-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2010, 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 --
-- --
-- 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- --
+-- ware Foundation; either version 3, 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. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- 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. --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
-- --
-- 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;
function Interface_Ancestor_Tags (T : Tag) return Tag_Array;
pragma Ada_05 (Interface_Ancestor_Tags);
+ function Type_Is_Abstract (T : Tag) return Boolean;
+ pragma Ada_2012 (Type_Is_Abstract);
+
Tag_Error : exception;
private
-- Structure of the GNAT Primary Dispatch Table
-- +--------------------+
- -- | table of |
- -- :predefined primitive:
- -- | ops pointers |
- -- +--------------------+
-- | Signature |
-- +--------------------+
-- | Tagged_Kind |
- -- +--------------------+
- -- | Offset_To_Top |
- -- +--------------------+
- -- |Typeinfo_Ptr/TSD_Ptr---> Type Specific Data
+ -- +--------------------+ Predef Prims
+ -- | Predef_Prims -----------------------------> +------------+
+ -- +--------------------+ | table of |
+ -- | Offset_To_Top | | predefined |
+ -- +--------------------+ | primitives |
+ -- |Typeinfo_Ptr/TSD_Ptr---> Type Specific Data +------------+
-- Tag ---> +--------------------+ +-------------------+
-- | table of | | inheritance depth |
-- : primitive ops : +-------------------+
-- +-------------------+
-- | hash table link |
-- +-------------------+
- -- | remotely callable |
+ -- | transportable |
-- +-------------------+
- -- | rec ctrler offset |
+ -- | type_is_abstract |
-- +-------------------+
- -- | num prim ops |
+ -- | rec ctrler offset |
-- +-------------------+
- -- | Ifaces_Table_Ptr --> Interface Data
+ -- | Ifaces_Table ---> Interface Data
-- +-------------------+ +------------+
- -- Select Specific Data <---- SSD_Ptr | | table |
- -- +------------------+ +-------------------+ : of :
- -- |table of primitive| | table of | | interfaces |
- -- : operation : : ancestor : +------------+
- -- | kinds | | tags |
- -- +------------------+ +-------------------+
+ -- Select Specific Data <---- SSD | | Nb_Ifaces |
+ -- +------------------+ +-------------------+ +------------+
+ -- |table of primitive| | table of | | table |
+ -- : operation : : ancestor : : of :
+ -- | kinds | | tags | | interfaces |
+ -- +------------------+ +-------------------+ +------------+
-- |table of |
-- : entry :
- -- | indices |
+ -- | indexes |
-- +------------------+
-- Structure of the GNAT Secondary Dispatch Table
- -- +-----------------------+
- -- | table of |
- -- : predefined primitive :
- -- | ops pointers |
- -- +-----------------------+
- -- | Signature |
- -- +-----------------------+
- -- | Tagged_Kind |
- -- +-----------------------+
- -- | Offset_To_Top |
- -- +-----------------------+
- -- | OSD_Ptr |---> Object Specific Data
- -- Tag ---> +-----------------------+ +---------------+
- -- | table of | | num prim ops |
- -- : primitive op : +---------------+
- -- | thunk pointers | | table of |
- -- +-----------------------+ + primitive |
- -- | op offsets |
- -- +---------------+
+ -- +--------------------+
+ -- | Signature |
+ -- +--------------------+
+ -- | Tagged_Kind |
+ -- +--------------------+ Predef Prims
+ -- | Predef_Prims -----------------------------> +------------+
+ -- +--------------------+ | table of |
+ -- | Offset_To_Top | | predefined |
+ -- +--------------------+ | primitives |
+ -- | OSD_Ptr |---> Object Specific Data | thunks |
+ -- Tag ---> +--------------------+ +---------------+ +------------+
+ -- | table of | | num prim ops |
+ -- : primitive op : +---------------+
+ -- | thunk pointers | | table of |
+ -- +--------------------+ + primitive |
+ -- | op offsets |
+ -- +---------------+
-- 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
-
- -- where Nb_prim is the number of primitive operations of the given
- -- type and Idepth its inheritance depth.
