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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- E X P _ A G G R --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Atree; use Atree;
with Checks; use Checks;
with Debug; use Debug;
with Einfo; use Einfo;
with Elists; use Elists;
with Errout; use Errout;
with Expander; use Expander;
with Exp_Util; use Exp_Util;
with Exp_Ch3; use Exp_Ch3;
with Exp_Ch6; use Exp_Ch6;
with Exp_Ch7; use Exp_Ch7;
with Exp_Ch9; use Exp_Ch9;
with Exp_Disp; use Exp_Disp;
with Exp_Tss; use Exp_Tss;
with Fname; use Fname;
with Freeze; use Freeze;
with Itypes; use Itypes;
with Lib; use Lib;
with Namet; use Namet;
with Nmake; use Nmake;
with Nlists; use Nlists;
with Opt; use Opt;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Ttypes; use Ttypes;
with Sem; use Sem;
with Sem_Aggr; use Sem_Aggr;
with Sem_Aux; use Sem_Aux;
with Sem_Ch3; use Sem_Ch3;
with Sem_Eval; use Sem_Eval;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Snames; use Snames;
with Stand; use Stand;
with Targparm; use Targparm;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
package body Exp_Aggr is
type Case_Bounds is record
Choice_Lo : Node_Id;
Choice_Hi : Node_Id;
Choice_Node : Node_Id;
end record;
type Case_Table_Type is array (Nat range <>) of Case_Bounds;
-- Table type used by Check_Case_Choices procedure
function Has_Default_Init_Comps (N : Node_Id) return Boolean;
-- N is an aggregate (record or array). Checks the presence of default
-- initialization (<>) in any component (Ada 2005: AI-287).
function Is_Static_Dispatch_Table_Aggregate (N : Node_Id) return Boolean;
-- Returns true if N is an aggregate used to initialize the components
-- of an statically allocated dispatch table.
function Must_Slide
(Obj_Type : Entity_Id;
Typ : Entity_Id) return Boolean;
-- A static array aggregate in an object declaration can in most cases be
-- expanded in place. The one exception is when the aggregate is given
-- with component associations that specify different bounds from those of
-- the type definition in the object declaration. In this pathological
-- case the aggregate must slide, and we must introduce an intermediate
-- temporary to hold it.
--
-- The same holds in an assignment to one-dimensional array of arrays,
-- when a component may be given with bounds that differ from those of the
-- component type.
procedure Sort_Case_Table (Case_Table : in out Case_Table_Type);
-- Sort the Case Table using the Lower Bound of each Choice as the key.
-- A simple insertion sort is used since the number of choices in a case
-- statement of variant part will usually be small and probably in near
-- sorted order.
procedure Collect_Initialization_Statements
(Obj : Entity_Id;
N : Node_Id;
Node_After : Node_Id);
-- If Obj is not frozen, collect actions inserted after N until, but not
-- including, Node_After, for initialization of Obj, and move them to an
-- expression with actions, which becomes the Initialization_Statements for
-- Obj.
------------------------------------------------------
-- Local subprograms for Record Aggregate Expansion --
------------------------------------------------------
function Build_Record_Aggr_Code
(N : Node_Id;
Typ : Entity_Id;
Lhs : Node_Id) return List_Id;
-- N is an N_Aggregate or an N_Extension_Aggregate. Typ is the type of the
-- aggregate. Target is an expression containing the location on which the
-- component by component assignments will take place. Returns the list of
-- assignments plus all other adjustments needed for tagged and controlled
-- types.
procedure Convert_To_Assignments (N : Node_Id; Typ : Entity_Id);
-- N is an N_Aggregate or an N_Extension_Aggregate. Typ is the type of the
-- aggregate (which can only be a record type, this procedure is only used
-- for record types). Transform the given aggregate into a sequence of
-- assignments performed component by component.
procedure Expand_Record_Aggregate
(N : Node_Id;
Orig_Tag : Node_Id := Empty;
Parent_Expr : Node_Id := Empty);
-- This is the top level procedure for record aggregate expansion.
-- Expansion for record aggregates needs expand aggregates for tagged
-- record types. Specifically Expand_Record_Aggregate adds the Tag
-- field in front of the Component_Association list that was created
-- during resolution by Resolve_Record_Aggregate.
--
-- N is the record aggregate node.
-- Orig_Tag is the value of the Tag that has to be provided for this
-- specific aggregate. It carries the tag corresponding to the type
-- of the outermost aggregate during the recursive expansion
-- Parent_Expr is the ancestor part of the original extension
-- aggregate
function Has_Mutable_Components (Typ : Entity_Id) return Boolean;
-- Return true if one of the component is of a discriminated type with
-- defaults. An aggregate for a type with mutable components must be
-- expanded into individual assignments.
procedure Initialize_Discriminants (N : Node_Id; Typ : Entity_Id);
-- If the type of the aggregate is a type extension with renamed discrimi-
-- nants, we must initialize the hidden discriminants of the parent.
-- Otherwise, the target object must not be initialized. The discriminants
-- are initialized by calling the initialization procedure for the type.
-- This is incorrect if the initialization of other components has any
-- side effects. We restrict this call to the case where the parent type
-- has a variant part, because this is the only case where the hidden
-- discriminants are accessed, namely when calling discriminant checking
-- functions of the parent type, and when applying a stream attribute to
-- an object of the derived type.
-----------------------------------------------------
-- Local Subprograms for Array Aggregate Expansion --
-----------------------------------------------------
function Aggr_Size_OK (N : Node_Id; Typ : Entity_Id) return Boolean;
-- Very large static aggregates present problems to the back-end, and are
-- transformed into assignments and loops. This function verifies that the
-- total number of components of an aggregate is acceptable for rewriting
-- into a purely positional static form. Aggr_Size_OK must be called before
-- calling Flatten.
--
-- This function also detects and warns about one-component aggregates that
-- appear in a non-static context. Even if the component value is static,
-- such an aggregate must be expanded into an assignment.
function Backend_Processing_Possible (N : Node_Id) return Boolean;
-- This function checks if array aggregate N can be processed directly
-- by the backend. If this is the case True is returned.
function Build_Array_Aggr_Code
(N : Node_Id;
Ctype : Entity_Id;
Index : Node_Id;
Into : Node_Id;
Scalar_Comp : Boolean;
Indexes : List_Id := No_List) return List_Id;
-- This recursive routine returns a list of statements containing the
-- loops and assignments that are needed for the expansion of the array
-- aggregate N.
--
-- N is the (sub-)aggregate node to be expanded into code. This node has
-- been fully analyzed, and its Etype is properly set.
--
-- Index is the index node corresponding to the array sub-aggregate N
--
-- Into is the target expression into which we are copying the aggregate.
-- Note that this node may not have been analyzed yet, and so the Etype
-- field may not be set.
--
-- Scalar_Comp is True if the component type of the aggregate is scalar
--
-- Indexes is the current list of expressions used to index the object we
-- are writing into.
procedure Convert_Array_Aggr_In_Allocator
(Decl : Node_Id;
Aggr : Node_Id;
Target : Node_Id);
-- If the aggregate appears within an allocator and can be expanded in
-- place, this routine generates the individual assignments to components
-- of the designated object. This is an optimization over the general
-- case, where a temporary is first created on the stack and then used to
-- construct the allocated object on the heap.
procedure Convert_To_Positional
(N : Node_Id;
Max_Others_Replicate : Nat := 5;
Handle_Bit_Packed : Boolean := False);
-- If possible, convert named notation to positional notation. This
-- conversion is possible only in some static cases. If the conversion is
-- possible, then N is rewritten with the analyzed converted aggregate.
-- The parameter Max_Others_Replicate controls the maximum number of
-- values corresponding to an others choice that will be converted to
-- positional notation (the default of 5 is the normal limit, and reflects
-- the fact that normally the loop is better than a lot of separate
-- assignments). Note that this limit gets overridden in any case if
-- either of the restrictions No_Elaboration_Code or No_Implicit_Loops is
-- set. The parameter Handle_Bit_Packed is usually set False (since we do
-- not expect the back end to handle bit packed arrays, so the normal case
-- of conversion is pointless), but in the special case of a call from
-- Packed_Array_Aggregate_Handled, we set this parameter to True, since
-- these are cases we handle in there.
-- It would seem worthwhile to have a higher default value for Max_Others_
-- replicate, but aggregates in the compiler make this impossible: the
-- compiler bootstrap fails if Max_Others_Replicate is greater than 25.
-- This is unexpected ???
procedure Expand_Array_Aggregate (N : Node_Id);
-- This is the top-level routine to perform array aggregate expansion.
-- N is the N_Aggregate node to be expanded.
function Is_Two_Dim_Packed_Array (Typ : Entity_Id) return Boolean;
-- For two-dimensional packed aggregates with constant bounds and constant
-- components, it is preferable to pack the inner aggregates because the
-- whole matrix can then be presented to the back-end as a one-dimensional
-- list of literals. This is much more efficient than expanding into single
-- component assignments. This function determines if the type Typ is for
-- an array that is suitable for this optimization: it returns True if Typ
-- is a two dimensional bit packed array with component size 1, 2, or 4.
function Late_Expansion
(N : Node_Id;
Typ : Entity_Id;
Target : Node_Id) return List_Id;
-- This routine implements top-down expansion of nested aggregates. In
-- doing so, it avoids the generation of temporaries at each level. N is
-- a nested record or array aggregate with the Expansion_Delayed flag.
-- Typ is the expected type of the aggregate. Target is a (duplicatable)
-- expression that will hold the result of the aggregate expansion.
function Make_OK_Assignment_Statement
(Sloc : Source_Ptr;
Name : Node_Id;
Expression : Node_Id) return Node_Id;
-- This is like Make_Assignment_Statement, except that Assignment_OK
-- is set in the left operand. All assignments built by this unit use
-- this routine. This is needed to deal with assignments to initialized
-- constants that are done in place.
function Number_Of_Choices (N : Node_Id) return Nat;
-- Returns the number of discrete choices (not including the others choice
-- if present) contained in (sub-)aggregate N.
function Packed_Array_Aggregate_Handled (N : Node_Id) return Boolean;
-- Given an array aggregate, this function handles the case of a packed
-- array aggregate with all constant values, where the aggregate can be
-- evaluated at compile time. If this is possible, then N is rewritten
-- to be its proper compile time value with all the components properly
-- assembled. The expression is analyzed and resolved and True is returned.
-- If this transformation is not possible, N is unchanged and False is
-- returned.
function Safe_Slice_Assignment (N : Node_Id) return Boolean;
-- If a slice assignment has an aggregate with a single others_choice,
-- the assignment can be done in place even if bounds are not static,
-- by converting it into a loop over the discrete range of the slice.
function Two_Dim_Packed_Array_Handled (N : Node_Id) return Boolean;
-- If the type of the aggregate is a two-dimensional bit_packed array
-- it may be transformed into an array of bytes with constant values,
-- and presented to the back-end as a static value. The function returns
-- false if this transformation cannot be performed. THis is similar to,
-- and reuses part of the machinery in Packed_Array_Aggregate_Handled.
------------------
-- Aggr_Size_OK --
------------------
function Aggr_Size_OK (N : Node_Id; Typ : Entity_Id) return Boolean is
Lo : Node_Id;
Hi : Node_Id;
Indx : Node_Id;
Siz : Int;
Lov : Uint;
Hiv : Uint;
-- The following constant determines the maximum size of an array
-- aggregate produced by converting named to positional notation (e.g.
-- from others clauses). This avoids running away with attempts to
-- convert huge aggregates, which hit memory limits in the backend.
-- The normal limit is 5000, but we increase this limit to 2**24 (about
-- 16 million) if Restrictions (No_Elaboration_Code) or Restrictions
-- (No_Implicit_Loops) is specified, since in either case we are at
-- risk of declaring the program illegal because of this limit. We also
-- increase the limit when Static_Elaboration_Desired, given that this
-- means that objects are intended to be placed in data memory.
-- We also increase the limit if the aggregate is for a packed two-
-- dimensional array, because if components are static it is much more
-- efficient to construct a one-dimensional equivalent array with static
-- components.
Max_Aggr_Size : constant Nat :=
5000 + (2 ** 24 - 5000) *
Boolean'Pos
(Restriction_Active (No_Elaboration_Code)
or else Restriction_Active (No_Implicit_Loops)
or else Is_Two_Dim_Packed_Array (Typ)
or else ((Ekind (Current_Scope) = E_Package
and then Static_Elaboration_Desired (Current_Scope))));
function Component_Count (T : Entity_Id) return Int;
-- The limit is applied to the total number of components that the
-- aggregate will have, which is the number of static expressions
-- that will appear in the flattened array. This requires a recursive
-- computation of the number of scalar components of the structure.
---------------------
-- Component_Count --
---------------------
function Component_Count (T : Entity_Id) return Int is
Res : Int := 0;
Comp : Entity_Id;
begin
if Is_Scalar_Type (T) then
return 1;
elsif Is_Record_Type (T) then
Comp := First_Component (T);
while Present (Comp) loop
Res := Res + Component_Count (Etype (Comp));
Next_Component (Comp);
end loop;
return Res;
elsif Is_Array_Type (T) then
declare
Lo : constant Node_Id :=
Type_Low_Bound (Etype (First_Index (T)));
Hi : constant Node_Id :=
Type_High_Bound (Etype (First_Index (T)));
Siz : constant Int := Component_Count (Component_Type (T));
begin
if not Compile_Time_Known_Value (Lo)
or else not Compile_Time_Known_Value (Hi)
then
return 0;
else
return
Siz * UI_To_Int (Expr_Value (Hi) - Expr_Value (Lo) + 1);
end if;
end;
else
-- Can only be a null for an access type
return 1;
end if;
end Component_Count;
-- Start of processing for Aggr_Size_OK
begin
Siz := Component_Count (Component_Type (Typ));
Indx := First_Index (Typ);
while Present (Indx) loop
Lo := Type_Low_Bound (Etype (Indx));
Hi := Type_High_Bound (Etype (Indx));
-- Bounds need to be known at compile time
if not Compile_Time_Known_Value (Lo)
or else not Compile_Time_Known_Value (Hi)
then
return False;
end if;
Lov := Expr_Value (Lo);
Hiv := Expr_Value (Hi);
-- A flat array is always safe
if Hiv < Lov then
return True;
end if;
-- One-component aggregates are suspicious, and if the context type
-- is an object declaration with non-static bounds it will trip gcc;
-- such an aggregate must be expanded into a single assignment.
if Hiv = Lov
and then Nkind (Parent (N)) = N_Object_Declaration
then
declare
Index_Type : constant Entity_Id :=
Etype
(First_Index (Etype (Defining_Identifier (Parent (N)))));
Indx : Node_Id;
begin
if not Compile_Time_Known_Value (Type_Low_Bound (Index_Type))
or else not Compile_Time_Known_Value
(Type_High_Bound (Index_Type))
then
if Present (Component_Associations (N)) then
Indx :=
First (Choices (First (Component_Associations (N))));
if Is_Entity_Name (Indx)
and then not Is_Type (Entity (Indx))
then
Error_Msg_N
("single component aggregate in "
& "non-static context??", Indx);
Error_Msg_N ("\maybe subtype name was meant??", Indx);
end if;
end if;
return False;
end if;
end;
end if;
declare
Rng : constant Uint := Hiv - Lov + 1;
begin
-- Check if size is too large
if not UI_Is_In_Int_Range (Rng) then
return False;
end if;
Siz := Siz * UI_To_Int (Rng);
end;
if Siz <= 0
or else Siz > Max_Aggr_Size
then
return False;
end if;
-- Bounds must be in integer range, for later array construction
if not UI_Is_In_Int_Range (Lov)
or else
not UI_Is_In_Int_Range (Hiv)
then
return False;
end if;
Next_Index (Indx);
end loop;
return True;
end Aggr_Size_OK;
---------------------------------
-- Backend_Processing_Possible --
---------------------------------
-- Backend processing by Gigi/gcc is possible only if all the following
-- conditions are met:
-- 1. N is fully positional
-- 2. N is not a bit-packed array aggregate;
-- 3. The size of N's array type must be known at compile time. Note
-- that this implies that the component size is also known
-- 4. The array type of N does not follow the Fortran layout convention
-- or if it does it must be 1 dimensional.
-- 5. The array component type may not be tagged (which could necessitate
-- reassignment of proper tags).
-- 6. The array component type must not have unaligned bit components
-- 7. None of the components of the aggregate may be bit unaligned
-- components.
-- 8. There cannot be delayed components, since we do not know enough
-- at this stage to know if back end processing is possible.
-- 9. There cannot be any discriminated record components, since the
-- back end cannot handle this complex case.
-- 10. No controlled actions need to be generated for components
-- 11. For a VM back end, the array should have no aliased components
function Backend_Processing_Possible (N : Node_Id) return Boolean is
Typ : constant Entity_Id := Etype (N);
-- Typ is the correct constrained array subtype of the aggregate
function Component_Check (N : Node_Id; Index : Node_Id) return Boolean;
-- This routine checks components of aggregate N, enforcing checks
-- 1, 7, 8, and 9. In the multi-dimensional case, these checks are
-- performed on subaggregates. The Index value is the current index
-- being checked in the multi-dimensional case.
---------------------
-- Component_Check --
---------------------
function Component_Check (N : Node_Id; Index : Node_Id) return Boolean is
Expr : Node_Id;
begin
-- Checks 1: (no component associations)
if Present (Component_Associations (N)) then
return False;
end if;
-- Checks on components
-- Recurse to check subaggregates, which may appear in qualified
-- expressions. If delayed, the front-end will have to expand.
-- If the component is a discriminated record, treat as non-static,
-- as the back-end cannot handle this properly.
Expr := First (Expressions (N));
while Present (Expr) loop
-- Checks 8: (no delayed components)
if Is_Delayed_Aggregate (Expr) then
return False;
end if;
-- Checks 9: (no discriminated records)
if Present (Etype (Expr))
and then Is_Record_Type (Etype (Expr))
and then Has_Discriminants (Etype (Expr))
then
return False;
end if;
-- Checks 7. Component must not be bit aligned component
if Possible_Bit_Aligned_Component (Expr) then
return False;
end if;
-- Recursion to following indexes for multiple dimension case
if Present (Next_Index (Index))
and then not Component_Check (Expr, Next_Index (Index))
then
return False;
end if;
-- All checks for that component finished, on to next
Next (Expr);
end loop;
return True;
end Component_Check;
-- Start of processing for Backend_Processing_Possible
begin
-- Checks 2 (array not bit packed) and 10 (no controlled actions)
if Is_Bit_Packed_Array (Typ) or else Needs_Finalization (Typ) then
return False;
end if;
-- If component is limited, aggregate must be expanded because each
-- component assignment must be built in place.
if Is_Immutably_Limited_Type (Component_Type (Typ)) then
return False;
end if;
-- Checks 4 (array must not be multi-dimensional Fortran case)
if Convention (Typ) = Convention_Fortran
and then Number_Dimensions (Typ) > 1
then
return False;
end if;
-- Checks 3 (size of array must be known at compile time)
if not Size_Known_At_Compile_Time (Typ) then
return False;
end if;
-- Checks on components
if not Component_Check (N, First_Index (Typ)) then
return False;
end if;
-- Checks 5 (if the component type is tagged, then we may need to do
-- tag adjustments. Perhaps this should be refined to check for any
-- component associations that actually need tag adjustment, similar
-- to the test in Component_Not_OK_For_Backend for record aggregates
-- with tagged components, but not clear whether it's worthwhile ???;
-- in the case of the JVM, object tags are handled implicitly)
if Is_Tagged_Type (Component_Type (Typ))
and then Tagged_Type_Expansion
then
return False;
end if;
-- Checks 6 (component type must not have bit aligned components)
if Type_May_Have_Bit_Aligned_Components (Component_Type (Typ)) then
return False;
end if;
-- Checks 11: Array aggregates with aliased components are currently
-- not well supported by the VM backend; disable temporarily this
-- backend processing until it is definitely supported.
if VM_Target /= No_VM
and then Has_Aliased_Components (Base_Type (Typ))
then
return False;
end if;
-- Backend processing is possible
Set_Size_Known_At_Compile_Time (Etype (N), True);
return True;
end Backend_Processing_Possible;
---------------------------
-- Build_Array_Aggr_Code --
---------------------------
-- The code that we generate from a one dimensional aggregate is
-- 1. If the sub-aggregate contains discrete choices we
-- (a) Sort the discrete choices
-- (b) Otherwise for each discrete choice that specifies a range we
-- emit a loop. If a range specifies a maximum of three values, or
-- we are dealing with an expression we emit a sequence of
-- assignments instead of a loop.
-- (c) Generate the remaining loops to cover the others choice if any
-- 2. If the aggregate contains positional elements we
-- (a) translate the positional elements in a series of assignments
-- (b) Generate a final loop to cover the others choice if any.
-- Note that this final loop has to be a while loop since the case
-- L : Integer := Integer'Last;
-- H : Integer := Integer'Last;
-- A : array (L .. H) := (1, others =>0);
-- cannot be handled by a for loop. Thus for the following
-- array (L .. H) := (.. positional elements.., others =>E);
-- we always generate something like:
-- J : Index_Type := Index_Of_Last_Positional_Element;
-- while J < H loop
-- J := Index_Base'Succ (J)
-- Tmp (J) := E;
-- end loop;
function Build_Array_Aggr_Code
(N : Node_Id;
Ctype : Entity_Id;
Index : Node_Id;
Into : Node_Id;
Scalar_Comp : Boolean;
Indexes : List_Id := No_List) return List_Id
is
Loc : constant Source_Ptr := Sloc (N);
Index_Base : constant Entity_Id := Base_Type (Etype (Index));
Index_Base_L : constant Node_Id := Type_Low_Bound (Index_Base);
Index_Base_H : constant Node_Id := Type_High_Bound (Index_Base);
function Add (Val : Int; To : Node_Id) return Node_Id;
-- Returns an expression where Val is added to expression To, unless
-- To+Val is provably out of To's base type range. To must be an
-- already analyzed expression.
function Empty_Range (L, H : Node_Id) return Boolean;
-- Returns True if the range defined by L .. H is certainly empty
function Equal (L, H : Node_Id) return Boolean;
-- Returns True if L = H for sure
function Index_Base_Name return Node_Id;
-- Returns a new reference to the index type name
function Gen_Assign (Ind : Node_Id; Expr : Node_Id) return List_Id;
-- Ind must be a side-effect free expression. If the input aggregate
-- N to Build_Loop contains no sub-aggregates, then this function
-- returns the assignment statement:
--
-- Into (Indexes, Ind) := Expr;
--
-- Otherwise we call Build_Code recursively
--
-- Ada 2005 (AI-287): In case of default initialized component, Expr
-- is empty and we generate a call to the corresponding IP subprogram.
function Gen_Loop (L, H : Node_Id; Expr : Node_Id) return List_Id;
-- Nodes L and H must be side-effect free expressions.
-- If the input aggregate N to Build_Loop contains no sub-aggregates,
-- This routine returns the for loop statement
--
-- for J in Index_Base'(L) .. Index_Base'(H) loop
-- Into (Indexes, J) := Expr;
-- end loop;
--
-- Otherwise we call Build_Code recursively.
-- As an optimization if the loop covers 3 or less scalar elements we
-- generate a sequence of assignments.
function Gen_While (L, H : Node_Id; Expr : Node_Id) return List_Id;
-- Nodes L and H must be side-effect free expressions.
