/* * Copyright (c) 1997, 2011, 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 "classfile/systemDictionary.hpp" #include "code/debugInfoRec.hpp" #include "code/nmethod.hpp" #include "code/pcDesc.hpp" #include "code/scopeDesc.hpp" #include "interpreter/bytecode.hpp" #include "interpreter/interpreter.hpp" #include "interpreter/oopMapCache.hpp" #include "memory/allocation.inline.hpp" #include "memory/oopFactory.hpp" #include "memory/resourceArea.hpp" #include "oops/methodOop.hpp" #include "oops/oop.inline.hpp" #include "prims/jvmtiThreadState.hpp" #include "runtime/biasedLocking.hpp" #include "runtime/compilationPolicy.hpp" #include "runtime/deoptimization.hpp" #include "runtime/interfaceSupport.hpp" #include "runtime/sharedRuntime.hpp" #include "runtime/signature.hpp" #include "runtime/stubRoutines.hpp" #include "runtime/thread.hpp" #include "runtime/vframe.hpp" #include "runtime/vframeArray.hpp" #include "runtime/vframe_hp.hpp" #include "utilities/events.hpp" #include "utilities/xmlstream.hpp" #ifdef TARGET_ARCH_x86 # include "vmreg_x86.inline.hpp" #endif #ifdef TARGET_ARCH_sparc # include "vmreg_sparc.inline.hpp" #endif #ifdef TARGET_ARCH_zero # include "vmreg_zero.inline.hpp" #endif #ifdef TARGET_ARCH_arm # include "vmreg_arm.inline.hpp" #endif #ifdef TARGET_ARCH_ppc # include "vmreg_ppc.inline.hpp" #endif #ifdef COMPILER2 #ifdef TARGET_ARCH_MODEL_x86_32 # include "adfiles/ad_x86_32.hpp" #endif #ifdef TARGET_ARCH_MODEL_x86_64 # include "adfiles/ad_x86_64.hpp" #endif #ifdef TARGET_ARCH_MODEL_sparc # include "adfiles/ad_sparc.hpp" #endif #ifdef TARGET_ARCH_MODEL_zero # include "adfiles/ad_zero.hpp" #endif #ifdef TARGET_ARCH_MODEL_arm # include "adfiles/ad_arm.hpp" #endif #ifdef TARGET_ARCH_MODEL_ppc # include "adfiles/ad_ppc.hpp" #endif #endif bool DeoptimizationMarker::_is_active = false; Deoptimization::UnrollBlock::UnrollBlock(int size_of_deoptimized_frame, int caller_adjustment, int caller_actual_parameters, int number_of_frames, intptr_t* frame_sizes, address* frame_pcs, BasicType return_type) { _size_of_deoptimized_frame = size_of_deoptimized_frame; _caller_adjustment = caller_adjustment; _caller_actual_parameters = caller_actual_parameters; _number_of_frames = number_of_frames; _frame_sizes = frame_sizes; _frame_pcs = frame_pcs; _register_block = NEW_C_HEAP_ARRAY(intptr_t, RegisterMap::reg_count * 2); _return_type = return_type; _initial_fp = 0; // PD (x86 only) _counter_temp = 0; _unpack_kind = 0; _sender_sp_temp = 0; _total_frame_sizes = size_of_frames(); } Deoptimization::UnrollBlock::~UnrollBlock() { FREE_C_HEAP_ARRAY(intptr_t, _frame_sizes); FREE_C_HEAP_ARRAY(intptr_t, _frame_pcs); FREE_C_HEAP_ARRAY(intptr_t, _register_block); } intptr_t* Deoptimization::UnrollBlock::value_addr_at(int register_number) const { assert(register_number < RegisterMap::reg_count, "checking register number"); return &_register_block[register_number * 2]; } int Deoptimization::UnrollBlock::size_of_frames() const { // Acount first for the adjustment of the initial frame int result = _caller_adjustment; for (int index = 0; index < number_of_frames(); index++) { result += frame_sizes()[index]; } return result; } void Deoptimization::UnrollBlock::print() { ttyLocker ttyl; tty->print_cr("UnrollBlock"); tty->print_cr(" size_of_deoptimized_frame = %d", _size_of_deoptimized_frame); tty->print( " frame_sizes: "); for (int index = 0; index < number_of_frames(); index++) { tty->print("%d ", frame_sizes()[index]); } tty->cr(); } // In order to make fetch_unroll_info work properly with escape // analysis, The method was changed from JRT_LEAF to JRT_BLOCK_ENTRY and // ResetNoHandleMark and HandleMark were removed from it. The actual reallocation // of previously eliminated objects occurs in realloc_objects, which is // called from the method fetch_unroll_info_helper below. JRT_BLOCK_ENTRY(Deoptimization::UnrollBlock*, Deoptimization::fetch_unroll_info(JavaThread* thread)) // It is actually ok to allocate handles in a leaf method. It causes no safepoints, // but makes the entry a little slower. There is however a little dance we have to // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro // fetch_unroll_info() is called at the beginning of the deoptimization // handler. Note this fact before we start generating temporary frames // that can confuse an asynchronous stack walker. This counter is // decremented at the end of unpack_frames(). thread->inc_in_deopt_handler(); return fetch_unroll_info_helper(thread); JRT_END // This is factored, since it is both called from a JRT_LEAF (deoptimization) and a JRT_ENTRY (uncommon_trap) Deoptimization::UnrollBlock* Deoptimization::fetch_unroll_info_helper(JavaThread* thread) { // Note: there is a safepoint safety issue here. No matter whether we enter // via vanilla deopt or uncommon trap we MUST NOT stop at a safepoint once // the vframeArray is created. // // Allocate our special deoptimization ResourceMark DeoptResourceMark* dmark = new DeoptResourceMark(thread); assert(thread->deopt_mark() == NULL, "Pending deopt!"); thread->set_deopt_mark(dmark); frame stub_frame = thread->last_frame(); // Makes stack walkable as side effect RegisterMap map(thread, true); RegisterMap dummy_map(thread, false); // Now get the deoptee with a valid map frame deoptee = stub_frame.sender(&map); // Set the deoptee nmethod assert(thread->deopt_nmethod() == NULL, "Pending deopt!"); thread->set_deopt_nmethod(deoptee.cb()->as_nmethod_or_null()); if (VerifyStack) { thread->validate_frame_layout(); } // Create a growable array of VFrames where each VFrame represents an inlined // Java frame. This storage is allocated with the usual system arena. assert(deoptee.is_compiled_frame(), "Wrong frame type"); GrowableArray* chunk = new GrowableArray(10); vframe* vf = vframe::new_vframe(&deoptee, &map, thread); while (!vf->is_top()) { assert(vf->is_compiled_frame(), "Wrong frame type"); chunk->push(compiledVFrame::cast(vf)); vf = vf->sender(); } assert(vf->is_compiled_frame(), "Wrong frame type"); chunk->push(compiledVFrame::cast(vf)); #ifdef COMPILER2 // Reallocate the non-escaping objects and restore their fields. Then // relock objects if synchronization on them was eliminated. if (DoEscapeAnalysis) { if (EliminateAllocations) { assert (chunk->at(0)->scope() != NULL,"expect only compiled java frames"); GrowableArray* objects = chunk->at(0)->scope()->objects(); // The flag return_oop() indicates call sites which return oop // in compiled code. Such sites include java method calls, // runtime calls (for example, used to allocate new objects/arrays // on slow code path) and any other calls generated in compiled code. // It is not guaranteed that we can get such information here only // by analyzing bytecode in deoptimized frames. This is why this flag // is set during method compilation (see Compile::Process_OopMap_Node()). bool save_oop_result = chunk->at(0)->scope()->return_oop(); Handle return_value; if (save_oop_result) { // Reallocation may trigger GC. If deoptimization happened on return from // call which returns oop we need to save it since it is not in oopmap. oop result = deoptee.saved_oop_result(&map); assert(result == NULL || result->is_oop(), "must be oop"); return_value = Handle(thread, result); assert(Universe::heap()->is_in_or_null(result), "must be heap pointer"); if (TraceDeoptimization) { tty->print_cr("SAVED OOP RESULT " INTPTR_FORMAT " in thread " INTPTR_FORMAT, result, thread); } } bool reallocated = false; if (objects != NULL) { JRT_BLOCK reallocated = realloc_objects(thread, &deoptee, objects, THREAD); JRT_END } if (reallocated) { reassign_fields(&deoptee, &map, objects); #ifndef PRODUCT if (TraceDeoptimization) { ttyLocker ttyl; tty->print_cr("REALLOC OBJECTS in thread " INTPTR_FORMAT, thread); print_objects(objects); } #endif } if (save_oop_result) { // Restore result. deoptee.set_saved_oop_result(&map, return_value()); } } if (EliminateLocks) { #ifndef PRODUCT bool first = true; #endif for (int i = 0; i < chunk->length(); i++) { compiledVFrame* cvf = chunk->at(i); assert (cvf->scope() != NULL,"expect only compiled java frames"); GrowableArray* monitors = cvf->monitors(); if (monitors->is_nonempty()) { relock_objects(monitors, thread); #ifndef PRODUCT if (TraceDeoptimization) { ttyLocker