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8sa1-gcc/gcc/ada/exp_ch6.adb
Joseph Myers 44d6a70684 5ataprop.adb, [...]: Fix spelling errors. 
* 5ataprop.adb, 5atpopsp.adb, 5ftaprop.adb, 5gmastop.adb,
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	7sintman.adb, 7staprop.adb, 9drpc.adb, ChangeLog, Makefile.in,
	a-except.adb, a-tags.ads, a-tasatt.adb, a-teioed.adb,
	a-textio.ads, a-witeio.ads, a-wtedit.adb, ali.ads, comperr.adb,
	cstand.adb, einfo.ads, errout.adb, exp_ch11.adb, exp_ch2.adb,
	exp_ch3.adb, exp_ch4.adb, exp_ch5.adb, exp_ch6.adb, exp_ch9.adb,
	exp_util.adb, exp_util.ads, fname-uf.adb, g-cgi.ads, g-exctra.ads,
	g-expect.ads, g-regist.adb, g-spipat.adb, gnatchop.adb,
	gnatlink.adb, gnatls.adb, gnatmain.adb, gnatmem.adb, init.c,
	make.adb, make.ads, mdlltool.adb, nlists.ads, osint.ads,
	par-ch3.adb, par-ch4.adb, par-ch5.adb, par-ch6.adb, par.adb,
	repinfo.adb, s-fatflt.ads, s-fatlfl.ads, s-fatllf.ads,
	s-fatsfl.ads, s-finimp.adb, s-finimp.ads, s-interr.adb,
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	s-tarest.ads, s-tasdeb.adb, s-tassta.adb, s-tassta.ads,
	s-vaflop.ads, scans.ads, scn.adb, sem.ads, sem_aggr.adb,
	sem_attr.adb, sem_case.ads, sem_ch10.adb, sem_ch12.adb,
	sem_ch13.adb, sem_ch3.adb, sem_ch3.ads, sem_ch5.adb, sem_ch7.adb,
	sem_ch8.adb, sem_ch8.ads, sem_type.adb, sem_util.ads, sinfo.ads,
	sprint.adb, tbuild.ads, types.ads, utils.c, xeinfo.adb: Fix
	spelling errors.

From-SVN: r48055
2001-12-16 01:13:56 +00:00

3260 lines
115 KiB
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- E X P _ C H 6 --
-- --
-- B o d y --
-- --
-- $Revision: 1.3 $
-- --
-- Copyright (C) 1992-2001, 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 2, 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 COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
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_Ch2; use Exp_Ch2;
with Exp_Ch3; use Exp_Ch3;
with Exp_Ch7; use Exp_Ch7;
with Exp_Ch9; use Exp_Ch9;
with Exp_Ch11; use Exp_Ch11;
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 Freeze; use Freeze;
with Hostparm; use Hostparm;
with Inline; use Inline;
with Lib; use Lib;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Restrict; use Restrict;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
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_Disp; use Sem_Disp;
with Sem_Dist; use Sem_Dist;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Snames; use Snames;
with Stand; use Stand;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Validsw; use Validsw;
package body Exp_Ch6 is
-----------------------
-- Local Subprograms --
-----------------------
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_Actuals (N : Node_Id; Subp : Entity_Id);
-- For each actual of an in-out parameter which is a numeric conversion
-- of the form T(A), where A denotes a variable, we insert the declaration:
--
-- Temp : T := T(A);
--
-- prior to the call. Then we replace the actual with a reference to Temp,
-- and append the assignment:
--
-- A := T' (Temp);
--
-- after the call. Here T' is the actual type of variable A.
-- For out parameters, the initial declaration has no expression.
-- If A is not an entity name, we generate instead:
--
-- Var : T' renames A;
-- Temp : T := Var; -- omitting expression for out parameter.
-- ...
-- Var := T' (Temp);
--
-- For other in-out parameters, we emit the required constraint checks
-- before and/or after the call.
-- For all parameter modes, actuals that denote components and slices
-- of packed arrays are expanded into suitable temporaries.
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).
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.
--------------------------------
-- 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 Typ = 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 : Elist_Id := New_Elmt_List;
-- List of globals referenced by body of procedure
Call_List : Elist_Id := New_Elmt_List;
-- List of recursive calls in body of procedure
Shad_List : 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 Is_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;
-- 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 Restrictions (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.
