-- --
-- B o d y --
-- --
--- $Revision$
--- --
--- Copyright (C) 2001 Free Software Foundation, Inc. --
+-- Copyright (C) 2001-2011, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
+-- 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 COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- 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. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Errout; use Errout;
with Exp_Ch3; use Exp_Ch3;
with Exp_Util; use Exp_Util;
+with Namet; use Namet;
with Nlists; use Nlists;
with Nmake; use Nmake;
+with Opt; use Opt;
with Repinfo; use Repinfo;
with Sem; use Sem;
+with Sem_Aux; use Sem_Aux;
with Sem_Ch13; use Sem_Ch13;
with Sem_Eval; use Sem_Eval;
with Sem_Util; use Sem_Util;
-- Local Subprograms --
-----------------------
- procedure Adjust_Esize_Alignment (E : Entity_Id);
- -- E is the entity for a type or object. This procedure checks that the
- -- size and alignment are compatible, and if not either gives an error
- -- message if they cannot be adjusted or else adjusts them appropriately.
-
function Assoc_Add
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id;
+ Right_Opnd : Node_Id) return Node_Id;
-- This is like Make_Op_Add except that it optimizes some cases knowing
-- that associative rearrangement is allowed for constant folding if one
-- of the operands is a compile time known value.
function Assoc_Multiply
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id;
+ Right_Opnd : Node_Id) return Node_Id;
-- This is like Make_Op_Multiply except that it optimizes some cases
- -- knowing that associative rearrangement is allowed for constant
- -- folding if one of the operands is a compile time known value
+ -- knowing that associative rearrangement is allowed for constant folding
+ -- if one of the operands is a compile time known value
function Assoc_Subtract
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id;
+ Right_Opnd : Node_Id) return Node_Id;
-- This is like Make_Op_Subtract except that it optimizes some cases
- -- knowing that associative rearrangement is allowed for constant
- -- folding if one of the operands is a compile time known value
+ -- knowing that associative rearrangement is allowed for constant folding
+ -- if one of the operands is a compile time known value
+
+ function Bits_To_SU (N : Node_Id) return Node_Id;
+ -- This is used when we cross the boundary from static sizes in bits to
+ -- dynamic sizes in storage units. If the argument N is anything other
+ -- than an integer literal, it is returned unchanged, but if it is an
+ -- integer literal, then it is taken as a size in bits, and is replaced
+ -- by the corresponding size in storage units.
function Compute_Length (Lo : Node_Id; Hi : Node_Id) return Node_Id;
-- Given expressions for the low bound (Lo) and the high bound (Hi),
-- are of an enumeration type (so that the subtraction cannot be
-- done directly) by applying the Pos operator to Hi/Lo first.
+ procedure Compute_Size_Depends_On_Discriminant (E : Entity_Id);
+ -- Given an array type or an array subtype E, compute whether its size
+ -- depends on the value of one or more discriminants and set the flag
+ -- Size_Depends_On_Discriminant accordingly. This need not be called
+ -- in front end layout mode since it does the computation on its own.
+
function Expr_From_SO_Ref
(Loc : Source_Ptr;
- D : SO_Ref)
- return Node_Id;
+ D : SO_Ref;
+ Comp : Entity_Id := Empty) return Node_Id;
-- Given a value D from a size or offset field, return an expression
-- representing the value stored. If the value is known at compile time,
-- then an N_Integer_Literal is returned with the appropriate value. If
-- the value references a constant entity, then an N_Identifier node
- -- referencing this entity is returned. The Loc value is used for the
- -- Sloc value of constructed notes.
+ -- referencing this entity is returned. If the value denotes a size
+ -- function, then returns a call node denoting the given function, with
+ -- a single actual parameter that either refers to the parameter V of
+ -- an enclosing size function (if Comp is Empty or its type doesn't match
+ -- the function's formal), or else is a selected component V.c when Comp
+ -- denotes a component c whose type matches that of the function formal.
+ -- The Loc value is used for the Sloc value of constructed notes.
function SO_Ref_From_Expr
(Expr : Node_Id;
Ins_Type : Entity_Id;
- Vtype : Entity_Id := Empty)
- return Dynamic_SO_Ref;
+ Vtype : Entity_Id := Empty;
+ Make_Func : Boolean := False) return Dynamic_SO_Ref;
-- This routine is used in the case where a size/offset value is dynamic
-- and is represented by the expression Expr. SO_Ref_From_Expr checks if
-- the Expr contains a reference to the identifier V, and if so builds
-- a function depending on discriminants of the formal parameter V which
- -- is of type Vtype. If not, then a constant entity with the value Expr
- -- is built. The result is a Dynamic_SO_Ref to the created entity. Note
- -- that Vtype can be omitted if Expr does not contain any reference to V.
- -- the created entity. The declaration created is inserted in the freeze
- -- actions of Ins_Type, which also supplies the Sloc for created nodes.
- -- This function also takes care of making sure that the expression is
- -- properly analyzed and resolved (which may not be the case yet if we
- -- build the expression in this unit).
-
- function Get_Max_Size (E : Entity_Id) return Node_Id;
+ -- is of type Vtype. Otherwise, if the parameter Make_Func is True, then
+ -- Expr will be encapsulated in a parameterless function; if Make_Func is
+ -- False, then a constant entity with the value Expr is built. The result
+ -- is a Dynamic_SO_Ref to the created entity. Note that Vtype can be
+ -- omitted if Expr does not contain any reference to V, the created entity.
+ -- The declaration created is inserted in the freeze actions of Ins_Type,
+ -- which also supplies the Sloc for created nodes. This function also takes
+ -- care of making sure that the expression is properly analyzed and
+ -- resolved (which may not be the case yet if we build the expression
+ -- in this unit).
+
+ function Get_Max_SU_Size (E : Entity_Id) return Node_Id;
-- E is an array type or subtype that has at least one index bound that
-- is the value of a record discriminant. For such an array, the function
-- computes an expression that yields the maximum possible size of the
-- array in storage units. The result is not defined for any other type,
-- or for arrays that do not depend on discriminants, and it is a fatal
- -- error to call this unless Size_Depends_On_Discrminant (E) is True.
