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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- E X P _ C H 6 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2013, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Atree; use Atree;
with 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 Output; use Output;
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 Sinput; use Sinput;
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
Inlined_Calls : Elist_Id := No_Elist;
Backend_Calls : Elist_Id := No_Elist;
-- List of frontend inlined calls and inline calls passed to the backend
-----------------------
-- 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.
procedure Do_Inline (Subp : Entity_Id; Orig_Subp : Entity_Id);
-- Check and inline the body of Subp. Invoked when compiling with
-- optimizations enabled and Subp has pragma inline or inline always.
-- If the subprogram is a renaming, or if it is inherited, then Subp
-- references the renamed entity and Orig_Subp is the entity of the
-- call node N.
procedure Do_Inline_Always (Subp : Entity_Id; Orig_Subp : Entity_Id);
-- Check and inline the body of Subp. Invoked when compiling without
-- optimizations and Subp has pragma inline always. If the subprogram is
-- a renaming, or if it is inherited, then Subp references the renamed
-- entity and Orig_Subp is the entity of the call node N.
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 In_Unfrozen_Instance (E : Entity_Id) return Boolean;
-- Return true if E comes from an instance that is not yet frozen
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;
----------------
-- Do_Inline --
----------------
procedure Do_Inline (Subp : Entity_Id; Orig_Subp : Entity_Id) is
Spec : constant Node_Id := Unit_Declaration_Node (Subp);
procedure Do_Backend_Inline;
-- Check that the call can be safely passed to the backend. If true
-- then register the enclosing unit of Subp to Inlined_Bodies so that
-- the body of Subp can be retrieved and analyzed by the backend.
procedure Register_Backend_Call (N : Node_Id);
-- Append N to the list Backend_Calls
-----------------------
-- Do_Backend_Inline --
-----------------------
procedure Do_Backend_Inline is
begin
-- No extra test needed for init subprograms since we know they
-- are available to the backend!
if Is_Init_Proc (Subp) then
Add_Inlined_Body (Subp);
Register_Backend_Call (Call_Node);
-- Verify that if the body to inline is located in the current
-- unit the inlining does not occur earlier. This avoids
-- order-of-elaboration problems in the back end.
elsif In_Same_Extended_Unit (Call_Node, Subp)
and then Nkind (Spec) = N_Subprogram_Declaration
and then Earlier_In_Extended_Unit
(Loc, Sloc (Body_To_Inline (Spec)))
then
Error_Msg_NE
("cannot inline& (body not seen yet)??", Call_Node, Subp);
else
declare
Backend_Inline : Boolean := True;
begin
-- 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.
if not (In_Extended_Main_Code_Unit (Call_Node))
and then In_Package_Body
then
Backend_Inline :=
not In_Extended_Main_Source_Unit (Subp);
end if;
if Backend_Inline then
Add_Inlined_Body (Subp);
Register_Backend_Call (Call_Node);
end if;
end;
end if;
end Do_Backend_Inline;
---------------------------
-- Register_Backend_Call --
---------------------------
procedure Register_Backend_Call (N : Node_Id) is
begin
if Backend_Calls = No_Elist then
Backend_Calls := New_Elmt_List;
end if;
Append_Elmt (N, To => Backend_Calls);
end Register_Backend_Call;
-- Start of processing for Do_Inline
begin
-- Verify that the body to inline has already been seen
if No (Spec)
or else Nkind (Spec) /= N_Subprogram_Declaration
or else No (Body_To_Inline (Spec))
then
if Comes_From_Source (Subp)
and then Must_Inline (Subp)
then
Cannot_Inline
("cannot inline& (body not seen yet)?", Call_Node, Subp);
-- Let the back end handle it
else
Do_Backend_Inline;
return;
end if;
-- 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
Cannot_Inline
("cannot inline& (unconstrained array)?", Call_Node, Subp);
else
Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);
end if;
end Do_Inline;
----------------------
-- Do_Inline_Always --
----------------------
procedure Do_Inline_Always (Subp : Entity_Id; Orig_Subp : Entity_Id) is
Spec : constant Node_Id := Unit_Declaration_Node (Subp);
Body_Id : Entity_Id;
begin
if No (Spec)
or else Nkind (Spec) /= N_Subprogram_Declaration
or else No (Body_To_Inline (Spec))
or else Serious_Errors_Detected /= 0
then
return;
end if;
Body_Id := Corresponding_Body (Spec);
-- Verify that the body to inline has already been seen
if No (Body_Id)
or else not Analyzed (Body_Id)
then
Set_Is_Inlined (Subp, False);
if Comes_From_Source (Subp) then
-- Report a warning only if the call is located in the unit of
-- the called subprogram; otherwise it is an error.
