-- --
------------------------------------------------------------------------------
+with Accessibility; use Accessibility;
with Atree; use Atree;
with Aspects; use Aspects;
with Checks; use Checks;
-with Contracts; use Contracts;
with Debug; use Debug;
with Einfo; use Einfo;
with Einfo.Entities; use Einfo.Entities;
package body Exp_Ch6 is
- -- Suffix for BIP formals
+ --------------------------------
+ -- Function return mechanisms --
+ --------------------------------
+
+ -- This is a summary of the various function return mechanisms implemented
+ -- in GNAT for Ada 2005 and later versions of the language. In the below
+ -- table, the first column must be read as an if expression: if the result
+ -- type of the function is limited, then the return mechanism is and ...;
+ -- elsif the result type is indefinite or large definite, then ...; elsif
+ -- ...; else ... The different mechanisms are implemented either in the
+ -- front end, or in the back end, or partly in both ends, depending on the
+ -- result type.
+
+ -- Result type | Return mechanism | Front end | Back end
+ -- --------------------------------------------------------------------
+
+ -- Limited Build In Place All
+
+ -- Indefinite/ Secondary Stack Needs Fin. Others
+ -- Large definite
+
+ -- Needs Fin. Secondary Stack All
+ -- (BERS False)
+
+ -- Needs Fin. Invisible Parameter All All
+ -- (BERS True) (return) (call)
+
+ -- By Reference Invisible Parameter All
+
+ -- Others Primary stack/ All
+ -- Registers
+
+ -- Needs Fin.: type needs finalization [RM 7.6(9.1/2-9.6/2)]
+ -- BERS: Opt.Back_End_Return_Slot setting
+
+ -- The table is valid for all calls except for those dispatching on result;
+ -- the latter calls are considered as returning a class-wide type and thus
+ -- always return on the secondary stack, with the help of a small wrapper
+ -- function (thunk) if the original result type is not itself returned on
+ -- the secondary stack as per the above table.
+
+ -- Suffixes for Build-In-Place extra formals
BIP_Alloc_Suffix : constant String := "BIPalloc";
BIP_Storage_Pool_Suffix : constant String := "BIPstoragepool";
-- the activation Chain. Note: Master_Actual can be Empty, but only if
-- there are no tasks.
- procedure Apply_CW_Accessibility_Check (Exp : Node_Id; Func : Entity_Id);
- -- Ada 2005 (AI95-344): If the result type is class-wide, 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 result type of the
- -- function.
-
function Caller_Known_Size
(Func_Call : Node_Id;
Result_Subt : Entity_Id) return Boolean;
- -- True if result subtype is definite, or has a size that does not require
+ -- True if result subtype is definite or has a size that does not require
-- secondary stack usage (i.e. no variant part or components whose type
-- depends on discriminants). In particular, untagged types with only
-- access discriminants do not require secondary stack use. Note we must
(Subp_Call : Node_Id;
Subp_Id : Entity_Id) return Boolean;
-- Given a subprogram call to the given subprogram return True if the
- -- names of BIP extra actual and formal parameters match.
+ -- names of BIP extra actual and formal parameters match, and the number
+ -- of actuals (including extra actuals) matches the number of formals.
function Check_Number_Of_Actuals
(Subp_Call : Node_Id;
procedure Expand_Call_Helper (N : Node_Id; Post_Call : out List_Id);
-- Does the main work of Expand_Call. Post_Call is as for Expand_Actuals.
- procedure Expand_Ctrl_Function_Call (N : Node_Id);
+ procedure Expand_Ctrl_Function_Call (N : Node_Id; Use_Sec_Stack : Boolean);
-- 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.
+ -- primary or secondary stack (Use_Sec_Stack says which) using 'reference.
procedure Expand_Non_Function_Return (N : Node_Id);
-- Expand a simple return statement found in a procedure body, entry body,
-- 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.
- function Has_BIP_Extra_Formal
- (E : Entity_Id;
- Kind : BIP_Formal_Kind) return Boolean;
- -- Given a frozen subprogram, subprogram type, entry or entry family,
- -- return True if E has the BIP extra formal associated with Kind. It must
- -- be invoked with a frozen entity or a subprogram type of a dispatching
- -- call since we can only rely on the availability of the extra formals
- -- on these entities.
-
procedure Insert_Post_Call_Actions (N : Node_Id; Post_Call : List_Id);
-- Insert the Post_Call list previously produced by routine Expand_Actuals
-- or Expand_Call_Helper into the tree.
-- If no return object is provided, then pass null
- if not Present (Return_Object) then
+ if No (Return_Object) then
Obj_Address := Make_Null (Loc);
Set_Parent (Obj_Address, Function_Call);
-- Create the actual which is a pointer to the current activation chain
- if No (Chain) then
+ if Restriction_Active (No_Task_Hierarchy) then
+ Chain_Actual := Make_Null (Loc);
+
+ elsif No (Chain) then
Chain_Actual :=
Make_Attribute_Reference (Loc,
Prefix => Make_Identifier (Loc, Name_uChain),
-- 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.
+ -- the extra formals can be created and Returns_By_Ref computed.
if No (Extra_Formal) then
Create_Extra_Formals (Func);
Extra_Formal := Extra_Formals (Func);
+ Compute_Returns_By_Ref (Func);
end if;
-- We search for a formal with a matching suffix. We can't search
(Func_Call : Node_Id;
Result_Subt : Entity_Id) return Boolean
is
+ Utyp : constant Entity_Id := Underlying_Type (Result_Subt);
+
begin
- return
- (Is_Definite_Subtype (Underlying_Type (Result_Subt))
- and then No (Controlling_Argument (Func_Call)))
- or else not Requires_Transient_Scope (Underlying_Type (Result_Subt));
+ return not Needs_Secondary_Stack (Utyp)
+ and then not (Is_Tagged_Type (Utyp)
+ and then Present (Controlling_Argument (Func_Call)));
end Caller_Known_Size;
-----------------------
| N_Function_Call
| N_Procedure_Call_Statement);
+ -- In CodePeer_Mode, the tree for `'Elab_Spec` procedures will be
+ -- malformed because GNAT does not perform the usual expansion that
+ -- results in the importation of external elaboration procedure symbols.
+ -- This is expected: the CodePeer backend has special handling for this
+ -- malformed tree.
+ -- Thus, we do not need to check the tree (and in fact can't, because
+ -- it's malformed).
+
+ if CodePeer_Mode
+ and then Nkind (Name (Subp_Call)) = N_Attribute_Reference
+ and then Attribute_Name (Name (Subp_Call)) in Name_Elab_Spec
+ | Name_Elab_Body
+ | Name_Elab_Subp_Body
+ then
+ return True;
+ end if;
+
Formal := First_Formal_With_Extras (Subp_Id);
Actual := First_Actual (Subp_Call);
Crep := False;
end if;
+ -- If the actual denotes a variable which captures the value of an
+ -- object for validation purposes, we propagate the link with this
+ -- object to the new variable made from the actual just above.
+
+ if Ekind (Formal) /= E_In_Parameter
+ and then Is_Validation_Variable_Reference (Actual)
+ then
+ declare
+ Ref : constant Node_Id := Unqual_Conv (Actual);
+
+ begin
+ if Is_Entity_Name (Ref) then
+ Set_Validated_Object (Var, Validated_Object (Entity (Ref)));
+
+ else
+ pragma Assert (False);
+ null;
+ end if;
+ end;
+ 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).
Expr := New_Occurrence_Of (Temp, Loc);
end if;
- Rewrite (Actual, New_Occurrence_Of (Temp, Loc));
+ Rewrite (Actual, New_Occurrence_Of (Temp, Sloc (Actual)));
Analyze (Actual);
-- If the actual is a conversion of a packed reference, it may
Name => Lhs,
Expression => Expr));
end if;
+
+ -- Add a copy-back to reflect any potential changes in value
+ -- back into the original object, if any.
+
+ if Is_Validation_Variable_Reference (Lhs) then
+ Add_Validation_Call_By_Copy_Code (Lhs);
+ end if;
end;
end if;
end Add_Call_By_Copy_Code;
--------------------------------------
procedure Add_Validation_Call_By_Copy_Code (Act : Node_Id) is
+ Var : constant Node_Id := Unqual_Conv (Act);
+
Expr : Node_Id;
Obj : Node_Id;
Obj_Typ : Entity_Id;
- Var : constant Node_Id := Unqual_Conv (Act);
Var_Id : Entity_Id;
begin
end if;
end if;
- -- The actual denotes a variable which captures the value of an
- -- object for validation purposes. Add a copy-back to reflect any
- -- potential changes in value back into the original object.