+ -- error to call this unless Size_Depends_On_Discriminant (E) is True.
procedure Layout_Array_Type (E : Entity_Id);
- -- Front end layout of non-bit-packed array type or subtype
+ -- Front-end layout of non-bit-packed array type or subtype
procedure Layout_Record_Type (E : Entity_Id);
- -- Front end layout of record type
- -- Variant records not handled yet ???
+ -- Front-end layout of record type
procedure Rewrite_Integer (N : Node_Id; V : Uint);
- -- Rewrite node N with an integer literal whose value is V. The Sloc
- -- for the new node is taken from N, and the type of the literal is
- -- set to a copy of the type of N on entry.
+ -- Rewrite node N with an integer literal whose value is V. The Sloc for
+ -- the new node is taken from N, and the type of the literal is set to a
+ -- copy of the type of N on entry.
procedure Set_And_Check_Static_Size
(E : Entity_Id;
Esiz : SO_Ref;
RM_Siz : SO_Ref);
- -- This procedure is called to check explicit given sizes (possibly
- -- stored in the Esize and RM_Size fields of E) against computed
- -- Object_Size (Esiz) and Value_Size (RM_Siz) values. Appropriate
- -- errors and warnings are posted if specified sizes are inconsistent
- -- with specified sizes. On return, the Esize and RM_Size fields of
- -- E are set (either from previously given values, or from the newly
- -- computed values, as appropriate).
+ -- This procedure is called to check explicit given sizes (possibly stored
+ -- in the Esize and RM_Size fields of E) against computed Object_Size
+ -- (Esiz) and Value_Size (RM_Siz) values. Appropriate errors and warnings
+ -- are posted if specified sizes are inconsistent with specified sizes. On
+ -- return, Esize and RM_Size fields of E are set (either from previously
+ -- given values, or from the newly computed values, as appropriate).
+
+ procedure Set_Composite_Alignment (E : Entity_Id);
+ -- This procedure is called for record types and subtypes, and also for
+ -- atomic array types and subtypes. If no alignment is set, and the size
+ -- is 2 or 4 (or 8 if the word size is 8), then the alignment is set to
+ -- match the size.
----------------------------
-- Adjust_Esize_Alignment --
-- which must be obeyed. If so, we cannot increase the size in this
-- routine.
- -- For a type, the issue is whether an object size clause has been
- -- set. A normal size clause constrains only the value size (RM_Size)
+ -- For a type, the issue is whether an object size clause has been set.
+ -- A normal size clause constrains only the value size (RM_Size)
if Is_Type (E) then
Esize_Set := Has_Object_Size_Clause (E);
Esize_Set := Has_Size_Clause (E);
end if;
- -- If size is known it must be a multiple of the byte size
+ -- If size is known it must be a multiple of the storage unit size
if Esize (E) mod SSU /= 0 then
if Esize_Set then
Error_Msg_NE
- ("size for& not a multiple of byte size", Size_Clause (E), E);
+ ("size for& not a multiple of storage unit size",
+ Size_Clause (E), E);
return;
- -- Otherwise bump up size to a byte boundary
+ -- Otherwise bump up size to a storage unit boundary
else
Set_Esize (E, (Esize (E) + SSU - 1) / SSU * SSU);
return;
end if;
- -- Here we have a situation where the Esize is not a multiple of
- -- the alignment. We must either increase Esize or reduce the
- -- alignment to correct this situation.
+ -- Here we have a situation where the Esize is not a multiple of the
+ -- alignment. We must either increase Esize or reduce the alignment to
+ -- correct this situation.
-- The case in which we can decrease the alignment is where the
-- alignment was not set by an alignment clause, and the type in
- -- question is a discrete type, where it is definitely safe to
- -- reduce the alignment. For example:
+ -- question is a discrete type, where it is definitely safe to reduce
+ -- the alignment. For example:
-- t : integer range 1 .. 2;
-- for t'size use 8;
-- In this situation, the initial alignment of t is 4, copied from
-- the Integer base type, but it is safe to reduce it to 1 at this
- -- stage, since we will only be loading a single byte.
+ -- stage, since we will only be loading a single storage unit.
if Is_Discrete_Type (Etype (E))
and then not Has_Alignment_Clause (E)
return;
end if;
- -- Now the only possible approach left is to increase the Esize
- -- but we can't do that if the size was set by a specific clause.
+ -- Now the only possible approach left is to increase the Esize but we
+ -- can't do that if the size was set by a specific clause.
if Esize_Set then
Error_Msg_NE
function Assoc_Add
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id
+ Right_Opnd : Node_Id) return Node_Id
is
L : Node_Id;
R : Uint;
function Assoc_Multiply
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id
+ Right_Opnd : Node_Id) return Node_Id
is
L : Node_Id;
R : Uint;
function Assoc_Subtract
(Loc : Source_Ptr;
Left_Opnd : Node_Id;
- Right_Opnd : Node_Id)
- return Node_Id
+ Right_Opnd : Node_Id) return Node_Id
is
L : Node_Id;
R : Uint;
return Make_Op_Subtract (Loc, Left_Opnd, Right_Opnd);
end Assoc_Subtract;
+ ----------------
+ -- Bits_To_SU --
+ ----------------
+
+ function Bits_To_SU (N : Node_Id) return Node_Id is
+ begin
+ if Nkind (N) = N_Integer_Literal then
+ Set_Intval (N, (Intval (N) + (SSU - 1)) / SSU);
+ end if;
+
+ return N;
+ end Bits_To_SU;
+
--------------------
-- Compute_Length --
--------------------
function Compute_Length (Lo : Node_Id; Hi : Node_Id) return Node_Id is
- Loc : constant Source_Ptr := Sloc (Lo);
- Typ : constant Entity_Id := Etype (Lo);
- Lo_Op : Node_Id;
- Hi_Op : Node_Id;
+ Loc : constant Source_Ptr := Sloc (Lo);
+ Typ : constant Entity_Id := Etype (Lo);
+ Lo_Op : Node_Id;
+ Hi_Op : Node_Id;
+ Lo_Dim : Uint;
+ Hi_Dim : Uint;
begin
+ -- If the bounds are First and Last attributes for the same dimension
+ -- and both have prefixes that denotes the same entity, then we create
+ -- and return a Length attribute. This may allow the back end to
+ -- generate better code in cases where it already has the length.