if not In_Same_Extended_Unit (Call_Node, Subp) then
Cannot_Inline
("cannot inline& (body not seen yet)?", Call_Node, Subp,
Is_Serious => True);
elsif In_Open_Scopes (Subp) then
-- For backward compatibility we generate the same error
-- or warning of the previous implementation. This will
-- be changed when we definitely incorporate the new
-- support ???
if Front_End_Inlining
and then Optimization_Level = 0
then
Error_Msg_N
("call to recursive subprogram cannot be inlined?p?",
N);
-- Do not emit error compiling runtime packages
elsif Is_Predefined_File_Name
(Unit_File_Name (Get_Source_Unit (Subp)))
then
Error_Msg_N
("call to recursive subprogram cannot be inlined??",
N);
else
Error_Msg_N
("call to recursive subprogram cannot be inlined",
N);
end if;
else
Cannot_Inline
("cannot inline& (body not seen yet)?", Call_Node, Subp);
end if;
end if;
return;
-- 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
Cannot_Inline
("cannot inline& (unconstrained array)?", Call_Node, Subp);
-- If the called subprogram comes from an instance in the same
-- unit, and the instance is not yet frozen, inlining might
-- trigger order-of-elaboration problems.
elsif In_Unfrozen_Instance (Scope (Subp)) then
Cannot_Inline
("cannot inline& (unfrozen instance)?", Call_Node, Subp);
else
Expand_Inlined_Call (Call_Node, Subp, Orig_Subp);
end if;
end Do_Inline_Always;
---------------------------
-- 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;
--------------------------
-- In_Unfrozen_Instance --
--------------------------
function In_Unfrozen_Instance (E : Entity_Id) return Boolean is
S : Entity_Id;
begin
S := E;
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;
-------------------------
-- 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_Symbol (Call_Node);
end if;
-- 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;
-- Handle unchecked conversion of access types generated
-- in thunks (cf. Expand_Interface_Thunk).
elsif Is_Access_Type (Etype (Actual))
and then Nkind (Actual) = N_Unchecked_Type_Conversion
then
Parm_Ent := Entity (Expression (Actual));
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 the 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 (Call_Node) in N_Subprogram_Call
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 (Call_Node) in N_Subprogram_Call
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);
-- Verify that the actuals do not share storage. This check must be done
-- on the caller side rather that inside the subprogram to avoid issues
-- of parameter passing.
if Check_Aliasing_Of_Parameters then
Apply_Parameter_Aliasing_Checks (Call_Node, 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 (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;
-- Handle inlining (old semantics)
if Is_Inlined (Subp) and then not Debug_Flag_Dot_K then
Inlined_Subprogram : declare
Bod : Node_Id;
Must_Inline : Boolean := False;
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 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 (Scope (Subp)) 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;
-- Handle inlining (new semantics)
elsif Is_Inlined (Subp) then
declare
Spec : constant Node_Id := Unit_Declaration_Node (Subp);
begin
if Must_Inline (Subp) then
if In_Extended_Main_Code_Unit (Call_Node)
and then In_Same_Extended_Unit (Sloc (Spec), Loc)
and then not Has_Completion (Subp)
then
Cannot_Inline
("cannot inline& (body not seen yet)?",
Call_Node, Subp);
else
Do_Inline_Always (Subp, Orig_Subp);
end if;
elsif Optimization_Level > 0 then
Do_Inline (Subp, Orig_Subp);
end if;
-- The call may have been inlined or may have been passed to
-- the backend. No further action needed if it was inlined.
if Nkind (N) /= N_Function_Call then
return;
end if;
end;
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);
-- When the temporary function result appears inside a case or an if
-- expression, its lifetime must be extended to match that of the
-- context. If not, the function result would be finalized prematurely
-- and the evaluation of the expression could yield the wrong result.
