/* * Copyright (c) 2009, 2015, 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 "compiler/compileLog.hpp" #include "opto/addnode.hpp" #include "opto/callGenerator.hpp" #include "opto/callnode.hpp" #include "opto/divnode.hpp" #include "opto/graphKit.hpp" #include "opto/idealKit.hpp" #include "opto/rootnode.hpp" #include "opto/runtime.hpp" #include "opto/stringopts.hpp" #include "opto/subnode.hpp" #include "runtime/sharedRuntime.hpp" #define __ kit. class StringConcat : public ResourceObj { private: PhaseStringOpts* _stringopts; Node* _string_alloc; AllocateNode* _begin; // The allocation the begins the pattern CallStaticJavaNode* _end; // The final call of the pattern. Will either be // SB.toString or or String.(SB.toString) bool _multiple; // indicates this is a fusion of two or more // separate StringBuilders Node* _arguments; // The list of arguments to be concatenated GrowableArray _mode; // into a String along with a mode flag // indicating how to treat the value. Node_List _constructors; // List of constructors (many in case of stacked concat) Node_List _control; // List of control nodes that will be deleted Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten // to restart at the initial JVMState. public: // Mode for converting arguments to Strings enum { StringMode, IntMode, CharMode, StringNullCheckMode }; StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end): _end(end), _begin(NULL), _multiple(false), _string_alloc(NULL), _stringopts(stringopts) { _arguments = new Node(1); _arguments->del_req(0); } bool validate_mem_flow(); bool validate_control_flow(); void merge_add() { #if 0 // XXX This is place holder code for reusing an existing String // allocation but the logic for checking the state safety is // probably inadequate at the moment. CallProjections endprojs; sc->end()->extract_projections(&endprojs, false); if (endprojs.resproj != NULL) { for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) { CallStaticJavaNode *use = i.get()->isa_CallStaticJava(); if (use != NULL && use->method() != NULL && use->method()->intrinsic_id() == vmIntrinsics::_String_String && use->in(TypeFunc::Parms + 1) == endprojs.resproj) { // Found useless new String(sb.toString()) so reuse the newly allocated String // when creating the result instead of allocating a new one. sc->set_string_alloc(use->in(TypeFunc::Parms)); sc->set_end(use); } } } #endif } StringConcat* merge(StringConcat* other, Node* arg); void set_allocation(AllocateNode* alloc) { _begin = alloc; } void append(Node* value, int mode) { _arguments->add_req(value); _mode.append(mode); } void push(Node* value, int mode) { _arguments->ins_req(0, value); _mode.insert_before(0, mode); } void push_string(Node* value) { push(value, StringMode); } void push_string_null_check(Node* value) { push(value, StringNullCheckMode); } void push_int(Node* value) { push(value, IntMode); } void push_char(Node* value) { push(value, CharMode); } static bool is_SB_toString(Node* call) { if (call->is_CallStaticJava()) { CallStaticJavaNode* csj = call->as_CallStaticJava(); ciMethod* m = csj->method(); if (m != NULL && (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString || m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) { return true; } } return false; } static Node* skip_string_null_check(Node* value) { // Look for a diamond shaped Null check of toString() result // (could be code from String.valueOf()): // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL if (value->is_Phi()) { int true_path = value->as_Phi()->is_diamond_phi(); if (true_path != 0) { // phi->region->if_proj->ifnode->bool BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool(); Node* cmp = b->in(1); Node* v1 = cmp->in(1); Node* v2 = cmp->in(2); // Null check of the return of toString which can simply be skipped. if (b->_test._test == BoolTest::ne && v2->bottom_type() == TypePtr::NULL_PTR && value->in(true_path)->Opcode() == Op_CastPP && value->in(true_path)->in(1) == v1 && v1->is_Proj() && is_SB_toString(v1->in(0))) { return v1; } } } return value; } Node* argument(int i) { return _arguments->in(i); } Node* argument_uncast(int i) { Node* arg = argument(i); int amode = mode(i); if (amode == StringConcat::StringMode || amode == StringConcat::StringNullCheckMode) { arg = skip_string_null_check(arg); } return arg; } void set_argument(int i, Node* value) { _arguments->set_req(i, value); } int num_arguments() { return _mode.length(); } int mode(int i) { return _mode.at(i); } void add_control(Node* ctrl) { assert(!_control.contains(ctrl), "only push once"); _control.push(ctrl); } void add_constructor(Node* init) { assert(!_constructors.contains(init), "only push once"); _constructors.push(init); } CallStaticJavaNode* end() { return _end; } AllocateNode* begin() { return _begin; } Node* string_alloc() { return _string_alloc; } void eliminate_unneeded_control(); void eliminate_initialize(InitializeNode* init); void eliminate_call(CallNode* call); void maybe_log_transform() { CompileLog* log = _stringopts->C->log(); if (log != NULL) { log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'", num_arguments(), _string_alloc != NULL, _multiple); JVMState* p = _begin->jvms(); while (p != NULL) { log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method())); p = p->caller(); } log->tail("replace_string_concat"); } } void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) { for (uint u = 0; u < _uncommon_traps.size(); u++) { Node* uct = _uncommon_traps.at(u); // Build a new call using the jvms state of the allocate address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point(); const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type(); const TypePtr* no_memory_effects = NULL; Compile* C = _stringopts->C; CallStaticJavaNode* call = new CallStaticJavaNode(call_type, call_addr, "uncommon_trap", jvms->bci(), no_memory_effects); for (int e = 0; e < TypeFunc::Parms; e++) { call->init_req(e, uct->in(e)); } // Set the trap request to record intrinsic failure if this trap // is taken too many times. Ideally we would handle then traps by // doing the original bookkeeping in the MDO so that if it caused // the code to be thrown out we could still recompile and use the // optimization. Failing the uncommon traps doesn't really mean // that the optimization is a bad idea but there's no other way to // do the MDO updates currently. int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic, Deoptimization::Action_make_not_entrant); call->init_req(TypeFunc::Parms, __ intcon(trap_request)); kit.add_safepoint_edges(call); _stringopts->gvn()->transform(call); C->gvn_replace_by(uct, call); uct->disconnect_inputs(NULL, C); } } void cleanup() { // disconnect the hook node _arguments->disconnect_inputs(NULL, _stringopts->C); } }; void StringConcat::eliminate_unneeded_control() { for (uint i = 0; i < _control.size(); i++) { Node* n = _control.at(i); if (n->is_Allocate()) { eliminate_initialize(n->as_Allocate()->initialization()); } if (n->is_Call()) { if (n != _end) { eliminate_call(n->as_Call()); } } else if (n->is_IfTrue()) { Compile* C = _stringopts->C; C->gvn_replace_by(n, n->in(0)->in(0)); // get rid of the other projection C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top()); } } } StringConcat* StringConcat::merge(StringConcat* other, Node* arg) { StringConcat* result = new StringConcat(_stringopts, _end); for (uint x = 0; x < _control.size(); x++) { Node* n = _control.at(x); if (n->is_Call()) { result->_control.push(n); } } for (uint x = 0; x < other->_control.size(); x++) { Node* n = other->_control.at(x); if (n->is_Call()) { result->_control.push(n); } } assert(result->_control.contains(other->_end), "what?"); assert(result->_control.contains(_begin), "what?"); for (int x = 0; x < num_arguments(); x++) { Node* argx = argument_uncast(x); if (argx == arg) { // replace the toString result with the all the arguments that // made up the other StringConcat for (int y = 0; y < other->num_arguments(); y++) { result->append(other->argument(y), other->mode(y)); } } else { result->append(argx, mode(x)); } } result->set_allocation(other->_begin); for (uint i = 0; i < _constructors.size(); i++) { result->add_constructor(_constructors.at(i)); } for (uint i = 0; i < other->_constructors.size(); i++) { result->add_constructor(other->_constructors.at(i)); } result->_multiple = true; return result; } void StringConcat::eliminate_call(CallNode* call) { Compile* C = _stringopts->C; CallProjections projs; call->extract_projections(&projs, false); if (projs.fallthrough_catchproj != NULL) { C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control)); } if (projs.fallthrough_memproj != NULL) { C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory)); } if (projs.catchall_memproj != NULL) { C->gvn_replace_by(projs.catchall_memproj, C->top()); } if (projs.fallthrough_ioproj != NULL) { C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O)); } if (projs.catchall_ioproj != NULL) { C->gvn_replace_by(projs.catchall_ioproj, C->top()); } if (projs.catchall_catchproj != NULL) { // EA can't cope with the partially collapsed graph this // creates so put it on the worklist to be collapsed later. for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) { Node *use = i.get(); int opc = use->Opcode(); if (opc == Op_CreateEx || opc == Op_Region) { _stringopts->record_dead_node(use); } } C->gvn_replace_by(projs.catchall_catchproj, C->top()); } if (projs.resproj != NULL) { C->gvn_replace_by(projs.resproj, C->top()); } C->gvn_replace_by(call, C->top()); } void StringConcat::eliminate_initialize(InitializeNode* init) { Compile* C = _stringopts->C; // Eliminate Initialize node. assert(init->outcnt() <= 2, "only a control and memory projection expected"); assert(init->req() <= InitializeNode::RawStores, "no pending inits"); Node *ctrl_proj = init->proj_out(TypeFunc::Control); if (ctrl_proj != NULL) { C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control)); } Node *mem_proj = init->proj_out(TypeFunc::Memory); if (mem_proj != NULL) { Node *mem = init->in(TypeFunc::Memory); C->gvn_replace_by(mem_proj, mem); } C->gvn_replace_by(init, C->top()); init->disconnect_inputs(NULL, C); } Node_List PhaseStringOpts::collect_toString_calls() { Node_List string_calls; Node_List worklist; _visited.Clear(); // Prime the worklist for (uint i = 1; i < C->root()->len(); i++) { Node* n = C->root()->in(i); if (n != NULL && !_visited.test_set(n->_idx)) { worklist.push(n); } } while (worklist.size() > 0) { Node* ctrl = worklist.pop(); if (StringConcat::is_SB_toString(ctrl)) { CallStaticJavaNode* csj = ctrl->as_CallStaticJava(); string_calls.push(csj); } if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) { worklist.push(ctrl->in(0)); } if (ctrl->is_Region()) { for (uint i = 1; i < ctrl->len(); i++) { if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) { worklist.push(ctrl->in(i)); } } } } return string_calls; } StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) { ciMethod* m = call->method(); ciSymbol* string_sig; ciSymbol* int_sig; ciSymbol* char_sig; if (m->holder() == C->env()->StringBuilder_klass()) { string_sig = ciSymbol::String_StringBuilder_signature(); int_sig = ciSymbol::int_StringBuilder_signature(); char_sig = ciSymbol::char_StringBuilder_signature(); } else if (m->holder() == C->env()->StringBuffer_klass()) { string_sig = ciSymbol::String_StringBuffer_signature(); int_sig = ciSymbol::int_StringBuffer_signature(); char_sig = ciSymbol::char_StringBuffer_signature(); } else { return NULL; } #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("considering toString call in "); call->jvms()->dump_spec(tty); tty->cr(); } #endif StringConcat* sc = new