-- If the input aggregate N to Build_Loop contains no sub-aggregates,
-- This routine returns the while loop statement
--
-- J : Index_Base := L;
-- while J < H loop
-- J := Index_Base'Succ (J);
-- Into (Indexes, J) := Expr;
-- end loop;
--
-- Otherwise we call Build_Code recursively
function Local_Compile_Time_Known_Value (E : Node_Id) return Boolean;
function Local_Expr_Value (E : Node_Id) return Uint;
-- These two Local routines are used to replace the corresponding ones
-- in sem_eval because while processing the bounds of an aggregate with
-- discrete choices whose index type is an enumeration, we build static
-- expressions not recognized by Compile_Time_Known_Value as such since
-- they have not yet been analyzed and resolved. All the expressions in
-- question are things like Index_Base_Name'Val (Const) which we can
-- easily recognize as being constant.
---------
-- Add --
---------
function Add (Val : Int; To : Node_Id) return Node_Id is
Expr_Pos : Node_Id;
Expr : Node_Id;
To_Pos : Node_Id;
U_To : Uint;
U_Val : constant Uint := UI_From_Int (Val);
begin
-- Note: do not try to optimize the case of Val = 0, because
-- we need to build a new node with the proper Sloc value anyway.
-- First test if we can do constant folding
if Local_Compile_Time_Known_Value (To) then
U_To := Local_Expr_Value (To) + Val;
-- Determine if our constant is outside the range of the index.
-- If so return an Empty node. This empty node will be caught
-- by Empty_Range below.
if Compile_Time_Known_Value (Index_Base_L)
and then U_To < Expr_Value (Index_Base_L)
then
return Empty;
elsif Compile_Time_Known_Value (Index_Base_H)
and then U_To > Expr_Value (Index_Base_H)
then
return Empty;
end if;
Expr_Pos := Make_Integer_Literal (Loc, U_To);
Set_Is_Static_Expression (Expr_Pos);
if not Is_Enumeration_Type (Index_Base) then
Expr := Expr_Pos;
-- If we are dealing with enumeration return
-- Index_Base'Val (Expr_Pos)
else
Expr :=
Make_Attribute_Reference
(Loc,
Prefix => Index_Base_Name,
Attribute_Name => Name_Val,
Expressions => New_List (Expr_Pos));
end if;
return Expr;
end if;
-- If we are here no constant folding possible
if not Is_Enumeration_Type (Index_Base) then
Expr :=
Make_Op_Add (Loc,
Left_Opnd => Duplicate_Subexpr (To),
Right_Opnd => Make_Integer_Literal (Loc, U_Val));
-- If we are dealing with enumeration return
-- Index_Base'Val (Index_Base'Pos (To) + Val)
else
To_Pos :=
Make_Attribute_Reference
(Loc,
Prefix => Index_Base_Name,
Attribute_Name => Name_Pos,
Expressions => New_List (Duplicate_Subexpr (To)));
Expr_Pos :=
Make_Op_Add (Loc,
Left_Opnd => To_Pos,
Right_Opnd => Make_Integer_Literal (Loc, U_Val));
Expr :=
Make_Attribute_Reference
(Loc,
Prefix => Index_Base_Name,
Attribute_Name => Name_Val,
Expressions => New_List (Expr_Pos));
end if;
return Expr;
end Add;
-----------------
-- Empty_Range --
-----------------
function Empty_Range (L, H : Node_Id) return Boolean is
Is_Empty : Boolean := False;
Low : Node_Id;
High : Node_Id;
begin
-- First check if L or H were already detected as overflowing the
-- index base range type by function Add above. If this is so Add
-- returns the empty node.
if No (L) or else No (H) then
return True;
end if;
for J in 1 .. 3 loop
case J is
-- L > H range is empty
when 1 =>
Low := L;
High := H;
-- B_L > H range must be empty
when 2 =>
Low := Index_Base_L;
High := H;
-- L > B_H range must be empty
when 3 =>
Low := L;
High := Index_Base_H;
end case;
if Local_Compile_Time_Known_Value (Low)
and then Local_Compile_Time_Known_Value (High)
then
Is_Empty :=
UI_Gt (Local_Expr_Value (Low), Local_Expr_Value (High));
end if;
exit when Is_Empty;
end loop;
return Is_Empty;
end Empty_Range;
-----------
-- Equal --
-----------
function Equal (L, H : Node_Id) return Boolean is
begin
if L = H then
return True;
elsif Local_Compile_Time_Known_Value (L)
and then Local_Compile_Time_Known_Value (H)
then
return UI_Eq (Local_Expr_Value (L), Local_Expr_Value (H));
end if;
return False;
end Equal;
----------------
-- Gen_Assign --
----------------
function Gen_Assign (Ind : Node_Id; Expr : Node_Id) return List_Id is
L : constant List_Id := New_List;
A : Node_Id;
New_Indexes : List_Id;
Indexed_Comp : Node_Id;
Expr_Q : Node_Id;
Comp_Type : Entity_Id := Empty;
function Add_Loop_Actions (Lis : List_Id) return List_Id;
-- Collect insert_actions generated in the construction of a
-- loop, and prepend them to the sequence of assignments to
-- complete the eventual body of the loop.
----------------------
-- Add_Loop_Actions --
----------------------
function Add_Loop_Actions (Lis : List_Id) return List_Id is
Res : List_Id;
begin
-- Ada 2005 (AI-287): Do nothing else in case of default
-- initialized component.
if No (Expr) then
return Lis;
elsif Nkind (Parent (Expr)) = N_Component_Association
and then Present (Loop_Actions (Parent (Expr)))
then
Append_List (Lis, Loop_Actions (Parent (Expr)));
Res := Loop_Actions (Parent (Expr));
Set_Loop_Actions (Parent (Expr), No_List);
return Res;
else
return Lis;
end if;
end Add_Loop_Actions;
-- Start of processing for Gen_Assign
begin
if No (Indexes) then
New_Indexes := New_List;
else
New_Indexes := New_Copy_List_Tree (Indexes);
end if;
Append_To (New_Indexes, Ind);
if Present (Next_Index (Index)) then
return
Add_Loop_Actions (
Build_Array_Aggr_Code
(N => Expr,
Ctype => Ctype,
Index => Next_Index (Index),
Into => Into,
Scalar_Comp => Scalar_Comp,
Indexes => New_Indexes));
end if;
-- If we get here then we are at a bottom-level (sub-)aggregate
Indexed_Comp :=
Checks_Off
(Make_Indexed_Component (Loc,
Prefix => New_Copy_Tree (Into),
Expressions => New_Indexes));
Set_Assignment_OK (Indexed_Comp);
-- Ada 2005 (AI-287): In case of default initialized component, Expr
-- is not present (and therefore we also initialize Expr_Q to empty).
if No (Expr) then
Expr_Q := Empty;
elsif Nkind (Expr) = N_Qualified_Expression then
Expr_Q := Expression (Expr);
else
Expr_Q := Expr;
end if;
if Present (Etype (N))
and then Etype (N) /= Any_Composite
then
Comp_Type := Component_Type (Etype (N));
pragma Assert (Comp_Type = Ctype); -- AI-287
elsif Present (Next (First (New_Indexes))) then
-- Ada 2005 (AI-287): Do nothing in case of default initialized
-- component because we have received the component type in
-- the formal parameter Ctype.
-- ??? Some assert pragmas have been added to check if this new
-- formal can be used to replace this code in all cases.
if Present (Expr) then
-- This is a multidimensional array. Recover the component
-- type from the outermost aggregate, because subaggregates
-- do not have an assigned type.
declare
P : Node_Id;
begin
P := Parent (Expr);
while Present (P) loop
if Nkind (P) = N_Aggregate
and then Present (Etype (P))
then
Comp_Type := Component_Type (Etype (P));
exit;
else
P := Parent (P);
end if;
end loop;
pragma Assert (Comp_Type = Ctype); -- AI-287
end;
end if;
end if;
-- Ada 2005 (AI-287): We only analyze the expression in case of non-
-- default initialized components (otherwise Expr_Q is not present).
if Present (Expr_Q)
and then Nkind_In (Expr_Q, N_Aggregate, N_Extension_Aggregate)
then
-- At this stage the Expression may not have been analyzed yet
-- because the array aggregate code has not been updated to use
-- the Expansion_Delayed flag and avoid analysis altogether to
-- solve the same problem (see Resolve_Aggr_Expr). So let us do
-- the analysis of non-array aggregates now in order to get the
-- value of Expansion_Delayed flag for the inner aggregate ???
if Present (Comp_Type) and then not Is_Array_Type (Comp_Type) then
Analyze_And_Resolve (Expr_Q, Comp_Type);
end if;
if Is_Delayed_Aggregate (Expr_Q) then
-- This is either a subaggregate of a multidimensional array,
-- or a component of an array type whose component type is
-- also an array. In the latter case, the expression may have
-- component associations that provide different bounds from
-- those of the component type, and sliding must occur. Instead
-- of decomposing the current aggregate assignment, force the
-- re-analysis of the assignment, so that a temporary will be
-- generated in the usual fashion, and sliding will take place.
if Nkind (Parent (N)) = N_Assignment_Statement
and then Is_Array_Type (Comp_Type)
and then Present (Component_Associations (Expr_Q))
and then Must_Slide (Comp_Type, Etype (Expr_Q))
then
Set_Expansion_Delayed (Expr_Q, False);
Set_Analyzed (Expr_Q, False);
else
return
Add_Loop_Actions (
Late_Expansion (Expr_Q, Etype (Expr_Q), Indexed_Comp));
end if;
end if;
end if;
-- Ada 2005 (AI-287): In case of default initialized component, call
-- the initialization subprogram associated with the component type.
-- If the component type is an access type, add an explicit null
-- assignment, because for the back-end there is an initialization
-- present for the whole aggregate, and no default initialization
-- will take place.
-- In addition, if the component type is controlled, we must call
-- its Initialize procedure explicitly, because there is no explicit
-- object creation that will invoke it otherwise.
if No (Expr) then
if Present (Base_Init_Proc (Base_Type (Ctype)))
or else Has_Task (Base_Type (Ctype))
then
Append_List_To (L,
Build_Initialization_Call (Loc,
Id_Ref => Indexed_Comp,
Typ => Ctype,
With_Default_Init => True));
elsif Is_Access_Type (Ctype) then
Append_To (L,
Make_Assignment_Statement (Loc,
Name => Indexed_Comp,
Expression => Make_Null (Loc)));
end if;
if Needs_Finalization (Ctype) then
Append_To (L,
Make_Init_Call (
Obj_Ref => New_Copy_Tree (Indexed_Comp),
Typ => Ctype));
end if;
else
-- Now generate the assignment with no associated controlled
-- actions since the target of the assignment may not have been
-- initialized, it is not possible to Finalize it as expected by
-- normal controlled assignment. The rest of the controlled
-- actions are done manually with the proper finalization list
-- coming from the context.
A :=
Make_OK_Assignment_Statement (Loc,
Name => Indexed_Comp,
Expression => New_Copy_Tree (Expr));
if Present (Comp_Type) and then Needs_Finalization (Comp_Type) then
Set_No_Ctrl_Actions (A);
-- If this is an aggregate for an array of arrays, each
-- sub-aggregate will be expanded as well, and even with
-- No_Ctrl_Actions the assignments of inner components will
-- require attachment in their assignments to temporaries.
-- These temporaries must be finalized for each subaggregate,
-- to prevent multiple attachments of the same temporary
-- location to same finalization chain (and consequently
-- circular lists). To ensure that finalization takes place
-- for each subaggregate we wrap the assignment in a block.
if Is_Array_Type (Comp_Type)
and then Nkind (Expr) = N_Aggregate
then
A :=
Make_Block_Statement (Loc,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (A)));
end if;
end if;
Append_To (L, A);
-- Adjust the tag if tagged (because of possible view
-- conversions), unless compiling for a VM where
-- tags are implicit.
if Present (Comp_Type)
and then Is_Tagged_Type (Comp_Type)
and then Tagged_Type_Expansion
then
declare
Full_Typ : constant Entity_Id := Underlying_Type (Comp_Type);
begin
A :=
Make_OK_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Indexed_Comp),
Selector_Name =>
New_Reference_To
(First_Tag_Component (Full_Typ), Loc)),
Expression =>
Unchecked_Convert_To (RTE (RE_Tag),
New_Reference_To
(Node (First_Elmt (Access_Disp_Table (Full_Typ))),
Loc)));
Append_To (L, A);
end;
end if;
-- Adjust and attach the component to the proper final list, which
-- can be the controller of the outer record object or the final
-- list associated with the scope.
-- If the component is itself an array of controlled types, whose
-- value is given by a sub-aggregate, then the attach calls have
-- been generated when individual subcomponent are assigned, and
-- must not be done again to prevent malformed finalization chains
-- (see comments above, concerning the creation of a block to hold
-- inner finalization actions).
if Present (Comp_Type)
and then Needs_Finalization (Comp_Type)
and then not Is_Limited_Type (Comp_Type)
and then not
(Is_Array_Type (Comp_Type)
and then Is_Controlled (Component_Type (Comp_Type))
and then Nkind (Expr) = N_Aggregate)
then
Append_To (L,
Make_Adjust_Call (
Obj_Ref => New_Copy_Tree (Indexed_Comp),
Typ => Comp_Type));
end if;
end if;
return Add_Loop_Actions (L);
end Gen_Assign;
--------------
-- Gen_Loop --
--------------
function Gen_Loop (L, H : Node_Id; Expr : Node_Id) return List_Id is
L_J : Node_Id;
L_L : Node_Id;
-- Index_Base'(L)
L_H : Node_Id;
-- Index_Base'(H)
L_Range : Node_Id;
-- Index_Base'(L) .. Index_Base'(H)
L_Iteration_Scheme : Node_Id;
-- L_J in Index_Base'(L) .. Index_Base'(H)
L_Body : List_Id;
-- The statements to execute in the loop
S : constant List_Id := New_List;
-- List of statements
Tcopy : Node_Id;
-- Copy of expression tree, used for checking purposes
begin
-- If loop bounds define an empty range return the null statement
if Empty_Range (L, H) then
Append_To (S, Make_Null_Statement (Loc));
-- Ada 2005 (AI-287): Nothing else need to be done in case of
-- default initialized component.
if No (Expr) then
null;
else
-- The expression must be type-checked even though no component
-- of the aggregate will have this value. This is done only for
-- actual components of the array, not for subaggregates. Do
-- the check on a copy, because the expression may be shared
-- among several choices, some of which might be non-null.
if Present (Etype (N))
and then Is_Array_Type (Etype (N))
and then No (Next_Index (Index))
then
Expander_Mode_Save_And_Set (False);
Tcopy := New_Copy_Tree (Expr);
Set_Parent (Tcopy, N);
Analyze_And_Resolve (Tcopy, Component_Type (Etype (N)));
Expander_Mode_Restore;
end if;
end if;
return S;
-- If loop bounds are the same then generate an assignment
elsif Equal (L, H) then
return Gen_Assign (New_Copy_Tree (L), Expr);
-- If H - L <= 2 then generate a sequence of assignments when we are
-- processing the bottom most aggregate and it contains scalar
-- components.
elsif No (Next_Index (Index))
and then Scalar_Comp
and then Local_Compile_Time_Known_Value (L)
and then Local_Compile_Time_Known_Value (H)
and then Local_Expr_Value (H) - Local_Expr_Value (L) <= 2
then
Append_List_To (S, Gen_Assign (New_Copy_Tree (L), Expr));
Append_List_To (S, Gen_Assign (Add (1, To => L), Expr));
if Local_Expr_Value (H) - Local_Expr_Value (L) = 2 then
Append_List_To (S, Gen_Assign (Add (2, To => L), Expr));
end if;
return S;
end if;
-- Otherwise construct the loop, starting with the loop index L_J
L_J := Make_Temporary (Loc, 'J', L);
-- Construct "L .. H" in Index_Base. We use a qualified expression
-- for the bound to convert to the index base, but we don't need
-- to do that if we already have the base type at hand.
if Etype (L) = Index_Base then
L_L := L;
else
L_L :=
Make_Qualified_Expression (Loc,
Subtype_Mark => Index_Base_Name,
Expression => L);
end if;
if Etype (H) = Index_Base then
L_H := H;
else
L_H :=
Make_Qualified_Expression (Loc,
Subtype_Mark => Index_Base_Name,
Expression => H);
end if;
L_Range :=
Make_Range (Loc,
Low_Bound => L_L,
High_Bound => L_H);
-- Construct "for L_J in Index_Base range L .. H"
L_Iteration_Scheme :=
Make_Iteration_Scheme
(Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification
(Loc,
Defining_Identifier => L_J,
Discrete_Subtype_Definition => L_Range));
-- Construct the statements to execute in the loop body
L_Body := Gen_Assign (New_Reference_To (L_J, Loc), Expr);
-- Construct the final loop
Append_To (S, Make_Implicit_Loop_Statement
(Node => N,
Identifier => Empty,
Iteration_Scheme => L_Iteration_Scheme,
Statements => L_Body));
-- A small optimization: if the aggregate is initialized with a box
-- and the component type has no initialization procedure, remove the
-- useless empty loop.
if Nkind (First (S)) = N_Loop_Statement
and then Is_Empty_List (Statements (First (S)))
then
return New_List (Make_Null_Statement (Loc));
else
return S;
end if;
end Gen_Loop;
---------------
-- Gen_While --
---------------
-- The code built is
-- W_J : Index_Base := L;
-- while W_J < H loop
-- W_J := Index_Base'Succ (W);
-- L_Body;
-- end loop;
function Gen_While (L, H : Node_Id; Expr : Node_Id) return List_Id is
W_J : Node_Id;
W_Decl : Node_Id;
-- W_J : Base_Type := L;
W_Iteration_Scheme : Node_Id;
-- while W_J < H
W_Index_Succ : Node_Id;
-- Index_Base'Succ (J)
W_Increment : Node_Id;
-- W_J := Index_Base'Succ (W)
W_Body : constant List_Id := New_List;
-- The statements to execute in the loop
S : constant List_Id := New_List;
-- list of statement
begin
-- If loop bounds define an empty range or are equal return null
if Empty_Range (L, H) or else Equal (L, H) then
Append_To (S, Make_Null_Statement (Loc));
return S;
end if;
-- Build the decl of W_J
W_J := Make_Temporary (Loc, 'J', L);
W_Decl :=
Make_Object_Declaration
(Loc,
Defining_Identifier => W_J,
Object_Definition => Index_Base_Name,
Expression => L);
-- Theoretically we should do a New_Copy_Tree (L) here, but we know
-- that in this particular case L is a fresh Expr generated by
-- Add which we are the only ones to use.
Append_To (S, W_Decl);
-- Construct " while W_J < H"
W_Iteration_Scheme :=
Make_Iteration_Scheme
(Loc,
Condition => Make_Op_Lt
(Loc,
Left_Opnd => New_Reference_To (W_J, Loc),
Right_Opnd => New_Copy_Tree (H)));
-- Construct the statements to execute in the loop body
W_Index_Succ :=
Make_Attribute_Reference
(Loc,
Prefix => Index_Base_Name,
Attribute_Name => Name_Succ,
Expressions => New_List (New_Reference_To (W_J, Loc)));
W_Increment :=
Make_OK_Assignment_Statement
(Loc,
Name => New_Reference_To (W_J, Loc),
Expression => W_Index_Succ);
Append_To (W_Body, W_Increment);
Append_List_To (W_Body,
Gen_Assign (New_Reference_To (W_J, Loc), Expr));
-- Construct the final loop
Append_To (S, Make_Implicit_Loop_Statement
(Node => N,
Identifier => Empty,
Iteration_Scheme => W_Iteration_Scheme,
Statements => W_Body));
return S;
end Gen_While;
---------------------
-- Index_Base_Name --
---------------------
function Index_Base_Name return Node_Id is
begin
return New_Reference_To (Index_Base, Sloc (N));
end Index_Base_Name;
------------------------------------
-- Local_Compile_Time_Known_Value --
------------------------------------
function Local_Compile_Time_Known_Value (E : Node_Id) return Boolean is
begin
return Compile_Time_Known_Value (E)
or else
(Nkind (E) = N_Attribute_Reference
and then Attribute_Name (E) = Name_Val
and then Compile_Time_Known_Value (First (Expressions (E))));
end Local_Compile_Time_Known_Value;
----------------------
-- Local_Expr_Value --
----------------------
function Local_Expr_Value (E : Node_Id) return Uint is
begin
if Compile_Time_Known_Value (E) then
return Expr_Value (E);
else
return Expr_Value (First (Expressions (E)));
end if;
end Local_Expr_Value;
-- Build_Array_Aggr_Code Variables
Assoc : Node_Id;
Choice : Node_Id;
Expr : Node_Id;
Typ : Entity_Id;
Others_Expr : Node_Id := Empty;
Others_Box_Present : Boolean := False;
Aggr_L : constant Node_Id := Low_Bound (Aggregate_Bounds (N));
Aggr_H : constant Node_Id := High_Bound (Aggregate_Bounds (N));
-- The aggregate bounds of this specific sub-aggregate. Note that if
-- the code generated by Build_Array_Aggr_Code is executed then these
-- bounds are OK. Otherwise a Constraint_Error would have been raised.
Aggr_Low : constant Node_Id := Duplicate_Subexpr_No_Checks (Aggr_L);
Aggr_High : constant Node_Id := Duplicate_Subexpr_No_Checks (Aggr_H);
-- After Duplicate_Subexpr these are side-effect free
Low : Node_Id;
High : Node_Id;
Nb_Choices : Nat := 0;
Table : Case_Table_Type (1 .. Number_Of_Choices (N));
-- Used to sort all the different choice values
Nb_Elements : Int;
-- Number of elements in the positional aggregate
New_Code : constant List_Id := New_List;
-- Start of processing for Build_Array_Aggr_Code
begin
-- First before we start, a special case. if we have a bit packed
-- array represented as a modular type, then clear the value to
-- zero first, to ensure that unused bits are properly cleared.
Typ := Etype (N);
if Present (Typ)
and then Is_Bit_Packed_Array (Typ)
and then Is_Modular_Integer_Type (Packed_Array_Type (Typ))
then
Append_To (New_Code,
Make_Assignment_Statement (Loc,
Name => New_Copy_Tree (Into),
Expression =>
Unchecked_Convert_To (Typ,
Make_Integer_Literal (Loc, Uint_0))));
end if;
-- If the component type contains tasks, we need to build a Master
-- entity in the current scope, because it will be needed if build-
-- in-place functions are called in the expanded code.
if Nkind (Parent (N)) = N_Object_Declaration
and then Has_Task (Typ)
then
Build_Master_Entity (Defining_Identifier (Parent (N)));
end if;
-- STEP 1: Process component associations
-- For those associations that may generate a loop, initialize
-- Loop_Actions to collect inserted actions that may be crated.
