var memory_manager: MemoryManager = new MemoryManager
# The unique instance of the `MInit` value
- var initialization_value: Instance
+ var initialization_value: Instance is noinit
- init(modelbuilder: ModelBuilder, mainmodule: MModule, arguments: Array[String])
+ init
do
var init_type = new MInitType(mainmodule.model)
initialization_value = new MutableInstance(init_type)
var super_id = sup.mclass.vtable.id
var mask = sub.mclass.vtable.mask
- return inter_is_subtype(super_id, mask, sub.mclass.vtable.internal_vtable)
+ # For now, we always use perfect hashing for subtyping test
+ return inter_is_subtype_ph(super_id, mask, sub.mclass.vtable.internal_vtable)
end
# Subtyping test with perfect hashing
- private fun inter_is_subtype(id: Int, mask:Int, vtable: Pointer): Bool `{
+ private fun inter_is_subtype_ph(id: Int, mask:Int, vtable: Pointer): Bool `{
// hv is the position in hashtable
int hv = id & mask;
return *offset == id;
`}
+ # Subtyping test with Cohen test (direct access)
+ private fun inter_is_subtype_sst(id: Int, position: Int, vtable: Pointer): Bool `{
+ // Direct access to the position given in parameter
+ int tableid = (long unsigned int)((long int *)vtable)[position];
+
+ return id == tableid;
+ `}
+
# Redef init_instance to simulate the loading of a class
redef fun init_instance(recv: Instance)
do
var ret = send_commons(mproperty, args, mtype)
if ret != null then return ret
- var propdef = method_dispatch(mproperty, recv.vtable.as(not null))
+ var propdef = method_dispatch(mproperty, recv.vtable.as(not null), recv)
return self.call(propdef, args)
end
# Method dispatch, for a given global method `mproperty`
# returns the most specific local method in the class corresponding to `vtable`
- private fun method_dispatch(mproperty: MMethod, vtable: VTable): MMethodDef
+ private fun method_dispatch(mproperty: MMethod, vtable: VTable, recv: Instance): MMethodDef
do
- return method_dispatch_ph(vtable.internal_vtable, vtable.mask,
+ if mproperty.intro_mclassdef.mclass.positions_methods[recv.mtype.as(MClassType).mclass] != -1 then
+ return method_dispatch_sst(vtable.internal_vtable, mproperty.absolute_offset)
+ else
+ return method_dispatch_ph(vtable.internal_vtable, vtable.mask,
mproperty.intro_mclassdef.mclass.vtable.id, mproperty.offset)
+ end
end
# Execute a method dispatch with perfect hashing
return propdef;
`}
+ # Execute a method dispatch with direct access and return the appropriate `MMethodDef`
+ # `vtable` : Pointer to the internal pointer of the class
+ # `absolute_offset` : Absolute offset from the beginning of the virtual table
+ private fun method_dispatch_sst(vtable: Pointer, absolute_offset: Int): MMethodDef `{
+ // pointer+2 is the position where methods are
+ // Add the offset of property and get the method implementation
+ MMethodDef propdef = (MMethodDef)((long int *)vtable)[absolute_offset];
+
+ return propdef;
+ `}
+
# Return the value of the attribute `mproperty` for the object `recv`
redef fun read_attribute(mproperty: MAttribute, recv: Instance): Instance
do
end
# Return the attribute value in `instance` with a sequence of perfect_hashing
- # `instance` is the attributes array of the receiver
- # `vtable` is the pointer to the virtual table of the class (of the receiver)
- # `mask` is the perfect hashing mask of the class
- # `id` is the identifier of the class
- # `offset` is the relative offset of this attribute
+ # * `instance` is the attributes array of the receiver
+ # * `vtable` is the pointer to the virtual table of the class (of the receiver)
+ # * `mask` is the perfect hashing mask of the class
+ # * `id` is the identifier of the class
+ # * `offset` is the relative offset of this attribute
private fun read_attribute_ph(instance: Pointer, vtable: Pointer, mask: Int, id: Int, offset: Int): Instance `{
// Perfect hashing position
int hv = mask & id;
`}
# Return the attribute value in `instance` with a direct access (SST)
- # `instance` is the attributes array of the receiver
- # `offset` is the absolute offset of this attribute
+ # * `instance` is the attributes array of the receiver
+ # * `offset` is the absolute offset of this attribute
private fun read_attribute_sst(instance: Pointer, offset: Int): Instance `{
/* We can make a direct access to the attribute value
because this attribute is always at the same position
end
# Replace the value of an attribute in an instance
- # `instance` is the attributes array of the receiver
- # `vtable` is the pointer to the virtual table of the class (of the receiver)
- # `mask` is the perfect hashing mask of the class
- # `id` is the identifier of the class
- # `offset` is the relative offset of this attribute
- # `value` is the new value for this attribute
+ # * `instance` is the attributes array of the receiver
+ # * `vtable` is the pointer to the virtual table of the class (of the receiver)
+ # * `mask` is the perfect hashing mask of the class
+ # * `id` is the identifier of the class
+ # * `offset` is the relative offset of this attribute
+ # * `value` is the new value for this attribute
private fun write_attribute_ph(instance: Pointer, vtable: Pointer, mask: Int, id: Int, offset: Int, value: Instance) `{
// Perfect hashing position
int hv = mask & id;
`}
# Replace the value of an attribute in an instance with direct access
- # `instance` is the attributes array of the receiver
- # `offset` is the absolute offset of this attribute
- # `value` is the new value for this attribute
+ # * `instance` is the attributes array of the receiver