ttyl; for (int j = 0; j < monitors->length(); j++) { MonitorInfo* mi = monitors->at(j); if (mi->eliminated()) { if (first) { first = false; tty->print_cr("RELOCK OBJECTS in thread " INTPTR_FORMAT, thread); } tty->print_cr(" object <" INTPTR_FORMAT "> locked", mi->owner()); } } } #endif } } } } #endif // COMPILER2 // Ensure that no safepoint is taken after pointers have been stored // in fields of rematerialized objects. If a safepoint occurs from here on // out the java state residing in the vframeArray will be missed. No_Safepoint_Verifier no_safepoint; vframeArray* array = create_vframeArray(thread, deoptee, &map, chunk); assert(thread->vframe_array_head() == NULL, "Pending deopt!");; thread->set_vframe_array_head(array); // Now that the vframeArray has been created if we have any deferred local writes // added by jvmti then we can free up that structure as the data is now in the // vframeArray if (thread->deferred_locals() != NULL) { GrowableArray* list = thread->deferred_locals(); int i = 0; do { // Because of inlining we could have multiple vframes for a single frame // and several of the vframes could have deferred writes. Find them all. if (list->at(i)->id() == array->original().id()) { jvmtiDeferredLocalVariableSet* dlv = list->at(i); list->remove_at(i); // individual jvmtiDeferredLocalVariableSet are CHeapObj's delete dlv; } else { i++; } } while ( i < list->length() ); if (list->length() == 0) { thread->set_deferred_locals(NULL); // free the list and elements back to C heap. delete list; } } #ifndef SHARK // Compute the caller frame based on the sender sp of stub_frame and stored frame sizes info. CodeBlob* cb = stub_frame.cb(); // Verify we have the right vframeArray assert(cb->frame_size() >= 0, "Unexpected frame size"); intptr_t* unpack_sp = stub_frame.sp() + cb->frame_size(); // If the deopt call site is a MethodHandle invoke call site we have // to adjust the unpack_sp. nmethod* deoptee_nm = deoptee.cb()->as_nmethod_or_null(); if (deoptee_nm != NULL && deoptee_nm->is_method_handle_return(deoptee.pc())) unpack_sp = deoptee.unextended_sp(); #ifdef ASSERT assert(cb->is_deoptimization_stub() || cb->is_uncommon_trap_stub(), "just checking"); Events::log("fetch unroll sp " INTPTR_FORMAT, unpack_sp); #endif #else intptr_t* unpack_sp = stub_frame.sender(&dummy_map).unextended_sp(); #endif // !SHARK // This is a guarantee instead of an assert because if vframe doesn't match // we will unpack the wrong deoptimized frame and wind up in strange places // where it will be very difficult to figure out what went wrong. Better // to die an early death here than some very obscure death later when the // trail is cold. // Note: on ia64 this guarantee can be fooled by frames with no memory stack // in that it will fail to detect a problem when there is one. This needs // more work in tiger timeframe. guarantee(array->unextended_sp() == unpack_sp, "vframe_array_head must contain the vframeArray to unpack"); int number_of_frames = array->frames(); // Compute the vframes' sizes. Note that frame_sizes[] entries are ordered from outermost to innermost // virtual activation, which is the reverse of the elements in the vframes array. intptr_t* frame_sizes = NEW_C_HEAP_ARRAY(intptr_t, number_of_frames); // +1 because we always have an interpreter return address for the final slot. address* frame_pcs = NEW_C_HEAP_ARRAY(address, number_of_frames + 1); int callee_parameters = 0; int callee_locals = 0; int popframe_extra_args = 0; // Create an interpreter return address for the stub to use as its return // address so the skeletal frames are perfectly walkable frame_pcs[number_of_frames] = Interpreter::deopt_entry(vtos, 0); // PopFrame requires that the preserved incoming arguments from the recently-popped topmost // activation be put back on the expression stack of the caller for reexecution if (JvmtiExport::can_pop_frame() && thread->popframe_forcing_deopt_reexecution()) { popframe_extra_args = in_words(thread->popframe_preserved_args_size_in_words()); } // Find the current pc for sender of the deoptee. Since the sender may have been deoptimized // itself since the deoptee vframeArray was created we must get a fresh value of the pc rather // than simply use array->sender.pc(). This requires us to walk the current set of frames // frame deopt_sender = stub_frame.sender(&dummy_map); // First is the deoptee frame deopt_sender = deopt_sender.sender(&dummy_map); // Now deoptee caller // It's possible that the number of paramters at the call site is // different than number of arguments in the callee when method // handles are used. If the caller is interpreted get the real // value so that the proper amount of space can be added to it's // frame. int caller_actual_parameters = callee_parameters; if (deopt_sender.is_interpreted_frame()) { methodHandle method = deopt_sender.interpreter_frame_method(); Bytecode_invoke cur = Bytecode_invoke_check(method, deopt_sender.interpreter_frame_bci()); Symbol* signature = method->constants()->signature_ref_at(cur.index()); ArgumentSizeComputer asc(signature); caller_actual_parameters = asc.size() + (cur.has_receiver() ? 1 : 0); } // // frame_sizes/frame_pcs[0] oldest frame (int or c2i) // frame_sizes/frame_pcs[1] next oldest frame (int) // frame_sizes/frame_pcs[n] youngest frame (int) // // Now a pc in frame_pcs is actually the return address to the frame's caller (a frame // owns the space for the return address to it's caller). Confusing ain't it. // // The vframe array can address vframes with indices running from // 0.._frames-1. Index 0 is the youngest frame and _frame - 1 is the oldest (root) frame. // When we create the skeletal frames we need the oldest frame to be in the zero slot // in the frame_sizes/frame_pcs so the assembly code can do a trivial walk. // so things look a little strange in this loop. // for (int index = 0; index < array->frames(); index++ ) { // frame[number_of_frames - 1 ] = on_stack_size(youngest) // frame[number_of_frames - 2 ] = on_stack_size(sender(youngest)) // frame[number_of_frames - 3 ] = on_stack_size(sender(sender(youngest))) int caller_parms = callee_parameters; if (index == array->frames() - 1) { // Use the value from the interpreted caller caller_parms = caller_actual_parameters; } frame_sizes[number_of_frames - 1 - index] = BytesPerWord * array->element(index)->on_stack_size(caller_parms, callee_parameters, callee_locals, index == 0, popframe_extra_args); // This pc doesn't have to be perfect just good enough to identify the frame // as interpreted so the skeleton frame will be walkable // The correct pc will be set when the skeleton frame is completely filled out // The final pc we store in the loop is wrong and will be overwritten below frame_pcs[number_of_frames - 1 - index ] = Interpreter::deopt_entry(vtos, 0) - frame::pc_return_offset; callee_parameters = array->element(index)->method()->size_of_parameters(); callee_locals = array->element(index)->method()->max_locals(); popframe_extra_args = 0; } // Compute whether the root vframe returns a float or double value. BasicType return_type; { HandleMark hm; methodHandle method(thread, array->element(0)->method()); Bytecode_invoke invoke = Bytecode_invoke_check(method, array->element(0)->bci()); return_type = invoke.is_valid() ? invoke.result_type() : T_ILLEGAL; } // Compute information for handling adapters and adjusting the frame size of the caller. int caller_adjustment = 0; // Compute the amount the oldest interpreter frame will have to adjust // its caller's stack by. If the caller is a compiled frame then // we pretend that the callee has no parameters so that the // extension counts for the full amount of locals and not just // locals-parms. This is because without a c2i adapter the parm // area as created by the compiled frame will not be usable by // the interpreter. (Depending on the calling convention there // may not even be enough space). // QQQ I'd rather see this pushed down into last_frame_adjust // and have it take the sender (aka caller). if (deopt_sender.is_compiled_frame()) { caller_adjustment = last_frame_adjust(0, callee_locals); } else if (callee_locals > caller_actual_parameters) { // The caller frame may need extending to accommodate // non-parameter locals of the