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[official-gcc.git] / gcc / ada / exp_smem.adb
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- E X P _ S M E M --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1998-2018, 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 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Einfo; use Einfo;
28 with Elists; use Elists;
29 with Exp_Ch7; use Exp_Ch7;
30 with Exp_Ch9; use Exp_Ch9;
31 with Exp_Tss; use Exp_Tss;
32 with Exp_Util; use Exp_Util;
33 with Nmake; use Nmake;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Rtsfind; use Rtsfind;
37 with Sem; use Sem;
38 with Sem_Aux; use Sem_Aux;
39 with Sem_Util; use Sem_Util;
40 with Sinfo; use Sinfo;
41 with Snames; use Snames;
42 with Stand; use Stand;
43 with Stringt; use Stringt;
44 with Tbuild; use Tbuild;
46 package body Exp_Smem is
48 Insert_Node : Node_Id;
49 -- Node after which a write call is to be inserted
51 -----------------------
52 -- Local Subprograms --
53 -----------------------
55 procedure Add_Read (N : Node_Id; Call : Node_Id := Empty);
56 -- Insert a Shared_Var_ROpen call for variable before node N, unless
57 -- Call is a call to an init-proc, in which case the call is inserted
58 -- after Call.
60 procedure Add_Write_After (N : Node_Id);
61 -- Insert a Shared_Var_WOpen call for variable after the node Insert_Node,
62 -- as recorded by On_Lhs_Of_Assignment (where it points to the assignment
63 -- statement) or Is_Out_Actual (where it points to the subprogram call).
64 -- When Insert_Node is a function call, establish a transient scope around
65 -- the expression, and insert the write as an after-action of the transient
66 -- scope.
68 procedure Build_Full_Name (E : Entity_Id; N : out String_Id);
69 -- Build the fully qualified string name of a shared variable
71 function On_Lhs_Of_Assignment (N : Node_Id) return Boolean;
72 -- Determines if N is on the left hand of the assignment. This means that
73 -- either it is a simple variable, or it is a record or array variable with
74 -- a corresponding selected or indexed component on the left side of an
75 -- assignment. If the result is True, then Insert_Node is set to point
76 -- to the assignment
78 function Is_Out_Actual (N : Node_Id) return Boolean;
79 -- In a similar manner, this function determines if N appears as an OUT
80 -- or IN OUT parameter to a procedure call. If the result is True, then
81 -- Insert_Node is set to point to the call.
83 function Build_Shared_Var_Proc_Call
84 (Loc : Source_Ptr;
85 E : Node_Id;
86 N : Name_Id) return Node_Id;
87 -- Build a call to support procedure N for shared object E (provided by the
88 -- instance of System.Shared_Storage.Shared_Var_Procs associated to E).
90 --------------------------------
91 -- Build_Shared_Var_Proc_Call --
92 --------------------------------
94 function Build_Shared_Var_Proc_Call
95 (Loc : Source_Ptr;
96 E : Entity_Id;
97 N : Name_Id) return Node_Id
99 begin
100 return Make_Procedure_Call_Statement (Loc,
101 Name => Make_Selected_Component (Loc,
102 Prefix =>
103 New_Occurrence_Of (Shared_Var_Procs_Instance (E), Loc),
104 Selector_Name => Make_Identifier (Loc, N)));
105 end Build_Shared_Var_Proc_Call;
107 --------------
108 -- Add_Read --
109 --------------
111 procedure Add_Read (N : Node_Id; Call : Node_Id := Empty) is
112 Loc : constant Source_Ptr := Sloc (N);
113 Ent : constant Node_Id := Entity (N);
114 SVC : Node_Id;
116 begin
117 if Present (Shared_Var_Procs_Instance (Ent)) then
118 SVC := Build_Shared_Var_Proc_Call (Loc, Ent, Name_Read);
120 if Present (Call) and then Is_Init_Proc (Name (Call)) then
