Add routines to fetch target method from MethodHandle and MemberName

runtime/compiler/env/VMJ9.cpp

@@ -4779,6 +4779,58 @@ TR_J9VMBase::methodHandle_jitInvokeExactThunk(uintptr_t methodHandle)
       "invokeExactThunk");
    }
 
+#if defined(J9VM_OPT_OPENJDK_METHODHANDLE)
+TR_OpaqueMethodBlock*
+TR_J9VMBase::targetMethodFromMemberName(TR::Compilation* comp, TR::KnownObjectTable::Index objIndex)
+   {
+   auto knot = comp->getKnownObjectTable();
+   if (objIndex != TR::KnownObjectTable::UNKNOWN &&
+       knot &&
+       !knot->isNull(objIndex))
+      {
+      TR::VMAccessCriticalSection getTarget(this);
+      uintptr_t object = knot->getPointer(objIndex);
+      return targetMethodFromMemberName(object);
+      }
+   return NULL;
+   }
+
+TR_OpaqueMethodBlock*
+TR_J9VMBase::targetMethodFromMemberName(uintptr_t memberName)
+   {
+   TR_ASSERT(haveAccess(), "targetFromMemberName requires VM access");
+   return (TR_OpaqueMethodBlock*)J9OBJECT_U64_LOAD(vmThread(), memberName, vmThread()->javaVM->vmtargetOffset);
+   }
+
+TR_OpaqueMethodBlock*
+TR_J9VMBase::targetMethodFromMethodHandle(TR::Compilation* comp, TR::KnownObjectTable::Index objIndex)
+   {
+   auto knot = comp->getKnownObjectTable();
+   if (objIndex != TR::KnownObjectTable::UNKNOWN &&
+       knot &&
+       !knot->isNull(objIndex))
+      {
+      TR::VMAccessCriticalSection getTarget(this);
+      uintptr_t object = knot->getPointer(objIndex);
+      return targetMethodFromMethodHandle(object);
+      }
+   return NULL;
+   }
+
+TR_OpaqueMethodBlock*
+TR_J9VMBase::targetMethodFromMethodHandle(uintptr_t methodHandle)
+   {
+   TR_ASSERT(haveAccess(), "targetFromMethodHandle requires VM access");
+   uintptr_t form = getReferenceField(
+      methodHandle,
+      "form",             "Ljava/lang/invoke/LambdaForm;");
+   uintptr_t vmentry = getReferenceField(
+      form,
+      "vmentry",             "Ljava/lang/invoke/MemberName;");
+   return targetMethodFromMemberName(vmentry);
+   }
+#endif /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
+
 /**
  * \brief
  *    Check if two java/lang/String objects are equal. Equivalent to java/lang/String.equals.

runtime/compiler/env/VMJ9.h

@@ -754,6 +754,36 @@ class TR_J9VMBase : public TR_FrontEnd
 
    bool hasMethodTypesSideTable();
 
+   // Openjdk implementation
+#if defined(J9VM_OPT_OPENJDK_METHODHANDLE)
+   /*
+    * \brief
+    *    Return MemberName.vmtarget, a J9method pointer for method represented by `memberName`
+    *    Caller must acquire VM access
+    */
+   TR_OpaqueMethodBlock* targetMethodFromMemberName(uintptr_t memberName);
+   /*
+    * \brief
+    *    Return MemberName.vmtarget, a J9method pointer for method represented by `memberName`
+    *    VM access is not required
+    */
+   TR_OpaqueMethodBlock* targetMethodFromMemberName(TR::Compilation* comp, TR::KnownObjectTable::Index objIndex);
+   /*
+    * \brief
+    *    Return MethodHandle.form.vmentry.vmtarget, J9method for the underlying java method
+    *    The J9Method is the target to be invoked intrinsically by MethodHandle.invokeBasic
+    *    Caller must acquire VM access
+    */
+   TR_OpaqueMethodBlock* targetMethodFromMethodHandle(uintptr_t methodHandle);
+   /*
+    * \brief
+    *    Return MethodHandle.form.vmentry.vmtarget, J9method for the underlying java method
+    *    The J9Method is the target to be invoked intrinsically by MethodHandle.invokeBasic
+    *    VM access is not required
+    */
+   TR_OpaqueMethodBlock* targetMethodFromMethodHandle(TR::Compilation* comp, TR::KnownObjectTable::Index objIndex);
+#endif
+
    // JSR292 }}}
 
    virtual uintptr_t getFieldOffset( TR::Compilation * comp, TR::SymbolReference* classRef, TR::SymbolReference* fieldRef);