-
- 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 dispatch table,
- -- the component of this type is declared with a dummy size of 1, the
- -- actual size depending on the number of primitive operations.
-
- type Dispatch_Table is record
-
- -- According to the C++ ABI the components Offset_To_Top and
- -- Typeinfo_Ptr are stored just "before" the dispatch table (that is,
- -- the Prims_Ptr table), and they are referenced with negative offsets
- -- referring to the base of the dispatch table. The _Tag (or the
- -- VTable_Ptr in C++ terminology) must point to the base of the virtual
- -- table, just after these components, to point to the Prims_Ptr table.
- -- For this purpose the expander generates a Prims_Ptr table that has
- -- enough space for these additional components, and generates code that
- -- displaces the _Tag to point after these components.
-
- -- Signature : Signature_Kind;
- -- Tagged_Kind : Tagged_Kind;
- -- Offset_To_Top : Natural;
- -- Typeinfo_Ptr : System.Address;
-
- Prims_Ptr : Address_Array (1 .. 1);
- -- The size of the Prims_Ptr array actually depends on the tagged type
- -- to which it applies. For each tagged type, the expander computes the
- -- actual array size, allocates the Dispatch_Table record accordingly,
- -- and generates code that displaces the base of the record after the
- -- Typeinfo_Ptr component. For this reason the first two components have
- -- been commented in the previous declaration. The access to these
- -- components is done by means of local functions.
- --
- -- To avoid the use of discriminants to define the actual size of the
- -- dispatch table, we used to declare the tag as a pointer to a record
- -- that contains an arbitrary array of addresses, using Positive as its
- -- index. This ensures that there are never range checks when accessing
- -- the dispatch table, but it prevents GDB from displaying tagged types
- -- properly. A better approach is to declare this record type as holding
- -- small number of addresses, and to explicitly suppress checks on it.
- --
- -- Note that in both cases, this type is never allocated, and serves
- -- only to declare the corresponding access type.
- end record;
+ -- objects: the Dispatch Table and the Type Specific Data record.
+
+ package SSE renames System.Storage_Elements;
subtype Cstring is String (Positive);
type Cstring_Ptr is access all Cstring;
pragma No_Strict_Aliasing (Cstring_Ptr);
- -- We suppress index checks because the declared size in the record below
- -- is a dummy size of one (see below).
+ -- Declarations for the table of interfaces
- type Tag_Table is array (Natural range <>) of Tag;
- pragma Suppress_Initialization (Tag_Table);
- pragma Suppress (Index_Check, On => Tag_Table);
+ type Offset_To_Top_Function_Ptr is
+ access function (This : System.Address) return SSE.Storage_Offset;
+ -- Type definition used to call the function that is generated by the
+ -- expander in case of tagged types with discriminants that have secondary
+ -- dispatch tables. This function provides the Offset_To_Top value in this
+ -- specific case.
- package SSE renames System.Storage_Elements;
+ type Interface_Data_Element is record
+ Iface_Tag : Tag;
+ Static_Offset_To_Top : Boolean;
+ Offset_To_Top_Value : SSE.Storage_Offset;
+ Offset_To_Top_Func : Offset_To_Top_Function_Ptr;
+ Secondary_DT : Tag;
+ end record;
+ -- If some ancestor of the tagged type has discriminants the field
+ -- Static_Offset_To_Top is False and the field Offset_To_Top_Func
+ -- is used to store the access to the function generated by the
+ -- expander which provides this value; otherwise Static_Offset_To_Top
+ -- is True and such value is stored in the Offset_To_Top_Value field.
+ -- Secondary_DT references a secondary dispatch table whose contents
+ -- are pointers to the primitives of the tagged type that cover the
+ -- interface primitives. Secondary_DT gives support to dispatching
+ -- calls through interface types associated with Generic Dispatching
+ -- Constructors.
+
+ type Interfaces_Array is array (Natural range <>) of Interface_Data_Element;
+
+ type Interface_Data (Nb_Ifaces : Positive) is record
+ Ifaces_Table : Interfaces_Array (1 .. Nb_Ifaces);
+ end record;
+
+ 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.