-
- -- Var : ... := Object;
- -- if not Var'Valid then -- validity check
- -- Call (Var); -- modify var
- -- Object := Var; -- update Object
-
- -- This case is given higher priority because the subsequent check
- -- for type conversion may add an extra copy of the variable and
- -- prevent proper value propagation back in the original object.
-
- if Is_Validation_Variable_Reference (Actual) then
- Add_Validation_Call_By_Copy_Code (Actual);
-
-- If argument is a type conversion for a type that is passed by
-- copy, then we must pass the parameter by copy.
- elsif Nkind (Actual) = N_Type_Conversion
+ if Nkind (Actual) = N_Type_Conversion
and then
(Is_Elementary_Type (E_Formal)
or else Is_Bit_Packed_Array (Etype (Formal))
and then not In_Subrange_Of (E_Actual, E_Formal)))
then
Add_Call_By_Copy_Code;
+
+ -- The actual denotes a variable which captures the value of an
+ -- object for validation purposes. Add a copy-back to reflect any
+ -- potential changes in value back into the original object.
+
+ -- Var : ... := Object;
+ -- if not Var'Valid then -- validity check
+ -- Call (Var); -- modify var
+ -- Object := Var; -- update Object
+
+ elsif Is_Validation_Variable_Reference (Actual) then
+ Add_Validation_Call_By_Copy_Code (Actual);
end if;
-- RM 3.2.4 (23/3): A predicate is checked on in-out and out
| N_Function_Call
| N_Procedure_Call_Statement);
- -- Check that this is not the call in the body of the wrapper
+ -- Check that this is not the call in the body of the access
+ -- subprogram wrapper or the postconditions wrapper.
if Must_Rewrite_Indirect_Call
and then (not Is_Overloadable (Current_Scope)
- or else not Is_Access_Subprogram_Wrapper (Current_Scope))
+ or else not (Is_Access_Subprogram_Wrapper (Current_Scope)
+ or else
+ (Chars (Current_Scope) = Name_uWrapped_Statements
+ and then Is_Access_Subprogram_Wrapper
+ (Scope (Current_Scope)))))
then
declare
Loc : constant Source_Ptr := Sloc (N);
loop
Aspect_Bearer := Nearest_Ancestor (Aspect_Bearer);
- if not Present (Aspect_Bearer) then
+ if No (Aspect_Bearer) then
return False;
end if;
or else No (Aspect)
-- Do not fold if multiple applicable predicate aspects
- or else Present (Find_Aspect (Subt, Aspect_Static_Predicate))
- or else Present (Find_Aspect (Subt, Aspect_Predicate))
+ or else Has_Aspect (Subt, Aspect_Static_Predicate)
+ or else Has_Aspect (Subt, Aspect_Predicate)
or else Augments_Other_Dynamic_Predicate (Aspect)
or else CodePeer_Mode
then
------------------------------
procedure Check_Subprogram_Variant is
+
+ function Duplicate_Params_Without_Extra_Actuals
+ (Call_Node : Node_Id) return List_Id;
+ -- Duplicate actual parameters of Call_Node into New_Call without
+ -- extra actuals.
+
+ --------------------------------------------
+ -- Duplicate_Params_Without_Extra_Actuals --
+ --------------------------------------------
+
+ function Duplicate_Params_Without_Extra_Actuals
+ (Call_Node : Node_Id) return List_Id
+ is
+ Proc_Id : constant Entity_Id := Entity (Name (Call_Node));
+ Actuals : constant List_Id := Parameter_Associations (Call_Node);
+ NL : List_Id;
+ Actual : Node_Or_Entity_Id;
+ Formal : Entity_Id;
+
+ begin
+ if Actuals = No_List then
+ return No_List;
+
+ else
+ NL := New_List;
+ Actual := First (Actuals);
+ Formal := First_Formal (Proc_Id);
+
+ while Present (Formal)
+ and then Formal /= Extra_Formals (Proc_Id)
+ loop
+ Append (New_Copy (Actual), NL);
+ Next (Actual);
+
+ Next_Formal (Formal);
+ end loop;
+
+ return NL;
+ end if;
+ end Duplicate_Params_Without_Extra_Actuals;
+
+ -- Local variables
+
Variant_Prag : constant Node_Id :=
Get_Pragma (Current_Scope, Pragma_Subprogram_Variant);
+ New_Call : Node_Id;
+ Pragma_Arg1 : Node_Id;
Variant_Proc : Entity_Id;
begin
if Present (Variant_Prag) and then Is_Checked (Variant_Prag) then
- -- Analysis of the pragma rewrites its argument with a reference
- -- to the internally generated procedure.
+ Pragma_Arg1 :=
+ Expression (First (Pragma_Argument_Associations (Variant_Prag)));
+
+ -- If pragma parameter is still an aggregate, it comes from a
+ -- structural variant, which is not expanded and ignored for
+ -- run-time execution.
+
+ if Nkind (Pragma_Arg1) = N_Aggregate then
+ pragma Assert
+ (Chars
+ (First
+ (Choices
+ (First (Component_Associations (Pragma_Arg1))))) =
+ Name_Structural);
+ return;
+ end if;
- Variant_Proc :=
- Entity
- (Expression
- (First
- (Pragma_Argument_Associations (Variant_Prag))));
+ -- Otherwise, analysis of the pragma rewrites its argument with a
+ -- reference to the internally generated procedure.
- Insert_Action (Call_Node,
+ Variant_Proc := Entity (Pragma_Arg1);
+
+ New_Call :=
Make_Procedure_Call_Statement (Loc,
Name =>
New_Occurrence_Of (Variant_Proc, Loc),
Parameter_Associations =>
- New_Copy_List (Parameter_Associations (Call_Node))));
+ Duplicate_Params_Without_Extra_Actuals (Call_Node));
+
+ Insert_Action (Call_Node, New_Call);
+
+ pragma Assert (Etype (New_Call) /= Any_Type
+ or else Serious_Errors_Detected > 0);
end if;
end Check_Subprogram_Variant;
end if;
end if;
+ -- Ensure that the called subprogram has all its formals
+
+ if not Is_Frozen (Subp) then
+ Create_Extra_Formals (Subp);
+ 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
and then Thunk_Entity (Current_Scope) = Subp
and then Present (Extra_Formals (Subp))
then
- pragma Assert (Present (Extra_Formals (Current_Scope)));
+ pragma Assert (Extra_Formals_Match_OK (Current_Scope, Subp));
declare
Target_Formal : Entity_Id;
Add_Actual_Parameter (Remove_Head (Extra_Actuals));
end loop;
+ -- Mark the call as processed build-in-place call; required
+ -- to avoid adding the extra formals twice.
+
+ if Nkind (Call_Node) = N_Function_Call then
+ Set_Is_Expanded_Build_In_Place_Call (Call_Node);
+ end if;
+
Expand_Actuals (Call_Node, Subp, Post_Call);
pragma Assert (Is_Empty_List (Post_Call));
pragma Assert (Check_Number_Of_Actuals (Call_Node, Subp));
then
Must_Inline := not In_Extended_Main_Source_Unit (Subp);
- -- Inline calls to _postconditions when generating C code
+ -- Inline calls to _Wrapped_Statements when generating C
elsif Modify_Tree_For_C
and then In_Same_Extended_Unit (Sloc (Bod), Loc)
- and then Chars (Name (Call_Node)) = Name_uPostconditions
+ and then Chars (Name (Call_Node))
+ = Name_uWrapped_Statements
then
Must_Inline := True;
end 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.
+ -- function call is transformed into a reference to the result that has
+ -- been built either on the primary or the secondary stack.
if Needs_Finalization (Etype (Subp)) then
if not Is_Build_In_Place_Function_Call (Call_Node)
or else
not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
then
- Expand_Ctrl_Function_Call (Call_Node);
+ Expand_Ctrl_Function_Call
+ (Call_Node, Needs_Secondary_Stack (Etype (Subp)));
-- Build-in-place function calls which appear in anonymous contexts
-- need a transient scope to ensure the proper finalization of the
and then
(Ekind (Current_Scope) /= E_Loop
or else Nkind (Parent (Call_Node)) /= N_Function_Call
- or else not Is_Build_In_Place_Function_Call
- (Parent (Call_Node)))
+ or else not
+ Is_Build_In_Place_Function_Call (Parent (Call_Node)))
then
- Establish_Transient_Scope (Call_Node, Manage_Sec_Stack => True);
+ Establish_Transient_Scope
+ (Call_Node, Needs_Secondary_Stack (Etype (Subp)));
end if;
end if;
end Expand_Call_Helper;
-- Expand_Ctrl_Function_Call --
-------------------------------
- procedure Expand_Ctrl_Function_Call (N : Node_Id) is
+ procedure Expand_Ctrl_Function_Call (N : Node_Id; Use_Sec_Stack : Boolean)
+ is
+ Par : constant Node_Id := Parent (N);
+
function Is_Element_Reference (N : Node_Id) return Boolean;
-- Determine whether node N denotes a reference to an Ada 2012 container
-- element.