New_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_Defining_Identifier (Loc,
Chars => New_Internal_Name ('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)),
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 In and In-Out parameters, 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. This
-- routine also takes care of any constraint checks required for the
-- type conversion case (on both the way in and the way out).
procedure Add_Packed_Call_By_Copy_Code;
-- This is used when the actual involves a reference to an element
-- of a packed array, where we can appropriately use a simpler
-- approach than the full call by copy code. We just copy the value
-- in and out of an appropriate 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 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;
Var : Entity_Id;
V_Typ : Entity_Id;
Crep : Boolean;
begin
Temp := Make_Defining_Identifier (Loc, New_Internal_Name ('T'));
if Nkind (Actual) = N_Type_Conversion then
V_Typ := Etype (Expression (Actual));
Var := Make_Var (Expression (Actual));
Crep := not Same_Representation
(Etype (Formal), 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 Ekind (Formal) = E_In_Out_Parameter
or else (Is_Array_Type (Etype (Formal))
and then
not Is_Constrained (Etype (Formal)))
then
if Nkind (Actual) = N_Type_Conversion then
if Conversion_OK (Actual) then
Init := OK_Convert_To
(Etype (Formal), New_Occurrence_Of (Var, Loc));
else
Init := Convert_To
(Etype (Formal), New_Occurrence_Of (Var, Loc));
end if;
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 (Etype (Formal))
or else
Is_Bit_Packed_Array (Etype (Expression (Actual))))
then
if Conversion_OK (Actual) then
Init :=
OK_Convert_To (Etype (Formal), New_Occurrence_Of (Var, Loc));
else
Init :=
Convert_To (Etype (Formal), New_Occurrence_Of (Var, Loc));
end if;
else
Init := Empty;
end if;
N_Node :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition =>
New_Occurrence_Of (Etype (Formal), Loc),
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;
-- 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);
Append_To (Post_Call,
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Var, Loc),
Expression => Expr));
Set_Assignment_OK (Name (Last (Post_Call)));
end Add_Call_By_Copy_Code;
----------------------------------
-- Add_Packed_Call_By_Copy_Code --
----------------------------------
procedure Add_Packed_Call_By_Copy_Code is
Temp : Entity_Id;
Incod : Node_Id;
Outcod : Node_Id;
Lhs : Node_Id;
Rhs : Node_Id;
begin
Reset_Packed_Prefix;
-- Prepare to generate code
Temp := Make_Defining_Identifier (Loc, New_Internal_Name ('T'));
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 variable.
if Ekind (Formal) = E_Out_Parameter then
Incod := Empty;
end if;
Insert_Action (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition =>
New_Occurrence_Of (Etype (Formal), Loc),
Expression => Incod));
-- 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));
end if;
end Add_Packed_Call_By_Copy_Code;
---------------------------
-- Check_Fortran_Logical --
---------------------------
procedure Check_Fortran_Logical is
Logical : 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;
--------------
-- 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_Defining_Identifier (Loc, New_Internal_Name ('T'));
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 Nkind (Pfx) /= N_Selected_Component
and then Nkind (Pfx) /= N_Indexed_Component;
Pfx := Prefix (Pfx);
end loop;
end Reset_Packed_Prefix;
-- Start of processing for Expand_Actuals
begin
Formal := First_Formal (Subp);
Actual := First_Actual (N);
Post_Call := New_List;
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;
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_Packed_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;
-- Deal with access types where the actual subtpe and the
-- formal subtype are not the same, requiring a check.
-- It is necessary to exclude tagged types because of "downward
-- conversion" errors and a strange assertion error in namet
-- from gnatf in bug 1215-001 ???
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;
elsif Is_Entity_Name (Actual)
and then Is_Volatile (Entity (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;
end if;
-- The only processing required for IN parameters is in the packed
-- array case, where we expand the 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.
-- Similarly, we have to expand slices of packed arrays here
else
if Nkind (Actual) = N_Indexed_Component
and then Is_Packed (Etype (Prefix (Actual)))
then
Reset_Packed_Prefix;
Expand_Packed_Element_Reference (Actual);
elsif Is_Ref_To_Bit_Packed_Array (Actual) then
Add_Packed_Call_By_Copy_Code;
elsif Is_Ref_To_Bit_Packed_Slice (Actual) then
declare
Typ : constant Entity_Id := Etype (Actual);
Ent : constant Entity_Id :=
Make_Defining_Identifier (Loc,
Chars => New_Internal_Name ('T'));
Decl : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => Ent,
Object_Definition =>
New_Occurrence_Of (Typ, Loc));
begin
Set_No_Initialization (Decl);
Insert_Actions (N, New_List (
Decl,
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Ent, Loc),
Expression => Relocate_Node (Actual))));
Rewrite
(Actual, New_Occurrence_Of (Ent, Loc));
Analyze_And_Resolve (Actual, Typ);
end;
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
-- If call is not a list member, it must be 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.
if not Is_List_Member (N) then
declare
P : constant Node_Id := Parent (N);
begin
pragma Assert (Nkind (P) = N_Triggering_Alternative
or else Nkind (P) = 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;
-- 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);
Remote : constant Boolean := Is_Remote_Call (N);
Subp : Entity_Id;
Orig_Subp : Entity_Id := Empty;
Parent_Subp : Entity_Id;
Parent_Formal : Entity_Id;
Actual : Node_Id;
Formal : Entity_Id;
Prev : Node_Id := Empty;
Prev_Orig : Node_Id;
Scop : Entity_Id;
Extra_Actuals : List_Id := No_List;
Cond : Node_Id;
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. This is
-- tested in 4723-003. 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.
