1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              E X P _ C H 6                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2020, 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 BIP_Suffix_Kind (E : Entity_Id) return BIP_Formal_Kind;
106   --  Ada 2005 (AI-318-02): Returns the kind of the given BIP extra formal.
107
108   function Build_In_Place_Formal
109     (Func : Entity_Id;
110      Kind : BIP_Formal_Kind) return Entity_Id;
111   --  Ada 2005 (AI-318-02): Locates and returns the entity for the implicit
112   --  build-in-place formal parameter of the given kind associated with the
113   --  function Func, and returns its Entity_Id. It is a bug if not found; the
114   --  caller should ensure this is called only when the extra formal exists.
115
116   function Build_Procedure_Body_Form
117     (Func_Id : Entity_Id; Func_Body : Node_Id) return Node_Id;
118   --  Create a procedure body which emulates the behavior of function Func_Id.
119   --  Func_Body is the root of the body of the function before its analysis.
120   --  The returned node is the root of the procedure body which will replace
121   --  the original function body, which is not needed for the C program.
122
123   function Is_Build_In_Place_Entity (E : Entity_Id) return Boolean;
124   --  Ada 2005 (AI-318-02): Returns True if E is a BIP entity.
125
126   function Is_Build_In_Place_Result_Type (Typ : Entity_Id) return Boolean;
127   --  Ada 2005 (AI-318-02): Returns True if functions returning the type use
128   --  build-in-place protocols. For inherently limited types, this must be
129   --  True in >= Ada 2005, and must be False in Ada 95. For other types, it
130   --  can be True or False, and the decision should be based on efficiency,
131   --  and should be the same for all language versions, so that mixed-dialect
132   --  programs will work.
133   --
134   --  For inherently limited types in Ada 2005, True means that calls will
135   --  actually be build-in-place in all cases. For other types, build-in-place
136   --  will be used when possible, but we need to make a copy at the call site
137   --  in some cases, notably assignment statements.
138
139   function Is_Build_In_Place_Function (E : Entity_Id) return Boolean;
140   --  Ada 2005 (AI-318-02): Returns True if E denotes a function, generic
141   --  function, or access-to-function type for which
142   --  Is_Build_In_Place_Result_Type is True. However, we never use
143   --  build-in-place if the convention is other than Ada, because that would
144   --  disturb mixed-language programs.
145
146   function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean;
147   --  Ada 2005 (AI-318-02): Returns True if N denotes a call to a function
148   --  that requires handling as a build-in-place call (possibly qualified or
149   --  converted).
150
151   function Is_Null_Procedure (Subp : Entity_Id) return Boolean;
152   --  Predicate to recognize stubbed procedures and null procedures, which
153   --  can be inlined unconditionally in all cases.
154
155   procedure Make_Build_In_Place_Call_In_Allocator
156     (Allocator     : Node_Id;
157      Function_Call : Node_Id);
158   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
159   --  occurs as the expression initializing an allocator, by passing access
160   --  to the allocated object as an additional parameter of the function call.
161   --  A new access object is declared that is initialized to the result of the
162   --  allocator, passed to the function, and the allocator is rewritten to
163   --  refer to that access object. Function_Call must denote either an
164   --  N_Function_Call node for which Is_Build_In_Place_Call is True, or else
165   --  an N_Qualified_Expression node applied to such a function call.
166
167   procedure Make_Build_In_Place_Call_In_Anonymous_Context
168     (Function_Call : Node_Id);
169   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
170   --  occurs in a context that does not provide a separate object. A temporary
171   --  object is created to act as the return object and an access to the
172   --  temporary is passed as an additional parameter of the call. This occurs
173   --  in contexts such as subprogram call actuals and object renamings.
174   --  Function_Call must denote either an N_Function_Call node for which
175   --  Is_Build_In_Place_Call is True, or else an N_Qualified_Expression node
176   --  applied to such a function call.
177
178   procedure Make_Build_In_Place_Call_In_Assignment
179     (Assign        : Node_Id;
180      Function_Call : Node_Id);
181   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
182   --  occurs as the right-hand side of an assignment statement by passing
183   --  access to the left-hand side as an additional parameter of the function
184   --  call. Assign must denote a N_Assignment_Statement. Function_Call must
185   --  denote either an N_Function_Call node for which Is_Build_In_Place_Call
186   --  is True, or an N_Qualified_Expression node applied to such a function
187   --  call.