-- Start of processing for Expand_Ctrl_Function_Call
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.
+ -- Optimization: if the returned value is returned again, then no need
+ -- to copy/readjust/finalize, we can just pass the value through (see
+ -- Expand_N_Simple_Return_Statement), and thus no attachment is needed.
+
+ if Nkind (Par) = N_Simple_Return_Statement then
+ return;
+ end if;
- if Nkind (Parent (N)) = N_Simple_Return_Statement then
+ -- Another optimization: if the returned value is used to initialize an
+ -- object, then no need to copy/readjust/finalize, we can initialize it
+ -- in place. However, if the call returns on the secondary stack or this
+ -- is a special return object, then we need the expansion because we'll
+ -- be renaming the temporary as the (permanent) object.
+
+ if Nkind (Par) = N_Object_Declaration
+ and then not Use_Sec_Stack
+ and then not Is_Special_Return_Object (Defining_Entity (Par))
+ then
return;
end if;
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.
+ -- Apply the transformation, unless it was already applied manually
- Remove_Side_Effects (N);
+ if Nkind (Par) /= N_Reference then
+ Remove_Side_Effects (N);
+ end if;
-- The side effect removal of the function call produced a temporary.
-- When the context is a case expression, if expression, or 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);
-
- function Build_Heap_Or_Pool_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
- -- heap or user-defined storage pool. The object may need finalization
- -- actions depending on the return type.
- --
- -- * Controlled case
- --
- -- if BIPfinalizationmaster = null then
- -- Temp_Id := <Alloc_Expr>;
- -- else
- -- 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;
- --
- -- * Non-controlled case
- --
- -- Temp_Id := <Alloc_Expr>;
- --
- -- 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.
+ Loc : constant Source_Ptr := Sloc (N);
+ Func_Id : constant Entity_Id :=
+ Return_Applies_To (Return_Statement_Entity (N));
+ Is_BIP_Func : constant Boolean :=
+ Is_Build_In_Place_Function (Func_Id);
+ Ret_Obj_Id : constant Entity_Id :=
+ First_Entity (Return_Statement_Entity (N));
+ Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id);
+ Ret_Typ : constant Entity_Id := Etype (Func_Id);
function Move_Activation_Chain (Func_Id : Entity_Id) return Node_Id;
-- Construct a call to System.Tasking.Stages.Move_Activation_Chain
-- Func_Id is the entity of the function where the extended return
-- statement appears.
- ----------------------------------
- -- Build_Heap_Or_Pool_Allocator --
- ----------------------------------
-
- function Build_Heap_Or_Pool_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 objects that require finalization actions
-
- if 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);
- Orig_Expr : constant Node_Id :=
- New_Copy_Tree
- (Source => Alloc_Expr,
- Scopes_In_EWA_OK => True);
- 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_Occurrence_Of (RTE (RE_Root_Storage_Pool), Loc),
- Name =>
- Make_Explicit_Dereference (Loc,
- Prefix =>
- Make_Function_Call (Loc,
- Name =>
- New_Occurrence_Of (RTE (RE_Base_Pool), Loc),
- Parameter_Associations => New_List (
- Make_Explicit_Dereference (Loc,
- Prefix =>
- New_Occurrence_Of (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_Occurrence_Of (Desig_Typ, Loc))));
-
- -- Perform minor decoration in order to set the master and the
- -- storage pool attributes.
-
- Mutate_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_Occurrence_Of (Ptr_Typ, Loc)));
-
- -- Allocate the object, generate:
- -- Local_Id := <Alloc_Expr>;
-
- Append_To (Stmts,
- Make_Assignment_Statement (Loc,
- Name => New_Occurrence_Of (Local_Id, Loc),
- Expression => Alloc_Expr));
-
- -- Generate:
- -- Temp_Id := Temp_Typ (Local_Id);
-
- Append_To (Stmts,
- Make_Assignment_Statement (Loc,
- Name => New_Occurrence_Of (Temp_Id, Loc),
- Expression =>
- Unchecked_Convert_To (Temp_Typ,
- New_Occurrence_Of (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
- -- Temp_Id := <Orig_Expr>;
- -- else
- -- declare
- -- <Decls>
- -- begin
- -- <Stmts>
- -- end;
- -- end if;
-
- return
- Make_If_Statement (Loc,
- Condition =>
- Make_Op_Eq (Loc,
- Left_Opnd => New_Occurrence_Of (Fin_Mas_Id, Loc),
- Right_Opnd => Make_Null (Loc)),
-
- Then_Statements => New_List (
- Make_Assignment_Statement (Loc,
- Name => New_Occurrence_Of (Temp_Id, Loc),
- Expression => Orig_Expr)),
-
- Else_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_Occurrence_Of (Temp_Id, Loc),
- Expression => Alloc_Expr);
- end if;
- end Build_Heap_Or_Pool_Allocator;
-
---------------------------
-- Move_Activation_Chain --
---------------------------
-- Local variables
- Func_Id : constant Entity_Id :=
- Return_Applies_To (Return_Statement_Entity (N));
- Is_BIP_Func : constant Boolean :=
- Is_Build_In_Place_Function (Func_Id);
- Ret_Obj_Id : constant Entity_Id :=
- First_Entity (Return_Statement_Entity (N));
- Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id);
- Ret_Typ : constant Entity_Id := Etype (Func_Id);
-
Exp : Node_Id;
HSS : Node_Id;
Result : Node_Id;
- Stmts : List_Id;
+ Stmts : List_Id := No_List;
Return_Stmt : Node_Id := Empty;
-- Force initialization to facilitate static analysis
-- Assert that if F says "return R : T := G(...) do..."
-- then F and G are both b-i-p, or neither b-i-p.
- if Nkind (Exp) = N_Function_Call then
+ if Present (Exp) and then Nkind (Exp) = N_Function_Call then
pragma Assert (Ekind (Current_Subprogram) = E_Function);
pragma Assert
(Is_Build_In_Place_Function (Current_Subprogram) =
null;
end if;
- -- Ada 2005 (AI95-344): 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.
-
- -- AI12-043: The check is made immediately after the return object
- -- is created.
-
- if Present (Exp) and then Is_Class_Wide_Type (Ret_Typ) then
- Apply_CW_Accessibility_Check (Exp, Func_Id);
- end if;
else
Exp := Empty;
end if;
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;
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
- -- 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_BIP_Func
- and then Nkind (Ret_Obj_Decl) = N_Object_Renaming_Declaration
- then
- pragma Assert
- (Nkind (Original_Node (Ret_Obj_Decl)) = N_Object_Declaration
- and then
+ -- Build a simple_return_statement that returns the return object
- -- It is a regular BIP object declaration
+ Return_Stmt :=
+ Make_Simple_Return_Statement (Loc,
+ Expression => New_Occurrence_Of (Ret_Obj_Id, Loc));
+ Append_To (Stmts, Return_Stmt);
- (Is_Build_In_Place_Function_Call
- (Expression (Original_Node (Ret_Obj_Decl)))
+ -- Case where we do not need to build a block. But we're about to drop
+ -- Return_Object_Declarations on the floor, so assert that it contains
+ -- only the return object declaration.
- -- It is a BIP object declaration that displaces the pointer
- -- to the object to reference a converted interface type.
+ else pragma Assert (List_Length (Return_Object_Declarations (N)) = 1);
- or else
- Present (Unqual_BIP_Iface_Function_Call
- (Expression (Original_Node (Ret_Obj_Decl))))));
+ -- Build simple_return_statement that returns the expression directly
- -- Return the build-in-place result by reference
+ Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => Exp);
+ Result := Return_Stmt;
+ end if;
- Set_By_Ref (Return_Stmt);
+ -- Set the flag to prevent infinite recursion
- elsif Is_BIP_Func then
+ Set_Comes_From_Extended_Return_Statement (Return_Stmt);
+ Set_Return_Statement (Ret_Obj_Id, Return_Stmt);
- -- 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.
+ Rewrite (N, Result);
- -- declare
- -- Result : T [:= <expression>];
- -- begin
- -- ...
+ -- AI12-043: The checks of 6.5(8.1/3) and 6.5(21/3) are made immediately
+ -- before an object is returned. A predicate that applies to the return
+ -- subtype is checked immediately before an object is returned.
- -- is converted to
+ Analyze (N);
+ end Expand_N_Extended_Return_Statement;
- -- declare
- -- Result : T renames FuncRA.all;
- -- [Result := <expression;]
- -- begin
- -- ...