--------------------------
-- 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 (N));
Set_First_Named_Actual (N, Actual_Expr);
if No (Prev) then
if not Present (Parameter_Associations (N)) then
Set_Parameter_Associations (N, New_List);
Append (Insert_Param, Parameter_Associations (N));
end if;
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 (N));
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, N);
end if;
Append_To (Extra_Actuals,
Make_Parameter_Association (Loc,
Explicit_Actual_Parameter => Expr,
Selector_Name =>
Make_Identifier (Loc, Chars (EF))));
Analyze_And_Resolve (Expr, Etype (EF));
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
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))
or else not In_Instance
then
return Empty;
else
Gen_Par := Generic_Parent_Type (Parent (Par));
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;
-- Start of processing for Expand_Call
begin
-- Call using access to subprogram with explicit dereference
if Nkind (Name (N)) = N_Explicit_Dereference then
Subp := Etype (Name (N));
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 (N)) = N_Selected_Component then
Subp := Entity (Selector_Name (Name (N)));
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 (N)) = N_Indexed_Component then
Subp := Entity (Selector_Name (Prefix (Name (N))));
Parent_Subp := Empty;
-- Normal case
else
Subp := Entity (Name (N));
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.
if not Restrictions (No_Exception_Handlers)
and then Is_RTE (Subp, RE_Raise_Exception)
then
declare
FA : constant Node_Id := Original_Node (First_Actual (N));
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_Entity (Name (N), Subp);
end if;
end;
end if;
if Ekind (Subp) = E_Entry then
Parent_Subp := Empty;
end if;
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 and collect the
-- corresponding actuals in Extra_Actuals.
Formal := First_Formal (Subp);
Actual := First_Actual (N);
while Present (Formal) loop
Prev := Actual;
Prev_Orig := Original_Node (Prev);
-- 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));
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 := Prev;
begin
-- Test for unchecked conversions as well, which can
-- occur as out parameter actuals on calls to stream
-- procedures.
if Nkind (Act_Prev) = N_Type_Conversion
or else Nkind (Act_Prev) = N_Unchecked_Type_Conversion
then
Act_Prev := Expression (Act_Prev);
end if;
Add_Extra_Actual (
Make_Attribute_Reference (Sloc (Prev),
Prefix => Duplicate_Subexpr (Act_Prev, Name_Req => True),
Attribute_Name => Name_Constrained),
Extra_Constrained (Formal));
end;
end if;
end if;
-- Create possible extra actual for accessibility level
if Present (Extra_Accessibility (Formal)) then
if Is_Entity_Name (Prev_Orig) then
-- When passing an access parameter as the actual to another
-- access parameter we need to pass along the actual's own
-- associated access level parameter. This is done is we are
-- in the scope of the formal access parameter (if this is an
-- inlined body the extra formal is irrelevant).
if Ekind (Entity (Prev_Orig)) in Formal_Kind
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 (
Make_Integer_Literal (Loc,
Intval => Type_Access_Level (Etype (Prev_Orig))),
Extra_Accessibility (Formal));
end if;
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 =>
Add_Extra_Actual (
Make_Integer_Literal (Loc,
Intval =>
Object_Access_Level (Prefix (Prev_Orig))),
Extra_Accessibility (Formal));
-- 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,
Scope_Depth (Current_Scope) + 1),
Extra_Accessibility (Formal));
-- For other cases we simply pass the level of the
-- actual's access type.
when others =>
Add_Extra_Actual (
Make_Integer_Literal (Loc,
Intval => Type_Access_Level (Etype (Prev_Orig))),
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 Ekind (Etype (Formal)) /= E_Anonymous_Access_Type
or else Suppress_Accessibility_Checks (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 (Prev) = N_Allocator
or else Nkind (Prev) = N_Attribute_Reference
then
null;
-- Suppress null checks when passing to access parameters
-- of Java subprograms. (Should this be done for other
-- foreign conventions as well ???)
