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-- --
-- --
-- E X P _ C H 1 3 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2021, 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 --
-- 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 Einfo; use Einfo;
with Einfo.Entities; use Einfo.Entities;
with Einfo.Utils; use Einfo.Utils;
with Exp_Ch3; use Exp_Ch3;
with Exp_Ch6;
with Exp_Imgv; use Exp_Imgv;
with Exp_Tss; use Exp_Tss;
with Exp_Util; use Exp_Util;
with Freeze; use Freeze;
with Namet; use Namet;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Aux; use Sem_Aux;
with Sem_Ch7; use Sem_Ch7;
with Sem_Ch8; use Sem_Ch8;
with Sem_Eval; use Sem_Eval;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Sinfo.Nodes; use Sinfo.Nodes;
with Sinfo.Utils; use Sinfo.Utils;
with Snames; use Snames;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Validsw; use Validsw;
package body Exp_Ch13 is
-- Expand_N_Attribute_Definition_Clause --
-- Expansion action depends on attribute involved
procedure Expand_N_Attribute_Definition_Clause (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Exp : constant Node_Id := Expression (N);
Ent : Entity_Id;
V : Node_Id;
Ent := Entity (Name (N));
if Is_Type (Ent) then
Ent := Underlying_Type (Ent);
end if;
case Get_Attribute_Id (Chars (N)) is
-- Address --
when Attribute_Address =>
-- If there is an initialization which did not come from the
-- source program, then it is an artifact of our expansion, and we
-- suppress it. The case we are most concerned about here is the
-- initialization of a packed array to all false, which seems
-- inappropriate for variable to which an address clause is
-- applied. The expression may itself have been rewritten if the
-- type is packed array, so we need to examine whether the
-- original node is in the source. An exception though is the case
-- of an access variable which is default initialized to null, and
-- such initialization is retained.
-- Furthermore, if the initialization is the equivalent aggregate
-- of the type initialization procedure, it replaces an implicit
-- call to the init proc, and must be respected. Note that for
-- packed types we do not build equivalent aggregates.
-- Also, if Init_Or_Norm_Scalars applies, then we need to retain
-- any default initialization for objects of scalar types and
-- types with scalar components. Normally a composite type will
-- have an init_proc in the presence of Init_Or_Norm_Scalars,
-- so when that flag is set we have just have to do a test for
-- scalar and string types (the predefined string types such as
-- String and Wide_String don't have an init_proc).
Decl : constant Node_Id := Declaration_Node (Ent);
Typ : constant Entity_Id := Etype (Ent);
if Nkind (Decl) = N_Object_Declaration
and then Present (Expression (Decl))
and then Nkind (Expression (Decl)) /= N_Null
and then
not Comes_From_Source (Original_Node (Expression (Decl)))
if Present (Base_Init_Proc (Typ))
and then
Present (Static_Initialization (Base_Init_Proc (Typ)))
elsif Init_Or_Norm_Scalars
and then (Is_Scalar_Type (Typ)
or else Is_String_Type (Typ))
Set_Expression (Decl, Empty);
end if;
-- An object declaration to which an address clause applies
-- has a delayed freeze, but the address expression itself
-- must be elaborated at the point it appears. If the object
-- is controlled, additional checks apply elsewhere.
-- If the attribute comes from an aspect specification it
-- is being elaborated at the freeze point and side effects
-- need not be removed (and shouldn't, if the expression
-- depends on other entities that have delayed freeze).
-- This is another consequence of the delayed analysis of
-- aspects, and a real semantic difference.
elsif Nkind (Decl) = N_Object_Declaration
and then not Needs_Constant_Address (Decl, Typ)
and then not From_Aspect_Specification (N)
Remove_Side_Effects (Exp);
end if;
-- Alignment --
when Attribute_Alignment =>
-- As required by Gigi, we guarantee that the operand is an
-- integer literal (this simplifies things in Gigi).
if Nkind (Exp) /= N_Integer_Literal then
Rewrite (Exp, Make_Integer_Literal (Loc, Expr_Value (Exp)));
end if;
-- A complex case arises if the alignment clause applies to an
-- unconstrained object initialized with a function call. The
-- result of the call is placed on the secondary stack, and the
-- declaration is rewritten as a renaming of a dereference, which
-- fails expansion. We must introduce a temporary and assign its
-- value to the existing entity.