+ ----------------------------
+ -- Expand_N_Function_Call --
+ ----------------------------
- declare
- Ret_Obj_Expr : constant Node_Id := Expression (Ret_Obj_Decl);
- Ret_Obj_Typ : constant Entity_Id := Etype (Ret_Obj_Id);
+ procedure Expand_N_Function_Call (N : Node_Id) is
+ begin
+ Expand_Call (N);
+ end Expand_N_Function_Call;
- Init_Assignment : Node_Id := Empty;
- Obj_Acc_Formal : Entity_Id;
- Obj_Acc_Deref : Node_Id;
- Obj_Alloc_Formal : Entity_Id;
+ ---------------------------------------
+ -- Expand_N_Procedure_Call_Statement --
+ ---------------------------------------
- begin
- -- Build-in-place results must be returned by reference
-
- Set_By_Ref (Return_Stmt);
-
- -- Retrieve the implicit access parameter passed by the caller
-
- Obj_Acc_Formal :=
- Build_In_Place_Formal (Func_Id, 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 (Ret_Obj_Expr)
- and then not No_Initialization (Ret_Obj_Decl)
- and then not Is_Interface (Ret_Obj_Typ)
- then
- Init_Assignment :=
- Make_Assignment_Statement (Loc,
- Name => New_Occurrence_Of (Ret_Obj_Id, Loc),
- Expression =>
- New_Copy_Tree
- (Source => Ret_Obj_Expr,
- Scopes_In_EWA_OK => True));
+ procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is
+ begin
+ Expand_Call (N);
+ end Expand_N_Procedure_Call_Statement;
- Set_Etype (Name (Init_Assignment), Etype (Ret_Obj_Id));
- Set_Assignment_OK (Name (Init_Assignment));
- Set_No_Ctrl_Actions (Init_Assignment);
+ ------------------------------------
+ -- Expand_N_Return_When_Statement --
+ ------------------------------------
- Set_Parent (Name (Init_Assignment), Init_Assignment);
- Set_Parent (Expression (Init_Assignment), Init_Assignment);
+ procedure Expand_N_Return_When_Statement (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ begin
+ Rewrite (N,
+ Make_If_Statement (Loc,
+ Condition => Condition (N),
+ Then_Statements => New_List (
+ Make_Simple_Return_Statement (Loc,
+ Expression => Expression (N)))));
- Set_Expression (Ret_Obj_Decl, Empty);
+ Analyze (N);
+ end Expand_N_Return_When_Statement;
- if Is_Class_Wide_Type (Etype (Ret_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 (Ret_Obj_Id), Loc),
- Expression =>
- Relocate_Node (Expression (Init_Assignment))));
- end if;
+ --------------------------------------
+ -- Expand_N_Simple_Return_Statement --
+ --------------------------------------
- -- 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, tagged, and controlled result subtypes).
-
- if not Needs_BIP_Alloc_Form (Func_Id) then
- Insert_After (Ret_Obj_Decl, Init_Assignment);
- end if;
- end if;
-
- -- When the function's subtype is unconstrained, a run-time
- -- test may be needed to decide 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. 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 Needs_BIP_Alloc_Form (Func_Id) then
- Obj_Alloc_Formal :=
- Build_In_Place_Formal (Func_Id, 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;
- Guard_Except : 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
- -- 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_Occurrence_Of (Ret_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_Occurrence_Of (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 (Ret_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_Occurrence_Of
- (Etype (Ret_Obj_Expr), Loc),
- Expression =>
- New_Copy_Tree
- (Source => Ret_Obj_Expr,
- Scopes_In_EWA_OK => True)));
-
- 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 (Ret_Obj_Typ) then
- Heap_Allocator :=
- Make_Allocator (Loc,
- Expression =>
- New_Occurrence_Of
- (Etype (Ret_Obj_Expr), Loc));
- else
- Heap_Allocator :=
- Make_Allocator (Loc,
- Expression =>
- New_Occurrence_Of (Ret_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;
-
- -- Set the flag indicating that the allocator came from
- -- a build-in-place return statement, so we can avoid
- -- adjusting the allocated object. Note that this flag
- -- will be inherited by the copies made below.
-
- Set_Alloc_For_BIP_Return (Heap_Allocator);
-
- -- 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
- (Source => Heap_Allocator,
- Scopes_In_EWA_OK => True);
-
- pragma Assert (Alloc_For_BIP_Return (Pool_Allocator));
-
- -- Do not generate the renaming of the build-in-place
- -- pool parameter on ZFP because the parameter is not
- -- created in the first place.
-
- if RTE_Available (RE_Root_Storage_Pool_Ptr) then
- Pool_Decl :=
- Make_Object_Renaming_Declaration (Loc,
- Defining_Identifier => Pool_Id,
- Subtype_Mark =>
- New_Occurrence_Of
- (RTE (RE_Root_Storage_Pool), Loc),
- Name =>
- Make_Explicit_Dereference (Loc,
- New_Occurrence_Of
- (Build_In_Place_Formal
- (Func_Id, 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
- (Source => Heap_Allocator,
- Scopes_In_EWA_OK => True);
-
- pragma Assert (Alloc_For_BIP_Return (SS_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
-
- Check_Restriction (No_Secondary_Stack, N);
- 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
- -- all blocks 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_Uses_Sec_Stack (Func_Id);
- Set_Uses_Sec_Stack (Return_Statement_Entity (N));
- Set_Sec_Stack_Needed_For_Return
- (Return_Statement_Entity (N));
- Set_Enclosing_Sec_Stack_Return (N);
-
- -- Guard against poor expansion on the caller side by
- -- using a raise statement to catch out-of-range values
- -- of formal parameter BIP_Alloc_Form.
-
- if Exceptions_OK then
- Guard_Except :=
- Make_Raise_Program_Error (Loc,
- Reason => PE_Build_In_Place_Mismatch);
- else
- Guard_Except := Make_Null_Statement (Loc);
- 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_Occurrence_Of (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_Occurrence_Of (Alloc_Obj_Id, Loc),
- Expression =>
- Unchecked_Convert_To
- (Ref_Type,
- New_Occurrence_Of (Obj_Acc_Formal, Loc)))),
-
- Elsif_Parts => New_List (
- Make_Elsif_Part (Loc,
- Condition =>
- Make_Op_Eq (Loc,
- Left_Opnd =>
- New_Occurrence_Of (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_Occurrence_Of (Alloc_Obj_Id, Loc),
- Expression => SS_Allocator))),
-
- Make_Elsif_Part (Loc,
- Condition =>
- Make_Op_Eq (Loc,
- Left_Opnd =>
- New_Occurrence_Of (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_Or_Pool_Allocator
- (Temp_Id => Alloc_Obj_Id,
- Temp_Typ => Ref_Type,
- Func_Id => Func_Id,
- Ret_Typ => Ret_Obj_Typ,
- Alloc_Expr => Heap_Allocator))),
-
- -- ???If all is well, we can put the following
- -- 'elsif' in the 'else', but this is a useful
- -- self-check in case caller and callee don't agree
- -- on whether BIPAlloc and so on should be passed.
-
- Make_Elsif_Part (Loc,
- Condition =>
- Make_Op_Eq (Loc,
- Left_Opnd =>
- New_Occurrence_Of (Obj_Alloc_Formal, Loc),
- Right_Opnd =>
- Make_Integer_Literal (Loc,
- UI_From_Int (BIP_Allocation_Form'Pos
- (User_Storage_Pool)))),
-
- Then_Statements => New_List (
- Pool_Decl,
- Build_Heap_Or_Pool_Allocator
- (Temp_Id => Alloc_Obj_Id,
- Temp_Typ => Ref_Type,
- Func_Id => Func_Id,
- Ret_Typ => Ret_Obj_Typ,
- Alloc_Expr => Pool_Allocator)))),
-
- -- Raise Program_Error if it's none of the above;
- -- this is a compiler bug.
-
- Else_Statements => New_List (Guard_Except));
-
- -- 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_Occurrence_Of (Alloc_Obj_Id, Loc)));
- pragma Assert
- (Assignment_OK
- (Original_Node (Name (Init_Assignment))));
- Set_Assignment_OK (Name (Init_Assignment));
-
- Set_Etype (Name (Init_Assignment), Etype (Ret_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.
-
- Obj_Acc_Formal := Alloc_Obj_Id;
- end;
-
- -- When the function's subtype is unconstrained and a run-time
- -- test is not needed, we nevertheless need to build the return
- -- using the function's result subtype.
-
- elsif not Is_Constrained (Underlying_Type (Etype (Func_Id)))
- then
- declare
- Alloc_Obj_Id : Entity_Id;
- Alloc_Obj_Decl : Node_Id;
- Ptr_Type_Decl : Node_Id;
- Ref_Type : Entity_Id;
-
- begin
- -- 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_Occurrence_Of (Ret_Obj_Typ, Loc)));
-
- Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl);
-
- -- Create an access object initialized to the conversion
- -- of the implicit access value passed in by the caller.
