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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ C H 6 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2012, 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 Checks; use Checks; with Debug; use Debug; with Einfo; use Einfo; with Errout; use Errout; with Elists; use Elists; with Exp_Aggr; use Exp_Aggr; with Exp_Atag; use Exp_Atag; with Exp_Ch2; use Exp_Ch2; with Exp_Ch3; use Exp_Ch3; with Exp_Ch7; use Exp_Ch7; with Exp_Ch9; use Exp_Ch9; with Exp_Dbug; use Exp_Dbug; with Exp_Disp; use Exp_Disp; with Exp_Dist; use Exp_Dist; with Exp_Intr; use Exp_Intr; with Exp_Pakd; use Exp_Pakd; with Exp_Tss; use Exp_Tss; with Exp_Util; use Exp_Util; with Exp_VFpt; use Exp_VFpt; with Fname; use Fname; with Freeze; use Freeze; with Inline; use Inline; with Lib; use Lib; with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Ch6; use Sem_Ch6; with Sem_Ch8; use Sem_Ch8; with Sem_Ch12; use Sem_Ch12; with Sem_Ch13; use Sem_Ch13; with Sem_Dim; use Sem_Dim; with Sem_Disp; use Sem_Disp; with Sem_Dist; use Sem_Dist; with Sem_Eval; use Sem_Eval; with Sem_Mech; use Sem_Mech; with Sem_Res; use Sem_Res; with Sem_SCIL; use Sem_SCIL; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Snames; use Snames; with Stand; use Stand; with Targparm; use Targparm; with Tbuild; use Tbuild; with Uintp; use Uintp; with Validsw; use Validsw; package body Exp_Ch6 is ----------------------- -- Local Subprograms -- ----------------------- procedure Add_Access_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Return_Object : Node_Id; Is_Access : Boolean := False); -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the -- object name given by Return_Object and add the attribute to the end of -- the actual parameter list associated with the build-in-place function -- call denoted by Function_Call. However, if Is_Access is True, then -- Return_Object is already an access expression, in which case it's passed -- along directly to the build-in-place function. Finally, if Return_Object -- is empty, then pass a null literal as the actual. procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Alloc_Form : BIP_Allocation_Form := Unspecified; Alloc_Form_Exp : Node_Id := Empty; Pool_Actual : Node_Id := Make_Null (No_Location)); -- Ada 2005 (AI-318-02): Add the actuals needed for a build-in-place -- function call that returns a caller-unknown-size result (BIP_Alloc_Form -- and BIP_Storage_Pool). If Alloc_Form_Exp is present, then use it, -- otherwise pass a literal corresponding to the Alloc_Form parameter -- (which must not be Unspecified in that case). Pool_Actual is the -- parameter to pass to BIP_Storage_Pool. procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call : Node_Id; Func_Id : Entity_Id; Ptr_Typ : Entity_Id := Empty; Master_Exp : Node_Id := Empty); -- Ada 2005 (AI-318-02): If the result type of a build-in-place call needs -- finalization actions, add an actual parameter which is a pointer to the -- finalization master of the caller. If Master_Exp is not Empty, then that -- will be passed as the actual. Otherwise, if Ptr_Typ is left Empty, this -- will result in an automatic "null" value for the actual. procedure Add_Task_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Master_Actual : Node_Id); -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type -- contains tasks, add two actual parameters: the master, and a pointer to -- the caller's activation chain. Master_Actual is the actual parameter -- expression to pass for the master. In most cases, this is the current -- master (_master). The two exceptions are: If the function call is the -- initialization expression for an allocator, we pass the master of the -- access type. If the function call is the initialization expression for a -- return object, we pass along the master passed in by the caller. The -- activation chain to pass is always the local one. Note: Master_Actual -- can be Empty, but only if there are no tasks. procedure Check_Overriding_Operation (Subp : Entity_Id); -- Subp is a dispatching operation. Check whether it may override an -- inherited private operation, in which case its DT entry is that of -- the hidden operation, not the one it may have received earlier. -- This must be done before emitting the code to set the corresponding -- DT to the address of the subprogram. The actual placement of Subp in -- the proper place in the list of primitive operations is done in -- Declare_Inherited_Private_Subprograms, which also has to deal with -- implicit operations. This duplication is unavoidable for now??? procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id); -- This procedure is called only if the subprogram body N, whose spec -- has the given entity Spec, contains a parameterless recursive call. -- It attempts to generate runtime code to detect if this a case of -- infinite recursion. -- -- The body is scanned to determine dependencies. If the only external -- dependencies are on a small set of scalar variables, then the values -- of these variables are captured on entry to the subprogram, and if -- the values are not changed for the call, we know immediately that -- we have an infinite recursion. procedure Expand_Ctrl_Function_Call (N : Node_Id); -- N is a function call which returns a controlled object. Transform the -- call into a temporary which retrieves the returned object from the -- secondary stack using 'reference. procedure Expand_Inlined_Call (N : Node_Id; Subp : Entity_Id; Orig_Subp : Entity_Id); -- If called subprogram can be inlined by the front-end, retrieve the -- analyzed body, replace formals with actuals and expand call in place. -- Generate thunks for actuals that are expressions, and insert the -- corresponding constant declarations before the call. If the original -- call is to a derived operation, the return type is the one of the -- derived operation, but the body is that of the original, so return -- expressions in the body must be converted to the desired type (which -- is simply not noted in the tree without inline expansion). procedure Expand_Non_Function_Return (N : Node_Id); -- Called by Expand_N_Simple_Return_Statement in case we're returning from -- a procedure body, entry body, accept statement, or extended return -- statement. Note that all non-function returns are simple return -- statements. function Expand_Protected_Object_Reference (N : Node_Id; Scop : Entity_Id) return Node_Id; procedure Expand_Protected_Subprogram_Call (N : Node_Id; Subp : Entity_Id; Scop : Entity_Id); -- A call to a protected subprogram within the protected object may appear -- as a regular call. The list of actuals must be expanded to contain a -- reference to the object itself, and the call becomes a call to the -- corresponding protected subprogram. function Has_Unconstrained_Access_Discriminants (Subtyp : Entity_Id) return Boolean; -- Returns True if the given subtype is unconstrained and has one -- or more access discriminants. procedure Expand_Simple_Function_Return (N : Node_Id); -- Expand simple return from function. In the case where we are returning -- from a function body this is called by Expand_N_Simple_Return_Statement. ---------------------------------------------- -- Add_Access_Actual_To_Build_In_Place_Call -- ---------------------------------------------- procedure Add_Access_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Return_Object : Node_Id; Is_Access : Boolean := False) is Loc : constant Source_Ptr := Sloc (Function_Call); Obj_Address : Node_Id; Obj_Acc_Formal : Entity_Id; begin -- Locate the implicit access parameter in the called function Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access); -- If no return object is provided, then pass null if not Present (Return_Object) then Obj_Address := Make_Null (Loc); Set_Parent (Obj_Address, Function_Call); -- If Return_Object is already an expression of an access type, then use -- it directly, since it must be an access value denoting the return -- object, and couldn't possibly be the return object itself. elsif Is_Access then Obj_Address := Return_Object; Set_Parent (Obj_Address, Function_Call); -- Apply Unrestricted_Access to caller's return object else Obj_Address := Make_Attribute_Reference (Loc, Prefix => Return_Object, Attribute_Name => Name_Unrestricted_Access); Set_Parent (Return_Object, Obj_Address); Set_Parent (Obj_Address, Function_Call); end if; Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address); end Add_Access_Actual_To_Build_In_Place_Call; ------------------------------------------------------ -- Add_Unconstrained_Actuals_To_Build_In_Place_Call -- ------------------------------------------------------ procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Alloc_Form : BIP_Allocation_Form := Unspecified; Alloc_Form_Exp : Node_Id := Empty; Pool_Actual : Node_Id := Make_Null (No_Location)) is Loc : constant Source_Ptr := Sloc (Function_Call); Alloc_Form_Actual : Node_Id; Alloc_Form_Formal : Node_Id; Pool_Formal : Node_Id; begin -- The allocation form generally doesn't need to be passed in the case -- of a constrained result subtype, since normally the caller performs -- the allocation in that case. However this formal is still needed in -- the case where the function has a tagged result, because generally -- such functions can be called in a dispatching context and such calls -- must be handled like calls to class-wide functions. if Is_Constrained (Underlying_Type (Etype (Function_Id))) and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id))) then return; end if; -- Locate the implicit allocation form parameter in the called function. -- Maybe it would be better for each implicit formal of a build-in-place -- function to have a flag or a Uint attribute to identify it. ??? Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form); if Present (Alloc_Form_Exp) then pragma Assert (Alloc_Form = Unspecified); Alloc_Form_Actual := Alloc_Form_Exp; else pragma Assert (Alloc_Form /= Unspecified); Alloc_Form_Actual := Make_Integer_Literal (Loc, Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form))); end if; Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual); -- Pass the Storage_Pool parameter. This parameter is omitted on -- .NET/JVM/ZFP as those targets do not support pools. if VM_Target = No_VM and then RTE_Available (RE_Root_Storage_Pool_Ptr) then Pool_Formal := Build_In_Place_Formal (Function_Id, BIP_Storage_Pool); Analyze_And_Resolve (Pool_Actual, Etype (Pool_Formal)); Add_Extra_Actual_To_Call (Function_Call, Pool_Formal, Pool_Actual); end if; end Add_Unconstrained_Actuals_To_Build_In_Place_Call; ----------------------------------------------------------- -- Add_Finalization_Master_Actual_To_Build_In_Place_Call -- ----------------------------------------------------------- procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call : Node_Id; Func_Id : Entity_Id; Ptr_Typ : Entity_Id := Empty; Master_Exp : Node_Id := Empty) is begin if not Needs_BIP_Finalization_Master (Func_Id) then return; end if; declare Formal : constant Entity_Id := Build_In_Place_Formal (Func_Id, BIP_Finalization_Master); Loc : constant Source_Ptr := Sloc (Func_Call); Actual : Node_Id; Desig_Typ : Entity_Id; begin -- If there is a finalization master actual, such as the implicit -- finalization master of an enclosing build-in-place function, -- then this must be added as an extra actual of the call. if Present (Master_Exp) then Actual := Master_Exp; -- Case where the context does not require an actual master elsif No (Ptr_Typ) then Actual := Make_Null (Loc); else Desig_Typ := Directly_Designated_Type (Ptr_Typ); -- Check for a library-level access type whose designated type has -- supressed finalization. Such an access types lack a master. -- Pass a null actual to the callee in order to signal a missing -- master. if Is_Library_Level_Entity (Ptr_Typ) and then Finalize_Storage_Only (Desig_Typ) then Actual := Make_Null (Loc); -- Types in need of finalization actions elsif Needs_Finalization (Desig_Typ) then -- The general mechanism of creating finalization masters for -- anonymous access types is disabled by default, otherwise -- finalization masters will pop all over the place. Such types -- use context-specific masters. if Ekind (Ptr_Typ) = E_Anonymous_Access_Type and then No (Finalization_Master (Ptr_Typ)) then Build_Finalization_Master (Typ => Ptr_Typ, Ins_Node => Associated_Node_For_Itype (Ptr_Typ), Encl_Scope => Scope (Ptr_Typ)); end if; -- Access-to-controlled types should always have a master pragma Assert (Present (Finalization_Master (Ptr_Typ))); Actual := Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Finalization_Master (Ptr_Typ), Loc), Attribute_Name => Name_Unrestricted_Access); -- Tagged types else Actual := Make_Null (Loc); end if; end if; Analyze_And_Resolve (Actual, Etype (Formal)); -- Build the parameter association for the new actual and add it to -- the end of the function's actuals. Add_Extra_Actual_To_Call (Func_Call, Formal, Actual); end; end Add_Finalization_Master_Actual_To_Build_In_Place_Call; ------------------------------ -- Add_Extra_Actual_To_Call -- ------------------------------ procedure Add_Extra_Actual_To_Call (Subprogram_Call : Node_Id; Extra_Formal : Entity_Id; Extra_Actual : Node_Id) is Loc : constant Source_Ptr := Sloc (Subprogram_Call); Param_Assoc : Node_Id; begin Param_Assoc := Make_Parameter_Association (Loc, Selector_Name => New_Occurrence_Of (Extra_Formal, Loc), Explicit_Actual_Parameter => Extra_Actual); Set_Parent (Param_Assoc, Subprogram_Call); Set_Parent (Extra_Actual, Param_Assoc); if Present (Parameter_Associations (Subprogram_Call)) then if Nkind (Last (Parameter_Associations (Subprogram_Call))) = N_Parameter_Association then -- Find last named actual, and append declare L : Node_Id; begin L := First_Actual (Subprogram_Call); while Present (L) loop if No (Next_Actual (L)) then Set_Next_Named_Actual (Parent (L), Extra_Actual); exit; end if; Next_Actual (L); end loop; end; else Set_First_Named_Actual (Subprogram_Call, Extra_Actual); end if; Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call)); else Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc)); Set_First_Named_Actual (Subprogram_Call, Extra_Actual); end if; end Add_Extra_Actual_To_Call; --------------------------------------------- -- Add_Task_Actuals_To_Build_In_Place_Call -- --------------------------------------------- procedure Add_Task_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Master_Actual : Node_Id) is Loc : constant Source_Ptr := Sloc (Function_Call); Result_Subt : constant Entity_Id := Available_View (Etype (Function_Id)); Actual : Node_Id; Chain_Actual : Node_Id; Chain_Formal : Node_Id; Master_Formal : Node_Id; begin -- No such extra parameters are needed if there are no tasks if not Has_Task (Result_Subt) then return; end if; Actual := Master_Actual; -- Use a dummy _master actual in case of No_Task_Hierarchy if Restriction_Active (No_Task_Hierarchy) then Actual := New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc); -- In the case where we use the master associated with an access type, -- the actual is an entity and requires an explicit reference. elsif Nkind (Actual) = N_Defining_Identifier then Actual := New_Reference_To (Actual, Loc); end if; -- Locate the implicit master parameter in the called function Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Task_Master); Analyze_And_Resolve (Actual, Etype (Master_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Master_Formal, Actual); -- Locate the implicit activation chain parameter in the called function Chain_Formal := Build_In_Place_Formal (Function_Id, BIP_Activation_Chain); -- Create the actual which is a pointer to the current activation chain Chain_Actual := Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Name_uChain), Attribute_Name => Name_Unrestricted_Access); Analyze_And_Resolve (Chain_Actual, Etype (Chain_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Chain_Formal, Chain_Actual); end Add_Task_Actuals_To_Build_In_Place_Call; ----------------------- -- BIP_Formal_Suffix -- ----------------------- function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is begin case Kind is when BIP_Alloc_Form => return "BIPalloc"; when BIP_Storage_Pool => return "BIPstoragepool"; when BIP_Finalization_Master => return "BIPfinalizationmaster"; when BIP_Task_Master => return "BIPtaskmaster"; when BIP_Activation_Chain => return "BIPactivationchain"; when BIP_Object_Access => return "BIPaccess"; end case; end BIP_Formal_Suffix; --------------------------- -- Build_In_Place_Formal -- --------------------------- function Build_In_Place_Formal (Func : Entity_Id; Kind : BIP_Formal_Kind) return Entity_Id is Formal_Name : constant Name_Id := New_External_Name (Chars (Func), BIP_Formal_Suffix (Kind)); Extra_Formal : Entity_Id := Extra_Formals (Func); begin -- Maybe it would be better for each implicit formal of a build-in-place -- function to have a flag or a Uint attribute to identify it. ??? -- The return type in the function declaration may have been a limited -- view, and the extra formals for the function were not generated at -- that point. At the point of call the full view must be available and -- the extra formals can be created. if No (Extra_Formal) then Create_Extra_Formals (Func); Extra_Formal := Extra_Formals (Func); end if; loop pragma Assert (Present (Extra_Formal)); exit when Chars (Extra_Formal) = Formal_Name; Next_Formal_With_Extras (Extra_Formal); end loop; return Extra_Formal; end Build_In_Place_Formal; -------------------------------- -- Check_Overriding_Operation -- -------------------------------- procedure Check_Overriding_Operation (Subp : Entity_Id) is Typ : constant Entity_Id := Find_Dispatching_Type (Subp); Op_List : constant Elist_Id := Primitive_Operations (Typ); Op_Elmt : Elmt_Id; Prim_Op : Entity_Id; Par_Op : Entity_Id; begin if Is_Derived_Type (Typ) and then not Is_Private_Type (Typ) and then In_Open_Scopes (Scope (Etype (Typ))) and then Is_Base_Type (Typ) then -- Subp overrides an inherited private operation if there is an -- inherited operation with a different name than Subp (see -- Derive_Subprogram) whose Alias is a hidden subprogram with the -- same name as Subp. Op_Elmt := First_Elmt (Op_List); while Present (Op_Elmt) loop Prim_Op := Node (Op_Elmt); Par_Op := Alias (Prim_Op); if Present (Par_Op) and then not Comes_From_Source (Prim_Op) and then Chars (Prim_Op) /= Chars (Par_Op) and then Chars (Par_Op) = Chars (Subp) and then Is_Hidden (Par_Op) and then Type_Conformant (Prim_Op, Subp) then Set_DT_Position (Subp, DT_Position (Prim_Op)); end if; Next_Elmt (Op_Elmt); end loop; end if; end Check_Overriding_Operation; ------------------------------- -- Detect_Infinite_Recursion -- ------------------------------- procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); Var_List : constant Elist_Id := New_Elmt_List; -- List of globals referenced by body of procedure Call_List : constant Elist_Id := New_Elmt_List; -- List of recursive calls in body of procedure Shad_List : constant Elist_Id := New_Elmt_List; -- List of entity id's for entities created to capture the value of -- referenced globals on entry to the procedure. Scop : constant Uint := Scope_Depth (Spec); -- This is used to record the scope depth of the current procedure, so -- that we can identify global references. Max_Vars : constant := 4; -- Do not test more than four global variables Count_Vars : Natural := 0; -- Count variables found so far Var : Entity_Id; Elm : Elmt_Id; Ent : Entity_Id; Call : Elmt_Id; Decl : Node_Id; Test : Node_Id; Elm1 : Elmt_Id; Elm2 : Elmt_Id; Last : Node_Id; function Process (Nod : Node_Id) return Traverse_Result; -- Function to traverse the subprogram body (using Traverse_Func) ------------- -- Process -- ------------- function Process (Nod : Node_Id) return Traverse_Result is begin -- Procedure call if Nkind (Nod) = N_Procedure_Call_Statement then -- Case of one of the detected recursive calls if Is_Entity_Name (Name (Nod)) and then Has_Recursive_Call (Entity (Name (Nod))) and then Entity (Name (Nod)) = Spec then Append_Elmt (Nod, Call_List); return Skip; -- Any other procedure call may have side effects else return Abandon; end if; -- A call to a pure function can always be ignored elsif Nkind (Nod) = N_Function_Call and then Is_Entity_Name (Name (Nod)) and then Is_Pure (Entity (Name (Nod))) then return Skip; -- Case of an identifier reference elsif Nkind (Nod) = N_Identifier then Ent := Entity (Nod); -- If no entity, then ignore the reference -- Not clear why this can happen. To investigate, remove this -- test and look at the crash that occurs here in 3401-004 ??? if No (Ent) then return Skip; -- Ignore entities with no Scope, again not clear how this -- can happen, to investigate, look at 4108-008 ??? elsif No (Scope (Ent)) then return Skip; -- Ignore the reference if not to a more global object elsif Scope_Depth (Scope (Ent)) >= Scop then return Skip; -- References to types, exceptions and constants are always OK elsif Is_Type (Ent) or else Ekind (Ent) = E_Exception or else Ekind (Ent) = E_Constant then return Skip; -- If other than a non-volatile scalar variable, we have some -- kind of global reference (e.g. to a function) that we cannot -- deal with so we forget the attempt. elsif Ekind (Ent) /= E_Variable or else not Is_Scalar_Type (Etype (Ent)) or else Treat_As_Volatile (Ent) then return Abandon; -- Otherwise we have a reference to a global scalar else -- Loop through global entities already detected Elm := First_Elmt (Var_List); loop -- If not detected before, record this new global reference if No (Elm) then Count_Vars := Count_Vars + 1; if Count_Vars <= Max_Vars then Append_Elmt (Entity (Nod), Var_List); else return Abandon; end if; exit; -- If recorded before, ignore elsif Node (Elm) = Entity (Nod) then return Skip; -- Otherwise keep looking else Next_Elmt (Elm); end if; end loop; return Skip; end if; -- For all other node kinds, recursively visit syntactic children else return OK; end if; end Process; function Traverse_Body is new Traverse_Func (Process); -- Start of processing for Detect_Infinite_Recursion begin -- Do not attempt detection in No_Implicit_Conditional mode, since we -- won't be able to generate the code to handle the recursion in any -- case. if Restriction_Active (No_Implicit_Conditionals) then return; end if; -- Otherwise do traversal and quit if we get abandon signal if Traverse_Body (N) = Abandon then return; -- We must have a call, since Has_Recursive_Call was set. If not just -- ignore (this is only an error check, so if we have a funny situation, -- due to bugs or errors, we do not want to bomb!) elsif Is_Empty_Elmt_List (Call_List) then return; end if; -- Here is the case where we detect recursion at compile time -- Push our current scope for analyzing the declarations and code that -- we will insert for the checking. Push_Scope (Spec); -- This loop builds temporary variables for each of the referenced -- globals, so that at the end of the loop the list Shad_List contains -- these temporaries in one-to-one correspondence with the elements in -- Var_List. Last := Empty; Elm := First_Elmt (Var_List); while Present (Elm) loop Var := Node (Elm); Ent := Make_Temporary (Loc, 'S'); Append_Elmt (Ent, Shad_List); -- Insert a declaration for this temporary at the start of the -- declarations for the procedure. The temporaries are declared as -- constant objects initialized to the current values of the -- corresponding temporaries. Decl := Make_Object_Declaration (Loc, Defining_Identifier => Ent, Object_Definition => New_Occurrence_Of (Etype (Var), Loc), Constant_Present => True, Expression => New_Occurrence_Of (Var, Loc)); if No (Last) then Prepend (Decl, Declarations (N)); else Insert_After (Last, Decl); end if; Last := Decl; Analyze (Decl); Next_Elmt (Elm); end loop; -- Loop through calls Call := First_Elmt (Call_List); while Present (Call) loop -- Build a predicate expression of the form -- True -- and then global1 = temp1 -- and then global2 = temp2 -- ... -- This predicate determines if any of the global values -- referenced by the procedure have changed since the -- current call, if not an infinite recursion is assured. Test := New_Occurrence_Of (Standard_True, Loc); Elm1 := First_Elmt (Var_List); Elm2 := First_Elmt (Shad_List); while Present (Elm1) loop Test := Make_And_Then (Loc, Left_Opnd => Test, Right_Opnd => Make_Op_Eq (Loc, Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc), Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc))); Next_Elmt (Elm1); Next_Elmt (Elm2); end loop; -- Now we replace the call with the sequence -- if no-changes (see above) then -- raise Storage_Error; -- else -- original-call -- end if; Rewrite (Node (Call), Make_If_Statement (Loc, Condition => Test, Then_Statements => New_List ( Make_Raise_Storage_Error (Loc, Reason => SE_Infinite_Recursion)), Else_Statements => New_List ( Relocate_Node (Node (Call))))); Analyze (Node (Call)); Next_Elmt (Call); end loop; -- Remove temporary scope stack entry used for analysis Pop_Scope; end Detect_Infinite_Recursion; -------------------- -- Expand_Actuals -- -------------------- procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); Actual : Node_Id; Formal : Entity_Id; N_Node : Node_Id; Post_Call : List_Id; E_Formal : Entity_Id; procedure Add_Call_By_Copy_Code; -- For cases where the parameter must be passed by copy, this routine -- generates a temporary variable into which the actual is copied and -- then passes this as the parameter. For an OUT or IN OUT parameter, -- an assignment is also generated to copy the result back. The call -- also takes care of any constraint checks required for the type -- conversion case (on both the way in and the way out). procedure Add_Simple_Call_By_Copy_Code; -- This is similar to the above, but is used in cases where we know -- that all that is needed is to simply create a temporary and copy -- the value in and out of the temporary. procedure Check_Fortran_Logical; -- A value of type Logical that is passed through a formal parameter -- must be normalized because .TRUE. usually does not have the same -- representation as True. We assume that .FALSE. = False = 0. -- What about functions that return a logical type ??? function Is_Legal_Copy return Boolean; -- Check that an actual can be copied before generating the temporary -- to be used in the call. If the actual is of a by_reference type then -- the program is illegal (this can only happen in the presence of -- rep. clauses that force an incorrect alignment). If the formal is -- a by_reference parameter imposed by a DEC pragma, emit a warning to -- the effect that this might lead to unaligned arguments. function Make_Var (Actual : Node_Id) return Entity_Id; -- Returns an entity that refers to the given actual parameter, -- Actual (not including any type conversion). If Actual is an -- entity name, then this entity is returned unchanged, otherwise -- a renaming is created to provide an entity for the actual. procedure Reset_Packed_Prefix; -- The expansion of a packed array component reference is delayed in -- the context of a call. Now we need to complete the expansion, so we -- unmark the analyzed bits in all prefixes. --------------------------- -- Add_Call_By_Copy_Code -- --------------------------- procedure Add_Call_By_Copy_Code is Expr : Node_Id; Init : Node_Id; Temp : Entity_Id; Indic : Node_Id; Var : Entity_Id; F_Typ : constant Entity_Id := Etype (Formal); V_Typ : Entity_Id; Crep : Boolean; begin if not Is_Legal_Copy then return; end if; Temp := Make_Temporary (Loc, 'T', Actual); -- Use formal type for temp, unless formal type is an unconstrained -- array, in which case we don't have to worry about bounds checks, -- and we use the actual type, since that has appropriate bounds. if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then Indic := New_Occurrence_Of (Etype (Actual), Loc); else Indic := New_Occurrence_Of (Etype (Formal), Loc); end if; if Nkind (Actual) = N_Type_Conversion then V_Typ := Etype (Expression (Actual)); -- If the formal is an (in-)out parameter, capture the name -- of the variable in order to build the post-call assignment. Var := Make_Var (Expression (Actual)); Crep := not Same_Representation (F_Typ, Etype (Expression (Actual))); else V_Typ := Etype (Actual); Var := Make_Var (Actual); Crep := False; end if; -- Setup initialization for case of in out parameter, or an out -- parameter where the formal is an unconstrained array (in the -- latter case, we have to pass in an object with bounds). -- If this is an out parameter, the initial copy is wasteful, so as -- an optimization for the one-dimensional case we extract the -- bounds of the actual and build an uninitialized temporary of the -- right size. if Ekind (Formal) = E_In_Out_Parameter or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ)) then if Nkind (Actual) = N_Type_Conversion then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; elsif Ekind (Formal) = E_Out_Parameter and then Is_Array_Type (F_Typ) and then Number_Dimensions (F_Typ) = 1 and then not Has_Non_Null_Base_Init_Proc (F_Typ) then -- Actual is a one-dimensional array or slice, and the type -- requires no initialization. Create a temporary of the -- right size, but do not copy actual into it (optimization). Init := Empty; Indic := Make_Subtype_Indication (Loc, Subtype_Mark => New_Occurrence_Of (F_Typ, Loc), Constraint => Make_Index_Or_Discriminant_Constraint (Loc, Constraints => New_List ( Make_Range (Loc, Low_Bound => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Var, Loc), Attribute_Name => Name_First), High_Bound => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Var, Loc), Attribute_Name => Name_Last))))); else Init := New_Occurrence_Of (Var, Loc); end if; -- An initialization is created for packed conversions as -- actuals for out parameters to enable Make_Object_Declaration -- to determine the proper subtype for N_Node. Note that this -- is wasteful because the extra copying on the call side is -- not required for such out parameters. ??? elsif Ekind (Formal) = E_Out_Parameter and then Nkind (Actual) = N_Type_Conversion and then (Is_Bit_Packed_Array (F_Typ) or else Is_Bit_Packed_Array (Etype (Expression (Actual)))) then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; elsif Ekind (Formal) = E_In_Parameter then -- Handle the case in which the actual is a type conversion if Nkind (Actual) = N_Type_Conversion then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; else Init := New_Occurrence_Of (Var, Loc); end if; else Init := Empty; end if; N_Node := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => Indic, Expression => Init); Set_Assignment_OK (N_Node); Insert_Action (N, N_Node); -- Now, normally the deal here is that we use the defining -- identifier created by that object declaration. There is -- one exception to this. In the change of representation case -- the above declaration will end up looking like: -- temp : type := identifier; -- And in this case we might as well use the identifier directly -- and eliminate the temporary. Note that the analysis of the -- declaration was not a waste of time in that case, since it is -- what generated the necessary change of representation code. If -- the change of representation introduced additional code, as in -- a fixed-integer conversion, the expression is not an identifier -- and must be kept. if Crep and then Present (Expression (N_Node)) and then Is_Entity_Name (Expression (N_Node)) then Temp := Entity (Expression (N_Node)); Rewrite (N_Node, Make_Null_Statement (Loc)); end if; -- For IN parameter, all we do is to replace the actual if Ekind (Formal) = E_In_Parameter then Rewrite (Actual, New_Reference_To (Temp, Loc)); Analyze (Actual); -- Processing for OUT or IN OUT parameter else -- Kill current value indications for the temporary variable we -- created, since we just passed it as an OUT parameter. Kill_Current_Values (Temp); Set_Is_Known_Valid (Temp, False); -- If type conversion, use reverse conversion on exit if Nkind (Actual) = N_Type_Conversion then if Conversion_OK (Actual) then Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); else Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); end if; else Expr := New_Occurrence_Of (Temp, Loc); end if; Rewrite (Actual, New_Reference_To (Temp, Loc)); Analyze (Actual); -- If the actual is a conversion of a packed reference, it may -- already have been expanded by Remove_Side_Effects, and the -- resulting variable is a temporary which does not designate -- the proper out-parameter, which may not be addressable. In -- that case, generate an assignment to the original expression -- (before expansion of the packed reference) so that the proper -- expansion of assignment to a packed component can take place. declare Obj : Node_Id; Lhs : Node_Id; begin if Is_Renaming_Of_Object (Var) and then Nkind (Renamed_Object (Var)) = N_Selected_Component and then Is_Entity_Name (Prefix (Renamed_Object (Var))) and then Nkind (Original_Node (Prefix (Renamed_Object (Var)))) = N_Indexed_Component and then Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var)))) then Obj := Renamed_Object (Var); Lhs := Make_Selected_Component (Loc, Prefix => New_Copy_Tree (Original_Node (Prefix (Obj))), Selector_Name => New_Copy (Selector_Name (Obj))); Reset_Analyzed_Flags (Lhs); else Lhs := New_Occurrence_Of (Var, Loc); end if; Set_Assignment_OK (Lhs); if Is_Access_Type (E_Formal) and then Is_Entity_Name (Lhs) and then Present (Effective_Extra_Accessibility (Entity (Lhs))) then -- Copyback target is an Ada 2012 stand-alone object -- of an anonymous access type pragma Assert (Ada_Version >= Ada_2012); if Type_Access_Level (E_Formal) > Object_Access_Level (Lhs) then Append_To (Post_Call, Make_Raise_Program_Error (Loc, Reason => PE_Accessibility_Check_Failed)); end if; Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => Lhs, Expression => Expr)); -- We would like to somehow suppress generation of the -- extra_accessibility assignment generated by the expansion -- of the above assignment statement. It's not a correctness -- issue because the following assignment renders it dead, -- but generating back-to-back assignments to the same -- target is undesirable. ??? Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of ( Effective_Extra_Accessibility (Entity (Lhs)), Loc), Expression => Make_Integer_Literal (Loc, Type_Access_Level (E_Formal)))); else Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => Lhs, Expression => Expr)); end if; end; end if; end Add_Call_By_Copy_Code; ---------------------------------- -- Add_Simple_Call_By_Copy_Code -- ---------------------------------- procedure Add_Simple_Call_By_Copy_Code is Temp : Entity_Id; Decl : Node_Id; Incod : Node_Id; Outcod : Node_Id; Lhs : Node_Id; Rhs : Node_Id; Indic : Node_Id; F_Typ : constant Entity_Id := Etype (Formal); begin if not Is_Legal_Copy then return; end if; -- Use formal type for temp, unless formal type is an unconstrained -- array, in which case we don't have to worry about bounds checks, -- and we use the actual type, since that has appropriate bounds. if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then Indic := New_Occurrence_Of (Etype (Actual), Loc); else Indic := New_Occurrence_Of (Etype (Formal), Loc); end if; -- Prepare to generate code Reset_Packed_Prefix; Temp := Make_Temporary (Loc, 'T', Actual); Incod := Relocate_Node (Actual); Outcod := New_Copy_Tree (Incod); -- Generate declaration of temporary variable, initializing it -- with the input parameter unless we have an OUT formal or -- this is an initialization call. -- If the formal is an out parameter with discriminants, the -- discriminants must be captured even if the rest of the object -- is in principle uninitialized, because the discriminants may -- be read by the called subprogram. if Ekind (Formal) = E_Out_Parameter then Incod := Empty; if Has_Discriminants (Etype (Formal)) then Indic := New_Occurrence_Of (Etype (Actual), Loc); end if; elsif Inside_Init_Proc then -- Could use a comment here to match comment below ??? if Nkind (Actual) /= N_Selected_Component or else not Has_Discriminant_Dependent_Constraint (Entity (Selector_Name (Actual))) then Incod := Empty; -- Otherwise, keep the component in order to generate the proper -- actual subtype, that depends on enclosing discriminants. else null; end if; end if; Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => Indic, Expression => Incod); if Inside_Init_Proc and then No (Incod) then -- If the call is to initialize a component of a composite type, -- and the component does not depend on discriminants, use the -- actual type of the component. This is required in case the -- component is constrained, because in general the formal of the -- initialization procedure will be unconstrained. Note that if -- the component being initialized is constrained by an enclosing -- discriminant, the presence of the initialization in the -- declaration will generate an expression for the actual subtype. Set_No_Initialization (Decl); Set_Object_Definition (Decl, New_Occurrence_Of (Etype (Actual), Loc)); end if; Insert_Action (N, Decl); -- The actual is simply a reference to the temporary Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); -- Generate copy out if OUT or IN OUT parameter if Ekind (Formal) /= E_In_Parameter then Lhs := Outcod; Rhs := New_Occurrence_Of (Temp, Loc); -- Deal with conversion if Nkind (Lhs) = N_Type_Conversion then Lhs := Expression (Lhs); Rhs := Convert_To (Etype (Actual), Rhs); end if; Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => Lhs, Expression => Rhs)); Set_Assignment_OK (Name (Last (Post_Call))); end if; end Add_Simple_Call_By_Copy_Code; --------------------------- -- Check_Fortran_Logical -- --------------------------- procedure Check_Fortran_Logical is Logical : constant Entity_Id := Etype (Formal); Var : Entity_Id; -- Note: this is very incomplete, e.g. it does not handle arrays -- of logical values. This is really not the right approach at all???) begin if Convention (Subp) = Convention_Fortran and then Root_Type (Etype (Formal)) = Standard_Boolean and then Ekind (Formal) /= E_In_Parameter then Var := Make_Var (Actual); Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Var, Loc), Expression => Unchecked_Convert_To ( Logical, Make_Op_Ne (Loc, Left_Opnd => New_Occurrence_Of (Var, Loc), Right_Opnd => Unchecked_Convert_To ( Logical, New_Occurrence_Of (Standard_False, Loc)))))); end if; end Check_Fortran_Logical; ------------------- -- Is_Legal_Copy -- ------------------- function Is_Legal_Copy return Boolean is begin -- An attempt to copy a value of such a type can only occur if -- representation clauses give the actual a misaligned address. if Is_By_Reference_Type (Etype (Formal)) then -- If the front-end does not perform full type layout, the actual -- may in fact be properly aligned but there is not enough front- -- end information to determine this. In that case gigi will emit -- an error if a copy is not legal, or generate the proper code. -- For other backends we report the error now. -- Seems wrong to be issuing an error in the expander, since it -- will be missed in -gnatc mode ??? if Frontend_Layout_On_Target then Error_Msg_N ("misaligned actual cannot be passed by reference", Actual); end if; return False; -- For users of Starlet, we assume that the specification of by- -- reference mechanism is mandatory. This may lead to unaligned -- objects but at least for DEC legacy code it is known to work. -- The warning will alert users of this code that a problem may -- be lurking. elsif Mechanism (Formal) = By_Reference and then Is_Valued_Procedure (Scope (Formal)) then Error_Msg_N ("by_reference actual may be misaligned?", Actual); return False; else return True; end if; end Is_Legal_Copy; -------------- -- Make_Var -- -------------- function Make_Var (Actual : Node_Id) return Entity_Id is Var : Entity_Id; begin if Is_Entity_Name (Actual) then return Entity (Actual); else Var := Make_Temporary (Loc, 'T', Actual); N_Node := Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Var, Subtype_Mark => New_Occurrence_Of (Etype (Actual), Loc), Name => Relocate_Node (Actual)); Insert_Action (N, N_Node); return Var; end if; end Make_Var; ------------------------- -- Reset_Packed_Prefix -- ------------------------- procedure Reset_Packed_Prefix is Pfx : Node_Id := Actual; begin loop Set_Analyzed (Pfx, False); exit when not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component); Pfx := Prefix (Pfx); end loop; end Reset_Packed_Prefix; -- Start of processing for Expand_Actuals begin Post_Call := New_List; Formal := First_Formal (Subp); Actual := First_Actual (N); while Present (Formal) loop E_Formal := Etype (Formal); if Is_Scalar_Type (E_Formal) or else Nkind (Actual) = N_Slice then Check_Fortran_Logical; -- RM 6.4.1 (11) elsif Ekind (Formal) /= E_Out_Parameter then -- The unusual case of the current instance of a protected type -- requires special handling. This can only occur in the context -- of a call within the body of a protected operation. if Is_Entity_Name (Actual) and then Ekind (Entity (Actual)) = E_Protected_Type and then In_Open_Scopes (Entity (Actual)) then if Scope (Subp) /= Entity (Actual) then Error_Msg_N ("operation outside protected type may not " & "call back its protected operations?", Actual); end if; Rewrite (Actual, Expand_Protected_Object_Reference (N, Entity (Actual))); end if; -- Ada 2005 (AI-318-02): If the actual parameter is a call to a -- build-in-place function, then a temporary return object needs -- to be created and access to it must be passed to the function. -- Currently we limit such functions to those with inherently -- limited result subtypes, but eventually we plan to expand the -- functions that are treated as build-in-place to include other -- composite result types. if Is_Build_In_Place_Function_Call (Actual) then Make_Build_In_Place_Call_In_Anonymous_Context (Actual); end if; Apply_Constraint_Check (Actual, E_Formal); -- Out parameter case. No constraint checks on access type -- RM 6.4.1 (13) elsif Is_Access_Type (E_Formal) then null; -- RM 6.4.1 (14) elsif Has_Discriminants (Base_Type (E_Formal)) or else Has_Non_Null_Base_Init_Proc (E_Formal) then Apply_Constraint_Check (Actual, E_Formal); -- RM 6.4.1 (15) else Apply_Constraint_Check (Actual, Base_Type (E_Formal)); end if; -- Processing for IN-OUT and OUT parameters if Ekind (Formal) /= E_In_Parameter then -- For type conversions of arrays, apply length/range checks if Is_Array_Type (E_Formal) and then Nkind (Actual) = N_Type_Conversion then if Is_Constrained (E_Formal) then Apply_Length_Check (Expression (Actual), E_Formal); else Apply_Range_Check (Expression (Actual), E_Formal); end if; end if; -- If argument is a type conversion for a type that is passed -- by copy, then we must pass the parameter by copy. if Nkind (Actual) = N_Type_Conversion and then (Is_Numeric_Type (E_Formal) or else Is_Access_Type (E_Formal) or else Is_Enumeration_Type (E_Formal) or else Is_Bit_Packed_Array (Etype (Formal)) or else Is_Bit_Packed_Array (Etype (Expression (Actual))) -- Also pass by copy if change of representation or else not Same_Representation (Etype (Formal), Etype (Expression (Actual)))) then Add_Call_By_Copy_Code; -- References to components of bit packed arrays are expanded -- at this point, rather than at the point of analysis of the -- actuals, to handle the expansion of the assignment to -- [in] out parameters. elsif Is_Ref_To_Bit_Packed_Array (Actual) then Add_Simple_Call_By_Copy_Code; -- If a non-scalar actual is possibly bit-aligned, we need a copy -- because the back-end cannot cope with such objects. In other -- cases where alignment forces a copy, the back-end generates -- it properly. It should not be generated unconditionally in the -- front-end because it does not know precisely the alignment -- requirements of the target, and makes too conservative an -- estimate, leading to superfluous copies or spurious errors -- on by-reference parameters. elsif Nkind (Actual) = N_Selected_Component and then Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual))) and then not Represented_As_Scalar (Etype (Formal)) then Add_Simple_Call_By_Copy_Code; -- References to slices of bit packed arrays are expanded elsif Is_Ref_To_Bit_Packed_Slice (Actual) then Add_Call_By_Copy_Code; -- References to possibly unaligned slices of arrays are expanded elsif Is_Possibly_Unaligned_Slice (Actual) then Add_Call_By_Copy_Code; -- Deal with access types where the actual subtype and the -- formal subtype are not the same, requiring a check. -- It is necessary to exclude tagged types because of "downward -- conversion" errors. elsif Is_Access_Type (E_Formal) and then not Same_Type (E_Formal, Etype (Actual)) and then not Is_Tagged_Type (Designated_Type (E_Formal)) then Add_Call_By_Copy_Code; -- If the actual is not a scalar and is marked for volatile -- treatment, whereas the formal is not volatile, then pass -- by copy unless it is a by-reference type. -- Note: we use Is_Volatile here rather than Treat_As_Volatile, -- because this is the enforcement of a language rule that applies -- only to "real" volatile variables, not e.g. to the address -- clause overlay case. elsif Is_Entity_Name (Actual) and then Is_Volatile (Entity (Actual)) and then not Is_By_Reference_Type (Etype (Actual)) and then not Is_Scalar_Type (Etype (Entity (Actual))) and then not Is_Volatile (E_Formal) then Add_Call_By_Copy_Code; elsif Nkind (Actual) = N_Indexed_Component and then Is_Entity_Name (Prefix (Actual)) and then Has_Volatile_Components (Entity (Prefix (Actual))) then Add_Call_By_Copy_Code; -- Add call-by-copy code for the case of scalar out parameters -- when it is not known at compile time that the subtype of the -- formal is a subrange of the subtype of the actual (or vice -- versa for in out parameters), in order to get range checks -- on such actuals. (Maybe this case should be handled earlier -- in the if statement???) elsif Is_Scalar_Type (E_Formal) and then (not In_Subrange_Of (E_Formal, Etype (Actual)) or else (Ekind (Formal) = E_In_Out_Parameter and then not In_Subrange_Of (Etype (Actual), E_Formal))) then -- Perhaps the setting back to False should be done within -- Add_Call_By_Copy_Code, since it could get set on other -- cases occurring above??? if Do_Range_Check (Actual) then Set_Do_Range_Check (Actual, False); end if; Add_Call_By_Copy_Code; end if; -- Processing for IN parameters else -- For IN parameters is in the packed array case, we expand an -- indexed component (the circuit in Exp_Ch4 deliberately left -- indexed components appearing as actuals untouched, so that -- the special processing above for the OUT and IN OUT cases -- could be performed. We could make the test in Exp_Ch4 more -- complex and have it detect the parameter mode, but it is -- easier simply to handle all cases here.) if Nkind (Actual) = N_Indexed_Component and then Is_Packed (Etype (Prefix (Actual))) then Reset_Packed_Prefix; Expand_Packed_Element_Reference (Actual); -- If we have a reference to a bit packed array, we copy it, since -- the actual must be byte aligned. -- Is this really necessary in all cases??? elsif Is_Ref_To_Bit_Packed_Array (Actual) then Add_Simple_Call_By_Copy_Code; -- If a non-scalar actual is possibly unaligned, we need a copy elsif Is_Possibly_Unaligned_Object (Actual) and then not Represented_As_Scalar (Etype (Formal)) then Add_Simple_Call_By_Copy_Code; -- Similarly, we have to expand slices of packed arrays here -- because the result must be byte aligned. elsif Is_Ref_To_Bit_Packed_Slice (Actual) then Add_Call_By_Copy_Code; -- Only processing remaining is to pass by copy if this is a -- reference to a possibly unaligned slice, since the caller -- expects an appropriately aligned argument. elsif Is_Possibly_Unaligned_Slice (Actual) then Add_Call_By_Copy_Code; -- An unusual case: a current instance of an enclosing task can be -- an actual, and must be replaced by a reference to self. elsif Is_Entity_Name (Actual) and then Is_Task_Type (Entity (Actual)) then if In_Open_Scopes (Entity (Actual)) then Rewrite (Actual, (Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Self), Loc)))); Analyze (Actual); -- A task type cannot otherwise appear as an actual else raise Program_Error; end if; end if; end if; Next_Formal (Formal); Next_Actual (Actual); end loop; -- Find right place to put post call stuff if it is present if not Is_Empty_List (Post_Call) then -- Cases where the call is not a member of a statement list if not Is_List_Member (N) then declare P : Node_Id := Parent (N); begin -- In Ada 2012 the call may be a function call in an expression -- (since OUT and IN OUT parameters are now allowed for such -- calls. The write-back of (in)-out parameters is handled -- by the back-end, but the constraint checks generated when -- subtypes of formal and actual don't match must be inserted -- in the form of assignments, at the nearest point after the -- declaration or statement that contains the call. if Ada_Version >= Ada_2012 and then Nkind (N) = N_Function_Call then while Nkind (P) not in N_Declaration and then Nkind (P) not in N_Statement_Other_Than_Procedure_Call loop P := Parent (P); end loop; Insert_Actions_After (P, Post_Call); -- If not the special Ada 2012 case of a function call, then -- we must have the triggering statement of a triggering -- alternative or an entry call alternative, and we can add -- the post call stuff to the corresponding statement list. else pragma Assert (Nkind_In (P, N_Triggering_Alternative, N_Entry_Call_Alternative)); if Is_Non_Empty_List (Statements (P)) then Insert_List_Before_And_Analyze (First (Statements (P)), Post_Call); else Set_Statements (P, Post_Call); end if; end if; end; -- Otherwise, normal case where N is in a statement sequence, -- just put the post-call stuff after the call statement. else Insert_Actions_After (N, Post_Call); end if; end if; -- The call node itself is re-analyzed in Expand_Call end Expand_Actuals; ----------------- -- Expand_Call -- ----------------- -- This procedure handles expansion of function calls and procedure call -- statements (i.e. it serves as the body for Expand_N_Function_Call and -- Expand_N_Procedure_Call_Statement). Processing for calls includes: -- Replace call to Raise_Exception by Raise_Exception_Always if possible -- Provide values of actuals for all formals in Extra_Formals list -- Replace "call" to enumeration literal function by literal itself -- Rewrite call to predefined operator as operator -- Replace actuals to in-out parameters that are numeric conversions, -- with explicit assignment to temporaries before and after the call. -- Remove optional actuals if First_Optional_Parameter specified. -- Note that the list of actuals has been filled with default expressions -- during semantic analysis of the call. Only the extra actuals required -- for the 'Constrained attribute and for accessibility checks are added -- at this point. procedure Expand_Call (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Call_Node : Node_Id := N; Extra_Actuals : List_Id := No_List; Prev : Node_Id := Empty; procedure Add_Actual_Parameter (Insert_Param : Node_Id); -- Adds one entry to the end of the actual parameter list. Used for -- default parameters and for extra actuals (for Extra_Formals). The -- argument is an N_Parameter_Association node. procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id); -- Adds an extra actual to the list of extra actuals. Expr is the -- expression for the value of the actual, EF is the entity for the -- extra formal. function Inherited_From_Formal (S : Entity_Id) return Entity_Id; -- Within an instance, a type derived from a non-tagged formal derived -- type inherits from the original parent, not from the actual. The -- current derivation mechanism has the derived type inherit from the -- actual, which is only correct outside of the instance. If the -- subprogram is inherited, we test for this particular case through a -- convoluted tree traversal before setting the proper subprogram to be -- called. function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean; -- Determine if Subp denotes a non-dispatching call to a Deep routine function New_Value (From : Node_Id) return Node_Id; -- From is the original Expression. New_Value is equivalent to a call -- to Duplicate_Subexpr with an explicit dereference when From is an -- access parameter. -------------------------- -- Add_Actual_Parameter -- -------------------------- procedure Add_Actual_Parameter (Insert_Param : Node_Id) is Actual_Expr : constant Node_Id := Explicit_Actual_Parameter (Insert_Param); begin -- Case of insertion is first named actual if No (Prev) or else Nkind (Parent (Prev)) /= N_Parameter_Association then Set_Next_Named_Actual (Insert_Param, First_Named_Actual (Call_Node)); Set_First_Named_Actual (Call_Node, Actual_Expr); if No (Prev) then if No (Parameter_Associations (Call_Node)) then Set_Parameter_Associations (Call_Node, New_List); end if; Append (Insert_Param, Parameter_Associations (Call_Node)); else Insert_After (Prev, Insert_Param); end if; -- Case of insertion is not first named actual else Set_Next_Named_Actual (Insert_Param, Next_Named_Actual (Parent (Prev))); Set_Next_Named_Actual (Parent (Prev), Actual_Expr); Append (Insert_Param, Parameter_Associations (Call_Node)); end if; Prev := Actual_Expr; end Add_Actual_Parameter; ---------------------- -- Add_Extra_Actual -- ---------------------- procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is Loc : constant Source_Ptr := Sloc (Expr); begin if Extra_Actuals = No_List then Extra_Actuals := New_List; Set_Parent (Extra_Actuals, Call_Node); end if; Append_To (Extra_Actuals, Make_Parameter_Association (Loc, Selector_Name => Make_Identifier (Loc, Chars (EF)), Explicit_Actual_Parameter => Expr)); Analyze_And_Resolve (Expr, Etype (EF)); if Nkind (Call_Node) = N_Function_Call then Set_Is_Accessibility_Actual (Parent (Expr)); end if; end Add_Extra_Actual; --------------------------- -- Inherited_From_Formal -- --------------------------- function Inherited_From_Formal (S : Entity_Id) return Entity_Id is Par : Entity_Id; Gen_Par : Entity_Id; Gen_Prim : Elist_Id; Elmt : Elmt_Id; Indic : Node_Id; begin -- If the operation is inherited, it is attached to the corresponding -- type derivation. If the parent in the derivation is a generic -- actual, it is a subtype of the actual, and we have to recover the -- original derived type declaration to find the proper parent. if Nkind (Parent (S)) /= N_Full_Type_Declaration or else not Is_Derived_Type (Defining_Identifier (Parent (S))) or else Nkind (Type_Definition (Original_Node (Parent (S)))) /= N_Derived_Type_Definition or else not In_Instance then return Empty; else Indic := Subtype_Indication (Type_Definition (Original_Node (Parent (S)))); if Nkind (Indic) = N_Subtype_Indication then Par := Entity (Subtype_Mark (Indic)); else Par := Entity (Indic); end if; end if; if not Is_Generic_Actual_Type (Par) or else Is_Tagged_Type (Par) or else Nkind (Parent (Par)) /= N_Subtype_Declaration or else not In_Open_Scopes (Scope (Par)) then return Empty; else Gen_Par := Generic_Parent_Type (Parent (Par)); end if; -- If the actual has no generic parent type, the formal is not -- a formal derived type, so nothing to inherit. if No (Gen_Par) then return Empty; end if; -- If the generic parent type is still the generic type, this is a -- private formal, not a derived formal, and there are no operations -- inherited from the formal. if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then return Empty; end if; Gen_Prim := Collect_Primitive_Operations (Gen_Par); Elmt := First_Elmt (Gen_Prim); while Present (Elmt) loop if Chars (Node (Elmt)) = Chars (S) then declare F1 : Entity_Id; F2 : Entity_Id; begin F1 := First_Formal (S); F2 := First_Formal (Node (Elmt)); while Present (F1) and then Present (F2) loop if Etype (F1) = Etype (F2) or else Etype (F2) = Gen_Par then Next_Formal (F1); Next_Formal (F2); else Next_Elmt (Elmt); exit; -- not the right subprogram end if; return Node (Elmt); end loop; end; else Next_Elmt (Elmt); end if; end loop; raise Program_Error; end Inherited_From_Formal; ------------------------- -- Is_Direct_Deep_Call -- ------------------------- function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean is begin if Is_TSS (Subp, TSS_Deep_Adjust) or else Is_TSS (Subp, TSS_Deep_Finalize) or else Is_TSS (Subp, TSS_Deep_Initialize) then declare Actual : Node_Id; Formal : Node_Id; begin Actual := First (Parameter_Associations (N)); Formal := First_Formal (Subp); while Present (Actual) and then Present (Formal) loop if Nkind (Actual) = N_Identifier and then Is_Controlling_Actual (Actual) and then Etype (Actual) = Etype (Formal) then return True; end if; Next (Actual); Next_Formal (Formal); end loop; end; end if; return False; end Is_Direct_Deep_Call; --------------- -- New_Value -- --------------- function New_Value (From : Node_Id) return Node_Id is Res : constant Node_Id := Duplicate_Subexpr (From); begin if Is_Access_Type (Etype (From)) then return Make_Explicit_Dereference (Sloc (From), Prefix => Res); else return Res; end if; end New_Value; -- Local variables Curr_S : constant Entity_Id := Current_Scope; Remote : constant Boolean := Is_Remote_Call (Call_Node); Actual : Node_Id; Formal : Entity_Id; Orig_Subp : Entity_Id := Empty; Param_Count : Natural := 0; Parent_Formal : Entity_Id; Parent_Subp : Entity_Id; Scop : Entity_Id; Subp : Entity_Id; Prev_Orig : Node_Id; -- Original node for an actual, which may have been rewritten. If the -- actual is a function call that has been transformed from a selected -- component, the original node is unanalyzed. Otherwise, it carries -- semantic information used to generate additional actuals. CW_Interface_Formals_Present : Boolean := False; -- Start of processing for Expand_Call begin -- Expand the procedure call if the first actual has a dimension and if -- the procedure is Put (Ada 2012). if Ada_Version >= Ada_2012 and then Nkind (Call_Node) = N_Procedure_Call_Statement and then Present (Parameter_Associations (Call_Node)) then Expand_Put_Call_With_Dimension_Symbol (Call_Node); end if; -- Remove the dimensions of every parameters in call Remove_Dimension_In_Call (N); -- Ignore if previous error if Nkind (Call_Node) in N_Has_Etype and then Etype (Call_Node) = Any_Type then return; end if; -- Call using access to subprogram with explicit dereference if Nkind (Name (Call_Node)) = N_Explicit_Dereference then Subp := Etype (Name (Call_Node)); Parent_Subp := Empty; -- Case of call to simple entry, where the Name is a selected component -- whose prefix is the task, and whose selector name is the entry name elsif Nkind (Name (Call_Node)) = N_Selected_Component then Subp := Entity (Selector_Name (Name (Call_Node))); Parent_Subp := Empty; -- Case of call to member of entry family, where Name is an indexed -- component, with the prefix being a selected component giving the -- task and entry family name, and the index being the entry index. elsif Nkind (Name (Call_Node)) = N_Indexed_Component then Subp := Entity (Selector_Name (Prefix (Name (Call_Node)))); Parent_Subp := Empty; -- Normal case else Subp := Entity (Name (Call_Node)); Parent_Subp := Alias (Subp); -- Replace call to Raise_Exception by call to Raise_Exception_Always -- if we can tell that the first parameter cannot possibly be null. -- This improves efficiency by avoiding a run-time test. -- We do not do this if Raise_Exception_Always does not exist, which -- can happen in configurable run time profiles which provide only a -- Raise_Exception. if