+
+ if Nkind (Lo) = N_Attribute_Reference
+ and then Attribute_Name (Lo) = Name_First
+ and then Nkind (Hi) = N_Attribute_Reference
+ and then Attribute_Name (Hi) = Name_Last
+ and then Is_Entity_Name (Prefix (Lo))
+ and then Is_Entity_Name (Prefix (Hi))
+ and then Entity (Prefix (Lo)) = Entity (Prefix (Hi))
+ then
+ Lo_Dim := Uint_1;
+ Hi_Dim := Uint_1;
+
+ if Present (First (Expressions (Lo))) then
+ Lo_Dim := Expr_Value (First (Expressions (Lo)));
+ end if;
+
+ if Present (First (Expressions (Hi))) then
+ Hi_Dim := Expr_Value (First (Expressions (Hi)));
+ end if;
+
+ if Lo_Dim = Hi_Dim then
+ return
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of
+ (Entity (Prefix (Lo)), Loc),
+ Attribute_Name => Name_Length,
+ Expressions => New_List
+ (Make_Integer_Literal (Loc, Lo_Dim)));
+ end if;
+ end if;
+
Lo_Op := New_Copy_Tree (Lo);
Hi_Op := New_Copy_Tree (Hi);
function Expr_From_SO_Ref
(Loc : Source_Ptr;
- D : SO_Ref)
- return Node_Id
+ D : SO_Ref;
+ Comp : Entity_Id := Empty) return Node_Id
is
Ent : Entity_Id;
Ent := Get_Dynamic_SO_Entity (D);
if Is_Discrim_SO_Function (Ent) then
- return
- Make_Function_Call (Loc,
- Name => New_Occurrence_Of (Ent, Loc),
- Parameter_Associations => New_List (
- Make_Identifier (Loc, Chars => Vname)));
+
+ -- If a component is passed in whose type matches the type of
+ -- the function formal, then select that component from the "V"
+ -- parameter rather than passing "V" directly.
+
+ if Present (Comp)
+ and then Base_Type (Etype (Comp))
+ = Base_Type (Etype (First_Formal (Ent)))
+ then
+ return
+ Make_Function_Call (Loc,
+ Name => New_Occurrence_Of (Ent, Loc),
+ Parameter_Associations => New_List (
+ Make_Selected_Component (Loc,
+ Prefix => Make_Identifier (Loc, Vname),
+ Selector_Name => New_Occurrence_Of (Comp, Loc))));
+
+ else
+ return
+ Make_Function_Call (Loc,
+ Name => New_Occurrence_Of (Ent, Loc),
+ Parameter_Associations => New_List (
+ Make_Identifier (Loc, Vname)));
+ end if;
else
return New_Occurrence_Of (Ent, Loc);
end if;
end Expr_From_SO_Ref;
- ------------------
- -- Get_Max_Size --
- ------------------
+ ---------------------
+ -- Get_Max_SU_Size --
+ ---------------------
- function Get_Max_Size (E : Entity_Id) return Node_Id is
+ function Get_Max_SU_Size (E : Entity_Id) return Node_Id is
Loc : constant Source_Ptr := Sloc (E);
Indx : Node_Id;
Ityp : Entity_Id;
when Dynamic => Nod : Node_Id;
end case;
end record;
- -- Shows the status of the value so far. Const means that the value
- -- is constant, and Val is the current constant value. Dynamic means
- -- that the value is dynamic, and in this case Nod is the Node_Id of
- -- the expression to compute the value.
+ -- Shows the status of the value so far. Const means that the value is
+ -- constant, and Val is the current constant value. Dynamic means that
+ -- the value is dynamic, and in this case Nod is the Node_Id of the
+ -- expression to compute the value.
Size : Val_Type;
-- Calculated value so far if Size.Status = Const,
-- or expression value so far if Size.Status = Dynamic.
SU_Convert_Required : Boolean := False;
- -- This is set to True if the final result must be converted from
- -- bits to storage units (rounding up to a storage unit boundary).
+ -- This is set to True if the final result must be converted from bits
+ -- to storage units (rounding up to a storage unit boundary).
-----------------------
-- Local Subprograms --
end if;
end Min_Discrim;
- -- Start of processing for Get_Max_Size
+ -- Start of processing for Get_Max_SU_Size
begin
pragma Assert (Size_Depends_On_Discriminant (E));
Size := (Dynamic, Expr_From_SO_Ref (Loc, Component_Size (E)));
end if;
- -- Loop through indices
+ -- Loop through indexes
Indx := First_Index (E);
while Present (Indx) loop
(Dynamic, Make_Integer_Literal (Loc, Size.Val / SSU));
SU_Convert_Required := False;
- -- Otherwise, we go ahead and convert the value in bits,
- -- and set SU_Convert_Required to True to ensure that the
- -- final value is indeed properly converted.
+ -- Otherwise, we go ahead and convert the value in bits, and
+ -- set SU_Convert_Required to True to ensure that the final
+ -- value is indeed properly converted.
else
Size := (Dynamic, Make_Integer_Literal (Loc, Size.Val));
OK : Boolean;
LLo : Uint;
LHi : Uint;
+ pragma Warnings (Off, LHi);
begin
Set_Parent (Len, E);
Len := Convert_To (Standard_Unsigned, Len);
- -- If we cannot verify that range cannot be super-flat,
- -- we need a max with zero, since length must be non-neg.
+ -- If we cannot verify that range cannot be super-flat, we need
+ -- a max with zero, since length must be non-negative.
if not OK or else LLo < 0 then
Len :=
Next_Index (Indx);
end loop;
- -- Here after processing all bounds to set sizes. If the value is
- -- a constant, then it is bits, and we just return the value.