first unpacked interpreted frame. // Compute that adjustment. caller_adjustment = last_frame_adjust(caller_actual_parameters, callee_locals); } // If the sender is deoptimized the we must retrieve the address of the handler // since the frame will "magically" show the original pc before the deopt // and we'd undo the deopt. frame_pcs[0] = deopt_sender.raw_pc(); #ifndef SHARK assert(CodeCache::find_blob_unsafe(frame_pcs[0]) != NULL, "bad pc"); #endif // SHARK UnrollBlock* info = new UnrollBlock(array->frame_size() * BytesPerWord, caller_adjustment * BytesPerWord, caller_actual_parameters, number_of_frames, frame_sizes, frame_pcs, return_type); // On some platforms, we need a way to pass fp to the unpacking code // so the skeletal frames come out correct. info->set_initial_fp((intptr_t) array->sender().fp()); if (array->frames() > 1) { if (VerifyStack && TraceDeoptimization) { tty->print_cr("Deoptimizing method containing inlining"); } } array->set_unroll_block(info); return info; } // Called to cleanup deoptimization data structures in normal case // after unpacking to stack and when stack overflow error occurs void Deoptimization::cleanup_deopt_info(JavaThread *thread, vframeArray *array) { // Get array if coming from exception if (array == NULL) { array = thread->vframe_array_head(); } thread->set_vframe_array_head(NULL); // Free the previous UnrollBlock vframeArray* old_array = thread->vframe_array_last(); thread->set_vframe_array_last(array); if (old_array != NULL) { UnrollBlock* old_info = old_array->unroll_block(); old_array->set_unroll_block(NULL); delete old_info; delete old_array; } // Deallocate any resource creating in this routine and any ResourceObjs allocated // inside the vframeArray (StackValueCollections) delete thread->deopt_mark(); thread->set_deopt_mark(NULL); thread->set_deopt_nmethod(NULL); if (JvmtiExport::can_pop_frame()) { #ifndef CC_INTERP // Regardless of whether we entered this routine with the pending // popframe condition bit set, we should always clear it now thread->clear_popframe_condition(); #else // C++ interpeter will clear has_pending_popframe when it enters // with method_resume. For deopt_resume2 we clear it now. if (thread->popframe_forcing_deopt_reexecution()) thread->clear_popframe_condition(); #endif /* CC_INTERP */ } // unpack_frames() is called at the end of the deoptimization handler // and (in C2) at the end of the uncommon trap handler. Note this fact // so that an asynchronous stack walker can work again. This counter is // incremented at the beginning of fetch_unroll_info() and (in C2) at // the beginning of uncommon_trap(). thread->dec_in_deopt_handler(); } // Return BasicType of value being returned JRT_LEAF(BasicType, Deoptimization::unpack_frames(JavaThread* thread, int exec_mode)) // We are already active int he special DeoptResourceMark any ResourceObj's we // allocate will be freed at the end of the routine. // It is actually ok to allocate handles in a leaf method. It causes no safepoints, // but makes the entry a little slower. There is however a little dance we have to // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro ResetNoHandleMark rnhm; // No-op in release/product versions HandleMark hm; frame stub_frame = thread->last_frame(); // Since the frame to unpack is the top frame of this thread, the vframe_array_head // must point to the vframeArray for the unpack frame. vframeArray* array = thread->vframe_array_head(); #ifndef PRODUCT if (TraceDeoptimization) { tty->print_cr("DEOPT UNPACKING thread " INTPTR_FORMAT " vframeArray " INTPTR_FORMAT " mode %d", thread, array, exec_mode); } #endif UnrollBlock* info = array->unroll_block(); // Unpack the interpreter frames and any adapter frame (c2 only) we might create. array->unpack_to_stack(stub_frame, exec_mode, info->caller_actual_parameters()); BasicType bt = info->return_type(); // If we have an exception pending, claim that the return type is an oop // so the deopt_blob does not overwrite the exception_oop. if (exec_mode == Unpack_exception) bt = T_OBJECT; // Cleanup thread deopt data cleanup_deopt_info(thread, array); #ifndef PRODUCT if (VerifyStack) { ResourceMark res_mark; thread->validate_frame_layout(); // Verify that the just-unpacked frames match the interpreter's // notions of expression stack and locals vframeArray* cur_array = thread->vframe_array_last(); RegisterMap rm(thread, false); rm.set_include_argument_oops(false); bool is_top_frame = true; int callee_size_of_parameters = 0; int callee_max_locals = 0; for (int i = 0; i < cur_array->frames(); i++) { vframeArrayElement* el = cur_array->element(i); frame* iframe = el->iframe(); guarantee(iframe->is_interpreted_frame(), "Wrong frame type"); // Get the oop map for this bci InterpreterOopMap mask; int cur_invoke_parameter_size = 0; bool try_next_mask = false; int next_mask_expression_stack_size = -1; int top_frame_expression_stack_adjustment = 0; methodHandle mh(thread, iframe->interpreter_frame_method()); OopMapCache::compute_one_oop_map(mh, iframe->interpreter_frame_bci(), &mask); BytecodeStream str(mh); str.set_start(iframe->interpreter_frame_bci()); int max_bci = mh->code_size(); // Get to the next bytecode if possible assert(str.bci() < max_bci, "bci in interpreter frame out of bounds"); // Check to see if we can grab the number of outgoing arguments // at an uncommon trap for an invoke (where the compiler // generates debug info before the invoke has executed) Bytecodes::Code cur_code = str.next(); if (cur_code == Bytecodes::_invokevirtual || cur_code == Bytecodes::_invokespecial || cur_code == Bytecodes::_invokestatic || cur_code == Bytecodes::_invokeinterface) { Bytecode_invoke invoke(mh, iframe->interpreter_frame_bci()); Symbol* signature = invoke.signature(); ArgumentSizeComputer asc(signature); cur_invoke_parameter_size = asc.size(); if (cur_code != Bytecodes::_invokestatic) { // Add in receiver ++cur_invoke_parameter_size; } } if (str.bci() < max_bci) { Bytecodes::Code bc = str.next(); if (bc >= 0) { // The interpreter oop map generator reports results before // the current bytecode has executed except in the case of // calls. It seems to be hard to tell whether the compiler // has emitted debug information matching the "state before" // a given bytecode or the state after, so we try both switch (cur_code) { case Bytecodes::_invokevirtual: case Bytecodes::_invokespecial: case Bytecodes::_invokestatic: case Bytecodes::_invokeinterface: case Bytecodes::_athrow: break; default: { InterpreterOopMap next_mask; OopMapCache::compute_one_oop_map(mh, str.bci(), &next_mask); next_mask_expression_stack_size = next_mask.expression_stack_size(); // Need to subtract off the size of the result type of // the bytecode because this is not described in the // debug info but returned to the interpreter in the TOS // caching register BasicType bytecode_result_type = Bytecodes::result_type(cur_code); if (bytecode_result_type != T_ILLEGAL) { top_frame_expression_stack_adjustment = type2size[bytecode_result_type]; } assert(top_frame_expression_stack_adjustment >= 0, ""); try_next_mask = true; break; } } } } // Verify stack depth and oops in frame // This assertion may be dependent on the platform we're running on and may need modification (tested on x86 and sparc) if (!( /* SPARC */ (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_size_of_parameters) || /* x86 */ (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_max_locals) || (try_next_mask && (iframe->interpreter_frame_expression_stack_size() == (next_mask_expression_stack_size - top_frame_expression_stack_adjustment))) || (is_top_frame && (exec_mode == Unpack_exception) && iframe->interpreter_frame_expression_stack_size() == 0) || (is_top_frame && (exec_mode == Unpack_uncommon_trap || exec_mode == Unpack_reexecute) && (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + cur_invoke_parameter_size)) )) { ttyLocker ttyl; // Print out some information that will help us debug the problem tty->print_cr("Wrong number of expression stack elements during deoptimization"); tty->print_cr(" Error occurred while verifying frame %d (0..