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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- L I B . X R E F . S P A R K _ S P E C I F I C --
-- --
-- B o d y --
-- --
-- Copyright (C) 2011-2024, 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. --
-- --
------------------------------------------------------------------------------
with Einfo.Entities; use Einfo.Entities;
with Nmake; use Nmake;
with SPARK_Xrefs; use SPARK_Xrefs;
separate (Lib.Xref)
package body SPARK_Specific is
---------------------
-- Local Constants --
---------------------
-- Table of SPARK_Entities, True for each entity kind used in SPARK
SPARK_Entities : constant array (Entity_Kind) of Boolean :=
(E_Constant => True,
E_Entry => True,
E_Function => True,
E_In_Out_Parameter => True,
E_In_Parameter => True,
E_Loop_Parameter => True,
E_Operator => True,
E_Out_Parameter => True,
E_Procedure => True,
E_Variable => True,
others => False);
-- True for each reference type used in SPARK
SPARK_References : constant array (Character) of Boolean :=
('m' => True,
'r' => True,
's' => True,
others => False);
---------------------
-- Local Variables --
---------------------
package Drefs is new Table.Table (
Table_Component_Type => Xref_Entry,
Table_Index_Type => Xref_Entry_Number,
Table_Low_Bound => 1,
Table_Initial => Alloc.Drefs_Initial,
Table_Increment => Alloc.Drefs_Increment,
Table_Name => "Drefs");
-- Table of cross-references for reads and writes through explicit
-- dereferences, that are output as reads/writes to the special variable
-- "Heap". These references are added to the regular references when
-- computing SPARK cross-references.
-------------------------
-- Iterate_SPARK_Xrefs --
-------------------------
procedure Iterate_SPARK_Xrefs is
procedure Add_SPARK_Xref (Index : Int; Xref : Xref_Entry);
function Is_SPARK_Reference
(E : Entity_Id;
Typ : Character) return Boolean;
-- Return whether entity reference E meets SPARK requirements. Typ is
-- the reference type.
function Is_SPARK_Scope (E : Entity_Id) return Boolean;
-- Return whether the entity or reference scope meets requirements for
-- being a SPARK scope.
--------------------
-- Add_SPARK_Xref --
--------------------
procedure Add_SPARK_Xref (Index : Int; Xref : Xref_Entry) is
Ref : Xref_Key renames Xref.Key;
begin
-- Eliminate entries not appropriate for SPARK
if SPARK_Entities (Ekind (Ref.Ent))
and then SPARK_References (Ref.Typ)
and then Is_SPARK_Scope (Ref.Ent_Scope)
and then Is_SPARK_Scope (Ref.Ref_Scope)
and then Is_SPARK_Reference (Ref.Ent, Ref.Typ)
then
Process
(Index,
(Entity => Ref.Ent,
Ref_Scope => Ref.Ref_Scope,
Rtype => Ref.Typ));
end if;
end Add_SPARK_Xref;
------------------------
-- Is_SPARK_Reference --
------------------------
function Is_SPARK_Reference
(E : Entity_Id;
Typ : Character) return Boolean
is
begin
-- The only references of interest on callable entities are calls. On
-- uncallable entities, the only references of interest are reads and
-- writes.
if Ekind (E) in Overloadable_Kind then
return Typ = 's';
-- In all other cases, result is true for reference/modify cases,
-- and false for all other cases.
else
return Typ = 'r' or else Typ = 'm';
end if;
end Is_SPARK_Reference;
--------------------
-- Is_SPARK_Scope --
--------------------
function Is_SPARK_Scope (E : Entity_Id) return Boolean is
Can_Be_Renamed : constant Boolean :=
Present (E)
and then (Is_Subprogram_Or_Entry (E)
or else Ekind (E) = E_Package);
begin
return Present (E)
and then not Is_Generic_Unit (E)
and then (not Can_Be_Renamed or else No (Renamed_Entity (E)));
end Is_SPARK_Scope;
-- Start of processing for Add_SPARK_Xrefs
begin
-- Expose cross-references from private frontend tables to the backend
for Index in Drefs.First .. Drefs.Last loop
Add_SPARK_Xref (Index, Drefs.Table (Index));
end loop;
for Index in Xrefs.First .. Xrefs.Last loop
Add_SPARK_Xref (-Index, Xrefs.Table (Index));
end loop;
end Iterate_SPARK_Xrefs;
---------------------------------------------
-- Enclosing_Subprogram_Or_Library_Package --
---------------------------------------------
function Enclosing_Subprogram_Or_Library_Package
(N : Node_Id) return Entity_Id
is
Context : Entity_Id;
begin
-- If N is the defining identifier for a subprogram, then return the
-- enclosing subprogram or package, not this subprogram.