+ -- Here after processing all bounds to set sizes. If the value is a
+ -- constant, then it is bits, so we convert to storage units.
if Size.Status = Const then
- return Make_Integer_Literal (Loc, Size.Val);
+ return Bits_To_SU (Make_Integer_Literal (Loc, Size.Val));
-- Case where the value is dynamic
return Size.Nod;
end if;
- end Get_Max_Size;
+ end Get_Max_SU_Size;
-----------------------
-- Layout_Array_Type --
Insert_Typ : Entity_Id;
-- This is the type with which any generated constants or functions
-- will be associated (i.e. inserted into the freeze actions). This
- -- is normally the type being layed out. The exception occurs when
+ -- is normally the type being laid out. The exception occurs when
-- we are laying out Itype's which are local to a record type, and
-- whose scope is this record type. Such types do not have freeze
-- nodes (because we have no place to put them).
------------------------------------
- -- How An Array Type is Layed Out --
+ -- How An Array Type is Laid Out --
------------------------------------
- -- Here is what goes on. We need to multiply the component size of
- -- the array (which has already been set) by the length of each of
- -- the indexes. If all these values are known at compile time, then
- -- the resulting size of the array is the appropriate constant value.
+ -- Here is what goes on. We need to multiply the component size of the
+ -- array (which has already been set) by the length of each of the
+ -- indexes. If all these values are known at compile time, then the
+ -- resulting size of the array is the appropriate constant value.
-- If the component size or at least one bound is dynamic (but no
-- discriminants are present), then the size will be computed as an
-- is the expression so far (which will be the body of the function).
Size : Val_Type;
- -- Value of size computed so far. See comments above.
+ -- Value of size computed so far. See comments above
Vtyp : Entity_Id := Empty;
- -- Variant record type for the formal parameter of the
- -- discriminant function V if Status = Discrim.
+ -- Variant record type for the formal parameter of the discriminant
+ -- function V if Status = Discrim.
SU_Convert_Required : Boolean := False;
-- This is set to True if the final result must be converted from
-- bits to storage units (rounding up to a storage unit boundary).
+ Storage_Divisor : Uint := UI_From_Int (SSU);
+ -- This is the amount that a nonstatic computed size will be divided
+ -- by to convert it from bits to storage units. This is normally
+ -- equal to SSU, but can be reduced in the case of packed components
+ -- that fit evenly into a storage unit.
+
+ Make_Size_Function : Boolean := False;
+ -- Indicates whether to request that SO_Ref_From_Expr should
+ -- encapsulate the array size expression in a function.
+
procedure Discrimify (N : in out Node_Id);
-- If N represents a discriminant, then the Size.Status is set to
-- Discrim, and Vtyp is set. The parameter N is replaced with the
N :=
Make_Selected_Component (Loc,
- Prefix => Make_Identifier (Loc, Chars => Vname),
+ Prefix => Make_Identifier (Loc, Vname),
Selector_Name => New_Occurrence_Of (Entity (N), Loc));
-- Set the Etype attributes of the selected name and its prefix.
-- Calculate proper type for insertions
- if Is_Record_Type (Scope (E)) then
- Insert_Typ := Scope (E);
+ if Is_Record_Type (Underlying_Type (Scope (E))) then
+ Insert_Typ := Underlying_Type (Scope (E));
else
Insert_Typ := E;
end if;
- -- Cannot do anything if Esize of component type unknown
+ -- If the component type is a generic formal type then there's no point
+ -- in determining a size for the array type.
- if Unknown_Esize (Ctyp) then
+ if Is_Generic_Type (Ctyp) then
return;
end if;
- -- Set component size if not set already
+ -- Deal with component size if base type
+
+ if Ekind (E) = E_Array_Type then
- if Unknown_Component_Size (E) then
- Set_Component_Size (E, Esize (Ctyp));
+ -- Cannot do anything if Esize of component type unknown
+
+ if Unknown_Esize (Ctyp) then
+ return;
+ end if;
+
+ -- Set component size if not set already
+
+ if Unknown_Component_Size (E) then
+ Set_Component_Size (E, Esize (Ctyp));
+ end if;
end if;
-- (RM 13.3 (48)) says that the size of an unconstrained array
Size := (Dynamic, Expr_From_SO_Ref (Loc, Component_Size (E)));
end if;
- -- Loop to process array indices
+ -- Loop to process array indexes
Indx := First_Index (E);
while Present (Indx) loop
Ityp := Etype (Indx);
+
+ -- If an index of the array is a generic formal type then there is
+ -- no point in determining a size for the array type.
+
+ if Is_Generic_Type (Ityp) then
+ return;
+ end if;
+
Lo := Type_Low_Bound (Ityp);
Hi := Type_High_Bound (Ityp);
(Dynamic, Make_Integer_Literal (Loc, Size.Val / SSU));
SU_Convert_Required := False;
- -- Otherwise, we go ahead and convert the value in bits,
- -- and set SU_Convert_Required to True to ensure that the
- -- final value is indeed properly converted.
+ -- If the current value is a factor of the storage unit, then
+ -- we can use a value of one for the size and reduce the
+ -- strength of the later division.
+
+ elsif SSU mod Size.Val = 0 then
+ Storage_Divisor := SSU / Size.Val;
+ Size := (Dynamic, Make_Integer_Literal (Loc, Uint_1));
+ SU_Convert_Required := True;
+
+ -- Otherwise, we go ahead and convert the value in bits, and
+ -- set SU_Convert_Required to True to ensure that the final
+ -- value is indeed properly converted.
else
Size := (Dynamic, Make_Integer_Literal (Loc, Size.Val));
Len := Compute_Length (Lo, Hi);
- -- Check possible range of Len
+ -- If Len isn't a Length attribute, then its range needs to be
+ -- checked a possible Max with zero needs to be computed.
