------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S T R U B -- -- -- -- B o d y -- -- -- -- Copyright (C) 2021-2022, 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. -- -- -- ------------------------------------------------------------------------------ -- Package containing utility procedures related to Stack Scrubbing with Atree; use Atree; with Einfo; use Einfo; with Einfo.Entities; use Einfo.Entities; with Errout; use Errout; with Namet; use Namet; with Nlists; use Nlists; with Sem_Eval; use Sem_Eval; with Sinfo; use Sinfo; with Sinfo.Nodes; use Sinfo.Nodes; with Sinfo.Utils; use Sinfo.Utils; with Snames; use Snames; with Stringt; use Stringt; package body Strub is ----------------------- -- Local Subprograms -- ----------------------- function Find_Explicit_Strub_Pragma (Id : Entity_Id) return Node_Id; -- Return a pragma Machine_Attribute (Id, "strub"[, "mode"]) node -- if Id has one. function Strub_Pragma_Arg (Item : Node_Id) return Node_Id is (Get_Pragma_Arg (Next (Next (First (Pragma_Argument_Associations (Item)))))); -- Return the pragma argument holding the strub mode associated -- with Item, a subprogram, variable, constant, or type. Bear in -- mind that strub pragmas with an explicit strub mode argument, -- naming access-to-subprogram types, are applied to the -- designated subprogram type. function Strub_Pragma_Arg_To_String (Item : Node_Id) return String is (To_String (Strval (Expr_Value_S (Item)))); -- Extract and return as a String the strub mode held in a node -- returned by Strub_Pragma_Arg. function Strub_Pragma_Mode (Id : Entity_Id; Item : Node_Id) return Strub_Mode; -- Return the strub mode associated with Item expressed in Id. -- Strub_Pragma_P (Id) must hold. --------------------------- -- Check_Same_Strub_Mode -- --------------------------- procedure Check_Same_Strub_Mode (Dest, Src : Entity_Id; Report : Boolean := True) is Src_Strub_Mode : constant Strub_Mode := Explicit_Strub_Mode (Src); Dest_Strub_Mode : constant Strub_Mode := Explicit_Strub_Mode (Dest); begin if Dest_Strub_Mode = Src_Strub_Mode then return; end if; -- Internal is not part of the interface, it's an *internal* -- implementation detail, so consider it equivalent to unspecified here. -- ??? -fstrub=relaxed|strict makes them interface-equivalent to -- Callable or Disabled, respectively, but we don't look at that flag in -- the front-end, and it seems undesirable for that flag to affect -- whether specifications are conformant. Maybe there should be some -- means to specify Callable or Disabled along with Internal? if Dest_Strub_Mode in Unspecified | Internal and then Src_Strub_Mode in Unspecified | Internal then return; end if; if not Report then return; end if; if Src_Strub_Mode /= Unspecified then Error_Msg_Sloc := Sloc (Find_Explicit_Strub_Pragma (Src)); else Error_Msg_Sloc := Sloc (Src); end if; Error_Msg_Node_2 := Src; Error_Msg_NE ("& requires the same `strub` mode as &#", (if Dest_Strub_Mode /= Unspecified then Find_Explicit_Strub_Pragma (Dest) else Dest), Dest); end Check_Same_Strub_Mode; ---------------------------- -- Compatible_Strub_Modes -- ---------------------------- function Compatible_Strub_Modes (Dest, Src : Entity_Id) return Boolean is Src_Strub_Mode : constant Strub_Mode := Explicit_Strub_Mode (Src); Dest_Strub_Mode : constant Strub_Mode := Explicit_Strub_Mode (Dest); begin return Src_Strub_Mode = Dest_Strub_Mode or else At_Calls not in Src_Strub_Mode | Dest_Strub_Mode; end Compatible_Strub_Modes; --------------------- -- Copy_Strub_Mode -- --------------------- procedure