-- Skip this if no component associations
if No (Expressions (N)) then
-- STEP 1 (a): Sort the discrete choices
Assoc := First (Component_Associations (N));
while Present (Assoc) loop
Choice := First (Choices (Assoc));
while Present (Choice) loop
if Nkind (Choice) = N_Others_Choice then
Set_Loop_Actions (Assoc, New_List);
if Box_Present (Assoc) then
Others_Box_Present := True;
else
Others_Expr := Expression (Assoc);
end if;
exit;
end if;
Get_Index_Bounds (Choice, Low, High);
if Low /= High then
Set_Loop_Actions (Assoc, New_List);
end if;
Nb_Choices := Nb_Choices + 1;
if Box_Present (Assoc) then
Table (Nb_Choices) := (Choice_Lo => Low,
Choice_Hi => High,
Choice_Node => Empty);
else
Table (Nb_Choices) := (Choice_Lo => Low,
Choice_Hi => High,
Choice_Node => Expression (Assoc));
end if;
Next (Choice);
end loop;
Next (Assoc);
end loop;
-- If there is more than one set of choices these must be static
-- and we can therefore sort them. Remember that Nb_Choices does not
-- account for an others choice.
if Nb_Choices > 1 then
Sort_Case_Table (Table);
end if;
-- STEP 1 (b): take care of the whole set of discrete choices
for J in 1 .. Nb_Choices loop
Low := Table (J).Choice_Lo;
High := Table (J).Choice_Hi;
Expr := Table (J).Choice_Node;
Append_List (Gen_Loop (Low, High, Expr), To => New_Code);
end loop;
-- STEP 1 (c): generate the remaining loops to cover others choice
-- We don't need to generate loops over empty gaps, but if there is
-- a single empty range we must analyze the expression for semantics
if Present (Others_Expr) or else Others_Box_Present then
declare
First : Boolean := True;
begin
for J in 0 .. Nb_Choices loop
if J = 0 then
Low := Aggr_Low;
else
Low := Add (1, To => Table (J).Choice_Hi);
end if;
if J = Nb_Choices then
High := Aggr_High;
else
High := Add (-1, To => Table (J + 1).Choice_Lo);
end if;
-- If this is an expansion within an init proc, make
-- sure that discriminant references are replaced by
-- the corresponding discriminal.
if Inside_Init_Proc then
if Is_Entity_Name (Low)
and then Ekind (Entity (Low)) = E_Discriminant
then
Set_Entity (Low, Discriminal (Entity (Low)));
end if;
if Is_Entity_Name (High)
and then Ekind (Entity (High)) = E_Discriminant
then
Set_Entity (High, Discriminal (Entity (High)));
end if;
end if;
if First
or else not Empty_Range (Low, High)
then
First := False;
Append_List
(Gen_Loop (Low, High, Others_Expr), To => New_Code);
end if;
end loop;
end;
end if;
-- STEP 2: Process positional components
else
-- STEP 2 (a): Generate the assignments for each positional element
-- Note that here we have to use Aggr_L rather than Aggr_Low because
-- Aggr_L is analyzed and Add wants an analyzed expression.
Expr := First (Expressions (N));
Nb_Elements := -1;
while Present (Expr) loop
Nb_Elements := Nb_Elements + 1;
Append_List (Gen_Assign (Add (Nb_Elements, To => Aggr_L), Expr),
To => New_Code);
Next (Expr);
end loop;
-- STEP 2 (b): Generate final loop if an others choice is present
-- Here Nb_Elements gives the offset of the last positional element.
if Present (Component_Associations (N)) then
Assoc := Last (Component_Associations (N));
-- Ada 2005 (AI-287)
if Box_Present (Assoc) then
Append_List (Gen_While (Add (Nb_Elements, To => Aggr_L),
Aggr_High,
Empty),
To => New_Code);
else
Expr := Expression (Assoc);
Append_List (Gen_While (Add (Nb_Elements, To => Aggr_L),
Aggr_High,
Expr), -- AI-287
To => New_Code);
end if;
end if;
end if;
return New_Code;
end Build_Array_Aggr_Code;
----------------------------
-- Build_Record_Aggr_Code --
----------------------------
function Build_Record_Aggr_Code
(N : Node_Id;
Typ : Entity_Id;
Lhs : Node_Id) return List_Id
is
Loc : constant Source_Ptr := Sloc (N);
L : constant List_Id := New_List;
N_Typ : constant Entity_Id := Etype (N);
Comp : Node_Id;
Instr : Node_Id;
Ref : Node_Id;
Target : Entity_Id;
Comp_Type : Entity_Id;
Selector : Entity_Id;
Comp_Expr : Node_Id;
Expr_Q : Node_Id;
-- If this is an internal aggregate, the External_Final_List is an
-- expression for the controller record of the enclosing type.
-- If the current aggregate has several controlled components, this
-- expression will appear in several calls to attach to the finali-
-- zation list, and it must not be shared.
Ancestor_Is_Expression : Boolean := False;
Ancestor_Is_Subtype_Mark : Boolean := False;
Init_Typ : Entity_Id := Empty;
Finalization_Done : Boolean := False;
-- True if Generate_Finalization_Actions has already been called; calls
-- after the first do nothing.
function Ancestor_Discriminant_Value (Disc : Entity_Id) return Node_Id;
-- Returns the value that the given discriminant of an ancestor type
-- should receive (in the absence of a conflict with the value provided
-- by an ancestor part of an extension aggregate).
procedure Check_Ancestor_Discriminants (Anc_Typ : Entity_Id);
-- Check that each of the discriminant values defined by the ancestor
-- part of an extension aggregate match the corresponding values
-- provided by either an association of the aggregate or by the
-- constraint imposed by a parent type (RM95-4.3.2(8)).
function Compatible_Int_Bounds
(Agg_Bounds : Node_Id;
Typ_Bounds : Node_Id) return Boolean;
-- Return true if Agg_Bounds are equal or within Typ_Bounds. It is
-- assumed that both bounds are integer ranges.
procedure Generate_Finalization_Actions;
-- Deal with the various controlled type data structure initializations
-- (but only if it hasn't been done already).
function Get_Constraint_Association (T : Entity_Id) return Node_Id;
-- Returns the first discriminant association in the constraint
-- associated with T, if any, otherwise returns Empty.
procedure Init_Hidden_Discriminants (Typ : Entity_Id; List : List_Id);
-- If Typ is derived, and constrains discriminants of the parent type,
-- these discriminants are not components of the aggregate, and must be
-- initialized. The assignments are appended to List.
function Is_Int_Range_Bounds (Bounds : Node_Id) return Boolean;
-- Check whether Bounds is a range node and its lower and higher bounds
-- are integers literals.
---------------------------------
-- Ancestor_Discriminant_Value --
---------------------------------
function Ancestor_Discriminant_Value (Disc : Entity_Id) return Node_Id is
Assoc : Node_Id;
Assoc_Elmt : Elmt_Id;
Aggr_Comp : Entity_Id;
Corresp_Disc : Entity_Id;
Current_Typ : Entity_Id := Base_Type (Typ);
Parent_Typ : Entity_Id;
Parent_Disc : Entity_Id;
Save_Assoc : Node_Id := Empty;
begin
-- First check any discriminant associations to see if any of them
-- provide a value for the discriminant.
if Present (Discriminant_Specifications (Parent (Current_Typ))) then
Assoc := First (Component_Associations (N));
while Present (Assoc) loop
Aggr_Comp := Entity (First (Choices (Assoc)));
if Ekind (Aggr_Comp) = E_Discriminant then
Save_Assoc := Expression (Assoc);
Corresp_Disc := Corresponding_Discriminant (Aggr_Comp);
while Present (Corresp_Disc) loop
-- If found a corresponding discriminant then return the
-- value given in the aggregate. (Note: this is not
-- correct in the presence of side effects. ???)
if Disc = Corresp_Disc then
return Duplicate_Subexpr (Expression (Assoc));
end if;
Corresp_Disc :=
Corresponding_Discriminant (Corresp_Disc);
end loop;
end if;
Next (Assoc);
end loop;
end if;
-- No match found in aggregate, so chain up parent types to find
-- a constraint that defines the value of the discriminant.
Parent_Typ := Etype (Current_Typ);
while Current_Typ /= Parent_Typ loop
if Has_Discriminants (Parent_Typ)
and then not Has_Unknown_Discriminants (Parent_Typ)
then
Parent_Disc := First_Discriminant (Parent_Typ);
-- We either get the association from the subtype indication
-- of the type definition itself, or from the discriminant
-- constraint associated with the type entity (which is
-- preferable, but it's not always present ???)
if Is_Empty_Elmt_List (
Discriminant_Constraint (Current_Typ))
then
Assoc := Get_Constraint_Association (Current_Typ);
Assoc_Elmt := No_Elmt;
else
Assoc_Elmt :=
First_Elmt (Discriminant_Constraint (Current_Typ));
Assoc := Node (Assoc_Elmt);
end if;
-- Traverse the discriminants of the parent type looking
-- for one that corresponds.
while Present (Parent_Disc) and then Present (Assoc) loop
Corresp_Disc := Parent_Disc;
while Present (Corresp_Disc)
and then Disc /= Corresp_Disc
loop
Corresp_Disc :=
Corresponding_Discriminant (Corresp_Disc);
end loop;
if Disc = Corresp_Disc then
if Nkind (Assoc) = N_Discriminant_Association then
Assoc := Expression (Assoc);
end if;
-- If the located association directly denotes a
-- discriminant, then use the value of a saved
-- association of the aggregate. This is a kludge to
-- handle certain cases involving multiple discriminants
-- mapped to a single discriminant of a descendant. It's
-- not clear how to locate the appropriate discriminant
-- value for such cases. ???
if Is_Entity_Name (Assoc)
and then Ekind (Entity (Assoc)) = E_Discriminant
then
Assoc := Save_Assoc;
end if;
return Duplicate_Subexpr (Assoc);
end if;
Next_Discriminant (Parent_Disc);
if No (Assoc_Elmt) then
Next (Assoc);
else
Next_Elmt (Assoc_Elmt);
if Present (Assoc_Elmt) then
Assoc := Node (Assoc_Elmt);
else
Assoc := Empty;
end if;
end if;
end loop;
end if;
Current_Typ := Parent_Typ;
Parent_Typ := Etype (Current_Typ);
end loop;
-- In some cases there's no ancestor value to locate (such as
-- when an ancestor part given by an expression defines the
-- discriminant value).
return Empty;
end Ancestor_Discriminant_Value;
----------------------------------
-- Check_Ancestor_Discriminants --
----------------------------------
procedure Check_Ancestor_Discriminants (Anc_Typ : Entity_Id) is
Discr : Entity_Id;
Disc_Value : Node_Id;
Cond : Node_Id;
begin
Discr := First_Discriminant (Base_Type (Anc_Typ));
while Present (Discr) loop
Disc_Value := Ancestor_Discriminant_Value (Discr);
if Present (Disc_Value) then
Cond := Make_Op_Ne (Loc,
Left_Opnd =>
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name => New_Occurrence_Of (Discr, Loc)),
Right_Opnd => Disc_Value);
Append_To (L,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
Reason => CE_Discriminant_Check_Failed));
end if;
Next_Discriminant (Discr);
end loop;
end Check_Ancestor_Discriminants;
---------------------------
-- Compatible_Int_Bounds --
---------------------------
function Compatible_Int_Bounds
(Agg_Bounds : Node_Id;
Typ_Bounds : Node_Id) return Boolean
is
Agg_Lo : constant Uint := Intval (Low_Bound (Agg_Bounds));
Agg_Hi : constant Uint := Intval (High_Bound (Agg_Bounds));
Typ_Lo : constant Uint := Intval (Low_Bound (Typ_Bounds));
Typ_Hi : constant Uint := Intval (High_Bound (Typ_Bounds));
begin
return Typ_Lo <= Agg_Lo and then Agg_Hi <= Typ_Hi;
end Compatible_Int_Bounds;
--------------------------------
-- Get_Constraint_Association --
--------------------------------
function Get_Constraint_Association (T : Entity_Id) return Node_Id is
Indic : Node_Id;
Typ : Entity_Id;
begin
Typ := T;
-- Handle private types in instances
if In_Instance
and then Is_Private_Type (Typ)
and then Present (Full_View (Typ))
then
Typ := Full_View (Typ);
end if;
Indic := Subtype_Indication (Type_Definition (Parent (Typ)));
-- ??? Also need to cover case of a type mark denoting a subtype
-- with constraint.
if Nkind (Indic) = N_Subtype_Indication
and then Present (Constraint (Indic))
then
return First (Constraints (Constraint (Indic)));
end if;
return Empty;
end Get_Constraint_Association;
-------------------------------
-- Init_Hidden_Discriminants --
-------------------------------
procedure Init_Hidden_Discriminants (Typ : Entity_Id; List : List_Id) is
Btype : Entity_Id;
Parent_Type : Entity_Id;
Disc : Entity_Id;
Discr_Val : Elmt_Id;
begin
Btype := Base_Type (Typ);
while Is_Derived_Type (Btype)
and then Present (Stored_Constraint (Btype))
loop
Parent_Type := Etype (Btype);
Disc := First_Discriminant (Parent_Type);
Discr_Val := First_Elmt (Stored_Constraint (Base_Type (Typ)));
while Present (Discr_Val) loop
-- Only those discriminants of the parent that are not
-- renamed by discriminants of the derived type need to
-- be added explicitly.
if not Is_Entity_Name (Node (Discr_Val))
or else Ekind (Entity (Node (Discr_Val))) /= E_Discriminant
then
Comp_Expr :=
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name => New_Occurrence_Of (Disc, Loc));
Instr :=
Make_OK_Assignment_Statement (Loc,
Name => Comp_Expr,
Expression => New_Copy_Tree (Node (Discr_Val)));
Set_No_Ctrl_Actions (Instr);
Append_To (List, Instr);
end if;
Next_Discriminant (Disc);
Next_Elmt (Discr_Val);
end loop;
Btype := Base_Type (Parent_Type);
end loop;
end Init_Hidden_Discriminants;
-------------------------
-- Is_Int_Range_Bounds --
-------------------------
function Is_Int_Range_Bounds (Bounds : Node_Id) return Boolean is
begin
return Nkind (Bounds) = N_Range
and then Nkind (Low_Bound (Bounds)) = N_Integer_Literal
and then Nkind (High_Bound (Bounds)) = N_Integer_Literal;
end Is_Int_Range_Bounds;
-----------------------------------
-- Generate_Finalization_Actions --
-----------------------------------
procedure Generate_Finalization_Actions is
begin
-- Do the work only the first time this is called
if Finalization_Done then
return;
end if;
Finalization_Done := True;
-- Determine the external finalization list. It is either the
-- finalization list of the outer-scope or the one coming from
-- an outer aggregate. When the target is not a temporary, the
-- proper scope is the scope of the target rather than the
-- potentially transient current scope.
if Is_Controlled (Typ)
and then Ancestor_Is_Subtype_Mark
then
Ref := Convert_To (Init_Typ, New_Copy_Tree (Target));
Set_Assignment_OK (Ref);
Append_To (L,
Make_Procedure_Call_Statement (Loc,
Name =>
New_Reference_To
(Find_Prim_Op (Init_Typ, Name_Initialize), Loc),
Parameter_Associations => New_List (New_Copy_Tree (Ref))));
end if;
end Generate_Finalization_Actions;
function Rewrite_Discriminant (Expr : Node_Id) return Traverse_Result;
-- If default expression of a component mentions a discriminant of the
-- type, it must be rewritten as the discriminant of the target object.
function Replace_Type (Expr : Node_Id) return Traverse_Result;
-- If the aggregate contains a self-reference, traverse each expression
-- to replace a possible self-reference with a reference to the proper
-- component of the target of the assignment.
--------------------------
-- Rewrite_Discriminant --
--------------------------
function Rewrite_Discriminant (Expr : Node_Id) return Traverse_Result is
begin
if Is_Entity_Name (Expr)
and then Present (Entity (Expr))
and then Ekind (Entity (Expr)) = E_In_Parameter
and then Present (Discriminal_Link (Entity (Expr)))
and then Scope (Discriminal_Link (Entity (Expr)))
= Base_Type (Etype (N))
then
Rewrite (Expr,
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Lhs),
Selector_Name => Make_Identifier (Loc, Chars (Expr))));
end if;
return OK;
end Rewrite_Discriminant;
------------------
-- Replace_Type --
------------------
function Replace_Type (Expr : Node_Id) return Traverse_Result is
begin
-- Note regarding the Root_Type test below: Aggregate components for
-- self-referential types include attribute references to the current
-- instance, of the form: Typ'access, etc.. These references are
-- rewritten as references to the target of the aggregate: the
-- left-hand side of an assignment, the entity in a declaration,
-- or a temporary. Without this test, we would improperly extended
-- this rewriting to attribute references whose prefix was not the
-- type of the aggregate.
if Nkind (Expr) = N_Attribute_Reference
and then Is_Entity_Name (Prefix (Expr))
and then Is_Type (Entity (Prefix (Expr)))
and then Root_Type (Etype (N)) = Root_Type (Entity (Prefix (Expr)))
then
if Is_Entity_Name (Lhs) then
Rewrite (Prefix (Expr),
New_Occurrence_Of (Entity (Lhs), Loc));
elsif Nkind (Lhs) = N_Selected_Component then
Rewrite (Expr,
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Unrestricted_Access,
Prefix => New_Copy_Tree (Lhs)));
Set_Analyzed (Parent (Expr), False);
else
Rewrite (Expr,
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Unrestricted_Access,
Prefix => New_Copy_Tree (Lhs)));
Set_Analyzed (Parent (Expr), False);
end if;
end if;
return OK;
end Replace_Type;
procedure Replace_Self_Reference is
new Traverse_Proc (Replace_Type);
procedure Replace_Discriminants is
new Traverse_Proc (Rewrite_Discriminant);
-- Start of processing for Build_Record_Aggr_Code
begin
if Has_Self_Reference (N) then
Replace_Self_Reference (N);
end if;
-- If the target of the aggregate is class-wide, we must convert it
-- to the actual type of the aggregate, so that the proper components
-- are visible. We know already that the types are compatible.
if Present (Etype (Lhs))
and then Is_Class_Wide_Type (Etype (Lhs))
then
Target := Unchecked_Convert_To (Typ, Lhs);
else
Target := Lhs;
end if;
-- Deal with the ancestor part of extension aggregates or with the
-- discriminants of the root type.
if Nkind (N) = N_Extension_Aggregate then
declare
Ancestor : constant Node_Id := Ancestor_Part (N);
Assign : List_Id;
begin
-- If the ancestor part is a subtype mark "T", we generate
-- init-proc (T (tmp)); if T is constrained and
-- init-proc (S (tmp)); where S applies an appropriate
-- constraint if T is unconstrained
if Is_Entity_Name (Ancestor)
and then Is_Type (Entity (Ancestor))
then
Ancestor_Is_Subtype_Mark := True;
if Is_Constrained (Entity (Ancestor)) then
Init_Typ := Entity (Ancestor);
-- For an ancestor part given by an unconstrained type mark,
-- create a subtype constrained by appropriate corresponding
-- discriminant values coming from either associations of the
-- aggregate or a constraint on a parent type. The subtype will
-- be used to generate the correct default value for the
-- ancestor part.
elsif Has_Discriminants (Entity (Ancestor)) then
declare
Anc_Typ : constant Entity_Id := Entity (Ancestor);
Anc_Constr : constant List_Id := New_List;
Discrim : Entity_Id;
Disc_Value : Node_Id;
New_Indic : Node_Id;
Subt_Decl : Node_Id;
begin
Discrim := First_Discriminant (Anc_Typ);
while Present (Discrim) loop
Disc_Value := Ancestor_Discriminant_Value (Discrim);
Append_To (Anc_Constr, Disc_Value);
Next_Discriminant (Discrim);
end loop;
New_Indic :=
Make_Subtype_Indication (Loc,
Subtype_Mark => New_Occurrence_Of (Anc_Typ, Loc),
Constraint =>
Make_Index_Or_Discriminant_Constraint (Loc,
Constraints => Anc_Constr));
Init_Typ := Create_Itype (Ekind (Anc_Typ), N);
Subt_Decl :=
Make_Subtype_Declaration (Loc,
Defining_Identifier => Init_Typ,
Subtype_Indication => New_Indic);
-- Itypes must be analyzed with checks off Declaration
-- must have a parent for proper handling of subsidiary
-- actions.
Set_Parent (Subt_Decl, N);
Analyze (Subt_Decl, Suppress => All_Checks);
end;
end if;
Ref := Convert_To (Init_Typ, New_Copy_Tree (Target));
Set_Assignment_OK (Ref);
if not Is_Interface (Init_Typ) then
Append_List_To (L,
Build_Initialization_Call (Loc,
Id_Ref => Ref,
Typ => Init_Typ,
In_Init_Proc => Within_Init_Proc,
With_Default_Init => Has_Default_Init_Comps (N)
or else
Has_Task (Base_Type (Init_Typ))));
if Is_Constrained (Entity (Ancestor))
and then Has_Discriminants (Entity (Ancestor))
then
Check_Ancestor_Discriminants (Entity (Ancestor));
end if;
end if;
-- Handle calls to C++ constructors
elsif Is_CPP_Constructor_Call (Ancestor) then
Init_Typ := Etype (Ancestor);
Ref := Convert_To (Init_Typ, New_Copy_Tree (Target));
Set_Assignment_OK (Ref);
Append_List_To (L,
Build_Initialization_Call (Loc,
Id_Ref => Ref,
Typ => Init_Typ,
In_Init_Proc => Within_Init_Proc,
With_Default_Init => Has_Default_Init_Comps (N),
Constructor_Ref => Ancestor));
-- Ada 2005 (AI-287): If the ancestor part is an aggregate of
-- limited type, a recursive call expands the ancestor. Note that
-- in the limited case, the ancestor part must be either a
-- function call (possibly qualified, or wrapped in an unchecked
-- conversion) or aggregate (definitely qualified).
-- The ancestor part can also be a function call (that may be
-- transformed into an explicit dereference) or a qualification
-- of one such.
elsif Is_Limited_Type (Etype (Ancestor))
and then Nkind_In (Unqualify (Ancestor), N_Aggregate,
N_Extension_Aggregate)
then
Ancestor_Is_Expression := True;
-- Set up finalization data for enclosing record, because
-- controlled subcomponents of the ancestor part will be
-- attached to it.
Generate_Finalization_Actions;
Append_List_To (L,
Build_Record_Aggr_Code
(N => Unqualify (Ancestor),
Typ => Etype (Unqualify (Ancestor)),
Lhs => Target));
-- If the ancestor part is an expression "E", we generate
-- T (tmp) := E;
-- In Ada 2005, this includes the case of a (possibly qualified)
-- limited function call. The assignment will turn into a
-- build-in-place function call (for further details, see
-- Make_Build_In_Place_Call_In_Assignment).
else
Ancestor_Is_Expression := True;
Init_Typ := Etype (Ancestor);
-- If the ancestor part is an aggregate, force its full
-- expansion, which was delayed.
if Nkind_In (Unqualify (Ancestor), N_Aggregate,
N_Extension_Aggregate)
then
Set_Analyzed (Ancestor, False);
Set_Analyzed (Expression (Ancestor), False);
end if;
Ref := Convert_To (Init_Typ, New_Copy_Tree (Target));
Set_Assignment_OK (Ref);
-- Make the assignment without usual controlled actions since
-- we only want the post adjust but not the pre finalize here
-- Add manual adjust when necessary.
Assign := New_List (
Make_OK_Assignment_Statement (Loc,
Name => Ref,
Expression => Ancestor));
Set_No_Ctrl_Actions (First (Assign));
-- Assign the tag now to make sure that the dispatching call in
-- the subsequent deep_adjust works properly (unless VM_Target,
-- where tags are implicit).
if Tagged_Type_Expansion then
Instr :=
Make_OK_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name =>
New_Reference_To
(First_Tag_Component (Base_Type (Typ)), Loc)),
Expression =>
Unchecked_Convert_To (RTE (RE_Tag),
New_Reference_To
(Node (First_Elmt
(Access_Disp_Table (Base_Type (Typ)))),
Loc)));
Set_Assignment_OK (Name (Instr));
Append_To (Assign, Instr);
-- Ada 2005 (AI-251): If tagged type has progenitors we must
-- also initialize tags of the secondary dispatch tables.
if Has_Interfaces (Base_Type (Typ)) then
Init_Secondary_Tags
(Typ => Base_Type (Typ),
Target => Target,
Stmts_List => Assign);
end if;
end if;
-- Call Adjust manually
if Needs_Finalization (Etype (Ancestor))
and then not Is_Limited_Type (Etype (Ancestor))
then
Append_To (Assign,
Make_Adjust_Call (
Obj_Ref => New_Copy_Tree (Ref),
Typ => Etype (Ancestor)));
end if;
Append_To (L,
Make_Unsuppress_Block (Loc, Name_Discriminant_Check, Assign));
if Has_Discriminants (Init_Typ) then
Check_Ancestor_Discriminants (Init_Typ);
end if;
end if;
end;
-- Generate assignments of hidden assignments. If the base type is an
-- unchecked union, the discriminants are unknown to the back-end and
-- absent from a value of the type, so assignments for them are not
-- emitted.
if Has_Discriminants (Typ)
and then not Is_Unchecked_Union (Base_Type (Typ))
then
Init_Hidden_Discriminants (Typ, L);
end if;
-- Normal case (not an extension aggregate)
else
-- Generate the discriminant expressions, component by component.
