| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- A D A . T A G S -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- |
| -- -- |
| -- This specification is derived from the Ada Reference Manual for use with -- |
| -- GNAT. The copyright notice above, and the license provisions that follow -- |
| -- apply solely to the contents of the part following the private keyword. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 2, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- |
| -- Boston, MA 02110-1301, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- unit, or you link this unit with other files to produce an executable, -- |
| -- this unit does not by itself cause the resulting executable to be -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with System; |
| with System.Storage_Elements; |
| with Unchecked_Conversion; |
| |
| package Ada.Tags is |
| pragma Preelaborate_05; |
| -- In accordance with Ada 2005 AI-362 |
| |
| type Tag is private; |
| |
| No_Tag : constant Tag; |
| |
| function Expanded_Name (T : Tag) return String; |
| |
| function External_Tag (T : Tag) return String; |
| |
| function Internal_Tag (External : String) return Tag; |
| |
| function Descendant_Tag |
| (External : String; |
| Ancestor : Tag) return Tag; |
| pragma Ada_05 (Descendant_Tag); |
| |
| function Is_Descendant_At_Same_Level |
| (Descendant : Tag; |
| Ancestor : Tag) return Boolean; |
| pragma Ada_05 (Is_Descendant_At_Same_Level); |
| |
| function Parent_Tag (T : Tag) return Tag; |
| pragma Ada_05 (Parent_Tag); |
| |
| Tag_Error : exception; |
| |
| function Wide_Expanded_Name (T : Tag) return Wide_String; |
| pragma Ada_05 (Wide_Expanded_Name); |
| |
| function Wide_Wide_Expanded_Name (T : Tag) return Wide_Wide_String; |
| pragma Ada_05 (Wide_Wide_Expanded_Name); |
| |
| private |
| -- The following subprogram specifications are placed here instead of |
| -- the package body to see them from the frontend through rtsfind. |
| |
| --------------------------------------------------------------- |
| -- Abstract Procedural Interface For The GNAT Dispatch Table -- |
| --------------------------------------------------------------- |
| |
| -- GNAT's Dispatch Table format is customizable in order to match the |
| -- format used in another language. GNAT supports programs that use two |
| -- different dispatch table formats at the same time: the native format |
| -- that supports Ada 95 tagged types and which is described in Ada.Tags, |
| -- and a foreign format for types that are imported from some other |
| -- language (typically C++) which is described in Interfaces.CPP. The |
| -- runtime information kept for each tagged type is separated into two |
| -- objects: the Dispatch Table and the Type Specific Data record. These |
| -- two objects are allocated statically using the constants: |
| |
| -- DT Size = DT_Prologue_Size + Nb_Prim * DT_Entry_Size |
| -- TSD Size = TSD_Prologue_Size + (1 + Idepth) * TSD_Entry_Size |
| |
| -- where Nb_prim is the number of primitive operations of the given |
| -- type and Idepth its inheritance depth. |
| |
| -- In order to set or retrieve information from the Dispatch Table or |
| -- the Type Specific Data record, GNAT generates calls to Set_XXX or |
| -- Get_XXX routines, where XXX is the name of the field of interest. |
| |
| type Dispatch_Table; |
| type Tag is access all Dispatch_Table; |
| type Interface_Tag is access all Dispatch_Table; |
| |
| No_Tag : constant Tag := null; |
| |
| type Interface_Data (Nb_Ifaces : Positive); |
| type Interface_Data_Ptr is access all Interface_Data; |
| -- Table of abstract interfaces used to give support to backward interface |
| -- conversions and also to IW_Membership. |
| |
| type Object_Specific_Data (Nb_Prim : Positive); |
| type Object_Specific_Data_Ptr is access all Object_Specific_Data; |
| -- Information associated with the secondary dispatch table of tagged-type |
| -- objects implementing abstract interfaces. |
| |
| type Select_Specific_Data (Nb_Prim : Positive); |
| type Select_Specific_Data_Ptr is access all Select_Specific_Data; |
| -- A table used to store the primitive operation kind and entry index of |
| -- primitive subprograms of a type that implements a limited interface. |
| -- The Select Specific Data table resides in the Type Specific Data of a |