121 Insert_After_And_Analyze (Call, SVC);
122 else
123 Insert_Action (N, SVC);
124 end if;
125 end if;
126 end Add_Read;
128 -------------------------------
129 -- Add_Shared_Var_Lock_Procs --
130 -------------------------------
132 procedure Add_Shared_Var_Lock_Procs (N : Node_Id) is
133 Loc : constant Source_Ptr := Sloc (N);
134 Obj : constant Entity_Id := Entity (Expression (First_Actual (N)));
135 Vnm : String_Id;
136 Vid : Entity_Id;
137 Vde : Node_Id;
138 Aft : constant List_Id := New_List;
140 In_Transient : constant Boolean := Scope_Is_Transient;
142 function Build_Shared_Var_Lock_Call (RE : RE_Id) return Node_Id;
143 -- Return a procedure call statement for lock proc RTE
145 --------------------------------
146 -- Build_Shared_Var_Lock_Call --
147 --------------------------------
149 function Build_Shared_Var_Lock_Call (RE : RE_Id) return Node_Id is
150 begin
151 return
152 Make_Procedure_Call_Statement (Loc,
153 Name =>
154 New_Occurrence_Of (RTE (RE), Loc),
155 Parameter_Associations =>
156 New_List (New_Occurrence_Of (Vid, Loc)));
157 end Build_Shared_Var_Lock_Call;
159 -- Start of processing for Add_Shared_Var_Lock_Procs
161 begin
162 -- Discussion of transient scopes: we need to have a transient scope
163 -- to hold the required lock/unlock actions. Either the current scope
164 -- is transient, in which case we reuse it, or we establish a new
165 -- transient scope. If this is a function call with unconstrained
166 -- return type, we can't introduce a transient scope here (because
167 -- Wrap_Transient_Expression would need to declare a temporary with
168 -- the unconstrained type outside of the transient block), but in that
169 -- case we know that we have already established one at an outer level
170 -- for secondary stack management purposes.
172 -- If the lock/read/write/unlock actions for this object have already
173 -- been emitted in the current scope, no need to perform them anew.
175 if In_Transient
176 and then Contains (Scope_Stack.Table (Scope_Stack.Last)
177 .Locked_Shared_Objects,
178 Obj)
179 then
180 return;
181 end if;
183 Build_Full_Name (Obj, Vnm);
185 -- Declare a constant string to hold the name of the shared object.
186 -- Note that this must occur outside of the transient scope, as the
187 -- scope's finalizer needs to have access to this object. Also, it
188 -- appears that GIGI does not support elaborating string literal
189 -- subtypes in transient scopes.
191 Vid := Make_Temporary (Loc, 'N', Obj);
192 Vde :=
193 Make_Object_Declaration (Loc,
194 Defining_Identifier => Vid,
195 Constant_Present => True,
196 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
197 Expression => Make_String_Literal (Loc, Vnm));
199 -- Already in a transient scope. Make sure that we insert Vde outside
200 -- that scope.
202 if In_Transient then
203 Insert_Before_And_Analyze (Node_To_Be_Wrapped, Vde);
205 -- Not in a transient scope yet: insert Vde as an action on N prior to
206 -- establishing one.
208 else
209 Insert_Action (N, Vde);
210 Establish_Transient_Scope (N, Manage_Sec_Stack => False);
211 end if;
213 -- Mark object as locked in the current (transient) scope
215 Append_New_Elmt
216 (Obj,
217 To => Scope_Stack.Table (Scope_Stack.Last).Locked_Shared_Objects);
219 -- First insert the Lock call before
221 Insert_Action (N, Build_Shared_Var_Lock_Call (RE_Shared_Var_Lock));
223 -- Now, right after the Lock, insert a call to read the object
225 Insert_Action (N, Build_Shared_Var_Proc_Call (Loc, Obj, Name_Read));
227 -- For a procedure call only, insert the call to write the object prior
228 -- to unlocking.
