13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package jdk.vm.ci.hotspot;
  24 
  25 import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
  26 import jdk.vm.ci.code.InstalledCode;
  27 import jdk.vm.ci.code.InvalidInstalledCodeException;
  28 import jdk.vm.ci.meta.JavaKind;
  29 import jdk.vm.ci.meta.JavaType;
  30 import jdk.vm.ci.meta.ResolvedJavaMethod;
  31 
  32 /**
  33  * Implementation of {@link InstalledCode} for code installed as an nmethod. The nmethod stores a
  34  * weak reference to an instance of this class. This is necessary to keep the nmethod from being
  35  * unloaded while the associated {@link HotSpotNmethod} instance is alive.
  36  * <p>
  37  * Note that there is no (current) way for the reference from an nmethod to a {@link HotSpotNmethod}
  38  * instance to be anything but weak. This is due to the fact that HotSpot does not treat nmethods as
  39  * strong GC roots.
  40  */
  41 public class HotSpotNmethod extends HotSpotInstalledCode {
  42 
  43     /**
  44      * This (indirect) Method* reference is safe since class redefinition preserves all methods
  45      * associated with nmethods in the code cache.
  46      */
  47     private final HotSpotResolvedJavaMethod method;
  48 
  49     private final boolean isDefault;
  50 
  51     public HotSpotNmethod(HotSpotResolvedJavaMethod method, String name, boolean isDefault) {
  52         super(name);
  53         this.method = method;
  54         this.isDefault = isDefault;
  55     }
  56 





  57     public boolean isDefault() {
  58         return isDefault;
  59     }
  60 
  61     public ResolvedJavaMethod getMethod() {
  62         return method;
  63     }
  64 
  65     @Override
  66     public void invalidate() {
  67         compilerToVM().invalidateInstalledCode(this);
  68     }
  69 
  70     @Override
  71     public String toString() {
  72         return String.format("InstalledNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s]", method, getAddress(), isDefault, name);
  73     }
  74 
  75     protected boolean checkThreeObjectArgs() {
  76         assert method.getSignature().getParameterCount(!method.isStatic()) == 3;

  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package jdk.vm.ci.hotspot;
  24 
  25 import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
  26 import jdk.vm.ci.code.InstalledCode;
  27 import jdk.vm.ci.code.InvalidInstalledCodeException;
  28 import jdk.vm.ci.meta.JavaKind;
  29 import jdk.vm.ci.meta.JavaType;
  30 import jdk.vm.ci.meta.ResolvedJavaMethod;
  31 
  32 /**
  33  * Implementation of {@link InstalledCode} for code installed as an nmethod.
  34  *
  35  * When a {@link HotSpotNmethod} dies, it triggers unloading of the nmethod unless
  36  * {@link #isDefault() == true}.



  37  */
  38 public class HotSpotNmethod extends HotSpotInstalledCode {
  39 
  40     /**
  41      * This (indirect) Method* reference is safe since class redefinition preserves all methods
  42      * associated with nmethods in the code cache.
  43      */
  44     private final HotSpotResolvedJavaMethod method;
  45 
  46     private final boolean isDefault;
  47 
  48     public HotSpotNmethod(HotSpotResolvedJavaMethod method, String name, boolean isDefault) {
  49         super(name);
  50         this.method = method;
  51         this.isDefault = isDefault;
  52     }
  53 
  54     /**
  55      * Determines if the nmethod associated with this object is the compiled entry point for
  56      * {@link #getMethod()}. If {@code false}, then the nmethod is unloaded when the VM determines
  57      * this object has died.
  58      */
  59     public boolean isDefault() {
  60         return isDefault;
  61     }
  62 
  63     public ResolvedJavaMethod getMethod() {
  64         return method;
  65     }
  66 
  67     @Override
  68     public void invalidate() {
  69         compilerToVM().invalidateInstalledCode(this);
  70     }
  71 
  72     @Override
  73     public String toString() {
  74         return String.format("InstalledNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s]", method, getAddress(), isDefault, name);
  75     }
  76 
  77     protected boolean checkThreeObjectArgs() {
  78         assert method.getSignature().getParameterCount(!method.isStatic()) == 3;