StringConcat(this, call); AllocateNode* alloc = NULL; InitializeNode* init = NULL; // possible opportunity for StringBuilder fusion CallStaticJavaNode* cnode = call; while (cnode) { Node* recv = cnode->in(TypeFunc::Parms)->uncast(); if (recv->is_Proj()) { recv = recv->in(0); } cnode = recv->isa_CallStaticJava(); if (cnode == NULL) { alloc = recv->isa_Allocate(); if (alloc == NULL) { break; } // Find the constructor call Node* result = alloc->result_cast(); if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) { // strange looking allocation #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("giving up because allocation looks strange "); alloc->jvms()->dump_spec(tty); tty->cr(); } #endif break; } Node* constructor = NULL; for (SimpleDUIterator i(result); i.has_next(); i.next()) { CallStaticJavaNode *use = i.get()->isa_CallStaticJava(); if (use != NULL && use->method() != NULL && !use->method()->is_static() && use->method()->name() == ciSymbol::object_initializer_name() && use->method()->holder() == m->holder()) { // Matched the constructor. ciSymbol* sig = use->method()->signature()->as_symbol(); if (sig == ciSymbol::void_method_signature() || sig == ciSymbol::int_void_signature() || sig == ciSymbol::string_void_signature()) { if (sig == ciSymbol::string_void_signature()) { // StringBuilder(String) so pick this up as the first argument assert(use->in(TypeFunc::Parms + 1) != NULL, "what?"); const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1)); if (type == TypePtr::NULL_PTR) { // StringBuilder(null) throws exception. #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("giving up because StringBuilder(null) throws exception"); alloc->jvms()->dump_spec(tty); tty->cr(); } #endif return NULL; } // StringBuilder(str) argument needs null check. sc->push_string_null_check(use->in(TypeFunc::Parms + 1)); } // The int variant takes an initial size for the backing // array so just treat it like the void version. constructor = use; } else { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("unexpected constructor signature: %s", sig->as_utf8()); } #endif } break; } } if (constructor == NULL) { // couldn't find constructor #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("giving up because couldn't find constructor "); alloc->jvms()->dump_spec(tty); tty->cr(); } #endif break; } // Walked all the way back and found the constructor call so see // if this call converted into a direct string concatenation. sc->add_control(call); sc->add_control(constructor); sc->add_control(alloc); sc->set_allocation(alloc); sc->add_constructor(constructor); if (sc->validate_control_flow() && sc->validate_mem_flow()) { return sc; } else { return NULL; } } else if (cnode->method() == NULL) { break; } else if (!cnode->method()->is_static() && cnode->method()->holder() == m->holder() && cnode->method()->name() == ciSymbol::append_name() && (cnode->method()->signature()->as_symbol() == string_sig || cnode->method()->signature()->as_symbol() == char_sig || cnode->method()->signature()->as_symbol() == int_sig)) { sc->add_control(cnode); Node* arg = cnode->in(TypeFunc::Parms + 1); if (cnode->method()->signature()->as_symbol() == int_sig) { sc->push_int(arg); } else if (cnode->method()->signature()->as_symbol() == char_sig) { sc->push_char(arg); } else { if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) { CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava(); if (csj->method() != NULL && csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString && arg->outcnt() == 1) { // _control is the list of StringBuilder calls nodes which // will be replaced by new String code after this optimization. // Integer::toString() call is not part of StringBuilder calls // chain. It could be eliminated only if its result is used // only by this SB calls chain. // Another limitation: it should be used only once because // it is unknown that it is used only by this SB calls chain // until all related SB calls nodes are collected. assert(arg->unique_out() == cnode, "sanity"); sc->add_control(csj); sc->push_int(csj->in(TypeFunc::Parms)); continue; } } sc->push_string(arg); } continue; } else { // some unhandled signature #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("giving up because encountered unexpected signature "); cnode->tf()->dump(); tty->cr(); cnode->in(TypeFunc::Parms + 1)->dump(); } #endif break; } } return NULL; } PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*): Phase(StringOpts), _gvn(gvn), _visited(Thread::current()->resource_area()) { assert(OptimizeStringConcat, "shouldn't be here"); size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"), ciSymbol::make("[I"), true); if (size_table_field == NULL) { // Something wrong so give up. assert(false, "why can't we find Integer.sizeTable?"); return; } // Collect the types needed to talk about the various slices of memory char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS); // For each locally allocated StringBuffer see if the usages can be // collapsed into a single String construction. // Run through the list of allocation looking for SB.toString to see // if it's possible to fuse the usage of the SB into a single String // construction. GrowableArray concats; Node_List toStrings = collect_toString_calls(); while (toStrings.size() > 0) { StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava()); if (sc != NULL) { concats.push(sc); } } // try to coalesce separate concats restart: for (int c = 0; c < concats.length(); c++) { StringConcat* sc = concats.at(c); for (int i = 0; i < sc->num_arguments(); i++) { Node* arg = sc->argument_uncast(i); if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) { CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava(); for (int o = 0; o < concats.length(); o++) { if (c == o) continue; StringConcat* other = concats.at(o); if (other->end() == csj) { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print_cr("considering stacked concats"); } #endif StringConcat* merged = sc->merge(other, arg); if (merged->validate_control_flow() && merged->validate_mem_flow()) { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print_cr("stacking would succeed"); } #endif if (c < o) { concats.remove_at(o); concats.at_put(c, merged); } else { concats.remove_at(c); concats.at_put(o, merged); } goto restart; } else { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print_cr("stacking would fail"); } #endif } } } } } } for (int c = 0; c < concats.length(); c++) { StringConcat* sc = concats.at(c); replace_string_concat(sc); } remove_dead_nodes(); } void PhaseStringOpts::record_dead_node(Node* dead) { dead_worklist.push(dead); } void PhaseStringOpts::remove_dead_nodes() { // Delete any dead nodes to make things clean enough that escape // analysis doesn't get unhappy. while (dead_worklist.size() > 0) { Node* use = dead_worklist.pop(); int opc = use->Opcode(); switch (opc) { case Op_Region: { uint i = 1; for (i = 1; i < use->req(); i++) { if (use->in(i) != C->top()) { break; } } if (i >= use->req()) { for (SimpleDUIterator i(use); i.has_next(); i.next()) { Node* m = i.get(); if (m->is_Phi()) { dead_worklist.push(m); } } C->gvn_replace_by(use, C->top()); } break; } case Op_AddP: case Op_CreateEx: { // Recurisvely clean up references to CreateEx so EA doesn't // get unhappy about the partially collapsed graph. for (SimpleDUIterator i(use); i.has_next(); i.next()) { Node* m = i.get(); if (m->is_AddP()) { dead_worklist.push(m); } } C->gvn_replace_by(use, C->top()); break; } case Op_Phi: if (use->in(0) == C->top()) { C->gvn_replace_by(use, C->top()); } break; } } } bool StringConcat::validate_mem_flow() { Compile* C = _stringopts->C; for (uint i = 0; i < _control.size(); i++) { #ifndef PRODUCT Node_List path; #endif Node* curr = _control.at(i); if (curr->is_Call() && curr != _begin) { // For all calls except the first allocation // Now here's the main invariant in our case: // For memory between the constructor, and appends, and toString we should only see bottom memory, // produced by the previous call we know about. if (!_constructors.contains(curr)) { NOT_PRODUCT(path.push(curr);) Node* mem = curr->in(TypeFunc::Memory); assert(mem != NULL, "calls should have memory edge"); assert(!mem->is_Phi(), "should be handled by control flow validation"); NOT_PRODUCT(path.push(mem);) while (mem->is_MergeMem()) { for (uint i = 1; i < mem->req(); i++) { if (i != Compile::AliasIdxBot && mem->in(i) != C->top()) { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("fusion has incorrect memory flow (side effects) for "); _begin->jvms()->dump_spec(tty); tty->cr(); path.dump(); } #endif return false; } } // skip through a potential MergeMem chain, linked through Bot mem = mem->in(Compile::AliasIdxBot); NOT_PRODUCT(path.push(mem);) } // now let it fall through, and see if we have a projection if (mem->is_Proj()) { // Should point to a previous known call Node *prev = mem->in(0); NOT_PRODUCT(path.push(prev);) if (!prev->is_Call() || !_control.contains(prev)) { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("fusion has incorrect memory flow (unknown call) for "); _begin->jvms()->dump_spec(tty); tty->cr(); path.dump(); } #endif return false; } } else { assert(mem->is_Store() || mem->is_LoadStore(), err_msg_res("unexpected node type: %s", mem->Name())); #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("fusion has incorrect memory flow (unexpected source) for "); _begin->jvms()->dump_spec(tty); tty->cr(); path.dump(); } #endif return false; } } else { // For memory that feeds into constructors it's more complicated. // However the advantage is that any side effect that happens between the Allocate/Initialize and // the constructor will have to be control-dependent on Initialize. // So we actually don't have to do anything, since it's going to be caught by the control flow // analysis. #ifdef ASSERT // Do a quick verification of the control pattern between the constructor and the initialize node assert(curr->is_Call(), "constructor should be a call"); // Go up the control starting from the constructor call Node* ctrl = curr->in(0); IfNode* iff = NULL; RegionNode* copy = NULL; while (true) { // skip known check patterns if (ctrl->is_Region()) { if (ctrl->as_Region()->is_copy()) { copy = ctrl->as_Region(); ctrl = copy->is_copy(); } else { // a cast assert(ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(1)->is_Proj() && ctrl->in(2) != NULL && ctrl->in(2)->is_Proj() && ctrl->in(1)->in(0) == ctrl->in(2)->in(0) && ctrl->in(1)->in(0) != NULL && ctrl->in(1)->in(0)->is_If(), "must be a simple diamond"); Node* true_proj = ctrl->in(1)->is_IfTrue() ? ctrl->in(1) : ctrl->in(2); for (SimpleDUIterator i(true_proj); i.has_next(); i.next()) { Node* use = i.get(); assert(use == ctrl || use->is_ConstraintCast(), err_msg_res("unexpected user: %s", use->Name())); } iff = ctrl->in(1)->in(0)->as_If(); ctrl = iff->in(0); } } else if (ctrl->is_IfTrue()) { // null checks, class checks iff = ctrl->in(0)->as_If(); assert(iff->is_If(), "must be if"); // Verify that the other arm is an uncommon trap Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con); CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava(); assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommond trap"); ctrl = iff->in(0); } else { break; } } assert(ctrl->is_Proj(), "must be a projection"); assert(ctrl->in(0)->is_Initialize(), "should be initialize"); for (SimpleDUIterator i(ctrl); i.has_next(); i.next()) { Node* use = i.get(); assert(use == copy || use == iff || use == curr || use->is_CheckCastPP() || use->is_Load(), err_msg_res("unexpected user: %s", use->Name())); } #endif // ASSERT } } } #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print("fusion has correct memory flow for "); _begin->jvms()->dump_spec(tty); tty->cr(); tty->cr(); } #endif return true; } bool StringConcat::validate_control_flow() { // We found all the calls and arguments now lets see if it's // safe to transform the graph as we would expect. // Check to see if this resulted in too many uncommon traps previously if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(), Deoptimization::Reason_intrinsic)) { return false; } // Walk backwards over the control flow from toString to the // allocation and make sure all the control flow is ok. This // means it's either going to be eliminated once the calls are // removed or it can safely be transformed into an uncommon // trap. int null_check_count = 0; Unique_Node_List ctrl_path; assert(_control.contains(_begin), "missing"); assert(_control.contains(_end), "missing"); // Collect the nodes that we know about and will eliminate into ctrl_path for (uint i = 0; i < _control.size(); i++) { // Push the call and it's control projection Node* n = _control.at(i); if (n->is_Allocate()) { AllocateNode* an = n->as_Allocate(); InitializeNode* init = an->initialization(); ctrl_path.push(init); ctrl_path.push(init->as_Multi()->proj_out(0)); } if (n->is_Call()) { CallNode* cn = n->as_Call(); ctrl_path.push(cn); ctrl_path.push(cn->proj_out(0)); ctrl_path.push(cn->proj_out(0)->unique_out()); if (cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0) != NULL) { ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0)); } } else { ShouldNotReachHere(); } } // Skip backwards through the control checking for unexpected control flow Node* ptr = _end; bool fail = false; while (ptr != _begin) { if (ptr->is_Call() && ctrl_path.member(ptr)) { ptr = ptr->in(0); } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) { ptr = ptr->in(0)->in(0)->in(0); assert(ctrl_path.member(ptr), "should be a known piece of control"); } else if (ptr->is_IfTrue()) { IfNode* iff = ptr->in(0)->as_If(); BoolNode* b = iff->in(1)->isa_Bool(); if (b == NULL) { fail = true; break; } Node* cmp = b->in(1); Node* v1 = cmp->in(1); Node* v2 = cmp->in(2); Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con); // Null check of the return of append which can simply be eliminated if (b->_test._test == BoolTest::ne && v2->bottom_type() == TypePtr::NULL_PTR && v1->is_Proj() && ctrl_path.member(v1->in(0))) { // NULL check of the return value of the append null_check_count++; if (otherproj->outcnt() == 1) { CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava(); if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) { ctrl_path.push(call); } } _control.push(ptr); ptr = ptr->in(0)->in(0); continue; } // A test which leads to an uncommon trap which should be safe. // Later this trap will be converted into a trap that restarts // at the beginning. if (otherproj->outcnt() == 1) { CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava(); if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) { // control flow leads to uct so should be ok _uncommon_traps.push(call); ctrl_path.push(call); ptr = ptr->in(0)->in(0); continue; } } #ifndef PRODUCT // Some unexpected control flow we don't know how to handle. if (PrintOptimizeStringConcat) { tty->print_cr("failing with unknown test"); b->dump(); cmp->dump(); v1->dump(); v2->dump(); tty->cr(); } #endif fail = true; break; } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) { ptr = ptr->in(0)->in(0); } else if (ptr->is_Region()) { Node* copy = ptr->as_Region()->is_copy(); if (copy != NULL) { ptr = copy; continue; } if (ptr->req() == 3 && ptr->in(1) != NULL && ptr->in(1)->is_Proj() && ptr->in(2) != NULL && ptr->in(2)->is_Proj() && ptr->in(1)->in(0) == ptr->in(2)->in(0) && ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) { // Simple diamond. // XXX should check for possibly merging stores. simple data merges are ok. // The IGVN will make this simple diamond go away when it // transforms the Region. Make sure it sees it. Compile::current()->record_for_igvn(ptr); ptr = ptr->in(1)->in(0)->in(0); continue; } #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print_cr("fusion would fail for region"); _begin->dump(); ptr->dump(2); } #endif fail = true; break; } else { // other unknown control if (!fail) { #ifndef PRODUCT if (PrintOptimizeStringConcat) { tty->print_cr("fusion would fail for"); _begin->dump(); } #endif fail = true; } #ifndef PRODUCT if (PrintOptimizeStringConcat) { ptr->dump(); } #endif ptr = ptr->in(0); } } #ifndef PRODUCT if (PrintOptimizeStringConcat && fail) { tty->cr(); } #endif if (fail) return !fail; // Validate that all these results produced are contained within // this cluster of objects. First collect all the results produced // by calls in the region. _stringopts->_visited.Clear(); Node_List worklist; Node* final_result = _end->proj_out(TypeFunc::Parms); for (uint i = 0; i < _control.size(); i++) { CallNode* cnode = _control.at(i)->isa_Call(); if (cnode != NULL) { _stringopts->_visited.test_set(cnode->_idx); } Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL; if (result != NULL && result != final_result) { worklist.push(result); } } Node* last_result = NULL; while (worklist.size() > 0) { Node* result = worklist.pop(); if (_stringopts->_visited.test_set(result->_idx)) continue; for (SimpleDUIterator i(result); i.has_next(); i.next()) { Node *use = i.get(); if (ctrl_path.member(use)) { // already checked this continue; } int opc = use->Opcode(); if (opc == Op_CmpP || opc == Op_Node) { ctrl_path.push(use); continue; } if (opc == Op_CastPP || opc == Op_CheckCastPP) { for (SimpleDUIterator j(use); j.has_next(); j.next()) { worklist.push(j.get()); } worklist.push(use->in(1)); ctrl_path.push(use); continue; } #ifndef PRODUCT if (PrintOptimizeStringConcat) { if (result != last_result) { last_result = result; tty->print_cr("extra uses for result:"); last_result->dump(); } use->dump(); } #endif fail = true; break; } } #ifndef PRODUCT if (PrintOptimizeStringConcat && !fail) { ttyLocker ttyl; tty->cr(); tty->print("fusion has correct control flow (%d %d) for ", null_check_count, _uncommon_traps.size()); _begin->jvms()->dump_spec(tty); tty->cr(); for (int i = 0; i < num_arguments(); i++) { argument(i)->dump(); } _control.dump(); tty->cr(); } #endif return !fail; } Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) { const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror()); Node* klass_node = __ makecon(mirror_type); BasicType bt = field->layout_type(); ciType* field_klass = field->type(); const Type *type; if( bt == T_OBJECT ) { if (!field->type()->is_loaded()) { type = TypeInstPtr::BOTTOM; } else if (field->is_constant()) { // This can happen if the constant oop is non-perm. ciObject* con = field->constant_value().as_object(); // Do not "join" in the previous type; it doesn't add value, // and may yield a vacuous result if the field is of interface type. type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr(); assert(type != NULL, "field singleton type must be consistent"); return __ makecon(type); } else { type = TypeOopPtr::make_from_klass(field_klass->as_klass()); } } else { type = Type::get_const_basic_type(bt); } return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()), type, T_OBJECT, C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())), MemNode::unordered); } Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) { RegionNode *final_merge = new RegionNode(3); kit.gvn().set_type(final_merge, Type::CONTROL); Node* final_size = new PhiNode(final_merge, TypeInt::INT); kit.gvn().set_type(final_size, TypeInt::INT); IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne), PROB_FAIR, COUNT_UNKNOWN); Node* is_min = __ IfFalse(iff); final_merge->init_req(1, is_min); final_size->init_req(1, __ intcon(11)); kit.set_control(__ IfTrue(iff)); if (kit.stopped()) { final_merge->init_req(2, C->top()); final_size->init_req(2, C->top()); } else { // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i); RegionNode *r = new RegionNode(3); kit.gvn().set_type(r, Type::CONTROL); Node *phi = new PhiNode(r, TypeInt::INT); kit.gvn().set_type(phi, TypeInt::INT); Node *size = new PhiNode(r, TypeInt::INT); kit.gvn().set_type(size, TypeInt::INT); Node* chk = __ CmpI(arg, __ intcon(0)); Node* p = __ Bool(chk, BoolTest::lt); IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN); Node* lessthan = __ IfTrue(iff); Node* greaterequal = __ IfFalse(iff); r->init_req(1, lessthan); phi->init_req(1, __ SubI(__ intcon(0), arg)); size->init_req(1, __ intcon(1)); r->init_req(2, greaterequal); phi->init_req(2, arg); size->init_req(2, __ intcon(0)); kit.set_control(r); C->record_for_igvn(r); C->record_for_igvn(phi); C->record_for_igvn(size); // for (int i=0; ; i++) // if (x <= sizeTable[i]) // return i+1; // Add loop predicate first. kit.add_predicate(); RegionNode *loop = new RegionNode(3); loop->init_req(1, kit.control()); kit.gvn().set_type(loop, Type::CONTROL); Node *index = new PhiNode(loop, TypeInt::INT); index->init_req(1, __ intcon(0)); kit.gvn().set_type(index, TypeInt::INT); kit.set_control(loop); Node* sizeTable = fetch_static_field(kit, size_table_field); Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS); C->record_for_igvn(value); Node* limit = __ CmpI(phi, value); Node* limitb = __ Bool(limit, BoolTest::le); IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN); Node* lessEqual = __ IfTrue(iff2); Node* greater = __ IfFalse(iff2); loop->init_req(2, greater); index->init_req(2, __ AddI(index, __ intcon(1))); kit.set_control(lessEqual); C->record_for_igvn(loop); C->record_for_igvn(index); final_merge->init_req(2, kit.control()); final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1))); } kit.set_control(final_merge); C->record_for_igvn(final_merge); C->record_for_igvn(final_size); return final_size; } void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) { RegionNode *final_merge = new RegionNode(4); kit.gvn().set_type(final_merge, Type::CONTROL); Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS); kit.gvn().set_type(final_mem, Type::MEMORY); // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive { // i == MIN_VALUE IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne), PROB_FAIR, COUNT_UNKNOWN); Node* old_mem = kit.memory(char_adr_idx); kit.set_control(__ IfFalse(iff)); if (kit.stopped()) { // Statically not equal to MIN_VALUE so this path is dead final_merge->init_req(3, kit.control()); } else { copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())), char_array, start); final_merge->init_req(3, kit.control()); final_mem->init_req(3, kit.memory(char_adr_idx)); } kit.set_control(__ IfTrue(iff)); kit.set_memory(old_mem, char_adr_idx); } // Simplified version of Integer.getChars // int q, r; // int charPos = index; Node* charPos = end; // char sign = 0; Node* i = arg; Node* sign = __ intcon(0); // if (i < 0) { // sign = '-'; // i = -i; // } { IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt), PROB_FAIR, COUNT_UNKNOWN); RegionNode *merge = new RegionNode(3); kit.gvn().set_type(merge, Type::CONTROL); i = new PhiNode(merge, TypeInt::INT); kit.gvn().set_type(i, TypeInt::INT); sign = new PhiNode(merge, TypeInt::INT); kit.gvn().set_type(sign, TypeInt::INT); merge->init_req(1, __ IfTrue(iff)); i->init_req(1, __ SubI(__ intcon(0), arg)); sign->init_req(1, __ intcon('-')); merge->init_req(2, __ IfFalse(iff)); i->init_req(2, arg); sign->init_req(2, __ intcon(0)); kit.set_control(merge); C->record_for_igvn(merge); C->record_for_igvn(i); C->record_for_igvn(sign); } // for (;;) { // q = i / 10; // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ... // buf [--charPos] = digits [r]; // i = q; // if (i == 