- declare
- OK : Boolean;
- LLo : Uint;
- LHi : Uint;
+ if Nkind (Len) /= N_Attribute_Reference
+ or else Attribute_Name (Len) /= Name_Length
+ then
+ declare
+ OK : Boolean;
+ LLo : Uint;
+ LHi : Uint;
- begin
- Set_Parent (Len, E);
- Determine_Range (Len, OK, LLo, LHi);
+ begin
+ -- Check possible range of Len
- Len := Convert_To (Standard_Unsigned, Len);
+ Set_Parent (Len, E);
+ Determine_Range (Len, OK, LLo, LHi);
- -- If range definitely flat or superflat, result size is zero
+ Len := Convert_To (Standard_Unsigned, Len);
- if OK and then LHi <= 0 then
- Set_Esize (E, Uint_0);
- Set_RM_Size (E, Uint_0);
- return;
- end if;
+ -- If range definitely flat or superflat,
+ -- result size is zero
- -- If we cannot verify that range cannot be super-flat, we
- -- need a maximum with zero, since length cannot be negative.
+ if OK and then LHi <= 0 then
+ Set_Esize (E, Uint_0);
+ Set_RM_Size (E, Uint_0);
+ return;
+ end if;
- if not OK or else LLo < 0 then
- Len :=
- Make_Attribute_Reference (Loc,
- Prefix =>
- New_Occurrence_Of (Standard_Unsigned, Loc),
- Attribute_Name => Name_Max,
- Expressions => New_List (
- Make_Integer_Literal (Loc, 0),
- Len));
- end if;
- end;
+ -- If we cannot verify that range cannot be super-flat, we
+ -- need a max with zero, since length cannot be negative.
+
+ if not OK or else LLo < 0 then
+ Len :=
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Occurrence_Of (Standard_Unsigned, Loc),
+ Attribute_Name => Name_Max,
+ Expressions => New_List (
+ Make_Integer_Literal (Loc, 0),
+ Len));
+ end if;
+ end;
+ end if;
-- At this stage, Len has the expression for the length
Next_Index (Indx);
end loop;
- -- Here after processing all bounds to set sizes. If the value is
- -- a constant, then it is bits, and the only thing we need to do
- -- is to check against explicit given size and do alignment adjust.
+ -- Here after processing all bounds to set sizes. If the value is a
+ -- constant, then it is bits, and the only thing we need to do is to
+ -- check against explicit given size and do alignment adjust.
if Size.Status = Const then
Set_And_Check_Static_Size (E, Size.Val, Size.Val);
if SU_Convert_Required then
- -- The expression required is (Size.Nod + SU - 1) / SU
+ -- The expression required is:
+ -- (Size.Nod + Storage_Divisor - 1) / Storage_Divisor
Size.Nod :=
Make_Op_Divide (Loc,
Left_Opnd =>
Make_Op_Add (Loc,
Left_Opnd => Size.Nod,
- Right_Opnd => Make_Integer_Literal (Loc, SSU - 1)),
- Right_Opnd => Make_Integer_Literal (Loc, SSU));
+ Right_Opnd => Make_Integer_Literal
+ (Loc, Storage_Divisor - 1)),
+ Right_Opnd => Make_Integer_Literal (Loc, Storage_Divisor));
end if;
- -- Now set the dynamic size (the Value_Size is always the same
- -- as the Object_Size for arrays whose length is dynamic).
+ -- If the array entity is not declared at the library level and its
+ -- not nested within a subprogram that is marked for inlining, then
+ -- we request that the size expression be encapsulated in a function.
+ -- Since this expression is not needed in most cases, we prefer not
+ -- to incur the overhead of the computation on calls to the enclosing
+ -- subprogram except for subprograms that require the size.
+
+ if not Is_Library_Level_Entity (E) then
+ Make_Size_Function := True;
+
+ declare
+ Parent_Subp : Entity_Id := Enclosing_Subprogram (E);
+
+ begin
+ while Present (Parent_Subp) loop
+ if Is_Inlined (Parent_Subp) then
+ Make_Size_Function := False;
+ exit;
+ end if;
+
+ Parent_Subp := Enclosing_Subprogram (Parent_Subp);
+ end loop;
+ end;
+ end if;
+
+ -- Now set the dynamic size (the Value_Size is always the same as the
+ -- Object_Size for arrays whose length is dynamic).
-- ??? If Size.Status = Dynamic, Vtyp will not have been set.
-- The added initialization sets it to Empty now, but is this
-- correct?
- Set_Esize (E, SO_Ref_From_Expr (Size.Nod, Insert_Typ, Vtyp));
+ Set_Esize
+ (E,
+ SO_Ref_From_Expr
+ (Size.Nod, Insert_Typ, Vtyp, Make_Func => Make_Size_Function));
Set_RM_Size (E, Esize (E));
end if;
end Layout_Array_Type;
+ ------------------------------------------
+ -- Compute_Size_Depends_On_Discriminant --
+ ------------------------------------------
+
+ procedure Compute_Size_Depends_On_Discriminant (E : Entity_Id) is
+ Indx : Node_Id;
+ Ityp : Entity_Id;
+ Lo : Node_Id;
+ Hi : Node_Id;
+ Res : Boolean := False;
+
+ begin
+ -- Loop to process array indexes
+
+ Indx := First_Index (E);
+ while Present (Indx) loop
+ Ityp := Etype (Indx);
+
+ -- If an index of the array is a generic formal type then there is
+ -- no point in determining a size for the array type.
+
+ if Is_Generic_Type (Ityp) then
+ return;
+ end if;
+
+ Lo := Type_Low_Bound (Ityp);
+ Hi := Type_High_Bound (Ityp);
+
+ if (Nkind (Lo) = N_Identifier
+ and then Ekind (Entity (Lo)) = E_Discriminant)
+ or else
+ (Nkind (Hi) = N_Identifier
+ and then Ekind (Entity (Hi)) = E_Discriminant)
+ then
+ Res := True;
+ end if;
+
+ Next_Index (Indx);
+ end loop;
+
+ if Res then
+ Set_Size_Depends_On_Discriminant (E);
+ end if;
+ end Compute_Size_Depends_On_Discriminant;
+
-------------------
-- Layout_Object --
-------------------
return;
end if;
- -- Set size if not set for object and known for type. Use the
- -- RM_Size if that is known for the type and Esize is not.
