-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2007, 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 --
with System;
with System.Storage_Elements;
-with Unchecked_Conversion;
package Ada.Tags is
pragma Preelaborate_05;
Tag_Error : exception;
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
+ -- Structure of the GNAT Primary Dispatch Table
+
+ -- +--------------------+
+ -- | Signature |
+ -- +--------------------+
+ -- | Tagged_Kind |
+ -- +--------------------+ 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 : +-------------------+
+ -- | pointers | | access level |
+ -- +--------------------+ +-------------------+
+ -- | expanded name |
+ -- +-------------------+
+ -- | external tag |
+ -- +-------------------+
+ -- | hash table link |
+ -- +-------------------+
+ -- | remotely callable |
+ -- +-------------------+
+ -- | rec ctrler offset |
+ -- +-------------------+
+ -- | Ifaces_Table ---> Interface Data
+ -- +-------------------+ +------------+
+ -- Select Specific Data <---- SSD | | Nb_Ifaces |
+ -- +------------------+ +-------------------+ +------------+
+ -- |table of primitive| | table of | | table |
+ -- : operation : : ancestor : : of :
+ -- | kinds | | tags | | interfaces |
+ -- +------------------+ +-------------------+ +------------+
+ -- |table of |
+ -- : entry :
+ -- | indices |
+ -- +------------------+
+
+ -- 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 |
+ -- +---------------+
+
+ -- The runtime information kept for each tagged type is separated into two
+ -- objects: the Dispatch Table and the Type Specific Data record.
- -- 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;
+ package SSE renames System.Storage_Elements;
- No_Tag : constant Tag := null;
+ subtype Cstring is String (Positive);
+ type Cstring_Ptr is access all Cstring;
+ pragma No_Strict_Aliasing (Cstring_Ptr);
+
+ -- Declarations for the table of interfaces
+
+ 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.
+
+ 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;
+ 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.
+
+ 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 (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.
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 Address_Array is array (Positive range <>) of System.Address;
+
+ 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 Tag_Ptr is access all Tag;
+ pragma No_Strict_Aliasing (Tag_Ptr);
+
+ type Tag_Table is array (Natural range <>) of Tag;
+
+ type Type_Specific_Data (Idepth : Natural) is record
+ -- 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
+ -- extensions. This feature allows safe nested type extensions by
+ -- shifting the accessibility checks to certain operations, rather than
+ -- being enforced at the type declaration. In particular, by performing
+ -- run-time accessibility checks on class-wide allocators, class-wide
+ -- function return, and class-wide stream I/O, the danger of objects
+ -- outliving their type declaration can be eliminated (Ada 2005: AI-344)
+
+ Expanded_Name : Cstring_Ptr;
+ External_Tag : Cstring_Ptr;
+ 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.
+
+ 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.
+
+ RC_Offset : SSE.Storage_Offset;
+ -- Controller Offset: Used to give support to tagged controlled objects
+ -- (see Get_Deep_Controller at s-finimp)
+
+ 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 : 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
+ -- non-predefined primitive operations.
+
+ Tags_Table : Tag_Table (0 .. Idepth);
+ -- Table of ancestor tags. Its size actually depends on the inheritance
+ -- depth level of the tagged type.
+ end record;
+
+ type Type_Specific_Data_Ptr is access all Type_Specific_Data;
+ pragma No_Strict_Aliasing (Type_Specific_Data_Ptr);
+
+ -- Declarations for the dispatch table record
+
+ type Signature_Kind is
+ (Unknown,
+ Primary_DT,
+ Secondary_DT);
+
-- Tagged type kinds with respect to concurrency and limitedness
type Tagged_Kind is
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
+
+ -- 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.
+
+ 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
+ (1 * (Standard'Address_Size /
+ System.Storage_Unit));
+ -- Size of the Predef_Prims field of the Dispatch_Table
- 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).
+ 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
- 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_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
- package SSE renames System.Storage_Elements;
+ use type System.Storage_Elements.Storage_Offset;
- 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.
+ 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
- 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 : I'Class) is
- -- begin
- -- return O in T'Class.
- -- end Test;
+ -- 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.
+
+ function Base_Address (This : System.Address) return System.Address;
+ -- 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 Displace (This : System.Address; T : Tag) return System.Address;
- -- (Ada 2005 (AI-251): Displace "This" to point to the secondary dispatch
+ -- 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 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;
- -- 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.
+ -- 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_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).
+ -- Ada 2005 (AI-251): 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_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.
+ -- Ada 2005 (AI-251): 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.
+ -- 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
-- 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_CPP_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 CPP ancestor and the number of primitive ops that
- -- are inherited (Entry_Count).
+ -- Ada 2005 (AI-345): 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 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 : I'Class) is
+ -- begin
+ -- return O in T'Class.
+ -- end Test;
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.
+ (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 Parent_Size
(Obj : System.Address;
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.
+ -- Ada 2005 (AI-345): Set the entry index of a primitive operation in T's
+ -- TSD table 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);
+ Offset_Value : SSE.Storage_Offset;
+ Offset_Func : Offset_To_Top_Function_Ptr);
-- 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
-- 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.
+ -- Ada 2005 (AI-251): Set the kind of a primitive operation in T's TSD
+ -- table indexed by Position.
- 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
+ Max_Predef_Prims : constant Positive := 15;
+ -- Number of reserved slots for predefined ada primitives: Size, Alignment,
+ -- Read, Write, Input, Output, "=", assignment, deep adjust, deep finalize,
+ -- async select, conditional select, prim_op kind, task_id, and timed
+ -- select. The compiler checks that this value is correct.
- 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
+ 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 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);
-
+ pragma No_Strict_Aliasing (Addr_Ptr);
end Ada.Tags;
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