+ # * `offset` is the absolute offset of this attribute
+ # * `value` is the new value for this attribute
private fun write_attribute_sst(instance: Pointer, offset: Int, value: Instance) `{
// Direct access to the position with the absolute offset
((Instance *)instance)[offset] = value;
# True when the class is effectively loaded by the vm, false otherwise
var loaded: Bool = false
+ # Color for Cohen subtyping test : the absolute position of the id
+ # of this class in virtual tables
+ var color: Int
+
# For each loaded subclass, keep the position of the group of attributes
# introduced by self class in the object
var positions_attributes: HashMap[MClass, Int] = new HashMap[MClass, Int]
# Absolute offset of attribute from the beginning of the attributes table
var offset_attributes = 0
- # Absolute offset of method from the beginning of the methods table
- var offset_methods = 0
+
+ # Absolute offset of method from the beginning of the methods table,
+ # is initialize to 3 because the first position is empty in the virtual table
+ # and the second and third are respectively class id and delta
+ var offset_methods = 3
# The previous element in `superclasses`
var previous_parent: nullable MClass = null
offset_attributes += attributes
offset_methods += methods
+ offset_methods += 2 # Because each block starts with an id and the delta
end
# When all super-classes have their identifiers and vtables, allocate current one
allocate_vtable(v, ids, nb_methods, nb_attributes, offset_attributes, offset_methods)
loaded = true
+ # Set the absolute position of the identifier of this class in the virtual table
+ color = offset_methods - 2
+
# The virtual table now needs to be filled with pointer to methods
superclasses.add(self)
for cl in superclasses do
end
# Allocate a single vtable
- # `ids : Array of superclasses identifiers
- # `nb_methods : Array which contain the number of introduced methods for each class in ids
- # `nb_attributes : Array which contain the number of introduced attributes for each class in ids
- # `offset_attributes : Offset from the beginning of the table of the group of attributes
- # `offset_methods : Offset from the beginning of the table of the group of methods
+ # * `ids : Array of superclasses identifiers
+ # * `nb_methods : Array which contain the number of introduced methods for each class in ids
+ # * `nb_attributes : Array which contain the number of introduced attributes for each class in ids
+ # * `offset_attributes : Offset from the beginning of the table of the group of attributes
+ # * `offset_methods : Offset from the beginning of the table of the group of methods
private fun allocate_vtable(v: VirtualMachine, ids: Array[Int], nb_methods: Array[Int], nb_attributes: Array[Int],
offset_attributes: Int, offset_methods: Int)
do
end
# Fill the vtable with methods of `self` class
- # `v` : Current instance of the VirtualMachine
- # `table` : the table of self class, will be filled with its methods
+ # * `v` : Current instance of the VirtualMachine
+ # * `table` : the table of self class, will be filled with its methods
private fun fill_vtable(v:VirtualMachine, table: VTable, cl: MClass)
do
var methods = new Array[MMethodDef]
# Computes delta for each class
# A delta represents the offset for this group of attributes in the object
- # `nb_attributes` : number of attributes for each class (classes are linearized from Object to current)
- # return deltas for each class
+ # *`nb_attributes` : number of attributes for each class (classes are linearized from Object to current)
+ # * return deltas for each class
private fun calculate_delta(nb_attributes: Array[Int]): Array[Int]
do
var deltas = new Array[Int]
end
# A kind of Depth-First-Search for superclasses ordering
- # `v` : the current executed instance of VirtualMachine
- # `res` : Result Array, ie current superclasses ordering
+ # *`v` : the current executed instance of VirtualMachine
+ # * `res` : Result Array, ie current superclasses ordering
private fun dfs(v: VirtualMachine, res: Array[MClass]): Array[MClass]
do
# Add this class at the beginning
end
# Update positions of the class `cl`
- # `attributes_offset`: absolute offset of introduced attributes
- # `methods_offset`: absolute offset of introduced methods
+ # * `attributes_offset`: absolute offset of introduced attributes
+ # * `methods_offset`: absolute offset of introduced methods
private fun update_positions(attributes_offsets: Int, methods_offset:Int, cl: MClass)
do
positions_attributes[cl] = attributes_offsets
# Redef to associate an `Instance` to its `VTable`
redef class Instance
+
+ # Associate a runtime instance to its virtual table which contains methods, types etc.
var vtable: nullable VTable
end
super MType
redef var model: Model
- protected init(model: Model)
- do
- self.model = model
- end
redef fun to_s do return "InitType"
redef fun as_nullable do return self
`}
# Put implementation of methods of a class in `vtable`
- # `vtable` : Pointer to the C-virtual table
- # `mask` : perfect-hashing mask of the class corresponding to the vtable
- # `id` : id of the target class
- # `methods` : array of MMethodDef of the target class
+ # * `vtable` : Pointer to the C-virtual table
+ # * `mask` : perfect-hashing mask of the class corresponding to the vtable
+ # * `id` : id of the target class
+ # * `methods` : array of MMethodDef of the target class
fun put_methods(vtable: Pointer, mask: Int, id: Int, methods: Array[MMethodDef])
import Array[MMethodDef].length, Array[MMethodDef].[] `{
nitlanguage / nit.git / blobdiff