| -- type. This construct is used in the handling of dispatching triggers |
| -- in select statements. |
| |
| type Type_Specific_Data; |
| type Type_Specific_Data_Ptr is access all Type_Specific_Data; |
| |
| -- Primitive operation kinds. These values differentiate the kinds of |
| -- callable entities stored in the dispatch table. Certain kinds may |
| -- not be used, but are added for completeness. |
| |
| type Prim_Op_Kind is |
| (POK_Function, |
| POK_Procedure, |
| POK_Protected_Entry, |
| POK_Protected_Function, |
| POK_Protected_Procedure, |
| POK_Task_Entry, |
| POK_Task_Function, |
| POK_Task_Procedure); |
| |
| -- Tagged type kinds with respect to concurrency and limitedness |
| |
| type Tagged_Kind is |
| (TK_Abstract_Limited_Tagged, |
| TK_Abstract_Tagged, |
| TK_Limited_Tagged, |
| TK_Protected, |
| TK_Tagged, |
| TK_Task); |
| |
| type Tagged_Kind_Ptr is access all Tagged_Kind; |
| |
| Default_Prim_Op_Count : constant Positive := 15; |
| -- Number of predefined primitive operations added by the Expander for a |
| -- tagged type (must match Exp_Disp.Default_Prim_Op_Count). |
| |
| type Signature_Kind is |
| (Unknown, |
| Valid_Signature, |
| Primary_DT, |
| Secondary_DT, |
| Abstract_Interface); |
| for Signature_Kind'Size use 8; |
| -- Kind of signature found in the header of the dispatch table. These |
| -- signatures are generated by the frontend and are used by the Check_XXX |
| -- routines to ensure that the kind of dispatch table managed by each of |
| -- the routines in this package is correct. This additional check is only |
| -- performed with this run-time package is compiled with assertions enabled |
| |
| -- The signature is a sequence of two bytes. The first byte must have the |
| -- value Valid_Signature, and the second byte must have a value in the |
| -- range Primary_DT .. Abstract_Interface. The Unknown value is used by |
| -- the Check_XXX routines to indicate that the signature is wrong. |
| |
| package SSE renames System.Storage_Elements; |
| |
| function CW_Membership (Obj_Tag : Tag; Typ_Tag : Tag) return Boolean; |
| -- Given the tag of an object and the tag associated to a type, return |
| -- true if Obj is in Typ'Class. |
| |
| function IW_Membership (This : System.Address; T : Tag) return Boolean; |
| -- Ada 2005 (AI-251): General routine that checks if a given object |
| -- implements a tagged type. Its common usage is to check if Obj is in |
| -- Iface'Class, but it is also used to check if a class-wide interface |
| -- implements a given type (Iface_CW_Typ in T'Class). For example: |
| -- |
| -- type I is interface; |
| -- type T is tagged ... |
| -- |
| -- function Test (O : in I'Class) is |
| -- begin |
| -- return O in T'Class. |
| -- end Test; |
| |
| function Displace (This : System.Address; T : Tag) return System.Address; |
| -- (Ada 2005 (AI-251): Displace "This" to point to the secondary dispatch |
| -- table of T. |
| |
| function Get_Access_Level (T : Tag) return Natural; |
| -- Given the tag associated with a type, returns the accessibility level |
| -- of the type. |
| |
| function Get_Entry_Index (T : Tag; Position : Positive) return Positive; |
| -- Return a primitive operation's entry index (if entry) given a dispatch |
| -- table T and a position of a primitive operation in T. |
| |
| function Get_External_Tag (T : Tag) return System.Address; |
| -- Retrieve the address of a null terminated string containing |
| -- the external name. |
| |
| function Get_Offset_Index |
| (T : Tag; |
| Position : Positive) return Positive; |
| -- Given a pointer to a secondary dispatch table (T) and a position of an |
| -- operation in the DT, retrieve the corresponding operation's position in |
| -- the primary dispatch table from the Offset Specific Data table of T. |
| |
| function Get_Predefined_Prim_Op_Address |
| (T : Tag; |
| Position : Positive) return System.Address; |
| -- Given a pointer to a dispatch table (T) and a position in the DT |
| -- this function returns the address of the virtual function stored |
| -- in it (used for dispatching calls). |
| |
| function Get_Prim_Op_Address |
| (T : Tag; |
| Position : Positive) return System.Address; |
| -- Given a pointer to a dispatch table (T) and a position in the DT |
| -- this function returns the address of the virtual function stored |
| -- in it (used for dispatching calls). |
| |
| function Get_Prim_Op_Kind |