-
- Alloc_Obj_Id := Make_Temporary (Loc, 'R');
- Set_Etype (Alloc_Obj_Id, Ref_Type);
-
- -- See the ??? comment a few lines above about the use of
- -- an unchecked conversion here.
-
- Alloc_Obj_Decl :=
- Make_Object_Declaration (Loc,
- Defining_Identifier => Alloc_Obj_Id,
- Object_Definition =>
- New_Occurrence_Of (Ref_Type, Loc),
- Expression =>
- Unchecked_Convert_To
- (Ref_Type,
- New_Occurrence_Of (Obj_Acc_Formal, Loc)));
-
- Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl);
-
- -- Remember the local access object for use in the
- -- dereference of the renaming created below.
-
- Obj_Acc_Formal := 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_Occurrence_Of (Obj_Acc_Formal, Loc));
-
- Rewrite (Ret_Obj_Decl,
- Make_Object_Renaming_Declaration (Loc,
- Defining_Identifier => Ret_Obj_Id,
- Access_Definition => Empty,
- Subtype_Mark => New_Occurrence_Of (Ret_Obj_Typ, Loc),
- Name => Obj_Acc_Deref));
-
- Set_Renamed_Object (Ret_Obj_Id, Obj_Acc_Deref);
- end;
- end if;
-
- -- Case where we do not need to build a block. But we're about to drop
- -- Return_Object_Declarations on the floor, so assert that it contains
- -- only the return object declaration.
-
- else pragma Assert (List_Length (Return_Object_Declarations (N)) = 1);
-
- -- 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);
- Set_Return_Statement (Ret_Obj_Id, Return_Stmt);
-
- Rewrite (N, Result);
-
- -- AI12-043: The checks of 6.5(8.1/3) and 6.5(21/3) are made immediately
- -- before an object is returned. A predicate that applies to the return
- -- subtype is checked immediately before an object is returned.
-
- -- Suppress access checks to avoid generating extra checks for b-i-p.
-
- Analyze (N, Suppress => Access_Check);
- end Expand_N_Extended_Return_Statement;
-
- ----------------------------
- -- Expand_N_Function_Call --
- ----------------------------
-
- procedure Expand_N_Function_Call (N : Node_Id) is
- begin
- Expand_Call (N);
- 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_Return_When_Statement --
- ------------------------------------
-
- procedure Expand_N_Return_When_Statement (N : Node_Id) is
- Loc : constant Source_Ptr := Sloc (N);
- begin
- Rewrite (N,
- Make_If_Statement (Loc,
- Condition => Condition (N),
- Then_Statements => New_List (
- Make_Simple_Return_Statement (Loc,
- Expression => Expression (N)))));
-
- Analyze (N);
- end Expand_N_Return_When_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).
+ 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
Append_To (Stmts, Stmt);
Set_Analyzed (Stmt);
- -- Call the _Postconditions procedure if the related subprogram
- -- has contract assertions that need to be verified on exit.
-
- -- Also, mark the successful return to signal that postconditions
- -- need to be evaluated when finalization occurs by setting
- -- Return_Success_For_Postcond to be True.
-
- if Ekind (Spec_Id) = E_Procedure
- and then Present (Postconditions_Proc (Spec_Id))
- then
- -- Generate:
- --
- -- Return_Success_For_Postcond := True;
- -- if Postcond_Enabled then
- -- _postconditions;
- -- end if;
-
- Insert_Action (Stmt,
- Make_Assignment_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Get_Return_Success_For_Postcond (Spec_Id), Loc),
- Expression => New_Occurrence_Of (Standard_True, Loc)));
-
- -- Wrap the call to _postconditions within a test of the
- -- Postcond_Enabled flag to delay postcondition evaluation
- -- until after finalization when required.
-
- Insert_Action (Stmt,
- Make_If_Statement (Loc,
- Condition =>
- New_Occurrence_Of (Get_Postcond_Enabled (Spec_Id), Loc),
- Then_Statements => New_List (
- Make_Procedure_Call_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Postconditions_Proc (Spec_Id), Loc)))));
- end if;
-
-- Ada 2022 (AI12-0279): append the call to 'Yield unless this is
-- a generic subprogram (since in such case it will be added to
-- the instantiations).
Lab_Node : Node_Id;
begin
- -- Call the _Postconditions procedure if the related subprogram has
- -- contract assertions that need to be verified on exit.
-
- -- Also, mark the successful return to signal that postconditions need
- -- to be evaluated when finalization occurs.
-
- if Ekind (Scope_Id) in E_Entry | E_Entry_Family | E_Procedure
- and then Present (Postconditions_Proc (Scope_Id))
- then
- -- Generate:
- --
- -- Return_Success_For_Postcond := True;
- -- if Postcond_Enabled then
- -- _postconditions;
- -- end if;
-
- Insert_Action (N,
- Make_Assignment_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Get_Return_Success_For_Postcond (Scope_Id), Loc),
- Expression => New_Occurrence_Of (Standard_True, Loc)));
-
- -- Wrap the call to _postconditions within a test of the
- -- Postcond_Enabled flag to delay postcondition evaluation until
- -- after finalization when required.
-
- Insert_Action (N,
- Make_If_Statement (Loc,
- Condition =>
- New_Occurrence_Of (Get_Postcond_Enabled (Scope_Id), Loc),
- Then_Statements => New_List (
- Make_Procedure_Call_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Postconditions_Proc (Scope_Id), Loc)))));
- end if;
-
-- Ada 2022 (AI12-0279)
if Has_Yield_Aspect (Scope_Id)
-- The object may be a component of some other data structure, in which
-- case this must be handled as an inter-object call.
- if not In_Open_Scopes (Scop)
+ if not Scope_Within_Or_Same (Inner => Current_Scope, Outer => Scop)
or else Is_Entry_Wrapper (Current_Scope)
or else not Is_Entity_Name (Name (N))
then
pragma Assert (Present (Exp));
Exp_Is_Function_Call : constant Boolean :=
- Nkind (Exp) = N_Function_Call
- or else (Nkind (Exp) = N_Explicit_Dereference
- and then Is_Entity_Name (Prefix (Exp))
- and then Ekind (Entity (Prefix (Exp))) = E_Constant
- and then Is_Related_To_Func_Return (Entity (Prefix (Exp))));
+ Nkind (Exp) = N_Function_Call or else Is_Captured_Function_Call (Exp);
Exp_Typ : constant Entity_Id := Etype (Exp);
-- The type of the expression (not necessarily the same as R_Type)
if Nkind (Exp) = N_Function_Call then
pragma Assert (Ekind (Scope_Id) = E_Function);
+
+ -- This assertion works fine because Is_Build_In_Place_Function_Call
+ -- returns True for BIP function calls but also for function calls
+ -- that have BIP formals.
+
pragma Assert
- (Is_Build_In_Place_Function (Scope_Id) =
+ (Has_BIP_Formals (Scope_Id) =
Is_Build_In_Place_Function_Call (Exp));
null;
end if;
-- 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.
-
pragma Assert
(Comes_From_Extended_Return_Statement (N)
or else not Is_Build_In_Place_Function_Call (Exp)
- or else Is_Build_In_Place_Function (Scope_Id));
+ or else Has_BIP_Formals (Scope_Id));
if not Comes_From_Extended_Return_Statement (N)
and then Is_Build_In_Place_Function (Scope_Id)
- and then not Debug_Flag_Dot_L
-- The functionality of interface thunks is simple and it is always
-- handled by means of simple return statements. This leaves their
-- 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).
+ -- Nothing to do if we are returning by reference
- if Is_Build_In_Place_Function (Scope_Id)
- or else Is_Limited_Interface (Exp_Typ)
- then
+ if Is_Build_In_Place_Function (Scope_Id) then
+ -- Prevent the reclamation of the secondary stack by all enclosing
+ -- blocks and loops as well as the related function; otherwise the
+ -- result would be reclaimed too early.
+
+ if Needs_BIP_Alloc_Form (Scope_Id) then
+ Set_Enclosing_Sec_Stack_Return (N);
+ end if;
+
+ elsif Is_Limited_View (R_Type) then
null;
-- No copy needed for thunks returning interface type objects since
null;
-- If the call is within a thunk and the type is a limited view, the
- -- backend will eventually see the non-limited view of the type.
+ -- back end will eventually see the non-limited view of the type.
elsif Is_Thunk (Scope_Id) and then Is_Incomplete_Type (Exp_Typ) then
return;
-- A return statement from an ignored Ghost function does not use the
-- secondary stack (or any other one).