+
+ -- 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);
+
+ -- Select specific data types
+
+ type Select_Specific_Data_Element is record
+ Index : Positive;
+ Kind : Prim_Op_Kind;
+ end record;
+
+ type Select_Specific_Data_Array is
+ array (Positive range <>) of Select_Specific_Data_Element;
+
+ type Select_Specific_Data (Nb_Prim : Positive) is record
+ SSD_Table : Select_Specific_Data_Array (1 .. Nb_Prim);
+ -- NOTE: Nb_Prim is the number of non-predefined primitive operations
+ end record;
+
+ 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 Prim_Ptr is access procedure;
+ type Address_Array is array (Positive range <>) of Prim_Ptr;
+
+ subtype Dispatch_Table is Address_Array (1 .. 1);
+ -- Used by GDB to identify the _tags and traverse the run-time structure
+ -- associated with tagged types. For compatibility with older versions of
+ -- gdb, its name must not be changed.
+
+ type Tag is access all Dispatch_Table;
+ pragma No_Strict_Aliasing (Tag);
+
+ type Interface_Tag is access all Dispatch_Table;
+
+ No_Tag : constant Tag := null;
+
+ -- The expander ensures that Tag objects reference the Prims_Ptr component
+ -- of the wrapper.
- -- Type specific data types
+ type Tag_Ptr is access all Tag;
+ pragma No_Strict_Aliasing (Tag_Ptr);
+
+ type Offset_To_Top_Ptr is access all SSE.Storage_Offset;
+ pragma No_Strict_Aliasing (Offset_To_Top_Ptr);
+
+ type Tag_Table is array (Natural range <>) of Tag;
+
+ type Size_Ptr is
+ access function (A : System.Address) return Long_Long_Integer;
type Type_Specific_Data (Idepth : Natural) is record
- -- Inheritance Depth Level: Used to implement the membership test
- -- associated with single inheritance of tagged types in constant-time.
- -- It also indicates the size of the Tags_Table component.
+ -- The discriminant Idepth is the Inheritance Depth Level: Used to
+ -- implement the membership test associated with single inheritance of
+ -- tagged types in constant-time. It also indicates the size of the
+ -- Tags_Table component.
Access_Level : Natural;
-- Accessibility level required to give support to Ada 2005 nested type
Expanded_Name : Cstring_Ptr;
External_Tag : Cstring_Ptr;
- HT_Link : Tag;
- -- Components used to support to the Ada.Tags subprograms in RM 3.9.
- -- Note: Expanded_Name is referenced by GDB ???
+ HT_Link : Tag_Ptr;
+ -- Components used to support to the Ada.Tags subprograms in RM 3.9
+
+ -- Note: Expanded_Name is referenced by GDB to determine the actual name
+ -- of the tagged type. Its requirements are: 1) it must have this exact
+ -- name, and 2) its contents must point to a C-style Nul terminated
+ -- string containing its expanded name. GDB has no requirement on a
+ -- given position inside the record.
- Remotely_Callable : Boolean;
- -- Used to check ARM E.4 (18)
+ Transportable : Boolean;
+ -- Used to check RM E.4(18), set for types that satisfy the requirements
+ -- for being used in remote calls as actuals for classwide formals or as
+ -- return values for classwide functions.
+
+ Type_Is_Abstract : Boolean;
+ -- True if the type is abstract (Ada 2012: AI05-0173)
RC_Offset : SSE.Storage_Offset;
-- Controller Offset: Used to give support to tagged controlled objects
-- (see Get_Deep_Controller at s-finimp)
- Ifaces_Table_Ptr : System.Address;
+ Size_Func : Size_Ptr;
+ -- Pointer to the subprogram computing the _size of the object. Used by
+ -- the run-time whenever a call to the 'size primitive is required. We
+ -- cannot assume that the contents of dispatch tables are addresses
+ -- because in some architectures the ABI allows descriptors.
