1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              E X P _ C H 6                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2019, 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_Call (N : Node_Id);
41   --  This procedure contains common processing for Expand_N_Function_Call,
42   --  Expand_N_Procedure_Statement, and Expand_N_Entry_Call.
43
44   procedure Freeze_Subprogram (N : Node_Id);
45   --  generate the appropriate expansions related to Subprogram freeze
46   --  nodes (e.g. the filling of the corresponding Dispatch Table for
47   --  Primitive Operations)
48
49   --  The following type defines the various forms of allocation used for the
50   --  results of build-in-place function calls.
51
52   type BIP_Allocation_Form is
53     (Unspecified,
54      Caller_Allocation,
55      Secondary_Stack,
56      Global_Heap,
57      User_Storage_Pool);
58
59   type BIP_Formal_Kind is
60   --  Ada 2005 (AI-318-02): This type defines the kinds of implicit extra
61   --  formals created for build-in-place functions. The order of these
62   --  enumeration literals matches the order in which the formals are
63   --  declared. See Sem_Ch6.Create_Extra_Formals.
64
65     (BIP_Alloc_Form,
66      --  Present if result subtype is unconstrained or tagged. Indicates
67      --  whether the return object is allocated by the caller or callee, and
68      --  if the callee, whether to use the secondary stack or the heap. See
69      --  Create_Extra_Formals.
70
71      BIP_Storage_Pool,
72      --  Present if result subtype is unconstrained or tagged. If
73      --  BIP_Alloc_Form = User_Storage_Pool, this is a pointer to the pool
74      --  (of type access to Root_Storage_Pool'Class). Otherwise null.
75
76      BIP_Finalization_Master,
77      --  Present if result type needs finalization. Pointer to caller's
78      --  finalization master.
79
80      BIP_Task_Master,
81      --  Present if result type contains tasks. Master associated with
82      --  calling context.
83
84      BIP_Activation_Chain,
85      --  Present if result type contains tasks. Caller's activation chain
86
87      BIP_Object_Access);
88      --  Present for all build-in-place functions. Address at which to place
89      --  the return object, or null if BIP_Alloc_Form indicates allocated by
90      --  callee.
91      --
92      --  ??? We might also need to be able to pass in a constrained flag.
93
94   procedure Add_Extra_Actual_To_Call
95     (Subprogram_Call : Node_Id;
96      Extra_Formal    : Entity_Id;
97      Extra_Actual    : Node_Id);
98   --  Adds Extra_Actual as a named parameter association for the formal
99   --  Extra_Formal in Subprogram_Call.
100
101   function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String;
102   --  Ada 2005 (AI-318-02): Returns a string to be used as the suffix of names
103   --  for build-in-place formal parameters of the given kind.
104
105   function Build_In_Place_Formal
106     (Func : Entity_Id;
107      Kind : BIP_Formal_Kind) return Entity_Id;
108   --  Ada 2005 (AI-318-02): Locates and returns the entity for the implicit
109   --  build-in-place formal parameter of the given kind associated with the
110   --  function Func, and returns its Entity_Id. It is a bug if not found; the
111   --  caller should ensure this is called only when the extra formal exists.
112
113   function Build_Procedure_Body_Form
114     (Func_Id : Entity_Id; Func_Body : Node_Id) return Node_Id;
115   --  Create a procedure body which emulates the behavior of function Func_Id.
116   --  Func_Body is the root of the body of the function before its analysis.
117   --  The returned node is the root of the procedure body which will replace
118   --  the original function body, which is not needed for the C program.
119
120   function Is_Build_In_Place_Result_Type (Typ : Entity_Id) return Boolean;
121   --  Ada 2005 (AI-318-02): Returns True if functions returning the type use
122   --  build-in-place protocols. For inherently limited types, this must be
123   --  True in >= Ada 2005, and must be False in Ada 95. For other types, it
124   --  can be True or False, and the decision should be based on efficiency,
125   --  and should be the same for all language versions, so that mixed-dialect
126   --  programs will work.
127   --
128   --  For inherently limited types in Ada 2005, True means that calls will
129   --  actually be build-in-place in all cases. For other types, build-in-place
130   --  will be used when possible, but we need to make a copy at the call site
131   --  in some cases, notably assignment statements.
132
133   function Is_Build_In_Place_Function (E : Entity_Id) return Boolean;
134   --  Ada 2005 (AI-318-02): Returns True if E denotes a function, generic
135   --  function, or access-to-function type for which
136   --  Is_Build_In_Place_Result_Type is True. However, we never use
137   --  build-in-place if the convention is other than Ada, because that would
138   --  disturb mixed-language programs.
139
140   function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean;
141   --  Ada 2005 (AI-318-02): Returns True if N denotes a call to a function
142   --  that requires handling as a build-in-place call (possibly qualified or
143   --  converted).
144
145   function Is_Null_Procedure (Subp : Entity_Id) return Boolean;
146   --  Predicate to recognize stubbed procedures and null procedures, which
147   --  can be inlined unconditionally in all cases.
148
149   procedure Make_Build_In_Place_Call_In_Allocator
150     (Allocator     : Node_Id;
151      Function_Call : Node_Id);
152   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
153   --  occurs as the expression initializing an allocator, by passing access
154   --  to the allocated object as an additional parameter of the function call.