- elsif not Requires_Transient_Scope (R_Type)
+ elsif (not Needs_Secondary_Stack (R_Type)
+ and then not Is_Secondary_Stack_Thunk (Scope_Id))
or else Is_Ignored_Ghost_Entity (Scope_Id)
then
-
-- Mutable records with variable-length components are not returned
-- on the sec-stack, so we need to make sure that the back end will
-- only copy back the size of the actual value, and not the maximum
Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exp_Typ));
Decl : Node_Id;
Ent : Entity_Id;
+
begin
if not Exp_Is_Function_Call
- and then Has_Discriminants (Ubt)
+ and then Has_Defaulted_Discriminants (Ubt)
and then not Is_Constrained (Ubt)
and then not Has_Unchecked_Union (Ubt)
then
end if;
end;
+ -- For types which need finalization, do the allocation on the return
+ -- stack manually in order to call Adjust at the right time:
+
+ -- type Ann is access R_Type;
+ -- for Ann'Storage_pool use rs_pool;
+ -- Rnn : constant Ann := new Exp_Typ'(Exp);
+ -- return Rnn.all;
+
+ -- but optimize the case where the result is a function call that
+ -- also needs finalization. In this case the result can directly be
+ -- allocated on the return stack of the caller and no further
+ -- processing is required. Likewise if this is a return object.
+
+ if Comes_From_Extended_Return_Statement (N) then
+ null;
+
+ elsif Present (Utyp)
+ and then Needs_Finalization (Utyp)
+ and then not (Exp_Is_Function_Call
+ and then Needs_Finalization (Exp_Typ))
+ then
+ declare
+ Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
+
+ Alloc_Node : Node_Id;
+ Temp : Entity_Id;
+
+ begin
+ Mutate_Ekind (Acc_Typ, E_Access_Type);
+
+ Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_RS_Pool));
+
+ -- This is an allocator for the return 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_Occurrence_Of (Exp_Typ, 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_Actions (Exp, 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,
+ Constant_Present => True,
+ Object_Definition => New_Occurrence_Of (Acc_Typ, Loc),
+ Expression => Alloc_Node)));
+
+ Rewrite (Exp,
+ Make_Explicit_Dereference (Loc,
+ Prefix => New_Occurrence_Of (Temp, Loc)));
+
+ Analyze_And_Resolve (Exp, R_Type);
+ end;
+ end if;
+
-- Here if secondary stack is used
else
Set_Enclosing_Sec_Stack_Return (N);
+ -- Nothing else to do for a return object
+
+ if Comes_From_Extended_Return_Statement (N) then
+ null;
+
-- Optimize the case where the result is a function call that also
-- returns on the secondary stack. In this case the result is already
- -- on the secondary stack 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
- -- wrong in the case of a controlled type, where gigi does not know
- -- how to do a copy.)
-
- pragma Assert (Requires_Transient_Scope (R_Type));
- if Exp_Is_Function_Call and then Requires_Transient_Scope (Exp_Typ)
- then
- Set_By_Ref (N);
+ -- on the secondary stack and no further processing is required.
+ elsif Exp_Is_Function_Call
+ and then Needs_Secondary_Stack (Exp_Typ)
+ then
-- Remove side effects from the expression now so that other parts
-- of the expander do not have to reanalyze this node without this
-- optimization
Analyze_And_Resolve (Exp, R_Type);
- -- For controlled types, do the allocation on the secondary stack
- -- manually in order to call adjust at the right time:
+ -- For types which both need finalization and are returned on the
+ -- secondary stack, do the allocation on 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;
+ -- type Ann is access R_Type;
+ -- for Ann'Storage_pool use ss_pool;
+ -- Rnn : constant Ann := new Exp_Typ'(Exp);
+ -- return Rnn.all;
- -- We do the same for classwide types that are not potentially
+ -- And we do the same for class-wide 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
+ -- But optimize the case where the result is a function call that
+ -- also needs finalization. In this case the result can directly be
+ -- allocated on the secondary stack and no further processing is
+ -- required.
+
+ elsif CW_Or_Needs_Finalization (Utyp)
+ and then not (Exp_Is_Function_Call
+ and then Needs_Finalization (Exp_Typ))
+ then
declare
- Loc : constant Source_Ptr := Sloc (N);
- Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
+ Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A');
+
Alloc_Node : Node_Id;
Temp : Entity_Id;
begin
Mutate_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
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
+ Constant_Present => True,
Object_Definition => New_Occurrence_Of (Acc_Typ, Loc),
Expression => Alloc_Node)));
end;
end if;
- -- Call the _Postconditions procedure if the related function has
- -- contract assertions that need to be verified on exit.
-
- if Ekind (Scope_Id) = E_Function
- and then Present (Postconditions_Proc (Scope_Id))
- then
- -- In the case of discriminated objects, we have created a
- -- constrained subtype above, and used the underlying type. This
- -- transformation is post-analysis and harmless, except that now the
- -- call to the post-condition will be analyzed and the type kinds
- -- have to match.
-
- if Nkind (Exp) = N_Unchecked_Type_Conversion
- and then Is_Private_Type (R_Type) /= Is_Private_Type (Etype (Exp))
- then
- Rewrite (Exp, Expression (Relocate_Node (Exp)));
- end if;
-
- -- 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.
-
- Force_Evaluation (Exp, Mode => Strict);
-
- -- Save the return value or a pointer to the return value since we
- -- may need to call postconditions after finalization when cleanup
- -- actions are present.
-
- -- Generate:
- --
- -- Result_Object_For_Postcond := [Exp]'Unrestricted_Access;
-
- Insert_Action (Exp,
- Make_Assignment_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Get_Result_Object_For_Postcond (Scope_Id), Loc),
- Expression =>
- (if Is_Elementary_Type (Etype (R_Type)) then
- New_Copy_Tree (Exp)
- else
- Make_Attribute_Reference (Loc,
- Attribute_Name => Name_Unrestricted_Access,
- Prefix => New_Copy_Tree (Exp)))));
-
- -- Mark the successful return to signal that postconditions need to
- -- be evaluated when finalization occurs.
-
- -- Generate:
- --
- -- Return_Success_For_Postcond := True;
- -- if Postcond_Enabled then
- -- _Postconditions ([exp]);
- -- end if;
-
- Insert_Action (Exp,
- Make_Assignment_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Get_Return_Success_For_Postcond (Scope_Id), Loc),
- Expression => New_Occurrence_Of (Standard_True, Loc)));
-
- -- Wrap the call to _postconditions within a test of the
- -- Postcond_Enabled flag to delay postcondition evaluation until
- -- after finalization when required.
-
- Insert_Action (Exp,
- Make_If_Statement (Loc,
- Condition =>
- New_Occurrence_Of (Get_Postcond_Enabled (Scope_Id), Loc),
- Then_Statements => New_List (
- Make_Procedure_Call_Statement (Loc,
- Name =>
- New_Occurrence_Of
- (Postconditions_Proc (Scope_Id), Loc),
- Parameter_Associations => New_List (New_Copy_Tree (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
-----------------------
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,
- Iface => Related_Type (Node (Iface_DT_Ptr)));
-
- if Present (Thunk_Code) then
- Insert_Actions_After (N, New_List (
- Thunk_Code,
-
- Build_Set_Predefined_Prim_Op_Address (Loc,
- Tag_Node =>
- New_Occurrence_Of (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_Occurrence_Of (Thunk_Id, Loc),
- Attribute_Name => Name_Unrestricted_Access))),
-
- Build_Set_Predefined_Prim_Op_Address (Loc,
- Tag_Node =>
- New_Occurrence_Of
- (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_Occurrence_Of (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
-
+ Loc : constant Source_Ptr := Sloc (N);
Subp : constant Entity_Id := Entity (N);
- -- Start of processing for Freeze_Subprogram
-
begin
-- We suppress the initialization of the dispatch table entry when
-- not Tagged_Type_Expansion because the dispatching mechanism is
or else Present (Interface_Alias (Subp))
then
if Is_Predefined_Dispatching_Operation (Subp) then
- Register_Predefined_DT_Entry (Subp);
+ L := Register_Predefined_Primitive (Loc, Subp);
+ else
+ L := New_List;
end if;
- L := Register_Primitive (Loc, Prim => Subp);
+ Append_List_To (L, Register_Primitive (Loc, Subp));
if Is_Empty_List (L) then
null;
--------------------------
function Has_BIP_Extra_Formal
- (E : Entity_Id;
- Kind : BIP_Formal_Kind) return Boolean
+ (E : Entity_Id;
+ Kind : BIP_Formal_Kind;
+ Must_Be_Frozen : Boolean := True) return Boolean
is
Extra_Formal : Entity_Id := Extra_Formals (E);
-- extra formals are added when the target subprogram is frozen; see
-- Expand_Dispatching_Call).
- pragma Assert (Is_Frozen (E)
+ pragma Assert ((Is_Frozen (E) or else not Must_Be_Frozen)
or else (Ekind (E) = E_Subprogram_Type
and then Is_Dispatch_Table_Entity (E))
or else (Is_Dispatching_Operation (E)
Remove_Side_Effects (A);
- if Is_Controlling_Actual (A)
- and then Etype (F) /= Etype (A)
- then
+ -- Ensure matching types to avoid reporting spurious errors since
+ -- the called helper may have been built for a parent type.