elsif Convention (Subp) = Convention_Java then
null;
else
Cond :=
Make_Op_Eq (Loc,
Left_Opnd => Duplicate_Subexpr (Prev),
Right_Opnd => Make_Null (Loc));
Insert_Action (Prev, Make_Raise_Constraint_Error (Loc, Cond));
end if;
-- Perform appropriate validity checks on parameters
if Validity_Checks_On then
if Ekind (Formal) = E_In_Parameter
and then Validity_Check_In_Params
then
Ensure_Valid (Actual);
elsif Ekind (Formal) = E_In_Out_Parameter
and then Validity_Check_In_Out_Params
then
Ensure_Valid (Actual);
end if;
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 (N)
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;
-- 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_Implicit_If_Statement (N,
Condition =>
Make_Op_Not (Loc,
Get_Remotely_Callable (Duplicate_Subexpr (Actual))),
Then_Statements => New_List (
Make_Procedure_Call_Statement (Loc,
New_Occurrence_Of (RTE
(RE_Raise_Program_Error_For_E_4_18), Loc)))));
end if;
Next_Actual (Actual);
Next_Formal (Formal);
end loop;
-- If we are expanding a rhs of an assignement we need to check if
-- tag propagation is needed. This code belongs theorically in Analyze
-- Assignment but has to be done earlier (bottom-up) because the
-- assignment might be transformed into a declaration for an uncons-
-- trained value, if the expression is classwide.
if Nkind (N) = N_Function_Call
and then Is_Tag_Indeterminate (N)
and then Is_Entity_Name (Name (N))
then
declare
Ass : Node_Id := Empty;
begin
if Nkind (Parent (N)) = N_Assignment_Statement then
Ass := Parent (N);
elsif Nkind (Parent (N)) = N_Qualified_Expression
and then Nkind (Parent (Parent (N))) = N_Assignment_Statement
then
Ass := Parent (Parent (N));
end if;
if Present (Ass)
and then Is_Class_Wide_Type (Etype (Name (Ass)))
then
Propagate_Tag (Name (Ass), N);
return;
end if;
end;
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 Java_VM, because
-- the JVM back end directly handles the generation of dispatching
-- calls and would have to undo any expansion to an indirect call.
if (Nkind (N) = N_Function_Call
or else Nkind (N) = N_Procedure_Call_Statement)
and then Present (Controlling_Argument (N))
and then not Java_VM
then
Expand_Dispatch_Call (N);
return;
-- 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 rewritting to occur in expanded code.
elsif Is_All_Remote_Call (N) then
Expand_All_Calls_Remote_Subprogram_Call (N);
-- 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;
if Ekind (Subp) = E_Procedure
or else (Ekind (Subp) = E_Subprogram_Type
and then Etype (Subp) = Standard_Void_Type)
or else Is_Entry (Subp)
then
Expand_Actuals (N, Subp);
end if;
-- 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 (N) /= N_Entry_Call_Statement
and then No (Controlling_Argument (N))
and then Present (Parent_Subp)
then
if Present (Inherited_From_Formal (Subp)) then
Parent_Subp := Inherited_From_Formal (Subp);
else
while Present (Alias (Parent_Subp)) loop
Parent_Subp := Alias (Parent_Subp);
end loop;
end if;
Set_Entity (Name (N), Parent_Subp);
if Is_Abstract (Parent_Subp)
and then not In_Instance
then
Error_Msg_NE
("cannot call abstract subprogram &!", Name (N), Parent_Subp);
end if;
-- Add an explicit conversion for parameter of the derived type.
-- This is only done for scalar and access in-parameters. Others
-- have been expanded in expand_actuals.
Formal := First_Formal (Subp);
Parent_Formal := First_Formal (Parent_Subp);
Actual := First_Actual (N);
-- It is not clear that conversion is needed for intrinsic
-- subprograms, but it certainly is for those that are user-
-- defined, and that can be inherited on derivation, namely
-- unchecked conversion and deallocation.
-- General case needs study ???
if not Is_Intrinsic_Subprogram (Parent_Subp)
or else Is_Generic_Instance (Parent_Subp)
then
while Present (Formal) loop
if Etype (Formal) /= Etype (Parent_Formal)
and then Is_Scalar_Type (Etype (Formal))
and then Ekind (Formal) = E_In_Parameter
then
Rewrite (Actual,
OK_Convert_To (Etype (Parent_Formal),
Relocate_Node (Actual)));
Analyze (Actual);
Resolve (Actual, Etype (Parent_Formal));
Enable_Range_Check (Actual);
elsif Is_Access_Type (Etype (Formal))
and then Base_Type (Etype (Parent_Formal))
/= Base_Type (Etype (Actual))
then
if Ekind (Formal) /= E_In_Parameter then
Rewrite (Actual,
Convert_To (Etype (Parent_Formal),
Relocate_Node (Actual)));
Analyze (Actual);
Resolve (Actual, Etype (Parent_Formal));
elsif
Ekind (Etype (Parent_Formal)) = E_Anonymous_Access_Type
and then
Designated_Type (Etype (Parent_Formal))
/= Designated_Type (Etype (Actual))
and then not Is_Controlling_Formal (Formal)
then
-- This unchecked conversion is not necessary unless
-- inlining is unabled, because in that case the type
-- mismatch may become visible in the body about to be
-- inlined.