-- If the base type is an unchecked union, the discriminants are
-- unknown to the back-end and absent from a value of the type, so
-- assignments for them are not emitted.
if Has_Discriminants (Typ)
and then not Is_Unchecked_Union (Base_Type (Typ))
then
Init_Hidden_Discriminants (Typ, L);
-- Generate discriminant init values for the visible discriminants
declare
Discriminant : Entity_Id;
Discriminant_Value : Node_Id;
begin
Discriminant := First_Stored_Discriminant (Typ);
while Present (Discriminant) loop
Comp_Expr :=
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name => New_Occurrence_Of (Discriminant, Loc));
Discriminant_Value :=
Get_Discriminant_Value (
Discriminant,
N_Typ,
Discriminant_Constraint (N_Typ));
Instr :=
Make_OK_Assignment_Statement (Loc,
Name => Comp_Expr,
Expression => New_Copy_Tree (Discriminant_Value));
Set_No_Ctrl_Actions (Instr);
Append_To (L, Instr);
Next_Stored_Discriminant (Discriminant);
end loop;
end;
end if;
end if;
-- For CPP types we generate an implicit call to the C++ default
-- constructor to ensure the proper initialization of the _Tag
-- component.
if Is_CPP_Class (Root_Type (Typ))
and then CPP_Num_Prims (Typ) > 0
then
Invoke_Constructor : declare
CPP_Parent : constant Entity_Id := Enclosing_CPP_Parent (Typ);
procedure Invoke_IC_Proc (T : Entity_Id);
-- Recursive routine used to climb to parents. Required because
-- parents must be initialized before descendants to ensure
-- propagation of inherited C++ slots.
--------------------
-- Invoke_IC_Proc --
--------------------
procedure Invoke_IC_Proc (T : Entity_Id) is
begin
-- Avoid generating extra calls. Initialization required
-- only for types defined from the level of derivation of
-- type of the constructor and the type of the aggregate.
if T = CPP_Parent then
return;
end if;
Invoke_IC_Proc (Etype (T));
-- Generate call to the IC routine
if Present (CPP_Init_Proc (T)) then
Append_To (L,
Make_Procedure_Call_Statement (Loc,
New_Reference_To (CPP_Init_Proc (T), Loc)));
end if;
end Invoke_IC_Proc;
-- Start of processing for Invoke_Constructor
begin
-- Implicit invocation of the C++ constructor
if Nkind (N) = N_Aggregate then
Append_To (L,
Make_Procedure_Call_Statement (Loc,
Name =>
New_Reference_To
(Base_Init_Proc (CPP_Parent), Loc),
Parameter_Associations => New_List (
Unchecked_Convert_To (CPP_Parent,
New_Copy_Tree (Lhs)))));
end if;
Invoke_IC_Proc (Typ);
end Invoke_Constructor;
end if;
-- Generate the assignments, component by component
-- tmp.comp1 := Expr1_From_Aggr;
-- tmp.comp2 := Expr2_From_Aggr;
-- ....
Comp := First (Component_Associations (N));
while Present (Comp) loop
Selector := Entity (First (Choices (Comp)));
-- C++ constructors
if Is_CPP_Constructor_Call (Expression (Comp)) then
Append_List_To (L,
Build_Initialization_Call (Loc,
Id_Ref => Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name =>
New_Occurrence_Of (Selector, Loc)),
Typ => Etype (Selector),
Enclos_Type => Typ,
With_Default_Init => True,
Constructor_Ref => Expression (Comp)));
-- Ada 2005 (AI-287): For each default-initialized component generate
-- a call to the corresponding IP subprogram if available.
elsif Box_Present (Comp)
and then Has_Non_Null_Base_Init_Proc (Etype (Selector))
then
if Ekind (Selector) /= E_Discriminant then
Generate_Finalization_Actions;
end if;
-- Ada 2005 (AI-287): If the component type has tasks then
-- generate the activation chain and master entities (except
-- in case of an allocator because in that case these entities
-- are generated by Build_Task_Allocate_Block_With_Init_Stmts).
declare
Ctype : constant Entity_Id := Etype (Selector);
Inside_Allocator : Boolean := False;
P : Node_Id := Parent (N);
begin
if Is_Task_Type (Ctype) or else Has_Task (Ctype) then
while Present (P) loop
if Nkind (P) = N_Allocator then
Inside_Allocator := True;
exit;
end if;
P := Parent (P);
end loop;
if not Inside_Init_Proc and not Inside_Allocator then
Build_Activation_Chain_Entity (N);
end if;
end if;
end;
Append_List_To (L,
Build_Initialization_Call (Loc,
Id_Ref => Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name =>
New_Occurrence_Of (Selector, Loc)),
Typ => Etype (Selector),
Enclos_Type => Typ,
With_Default_Init => True));
-- Prepare for component assignment
elsif Ekind (Selector) /= E_Discriminant
or else Nkind (N) = N_Extension_Aggregate
then
-- All the discriminants have now been assigned
-- This is now a good moment to initialize and attach all the
-- controllers. Their position may depend on the discriminants.
if Ekind (Selector) /= E_Discriminant then
Generate_Finalization_Actions;
end if;
Comp_Type := Underlying_Type (Etype (Selector));
Comp_Expr :=
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name => New_Occurrence_Of (Selector, Loc));
if Nkind (Expression (Comp)) = N_Qualified_Expression then
Expr_Q := Expression (Expression (Comp));
else
Expr_Q := Expression (Comp);
end if;
-- Now either create the assignment or generate the code for the
-- inner aggregate top-down.
if Is_Delayed_Aggregate (Expr_Q) then
-- We have the following case of aggregate nesting inside
-- an object declaration:
-- type Arr_Typ is array (Integer range <>) of ...;
-- type Rec_Typ (...) is record
-- Obj_Arr_Typ : Arr_Typ (A .. B);
-- end record;
-- Obj_Rec_Typ : Rec_Typ := (...,
-- Obj_Arr_Typ => (X => (...), Y => (...)));
-- The length of the ranges of the aggregate and Obj_Add_Typ
-- are equal (B - A = Y - X), but they do not coincide (X /=
-- A and B /= Y). This case requires array sliding which is
-- performed in the following manner:
-- subtype Arr_Sub is Arr_Typ (X .. Y);
-- Temp : Arr_Sub;
-- Temp (X) := (...);
-- ...
-- Temp (Y) := (...);
-- Obj_Rec_Typ.Obj_Arr_Typ := Temp;
if Ekind (Comp_Type) = E_Array_Subtype
and then Is_Int_Range_Bounds (Aggregate_Bounds (Expr_Q))
and then Is_Int_Range_Bounds (First_Index (Comp_Type))
and then not
Compatible_Int_Bounds
(Agg_Bounds => Aggregate_Bounds (Expr_Q),
Typ_Bounds => First_Index (Comp_Type))
then
-- Create the array subtype with bounds equal to those of
-- the corresponding aggregate.
declare
SubE : constant Entity_Id := Make_Temporary (Loc, 'T');
SubD : constant Node_Id :=
Make_Subtype_Declaration (Loc,
Defining_Identifier => SubE,
Subtype_Indication =>
Make_Subtype_Indication (Loc,
Subtype_Mark =>
New_Reference_To (Etype (Comp_Type), Loc),
Constraint =>
Make_Index_Or_Discriminant_Constraint
(Loc,
Constraints => New_List (
New_Copy_Tree
(Aggregate_Bounds (Expr_Q))))));
-- Create a temporary array of the above subtype which
-- will be used to capture the aggregate assignments.
TmpE : constant Entity_Id := Make_Temporary (Loc, 'A', N);
TmpD : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => TmpE,
Object_Definition => New_Reference_To (SubE, Loc));
begin
Set_No_Initialization (TmpD);
Append_To (L, SubD);
Append_To (L, TmpD);
-- Expand aggregate into assignments to the temp array
Append_List_To (L,
Late_Expansion (Expr_Q, Comp_Type,
New_Reference_To (TmpE, Loc)));
-- Slide
Append_To (L,
Make_Assignment_Statement (Loc,
Name => New_Copy_Tree (Comp_Expr),
Expression => New_Reference_To (TmpE, Loc)));
end;
-- Normal case (sliding not required)
else
Append_List_To (L,
Late_Expansion (Expr_Q, Comp_Type, Comp_Expr));
end if;
-- Expr_Q is not delayed aggregate
else
if Has_Discriminants (Typ) then
Replace_Discriminants (Expr_Q);
end if;
Instr :=
Make_OK_Assignment_Statement (Loc,
Name => Comp_Expr,
Expression => Expr_Q);
Set_No_Ctrl_Actions (Instr);
Append_To (L, Instr);
-- Adjust the tag if tagged (because of possible view
-- conversions), unless compiling for a VM where tags are
-- implicit.
-- tmp.comp._tag := comp_typ'tag;
if Is_Tagged_Type (Comp_Type)
and then Tagged_Type_Expansion
then
Instr :=
Make_OK_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Comp_Expr),
Selector_Name =>
New_Reference_To
(First_Tag_Component (Comp_Type), Loc)),
Expression =>
Unchecked_Convert_To (RTE (RE_Tag),
New_Reference_To
(Node (First_Elmt (Access_Disp_Table (Comp_Type))),
Loc)));
Append_To (L, Instr);
end if;
-- Generate:
-- Adjust (tmp.comp);
if Needs_Finalization (Comp_Type)
and then not Is_Limited_Type (Comp_Type)
then
Append_To (L,
Make_Adjust_Call (
Obj_Ref => New_Copy_Tree (Comp_Expr),
Typ => Comp_Type));
end if;
end if;
-- ???
elsif Ekind (Selector) = E_Discriminant
and then Nkind (N) /= N_Extension_Aggregate
and then Nkind (Parent (N)) = N_Component_Association
and then Is_Constrained (Typ)
then
-- We must check that the discriminant value imposed by the
-- context is the same as the value given in the subaggregate,
-- because after the expansion into assignments there is no
-- record on which to perform a regular discriminant check.
declare
D_Val : Elmt_Id;
Disc : Entity_Id;
begin
D_Val := First_Elmt (Discriminant_Constraint (Typ));
Disc := First_Discriminant (Typ);
while Chars (Disc) /= Chars (Selector) loop
Next_Discriminant (Disc);
Next_Elmt (D_Val);
end loop;
pragma Assert (Present (D_Val));
-- This check cannot performed for components that are
-- constrained by a current instance, because this is not a
-- value that can be compared with the actual constraint.
if Nkind (Node (D_Val)) /= N_Attribute_Reference
or else not Is_Entity_Name (Prefix (Node (D_Val)))
or else not Is_Type (Entity (Prefix (Node (D_Val))))
then
Append_To (L,
Make_Raise_Constraint_Error (Loc,
Condition =>
Make_Op_Ne (Loc,
Left_Opnd => New_Copy_Tree (Node (D_Val)),
Right_Opnd => Expression (Comp)),
Reason => CE_Discriminant_Check_Failed));
else
-- Find self-reference in previous discriminant assignment,
-- and replace with proper expression.
declare
Ass : Node_Id;
begin
Ass := First (L);
while Present (Ass) loop
if Nkind (Ass) = N_Assignment_Statement
and then Nkind (Name (Ass)) = N_Selected_Component
and then Chars (Selector_Name (Name (Ass))) =
Chars (Disc)
then
Set_Expression
(Ass, New_Copy_Tree (Expression (Comp)));
exit;
end if;
Next (Ass);
end loop;
end;
end if;
end;
end if;
Next (Comp);
end loop;
-- If the type is tagged, the tag needs to be initialized (unless
-- compiling for the Java VM where tags are implicit). It is done
-- late in the initialization process because in some cases, we call
-- the init proc of an ancestor which will not leave out the right tag
if Ancestor_Is_Expression then
null;
-- For CPP types we generated a call to the C++ default constructor
-- before the components have been initialized to ensure the proper
-- initialization of the _Tag component (see above).
elsif Is_CPP_Class (Typ) then
null;
elsif Is_Tagged_Type (Typ) and then Tagged_Type_Expansion then
Instr :=
Make_OK_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Target),
Selector_Name =>
New_Reference_To
(First_Tag_Component (Base_Type (Typ)), Loc)),
Expression =>
Unchecked_Convert_To (RTE (RE_Tag),
New_Reference_To
(Node (First_Elmt (Access_Disp_Table (Base_Type (Typ)))),
Loc)));
Append_To (L, Instr);
-- Ada 2005 (AI-251): If the tagged type has been derived from
-- abstract interfaces we must also initialize the tags of the
-- secondary dispatch tables.
if Has_Interfaces (Base_Type (Typ)) then
Init_Secondary_Tags
(Typ => Base_Type (Typ),
Target => Target,
Stmts_List => L);
end if;
end if;
-- If the controllers have not been initialized yet (by lack of non-
-- discriminant components), let's do it now.
Generate_Finalization_Actions;
return L;
end Build_Record_Aggr_Code;
---------------------------------------
-- Collect_Initialization_Statements --
---------------------------------------
procedure Collect_Initialization_Statements
(Obj : Entity_Id;
N : Node_Id;
Node_After : Node_Id)
is
Loc : constant Source_Ptr := Sloc (N);
Init_Actions : constant List_Id := New_List;
Init_Node : Node_Id;
EA : Node_Id;
begin
-- Nothing to do if Obj is already frozen, as in this case we known we
-- won't need to move the initialization statements about later on.
if Is_Frozen (Obj) then
return;
end if;
Init_Node := N;
while Next (Init_Node) /= Node_After loop
Append_To (Init_Actions, Remove_Next (Init_Node));
end loop;
if not Is_Empty_List (Init_Actions) then
EA :=
Make_Expression_With_Actions (Loc,
Actions => Init_Actions,
Expression => Make_Null_Statement (Loc));
Insert_Action_After (Init_Node, EA);
Set_Initialization_Statements (Obj, EA);
end if;
end Collect_Initialization_Statements;
-------------------------------
-- Convert_Aggr_In_Allocator --
-------------------------------
procedure Convert_Aggr_In_Allocator
(Alloc : Node_Id;
Decl : Node_Id;
Aggr : Node_Id)
is
Loc : constant Source_Ptr := Sloc (Aggr);
Typ : constant Entity_Id := Etype (Aggr);
Temp : constant Entity_Id := Defining_Identifier (Decl);
Occ : constant Node_Id :=
Unchecked_Convert_To (Typ,
Make_Explicit_Dereference (Loc, New_Reference_To (Temp, Loc)));
begin
if Is_Array_Type (Typ) then
Convert_Array_Aggr_In_Allocator (Decl, Aggr, Occ);
elsif Has_Default_Init_Comps (Aggr) then
declare
L : constant List_Id := New_List;
Init_Stmts : List_Id;
begin
Init_Stmts := Late_Expansion (Aggr, Typ, Occ);
if Has_Task (Typ) then
Build_Task_Allocate_Block_With_Init_Stmts (L, Aggr, Init_Stmts);
Insert_Actions (Alloc, L);
else
Insert_Actions (Alloc, Init_Stmts);
end if;
end;
else
Insert_Actions (Alloc, Late_Expansion (Aggr, Typ, Occ));
end if;
end Convert_Aggr_In_Allocator;
--------------------------------
-- Convert_Aggr_In_Assignment --
--------------------------------
procedure Convert_Aggr_In_Assignment (N : Node_Id) is
Aggr : Node_Id := Expression (N);
Typ : constant Entity_Id := Etype (Aggr);
Occ : constant Node_Id := New_Copy_Tree (Name (N));
begin
if Nkind (Aggr) = N_Qualified_Expression then
Aggr := Expression (Aggr);
end if;
Insert_Actions_After (N, Late_Expansion (Aggr, Typ, Occ));
end Convert_Aggr_In_Assignment;
---------------------------------
-- Convert_Aggr_In_Object_Decl --
---------------------------------
procedure Convert_Aggr_In_Object_Decl (N : Node_Id) is
Obj : constant Entity_Id := Defining_Identifier (N);
Aggr : Node_Id := Expression (N);
Loc : constant Source_Ptr := Sloc (Aggr);
Typ : constant Entity_Id := Etype (Aggr);
Occ : constant Node_Id := New_Occurrence_Of (Obj, Loc);
function Discriminants_Ok return Boolean;
-- If the object type is constrained, the discriminants in the
-- aggregate must be checked against the discriminants of the subtype.
-- This cannot be done using Apply_Discriminant_Checks because after
-- expansion there is no aggregate left to check.
----------------------
-- Discriminants_Ok --
----------------------
function Discriminants_Ok return Boolean is
Cond : Node_Id := Empty;
Check : Node_Id;
D : Entity_Id;
Disc1 : Elmt_Id;
Disc2 : Elmt_Id;
Val1 : Node_Id;
Val2 : Node_Id;
begin
D := First_Discriminant (Typ);
Disc1 := First_Elmt (Discriminant_Constraint (Typ));
Disc2 := First_Elmt (Discriminant_Constraint (Etype (Obj)));
while Present (Disc1) and then Present (Disc2) loop
Val1 := Node (Disc1);
Val2 := Node (Disc2);
if not Is_OK_Static_Expression (Val1)
or else not Is_OK_Static_Expression (Val2)
then
Check := Make_Op_Ne (Loc,
Left_Opnd => Duplicate_Subexpr (Val1),
Right_Opnd => Duplicate_Subexpr (Val2));
if No (Cond) then
Cond := Check;
else
Cond := Make_Or_Else (Loc,
Left_Opnd => Cond,
Right_Opnd => Check);
end if;
elsif Expr_Value (Val1) /= Expr_Value (Val2) then
Apply_Compile_Time_Constraint_Error (Aggr,
Msg => "incorrect value for discriminant&??",
Reason => CE_Discriminant_Check_Failed,
Ent => D);
return False;
end if;
Next_Discriminant (D);
Next_Elmt (Disc1);
Next_Elmt (Disc2);
end loop;
-- If any discriminant constraint is non-static, emit a check
if Present (Cond) then
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
Reason => CE_Discriminant_Check_Failed));
end if;
return True;
end Discriminants_Ok;
-- Start of processing for Convert_Aggr_In_Object_Decl
begin
Set_Assignment_OK (Occ);
if Nkind (Aggr) = N_Qualified_Expression then
Aggr := Expression (Aggr);
end if;
if Has_Discriminants (Typ)
and then Typ /= Etype (Obj)
and then Is_Constrained (Etype (Obj))
and then not Discriminants_Ok
then
return;
end if;
-- If the context is an extended return statement, it has its own
-- finalization machinery (i.e. works like a transient scope) and
-- we do not want to create an additional one, because objects on
-- the finalization list of the return must be moved to the caller's
-- finalization list to complete the return.
-- However, if the aggregate is limited, it is built in place, and the
-- controlled components are not assigned to intermediate temporaries
-- so there is no need for a transient scope in this case either.
if Requires_Transient_Scope (Typ)
and then Ekind (Current_Scope) /= E_Return_Statement
and then not Is_Limited_Type (Typ)
then
Establish_Transient_Scope
(Aggr,
Sec_Stack =>
Is_Controlled (Typ) or else Has_Controlled_Component (Typ));
end if;
declare
Node_After : constant Node_Id := Next (N);
begin
Insert_Actions_After (N, Late_Expansion (Aggr, Typ, Occ));
Collect_Initialization_Statements (Obj, N, Node_After);
end;
Set_No_Initialization (N);
Initialize_Discriminants (N, Typ);
end Convert_Aggr_In_Object_Decl;
-------------------------------------
-- Convert_Array_Aggr_In_Allocator --
-------------------------------------
procedure Convert_Array_Aggr_In_Allocator
(Decl : Node_Id;
Aggr : Node_Id;
Target : Node_Id)
is
Aggr_Code : List_Id;
Typ : constant Entity_Id := Etype (Aggr);
Ctyp : constant Entity_Id := Component_Type (Typ);
begin
-- The target is an explicit dereference of the allocated object.
-- Generate component assignments to it, as for an aggregate that
-- appears on the right-hand side of an assignment statement.
Aggr_Code :=
Build_Array_Aggr_Code (Aggr,
Ctype => Ctyp,
Index => First_Index (Typ),
Into => Target,
Scalar_Comp => Is_Scalar_Type (Ctyp));
Insert_Actions_After (Decl, Aggr_Code);
end Convert_Array_Aggr_In_Allocator;
----------------------------
-- Convert_To_Assignments --
----------------------------
procedure Convert_To_Assignments (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
T : Entity_Id;
Temp : Entity_Id;
Instr : Node_Id;
Target_Expr : Node_Id;
Parent_Kind : Node_Kind;
Unc_Decl : Boolean := False;
Parent_Node : Node_Id;
begin
pragma Assert (not Is_Static_Dispatch_Table_Aggregate (N));
pragma Assert (Is_Record_Type (Typ));
Parent_Node := Parent (N);
Parent_Kind := Nkind (Parent_Node);
if Parent_Kind = N_Qualified_Expression then
-- Check if we are in a unconstrained declaration because in this
-- case the current delayed expansion mechanism doesn't work when
-- the declared object size depend on the initializing expr.
begin
Parent_Node := Parent (Parent_Node);
Parent_Kind := Nkind (Parent_Node);
if Parent_Kind = N_Object_Declaration then
Unc_Decl :=
not Is_Entity_Name (Object_Definition (Parent_Node))
or else Has_Discriminants
(Entity (Object_Definition (Parent_Node)))
or else Is_Class_Wide_Type
(Entity (Object_Definition (Parent_Node)));
end if;
end;
end if;
-- Just set the Delay flag in the cases where the transformation will be
-- done top down from above.
if False
-- Internal aggregate (transformed when expanding the parent)
or else Parent_Kind = N_Aggregate
or else Parent_Kind = N_Extension_Aggregate
or else Parent_Kind = N_Component_Association
-- Allocator (see Convert_Aggr_In_Allocator)
or else Parent_Kind = N_Allocator
-- Object declaration (see Convert_Aggr_In_Object_Decl)
or else (Parent_Kind = N_Object_Declaration and then not Unc_Decl)
-- Safe assignment (see Convert_Aggr_Assignments). So far only the
-- assignments in init procs are taken into account.
or else (Parent_Kind = N_Assignment_Statement
and then Inside_Init_Proc)
-- (Ada 2005) An inherently limited type in a return statement,
-- which will be handled in a build-in-place fashion, and may be
-- rewritten as an extended return and have its own finalization
-- machinery. In the case of a simple return, the aggregate needs
-- to be delayed until the scope for the return statement has been
-- created, so that any finalization chain will be associated with
-- that scope. For extended returns, we delay expansion to avoid the
-- creation of an unwanted transient scope that could result in
-- premature finalization of the return object (which is built in
-- in place within the caller's scope).
or else
(Is_Immutably_Limited_Type (Typ)
and then
(Nkind (Parent (Parent_Node)) = N_Extended_Return_Statement
or else Nkind (Parent_Node) = N_Simple_Return_Statement))
then
Set_Expansion_Delayed (N);
return;
end if;
if Requires_Transient_Scope (Typ) then
Establish_Transient_Scope
(N, Sec_Stack =>
Is_Controlled (Typ) or else Has_Controlled_Component (Typ));
end if;
-- If the aggregate is non-limited, create a temporary. If it is limited
-- and the context is an assignment, this is a subaggregate for an
-- enclosing aggregate being expanded. It must be built in place, so use
-- the target of the current assignment.
if Is_Limited_Type (Typ)
and then Nkind (Parent (N)) = N_Assignment_Statement
then
Target_Expr := New_Copy_Tree (Name (Parent (N)));
Insert_Actions (Parent (N),
Build_Record_Aggr_Code (N, Typ, Target_Expr));
Rewrite (Parent (N), Make_Null_Statement (Loc));
else
Temp := Make_Temporary (Loc, 'A', N);
-- If the type inherits unknown discriminants, use the view with
-- known discriminants if available.
if Has_Unknown_Discriminants (Typ)
and then Present (Underlying_Record_View (Typ))
then
T := Underlying_Record_View (Typ);
else
T := Typ;
end if;
Instr :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition => New_Occurrence_Of (T, Loc));
Set_No_Initialization (Instr);
Insert_Action (N, Instr);
Initialize_Discriminants (Instr, T);
Target_Expr := New_Occurrence_Of (Temp, Loc);
Insert_Actions (N, Build_Record_Aggr_Code (N, T, Target_Expr));
Rewrite (N, New_Occurrence_Of (Temp, Loc));
Analyze_And_Resolve (N, T);
end if;
end Convert_To_Assignments;
---------------------------
-- Convert_To_Positional --
---------------------------
procedure Convert_To_Positional
(N : Node_Id;
Max_Others_Replicate : Nat := 5;
Handle_Bit_Packed : Boolean := False)
is
Typ : constant Entity_Id := Etype (N);
Static_Components : Boolean := True;
procedure Check_Static_Components;
-- Check whether all components of the aggregate are compile-time known
-- values, and can be passed as is to the back-end without further
-- expansion.
function Flatten
(N : Node_Id;
Ix : Node_Id;
Ixb : Node_Id) return Boolean;
-- Convert the aggregate into a purely positional form if possible. On
-- entry the bounds of all dimensions are known to be static, and the
-- total number of components is safe enough to expand.
function Is_Flat (N : Node_Id; Dims : Int) return Boolean;
-- Return True iff the array N is flat (which is not trivial in the case
-- of multidimensional aggregates).
