------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ S M E M -- -- -- -- B o d y -- -- -- -- Copyright (C) 1998-2013, 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 Atree; use Atree; with Einfo; use Einfo; with Exp_Ch7; use Exp_Ch7; with Exp_Ch9; use Exp_Ch9; with Exp_Tss; use Exp_Tss; with Exp_Util; use Exp_Util; with Nmake; use Nmake; with Namet; use Namet; with Nlists; use Nlists; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Snames; use Snames; with Stand; use Stand; with Stringt; use Stringt; with Tbuild; use Tbuild; package body Exp_Smem is Insert_Node : Node_Id; -- Node after which a write call is to be inserted ----------------------- -- Local Subprograms -- ----------------------- procedure Add_Read (N : Node_Id; Call : Node_Id := Empty); -- Insert a Shared_Var_ROpen call for variable before node N, unless -- Call is a call to an init-proc, in which case the call is inserted -- after Call. procedure Add_Write_After (N : Node_Id); -- Insert a Shared_Var_WOpen call for variable after the node Insert_Node, -- as recorded by On_Lhs_Of_Assignment (where it points to the assignment -- statement) or Is_Out_Actual (where it points to the subprogram call). -- When Insert_Node is a function call, establish a transient scope around -- the expression, and insert the write as an after-action of the transient -- scope. procedure Build_Full_Name (E : Entity_Id; N : out String_Id); -- Build the fully qualified string name of a shared variable function On_Lhs_Of_Assignment (N : Node_Id) return Boolean; -- Determines if N is on the left hand of the assignment. This means that -- either it is a simple variable, or it is a record or array variable with -- a corresponding selected or indexed component on the left side of an -- assignment. If the result is True, then Insert_Node is set to point -- to the assignment function Is_Out_Actual (N : Node_Id) return Boolean; -- In a similar manner, this function determines if N appears as an OUT -- or IN OUT parameter to a procedure call. If the result is True, then -- Insert_Node is set to point to the call. function Build_Shared_Var_Proc_Call (Loc : Source_Ptr; E : Node_Id; N : Name_Id) return Node_Id; -- Build a call to support procedure N for shared object E (provided by the -- instance of System.Shared_Storage.Shared_Var_Procs associated to E). -------------------------------- -- Build_Shared_Var_Proc_Call -- -------------------------------- function Build_Shared_Var_Proc_Call (Loc : Source_Ptr; E : Entity_Id; N : Name_Id) return Node_Id is begin return Make_Procedure_Call_Statement (Loc, Name => Make_Selected_Component (Loc, Prefix => New_Occurrence_Of (Shared_Var_Procs_Instance (E), Loc), Selector_Name => Make_Identifier (Loc, N))); end Build_Shared_Var_Proc_Call; -------------- -- Add_Read -- -------------- procedure Add_Read (N : Node_Id; Call : Node_Id := Empty) is Loc : constant Source_Ptr := Sloc (N); Ent : constant Node_Id := Entity (N); SVC : Node_Id; begin if Present (Shared_Var_Procs_Instance (Ent)) then SVC := Build_Shared_Var_Proc_Call (Loc, Ent, Name_Read); if Present (Call) and then Is_Init_Proc (Name (Call)) then Insert_After_And_Analyze (Call, SVC); else Insert_Action (N, SVC); end if; end if; end Add_Read; ------------------------------- -- Add_Shared_Var_Lock_Procs -- ------------------------------- procedure Add_Shared_Var_Lock_Procs (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Obj : constant Entity_Id := Entity (Expression (First_Actual (N))); Inode : Node_Id; Vnm : String_Id; begin -- We have to add Shared_Var_Lock and Shared_Var_Unlock calls around -- the procedure or function call node. First we locate the right place -- to do the insertion, which is the call itself in the procedure call -- case, or else the nearest non subexpression node that contains the -- function call. Inode := N; while Nkind (Inode) /= N_Procedure_Call_Statement and then Nkind (Inode) in N_Subexpr loop Inode := Parent (Inode); end loop; -- Now insert the Lock and Unlock calls and the read/write calls -- Two concerns here. First we are not dealing with the exception case, -- really we need some kind of cleanup routine to do the Unlock. Second, -- these lock calls should be inside the protected object processing, -- not outside, otherwise they can be done at the wrong priority, -- resulting in dead lock situations ??? Build_Full_Name (Obj, Vnm); -- First insert the Lock call before Insert_Before_And_Analyze (Inode, Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Shared_Var_Lock), Loc), Parameter_Associations => New_List ( Make_String_Literal (Loc, Vnm)))); -- Now, right after the Lock, insert a call to read the object Insert_Before_And_Analyze (Inode, Build_Shared_Var_Proc_Call (Loc, Obj, Name_Read)); -- Now insert the Unlock call after Insert_After_And_Analyze (Inode, Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Shared_Var_Unlock), Loc), Parameter_Associations => New_List ( Make_String_Literal (Loc, Vnm)))); -- Now for a procedure call, but not a function call, insert the -- call to write the object just before the unlock. if Nkind (N) = N_Procedure_Call_Statement then Insert_After_And_Analyze (Inode, Build_Shared_Var_Proc_Call (Loc, Obj, Name_Write)); end if; end Add_Shared_Var_Lock_Procs; --------------------- -- Add_Write_After -- --------------------- procedure Add_Write_After (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Ent : constant Entity_Id := Entity (N); Par : constant Node_Id := Insert_Node; begin if Present (Shared_Var_Procs_Instance (Ent)) then if Nkind (Insert_Node) = N_Function_Call then Establish_Transient_Scope (Insert_Node, Sec_Stack => False); Store_After_Actions_In_Scope (New_List ( Build_Shared_Var_Proc_Call (Loc, Ent, Name_Write))); else Insert_After_And_Analyze (Par, Build_Shared_Var_Proc_Call (Loc, Ent, Name_Write)); end if; end if; end Add_Write_After; --------------------- -- Build_Full_Name -- --------------------- procedure Build_Full_Name (E : Entity_Id; N : out String_Id) is procedure Build_Name (E : Entity_Id); -- This is a recursive routine used to construct the fully qualified -- string name of the package corresponding to the shared variable. ---------------- -- Build_Name -- ---------------- procedure Build_Name (E : Entity_Id) is begin if Scope (E) /= Standard_Standard then Build_Name (Scope (E)); Store_String_Char ('.'); end if; Get_Decoded_Name_String (Chars (E)); Store_String_Chars (Name_Buffer (1 .. Name_Len)); end Build_Name; -- Start of processing for Build_Full_Name begin Start_String; Build_Name (E); N := End_String; end Build_Full_Name; ------------------------------------ -- Expand_Shared_Passive_Variable -- ------------------------------------ procedure Expand_Shared_Passive_Variable (N : Node_Id) is Typ : constant Entity_Id := Etype (N); begin -- Nothing to do for protected or limited objects if Is_Limited_Type (Typ) or else Is_Concurrent_Type (Typ) then return; -- If we are on the left hand side of an assignment, then we add the -- write call after the assignment. elsif On_Lhs_Of_Assignment (N) then Add_Write_After (N); -- If we are a parameter for an out or in out formal, then in general -- we do: -- read -- call -- write -- but in the special case of a call to an init proc, we need to first -- call the init proc (to set discriminants), then read (to possibly -- set other components), then write (to record the updated components -- to the backing store): -- init-proc-call -- read -- write elsif Is_Out_Actual (N) then -- Note: For an init proc call, Add_Read inserts just after the -- call node, and we want to have first the read, then the write, -- so we need to first Add_Write_After, then Add_Read. Add_Write_After (N); Add_Read (N, Call => Insert_Node); -- All other cases are simple reads else Add_Read (N); end if; end Expand_Shared_Passive_Variable; ------------------- -- Is_Out_Actual -- ------------------- function Is_Out_Actual (N : Node_Id) return Boolean is Formal : Entity_Id; Call : Node_Id; begin Find_Actual (N, Formal, Call); if No (Formal) then return False; else if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter) then Insert_Node := Call; return True; else return False; end if; end if; end Is_Out_Actual; --------------------------- -- Make_Shared_Var_Procs -- --------------------------- function Make_Shared_Var_Procs (N : Node_Id) return Node_Id is Loc : constant Source_Ptr := Sloc (N); Ent : constant Entity_Id := Defining_Identifier (N); Typ : constant Entity_Id := Etype (Ent); Vnm : String_Id; Obj : Node_Id; Obj_Typ : Entity_Id; After : constant Node_Id := Next (N); -- Node located right after N originally (after insertion of the SV -- procs this node is right after the last inserted node). SVP_Instance : constant Entity_Id := Make_Defining_Identifier (Loc, Chars => New_External_Name (Chars (Ent), 'G')); -- Instance of Shared_Storage.Shared_Var_Procs associated with Ent Instantiation : Node_Id; -- Package instantiation node for SVP_Instance -- Start of processing for Make_Shared_Var_Procs begin Build_Full_Name (Ent, Vnm); -- We turn off Shared_Passive during construction and analysis of the -- generic package instantiation, to avoid improper attempts to process -- the variable references within these instantiation. Set_Is_Shared_Passive (Ent, False); -- Construct generic package instantiation -- package varG is new Shared_Var_Procs (typ, var, "pkg.var"); Obj := New_Occurrence_Of (Ent, Loc); Obj_Typ := Typ; if Is_Concurrent_Type (Typ) then Obj := Convert_Concurrent (N => Obj, Typ => Typ); Obj_Typ := Corresponding_Record_Type (Typ); end if; Instantiation := Make_Package_Instantiation (Loc, Defining_Unit_Name => SVP_Instance, Name => New_Occurrence_Of (RTE (RE_Shared_Var_Procs), Loc), Generic_Associations => New_List ( Make_Generic_Association (Loc, Explicit_Generic_Actual_Parameter => New_Occurrence_Of (Obj_Typ, Loc)), Make_Generic_Association (Loc, Explicit_Generic_Actual_Parameter => Obj), Make_Generic_Association (Loc, Explicit_Generic_Actual_Parameter => Make_String_Literal (Loc, Vnm)))); Insert_After_And_Analyze (N, Instantiation); Set_Is_Shared_Passive (Ent, True); Set_Shared_Var_Procs_Instance (Ent, Defining_Entity (Instance_Spec (Instantiation))); -- Return last node before After declare Nod : Node_Id := Next (N); begin while Next (Nod) /= After loop Nod := Next (Nod); end loop; return Nod; end; end Make_Shared_Var_Procs; -------------------------- -- On_Lhs_Of_Assignment -- -------------------------- function On_Lhs_Of_Assignment (N : Node_Id) return Boolean is P : constant Node_Id := Parent (N); begin if Nkind (P) = N_Assignment_Statement then if N = Name (P) then Insert_Node := P; return True; else return False; end if; elsif Nkind_In (P, N_Indexed_Component, N_Selected_Component) and then N = Prefix (P) then return On_Lhs_Of_Assignment (P); else return False; end if; end On_Lhs_Of_Assignment; end Exp_Smem;