if Nkind (N) in N_Defining_Identifier | N_Defining_Operator_Symbol
and then Ekind (N) in Entry_Kind
| E_Subprogram_Body
| Generic_Subprogram_Kind
| Subprogram_Kind
then
if No (Unit_Declaration_Node (N)) then
return Empty;
end if;
Context := Parent (Unit_Declaration_Node (N));
-- If this was a library-level subprogram then replace Context with
-- its Unit, which points to N_Subprogram_* node.
if Nkind (Context) = N_Compilation_Unit then
Context := Unit (Context);
end if;
else
Context := N;
end if;
while Present (Context) loop
case Nkind (Context) is
when N_Package_Body
| N_Package_Specification
=>
-- Only return a library-level package
if Is_Library_Level_Entity (Defining_Entity (Context)) then
Context := Defining_Entity (Context);
exit;
else
Context := Parent (Context);
end if;
when N_Pragma =>
-- The enclosing subprogram for a precondition, postcondition,
-- or contract case should be the declaration preceding the
-- pragma (skipping any other pragmas between this pragma and
-- this declaration.
while Nkind (Context) = N_Pragma
and then Is_List_Member (Context)
and then Present (Prev (Context))
loop
Context := Prev (Context);
end loop;
if Nkind (Context) = N_Pragma then
-- When used for cross-references then aspects might not be
-- yet linked to pragmas; when used for AST navigation in
-- GNATprove this routine is expected to follow those links.
if From_Aspect_Specification (Context) then
Context := Corresponding_Aspect (Context);
pragma Assert (Nkind (Context) = N_Aspect_Specification);
Context := Entity (Context);
else
Context := Parent (Context);
end if;
end if;
when N_Entry_Body
| N_Entry_Declaration
| N_Protected_Type_Declaration
| N_Subprogram_Body
| N_Subprogram_Declaration
| N_Subprogram_Specification
| N_Task_Body
| N_Task_Type_Declaration
=>
Context := Defining_Entity (Context);
exit;
when others =>
Context := Parent (Context);
end case;
end loop;
if Nkind (Context) = N_Defining_Program_Unit_Name then
Context := Defining_Identifier (Context);
end if;
-- Do not return a scope without a proper location
if Present (Context)
and then Sloc (Context) = No_Location
then
return Empty;
end if;
return Context;
end Enclosing_Subprogram_Or_Library_Package;
--------------------------
-- Generate_Dereference --
--------------------------
procedure Generate_Dereference
(N : Node_Id;
Typ : Character := 'r')
is
procedure Create_Heap;
-- Create and decorate the special entity which denotes the heap
-----------------
-- Create_Heap --
-----------------
procedure Create_Heap is
begin
Heap :=
Make_Defining_Identifier
(Standard_Location,
Name_Enter (Name_Of_Heap_Variable));
Mutate_Ekind (Heap, E_Variable);
Set_Is_Internal (Heap, True);
Set_Etype (Heap, Standard_Void_Type);
Set_Scope (Heap, Standard_Standard);
Set_Has_Fully_Qualified_Name (Heap);
end Create_Heap;
-- Local variables
Loc : constant Source_Ptr := Sloc (N);
-- Start of processing for Generate_Dereference
begin
if Loc > No_Location then
Drefs.Increment_Last;
declare
Deref_Entry : Xref_Entry renames Drefs.Table (Drefs.Last);
Deref : Xref_Key renames Deref_Entry.Key;
begin
if No (Heap) then
Create_Heap;
end if;
Deref.Ent := Heap;
Deref.Loc := Loc;
Deref.Typ := Typ;
-- It is as if the special "Heap" was defined in the main unit,
-- in the scope of the entity for the main unit. This single
-- definition point is required to ensure that sorting cross
-- references works for "Heap" references as well.
Deref.Eun := Main_Unit;
Deref.Lun := Get_Top_Level_Code_Unit (Loc);
Deref.Ref_Scope := Enclosing_Subprogram_Or_Library_Package (N);
Deref.Ent_Scope := Cunit_Entity (Main_Unit);
Deref_Entry.Def := No_Location;
Deref_Entry.Ent_Scope_File := Main_Unit;
end;
end if;
end Generate_Dereference;
end SPARK_Specific;
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