-----------------------------
-- Check_Static_Components --
-----------------------------
procedure Check_Static_Components is
Expr : Node_Id;
begin
Static_Components := True;
if Nkind (N) = N_String_Literal then
null;
elsif Present (Expressions (N)) then
Expr := First (Expressions (N));
while Present (Expr) loop
if Nkind (Expr) /= N_Aggregate
or else not Compile_Time_Known_Aggregate (Expr)
or else Expansion_Delayed (Expr)
then
Static_Components := False;
exit;
end if;
Next (Expr);
end loop;
end if;
if Nkind (N) = N_Aggregate
and then Present (Component_Associations (N))
then
Expr := First (Component_Associations (N));
while Present (Expr) loop
if Nkind_In (Expression (Expr), N_Integer_Literal,
N_Real_Literal)
then
null;
elsif Is_Entity_Name (Expression (Expr))
and then Present (Entity (Expression (Expr)))
and then Ekind (Entity (Expression (Expr))) =
E_Enumeration_Literal
then
null;
elsif Nkind (Expression (Expr)) /= N_Aggregate
or else not Compile_Time_Known_Aggregate (Expression (Expr))
or else Expansion_Delayed (Expression (Expr))
then
Static_Components := False;
exit;
end if;
Next (Expr);
end loop;
end if;
end Check_Static_Components;
-------------
-- Flatten --
-------------
function Flatten
(N : Node_Id;
Ix : Node_Id;
Ixb : Node_Id) return Boolean
is
Loc : constant Source_Ptr := Sloc (N);
Blo : constant Node_Id := Type_Low_Bound (Etype (Ixb));
Lo : constant Node_Id := Type_Low_Bound (Etype (Ix));
Hi : constant Node_Id := Type_High_Bound (Etype (Ix));
Lov : Uint;
Hiv : Uint;
Others_Present : Boolean := False;
begin
if Nkind (Original_Node (N)) = N_String_Literal then
return True;
end if;
if not Compile_Time_Known_Value (Lo)
or else not Compile_Time_Known_Value (Hi)
then
return False;
end if;
Lov := Expr_Value (Lo);
Hiv := Expr_Value (Hi);
-- Check if there is an others choice
if Present (Component_Associations (N)) then
declare
Assoc : Node_Id;
Choice : Node_Id;
begin
Assoc := First (Component_Associations (N));
while Present (Assoc) loop
-- If this is a box association, flattening is in general
-- not possible because at this point we cannot tell if the
-- default is static or even exists.
if Box_Present (Assoc) then
return False;
end if;
Choice := First (Choices (Assoc));
while Present (Choice) loop
if Nkind (Choice) = N_Others_Choice then
Others_Present := True;
end if;
Next (Choice);
end loop;
Next (Assoc);
end loop;
end;
end if;
-- If the low bound is not known at compile time and others is not
-- present we can proceed since the bounds can be obtained from the
-- aggregate.
-- Note: This case is required in VM platforms since their backends
-- normalize array indexes in the range 0 .. N-1. Hence, if we do
-- not flat an array whose bounds cannot be obtained from the type
-- of the index the backend has no way to properly generate the code.
-- See ACATS c460010 for an example.
if Hiv < Lov
or else (not Compile_Time_Known_Value (Blo)
and then Others_Present)
then
return False;
end if;
-- Determine if set of alternatives is suitable for conversion and
-- build an array containing the values in sequence.
declare
Vals : array (UI_To_Int (Lov) .. UI_To_Int (Hiv))
of Node_Id := (others => Empty);
-- The values in the aggregate sorted appropriately
Vlist : List_Id;
-- Same data as Vals in list form
Rep_Count : Nat;
-- Used to validate Max_Others_Replicate limit
Elmt : Node_Id;
Num : Int := UI_To_Int (Lov);
Choice_Index : Int;
Choice : Node_Id;
Lo, Hi : Node_Id;
begin
if Present (Expressions (N)) then
Elmt := First (Expressions (N));
while Present (Elmt) loop
if Nkind (Elmt) = N_Aggregate
and then Present (Next_Index (Ix))
and then
not Flatten (Elmt, Next_Index (Ix), Next_Index (Ixb))
then
return False;
end if;
Vals (Num) := Relocate_Node (Elmt);
Num := Num + 1;
Next (Elmt);
end loop;
end if;
if No (Component_Associations (N)) then
return True;
end if;
Elmt := First (Component_Associations (N));
if Nkind (Expression (Elmt)) = N_Aggregate then
if Present (Next_Index (Ix))
and then
not Flatten
(Expression (Elmt), Next_Index (Ix), Next_Index (Ixb))
then
return False;
end if;
end if;
Component_Loop : while Present (Elmt) loop
Choice := First (Choices (Elmt));
Choice_Loop : while Present (Choice) loop
-- If we have an others choice, fill in the missing elements
-- subject to the limit established by Max_Others_Replicate.
if Nkind (Choice) = N_Others_Choice then
Rep_Count := 0;
for J in Vals'Range loop
if No (Vals (J)) then
Vals (J) := New_Copy_Tree (Expression (Elmt));
Rep_Count := Rep_Count + 1;
-- Check for maximum others replication. Note that
-- we skip this test if either of the restrictions
-- No_Elaboration_Code or No_Implicit_Loops is
-- active, if this is a preelaborable unit or
-- a predefined unit, or if the unit must be
-- placed in data memory. This also ensures that
-- predefined units get the same level of constant
-- folding in Ada 95 and Ada 2005, where their
-- categorization has changed.
declare
P : constant Entity_Id :=
Cunit_Entity (Current_Sem_Unit);
begin
-- Check if duplication OK and if so continue
-- processing.
if Restriction_Active (No_Elaboration_Code)
or else Restriction_Active (No_Implicit_Loops)
or else
(Ekind (Current_Scope) = E_Package
and then
Static_Elaboration_Desired
(Current_Scope))
or else Is_Preelaborated (P)
or else (Ekind (P) = E_Package_Body
and then
Is_Preelaborated (Spec_Entity (P)))
or else
Is_Predefined_File_Name
(Unit_File_Name (Get_Source_Unit (P)))
then
null;
-- If duplication not OK, then we return False
-- if the replication count is too high
elsif Rep_Count > Max_Others_Replicate then
return False;
-- Continue on if duplication not OK, but the
-- replication count is not excessive.
else
null;
end if;
end;
end if;
end loop;
exit Component_Loop;
-- Case of a subtype mark, identifier or expanded name
elsif Is_Entity_Name (Choice)
and then Is_Type (Entity (Choice))
then
Lo := Type_Low_Bound (Etype (Choice));
Hi := Type_High_Bound (Etype (Choice));
-- Case of subtype indication
elsif Nkind (Choice) = N_Subtype_Indication then
Lo := Low_Bound (Range_Expression (Constraint (Choice)));
Hi := High_Bound (Range_Expression (Constraint (Choice)));
-- Case of a range
elsif Nkind (Choice) = N_Range then
Lo := Low_Bound (Choice);
Hi := High_Bound (Choice);
-- Normal subexpression case
else pragma Assert (Nkind (Choice) in N_Subexpr);
if not Compile_Time_Known_Value (Choice) then
return False;
else
Choice_Index := UI_To_Int (Expr_Value (Choice));
if Choice_Index in Vals'Range then
Vals (Choice_Index) :=
New_Copy_Tree (Expression (Elmt));
goto Continue;
else
-- Choice is statically out-of-range, will be
-- rewritten to raise Constraint_Error.
return False;
end if;
end if;
end if;
-- Range cases merge with Lo,Hi set
if not Compile_Time_Known_Value (Lo)
or else
not Compile_Time_Known_Value (Hi)
then
return False;
else
for J in UI_To_Int (Expr_Value (Lo)) ..
UI_To_Int (Expr_Value (Hi))
loop
Vals (J) := New_Copy_Tree (Expression (Elmt));
end loop;
end if;
<<Continue>>
Next (Choice);
end loop Choice_Loop;
Next (Elmt);
end loop Component_Loop;
-- If we get here the conversion is possible
Vlist := New_List;
for J in Vals'Range loop
Append (Vals (J), Vlist);
end loop;
Rewrite (N, Make_Aggregate (Loc, Expressions => Vlist));
Set_Aggregate_Bounds (N, Aggregate_Bounds (Original_Node (N)));
return True;
end;
end Flatten;
-------------
-- Is_Flat --
-------------
function Is_Flat (N : Node_Id; Dims : Int) return Boolean is
Elmt : Node_Id;
begin
if Dims = 0 then
return True;
elsif Nkind (N) = N_Aggregate then
if Present (Component_Associations (N)) then
return False;
else
Elmt := First (Expressions (N));
while Present (Elmt) loop
if not Is_Flat (Elmt, Dims - 1) then
return False;
end if;
Next (Elmt);
end loop;
return True;
end if;
else
return True;
end if;
end Is_Flat;
-- Start of processing for Convert_To_Positional
begin
-- Ada 2005 (AI-287): Do not convert in case of default initialized
-- components because in this case will need to call the corresponding
-- IP procedure.
if Has_Default_Init_Comps (N) then
return;
end if;
if Is_Flat (N, Number_Dimensions (Typ)) then
return;
end if;
if Is_Bit_Packed_Array (Typ)
and then not Handle_Bit_Packed
then
return;
end if;
-- Do not convert to positional if controlled components are involved
-- since these require special processing
if Has_Controlled_Component (Typ) then
return;
end if;
Check_Static_Components;
-- If the size is known, or all the components are static, try to
-- build a fully positional aggregate.
-- The size of the type may not be known for an aggregate with
-- discriminated array components, but if the components are static
-- it is still possible to verify statically that the length is
-- compatible with the upper bound of the type, and therefore it is
-- worth flattening such aggregates as well.
-- For now the back-end expands these aggregates into individual
-- assignments to the target anyway, but it is conceivable that
-- it will eventually be able to treat such aggregates statically???
if Aggr_Size_OK (N, Typ)
and then Flatten (N, First_Index (Typ), First_Index (Base_Type (Typ)))
then
if Static_Components then
Set_Compile_Time_Known_Aggregate (N);
Set_Expansion_Delayed (N, False);
end if;
Analyze_And_Resolve (N, Typ);
end if;
-- Is Static_Eaboration_Desired has been specified, diagnose aggregates
-- that will still require initialization code.
if (Ekind (Current_Scope) = E_Package
and then Static_Elaboration_Desired (Current_Scope))
and then Nkind (Parent (N)) = N_Object_Declaration
then
declare
Expr : Node_Id;
begin
if Nkind (N) = N_Aggregate and then Present (Expressions (N)) then
Expr := First (Expressions (N));
while Present (Expr) loop
if Nkind_In (Expr, N_Integer_Literal, N_Real_Literal)
or else
(Is_Entity_Name (Expr)
and then Ekind (Entity (Expr)) = E_Enumeration_Literal)
then
null;
else
Error_Msg_N
("non-static object requires elaboration code??", N);
exit;
end if;
Next (Expr);
end loop;
if Present (Component_Associations (N)) then
Error_Msg_N ("object requires elaboration code??", N);
end if;
end if;
end;
end if;
end Convert_To_Positional;
----------------------------
-- Expand_Array_Aggregate --
----------------------------
-- Array aggregate expansion proceeds as follows:
-- 1. If requested we generate code to perform all the array aggregate
-- bound checks, specifically
-- (a) Check that the index range defined by aggregate bounds is
-- compatible with corresponding index subtype.
-- (b) If an others choice is present check that no aggregate
-- index is outside the bounds of the index constraint.
-- (c) For multidimensional arrays make sure that all subaggregates
-- corresponding to the same dimension have the same bounds.
-- 2. Check for packed array aggregate which can be converted to a
-- constant so that the aggregate disappeares completely.
-- 3. Check case of nested aggregate. Generally nested aggregates are
-- handled during the processing of the parent aggregate.
-- 4. Check if the aggregate can be statically processed. If this is the
-- case pass it as is to Gigi. Note that a necessary condition for
-- static processing is that the aggregate be fully positional.
-- 5. If in place aggregate expansion is possible (i.e. no need to create
-- a temporary) then mark the aggregate as such and return. Otherwise
-- create a new temporary and generate the appropriate initialization
-- code.
procedure Expand_Array_Aggregate (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
Ctyp : constant Entity_Id := Component_Type (Typ);
-- Typ is the correct constrained array subtype of the aggregate
-- Ctyp is the corresponding component type.
Aggr_Dimension : constant Pos := Number_Dimensions (Typ);
-- Number of aggregate index dimensions
Aggr_Low : array (1 .. Aggr_Dimension) of Node_Id;
Aggr_High : array (1 .. Aggr_Dimension) of Node_Id;
-- Low and High bounds of the constraint for each aggregate index
Aggr_Index_Typ : array (1 .. Aggr_Dimension) of Entity_Id;
-- The type of each index
Maybe_In_Place_OK : Boolean;
-- If the type is neither controlled nor packed and the aggregate
-- is the expression in an assignment, assignment in place may be
-- possible, provided other conditions are met on the LHS.
Others_Present : array (1 .. Aggr_Dimension) of Boolean :=
(others => False);
-- If Others_Present (J) is True, then there is an others choice
-- in one of the sub-aggregates of N at dimension J.
procedure Build_Constrained_Type (Positional : Boolean);
-- If the subtype is not static or unconstrained, build a constrained
-- type using the computable sizes of the aggregate and its sub-
-- aggregates.
procedure Check_Bounds (Aggr_Bounds : Node_Id; Index_Bounds : Node_Id);
-- Checks that the bounds of Aggr_Bounds are within the bounds defined
-- by Index_Bounds.
procedure Check_Same_Aggr_Bounds (Sub_Aggr : Node_Id; Dim : Pos);
-- Checks that in a multi-dimensional array aggregate all subaggregates
-- corresponding to the same dimension have the same bounds.
-- Sub_Aggr is an array sub-aggregate. Dim is the dimension
-- corresponding to the sub-aggregate.
procedure Compute_Others_Present (Sub_Aggr : Node_Id; Dim : Pos);
-- Computes the values of array Others_Present. Sub_Aggr is the
-- array sub-aggregate we start the computation from. Dim is the
-- dimension corresponding to the sub-aggregate.
function In_Place_Assign_OK return Boolean;
-- Simple predicate to determine whether an aggregate assignment can
-- be done in place, because none of the new values can depend on the
-- components of the target of the assignment.
procedure Others_Check (Sub_Aggr : Node_Id; Dim : Pos);
-- Checks that if an others choice is present in any sub-aggregate no
-- aggregate index is outside the bounds of the index constraint.
-- Sub_Aggr is an array sub-aggregate. Dim is the dimension
-- corresponding to the sub-aggregate.
function Safe_Left_Hand_Side (N : Node_Id) return Boolean;
-- In addition to Maybe_In_Place_OK, in order for an aggregate to be
-- built directly into the target of the assignment it must be free
-- of side-effects.
----------------------------
-- Build_Constrained_Type --
----------------------------
procedure Build_Constrained_Type (Positional : Boolean) is
Loc : constant Source_Ptr := Sloc (N);
Agg_Type : constant Entity_Id := Make_Temporary (Loc, 'A');
Comp : Node_Id;
Decl : Node_Id;
Typ : constant Entity_Id := Etype (N);
Indexes : constant List_Id := New_List;
Num : Int;
Sub_Agg : Node_Id;
begin
-- If the aggregate is purely positional, all its subaggregates
-- have the same size. We collect the dimensions from the first
-- subaggregate at each level.
if Positional then
Sub_Agg := N;
for D in 1 .. Number_Dimensions (Typ) loop
Sub_Agg := First (Expressions (Sub_Agg));
Comp := Sub_Agg;
Num := 0;
while Present (Comp) loop
Num := Num + 1;
Next (Comp);
end loop;
Append_To (Indexes,
Make_Range (Loc,
Low_Bound => Make_Integer_Literal (Loc, 1),
High_Bound => Make_Integer_Literal (Loc, Num)));
end loop;
else
-- We know the aggregate type is unconstrained and the aggregate
-- is not processable by the back end, therefore not necessarily
-- positional. Retrieve each dimension bounds (computed earlier).
for D in 1 .. Number_Dimensions (Typ) loop
Append (
Make_Range (Loc,
Low_Bound => Aggr_Low (D),
High_Bound => Aggr_High (D)),
Indexes);
end loop;
end if;
Decl :=
Make_Full_Type_Declaration (Loc,
Defining_Identifier => Agg_Type,
Type_Definition =>
Make_Constrained_Array_Definition (Loc,
Discrete_Subtype_Definitions => Indexes,
Component_Definition =>
Make_Component_Definition (Loc,
Aliased_Present => False,
Subtype_Indication =>
New_Occurrence_Of (Component_Type (Typ), Loc))));
Insert_Action (N, Decl);
Analyze (Decl);
Set_Etype (N, Agg_Type);
Set_Is_Itype (Agg_Type);
Freeze_Itype (Agg_Type, N);
end Build_Constrained_Type;
------------------
-- Check_Bounds --
------------------
procedure Check_Bounds (Aggr_Bounds : Node_Id; Index_Bounds : Node_Id) is
Aggr_Lo : Node_Id;
Aggr_Hi : Node_Id;
Ind_Lo : Node_Id;
Ind_Hi : Node_Id;
Cond : Node_Id := Empty;
begin
Get_Index_Bounds (Aggr_Bounds, Aggr_Lo, Aggr_Hi);
Get_Index_Bounds (Index_Bounds, Ind_Lo, Ind_Hi);
-- Generate the following test:
--
-- [constraint_error when
-- Aggr_Lo <= Aggr_Hi and then
-- (Aggr_Lo < Ind_Lo or else Aggr_Hi > Ind_Hi)]
-- As an optimization try to see if some tests are trivially vacuous
-- because we are comparing an expression against itself.
if Aggr_Lo = Ind_Lo and then Aggr_Hi = Ind_Hi then
Cond := Empty;
elsif Aggr_Hi = Ind_Hi then
Cond :=
Make_Op_Lt (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Lo),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Ind_Lo));
elsif Aggr_Lo = Ind_Lo then
Cond :=
Make_Op_Gt (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Hi),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Ind_Hi));
else
Cond :=
Make_Or_Else (Loc,
Left_Opnd =>
Make_Op_Lt (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Lo),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Ind_Lo)),
Right_Opnd =>
Make_Op_Gt (Loc,
Left_Opnd => Duplicate_Subexpr (Aggr_Hi),
Right_Opnd => Duplicate_Subexpr (Ind_Hi)));
end if;
if Present (Cond) then
Cond :=
Make_And_Then (Loc,
Left_Opnd =>
Make_Op_Le (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Lo),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Hi)),
Right_Opnd => Cond);
Set_Analyzed (Left_Opnd (Left_Opnd (Cond)), False);
Set_Analyzed (Right_Opnd (Left_Opnd (Cond)), False);
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
Reason => CE_Length_Check_Failed));
end if;
end Check_Bounds;
----------------------------
-- Check_Same_Aggr_Bounds --
----------------------------
procedure Check_Same_Aggr_Bounds (Sub_Aggr : Node_Id; Dim : Pos) is
Sub_Lo : constant Node_Id := Low_Bound (Aggregate_Bounds (Sub_Aggr));
Sub_Hi : constant Node_Id := High_Bound (Aggregate_Bounds (Sub_Aggr));
-- The bounds of this specific sub-aggregate
Aggr_Lo : constant Node_Id := Aggr_Low (Dim);
Aggr_Hi : constant Node_Id := Aggr_High (Dim);
-- The bounds of the aggregate for this dimension
Ind_Typ : constant Entity_Id := Aggr_Index_Typ (Dim);
-- The index type for this dimension.xxx
Cond : Node_Id := Empty;
Assoc : Node_Id;
Expr : Node_Id;
begin
-- If index checks are on generate the test
-- [constraint_error when
-- Aggr_Lo /= Sub_Lo or else Aggr_Hi /= Sub_Hi]
-- As an optimization try to see if some tests are trivially vacuos
-- because we are comparing an expression against itself. Also for
-- the first dimension the test is trivially vacuous because there
-- is just one aggregate for dimension 1.
if Index_Checks_Suppressed (Ind_Typ) then
Cond := Empty;
elsif Dim = 1
or else (Aggr_Lo = Sub_Lo and then Aggr_Hi = Sub_Hi)
then
Cond := Empty;
elsif Aggr_Hi = Sub_Hi then
Cond :=
Make_Op_Ne (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Lo),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Sub_Lo));
elsif Aggr_Lo = Sub_Lo then
Cond :=
Make_Op_Ne (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Hi),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Sub_Hi));
else
Cond :=
Make_Or_Else (Loc,
Left_Opnd =>
Make_Op_Ne (Loc,
Left_Opnd => Duplicate_Subexpr_Move_Checks (Aggr_Lo),
Right_Opnd => Duplicate_Subexpr_Move_Checks (Sub_Lo)),
Right_Opnd =>
Make_Op_Ne (Loc,
Left_Opnd => Duplicate_Subexpr (Aggr_Hi),
Right_Opnd => Duplicate_Subexpr (Sub_Hi)));
end if;
if Present (Cond) then
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
Reason => CE_Length_Check_Failed));
end if;
-- Now look inside the sub-aggregate to see if there is more work
if Dim < Aggr_Dimension then
-- Process positional components
if Present (Expressions (Sub_Aggr)) then
Expr := First (Expressions (Sub_Aggr));
while Present (Expr) loop
Check_Same_Aggr_Bounds (Expr, Dim + 1);
Next (Expr);
end loop;
end if;
-- Process component associations
if Present (Component_Associations (Sub_Aggr)) then
Assoc := First (Component_Associations (Sub_Aggr));
while Present (Assoc) loop
Expr := Expression (Assoc);
Check_Same_Aggr_Bounds (Expr, Dim + 1);
Next (Assoc);
end loop;
end if;
end if;
end Check_Same_Aggr_Bounds;
----------------------------
-- Compute_Others_Present --
----------------------------
procedure Compute_Others_Present (Sub_Aggr : Node_Id; Dim : Pos) is
Assoc : Node_Id;
Expr : Node_Id;
begin
if Present (Component_Associations (Sub_Aggr)) then
Assoc := Last (Component_Associations (Sub_Aggr));
if Nkind (First (Choices (Assoc))) = N_Others_Choice then
Others_Present (Dim) := True;
end if;
end if;
-- Now look inside the sub-aggregate to see if there is more work
if Dim < Aggr_Dimension then
-- Process positional components
if Present (Expressions (Sub_Aggr)) then
Expr := First (Expressions (Sub_Aggr));
while Present (Expr) loop
Compute_Others_Present (Expr, Dim + 1);
Next (Expr);
end loop;
end if;
-- Process component associations
if Present (Component_Associations (Sub_Aggr)) then
Assoc := First (Component_Associations (Sub_Aggr));
while Present (Assoc) loop
Expr := Expression (Assoc);
Compute_Others_Present (Expr, Dim + 1);
Next (Assoc);
end loop;
end if;
end if;
end Compute_Others_Present;
------------------------
-- In_Place_Assign_OK --
------------------------
function In_Place_Assign_OK return Boolean is
Aggr_In : Node_Id;
Aggr_Lo : Node_Id;
Aggr_Hi : Node_Id;
Obj_In : Node_Id;
Obj_Lo : Node_Id;
Obj_Hi : Node_Id;
function Safe_Aggregate (Aggr : Node_Id) return Boolean;
-- Check recursively that each component of a (sub)aggregate does
-- not depend on the variable being assigned to.
function Safe_Component (Expr : Node_Id) return Boolean;
-- Verify that an expression cannot depend on the variable being
-- assigned to. Room for improvement here (but less than before).