230 if Nkind (N) = N_Procedure_Call_Statement then
231 Append_To (Aft, Build_Shared_Var_Proc_Call (Loc, Obj, Name_Write));
232 end if;
234 -- Finally insert the Unlock call
236 Append_To (Aft, Build_Shared_Var_Lock_Call (RE_Shared_Var_Unlock));
238 -- Store cleanup actions in transient scope
240 Store_Cleanup_Actions_In_Scope (Aft);
242 -- If we have established a transient scope here, wrap it now
244 if not In_Transient then
245 if Nkind (N) = N_Procedure_Call_Statement then
246 Wrap_Transient_Statement (N);
247 else
248 Wrap_Transient_Expression (N);
249 end if;
250 end if;
251 end Add_Shared_Var_Lock_Procs;
253 ---------------------
254 -- Add_Write_After --
255 ---------------------
257 procedure Add_Write_After (N : Node_Id) is
258 Ent : constant Entity_Id := Entity (N);
259 Loc : constant Source_Ptr := Sloc (N);
260 Par : constant Node_Id := Insert_Node;
262 begin
263 if Present (Shared_Var_Procs_Instance (Ent)) then
264 if Nkind (Insert_Node) = N_Function_Call then
265 Establish_Transient_Scope (Insert_Node, Manage_Sec_Stack => False);
267 Store_After_Actions_In_Scope (New_List (
268 Build_Shared_Var_Proc_Call (Loc, Ent, Name_Write)));
269 else
270 Insert_After_And_Analyze (Par,
271 Build_Shared_Var_Proc_Call (Loc, Ent, Name_Write));
272 end if;
273 end if;
274 end Add_Write_After;
276 ---------------------
277 -- Build_Full_Name --
278 ---------------------
280 procedure Build_Full_Name (E : Entity_Id; N : out String_Id) is
282 procedure Build_Name (E : Entity_Id);
283 -- This is a recursive routine used to construct the fully qualified
284 -- string name of the package corresponding to the shared variable.
286 ----------------
287 -- Build_Name --
288 ----------------
290 procedure Build_Name (E : Entity_Id) is
291 begin
292 if Scope (E) /= Standard_Standard then
293 Build_Name (Scope (E));
294 Store_String_Char ('.');
295 end if;
297 Get_Decoded_Name_String (Chars (E));
298 Store_String_Chars (Name_Buffer (1 .. Name_Len));
299 end Build_Name;
301 -- Start of processing for Build_Full_Name
303 begin
304 Start_String;
305 Build_Name (E);
306 N := End_String;
307 end Build_Full_Name;
309 ------------------------------------
310 -- Expand_Shared_Passive_Variable --
311 ------------------------------------
313 procedure Expand_Shared_Passive_Variable (N : Node_Id) is
314 Typ : constant Entity_Id := Etype (N);
316 begin
317 -- Nothing to do for protected or limited objects
319 if Is_Limited_Type (Typ) or else Is_Concurrent_Type (Typ) then
320 return;
322 -- If we are on the left hand side of an assignment, then we add the
323 -- write call after the assignment.
325 elsif On_Lhs_Of_Assignment (N) then
326 Add_Write_After (N);
328 -- If we are a parameter for an out or in out formal, then in general
329 -- we do:
331 -- read
332 -- call
333 -- write
335 -- but in the special case of a call to an init proc, we need to first
336 -- call the init proc (to set discriminants), then read (to possibly
337 -- set other components), then write (to record the updated components
338 -- to the backing store):
340 -- init-proc-call
341 -- read
342 -- write
344 elsif Is_Out_Actual (N) then
346 -- Note: For an init proc call, Add_Read inserts just after the
347 -- call node, and we want to have first the read, then the write,
348 -- so we need to first Add_Write_After, then Add_Read.