if Within_Case_Or_If_Expression (N)
and then Nkind (N) = N_Explicit_Dereference
then
Set_Is_Processed_Transient (Entity (Prefix (N)));
end if;
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;
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 : Boolean;
Is_Unc_Decl : Boolean;
-- 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 Reset_Dispatching_Calls (N : Node_Id);
-- In subtree N search for occurrences of dispatching calls that use the
-- Ada 2005 Object.Operation notation and the object is a formal of the
-- inlined subprogram. Reset the entity associated with Operation in all
-- the found occurrences.
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));
if No (Handled_Statement_Sequence (N)) then
Set_Handled_Statement_Sequence (N,
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List));
end if;
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);
------------------------------
-- Reset_Dispatching_Calls --
------------------------------
procedure Reset_Dispatching_Calls (N : Node_Id) is
function Do_Reset (N : Node_Id) return Traverse_Result;
-- Comment required ???
--------------
-- Do_Reset --
--------------
function Do_Reset (N : Node_Id) return Traverse_Result is
begin
if Nkind (N) = N_Procedure_Call_Statement
and then Nkind (Name (N)) = N_Selected_Component
and then Nkind (Prefix (Name (N))) = N_Identifier
and then Is_Formal (Entity (Prefix (Name (N))))
and then Is_Dispatching_Operation
(Entity (Selector_Name (Name (N))))
then
Set_Entity (Selector_Name (Name (N)), Empty);
end if;
return OK;
end Do_Reset;
function Do_Reset_Calls is new Traverse_Func (Do_Reset);
-- Local variables
Dummy : constant Traverse_Result := Do_Reset_Calls (N);
pragma Unreferenced (Dummy);
-- Start of processing for Reset_Dispatching_Calls
begin
null;
end Reset_Dispatching_Calls;
---------------------------
-- 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
-- A call to a function which returns an unconstrained type
-- found in the expression initializing an object-declaration is
-- expanded into a procedure call which must be added after the
-- object declaration.
if Is_Unc_Decl and then Debug_Flag_Dot_K then
Insert_Action_After (Parent (N), Blk);
else
Set_Expression (Parent (N), Empty);
Insert_After (Parent (N), Blk);
end if;
elsif Is_Unc and then not Debug_Flag_Dot_K 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
-- Initializations for old/new semantics
if not Debug_Flag_Dot_K then
Is_Unc := Is_Array_Type (Etype (Subp))
and then not Is_Constrained (Etype (Subp));
Is_Unc_Decl := False;
else
Is_Unc := Returns_Unconstrained_Type (Subp)
and then Optimization_Level > 0;
Is_Unc_Decl := Nkind (Parent (N)) = N_Object_Declaration
and then Is_Unc;
end if;
-- 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;
-- Skip inlining if this is not a true inlining since the attribute
-- Body_To_Inline is also set for renamings (see sinfo.ads)
elsif Nkind (Orig_Bod) in N_Entity then
return;
-- Skip inlining if the function returns an unconstrained type using
-- an extended return statement since this part of the new inlining
-- model which is not yet supported by the current implementation. ???
elsif Is_Unc
and then
Nkind (First (Statements (Handled_Statement_Sequence (Orig_Bod))))
= N_Extended_Return_Statement
and then not Debug_Flag_Dot_K
then
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;
-- Register the call in the list of inlined calls
if Inlined_Calls = No_Elist then
Inlined_Calls := New_Elmt_List;
end if;
Append_Elmt (N, To => Inlined_Calls);
-- 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));
-- Old semantics
if not Debug_Flag_Dot_K then
declare
Bod : Node_Id;
begin
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
declare
First_Decl : Node_Id;
begin
First_Decl := First (Declarations (Blk));
if Nkind (First_Decl) /= N_Object_Declaration then
return;
end if;
if Nkind (Parent (N)) /= N_Assignment_Statement then
Targ1 := Defining_Identifier (First_Decl);
else
Targ1 := Name (Parent (N));
end if;
end;
end if;
end;
-- New semantics
else
declare
Bod : Node_Id;
begin
-- General case
if not Is_Unc then
Bod :=
Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True);
Blk :=
Make_Block_Statement (Loc,
Declarations => Declarations (Bod),
Handled_Statement_Sequence =>
Handled_Statement_Sequence (Bod));
-- Inline a call to a function that returns an unconstrained type.