+
+ if Etype (F) /= Etype (A) then
Append_To (Actuals,
- Make_Unchecked_Type_Conversion (Loc,
- New_Occurrence_Of (Etype (F), Loc),
- New_Copy_Tree (A)));
+ Unchecked_Convert_To (Etype (F), New_Copy_Tree (A)));
else
Append_To (Actuals, New_Copy_Tree (A));
end if;
end if;
end Install_Class_Preconditions_Check;
- -----------------------------------
- -- Is_Build_In_Place_Result_Type --
- -----------------------------------
-
- function Is_Build_In_Place_Result_Type (Typ : Entity_Id) return Boolean is
- begin
- if not Expander_Active then
- return False;
- end if;
-
- -- 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.
-
- if Is_Limited_View (Typ) then
- return Ada_Version >= Ada_2005 and then not Debug_Flag_Dot_L;
-
- else
- if Debug_Flag_Dot_9 then
- return False;
- end if;
-
- if Has_Interfaces (Typ) then
- return False;
- end if;
-
- declare
- T : Entity_Id := Typ;
- begin
- -- For T'Class, return True if it's True for T. This is necessary
- -- because a class-wide function might say "return F (...)", where
- -- F returns the corresponding specific type. We need a loop in
- -- case T is a subtype of a class-wide type.
-
- while Is_Class_Wide_Type (T) loop
- T := Etype (T);
- end loop;
-
- -- If this is a generic formal type in an instance, return True if
- -- it's True for the generic actual type.
-
- if Nkind (Parent (T)) = N_Subtype_Declaration
- and then Present (Generic_Parent_Type (Parent (T)))
- then
- T := Entity (Subtype_Indication (Parent (T)));
-
- if Present (Full_View (T)) then
- T := Full_View (T);
- end if;
- end if;
-
- if Present (Underlying_Type (T)) then
- T := Underlying_Type (T);
- end if;
-
- declare
- Result : Boolean;
- -- So we can stop here in the debugger
- begin
- -- ???For now, enable build-in-place for a very narrow set of
- -- controlled types. Change "if True" to "if False" to
- -- experiment with more controlled types. Eventually, we might
- -- like to enable build-in-place for all tagged types, all
- -- types that need finalization, and all caller-unknown-size
- -- types.
-
- if True then
- Result := Is_Controlled (T)
- and then not Is_Generic_Actual_Type (T)
- and then Present (Enclosing_Subprogram (T))
- and then not Is_Compilation_Unit (Enclosing_Subprogram (T))
- and then Ekind (Enclosing_Subprogram (T)) = E_Procedure;
- else
- Result := Is_Controlled (T);
- end if;
-
- return Result;
- end;
- end;
- end if;
- end Is_Build_In_Place_Result_Type;
-
------------------------------
-- Is_Build_In_Place_Entity --
------------------------------
--------------------------------
function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is
+ Kind : constant Entity_Kind := Ekind (E);
+ Typ : constant Entity_Id := Etype (E);
+
begin
-- This function is called from Expand_Subtype_From_Expr during
-- semantic analysis, even when expansion is off. In those cases
return False;
end if;
- if Ekind (E) in E_Function | E_Generic_Function
- or else (Ekind (E) = E_Subprogram_Type
- and then Etype (E) /= Standard_Void_Type)
- then
- -- If the function is imported from a foreign language, we don't do
- -- build-in-place. Note that Import (Ada) functions can do
- -- build-in-place. Note that it is OK for a build-in-place function
- -- to return a type with a foreign convention; the build-in-place
- -- machinery will ensure there is no copying.
-
- return Is_Build_In_Place_Result_Type (Etype (E))
- and then not (Has_Foreign_Convention (E) and then Is_Imported (E))
- and then not Debug_Flag_Dot_L;
- else
- return False;
- end if;
+ -- If the function is imported from a foreign language, we don't do
+ -- build-in-place, whereas Import (Ada) functions can do it. Note also
+ -- that it is OK for a build-in-place function to return a type with a
+ -- foreign convention because the machinery ensures there is no copying.
+
+ return (Kind in E_Function | E_Generic_Function
+ or else
+ (Kind = E_Subprogram_Type and then Typ /= Standard_Void_Type))
+ and then Is_Build_In_Place_Result_Type (Typ)
+ and then not Has_Foreign_Convention (E);
end Is_Build_In_Place_Function;
-------------------------------------
raise Program_Error;
end if;
- declare
- Result : constant Boolean := Is_Build_In_Place_Function (Function_Id);
- -- So we can stop here in the debugger
- begin
- return Result;
- end;
+ if Is_Build_In_Place_Function (Function_Id) then
+ return True;
+
+ -- True also if the function has BIP Formals
+
+ else
+ declare
+ Kind : constant Entity_Kind := Ekind (Function_Id);
+
+ begin
+ if (Kind in E_Function | E_Generic_Function
+ or else (Kind = E_Subprogram_Type
+ and then
+ Etype (Function_Id) /= Standard_Void_Type))
+ and then Has_BIP_Formals (Function_Id)
+ then
+ -- So we can stop here in the debugger
+ return True;
+ else
+ return False;
+ end if;
+ end;
+ end if;
end Is_Build_In_Place_Function_Call;
+ -----------------------------------
+ -- Is_Build_In_Place_Result_Type --
+ -----------------------------------
+
+ function Is_Build_In_Place_Result_Type (Typ : Entity_Id) return Boolean is
+ begin
+ if not Expander_Active then
+ return False;
+ end if;
+
+ -- 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.
+
+ return Is_Limited_View (Typ)
+ and then Ada_Version >= Ada_2005
+ and then not Debug_Flag_Dot_L;
+ end Is_Build_In_Place_Result_Type;
+
+ -------------------------------------
+ -- Is_Build_In_Place_Return_Object --
+ -------------------------------------
+
+ function Is_Build_In_Place_Return_Object (E : Entity_Id) return Boolean is
+ begin
+ return Is_Return_Object (E)
+ and then Is_Build_In_Place_Function (Return_Applies_To (Scope (E)));
+ end Is_Build_In_Place_Return_Object;
+
+ -----------------------------------
+ -- Is_By_Reference_Return_Object --
+ -----------------------------------
+
+ function Is_By_Reference_Return_Object (E : Entity_Id) return Boolean is
+ begin
+ return Is_Return_Object (E)
+ and then Is_By_Reference_Type (Etype (Return_Applies_To (Scope (E))));
+ end Is_By_Reference_Return_Object;
+
-----------------------
-- Is_Null_Procedure --
-----------------------
end if;
end Is_Null_Procedure;
+ --------------------------------------
+ -- Is_Secondary_Stack_Return_Object --
+ --------------------------------------
+
+ function Is_Secondary_Stack_Return_Object (E : Entity_Id) return Boolean is
+ begin
+ return Is_Return_Object (E)
+ and then Needs_Secondary_Stack (Etype (Return_Applies_To (Scope (E))));
+ end Is_Secondary_Stack_Return_Object;
+
+ ------------------------------
+ -- Is_Special_Return_Object --
+ ------------------------------
+
+ function Is_Special_Return_Object (E : Entity_Id) return Boolean is
+ begin
+ return Is_Build_In_Place_Return_Object (E)
+ or else Is_Secondary_Stack_Return_Object (E)
+ or else (Back_End_Return_Slot
+ and then Is_By_Reference_Return_Object (E));
+ end Is_Special_Return_Object;
+
-------------------------------------------
-- Make_Build_In_Place_Call_In_Allocator --
-------------------------------------------
-- initialization expression of the object to Empty, which would be
-- illegal Ada, and would cause gigi to misallocate X.
+ Is_OK_Return_Object : constant Boolean :=
+ Is_Return_Object (Obj_Def_Id)
+ and then
+ not Has_Foreign_Convention (Return_Applies_To (Scope (Obj_Def_Id)));
+
-- Start of processing for Make_Build_In_Place_Call_In_Object_Declaration
begin
-- the result object is in a different (transient) scope, so won't cause
-- freezing.
- if Definite and then not Is_Return_Object (Obj_Def_Id) then
+ if Definite and then not Is_OK_Return_Object then
-- The presence of an address clause complicates the build-in-place
-- expansion because the indicated address must be processed before
-- really be directly built in place in the aggregate and not in a
-- temporary. ???)
- if Is_Return_Object (Obj_Def_Id) then
+ if Is_OK_Return_Object then
Pass_Caller_Acc := True;
-- When the enclosing function has a BIP_Alloc_Form formal then we
-- itself the return expression of an enclosing BIP function, then mark
-- the object as having no initialization.