| (T : Tag; |
| Position : Positive) return Prim_Op_Kind; |
| -- Return a primitive operation's kind given a dispatch table T and a |
| -- position of a primitive operation in T. |
| |
| function Get_RC_Offset (T : Tag) return SSE.Storage_Offset; |
| -- Return the Offset of the implicit record controller when the object |
| -- has controlled components. O otherwise. |
| |
| pragma Export (Ada, Get_RC_Offset, "ada__tags__get_rc_offset"); |
| -- This procedure is used in s-finimp to compute the deep routines |
| -- it is exported manually in order to avoid changing completely the |
| -- organization of the run time. |
| |
| function Get_Remotely_Callable (T : Tag) return Boolean; |
| -- Return the value previously set by Set_Remotely_Callable |
| |
| function Get_Tagged_Kind (T : Tag) return Tagged_Kind; |
| -- Given a pointer to either a primary or a secondary dispatch table, |
| -- return the tagged kind of a type in the context of concurrency and |
| -- limitedness. |
| |
| procedure Inherit_DT (Old_T : Tag; New_T : Tag; Entry_Count : Natural); |
| -- Entry point used to initialize the DT of a type knowing the tag |
| -- of the direct ancestor and the number of primitive ops that are |
| -- inherited (Entry_Count). |
| |
| procedure Inherit_TSD (Old_Tag : Tag; New_Tag : Tag); |
| -- Initialize the TSD of a type knowing the tag of the direct ancestor |
| |
| function Offset_To_Top |
| (This : System.Address) return System.Storage_Elements.Storage_Offset; |
| -- Returns the current value of the offset_to_top component available in |
| -- the prologue of the dispatch table. If the parent of the tagged type |
| -- has discriminants this value is stored in a record component just |
| -- immediately after the tag component. |
| |
| function OSD (T : Tag) return Object_Specific_Data_Ptr; |
| -- Ada 2005 (AI-251): Given a pointer T to a secondary dispatch table, |
| -- retrieve the address of the record containing the Objet Specific |
| -- Data table. |
| |
| function Parent_Size |
| (Obj : System.Address; |
| T : Tag) return SSE.Storage_Count; |
| -- Computes the size the ancestor part of a tagged extension object whose |
| -- address is 'obj' by calling indirectly the ancestor _size function. The |
| -- ancestor is the parent of the type represented by tag T. This function |
| -- assumes that _size is always in slot one of the dispatch table. |
| |
| pragma Export (Ada, Parent_Size, "ada__tags__parent_size"); |
| -- This procedure is used in s-finimp and is thus exported manually |
| |
| procedure Register_Interface_Tag |
| (T : Tag; |
| Interface_T : Tag; |
| Position : Positive); |
| -- Ada 2005 (AI-251): Used to initialize the table of interfaces |
| -- implemented by a type. Required to give support to backward interface |
| -- conversions and also to IW_Membership. |
| |
| procedure Register_Tag (T : Tag); |
| -- Insert the Tag and its associated external_tag in a table for the |
| -- sake of Internal_Tag |
| |
| procedure Set_Access_Level (T : Tag; Value : Natural); |
| -- Sets the accessibility level of the tagged type associated with T |
| -- in its TSD. |
| |
| procedure Set_Entry_Index (T : Tag; Position : Positive; Value : Positive); |
| -- Set the entry index of a primitive operation in T's TSD table indexed |
| -- by Position. |
| |
| procedure Set_Expanded_Name (T : Tag; Value : System.Address); |
| -- Set the address of the string containing the expanded name |
| -- in the Dispatch table. |
| |
| procedure Set_External_Tag (T : Tag; Value : System.Address); |
| -- Set the address of the string containing the external tag |
| -- in the Dispatch table. |
| |
| procedure Set_Interface_Table (T : Tag; Value : System.Address); |
| -- Ada 2005 (AI-251): Given a pointer T to a dispatch Table, stores the |
| -- pointer to the table of interfaces. |
| |
| procedure Set_Num_Prim_Ops (T : Tag; Value : Natural); |
| -- Set the number of primitive operations in the dispatch table of T. This |
| -- is used for debugging purposes. |
| |
| procedure Set_Offset_Index |
| (T : Tag; |
| Position : Positive; |
| Value : Positive); |
| -- Set the offset value of a primitive operation in a secondary dispatch |
| -- table denoted by T, indexed by Position. |
| |
| procedure Set_Offset_To_Top |
| (This : System.Address; |
| Interface_T : Tag; |
| Is_Static : Boolean; |