-- The semantic analyzer checked that frontend-inlined functions
-- returning unconstrained types have no declarations and have
-- a single extended return statement. As part of its processing
-- the function was split in two subprograms: a procedure P and
-- a function F that has a block with a call to procedure P (see
-- Split_Unconstrained_Function).
else
pragma Assert
(Nkind
(First
(Statements (Handled_Statement_Sequence (Orig_Bod))))
= N_Block_Statement);
declare
Blk_Stmt : constant Node_Id :=
First
(Statements
(Handled_Statement_Sequence (Orig_Bod)));
First_Stmt : constant Node_Id :=
First
(Statements
(Handled_Statement_Sequence (Blk_Stmt)));
Second_Stmt : constant Node_Id := Next (First_Stmt);
begin
pragma Assert
(Nkind (First_Stmt) = N_Procedure_Call_Statement
and then Nkind (Second_Stmt) = N_Simple_Return_Statement
and then No (Next (Second_Stmt)));
Bod :=
Copy_Generic_Node
(First
(Statements (Handled_Statement_Sequence (Orig_Bod))),
Empty, Instantiating => True);
Blk := Bod;
-- 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 Nkind (Parent (N)) /= N_Assignment_Statement then
Targ1 := Defining_Identifier (First (Declarations (Blk)));
-- 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.
else
Targ1 := Name (Parent (N));
end if;
end;
end if;
if No (Declarations (Bod)) then
Set_Declarations (Blk, New_List);
end if;
end;
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;
-- Reset Last_Assignment for any parameters of mode out or in out, to
-- prevent spurious warnings about overwriting for assignments to the
-- formal in the inlined code.
if Is_Entity_Name (A) and then Ekind (F) /= E_In_Parameter then
Set_Last_Assignment (Entity (A), Empty);
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));
-- New semantics: In an object declaration avoid an extra copy
-- of the result of a call to an inlined function that returns
-- an unconstrained type
elsif Debug_Flag_Dot_K
and then Nkind (Parent (N)) = N_Object_Declaration
and then Is_Unc
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);
if Is_Unc_Decl then
-- Special management for inlining a call to a function that returns
-- an unconstrained type and initializes an object declaration: we
-- avoid generating undesired extra calls and goto statements.
-- Given:
-- function Func (...) return ...
-- begin
-- declare
-- Result : String (1 .. 4);
-- begin
-- Proc (Result, ...);
-- return Result;
-- end;
-- end F;
-- Result : String := Func (...);
-- Replace this object declaration by:
-- Result : String (1 .. 4);
-- Proc (Result, ...);
Remove_Homonym (Targ);
Decl :=
Make_Object_Declaration
(Loc,
Defining_Identifier => Targ,
Object_Definition =>
New_Copy_Tree (Object_Definition (Parent (Targ1))));
Replace_Formals (Decl);
Rewrite (Parent (N), Decl);
Analyze (Parent (N));
-- Avoid spurious warnings since we know that this declaration is
-- referenced by the procedure call.
Set_Never_Set_In_Source (Targ, False);
-- Remove the local declaration of the extended return stmt from the
-- inlined code
Remove (Parent (Targ1));
-- Update the reference to the result (since we have rewriten the
-- object declaration)
declare
Blk_Call_Stmt : Node_Id;
begin
-- Capture the call to the procedure
Blk_Call_Stmt :=
First (Statements (Handled_Statement_Sequence (Blk)));
pragma Assert
(Nkind (Blk_Call_Stmt) = N_Procedure_Call_Statement);
Remove (First (Parameter_Associations (Blk_Call_Stmt)));
Prepend_To (Parameter_Associations (Blk_Call_Stmt),
New_Reference_To (Targ, Loc));
end;
-- Remove the return statement
pragma Assert
(Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) =
N_Simple_Return_Statement);
Remove (Last (Statements (Handled_Statement_Sequence (Blk))));
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 not Comes_From_Source (Subp) or else Is_Predef then
Reset_Slocs (Blk);
end if;
if Is_Unc_Decl then
-- No action needed since return statement has been already removed!
null;
elsif 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;
-- Search for dispatching calls that use the Object.Operation
-- notation using an Object that is a parameter of the inlined
-- function. We reset the decoration of Operation to force
-- the reanalysis of the inlined dispatching call because
-- the actual object has been inlined.