--------------------
-- Safe_Aggregate --
--------------------
function Safe_Aggregate (Aggr : Node_Id) return Boolean is
Expr : Node_Id;
begin
if Present (Expressions (Aggr)) then
Expr := First (Expressions (Aggr));
while Present (Expr) loop
if Nkind (Expr) = N_Aggregate then
if not Safe_Aggregate (Expr) then
return False;
end if;
elsif not Safe_Component (Expr) then
return False;
end if;
Next (Expr);
end loop;
end if;
if Present (Component_Associations (Aggr)) then
Expr := First (Component_Associations (Aggr));
while Present (Expr) loop
if Nkind (Expression (Expr)) = N_Aggregate then
if not Safe_Aggregate (Expression (Expr)) then
return False;
end if;
-- If association has a box, no way to determine yet
-- whether default can be assigned in place.
elsif Box_Present (Expr) then
return False;
elsif not Safe_Component (Expression (Expr)) then
return False;
end if;
Next (Expr);
end loop;
end if;
return True;
end Safe_Aggregate;
--------------------
-- Safe_Component --
--------------------
function Safe_Component (Expr : Node_Id) return Boolean is
Comp : Node_Id := Expr;
function Check_Component (Comp : Node_Id) return Boolean;
-- Do the recursive traversal, after copy
---------------------
-- Check_Component --
---------------------
function Check_Component (Comp : Node_Id) return Boolean is
begin
if Is_Overloaded (Comp) then
return False;
end if;
return Compile_Time_Known_Value (Comp)
or else (Is_Entity_Name (Comp)
and then Present (Entity (Comp))
and then No (Renamed_Object (Entity (Comp))))
or else (Nkind (Comp) = N_Attribute_Reference
and then Check_Component (Prefix (Comp)))
or else (Nkind (Comp) in N_Binary_Op
and then Check_Component (Left_Opnd (Comp))
and then Check_Component (Right_Opnd (Comp)))
or else (Nkind (Comp) in N_Unary_Op
and then Check_Component (Right_Opnd (Comp)))
or else (Nkind (Comp) = N_Selected_Component
and then Check_Component (Prefix (Comp)))
or else (Nkind (Comp) = N_Unchecked_Type_Conversion
and then Check_Component (Expression (Comp)));
end Check_Component;
-- Start of processing for Safe_Component
begin
-- If the component appears in an association that may
-- correspond to more than one element, it is not analyzed
-- before the expansion into assignments, to avoid side effects.
-- We analyze, but do not resolve the copy, to obtain sufficient
-- entity information for the checks that follow. If component is
-- overloaded we assume an unsafe function call.
if not Analyzed (Comp) then
if Is_Overloaded (Expr) then
return False;
elsif Nkind (Expr) = N_Aggregate
and then not Is_Others_Aggregate (Expr)
then
return False;
elsif Nkind (Expr) = N_Allocator then
-- For now, too complex to analyze
return False;
end if;
Comp := New_Copy_Tree (Expr);
Set_Parent (Comp, Parent (Expr));
Analyze (Comp);
end if;
if Nkind (Comp) = N_Aggregate then
return Safe_Aggregate (Comp);
else
return Check_Component (Comp);
end if;
end Safe_Component;
-- Start of processing for In_Place_Assign_OK
begin
if Present (Component_Associations (N)) then
-- On assignment, sliding can take place, so we cannot do the
-- assignment in place unless the bounds of the aggregate are
-- statically equal to those of the target.
-- If the aggregate is given by an others choice, the bounds
-- are derived from the left-hand side, and the assignment is
-- safe if the expression is.
if Is_Others_Aggregate (N) then
return
Safe_Component
(Expression (First (Component_Associations (N))));
end if;
Aggr_In := First_Index (Etype (N));
if Nkind (Parent (N)) = N_Assignment_Statement then
Obj_In := First_Index (Etype (Name (Parent (N))));
else
-- Context is an allocator. Check bounds of aggregate
-- against given type in qualified expression.
pragma Assert (Nkind (Parent (Parent (N))) = N_Allocator);
Obj_In :=
First_Index (Etype (Entity (Subtype_Mark (Parent (N)))));
end if;
while Present (Aggr_In) loop
Get_Index_Bounds (Aggr_In, Aggr_Lo, Aggr_Hi);
Get_Index_Bounds (Obj_In, Obj_Lo, Obj_Hi);
if not Compile_Time_Known_Value (Aggr_Lo)
or else not Compile_Time_Known_Value (Aggr_Hi)
or else not Compile_Time_Known_Value (Obj_Lo)
or else not Compile_Time_Known_Value (Obj_Hi)
or else Expr_Value (Aggr_Lo) /= Expr_Value (Obj_Lo)
or else Expr_Value (Aggr_Hi) /= Expr_Value (Obj_Hi)
then
return False;
end if;
Next_Index (Aggr_In);
Next_Index (Obj_In);
end loop;
end if;
-- Now check the component values themselves
return Safe_Aggregate (N);
end In_Place_Assign_OK;
------------------
-- Others_Check --
------------------
procedure Others_Check (Sub_Aggr : Node_Id; Dim : Pos) is
Aggr_Lo : constant Node_Id := Aggr_Low (Dim);
Aggr_Hi : constant Node_Id := Aggr_High (Dim);
-- The bounds of the aggregate for this dimension
Ind_Typ : constant Entity_Id := Aggr_Index_Typ (Dim);
-- The index type for this dimension
Need_To_Check : Boolean := False;
Choices_Lo : Node_Id := Empty;
Choices_Hi : Node_Id := Empty;
-- The lowest and highest discrete choices for a named sub-aggregate
Nb_Choices : Int := -1;
-- The number of discrete non-others choices in this sub-aggregate
Nb_Elements : Uint := Uint_0;
-- The number of elements in a positional aggregate
Cond : Node_Id := Empty;
Assoc : Node_Id;
Choice : Node_Id;
Expr : Node_Id;
begin
-- Check if we have an others choice. If we do make sure that this
-- sub-aggregate contains at least one element in addition to the
-- others choice.
if Range_Checks_Suppressed (Ind_Typ) then
Need_To_Check := False;
elsif Present (Expressions (Sub_Aggr))
and then Present (Component_Associations (Sub_Aggr))
then
Need_To_Check := True;
elsif Present (Component_Associations (Sub_Aggr)) then
Assoc := Last (Component_Associations (Sub_Aggr));
if Nkind (First (Choices (Assoc))) /= N_Others_Choice then
Need_To_Check := False;
else
-- Count the number of discrete choices. Start with -1 because
-- the others choice does not count.
Nb_Choices := -1;
Assoc := First (Component_Associations (Sub_Aggr));
while Present (Assoc) loop
Choice := First (Choices (Assoc));
while Present (Choice) loop
Nb_Choices := Nb_Choices + 1;
Next (Choice);
end loop;
Next (Assoc);
end loop;
-- If there is only an others choice nothing to do
Need_To_Check := (Nb_Choices > 0);
end if;
else
Need_To_Check := False;
end if;
-- If we are dealing with a positional sub-aggregate with an others
-- choice then compute the number or positional elements.
if Need_To_Check and then Present (Expressions (Sub_Aggr)) then
Expr := First (Expressions (Sub_Aggr));
Nb_Elements := Uint_0;
while Present (Expr) loop
Nb_Elements := Nb_Elements + 1;
Next (Expr);
end loop;
-- If the aggregate contains discrete choices and an others choice
-- compute the smallest and largest discrete choice values.
elsif Need_To_Check then
Compute_Choices_Lo_And_Choices_Hi : declare
Table : Case_Table_Type (1 .. Nb_Choices);
-- Used to sort all the different choice values
J : Pos := 1;
Low : Node_Id;
High : Node_Id;
begin
Assoc := First (Component_Associations (Sub_Aggr));
while Present (Assoc) loop
Choice := First (Choices (Assoc));
while Present (Choice) loop
if Nkind (Choice) = N_Others_Choice then
exit;
end if;
Get_Index_Bounds (Choice, Low, High);
Table (J).Choice_Lo := Low;
Table (J).Choice_Hi := High;
J := J + 1;
Next (Choice);
end loop;
Next (Assoc);
end loop;
-- Sort the discrete choices
Sort_Case_Table (Table);
Choices_Lo := Table (1).Choice_Lo;
Choices_Hi := Table (Nb_Choices).Choice_Hi;
end Compute_Choices_Lo_And_Choices_Hi;
end if;
-- If no others choice in this sub-aggregate, or the aggregate
-- comprises only an others choice, nothing to do.
if not Need_To_Check then
Cond := Empty;
-- If we are dealing with an aggregate containing an others choice
-- and positional components, we generate the following test:
-- if Ind_Typ'Pos (Aggr_Lo) + (Nb_Elements - 1) >
-- Ind_Typ'Pos (Aggr_Hi)
-- then
-- raise Constraint_Error;
-- end if;
elsif Nb_Elements > Uint_0 then
Cond :=
Make_Op_Gt (Loc,
Left_Opnd =>
Make_Op_Add (Loc,
Left_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => New_Reference_To (Ind_Typ, Loc),
Attribute_Name => Name_Pos,
Expressions =>
New_List
(Duplicate_Subexpr_Move_Checks (Aggr_Lo))),
Right_Opnd => Make_Integer_Literal (Loc, Nb_Elements - 1)),
Right_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => New_Reference_To (Ind_Typ, Loc),
Attribute_Name => Name_Pos,
Expressions => New_List (
Duplicate_Subexpr_Move_Checks (Aggr_Hi))));
-- If we are dealing with an aggregate containing an others choice
-- and discrete choices we generate the following test:
-- [constraint_error when
-- Choices_Lo < Aggr_Lo or else Choices_Hi > Aggr_Hi];
else
Cond :=
Make_Or_Else (Loc,
Left_Opnd =>
Make_Op_Lt (Loc,
Left_Opnd =>
Duplicate_Subexpr_Move_Checks (Choices_Lo),
Right_Opnd =>
Duplicate_Subexpr_Move_Checks (Aggr_Lo)),
Right_Opnd =>
Make_Op_Gt (Loc,
Left_Opnd =>
Duplicate_Subexpr (Choices_Hi),
Right_Opnd =>
Duplicate_Subexpr (Aggr_Hi)));
end if;
if Present (Cond) then
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
Reason => CE_Length_Check_Failed));
-- Questionable reason code, shouldn't that be a
-- CE_Range_Check_Failed ???
end if;
-- Now look inside the sub-aggregate to see if there is more work
if Dim < Aggr_Dimension then
-- Process positional components
if Present (Expressions (Sub_Aggr)) then
Expr := First (Expressions (Sub_Aggr));
while Present (Expr) loop
Others_Check (Expr, Dim + 1);
Next (Expr);
end loop;
end if;
-- Process component associations
if Present (Component_Associations (Sub_Aggr)) then
Assoc := First (Component_Associations (Sub_Aggr));
while Present (Assoc) loop
Expr := Expression (Assoc);
Others_Check (Expr, Dim + 1);
Next (Assoc);
end loop;
end if;
end if;
end Others_Check;
-------------------------
-- Safe_Left_Hand_Side --
-------------------------
function Safe_Left_Hand_Side (N : Node_Id) return Boolean is
function Is_Safe_Index (Indx : Node_Id) return Boolean;
-- If the left-hand side includes an indexed component, check that
-- the indexes are free of side-effect.
-------------------
-- Is_Safe_Index --
-------------------
function Is_Safe_Index (Indx : Node_Id) return Boolean is
begin
if Is_Entity_Name (Indx) then
return True;
elsif Nkind (Indx) = N_Integer_Literal then
return True;
elsif Nkind (Indx) = N_Function_Call
and then Is_Entity_Name (Name (Indx))
and then
Has_Pragma_Pure_Function (Entity (Name (Indx)))
then
return True;
elsif Nkind (Indx) = N_Type_Conversion
and then Is_Safe_Index (Expression (Indx))
then
return True;
else
return False;
end if;
end Is_Safe_Index;
-- Start of processing for Safe_Left_Hand_Side
begin
if Is_Entity_Name (N) then
return True;
elsif Nkind_In (N, N_Explicit_Dereference, N_Selected_Component)
and then Safe_Left_Hand_Side (Prefix (N))
then
return True;
elsif Nkind (N) = N_Indexed_Component
and then Safe_Left_Hand_Side (Prefix (N))
and then
Is_Safe_Index (First (Expressions (N)))
then
return True;
elsif Nkind (N) = N_Unchecked_Type_Conversion then
return Safe_Left_Hand_Side (Expression (N));
else
return False;
end if;
end Safe_Left_Hand_Side;
-- Local variables
Tmp : Entity_Id;
-- Holds the temporary aggregate value
Tmp_Decl : Node_Id;
-- Holds the declaration of Tmp
Aggr_Code : List_Id;
Parent_Node : Node_Id;
Parent_Kind : Node_Kind;
-- Start of processing for Expand_Array_Aggregate
begin
-- Do not touch the special aggregates of attributes used for Asm calls
if Is_RTE (Ctyp, RE_Asm_Input_Operand)
or else Is_RTE (Ctyp, RE_Asm_Output_Operand)
then
return;
-- Do not expand an aggregate for an array type which contains tasks if
-- the aggregate is associated with an unexpanded return statement of a
-- build-in-place function. The aggregate is expanded when the related
-- return statement (rewritten into an extended return) is processed.
-- This delay ensures that any temporaries and initialization code
-- generated for the aggregate appear in the proper return block and
-- use the correct _chain and _master.
elsif Has_Task (Base_Type (Etype (N)))
and then Nkind (Parent (N)) = N_Simple_Return_Statement
and then Is_Build_In_Place_Function
(Return_Applies_To (Return_Statement_Entity (Parent (N))))
then
return;
end if;
-- If the semantic analyzer has determined that aggregate N will raise
-- Constraint_Error at run time, then the aggregate node has been
-- replaced with an N_Raise_Constraint_Error node and we should
-- never get here.
pragma Assert (not Raises_Constraint_Error (N));
-- STEP 1a
-- Check that the index range defined by aggregate bounds is
-- compatible with corresponding index subtype.
Index_Compatibility_Check : declare
Aggr_Index_Range : Node_Id := First_Index (Typ);
-- The current aggregate index range
Index_Constraint : Node_Id := First_Index (Etype (Typ));
-- The corresponding index constraint against which we have to
-- check the above aggregate index range.
begin
Compute_Others_Present (N, 1);
for J in 1 .. Aggr_Dimension loop
-- There is no need to emit a check if an others choice is
-- present for this array aggregate dimension since in this
-- case one of N's sub-aggregates has taken its bounds from the
-- context and these bounds must have been checked already. In
-- addition all sub-aggregates corresponding to the same
-- dimension must all have the same bounds (checked in (c) below).
if not Range_Checks_Suppressed (Etype (Index_Constraint))
and then not Others_Present (J)
then
-- We don't use Checks.Apply_Range_Check here because it emits
-- a spurious check. Namely it checks that the range defined by
-- the aggregate bounds is non empty. But we know this already
-- if we get here.
Check_Bounds (Aggr_Index_Range, Index_Constraint);
end if;
-- Save the low and high bounds of the aggregate index as well as
-- the index type for later use in checks (b) and (c) below.
Aggr_Low (J) := Low_Bound (Aggr_Index_Range);
Aggr_High (J) := High_Bound (Aggr_Index_Range);
Aggr_Index_Typ (J) := Etype (Index_Constraint);
Next_Index (Aggr_Index_Range);
Next_Index (Index_Constraint);
end loop;
end Index_Compatibility_Check;
-- STEP 1b
-- If an others choice is present check that no aggregate index is
-- outside the bounds of the index constraint.
Others_Check (N, 1);
-- STEP 1c
-- For multidimensional arrays make sure that all subaggregates
-- corresponding to the same dimension have the same bounds.
if Aggr_Dimension > 1 then
Check_Same_Aggr_Bounds (N, 1);
end if;
-- STEP 2
-- Here we test for is packed array aggregate that we can handle at
-- compile time. If so, return with transformation done. Note that we do
-- this even if the aggregate is nested, because once we have done this
-- processing, there is no more nested aggregate!
if Packed_Array_Aggregate_Handled (N) then
return;
end if;
-- At this point we try to convert to positional form
if Ekind (Current_Scope) = E_Package
and then Static_Elaboration_Desired (Current_Scope)
then
Convert_To_Positional (N, Max_Others_Replicate => 100);
else
Convert_To_Positional (N);
end if;
-- if the result is no longer an aggregate (e.g. it may be a string
-- literal, or a temporary which has the needed value), then we are
-- done, since there is no longer a nested aggregate.
if Nkind (N) /= N_Aggregate then
return;
-- We are also done if the result is an analyzed aggregate, indicating
-- that Convert_To_Positional succeeded and reanalyzed the rewritten
-- aggregate.
elsif Analyzed (N)
and then N /= Original_Node (N)
then
return;
end if;
-- If all aggregate components are compile-time known and the aggregate
-- has been flattened, nothing left to do. The same occurs if the
-- aggregate is used to initialize the components of an statically
-- allocated dispatch table.
if Compile_Time_Known_Aggregate (N)
or else Is_Static_Dispatch_Table_Aggregate (N)
then
Set_Expansion_Delayed (N, False);
return;
end if;
-- Now see if back end processing is possible
if Backend_Processing_Possible (N) then
-- If the aggregate is static but the constraints are not, build
-- a static subtype for the aggregate, so that Gigi can place it
-- in static memory. Perform an unchecked_conversion to the non-
-- static type imposed by the context.
declare
Itype : constant Entity_Id := Etype (N);
Index : Node_Id;
Needs_Type : Boolean := False;
begin
Index := First_Index (Itype);
while Present (Index) loop
if not Is_Static_Subtype (Etype (Index)) then
Needs_Type := True;
exit;
else
Next_Index (Index);
end if;
end loop;
if Needs_Type then
Build_Constrained_Type (Positional => True);
Rewrite (N, Unchecked_Convert_To (Itype, N));
Analyze (N);
end if;
end;
return;
end if;
-- STEP 3
-- Delay expansion for nested aggregates: it will be taken care of
-- when the parent aggregate is expanded.
Parent_Node := Parent (N);
Parent_Kind := Nkind (Parent_Node);
if Parent_Kind = N_Qualified_Expression then
Parent_Node := Parent (Parent_Node);
Parent_Kind := Nkind (Parent_Node);
end if;
if Parent_Kind = N_Aggregate
or else Parent_Kind = N_Extension_Aggregate
or else Parent_Kind = N_Component_Association
or else (Parent_Kind = N_Object_Declaration
and then Needs_Finalization (Typ))
or else (Parent_Kind = N_Assignment_Statement
and then Inside_Init_Proc)
then
if Static_Array_Aggregate (N)
or else Compile_Time_Known_Aggregate (N)
then
Set_Expansion_Delayed (N, False);
return;
else
Set_Expansion_Delayed (N);
return;
end if;
end if;
-- STEP 4
-- Look if in place aggregate expansion is possible
-- For object declarations we build the aggregate in place, unless
-- the array is bit-packed or the component is controlled.
-- For assignments we do the assignment in place if all the component
-- associations have compile-time known values. For other cases we
-- create a temporary. The analysis for safety of on-line assignment
-- is delicate, i.e. we don't know how to do it fully yet ???
-- For allocators we assign to the designated object in place if the
-- aggregate meets the same conditions as other in-place assignments.
-- In this case the aggregate may not come from source but was created
-- for default initialization, e.g. with Initialize_Scalars.
if Requires_Transient_Scope (Typ) then
Establish_Transient_Scope
(N, Sec_Stack => Has_Controlled_Component (Typ));
end if;
if Has_Default_Init_Comps (N) then
Maybe_In_Place_OK := False;
elsif Is_Bit_Packed_Array (Typ)
or else Has_Controlled_Component (Typ)
then
Maybe_In_Place_OK := False;
else
Maybe_In_Place_OK :=
(Nkind (Parent (N)) = N_Assignment_Statement
and then Comes_From_Source (N)
and then In_Place_Assign_OK)
or else
(Nkind (Parent (Parent (N))) = N_Allocator
and then In_Place_Assign_OK);
end if;
-- If this is an array of tasks, it will be expanded into build-in-place
-- assignments. Build an activation chain for the tasks now.
if Has_Task (Etype (N)) then
Build_Activation_Chain_Entity (N);
end if;
-- Perform in-place expansion of aggregate in an object declaration.
-- Note: actions generated for the aggregate will be captured in an
-- expression-with-actions statement so that they can be transferred
-- to freeze actions later if there is an address clause for the
-- object. (Note: we don't use a block statement because this would
-- cause generated freeze nodes to be elaborated in the wrong scope).
