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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                              E X P _ C H 6                               --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2011, 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.      --

--                                                                          --

------------------------------------------------------------------------------

--  Expand routines for chapter 6 constructs

with Types; use Types;

package Exp_Ch6 is

   procedure Expand_N_Extended_Return_Statement (N : Node_Id);

   procedure Expand_N_Function_Call             (N : Node_Id);

   procedure Expand_N_Procedure_Call_Statement  (N : Node_Id);

   procedure Expand_N_Simple_Return_Statement   (N : Node_Id);

   procedure Expand_N_Subprogram_Body           (N : Node_Id);

   procedure Expand_N_Subprogram_Body_Stub      (N : Node_Id);

   procedure Expand_N_Subprogram_Declaration    (N : Node_Id);

   procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id);

   --  For each actual of an in-out or out parameter which is a numeric

   --  (view) conversion of the form T (A), where A denotes a variable,

   --  we insert the declaration:

   --

   --    Temp : T[ := T (A)];

   --

   --  prior to the call. Then we replace the actual with a reference to Temp,

   --  and append the assignment:

   --

   --    A := TypeA (Temp);

   --

   --  after the call. Here TypeA is the actual type of variable A. For out

   --  parameters, the initial declaration has no expression. If A is not an

   --  entity name, we generate instead:

   --

   --    Var  : TypeA renames A;

   --    Temp : T := Var;       --  omitting expression for out parameter.

   --    ...

   --    Var := TypeA (Temp);

   --

   --  For other in-out parameters, we emit the required constraint checks

   --  before and/or after the call.

   --

   --  For all parameter modes, actuals that denote components and slices of

   --  packed arrays are expanded into suitable temporaries.

   --

   --  For non-scalar objects that are possibly unaligned, add call by copy

   --  code (copy in for IN and IN OUT, copy out for OUT and IN OUT).

   procedure Expand_Call (N : Node_Id);

   --  This procedure contains common processing for Expand_N_Function_Call,

   --  Expand_N_Procedure_Statement, and Expand_N_Entry_Call.

   procedure Freeze_Subprogram (N : Node_Id);

   --  generate the appropriate expansions related to Subprogram freeze

   --  nodes (e.g. the filling of the corresponding Dispatch Table for

   --  Primitive Operations)

   --  The following type defines the various forms of allocation used for the

   --  results of build-in-place function calls.

   type BIP_Allocation_Form is

     (Unspecified,

      Caller_Allocation,

      Secondary_Stack,

      Global_Heap,

      User_Storage_Pool);

   type BIP_Formal_Kind is

   --  Ada 2005 (AI-318-02): This type defines the kinds of implicit extra

   --  formals created for build-in-place functions. The order of these

   --  enumeration literals matches the order in which the formals are

   --  declared. See Sem_Ch6.Create_Extra_Formals.

     (BIP_Alloc_Form,

      --  Present if result subtype is unconstrained or tagged. Indicates

      --  whether the return object is allocated by the caller or callee, and

      --  if the callee, whether to use the secondary stack or the heap. See

      --  Create_Extra_Formals.

      BIP_Storage_Pool,

      --  Present if result subtype is unconstrained or tagged. If

      --  BIP_Alloc_Form = User_Storage_Pool, this is a pointer to the pool

      --  (of type access to Root_Storage_Pool'Class). Otherwise null.

      BIP_Finalization_Master,

      --  Present if result type needs finalization. Pointer to caller's

      --  finalization master.

      BIP_Task_Master,

      --  Present if result type contains tasks. Master associated with

      --  calling context.

      BIP_Activation_Chain,

      --  Present if result type contains tasks. Caller's activation chain

      BIP_Object_Access);

      --  Present for all build-in-place functions. Address at which to place

      --  the return object, or null if BIP_Alloc_Form indicates allocated by

      --  callee.

