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Diffstat (limited to 'gcc/ada/exp_disp.ads')
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diff --git a/gcc/ada/exp_disp.ads b/gcc/ada/exp_disp.ads new file mode 100644 index 000000000..d2dd7760d --- /dev/null +++ b/gcc/ada/exp_disp.ads @@ -0,0 +1,391 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ D I S P -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1992-2010, 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 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 COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- 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_Requeue (15) - used in the expansion of dispatching requeue + -- statements. Null implementation is provided for protected, task + -- and synchronized interfaces. Protected and task types implementing + -- concurrent interfaces receive full bodies. See Expand_N_Requeue_ + -- Statement in Exp_Ch9 for more information. + + -- _Disp_Timed_Select (16) - 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. + + -- Life cycle 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 by Exp_Ch3.Predefined_Primitive_Freeze + + -- Thunks for PPOs are created by Make_DT + + -- Dispatch table positions of PPOs are set by Set_All_DT_Position + + -- Calls to PPOs proceed as regular dispatching calls. If the PPO + -- has a thunk, a call proceeds as a regular dispatching call with + -- a thunk. + + -- Guidelines for addition of new predefined primitive operations + + -- Update the value of constant Max_Predef_Prims in a-tags.ads to + -- indicate 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_Disp. + + -- 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.Max_Predef_Prims - indirect use + -- Exp_Disp.Default_Prim_Op_Position - indirect use + -- Exp_Disp.Set_All_DT_Position - direct use + + procedure Apply_Tag_Checks (Call_Node : Node_Id); + -- Generate checks required on dispatching calls + + function Building_Static_DT (Typ : Entity_Id) return Boolean; + pragma Inline (Building_Static_DT); + -- Returns true when building statically allocated dispatch tables + + procedure Build_Static_Dispatch_Tables (N : Node_Id); + -- N is a library level package declaration or package body. Build the + -- static dispatch table of the tagged types defined at library level. In + -- case of package declarations with private part the generated nodes are + -- added at the end of the list of private declarations. Otherwise they are + -- added to the end of the list of public declarations. In case of package + -- bodies they are added to the end of the list of declarations of the + -- package body. + + function Convert_Tag_To_Interface + (Typ : Entity_Id; Expr : Node_Id) return Node_Id; + pragma Inline (Convert_Tag_To_Interface); + -- This function is used in class-wide interface conversions; the expanded + -- code generated to convert a tagged object to a class-wide interface type + -- involves referencing the tag component containing the secondary dispatch + -- table associated with the interface. Given the expression Expr that + -- references a tag component, we cannot generate an unchecked conversion + -- to leave the expression decorated with the class-wide interface type Typ + -- because an unchecked conversion cannot be seen as a no-op. An unchecked + -- conversion is conceptually a function call and therefore the RM allows + -- the backend to obtain a copy of the value of the actual object and store + -- it in some other place (like a register); in such case the interface + -- conversion is not equivalent to a displacement of the pointer to the + -- interface and any further displacement fails. Although the functionality + -- of this function is simple and could be done directly, the purpose of + -- this routine is to leave well documented in the sources these + -- occurrences. + + -- If Expr is an N_Selected_Component that references a tag generate: + -- type ityp is non null access Typ; + -- ityp!(Expr'Address).all + + -- if Expr is an N_Function_Call to Ada.Tags.Displace then generate: + -- type ityp is non null access Typ; + -- ityp!(Expr).all + + function CPP_Num_Prims (Typ : Entity_Id) return Nat; + -- Return the number of primitives of the C++ part of the dispatch table. + -- For types that are not derivations of CPP types return 0. + + 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 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. + + procedure Expand_Interface_Thunk + (Prim : Node_Id; + Thunk_Id : out Entity_Id; + Thunk_Code : out Node_Id); + -- Ada 2005 (AI-251): When a tagged type implements abstract interfaces we + -- generate additional subprograms (thunks) associated with each primitive + -- Prim to have a layout compatible with the C++ ABI. The thunk displaces + -- the pointers to the actuals that depend on the controlling type before + -- transferring control to the target subprogram. If there is no need to + -- generate the thunk then Thunk_Id and Thunk_Code are set to Empty. + -- Otherwise they are set to the defining identifier and the subprogram + -- body of the generated thunk. + + function Has_CPP_Constructors (Typ : Entity_Id) return Boolean; + -- Returns true if the type has CPP constructors + + function Is_Predefined_Dispatching_Operation (E : Entity_Id) return Boolean; + -- Ada 2005 (AI-251): Determines if E is a predefined primitive operation + + function Is_Predefined_Internal_Operation (E : Entity_Id) return Boolean; + -- Similar to the previous one, but excludes stream operations, because + -- these may be overridden, and need extra formals, like user-defined + -- operations. + + function Is_Predefined_Interface_Primitive (E : Entity_Id) return Boolean; + -- Ada 2005 (AI-345): Returns True if E is one of the predefined primitives + -- required to implement interfaces. + + function Make_DT (Typ : Entity_Id; N : Node_Id := Empty) return List_Id; + -- Expand the declarations for the Dispatch Table. The node N is the + -- declaration that forces the generation of the table. It is used to place + -- error messages when the declaration leads to the freezing of a given + -- primitive operation that has an incomplete non- tagged formal. + + 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 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_Requeue_Body + (Typ : Entity_Id) return Node_Id; + -- Ada 2005 (AI05-0030): Generate the body of the primitive operation of + -- type Typ used for dispatching on requeue statements. Generate a body + -- containing a single null-statement if Typ is an interface type. + + function Make_Disp_Requeue_Spec + (Typ : Entity_Id) return Node_Id; + -- Ada 2005 (AI05-0030): Generate the specification of the primitive + -- operation of type Typ used for dispatching requeue statements. + + 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 body containing + -- a single null-statement if Typ 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 + -- indexes of primitive operations and primitive wrappers. + + function Make_Tags (Typ : Entity_Id) return List_Id; + -- Generate the entities associated with the primary and secondary tags of + -- Typ and fill the contents of Access_Disp_Table. In case of library level + -- tagged types this routine imports the forward declaration of the tag + -- entity, that will be declared and exported by Make_DT. + + function Register_Primitive + (Loc : Source_Ptr; + Prim : Entity_Id) return List_Id; + -- Build code to register Prim in the primary or secondary dispatch table. + -- If Prim is associated with a secondary dispatch table then generate also + -- its thunk and register it in the associated secondary dispatch table. + -- In general the dispatch tables are always generated by Make_DT and + -- Make_Secondary_DT; this routine is only used in two corner cases: + -- + -- 1) To construct the dispatch table of a tagged type whose parent + -- is a CPP_Class (see Build_Init_Procedure). + -- 2) To handle late overriding of dispatching operations (see + -- Check_Dispatching_Operation and Make_DT). + -- + -- The caller is responsible for inserting the generated code in the + -- proper place. + + 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_CPP_Constructors (Typ : Entity_Id); + -- Typ is a CPP_Class type. Create the Init procedures of that type + -- required to handle its default and non-default constructors. The + -- functions to which pragma CPP_Constructor is applied in the sources + -- are functions returning this type, and having an implicit access to the + -- target object in its first argument; such implicit argument is explicit + -- in the IP procedures built here. + + procedure Set_DTC_Entity_Value + (Tagged_Type : Entity_Id; + Prim : Entity_Id); + -- Set the definite value of the DTC_Entity value associated with a given + -- primitive of a tagged type. + + procedure Write_DT (Typ : Entity_Id); + pragma Export (Ada, Write_DT); + -- Debugging procedure (to be called within gdb) + +end Exp_Disp; |