1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              E X P _ C H 6                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2012, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
19-- http://www.gnu.org/licenses for a complete copy of the license.          --
20--                                                                          --
21-- GNAT was originally developed  by the GNAT team at  New York University. --
22-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23--                                                                          --
24------------------------------------------------------------------------------
25
26--  Expand routines for chapter 6 constructs
27
28with Types; use Types;
29
30package Exp_Ch6 is
31
32   procedure Expand_N_Extended_Return_Statement (N : Node_Id);
33   procedure Expand_N_Function_Call             (N : Node_Id);
34   procedure Expand_N_Procedure_Call_Statement  (N : Node_Id);
35   procedure Expand_N_Simple_Return_Statement   (N : Node_Id);
36   procedure Expand_N_Subprogram_Body           (N : Node_Id);
37   procedure Expand_N_Subprogram_Body_Stub      (N : Node_Id);
38   procedure Expand_N_Subprogram_Declaration    (N : Node_Id);
39
40   procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id);
41   --  For each actual of an in-out or out parameter which is a numeric
42   --  (view) conversion of the form T (A), where A denotes a variable,
43   --  we insert the declaration:
44   --
45   --    Temp : T[ := T (A)];
46   --
47   --  prior to the call. Then we replace the actual with a reference to Temp,
48   --  and append the assignment:
49   --
50   --    A := TypeA (Temp);
51   --
52   --  after the call. Here TypeA is the actual type of variable A. For out
53   --  parameters, the initial declaration has no expression. If A is not an
54   --  entity name, we generate instead:
55   --
56   --    Var  : TypeA renames A;
57   --    Temp : T := Var;       --  omitting expression for out parameter.
58   --    ...
59   --    Var := TypeA (Temp);
60   --
61   --  For other in-out parameters, we emit the required constraint checks
62   --  before and/or after the call.
63   --
64   --  For all parameter modes, actuals that denote components and slices of
65   --  packed arrays are expanded into suitable temporaries.
66   --
67   --  For non-scalar objects that are possibly unaligned, add call by copy
68   --  code (copy in for IN and IN OUT, copy out for OUT and IN OUT).
69
70   procedure Expand_Call (N : Node_Id);
71   --  This procedure contains common processing for Expand_N_Function_Call,
72   --  Expand_N_Procedure_Statement, and Expand_N_Entry_Call.
73
74   procedure Freeze_Subprogram (N : Node_Id);
75   --  generate the appropriate expansions related to Subprogram freeze
76   --  nodes (e.g. the filling of the corresponding Dispatch Table for
77   --  Primitive Operations)
78
79   --  The following type defines the various forms of allocation used for the
80   --  results of build-in-place function calls.
81
82   type BIP_Allocation_Form is
83     (Unspecified,
84      Caller_Allocation,
85      Secondary_Stack,
86      Global_Heap,
87      User_Storage_Pool);
88
89   type BIP_Formal_Kind is
90   --  Ada 2005 (AI-318-02): This type defines the kinds of implicit extra
91   --  formals created for build-in-place functions. The order of these
92   --  enumeration literals matches the order in which the formals are
93   --  declared. See Sem_Ch6.Create_Extra_Formals.
94
95     (BIP_Alloc_Form,
96      --  Present if result subtype is unconstrained or tagged. Indicates
97      --  whether the return object is allocated by the caller or callee, and
98      --  if the callee, whether to use the secondary stack or the heap. See
99      --  Create_Extra_Formals.
100
101      BIP_Storage_Pool,
102      --  Present if result subtype is unconstrained or tagged. If
103      --  BIP_Alloc_Form = User_Storage_Pool, this is a pointer to the pool
104      --  (of type access to Root_Storage_Pool'Class). Otherwise null.
105
106      BIP_Finalization_Master,
107      --  Present if result type needs finalization. Pointer to caller's
108      --  finalization master.
109
110      BIP_Task_Master,
111      --  Present if result type contains tasks. Master associated with
112      --  calling context.
113
114      BIP_Activation_Chain,
115      --  Present if result type contains tasks. Caller's activation chain
116
117      BIP_Object_Access);
118      --  Present for all build-in-place functions. Address at which to place
119      --  the return object, or null if BIP_Alloc_Form indicates allocated by
120      --  callee.
121      --
122      --  ??? We might also need to be able to pass in a constrained flag.
123
124   function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String;
125   --  Ada 2005 (AI-318-02): Returns a string to be used as the suffix of names
126   --  for build-in-place formal parameters of the given kind.
127
128   function Build_In_Place_Formal
129     (Func : Entity_Id;
130      Kind : BIP_Formal_Kind) return Entity_Id;
131   --  Ada 2005 (AI-318-02): Locates and returns the entity for the implicit
132   --  build-in-place formal parameter of the given kind associated with the
133   --  function Func, and returns its Entity_Id. It is a bug if not found; the
134   --  caller should ensure this is called only when the extra formal exists.