%d, 0 is topmost)", i, cur_array->frames() - 1); tty->print_cr(" Fabricated interpreter frame had %d expression stack elements", iframe->interpreter_frame_expression_stack_size()); tty->print_cr(" Interpreter oop map had %d expression stack elements", mask.expression_stack_size()); tty->print_cr(" try_next_mask = %d", try_next_mask); tty->print_cr(" next_mask_expression_stack_size = %d", next_mask_expression_stack_size); tty->print_cr(" callee_size_of_parameters = %d", callee_size_of_parameters); tty->print_cr(" callee_max_locals = %d", callee_max_locals); tty->print_cr(" top_frame_expression_stack_adjustment = %d", top_frame_expression_stack_adjustment); tty->print_cr(" exec_mode = %d", exec_mode); tty->print_cr(" cur_invoke_parameter_size = %d", cur_invoke_parameter_size); tty->print_cr(" Thread = " INTPTR_FORMAT ", thread ID = " UINTX_FORMAT, thread, thread->osthread()->thread_id()); tty->print_cr(" Interpreted frames:"); for (int k = 0; k < cur_array->frames(); k++) { vframeArrayElement* el = cur_array->element(k); tty->print_cr(" %s (bci %d)", el->method()->name_and_sig_as_C_string(), el->bci()); } cur_array->print_on_2(tty); guarantee(false, "wrong number of expression stack elements during deopt"); } VerifyOopClosure verify; iframe->oops_interpreted_do(&verify, &rm, false); callee_size_of_parameters = mh->size_of_parameters(); callee_max_locals = mh->max_locals(); is_top_frame = false; } } #endif /* !PRODUCT */ return bt; JRT_END int Deoptimization::deoptimize_dependents() { Threads::deoptimized_wrt_marked_nmethods(); return 0; } #ifdef COMPILER2 bool Deoptimization::realloc_objects(JavaThread* thread, frame* fr, GrowableArray* objects, TRAPS) { Handle pending_exception(thread->pending_exception()); const char* exception_file = thread->exception_file(); int exception_line = thread->exception_line(); thread->clear_pending_exception(); for (int i = 0; i < objects->length(); i++) { assert(objects->at(i)->is_object(), "invalid debug information"); ObjectValue* sv = (ObjectValue*) objects->at(i); KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()()); oop obj = NULL; if (k->oop_is_instance()) { instanceKlass* ik = instanceKlass::cast(k()); obj = ik->allocate_instance(CHECK_(false)); } else if (k->oop_is_typeArray()) { typeArrayKlass* ak = typeArrayKlass::cast(k()); assert(sv->field_size() % type2size[ak->element_type()] == 0, "non-integral array length"); int len = sv->field_size() / type2size[ak->element_type()]; obj = ak->allocate(len, CHECK_(false)); } else if (k->oop_is_objArray()) { objArrayKlass* ak = objArrayKlass::cast(k()); obj = ak->allocate(sv->field_size(), CHECK_(false)); } assert(obj != NULL, "allocation failed"); assert(sv->value().is_null(), "redundant reallocation"); sv->set_value(obj); } if (pending_exception.not_null()) { thread->set_pending_exception(pending_exception(), exception_file, exception_line); } return true; } // This assumes that the fields are stored in ObjectValue in the same order // they are yielded by do_nonstatic_fields. class FieldReassigner: public FieldClosure { frame* _fr; RegisterMap* _reg_map; ObjectValue* _sv; instanceKlass* _ik; oop _obj; int _i; public: FieldReassigner(frame* fr, RegisterMap* reg_map, ObjectValue* sv, oop obj) : _fr(fr), _reg_map(reg_map), _sv(sv), _obj(obj), _i(0) {} int i() const { return _i; } void do_field(fieldDescriptor* fd) { intptr_t val; StackValue* value = StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(i())); int offset = fd->offset(); switch (fd->field_type()) { case T_OBJECT: case T_ARRAY: assert(value->type() == T_OBJECT, "Agreement."); _obj->obj_field_put(offset, value->get_obj()()); break; case T_LONG: case T_DOUBLE: { assert(value->type() == T_INT, "Agreement."); StackValue* low = StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(++_i)); #ifdef _LP64 jlong res = (jlong)low->get_int(); #else #ifdef SPARC // For SPARC we have to swap high and low words. jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int()); #else jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int()); #endif //SPARC #endif _obj->long_field_put(offset, res); break; } // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem. case T_INT: case T_FLOAT: // 4 bytes. assert(value->type() == T_INT, "Agreement."); val = value->get_int(); _obj->int_field_put(offset, (jint)*((jint*)&val)); break; case T_SHORT: case T_CHAR: // 2 bytes assert(value->type() == T_INT, "Agreement."); val = value->get_int(); _obj->short_field_put(offset, (jshort)*((jint*)&val)); break; case T_BOOLEAN: case T_BYTE: // 1 byte assert(value->type() == T_INT, "Agreement."); val = value->get_int(); _obj->bool_field_put(offset, (jboolean)*((jint*)&val)); break; default: ShouldNotReachHere(); } _i++; } }; // restore elements of an eliminated type array void Deoptimization::reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type) { int index = 0; intptr_t val; for (int i = 0; i < sv->field_size(); i++) { StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i)); switch(type) { case T_LONG: case T_DOUBLE: { assert(value->type() == T_INT, "Agreement."); StackValue* low = StackValue::create_stack_value(fr, reg_map, sv->field_at(++i)); #ifdef _LP64 jlong res = (jlong)low->get_int(); #else #ifdef SPARC // For SPARC we have to swap high and low words. jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int()); #else jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int()); #endif //SPARC #endif obj->long_at_put(index, res); break; } // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem. case T_INT: case T_FLOAT: // 4 bytes. assert(value->type() == T_INT, "Agreement."); val = value->get_int(); obj->int_at_put(index, (jint)*((jint*)&val)); break; case T_SHORT: case T_CHAR: // 2 bytes assert(value->type() == T_INT, "Agreement."); val = value->get_int(); obj->short_at_put(index, (jshort)*((jint*)&val)); break; case T_BOOLEAN: case T_BYTE: // 1 byte assert(value->type() == T_INT, "Agreement."); val = value->get_int(); obj->bool_at_put(index, (jboolean)*((jint*)&val)); break; default: ShouldNotReachHere(); } index++; } } // restore fields of an eliminated object array void Deoptimization::reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj) { for (int i = 0; i < sv->field_size(); i++) { StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i)); assert(value->type() == T_OBJECT, "object element expected"); obj->obj_at_put(i, value->get_obj()()); } } // restore fields of all eliminated objects and arrays void Deoptimization::reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray* objects) { for (int i = 0; i < objects->length(); i++) { ObjectValue* sv = (ObjectValue*) objects->at(i); KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()()); Handle obj = sv->value(); assert(obj.not_null(), "reallocation was missed"); if (k->oop_is_instance()) { instanceKlass* ik = instanceKlass::cast(k()); FieldReassigner reassign(fr, reg_map, sv, obj()); ik->do_nonstatic_fields(&reassign); } else if (k->oop_is_typeArray()) { typeArrayKlass* ak = typeArrayKlass::cast(k()); reassign_type_array_elements(fr, reg_map, sv, (typeArrayOop) obj(), ak->element_type()); } else if (k->oop_is_objArray()) { reassign_object_array_elements(fr, reg_map, sv, (objArrayOop) obj()); } } } // relock objects for which synchronization was eliminated void Deoptimization::relock_objects(GrowableArray* monitors, JavaThread* thread) { for (int i = 0; i < monitors->length(); i++) { MonitorInfo* mon_info = monitors->at(i); if (mon_info->eliminated()) { assert(mon_info->owner() != NULL, "reallocation was missed"); Handle obj = Handle(mon_info->owner()); markOop mark = obj->mark(); if (UseBiasedLocking && mark->has_bias_pattern()) { // New allocated objects may have the mark set to anonymously biased. // Also the deoptimized method may called methods with synchronization // where the thread-local object is bias locked to the current thread. assert(mark->is_biased_anonymously() || mark->biased_locker() == thread, "should be locked to current thread"); // Reset mark word to unbiased prototype. markOop unbiased_prototype = markOopDesc::prototype()->set_age(mark->age()); obj->set_mark(unbiased_prototype); } BasicLock* lock = mon_info->lock(); ObjectSynchronizer::slow_enter(obj, lock, thread); } assert(mon_info->owner()->is_locked(), "object must be locked now"); } } #ifndef PRODUCT // print information about reallocated objects void