| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ D I S P -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- |
| -- -- |
| -- 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. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package contains routines involved in tagged types and dynamic |
| -- dispatching expansion. |
| |
| with Types; use Types; |
| |
| package Exp_Disp is |
| |
| ------------------------------------- |
| -- Predefined primitive operations -- |
| ------------------------------------- |
| |
| -- The predefined primitive operations (PPOs) are subprograms generated |
| -- by GNAT for a particular tagged type. Their role is to provide support |
| -- for different Ada language features such as the attribute 'Size or |
| -- handling of dispatching triggers in select statements. PPOs are created |
| -- when a tagged type is expanded or frozen. These subprograms are later |
| -- collected and inserted into the dispatch table of a tagged type at |
| -- fixed positions. Some of the PPOs that manipulate data in tagged objects |
| -- require the generation of thunks. |
| |
| -- List of predefined primitive operations |
| |
| -- Leading underscores designate reserved names. Bracketed numerical |
| -- values represent dispatch table slot numbers. |
| |
| -- _Size (1) - implementation of the attribute 'Size for any tagged |
| -- type. Constructs of the form Prefix'Size are converted into |
| -- Prefix._Size. |
| |
| -- _Alignment (2) - implementation of the attribute 'Alignment for |
| -- any tagged type. Constructs of the form Prefix'Alignment are |
| -- converted into Prefix._Alignment. |
| |
| -- TSS_Stream_Read (3) - implementation of the stream attribute Read |
| -- for any tagged type. |
| |
| -- TSS_Stream_Write (4) - implementation of the stream attribute Write |
| -- for any tagged type. |
| |
| -- TSS_Stream_Input (5) - implementation of the stream attribute Input |
| -- for any tagged type. |
| |
| -- TSS_Stream_Output (6) - implementation of the stream attribute |
| -- Output for any tagged type. |
| |
| -- Op_Eq (7) - implementation of the equality operator for any non- |
| -- limited tagged type. |
| |
| -- _Assign (8) - implementation of the assignment operator for any |
| -- non-limited tagged type. |
| |
| -- TSS_Deep_Adjust (9) - implementation of the finalization operation |
| -- Adjust for any non-limited tagged type. |
| |
| -- TSS_Deep_Finalize (10) - implementation of the finalization |
| -- operation Finalize for any non-limited tagged type. |
| |
| -- _Disp_Asynchronous_Select (11) - used in the expansion of ATC with |
| -- dispatching triggers. Null implementation for limited interfaces, |
| -- full body generation for types that implement limited interfaces, |
| -- not generated for the rest of the cases. See Expand_N_Asynchronous_ |
| -- Select in Exp_Ch9 for more information. |
| |
| -- _Disp_Conditional_Select (12) - used in the expansion of conditional |
| -- selects with dispatching triggers. Null implementation for limited |
| -- interfaces, full body generation for types that implement limited |
| -- interfaces, not generated for the rest of the cases. See Expand_N_ |
| -- Conditional_Entry_Call in Exp_Ch9 for more information. |
| |
| -- _Disp_Get_Prim_Op_Kind (13) - helper routine used in the expansion |
| -- of ATC with dispatching triggers. Null implementation for limited |
| -- interfaces, full body generation for types that implement limited |
| -- interfaces, not generated for the rest of the cases. |
| |
| -- _Disp_Get_Task_Id (14) - helper routine used in the expansion of |
| -- Abort, attributes 'Callable and 'Terminated for task interface |
| -- class-wide types. Full body generation for task types, null |
| -- implementation for limited interfaces, not generated for the rest |
| -- of the cases. See Expand_N_Attribute_Reference in Exp_Attr and |
| -- Expand_N_Abort_Statement in Exp_Ch9 for more information. |
| |
| -- _Disp_Timed_Select (15) - used in the expansion of timed selects |
| -- with dispatching triggers. Null implementation for limited |
| -- interfaces, full body generation for types that implement limited |
| -- interfaces, not generated for the rest of the cases. See Expand_N_ |
| -- Timed_Entry_Call for more information. |
| |
| -- Lifecycle of predefined primitive operations |
| |
| -- The specifications and bodies of the PPOs are created by |
| -- Make_Predefined_Primitive_Specs and Predefined_Primitive_Bodies |
| -- in Exp_Ch3. The generated specifications are immediately analyzed, |
| -- while the bodies are left as freeze actions to the tagged type for |
| -- which they are created. |
| |
| -- PPOs are collected and added to the Primitive_Operations list of |
| -- a type by the regular analysis mechanism. |
| |