135
136   function Is_Build_In_Place_Function (E : Entity_Id) return Boolean;
137   --  Ada 2005 (AI-318-02): Returns True if E denotes a function, generic
138   --  function, or access-to-function type whose result must be built in
139   --  place; otherwise returns False. For Ada 2005, this is currently
140   --  restricted to the set of functions whose result subtype is an inherently
141   --  limited type. In Ada 95, this must be False for inherently limited
142   --  result types (but currently returns False for all Ada 95 functions).
143   --  Eventually we plan to support build-in-place for nonlimited types.
144   --  Build-in-place is usually more efficient for large things, and less
145   --  efficient for small things. However, we never use build-in-place if the
146   --  convention is other than Ada, because that would disturb mixed-language
147   --  programs. Note that for the non-inherently-limited cases, we must make
148   --  the same decision for Ada 95 and 2005, so that mixed-dialect programs
149   --  will work.
150
151   function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean;
152   --  Ada 2005 (AI-318-02): Returns True if N denotes a call to a function
153   --  that requires handling as a build-in-place call or is a qualified
154   --  expression applied to such a call; otherwise returns False.
155
156   function Is_Null_Procedure (Subp : Entity_Id) return Boolean;
157   --  Predicate to recognize stubbed procedures and null procedures, which
158   --  can be inlined unconditionally in all cases.
159
160   procedure List_Inlining_Info;
161   --  Generate listing of calls inlined by the frontend plus listing of
162   --  calls to inline subprograms passed to the backend.
163
164   procedure Make_Build_In_Place_Call_In_Allocator
165     (Allocator     : Node_Id;
166      Function_Call : Node_Id);
167   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
168   --  occurs as the expression initializing an allocator, by passing access
169   --  to the allocated object as an additional parameter of the function call.
170   --  A new access object is declared that is initialized to the result of the
171   --  allocator, passed to the function, and the allocator is rewritten to
172   --  refer to that access object. Function_Call must denote either an
173   --  N_Function_Call node for which Is_Build_In_Place_Call is True, or else
174   --  an N_Qualified_Expression node applied to such a function call.
175
176   procedure Make_Build_In_Place_Call_In_Anonymous_Context
177     (Function_Call : Node_Id);
178   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
179   --  occurs in a context that does not provide a separate object. A temporary
180   --  object is created to act as the return object and an access to the
181   --  temporary is passed as an additional parameter of the call. This occurs
182   --  in contexts such as subprogram call actuals and object renamings.
183   --  Function_Call must denote either an N_Function_Call node for which
184   --  Is_Build_In_Place_Call is True, or else an N_Qualified_Expression node
185   --  applied to such a function call.
186
187   procedure Make_Build_In_Place_Call_In_Assignment
188     (Assign        : Node_Id;
189      Function_Call : Node_Id);
190   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
191   --  occurs as the right-hand side of an assignment statement by passing
192   --  access to the left-hand side as an additional parameter of the function
193   --  call. Assign must denote a N_Assignment_Statement. Function_Call must
194   --  denote either an N_Function_Call node for which Is_Build_In_Place_Call
195   --  is True, or an N_Qualified_Expression node applied to such a function
196   --  call.
197
198   procedure Make_Build_In_Place_Call_In_Object_Declaration
199     (Object_Decl   : Node_Id;
200      Function_Call : Node_Id);
201   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
202   --  occurs as the expression initializing an object declaration by
203   --  passing access to the declared object as an additional parameter of the
204   --  function call. Function_Call must denote either an N_Function_Call node
205   --  for which Is_Build_In_Place_Call is True, or an N_Qualified_Expression
206   --  node applied to such a function call.
207
208   procedure Make_CPP_Constructor_Call_In_Allocator
209     (Allocator     : Node_Id;
210      Function_Call : Node_Id);
211   --  Handle a call to a CPP constructor that occurs as the expression that
212   --  initializes an allocator, by passing access to the allocated object as
213   --  an additional parameter of the constructor call. A new access object is
214   --  declared that is initialized to the result of the allocator, passed to
215   --  the constructor, and the allocator is rewritten to refer to that access
216   --  object. Function_Call must denote a call to a CPP_Constructor function.
217
218   function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean;
219   --  Ada 2005 (AI-318-02): Return True if the function needs an implicit
220   --  BIP_Alloc_Form parameter (see type BIP_Formal_Kind).
221
222   function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean;
223   --  Ada 2005 (AI-318-02): Return True if the result subtype of function
224   --  Func_Id needs finalization actions.
225
226   function Needs_Result_Accessibility_Level
227     (Func_Id : Entity_Id) return Boolean;
228   --  Ada 2012 (AI05-0234): Return True if the function needs an implicit
229   --  parameter to identify the accessibility level of the function result
230   --  "determined by the point of call".
231
232   procedure Add_Extra_Actual_To_Call
233     (Subprogram_Call : Node_Id;
234      Extra_Formal    : Entity_Id;
235      Extra_Actual    : Node_Id);
236   --  Adds Extra_Actual as a named parameter association for the formal
237   --  Extra_Formal in Subprogram_Call.
238
239end Exp_Ch6;
240