src/hotspot/share/opto/escape.cpp

rev 60137 : 8227745: Enable Escape Analysis for Better Performance in the Presence of JVMTI Agents
Reviewed-by: mdoerr, goetz

*** 1,7 ****
  /*
!  * Copyright (c) 2005, 2019, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2005, 2020, 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.
*** 121,130 ****
--- 121,131 ----
    GrowableArray<ArrayCopyNode*> arraycopy_worklist;
    GrowableArray<PointsToNode*>   ptnodes_worklist;
    GrowableArray<JavaObjectNode*> java_objects_worklist;
    GrowableArray<JavaObjectNode*> non_escaped_worklist;
    GrowableArray<FieldNode*>      oop_fields_worklist;
+   GrowableArray<SafePointNode*>  sfn_worklist;
    DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
  
    { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
  
    // 1. Populate Connection Graph (CG) with PointsTo nodes.
*** 186,195 ****
--- 187,199 ----
      }
      for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
        Node* m = n->fast_out(i);   // Get user
        ideal_nodes.push(m);
      }
+     if (n-> is_SafePoint()) {
+       sfn_worklist.append(n->as_SafePoint());
+     }
    }
    if (non_escaped_worklist.length() == 0) {
      _collecting = false;
      return false; // Nothing to do.
    }
*** 315,327 ****
--- 319,411 ----
        tty->print(" since AliasLevel < 3 ===");
      }
      tty->cr();
  #endif
    }
+ 
+   // Annotate at safepoints if they have <= ArgEscape objects in their scope and at
+   // java calls if they pass ArgEscape objects as parameters.
+   if (has_non_escaping_obj &&
+       (C->env()->should_retain_local_variables() ||
+        C->env()->jvmti_can_get_owned_monitor_info() ||
+        C->env()->jvmti_can_walk_any_space() ||
+        DeoptimizeObjectsALot)) {
+     int sfn_length = sfn_worklist.length();
+     for (int next = 0; next < sfn_length; next++) {
+       SafePointNode* sfn = sfn_worklist.at(next);
+       sfn->set_not_global_escape_in_scope(has_not_global_escape_in_scope(sfn));
+       if (sfn->is_CallJava()) {
+         CallJavaNode* call = sfn->as_CallJava();
+         call->set_arg_escape(has_arg_escape(call));
+       }
+     }
+   }
+ 
    return has_non_escaping_obj;
  }
  
+ // Returns true if an object in the scope of sfn does not escape globally.
+ bool ConnectionGraph::has_not_global_escape_in_scope(SafePointNode* sfn) {
+   Compile* C = _compile;
+   for (JVMState* jvms = sfn->jvms(); jvms != NULL; jvms = jvms->caller()) {
+     if (C->env()->should_retain_local_variables() || C->env()->jvmti_can_walk_any_space() ||
+         DeoptimizeObjectsALot) {
+       // Jvmti agents can access locals. Must provide info about local objects at runtime.
+       int num_locs = jvms->loc_size();
+       for (int idx = 0; idx < num_locs; idx++) {
+         Node* l = sfn->local(jvms, idx);
+         if (not_global_escape(l)) {
+           return true;
+         }
+       }
+     }
+     if (C->env()->jvmti_can_get_owned_monitor_info() ||
+         C->env()->jvmti_can_walk_any_space() || DeoptimizeObjectsALot) {
+       // Jvmti agents can read monitors. Must provide info about locked objects at runtime.
+       int num_mon = jvms->nof_monitors();
+       for (int idx = 0; idx < num_mon; idx++) {
+         Node* m = sfn->monitor_obj(jvms, idx);
+         if (m != NULL && not_global_escape(m)) {
+           return true;
+         }
+       }
+     }
+   }
+   return false;
+ }
+ 
+ // Returns true if at least one of the arguments to the call is an object
+ // that does not escape globally.
+ bool ConnectionGraph::has_arg_escape(CallJavaNode* call) {
+   if (call->method() != NULL) {
+     uint max_idx = TypeFunc::Parms + call->method()->arg_size();
+     for (uint idx = TypeFunc::Parms; idx < max_idx; idx++) {
+       Node* p = call->in(idx);
+       if (not_global_escape(p)) {
+         return true;
+       }
+     }
+   } else {
+     const char* name = call->as_CallStaticJava()->_name;
+     assert(name != NULL, "no name");
+     // no arg escapes through uncommon traps
+     if (strcmp(name, "uncommon_trap") != 0) {
+       // process_call_arguments() assumes that all arguments escape globally
+       const TypeTuple* d = call->tf()->domain();
+       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
+         const Type* at = d->field_at(i);
+         if (at->isa_oopptr() != NULL) {
+           return true;
+         }
+       }
+     }
+   }
+   return false;
+ }
+ 
+ 
+ 
  // Utility function for nodes that load an object
  void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
    // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
    // ThreadLocal has RawPtr type.
    const Type* t = _igvn->type(n);