if Nkind (Parent (Ent)) = N_Object_Renaming_Declaration
and then not Is_Entity_Name (Renamed_Object (Ent))
Decl : constant Node_Id := Parent (Ent);
Loc : constant Source_Ptr := Sloc (N);
Temp : constant Entity_Id := Make_Temporary (Loc, 'T');
New_Decl : Node_Id;
-- Replace entity with temporary and reanalyze
Set_Defining_Identifier (Decl, Temp);
Set_Analyzed (Decl, False);
Analyze (Decl);
-- Introduce new declaration for entity but do not reanalyze
-- because entity is already in scope. Type and expression
-- are already resolved.
New_Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Ent,
Object_Definition =>
New_Occurrence_Of (Etype (Ent), Loc),
Expression => New_Occurrence_Of (Temp, Loc));
Set_Renamed_Object (Ent, Empty);
Insert_After (Decl, New_Decl);
Set_Analyzed (Decl);
end if;
-- Storage_Size --
when Attribute_Storage_Size =>
-- If the type is a task type, then assign the value of the
-- storage size to the Size variable associated with the task.
-- Insert the assignment right after the declaration of the Size
-- variable.
-- Generate:
-- task_typeZ := expression
if Ekind (Ent) = E_Task_Type then
Assign : Node_Id;
Assign :=
Make_Assignment_Statement (Loc,
Name =>
New_Occurrence_Of (Storage_Size_Variable (Ent), Loc),
Expression =>
Convert_To (RTE (RE_Size_Type), Expression (N)));
-- If the clause is not generated by an aspect, insert
-- the assignment here. Freezing rules ensure that this
-- is safe, or clause will have been rejected already.
if Is_List_Member (N) then
Insert_After (N, Assign);
-- Otherwise, insert assignment after task declaration.
(Parent (Storage_Size_Variable (Entity (N))), Assign);
end if;
Analyze (Assign);
-- For Storage_Size for an access type, create a variable to hold
-- the value of the specified size with name typeV and expand an
-- assignment statement to initialize this value.
elsif Is_Access_Type (Ent) then
-- We don't need the variable for a storage size of zero
if not No_Pool_Assigned (Ent) then
V :=
Make_Defining_Identifier (Loc,
Chars => New_External_Name (Chars (Ent), 'V'));
-- Insert the declaration of the object. If the expression
-- is not static it may depend on some other type that is
-- not frozen yet, so attach the declaration that captures
-- the value of the expression to the actions of the freeze
-- node of the current type.
Decl : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => V,
Object_Definition =>
New_Occurrence_Of (RTE (RE_Storage_Offset), Loc),
Expression =>
(RTE (RE_Storage_Offset), Expression (N)));
if not Is_OK_Static_Expression (Expression (N))
and then Present (Freeze_Node (Ent))
if No (Actions (Freeze_Node (Ent))) then
Set_Actions (Freeze_Node (Ent), New_List (Decl));
Append (Decl, Actions (Freeze_Node (Ent)));
end if;
Insert_Action (N, Decl);
end if;
Set_Storage_Size_Variable (Ent, Entity_Id (V));
end if;
end if;
-- Other attributes require no expansion
when others =>
end case;
end Expand_N_Attribute_Definition_Clause;
-- Expand_N_Free_Statement --
procedure Expand_N_Free_Statement (N : Node_Id) is
Expr : constant Node_Id := Expression (N);
Typ : Entity_Id;
-- Certain run-time configurations and targets do not provide support
-- for controlled types.
if Restriction_Active (No_Finalization) then
end if;
-- Use the base type to perform the check for finalization master
Typ := Etype (Expr);
if Ekind (Typ) = E_Access_Subtype then
Typ := Etype (Typ);
end if;
-- Handle private access types
if Is_Private_Type (Typ)
and then Present (Full_View (Typ))
Typ := Full_View (Typ);
end if;
-- Do not create a custom Deallocate when freeing an object with
-- suppressed finalization. In such cases the object is never attached
-- to a master, so it does not need to be detached. Use a regular free
-- statement instead.
