(p, pool_index); + if (!_method_handle_invokers.is_empty()) + maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse); + } +} + +// If the constant pool entry for invokespecial is InterfaceMethodref, +// we need to add a separate cpCache entry for its resolution, because it is +// different than the resolution for invokeinterface with InterfaceMethodref. +// These cannot share cpCache entries. +void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) { + address p = bcp + offset; + if (!reverse) { + int cp_index = Bytes::get_Java_u2(p); + if (_pool->tag_at(cp_index).is_interface_method()) { + int cache_index = add_invokespecial_cp_cache_entry(cp_index); + if (cache_index != (int)(jushort) cache_index) { + *invokespecial_error = true; + } + Bytes::put_native_u2(p, cache_index); + } else { + rewrite_member_reference(bcp, offset, reverse); + } + } else { + rewrite_member_reference(bcp, offset, reverse); + } +} + + +// Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.) +void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) { + if (!reverse) { + if ((*opc) == (u1)Bytecodes::_invokevirtual || + // allow invokespecial as an alias, although it would be very odd: + (*opc) == (u1)Bytecodes::_invokespecial) { + assert(_pool->tag_at(cp_index).is_method(), "wrong index"); + // Determine whether this is a signature-polymorphic method. + if (cp_index >= _method_handle_invokers.length()) return; + int status = _method_handle_invokers.at(cp_index); + assert(status >= -1 && status <= 1, "oob tri-state"); + if (status == 0) { + if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() && + MethodHandles::is_signature_polymorphic_name(SystemDictionary::MethodHandle_klass(), + _pool->name_ref_at(cp_index))) { + // we may need a resolved_refs entry for the appendix + add_invokedynamic_resolved_references_entries(cp_index, cache_index); + status = +1; + } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() && + MethodHandles::is_signature_polymorphic_name(SystemDictionary::VarHandle_klass(), + _pool->name_ref_at(cp_index))) { + // we may need a resolved_refs entry for the appendix + add_invokedynamic_resolved_references_entries(cp_index, cache_index); + status = +1; + } else { + status = -1; + } + _method_handle_invokers.at(cp_index) = status; + } + // We use a special internal bytecode for such methods (if non-static). + // The basic reason for this is that such methods need an extra "appendix" argument + // to transmit the call site's intended call type. + if (status > 0) { + (*opc) = (u1)Bytecodes::_invokehandle; + } + } + } else { + // Do not need to look at cp_index. + if ((*opc) == (u1)Bytecodes::_invokehandle) { + (*opc) = (u1)Bytecodes::_invokevirtual; + // Ignore corner case of original _invokespecial instruction. + // This is safe because (a) the signature polymorphic method was final, and + // (b) the implementation of MethodHandle will not call invokespecial on it. + } + } +} + + +void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) { + address p = bcp + offset; + assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode"); + if (!reverse) { + int cp_index = Bytes::get_Java_u2(p); + int cache_index = add_invokedynamic_cp_cache_entry(cp_index); + int resolved_index = add_invokedynamic_resolved_references_entries(cp_index, cache_index); + // Replace the trailing four bytes with a CPC index for the dynamic + // call site. Unlike other CPC entries, there is one per bytecode, + // not just one per distinct CP entry. In other words, the + // CPC-to-CP relation is many-to-one for invokedynamic entries. + // This means we must use a larger index size than u2 to address + // all these entries. That is the main reason invokedynamic + // must have a five-byte instruction format. (Of course, other JVM + // implementations can use the bytes for other purposes.) + // Note: We use native_u4 format exclusively for 4-byte indexes. + Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index)); + // add the bcp in case we need to patch this bytecode if we also find a + // invokespecial/InterfaceMethodref in the bytecode stream + _patch_invokedynamic_bcps->push(p); + _patch_invokedynamic_refs->push(resolved_index); + } else { + int cache_index = ConstantPool::decode_invokedynamic_index( + Bytes::get_native_u4(p)); + // We will reverse the bytecode rewriting _after_ adjusting them. + // Adjust the cache index by offset to the invokedynamic entries in the + // cpCache plus the delta if the invokedynamic bytecodes were adjusted. + int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit; + int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment); + assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index"); + // zero out 4 bytes + Bytes::put_Java_u4(p, 0); + Bytes::put_Java_u2(p, cp_index); + } +} + +void