src/share/vm/oops/method.cpp

*** 2094,2120 ****
  void Method::clear_jmethod_ids(ClassLoaderData* loader_data) {
    loader_data->jmethod_ids()->clear_all_methods();
  }
  
  bool Method::has_method_vptr(const void* ptr) {
!   Method m;
    // This assumes that the vtbl pointer is the first word of a C++ object.
!   // This assumption is also in universe.cpp patch_klass_vtble
!   void* vtbl2 = dereference_vptr((const void*)&m);
!   void* this_vtbl = dereference_vptr(ptr);
!   return vtbl2 == this_vtbl;
  }
  
  // Check that this pointer is valid by checking that the vtbl pointer matches
  bool Method::is_valid_method() const {
    if (this == NULL) {
      return false;
!   } else if (!is_metaspace_object()) {
      return false;
    } else {
!     return has_method_vptr((const void*)this);
    }
  }
  
  #ifndef PRODUCT
  void Method::print_jmethod_ids(ClassLoaderData* loader_data, outputStream* out) {
    out->print_cr("jni_method_id count = %d", loader_data->jmethod_ids()->count_methods());
--- 2094,2127 ----
  void Method::clear_jmethod_ids(ClassLoaderData* loader_data) {
    loader_data->jmethod_ids()->clear_all_methods();
  }
  
  bool Method::has_method_vptr(const void* ptr) {
!   // Use SafeFetch to check if this is a valid pointer first
    // This assumes that the vtbl pointer is the first word of a C++ object.
!   // This assumption is also in universe.cpp patch_klass_vtable
!   intptr_t this_vptr = SafeFetchN((intptr_t*)ptr, intptr_t(1));
!   if (this_vptr == 1) {
!     return false;
!   }
!   Method m;
!   void* vptr2 = dereference_vptr((const void*)&m);
!   return (intptr_t)vptr2 == this_vptr;
  }
  
  // Check that this pointer is valid by checking that the vtbl pointer matches
  bool Method::is_valid_method() const {
    if (this == NULL) {
      return false;
!   } else {
!     // Quick sanity check on pointer.
!     if ((intptr_t(this) & (wordSize-1)) != 0) {
        return false;
      } else {
!       return has_method_vptr(this);
      }
+   }
  }
  
  #ifndef PRODUCT
  void Method::print_jmethod_ids(ClassLoaderData* loader_data, outputStream* out) {
    out->print_cr("jni_method_id count = %d", loader_data->jmethod_ids()->count_methods());