Rewrite (Actual,
Unchecked_Convert_To (Etype (Parent_Formal),
Relocate_Node (Actual)));
Analyze (Actual);
Resolve (Actual, Etype (Parent_Formal));
end if;
end if;
Next_Formal (Formal);
Next_Formal (Parent_Formal);
Next_Actual (Actual);
end loop;
end if;
Orig_Subp := Subp;
Subp := Parent_Subp;
end if;
-- Some more special cases for cases other than explicit dereference
if Nkind (Name (N)) /= N_Explicit_Dereference then
-- Calls to an enumeration literal are replaced by the literal
-- This case occurs only when we have a call to a function that
-- is a renaming of an enumeration literal. The normal case of
-- a direct reference to an enumeration literal has already been
-- been dealt with by Resolve_Call. If the function is itself
-- inherited (see 7423-001) the literal of the parent type must
-- be explicitly converted to the return type of the function.
if Ekind (Subp) = E_Enumeration_Literal then
if Base_Type (Etype (Subp)) /= Base_Type (Etype (N)) then
Rewrite
(N, Convert_To (Etype (N), New_Occurrence_Of (Subp, Loc)));
else
Rewrite (N, New_Occurrence_Of (Subp, Loc));
Resolve (N, Etype (N));
end if;
end if;
-- Handle case of access to protected subprogram type
else
if Ekind (Base_Type (Etype (Prefix (Name (N))))) =
E_Access_Protected_Subprogram_Type
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
-- first parameter of the list of actuals.
declare
Call : Node_Id;
Parm : List_Id;
Nam : Node_Id;
Obj : Node_Id;
Ptr : Node_Id := Prefix (Name (N));
T : Entity_Id := Equivalent_Type (Base_Type (Etype (Ptr)));
D_T : 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, Nam);
if Present (Parameter_Associations (N)) then
Parm := Parameter_Associations (N);
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 (N));
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 (N, 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!)
if Is_Intrinsic_Subprogram (Subp) then
Expand_Intrinsic_Call (N, Subp);
return;
end if;
if Ekind (Subp) = E_Function
or else Ekind (Subp) = E_Procedure
then
if Is_Inlined (Subp) then
declare
Spec : constant Node_Id := Unit_Declaration_Node (Subp);
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 gigi.
if Present (Spec)
and then Nkind (Spec) = N_Subprogram_Declaration
and then Present (Body_To_Inline (Spec))
and then (In_Extended_Main_Code_Unit (N)
or else In_Extended_Main_Code_Unit (Parent (N)))
and then (not In_Same_Extended_Unit
(Sloc (Body_To_Inline (Spec)), Loc)
or else
Earlier_In_Extended_Unit
(Sloc (Body_To_Inline (Spec)), Loc))
then
Expand_Inlined_Call (N, 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 (N))
and then No (Body_To_Inline (Spec))
and then not Has_Completion (Subp)
and then In_Same_Extended_Unit (Sloc (Spec), Loc)
and then Ineffective_Inline_Warnings
then
Error_Msg_N
("call cannot be inlined before body is seen?", N);
end if;
end if;
end;
end if;
end if;
-- Check for a 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.
Scop := Scope (Subp);
if Nkind (N) /= N_Entry_Call_Statement
and then Is_Protected_Type (Scop)
then
-- If the call is an internal one, it is rewritten as a call to
-- to the corresponding unprotected subprogram.
Expand_Protected_Subprogram_Call (N, Subp, Scop);
end if;
-- Functions returning controlled objects need special attention
if Controlled_Type (Etype (Subp))
and then not Is_Return_By_Reference_Type (Etype (Subp))
then
Expand_Ctrl_Function_Call (N);
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
-- retained. 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 (N);
while Formal /= First_Optional_Parameter (Subp) loop
Last_Keep_Arg := Actual;
Next_Formal (Formal);
Next_Actual (Actual);
end loop;
-- Now 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
while Is_Non_Empty_List (Parameter_Associations (N)) loop
Delete_Tree (Remove_Head (Parameter_Associations (N)));
end loop;
Set_Parameter_Associations (N, No_List);
Set_First_Named_Actual (N, 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
Delete_Tree (Remove_Next (Last_Keep_Arg));
end loop;
Set_First_Named_Actual (N, 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;
Junk : 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 (N));
-- Case of all parameters named, remove them all
if Nkind (Temp) = N_Parameter_Association then
while Is_Non_Empty_List (Parameter_Associations (N)) loop
Temp := Remove_Head (Parameter_Associations (N));
end loop;
-- 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
Junk := 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 (N));
loop
Temp := Relocate_Node (Passoc);
Append_To
(Parameter_Associations (N), 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)));
Delete_Tree (Temp);
end loop;
end;
end if;
end;
end if;
end Expand_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);
Blk : Node_Id;
Bod : Node_Id;
Decl : Node_Id;
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;
Orig_Bod : constant Node_Id :=
Body_To_Inline (Unit_Declaration_Node (Subp));
Ret_Type : Entity_Id;
Targ : Node_Id;
Temp : Entity_Id;
Temp_Typ : Entity_Id;
procedure Make_Exit_Label;
-- Build declaration for exit label to be used in Return statements.
function Process_Formals (N : Node_Id) return Traverse_Result;
-- Replace occurrence of a formal with the corresponding actual, or
-- the thunk generated for it.