if No (Finalization_Master (Typ)) then
end if;
-- Use a temporary to store the result of a complex expression. Perform
-- the following transformation:
-- Free (Complex_Expression);
-- Temp : constant Type_Of_Expression := Complex_Expression;
-- Free (Temp);
if Nkind (Expr) /= N_Identifier then
Expr_Typ : constant Entity_Id := Etype (Expr);
Loc : constant Source_Ptr := Sloc (N);
New_Expr : Node_Id;
Temp_Id : Entity_Id;
Temp_Id := Make_Temporary (Loc, 'T');
Insert_Action (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Temp_Id,
Object_Definition => New_Occurrence_Of (Expr_Typ, Loc),
Expression => Relocate_Node (Expr)));
New_Expr := New_Occurrence_Of (Temp_Id, Loc);
Set_Etype (New_Expr, Expr_Typ);
Set_Expression (N, New_Expr);
end if;
-- Create a custom Deallocate for a controlled object. This routine
-- ensures that the hidden list header will be deallocated along with
-- the actual object.
Build_Allocate_Deallocate_Proc (N, Is_Allocate => False);
end Expand_N_Free_Statement;
-- Expand_N_Freeze_Entity --
procedure Expand_N_Freeze_Entity (N : Node_Id) is
E : constant Entity_Id := Entity (N);
Decl : Node_Id;
Delete : Boolean := False;
E_Scope : Entity_Id;
In_Other_Scope : Boolean;
In_Outer_Scope : Boolean;
-- If there are delayed aspect specifications, we insert them just
-- before the freeze node. They are already analyzed so we don't need
-- to reanalyze them (they were analyzed before the type was frozen),
-- but we want them in the tree for the back end, and so that the
-- listing from sprint is clearer on where these occur logically.
if Has_Delayed_Aspects (E) then
Aitem : Node_Id;
Ritem : Node_Id;
-- Look for aspect specs for this entity
Ritem := First_Rep_Item (E);
while Present (Ritem) loop
if Nkind (Ritem) = N_Aspect_Specification
and then Entity (Ritem) = E
Aitem := Aspect_Rep_Item (Ritem);
-- Skip this for aspects (e.g. Current_Value) for which
-- there is no corresponding pragma or attribute.
if Present (Aitem)
-- Also skip if we have a null statement rather than a
-- delayed aspect (this happens when we are ignoring rep
-- items from use of the -gnatI switch).
and then Nkind (Aitem) /= N_Null_Statement
pragma Assert (Is_Delayed_Aspect (Aitem));
Insert_Before (N, Aitem);
end if;
end if;
Next_Rep_Item (Ritem);
end loop;
end if;
-- Processing for objects
if Is_Object (E) then
if Present (Address_Clause (E)) then
Apply_Address_Clause_Check (E, N);
end if;
-- Analyze actions in freeze node, if any
if Present (Actions (N)) then
Act : Node_Id;
Act := First (Actions (N));
while Present (Act) loop
Analyze (Act);
Next (Act);
end loop;
end if;
-- If initialization statements have been captured in a compound
-- statement, insert them back into the tree now.
Explode_Initialization_Compound_Statement (E);
-- Only other items requiring any front end action are types and
-- subprograms.
elsif not Is_Type (E) and then not Is_Subprogram (E) then
end if;
-- Here E is a type or a subprogram
E_Scope := Scope (E);
-- This is an error protection against previous errors
if No (E_Scope) then
end if;
-- The entity may be a subtype declared for a constrained record
-- component, in which case the relevant scope is the scope of
-- the record. This happens for class-wide subtypes created for
-- a constrained type extension with inherited discriminants.
if Is_Type (E_Scope)
and then Ekind (E_Scope) not in Concurrent_Kind
E_Scope := Scope (E_Scope);
-- The entity may be a subtype declared for an iterator
elsif Ekind (E_Scope) = E_Loop then
E_Scope := Scope (E_Scope);
end if;
-- Remember that we are processing a freezing entity and its freezing
-- nodes. This flag (non-zero = set) is used to avoid the need of
-- climbing through the tree while processing the freezing actions (ie.