Is_RTE (Subp, RE_Raise_Exception) and then RTE_Available (RE_Raise_Exception_Always) then declare FA : constant Node_Id := Original_Node (First_Actual (Call_Node)); begin -- The case we catch is where the first argument is obtained -- using the Identity attribute (which must always be -- non-null). if Nkind (FA) = N_Attribute_Reference and then Attribute_Name (FA) = Name_Identity then Subp := RTE (RE_Raise_Exception_Always); Set_Name (Call_Node, New_Occurrence_Of (Subp, Loc)); end if; end; end if; if Ekind (Subp) = E_Entry then Parent_Subp := Empty; end if; end if; -- Detect the following code in System.Finalization_Masters only on -- .NET/JVM targets: -- -- procedure Finalize (Master : in out Finalization_Master) is -- begin -- . . . -- begin -- Finalize (Curr_Ptr.all); -- -- Since .NET/JVM compilers lack address arithmetic and Deep_Finalize -- cannot be named in library or user code, the compiler has to install -- a kludge and transform the call to Finalize into Deep_Finalize. if VM_Target /= No_VM and then Chars (Subp) = Name_Finalize and then Ekind (Curr_S) = E_Block and then Ekind (Scope (Curr_S)) = E_Procedure and then Chars (Scope (Curr_S)) = Name_Finalize and then Etype (First_Formal (Scope (Curr_S))) = RTE (RE_Finalization_Master) then declare Deep_Fin : constant Entity_Id := Find_Prim_Op (RTE (RE_Root_Controlled), TSS_Deep_Finalize); begin -- Since Root_Controlled is a tagged type, the compiler should -- always generate Deep_Finalize for it. pragma Assert (Present (Deep_Fin)); -- Generate: -- Deep_Finalize (Curr_Ptr.all); Rewrite (N, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (Deep_Fin, Loc), Parameter_Associations => New_Copy_List_Tree (Parameter_Associations (N)))); Analyze (N); return; end; end if; -- Ada 2005 (AI-345): We have a procedure call as a triggering -- alternative in an asynchronous select or as an entry call in -- a conditional or timed select. Check whether the procedure call -- is a renaming of an entry and rewrite it as an entry call. if Ada_Version >= Ada_2005 and then Nkind (Call_Node) = N_Procedure_Call_Statement and then ((Nkind (Parent (Call_Node)) = N_Triggering_Alternative and then Triggering_Statement (Parent (Call_Node)) = Call_Node) or else (Nkind (Parent (Call_Node)) = N_Entry_Call_Alternative and then Entry_Call_Statement (Parent (Call_Node)) = Call_Node)) then declare Ren_Decl : Node_Id; Ren_Root : Entity_Id := Subp; begin -- This may be a chain of renamings, find the root if Present (Alias (Ren_Root)) then Ren_Root := Alias (Ren_Root); end if; if Present (Original_Node (Parent (Parent (Ren_Root)))) then Ren_Decl := Original_Node (Parent (Parent (Ren_Root))); if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then Rewrite (Call_Node, Make_Entry_Call_Statement (Loc, Name => New_Copy_Tree (Name (Ren_Decl)), Parameter_Associations => New_Copy_List_Tree (Parameter_Associations (Call_Node)))); return; end if; end if; end; end if; -- First step, compute extra actuals, corresponding to any Extra_Formals -- present. Note that we do not access Extra_Formals directly, instead -- we simply note the presence of the extra formals as we process the -- regular formals collecting corresponding actuals in Extra_Actuals. -- We also generate any required range checks for actuals for in formals -- as we go through the loop, since this is a convenient place to do it. -- (Though it seems that this would be better done in Expand_Actuals???) Formal := First_Formal (Subp); Actual := First_Actual (Call_Node); Param_Count := 1; while Present (Formal) loop -- Generate range check if required if Do_Range_Check (Actual) and then Ekind (Formal) = E_In_Parameter then Set_Do_Range_Check (Actual, False); Generate_Range_Check (Actual, Etype (Formal), CE_Range_Check_Failed); end if; -- Prepare to examine current entry Prev := Actual; Prev_Orig := Original_Node (Prev); -- Ada 2005 (AI-251): Check if any formal is a class-wide interface -- to expand it in a further round. CW_Interface_Formals_Present := CW_Interface_Formals_Present or else (Ekind (Etype (Formal)) = E_Class_Wide_Type and then Is_Interface (Etype (Etype (Formal)))) or else (Ekind (Etype (Formal)) = E_Anonymous_Access_Type and then Is_Interface (Directly_Designated_Type (Etype (Etype (Formal))))); -- Create possible extra actual for constrained case. Usually, the -- extra actual is of the form actual'constrained, but since this -- attribute is only available for unconstrained records, TRUE is -- expanded if the type of the formal happens to be constrained (for -- instance when this procedure is inherited from an unconstrained -- record to a constrained one) or if the actual has no discriminant -- (its type is constrained). An exception to this is the case of a -- private type without discriminants. In this case we pass FALSE -- because the object has underlying discriminants with defaults. if Present (Extra_Constrained (Formal)) then if Ekind (Etype (Prev)) in Private_Kind and then not Has_Discriminants (Base_Type (Etype (Prev))) then Add_Extra_Actual (New_Occurrence_Of (Standard_False, Loc), Extra_Constrained (Formal)); elsif Is_Constrained (Etype (Formal)) or else not Has_Discriminants (Etype (Prev)) then Add_Extra_Actual (New_Occurrence_Of (Standard_True, Loc), Extra_Constrained (Formal)); -- Do not produce extra actuals for Unchecked_Union parameters. -- Jump directly to the end of the loop. elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then goto Skip_Extra_Actual_Generation; else -- If the actual is a type conversion, then the constrained -- test applies to the actual, not the target type. declare Act_Prev : Node_Id; begin -- Test for unchecked conversions as well, which can occur -- as out parameter actuals on calls to stream procedures. Act_Prev := Prev; while Nkind_In (Act_Prev, N_Type_Conversion, N_Unchecked_Type_Conversion) loop Act_Prev := Expression (Act_Prev); end loop; -- If the expression is a conversion of a dereference, this -- is internally generated code that manipulates addresses, -- e.g. when building interface tables. No check should -- occur in this case, and the discriminated object is not -- directly a hand. if not Comes_From_Source (Actual) and then Nkind (Actual) = N_Unchecked_Type_Conversion and then Nkind (Act_Prev) = N_Explicit_Dereference then Add_Extra_Actual (New_Occurrence_Of (Standard_False, Loc), Extra_Constrained (Formal)); else Add_Extra_Actual (Make_Attribute_Reference (Sloc (Prev), Prefix => Duplicate_Subexpr_No_Checks (Act_Prev, Name_Req => True), Attribute_Name => Name_Constrained), Extra_Constrained (Formal)); end if; end; end if; end if; -- Create possible extra actual for accessibility level if Present (Extra_Accessibility (Formal)) then -- Ada 2005 (AI-252): If the actual was rewritten as an Access -- attribute, then the original actual may be an aliased object -- occurring as the prefix in a call using "Object.Operation" -- notation. In that case we must pass the level of the object, -- so Prev_Orig is reset to Prev and the attribute will be -- processed by the code for Access attributes further below. if Prev_Orig /= Prev and then Nkind (Prev) = N_Attribute_Reference and then Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access and then Is_Aliased_View (Prev_Orig) then Prev_Orig := Prev; end if; -- Ada 2005 (AI-251): Thunks must propagate the extra actuals of -- accessibility levels. if Ekind (Current_Scope) in Subprogram_Kind and then Is_Thunk (Current_Scope) then declare Parm_Ent : Entity_Id; begin if Is_Controlling_Actual (Actual) then -- Find the corresponding actual of the thunk Parm_Ent := First_Entity (Current_Scope); for J in 2 .. Param_Count loop Next_Entity (Parm_Ent); end loop; else pragma Assert (Is_Entity_Name (Actual)); Parm_Ent := Entity (Actual); end if; Add_Extra_Actual (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc), Extra_Accessibility (Formal)); end; elsif Is_Entity_Name (Prev_Orig) then -- When passing an access parameter, or a renaming of an access -- parameter, as the actual to another access parameter we need -- to pass along the actual's own access level parameter. This -- is done if we are within the scope of the formal access -- parameter (if this is an inlined body the extra formal is -- irrelevant). if (Is_Formal (Entity (Prev_Orig)) or else (Present (Renamed_Object (Entity (Prev_Orig))) and then Is_Entity_Name (Renamed_Object (Entity (Prev_Orig))) and then Is_Formal (Entity (Renamed_Object (Entity (Prev_Orig)))))) and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type and then In_Open_Scopes (Scope (Entity (Prev_Orig))) then declare Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig); begin pragma Assert (Present (Parm_Ent)); if Present (Extra_Accessibility (Parm_Ent)) then Add_Extra_Actual (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc), Extra_Accessibility (Formal)); -- If the actual access parameter does not have an -- associated extra formal providing its scope level, -- then treat the actual as having library-level -- accessibility. else Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Scope_Depth (Standard_Standard)), Extra_Accessibility (Formal)); end if; end; -- The actual is a normal access value, so just pass the level -- of the actual's access type. else Add_Extra_Actual (Dynamic_Accessibility_Level (Prev_Orig), Extra_Accessibility (Formal)); end if; -- If the actual is an access discriminant, then pass the level -- of the enclosing object (RM05-3.10.2(12.4/2)). elsif Nkind (Prev_Orig) = N_Selected_Component and then Ekind (Entity (Selector_Name (Prev_Orig))) = E_Discriminant and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) = E_Anonymous_Access_Type then Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Object_Access_Level (Prefix (Prev_Orig))), Extra_Accessibility (Formal)); -- All other cases else case Nkind (Prev_Orig) is when N_Attribute_Reference => case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is -- For X'Access, pass on the level of the prefix X when Attribute_Access => -- If this is an Access attribute applied to the -- the current instance object passed to a type -- initialization procedure, then use the level -- of the type itself. This is not really correct, -- as there should be an extra level parameter -- passed in with _init formals (only in the case -- where the type is immutably limited), but we -- don't have an easy way currently to create such -- an extra formal (init procs aren't ever frozen). -- For now we just use the level of the type, -- which may be too shallow, but that works better -- than passing Object_Access_Level of the type, -- which can be one level too deep in some cases. -- ??? if Is_Entity_Name (Prefix (Prev_Orig)) and then Is_Type (Entity (Prefix (Prev_Orig))) then Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Type_Access_Level (Entity (Prefix (Prev_Orig)))), Extra_Accessibility (Formal)); else Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Object_Access_Level (Prefix (Prev_Orig))), Extra_Accessibility (Formal)); end if; -- Treat the unchecked attributes as library-level when Attribute_Unchecked_Access | Attribute_Unrestricted_Access => Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Scope_Depth (Standard_Standard)), Extra_Accessibility (Formal)); -- No other cases of attributes returning access -- values that can be passed to access parameters. when others => raise Program_Error; end case; -- For allocators we pass the level of the execution of the -- called subprogram, which is one greater than the current -- scope level. when N_Allocator => Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Scope_Depth (Current_Scope) + 1), Extra_Accessibility (Formal)); -- For most other cases we simply pass the level of the -- actual's access type. The type is retrieved from -- Prev rather than Prev_Orig, because in some cases -- Prev_Orig denotes an original expression that has -- not been analyzed. when others => Add_Extra_Actual (Dynamic_Accessibility_Level (Prev), Extra_Accessibility (Formal)); end case; end if; end if; -- Perform the check of 4.6(49) that prevents a null value from being -- passed as an actual to an access parameter. Note that the check -- is elided in the common cases of passing an access attribute or -- access parameter as an actual. Also, we currently don't enforce -- this check for expander-generated actuals and when -gnatdj is set. if Ada_Version >= Ada_2005 then -- Ada 2005 (AI-231): Check null-excluding access types. Note that -- the intent of 6.4.1(13) is that null-exclusion checks should -- not be done for 'out' parameters, even though it refers only -- to constraint checks, and a null_exclusion is not a constraint. -- Note that AI05-0196-1 corrects this mistake in the RM. if Is_Access_Type (Etype (Formal)) and then Can_Never_Be_Null (Etype (Formal)) and then Ekind (Formal) /= E_Out_Parameter and then Nkind (Prev) /= N_Raise_Constraint_Error and then (Known_Null (Prev) or else not Can_Never_Be_Null (Etype (Prev))) then Install_Null_Excluding_Check (Prev); end if; -- Ada_Version < Ada_2005 else if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type or else Access_Checks_Suppressed (Subp) then null; elsif Debug_Flag_J then null; elsif not Comes_From_Source (Prev) then null; elsif Is_Entity_Name (Prev) and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type then null; elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then null; -- Suppress null checks when passing to access parameters of Java -- and CIL subprograms. (Should this be done for other foreign -- conventions as well ???) elsif Convention (Subp) = Convention_Java or else Convention (Subp) = Convention_CIL then null; else Install_Null_Excluding_Check (Prev); end if; end if; -- Perform appropriate validity checks on parameters that -- are entities. if Validity_Checks_On then if (Ekind (Formal) = E_In_Parameter and then Validity_Check_In_Params) or else (Ekind (Formal) = E_In_Out_Parameter and then Validity_Check_In_Out_Params) then -- If the actual is an indexed component of a packed type (or -- is an indexed or selected component whose prefix recursively -- meets this condition), it has not been expanded yet. It will -- be copied in the validity code that follows, and has to be -- expanded appropriately, so reanalyze it. -- What we do is just to unset analyzed bits on prefixes till -- we reach something that does not have a prefix. declare Nod : Node_Id; begin Nod := Actual; while Nkind_In (Nod, N_Indexed_Component, N_Selected_Component) loop Set_Analyzed (Nod, False); Nod := Prefix (Nod); end loop; end; Ensure_Valid (Actual); end if; end if; -- For Ada 2012, if a parameter is aliased, the actual must be a -- tagged type or an aliased view of an object. if Is_Aliased (Formal) and then not Is_Aliased_View (Actual) and then not Is_Tagged_Type (Etype (Formal)) then Error_Msg_NE ("actual for aliased formal& must be aliased object", Actual, Formal); end if; -- For IN OUT and OUT parameters, ensure that subscripts are valid -- since this is a left side reference. We only do this for calls -- from the source program since we assume that compiler generated -- calls explicitly generate any required checks. We also need it -- only if we are doing standard validity checks, since clearly it is -- not needed if validity checks are off, and in subscript validity -- checking mode, all indexed components are checked with a call -- directly from Expand_N_Indexed_Component. if Comes_From_Source (Call_Node) and then Ekind (Formal) /= E_In_Parameter and then Validity_Checks_On and then Validity_Check_Default and then not Validity_Check_Subscripts then Check_Valid_Lvalue_Subscripts (Actual); end if; -- Mark any scalar OUT parameter that is a simple variable as no -- longer known to be valid (unless the type is always valid). This -- reflects the fact that if an OUT parameter is never set in a -- procedure, then it can become invalid on the procedure return. if Ekind (Formal) = E_Out_Parameter and then Is_Entity_Name (Actual) and then Ekind (Entity (Actual)) = E_Variable and then not Is_Known_Valid (Etype (Actual)) then Set_Is_Known_Valid (Entity (Actual), False); end if; -- For an OUT or IN OUT parameter, if the actual is an entity, then -- clear current values, since they can be clobbered. We are probably -- doing this in more places than we need to, but better safe than -- sorry when it comes to retaining bad current values! if Ekind (Formal) /= E_In_Parameter and then Is_Entity_Name (Actual) and then Present (Entity (Actual)) then declare Ent : constant Entity_Id := Entity (Actual); Sav : Node_Id; begin -- For an OUT or IN OUT parameter that is an assignable entity, -- we do not want to clobber the Last_Assignment field, since -- if it is set, it was precisely because it is indeed an OUT -- or IN OUT parameter! We do reset the Is_Known_Valid flag -- since the subprogram could have returned in invalid value. if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter) and then Is_Assignable (Ent) then Sav := Last_Assignment (Ent); Kill_Current_Values (Ent); Set_Last_Assignment (Ent, Sav); Set_Is_Known_Valid (Ent, False); -- For all other cases, just kill the current values else Kill_Current_Values (Ent); end if; end; end if; -- If the formal is class wide and the actual is an aggregate, force -- evaluation so that the back end who does not know about class-wide -- type, does not generate a temporary of the wrong size. if not Is_Class_Wide_Type (Etype (Formal)) then null; elsif Nkind (Actual) = N_Aggregate or else (Nkind (Actual) = N_Qualified_Expression and then Nkind (Expression (Actual)) = N_Aggregate) then Force_Evaluation (Actual); end if; -- In a remote call, if the formal is of a class-wide type, check -- that the actual meets the requirements described in E.4(18). if Remote and then Is_Class_Wide_Type (Etype (Formal)) then Insert_Action (Actual, Make_Transportable_Check (Loc, Duplicate_Subexpr_Move_Checks (Actual))); end if; -- This label is required when skipping extra actual generation for -- Unchecked_Union parameters. <<Skip_Extra_Actual_Generation>> Param_Count := Param_Count + 1; Next_Actual (Actual); Next_Formal (Formal); end loop; -- If we are calling an Ada 2012 function which needs to have the -- "accessibility level determined by the point of call" (AI05-0234) -- passed in to it, then pass it in. if Ekind_In (Subp, E_Function, E_Operator, E_Subprogram_Type) and then Present (Extra_Accessibility_Of_Result (Ultimate_Alias (Subp))) then declare Ancestor : Node_Id := Parent (Call_Node); Level : Node_Id := Empty; Defer : Boolean := False; begin -- Unimplemented: if Subp returns an anonymous access type, then -- a) if the call is the operand of an explict conversion, then -- the target type of the conversion (a named access type) -- determines the accessibility level pass in; -- b) if the call defines an access discriminant of an object -- (e.g., the discriminant of an object being created by an -- allocator, or the discriminant of a function result), -- then the accessibility level to pass in is that of the -- discriminated object being initialized). -- ??? while Nkind (Ancestor) = N_Qualified_Expression loop Ancestor := Parent (Ancestor); end loop; case Nkind (Ancestor) is when N_Allocator => -- At this point, we'd like to assign -- Level := Dynamic_Accessibility_Level (Ancestor); -- but Etype of Ancestor may not have been set yet, -- so that doesn't work. -- Handle this later in Expand_Allocator_Expression. Defer := True; when N_Object_Declaration | N_Object_Renaming_Declaration => declare Def_Id : constant Entity_Id := Defining_Identifier (Ancestor); begin if Is_Return_Object (Def_Id) then if Present (Extra_Accessibility_Of_Result (Return_Applies_To (Scope (Def_Id)))) then -- Pass along value that was passed in if the -- routine we are returning from also has an -- Accessibility_Of_Result formal. Level := New_Occurrence_Of (Extra_Accessibility_Of_Result (Return_Applies_To (Scope (Def_Id))), Loc); end if; else Level := Make_Integer_Literal (Loc, Intval => Object_Access_Level (Def_Id)); end if; end; when N_Simple_Return_Statement => if Present (Extra_Accessibility_Of_Result (Return_Applies_To (Return_Statement_Entity (Ancestor)))) then -- Pass along value that was passed in if the routine -- we are returning from also has an -- Accessibility_Of_Result formal. Level := New_Occurrence_Of (Extra_Accessibility_Of_Result (Return_Applies_To (Return_Statement_Entity (Ancestor))), Loc); end if; when others => null; end case; if not Defer then if not Present (Level) then -- The "innermost master that evaluates the function call". -- ??? - Should we use Integer'Last here instead in order -- to deal with (some of) the problems associated with -- calls to subps whose enclosing scope is unknown (e.g., -- Anon_Access_To_Subp_Param.all)? Level := Make_Integer_Literal (Loc, Scope_Depth (Current_Scope) + 1); end if; Add_Extra_Actual (Level, Extra_Accessibility_Of_Result (Ultimate_Alias (Subp))); end if; end; end if; -- If we are expanding a rhs of an assignment we need to check if tag -- propagation is needed. You might expect this processing to be in -- Analyze_Assignment but has to be done earlier (bottom-up) because the -- assignment might be transformed to a declaration for an unconstrained -- value if the expression is classwide. if Nkind (Call_Node) = N_Function_Call and then Is_Tag_Indeterminate (Call_Node) and then Is_Entity_Name (Name (Call_Node)) then declare Ass : Node_Id := Empty; begin if Nkind (Parent (Call_Node)) = N_Assignment_Statement then Ass := Parent (Call_Node); elsif Nkind (Parent (Call_Node)) = N_Qualified_Expression and then Nkind (Parent (Parent (Call_Node))) = N_Assignment_Statement then Ass := Parent (Parent (Call_Node)); elsif Nkind (Parent (Call_Node)) = N_Explicit_Dereference and then Nkind (Parent (Parent (Call_Node))) = N_Assignment_Statement then Ass := Parent (Parent (Call_Node)); end if; if Present (Ass) and then Is_Class_Wide_Type (Etype (Name (Ass))) then if Is_Access_Type (Etype (Call_Node)) then if Designated_Type (Etype (Call_Node)) /= Root_Type (Etype (Name (Ass))) then Error_Msg_NE ("tag-indeterminate expression " & " must have designated type& (RM 5.2 (6))", Call_Node, Root_Type (Etype (Name (Ass)))); else Propagate_Tag (Name (Ass), Call_Node); end if; elsif Etype (Call_Node) /= Root_Type (Etype (Name (Ass))) then Error_Msg_NE ("tag-indeterminate expression must have type&" & "(RM 5.2 (6))", Call_Node, Root_Type (Etype (Name (Ass)))); else Propagate_Tag (Name (Ass), Call_Node); end if; -- The call will be rewritten as a dispatching call, and -- expanded as such. return; end if; end; end if; -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand -- it to point to the correct secondary virtual table if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement) and then CW_Interface_Formals_Present then Expand_Interface_Actuals (Call_Node); end if; -- Deals with Dispatch_Call if we still have a call, before expanding -- extra actuals since this will be done on the re-analysis of the -- dispatching call. Note that we do not try to shorten the actual list -- for a dispatching call, it would not make sense to do so. Expansion -- of dispatching calls is suppressed when VM_Target, because the VM -- back-ends directly handle the generation of dispatching calls and -- would have to undo any expansion to an indirect call. if Nkind_In (Call_Node, N_Function_Call, N_Procedure_Call_Statement) and then Present (Controlling_Argument (Call_Node)) then declare Call_Typ : constant Entity_Id := Etype (Call_Node); Typ : constant Entity_Id := Find_Dispatching_Type (Subp); Eq_Prim_Op : Entity_Id := Empty; New_Call : Node_Id; Param : Node_Id; Prev_Call : Node_Id; begin if not Is_Limited_Type (Typ) then Eq_Prim_Op := Find_Prim_Op (Typ, Name_Op_Eq); end if; if Tagged_Type_Expansion then Expand_Dispatching_Call (Call_Node); -- The following return is worrisome. Is it really OK to skip -- all remaining processing in this procedure ??? return; -- VM targets else Apply_Tag_Checks (Call_Node); -- If this is a dispatching "=", we must first compare the -- tags so we generate: x.tag = y.tag and then x = y if Subp = Eq_Prim_Op then -- Mark the node as analyzed to avoid reanalizing this -- dispatching call (which would cause a never-ending loop) Prev_Call := Relocate_Node (Call_Node); Set_Analyzed (Prev_Call); Param := First_Actual (Call_Node); New_Call := Make_And_Then (Loc, Left_Opnd => Make_Op_Eq (Loc, Left_Opnd => Make_Selected_Component (Loc, Prefix => New_Value (Param), Selector_Name => New_Reference_To (First_Tag_Component (Typ), Loc)), Right_Opnd => Make_Selected_Component (Loc, Prefix => Unchecked_Convert_To (Typ, New_Value (Next_Actual (Param))), Selector_Name => New_Reference_To (First_Tag_Component (Typ), Loc))), Right_Opnd => Prev_Call); Rewrite (Call_Node, New_Call); Analyze_And_Resolve (Call_Node, Call_Typ, Suppress => All_Checks); end if; -- Expansion of a dispatching call results in an indirect call, -- which in turn causes current values to be killed (see -- Resolve_Call), so on VM targets we do the call here to -- ensure consistent warnings between VM and non-VM targets. Kill_Current_Values; end if; -- If this is a dispatching "=" then we must update the reference -- to the call node because we generated: -- x.tag = y.tag and then x = y if Subp = Eq_Prim_Op then Call_Node := Right_Opnd (Call_Node); end if; end; end if; -- Similarly, expand calls to RCI subprograms on which pragma -- All_Calls_Remote applies. The rewriting will be reanalyzed -- later. Do this only when the call comes from source since we -- do not want such a rewriting to occur in expanded code. if Is_All_Remote_Call (Call_Node) then Expand_All_Calls_Remote_Subprogram_Call (Call_Node); -- Similarly, do not add extra actuals for an entry call whose entity -- is a protected procedure, or for an internal protected subprogram -- call, because it will be rewritten as a protected subprogram call -- and reanalyzed (see Expand_Protected_Subprogram_Call). elsif Is_Protected_Type (Scope (Subp)) and then (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function) then null; -- During that loop we gathered the extra actuals (the ones that -- correspond to Extra_Formals), so now they can be appended. else while Is_Non_Empty_List (Extra_Actuals) loop Add_Actual_Parameter (Remove_Head (Extra_Actuals)); end loop; end if; -- At this point we have all the actuals, so this is the point at which -- the various expansion activities for actuals is carried out. Expand_Actuals (Call_Node, Subp); -- If the subprogram is a renaming, or if it is inherited, replace it in -- the call with the name of the actual subprogram being called. If this -- is a dispatching call, the run-time decides what to call. The Alias -- attribute does not apply to entries. if Nkind (Call_Node) /= N_Entry_Call_Statement and then No (Controlling_Argument (Call_Node)) and then Present (Parent_Subp) and then not Is_Direct_Deep_Call (Subp) then if Present (Inherited_From_Formal (Subp)) then Parent_Subp := Inherited_From_Formal (Subp); else Parent_Subp := Ultimate_Alias (Parent_Subp); end if; -- The below setting of Entity is suspect, see F109-018 discussion??? Set_Entity (Name (Call_Node), Parent_Subp); if Is_Abstract_Subprogram (Parent_Subp) and then not In_Instance then Error_Msg_NE ("cannot call abstract subprogram &!", Name (Call_Node), Parent_Subp); end if; -- Inspect all formals of derived subprogram Subp. Compare parameter -- types with the parent subprogram and check whether an actual may -- need a type conversion to the corresponding formal of the parent -- subprogram. -- Not clear whether intrinsic subprograms need such conversions. ??? if not Is_Intrinsic_Subprogram (Parent_Subp) or else Is_Generic_Instance (Parent_Subp) then declare procedure Convert (Act : Node_Id; Typ : Entity_Id); -- Rewrite node Act as a type conversion of Act to Typ. Analyze -- and resolve the newly generated construct. ------------- -- Convert -- ------------- procedure Convert (Act : Node_Id; Typ : Entity_Id) is begin Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act))); Analyze (Act); Resolve (Act, Typ); end Convert; -- Local variables Actual_Typ : Entity_Id; Formal_Typ : Entity_Id; Parent_Typ : Entity_Id; begin Actual := First_Actual (Call_Node); Formal := First_Formal (Subp); Parent_Formal := First_Formal (Parent_Subp); while Present (Formal) loop Actual_Typ := Etype (Actual); Formal_Typ := Etype (Formal); Parent_Typ := Etype (Parent_Formal); -- For an IN parameter of a scalar type, the parent formal -- type and derived formal type differ or the parent formal -- type and actual type do not match statically. if Is_Scalar_Type (Formal_Typ) and then Ekind (Formal) = E_In_Parameter and then Formal_Typ /= Parent_Typ and then not Subtypes_Statically_Match (Parent_Typ, Actual_Typ) and then not Raises_Constraint_Error (Actual) then Convert (Actual, Parent_Typ); Enable_Range_Check (Actual); -- If the actual has been marked as requiring a range -- check, then generate it here. if Do_Range_Check (Actual) then Set_Do_Range_Check (Actual, False); Generate_Range_Check (Actual, Etype (Formal), CE_Range_Check_Failed); end if; -- For access types, the parent formal type and actual type -- differ. elsif Is_Access_Type (Formal_Typ) and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ) then if Ekind (Formal) /= E_In_Parameter then Convert (Actual, Parent_Typ); elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type and then Designated_Type (Parent_Typ) /= Designated_Type (Actual_Typ) and then not Is_Controlling_Formal (Formal) then -- This unchecked conversion is not necessary unless -- inlining is enabled, because in that case the type -- mismatch may become visible in the body about to be -- inlined. Rewrite (Actual, Unchecked_Convert_To (Parent_Typ, Relocate_Node (Actual))); Analyze (Actual); Resolve (Actual, Parent_Typ); end if; -- For array and record types, the parent formal type and -- derived formal type have different sizes or pragma Pack -- status. elsif ((Is_Array_Type (Formal_Typ) and then Is_Array_Type (Parent_Typ)) or else (Is_Record_Type (Formal_Typ) and then Is_Record_Type (Parent_Typ))) and then (Esize (Formal_Typ) /= Esize (Parent_Typ) or else Has_Pragma_Pack (Formal_Typ) /= Has_Pragma_Pack (Parent_Typ)) then Convert (Actual, Parent_Typ); end if; Next_Actual (Actual); Next_Formal (Formal); Next_Formal (Parent_Formal); end loop; end; end if; Orig_Subp := Subp; Subp := Parent_Subp; end if; -- Check for violation of No_Abort_Statements if Restriction_Check_Required (No_Abort_Statements) and then Is_RTE (Subp, RE_Abort_Task) then Check_Restriction (No_Abort_Statements, Call_Node); -- Check for violation of No_Dynamic_Attachment elsif Restriction_Check_Required (No_Dynamic_Attachment) and then RTU_Loaded (Ada_Interrupts) and then (Is_RTE (Subp, RE_Is_Reserved) or else Is_RTE (Subp, RE_Is_Attached) or else Is_RTE (Subp, RE_Current_Handler) or else Is_RTE (Subp, RE_Attach_Handler) or else Is_RTE (Subp, RE_Exchange_Handler) or else Is_RTE (Subp, RE_Detach_Handler) or else Is_RTE (Subp, RE_Reference)) then Check_Restriction (No_Dynamic_Attachment, Call_Node); end if; -- Deal with case where call is an explicit dereference if Nkind (Name (Call_Node)) = N_Explicit_Dereference then -- Handle case of access to protected subprogram type if Is_Access_Protected_Subprogram_Type (Base_Type (Etype (Prefix (Name (Call_Node))))) then -- If this is a call through an access to protected operation, the -- prefix has the form (object'address, operation'access). Rewrite -- as a for other protected calls: the object is the 1st parameter -- of the list of actuals. declare Call : Node_Id; Parm : List_Id; Nam : Node_Id; Obj : Node_Id; Ptr : constant Node_Id := Prefix (Name (Call_Node)); T : constant Entity_Id := Equivalent_Type (Base_Type (Etype (Ptr))); D_T : constant Entity_Id := Designated_Type (Base_Type (Etype (Ptr))); begin Obj := Make_Selected_Component (Loc, Prefix => Unchecked_Convert_To (T, Ptr), Selector_Name => New_Occurrence_Of (First_Entity (T), Loc)); Nam := Make_Selected_Component (Loc, Prefix => Unchecked_Convert_To (T, Ptr), Selector_Name => New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc)); Nam := Make_Explicit_Dereference (Loc, Prefix => Nam); if Present (Parameter_Associations (Call_Node)) then Parm := Parameter_Associations (Call_Node); else Parm := New_List; end if; Prepend (Obj, Parm); if Etype (D_T) = Standard_Void_Type then Call := Make_Procedure_Call_Statement (Loc, Name => Nam, Parameter_Associations => Parm); else Call := Make_Function_Call (Loc, Name => Nam, Parameter_Associations => Parm); end if; Set_First_Named_Actual (Call, First_Named_Actual (Call_Node)); Set_Etype (Call, Etype (D_T)); -- We do not re-analyze the call to avoid infinite recursion. -- We analyze separately the prefix and the object, and set -- the checks on the prefix that would otherwise be emitted -- when resolving a call. Rewrite (Call_Node, Call); Analyze (Nam); Apply_Access_Check (Nam); Analyze (Obj); return; end; end if; end if; -- If this is a call to an intrinsic subprogram, then perform the -- appropriate expansion to the corresponding tree node and we -- are all done (since after that the call is gone!) -- In the case where the intrinsic is to be processed by the back end, -- the call to Expand_Intrinsic_Call will do nothing, which is fine, -- since the idea in this case is to pass the call unchanged. If the -- intrinsic is an inherited unchecked conversion, and the derived type -- is the target type of the conversion, we must retain it as the return -- type of the expression. Otherwise the expansion below, which uses the -- parent operation, will yield the wrong type. if Is_Intrinsic_Subprogram (Subp) then Expand_Intrinsic_Call (Call_Node, Subp); if Nkind (Call_Node) = N_Unchecked_Type_Conversion and then Parent_Subp /= Orig_Subp and then Etype (Parent_Subp) /= Etype (Orig_Subp) then Set_Etype (Call_Node, Etype (Orig_Subp)); end if; return; end if; if Ekind_In (Subp, E_Function, E_Procedure) then -- We perform two simple optimization on calls: -- a) replace calls to null procedures unconditionally; -- b) for To_Address, just do an unchecked conversion. Not only is -- this efficient, but it also avoids order of elaboration problems -- when address clauses are inlined (address expression elaborated -- at the wrong point). -- We perform these optimization regardless of whether we are in the -- main unit or in a unit in the context of the main unit, to ensure -- that tree generated is the same in both cases, for Inspector use. if Is_RTE (Subp, RE_To_Address) then Rewrite (Call_Node, Unchecked_Convert_To (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node)))); return; elsif Is_Null_Procedure (Subp) then Rewrite (Call_Node, Make_Null_Statement (Loc)); return; end if; if Is_Inlined (Subp) then Inlined_Subprogram : declare Bod : Node_Id; Must_Inline : Boolean := False; Spec : constant Node_Id := Unit_Declaration_Node (Subp); Scop : constant Entity_Id := Scope (Subp); function In_Unfrozen_Instance return Boolean; -- If the subprogram comes from an instance in the same unit, -- and the instance is not yet frozen, inlining might trigger -- order-of-elaboration problems in gigi. -------------------------- -- In_Unfrozen_Instance -- -------------------------- function In_Unfrozen_Instance return Boolean is S : Entity_Id; begin S := Scop; while Present (S) and then S /= Standard_Standard loop if Is_Generic_Instance (S) and then Present (Freeze_Node (S)) and then not Analyzed (Freeze_Node (S)) then return True; end if; S := Scope (S); end loop; return False; end In_Unfrozen_Instance; -- Start of processing for Inlined_Subprogram begin -- Verify that the body to inline has already been seen, and -- that if the body is in the current unit the inlining does -- not occur earlier. This avoids order-of-elaboration problems -- in the back end. -- This should be documented in sinfo/einfo ??? if No (Spec) or else Nkind (Spec) /= N_Subprogram_Declaration or else No (Body_To_Inline (Spec)) then Must_Inline := False; -- If this an inherited function that returns a private type, -- do not inline if the full view is an unconstrained array, -- because such calls cannot be inlined. elsif Present (Orig_Subp) and then Is_Array_Type (Etype (Orig_Subp)) and then not Is_Constrained (Etype (Orig_Subp)) then Must_Inline := False; elsif In_Unfrozen_Instance then Must_Inline := False; else Bod := Body_To_Inline (Spec); if (In_Extended_Main_Code_Unit (Call_Node) or else In_Extended_Main_Code_Unit (Parent (Call_Node)) or else Has_Pragma_Inline_Always (Subp)) and then (not In_Same_Extended_Unit (Sloc (Bod), Loc) or else Earlier_In_Extended_Unit (Sloc (Bod), Loc)) then Must_Inline := True; -- If we are compiling a package body that is not the main -- unit, it must be for inlining/instantiation purposes, -- in which case we inline the call to insure that the same -- temporaries are generated when compiling the body by -- itself. Otherwise link errors can occur. -- If the function being called is itself in the main unit, -- we cannot inline, because there is a risk of double -- elaboration and/or circularity: the inlining can make -- visible a private entity in the body of the main unit, -- that gigi will see before its sees its proper definition. elsif not (In_Extended_Main_Code_Unit (Call_Node)) and then In_Package_Body then Must_Inline := not In_Extended_Main_Source_Unit (Subp); end if; end if; if Must_Inline then Expand_Inlined_Call (Call_Node, Subp, Orig_Subp); else -- Let the back end handle it Add_Inlined_Body (Subp); if Front_End_Inlining and then Nkind (Spec) = N_Subprogram_Declaration and then (In_Extended_Main_Code_Unit (Call_Node)) and then No (Body_To_Inline (Spec)) and then not Has_Completion (Subp) and then In_Same_Extended_Unit (Sloc (Spec), Loc) then Cannot_Inline ("cannot inline& (body not seen yet)?", Call_Node, Subp); end if; end if; end Inlined_Subprogram; end if; end if; -- Check for protected subprogram. This is either an intra-object call, -- or a protected function call. Protected procedure calls are rewritten -- as entry calls and handled accordingly. -- In Ada 2005, this may be an indirect call to an access parameter that -- is an access_to_subprogram. In that case the anonymous type has a -- scope that is a protected operation, but the call is a regular one. -- In either case do not expand call if subprogram is eliminated. Scop := Scope (Subp); if Nkind (Call_Node) /= N_Entry_Call_Statement and then Is_Protected_Type (Scop) and then Ekind (Subp) /= E_Subprogram_Type and then not Is_Eliminated (Subp) then -- If the call is an internal one, it is rewritten as a call to the -- corresponding unprotected subprogram. Expand_Protected_Subprogram_Call (Call_Node, Subp, Scop); end if; -- Functions returning controlled objects need special attention. If -- the return type is limited, then the context is initialization and -- different processing applies. If the call is to a protected function, -- the expansion above will call Expand_Call recursively. Otherwise the -- function call is transformed into a temporary which obtains the -- result from the secondary stack. if Needs_Finalization (Etype (Subp)) then if not Is_Immutably_Limited_Type (Etype (Subp)) and then (No (First_Formal (Subp)) or else not Is_Concurrent_Record_Type (Etype (First_Formal (Subp)))) then Expand_Ctrl_Function_Call (Call_Node); -- Build-in-place function calls which appear in anonymous contexts -- need a transient scope to ensure the proper finalization of the -- intermediate result after its use. elsif Is_Build_In_Place_Function_Call (Call_Node) and then Nkind_In (Parent (Call_Node), N_Attribute_Reference, N_Function_Call, N_Indexed_Component, N_Object_Renaming_Declaration, N_Procedure_Call_Statement, N_Selected_Component, N_Slice) then Establish_Transient_Scope (Call_Node, Sec_Stack => True); end if; end if; -- Test for First_Optional_Parameter, and if so, truncate parameter list -- if there are optional parameters at the trailing end. -- Note: we never delete procedures for call via a pointer. if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function) and then Present (First_Optional_Parameter (Subp)) then declare Last_Keep_Arg : Node_Id; begin -- Last_Keep_Arg will hold the last actual that should be kept. -- If it remains empty at the end, it means that all parameters -- are optional. Last_Keep_Arg := Empty; -- Find first optional parameter, must be present since we checked -- the validity of the parameter before setting it. Formal := First_Formal (Subp); Actual := First_Actual (Call_Node); while Formal /= First_Optional_Parameter (Subp) loop Last_Keep_Arg := Actual; Next_Formal (Formal); Next_Actual (Actual); end loop; -- We have Formal and Actual pointing to the first potentially -- droppable argument. We can drop all the trailing arguments -- whose actual matches the default. Note that we know that all -- remaining formals have defaults, because we checked that this -- requirement was met before setting First_Optional_Parameter. -- We use Fully_Conformant_Expressions to check for identity -- between formals and actuals, which may miss some cases, but -- on the other hand, this is only an optimization (if we fail -- to truncate a parameter it does not affect functionality). -- So if the default is 3 and the actual is 1+2, we consider -- them unequal, which hardly seems worrisome. while Present (Formal) loop if not Fully_Conformant_Expressions (Actual, Default_Value (Formal)) then Last_Keep_Arg := Actual; end if; Next_Formal (Formal); Next_Actual (Actual); end loop; -- If no arguments, delete entire list, this is the easy case if No (Last_Keep_Arg) then Set_Parameter_Associations (Call_Node, No_List); Set_First_Named_Actual (Call_Node, Empty); -- Case where at the last retained argument is positional. This -- is also an easy case, since the retained arguments are already -- in the right form, and we don't need to worry about the order -- of arguments that get eliminated. elsif Is_List_Member (Last_Keep_Arg) then while Present (Next (Last_Keep_Arg)) loop Discard_Node (Remove_Next (Last_Keep_Arg)); end loop; Set_First_Named_Actual (Call_Node, Empty); -- This is the annoying case where the last retained argument -- is a named parameter. Since the original arguments are not -- in declaration order, we may have to delete some fairly -- random collection of arguments. else declare Temp : Node_Id; Passoc : Node_Id; begin -- First step, remove all the named parameters from the -- list (they are still chained using First_Named_Actual -- and Next_Named_Actual, so we have not lost them!) Temp := First (Parameter_Associations (Call_Node)); -- Case of all parameters named, remove them all if Nkind (Temp) = N_Parameter_Association then -- Suppress warnings to avoid warning on possible -- infinite loop (because Call_Node is not modified). pragma Warnings (Off); while Is_Non_Empty_List (Parameter_Associations (Call_Node)) loop Temp := Remove_Head (Parameter_Associations (Call_Node)); end loop; pragma Warnings (On); -- Case of mixed positional/named, remove named parameters else while Nkind (Next (Temp)) /= N_Parameter_Association loop Next (Temp); end loop; while Present (Next (Temp)) loop Remove (Next (Temp)); end loop; end if; -- Now we loop through the named parameters, till we get -- to the last one to be retained, adding them to the list. -- Note that the Next_Named_Actual list does not need to be -- touched since we are only reordering them on the actual -- parameter association list. Passoc := Parent (First_Named_Actual (Call_Node)); loop Temp := Relocate_Node (Passoc); Append_To (Parameter_Associations (Call_Node), Temp); exit when Last_Keep_Arg = Explicit_Actual_Parameter (Passoc); Passoc := Parent (Next_Named_Actual (Passoc)); end loop; Set_Next_Named_Actual (Temp, Empty); loop Temp := Next_Named_Actual (Passoc); exit when No (Temp); Set_Next_Named_Actual (Passoc, Next_Named_Actual (Parent (Temp))); end loop; end; end if; end; end if; end Expand_Call; ------------------------------- -- Expand_Ctrl_Function_Call -- ------------------------------- procedure Expand_Ctrl_Function_Call (N : Node_Id) is begin -- Optimization, if the returned value (which is on the sec-stack) is -- returned again, no need to copy/readjust/finalize, we can just pass -- the value thru (see Expand_N_Simple_Return_Statement), and thus no -- attachment is needed if Nkind (Parent (N)) = N_Simple_Return_Statement then return; end if; -- Resolution is now finished, make sure we don't start analysis again -- because of the duplication. Set_Analyzed (N); -- A function which returns a controlled object uses the secondary -- stack. Rewrite the call into a temporary which obtains the result of -- the function using 'reference. Remove_Side_Effects (N); end Expand_Ctrl_Function_Call; -------------------------- -- Expand_Inlined_Call -- -------------------------- procedure Expand_Inlined_Call (N : Node_Id; Subp : Entity_Id; Orig_Subp : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); Is_Predef : constant Boolean := Is_Predefined_File_Name (Unit_File_Name (Get_Source_Unit (Subp))); Orig_Bod : constant Node_Id := Body_To_Inline (Unit_Declaration_Node (Subp)); Blk : Node_Id; Bod : Node_Id; Decl : Node_Id; Decls : constant List_Id := New_List; Exit_Lab : Entity_Id := Empty; F : Entity_Id; A : Node_Id; Lab_Decl : Node_Id; Lab_Id : Node_Id; New_A : Node_Id; Num_Ret : Int := 0; Ret_Type : Entity_Id; Targ : Node_Id; -- The target of the call. If context is an assignment statement then -- this is the left-hand side of the assignment. else it is a temporary -- to which the return value is assigned prior to rewriting the call. Targ1 : Node_Id; -- A separate target used when the return type is unconstrained Temp : Entity_Id; Temp_Typ : Entity_Id; Return_Object : Entity_Id := Empty; -- Entity in declaration in an extended_return_statement Is_Unc : constant Boolean := Is_Array_Type (Etype (Subp)) and then not Is_Constrained (Etype (Subp)); -- If the type returned by the function is unconstrained and the call -- can be inlined, special processing is required. procedure Make_Exit_Label; -- Build declaration for exit label to be used in Return statements, -- sets Exit_Lab (the label node) and Lab_Decl (corresponding implicit -- declaration). Does nothing if Exit_Lab already set. function Process_Formals (N : Node_Id) return Traverse_Result; -- Replace occurrence of a formal with the corresponding actual, or the -- thunk generated for it. function Process_Sloc (Nod : Node_Id) return Traverse_Result; -- If the call being expanded is that of an internal subprogram, set the -- sloc of the generated block to that of the call itself, so that the -- expansion is skipped by the "next" command in gdb. -- Same processing for a subprogram in a predefined file, e.g. -- Ada.Tags. If Debug_Generated_Code is true, suppress this change to -- simplify our own development. procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id); -- If the function body is a single expression, replace call with -- expression, else insert block appropriately. procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id); -- If procedure body has no local variables, inline body without -- creating block, otherwise rewrite call with block. function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean; -- Determine whether a formal parameter is used only once in Orig_Bod --------------------- -- Make_Exit_Label -- --------------------- procedure Make_Exit_Label is Lab_Ent : Entity_Id; begin if No (Exit_Lab) then Lab_Ent := Make_Temporary (Loc, 'L'); Lab_Id := New_Reference_To (Lab_Ent, Loc); Exit_Lab := Make_Label (Loc, Lab_Id); Lab_Decl := Make_Implicit_Label_Declaration (Loc, Defining_Identifier => Lab_Ent, Label_Construct => Exit_Lab); end if; end Make_Exit_Label; --------------------- -- Process_Formals -- --------------------- function Process_Formals (N : Node_Id) return Traverse_Result is A : Entity_Id; E : Entity_Id; Ret : Node_Id; begin if Is_Entity_Name (N) and then Present (Entity (N)) then E := Entity (N); if Is_Formal (E) and then Scope (E) = Subp then A := Renamed_Object (E); -- Rewrite the occurrence of the formal into an occurrence of -- the actual. Also establish visibility on the proper view of -- the actual's subtype for the body's context (if the actual's -- subtype is private at the call point but its full view is -- visible to the body, then the inlined tree here must be -- analyzed with the full view). if Is_Entity_Name (A) then Rewrite (N, New_Occurrence_Of (Entity (A), Loc)); Check_Private_View (N); elsif Nkind (A) = N_Defining_Identifier then Rewrite (N, New_Occurrence_Of (A, Loc)); Check_Private_View (N); -- Numeric literal else Rewrite (N, New_Copy (A)); end if; end if; return Skip; elsif Is_Entity_Name (N) and then Present (Return_Object) and then Chars (N) = Chars (Return_Object) then -- Occurrence within an extended return statement. The return -- object is local to the body been inlined, and thus the generic -- copy is not analyzed yet, so we match by name, and replace it -- with target of call. if Nkind (Targ) = N_Defining_Identifier then Rewrite (N, New_Occurrence_Of (Targ, Loc)); else Rewrite (N, New_Copy_Tree (Targ)); end if; return Skip; elsif Nkind (N) = N_Simple_Return_Statement then if No (Expression (N)) then Make_Exit_Label; Rewrite (N, Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id))); else if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements and then Nkind (Parent (Parent (N))) = N_Subprogram_Body then -- Function body is a single expression. No need for -- exit label. null; else Num_Ret := Num_Ret + 1; Make_Exit_Label; end if; -- Because of the presence of private types, the views of the -- expression and the context may be different, so place an -- unchecked conversion to the context type to avoid spurious -- errors, e.g. when the expression is a numeric literal and -- the context is private. If the expression is an aggregate, -- use a qualified expression, because an aggregate is not a -- legal argument of a conversion. if Nkind_In (Expression (N), N_Aggregate, N_Null) then Ret := Make_Qualified_Expression (Sloc (N), Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)), Expression => Relocate_Node (Expression (N))); else Ret := Unchecked_Convert_To (Ret_Type, Relocate_Node (Expression (N))); end if; if Nkind (Targ) = N_Defining_Identifier then Rewrite (N, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Targ, Loc), Expression => Ret)); else Rewrite (N, Make_Assignment_Statement (Loc, Name => New_Copy (Targ), Expression => Ret)); end if; Set_Assignment_OK (Name (N)); if Present (Exit_Lab) then Insert_After (N, Make_Goto_Statement (Loc, Name => New_Copy (Lab_Id))); end if; end if; return OK; -- An extended return becomes a block whose first statement is the -- assignment of the initial expression of the return object to the -- target of the call itself. elsif Nkind (N) = N_Extended_Return_Statement then declare Return_Decl : constant Entity_Id := First (Return_Object_Declarations (N)); Assign : Node_Id; begin Return_Object := Defining_Identifier (Return_Decl); if Present (Expression (Return_Decl)) then if Nkind (Targ) = N_Defining_Identifier then Assign := Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Targ, Loc), Expression => Expression (Return_Decl)); else Assign := Make_Assignment_Statement (Loc, Name => New_Copy (Targ), Expression => Expression (Return_Decl)); end if; Set_Assignment_OK (Name (Assign)); Prepend (Assign, Statements (Handled_Statement_Sequence (N))); end if; Rewrite (N, Make_Block_Statement (Loc, Handled_Statement_Sequence => Handled_Statement_Sequence (N))); return OK; end; -- Remove pragma Unreferenced since it may refer to formals that -- are not visible in the inlined body, and in any case we will -- not be posting warnings on the inlined body so it is unneeded. elsif Nkind (N) = N_Pragma and then Pragma_Name (N) = Name_Unreferenced then Rewrite (N, Make_Null_Statement (Sloc (N))); return OK; else return OK; end if; end Process_Formals; procedure Replace_Formals is new Traverse_Proc (Process_Formals); ------------------ -- Process_Sloc -- ------------------ function Process_Sloc (Nod : Node_Id) return Traverse_Result is begin if not Debug_Generated_Code then Set_Sloc (Nod, Sloc (N)); Set_Comes_From_Source (Nod, False); end if; return OK; end Process_Sloc; procedure Reset_Slocs is new Traverse_Proc (Process_Sloc); --------------------------- -- Rewrite_Function_Call -- --------------------------- procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is HSS : constant Node_Id := Handled_Statement_Sequence (Blk); Fst : constant Node_Id := First (Statements (HSS)); begin -- Optimize simple case: function body is a single return statement, -- which has been expanded into an assignment. if Is_Empty_List (Declarations (Blk)) and then Nkind (Fst) = N_Assignment_Statement and then No (Next (Fst)) then -- The function call may have been rewritten as the temporary -- that holds the result of the call, in which case remove the -- now useless declaration. if Nkind (N) = N_Identifier and then Nkind (Parent (Entity (N))) = N_Object_Declaration then Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc)); end if; Rewrite (N, Expression (Fst)); elsif Nkind (N) = N_Identifier and then Nkind (Parent (Entity (N))) = N_Object_Declaration then -- The block assigns the result of the call to the temporary Insert_After (Parent (Entity (N)), Blk); -- If the context is an assignment, and the left-hand side is free of -- side-effects, the replacement is also safe. -- Can this be generalized further??? elsif Nkind (Parent (N)) = N_Assignment_Statement and then (Is_Entity_Name (Name (Parent (N))) or else (Nkind (Name (Parent (N))) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (Name (Parent (N))))) or else (Nkind (Name (Parent (N))) = N_Selected_Component and then Is_Entity_Name (Prefix (Name (Parent (N)))))) then -- Replace assignment with the block declare Original_Assignment : constant Node_Id := Parent (N); begin -- Preserve the original assignment node to keep the complete -- assignment subtree consistent enough for Analyze_Assignment -- to proceed (specifically, the original Lhs node must still -- have an assignment statement as its parent). -- We cannot rely on Original_Node to go back from the block -- node to the assignment node, because the assignment might -- already be a rewrite substitution. Discard_Node (Relocate_Node (Original_Assignment)); Rewrite (Original_Assignment, Blk); end; elsif Nkind (Parent (N)) = N_Object_Declaration then Set_Expression (Parent (N), Empty); Insert_After (Parent (N), Blk); elsif Is_Unc then Insert_Before (Parent (N), Blk); end if; end Rewrite_Function_Call; ---------------------------- -- Rewrite_Procedure_Call -- ---------------------------- procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is HSS : constant Node_Id := Handled_Statement_Sequence (Blk); begin -- If there is a transient scope for N, this will be the scope of the -- actions for N, and the statements in Blk need to be within this -- scope. For example, they need to have visibility on the constant -- declarations created for the formals. -- If N needs no transient scope, and if there are no declarations in -- the inlined body, we can do a little optimization and insert the -- statements for the body directly after N, and rewrite N to a -- null statement, instead of rewriting N into a full-blown block -- statement. if not Scope_Is_Transient and then Is_Empty_List (Declarations (Blk)) then Insert_List_After (N, Statements (HSS)); Rewrite (N, Make_Null_Statement (Loc)); else Rewrite (N, Blk); end if; end Rewrite_Procedure_Call; ------------------------- -- Formal_Is_Used_Once -- ------------------------- function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is Use_Counter : Int := 0; function Count_Uses (N : Node_Id) return Traverse_Result; -- Traverse the tree and count the uses of the formal parameter. -- In this case, for optimization purposes, we do not need to -- continue the traversal once more than one use is encountered. ---------------- -- Count_Uses -- ---------------- function Count_Uses (N : Node_Id) return Traverse_Result is begin -- The original node is an identifier if Nkind (N) = N_Identifier and then Present (Entity (N)) -- Original node's entity points to the one in the copied body and then Nkind (Entity (N)) = N_Identifier and then Present (Entity (Entity (N))) -- The entity of the copied node is the formal parameter and then Entity (Entity (N)) = Formal then Use_Counter := Use_Counter + 1; if Use_Counter > 1 then -- Denote more than one use and abandon the traversal Use_Counter := 2; return Abandon; end if; end if; return OK; end Count_Uses; procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses); -- Start of processing for Formal_Is_Used_Once begin Count_Formal_Uses (Orig_Bod); return Use_Counter = 1; end Formal_Is_Used_Once; -- Start of processing for Expand_Inlined_Call begin -- Check for an illegal attempt to inline a recursive procedure. If the -- subprogram has parameters this is detected when trying to supply a -- binding for parameters that already have one. For parameterless -- subprograms this must be done explicitly. if In_Open_Scopes (Subp) then Error_Msg_N ("call to recursive subprogram cannot be inlined?", N); Set_Is_Inlined (Subp, False); return; end if; if Nkind (Orig_Bod) = N_Defining_Identifier or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol then -- Subprogram is renaming_as_body. Calls occurring after the renaming -- can be replaced with calls to the renamed entity directly, because -- the subprograms are subtype conformant. If the renamed subprogram -- is an inherited operation, we must redo the expansion because -- implicit conversions may be needed. Similarly, if the renamed -- entity is inlined, expand the call for further optimizations. Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc)); if Present (Alias (Orig_Bod)) or else Is_Inlined (Orig_Bod) then Expand_Call (N); end if; return; end if; -- Use generic machinery to copy body of inlined subprogram, as if it -- were an instantiation, resetting source locations appropriately, so -- that nested inlined calls appear in the main unit. Save_Env (Subp, Empty); Set_Copied_Sloc_For_Inlined_Body (N, Defining_Entity (Orig_Bod)); Bod := Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True); Blk := Make_Block_Statement (Loc, Declarations => Declarations (Bod), Handled_Statement_Sequence => Handled_Statement_Sequence (Bod)); if No (Declarations (Bod)) then Set_Declarations (Blk, New_List); end if; -- For the unconstrained case, capture the name of the local variable -- that holds the result. This must be the first declaration in the -- block, because its bounds cannot depend on local variables. Otherwise -- there is no way to declare the result outside of the block. Needless -- to say, in general the bounds will depend on the actuals in the call. -- If the context is an assignment statement, as is the case for the -- expansion of an extended return, the left-hand side provides bounds -- even if the return type is unconstrained. if Is_Unc then if Nkind (Parent (N)) /= N_Assignment_Statement then Targ1 := Defining_Identifier (First (Declarations (Blk))); else Targ1 := Name (Parent (N)); end if; end if; -- If this is a derived function, establish the proper return type if Present (Orig_Subp) and then Orig_Subp /= Subp then Ret_Type := Etype (Orig_Subp); else Ret_Type := Etype (Subp); end if; -- Create temporaries for the actuals that are expressions, or that -- are scalars and require copying to preserve semantics. F := First_Formal (Subp); A := First_Actual (N); while Present (F) loop if Present (Renamed_Object (F)) then Error_Msg_N ("cannot inline call to recursive subprogram", N); return; end if; -- If the argument may be a controlling argument in a call within -- the inlined body, we must preserve its classwide nature to insure -- that dynamic dispatching take place subsequently. If the formal -- has a constraint it must be preserved to retain the semantics of -- the body. if Is_Class_Wide_Type (Etype (F)) or else (Is_Access_Type (Etype (F)) and then Is_Class_Wide_Type (Designated_Type (Etype (F)))) then Temp_Typ := Etype (F); elsif Base_Type (Etype (F)) = Base_Type (Etype (A)) and then Etype (F) /= Base_Type (Etype (F)) then Temp_Typ := Etype (F); else Temp_Typ := Etype (A); end if; -- If the actual is a simple name or a literal, no need to -- create a temporary, object can be used directly. -- If the actual is a literal and the formal has its address taken, -- we cannot pass the literal itself as an argument, so its value -- must be captured in a temporary. if (Is_Entity_Name (A) and then (not Is_Scalar_Type (Etype (A)) or else Ekind (Entity (A)) = E_Enumeration_Literal)) -- When the actual is an identifier and the corresponding formal -- is used only once in the original body, the formal can be -- substituted directly with the actual parameter. or else (Nkind (A) = N_Identifier and then Formal_Is_Used_Once (F)) or else (Nkind_In (A, N_Real_Literal, N_Integer_Literal, N_Character_Literal) and then not Address_Taken (F)) then if Etype (F) /= Etype (A) then Set_Renamed_Object (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A))); else Set_Renamed_Object (F, A); end if; else Temp := Make_Temporary (Loc, 'C'); -- If the actual for an in/in-out parameter is a view conversion, -- make it into an unchecked conversion, given that an untagged -- type conversion is not a proper object for a renaming. -- In-out conversions that involve real conversions have already -- been transformed in Expand_Actuals. if Nkind (A) = N_Type_Conversion and then Ekind (F) /= E_In_Parameter then New_A := Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Occurrence_Of (Etype (F), Loc), Expression => Relocate_Node (Expression (A))); elsif Etype (F) /= Etype (A) then New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A)); Temp_Typ := Etype (F); else New_A := Relocate_Node (A); end if; Set_Sloc (New_A, Sloc (N)); -- If the actual has a by-reference type, it cannot be copied, so -- its value is captured in a renaming declaration. Otherwise -- declare a local constant initialized with the actual. -- We also use a renaming declaration for expressions of an array -- type that is not bit-packed, both for efficiency reasons and to -- respect the semantics of the call: in most cases the original -- call will pass the parameter by reference, and thus the inlined -- code will have the same semantics. if Ekind (F) = E_In_Parameter and then not Is_By_Reference_Type (Etype (A)) and then (not Is_Array_Type (Etype (A)) or else not Is_Object_Reference (A) or else Is_Bit_Packed_Array (Etype (A))) then Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Constant_Present => True, Object_Definition => New_Occurrence_Of (Temp_Typ, Loc), Expression => New_A); else Decl := Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Temp, Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc), Name => New_A); end if; Append (Decl, Decls); Set_Renamed_Object (F, Temp); end if; Next_Formal (F); Next_Actual (A); end loop; -- Establish target of function call. If context is not assignment or -- declaration, create a temporary as a target. The declaration for the -- temporary may be subsequently optimized away if the body is a single -- expression, or if the left-hand side of the assignment is simple -- enough, i.e. an entity or an explicit dereference of one. if Ekind (Subp) = E_Function then if Nkind (Parent (N)) = N_Assignment_Statement and then Is_Entity_Name (Name (Parent (N))) then Targ := Name (Parent (N)); elsif Nkind (Parent (N)) = N_Assignment_Statement and then Nkind (Name (Parent (N))) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (Name (Parent (N)))) then Targ := Name (Parent (N)); elsif Nkind (Parent (N)) = N_Assignment_Statement and then Nkind (Name (Parent (N))) = N_Selected_Component and then Is_Entity_Name (Prefix (Name (Parent (N)))) then Targ := New_Copy_Tree (Name (Parent (N))); elsif Nkind (Parent (N)) = N_Object_Declaration and then Is_Limited_Type (Etype (Subp)) then Targ := Defining_Identifier (Parent (N)); else -- Replace call with temporary and create its declaration Temp := Make_Temporary (Loc, 'C'); Set_Is_Internal (Temp); -- For the unconstrained case, the generated temporary has the -- same constrained declaration as the result variable. It may -- eventually be possible to remove that temporary and use the -- result variable directly. if Is_Unc and then Nkind (Parent (N)) /= N_Assignment_Statement then Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Copy_Tree (Object_Definition (Parent (Targ1)))); Replace_Formals (Decl); else Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Occurrence_Of (Ret_Type, Loc)); Set_Etype (Temp, Ret_Type); end if; Set_No_Initialization (Decl); Append (Decl, Decls); Rewrite (N, New_Occurrence_Of (Temp, Loc)); Targ := Temp; end if; end if; Insert_Actions (N, Decls); -- Traverse the tree and replace formals with actuals or their thunks. -- Attach block to tree before analysis and rewriting. Replace_Formals (Blk); Set_Parent (Blk, N); if not Comes_From_Source (Subp) or else Is_Predef then Reset_Slocs (Blk); end if; if Present (Exit_Lab) then -- If the body was a single expression, the single return statement -- and the corresponding label are useless. if Num_Ret = 1 and then Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) = N_Goto_Statement then Remove (Last (Statements (Handled_Statement_Sequence (Blk)))); else Append (Lab_Decl, (Declarations (Blk))); Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk))); end if; end if; -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on -- conflicting private views that Gigi would ignore. If this is a -- predefined unit, analyze with checks off, as is done in the non- -- inlined run-time units. declare I_Flag : constant Boolean := In_Inlined_Body; begin In_Inlined_Body := True; if Is_Predef then declare Style : constant Boolean := Style_Check; begin Style_Check := False; Analyze (Blk, Suppress => All_Checks); Style_Check := Style; end; else Analyze (Blk); end if; In_Inlined_Body := I_Flag; end; if Ekind (Subp) = E_Procedure then Rewrite_Procedure_Call (N, Blk); else Rewrite_Function_Call (N, Blk); -- For the unconstrained case, the replacement of the call has been -- made prior to the complete analysis of the generated declarations. -- Propagate the proper type now. if Is_Unc then if Nkind (N) = N_Identifier then Set_Etype (N, Etype (Entity (N))); else Set_Etype (N, Etype (Targ1)); end if; end if; end if; Restore_Env; -- Cleanup mapping between formals and actuals for other expansions F := First_Formal (Subp); while Present (F) loop Set_Renamed_Object (F, Empty); Next_Formal (F); end loop; end Expand_Inlined_Call; ---------------------------------------- -- Expand_N_Extended_Return_Statement -- ---------------------------------------- -- If there is a Handled_Statement_Sequence, we rewrite this: -- return Result : T := <expression> do -- <handled_seq_of_stms> -- end return; -- to be: -- declare -- Result : T := <expression>; -- begin -- <handled_seq_of_stms> -- return Result; -- end; -- Otherwise (no Handled_Statement_Sequence), we rewrite this: -- return Result : T := <expression>; -- to be: -- return <expression>; -- unless it's build-in-place or there's no <expression>, in which case -- we generate: -- declare -- Result : T := <expression>; -- begin -- return Result; -- end; -- Note that this case could have been written by the user as an extended -- return statement, or could have been transformed to this from a simple -- return statement. -- That is, we need to have a reified return object if there are statements -- (which might refer to it) or if we're doing build-in-place (so we can -- set its address to the final resting place or if there is no expression -- (in which case default initial values might need to be set). procedure Expand_N_Extended_Return_Statement (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Par_Func : constant Entity_Id := Return_Applies_To (Return_Statement_Entity (N)); Result_Subt : constant Entity_Id := Etype (Par_Func); Ret_Obj_Id : constant Entity_Id := First_Entity (Return_Statement_Entity (N)); Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id); Is_Build_In_Place : constant Boolean := Is_Build_In_Place_Function (Par_Func); Exp : Node_Id; HSS : Node_Id; Result : Node_Id; Return_Stmt : Node_Id; Stmts : List_Id; function Build_Heap_Allocator (Temp_Id : Entity_Id; Temp_Typ : Entity_Id; Func_Id : Entity_Id; Ret_Typ : Entity_Id; Alloc_Expr : Node_Id) return Node_Id; -- Create the statements necessary to allocate a return object on the -- caller's master. The master is available through implicit parameter -- BIPfinalizationmaster. -- -- if BIPfinalizationmaster /= null then -- declare -- type Ptr_Typ is access Ret_Typ; -- for Ptr_Typ'Storage_Pool use -- Base_Pool (BIPfinalizationmaster.all).all; -- Local : Ptr_Typ; -- -- begin -- procedure Allocate (...) is -- begin -- System.Storage_Pools.Subpools.Allocate_Any (...); -- end Allocate; -- -- Local := <Alloc_Expr>; -- Temp_Id := Temp_Typ (Local); -- end; -- end if; -- -- Temp_Id is the temporary which is used to reference the internally -- created object in all allocation forms. Temp_Typ is the type of the -- temporary. Func_Id is the enclosing function. Ret_Typ is the return -- type of Func_Id. Alloc_Expr is the actual allocator. function Move_Activation_Chain return Node_Id; -- Construct a call to System.Tasking.Stages.Move_Activation_Chain -- with parameters: -- From current activation chain -- To activation chain passed in by the caller -- New_Master master passed in by the caller -------------------------- -- Build_Heap_Allocator -- -------------------------- function Build_Heap_Allocator (Temp_Id : Entity_Id; Temp_Typ : Entity_Id; Func_Id : Entity_Id; Ret_Typ : Entity_Id; Alloc_Expr : Node_Id) return Node_Id is begin pragma Assert (Is_Build_In_Place_Function (Func_Id)); -- Processing for build-in-place object allocation. This is disabled -- on .NET/JVM because the targets do not support pools. if VM_Target = No_VM and then Needs_Finalization (Ret_Typ) then declare Decls : constant List_Id := New_List; Fin_Mas_Id : constant Entity_Id := Build_In_Place_Formal (Func_Id, BIP_Finalization_Master); Stmts : constant List_Id := New_List; Desig_Typ : Entity_Id; Local_Id : Entity_Id; Pool_Id : Entity_Id; Ptr_Typ : Entity_Id; begin -- Generate: -- Pool_Id renames Base_Pool (BIPfinalizationmaster.all).all; Pool_Id := Make_Temporary (Loc, 'P'); Append_To (Decls, Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Pool_Id, Subtype_Mark => New_Reference_To (RTE (RE_Root_Storage_Pool), Loc), Name => Make_Explicit_Dereference (Loc, Prefix => Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Base_Pool), Loc), Parameter_Associations => New_List ( Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Fin_Mas_Id, Loc))))))); -- Create an access type which uses the storage pool of the -- caller's master. This additional type is necessary because -- the finalization master cannot be associated with the type -- of the temporary. Otherwise the secondary stack allocation -- will fail. Desig_Typ := Ret_Typ; -- Ensure that the build-in-place machinery uses a fat pointer -- when allocating an unconstrained array on the heap. In this -- case the result object type is a constrained array type even -- though the function type is unconstrained. if Ekind (Desig_Typ) = E_Array_Subtype then Desig_Typ := Base_Type (Desig_Typ); end if; -- Generate: -- type Ptr_Typ is access Desig_Typ; Ptr_Typ := Make_Temporary (Loc, 'P'); Append_To (Decls, Make_Full_Type_Declaration (Loc, Defining_Identifier => Ptr_Typ, Type_Definition => Make_Access_To_Object_Definition (Loc, Subtype_Indication => New_Reference_To (Desig_Typ, Loc)))); -- Perform minor decoration in order to set the master and the -- storage pool attributes. Set_Ekind (Ptr_Typ, E_Access_Type); Set_Finalization_Master (Ptr_Typ, Fin_Mas_Id); Set_Associated_Storage_Pool (Ptr_Typ, Pool_Id); -- Create the temporary, generate: -- Local_Id : Ptr_Typ; Local_Id := Make_Temporary (Loc, 'T'); Append_To (Decls, Make_Object_Declaration (Loc, Defining_Identifier => Local_Id, Object_Definition => New_Reference_To (Ptr_Typ, Loc))); -- Allocate the object, generate: -- Local_Id := <Alloc_Expr>; Append_To (Stmts, Make_Assignment_Statement (Loc, Name => New_Reference_To (Local_Id, Loc), Expression => Alloc_Expr)); -- Generate: -- Temp_Id := Temp_Typ (Local_Id); Append_To (Stmts, Make_Assignment_Statement (Loc, Name => New_Reference_To (Temp_Id, Loc), Expression => Unchecked_Convert_To (Temp_Typ, New_Reference_To (Local_Id, Loc)))); -- Wrap the allocation in a block. This is further conditioned -- by checking the caller finalization master at runtime. A -- null value indicates a non-existent master, most likely due -- to a Finalize_Storage_Only allocation. -- Generate: -- if BIPfinalizationmaster /= null then -- declare -- <Decls> -- begin -- <Stmts> -- end; -- end if; return Make_If_Statement (Loc, Condition => Make_Op_Ne (Loc, Left_Opnd => New_Reference_To (Fin_Mas_Id, Loc), Right_Opnd => Make_Null (Loc)), Then_Statements => New_List ( Make_Block_Statement (Loc, Declarations => Decls, Handled_Statement_Sequence => Make_Handled_Sequence_Of_Statements (Loc, Statements => Stmts)))); end; -- For all other cases, generate: -- Temp_Id := <Alloc_Expr>; else return Make_Assignment_Statement (Loc, Name => New_Reference_To (Temp_Id, Loc), Expression => Alloc_Expr); end if; end Build_Heap_Allocator; --------------------------- -- Move_Activation_Chain -- --------------------------- function Move_Activation_Chain return Node_Id is begin return Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Move_Activation_Chain), Loc), Parameter_Associations => New_List ( -- Source chain Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Name_uChain), Attribute_Name => Name_Unrestricted_Access), -- Destination chain New_Reference_To (Build_In_Place_Formal (Par_Func, BIP_Activation_Chain), Loc), -- New master New_Reference_To (Build_In_Place_Formal (Par_Func, BIP_Task_Master), Loc))); end Move_Activation_Chain; -- Start of processing for Expand_N_Extended_Return_Statement begin if Nkind (Ret_Obj_Decl) = N_Object_Declaration then Exp := Expression (Ret_Obj_Decl); else Exp := Empty; end if; HSS := Handled_Statement_Sequence (N); -- If the returned object needs finalization actions, the function must -- perform the appropriate cleanup should it fail to return. The state -- of the function itself is tracked through a flag which is coupled -- with the scope finalizer. There is one flag per each return object -- in case of multiple returns. if Is_Build_In_Place and then Needs_Finalization (Etype (Ret_Obj_Id)) then declare Flag_Decl : Node_Id; Flag_Id : Entity_Id; Func_Bod : Node_Id; begin -- Recover the function body Func_Bod := Unit_Declaration_Node (Par_Func); if Nkind (Func_Bod) = N_Subprogram_Declaration then Func_Bod := Parent (Parent (Corresponding_Body (Func_Bod))); end if; -- Create a flag to track the function state Flag_Id := Make_Temporary (Loc, 'F'); Set_Return_Flag_Or_Transient_Decl (Ret_Obj_Id, Flag_Id); -- Insert the flag at the beginning of the function declarations, -- generate: -- Fnn : Boolean := False; Flag_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Flag_Id, Object_Definition => New_Reference_To (Standard_Boolean, Loc), Expression => New_Reference_To (Standard_False, Loc)); Prepend_To (Declarations (Func_Bod), Flag_Decl); Analyze (Flag_Decl); end; end if; -- Build a simple_return_statement that returns the return object when -- there is a statement sequence, or no expression, or the result will -- be built in place. Note however that we currently do this for all -- composite cases, even though nonlimited composite results are not yet -- built in place (though we plan to do so eventually). if Present (HSS) or else Is_Composite_Type (Result_Subt) or else No (Exp) then if No (HSS) then Stmts := New_List; -- If the extended return has a handled statement sequence, then wrap -- it in a block and use the block as the first statement. else Stmts := New_List ( Make_Block_Statement (Loc, Declarations => New_List, Handled_Statement_Sequence => HSS)); end if; -- If the result type contains tasks, we call Move_Activation_Chain. -- Later, the cleanup code will call Complete_Master, which will -- terminate any unactivated tasks belonging to the return statement -- master. But Move_Activation_Chain updates their master to be that -- of the caller, so they will not be terminated unless the return -- statement completes unsuccessfully due to exception, abort, goto, -- or exit. As a formality, we test whether the function requires the -- result to be built in place, though that's necessarily true for -- the case of result types with task parts. if Is_Build_In_Place and then Has_Task (Result_Subt) then -- The return expression is an aggregate for a complex type which -- contains tasks. This particular case is left unexpanded since -- the regular expansion would insert all temporaries and -- initialization code in the wrong block. if Nkind (Exp) = N_Aggregate then Expand_N_Aggregate (Exp); end if; -- Do not move the activation chain if the return object does not -- contain tasks. if Has_Task (Etype (Ret_Obj_Id)) then Append_To (Stmts, Move_Activation_Chain); end if; end if; -- Update the state of the function right before the object is -- returned. if Is_Build_In_Place and then Needs_Finalization (Etype (Ret_Obj_Id)) then declare Flag_Id : constant Entity_Id := Return_Flag_Or_Transient_Decl (Ret_Obj_Id); begin -- Generate: -- Fnn := True; Append_To (Stmts, Make_Assignment_Statement (Loc, Name => New_Reference_To (Flag_Id, Loc), Expression => New_Reference_To (Standard_True, Loc))); end; end if; -- Build a simple_return_statement that returns the return object Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => New_Occurrence_Of (Ret_Obj_Id, Loc)); Append_To (Stmts, Return_Stmt); HSS := Make_Handled_Sequence_Of_Statements (Loc, Stmts); end if; -- Case where we build a return statement block if Present (HSS) then Result := Make_Block_Statement (Loc, Declarations => Return_Object_Declarations (N), Handled_Statement_Sequence => HSS); -- We set the entity of the new block statement to be that of the -- return statement. This is necessary so that various fields, such -- as Finalization_Chain_Entity carry over from the return statement -- to the block. Note that this block is unusual, in that its entity -- is an E_Return_Statement rather than an E_Block. Set_Identifier (Result, New_Occurrence_Of (Return_Statement_Entity (N), Loc)); -- If the object decl was already rewritten as a renaming, then we -- don't want to do the object allocation and transformation of of -- the return object declaration to a renaming. This case occurs -- when the return object is initialized by a call to another -- build-in-place function, and that function is responsible for -- the allocation of the return object. if Is_Build_In_Place and then Nkind (Ret_Obj_Decl) = N_Object_Renaming_Declaration then pragma Assert (Nkind (Original_Node (Ret_Obj_Decl)) = N_Object_Declaration and then Is_Build_In_Place_Function_Call (Expression (Original_Node (Ret_Obj_Decl)))); -- Return the build-in-place result by reference Set_By_Ref (Return_Stmt); elsif Is_Build_In_Place then -- Locate the implicit access parameter associated with the -- caller-supplied return object and convert the return -- statement's return object declaration to a renaming of a -- dereference of the access parameter. If the return object's -- declaration includes an expression that has not already been -- expanded as separate assignments, then add an assignment -- statement to ensure the return object gets initialized. -- declare -- Result : T [:= <expression>]; -- begin -- ... -- is converted to -- declare -- Result : T renames FuncRA.all; -- [Result := <expression;] -- begin -- ... declare Return_Obj_Id : constant Entity_Id := Defining_Identifier (Ret_Obj_Decl); Return_Obj_Typ : constant Entity_Id := Etype (Return_Obj_Id); Return_Obj_Expr : constant Node_Id := Expression (Ret_Obj_Decl); Constr_Result : constant Boolean := Is_Constrained (Result_Subt); Obj_Alloc_Formal : Entity_Id; Object_Access : Entity_Id; Obj_Acc_Deref : Node_Id; Init_Assignment : Node_Id := Empty; begin -- Build-in-place results must be returned by reference Set_By_Ref (Return_Stmt); -- Retrieve the implicit access parameter passed by the caller Object_Access := Build_In_Place_Formal (Par_Func, BIP_Object_Access); -- If the return object's declaration includes an expression -- and the declaration isn't marked as No_Initialization, then -- we need to generate an assignment to the object and insert -- it after the declaration before rewriting it as a renaming -- (otherwise we'll lose the initialization). The case where -- the result type is an interface (or class-wide interface) -- is also excluded because the context of the function call -- must be unconstrained, so the initialization will always -- be done as part of an allocator evaluation (storage pool -- or secondary stack), never to a constrained target object -- passed in by the caller. Besides the assignment being -- unneeded in this case, it avoids problems with trying to -- generate a dispatching assignment when the return expression -- is a nonlimited descendant of a limited interface (the -- interface has no assignment operation). if Present (Return_Obj_Expr) and then not No_Initialization (Ret_Obj_Decl) and then not Is_Interface (Return_Obj_Typ) then Init_Assignment := Make_Assignment_Statement (Loc, Name => New_Reference_To (Return_Obj_Id, Loc), Expression => Relocate_Node (Return_Obj_Expr)); Set_Etype (Name (Init_Assignment), Etype (Return_Obj_Id)); Set_Assignment_OK (Name (Init_Assignment)); Set_No_Ctrl_Actions (Init_Assignment); Set_Parent (Name (Init_Assignment), Init_Assignment); Set_Parent (Expression (Init_Assignment), Init_Assignment); Set_Expression (Ret_Obj_Decl, Empty); if Is_Class_Wide_Type (Etype (Return_Obj_Id)) and then not Is_Class_Wide_Type (Etype (Expression (Init_Assignment))) then Rewrite (Expression (Init_Assignment), Make_Type_Conversion (Loc, Subtype_Mark => New_Occurrence_Of (Etype (Return_Obj_Id), Loc), Expression => Relocate_Node (Expression (Init_Assignment)))); end if; -- In the case of functions where the calling context can -- determine the form of allocation needed, initialization -- is done with each part of the if statement that handles -- the different forms of allocation (this is true for -- unconstrained and tagged result subtypes). if Constr_Result and then not Is_Tagged_Type (Underlying_Type (Result_Subt)) then Insert_After (Ret_Obj_Decl, Init_Assignment); end if; end if; -- When the function's subtype is unconstrained, a run-time -- test is needed to determine the form of allocation to use -- for the return object. The function has an implicit formal -- parameter indicating this. If the BIP_Alloc_Form formal has -- the value one, then the caller has passed access to an -- existing object for use as the return object. If the value -- is two, then the return object must be allocated on the -- secondary stack. Otherwise, the object must be allocated in -- a storage pool (currently only supported for the global -- heap, user-defined storage pools TBD ???). We generate an -- if statement to test the implicit allocation formal and -- initialize a local access value appropriately, creating -- allocators in the secondary stack and global heap cases. -- The special formal also exists and must be tested when the -- function has a tagged result, even when the result subtype -- is constrained, because in general such functions can be -- called in dispatching contexts and must be handled similarly -- to functions with a class-wide result. if not Constr_Result or else Is_Tagged_Type (Underlying_Type (Result_Subt)) then Obj_Alloc_Formal := Build_In_Place_Formal (Par_Func, BIP_Alloc_Form); declare Pool_Id : constant Entity_Id := Make_Temporary (Loc, 'P'); Alloc_Obj_Id : Entity_Id; Alloc_Obj_Decl : Node_Id; Alloc_If_Stmt : Node_Id; Heap_Allocator : Node_Id; Pool_Decl : Node_Id; Pool_Allocator : Node_Id; Ptr_Type_Decl : Node_Id; Ref_Type : Entity_Id; SS_Allocator : Node_Id; begin -- Reuse the itype created for the function's implicit -- access formal. This avoids the need to create a new -- access type here, plus it allows assigning the access -- formal directly without applying a conversion. -- Ref_Type := Etype (Object_Access); -- Create an access type designating the function's -- result subtype. Ref_Type := Make_Temporary (Loc, 'A'); Ptr_Type_Decl := Make_Full_Type_Declaration (Loc, Defining_Identifier => Ref_Type, Type_Definition => Make_Access_To_Object_Definition (Loc, All_Present => True, Subtype_Indication => New_Reference_To (Return_Obj_Typ, Loc))); Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl); -- Create an access object that will be initialized to an -- access value denoting the return object, either coming -- from an implicit access value passed in by the caller -- or from the result of an allocator. Alloc_Obj_Id := Make_Temporary (Loc, 'R'); Set_Etype (Alloc_Obj_Id, Ref_Type); Alloc_Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Alloc_Obj_Id, Object_Definition => New_Reference_To (Ref_Type, Loc)); Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl); -- Create allocators for both the secondary stack and -- global heap. If there's an initialization expression, -- then create these as initialized allocators. if Present (Return_Obj_Expr) and then not No_Initialization (Ret_Obj_Decl) then -- Always use the type of the expression for the -- qualified expression, rather than the result type. -- In general we cannot always use the result type -- for the allocator, because the expression might be -- of a specific type, such as in the case of an -- aggregate or even a nonlimited object when the -- result type is a limited class-wide interface type. Heap_Allocator := Make_Allocator (Loc, Expression => Make_Qualified_Expression (Loc, Subtype_Mark => New_Reference_To (Etype (Return_Obj_Expr), Loc), Expression => New_Copy_Tree (Return_Obj_Expr))); else -- If the function returns a class-wide type we cannot -- use the return type for the allocator. Instead we -- use the type of the expression, which must be an -- aggregate of a definite type. if Is_Class_Wide_Type (Return_Obj_Typ) then Heap_Allocator := Make_Allocator (Loc, Expression => New_Reference_To (Etype (Return_Obj_Expr), Loc)); else Heap_Allocator := Make_Allocator (Loc, Expression => New_Reference_To (Return_Obj_Typ, Loc)); end if; -- If the object requires default initialization then -- that will happen later following the elaboration of -- the object renaming. If we don't turn it off here -- then the object will be default initialized twice. Set_No_Initialization (Heap_Allocator); end if; -- The Pool_Allocator is just like the Heap_Allocator, -- except we set Storage_Pool and Procedure_To_Call so -- it will use the user-defined storage pool. Pool_Allocator := New_Copy_Tree (Heap_Allocator); -- Do not generate the renaming of the build-in-place -- pool parameter on .NET/JVM/ZFP because the parameter -- is not created in the first place. if VM_Target = No_VM and then RTE_Available (RE_Root_Storage_Pool_Ptr) then Pool_Decl := Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Pool_Id, Subtype_Mark => New_Reference_To (RTE (RE_Root_Storage_Pool), Loc), Name => Make_Explicit_Dereference (Loc, New_Reference_To (Build_In_Place_Formal (Par_Func, BIP_Storage_Pool), Loc))); Set_Storage_Pool (Pool_Allocator, Pool_Id); Set_Procedure_To_Call (Pool_Allocator, RTE (RE_Allocate_Any)); else Pool_Decl := Make_Null_Statement (Loc); end if; -- If the No_Allocators restriction is active, then only -- an allocator for secondary stack allocation is needed. -- It's OK for such allocators to have Comes_From_Source -- set to False, because gigi knows not to flag them as -- being a violation of No_Implicit_Heap_Allocations. if Restriction_Active (No_Allocators) then SS_Allocator := Heap_Allocator; Heap_Allocator := Make_Null (Loc); Pool_Allocator := Make_Null (Loc); -- Otherwise the heap and pool allocators may be needed, -- so we make another allocator for secondary stack -- allocation. else SS_Allocator := New_Copy_Tree (Heap_Allocator); -- The heap and pool allocators are marked as -- Comes_From_Source since they correspond to an -- explicit user-written allocator (that is, it will -- only be executed on behalf of callers that call the -- function as initialization for such an allocator). -- Prevents errors when No_Implicit_Heap_Allocations -- is in force. Set_Comes_From_Source (Heap_Allocator, True); Set_Comes_From_Source (Pool_Allocator, True); end if; -- The allocator is returned on the secondary stack. We -- don't do this on VM targets, since the SS is not used. if VM_Target = No_VM then Set_Storage_Pool (SS_Allocator, RTE (RE_SS_Pool)); Set_Procedure_To_Call (SS_Allocator, RTE (RE_SS_Allocate)); -- The allocator is returned on the secondary stack, -- so indicate that the function return, as well as -- the block that encloses the allocator, must not -- release it. The flags must be set now because -- the decision to use the secondary stack is done -- very late in the course of expanding the return -- statement, past the point where these flags are -- normally set. Set_Sec_Stack_Needed_For_Return (Par_Func); Set_Sec_Stack_Needed_For_Return (Return_Statement_Entity (N)); Set_Uses_Sec_Stack (Par_Func); Set_Uses_Sec_Stack (Return_Statement_Entity (N)); end if; -- Create an if statement to test the BIP_Alloc_Form -- formal and initialize the access object to either the -- BIP_Object_Access formal (BIP_Alloc_Form = -- Caller_Allocation), the result of allocating the -- object in the secondary stack (BIP_Alloc_Form = -- Secondary_Stack), or else an allocator to create the -- return object in the heap or user-defined pool -- (BIP_Alloc_Form = Global_Heap or User_Storage_Pool). -- ??? An unchecked type conversion must be made in the -- case of assigning the access object formal to the -- local access object, because a normal conversion would -- be illegal in some cases (such as converting access- -- to-unconstrained to access-to-constrained), but the -- the unchecked conversion will presumably fail to work -- right in just such cases. It's not clear at all how to -- handle this. ??? Alloc_If_Stmt := Make_If_Statement (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Reference_To (Obj_Alloc_Formal, Loc), Right_Opnd => Make_Integer_Literal (Loc, UI_From_Int (BIP_Allocation_Form'Pos (Caller_Allocation)))), Then_Statements => New_List ( Make_Assignment_Statement (Loc, Name => New_Reference_To (Alloc_Obj_Id, Loc), Expression => Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Ref_Type, Loc), Expression => New_Reference_To (Object_Access, Loc)))), Elsif_Parts => New_List ( Make_Elsif_Part (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Reference_To (Obj_Alloc_Formal, Loc), Right_Opnd => Make_Integer_Literal (Loc, UI_From_Int (BIP_Allocation_Form'Pos (Secondary_Stack)))), Then_Statements => New_List ( Make_Assignment_Statement (Loc, Name => New_Reference_To (Alloc_Obj_Id, Loc), Expression => SS_Allocator))), Make_Elsif_Part (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Reference_To (Obj_Alloc_Formal, Loc), Right_Opnd => Make_Integer_Literal (Loc, UI_From_Int (BIP_Allocation_Form'Pos (Global_Heap)))), Then_Statements => New_List ( Build_Heap_Allocator (Temp_Id => Alloc_Obj_Id, Temp_Typ => Ref_Type, Func_Id => Par_Func, Ret_Typ => Return_Obj_Typ, Alloc_Expr => Heap_Allocator)))), Else_Statements => New_List ( Pool_Decl, Build_Heap_Allocator (Temp_Id => Alloc_Obj_Id, Temp_Typ => Ref_Type, Func_Id => Par_Func, Ret_Typ => Return_Obj_Typ, Alloc_Expr => Pool_Allocator))); -- If a separate initialization assignment was created -- earlier, append that following the assignment of the -- implicit access formal to the access object, to ensure -- that the return object is initialized in that case. In -- this situation, the target of the assignment must be -- rewritten to denote a dereference of the access to the -- return object passed in by the caller. if Present (Init_Assignment) then Rewrite (Name (Init_Assignment), Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Alloc_Obj_Id, Loc))); Set_Etype (Name (Init_Assignment), Etype (Return_Obj_Id)); Append_To (Then_Statements (Alloc_If_Stmt), Init_Assignment); end if; Insert_Before (Ret_Obj_Decl, Alloc_If_Stmt); -- Remember the local access object for use in the -- dereference of the renaming created below. Object_Access := Alloc_Obj_Id; end; end if; -- Replace the return object declaration with a renaming of a -- dereference of the access value designating the return -- object. Obj_Acc_Deref := Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Object_Access, Loc)); Rewrite (Ret_Obj_Decl, Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Return_Obj_Id, Access_Definition => Empty, Subtype_Mark => New_Occurrence_Of (Return_Obj_Typ, Loc), Name => Obj_Acc_Deref)); Set_Renamed_Object (Return_Obj_Id, Obj_Acc_Deref); end; end if; -- Case where we do not build a block else -- We're about to drop Return_Object_Declarations on the floor, so -- we need to insert it, in case it got expanded into useful code. -- Remove side effects from expression, which may be duplicated in -- subsequent checks (see Expand_Simple_Function_Return). Insert_List_Before (N, Return_Object_Declarations (N)); Remove_Side_Effects (Exp); -- Build simple_return_statement that returns the expression directly Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => Exp); Result := Return_Stmt; end if; -- Set the flag to prevent infinite recursion Set_Comes_From_Extended_Return_Statement (Return_Stmt); Rewrite (N, Result); Analyze (N); end Expand_N_Extended_Return_Statement; ---------------------------- -- Expand_N_Function_Call -- ---------------------------- procedure Expand_N_Function_Call (N : Node_Id) is begin Expand_Call (N); -- If the return value of a foreign compiled function is VAX Float, then -- expand the return (adjusts the location of the return value on -- Alpha/VMS, no-op everywhere else). -- Comes_From_Source intercepts recursive expansion. if Vax_Float (Etype (N)) and then Nkind (N) = N_Function_Call and then Present (Name (N)) and then Present (Entity (Name (N))) and then Has_Foreign_Convention (Entity (Name (N))) and then Comes_From_Source (Parent (N)) then Expand_Vax_Foreign_Return (N); end if; end Expand_N_Function_Call; --------------------------------------- -- Expand_N_Procedure_Call_Statement -- --------------------------------------- procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is begin Expand_Call (N); end Expand_N_Procedure_Call_Statement; -------------------------------------- -- Expand_N_Simple_Return_Statement -- -------------------------------------- procedure Expand_N_Simple_Return_Statement (N : Node_Id) is begin -- Defend against previous errors (i.e. the return statement calls a -- function that is not available in configurable runtime). if Present (Expression (N)) and then Nkind (Expression (N)) = N_Empty then return; end if; -- Distinguish the function and non-function cases: case Ekind (Return_Applies_To (Return_Statement_Entity (N))) is when E_Function | E_Generic_Function => Expand_Simple_Function_Return (N); when E_Procedure | E_Generic_Procedure | E_Entry | E_Entry_Family | E_Return_Statement => Expand_Non_Function_Return (N); when others => raise Program_Error; end case; exception when RE_Not_Available => return; end Expand_N_Simple_Return_Statement; ------------------------------ -- Expand_N_Subprogram_Body -- ------------------------------ -- Add poll call if ATC polling is enabled, unless the body will be inlined -- by the back-end. -- Add dummy push/pop label nodes at start and end to clear any local -- exception indications if local-exception-to-goto optimization is active. -- Add return statement if last statement in body is not a return statement -- (this makes things easier on Gigi which does not want to have to handle -- a missing return). -- Add call to Activate_Tasks if body is a task activator -- Deal with possible detection of infinite recursion -- Eliminate body completely if convention stubbed -- Encode entity names within body, since we will not need to reference -- these entities any longer in the front end. -- Initialize scalar out parameters if Initialize/Normalize_Scalars -- Reset Pure indication if any parameter has root type System.Address -- or has any parameters of limited types, where limited means that the -- run-time view is limited (i.e. the full type is limited). -- Wrap thread body procedure Expand_N_Subprogram_Body (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); H : constant Node_Id := Handled_Statement_Sequence (N); Body_Id : Entity_Id; Except_H : Node_Id; L : List_Id; Spec_Id : Entity_Id; procedure Add_Return (S : List_Id); -- Append a return statement to the statement sequence S if the last -- statement is not already a return or a goto statement. Note that -- the latter test is not critical, it does not matter if we add a few -- extra returns, since they get eliminated anyway later on. ---------------- -- Add_Return -- ---------------- procedure Add_Return (S : List_Id) is Last_Stm : Node_Id; Loc : Source_Ptr; begin -- Get last statement, ignoring any Pop_xxx_Label nodes, which are -- not relevant in this context since they are not executable. Last_Stm := Last (S); while Nkind (Last_Stm) in N_Pop_xxx_Label loop Prev (Last_Stm); end loop; -- Now insert return unless last statement is a transfer if not Is_Transfer (Last_Stm) then -- The source location for the return is the end label of the -- procedure if present. Otherwise use the sloc of the last -- statement in the list. If the list comes from a generated -- exception handler and we are not debugging generated code, -- all the statements within the handler are made invisible -- to the debugger. if Nkind (Parent (S)) = N_Exception_Handler and then not Comes_From_Source (Parent (S)) then Loc := Sloc (Last_Stm); elsif Present (End_Label (H)) then Loc := Sloc (End_Label (H)); else Loc := Sloc (Last_Stm); end if; declare Rtn : constant Node_Id := Make_Simple_Return_Statement (Loc); begin -- Append return statement, and set analyzed manually. We can't -- call Analyze on this return since the scope is wrong. -- Note: it almost works to push the scope and then do the -- Analyze call, but something goes wrong in some weird cases -- and it is not worth worrying about ??? Append_To (S, Rtn); Set_Analyzed (Rtn); -- Call _Postconditions procedure if appropriate. We need to -- do this explicitly because we did not analyze the generated -- return statement above, so the call did not get inserted. if Ekind (Spec_Id) = E_Procedure and then Has_Postconditions (Spec_Id) then pragma Assert (Present (Postcondition_Proc (Spec_Id))); Insert_Action (Rtn, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (Postcondition_Proc (Spec_Id), Loc))); end if; end; end if; end Add_Return; -- Start of processing for Expand_N_Subprogram_Body begin -- Set L to either the list of declarations if present, or to the list -- of statements if no declarations are present. This is used to insert -- new stuff at the start. if Is_Non_Empty_List (Declarations (N)) then L := Declarations (N); else L := Statements (H); end if; -- If local-exception-to-goto optimization active, insert dummy push -- statements at start, and dummy pop statements at end, but inhibit -- this if we have No_Exception_Handlers, since they are useless and -- intefere with analysis, e.g. by codepeer. if (Debug_Flag_Dot_G or else Restriction_Active (No_Exception_Propagation)) and then not Restriction_Active (No_Exception_Handlers) and then not CodePeer_Mode and then Is_Non_Empty_List (L) then declare FS : constant Node_Id := First (L); FL : constant Source_Ptr := Sloc (FS); LS : Node_Id; LL : Source_Ptr; begin -- LS points to either last statement, if statements are present -- or to the last declaration if there are no statements present. -- It is the node after which the pop's are generated. if Is_Non_Empty_List (Statements (H)) then LS := Last (Statements (H)); else LS := Last (L); end if; LL := Sloc (LS); Insert_List_Before_And_Analyze (FS, New_List ( Make_Push_Constraint_Error_Label (FL), Make_Push_Program_Error_Label (FL), Make_Push_Storage_Error_Label (FL))); Insert_List_After_And_Analyze (LS, New_List ( Make_Pop_Constraint_Error_Label (LL), Make_Pop_Program_Error_Label (LL), Make_Pop_Storage_Error_Label (LL))); end; end if; -- Find entity for subprogram Body_Id := Defining_Entity (N); if Present (Corresponding_Spec (N)) then Spec_Id := Corresponding_Spec (N); else Spec_Id := Body_Id; end if; -- Need poll on entry to subprogram if polling enabled. We only do this -- for non-empty subprograms, since it does not seem necessary to poll -- for a dummy null subprogram. if Is_Non_Empty_List (L) then -- Do not add a polling call if the subprogram is to be inlined by -- the back-end, to avoid repeated calls with multiple inlinings. if Is_Inlined (Spec_Id) and then Front_End_Inlining and then Optimization_Level > 1 then null; else Generate_Poll_Call (First (L)); end if; end if; -- If this is a Pure function which has any parameters whose root type -- is System.Address, reset the Pure indication, since it will likely -- cause incorrect code to be generated as the parameter is probably -- a pointer, and the fact that the same pointer is passed does not mean -- that the same value is being referenced. -- Note that if the programmer gave an explicit Pure_Function pragma, -- then we believe the programmer, and leave the subprogram Pure. -- This code should probably be at the freeze point, so that it happens -- even on a -gnatc (or more importantly -gnatt) compile, so that the -- semantic tree has Is_Pure set properly ??? if Is_Pure (Spec_Id) and then Is_Subprogram (Spec_Id) and then not Has_Pragma_Pure_Function (Spec_Id) then declare F : Entity_Id; begin F := First_Formal (Spec_Id); while Present (F) loop if Is_Descendent_Of_Address (Etype (F)) -- Note that this test is being made in the body of the -- subprogram, not the spec, so we are testing the full -- type for being limited here, as required. or else Is_Limited_Type (Etype (F)) then Set_Is_Pure (Spec_Id, False); if Spec_Id /= Body_Id then Set_Is_Pure (Body_Id, False); end if; exit; end if; Next_Formal (F); end loop; end; end if; -- Initialize any scalar OUT args if Initialize/Normalize_Scalars if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then declare F : Entity_Id; begin -- Loop through formals F := First_Formal (Spec_Id); while Present (F) loop if Is_Scalar_Type (Etype (F)) and then Ekind (F) = E_Out_Parameter then Check_Restriction (No_Default_Initialization, F); -- Insert the initialization. We turn off validity checks -- for this assignment, since we do not want any check on -- the initial value itself (which may well be invalid). Insert_Before_And_Analyze (First (L), Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (F, Loc), Expression => Get_Simple_Init_Val (Etype (F), N)), Suppress => Validity_Check); end if; Next_Formal (F); end loop; end; end if; -- Clear out statement list for stubbed procedure if Present (Corresponding_Spec (N)) then Set_Elaboration_Flag (N, Spec_Id); if Convention (Spec_Id) = Convention_Stubbed or else Is_Eliminated (Spec_Id) then Set_Declarations (N, Empty_List); Set_Handled_Statement_Sequence (N, Make_Handled_Sequence_Of_Statements (Loc, Statements => New_List (Make_Null_Statement (Loc)))); return; end if; end if; -- Create a set of discriminals for the next protected subprogram body if Is_List_Member (N) and then Present (Parent (List_Containing (N))) and then Nkind (Parent (List_Containing (N))) = N_Protected_Body and then Present (Next_Protected_Operation (N)) then Set_Discriminals (Parent (Base_Type (Scope (Spec_Id)))); end if; -- Returns_By_Ref flag is normally set when the subprogram is frozen but -- subprograms with no specs are not frozen. declare Typ : constant Entity_Id := Etype (Spec_Id); Utyp : constant Entity_Id := Underlying_Type (Typ); begin if not Acts_As_Spec (N) and then Nkind (Parent (Parent (Spec_Id))) /= N_Subprogram_Body_Stub then null; elsif Is_Immutably_Limited_Type (Typ) then Set_Returns_By_Ref (Spec_Id); elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then Set_Returns_By_Ref (Spec_Id); end if; end; -- For a procedure, we add a return for all possible syntactic ends of -- the subprogram. if Ekind_In (Spec_Id, E_Procedure, E_Generic_Procedure) then Add_Return (Statements (H)); if Present (Exception_Handlers (H)) then Except_H := First_Non_Pragma (Exception_Handlers (H)); while Present (Except_H) loop Add_Return (Statements (Except_H)); Next_Non_Pragma (Except_H); end loop; end if; -- For a function, we must deal with the case where there is at least -- one missing return. What we do is to wrap the entire body of the -- function in a block: -- begin -- ... -- end; -- becomes -- begin -- begin -- ... -- end; -- raise Program_Error; -- end; -- This approach is necessary because the raise must be signalled to the -- caller, not handled by any local handler (RM 6.4(11)). -- Note: we do not need to analyze the constructed sequence here, since -- it has no handler, and an attempt to analyze the handled statement -- sequence twice is risky in various ways (e.g. the issue of expanding -- cleanup actions twice). elsif Has_Missing_Return (Spec_Id) then declare Hloc : constant Source_Ptr := Sloc (H); Blok : constant Node_Id := Make_Block_Statement (Hloc, Handled_Statement_Sequence => H); Rais : constant Node_Id := Make_Raise_Program_Error (Hloc, Reason => PE_Missing_Return); begin Set_Handled_Statement_Sequence (N, Make_Handled_Sequence_Of_Statements (Hloc, Statements => New_List (Blok, Rais))); Push_Scope (Spec_Id); Analyze (Blok); Analyze (Rais); Pop_Scope; end; end if; -- If subprogram contains a parameterless recursive call, then we may -- have an infinite recursion, so see if we can generate code to check -- for this possibility if storage checks are not suppressed. if Ekind (Spec_Id) = E_Procedure and then Has_Recursive_Call (Spec_Id) and then not Storage_Checks_Suppressed (Spec_Id) then Detect_Infinite_Recursion (N, Spec_Id); end if; -- Set to encode entity names in package body before gigi is called Qualify_Entity_Names (N); end Expand_N_Subprogram_Body; ----------------------------------- -- Expand_N_Subprogram_Body_Stub -- ----------------------------------- procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is begin if Present (Corresponding_Body (N)) then Expand_N_Subprogram_Body ( Unit_Declaration_Node (Corresponding_Body (N))); end if; end Expand_N_Subprogram_Body_Stub; ------------------------------------- -- Expand_N_Subprogram_Declaration -- ------------------------------------- -- If the declaration appears within a protected body, it is a private -- operation of the protected type. We must create the corresponding -- protected subprogram an associated formals. For a normal protected -- operation, this is done when expanding the protected type declaration. -- If the declaration is for a null procedure, emit null body procedure Expand_N_Subprogram_Declaration (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Subp : constant Entity_Id := Defining_Entity (N); Scop : constant Entity_Id := Scope (Subp); Prot_Decl : Node_Id; Prot_Bod : Node_Id; Prot_Id : Entity_Id; begin -- In SPARK, subprogram declarations are only allowed in package -- specifications. if Nkind (Parent (N)) /= N_Package_Specification then if Nkind (Parent (N)) = N_Compilation_Unit then Check_SPARK_Restriction ("subprogram declaration is not a library item", N); elsif Present (Next (N)) and then Nkind (Next (N)) = N_Pragma and then Get_Pragma_Id (Pragma_Name (Next (N))) = Pragma_Import then -- In SPARK, subprogram declarations are also permitted in -- declarative parts when immediately followed by a corresponding -- pragma Import. We only check here that there is some pragma -- Import. null; else Check_SPARK_Restriction ("subprogram declaration is not allowed here", N); end if; end if; -- Deal with case of protected subprogram. Do not generate protected -- operation if operation is flagged as eliminated. if Is_List_Member (N) and then Present (Parent (List_Containing (N))) and then Nkind (Parent (List_Containing (N))) = N_Protected_Body and then Is_Protected_Type (Scop) then if No (Protected_Body_Subprogram (Subp)) and then not Is_Eliminated (Subp) then Prot_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Protected_Sub_Specification (N, Scop, Unprotected_Mode)); -- The protected subprogram is declared outside of the protected -- body. Given that the body has frozen all entities so far, we -- analyze the subprogram and perform freezing actions explicitly. -- including the generation of an explicit freeze node, to ensure -- that gigi has the proper order of elaboration. -- If the body is a subunit, the insertion point is before the -- stub in the parent. Prot_Bod := Parent (List_Containing (N)); if Nkind (Parent (Prot_Bod)) = N_Subunit then Prot_Bod := Corresponding_Stub (Parent (Prot_Bod)); end if; Insert_Before (Prot_Bod, Prot_Decl); Prot_Id := Defining_Unit_Name (Specification (Prot_Decl)); Set_Has_Delayed_Freeze (Prot_Id); Push_Scope (Scope (Scop)); Analyze (Prot_Decl); Freeze_Before (N, Prot_Id); Set_Protected_Body_Subprogram (Subp, Prot_Id); -- Create protected operation as well. Even though the operation -- is only accessible within the body, it is possible to make it -- available outside of the protected object by using 'Access to -- provide a callback, so build protected version in all cases. Prot_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Protected_Sub_Specification (N, Scop, Protected_Mode)); Insert_Before (Prot_Bod, Prot_Decl); Analyze (Prot_Decl); Pop_Scope; end if; -- Ada 2005 (AI-348): Generate body for a null procedure. In most -- cases this is superfluous because calls to it will be automatically -- inlined, but we definitely need the body if preconditions for the -- procedure are present. elsif Nkind (Specification (N)) = N_Procedure_Specification and then Null_Present (Specification (N)) then declare Bod : constant Node_Id := Body_To_Inline (N); begin Set_Has_Completion (Subp, False); Append_Freeze_Action (Subp, Bod); -- The body now contains raise statements, so calls to it will -- not be inlined. Set_Is_Inlined (Subp, False); end; end if; end Expand_N_Subprogram_Declaration; -------------------------------- -- Expand_Non_Function_Return -- -------------------------------- procedure Expand_Non_Function_Return (N : Node_Id) is pragma Assert (No (Expression (N))); Loc : constant Source_Ptr := Sloc (N); Scope_Id : Entity_Id := Return_Applies_To (Return_Statement_Entity (N)); Kind : constant Entity_Kind := Ekind (Scope_Id); Call : Node_Id; Acc_Stat : Node_Id; Goto_Stat : Node_Id; Lab_Node : Node_Id; begin -- Call _Postconditions procedure if procedure with active -- postconditions. Here, we use the Postcondition_Proc attribute, -- which is needed for implicitly-generated returns. Functions -- never have implicitly-generated returns, and there's no -- room for Postcondition_Proc in E_Function, so we look up the -- identifier Name_uPostconditions for function returns (see -- Expand_Simple_Function_Return). if Ekind (Scope_Id) = E_Procedure and then Has_Postconditions (Scope_Id) then pragma Assert (Present (Postcondition_Proc (Scope_Id))); Insert_Action (N, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (Postcondition_Proc (Scope_Id), Loc))); end if; -- If it is a return from a procedure do no extra steps if Kind = E_Procedure or else Kind = E_Generic_Procedure then return; -- If it is a nested return within an extended one, replace it with a -- return of the previously declared return object. elsif Kind = E_Return_Statement then Rewrite (N, Make_Simple_Return_Statement (Loc, Expression => New_Occurrence_Of (First_Entity (Scope_Id), Loc))); Set_Comes_From_Extended_Return_Statement (N); Set_Return_Statement_Entity (N, Scope_Id); Expand_Simple_Function_Return (N); return; end if; pragma Assert (Is_Entry (Scope_Id)); -- Look at the enclosing block to see whether the return is from an -- accept statement or an entry body. for J in reverse 0 .. Scope_Stack.Last loop Scope_Id := Scope_Stack.Table (J).Entity; exit when Is_Concurrent_Type (Scope_Id); end loop; -- If it is a return from accept statement it is expanded as call to -- RTS Complete_Rendezvous and a goto to the end of the accept body. -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept, -- Expand_N_Accept_Alternative in exp_ch9.adb) if Is_Task_Type (Scope_Id) then Call := Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Complete_Rendezvous), Loc)); Insert_Before (N, Call); -- why not insert actions here??? Analyze (Call); Acc_Stat := Parent (N); while Nkind (Acc_Stat) /= N_Accept_Statement loop Acc_Stat := Parent (Acc_Stat); end loop; Lab_Node := Last (Statements (Handled_Statement_Sequence (Acc_Stat))); Goto_Stat := Make_Goto_Statement (Loc, Name => New_Occurrence_Of (Entity (Identifier (Lab_Node)), Loc)); Set_Analyzed (Goto_Stat); Rewrite (N, Goto_Stat); Analyze (N); -- If it is a return from an entry body, put a Complete_Entry_Body call -- in front of the return. elsif Is_Protected_Type (Scope_Id) then Call := Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Complete_Entry_Body), Loc), Parameter_Associations => New_List ( Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Find_Protection_Object (Current_Scope), Loc), Attribute_Name => Name_Unchecked_Access))); Insert_Before (N, Call); Analyze (Call); end if; end Expand_Non_Function_Return; --------------------------------------- -- Expand_Protected_Object_Reference -- --------------------------------------- function Expand_Protected_Object_Reference (N : Node_Id; Scop : Entity_Id) return Node_Id is Loc : constant Source_Ptr := Sloc (N); Corr : Entity_Id; Rec : Node_Id; Param : Entity_Id; Proc : Entity_Id; begin Rec := Make_Identifier (Loc, Name_uObject); Set_Etype (Rec, Corresponding_Record_Type (Scop)); -- Find enclosing protected operation, and retrieve its first parameter, -- which denotes the enclosing protected object. If the enclosing -- operation is an entry, we are immediately within the protected body, -- and we can retrieve the object from the service entries procedure. A -- barrier function has the same signature as an entry. A barrier -- function is compiled within the protected object, but unlike -- protected operations its never needs locks, so that its protected -- body subprogram points to itself. Proc := Current_Scope; while Present (Proc) and then Scope (Proc) /= Scop loop Proc := Scope (Proc); end loop; Corr := Protected_Body_Subprogram (Proc); if No (Corr) then -- Previous error left expansion incomplete. -- Nothing to do on this call. return Empty; end if; Param := Defining_Identifier (First (Parameter_Specifications (Parent (Corr)))); if Is_Subprogram (Proc) and then Proc /= Corr then -- Protected function or procedure Set_Entity (Rec, Param); -- Rec is a reference to an entity which will not be in scope when -- the call is reanalyzed, and needs no further analysis. Set_Analyzed (Rec); else -- Entry or barrier function for entry body. The first parameter of -- the entry body procedure is pointer to the object. We create a -- local variable of the proper type, duplicating what is done to -- define _object later on. declare Decls : List_Id; Obj_Ptr : constant Entity_Id := Make_Temporary (Loc, 'T'); begin Decls := New_List ( Make_Full_Type_Declaration (Loc, Defining_Identifier => Obj_Ptr, Type_Definition => Make_Access_To_Object_Definition (Loc, Subtype_Indication => New_Reference_To (Corresponding_Record_Type (Scop), Loc)))); Insert_Actions (N, Decls); Freeze_Before (N, Obj_Ptr); Rec := Make_Explicit_Dereference (Loc, Prefix => Unchecked_Convert_To (Obj_Ptr, New_Occurrence_Of (Param, Loc))); -- Analyze new actual. Other actuals in calls are already analyzed -- and the list of actuals is not reanalyzed after rewriting. Set_Parent (Rec, N); Analyze (Rec); end; end if; return Rec; end Expand_Protected_Object_Reference; -------------------------------------- -- Expand_Protected_Subprogram_Call -- -------------------------------------- procedure Expand_Protected_Subprogram_Call (N : Node_Id; Subp : Entity_Id; Scop : Entity_Id) is Rec : Node_Id; begin -- If the protected object is not an enclosing scope, this is an inter- -- object function call. Inter-object procedure calls are expanded by -- Exp_Ch9.Build_Simple_Entry_Call. The call is intra-object only if the -- subprogram being called is in the protected body being compiled, and -- if the protected object in the call is statically the enclosing type. -- The object may be an component of some other data structure, in which -- case this must be handled as an inter-object call. if not In_Open_Scopes (Scop) or else not Is_Entity_Name (Name (N)) then if Nkind (Name (N)) = N_Selected_Component then Rec := Prefix (Name (N)); else pragma Assert (Nkind (Name (N)) = N_Indexed_Component); Rec := Prefix (Prefix (Name (N))); end if; Build_Protected_Subprogram_Call (N, Name => New_Occurrence_Of (Subp, Sloc (N)), Rec => Convert_Concurrent (Rec, Etype (Rec)), External => True); else Rec := Expand_Protected_Object_Reference (N, Scop); if No (Rec) then return; end if; Build_Protected_Subprogram_Call (N, Name => Name (N), Rec => Rec, External => False); end if; -- If it is a function call it can appear in elaboration code and -- the called entity must be frozen here. if Ekind (Subp) = E_Function then Freeze_Expression (Name (N)); end if; -- Analyze and resolve the new call. The actuals have already been -- resolved, but expansion of a function call will add extra actuals -- if needed. Analysis of a procedure call already includes resolution. Analyze (N); if Ekind (Subp) = E_Function then Resolve (N, Etype (Subp)); end if; end Expand_Protected_Subprogram_Call; -------------------------------------------- -- Has_Unconstrained_Access_Discriminants -- -------------------------------------------- function Has_Unconstrained_Access_Discriminants (Subtyp : Entity_Id) return Boolean is Discr : Entity_Id; begin if Has_Discriminants (Subtyp) and then not Is_Constrained (Subtyp) then Discr := First_Discriminant (Subtyp); while Present (Discr) loop if Ekind (Etype (Discr)) = E_Anonymous_Access_Type then return True; end if; Next_Discriminant (Discr); end loop; end if; return False; end Has_Unconstrained_Access_Discriminants; ----------------------------------- -- Expand_Simple_Function_Return -- ----------------------------------- -- The "simple" comes from the syntax rule simple_return_statement. The -- semantics are not at all simple! procedure Expand_Simple_Function_Return (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Scope_Id : constant Entity_Id := Return_Applies_To (Return_Statement_Entity (N)); -- The function we are returning from R_Type : constant Entity_Id := Etype (Scope_Id); -- The result