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.
---------------------
-- Make_Exit_Label --
---------------------
procedure Make_Exit_Label is
begin
-- Create exit label for subprogram, if one doesn't exist yet.
if No (Exit_Lab) then
Lab_Id := Make_Identifier (Loc, New_Internal_Name ('L'));
Set_Entity (Lab_Id,
Make_Defining_Identifier (Loc, Chars (Lab_Id)));
Exit_Lab := Make_Label (Loc, Lab_Id);
Lab_Decl :=
Make_Implicit_Label_Declaration (Loc,
Defining_Identifier => Entity (Lab_Id),
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);
if Is_Entity_Name (A) then
Rewrite (N, New_Occurrence_Of (Entity (A), Loc));
elsif Nkind (A) = N_Defining_Identifier then
Rewrite (N, New_Occurrence_Of (A, Loc));
else -- numeric literal
Rewrite (N, New_Copy (A));
end if;
end if;
return Skip;
elsif Nkind (N) = N_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, eg. 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 (Expression (N)) = N_Aggregate 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;
else
return OK;
end if;
end Process_Formals;
procedure Replace_Formals is new Traverse_Proc (Process_Formals);
---------------------------
-- Rewrite_Function_Call --
---------------------------
procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is
HSS : Node_Id := Handled_Statement_Sequence (Blk);
Fst : 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);
elsif Nkind (Parent (N)) = N_Assignment_Statement
and then Is_Entity_Name (Name (Parent (N)))
then
-- replace assignment with the block.
Rewrite (Parent (N), Blk);
elsif Nkind (Parent (N)) = N_Object_Declaration then
Set_Expression (Parent (N), Empty);
Insert_After (Parent (N), Blk);
end if;
end Rewrite_Function_Call;
----------------------------
-- Rewrite_Procedure_Call --
----------------------------
procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is
HSS : Node_Id := Handled_Statement_Sequence (Blk);
begin
if 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;
-- Start of processing for Expand_Inlined_Call
begin
if Nkind (Orig_Bod) = N_Defining_Identifier then
-- Subprogram is a renaming_as_body. Calls appearing after the
-- renaming can be replaced with calls to the renamed entity
-- directly, because the subprograms are subtype conformant.
Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc));
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 (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;
-- 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;
F := First_Formal (Subp);
A := First_Actual (N);
-- Create temporaries for the actuals that are expressions, or that
-- are scalars and require copying to preserve semantics.
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 (not Is_Entity_Name (A)
and then Nkind (A) /= N_Integer_Literal
and then Nkind (A) /= N_Real_Literal)
or else Is_Scalar_Type (Etype (A))
then
Temp :=
Make_Defining_Identifier (Loc,
Chars => New_Internal_Name ('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_Out_Parameter
or else not Is_Tagged_Type (Etype (F)))
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 Ekind (F) = E_In_Parameter
and then not Is_Limited_Type (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;
Prepend (Decl, Declarations (Blk));
Set_Renamed_Object (F, Temp);
else
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;
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.
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));
else
-- Replace call with temporary, and create its declaration.
Temp :=
Make_Defining_Identifier (Loc, New_Internal_Name ('C'));
Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition =>
New_Occurrence_Of (Ret_Type, Loc));
Set_No_Initialization (Decl);
Insert_Action (N, Decl);
Rewrite (N, New_Occurrence_Of (Temp, Loc));
Targ := Temp;
end if;
end if;
-- 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 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.
declare
I_Flag : constant Boolean := In_Inlined_Body;
begin
In_Inlined_Body := True;
Analyze (Blk);
In_Inlined_Body := I_Flag;
end;
if Ekind (Subp) = E_Procedure then
Rewrite_Procedure_Call (N, Blk);
else
Rewrite_Function_Call (N, Blk);
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_Function_Call --
----------------------------
procedure Expand_N_Function_Call (N : Node_Id) is
Typ : constant Entity_Id := Etype (N);
function Returned_By_Reference return Boolean;
-- If the return type is returned through the secondary stack. i.e.