+
+ Interfaces_Table : Interface_Data_Ptr;
-- Pointer to the table of interface tags. It is used to implement the
-- membership test associated with interfaces and also for backward
-- abstract interface type conversions (Ada 2005:AI-251)
- SSD_Ptr : System.Address;
+ SSD : Select_Specific_Data_Ptr;
-- Pointer to a table of records used in dispatching selects. This
-- field has a meaningful value for all tagged types that implement
-- a limited, protected, synchronized or task interfaces and have
-- depth level of the tagged type.
end record;
- -- Declarations for the table of interfaces
-
- type Interface_Data_Element is record
- Iface_Tag : Tag;
- Static_Offset_To_Top : Boolean;
- Offset_To_Top_Value : System.Storage_Elements.Storage_Offset;
- Offset_To_Top_Func : System.Address;
- end record;
- -- If some ancestor of the tagged type has discriminants the field
- -- Static_Offset_To_Top is False and the field Offset_To_Top_Func
- -- is used to store the address of the function generated by the
- -- expander which provides this value; otherwise Static_Offset_To_Top
- -- is True and such value is stored in the Offset_To_Top_Value field.
-
- type Interfaces_Array is
- array (Natural range <>) of Interface_Data_Element;
-
- type Interface_Data (Nb_Ifaces : Positive) is record
- Ifaces_Table : Interfaces_Array (1 .. Nb_Ifaces);
- end record;
-
- -- Declaration of tag types
-
- type Tag is access all Dispatch_Table;
- type Tag_Ptr is access Tag;
- type Interface_Tag is access all Dispatch_Table;
type Type_Specific_Data_Ptr is access all Type_Specific_Data;
+ pragma No_Strict_Aliasing (Type_Specific_Data_Ptr);
- No_Tag : constant Tag := null;
-
- 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.
-
- -- 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.
+ -- Declarations for the dispatch table record
- 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);
+ type Signature_Kind is
+ (Unknown,
+ Primary_DT,
+ Secondary_DT);
-- Tagged type kinds with respect to concurrency and limitedness
TK_Tagged,
TK_Task);
- type Tagged_Kind_Ptr is access all Tagged_Kind;
+ type Dispatch_Table_Wrapper (Num_Prims : Natural) is record
+ Signature : Signature_Kind;
+ Tag_Kind : Tagged_Kind;
+ Predef_Prims : System.Address;
+ -- Pointer to the dispatch table of predefined Ada primitives
- Default_Prim_Op_Count : constant Positive := 15;
- -- Maximum number of predefined primitive operations of a tagged type.
+ -- According to the C++ ABI the components Offset_To_Top and TSD are
+ -- stored just "before" the dispatch table, and they are referenced with
+ -- negative offsets referring to the base of the dispatch table. The
+ -- _Tag (or the VTable_Ptr in C++ terminology) must point to the base
+ -- of the virtual table, just after these components, to point to the
+ -- Prims_Ptr table.
- 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.
-
- DT_Min_Prologue_Size : constant SSE.Storage_Count :=
+ Offset_To_Top : SSE.Storage_Offset;
+ TSD : System.Address;
+
+ Prims_Ptr : aliased Address_Array (1 .. Num_Prims);
+ -- The size of the Prims_Ptr array actually depends on the tagged type
+ -- to which it applies. For each tagged type, the expander computes the
+ -- actual array size, allocates the Dispatch_Table record accordingly.
+ end record;
+
+ type Dispatch_Table_Ptr is access all Dispatch_Table_Wrapper;
+ pragma No_Strict_Aliasing (Dispatch_Table_Ptr);
+
+ -- The following type declaration is used by the compiler when the program
+ -- is compiled with restriction No_Dispatching_Calls. It is also used with
+ -- interface types to generate the tag and run-time information associated
+ -- with them.
+
+ type No_Dispatch_Table_Wrapper is record
+ NDT_TSD : System.Address;
+ NDT_Prims_Ptr : Natural;
+ end record;
+
+ DT_Predef_Prims_Size : constant SSE.Storage_Count :=
SSE.Storage_Count
- (2 * (Standard'Address_Size /
+ (1 * (Standard'Address_Size /
System.Storage_Unit));
- -- Size of the hidden part of the dispatch table used when the program
- -- is compiled under restriction No_Dispatching_Calls. It contains the
- -- pointer to the TSD record plus a dummy entry whose address is used
- -- at run-time as the Tag.