-- to avoid generating spurious warnings or to avoid killing constant
-- indications while processing the code associated with freezing
-- actions). We use a counter to deal with nesting.
Inside_Freezing_Actions := Inside_Freezing_Actions + 1;
-- If we are freezing entities defined in protected types, they belong
-- in the enclosing scope, given that the original type has been
-- expanded away. The same is true for entities in task types, in
-- particular the parameter records of entries (Entities in bodies are
-- all frozen within the body). If we are in the task body, this is a
-- proper scope. If we are within a subprogram body, the proper scope
-- is the corresponding spec. This may happen for itypes generated in
-- the bodies of protected operations.
if Ekind (E_Scope) = E_Protected_Type
or else (Ekind (E_Scope) = E_Task_Type
and then not Has_Completion (E_Scope))
E_Scope := Scope (E_Scope);
elsif Ekind (E_Scope) = E_Subprogram_Body then
E_Scope := Corresponding_Spec (Unit_Declaration_Node (E_Scope));
end if;
-- If the scope of the entity is in open scopes, it is the current one
-- or an enclosing one, including a loop, a block, or a subprogram.
if In_Open_Scopes (E_Scope) then
In_Other_Scope := False;
In_Outer_Scope := E_Scope /= Current_Scope;
-- Otherwise it is a local package or a different compilation unit
In_Other_Scope := True;
In_Outer_Scope := False;
end if;
-- If the entity being frozen is defined in a scope that is not
-- currently on the scope stack, we must establish the proper
-- visibility before freezing the entity and related subprograms.
if In_Other_Scope then
Push_Scope (E_Scope);
-- Finalizers are little odd in terms of freezing. The spec of the
-- procedure appears in the declarations while the body appears in
-- the statement part of a single construct. Since the finalizer must
-- be called by the At_End handler of the construct, the spec is
-- manually frozen right after its declaration. The only side effect
-- of this action appears in contexts where the construct is not in
-- its final resting place. These contexts are:
-- * Entry bodies - The declarations and statements are moved to
-- the procedure equivalen of the entry.
-- * Protected subprograms - The declarations and statements are
-- moved to the non-protected version of the subprogram.
-- * Task bodies - The declarations and statements are moved to the
-- task body procedure.
-- * Blocks that will be rewritten as subprograms when unnesting
-- is in effect.
-- Visible declarations do not need to be installed in these three
-- cases since it does not make semantic sense to do so. All entities
-- referenced by a finalizer are visible and already resolved, plus
-- the enclosing scope may not have visible declarations at all.
if Ekind (E) = E_Procedure
and then Is_Finalizer (E)
and then
(Is_Entry (E_Scope)
or else (Is_Subprogram (E_Scope)
and then Is_Protected_Type (Scope (E_Scope)))
or else Is_Task_Type (E_Scope)
or else Ekind (E_Scope) = E_Block)
Install_Visible_Declarations (E_Scope);
end if;
if Is_Concurrent_Type (E_Scope)
or else Is_Package_Or_Generic_Package (E_Scope)
Install_Private_Declarations (E_Scope);
end if;
-- If the entity is in an outer scope, then that scope needs to
-- temporarily become the current scope so that operations created
-- during type freezing will be declared in the right scope and
-- can properly override any corresponding inherited operations.
elsif In_Outer_Scope then
Push_Scope (E_Scope);
end if;
-- If type, freeze the type
if Is_Type (E) then
Delete := Freeze_Type (N);
-- And for enumeration type, build the enumeration tables
if Is_Enumeration_Type (E) then
Build_Enumeration_Image_Tables (E, N);
end if;
-- If subprogram, freeze the subprogram
elsif Is_Subprogram (E) then
Exp_Ch6.Freeze_Subprogram (N);
-- Ada 2005 (AI-251): Remove the freezing node associated with the
-- entities internally used by the frontend to register primitives
-- covering abstract interfaces. The call to Freeze_Subprogram has
-- already expanded the code that fills the corresponding entry in
-- its secondary dispatch table and therefore the code generator
-- has nothing else to do with this freezing node.
