6920293: OptimizeStringConcat causing core dumps

Reviewed-by: kvn, twisti

src/os_cpu/solaris_x86/vm/os_solaris_x86.cpp

 /*
- * Copyright 1999-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1999-2010 Sun Microsystems, Inc.  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
@@ -730,11 +730,12 @@ void os::print_context(outputStream *st, void *context) {
   st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
   st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
   st->cr();
-  st->print(", R8=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
+  st->print(  "R8=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
   st->print(", R9=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
   st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
   st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
-  st->print(", R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
+  st->cr();
+  st->print(  "R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
   st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
   st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
   st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);

src/share/vm/code/nmethod.cpp

@@ -2010,7 +2010,10 @@ address nmethod::continuation_for_implicit_exception(address pc) {
     print_pcs();
   }
 #endif
-  guarantee(cont_offset != 0, "unhandled implicit exception in compiled code");
+  if (cont_offset == 0) {
+    // Let the normal error handling report the exception
+    return NULL;
+  }
   return instructions_begin() + cont_offset;
 }
 

src/share/vm/opto/stringopts.cpp

 /*
- * Copyright 2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2009-2010 Sun Microsystems, Inc.  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
@@ -1073,7 +1073,7 @@ void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, N
     kit.set_control(head);
     kit.set_memory(mem, char_adr_idx);
 
-    Node* q = __ DivI(kit.null(), i_phi, __ intcon(10));
+    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));
@@ -1270,14 +1270,15 @@ void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
           // length = length + (s.count - s.offset);
           RegionNode *r = new (C, 3) RegionNode(3);
           kit.gvn().set_type(r, Type::CONTROL);
-          Node *phi = new (C, 3) PhiNode(r, type->join(TypeInstPtr::NOTNULL));
+          Node *phi = new (C, 3) 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, arg);
+          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);

src/share/vm/runtime/sharedRuntime.cpp

@@ -607,7 +607,9 @@ address SharedRuntime::continuation_for_implicit_exception(JavaThread* thread,
           _implicit_null_throws++;
 #endif
           target_pc = nm->continuation_for_implicit_exception(pc);
-          guarantee(target_pc != 0, "must have a continuation point");
+          // If there's an unexpected fault, target_pc might be NULL,
+          // in which case we want to fall through into the normal
+          // error handling code.
         }
 
         break; // fall through
@@ -621,14 +623,15 @@ address SharedRuntime::continuation_for_implicit_exception(JavaThread* thread,
         _implicit_div0_throws++;
 #endif
         target_pc = nm->continuation_for_implicit_exception(pc);
-        guarantee(target_pc != 0, "must have a continuation point");
+        // If there's an unexpected fault, target_pc might be NULL,
+        // in which case we want to fall through into the normal
+        // error handling code.
         break; // fall through
       }
 
       default: ShouldNotReachHere();
     }
 
-    guarantee(target_pc != NULL, "must have computed destination PC for implicit exception");
     assert(exception_kind == IMPLICIT_NULL || exception_kind == IMPLICIT_DIVIDE_BY_ZERO, "wrong implicit exception kind");
 
     // for AbortVMOnException flag