-- by reference, we don't want to create a temporary to force stack
-- checking.
function Returned_By_Reference return Boolean is
S : Entity_Id := Current_Scope;
begin
if Is_Return_By_Reference_Type (Typ) then
return True;
elsif Nkind (Parent (N)) /= N_Return_Statement then
return False;
elsif Requires_Transient_Scope (Typ) then
-- Verify that the return type of the enclosing function has
-- the same constrained status as that of the expression.
while Ekind (S) /= E_Function loop
S := Scope (S);
end loop;
return Is_Constrained (Typ) = Is_Constrained (Etype (S));
else
return False;
end if;
end Returned_By_Reference;
-- Start of processing for Expand_N_Function_Call
begin
-- A special check. If stack checking is enabled, and the return type
-- might generate a large temporary, and the call is not the right
-- side of an assignment, then generate an explicit temporary. We do
-- this because otherwise gigi may generate a large temporary on the
-- fly and this can cause trouble with stack checking.
if May_Generate_Large_Temp (Typ)
and then Nkind (Parent (N)) /= N_Assignment_Statement
and then
(Nkind (Parent (N)) /= N_Object_Declaration
or else Expression (Parent (N)) /= N)
and then not Returned_By_Reference
then
-- Note: it might be thought that it would be OK to use a call to
-- Force_Evaluation here, but that's not good enough, because that
-- results in a 'Reference construct that may still need a temporary.
declare
Loc : constant Source_Ptr := Sloc (N);
Temp_Obj : constant Entity_Id := Make_Defining_Identifier (Loc,
New_Internal_Name ('F'));
Temp_Typ : Entity_Id := Typ;
Decl : Node_Id;
A : Node_Id;
F : Entity_Id;
Proc : Entity_Id;
begin
if Is_Tagged_Type (Typ)
and then Present (Controlling_Argument (N))
then
if Nkind (Parent (N)) /= N_Procedure_Call_Statement
and then Nkind (Parent (N)) /= N_Function_Call
then
-- If this is a tag-indeterminate call, the object must
-- be classwide.
if Is_Tag_Indeterminate (N) then
Temp_Typ := Class_Wide_Type (Typ);
end if;
else
-- If this is a dispatching call that is itself the
-- controlling argument of an enclosing call, the nominal
-- subtype of the object that replaces it must be classwide,
-- so that dispatching will take place properly. If it is
-- not a controlling argument, the object is not classwide.
Proc := Entity (Name (Parent (N)));
F := First_Formal (Proc);
A := First_Actual (Parent (N));
while A /= N loop
Next_Formal (F);
Next_Actual (A);
end loop;
if Is_Controlling_Formal (F) then
Temp_Typ := Class_Wide_Type (Typ);
end if;
end if;
end if;
Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp_Obj,
Object_Definition => New_Occurrence_Of (Temp_Typ, Loc),
Constant_Present => True,
Expression => Relocate_Node (N));
Set_Assignment_OK (Decl);
Insert_Actions (N, New_List (Decl));
Rewrite (N, New_Occurrence_Of (Temp_Obj, Loc));
end;
-- Normal case, expand the call
else
Expand_Call (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_Subprogram_Body --
------------------------------
-- Add poll call if ATC polling is enabled
-- 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
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;
Spec_Id : Entity_Id;
Except_H : Node_Id;
Scop : Entity_Id;
Dec : Node_Id;
Next_Op : Node_Id;
L : List_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_S : constant Node_Id := Last (S);
-- Get original node, in case raise has been rewritten
begin
if not Is_Transfer (Last_S) then
Append_To (S, Make_Return_Statement (Sloc (Last_S)));
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 (Handled_Statement_Sequence (N));
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
Generate_Poll_Call (First (L));
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;
-- 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.
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 := First_Formal (Spec_Id);
begin
while Present (F) loop
if Is_RTE (Root_Type (Etype (F)), RE_Address) 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 := First_Formal (Spec_Id);
V : constant Boolean := Validity_Checks_On;
begin
-- We turn off validity checking, since we do not want any
-- check on the initializing value itself (which we know
-- may well be invalid!)
Validity_Checks_On := False;
-- Loop through formals
while Present (F) loop
if Is_Scalar_Type (Etype (F))
and then Ekind (F) = E_Out_Parameter
then
Insert_Before_And_Analyze (First (L),
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (F, Loc),
Expression => Get_Simple_Init_Val (Etype (F), Loc)));
end if;
Next_Formal (F);
end loop;
Validity_Checks_On := V;
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;
Scop := Scope (Spec_Id);
-- 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_Return_By_Reference_Type (Typ) then
Set_Returns_By_Ref (Spec_Id);
elsif Present (Utyp) and then Controlled_Type (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. Note that reanalysis is not necessary in this
-- case since it would require a lot of work and accomplish nothing.
if Ekind (Spec_Id) = E_Procedure
or else Ekind (Spec_Id) = 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);
begin
Set_Handled_Statement_Sequence (N,
Make_Handled_Sequence_Of_Statements (Hloc,
Statements => New_List (Blok, Rais)));
New_Scope (Spec_Id);
Analyze (Blok);
Analyze (Rais);
Pop_Scope;
end;
end if;
-- Add discriminal renamings to protected subprograms.