350 Add_Write_After (N);
351 Add_Read (N, Call => Insert_Node);
353 -- All other cases are simple reads
355 else
356 Add_Read (N);
357 end if;
358 end Expand_Shared_Passive_Variable;
360 -------------------
361 -- Is_Out_Actual --
362 -------------------
364 function Is_Out_Actual (N : Node_Id) return Boolean is
365 Formal : Entity_Id;
366 Call : Node_Id;
368 begin
369 Find_Actual (N, Formal, Call);
371 if No (Formal) then
372 return False;
374 else
375 if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter) then
376 Insert_Node := Call;
377 return True;
378 else
379 return False;
380 end if;
381 end if;
382 end Is_Out_Actual;
384 ---------------------------
385 -- Make_Shared_Var_Procs --
386 ---------------------------
388 function Make_Shared_Var_Procs (N : Node_Id) return Node_Id is
389 Loc : constant Source_Ptr := Sloc (N);
390 Ent : constant Entity_Id := Defining_Identifier (N);
391 Typ : constant Entity_Id := Etype (Ent);
392 Vnm : String_Id;
393 Obj : Node_Id;
394 Obj_Typ : Entity_Id;
396 After : constant Node_Id := Next (N);
397 -- Node located right after N originally (after insertion of the SV
398 -- procs this node is right after the last inserted node).
400 SVP_Instance : constant Entity_Id := Make_Defining_Identifier (Loc,
401 Chars => New_External_Name (Chars (Ent), 'G'));
402 -- Instance of Shared_Storage.Shared_Var_Procs associated with Ent
404 Instantiation : Node_Id;
405 -- Package instantiation node for SVP_Instance
407 -- Start of processing for Make_Shared_Var_Procs
409 begin
410 Build_Full_Name (Ent, Vnm);
412 -- We turn off Shared_Passive during construction and analysis of the
413 -- generic package instantiation, to avoid improper attempts to process
414 -- the variable references within these instantiation.
416 Set_Is_Shared_Passive (Ent, False);
418 -- Construct generic package instantiation
420 -- package varG is new Shared_Var_Procs (typ, var, "pkg.var");
422 Obj := New_Occurrence_Of (Ent, Loc);
423 Obj_Typ := Typ;
424 if Is_Concurrent_Type (Typ) then
425 Obj := Convert_Concurrent (N => Obj, Typ => Typ);
426 Obj_Typ := Corresponding_Record_Type (Typ);
427 end if;
429 Instantiation :=
430 Make_Package_Instantiation (Loc,
431 Defining_Unit_Name => SVP_Instance,
432 Name =>
433 New_Occurrence_Of (RTE (RE_Shared_Var_Procs), Loc),
434 Generic_Associations => New_List (
435 Make_Generic_Association (Loc,
436 Explicit_Generic_Actual_Parameter =>
437 New_Occurrence_Of (Obj_Typ, Loc)),
438 Make_Generic_Association (Loc,
439 Explicit_Generic_Actual_Parameter => Obj),
440 Make_Generic_Association (Loc,
441 Explicit_Generic_Actual_Parameter =>
442 Make_String_Literal (Loc, Vnm))));
444 Insert_After_And_Analyze (N, Instantiation);
446 Set_Is_Shared_Passive (Ent, True);
447 Set_Shared_Var_Procs_Instance
448 (Ent, Defining_Entity (Instance_Spec (Instantiation)));
450 -- Return last node before After
452 declare
453 Nod : Node_Id := Next (N);
455 begin
456 while Next (Nod) /= After loop
457 Nod := Next (Nod);
458 end loop;
460 return Nod;
461 end;
462 end Make_Shared_Var_Procs;
464 --------------------------
465 -- On_Lhs_Of_Assignment --
466 --------------------------
468 function On_Lhs_Of_Assignment (N : Node_Id) return Boolean is
469 P : constant Node_Id := Parent (N);
471 begin
472 if Nkind (P) = N_Assignment_Statement then
473 if N = Name (P) then
474 Insert_Node := P;
475 return True;
476 else
477 return False;
478 end if;
480 elsif Nkind_In (P, N_Indexed_Component, N_Selected_Component)
481 and then N = Prefix (P)
482 then
483 return On_Lhs_Of_Assignment (P);
485 else
486 return False;
487 end if;
488 end On_Lhs_Of_Assignment;
490 end Exp_Smem;