Reset_Dispatching_Calls (Blk);
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);
if Is_Unc_Decl then
null;
-- 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.
elsif 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_Status_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 :=
Status_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 Nkind (N) = N_Function_Call
and then Vax_Float (Etype (N))
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
Check_Error_Detected;
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.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;
--------------------------------------------
-- Make_CPP_Constructor_Call_In_Allocator --
--------------------------------------------
procedure Make_CPP_Constructor_Call_In_Allocator
(Allocator : Node_Id;
Function_Call : Node_Id)
is
Loc : constant Source_Ptr := Sloc (Function_Call);
Acc_Type : constant Entity_Id := Etype (Allocator);
Function_Id : constant Entity_Id := Entity (Name (Function_Call));
Result_Subt : constant Entity_Id := Available_View (Etype (Function_Id));
New_Allocator : Node_Id;
Return_Obj_Access : Entity_Id;
Tmp_Obj : Node_Id;
begin
pragma Assert (Nkind (Allocator) = N_Allocator
and then Nkind (Function_Call) = N_Function_Call);
pragma Assert (Convention (Function_Id) = Convention_CPP
and then Is_Constructor (Function_Id));
pragma Assert (Is_Constrained (Underlying_Type (Result_Subt)));
-- 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);
-- Generate:
-- Rnnn : constant ptr_T := new (T);
-- Init (Rnn.all,...);
Tmp_Obj :=
Make_Object_Declaration (Loc,
Defining_Identifier => Return_Obj_Access,
Constant_Present => True,
Object_Definition => New_Reference_To (Acc_Type, Loc),
Expression => Relocate_Node (Allocator));
Insert_Action (Allocator, Tmp_Obj);
Insert_List_After_And_Analyze (Tmp_Obj,
Build_Initialization_Call (Loc,
Id_Ref =>
Make_Explicit_Dereference (Loc,
Prefix => New_Reference_To (Return_Obj_Access, Loc)),
Typ => Etype (Function_Id),
Constructor_Ref => Function_Call));
-- 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, New_Reference_To (Return_Obj_Access, Loc));
-- 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_CPP_Constructor_Call_In_Allocator;
-----------------------------------
-- 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;
------------------------
-- List_Inlining_Info --
------------------------
procedure List_Inlining_Info is
Elmt : Elmt_Id;
Nod : Node_Id;
Count : Nat;
begin
if not Debug_Flag_Dot_J then
return;
end if;
-- Generate listing of calls inlined by the frontend
if Present (Inlined_Calls) then
Count := 0;
Elmt := First_Elmt (Inlined_Calls);
while Present (Elmt) loop
Nod := Node (Elmt);
if In_Extended_Main_Code_Unit (Nod) then
Count := Count + 1;
if Count = 1 then
Write_Str ("Listing of frontend inlined calls");
Write_Eol;
end if;
Write_Str (" ");
Write_Int (Count);
Write_Str (":");
Write_Location (Sloc (Nod));
Write_Str (":");
Output.Write_Eol;
end if;
Next_Elmt (Elmt);
end loop;
end if;
-- Generate listing of calls passed to the backend
if Present (Backend_Calls) then
Count := 0;
Elmt := First_Elmt (Backend_Calls);
while Present (Elmt) loop
Nod := Node (Elmt);
if In_Extended_Main_Code_Unit (Nod) then
Count := Count + 1;
if Count = 1 then
Write_Str ("Listing of inlined calls passed to the backend");
Write_Eol;
end if;
Write_Str (" ");
Write_Int (Count);
Write_Str (":");
Write_Location (Sloc (Nod));
Output.Write_Eol;
end if;
Next_Elmt (Elmt);
end loop;
end if;
end List_Inlining_Info;
end Exp_Ch6;