| -- PPOs are frozen in Predefined_Primitive_Freeze in Exp_Ch3. |
| |
| -- Thunks for PPOs are created in Freeze_Subprogram in Exp_Ch6, by a |
| -- call to Register_Predefined_DT_Entry, also in Exp_Ch6. |
| |
| -- Dispatch table positions of PPOs are set in Set_All_DT_Position in |
| -- Exp_Disp. |
| |
| -- Calls to PPOs procede as regular dispatching calls. If the PPO |
| -- has a thunk, a call procedes as a regular dispatching call with |
| -- a thunk. |
| |
| -- Guidelines for addition of new predefined primitive operations |
| |
| -- Update the value of constant Default_Prim_Op_Count in A-Tags.ads |
| -- to reflect the new number of PPOs. |
| |
| -- Introduce a new predefined name for the new PPO in Snames.ads and |
| -- Snames.adb. |
| |
| -- Categorize the new PPO name as predefined by adding an entry in |
| -- Is_Predefined_Dispatching_Operation in Exp_Util.adb. |
| |
| -- Generate the specification of the new PPO in Make_Predefined_ |
| -- Primitive_Spec in Exp_Ch3.adb. The Is_Internal flag of the defining |
| -- identifier of the specification must be set to True. |
| |
| -- Generate the body of the new PPO in Predefined_Primitive_Bodies in |
| -- Exp_Ch3.adb. The Is_Internal flag of the defining identifier of the |
| -- specification must be set to True. |
| |
| -- If the new PPO requires a thunk, add an entry in Freeze_Subprogram |
| -- in Exp_Ch6.adb. |
| |
| -- When generating calls to a PPO, use Find_Prim_Op from Exp_Util.ads |
| -- to retrieve the entity of the operation directly. |
| |
| -- Number of predefined primitive operations added by the Expander |
| -- for a tagged type. If more predefined primitive operations are |
| -- added, the following items must be changed: |
| |
| -- Ada.Tags.Defailt_Prim_Op_Count - indirect use |
| -- Exp_Disp.Default_Prim_Op_Position - indirect use |
| -- Exp_Disp.Set_All_DT_Position - direct use |
| |
| type DT_Access_Action is |
| (CW_Membership, |
| IW_Membership, |
| DT_Entry_Size, |
| DT_Prologue_Size, |
| Get_Access_Level, |
| Get_Entry_Index, |
| Get_External_Tag, |
| Get_Predefined_Prim_Op_Address, |
| Get_Prim_Op_Address, |
| Get_Prim_Op_Kind, |
| Get_RC_Offset, |
| Get_Remotely_Callable, |
| Get_Tagged_Kind, |
| Inherit_DT, |
| Inherit_TSD, |
| Register_Interface_Tag, |
| Register_Tag, |
| Set_Access_Level, |
| Set_Entry_Index, |
| Set_Expanded_Name, |
| Set_External_Tag, |
| Set_Interface_Table, |
| Set_Offset_Index, |
| Set_OSD, |
| Set_Predefined_Prim_Op_Address, |
| Set_Prim_Op_Address, |
| Set_Prim_Op_Kind, |
| Set_RC_Offset, |
| Set_Remotely_Callable, |
| Set_Signature, |
| Set_SSD, |
| Set_TSD, |
| Set_Tagged_Kind, |
| TSD_Entry_Size, |
| TSD_Prologue_Size); |
| |
| procedure Expand_Dispatching_Call (Call_Node : Node_Id); |
| -- Expand the call to the operation through the dispatch table and perform |
| -- the required tag checks when appropriate. For CPP types the call is |
| -- done through the Vtable (tag checks are not relevant) |
| |
| procedure Expand_Interface_Actuals (Call_Node : Node_Id); |
| -- Ada 2005 (AI-251): Displace all the actuals corresponding to class-wide |
| -- interfaces to reference the interface tag of the actual object |
| |
| procedure Expand_Interface_Conversion |
| (N : Node_Id; |
| Is_Static : Boolean := True); |
| -- Ada 2005 (AI-251): N is a type-conversion node. Reference the base of |
| -- the object to give access to the interface tag associated with the |
| -- secondary dispatch table. |
| |
| function Expand_Interface_Thunk |
| (N : Node_Id; |
| Thunk_Alias : Node_Id; |
| Thunk_Id : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-251): When a tagged type implements abstract interfaces we |
| -- generate additional subprograms (thunks) to have a layout compatible |
| -- with the C++ ABI. The thunk modifies the value of the first actual of |
| -- the call (that is, the pointer to the object) before transferring |
| -- control to the target function. |
| |
| function Fill_DT_Entry |
| (Loc : Source_Ptr; |
| Prim : Entity_Id) return Node_Id; |
| -- Generate the code necessary to fill the appropriate entry of the |
| -- dispatch table of Prim's controlling type with Prim's address. |
| |
| function Fill_Secondary_DT_Entry |
| (Loc : Source_Ptr; |
| Prim : Entity_Id; |
| Thunk_Id : Entity_Id; |
| Iface_DT_Ptr : Entity_Id) return Node_Id; |
| -- (Ada 2005): Generate the code necessary to fill the appropriate entry of |
| -- the secondary dispatch table of Prim's controlling type with Thunk_Id's |
| -- address. |
| |
| function Get_Remotely_Callable (Obj : Node_Id) return Node_Id; |
| -- Return an expression that holds True if the object can be transmitted |
| -- onto another partition according to E.4 (18) |
| |
| function Init_Predefined_Interface_Primitives |
| (Typ : Entity_Id) return List_Id; |