| Offset_Value : System.Storage_Elements.Storage_Offset; |
| Offset_Func : System.Address); |
| -- Ada 2005 (AI-251): Initialize the Offset_To_Top field in the prologue of |
| -- the dispatch table. In primary dispatch tables the value of "This" is |
| -- not required (and the compiler passes always the Null_Address value) and |
| -- the Offset_Value is always cero; in secondary dispatch tables "This" |
| -- points to the object, Interface_T is the interface for which the |
| -- secondary dispatch table is being initialized, and Offset_Value is the |
| -- distance from "This" to the object component containing the tag of the |
| -- secondary dispatch table. |
| |
| procedure Set_OSD (T : Tag; Value : System.Address); |
| -- Given a pointer T to a secondary dispatch table, store the pointer to |
| -- the record containing the Object Specific Data generated by GNAT. |
| |
| procedure Set_Predefined_Prim_Op_Address |
| (T : Tag; |
| Position : Positive; |
| Value : System.Address); |
| -- Given a pointer to a dispatch Table (T) and a position in the dispatch |
| -- table associated with a predefined primitive operation, put the address |
| -- of the virtual function in it (used for overriding). |
| |
| procedure Set_Prim_Op_Address |
| (T : Tag; |
| Position : Positive; |
| Value : System.Address); |
| -- Given a pointer to a dispatch Table (T) and a position in the dispatch |
| -- Table put the address of the virtual function in it (used for |
| -- overriding). |
| |
| procedure Set_Prim_Op_Kind |
| (T : Tag; |
| Position : Positive; |
| Value : Prim_Op_Kind); |
| -- Set the kind of a primitive operation in T's TSD table indexed by |
| -- Position. |
| |
| procedure Set_RC_Offset (T : Tag; Value : SSE.Storage_Offset); |
| -- Sets the Offset of the implicit record controller when the object |
| -- has controlled components. Set to O otherwise. |
| |
| procedure Set_Remotely_Callable (T : Tag; Value : Boolean); |
| -- Set to true if the type has been declared in a context described |
| -- in E.4 (18). |
| |
| procedure Set_Signature (T : Tag; Value : Signature_Kind); |
| -- Given a pointer T to a dispatch table, store the signature id |
| |
| procedure Set_SSD (T : Tag; Value : System.Address); |
| -- Given a pointer T to a dispatch Table, stores the pointer to the record |
| -- containing the Select Specific Data generated by GNAT. |
| |
| procedure Set_Tagged_Kind (T : Tag; Value : Tagged_Kind); |
| -- Set the tagged kind of a type in either a primary or a secondary |
| -- dispatch table denoted by T. |
| |
| procedure Set_TSD (T : Tag; Value : System.Address); |
| -- Given a pointer T to a dispatch Table, stores the address of the record |
| -- containing the Type Specific Data generated by GNAT. |
| |
| function SSD (T : Tag) return Select_Specific_Data_Ptr; |
| -- Given a pointer T to a dispatch Table, retrieves the address of the |
| -- record containing the Select Specific Data in T's TSD. |
| |
| function TSD (T : Tag) return Type_Specific_Data_Ptr; |
| -- Given a pointer T to a dispatch Table, retrieves the address of the |
| -- record containing the Type Specific Data generated by GNAT. |
| |
| DT_Prologue_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| ((Default_Prim_Op_Count + 4) * |
| (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of the hidden part of the dispatch table. It contains the table of |
| -- predefined primitive operations plus the C++ ABI header. |
| |
| DT_Signature_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (1 * (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of the Signature field of the dispatch table |
| |
| DT_Tagged_Kind_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count (1 * (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of the Tagged_Type_Kind field of the dispatch table |
| |
| DT_Offset_To_Top_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (1 * (Standard'Address_Size / |
| System.Storage_Unit)); |
| -- Size of the Offset_To_Top field of the Dispatch Table |
| |
| DT_Typeinfo_Ptr_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (1 * (Standard'Address_Size / |
| System.Storage_Unit)); |
| -- Size of the Typeinfo_Ptr field of the Dispatch Table |
| |
| DT_Entry_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (1 * (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of each primitive operation entry in the Dispatch Table |