-
- 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
+ -- Size of the Predef_Prims field of the Dispatch_Table
DT_Offset_To_Top_Size : constant SSE.Storage_Count :=
SSE.Storage_Count
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
-
- -- Constants used by the code generated by the frontend to get access
- -- to the header of the dispatch table.
-
- K_Typeinfo : constant SSE.Storage_Count := DT_Typeinfo_Ptr_Size;
- K_Offset_To_Top : constant SSE.Storage_Count :=
- System.Storage_Elements."+"
- (K_Typeinfo, DT_Offset_To_Top_Size);
- K_Tagged_Kind : constant SSE.Storage_Count :=
- System.Storage_Elements."+"
- (K_Offset_To_Top, DT_Tagged_Kind_Size);
- K_Signature : constant SSE.Storage_Count :=
- System.Storage_Elements."+"
- (K_Tagged_Kind, DT_Signature_Size);
+ use type System.Storage_Elements.Storage_Offset;
+
+ DT_Offset_To_Top_Offset : constant SSE.Storage_Count :=
+ DT_Typeinfo_Ptr_Size
+ + DT_Offset_To_Top_Size;
+
+ DT_Predef_Prims_Offset : constant SSE.Storage_Count :=
+ DT_Typeinfo_Ptr_Size
+ + DT_Offset_To_Top_Size
+ + DT_Predef_Prims_Size;
+ -- Offset from Prims_Ptr to Predef_Prims component
+
+ -- Object Specific Data record of secondary dispatch tables
+
+ type Object_Specific_Data_Array is array (Positive range <>) of Positive;
+
+ type Object_Specific_Data (OSD_Num_Prims : Positive) is record
+ OSD_Table : Object_Specific_Data_Array (1 .. OSD_Num_Prims);
+ -- Table used in secondary DT to reference their counterpart in the
+ -- select specific data (in the TSD of the primary DT). This construct
+ -- is used in the handling of dispatching triggers in select statements.
+ -- Nb_Prim is the number of non-predefined primitive operations.
+ end record;
+
+ type Object_Specific_Data_Ptr is access all Object_Specific_Data;
+ pragma No_Strict_Aliasing (Object_Specific_Data_Ptr);
-- The following subprogram specifications are placed here instead of
-- the package body to see them from the frontend through rtsfind.
-- Ada 2005 (AI-251): Displace "This" to point to the base address of
-- the object (that is, the address of the primary tag of the object).
- 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 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 Secondary_Tag (T, Iface : Tag) return Tag;
+ -- Ada 2005 (AI-251): Given a primary tag T associated with a tagged type
+ -- Typ, search for the secondary tag of the interface type Iface covered
+ -- by Typ.
+
+ function DT (T : Tag) return Dispatch_Table_Ptr;
+ -- Return the pointer to the TSD record associated with T
+
function Get_Entry_Index (T : Tag; Position : Positive) return Positive;
-- Ada 2005 (AI-251): 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;
- -- Returns address of a null terminated string containing the external name
-
function Get_Offset_Index
(T : Tag;
Position : Positive) return Positive;
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.
+ -- has controlled components, returns zero if no controlled components.
pragma Export (Ada, Get_RC_Offset, "ada__tags__get_rc_offset");
-- This procedure is used in s-finimp to compute the deep routines
-- end Test;
function Offset_To_Top
- (This : System.Address) return System.Storage_Elements.Storage_Offset;
+ (This : System.Address) return SSE.Storage_Offset;
-- Ada 2005 (AI-251): 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 Object Specific
- -- Data table.
-
function Parent_Size
(Obj : System.Address;
T : Tag) return SSE.Storage_Count;
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_Interface_Offset
+ (This : System.Address;
+ Interface_T : Tag;
+ Is_Static : Boolean;
+ Offset_Value : SSE.Storage_Offset;
+ Offset_Func : Offset_To_Top_Function_Ptr);
+ -- Register in the table of interfaces of the tagged type associated with
+ -- "This" object the offset of the record component associated with the
+ -- progenitor Interface_T (that is, the distance from "This" to the object
+ -- component containing the tag of the secondary dispatch table). In case
+ -- of constant offset, Is_Static is true and Offset_Value has such value.