-- Install new discriminals for expansion of the next
-- subprogram of this protected type, if any.
if Is_List_Member (N)
and then Present (Parent (List_Containing (N)))
and then Nkind (Parent (List_Containing (N))) = N_Protected_Body
then
Add_Discriminal_Declarations
(Declarations (N), Scop, Name_uObject, Loc);
Add_Private_Declarations (Declarations (N), Scop, Name_uObject, Loc);
-- Associate privals and discriminals with the next protected
-- operation body to be expanded. These are used to expand
-- references to private data objects and discriminants,
-- respectively.
Next_Op := Next_Protected_Operation (N);
if Present (Next_Op) then
Dec := Parent (Base_Type (Scop));
Set_Privals (Dec, Next_Op, Loc);
Set_Discriminals (Dec, Next_Op, Loc);
end if;
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;
-- Finally, if we are in Normalize_Scalars mode, then any scalar out
-- parameters must be initialized to the appropriate default value.
if Ekind (Spec_Id) = E_Procedure and then Normalize_Scalars then
declare
Floc : Source_Ptr;
Formal : Entity_Id;
Stm : Node_Id;
begin
Formal := First_Formal (Spec_Id);
while Present (Formal) loop
Floc := Sloc (Formal);
if Ekind (Formal) = E_Out_Parameter
and then Is_Scalar_Type (Etype (Formal))
then
Stm :=
Make_Assignment_Statement (Floc,
Name => New_Occurrence_Of (Formal, Floc),
Expression =>
Get_Simple_Init_Val (Etype (Formal), Floc));
Prepend (Stm, Declarations (N));
Analyze (Stm);
end if;
Next_Formal (Formal);
end loop;
end;
end if;
-- If the subprogram does not have pending instantiations, then we
-- must generate the subprogram descriptor now, since the code for
-- the subprogram is complete, and this is our last chance. However
-- if there are pending instantiations, then the code is not
-- complete, and we will delay the generation.
if Is_Subprogram (Spec_Id)
and then not Delay_Subprogram_Descriptors (Spec_Id)
then
Generate_Subprogram_Descriptor_For_Subprogram (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 --
-------------------------------------
-- The first task to be performed is the construction of default
-- expression functions for in parameters with default values. These
-- are parameterless inlined functions that are used to evaluate
-- default expressions that are more complicated than simple literals
-- or identifiers referencing constants and variables.
-- 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.
procedure Expand_N_Subprogram_Declaration (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Subp : Entity_Id := Defining_Entity (N);
Scop : Entity_Id := Scope (Subp);
Prot_Sub : Entity_Id;
Prot_Bod : Node_Id;
begin
-- Deal with case of protected subprogram
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)) then
Prot_Sub :=
Make_Subprogram_Declaration (Loc,
Specification =>
Build_Protected_Sub_Specification
(N, Scop, Unprotected => True));
-- The protected subprogram is declared outside of the protected
-- body. Given that the body has frozen all entities so far, we
-- freeze the subprogram explicitly. 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_Sub);
New_Scope (Scope (Scop));
Analyze (Prot_Sub);
Set_Protected_Body_Subprogram (Subp,
Defining_Unit_Name (Specification (Prot_Sub)));
Pop_Scope;
end if;
end if;
end Expand_N_Subprogram_Declaration;
---------------------------------------
-- 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
-- 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 a
-- 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 : Entity_Id := Make_Defining_Identifier
(Loc, New_Internal_Name ('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);
Insert_Actions (N, Freeze_Entity (Obj_Ptr, Sloc (N)));
Rec :=
Make_Explicit_Dereference (Loc,
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 renalyzed 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;
Analyze (N);
-- 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;
end Expand_Protected_Subprogram_Call;
-----------------------
-- Freeze_Subprogram --
-----------------------
procedure Freeze_Subprogram (N : Node_Id) is
E : constant Entity_Id := Entity (N);
begin
-- When a primitive is frozen, enter its name in the corresponding
-- dispatch table. If the DTC_Entity field is not set this is an
-- overridden primitive that can be ignored. We suppress the
-- initialization of the dispatch table entry when Java_VM because
-- the dispatching mechanism is handled internally by the JVM.
if Is_Dispatching_Operation (E)
and then not Is_Abstract (E)
and then Present (DTC_Entity (E))
and then not Is_CPP_Class (Scope (DTC_Entity (E)))
and then not Java_VM
then
Check_Overriding_Operation (E);
Insert_After (N, Fill_DT_Entry (Sloc (N), E));
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 (E);
Utyp : constant Entity_Id := Underlying_Type (Typ);
begin
if Is_Return_By_Reference_Type (Typ) then
Set_Returns_By_Ref (E);
elsif Present (Utyp) and then Controlled_Type (Utyp) then
Set_Returns_By_Ref (E);
end if;
end;
end Freeze_Subprogram;
end Exp_Ch6;
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