0) break; // } { // Add loop predicate first. kit.add_predicate(); RegionNode *head = new RegionNode(3); head->init_req(1, kit.control()); kit.gvn().set_type(head, Type::CONTROL); Node *i_phi = new PhiNode(head, TypeInt::INT); i_phi->init_req(1, i); kit.gvn().set_type(i_phi, TypeInt::INT); charPos = PhiNode::make(head, charPos); kit.gvn().set_type(charPos, TypeInt::INT); Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS); kit.gvn().set_type(mem, Type::MEMORY); kit.set_control(head); kit.set_memory(mem, char_adr_idx); Node* q = __ DivI(NULL, i_phi, __ intcon(10)); Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)), __ LShiftI(q, __ intcon(1)))); Node* m1 = __ SubI(charPos, __ intcon(1)); Node* ch = __ AddI(r, __ intcon('0')); Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR), ch, T_CHAR, char_adr_idx, MemNode::unordered); IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne), PROB_FAIR, COUNT_UNKNOWN); Node* ne = __ IfTrue(iff); Node* eq = __ IfFalse(iff); head->init_req(2, ne); mem->init_req(2, st); i_phi->init_req(2, q); charPos->init_req(2, m1); charPos = m1; kit.set_control(eq); kit.set_memory(st, char_adr_idx); C->record_for_igvn(head); C->record_for_igvn(mem); C->record_for_igvn(i_phi); C->record_for_igvn(charPos); } { // if (sign != 0) { // buf [--charPos] = sign; // } IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne), PROB_FAIR, COUNT_UNKNOWN); final_merge->init_req(2, __ IfFalse(iff)); final_mem->init_req(2, kit.memory(char_adr_idx)); kit.set_control(__ IfTrue(iff)); if (kit.stopped()) { final_merge->init_req(1, C->top()); final_mem->init_req(1, C->top()); } else { Node* m1 = __ SubI(charPos, __ intcon(1)); Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR), sign, T_CHAR, char_adr_idx, MemNode::unordered); final_merge->init_req(1, kit.control()); final_mem->init_req(1, st); } kit.set_control(final_merge); kit.set_memory(final_mem, char_adr_idx); C->record_for_igvn(final_merge); C->record_for_igvn(final_mem); } } Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) { Node* string = str; Node* offset = kit.load_String_offset(kit.control(), string); Node* count = kit.load_String_length(kit.control(), string); Node* value = kit.load_String_value (kit.control(), string); // copy the contents if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) { // For small constant strings just emit individual stores. // A length of 6 seems like a good space/speed tradeof. int c = count->get_int(); int o = offset->get_int(); const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr(); ciTypeArray* value_array = t->const_oop()->as_type_array(); for (int e = 0; e < c; e++) { __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR), __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx, MemNode::unordered); start = __ AddI(start, __ intcon(1)); } } else { Node* src_ptr = kit.array_element_address(value, offset, T_CHAR); Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR); Node* c = count; Node* extra = NULL; #ifdef _LP64 c = __ ConvI2L(c); extra = C->top(); #endif Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP, OptoRuntime::fast_arraycopy_Type(), CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()), "jshort_disjoint_arraycopy", TypeAryPtr::CHARS, src_ptr, dst_ptr, c, extra); start = __ AddI(start, count); } return start; } void PhaseStringOpts::replace_string_concat(StringConcat* sc) { // Log a little info about the transformation sc->maybe_log_transform(); // pull the JVMState of the allocation into a SafePointNode to serve as // as a shim for the insertion of the new code. JVMState* jvms = sc->begin()->jvms()->clone_shallow(C); uint size = sc->begin()->req(); SafePointNode* map = new SafePointNode(size, jvms); // copy the control and memory state from the final call into our // new starting state. This allows any preceeding tests to feed // into the new section of code. for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) { map->init_req(i1, sc->end()->in(i1)); } // blow away old allocation arguments for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) { map->init_req(i1, C->top()); } // Copy the rest of the inputs for the JVMState for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) { map->init_req(i1, sc->begin()->in(i1)); } // Make sure the memory state is a MergeMem for parsing. if (!map->in(TypeFunc::Memory)->is_MergeMem()) { map->set_req(TypeFunc::Memory, MergeMemNode::make(map->in(TypeFunc::Memory))); } jvms->set_map(map); map->ensure_stack(jvms, jvms->method()->max_stack()); // disconnect all the old StringBuilder calls from the graph sc->eliminate_unneeded_control(); // At this point all the old work has been completely removed from // the graph and the saved JVMState exists at the point where the // final toString call used to be. GraphKit kit(jvms); // There may be uncommon traps which are still using the // intermediate states and these need to be rewritten to point at // the JVMState at the beginning of the transformation. sc->convert_uncommon_traps(kit, jvms); // Now insert the logic to compute the size of the string followed // by all the logic to construct array and resulting string. Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string())); // Create a region for the overflow checks to merge into. int args = MAX2(sc->num_arguments(), 1); RegionNode* overflow = new RegionNode(args); kit.gvn().set_type(overflow, Type::CONTROL); // Create a hook node to hold onto the individual sizes since they // are need for the copying phase. Node* string_sizes = new Node(args); Node* length = __ intcon(0); for (int argi = 0; argi < sc->num_arguments(); argi++) { Node* arg = sc->argument(argi); switch (sc->mode(argi)) { case StringConcat::IntMode: { Node* string_size = int_stringSize(kit, arg); // accumulate total length = __ AddI(length, string_size); // Cache this value for the use by int_toString string_sizes->init_req(argi, string_size); break; } case StringConcat::StringNullCheckMode: { const Type* type = kit.gvn().type(arg); assert(type != TypePtr::NULL_PTR, "missing check"); if (!type->higher_equal(TypeInstPtr::NOTNULL)) { // Null check with uncommont trap since // StringBuilder(null) throws exception. // Use special uncommon trap instead of // calling normal do_null_check(). Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne); IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN); overflow->add_req(__ IfFalse(iff)); Node* notnull = __ IfTrue(iff); kit.set_control(notnull); // set control for the cast_not_null arg = kit.cast_not_null(arg, false); sc->set_argument(argi, arg); } assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity"); // Fallthrough to add string length. } case StringConcat::StringMode: { const Type* type = kit.gvn().type(arg); Node* count = NULL; if (type == TypePtr::NULL_PTR) { // replace the argument with the null checked version arg = null_string; sc->set_argument(argi, arg); count = kit.load_String_length(kit.control(), arg); } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) { // s = s != null ? s : "null"; // length = length + (s.count - s.offset); RegionNode *r = new RegionNode(3); kit.gvn().set_type(r, Type::CONTROL); Node *phi = new PhiNode(r, type); kit.gvn().set_type(phi, phi->bottom_type()); Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne); IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN); Node* notnull = __ IfTrue(iff); Node* isnull = __ IfFalse(iff); kit.set_control(notnull); // set control for the cast_not_null r->init_req(1, notnull); phi->init_req(1, kit.cast_not_null(arg, false)); r->init_req(2, isnull); phi->init_req(2, null_string); kit.set_control(r); C->record_for_igvn(r); C->record_for_igvn(phi); // replace the argument with the null checked version arg = phi; sc->set_argument(argi, arg); count = kit.load_String_length(kit.control(), arg); } else { // A corresponding nullcheck will be connected during IGVN MemNode::Ideal_common_DU_postCCP // kit.control might be a different test, that can be hoisted above the actual nullcheck // in case, that the control input is not null, Ideal_common_DU_postCCP will not look for a nullcheck. count = kit.load_String_length(NULL, arg); } length = __ AddI(length, count); string_sizes->init_req(argi, NULL); break; } case StringConcat::CharMode: { // one character only length = __ AddI(length, __ intcon(1)); break; } default: ShouldNotReachHere(); } if (argi > 0) { // Check that the sum hasn't overflowed IfNode* iff = kit.create_and_map_if(kit.control(), __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt), PROB_MIN, COUNT_UNKNOWN); kit.set_control(__ IfFalse(iff)); overflow->set_req(argi, __ IfTrue(iff)); } } { // Hook PreserveJVMState pjvms(&kit); kit.set_control(overflow); C->record_for_igvn(overflow); kit.uncommon_trap(Deoptimization::Reason_intrinsic, Deoptimization::Action_make_not_entrant); } Node* result; if (!kit.stopped()) { Node* char_array = NULL; if (sc->num_arguments() == 1 && (sc->mode(0) == StringConcat::StringMode || sc->mode(0) == StringConcat::StringNullCheckMode)) { // Handle the case when there is only a single String argument. // In this case, we can just pull the value from the String itself. char_array = kit.load_String_value(kit.control(), sc->argument(0)); } else { // length now contains the number of characters needed for the // char[] so create a new AllocateArray for the char[] { PreserveReexecuteState preexecs(&kit); // The original jvms is for an allocation of either a String or // StringBuffer so no stack adjustment is necessary for proper // reexecution. If we deoptimize in the slow path the bytecode // will be reexecuted and the char[] allocation will be thrown away. kit.jvms()->set_should_reexecute(true); char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))), length, 1); } // Mark the allocation so that zeroing is skipped since the code // below will overwrite the entire array AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn); char_alloc->maybe_set_complete(_gvn); // Now copy the string representations into the final char[] char_array = __ shenandoah_write_barrier(char_array); Node* start = __ intcon(0); for (int argi = 0; argi < sc->num_arguments(); argi++) { Node* arg = sc->argument(argi); switch (sc->mode(argi)) { case StringConcat::IntMode: { Node* end = __ AddI(start, string_sizes->in(argi)); // getChars words backwards so pass the ending point as well as the start int_getChars(kit, arg, char_array, start, end); start = end; break; } case StringConcat::StringNullCheckMode: case StringConcat::StringMode: { start = copy_string(kit, arg, char_array, start); break; } case StringConcat::CharMode: { __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR), arg, T_CHAR, char_adr_idx, MemNode::unordered); start = __ AddI(start, __ intcon(1)); break; } default: ShouldNotReachHere(); } } } // If we're not reusing an existing String allocation then allocate one here. result = sc->string_alloc(); if (result == NULL) { PreserveReexecuteState preexecs(&kit); // The original jvms is for an allocation of either a String or // StringBuffer so no stack adjustment is necessary for proper // reexecution. kit.jvms()->set_should_reexecute(true); result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass()))); } // Intialize the string if (java_lang_String::has_offset_field()) { kit.store_String_offset(kit.control(), result, __ intcon(0)); kit.store_String_length(kit.control(), result, length); } kit.store_String_value(kit.control(), result, char_array); } else { result = C->top(); } // hook up the outgoing control and result kit.replace_call(sc->end(), result); // Unhook any hook nodes string_sizes->disconnect_inputs(NULL, C); sc->cleanup(); }