| |
| Tag_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count (1 * (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of each tag |
| |
| TSD_Prologue_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (10 * (Standard'Address_Size / |
| System.Storage_Unit)); |
| -- Size of the first part of the type specific data |
| |
| TSD_Entry_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count |
| (1 * (Standard'Address_Size / System.Storage_Unit)); |
| -- Size of each ancestor tag entry in the TSD |
| |
| type Address_Array is array (Natural range <>) of System.Address; |
| pragma Suppress (Index_Check, On => Address_Array); |
| -- The reason we suppress index checks is that in the body, objects |
| -- of this type are declared with a dummy size of 1, the actual size |
| -- depending on the number of primitive operations. |
| |
| -- Unchecked Conversions |
| |
| type Addr_Ptr is access System.Address; |
| type Tag_Ptr is access Tag; |
| |
| type Signature_Values is |
| array (1 .. DT_Signature_Size) of Signature_Kind; |
| -- Type used to see the signature as a sequence of Signature_Kind values |
| |
| type Signature_Values_Ptr is access all Signature_Values; |
| |
| function To_Addr_Ptr is |
| new Unchecked_Conversion (System.Address, Addr_Ptr); |
| |
| function To_Type_Specific_Data_Ptr is |
| new Unchecked_Conversion (System.Address, Type_Specific_Data_Ptr); |
| |
| function To_Address is |
| new Unchecked_Conversion (Interface_Tag, System.Address); |
| |
| function To_Address is |
| new Unchecked_Conversion (Tag, System.Address); |
| |
| function To_Address is |
| new Unchecked_Conversion (Type_Specific_Data_Ptr, System.Address); |
| |
| function To_Interface_Data_Ptr is |
| new Unchecked_Conversion (System.Address, Interface_Data_Ptr); |
| |
| function To_Object_Specific_Data_Ptr is |
| new Unchecked_Conversion (System.Address, Object_Specific_Data_Ptr); |
| |
| function To_Select_Specific_Data_Ptr is |
| new Unchecked_Conversion (System.Address, Select_Specific_Data_Ptr); |
| |
| function To_Signature_Values is |
| new Unchecked_Conversion (System.Storage_Elements.Storage_Offset, |
| Signature_Values); |
| |
| function To_Signature_Values_Ptr is |
| new Unchecked_Conversion (System.Address, |
| Signature_Values_Ptr); |
| |
| function To_Tag is |
| new Unchecked_Conversion (System.Address, Tag); |
| |
| function To_Tag_Ptr is |
| new Unchecked_Conversion (System.Address, Tag_Ptr); |
| |
| function To_Tagged_Kind_Ptr is |
| new Unchecked_Conversion (System.Address, Tagged_Kind_Ptr); |
| |
| -- Primitive dispatching operations are always inlined, to facilitate |
| -- use in a minimal/no run-time environment for high integrity use. |
| |
| pragma Inline_Always (CW_Membership); |
| pragma Inline_Always (Displace); |
| pragma Inline_Always (IW_Membership); |
| pragma Inline_Always (Get_Access_Level); |
| pragma Inline_Always (Get_Entry_Index); |
| pragma Inline_Always (Get_Offset_Index); |
| pragma Inline_Always (Get_Predefined_Prim_Op_Address); |
| pragma Inline_Always (Get_Prim_Op_Address); |
| pragma Inline_Always (Get_Prim_Op_Kind); |
| pragma Inline_Always (Get_RC_Offset); |
| pragma Inline_Always (Get_Remotely_Callable); |
| pragma Inline_Always (Get_Tagged_Kind); |
| pragma Inline_Always (Inherit_DT); |
| pragma Inline_Always (Inherit_TSD); |
| pragma Inline_Always (OSD); |
| pragma Inline_Always (Register_Interface_Tag); |
| pragma Inline_Always (Register_Tag); |
| pragma Inline_Always (Set_Access_Level); |
| pragma Inline_Always (Set_Entry_Index); |
| pragma Inline_Always (Set_Expanded_Name); |
| pragma Inline_Always (Set_External_Tag); |
| pragma Inline_Always (Set_Interface_Table); |
| pragma Inline_Always (Set_Num_Prim_Ops); |
| pragma Inline_Always (Set_Offset_Index); |
| pragma Inline_Always (Set_Offset_To_Top); |
| pragma Inline_Always (Set_Predefined_Prim_Op_Address); |
| pragma Inline_Always (Set_Prim_Op_Address); |
| pragma Inline_Always (Set_Prim_Op_Kind); |
| pragma Inline_Always (Set_RC_Offset); |
| pragma Inline_Always (Set_Remotely_Callable); |
| pragma Inline_Always (Set_Signature); |
| pragma Inline_Always (Set_OSD); |
| pragma Inline_Always (Set_SSD); |
| pragma Inline_Always (Set_TSD); |
| pragma Inline_Always (Set_Tagged_Kind); |
| pragma Inline_Always (SSD); |
| pragma Inline_Always (TSD); |
| |
| end Ada.Tags; |