Deoptimization::print_objects(GrowableArray* objects) { fieldDescriptor fd; for (int i = 0; i < objects->length(); i++) { ObjectValue* sv = (ObjectValue*) objects->at(i); KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()()); Handle obj = sv->value(); tty->print(" object <" INTPTR_FORMAT "> of type ", sv->value()()); k->as_klassOop()->print_value(); tty->print(" allocated (%d bytes)", obj->size() * HeapWordSize); tty->cr(); if (Verbose) { k->oop_print_on(obj(), tty); } } } #endif #endif // COMPILER2 vframeArray* Deoptimization::create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray* chunk) { #ifndef PRODUCT if (TraceDeoptimization) { ttyLocker ttyl; tty->print("DEOPT PACKING thread " INTPTR_FORMAT " ", thread); fr.print_on(tty); tty->print_cr(" Virtual frames (innermost first):"); for (int index = 0; index < chunk->length(); index++) { compiledVFrame* vf = chunk->at(index); tty->print(" %2d - ", index); vf->print_value(); int bci = chunk->at(index)->raw_bci(); const char* code_name; if (bci == SynchronizationEntryBCI) { code_name = "sync entry"; } else { Bytecodes::Code code = vf->method()->code_at(bci); code_name = Bytecodes::name(code); } tty->print(" - %s", code_name); tty->print_cr(" @ bci %d ", bci); if (Verbose) { vf->print(); tty->cr(); } } } #endif // Register map for next frame (used for stack crawl). We capture // the state of the deopt'ing frame's caller. Thus if we need to // stuff a C2I adapter we can properly fill in the callee-save // register locations. frame caller = fr.sender(reg_map); int frame_size = caller.sp() - fr.sp(); frame sender = caller; // Since the Java thread being deoptimized will eventually adjust it's own stack, // the vframeArray containing the unpacking information is allocated in the C heap. // For Compiler1, the caller of the deoptimized frame is saved for use by unpack_frames(). vframeArray* array = vframeArray::allocate(thread, frame_size, chunk, reg_map, sender, caller, fr); // Compare the vframeArray to the collected vframes assert(array->structural_compare(thread, chunk), "just checking"); Events::log("# vframes = %d", (intptr_t)chunk->length()); #ifndef PRODUCT if (TraceDeoptimization) { ttyLocker ttyl; tty->print_cr(" Created vframeArray " INTPTR_FORMAT, array); } #endif // PRODUCT return array; } static void collect_monitors(compiledVFrame* cvf, GrowableArray* objects_to_revoke) { GrowableArray* monitors = cvf->monitors(); for (int i = 0; i < monitors->length(); i++) { MonitorInfo* mon_info = monitors->at(i); if (!mon_info->eliminated() && mon_info->owner() != NULL) { objects_to_revoke->append(Handle(mon_info->owner())); } } } void Deoptimization::revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map) { if (!UseBiasedLocking) { return; } GrowableArray* objects_to_revoke = new GrowableArray(); // Unfortunately we don't have a RegisterMap available in most of // the places we want to call this routine so we need to walk the // stack again to update the register map. if (map == NULL || !map->update_map()) { StackFrameStream sfs(thread, true); bool found = false; while (!found && !sfs.is_done()) { frame* cur = sfs.current(); sfs.next(); found = cur->id() == fr.id(); } assert(found, "frame to be deoptimized not found on target thread's stack"); map = sfs.register_map(); } vframe* vf = vframe::new_vframe(&fr, map, thread); compiledVFrame* cvf = compiledVFrame::cast(vf); // Revoke monitors' biases in all scopes while (!cvf->is_top()) { collect_monitors(cvf, objects_to_revoke); cvf = compiledVFrame::cast(cvf->sender()); } collect_monitors(cvf, objects_to_revoke); if (SafepointSynchronize::is_at_safepoint()) { BiasedLocking::revoke_at_safepoint(objects_to_revoke); } else { BiasedLocking::revoke(objects_to_revoke); } } void Deoptimization::revoke_biases_of_monitors(CodeBlob* cb) { if (!UseBiasedLocking) { return; } assert(SafepointSynchronize::is_at_safepoint(), "must only be called from safepoint"); GrowableArray* objects_to_revoke = new GrowableArray(); for (JavaThread* jt = Threads::first(); jt != NULL ; jt = jt->next()) { if (jt->has_last_Java_frame()) { StackFrameStream sfs(jt, true); while (!sfs.is_done()) { frame* cur = sfs.current(); if (cb->contains(cur->pc())) { vframe* vf = vframe::new_vframe(cur, sfs.register_map(), jt); compiledVFrame* cvf = compiledVFrame::cast(vf); // Revoke monitors' biases in all scopes while (!cvf->is_top()) { collect_monitors(cvf, objects_to_revoke); cvf = compiledVFrame::cast(cvf->sender()); } collect_monitors(cvf, objects_to_revoke); } sfs.next(); } } } BiasedLocking::revoke_at_safepoint(objects_to_revoke); } void Deoptimization::deoptimize_single_frame(JavaThread* thread, frame fr) { assert(fr.can_be_deoptimized(), "checking frame type"); gather_statistics(Reason_constraint, Action_none, Bytecodes::_illegal); EventMark m("Deoptimization (pc=" INTPTR_FORMAT ", sp=" INTPTR_FORMAT ")", fr.pc(), fr.id()); // Patch the nmethod so that when execution returns to it we will // deopt the execution state and return to the interpreter. fr.deoptimize(thread); } void Deoptimization::deoptimize(JavaThread* thread, frame fr, RegisterMap *map) { // Deoptimize only if the frame comes from compile code. // Do not deoptimize the frame which is already patched // during the execution of the loops below. if (!fr.is_compiled_frame() || fr.is_deoptimized_frame()) { return; } ResourceMark rm; DeoptimizationMarker dm; if (UseBiasedLocking) { revoke_biases_of_monitors(thread, fr, map); } deoptimize_single_frame(thread, fr); } void Deoptimization::deoptimize_frame_internal(JavaThread* thread, intptr_t* id) { assert(thread == Thread::current() || SafepointSynchronize::is_at_safepoint(), "can only deoptimize other thread at a safepoint"); // Compute frame and register map based on thread and sp. RegisterMap reg_map(thread, UseBiasedLocking); frame fr = thread->last_frame(); while (fr.id() != id) { fr = fr.sender(®_map); } deoptimize(thread, fr, ®_map); } void Deoptimization::deoptimize_frame(JavaThread* thread, intptr_t* id) { if (thread == Thread::current()) { Deoptimization::deoptimize_frame_internal(thread, id); } else { VM_DeoptimizeFrame deopt(thread, id); VMThread::execute(&deopt); } } // JVMTI PopFrame support JRT_LEAF(void, Deoptimization::popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address)) { thread->popframe_preserve_args(in_ByteSize(bytes_to_save), start_address); } JRT_END #if defined(COMPILER2) || defined(SHARK) void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS) { // in case of an unresolved klass entry, load the class. if (constant_pool->tag_at(index).is_unresolved_klass()) { klassOop tk = constant_pool->klass_at(index, CHECK); return; } if (!constant_pool->tag_at(index).is_symbol()) return; Handle class_loader (THREAD, instanceKlass::cast(constant_pool->pool_holder())->class_loader()); Symbol* symbol = constant_pool->symbol_at(index); // class name? if (symbol->byte_at(0) != '(') { Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain()); SystemDictionary::resolve_or_null(symbol, class_loader, protection_domain, CHECK); return; } // then it must be a signature! ResourceMark rm(THREAD); for (SignatureStream ss(symbol); !ss.is_done(); ss.next()) { if (ss.is_object()) { Symbol* class_name = ss.as_symbol(CHECK); Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain()); SystemDictionary::resolve_or_null(class_name, class_loader, protection_domain, CHECK); } } } void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index) { EXCEPTION_MARK; load_class_by_index(constant_pool, index, THREAD); if (HAS_PENDING_EXCEPTION) { // Exception happened during classloading. We ignore the exception here, since it // is going to be rethrown since the current activation is going to be deoptimzied and // the interpreter will re-execute the bytecode. CLEAR_PENDING_EXCEPTION; } } JRT_ENTRY(void, Deoptimization::uncommon_trap_inner(JavaThread* thread, jint trap_request)) { HandleMark hm; // uncommon_trap() is called at the beginning of the uncommon trap // handler. Note this fact before we start generating temporary frames // that can confuse an asynchronous stack walker. This counter is // decremented at the end of unpack_frames(). thread->inc_in_deopt_handler(); // We need to update the map if we have biased locking. RegisterMap