diff src/share/vm/opto/compile.hpp @ 5223:edb5ab0f3fe5

8001107: @Stable annotation for constant folding of lazily evaluated variables Reviewed-by: rbackman, twisti, kvn Contributed-by: john.r.rose@oracle.com, vladimir.x.ivanov@oracle.com
author vlivanov
date Tue, 10 Sep 2013 14:51:48 -0700
parents f2110083203d
children 1b64d46620a3
line wrap: on
line diff
--- a/src/share/vm/opto/compile.hpp	Mon Sep 09 19:53:28 2013 +0200
+++ b/src/share/vm/opto/compile.hpp	Tue Sep 10 14:51:48 2013 -0700
@@ -72,6 +72,7 @@
 class StartNode;
 class SafePointNode;
 class JVMState;
+class Type;
 class TypeData;
 class TypePtr;
 class TypeOopPtr;
@@ -119,6 +120,7 @@
     int             _index;         // unique index, used with MergeMemNode
     const TypePtr*  _adr_type;      // normalized address type
     ciField*        _field;         // relevant instance field, or null if none
+    const Type*     _element;       // relevant array element type, or null if none
     bool            _is_rewritable; // false if the memory is write-once only
     int             _general_index; // if this is type is an instance, the general
                                     // type that this is an instance of
@@ -129,6 +131,7 @@
     int             index()         const { return _index; }
     const TypePtr*  adr_type()      const { return _adr_type; }
     ciField*        field()         const { return _field; }
+    const Type*     element()       const { return _element; }
     bool            is_rewritable() const { return _is_rewritable; }
     bool            is_volatile()   const { return (_field ? _field->is_volatile() : false); }
     int             general_index() const { return (_general_index != 0) ? _general_index : _index; }
@@ -137,7 +140,14 @@
     void set_field(ciField* f) {
       assert(!_field,"");
       _field = f;
-      if (f->is_final())  _is_rewritable = false;
+      if (f->is_final() || f->is_stable()) {
+        // In the case of @Stable, multiple writes are possible but may be assumed to be no-ops.
+        _is_rewritable = false;
+      }
+    }
+    void set_element(const Type* e) {
+      assert(_element == NULL, "");
+      _element = e;
     }
 
     void print_on(outputStream* st) PRODUCT_RETURN;