Rewriter::patch_invokedynamic_bytecodes() { + // If the end of the cp_cache is the same as after initializing with the + // cpool, nothing needs to be done. Invokedynamic bytecodes are at the + // correct offsets. ie. no invokespecials added + int delta = cp_cache_delta(); + if (delta > 0) { + int length = _patch_invokedynamic_bcps->length(); + assert(length == _patch_invokedynamic_refs->length(), + "lengths should match"); + for (int i = 0; i < length; i++) { + address p = _patch_invokedynamic_bcps->at(i); + int cache_index = ConstantPool::decode_invokedynamic_index( + Bytes::get_native_u4(p)); + Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta)); + + // invokedynamic resolved references map also points to cp cache and must + // add delta to each. + int resolved_index = _patch_invokedynamic_refs->at(i); + for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) { + assert(_invokedynamic_references_map.at(resolved_index + entry) == cache_index, + "should be the same index"); + _invokedynamic_references_map.at_put(resolved_index+entry, + cache_index + delta); + } + } + } +} + + +// Rewrite some ldc bytecodes to _fast_aldc +void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide, + bool reverse) { + if (!reverse) { + assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode"); + address p = bcp + offset; + int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p); + constantTag tag = _pool->tag_at(cp_index).value(); + if (tag.is_method_handle() || tag.is_method_type() || tag.is_string()) { + int ref_index = cp_entry_to_resolved_references(cp_index); + if (is_wide) { + (*bcp) = Bytecodes::_fast_aldc_w; + assert(ref_index == (u2)ref_index, "index overflow"); + Bytes::put_native_u2(p, ref_index); + } else { + (*bcp) = Bytecodes::_fast_aldc; + assert(ref_index == (u1)ref_index, "index overflow"); + (*p) = (u1)ref_index; + } + } + } else { + Bytecodes::Code rewritten_bc = + (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc); + if ((*bcp) == rewritten_bc) { + address p = bcp + offset; + int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p); + int pool_index = resolved_references_entry_to_pool_index(ref_index); + if (is_wide) { + (*bcp) = Bytecodes::_ldc_w; + assert(pool_index == (u2)pool_index, "index overflow"); + Bytes::put_Java_u2(p, pool_index); + } else { + (*bcp) = Bytecodes::_ldc; + assert(pool_index == (u1)pool_index, "index overflow"); + (*p) = (u1)pool_index; + } + } + } +} + + +// Rewrites a method given the index_map information +void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_error) { + + int nof_jsrs = 0; + bool has_monitor_bytecodes = false; + 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; + int prefix_length = 0; + 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(method, 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) { + prefix_length = 1; + c = (Bytecodes::Code)bcp[1]; + } + } + + assert(bc_length != 0, "impossible bytecode length"); + + switch (c) { + case Bytecodes::_lookupswitch : { +#ifndef CC_INTERP + Bytecode_lookupswitch bc(method, bcp); + (*bcp) = ( + bc.number_of_pairs() < BinarySwitchThreshold + ? Bytecodes::_fast_linearswitch + : Bytecodes::_fast_binaryswitch + ); +#endif + break; + } + case Bytecodes::_fast_linearswitch: + case Bytecodes::_fast_binaryswitch: { +#ifndef CC_INTERP + (*bcp) = Bytecodes::_lookupswitch; +#endif + break; + } + + case Bytecodes::_invokespecial : { + rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error); + break; + } + + case Bytecodes::_putstatic : + case Bytecodes::_putfield : { + if (!reverse) { + // Check if any final field of the class given as parameter is modified + // outside of initializer methods of the class. Fields that are modified + // are marked with a flag. For marked fields, the compilers do not perform + // constant folding (as the field can be changed after initialization). + // + // The check is performed after verification and only if verification has + // succeeded. Therefore, the class is guaranteed to be well-formed. + InstanceKlass* klass = method->method_holder(); + u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1); + constantPoolHandle cp(method->constants()); + Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index)); + + if (klass->name() == ref_class_name) { + Symbol* field_name = cp->name_ref_at(bc_index); + Symbol* field_sig = cp->signature_ref_at(bc_index); + + fieldDescriptor fd; + if (klass->find_field(field_name, field_sig, &fd) != NULL) { + if (fd.access_flags().is_final()) { + if (fd.access_flags().is_static()) { + if (!method->is_static_initializer()) { + fd.set_has_initialized_final_update(true); + } + } else { + if (!method->is_object_initializer()) { + fd.set_has_initialized_final_update(true); + } + } + } + } + } + } + } + // fall through + case Bytecodes::_getstatic : // fall through + case Bytecodes::_getfield : // fall through + case Bytecodes::_invokevirtual : // fall through + case Bytecodes::_invokestatic : + case Bytecodes::_invokeinterface: + case Bytecodes::_invokehandle : // if reverse=true + rewrite_member_reference(bcp, prefix_length+1, reverse); + break; + case Bytecodes::_invokedynamic: + rewrite_invokedynamic(bcp, prefix_length+1, reverse); + break; + case Bytecodes::_ldc: + case Bytecodes::_fast_aldc: // if reverse=true + maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse); + break; + case Bytecodes::_ldc_w: + case Bytecodes::_fast_aldc_w: // if reverse=true + maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse); + 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; + + default: 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(); + // Second pass will revisit this method. + assert(method->has_jsrs(), "didn't we just set this?"); + } +} + +// After constant pool is created, revisit methods containing jsrs. +methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) { + ResourceMark rm(THREAD); + ResolveOopMapConflicts romc(method); + methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle())); + // Update monitor matching info. + if (romc.monitor_safe()) { + new_method->set_guaranteed_monitor_matching(); + } + + return new_method; +} + +void Rewriter::rewrite_bytecodes(TRAPS) { + assert(_pool->cache() == NULL, "constant pool cache must not be set yet"); + + // determine index maps for Method* rewriting + compute_index_maps(); + + if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) { + bool did_rewrite = false; + int i = _methods->length(); + while (i-- > 0) { + Method* method = _methods->at(i); + if (method->intrinsic_id() == vmIntrinsics::_Object_init) { + // rewrite the return bytecodes of Object. to register the + // object for finalization if needed. + methodHandle m(THREAD, method); + rewrite_Object_init(m, CHECK); + did_rewrite = true; + break; + } + } + assert(did_rewrite, "must find Object:: to rewrite it"); + } + + // rewrite methods, in two passes + int len = _methods->length(); + bool invokespecial_error = false; + + for (int i = len-1; i >= 0; i--) { + Method* method = _methods->at(i); + scan_method(method, false, &invokespecial_error); + if (invokespecial_error) { + // If you get an error here, there is no reversing bytecodes + // This exception is stored for this class and no further attempt is + // made at verifying or rewriting. + THROW_MSG(vmSymbols::java_lang_InternalError(), + "This classfile overflows invokespecial for interfaces " + "and cannot be loaded"); + return; + } + } + + // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref + // entries had to be added. + patch_invokedynamic_bytecodes(); +} + +void Rewriter::rewrite(InstanceKlass* klass, TRAPS) { + if (!DumpSharedSpaces) { + assert(!MetaspaceShared::is_in_shared_space(klass), "archive methods must not be rewritten at run time"); + } + ResourceMark rm(THREAD); + Rewriter rw(klass, klass->constants(), klass->methods(), CHECK); + // (That's all, folks.) +} + +Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array* methods, TRAPS) + : _klass(klass), + _pool(cpool), + _methods(methods), + _cp_map(cpool->length()), + _cp_cache_map(cpool->length() / 2), + _reference_map(cpool->length()), + _resolved_references_map(cpool->length() / 2), + _invokedynamic_references_map(cpool->length() / 2), + _method_handle_invokers(cpool->length()), + _invokedynamic_cp_cache_map(cpool->length() / 4) +{ + + // Rewrite bytecodes - exception here exits. + rewrite_bytecodes(CHECK); + + // Stress restoring bytecodes + if (StressRewriter) { + restore_bytecodes(); + rewrite_bytecodes(CHECK); + } + + // allocate constant pool cache, now that we've seen all the bytecodes + make_constant_pool_cache(THREAD); + + // Restore bytecodes to their unrewritten state if there are exceptions + // rewriting bytecodes or allocating the cpCache + if (HAS_PENDING_EXCEPTION) { + restore_bytecodes(); + return; + } + + // Relocate after everything, but still do this under the is_rewritten flag, + // so methods with jsrs in custom class lists in aren't attempted to be + // rewritten in the RO section of the shared archive. + // Relocated bytecodes don't have to be restored, only the cp cache entries + int len = _methods->length(); + for (int i = len-1; i >= 0; i--) { + methodHandle m(THREAD, _methods->at(i)); + + if (m->has_jsrs()) { + m = rewrite_jsrs(m, THREAD); + // Restore bytecodes to their unrewritten state if there are exceptions + // relocating bytecodes. If some are relocated, that is ok because that + // doesn't affect constant pool to cpCache rewriting. + if (HAS_PENDING_EXCEPTION) { + restore_bytecodes(); + return; + } + // Method might have gotten rewritten. + methods->at_put(i, m()); + } + } +}