reg_map(thread, UseBiasedLocking); frame stub_frame = thread->last_frame(); frame fr = stub_frame.sender(®_map); // Make sure the calling nmethod is not getting deoptimized and removed // before we are done with it. nmethodLocker nl(fr.pc()); { ResourceMark rm; // Revoke biases of any monitors in the frame to ensure we can migrate them revoke_biases_of_monitors(thread, fr, ®_map); DeoptReason reason = trap_request_reason(trap_request); DeoptAction action = trap_request_action(trap_request); jint unloaded_class_index = trap_request_index(trap_request); // CP idx or -1 Events::log("Uncommon trap occurred @" INTPTR_FORMAT " unloaded_class_index = %d", fr.pc(), (int) trap_request); vframe* vf = vframe::new_vframe(&fr, ®_map, thread); compiledVFrame* cvf = compiledVFrame::cast(vf); nmethod* nm = cvf->code(); ScopeDesc* trap_scope = cvf->scope(); methodHandle trap_method = trap_scope->method(); int trap_bci = trap_scope->bci(); Bytecodes::Code trap_bc = trap_method->java_code_at(trap_bci); // Record this event in the histogram. gather_statistics(reason, action, trap_bc); // Ensure that we can record deopt. history: bool create_if_missing = ProfileTraps; methodDataHandle trap_mdo (THREAD, get_method_data(thread, trap_method, create_if_missing)); // Print a bunch of diagnostics, if requested. if (TraceDeoptimization || LogCompilation) { ResourceMark rm; ttyLocker ttyl; char buf[100]; if (xtty != NULL) { xtty->begin_head("uncommon_trap thread='" UINTX_FORMAT"' %s", os::current_thread_id(), format_trap_request(buf, sizeof(buf), trap_request)); nm->log_identity(xtty); } Symbol* class_name = NULL; bool unresolved = false; if (unloaded_class_index >= 0) { constantPoolHandle constants (THREAD, trap_method->constants()); if (constants->tag_at(unloaded_class_index).is_unresolved_klass()) { class_name = constants->klass_name_at(unloaded_class_index); unresolved = true; if (xtty != NULL) xtty->print(" unresolved='1'"); } else if (constants->tag_at(unloaded_class_index).is_symbol()) { class_name = constants->symbol_at(unloaded_class_index); } if (xtty != NULL) xtty->name(class_name); } if (xtty != NULL && trap_mdo.not_null()) { // Dump the relevant MDO state. // This is the deopt count for the current reason, any previous // reasons or recompiles seen at this point. int dcnt = trap_mdo->trap_count(reason); if (dcnt != 0) xtty->print(" count='%d'", dcnt); ProfileData* pdata = trap_mdo->bci_to_data(trap_bci); int dos = (pdata == NULL)? 0: pdata->trap_state(); if (dos != 0) { xtty->print(" state='%s'", format_trap_state(buf, sizeof(buf), dos)); if (trap_state_is_recompiled(dos)) { int recnt2 = trap_mdo->overflow_recompile_count(); if (recnt2 != 0) xtty->print(" recompiles2='%d'", recnt2); } } } if (xtty != NULL) { xtty->stamp(); xtty->end_head(); } if (TraceDeoptimization) { // make noise on the tty tty->print("Uncommon trap occurred in"); nm->method()->print_short_name(tty); tty->print(" (@" INTPTR_FORMAT ") thread=%d reason=%s action=%s unloaded_class_index=%d", fr.pc(), (int) os::current_thread_id(), trap_reason_name(reason), trap_action_name(action), unloaded_class_index); if (class_name != NULL) { tty->print(unresolved ? " unresolved class: " : " symbol: "); class_name->print_symbol_on(tty); } tty->cr(); } if (xtty != NULL) { // Log the precise location of the trap. for (ScopeDesc* sd = trap_scope; ; sd = sd->sender()) { xtty->begin_elem("jvms bci='%d'", sd->bci()); xtty->method(sd->method()); xtty->end_elem(); if (sd->is_top()) break; } xtty->tail("uncommon_trap"); } } // (End diagnostic printout.) // Load class if necessary if (unloaded_class_index >= 0) { constantPoolHandle constants(THREAD, trap_method->constants()); load_class_by_index(constants, unloaded_class_index); } // Flush the nmethod if necessary and desirable. // // We need to avoid situations where we are re-flushing the nmethod // because of a hot deoptimization site. Repeated flushes at the same // point need to be detected by the compiler and avoided. If the compiler // cannot avoid them (or has a bug and "refuses" to avoid them), this // module must take measures to avoid an infinite cycle of recompilation // and deoptimization. There are several such measures: // // 1. If a recompilation is ordered a second time at some site X // and for the same reason R, the action is adjusted to 'reinterpret', // to give the interpreter time to exercise the method more thoroughly. // If this happens, the method's overflow_recompile_count is incremented. // // 2. If the compiler fails to reduce the deoptimization rate, then // the method's overflow_recompile_count will begin to exceed the set // limit PerBytecodeRecompilationCutoff. If this happens, the action // is adjusted to 'make_not_compilable', and the method is abandoned // to the interpreter. This is a performance hit for hot methods, // but is better than a disastrous infinite cycle of recompilations. // (Actually, only the method containing the site X is abandoned.) // // 3. In parallel with the previous measures, if the total number of // recompilations of a method exceeds the much larger set limit // PerMethodRecompilationCutoff, the method is abandoned. // This should only happen if the method is very large and has // many "lukewarm" deoptimizations. The code which enforces this // limit is elsewhere (class nmethod, class methodOopDesc). // // Note that the per-BCI 'is_recompiled' bit gives the compiler one chance // to recompile at each bytecode independently of the per-BCI cutoff. // // The decision to update code is up to the compiler, and is encoded // in the Action_xxx code. If the compiler requests Action_none // no trap state is changed, no compiled code is changed, and the // computation suffers along in the interpreter. // // The other action codes specify various tactics for decompilation // and recompilation. Action_maybe_recompile is the loosest, and // allows the compiled code to stay around until enough traps are seen, // and until the compiler gets around to recompiling the trapping method. // // The other actions cause immediate removal of the present code. bool update_trap_state = true; bool make_not_entrant = false; bool make_not_compilable = false; bool reprofile = false; switch (action) { case Action_none: // Keep the old code. update_trap_state = false; break; case Action_maybe_recompile: // Do not need to invalidate the present code, but we can // initiate another // Start compiler without (necessarily) invalidating the nmethod. // The system will tolerate the old code, but new code should be // generated when possible. break; case Action_reinterpret: // Go back into the interpreter for a while, and then consider // recompiling form scratch. make_not_entrant = true; // Reset invocation counter for outer most method. // This will allow the interpreter to exercise the bytecodes // for a while before recompiling. // By contrast, Action_make_not_entrant is immediate. // // Note that the compiler will track null_check, null_assert, // range_check, and class_check events and log them as if they // had been traps taken from compiled code. This will update // the MDO trap history so that the next compilation will // properly detect hot trap sites. reprofile = true; break; case Action_make_not_entrant: // Request immediate recompilation, and get rid of the old code. // Make them not entrant, so next time they are called they get // recompiled. Unloaded classes are loaded now so recompile before next // time they are called. Same for uninitialized. The interpreter will // link the missing class, if any. make_not_entrant = true; break; case Action_make_not_compilable: // Give up on compiling this method at all. make_not_entrant = true; make_not_compilable = true; break; default: ShouldNotReachHere(); } // Setting +ProfileTraps fixes the following, on all platforms: // 4852688: ProfileInterpreter is off by default for ia64. The result is // infinite heroic-opt-uncommon-trap/deopt/recompile cycles, since the // recompile relies on a methodDataOop to record heroic opt failures. // Whether the interpreter is producing MDO data or not, we also need // to use the MDO to detect hot deoptimization points and control // aggressive optimization. bool inc_recompile_count = false; ProfileData* pdata = NULL; if (ProfileTraps && update_trap_state && trap_mdo.not_null()) { assert(trap_mdo() == get_method_data(thread, trap_method, false), "sanity"); uint this_trap_count = 0; bool maybe_prior_trap = false; bool maybe_prior_recompile = false; pdata = query_update_method_data(trap_mdo, trap_bci, reason, //outputs: this_trap_count, maybe_prior_trap, maybe_prior_recompile); // Because the interpreter also counts null, div0, range, and class // checks, these traps from compiled code are double-counted. // This is harmless; it just means that the PerXTrapLimit values // are in effect a little smaller than they look. DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason); if (per_bc_reason != Reason_none) { // Now take action based on the partially known per-BCI history. if (maybe_prior_trap && this_trap_count >= (uint)PerBytecodeTrapLimit) { // If there are too many traps at this BCI, force a recompile. // This will allow the compiler to see the limit overflow, and // take corrective action, if possible. The compiler generally // does not use the exact PerBytecodeTrapLimit value, but instead // changes its tactics if it sees any traps at all. This provides // a little hysteresis, delaying a recompile until a trap happens // several times. // // Actually, since there is only one bit of counter per BCI, // the possible per-BCI counts are {0,1,(per-method count)}. // This produces accurate results if in fact there is only // one hot trap site, but begins to get fuzzy if there are // many sites. For example, if there are ten sites each // trapping two or more times, they each get the blame for // all of their traps. make_not_entrant = true; if (per_bc_reason == Reason_unhandled) { make_not_compilable = true; } } // Detect repeated recompilation at the same BCI, and enforce a limit. if (make_not_entrant && maybe_prior_recompile) { // More than one recompile at this point. inc_recompile_count = maybe_prior_trap; } } else { // For reasons which are not recorded per-bytecode, we simply // force recompiles unconditionally. // (Note that PerMethodRecompilationCutoff is enforced elsewhere.) make_not_entrant = true; } // Go back to the compiler if there are too many traps in this method. if (this_trap_count >= (uint)PerMethodTrapLimit) { // If there are too many traps in this method, force a recompile. // This will allow the compiler to see the limit overflow, and // take corrective action, if possible. // (This condition is an unlikely backstop only, because the // PerBytecodeTrapLimit is more likely to take effect first, // if it is applicable.) make_not_entrant = true; } // Here's more hysteresis: If there has been a recompile at // this trap point already, run the method in the interpreter // for a while to exercise it more thoroughly. if (make_not_entrant && maybe_prior_recompile && maybe_prior_trap) { reprofile = true; } } // Take requested actions on the method: // Recompile if (make_not_entrant) { if (!nm->make_not_entrant()) { return; // the call did not change nmethod's state } if (pdata != NULL) { // Record the recompilation event, if any. int tstate0 = pdata->trap_state(); int tstate1 = trap_state_set_recompiled(tstate0, true); if (tstate1 != tstate0) pdata->set_trap_state(tstate1); } } if (inc_recompile_count) { trap_mdo->inc_overflow_recompile_count(); if ((uint)trap_mdo->overflow_recompile_count() > (uint)PerBytecodeRecompilationCutoff) { // Give up on the method containing the bad BCI. if (trap_method() == nm->method()) { make_not_compilable = true; } else { trap_method->set_not_compilable(CompLevel_full_optimization); // But give grace to the enclosing nm->method(). } } } // Reprofile if (reprofile) { CompilationPolicy::policy()->reprofile(trap_scope, nm->is_osr_method()); } // Give up compiling if (make_not_compilable && !nm->method()->is_not_compilable(CompLevel_full_optimization)) { assert(make_not_entrant, "consistent"); nm->method()->set_not_compilable(CompLevel_full_optimization); } } // Free marked resources } JRT_END methodDataOop Deoptimization::get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing) { Thread* THREAD = thread; methodDataOop mdo = m()->method_data(); if (mdo == NULL && create_if_missing && !HAS_PENDING_EXCEPTION) { // Build an MDO. Ignore errors like OutOfMemory; // that simply means we won't have an MDO to update. methodOopDesc::build_interpreter_method_data(m, THREAD); if (HAS_PENDING_EXCEPTION) { assert((PENDING_EXCEPTION->is_a(SystemDictionary::OutOfMemoryError_klass())), "we expect only an OOM error here"); CLEAR_PENDING_EXCEPTION; } mdo = m()->method_data(); } return mdo; } ProfileData* Deoptimization::query_update_method_data(methodDataHandle trap_mdo, int trap_bci, Deoptimization::DeoptReason reason, //outputs: uint& ret_this_trap_count, bool& ret_maybe_prior_trap, bool& ret_maybe_prior_recompile) { uint prior_trap_count = trap_mdo->trap_count(reason); uint this_trap_count = trap_mdo->inc_trap_count(reason); // If the runtime cannot find a place to store trap history, // it is estimated based on the general condition of the method. // If the method has ever been recompiled, or has ever incurred // a trap with the present reason , then this BCI is assumed // (pessimistically) to be the culprit. bool maybe_prior_trap = (prior_trap_count != 0); bool maybe_prior_recompile = (trap_mdo->decompile_count() != 0); ProfileData* pdata = NULL; // For reasons which are recorded per bytecode, we check per-BCI data. DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason); if (per_bc_reason != Reason_none) { // Find the profile data for this BCI. If there isn't one, // try to allocate one from the MDO's set of spares. // This will let us detect a repeated trap at this point. pdata = trap_mdo->allocate_bci_to_data(trap_bci); if (pdata != NULL) { // Query the trap state of this profile datum. int tstate0 = pdata->trap_state(); if (!trap_state_has_reason(tstate0, per_bc_reason)) maybe_prior_trap = false; if (!trap_state_is_recompiled(tstate0)) maybe_prior_recompile = false; // Update the trap state of this profile datum. int tstate1 = tstate0; // Record the reason. tstate1 = trap_state_add_reason(tstate1, per_bc_reason); // Store the updated state on the MDO, for next time. if (tstate1 != tstate0) pdata->set_trap_state(tstate1); } else { if (LogCompilation && xtty != NULL) { ttyLocker ttyl; // Missing MDP? Leave a small complaint in the log. xtty->elem("missing_mdp bci='%d'", trap_bci); } } } // Return results: ret_this_trap_count = this_trap_count; ret_maybe_prior_trap = maybe_prior_trap; ret_maybe_prior_recompile = maybe_prior_recompile; return pdata; } void Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) { ResourceMark rm; // Ignored outputs: uint ignore_this_trap_count; bool ignore_maybe_prior_trap; bool ignore_maybe_prior_recompile; query_update_method_data(trap_mdo, trap_bci, (DeoptReason)reason, ignore_this_trap_count, ignore_maybe_prior_trap, ignore_maybe_prior_recompile); } Deoptimization::UnrollBlock* Deoptimization::uncommon_trap(JavaThread* thread, jint trap_request) { // Still in Java no safepoints { // This enters VM and may safepoint uncommon_trap_inner(thread, trap_request); } return fetch_unroll_info_helper(thread); } // Local derived constants. // Further breakdown of DataLayout::trap_state, as promised by DataLayout. const int DS_REASON_MASK = DataLayout::trap_mask >> 1; const int DS_RECOMPILE_BIT = DataLayout::trap_mask - DS_REASON_MASK; //---------------------------trap_state_reason--------------------------------- Deoptimization::DeoptReason Deoptimization::trap_state_reason(int trap_state) { // This assert provides the link between the width of DataLayout::trap_bits // and the encoding of "recorded" reasons. It ensures there are enough // bits to store all needed reasons in the per-BCI MDO profile. assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits"); int recompile_bit = (trap_state & DS_RECOMPILE_BIT); trap_state -= recompile_bit; if (trap_state == DS_REASON_MASK) { return Reason_many; } else { assert((int)Reason_none == 0, "state=0 => Reason_none"); return (DeoptReason)trap_state; } } //-------------------------trap_state_has_reason------------------------------- int Deoptimization::trap_state_has_reason(int trap_state, int