188
189   procedure Make_Build_In_Place_Call_In_Object_Declaration
190     (Obj_Decl      : Node_Id;
191      Function_Call : Node_Id);
192   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
193   --  occurs as the expression initializing an object declaration by
194   --  passing access to the declared object as an additional parameter of the
195   --  function call. Function_Call must denote either an N_Function_Call node
196   --  for which Is_Build_In_Place_Call is True, or an N_Qualified_Expression
197   --  node applied to such a function call.
198
199   procedure Make_Build_In_Place_Iface_Call_In_Allocator
200     (Allocator     : Node_Id;
201      Function_Call : Node_Id);
202   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
203   --  occurs as the expression initializing an allocator, by passing access
204   --  to the allocated object as an additional parameter of the function call.
205   --  Function_Call must denote an expression containing a BIP function call
206   --  and an enclosing call to Ada.Tags.Displace to displace the pointer to
207   --  the returned BIP object to reference the secondary dispatch table of
208   --  an interface.
209
210   procedure Make_Build_In_Place_Iface_Call_In_Anonymous_Context
211     (Function_Call : Node_Id);
212   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
213   --  occurs in a context that does not provide a separate object. A temporary
214   --  object is created to act as the return object and an access to the
215   --  temporary is passed as an additional parameter of the call. This occurs
216   --  in contexts such as subprogram call actuals and object renamings.
217   --  Function_Call must denote an expression containing a BIP function call
218   --  and an enclosing call to Ada.Tags.Displace to displace the pointer to
219   --  the returned BIP object to reference the secondary dispatch table of
220   --  an interface.
221
222   procedure Make_Build_In_Place_Iface_Call_In_Object_Declaration
223     (Obj_Decl      : Node_Id;
224      Function_Call : Node_Id);
225   --  Ada 2005 (AI-318-02): Handle a call to a build-in-place function that
226   --  occurs as the expression initializing an object declaration by passing
227   --  access to the declared object as an additional parameter of the function
228   --  call. Function_Call must denote an expression containing a BIP function
229   --  call and an enclosing call to Ada.Tags.Displace to displace the pointer
230   --  to the returned BIP object to reference the secondary dispatch table of
231   --  an interface.
232
233   procedure Make_CPP_Constructor_Call_In_Allocator
234     (Allocator     : Node_Id;
235      Function_Call : Node_Id);
236   --  Handle a call to a CPP constructor that occurs as the expression that
237   --  initializes an allocator, by passing access to the allocated object as
238   --  an additional parameter of the constructor call. A new access object is
239   --  declared that is initialized to the result of the allocator, passed to
240   --  the constructor, and the allocator is rewritten to refer to that access
241   --  object. Function_Call must denote a call to a CPP_Constructor function.
242
243   function Might_Have_Tasks (Typ : Entity_Id) return Boolean;
244   --  Return True when type Typ has tasks or when it is a limited class-wide
245   --  type (or subtype), since it might have task components.
246
247   function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean;
248   --  Ada 2005 (AI-318-02): Return True if the function needs an implicit
249   --  BIP_Alloc_Form parameter (see type BIP_Formal_Kind).
250
251   function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean;
252   --  Ada 2005 (AI-318-02): Return True if the result subtype of function
253   --  Func_Id might need finalization actions. This includes build-in-place
254   --  functions with tagged result types, since they can be invoked via
255   --  dispatching calls, and descendant types may require finalization.
256
257   function Needs_BIP_Task_Actuals (Func_Id : Entity_Id) return Boolean;
258   --  Return True if the function returns an object of a type that has tasks.
259
260   function Unqual_BIP_Iface_Function_Call (Expr : Node_Id) return Node_Id;
261   --  Return the inner BIP function call removing any qualification from Expr
262   --  including qualified expressions, type conversions, references, unchecked
263   --  conversions and calls to displace the pointer to the object, if Expr is
264   --  an expression containing a call displacing the pointer to the BIP object
265   --  to reference the secondary dispatch table of an interface; otherwise
266   --  return Empty.
267
268end Exp_Ch6;
269