+ -- Set size if not set for object and known for type. Use the RM_Size if
+ -- that is known for the type and Esize is not.
if Unknown_Esize (E) then
if Known_Esize (T) then
Adjust_Esize_Alignment (E);
- -- Final adjustment, if we don't know the alignment, and the Esize
- -- was not set by an explicit Object_Size attribute clause, then
- -- we reset the Esize to unknown, since we really don't know it.
+ -- Final adjustment, if we don't know the alignment, and the Esize was
+ -- not set by an explicit Object_Size attribute clause, then we reset
+ -- the Esize to unknown, since we really don't know it.
if Unknown_Alignment (E)
and then not Has_Size_Clause (E)
Decl : Node_Id;
Comp : Entity_Id;
- -- Current component being layed out
+ -- Current component being laid out
Prev_Comp : Entity_Id;
- -- Previous layed out component
+ -- Previous laid out component
procedure Get_Next_Component_Location
(Prev_Comp : Entity_Id;
-- Lays out component Comp, given Prev_Comp, the previously laid-out
-- component (Prev_Comp = Empty if no components laid out yet). The
-- alignment of the record itself is also updated if needed. Both
- -- Comp and Prev_Comp can be either components or discriminants. A
- -- special case is when Comp is Empty, this is used at the end
- -- to determine the size of the entire record. For this special
- -- call the resulting offset is placed in Final_Offset.
+ -- Comp and Prev_Comp can be either components or discriminants.
procedure Layout_Components
(From : Entity_Id;
Esiz : out SO_Ref;
RM_Siz : out SO_Ref);
-- This procedure lays out the components of the given component list
- -- which contains the components starting with From, and ending with To.
- -- The Next_Entity chain is used to traverse the components. On entry
+ -- which contains the components starting with From and ending with To.
+ -- The Next_Entity chain is used to traverse the components. On entry,
-- Prev_Comp is set to the component preceding the list, so that the
- -- list is layed out after this component. Prev_Comp is set to Empty if
- -- the component list is to be layed out starting at the start of the
- -- record. On return, the components are all layed out, and Prev_Comp is
- -- set to the last layed out component. On return, Esiz is set to the
+ -- list is laid out after this component. Prev_Comp is set to Empty if
+ -- the component list is to be laid out starting at the start of the
+ -- record. On return, the components are all laid out, and Prev_Comp is
+ -- set to the last laid out component. On return, Esiz is set to the
-- resulting Object_Size value, which is the length of the record up
- -- to and including the last layed out entity. For Esiz, the value is
+ -- to and including the last laid out entity. For Esiz, the value is
-- adjusted to match the alignment of the record. RM_Siz is similarly
-- set to the resulting Value_Size value, which is the same length, but
-- not adjusted to meet the alignment. Note that in the case of variant
-- records, Esiz represents the maximum size.
procedure Layout_Non_Variant_Record;
- -- Procedure called to layout a non-variant record type or subtype
+ -- Procedure called to lay out a non-variant record type or subtype
procedure Layout_Variant_Record;
- -- Procedure called to layout a variant record type. Decl is set to the
+ -- Procedure called to lay out a variant record type. Decl is set to the
-- full type declaration for the variant record.
---------------------------------
New_Npos :=
SO_Ref_From_Expr
(Assoc_Add (Loc,
- Left_Opnd => Expr_From_SO_Ref (Loc, Old_Npos),
- Right_Opnd => Expr_From_SO_Ref (Loc, Old_Esiz)),
+ Left_Opnd =>
+ Expr_From_SO_Ref (Loc, Old_Npos),
+ Right_Opnd =>
+ Expr_From_SO_Ref (Loc, Old_Esiz, Prev_Comp)),
Ins_Type => E,
Vtype => E);
-- Get maximum size of previous component
if Size_Depends_On_Discriminant (Etype (Prev_Comp)) then
- Old_Maxsz := Get_Max_Size (Etype (Prev_Comp));
+ Old_Maxsz := Get_Max_SU_Size (Etype (Prev_Comp));
else
- Old_Maxsz := Expr_From_SO_Ref (Loc, Old_Esiz);
+ Old_Maxsz := Expr_From_SO_Ref (Loc, Old_Esiz, Prev_Comp);
end if;
-- Now we can compute the new max position. If the max size
New_Fbit := (New_Fbit + SSU - 1) / SSU * SSU;
end if;
- -- If old normalized position is static, we can go ahead
- -- and compute the new normalized position directly.
+ -- If old normalized position is static, we can go ahead and
+ -- compute the new normalized position directly.
if Known_Static_Normalized_Position (Prev_Comp) then
New_Npos := Old_Npos;
-- Bump alignment if stricter than prev
- if Align > Alignment (Prev_Comp) then
+ if Align > Alignment (Etype (Prev_Comp)) then
New_Npos := (New_Npos + Align - 1) / Align * Align;
end if;
procedure Layout_Component (Comp : Entity_Id; Prev_Comp : Entity_Id) is
Ctyp : constant Entity_Id := Etype (Comp);
+ ORC : constant Entity_Id := Original_Record_Component (Comp);
Npos : SO_Ref;
Fbit : SO_Ref;
NPMax : SO_Ref;
Forc : Boolean;
begin
+ -- Increase alignment of record if necessary. Note that we do not
+ -- do this for packed records, which have an alignment of one by
+ -- default, or for records for which an explicit alignment was
+ -- specified with an alignment clause.
