8007901: SA: Don't read flag values as constants

Reviewed-by: dholmes, mikael

agent/src/share/classes/sun/jvm/hotspot/runtime/VM.java

@@ -90,10 +90,6 @@ public class VM {
   /** Flags indicating whether we are attached to a core, C1, or C2 build */
   private boolean      usingClientCompiler;
   private boolean      usingServerCompiler;
-  /** Flag indicating whether UseTLAB is turned on */
-  private boolean      useTLAB;
-  /** Flag indicating whether invokedynamic support is on */
-  private boolean      enableInvokeDynamic;
   /** alignment constants */
   private boolean      isLP64;
   private int          bytesPerLong;
@@ -326,9 +322,6 @@ public class VM {
       }
     }
 
-    useTLAB = (db.lookupIntConstant("UseTLAB").intValue() != 0);
-    enableInvokeDynamic = (db.lookupIntConstant("EnableInvokeDynamic").intValue() != 0);
-
     if (debugger != null) {
       isLP64 = debugger.getMachineDescription().isLP64();
     }
@@ -579,15 +572,6 @@ public class VM {
     }
   }
 
-  /** Indicates whether Thread-Local Allocation Buffers are used */
-  public boolean getUseTLAB() {
-    return useTLAB;
-  }
-
-  public boolean getEnableInvokeDynamic() {
-    return enableInvokeDynamic;
-  }
-
   public TypeDataBase getTypeDataBase() {
     return db;
   }
@@ -822,6 +806,12 @@ public class VM {
     return objectAlignmentInBytes;
   }
 
+  /** Indicates whether Thread-Local Allocation Buffers are used */
+  public boolean getUseTLAB() {
+      Flag flag = getCommandLineFlag("UseTLAB");
+      return (flag == null) ? false: flag.getBool();
+  }
+
   // returns null, if not available.
   public Flag[] getCommandLineFlags() {
     if (commandLineFlags == null) {

src/share/vm/runtime/vmStructs.cpp

@@ -2109,8 +2109,6 @@ typedef BinaryTreeDictionary<Metablock, FreeList> MetablockTreeDictionary;
   /* Useful globals */                                                    \
   /******************/                                                    \
                                                                           \
-  declare_constant(UseTLAB)                                               \
-  declare_constant(EnableInvokeDynamic)                                   \
                                                                           \
   /**************/                                                        \
   /* Stack bias */                                                        \