+ -- In case of variable offset, Is_Static is false and Offset_Func is an
+ -- access to function that must be called to evaluate the offset.
procedure Register_Tag (T : Tag);
-- Insert the Tag and its associated external_tag in a table for the
-- sake of Internal_Tag
+ procedure Set_Dynamic_Offset_To_Top
+ (This : System.Address;
+ Interface_T : Tag;
+ Offset_Value : SSE.Storage_Offset;
+ Offset_Func : Offset_To_Top_Function_Ptr);
+ -- Ada 2005 (AI-251): The compiler generates calls to this routine only
+ -- when initializing the Offset_To_Top field of dispatch tables associated
+ -- with tagged type whose parent has variable size components. "This" is
+ -- the object whose dispatch table is being initialized. 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 (a zero value means
+ -- that this interface shares the primary dispatch table). Offset_Func
+ -- references a function that must be called to evaluate the offset at
+ -- runtime. This routine also takes care of registering these values in
+ -- the table of interfaces of the type.
+
procedure Set_Entry_Index (T : Tag; Position : Positive; Value : Positive);
-- Ada 2005 (AI-345): Set the entry index of a primitive operation in T's
-- TSD table indexed by Position.
- 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_Offset_Index
- (T : Tag;
- Position : Positive;
- Value : Positive);
- -- Ada 2005 (AI-345): 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);
- -- Ada 2005 (AI-251): 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_Prim_Op_Kind
(T : Tag;
Position : Positive;
-- Ada 2005 (AI-251): Set the kind of a primitive operation in T's TSD
-- table indexed by Position.
- 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);
- -- Ada 2005 (AI-345): 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);
- -- Ada 2005 (AI-345): Set the tagged kind of a type in either a primary or
- -- a secondary dispatch table denoted by T.
-
- function SSD (T : Tag) return Select_Specific_Data_Ptr;
- -- Ada 2005 (AI-251): 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.
+ Max_Predef_Prims : constant Positive := 16;
+ -- Number of reserved slots for the following predefined ada primitives:
+ --
+ -- 1. Size
+ -- 2. Alignment,
+ -- 3. Read
+ -- 4. Write
+ -- 5. Input
+ -- 6. Output
+ -- 7. "="
+ -- 8. assignment
+ -- 9. deep adjust
+ -- 10. deep finalize
+ -- 11. async select
+ -- 12. conditional select
+ -- 13. prim_op kind
+ -- 14. task_id
+ -- 15. dispatching requeue
+ -- 16. timed select
+ --
+ -- The compiler checks that the value here is correct
- -- Unchecked Conversions
+ subtype Predef_Prims_Table is Address_Array (1 .. Max_Predef_Prims);
+ type Predef_Prims_Table_Ptr is access Predef_Prims_Table;
+ pragma No_Strict_Aliasing (Predef_Prims_Table_Ptr);
type Addr_Ptr is access System.Address;
-
- 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 (Tag, 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_Entry_Index);
- pragma Inline_Always (Get_Offset_Index);
- pragma Inline_Always (Get_Prim_Op_Kind);
- pragma Inline_Always (Get_Tagged_Kind);
- pragma Inline_Always (OSD);
- pragma Inline_Always (Register_Interface_Tag);
- pragma Inline_Always (Register_Tag);
- pragma Inline_Always (Set_Entry_Index);
- pragma Inline_Always (Set_Interface_Table);
- pragma Inline_Always (Set_Offset_Index);
- pragma Inline_Always (Set_Offset_To_Top);
- pragma Inline_Always (Set_Prim_Op_Kind);
- pragma Inline_Always (Set_Signature);
- pragma Inline_Always (Set_OSD);
- pragma Inline_Always (Set_SSD);
- pragma Inline_Always (Set_Tagged_Kind);
- pragma Inline_Always (SSD);
- pragma Inline_Always (TSD);
+ pragma No_Strict_Aliasing (Addr_Ptr);
+ -- This type is used by the frontend to generate the code that handles
+ -- dispatch table slots of types declared at the local level.
end Ada.Tags;
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