-- Should document these individual tests ???
if not Has_Default_Init_Comps (N)
and then Comes_From_Source (Parent_Node)
and then Parent_Kind = N_Object_Declaration
and then not
Must_Slide (Etype (Defining_Identifier (Parent_Node)), Typ)
and then N = Expression (Parent_Node)
and then not Is_Bit_Packed_Array (Typ)
and then not Has_Controlled_Component (Typ)
then
Tmp := Defining_Identifier (Parent (N));
Set_No_Initialization (Parent (N));
Set_Expression (Parent (N), Empty);
-- Set the type of the entity, for use in the analysis of the
-- subsequent indexed assignments. If the nominal type is not
-- constrained, build a subtype from the known bounds of the
-- aggregate. If the declaration has a subtype mark, use it,
-- otherwise use the itype of the aggregate.
if not Is_Constrained (Typ) then
Build_Constrained_Type (Positional => False);
elsif Is_Entity_Name (Object_Definition (Parent (N)))
and then Is_Constrained (Entity (Object_Definition (Parent (N))))
then
Set_Etype (Tmp, Entity (Object_Definition (Parent (N))));
else
Set_Size_Known_At_Compile_Time (Typ, False);
Set_Etype (Tmp, Typ);
end if;
elsif Maybe_In_Place_OK
and then Nkind (Parent (N)) = N_Qualified_Expression
and then Nkind (Parent (Parent (N))) = N_Allocator
then
Set_Expansion_Delayed (N);
return;
-- In the remaining cases the aggregate is the RHS of an assignment
elsif Maybe_In_Place_OK
and then Safe_Left_Hand_Side (Name (Parent (N)))
then
Tmp := Name (Parent (N));
if Etype (Tmp) /= Etype (N) then
Apply_Length_Check (N, Etype (Tmp));
if Nkind (N) = N_Raise_Constraint_Error then
-- Static error, nothing further to expand
return;
end if;
end if;
elsif Maybe_In_Place_OK
and then Nkind (Name (Parent (N))) = N_Slice
and then Safe_Slice_Assignment (N)
then
-- Safe_Slice_Assignment rewrites assignment as a loop
return;
-- Step 5
-- In place aggregate expansion is not possible
else
Maybe_In_Place_OK := False;
Tmp := Make_Temporary (Loc, 'A', N);
Tmp_Decl :=
Make_Object_Declaration
(Loc,
Defining_Identifier => Tmp,
Object_Definition => New_Occurrence_Of (Typ, Loc));
Set_No_Initialization (Tmp_Decl, True);
-- If we are within a loop, the temporary will be pushed on the
-- stack at each iteration. If the aggregate is the expression for an
-- allocator, it will be immediately copied to the heap and can
-- be reclaimed at once. We create a transient scope around the
-- aggregate for this purpose.
if Ekind (Current_Scope) = E_Loop
and then Nkind (Parent (Parent (N))) = N_Allocator
then
Establish_Transient_Scope (N, False);
end if;
Insert_Action (N, Tmp_Decl);
end if;
-- Construct and insert the aggregate code. We can safely suppress index
-- checks because this code is guaranteed not to raise CE on index
-- checks. However we should *not* suppress all checks.
declare
Target : Node_Id;
begin
if Nkind (Tmp) = N_Defining_Identifier then
Target := New_Reference_To (Tmp, Loc);
else
if Has_Default_Init_Comps (N) then
-- Ada 2005 (AI-287): This case has not been analyzed???
raise Program_Error;
end if;
-- Name in assignment is explicit dereference
Target := New_Copy (Tmp);
end if;
Aggr_Code :=
Build_Array_Aggr_Code (N,
Ctype => Ctyp,
Index => First_Index (Typ),
Into => Target,
Scalar_Comp => Is_Scalar_Type (Ctyp));
end;
if Comes_From_Source (Tmp) then
declare
Node_After : constant Node_Id := Next (Parent_Node);
begin
Insert_Actions_After (Parent_Node, Aggr_Code);
if Parent_Kind = N_Object_Declaration then
Collect_Initialization_Statements
(Obj => Tmp, N => Parent_Node, Node_After => Node_After);
end if;
end;
else
Insert_Actions (N, Aggr_Code);
end if;
-- If the aggregate has been assigned in place, remove the original
-- assignment.
if Nkind (Parent (N)) = N_Assignment_Statement
and then Maybe_In_Place_OK
then
Rewrite (Parent (N), Make_Null_Statement (Loc));
elsif Nkind (Parent (N)) /= N_Object_Declaration
or else Tmp /= Defining_Identifier (Parent (N))
then
Rewrite (N, New_Occurrence_Of (Tmp, Loc));
Analyze_And_Resolve (N, Typ);
end if;
end Expand_Array_Aggregate;
------------------------
-- Expand_N_Aggregate --
------------------------
procedure Expand_N_Aggregate (N : Node_Id) is
begin
if Is_Record_Type (Etype (N)) then
Expand_Record_Aggregate (N);
else
Expand_Array_Aggregate (N);
end if;
exception
when RE_Not_Available =>
return;
end Expand_N_Aggregate;
----------------------------------
-- Expand_N_Extension_Aggregate --
----------------------------------
-- If the ancestor part is an expression, add a component association for
-- the parent field. If the type of the ancestor part is not the direct
-- parent of the expected type, build recursively the needed ancestors.
-- If the ancestor part is a subtype_mark, replace aggregate with a decla-
-- ration for a temporary of the expected type, followed by individual
-- assignments to the given components.
procedure Expand_N_Extension_Aggregate (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
A : constant Node_Id := Ancestor_Part (N);
Typ : constant Entity_Id := Etype (N);
begin
-- If the ancestor is a subtype mark, an init proc must be called
-- on the resulting object which thus has to be materialized in
-- the front-end
if Is_Entity_Name (A) and then Is_Type (Entity (A)) then
Convert_To_Assignments (N, Typ);
-- The extension aggregate is transformed into a record aggregate
-- of the following form (c1 and c2 are inherited components)
-- (Exp with c3 => a, c4 => b)
-- ==> (c1 => Exp.c1, c2 => Exp.c2, c3 => a, c4 => b)
else
Set_Etype (N, Typ);
if Tagged_Type_Expansion then
Expand_Record_Aggregate (N,
Orig_Tag =>
New_Occurrence_Of
(Node (First_Elmt (Access_Disp_Table (Typ))), Loc),
Parent_Expr => A);
-- No tag is needed in the case of a VM
else
Expand_Record_Aggregate (N, Parent_Expr => A);
end if;
end if;
exception
when RE_Not_Available =>
return;
end Expand_N_Extension_Aggregate;
-----------------------------
-- Expand_Record_Aggregate --
-----------------------------
procedure Expand_Record_Aggregate
(N : Node_Id;
Orig_Tag : Node_Id := Empty;
Parent_Expr : Node_Id := Empty)
is
Loc : constant Source_Ptr := Sloc (N);
Comps : constant List_Id := Component_Associations (N);
Typ : constant Entity_Id := Etype (N);
Base_Typ : constant Entity_Id := Base_Type (Typ);
Static_Components : Boolean := True;
-- Flag to indicate whether all components are compile-time known,
-- and the aggregate can be constructed statically and handled by
-- the back-end.
function Compile_Time_Known_Composite_Value (N : Node_Id) return Boolean;
-- Returns true if N is an expression of composite type which can be
-- fully evaluated at compile time without raising constraint error.
-- Such expressions can be passed as is to Gigi without any expansion.
--
-- This returns true for N_Aggregate with Compile_Time_Known_Aggregate
-- set and constants whose expression is such an aggregate, recursively.
function Component_Not_OK_For_Backend return Boolean;
-- Check for presence of component which makes it impossible for the
-- backend to process the aggregate, thus requiring the use of a series
-- of assignment statements. Cases checked for are a nested aggregate
-- needing Late_Expansion, the presence of a tagged component which may
-- need tag adjustment, and a bit unaligned component reference.
--
-- We also force expansion into assignments if a component is of a
-- mutable type (including a private type with discriminants) because
-- in that case the size of the component to be copied may be smaller
-- than the side of the target, and there is no simple way for gigi
-- to compute the size of the object to be copied.
--
-- NOTE: This is part of the ongoing work to define precisely the
-- interface between front-end and back-end handling of aggregates.
-- In general it is desirable to pass aggregates as they are to gigi,
-- in order to minimize elaboration code. This is one case where the
-- semantics of Ada complicate the analysis and lead to anomalies in
-- the gcc back-end if the aggregate is not expanded into assignments.
function Has_Visible_Private_Ancestor (Id : E) return Boolean;
-- If any ancestor of the current type is private, the aggregate
-- cannot be built in place. We canot rely on Has_Private_Ancestor,
-- because it will not be set when type and its parent are in the
-- same scope, and the parent component needs expansion.
function Top_Level_Aggregate (N : Node_Id) return Node_Id;
-- For nested aggregates return the ultimate enclosing aggregate; for
-- non-nested aggregates return N.
----------------------------------------
-- Compile_Time_Known_Composite_Value --
----------------------------------------
function Compile_Time_Known_Composite_Value
(N : Node_Id) return Boolean
is
begin
-- If we have an entity name, then see if it is the name of a
-- constant and if so, test the corresponding constant value.
if Is_Entity_Name (N) then
declare
E : constant Entity_Id := Entity (N);
V : Node_Id;
begin
if Ekind (E) /= E_Constant then
return False;
else
V := Constant_Value (E);
return Present (V)
and then Compile_Time_Known_Composite_Value (V);
end if;
end;
-- We have a value, see if it is compile time known
else
if Nkind (N) = N_Aggregate then
return Compile_Time_Known_Aggregate (N);
end if;
-- All other types of values are not known at compile time
return False;
end if;
end Compile_Time_Known_Composite_Value;
----------------------------------
-- Component_Not_OK_For_Backend --
----------------------------------
function Component_Not_OK_For_Backend return Boolean is
C : Node_Id;
Expr_Q : Node_Id;
begin
if No (Comps) then
return False;
end if;
C := First (Comps);
while Present (C) loop
-- If the component has box initialization, expansion is needed
-- and component is not ready for backend.
if Box_Present (C) then
return True;
end if;
if Nkind (Expression (C)) = N_Qualified_Expression then
Expr_Q := Expression (Expression (C));
else
Expr_Q := Expression (C);
end if;
-- Return true if the aggregate has any associations for tagged
-- components that may require tag adjustment.
-- These are cases where the source expression may have a tag that
-- could differ from the component tag (e.g., can occur for type
-- conversions and formal parameters). (Tag adjustment not needed
-- if VM_Target because object tags are implicit in the machine.)
if Is_Tagged_Type (Etype (Expr_Q))
and then (Nkind (Expr_Q) = N_Type_Conversion
or else (Is_Entity_Name (Expr_Q)
and then
Ekind (Entity (Expr_Q)) in Formal_Kind))
and then Tagged_Type_Expansion
then
Static_Components := False;
return True;
elsif Is_Delayed_Aggregate (Expr_Q) then
Static_Components := False;
return True;
elsif Possible_Bit_Aligned_Component (Expr_Q) then
Static_Components := False;
return True;
end if;
if Is_Elementary_Type (Etype (Expr_Q)) then
if not Compile_Time_Known_Value (Expr_Q) then
Static_Components := False;
end if;
elsif not Compile_Time_Known_Composite_Value (Expr_Q) then
Static_Components := False;
if Is_Private_Type (Etype (Expr_Q))
and then Has_Discriminants (Etype (Expr_Q))
then
return True;
end if;
end if;
Next (C);
end loop;
return False;
end Component_Not_OK_For_Backend;
-----------------------------------
-- Has_Visible_Private_Ancestor --
-----------------------------------
function Has_Visible_Private_Ancestor (Id : E) return Boolean is
R : constant Entity_Id := Root_Type (Id);
T1 : Entity_Id := Id;
begin
loop
if Is_Private_Type (T1) then
return True;
elsif T1 = R then
return False;
else
T1 := Etype (T1);
end if;
end loop;
end Has_Visible_Private_Ancestor;
-------------------------
-- Top_Level_Aggregate --
-------------------------
function Top_Level_Aggregate (N : Node_Id) return Node_Id is
Aggr : Node_Id;
begin
Aggr := N;
while Present (Parent (Aggr))
and then Nkind_In (Parent (Aggr), N_Component_Association,
N_Aggregate)
loop
Aggr := Parent (Aggr);
end loop;
return Aggr;
end Top_Level_Aggregate;
-- Local variables
Top_Level_Aggr : constant Node_Id := Top_Level_Aggregate (N);
Tag_Value : Node_Id;
Comp : Entity_Id;
New_Comp : Node_Id;
-- Start of processing for Expand_Record_Aggregate
begin
-- If the aggregate is to be assigned to an atomic variable, we
-- have to prevent a piecemeal assignment even if the aggregate
-- is to be expanded. We create a temporary for the aggregate, and
-- assign the temporary instead, so that the back end can generate
-- an atomic move for it.
if Is_Atomic (Typ)
and then Comes_From_Source (Parent (N))
and then Is_Atomic_Aggregate (N, Typ)
then
return;
-- No special management required for aggregates used to initialize
-- statically allocated dispatch tables
elsif Is_Static_Dispatch_Table_Aggregate (N) then
return;
end if;
-- Ada 2005 (AI-318-2): We need to convert to assignments if components
-- are build-in-place function calls. The assignments will each turn
-- into a build-in-place function call. If components are all static,
-- we can pass the aggregate to the backend regardless of limitedness.
-- Extension aggregates, aggregates in extended return statements, and
-- aggregates for C++ imported types must be expanded.
if Ada_Version >= Ada_2005 and then Is_Immutably_Limited_Type (Typ) then
if not Nkind_In (Parent (N), N_Object_Declaration,
N_Component_Association)
then
Convert_To_Assignments (N, Typ);
elsif Nkind (N) = N_Extension_Aggregate
or else Convention (Typ) = Convention_CPP
then
Convert_To_Assignments (N, Typ);
elsif not Size_Known_At_Compile_Time (Typ)
or else Component_Not_OK_For_Backend
or else not Static_Components
then
Convert_To_Assignments (N, Typ);
else
Set_Compile_Time_Known_Aggregate (N);
Set_Expansion_Delayed (N, False);
end if;
-- Gigi doesn't properly handle temporaries of variable size so we
-- generate it in the front-end
elsif not Size_Known_At_Compile_Time (Typ)
and then Tagged_Type_Expansion
then
Convert_To_Assignments (N, Typ);
-- Temporaries for controlled aggregates need to be attached to a final
-- chain in order to be properly finalized, so it has to be created in
-- the front-end
elsif Is_Controlled (Typ)
or else Has_Controlled_Component (Base_Type (Typ))
then
Convert_To_Assignments (N, Typ);
-- Ada 2005 (AI-287): In case of default initialized components we
-- convert the aggregate into assignments.
elsif Has_Default_Init_Comps (N) then
Convert_To_Assignments (N, Typ);
-- Check components
elsif Component_Not_OK_For_Backend then
Convert_To_Assignments (N, Typ);
-- If an ancestor is private, some components are not inherited and we
-- cannot expand into a record aggregate.
elsif Has_Visible_Private_Ancestor (Typ) then
Convert_To_Assignments (N, Typ);
-- ??? The following was done to compile fxacc00.ads in the ACVCs. Gigi
-- is not able to handle the aggregate for Late_Request.
elsif Is_Tagged_Type (Typ) and then Has_Discriminants (Typ) then
Convert_To_Assignments (N, Typ);
-- If the tagged types covers interface types we need to initialize all
-- hidden components containing pointers to secondary dispatch tables.
elsif Is_Tagged_Type (Typ) and then Has_Interfaces (Typ) then
Convert_To_Assignments (N, Typ);
-- If some components are mutable, the size of the aggregate component
-- may be distinct from the default size of the type component, so
-- we need to expand to insure that the back-end copies the proper
-- size of the data. However, if the aggregate is the initial value of
-- a constant, the target is immutable and might be built statically
-- if components are appropriate.
elsif Has_Mutable_Components (Typ)
and then
(Nkind (Parent (Top_Level_Aggr)) /= N_Object_Declaration
or else not Constant_Present (Parent (Top_Level_Aggr))
or else not Static_Components)
then
Convert_To_Assignments (N, Typ);
-- If the type involved has any non-bit aligned components, then we are
-- not sure that the back end can handle this case correctly.
elsif Type_May_Have_Bit_Aligned_Components (Typ) then
Convert_To_Assignments (N, Typ);
-- In all other cases, build a proper aggregate handlable by gigi
else
if Nkind (N) = N_Aggregate then
-- If the aggregate is static and can be handled by the back-end,
-- nothing left to do.
if Static_Components then
Set_Compile_Time_Known_Aggregate (N);
Set_Expansion_Delayed (N, False);
end if;
end if;
-- If no discriminants, nothing special to do
if not Has_Discriminants (Typ) then
null;
-- Case of discriminants present
elsif Is_Derived_Type (Typ) then
-- For untagged types, non-stored discriminants are replaced
-- with stored discriminants, which are the ones that gigi uses
-- to describe the type and its components.
Generate_Aggregate_For_Derived_Type : declare
Constraints : constant List_Id := New_List;
First_Comp : Node_Id;
Discriminant : Entity_Id;
Decl : Node_Id;
Num_Disc : Int := 0;
Num_Gird : Int := 0;
procedure Prepend_Stored_Values (T : Entity_Id);
-- Scan the list of stored discriminants of the type, and add
-- their values to the aggregate being built.
---------------------------
-- Prepend_Stored_Values --
---------------------------
procedure Prepend_Stored_Values (T : Entity_Id) is
begin
Discriminant := First_Stored_Discriminant (T);
while Present (Discriminant) loop
New_Comp :=
Make_Component_Association (Loc,
Choices =>
New_List (New_Occurrence_Of (Discriminant, Loc)),
Expression =>
New_Copy_Tree (
Get_Discriminant_Value (
Discriminant,
Typ,
Discriminant_Constraint (Typ))));
if No (First_Comp) then
Prepend_To (Component_Associations (N), New_Comp);
else
Insert_After (First_Comp, New_Comp);
end if;
First_Comp := New_Comp;
Next_Stored_Discriminant (Discriminant);
end loop;
end Prepend_Stored_Values;
-- Start of processing for Generate_Aggregate_For_Derived_Type
begin
-- Remove the associations for the discriminant of derived type
First_Comp := First (Component_Associations (N));
while Present (First_Comp) loop
Comp := First_Comp;
Next (First_Comp);
if Ekind (Entity
(First (Choices (Comp)))) = E_Discriminant
then
Remove (Comp);
Num_Disc := Num_Disc + 1;
end if;
end loop;
-- Insert stored discriminant associations in the correct
-- order. If there are more stored discriminants than new
-- discriminants, there is at least one new discriminant that
-- constrains more than one of the stored discriminants. In
-- this case we need to construct a proper subtype of the
-- parent type, in order to supply values to all the
-- components. Otherwise there is one-one correspondence
-- between the constraints and the stored discriminants.
First_Comp := Empty;
Discriminant := First_Stored_Discriminant (Base_Type (Typ));
while Present (Discriminant) loop
Num_Gird := Num_Gird + 1;
Next_Stored_Discriminant (Discriminant);
end loop;
-- Case of more stored discriminants than new discriminants
if Num_Gird > Num_Disc then
-- Create a proper subtype of the parent type, which is the
-- proper implementation type for the aggregate, and convert
-- it to the intended target type.
Discriminant := First_Stored_Discriminant (Base_Type (Typ));
while Present (Discriminant) loop
New_Comp :=
New_Copy_Tree (
Get_Discriminant_Value (
Discriminant,
Typ,
Discriminant_Constraint (Typ)));
Append (New_Comp, Constraints);
Next_Stored_Discriminant (Discriminant);
end loop;
Decl :=
Make_Subtype_Declaration (Loc,
Defining_Identifier => Make_Temporary (Loc, 'T'),
Subtype_Indication =>
Make_Subtype_Indication (Loc,
Subtype_Mark =>
New_Occurrence_Of (Etype (Base_Type (Typ)), Loc),
Constraint =>
Make_Index_Or_Discriminant_Constraint
(Loc, Constraints)));
Insert_Action (N, Decl);
Prepend_Stored_Values (Base_Type (Typ));
Set_Etype (N, Defining_Identifier (Decl));
Set_Analyzed (N);
Rewrite (N, Unchecked_Convert_To (Typ, N));
Analyze (N);
-- Case where we do not have fewer new discriminants than
-- stored discriminants, so in this case we can simply use the
-- stored discriminants of the subtype.
else
Prepend_Stored_Values (Typ);
end if;
end Generate_Aggregate_For_Derived_Type;
end if;
if Is_Tagged_Type (Typ) then
-- In the tagged case, _parent and _tag component must be created
-- Reset Null_Present unconditionally. Tagged records always have
-- at least one field (the tag or the parent).
Set_Null_Record_Present (N, False);
-- When the current aggregate comes from the expansion of an
-- extension aggregate, the parent expr is replaced by an
-- aggregate formed by selected components of this expr.
if Present (Parent_Expr)
and then Is_Empty_List (Comps)
then
Comp := First_Component_Or_Discriminant (Typ);
while Present (Comp) loop
-- Skip all expander-generated components
if
not Comes_From_Source (Original_Record_Component (Comp))
then
null;
else
New_Comp :=
Make_Selected_Component (Loc,
Prefix =>
Unchecked_Convert_To (Typ,
Duplicate_Subexpr (Parent_Expr, True)),
Selector_Name => New_Occurrence_Of (Comp, Loc));
Append_To (Comps,
Make_Component_Association (Loc,
Choices =>
New_List (New_Occurrence_Of (Comp, Loc)),
Expression =>
New_Comp));
Analyze_And_Resolve (New_Comp, Etype (Comp));
end if;
Next_Component_Or_Discriminant (Comp);
end loop;
end if;
-- Compute the value for the Tag now, if the type is a root it
-- will be included in the aggregate right away, otherwise it will
-- be propagated to the parent aggregate.
if Present (Orig_Tag) then
Tag_Value := Orig_Tag;
elsif not Tagged_Type_Expansion then
Tag_Value := Empty;
else
Tag_Value :=
New_Occurrence_Of
(Node (First_Elmt (Access_Disp_Table (Typ))), Loc);
end if;
-- For a derived type, an aggregate for the parent is formed with
-- all the inherited components.
if Is_Derived_Type (Typ) then
declare
First_Comp : Node_Id;
Parent_Comps : List_Id;
Parent_Aggr : Node_Id;
Parent_Name : Node_Id;
begin
-- Remove the inherited component association from the
-- aggregate and store them in the parent aggregate
First_Comp := First (Component_Associations (N));
Parent_Comps := New_List;
while Present (First_Comp)
and then Scope (Original_Record_Component (
Entity (First (Choices (First_Comp))))) /= Base_Typ
loop
Comp := First_Comp;
Next (First_Comp);
Remove (Comp);
Append (Comp, Parent_Comps);
end loop;
Parent_Aggr := Make_Aggregate (Loc,
Component_Associations => Parent_Comps);
Set_Etype (Parent_Aggr, Etype (Base_Type (Typ)));
-- Find the _parent component
Comp := First_Component (Typ);
while Chars (Comp) /= Name_uParent loop
Comp := Next_Component (Comp);
end loop;
Parent_Name := New_Occurrence_Of (Comp, Loc);
-- Insert the parent aggregate
Prepend_To (Component_Associations (N),
Make_Component_Association (Loc,
Choices => New_List (Parent_Name),
Expression => Parent_Aggr));
-- Expand recursively the parent propagating the right Tag
Expand_Record_Aggregate
(Parent_Aggr, Tag_Value, Parent_Expr);
-- The ancestor part may be a nested aggregate that has
-- delayed expansion: recheck now.
if Component_Not_OK_For_Backend then
Convert_To_Assignments (N, Typ);
end if;
end;
-- For a root type, the tag component is added (unless compiling
-- for the VMs, where tags are implicit).