| -- Ada 2005 (AI-251): Initialize the entries associated with predefined |
| -- primitives in all the secondary dispatch tables of Typ. |
| |
| function Make_DT_Access_Action |
| (Typ : Entity_Id; |
| Action : DT_Access_Action; |
| Args : List_Id) return Node_Id; |
| -- Generate a call to one of the Dispatch Table Access Subprograms defined |
| -- in Ada.Tags or in Interfaces.Cpp |
| |
| function Make_DT (Typ : Entity_Id) return List_Id; |
| -- Expand the declarations for the Dispatch Table (or the Vtable in |
| -- the case of type whose ancestor is a CPP_Class) |
| |
| function Make_Disp_Asynchronous_Select_Body |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the body of the primitive operation of type |
| -- Typ used for dispatching in asynchronous selects. Generate a null body |
| -- if Typ is an interface type. |
| |
| function Make_Disp_Asynchronous_Select_Spec |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the specification of the primitive operation |
| -- of type Typ used for dispatching in asynchronous selects. |
| |
| function Make_Disp_Conditional_Select_Body |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the body of the primitive operation of type |
| -- Typ used for dispatching in conditional selects. Generate a null body |
| -- if Typ is an interface type. |
| |
| function Make_Disp_Conditional_Select_Spec |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the specification of the primitive operation |
| -- of type Typ used for dispatching in conditional selects. |
| |
| function Make_Disp_Get_Prim_Op_Kind_Body |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the body of the primitive operation of type |
| -- Typ used for retrieving the callable entity kind during dispatching in |
| -- asynchronous selects. Generate a null body if Typ is an interface type. |
| |
| function Make_Disp_Get_Prim_Op_Kind_Spec |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the specification of the primitive operation |
| -- of the type Typ use for retrieving the callable entity kind during |
| -- dispatching in asynchronous selects. |
| |
| function Make_Disp_Get_Task_Id_Body |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the body of the primitive operation of type |
| -- Typ used for retrieving the _task_id field of a task interface class- |
| -- wide type. Generate a null body if Typ is an interface or a non-task |
| -- type. |
| |
| function Make_Disp_Get_Task_Id_Spec |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the specification of the primitive operation |
| -- of type Typ used for retrieving the _task_id field of a task interface |
| -- class-wide type. |
| |
| function Make_Disp_Timed_Select_Body |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the body of the primitive operation of type |
| -- Typ used for dispatching in timed selects. Generate a null body if Nul |
| -- is an interface type. |
| |
| function Make_Disp_Timed_Select_Spec |
| (Typ : Entity_Id) return Node_Id; |
| -- Ada 2005 (AI-345): Generate the specification of the primitive operation |
| -- of type Typ used for dispatching in timed selects. |
| |
| function Make_Select_Specific_Data_Table |
| (Typ : Entity_Id) return List_Id; |
| -- Ada 2005 (AI-345): Create and populate the auxiliary table in the TSD |
| -- of Typ used for dispatching in asynchronous, conditional and timed |
| -- selects. Generate code to set the primitive operation kinds and entry |
| -- indices of primitive operations and primitive wrappers. |
| |
| procedure Make_Secondary_DT |
| (Typ : Entity_Id; |
| Ancestor_Typ : Entity_Id; |
| Suffix_Index : Int; |
| Iface : Entity_Id; |
| AI_Tag : Entity_Id; |
| Acc_Disp_Tables : in out Elist_Id; |
| Result : out List_Id); |
| -- Ada 2005 (AI-251): Expand the declarations for the Secondary Dispatch |
| -- Table of Typ associated with Iface (each abstract interface implemented |
| -- by Typ has a secondary dispatch table). The arguments Typ, Ancestor_Typ |
| -- and Suffix_Index are used to generate an unique external name which |
| -- is added at the end of Acc_Disp_Tables; this external name will be |
| -- used later by the subprogram Exp_Ch3.Build_Init_Procedure. |
| |
| procedure Set_All_DT_Position (Typ : Entity_Id); |
| -- Set the DT_Position field for each primitive operation. In the CPP |
| -- Class case check that no pragma CPP_Virtual is missing and that the |
| -- DT_Position are coherent |
| |
| procedure Set_Default_Constructor (Typ : Entity_Id); |
| -- Typ is a CPP_Class type. Create the Init procedure of that type to |
| -- be the default constructor (i.e. the function returning this type, |
| -- having a pragma CPP_Constructor and no parameter) |
| |
| procedure Write_DT (Typ : Entity_Id); |
| pragma Export (Ada, Write_DT); |
| -- Debugging procedure (to be called within gdb) |
| |
| end Exp_Disp; |