      --

      --  ??? We might also need to be able to pass in a constrained flag.

   function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String;

   --  Ada 2005 (AI-318-02): Returns a string to be used as the suffix of names

   --  for build-in-place formal parameters of the given kind.

   function Build_In_Place_Formal

     (Func : Entity_Id;

      Kind : BIP_Formal_Kind) return Entity_Id;

   --  Ada 2005 (AI-318-02): Locates and returns the entity for the implicit

   --  build-in-place formal parameter of the given kind associated with the

   --  function Func, and returns its Entity_Id. It is a bug if not found; the

   --  caller should ensure this is called only when the extra formal exists.

   function Is_Build_In_Place_Function (E : Entity_Id) return Boolean;

   --  Ada 2005 (AI-318-02): Returns True if E denotes a function, generic

   --  function, or access-to-function type whose result must be built in

   --  place; otherwise returns False. For Ada 2005, this is currently

   --  restricted to the set of functions whose result subtype is an inherently

   --  limited type. In Ada 95, this must be False for inherently limited

   --  result types (but currently returns False for all Ada 95 functions).

   --  Eventually we plan to support build-in-place for nonlimited types.

   --  Build-in-place is usually more efficient for large things, and less

   --  efficient for small things. However, we never use build-in-place if the

   --  convention is other than Ada, because that would disturb mixed-language

   --  programs. Note that for the non-inherently-limited cases, we must make

   --  the same decision for Ada 95 and 2005, so that mixed-dialect programs

   --  will work.

   function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean;

   --  Ada 2005 (AI-318-02): Returns True if N denotes a call to a function

   --  that requires handling as a build-in-place call or is a qualified

   --  expression applied to such a call; otherwise returns False.

   function Is_Null_Procedure (Subp : Entity_Id) return Boolean;

   --  Predicate to recognize stubbed procedures and null procedures, which

   --  can be inlined unconditionally in all cases.

   procedure Make_Build_In_Place_Call_In_Allocator

     (Allocator     : Node_Id;

      Function_Call : Node_Id);

   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that

   --  occurs as the expression initializing an allocator, by passing access

   --  to the allocated object as an additional parameter of the function call.

   --  A new access object is declared that is initialized to the result of the

   --  allocator, passed to the function, and the allocator is rewritten to

   --  refer to that access object. Function_Call must denote either an

   --  N_Function_Call node for which Is_Build_In_Place_Call is True, or else

   --  an N_Qualified_Expression node applied to such a function call.

   procedure Make_Build_In_Place_Call_In_Anonymous_Context

     (Function_Call : Node_Id);

   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that

   --  occurs in a context that does not provide a separate object. A temporary

   --  object is created to act as the return object and an access to the

   --  temporary is passed as an additional parameter of the call. This occurs

   --  in contexts such as subprogram call actuals and object renamings.

   --  Function_Call must denote either an N_Function_Call node for which

   --  Is_Build_In_Place_Call is True, or else an N_Qualified_Expression node

   --  applied to such a function call.

   procedure Make_Build_In_Place_Call_In_Assignment

     (Assign        : Node_Id;

      Function_Call : Node_Id);

   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that

   --  occurs as the right-hand side of an assignment statement by passing

   --  access to the left-hand side as an additional parameter of the function

   --  call. Assign must denote a N_Assignment_Statement. Function_Call must

   --  denote either an N_Function_Call node for which Is_Build_In_Place_Call

   --  is True, or an N_Qualified_Expression node applied to such a function

   --  call.

   procedure Make_Build_In_Place_Call_In_Object_Declaration

     (Object_Decl   : Node_Id;

      Function_Call : Node_Id);

   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that

   --  occurs as the expression initializing an object declaration by

   --  passing access to the declared object as an additional parameter of the

   --  function call. Function_Call must denote either an N_Function_Call node

   --  for which Is_Build_In_Place_Call is True, or an N_Qualified_Expression

   --  node applied to such a function call.

   function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean;

   --  Ada 2005 (AI-318-02): Return True if the function needs an implicit

   --  BIP_Alloc_Form parameter (see type BIP_Formal_Kind).

   function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean;

   --  Ada 2005 (AI-318-02): Return True if the result subtype of function

   --  Func_Id needs finalization actions.

   function Needs_Result_Accessibility_Level

     (Func_Id : Entity_Id) return Boolean;

   --  Ada 2012 (AI05-0234): Return True if the function needs an implicit

   --  parameter to identify the accessibility level of the function result

   --  "determined by the point of call".

   procedure Add_Extra_Actual_To_Call

     (Subprogram_Call : Node_Id;

      Extra_Formal    : Entity_Id;

      Extra_Actual    : Node_Id);

   --  Adds Extra_Actual as a named parameter association for the formal

   --  Extra_Formal in Subprogram_Call.

end Exp_Ch6;