+
+ if not Is_Packed (E)
+ and then not Has_Alignment_Clause (E)
+ and then Alignment (Ctyp) > Alignment (E)
+ then
+ Set_Alignment (E, Alignment (Ctyp));
+ end if;
+
+ -- If original component set, then use same layout
+
+ if Present (ORC) and then ORC /= Comp then
+ Set_Normalized_Position (Comp, Normalized_Position (ORC));
+ Set_Normalized_First_Bit (Comp, Normalized_First_Bit (ORC));
+ Set_Normalized_Position_Max (Comp, Normalized_Position_Max (ORC));
+ Set_Component_Bit_Offset (Comp, Component_Bit_Offset (ORC));
+ Set_Esize (Comp, Esize (ORC));
+ return;
+ end if;
+
-- Parent field is always at start of record, this will overlap
-- the actual fields that are part of the parent, and that's fine
return;
end if;
- -- Check case of type of component has a scope of the record we
- -- are laying out. When this happens, the type in question is an
- -- Itype that has not yet been layed out (that's because such
- -- types do not get frozen in the normal manner, because there
- -- is no place for the freeze nodes).
+ -- Check case of type of component has a scope of the record we are
+ -- laying out. When this happens, the type in question is an Itype
+ -- that has not yet been laid out (that's because such types do not
+ -- get frozen in the normal manner, because there is no place for
+ -- the freeze nodes).
if Scope (Ctyp) = E then
Layout_Type (Ctyp);
end if;
- -- Increase alignment of record if necessary. Note that we do not
- -- do this for packed records, which have an alignment of one by
- -- default, or for records for which an explicit alignment was
- -- specified with an alignment clause.
-
- if not Is_Packed (E)
- and then not Has_Alignment_Clause (E)
- and then Alignment (Ctyp) > Alignment (E)
- then
- Set_Alignment (E, Alignment (Ctyp));
- end if;
-
-- If component already laid out, then we are done
if Known_Normalized_Position (Comp) then
end if;
-- Set size of component from type. We use the Esize except in a
- -- packed record, where we use the RM_Size (since that is exactly
- -- what the RM_Size value, as distinct from the Object_Size is
- -- useful for!)
+ -- packed record, where we use the RM_Size (since that is what the
+ -- RM_Size value, as distinct from the Object_Size is useful for!)
if Is_Packed (E) then
Set_Esize (Comp, RM_Size (Ctyp));
End_NPMax : SO_Ref;
begin
- -- Only layout components if there are some to layout!
+ -- Only lay out components if there are some to lay out!
if Present (From) then
- -- Layout components with no component clauses
+ -- Lay out components with no component clauses
Comp := From;
loop
- if (Ekind (Comp) = E_Component
- or else Ekind (Comp) = E_Discriminant)
- and then No (Component_Clause (Comp))
+ if Ekind (Comp) = E_Component
+ or else Ekind (Comp) = E_Discriminant
then
- Layout_Component (Comp, Prev_Comp);
- Prev_Comp := Comp;
+ -- The compatibility of component clauses with composite
+ -- types isn't checked in Sem_Ch13, so we check it here.
+
+ if Present (Component_Clause (Comp)) then
+ if Is_Composite_Type (Etype (Comp))
+ and then Esize (Comp) < RM_Size (Etype (Comp))
+ then
+ Error_Msg_Uint_1 := RM_Size (Etype (Comp));
+ Error_Msg_NE
+ ("size for & too small, minimum allowed is ^",
+ Component_Clause (Comp),
+ Comp);
+ end if;
+
+ else
+ Layout_Component (Comp, Prev_Comp);
+ Prev_Comp := Comp;
+ end if;
end if;
exit when Comp = To;
Esiz := Uint_0;
RM_Siz := Uint_0;
+ -- If record subtype with non-static discriminants, then we don't
+ -- know which variant will be the one which gets chosen. We don't
+ -- just want to set the maximum size from the base, because the
+ -- size should depend on the particular variant.
+
+ -- What we do is to use the RM_Size of the base type, which has
+ -- the necessary conditional computation of the size, using the
+ -- size information for the particular variant chosen. Records
+ -- with default discriminants for example have an Esize that is
+ -- set to the maximum of all variants, but that's not what we
+ -- want for a constrained subtype.
+
+ elsif Ekind (E) = E_Record_Subtype
+ and then not Has_Static_Discriminants (E)
+ then
+ declare
+ BT : constant Node_Id := Base_Type (E);
+ begin
+ Esiz := RM_Size (BT);
+ RM_Siz := RM_Size (BT);
+ Set_Alignment (E, Alignment (BT));
+ end;
+
else
- -- First the object size, for which we align past the last
- -- field to the alignment of the record (the object size
- -- is required to be a multiple of the alignment).
+ -- First the object size, for which we align past the last field
+ -- to the alignment of the record (the object size is required to
+ -- be a multiple of the alignment).
Get_Next_Component_Location
(Prev_Comp,
Force_SU => True);
-- If the resulting normalized position is a dynamic reference,
- -- then the size is dynamic, and is stored in storage units.
- -- In this case, we set the RM_Size to the same value, it is
- -- simply not worth distinguishing Esize and RM_Size values in
- -- the dynamic case, since the RM has nothing to say about them.
+ -- then the size is dynamic, and is stored in storage units. In
+ -- this case, we set the RM_Size to the same value, it is simply
+ -- not worth distinguishing Esize and RM_Size values in the
+ -- dynamic case, since the RM has nothing to say about them.
-- Note that a size cannot have been given in this case, since
-- size specifications cannot be given for variable length types.
if Is_Dynamic_SO_Ref (End_Npos) then
RM_Siz := End_Npos;
- -- Set the Object_Size allowing for alignment. In the
- -- dynamic case, we have to actually do the runtime
- -- computation. We can skip this in the non-packed
- -- record case if the last component has a smaller
- -- alignment than the overall record alignment.
+ -- Set the Object_Size allowing for the alignment. In the
+ -- dynamic case, we must do the actual runtime computation.
+ -- We can skip this in the non-packed record case if the
+ -- last component has a smaller alignment than the overall
+ -- record alignment.
if Is_Dynamic_SO_Ref (End_NPMax) then
Esiz := End_NPMax;
if Is_Packed (E)
- or else Alignment (Prev_Comp) < Align
+ or else Alignment (Etype (Prev_Comp)) < Align
then
- -- The expression we build is
- -- (expr + align - 1) / align * align
+ -- The expression we build is:
+ -- (expr + align - 1) / align * align
Esiz :=
SO_Ref_From_Expr
-- accordingly. We also adjust the size to match the
-- alignment here.