type of the function Utyp : constant Entity_Id := Underlying_Type (R_Type); Exp : constant Node_Id := Expression (N); pragma Assert (Present (Exp)); Exptyp : constant Entity_Id := Etype (Exp); -- The type of the expression (not necessarily the same as R_Type) Subtype_Ind : Node_Id; -- If the result type of the function is class-wide and the expression -- has a specific type, then we use the expression's type as the type of -- the return object. In cases where the expression is an aggregate that -- is built in place, this avoids the need for an expensive conversion -- of the return object to the specific type on assignments to the -- individual components. begin if Is_Class_Wide_Type (R_Type) and then not Is_Class_Wide_Type (Etype (Exp)) then Subtype_Ind := New_Occurrence_Of (Etype (Exp), Loc); else Subtype_Ind := New_Occurrence_Of (R_Type, Loc); end if; -- For the case of a simple return that does not come from an extended -- return, in the case of Ada 2005 where we are returning a limited -- type, we rewrite "return <expression>;" to be: -- return _anon_ : <return_subtype> := <expression> -- The expansion produced by Expand_N_Extended_Return_Statement will -- contain simple return statements (for example, a block containing -- simple return of the return object), which brings us back here with -- Comes_From_Extended_Return_Statement set. The reason for the barrier -- checking for a simple return that does not come from an extended -- return is to avoid this infinite recursion. -- The reason for this design is that for Ada 2005 limited returns, we -- need to reify the return object, so we can build it "in place", and -- we need a block statement to hang finalization and tasking stuff. -- ??? In order to avoid disruption, we avoid translating to extended -- return except in the cases where we really need to (Ada 2005 for -- inherently limited). We might prefer to do this translation in all -- cases (except perhaps for the case of Ada 95 inherently limited), -- in order to fully exercise the Expand_N_Extended_Return_Statement -- code. This would also allow us to do the build-in-place optimization -- for efficiency even in cases where it is semantically not required. -- As before, we check the type of the return expression rather than the -- return type of the function, because the latter may be a limited -- class-wide interface type, which is not a limited type, even though -- the type of the expression may be. if not Comes_From_Extended_Return_Statement (N) and then Is_Immutably_Limited_Type (Etype (Expression (N))) and then Ada_Version >= Ada_2005 and then not Debug_Flag_Dot_L then declare Return_Object_Entity : constant Entity_Id := Make_Temporary (Loc, 'R', Exp); Obj_Decl : constant Node_Id := Make_Object_Declaration (Loc, Defining_Identifier => Return_Object_Entity, Object_Definition => Subtype_Ind, Expression => Exp); Ext : constant Node_Id := Make_Extended_Return_Statement (Loc, Return_Object_Declarations => New_List (Obj_Decl)); -- Do not perform this high-level optimization if the result type -- is an interface because the "this" pointer must be displaced. begin Rewrite (N, Ext); Analyze (N); return; end; end if; -- Here we have a simple return statement that is part of the expansion -- of an extended return statement (either written by the user, or -- generated by the above code). -- Always normalize C/Fortran boolean result. This is not always needed, -- but it seems a good idea to minimize the passing around of non- -- normalized values, and in any case this handles the processing of -- barrier functions for protected types, which turn the condition into -- a return statement. if Is_Boolean_Type (Exptyp) and then Nonzero_Is_True (Exptyp) then Adjust_Condition (Exp); Adjust_Result_Type (Exp, Exptyp); end if; -- Do validity check if enabled for returns if Validity_Checks_On and then Validity_Check_Returns then Ensure_Valid (Exp); end if; -- Check the result expression of a scalar function against the subtype -- of the function by inserting a conversion. This conversion must -- eventually be performed for other classes of types, but for now it's -- only done for scalars. -- ??? if Is_Scalar_Type (Exptyp) then Rewrite (Exp, Convert_To (R_Type, Exp)); -- The expression is resolved to ensure that the conversion gets -- expanded to generate a possible constraint check. Analyze_And_Resolve (Exp, R_Type); end if; -- Deal with returning variable length objects and controlled types -- Nothing to do if we are returning by reference, or this is not a -- type that requires special processing (indicated by the fact that -- it requires a cleanup scope for the secondary stack case). if Is_Immutably_Limited_Type (Exptyp) or else Is_Limited_Interface (Exptyp) then null; elsif not Requires_Transient_Scope (R_Type) then -- Mutable records with no variable length components are not -- returned on the sec-stack, so we need to make sure that the -- backend will only copy back the size of the actual value, and not -- the maximum size. We create an actual subtype for this purpose. declare Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exptyp)); Decl : Node_Id; Ent : Entity_Id; begin if Has_Discriminants (Ubt) and then not Is_Constrained (Ubt) and then not Has_Unchecked_Union (Ubt) then Decl := Build_Actual_Subtype (Ubt, Exp); Ent := Defining_Identifier (Decl); Insert_Action (Exp, Decl); Rewrite (Exp, Unchecked_Convert_To (Ent, Exp)); Analyze_And_Resolve (Exp); end if; end; -- Here if secondary stack is used else -- Make sure that no surrounding block will reclaim the secondary -- stack on which we are going to put the result. Not only may this -- introduce secondary stack leaks but worse, if the reclamation is -- done too early, then the result we are returning may get -- clobbered. declare S : Entity_Id; begin S := Current_Scope; while Ekind (S) = E_Block or else Ekind (S) = E_Loop loop Set_Sec_Stack_Needed_For_Return (S, True); S := Enclosing_Dynamic_Scope (S); end loop; end; -- Optimize the case where the result is a function call. In this -- case either the result is already on the secondary stack, or is -- already being returned with the stack pointer depressed and no -- further processing is required except to set the By_Ref flag -- to ensure that gigi does not attempt an extra unnecessary copy. -- (actually not just unnecessary but harmfully wrong in the case -- of a controlled type, where gigi does not know how to do a copy). -- To make up for a gcc 2.8.1 deficiency (???), we perform the copy -- for array types if the constrained status of the target type is -- different from that of the expression. if Requires_Transient_Scope (Exptyp) and then (not Is_Array_Type (Exptyp) or else Is_Constrained (Exptyp) = Is_Constrained (R_Type) or else CW_Or_Has_Controlled_Part (Utyp)) and then Nkind (Exp) = N_Function_Call then Set_By_Ref (N); -- Remove side effects from the expression now so that other parts -- of the expander do not have to reanalyze this node without this -- optimization Rewrite (Exp, Duplicate_Subexpr_No_Checks (Exp)); -- For controlled types, do the allocation on the secondary stack -- manually in order to call adjust at the right time: -- type Anon1 is access R_Type; -- for Anon1'Storage_pool use ss_pool; -- Anon2 : anon1 := new R_Type'(expr); -- return Anon2.all; -- We do the same for classwide types that are not potentially -- controlled (by the virtue of restriction No_Finalization) because -- gigi is not able to properly allocate class-wide types. elsif CW_Or_Has_Controlled_Part (Utyp) then declare Loc : constant Source_Ptr := Sloc (N); Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A'); Alloc_Node : Node_Id; Temp : Entity_Id; begin Set_Ekind (Acc_Typ, E_Access_Type); Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool)); -- This is an allocator for the secondary stack, and it's fine -- to have Comes_From_Source set False on it, as gigi knows not -- to flag it as a violation of No_Implicit_Heap_Allocations. Alloc_Node := Make_Allocator (Loc, Expression => Make_Qualified_Expression (Loc, Subtype_Mark => New_Reference_To (Etype (Exp), Loc), Expression => Relocate_Node (Exp))); -- We do not want discriminant checks on the declaration, -- given that it gets its value from the allocator. Set_No_Initialization (Alloc_Node); Temp := Make_Temporary (Loc, 'R', Alloc_Node); Insert_List_Before_And_Analyze (N, New_List ( Make_Full_Type_Declaration (Loc, Defining_Identifier => Acc_Typ, Type_Definition => Make_Access_To_Object_Definition (Loc, Subtype_Indication => Subtype_Ind)), Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Reference_To (Acc_Typ, Loc), Expression => Alloc_Node))); Rewrite (Exp, Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Temp, Loc))); -- Ada 2005 (AI-251): If the type of the returned object is -- an interface then add an implicit type conversion to force -- displacement of the "this" pointer. if Is_Interface (R_Type) then Rewrite (Exp, Convert_To (R_Type, Relocate_Node (Exp))); end if; Analyze_And_Resolve (Exp, R_Type); end; -- Otherwise use the gigi mechanism to allocate result on the -- secondary stack. else Check_Restriction (No_Secondary_Stack, N); Set_Storage_Pool (N, RTE (RE_SS_Pool)); -- If we are generating code for the VM do not use -- SS_Allocate since everything is heap-allocated anyway. if VM_Target = No_VM then Set_Procedure_To_Call (N, RTE (RE_SS_Allocate)); end if; end if; end if; -- Implement the rules of 6.5(8-10), which require a tag check in -- the case of a limited tagged return type, and tag reassignment for -- nonlimited tagged results. These actions are needed when the return -- type is a specific tagged type and the result expression is a -- conversion or a formal parameter, because in that case the tag of -- the expression might differ from the tag of the specific result type. if Is_Tagged_Type (Utyp) and then not Is_Class_Wide_Type (Utyp) and then (Nkind_In (Exp, N_Type_Conversion, N_Unchecked_Type_Conversion) or else (Is_Entity_Name (Exp) and then Ekind (Entity (Exp)) in Formal_Kind)) then -- When the return type is limited, perform a check that the tag of -- the result is the same as the tag of the return type. if Is_Limited_Type (R_Type) then Insert_Action (Exp, Make_Raise_Constraint_Error (Loc, Condition => Make_Op_Ne (Loc, Left_Opnd => Make_Selected_Component (Loc, Prefix => Duplicate_Subexpr (Exp), Selector_Name => Make_Identifier (Loc, Name_uTag)), Right_Opnd => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Base_Type (Utyp), Loc), Attribute_Name => Name_Tag)), Reason => CE_Tag_Check_Failed)); -- If the result type is a specific nonlimited tagged type, then we -- have to ensure that the tag of the result is that of the result -- type. This is handled by making a copy of the expression in -- the case where it might have a different tag, namely when the -- expression is a conversion or a formal parameter. We create a new -- object of the result type and initialize it from the expression, -- which will implicitly force the tag to be set appropriately. else declare ExpR : constant Node_Id := Relocate_Node (Exp); Result_Id : constant Entity_Id := Make_Temporary (Loc, 'R', ExpR); Result_Exp : constant Node_Id := New_Reference_To (Result_Id, Loc); Result_Obj : constant Node_Id := Make_Object_Declaration (Loc, Defining_Identifier => Result_Id, Object_Definition => New_Reference_To (R_Type, Loc), Constant_Present => True, Expression => ExpR); begin Set_Assignment_OK (Result_Obj); Insert_Action (Exp, Result_Obj); Rewrite (Exp, Result_Exp); Analyze_And_Resolve (Exp, R_Type); end; end if; -- Ada 2005 (AI-344): If the result type is class-wide, then insert -- a check that the level of the return expression's underlying type -- is not deeper than the level of the master enclosing the function. -- Always generate the check when the type of the return expression -- is class-wide, when it's a type conversion, or when it's a formal -- parameter. Otherwise, suppress the check in the case where the -- return expression has a specific type whose level is known not to -- be statically deeper than the function's result type. -- Note: accessibility check is skipped in the VM case, since there -- does not seem to be any practical way to implement this check. elsif Ada_Version >= Ada_2005 and then Tagged_Type_Expansion and then Is_Class_Wide_Type (R_Type) and then not Scope_Suppress (Accessibility_Check) and then (Is_Class_Wide_Type (Etype (Exp)) or else Nkind_In (Exp, N_Type_Conversion, N_Unchecked_Type_Conversion) or else (Is_Entity_Name (Exp) and then Ekind (Entity (Exp)) in Formal_Kind) or else Scope_Depth (Enclosing_Dynamic_Scope (Etype (Exp))) > Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id))) then declare Tag_Node : Node_Id; begin -- Ada 2005 (AI-251): In class-wide interface objects we displace -- "this" to reference the base of the object. This is required to -- get access to the TSD of the object. if Is_Class_Wide_Type (Etype (Exp)) and then Is_Interface (Etype (Exp)) and then Nkind (Exp) = N_Explicit_Dereference then Tag_Node := Make_Explicit_Dereference (Loc, Prefix => Unchecked_Convert_To (RTE (RE_Tag_Ptr), Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Base_Address), Loc), Parameter_Associations => New_List ( Unchecked_Convert_To (RTE (RE_Address), Duplicate_Subexpr (Prefix (Exp))))))); else Tag_Node := Make_Attribute_Reference (Loc, Prefix => Duplicate_Subexpr (Exp), Attribute_Name => Name_Tag); end if; Insert_Action (Exp, Make_Raise_Program_Error (Loc, Condition => Make_Op_Gt (Loc, Left_Opnd => Build_Get_Access_Level (Loc, Tag_Node), Right_Opnd => Make_Integer_Literal (Loc, Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))), Reason => PE_Accessibility_Check_Failed)); end; -- AI05-0073: If function has a controlling access result, check that -- the tag of the return value, if it is not null, matches designated -- type of return type. -- The return expression is referenced twice in the code below, so -- it must be made free of side effects. Given that different compilers -- may evaluate these parameters in different order, both occurrences -- perform a copy. elsif Ekind (R_Type) = E_Anonymous_Access_Type and then Has_Controlling_Result (Scope_Id) then Insert_Action (N, Make_Raise_Constraint_Error (Loc, Condition => Make_And_Then (Loc, Left_Opnd => Make_Op_Ne (Loc, Left_Opnd => Duplicate_Subexpr (Exp), Right_Opnd => Make_Null (Loc)), Right_Opnd => Make_Op_Ne (Loc, Left_Opnd => Make_Selected_Component (Loc, Prefix => Duplicate_Subexpr (Exp), Selector_Name => Make_Identifier (Loc, Name_uTag)), Right_Opnd => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Designated_Type (R_Type), Loc), Attribute_Name => Name_Tag))), Reason => CE_Tag_Check_Failed), Suppress => All_Checks); end if; -- AI05-0234: RM 6.5(21/3). Check access discriminants to -- ensure that the function result does not outlive an -- object designated by one of it discriminants. if Present (Extra_Accessibility_Of_Result (Scope_Id)) and then Has_Unconstrained_Access_Discriminants (R_Type) then declare Discrim_Source : Node_Id; procedure Check_Against_Result_Level (Level : Node_Id); -- Check the given accessibility level against the level -- determined by the point of call. (AI05-0234). -------------------------------- -- Check_Against_Result_Level -- -------------------------------- procedure Check_Against_Result_Level (Level : Node_Id) is begin Insert_Action (N, Make_Raise_Program_Error (Loc, Condition => Make_Op_Gt (Loc, Left_Opnd => Level, Right_Opnd => New_Occurrence_Of (Extra_Accessibility_Of_Result (Scope_Id), Loc)), Reason => PE_Accessibility_Check_Failed)); end Check_Against_Result_Level; begin Discrim_Source := Exp; while Nkind (Discrim_Source) = N_Qualified_Expression loop Discrim_Source := Expression (Discrim_Source); end loop; if Nkind (Discrim_Source) = N_Identifier and then Is_Return_Object (Entity (Discrim_Source)) then Discrim_Source := Entity (Discrim_Source); if Is_Constrained (Etype (Discrim_Source)) then Discrim_Source := Etype (Discrim_Source); else Discrim_Source := Expression (Parent (Discrim_Source)); end if; elsif Nkind (Discrim_Source) = N_Identifier and then Nkind_In (Original_Node (Discrim_Source), N_Aggregate, N_Extension_Aggregate) then Discrim_Source := Original_Node (Discrim_Source); elsif Nkind (Discrim_Source) = N_Explicit_Dereference and then Nkind (Original_Node (Discrim_Source)) = N_Function_Call then Discrim_Source := Original_Node (Discrim_Source); end if; while Nkind_In (Discrim_Source, N_Qualified_Expression, N_Type_Conversion, N_Unchecked_Type_Conversion) loop Discrim_Source := Expression (Discrim_Source); end loop; case Nkind (Discrim_Source) is when N_Defining_Identifier => pragma Assert (Is_Composite_Type (Discrim_Source) and then Has_Discriminants (Discrim_Source) and then Is_Constrained (Discrim_Source)); declare Discrim : Entity_Id := First_Discriminant (Base_Type (R_Type)); Disc_Elmt : Elmt_Id := First_Elmt (Discriminant_Constraint (Discrim_Source)); begin loop if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then Check_Against_Result_Level (Dynamic_Accessibility_Level (Node (Disc_Elmt))); end if; Next_Elmt (Disc_Elmt); Next_Discriminant (Discrim); exit when not Present (Discrim); end loop; end; when N_Aggregate | N_Extension_Aggregate => -- Unimplemented: extension aggregate case where discrims -- come from ancestor part, not extension part. declare Discrim : Entity_Id := First_Discriminant (Base_Type (R_Type)); Disc_Exp : Node_Id := Empty; Positionals_Exhausted : Boolean := not Present (Expressions (Discrim_Source)); function Associated_Expr (Comp_Id : Entity_Id; Associations : List_Id) return Node_Id; -- Given a component and a component associations list, -- locate the expression for that component; returns -- Empty if no such expression is found. --------------------- -- Associated_Expr -- --------------------- function Associated_Expr (Comp_Id : Entity_Id; Associations : List_Id) return Node_Id is Assoc : Node_Id; Choice : Node_Id; begin -- Simple linear search seems ok here Assoc := First (Associations); while Present (Assoc) loop Choice := First (Choices (Assoc)); while Present (Choice) loop if (Nkind (Choice) = N_Identifier and then Chars (Choice) = Chars (Comp_Id)) or else (Nkind (Choice) = N_Others_Choice) then return Expression (Assoc); end if; Next (Choice); end loop; Next (Assoc); end loop; return Empty; end Associated_Expr; -- Start of processing for Expand_Simple_Function_Return begin if not Positionals_Exhausted then Disc_Exp := First (Expressions (Discrim_Source)); end if; loop if Positionals_Exhausted then Disc_Exp := Associated_Expr (Discrim, Component_Associations (Discrim_Source)); end if; if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then Check_Against_Result_Level (Dynamic_Accessibility_Level (Disc_Exp)); end if; Next_Discriminant (Discrim); exit when not Present (Discrim); if not Positionals_Exhausted then Next (Disc_Exp); Positionals_Exhausted := not Present (Disc_Exp); end if; end loop; end; when N_Function_Call => -- No check needed (check performed by callee) null; when others => declare Level : constant Node_Id := Make_Integer_Literal (Loc, Object_Access_Level (Discrim_Source)); begin -- Unimplemented: check for name prefix that includes -- a dereference of an access value with a dynamic -- accessibility level (e.g., an access param or a -- saooaaat) and use dynamic level in that case. For -- example: -- return Access_Param.all(Some_Index).Some_Component; -- ??? Set_Etype (Level, Standard_Natural); Check_Against_Result_Level (Level); end; end case; end; end if; -- If we are returning an object that may not be bit-aligned, then copy -- the value into a temporary first. This copy may need to expand to a -- loop of component operations. if Is_Possibly_Unaligned_Slice (Exp) or else Is_Possibly_Unaligned_Object (Exp) then declare ExpR : constant Node_Id := Relocate_Node (Exp); Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR); begin Insert_Action (Exp, Make_Object_Declaration (Loc, Defining_Identifier => Tnn, Constant_Present => True, Object_Definition => New_Occurrence_Of (R_Type, Loc), Expression => ExpR), Suppress => All_Checks); Rewrite (Exp, New_Occurrence_Of (Tnn, Loc)); end; end if; -- Generate call to postcondition checks if they are present if Ekind (Scope_Id) = E_Function and then Has_Postconditions (Scope_Id) then -- We are going to reference the returned value twice in this case, -- once in the call to _Postconditions, and once in the actual return -- statement, but we can't have side effects happening twice, and in -- any case for efficiency we don't want to do the computation twice. -- If the returned expression is an entity name, we don't need to -- worry since it is efficient and safe to reference it twice, that's -- also true for literals other than string literals, and for the -- case of X.all where X is an entity name. if Is_Entity_Name (Exp) or else Nkind_In (Exp, N_Character_Literal, N_Integer_Literal, N_Real_Literal) or else (Nkind (Exp) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (Exp))) then null; -- Otherwise we are going to need a temporary to capture the value else declare ExpR : constant Node_Id := Relocate_Node (Exp); Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR); begin -- For a complex expression of an elementary type, capture -- value in the temporary and use it as the reference. if Is_Elementary_Type (R_Type) then Insert_Action (Exp, Make_Object_Declaration (Loc, Defining_Identifier => Tnn, Constant_Present => True, Object_Definition => New_Occurrence_Of (R_Type, Loc), Expression => ExpR), Suppress => All_Checks); Rewrite (Exp, New_Occurrence_Of (Tnn, Loc)); -- If we have something we can rename, generate a renaming of -- the object and replace the expression with a reference elsif Is_Object_Reference (Exp) then Insert_Action (Exp, Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Tnn, Subtype_Mark => New_Occurrence_Of (R_Type, Loc), Name => ExpR), Suppress => All_Checks); Rewrite (Exp, New_Occurrence_Of (Tnn, Loc)); -- Otherwise we have something like a string literal or an -- aggregate. We could copy the value, but that would be -- inefficient. Instead we make a reference to the value and -- capture this reference with a renaming, the expression is -- then replaced by a dereference of this renaming. else -- For now, copy the value, since the code below does not -- seem to work correctly ??? Insert_Action (Exp, Make_Object_Declaration (Loc, Defining_Identifier => Tnn, Constant_Present => True, Object_Definition => New_Occurrence_Of (R_Type, Loc), Expression => Relocate_Node (Exp)), Suppress => All_Checks); Rewrite (Exp, New_Occurrence_Of (Tnn, Loc)); -- Insert_Action (Exp, -- Make_Object_Renaming_Declaration (Loc, -- Defining_Identifier => Tnn, -- Access_Definition => -- Make_Access_Definition (Loc, -- All_Present => True, -- Subtype_Mark => New_Occurrence_Of (R_Type, Loc)), -- Name => -- Make_Reference (Loc, -- Prefix => Relocate_Node (Exp))), -- Suppress => All_Checks); -- Rewrite (Exp, -- Make_Explicit_Dereference (Loc, -- Prefix => New_Occurrence_Of (Tnn, Loc))); end if; end; end if; -- Generate call to _postconditions Insert_Action (Exp, Make_Procedure_Call_Statement (Loc, Name => Make_Identifier (Loc, Name_uPostconditions), Parameter_Associations => New_List (Duplicate_Subexpr (Exp)))); end if; -- Ada 2005 (AI-251): If this return statement corresponds with an -- simple return statement associated with an extended return statement -- and the type of the returned object is an interface then generate an -- implicit conversion to force displacement of the "this" pointer. if Ada_Version >= Ada_2005 and then Comes_From_Extended_Return_Statement (N) and then Nkind (Expression (N)) = N_Identifier and then Is_Interface (Utyp) and then Utyp /= Underlying_Type (Exptyp) then Rewrite (Exp, Convert_To (Utyp, Relocate_Node (Exp))); Analyze_And_Resolve (Exp); end if; end Expand_Simple_Function_Return; -------------------------------- -- Is_Build_In_Place_Function -- -------------------------------- function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is begin -- This function is called from Expand_Subtype_From_Expr during -- semantic analysis, even when expansion is off. In those cases -- the build_in_place expansion will not take place. if not Expander_Active then return False; end if; -- For now we test whether E denotes a function or access-to-function -- type whose result subtype is inherently limited. Later this test may -- be revised to allow composite nonlimited types. Functions with a -- foreign convention or whose result type has a foreign convention -- never qualify. if Ekind_In (E, E_Function, E_Generic_Function) or else (Ekind (E) = E_Subprogram_Type and then Etype (E) /= Standard_Void_Type) then -- Note: If you have Convention (C) on an inherently limited type, -- you're on your own. That is, the C code will have to be carefully -- written to know about the Ada conventions. if Has_Foreign_Convention (E) or else Has_Foreign_Convention (Etype (E)) then return False; -- In Ada 2005 all functions with an inherently limited return type -- must be handled using a build-in-place profile, including the case -- of a function with a limited interface result, where the function -- may return objects of nonlimited descendants. else return Is_Immutably_Limited_Type (Etype (E)) and then Ada_Version >= Ada_2005 and then not Debug_Flag_Dot_L; end if; else return False; end if; end Is_Build_In_Place_Function; ------------------------------------- -- Is_Build_In_Place_Function_Call -- ------------------------------------- function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is Exp_Node : Node_Id := N; Function_Id : Entity_Id; begin -- Return False when the expander is inactive, since awareness of -- build-in-place treatment is only relevant during expansion. Note that -- Is_Build_In_Place_Function, which is called as part of this function, -- is also conditioned this way, but we need to check here as well to -- avoid blowing up on processing protected calls when expansion is -- disabled (such as with -gnatc) since those would trip over the raise -- of Program_Error below. if not Expander_Active then return False; end if; -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Exp_Node, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Exp_Node := Expression (N); end if; if Nkind (Exp_Node) /= N_Function_Call then return False; else -- In Alfa mode, build-in-place calls are not expanded, so that we -- may end up with a call that is neither resolved to an entity, nor -- an indirect call. if Alfa_Mode then return False; elsif Is_Entity_Name (Name (Exp_Node)) then Function_Id := Entity (Name (Exp_Node)); -- In the case of an explicitly dereferenced call, use the subprogram -- type generated for the dereference. elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then Function_Id := Etype (Name (Exp_Node)); else raise Program_Error; end if; return Is_Build_In_Place_Function (Function_Id); end if; end Is_Build_In_Place_Function_Call; ----------------------- -- Freeze_Subprogram -- ----------------------- procedure Freeze_Subprogram (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); procedure Register_Predefined_DT_Entry (Prim : Entity_Id); -- (Ada 2005): Register a predefined primitive in all the secondary -- dispatch tables of its primitive type. ---------------------------------- -- Register_Predefined_DT_Entry -- ---------------------------------- procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is Iface_DT_Ptr : Elmt_Id; Tagged_Typ : Entity_Id; Thunk_Id : Entity_Id; Thunk_Code : Node_Id; begin Tagged_Typ := Find_Dispatching_Type (Prim); if No (Access_Disp_Table (Tagged_Typ)) or else not Has_Interfaces (Tagged_Typ) or else not RTE_Available (RE_Interface_Tag) or else Restriction_Active (No_Dispatching_Calls) then return; end if; -- Skip the first two access-to-dispatch-table pointers since they -- leads to the primary dispatch table (predefined DT and user -- defined DT). We are only concerned with the secondary dispatch -- table pointers. Note that the access-to- dispatch-table pointer -- corresponds to the first implemented interface retrieved below. Iface_DT_Ptr := Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ)))); while Present (Iface_DT_Ptr) and then Ekind (Node (Iface_DT_Ptr)) = E_Constant loop pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code); if Present (Thunk_Code) then Insert_Actions_After (N, New_List ( Thunk_Code, Build_Set_Predefined_Prim_Op_Address (Loc, Tag_Node => New_Reference_To (Node (Next_Elmt (Iface_DT_Ptr)), Loc), Position => DT_Position (Prim), Address_Node => Unchecked_Convert_To (RTE (RE_Prim_Ptr), Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Thunk_Id, Loc), Attribute_Name => Name_Unrestricted_Access))), Build_Set_Predefined_Prim_Op_Address (Loc, Tag_Node => New_Reference_To (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))), Loc), Position => DT_Position (Prim), Address_Node => Unchecked_Convert_To (RTE (RE_Prim_Ptr), Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Prim, Loc), Attribute_Name => Name_Unrestricted_Access))))); end if; -- Skip the tag of the predefined primitives dispatch table Next_Elmt (Iface_DT_Ptr); pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); -- Skip tag of the no-thunks dispatch table Next_Elmt (Iface_DT_Ptr); pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); -- Skip tag of predefined primitives no-thunks dispatch table Next_Elmt (Iface_DT_Ptr); pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); Next_Elmt (Iface_DT_Ptr); end loop; end Register_Predefined_DT_Entry; -- Local variables Subp : constant Entity_Id := Entity (N); -- Start of processing for Freeze_Subprogram begin -- We suppress the initialization of the dispatch table entry when -- VM_Target because the dispatching mechanism