Copy_Strub_Mode (Dest, Src : Entity_Id) is Strub : Node_Id := Find_Explicit_Strub_Pragma (Src); Src_Strub_Mode : constant Strub_Mode := Strub_Pragma_Mode (Src, Strub); begin pragma Assert (Explicit_Strub_Mode (Dest) = Unspecified); -- Refrain from copying Internal to subprogram types. -- It affects code generation for the subprogram, -- but it has no effect on its type or interface. if Src_Strub_Mode = Unspecified or else (Ekind (Dest) = E_Subprogram_Type and then Src_Strub_Mode = Internal) then return; end if; Strub := New_Copy (Strub); Set_Next_Rep_Item (Strub, First_Rep_Item (Dest)); Set_First_Rep_Item (Dest, Strub); Set_Has_Gigi_Rep_Item (Dest); end Copy_Strub_Mode; ------------------------- -- Explicit_Strub_Mode -- ------------------------- function Explicit_Strub_Mode (Id : Entity_Id) return Strub_Mode is Item : constant Node_Id := Find_Explicit_Strub_Pragma (Id); begin return Strub_Pragma_Mode (Id, Item); end Explicit_Strub_Mode; -------------------------------- -- Find_Explicit_Strub_Pragma -- -------------------------------- function Find_Explicit_Strub_Pragma (Id : Entity_Id) return Node_Id is Item : Node_Id; begin if not Has_Gigi_Rep_Item (Id) then return Empty; end if; Item := First_Rep_Item (Id); while Present (Item) loop if Strub_Pragma_P (Item) then return Item; end if; Item := Next_Rep_Item (Item); end loop; return Empty; end Find_Explicit_Strub_Pragma; ----------------------- -- Strub_Pragma_Mode -- ----------------------- function Strub_Pragma_Mode (Id : Entity_Id; Item : Node_Id) return Strub_Mode is Arg : Node_Id := Empty; begin -- ??? Enumeration literals, despite being conceptually functions, have -- neither bodies nor stack frames, and it's not clear whether it would -- make more sense to treat them as subprograms or as constants, but -- they can be renamed as functions. Should we require all literals of -- a type to have the same strub mode? Rule out their annotation? if Ekind (Id) in E_Subprogram_Type | Overloadable_Kind | Generic_Subprogram_Kind then if Item = Empty then return Unspecified; end if; Arg := Strub_Pragma_Arg (Item); if Arg = Empty then return At_Calls; end if; declare Str : constant String := Strub_Pragma_Arg_To_String (Arg); begin if Str'Length /= 8 then return Unspecified; end if; case Str (Str'First) is when 'a' => if Str = "at-calls" then return At_Calls; end if; when 'i' => if Str = "internal" then return Internal; end if; when 'c' => if Str = "callable" then return Callable; end if; when 'd' => if Str = "disabled" then return Disabled; end if; when others => null; end case; return Unspecified; end; -- Access-to-subprogram types and variables can be treated just like -- other access types, because the pragma logic has already promoted to -- subprogram types any annotations applicable to them. elsif Ekind (Id) in Type_Kind -- except E_Subprogram_Type, covered above | Scalar_Kind | Object_Kind | Named_Kind then if Item = Empty then return Unspecified; end if; Arg := Strub_Pragma_Arg (Item); if Arg /= Empty then -- A strub parameter is not applicable to variables, -- and will be ignored. return Unspecified; end if; return Enabled; else pragma Assert (Item = Empty); return Not_Applicable; end if; end Strub_Pragma_Mode; -------------------- -- Strub_Pragma_P -- -------------------- function Strub_Pragma_P (Item : Node_Id) return Boolean is (Nkind (Item) = N_Pragma and then Pragma_Name (Item) = Name_Machine_Attribute and then Strub_Pragma_Arg_To_String (Get_Pragma_Arg (Next (First (Pragma_Argument_Associations (Item))))) = "strub"); end Strub;