jdk-sandbox: comparison hotspot/src/share/vm/opto/stringopts.cpp

equal deleted inserted replaced

-:be1135dc1406
+:5093ad743df4
 /*
-* Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2009, 2013, 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.
 // separate StringBuilders
 Node*               _arguments;      // The list of arguments to be concatenated
 GrowableArray<int>  _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,
 _stringopts(stringopts) {
 _arguments = new (_stringopts->C) 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
 }
 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();
 } 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;
 }
 // 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);
-if (sc->validate_control_flow()) {
+sc->add_constructor(constructor);
+if (sc->validate_control_flow() && sc->validate_mem_flow()) {
 return sc;
 } else {
 return NULL;
 }
 } else if (cnode->method() == NULL) {
 tty->print_cr("considering stacked concats");
 }
 #endif
 StringConcat* merged = sc->merge(other, arg);
-if (merged->validate_control_flow()) {
+if (merged->validate_control_flow() && merged->validate_mem_flow()) {
 #ifndef PRODUCT
 if (PrintOptimizeStringConcat) {
 tty->print_cr("stacking would succeed");
 }
 #endif
 }
 }
 }
+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
 } else {
 ShouldNotReachHere();
 }
 }
-// Skip backwards through the control checking for unexpected contro flow
+// 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);
 #ifndef PRODUCT
 if (PrintOptimizeStringConcat && !fail) {
 ttyLocker ttyl;
 tty->cr();
-tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
+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();

changeset 20716	5093ad743df4
parent 15113	823590505eb4
child 22845	d8812d0ff387