reason) { assert(reason_is_recorded_per_bytecode((DeoptReason)reason), "valid reason"); assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits"); int recompile_bit = (trap_state & DS_RECOMPILE_BIT); trap_state -= recompile_bit; if (trap_state == DS_REASON_MASK) { return -1; // true, unspecifically (bottom of state lattice) } else if (trap_state == reason) { return 1; // true, definitely } else if (trap_state == 0) { return 0; // false, definitely (top of state lattice) } else { return 0; // false, definitely } } //-------------------------trap_state_add_reason------------------------------- int Deoptimization::trap_state_add_reason(int trap_state, int reason) { assert(reason_is_recorded_per_bytecode((DeoptReason)reason) || reason == Reason_many, "valid reason"); int recompile_bit = (trap_state & DS_RECOMPILE_BIT); trap_state -= recompile_bit; if (trap_state == DS_REASON_MASK) { return trap_state + recompile_bit; // already at state lattice bottom } else if (trap_state == reason) { return trap_state + recompile_bit; // the condition is already true } else if (trap_state == 0) { return reason + recompile_bit; // no condition has yet been true } else { return DS_REASON_MASK + recompile_bit; // fall to state lattice bottom } } //-----------------------trap_state_is_recompiled------------------------------ bool Deoptimization::trap_state_is_recompiled(int trap_state) { return (trap_state & DS_RECOMPILE_BIT) != 0; } //-----------------------trap_state_set_recompiled----------------------------- int Deoptimization::trap_state_set_recompiled(int trap_state, bool z) { if (z) return trap_state | DS_RECOMPILE_BIT; else return trap_state & ~DS_RECOMPILE_BIT; } //---------------------------format_trap_state--------------------------------- // This is used for debugging and diagnostics, including hotspot.log output. const char* Deoptimization::format_trap_state(char* buf, size_t buflen, int trap_state) { DeoptReason reason = trap_state_reason(trap_state); bool recomp_flag = trap_state_is_recompiled(trap_state); // Re-encode the state from its decoded components. int decoded_state = 0; if (reason_is_recorded_per_bytecode(reason) || reason == Reason_many) decoded_state = trap_state_add_reason(decoded_state, reason); if (recomp_flag) decoded_state = trap_state_set_recompiled(decoded_state, recomp_flag); // If the state re-encodes properly, format it symbolically. // Because this routine is used for debugging and diagnostics, // be robust even if the state is a strange value. size_t len; if (decoded_state != trap_state) { // Random buggy state that doesn't decode?? len = jio_snprintf(buf, buflen, "#%d", trap_state); } else { len = jio_snprintf(buf, buflen, "%s%s", trap_reason_name(reason), recomp_flag ? " recompiled" : ""); } if (len >= buflen) buf[buflen-1] = '\0'; return buf; } //--------------------------------statics-------------------------------------- Deoptimization::DeoptAction Deoptimization::_unloaded_action = Deoptimization::Action_reinterpret; const char* Deoptimization::_trap_reason_name[Reason_LIMIT] = { // Note: Keep this in sync. with enum DeoptReason. "none", "null_check", "null_assert", "range_check", "class_check", "array_check", "intrinsic", "bimorphic", "unloaded", "uninitialized", "unreached", "unhandled", "constraint", "div0_check", "age", "predicate", "loop_limit_check" }; const char* Deoptimization::_trap_action_name[Action_LIMIT] = { // Note: Keep this in sync. with enum DeoptAction. "none", "maybe_recompile", "reinterpret", "make_not_entrant", "make_not_compilable" }; const char* Deoptimization::trap_reason_name(int reason) { if (reason == Reason_many) return "many"; if ((uint)reason < Reason_LIMIT) return _trap_reason_name[reason]; static char buf[20]; sprintf(buf, "reason%d", reason); return buf; } const char* Deoptimization::trap_action_name(int action) { if ((uint)action < Action_LIMIT) return _trap_action_name[action]; static char buf[20]; sprintf(buf, "action%d", action); return buf; } // This is used for debugging and diagnostics, including hotspot.log output. const char* Deoptimization::format_trap_request(char* buf, size_t buflen, int trap_request) { jint unloaded_class_index = trap_request_index(trap_request); const char* reason = trap_reason_name(trap_request_reason(trap_request)); const char* action = trap_action_name(trap_request_action(trap_request)); size_t len; if (unloaded_class_index < 0) { len = jio_snprintf(buf, buflen, "reason='%s' action='%s'", reason, action); } else { len = jio_snprintf(buf, buflen, "reason='%s' action='%s' index='%d'", reason, action, unloaded_class_index); } if (len >= buflen) buf[buflen-1] = '\0'; return buf; } juint Deoptimization::_deoptimization_hist [Deoptimization::Reason_LIMIT] [1 + Deoptimization::Action_LIMIT] [Deoptimization::BC_CASE_LIMIT] = {0}; enum { LSB_BITS = 8, LSB_MASK = right_n_bits(LSB_BITS) }; void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action, Bytecodes::Code bc) { assert(reason >= 0 && reason < Reason_LIMIT, "oob"); assert(action >= 0 && action < Action_LIMIT, "oob"); _deoptimization_hist[Reason_none][0][0] += 1; // total _deoptimization_hist[reason][0][0] += 1; // per-reason total juint* cases = _deoptimization_hist[reason][1+action]; juint* bc_counter_addr = NULL; juint bc_counter = 0; // Look for an unused counter, or an exact match to this BC. if (bc != Bytecodes::_illegal) { for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) { juint* counter_addr = &cases[bc_case]; juint counter = *counter_addr; if ((counter == 0 && bc_counter_addr == NULL) || (Bytecodes::Code)(counter & LSB_MASK) == bc) { // this counter is either free or is already devoted to this BC bc_counter_addr = counter_addr; bc_counter = counter | bc; } } } if (bc_counter_addr == NULL) { // Overflow, or no given bytecode. bc_counter_addr = &cases[BC_CASE_LIMIT-1]; bc_counter = (*bc_counter_addr & ~LSB_MASK); // clear LSB } *bc_counter_addr = bc_counter + (1 << LSB_BITS); } jint Deoptimization::total_deoptimization_count() { return _deoptimization_hist[Reason_none][0][0]; } jint Deoptimization::deoptimization_count(DeoptReason reason) { assert(reason >= 0 && reason < Reason_LIMIT, "oob"); return _deoptimization_hist[reason][0][0]; } void Deoptimization::print_statistics() { juint total = total_deoptimization_count(); juint account = total; if (total != 0) { ttyLocker ttyl; if (xtty != NULL) xtty->head("statistics type='deoptimization'"); tty->print_cr("Deoptimization traps recorded:"); #define PRINT_STAT_LINE(name, r) \ tty->print_cr(" %4d (%4.1f%%) %s", (int)(r), ((r) * 100.0) / total, name); PRINT_STAT_LINE("total", total); // For each non-zero entry in the histogram, print the reason, // the action, and (if specifically known) the type of bytecode. for (int reason = 0; reason < Reason_LIMIT; reason++) { for (int action = 0; action < Action_LIMIT; action++) { juint* cases = _deoptimization_hist[reason][1+action]; for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) { juint counter = cases[bc_case]; if (counter != 0) { char name[1*K]; Bytecodes::Code bc = (Bytecodes::Code)(counter & LSB_MASK); if (bc_case == BC_CASE_LIMIT && (int)bc == 0) bc = Bytecodes::_illegal; sprintf(name, "%s/%s/%s", trap_reason_name(reason), trap_action_name(action), Bytecodes::is_defined(bc)? Bytecodes::name(bc): "other"); juint r = counter >> LSB_BITS; tty->print_cr(" %40s: " UINT32_FORMAT " (%.1f%%)", name, r, (r * 100.0) / total); account -= r; } } } } if (account != 0) { PRINT_STAT_LINE("unaccounted", account); } #undef PRINT_STAT_LINE if (xtty != NULL) xtty->tail("statistics"); } } #else // COMPILER2 || SHARK // Stubs for C1 only system. bool Deoptimization::trap_state_is_recompiled(int trap_state) { return false; } const char* Deoptimization::trap_reason_name(int reason) { return "unknown"; } void Deoptimization::print_statistics() { // no output } void Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) { // no udpate } int Deoptimization::trap_state_has_reason(int trap_state, int reason) { return 0; } void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action, Bytecodes::Code bc) { // no update } const char* Deoptimization::format_trap_state(char* buf, size_t buflen, int trap_state) { jio_snprintf(buf, buflen, "#%d", trap_state); return buf; } #endif // COMPILER2 || SHARK