- if Definite and then not Is_Return_Object (Obj_Def_Id) then
+ if Definite and then not Is_OK_Return_Object then
-- The related object declaration is encased in a transient block
-- because the build-in-place function call contains at least one
and then not No_Run_Time_Mode
and then (Has_Task (Typ)
or else (Is_Class_Wide_Type (Typ)
- and then Is_Limited_Record (Typ)
+ and then Is_Limited_Record (Etype (Typ))
and then not Has_Aspect
(Etype (Typ), Aspect_No_Task_Parts)));
end Might_Have_Tasks;
----------------------------
function Needs_BIP_Task_Actuals (Func_Id : Entity_Id) return Boolean is
- pragma Assert (Is_Build_In_Place_Function (Func_Id));
Subp_Id : Entity_Id;
Func_Typ : Entity_Id;
-- formals.
if Is_Thunk (Func_Id) then
- Subp_Id := Thunk_Entity (Func_Id);
+ Subp_Id := Thunk_Target (Func_Id);
-- Common case
Func_Typ := Underlying_Type (Etype (Subp_Id));
+ -- Functions returning types with foreign convention don't have extra
+ -- formals.
+
+ if Has_Foreign_Convention (Func_Typ) then
+ return False;
+
-- At first sight, for all the following cases, we could add assertions
-- to ensure that if Func_Id is frozen then the computed result matches
-- with the availability of the task master extra formal; unfortunately
-- (that is, Is_Frozen has been set by Freeze_Entity but it has not
-- completed its work).
- if Has_Task (Func_Typ) then
+ elsif Has_Task (Func_Typ) then
return True;
elsif Ekind (Func_Id) = E_Function then
-- Needs_BIP_Finalization_Master --
-----------------------------------
- function Needs_BIP_Finalization_Master
- (Func_Id : Entity_Id) return Boolean
+ 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));
+ Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
+
begin
-- A formal giving the finalization master is needed for build-in-place
-- functions whose result type needs finalization or is a tagged type.
-- Tagged primitive build-in-place functions need such a formal because
-- they can be called by a dispatching call, and extensions may require
- -- finalization even if the root type doesn't. This means they're also
- -- needed for tagged nonprimitive build-in-place functions with tagged
- -- results, since such functions can be called via access-to-function
- -- types, and those can be used to call primitives, so masters have to
- -- be passed to all such build-in-place functions, primitive or not.
-
- return
- not Restriction_Active (No_Finalization)
- and then (Needs_Finalization (Func_Typ)
- or else Is_Tagged_Type (Func_Typ));
+ -- finalization even if the root type doesn't. This means nonprimitive
+ -- build-in-place functions with tagged results also need it, since such
+ -- functions can be called via access-to-function types, and those can
+ -- be used to call primitives, so the formal needs to be passed to all
+ -- such build-in-place functions, primitive or not.
+
+ return not Restriction_Active (No_Finalization)
+ and then (Needs_Finalization (Typ) or else Is_Tagged_Type (Typ))
+ and then not Has_Foreign_Convention (Typ);
end Needs_BIP_Finalization_Master;
--------------------------
--------------------------
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));
+ Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id));
+
begin
- return Requires_Transient_Scope (Func_Typ);
+ -- A formal giving the allocation method is needed for build-in-place
+ -- functions whose result type is returned on the secondary stack or
+ -- is a tagged type. Tagged primitive build-in-place functions need
+ -- such a formal because they can be called by a dispatching call, and
+ -- the secondary stack is always used for dispatching-on-result calls.
+ -- This means nonprimitive build-in-place functions with tagged results
+ -- also need it, as such functions can be called via access-to-function
+ -- types, and those can be used to call primitives, so the formal needs
+ -- to be passed to all such build-in-place functions, primitive or not.
+
+ return not Restriction_Active (No_Secondary_Stack)
+ and then (Needs_Secondary_Stack (Typ) or else Is_Tagged_Type (Typ))
+ and then not Has_Foreign_Convention (Typ);
end Needs_BIP_Alloc_Form;
-------------------------------------
return Unqual_BIP_Function_Call (Expr);
end Unqual_BIP_Iface_Function_Call;
+ -------------------------------
+ -- Validate_Subprogram_Calls --
+ -------------------------------
+
+ procedure Validate_Subprogram_Calls (N : Node_Id) is
+
+ function Process_Node (Nod : Node_Id) return Traverse_Result;
+ -- Function to traverse the subtree of N using Traverse_Proc.
+
+ ------------------
+ -- Process_Node --
+ ------------------
+
+ function Process_Node (Nod : Node_Id) return Traverse_Result is
+ begin
+ case Nkind (Nod) is
+ when N_Entry_Call_Statement
+ | N_Procedure_Call_Statement
+ | N_Function_Call
+ =>
+ declare
+ Call_Node : Node_Id renames Nod;
+ Subp : Entity_Id;
+
+ begin
+ -- Call using access to subprogram with explicit dereference
+
+ if Nkind (Name (Call_Node)) = N_Explicit_Dereference then
+ Subp := Etype (Name (Call_Node));
+
+ -- Prefix notation calls
+
+ elsif Nkind (Name (Call_Node)) = N_Selected_Component then
+ Subp := Entity (Selector_Name (Name (Call_Node)));
+
+ -- 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))));
+
+ -- Normal case
+
+ else
+ Subp := Entity (Name (Call_Node));
+ end if;
+
+ pragma Assert (Check_BIP_Actuals (Call_Node, Subp));
+ end;
+
+ -- Skip generic bodies
+
+ when N_Package_Body =>
+ if Ekind (Unique_Defining_Entity (Nod)) = E_Generic_Package then
+ return Skip;
+ end if;
+
+ when N_Subprogram_Body =>
+ if Ekind (Unique_Defining_Entity (Nod)) in E_Generic_Function
+ | E_Generic_Procedure
+ then
+ return Skip;
+ end if;
+
+ -- Nodes we want to ignore
+
+ -- Skip calls placed in the full declaration of record types since
+ -- the call will be performed by their Init Proc; for example,
+ -- calls initializing default values of discriminants or calls
+ -- providing the initial value of record type components. Other
+ -- full type declarations are processed because they may have
+ -- calls that must be checked. For example:
+
+ -- type T is array (1 .. Some_Function_Call (...)) of Some_Type;
+
+ -- ??? More work needed here to handle the following case:
+
+ -- type Rec is record
+ -- F : String (1 .. <some complicated expression>);
+ -- end record;
+
+ when N_Full_Type_Declaration =>
+ if Is_Record_Type (Defining_Entity (Nod)) then
+ return Skip;
+ end if;
+
+ -- Skip calls placed in subprogram specifications since function
+ -- calls initializing default parameter values will be processed
+ -- when the call to the subprogram is found (if the default actual
+ -- parameter is required), and calls found in aspects will be
+ -- processed when their corresponding pragma is found, or in the
+ -- specific case of class-wide pre-/postconditions, when their
+ -- helpers are found.
+
+ when N_Procedure_Specification
+ | N_Function_Specification
+ =>
+ return Skip;
+
+ when N_Abstract_Subprogram_Declaration
+ | N_At_Clause
+ | N_Call_Marker
+ | N_Empty
+ | N_Enumeration_Representation_Clause
+ | N_Enumeration_Type_Definition
+ | N_Function_Instantiation
+ | N_Freeze_Generic_Entity
+ | N_Generic_Function_Renaming_Declaration
+ | N_Generic_Package_Renaming_Declaration
+ | N_Generic_Procedure_Renaming_Declaration
+ | N_Generic_Package_Declaration
+ | N_Generic_Subprogram_Declaration
+ | N_Itype_Reference
+ | N_Number_Declaration
+ | N_Package_Instantiation
+ | N_Package_Renaming_Declaration
+ | N_Pragma
+ | N_Procedure_Instantiation
+ | N_Protected_Type_Declaration
+ | N_Record_Representation_Clause
+ | N_Validate_Unchecked_Conversion
+ | N_Variable_Reference_Marker
+ | N_Use_Package_Clause
+ | N_Use_Type_Clause
+ | N_With_Clause
+ =>
+ return Skip;
+
+ when others =>
+ null;
+ end case;
+
+ return OK;
+ end Process_Node;
+
+ procedure Check_Calls is new Traverse_Proc (Process_Node);
+
+ -- Start of processing for Validate_Subprogram_Calls
+
+ begin
+ -- No action required if we are not generating code or compiling sources
+ -- that have errors.
+
+ if Serious_Errors_Detected > 0
+ or else Operating_Mode /= Generate_Code
+ then
+ return;
+ end if;
+
+ Check_Calls (N);
+ end Validate_Subprogram_Calls;
+
--------------
-- Warn_BIP --
--------------
git://gcc.gnu.org / gcc.git / blobdiff