is handled internally -- by the VM. if Is_Dispatching_Operation (Subp) and then not Is_Abstract_Subprogram (Subp) and then Present (DTC_Entity (Subp)) and then Present (Scope (DTC_Entity (Subp))) and then Tagged_Type_Expansion and then not Restriction_Active (No_Dispatching_Calls) and then RTE_Available (RE_Tag) then declare Typ : constant Entity_Id := Scope (DTC_Entity (Subp)); begin -- Handle private overridden primitives if not Is_CPP_Class (Typ) then Check_Overriding_Operation (Subp); end if; -- We assume that imported CPP primitives correspond with objects -- whose constructor is in the CPP side; therefore we don't need -- to generate code to register them in the dispatch table. if Is_CPP_Class (Typ) then null; -- Handle CPP primitives found in derivations of CPP_Class types. -- These primitives must have been inherited from some parent, and -- there is no need to register them in the dispatch table because -- Build_Inherit_Prims takes care of the initialization of these -- slots. elsif Is_Imported (Subp) and then (Convention (Subp) = Convention_CPP or else Convention (Subp) = Convention_C) then null; -- Generate code to register the primitive in non statically -- allocated dispatch tables elsif not Building_Static_DT (Scope (DTC_Entity (Subp))) then -- When a primitive is frozen, enter its name in its dispatch -- table slot. if not Is_Interface (Typ) or else Present (Interface_Alias (Subp)) then if Is_Predefined_Dispatching_Operation (Subp) then Register_Predefined_DT_Entry (Subp); end if; Insert_Actions_After (N, Register_Primitive (Loc, Prim => Subp)); end if; end if; end; end if; -- Mark functions that return by reference. Note that it cannot be part -- of the normal semantic analysis of the spec since the underlying -- returned type may not be known yet (for private types). declare Typ : constant Entity_Id := Etype (Subp); Utyp : constant Entity_Id := Underlying_Type (Typ); begin if Is_Immutably_Limited_Type (Typ) then Set_Returns_By_Ref (Subp); elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then Set_Returns_By_Ref (Subp); end if; end; end Freeze_Subprogram; ----------------------- -- Is_Null_Procedure -- ----------------------- function Is_Null_Procedure (Subp : Entity_Id) return Boolean is Decl : constant Node_Id := Unit_Declaration_Node (Subp); begin if Ekind (Subp) /= E_Procedure then return False; -- Check if this is a declared null procedure elsif Nkind (Decl) = N_Subprogram_Declaration then if not Null_Present (Specification (Decl)) then return False; elsif No (Body_To_Inline (Decl)) then return False; -- Check if the body contains only a null statement, followed by -- the return statement added during expansion. else declare Orig_Bod : constant Node_Id := Body_To_Inline (Decl); Stat : Node_Id; Stat2 : Node_Id; begin if Nkind (Orig_Bod) /= N_Subprogram_Body then return False; else -- We must skip SCIL nodes because they are currently -- implemented as special N_Null_Statement nodes. Stat := First_Non_SCIL_Node (Statements (Handled_Statement_Sequence (Orig_Bod))); Stat2 := Next_Non_SCIL_Node (Stat); return Is_Empty_List (Declarations (Orig_Bod)) and then Nkind (Stat) = N_Null_Statement and then (No (Stat2) or else (Nkind (Stat2) = N_Simple_Return_Statement and then No (Next (Stat2)))); end if; end; end if; else return False; end if; end Is_Null_Procedure; ------------------------------------------- -- Make_Build_In_Place_Call_In_Allocator -- ------------------------------------------- procedure Make_Build_In_Place_Call_In_Allocator (Allocator : Node_Id; Function_Call : Node_Id) is Acc_Type : constant Entity_Id := Etype (Allocator); Loc : Source_Ptr; Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Result_Subt : Entity_Id; New_Allocator : Node_Id; Return_Obj_Access : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an allocator context, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Available_View (Etype (Function_Id)); -- Check whether return type includes tasks. This may not have been done -- previously, if the type was a limited view. if Has_Task (Result_Subt) then Build_Activation_Chain_Entity (Allocator); end if; -- When the result subtype is constrained, the return object must be -- allocated on the caller side, and access to it is passed to the -- function. -- Here and in related routines, we must examine the full view of the -- type, because the view at the point of call may differ from that -- that in the function body, and the expansion mechanism depends on -- the characteristics of the full view. if Is_Constrained (Underlying_Type (Result_Subt)) then -- Replace the initialized allocator of form "new T'(Func (...))" -- with an uninitialized allocator of form "new T", where T is the -- result subtype of the called function. The call to the function -- is handled separately further below. New_Allocator := Make_Allocator (Loc, Expression => New_Reference_To (Result_Subt, Loc)); Set_No_Initialization (New_Allocator); -- Copy attributes to new allocator. Note that the new allocator -- logically comes from source if the original one did, so copy the -- relevant flag. This ensures proper treatment of the restriction -- No_Implicit_Heap_Allocations in this case. Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator)); Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator)); Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator)); Rewrite (Allocator, New_Allocator); -- Create a new access object and initialize it to the result of the -- new uninitialized allocator. Note: we do not use Allocator as the -- Related_Node of Return_Obj_Access in call to Make_Temporary below -- as this would create a sort of infinite "recursion". Return_Obj_Access := Make_Temporary (Loc, 'R'); Set_Etype (Return_Obj_Access, Acc_Type); Insert_Action (Allocator, Make_Object_Declaration (Loc, Defining_Identifier => Return_Obj_Access, Object_Definition => New_Reference_To (Acc_Type, Loc), Expression => Relocate_Node (Allocator))); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); -- Add an implicit actual to the function call that provides access -- to the allocated object. An unchecked conversion to the (specific) -- result subtype of the function is inserted to handle cases where -- the access type of the allocator has a class-wide designated type. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Return_Obj_Access, Loc)))); -- When the result subtype is unconstrained, the function itself must -- perform the allocation of the return object, so we pass parameters -- indicating that. We don't yet handle the case where the allocation -- must be done in a user-defined storage pool, which will require -- passing another actual or two to provide allocation/deallocation -- operations. ??? else -- Case of a user-defined storage pool. Pass an allocation parameter -- indicating that the function should allocate its result in the -- pool, and pass the pool. Use 'Unrestricted_Access because the -- pool may not be aliased. if VM_Target = No_VM and then Present (Associated_Storage_Pool (Acc_Type)) then Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => User_Storage_Pool, Pool_Actual => Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Associated_Storage_Pool (Acc_Type), Loc), Attribute_Name => Name_Unrestricted_Access)); -- No user-defined pool; pass an allocation parameter indicating that -- the function should allocate its result on the heap. else Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Global_Heap); end if; Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); -- The caller does not provide the return object in this case, so we -- have to pass null for the object access actual. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Return_Object => Empty); end if; -- If the build-in-place function call returns a controlled object, -- the finalization master will require a reference to routine -- Finalize_Address of the designated type. Setting this attribute -- is done in the same manner to expansion of allocators. if Needs_Finalization (Result_Subt) then -- Controlled types with supressed finalization do not need to -- associate the address of their Finalize_Address primitives with -- a master since they do not need a master to begin with. if Is_Library_Level_Entity (Acc_Type) and then Finalize_Storage_Only (Result_Subt) then null; -- Do not generate the call to Set_Finalize_Address in Alfa mode -- because it is not necessary and results in unwanted expansion. -- This expansion is also not carried out in CodePeer mode because -- Finalize_Address is never built. elsif not Alfa_Mode and then not CodePeer_Mode then Insert_Action (Allocator, Make_Set_Finalize_Address_Call (Loc, Typ => Etype (Function_Id), Ptr_Typ => Acc_Type)); end if; end if; -- Finally, replace the allocator node with a reference to the result -- of the function call itself (which will effectively be an access -- to the object created by the allocator). Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call))); -- Ada 2005 (AI-251): If the type of the allocator is an interface then -- generate an implicit conversion to force displacement of the "this" -- pointer. if Is_Interface (Designated_Type (Acc_Type)) then Rewrite (Allocator, Convert_To (Acc_Type, Relocate_Node (Allocator))); end if; Analyze_And_Resolve (Allocator, Acc_Type); end Make_Build_In_Place_Call_In_Allocator; --------------------------------------------------- -- Make_Build_In_Place_Call_In_Anonymous_Context -- --------------------------------------------------- procedure Make_Build_In_Place_Call_In_Anonymous_Context (Function_Call : Node_Id) is Loc : Source_Ptr; Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Result_Subt : Entity_Id; Return_Obj_Id : Entity_Id; Return_Obj_Decl : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. One place this can occur is for calls to build-in-place -- functions that occur within a call to a protected operation, where -- due to rewriting and expansion of the protected call there can be -- more than one call to Expand_Actuals for the same set of actuals. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Function_Id); -- If the build-in-place function returns a controlled object, then the -- object needs to be finalized immediately after the context. Since -- this case produces a transient scope, the servicing finalizer needs -- to name the returned object. Create a temporary which is initialized -- with the function call: -- -- Temp_Id : Func_Type := BIP_Func_Call; -- -- The initialization expression of the temporary will be rewritten by -- the expander using the appropriate mechanism in Make_Build_In_Place_ -- Call_In_Object_Declaration. if Needs_Finalization (Result_Subt) then declare Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'R'); Temp_Decl : Node_Id; begin -- Reset the guard on the function call since the following does -- not perform actual call expansion. Set_Is_Expanded_Build_In_Place_Call (Func_Call, False); Temp_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp_Id, Object_Definition => New_Reference_To (Result_Subt, Loc), Expression => New_Copy_Tree (Function_Call)); Insert_Action (Function_Call, Temp_Decl); Rewrite (Function_Call, New_Reference_To (Temp_Id, Loc)); Analyze (Function_Call); end; -- When the result subtype is constrained, an object of the subtype is -- declared and an access value designating it is passed as an actual. elsif Is_Constrained (Underlying_Type (Result_Subt)) then -- Create a temporary object to hold the function result Return_Obj_Id := Make_Temporary (Loc, 'R'); Set_Etype (Return_Obj_Id, Result_Subt); Return_Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Return_Obj_Id, Aliased_Present => True, Object_Definition => New_Reference_To (Result_Subt, Loc)); Set_No_Initialization (Return_Obj_Decl); Insert_Action (Func_Call, Return_Obj_Decl); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call, Function_Id); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); -- Add an implicit actual to the function call that provides access -- to the caller's return object. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc)); -- When the result subtype is unconstrained, the function must allocate -- the return object in the secondary stack, so appropriate implicit -- parameters are added to the call to indicate that. A transient -- scope is established to ensure eventual cleanup of the result. else -- Pass an allocation parameter indicating that the function should -- allocate its result on the secondary stack. Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call, Function_Id); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); -- Pass a null value to the function since no return object is -- available on the caller side. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Empty); end if; end Make_Build_In_Place_Call_In_Anonymous_Context; -------------------------------------------- -- Make_Build_In_Place_Call_In_Assignment -- -------------------------------------------- procedure Make_Build_In_Place_Call_In_Assignment (Assign : Node_Id; Function_Call : Node_Id) is Lhs : constant Node_Id := Name (Assign); Func_Call : Node_Id := Function_Call; Func_Id : Entity_Id; Loc : Source_Ptr; Obj_Decl : Node_Id; Obj_Id : Entity_Id; Ptr_Typ : Entity_Id; Ptr_Typ_Decl : Node_Id; New_Expr : Node_Id; Result_Subt : Entity_Id; Target : Node_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an assignment context, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Func_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Func_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Func_Id); -- When the result subtype is unconstrained, an additional actual must -- be passed to indicate that the caller is providing the return object. -- This parameter must also be passed when the called function has a -- controlling result, because dispatching calls to the function needs -- to be treated effectively the same as calls to class-wide functions. Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Func_Id, Alloc_Form => Caller_Allocation); Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call, Func_Id); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster)); -- Add an implicit actual to the function call that provides access to -- the caller's return object. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Func_Id, Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => Relocate_Node (Lhs))); -- Create an access type designating the function's result subtype Ptr_Typ := Make_Temporary (Loc, 'A'); Ptr_Typ_Decl := Make_Full_Type_Declaration (Loc, Defining_Identifier => Ptr_Typ, Type_Definition => Make_Access_To_Object_Definition (Loc, All_Present => True, Subtype_Indication => New_Reference_To (Result_Subt, Loc))); Insert_After_And_Analyze (Assign, Ptr_Typ_Decl); -- Finally, create an access object initialized to a reference to the -- function call. We know this access value is non-null, so mark the -- entity accordingly to suppress junk access checks. New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call)); Obj_Id := Make_Temporary (Loc, 'R', New_Expr); Set_Etype (Obj_Id, Ptr_Typ); Set_Is_Known_Non_Null (Obj_Id); Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Obj_Id, Object_Definition => New_Reference_To (Ptr_Typ, Loc), Expression => New_Expr); Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl); Rewrite (Assign, Make_Null_Statement (Loc)); -- Retrieve the target of the assignment if Nkind (Lhs) = N_Selected_Component then Target := Selector_Name (Lhs); elsif Nkind (Lhs) = N_Type_Conversion then Target := Expression (Lhs); else Target := Lhs; end if; -- If we are assigning to a return object or this is an expression of -- an extension aggregate, the target should either be an identifier -- or a simple expression. All other cases imply a different scenario. if Nkind (Target) in N_Has_Entity then Target := Entity (Target); else return; end if; end Make_Build_In_Place_Call_In_Assignment; ---------------------------------------------------- -- Make_Build_In_Place_Call_In_Object_Declaration -- ---------------------------------------------------- procedure Make_Build_In_Place_Call_In_Object_Declaration (Object_Decl : Node_Id; Function_Call : Node_Id) is Loc : Source_Ptr; Obj_Def_Id : constant Entity_Id := Defining_Identifier (Object_Decl); Enclosing_Func : constant Entity_Id := Enclosing_Subprogram (Obj_Def_Id); Call_Deref : Node_Id; Caller_Object : Node_Id; Def_Id : Entity_Id; Fmaster_Actual : Node_Id := Empty; Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Pool_Actual : Node_Id; Ptr_Typ_Decl : Node_Id; Pass_Caller_Acc : Boolean := False; New_Expr : Node_Id; Ref_Type : Entity_Id; Result_Subt : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an object declaration, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Function_Id); -- If the the object is a return object of an enclosing build-in-place -- function, then the implicit build-in-place parameters of the -- enclosing function are simply passed along to the called function. -- (Unfortunately, this won't cover the case of extension aggregates -- where the ancestor part is a build-in-place unconstrained function -- call that should be passed along the caller's parameters. Currently -- those get mishandled by reassigning the result of the call to the -- aggregate return object, when the call result should really be -- directly built in place in the aggregate and not in a temporary. ???) if Is_Return_Object (Defining_Identifier (Object_Decl)) then Pass_Caller_Acc := True; -- When the enclosing function has a BIP_Alloc_Form formal then we -- pass it along to the callee (such as when the enclosing function -- has an unconstrained or tagged result type). if Needs_BIP_Alloc_Form (Enclosing_Func) then if VM_Target = No_VM and then RTE_Available (RE_Root_Storage_Pool_Ptr) then Pool_Actual := New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Storage_Pool), Loc); -- The build-in-place pool formal is not built on .NET/JVM else Pool_Actual := Empty; end if; Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form_Exp => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form), Loc), Pool_Actual => Pool_Actual); -- Otherwise, if enclosing function has a constrained result subtype, -- then caller allocation will be used. else Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); end if; if Needs_BIP_Finalization_Master (Enclosing_Func) then Fmaster_Actual := New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Finalization_Master), Loc); end if; -- Retrieve the BIPacc formal from the enclosing function and convert -- it to the access type of the callee's BIP_Object_Access formal. Caller_Object := Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Etype (Build_In_Place_Formal (Function_Id, BIP_Object_Access)), Loc), Expression => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access), Loc)); -- In the constrained case, add an implicit actual to the function call -- that provides access to the declared object. An unchecked conversion -- to the (specific) result type of the function is inserted to handle -- the case where the object is declared with a class-wide type. elsif Is_Constrained (Underlying_Type (Result_Subt)) then Caller_Object := Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => New_Reference_To (Obj_Def_Id, Loc)); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); -- In other unconstrained cases, pass an indication to do the allocation -- on the secondary stack and set Caller_Object to Empty so that a null -- value will be passed for the caller's object address. A transient -- scope is established to ensure eventual cleanup of the result. else Add_Unconstrained_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); Caller_Object := Empty; Establish_Transient_Scope (Object_Decl, Sec_Stack => True); end if; -- Pass along any finalization master actual, which is needed in the -- case where the called function initializes a return object of an -- enclosing build-in-place function. Add_Finalization_Master_Actual_To_Build_In_Place_Call (Func_Call => Func_Call, Func_Id => Function_Id, Master_Exp => Fmaster_Actual); if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement and then Has_Task (Result_Subt) then -- Here we're passing along the master that was passed in to this -- function. Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Task_Master), Loc)); else Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); end if; Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc); -- Create an access type designating the function's result subtype. We -- use the type of the original expression because it may be a call to -- an inherited operation, which the expansion has replaced with the -- parent operation that yields the parent type. Ref_Type := Make_Temporary (Loc, 'A'); Ptr_Typ_Decl := Make_Full_Type_Declaration (Loc, Defining_Identifier => Ref_Type, Type_Definition => Make_Access_To_Object_Definition (Loc, All_Present => True, Subtype_Indication => New_Reference_To (Etype (Function_Call), Loc))); -- The access type and its accompanying object must be inserted after -- the object declaration in the constrained case, so that the function -- call can be passed access to the object. In the unconstrained case, -- or if the object declaration is for a return object, the access type -- and object must be inserted before the object, since the object -- declaration is rewritten to be a renaming of a dereference of the -- access object. if Is_Constrained (Underlying_Type (Result_Subt)) and then not Is_Return_Object (Defining_Identifier (Object_Decl)) then Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl); else Insert_Action (Object_Decl, Ptr_Typ_Decl); end if; -- Finally, create an access object initialized to a reference to the -- function call. We know this access value cannot be null, so mark the -- entity accordingly to suppress the access check. New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call)); Def_Id := Make_Temporary (Loc, 'R', New_Expr); Set_Etype (Def_Id, Ref_Type); Set_Is_Known_Non_Null (Def_Id); Insert_After_And_Analyze (Ptr_Typ_Decl, Make_Object_Declaration (Loc, Defining_Identifier => Def_Id, Object_Definition => New_Reference_To (Ref_Type, Loc), Expression => New_Expr)); -- If the result subtype of the called function is constrained and -- is not itself the return expression of an enclosing BIP function, -- then mark the object as having no initialization. if Is_Constrained (Underlying_Type (Result_Subt)) and then not Is_Return_Object (Defining_Identifier (Object_Decl)) then Set_Expression (Object_Decl, Empty); Set_No_Initialization (Object_Decl); -- In case of an unconstrained result subtype, or if the call is the -- return expression of an enclosing BIP function, rewrite the object -- declaration as an object renaming where the renamed object is a -- dereference of <function_Call>'reference: -- -- Obj : Subt renames <function_call>'Ref.all; else Call_Deref := Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Def_Id, Loc)); Loc := Sloc (Object_Decl); Rewrite (Object_Decl, Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Make_Temporary (Loc, 'D'), Access_Definition => Empty, Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), Name => Call_Deref)); Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref); Analyze (Object_Decl); -- Replace the internal identifier of the renaming declaration's -- entity with identifier of the original object entity. We also have -- to exchange the entities containing their defining identifiers to -- ensure the correct replacement of the object declaration by the -- object renaming declaration to avoid homograph conflicts (since -- the object declaration's defining identifier was already entered -- in current scope). The Next_Entity links of the two entities also -- have to be swapped since the entities are part of the return -- scope's entity list and the list structure would otherwise be -- corrupted. Finally, the homonym chain must be preserved as well. declare Renaming_Def_Id : constant Entity_Id := Defining_Identifier (Object_Decl); Next_Entity_Temp : constant Entity_Id := Next_Entity (Renaming_Def_Id); begin Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id)); -- Swap next entity links in preparation for exchanging entities Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id)); Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp); Set_Homonym (Renaming_Def_Id, Homonym (Obj_Def_Id)); Exchange_Entities (Renaming_Def_Id, Obj_Def_Id); -- Preserve source indication of original declaration, so that -- xref information is properly generated for the right entity. Preserve_Comes_From_Source (Object_Decl, Original_Node (Object_Decl)); Preserve_Comes_From_Source (Obj_Def_Id, Original_Node (Object_Decl)); Set_Comes_From_Source (Renaming_Def_Id, False); end; end if; -- If the object entity has a class-wide Etype, then we need to change -- it to the result subtype of the function call, because otherwise the -- object will be class-wide without an explicit initialization and -- won't be allocated properly by the back end. It seems unclean to make -- such a revision to the type at this point, and we should try to -- improve this treatment when build-in-place functions with class-wide -- results are implemented. ??? if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then Set_Etype (Defining_Identifier (Object_Decl), Result_Subt); end if; end Make_Build_In_Place_Call_In_Object_Declaration; ----------------------------------- -- Needs_BIP_Finalization_Master -- ----------------------------------- function Needs_BIP_Finalization_Master (Func_Id : Entity_Id) return Boolean is pragma Assert (Is_Build_In_Place_Function (Func_Id)); Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); begin return not Restriction_Active (No_Finalization) and then Needs_Finalization (Func_Typ); end Needs_BIP_Finalization_Master; -------------------------- -- Needs_BIP_Alloc_Form -- -------------------------- function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean is pragma Assert (Is_Build_In_Place_Function (Func_Id)); Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); begin return not Is_Constrained (Func_Typ) or else Is_Tagged_Type (Func_Typ); end Needs_BIP_Alloc_Form; -------------------------------------- -- Needs_Result_Accessibility_Level -- -------------------------------------- function Needs_Result_Accessibility_Level (Func_Id : Entity_Id) return Boolean is Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); function Has_Unconstrained_Access_Discriminant_Component (Comp_Typ : Entity_Id) return Boolean; -- Returns True if any component of the type has an unconstrained access -- discriminant. ----------------------------------------------------- -- Has_Unconstrained_Access_Discriminant_Component -- ----------------------------------------------------- function Has_Unconstrained_Access_Discriminant_Component (Comp_Typ : Entity_Id) return Boolean is begin if not Is_Limited_Type (Comp_Typ) then return False; -- Only limited types can have access discriminants with -- defaults. elsif Has_Unconstrained_Access_Discriminants (Comp_Typ) then return True; elsif Is_Array_Type (Comp_Typ) then return Has_Unconstrained_Access_Discriminant_Component (Underlying_Type (Component_Type (Comp_Typ))); elsif Is_Record_Type (Comp_Typ) then declare Comp : Entity_Id; begin Comp := First_Component (Comp_Typ); while Present (Comp) loop if Has_Unconstrained_Access_Discriminant_Component (Underlying_Type (Etype (Comp))) then return True; end if; Next_Component (Comp); end loop; end; end if; return False; end Has_Unconstrained_Access_Discriminant_Component; Feature_Disabled : constant Boolean := True; -- Temporary -- Start of processing for Needs_Result_Accessibility_Level begin -- False if completion unavailable (how does this happen???) if not Present (Func_Typ) then return False; elsif Feature_Disabled then return False; -- False if not a function, also handle enum-lit renames case elsif Func_Typ = Standard_Void_Type or else Is_Scalar_Type (Func_Typ) then return False; -- Handle a corner case, a cross-dialect subp renaming. For example, -- an Ada 2012 renaming of an Ada 2005 subprogram. This can occur when -- an Ada 2005 (or earlier) unit references predefined run-time units. elsif Present (Alias (Func_Id)) then -- Unimplemented: a cross-dialect subp renaming which does not set -- the Alias attribute (e.g., a rename of a dereference of an access -- to subprogram value). ??? return Present (Extra_Accessibility_Of_Result (Alias (Func_Id))); -- Remaining cases require Ada 2012 mode elsif Ada_Version < Ada_2012 then return False; elsif Ekind (Func_Typ) = E_Anonymous_Access_Type or else Is_Tagged_Type (Func_Typ) then -- In the case of, say, a null tagged record result type, the need -- for this extra parameter might not be obvious. This function -- returns True for all tagged types for compatibility reasons. -- A function with, say, a tagged null controlling result type might -- be overridden by a primitive of an extension having an access -- discriminant and the overrider and overridden must have compatible -- calling conventions (including implicitly declared parameters). -- Similarly, values of one access-to-subprogram type might designate -- both a primitive subprogram of a given type and a function -- which is, for example, not a primitive subprogram of any type. -- Again, this requires calling convention compatibility. -- It might be possible to solve these issues by introducing -- wrappers, but that is not the approach that was chosen. return True; elsif Has_Unconstrained_Access_Discriminants (Func_Typ) then return True; elsif Has_Unconstrained_Access_Discriminant_Component (Func_Typ) then return True; -- False for all other cases else return False; end if; end Needs_Result_Accessibility_Level; end Exp_Ch6;