155   --  A new access object is declared that is initialized to the result of the
156   --  allocator, passed to the function, and the allocator is rewritten to
157   --  refer to that access object. Function_Call must denote either an
158   --  N_Function_Call node for which Is_Build_In_Place_Call is True, or else
159   --  an N_Qualified_Expression node applied to such a function call.
160
161   procedure Make_Build_In_Place_Call_In_Anonymous_Context
162     (Function_Call : Node_Id);
163   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
164   --  occurs in a context that does not provide a separate object. A temporary
165   --  object is created to act as the return object and an access to the
166   --  temporary is passed as an additional parameter of the call. This occurs
167   --  in contexts such as subprogram call actuals and object renamings.
168   --  Function_Call must denote either an N_Function_Call node for which
169   --  Is_Build_In_Place_Call is True, or else an N_Qualified_Expression node
170   --  applied to such a function call.
171
172   procedure Make_Build_In_Place_Call_In_Assignment
173     (Assign        : Node_Id;
174      Function_Call : Node_Id);
175   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
176   --  occurs as the right-hand side of an assignment statement by passing
177   --  access to the left-hand side as an additional parameter of the function
178   --  call. Assign must denote a N_Assignment_Statement. Function_Call must
179   --  denote either an N_Function_Call node for which Is_Build_In_Place_Call
180   --  is True, or an N_Qualified_Expression node applied to such a function
181   --  call.
182
183   procedure Make_Build_In_Place_Call_In_Object_Declaration
184     (Obj_Decl      : Node_Id;
185      Function_Call : Node_Id);
186   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
187   --  occurs as the expression initializing an object declaration by
188   --  passing access to the declared object as an additional parameter of the
189   --  function call. Function_Call must denote either an N_Function_Call node
190   --  for which Is_Build_In_Place_Call is True, or an N_Qualified_Expression
191   --  node applied to such a function call.
192
193   procedure Make_Build_In_Place_Iface_Call_In_Allocator
194     (Allocator     : Node_Id;
195      Function_Call : Node_Id);
196   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
197   --  occurs as the expression initializing an allocator, by passing access
198   --  to the allocated object as an additional parameter of the function call.
199   --  Function_Call must denote an expression containing a BIP function call
200   --  and an enclosing call to Ada.Tags.Displace to displace the pointer to
201   --  the returned BIP object to reference the secondary dispatch table of
202   --  an interface.
203
204   procedure Make_Build_In_Place_Iface_Call_In_Anonymous_Context
205     (Function_Call : Node_Id);
206   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
207   --  occurs in a context that does not provide a separate object. A temporary
208   --  object is created to act as the return object and an access to the
209   --  temporary is passed as an additional parameter of the call. This occurs
210   --  in contexts such as subprogram call actuals and object renamings.
211   --  Function_Call must denote an expression containing a BIP function call
212   --  and an enclosing call to Ada.Tags.Displace to displace the pointer to
213   --  the returned BIP object to reference the secondary dispatch table of
214   --  an interface.
215
216   procedure Make_Build_In_Place_Iface_Call_In_Object_Declaration
217     (Obj_Decl      : Node_Id;
218      Function_Call : Node_Id);
219   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
220   --  occurs as the expression initializing an object declaration by passing
221   --  access to the declared object as an additional parameter of the function
222   --  call. Function_Call must denote an expression containing a BIP function
223   --  call and an enclosing call to Ada.Tags.Displace to displace the pointer
224   --  to the returned BIP object to reference the secondary dispatch table of
225   --  an interface.
226
227   procedure Make_CPP_Constructor_Call_In_Allocator
228     (Allocator     : Node_Id;
229      Function_Call : Node_Id);
230   --  Handle a call to a CPP constructor that occurs as the expression that
231   --  initializes an allocator, by passing access to the allocated object as
232   --  an additional parameter of the constructor call. A new access object is
233   --  declared that is initialized to the result of the allocator, passed to
234   --  the constructor, and the allocator is rewritten to refer to that access
235   --  object. Function_Call must denote a call to a CPP_Constructor function.
236
237   function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean;
238   --  Ada 2005 (AI-318-02): Return True if the function needs an implicit
239   --  BIP_Alloc_Form parameter (see type BIP_Formal_Kind).
240
241   function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean;
242   --  Ada 2005 (AI-318-02): Return True if the result subtype of function
243   --  Func_Id might need finalization actions. This includes build-in-place
244   --  functions with tagged result types, since they can be invoked via
245   --  dispatching calls, and descendant types may require finalization.
246
247   function Needs_Result_Accessibility_Level
248     (Func_Id : Entity_Id) return Boolean;
249   --  Ada 2012 (AI05-0234): Return True if the function needs an implicit
250   --  parameter to identify the accessibility level of the function result
251   --  "determined by the point of call".
252
253   function Unqual_BIP_Iface_Function_Call (Expr : Node_Id) return Node_Id;
254   --  Return the inner BIP function call removing any qualification from Expr
255   --  including qualified expressions, type conversions, references, unchecked
256   --  conversions and calls to displace the pointer to the object, if Expr is
257   --  an expression containing a call displacing the pointer to the BIP object
258   --  to reference the secondary dispatch table of an interface; otherwise
259   --  return Empty.
260
261end Exp_Ch6;
262