Delete := Present (Interface_Alias (E));
end if;
-- Analyze actions generated by freezing. The init_proc contains source
-- expressions that may raise Constraint_Error, and the assignment
-- procedure for complex types needs checks on individual component
-- assignments, but all other freezing actions should be compiled with
-- all checks off.
if Present (Actions (N)) then
Decl := First (Actions (N));
while Present (Decl) loop
if Nkind (Decl) = N_Subprogram_Body
and then (Is_Init_Proc (Defining_Entity (Decl))
or else
Chars (Defining_Entity (Decl)) = Name_uAssign)
Analyze (Decl);
-- A subprogram body created for a renaming_as_body completes
-- a previous declaration, which may be in a different scope.
-- Establish the proper scope before analysis.
elsif Nkind (Decl) = N_Subprogram_Body
and then Present (Corresponding_Spec (Decl))
and then Scope (Corresponding_Spec (Decl)) /= Current_Scope
Push_Scope (Scope (Corresponding_Spec (Decl)));
Analyze (Decl, Suppress => All_Checks);
-- We treat generated equality specially, if validity checks are
-- enabled, in order to detect components default-initialized
-- with invalid values.
elsif Nkind (Decl) = N_Subprogram_Body
and then Chars (Defining_Entity (Decl)) = Name_Op_Eq
and then Validity_Checks_On
and then Initialize_Scalars
Save_Force : constant Boolean := Force_Validity_Checks;
Force_Validity_Checks := True;
Analyze (Decl);
Force_Validity_Checks := Save_Force;
-- All other freezing actions
Analyze (Decl, Suppress => All_Checks);
end if;
Next (Decl);
end loop;
end if;
-- If we are to delete this N_Freeze_Entity, do so by rewriting so that
-- a loop on all nodes being inserted will work propertly.
if Delete then
Rewrite (N, Make_Null_Statement (Sloc (N)));
end if;
-- Pop scope if we installed one for the analysis
if In_Other_Scope then
if Ekind (Current_Scope) = E_Package then
End_Package_Scope (E_Scope);
end if;
elsif In_Outer_Scope then
end if;
-- Restore previous value of the nesting-level counter that records
-- whether we are inside a (possibly nested) call to this procedure.
Inside_Freezing_Actions := Inside_Freezing_Actions - 1;
end Expand_N_Freeze_Entity;
-- Expand_N_Record_Representation_Clause --
-- The only expansion required is for the case of a mod clause present,
-- which is removed, and translated into an alignment representation
-- clause inserted immediately after the record rep clause with any
-- initial pragmas inserted at the start of the component clause list.
procedure Expand_N_Record_Representation_Clause (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Rectype : constant Entity_Id := Entity (Identifier (N));
Mod_Val : Uint;
Citems : List_Id;
Repitem : Node_Id;
AtM_Nod : Node_Id;
if Present (Mod_Clause (N)) and then not Ignore_Rep_Clauses then
Mod_Val := Expr_Value (Expression (Mod_Clause (N)));
Citems := Pragmas_Before (Mod_Clause (N));
if Present (Citems) then
Append_List_To (Citems, Component_Clauses (N));
Set_Component_Clauses (N, Citems);
end if;
AtM_Nod :=
Make_Attribute_Definition_Clause (Loc,
Name => New_Occurrence_Of (Base_Type (Rectype), Loc),
Chars => Name_Alignment,
Expression => Make_Integer_Literal (Loc, Mod_Val));
Set_From_At_Mod (AtM_Nod);
Insert_After (N, AtM_Nod);
Set_Mod_Clause (N, Empty);
end if;
-- If the record representation clause has no components, then
-- completely remove it. Note that we also have to remove
-- ourself from the Rep Item list.
if Is_Empty_List (Component_Clauses (N)) then
if First_Rep_Item (Rectype) = N then
Set_First_Rep_Item (Rectype, Next_Rep_Item (N));
Repitem := First_Rep_Item (Rectype);
while Present (Next_Rep_Item (Repitem)) loop
if Next_Rep_Item (Repitem) = N then
Set_Next_Rep_Item (Repitem, Next_Rep_Item (N));
end if;
Next_Rep_Item (Repitem);
end loop;
end if;
Rewrite (N,
Make_Null_Statement (Loc));
end if;
end Expand_N_Record_Representation_Clause;
end Exp_Ch13;