elsif Tagged_Type_Expansion then
declare
Tag_Name : constant Node_Id :=
New_Occurrence_Of (First_Tag_Component (Typ), Loc);
Typ_Tag : constant Entity_Id := RTE (RE_Tag);
Conv_Node : constant Node_Id :=
Unchecked_Convert_To (Typ_Tag, Tag_Value);
begin
Set_Etype (Conv_Node, Typ_Tag);
Prepend_To (Component_Associations (N),
Make_Component_Association (Loc,
Choices => New_List (Tag_Name),
Expression => Conv_Node));
end;
end if;
end if;
end if;
end Expand_Record_Aggregate;
----------------------------
-- Has_Default_Init_Comps --
----------------------------
function Has_Default_Init_Comps (N : Node_Id) return Boolean is
Comps : constant List_Id := Component_Associations (N);
C : Node_Id;
Expr : Node_Id;
begin
pragma Assert (Nkind_In (N, N_Aggregate, N_Extension_Aggregate));
if No (Comps) then
return False;
end if;
if Has_Self_Reference (N) then
return True;
end if;
-- Check if any direct component has default initialized components
C := First (Comps);
while Present (C) loop
if Box_Present (C) then
return True;
end if;
Next (C);
end loop;
-- Recursive call in case of aggregate expression
C := First (Comps);
while Present (C) loop
Expr := Expression (C);
if Present (Expr)
and then
Nkind_In (Expr, N_Aggregate, N_Extension_Aggregate)
and then Has_Default_Init_Comps (Expr)
then
return True;
end if;
Next (C);
end loop;
return False;
end Has_Default_Init_Comps;
--------------------------
-- Is_Delayed_Aggregate --
--------------------------
function Is_Delayed_Aggregate (N : Node_Id) return Boolean is
Node : Node_Id := N;
Kind : Node_Kind := Nkind (Node);
begin
if Kind = N_Qualified_Expression then
Node := Expression (Node);
Kind := Nkind (Node);
end if;
if Kind /= N_Aggregate and then Kind /= N_Extension_Aggregate then
return False;
else
return Expansion_Delayed (Node);
end if;
end Is_Delayed_Aggregate;
----------------------------------------
-- Is_Static_Dispatch_Table_Aggregate --
----------------------------------------
function Is_Static_Dispatch_Table_Aggregate (N : Node_Id) return Boolean is
Typ : constant Entity_Id := Base_Type (Etype (N));
begin
return Static_Dispatch_Tables
and then Tagged_Type_Expansion
and then RTU_Loaded (Ada_Tags)
-- Avoid circularity when rebuilding the compiler
and then Cunit_Entity (Get_Source_Unit (N)) /= RTU_Entity (Ada_Tags)
and then (Typ = RTE (RE_Dispatch_Table_Wrapper)
or else
Typ = RTE (RE_Address_Array)
or else
Typ = RTE (RE_Type_Specific_Data)
or else
Typ = RTE (RE_Tag_Table)
or else
(RTE_Available (RE_Interface_Data)
and then Typ = RTE (RE_Interface_Data))
or else
(RTE_Available (RE_Interfaces_Array)
and then Typ = RTE (RE_Interfaces_Array))
or else
(RTE_Available (RE_Interface_Data_Element)
and then Typ = RTE (RE_Interface_Data_Element)));
end Is_Static_Dispatch_Table_Aggregate;
-----------------------------
-- Is_Two_Dim_Packed_Array --
-----------------------------
function Is_Two_Dim_Packed_Array (Typ : Entity_Id) return Boolean is
C : constant Int := UI_To_Int (Component_Size (Typ));
begin
return Number_Dimensions (Typ) = 2
and then Is_Bit_Packed_Array (Typ)
and then (C = 1 or else C = 2 or else C = 4);
end Is_Two_Dim_Packed_Array;
--------------------
-- Late_Expansion --
--------------------
function Late_Expansion
(N : Node_Id;
Typ : Entity_Id;
Target : Node_Id) return List_Id
is
begin
if Is_Record_Type (Etype (N)) then
return Build_Record_Aggr_Code (N, Typ, Target);
else pragma Assert (Is_Array_Type (Etype (N)));
return
Build_Array_Aggr_Code
(N => N,
Ctype => Component_Type (Etype (N)),
Index => First_Index (Typ),
Into => Target,
Scalar_Comp => Is_Scalar_Type (Component_Type (Typ)),
Indexes => No_List);
end if;
end Late_Expansion;
----------------------------------
-- Make_OK_Assignment_Statement --
----------------------------------
function Make_OK_Assignment_Statement
(Sloc : Source_Ptr;
Name : Node_Id;
Expression : Node_Id) return Node_Id
is
begin
Set_Assignment_OK (Name);
return Make_Assignment_Statement (Sloc, Name, Expression);
end Make_OK_Assignment_Statement;
-----------------------
-- Number_Of_Choices --
-----------------------
function Number_Of_Choices (N : Node_Id) return Nat is
Assoc : Node_Id;
Choice : Node_Id;
Nb_Choices : Nat := 0;
begin
if Present (Expressions (N)) then
return 0;
end if;
Assoc := First (Component_Associations (N));
while Present (Assoc) loop
Choice := First (Choices (Assoc));
while Present (Choice) loop
if Nkind (Choice) /= N_Others_Choice then
Nb_Choices := Nb_Choices + 1;
end if;
Next (Choice);
end loop;
Next (Assoc);
end loop;
return Nb_Choices;
end Number_Of_Choices;
------------------------------------
-- Packed_Array_Aggregate_Handled --
------------------------------------
-- The current version of this procedure will handle at compile time
-- any array aggregate that meets these conditions:
-- One and two dimensional, bit packed
-- Underlying packed type is modular type
-- Bounds are within 32-bit Int range
-- All bounds and values are static
-- Note: for now, in the 2-D case, we only handle component sizes of
-- 1, 2, 4 (cases where an integral number of elements occupies a byte).
function Packed_Array_Aggregate_Handled (N : Node_Id) return Boolean is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
Ctyp : constant Entity_Id := Component_Type (Typ);
Not_Handled : exception;
-- Exception raised if this aggregate cannot be handled
begin
-- Handle one- or two dimensional bit packed array
if not Is_Bit_Packed_Array (Typ)
or else Number_Dimensions (Typ) > 2
then
return False;
end if;
-- If two-dimensional, check whether it can be folded, and transformed
-- into a one-dimensional aggregate for the Packed_Array_Type of the
-- original type.
if Number_Dimensions (Typ) = 2 then
return Two_Dim_Packed_Array_Handled (N);
end if;
if not Is_Modular_Integer_Type (Packed_Array_Type (Typ)) then
return False;
end if;
if not Is_Scalar_Type (Component_Type (Typ))
and then Has_Non_Standard_Rep (Component_Type (Typ))
then
return False;
end if;
declare
Csiz : constant Nat := UI_To_Int (Component_Size (Typ));
Lo : Node_Id;
Hi : Node_Id;
-- Bounds of index type
Lob : Uint;
Hib : Uint;
-- Values of bounds if compile time known
function Get_Component_Val (N : Node_Id) return Uint;
-- Given a expression value N of the component type Ctyp, returns a
-- value of Csiz (component size) bits representing this value. If
-- the value is non-static or any other reason exists why the value
-- cannot be returned, then Not_Handled is raised.
-----------------------
-- Get_Component_Val --
-----------------------
function Get_Component_Val (N : Node_Id) return Uint is
Val : Uint;
begin
-- We have to analyze the expression here before doing any further
-- processing here. The analysis of such expressions is deferred
-- till expansion to prevent some problems of premature analysis.
Analyze_And_Resolve (N, Ctyp);
-- Must have a compile time value. String literals have to be
-- converted into temporaries as well, because they cannot easily
-- be converted into their bit representation.
if not Compile_Time_Known_Value (N)
or else Nkind (N) = N_String_Literal
then
raise Not_Handled;
end if;
Val := Expr_Rep_Value (N);
-- Adjust for bias, and strip proper number of bits
if Has_Biased_Representation (Ctyp) then
Val := Val - Expr_Value (Type_Low_Bound (Ctyp));
end if;
return Val mod Uint_2 ** Csiz;
end Get_Component_Val;
-- Here we know we have a one dimensional bit packed array
begin
Get_Index_Bounds (First_Index (Typ), Lo, Hi);
-- Cannot do anything if bounds are dynamic
if not Compile_Time_Known_Value (Lo)
or else
not Compile_Time_Known_Value (Hi)
then
return False;
end if;
-- Or are silly out of range of int bounds
Lob := Expr_Value (Lo);
Hib := Expr_Value (Hi);
if not UI_Is_In_Int_Range (Lob)
or else
not UI_Is_In_Int_Range (Hib)
then
return False;
end if;
-- At this stage we have a suitable aggregate for handling at compile
-- time. The only remaining checks are that the values of expressions
-- in the aggregate are compile-time known (checks are performed by
-- Get_Component_Val, and that any subtypes or ranges are statically
-- known.
-- If the aggregate is not fully positional at this stage, then
-- convert it to positional form. Either this will fail, in which
-- case we can do nothing, or it will succeed, in which case we have
-- succeeded in handling the aggregate and transforming it into a
-- modular value, or it will stay an aggregate, in which case we
-- have failed to create a packed value for it.
if Present (Component_Associations (N)) then
Convert_To_Positional
(N, Max_Others_Replicate => 64, Handle_Bit_Packed => True);
return Nkind (N) /= N_Aggregate;
end if;
-- Otherwise we are all positional, so convert to proper value
declare
Lov : constant Int := UI_To_Int (Lob);
Hiv : constant Int := UI_To_Int (Hib);
Len : constant Nat := Int'Max (0, Hiv - Lov + 1);
-- The length of the array (number of elements)
Aggregate_Val : Uint;
-- Value of aggregate. The value is set in the low order bits of
-- this value. For the little-endian case, the values are stored
-- from low-order to high-order and for the big-endian case the
-- values are stored from high-order to low-order. Note that gigi
-- will take care of the conversions to left justify the value in
-- the big endian case (because of left justified modular type
-- processing), so we do not have to worry about that here.
Lit : Node_Id;
-- Integer literal for resulting constructed value
Shift : Nat;
-- Shift count from low order for next value
Incr : Int;
-- Shift increment for loop
Expr : Node_Id;
-- Next expression from positional parameters of aggregate
Left_Justified : Boolean;
-- Set True if we are filling the high order bits of the target
-- value (i.e. the value is left justified).
begin
-- For little endian, we fill up the low order bits of the target
-- value. For big endian we fill up the high order bits of the
-- target value (which is a left justified modular value).
Left_Justified := Bytes_Big_Endian;
-- Switch justification if using -gnatd8
if Debug_Flag_8 then
Left_Justified := not Left_Justified;
end if;
-- Switch justfification if reverse storage order
if Reverse_Storage_Order (Base_Type (Typ)) then
Left_Justified := not Left_Justified;
end if;
if Left_Justified then
Shift := Csiz * (Len - 1);
Incr := -Csiz;
else
Shift := 0;
Incr := +Csiz;
end if;
-- Loop to set the values
if Len = 0 then
Aggregate_Val := Uint_0;
else
Expr := First (Expressions (N));
Aggregate_Val := Get_Component_Val (Expr) * Uint_2 ** Shift;
for J in 2 .. Len loop
Shift := Shift + Incr;
Next (Expr);
Aggregate_Val :=
Aggregate_Val + Get_Component_Val (Expr) * Uint_2 ** Shift;
end loop;
end if;
-- Now we can rewrite with the proper value
Lit := Make_Integer_Literal (Loc, Intval => Aggregate_Val);
Set_Print_In_Hex (Lit);
-- Construct the expression using this literal. Note that it is
-- important to qualify the literal with its proper modular type
-- since universal integer does not have the required range and
-- also this is a left justified modular type, which is important
-- in the big-endian case.
Rewrite (N,
Unchecked_Convert_To (Typ,
Make_Qualified_Expression (Loc,
Subtype_Mark =>
New_Occurrence_Of (Packed_Array_Type (Typ), Loc),
Expression => Lit)));
Analyze_And_Resolve (N, Typ);
return True;
end;
end;
exception
when Not_Handled =>
return False;
end Packed_Array_Aggregate_Handled;
----------------------------
-- Has_Mutable_Components --
----------------------------
function Has_Mutable_Components (Typ : Entity_Id) return Boolean is
Comp : Entity_Id;
begin
Comp := First_Component (Typ);
while Present (Comp) loop
if Is_Record_Type (Etype (Comp))
and then Has_Discriminants (Etype (Comp))
and then not Is_Constrained (Etype (Comp))
then
return True;
end if;
Next_Component (Comp);
end loop;
return False;
end Has_Mutable_Components;
------------------------------
-- Initialize_Discriminants --
------------------------------
procedure Initialize_Discriminants (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
Bas : constant Entity_Id := Base_Type (Typ);
Par : constant Entity_Id := Etype (Bas);
Decl : constant Node_Id := Parent (Par);
Ref : Node_Id;
begin
if Is_Tagged_Type (Bas)
and then Is_Derived_Type (Bas)
and then Has_Discriminants (Par)
and then Has_Discriminants (Bas)
and then Number_Discriminants (Bas) /= Number_Discriminants (Par)
and then Nkind (Decl) = N_Full_Type_Declaration
and then Nkind (Type_Definition (Decl)) = N_Record_Definition
and then Present
(Variant_Part (Component_List (Type_Definition (Decl))))
and then Nkind (N) /= N_Extension_Aggregate
then
-- Call init proc to set discriminants.
-- There should eventually be a special procedure for this ???
Ref := New_Reference_To (Defining_Identifier (N), Loc);
Insert_Actions_After (N,
Build_Initialization_Call (Sloc (N), Ref, Typ));
end if;
end Initialize_Discriminants;
----------------
-- Must_Slide --
----------------
function Must_Slide
(Obj_Type : Entity_Id;
Typ : Entity_Id) return Boolean
is
L1, L2, H1, H2 : Node_Id;
begin
-- No sliding if the type of the object is not established yet, if it is
-- an unconstrained type whose actual subtype comes from the aggregate,
-- or if the two types are identical.
if not Is_Array_Type (Obj_Type) then
return False;
elsif not Is_Constrained (Obj_Type) then
return False;
elsif Typ = Obj_Type then
return False;
else
-- Sliding can only occur along the first dimension
Get_Index_Bounds (First_Index (Typ), L1, H1);
Get_Index_Bounds (First_Index (Obj_Type), L2, H2);
if not Is_Static_Expression (L1)
or else not Is_Static_Expression (L2)
or else not Is_Static_Expression (H1)
or else not Is_Static_Expression (H2)
then
return False;
else
return Expr_Value (L1) /= Expr_Value (L2)
or else
Expr_Value (H1) /= Expr_Value (H2);
end if;
end if;
end Must_Slide;
---------------------------
-- Safe_Slice_Assignment --
---------------------------
function Safe_Slice_Assignment (N : Node_Id) return Boolean is
Loc : constant Source_Ptr := Sloc (Parent (N));
Pref : constant Node_Id := Prefix (Name (Parent (N)));
Range_Node : constant Node_Id := Discrete_Range (Name (Parent (N)));
Expr : Node_Id;
L_J : Entity_Id;
L_Iter : Node_Id;
L_Body : Node_Id;
Stat : Node_Id;
begin
-- Generate: for J in Range loop Pref (J) := Expr; end loop;
if Comes_From_Source (N)
and then No (Expressions (N))
and then Nkind (First (Choices (First (Component_Associations (N)))))
= N_Others_Choice
then
Expr := Expression (First (Component_Associations (N)));
L_J := Make_Temporary (Loc, 'J');
L_Iter :=
Make_Iteration_Scheme (Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification
(Loc,
Defining_Identifier => L_J,
Discrete_Subtype_Definition => Relocate_Node (Range_Node)));
L_Body :=
Make_Assignment_Statement (Loc,
Name =>
Make_Indexed_Component (Loc,
Prefix => Relocate_Node (Pref),
Expressions => New_List (New_Occurrence_Of (L_J, Loc))),
Expression => Relocate_Node (Expr));
-- Construct the final loop
Stat :=
Make_Implicit_Loop_Statement
(Node => Parent (N),
Identifier => Empty,
Iteration_Scheme => L_Iter,
Statements => New_List (L_Body));
-- Set type of aggregate to be type of lhs in assignment,
-- to suppress redundant length checks.
Set_Etype (N, Etype (Name (Parent (N))));
Rewrite (Parent (N), Stat);
Analyze (Parent (N));
return True;
else
return False;
end if;
end Safe_Slice_Assignment;
----------------------------------
-- Two_Dim_Packed_Array_Handled --
----------------------------------
function Two_Dim_Packed_Array_Handled (N : Node_Id) return Boolean is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
Ctyp : constant Entity_Id := Component_Type (Typ);
Comp_Size : constant Int := UI_To_Int (Component_Size (Typ));
Packed_Array : constant Entity_Id := Packed_Array_Type (Base_Type (Typ));
One_Comp : Node_Id;
-- Expression in original aggregate
One_Dim : Node_Id;
-- One-dimensional subaggregate
begin
-- For now, only deal with cases where an integral number of elements
-- fit in a single byte. This includes the most common boolean case.
if not (Comp_Size = 1 or else
Comp_Size = 2 or else
Comp_Size = 4)
then
return False;
end if;
Convert_To_Positional
(N, Max_Others_Replicate => 64, Handle_Bit_Packed => True);
-- Verify that all components are static
if Nkind (N) = N_Aggregate
and then Compile_Time_Known_Aggregate (N)
then
null;
-- The aggregate may have been re-analyzed and converted already
elsif Nkind (N) /= N_Aggregate then
return True;
-- If component associations remain, the aggregate is not static
elsif Present (Component_Associations (N)) then
return False;
else
One_Dim := First (Expressions (N));
while Present (One_Dim) loop
if Present (Component_Associations (One_Dim)) then
return False;
end if;
One_Comp := First (Expressions (One_Dim));
while Present (One_Comp) loop
if not Is_OK_Static_Expression (One_Comp) then
return False;
end if;
Next (One_Comp);
end loop;
Next (One_Dim);
end loop;
end if;
-- Two-dimensional aggregate is now fully positional so pack one
-- dimension to create a static one-dimensional array, and rewrite
-- as an unchecked conversion to the original type.
declare
Byte_Size : constant Int := UI_To_Int (Component_Size (Packed_Array));
-- The packed array type is a byte array
Packed_Num : Int;
-- Number of components accumulated in current byte
Comps : List_Id;
-- Assembled list of packed values for equivalent aggregate
Comp_Val : Uint;
-- integer value of component
Incr : Int;
-- Step size for packing
Init_Shift : Int;
-- Endian-dependent start position for packing
Shift : Int;
-- Current insertion position
Val : Int;
-- Component of packed array being assembled.
begin
Comps := New_List;
Val := 0;
Packed_Num := 0;
-- Account for endianness. See corresponding comment in
-- Packed_Array_Aggregate_Handled concerning the following.
if Bytes_Big_Endian
xor Debug_Flag_8
xor Reverse_Storage_Order (Base_Type (Typ))
then
Init_Shift := Byte_Size - Comp_Size;
Incr := -Comp_Size;
else
Init_Shift := 0;
Incr := +Comp_Size;
end if;
Shift := Init_Shift;
One_Dim := First (Expressions (N));
-- Iterate over each subaggregate
while Present (One_Dim) loop
One_Comp := First (Expressions (One_Dim));
while Present (One_Comp) loop
if Packed_Num = Byte_Size / Comp_Size then
-- Byte is complete, add to list of expressions
Append (Make_Integer_Literal (Sloc (One_Dim), Val), Comps);
Val := 0;
Shift := Init_Shift;
Packed_Num := 0;
else
Comp_Val := Expr_Rep_Value (One_Comp);
-- Adjust for bias, and strip proper number of bits
if Has_Biased_Representation (Ctyp) then
Comp_Val := Comp_Val - Expr_Value (Type_Low_Bound (Ctyp));
end if;
Comp_Val := Comp_Val mod Uint_2 ** Comp_Size;
Val := UI_To_Int (Val + Comp_Val * Uint_2 ** Shift);
Shift := Shift + Incr;
One_Comp := Next (One_Comp);
Packed_Num := Packed_Num + 1;
end if;
end loop;
One_Dim := Next (One_Dim);
end loop;
if Packed_Num > 0 then
-- Add final incomplete byte if present
Append (Make_Integer_Literal (Sloc (One_Dim), Val), Comps);
end if;
Rewrite (N,
Unchecked_Convert_To (Typ,
Make_Qualified_Expression (Loc,
Subtype_Mark => New_Occurrence_Of (Packed_Array, Loc),
Expression =>
Make_Aggregate (Loc, Expressions => Comps))));
Analyze_And_Resolve (N);
return True;
end;
end Two_Dim_Packed_Array_Handled;
---------------------
-- Sort_Case_Table --
---------------------
procedure Sort_Case_Table (Case_Table : in out Case_Table_Type) is
L : constant Int := Case_Table'First;
U : constant Int := Case_Table'Last;
K : Int;
J : Int;
T : Case_Bounds;
begin
K := L;
while K /= U loop
T := Case_Table (K + 1);
J := K + 1;
while J /= L
and then Expr_Value (Case_Table (J - 1).Choice_Lo) >
Expr_Value (T.Choice_Lo)
loop
Case_Table (J) := Case_Table (J - 1);
J := J - 1;
end loop;
Case_Table (J) := T;
K := K + 1;
end loop;
end Sort_Case_Table;
----------------------------
-- Static_Array_Aggregate --
----------------------------
function Static_Array_Aggregate (N : Node_Id) return Boolean is
Bounds : constant Node_Id := Aggregate_Bounds (N);
Typ : constant Entity_Id := Etype (N);
Comp_Type : constant Entity_Id := Component_Type (Typ);
Agg : Node_Id;
Expr : Node_Id;
Lo : Node_Id;
Hi : Node_Id;
begin
if Is_Tagged_Type (Typ)
or else Is_Controlled (Typ)
or else Is_Packed (Typ)
then
return False;
end if;
if Present (Bounds)
and then Nkind (Bounds) = N_Range
and then Nkind (Low_Bound (Bounds)) = N_Integer_Literal
and then Nkind (High_Bound (Bounds)) = N_Integer_Literal
then
Lo := Low_Bound (Bounds);
Hi := High_Bound (Bounds);
if No (Component_Associations (N)) then
-- Verify that all components are static integers
Expr := First (Expressions (N));
while Present (Expr) loop
if Nkind (Expr) /= N_Integer_Literal then
return False;
end if;
Next (Expr);
end loop;
return True;
else
-- We allow only a single named association, either a static
-- range or an others_clause, with a static expression.
Expr := First (Component_Associations (N));
if Present (Expressions (N)) then
return False;
elsif Present (Next (Expr)) then
return False;
elsif Present (Next (First (Choices (Expr)))) then
return False;
else
-- The aggregate is static if all components are literals,
-- or else all its components are static aggregates for the
-- component type. We also limit the size of a static aggregate
-- to prevent runaway static expressions.
if Is_Array_Type (Comp_Type)
or else Is_Record_Type (Comp_Type)
then
if Nkind (Expression (Expr)) /= N_Aggregate
or else
not Compile_Time_Known_Aggregate (Expression (Expr))
then
return False;
end if;
elsif Nkind (Expression (Expr)) /= N_Integer_Literal then
return False;
end if;
if not Aggr_Size_OK (N, Typ) then
return False;
end if;
-- Create a positional aggregate with the right number of
-- copies of the expression.
Agg := Make_Aggregate (Sloc (N), New_List, No_List);
for I in UI_To_Int (Intval (Lo)) .. UI_To_Int (Intval (Hi))
loop
Append_To
(Expressions (Agg), New_Copy (Expression (Expr)));
-- The copied expression must be analyzed and resolved.
-- Besides setting the type, this ensures that static
-- expressions are appropriately marked as such.
Analyze_And_Resolve
(Last (Expressions (Agg)), Component_Type (Typ));
end loop;
Set_Aggregate_Bounds (Agg, Bounds);
Set_Etype (Agg, Typ);
Set_Analyzed (Agg);
Rewrite (N, Agg);
Set_Compile_Time_Known_Aggregate (N);
return True;
end if;
end if;
else
return False;
end if;
end Static_Array_Aggregate;
end Exp_Aggr;