- Esiz := (End_NPMax + Align - 1) / Align * Align * SSU;
+ Esiz := (End_NPMax + Align - 1) / Align * Align * SSU;
-- Compute the resulting Value_Size (RM_Size). For this
-- purpose we do not force alignment of the record or
procedure Layout_Non_Variant_Record is
Esiz : SO_Ref;
RM_Siz : SO_Ref;
-
begin
Layout_Components (First_Entity (E), Last_Entity (E), Esiz, RM_Siz);
Set_Esize (E, Esiz);
---------------------------
procedure Layout_Variant_Record is
- Tdef : constant Node_Id := Type_Definition (Decl);
- Dlist : constant List_Id := Discriminant_Specifications (Decl);
- Esiz : SO_Ref;
+ Tdef : constant Node_Id := Type_Definition (Decl);
+ First_Discr : Entity_Id;
+ Last_Discr : Entity_Id;
+ Esiz : SO_Ref;
+
RM_Siz : SO_Ref;
+ pragma Warnings (Off, SO_Ref);
RM_Siz_Expr : Node_Id := Empty;
-- Expression for the evolving RM_Siz value. This is typically a
- -- conditional expression which involves tests of discriminant
- -- values that are formed as references to the entity V. At
- -- the end of scanning all the components, a suitable function
- -- is constructed in which V is the parameter.
+ -- conditional expression which involves tests of discriminant values
+ -- that are formed as references to the entity V. At the end of
+ -- scanning all the components, a suitable function is constructed
+ -- in which V is the parameter.
-----------------------
-- Local Subprograms --
(Clist : Node_Id;
Esiz : out SO_Ref;
RM_Siz_Expr : out Node_Id);
- -- Recursive procedure, called to layout one component list
- -- Esiz and RM_Siz_Expr are set to the Object_Size and Value_Size
- -- values respectively representing the record size up to and
- -- including the last component in the component list (including
- -- any variants in this component list). RM_Siz_Expr is returned
- -- as an expression which may in the general case involve some
- -- references to the discriminants of the current record value,
- -- referenced by selecting from the entity V.
+ -- Recursive procedure, called to lay out one component list Esiz
+ -- and RM_Siz_Expr are set to the Object_Size and Value_Size values
+ -- respectively representing the record size up to and including the
+ -- last component in the component list (including any variants in
+ -- this component list). RM_Siz_Expr is returned as an expression
+ -- which may in the general case involve some references to the
+ -- discriminants of the current record value, referenced by selecting
+ -- from the entity V.
---------------------------
-- Layout_Component_List --
if Is_Static_SO_Ref (RM_Siz) then
RM_Siz_Expr :=
Make_Integer_Literal (Loc,
- Intval => RM_Siz);
+ Intval => RM_Siz);
else
RMS_Ent := Get_Dynamic_SO_Entity (RM_Siz);
- -- If the size is represented by a function, then we
- -- create an appropriate function call using V as
- -- the parameter to the call.
+ -- If the size is represented by a function, then we create
+ -- an appropriate function call using V as the parameter to
+ -- the call.
if Is_Discrim_SO_Function (RMS_Ent) then
RM_Siz_Expr :=
Make_Function_Call (Loc,
Name => New_Occurrence_Of (RMS_Ent, Loc),
Parameter_Associations => New_List (
- Make_Identifier (Loc, Chars => Vname)));
+ Make_Identifier (Loc, Vname)));
-- If the size is represented by a constant, then the
-- expression we want is a reference to this constant
else
declare
- EsizV : SO_Ref;
- RM_SizV : Node_Id;
- Dchoice : Node_Id;
- Discrim : Node_Id;
- Dtest : Node_Id;
+ EsizV : SO_Ref;
+ RM_SizV : Node_Id;
+ Dchoice : Node_Id;
+ Discrim : Node_Id;
+ Dtest : Node_Id;
+ D_List : List_Id;
+ D_Entity : Entity_Id;
begin
RM_Siz_Expr := Empty;
-- If either value is dynamic, then we have to generate
-- an appropriate Standard_Unsigned'Max attribute call.
+ -- If one of the values is static then it needs to be
+ -- converted from bits to storage units to be compatible
+ -- with the dynamic value.
else
+ if Is_Static_SO_Ref (Esiz) then
+ Esiz := (Esiz + SSU - 1) / SSU;
+ end if;
+
+ if Is_Static_SO_Ref (EsizV) then
+ EsizV := (EsizV + SSU - 1) / SSU;
+ end if;
+
Esiz :=
SO_Ref_From_Expr
(Make_Attribute_Reference (Loc,
-- individual variants, and xxDx are the discriminant
-- checking functions generated for the variant type.
- -- If this is the first variant, we simply set the
- -- result as the expression. Note that this takes
- -- care of the others case.
+ -- If this is the first variant, we simply set the result
+ -- as the expression. Note that this takes care of the
+ -- others case.
if No (RM_Siz_Expr) then
- RM_Siz_Expr := RM_SizV;
+ RM_Siz_Expr := Bits_To_SU (RM_SizV);
-- Otherwise construct the appropriate test
else
- -- Discriminant to be tested
-
- Discrim :=
- Make_Selected_Component (Loc,
- Prefix =>
- Make_Identifier (Loc, Chars => Vname),
- Selector_Name =>
- New_Occurrence_Of
- (Entity (Name (Vpart)), Loc));
-
-- The test to be used in general is a call to the
-- discriminant checking function. However, it is
-- definitely worth special casing the very common
if No (Next (Dchoice))
and then Nkind (Dchoice) /= N_Range
then
+ -- Discriminant to be tested
+
+ Discrim :=
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Make_Identifier (Loc, Vname),
+ Selector_Name =>
+ New_Occurrence_Of
+ (Entity (Name (Vpart)), Loc));
+
Dtest :=
Make_Op_Eq (Loc,
Left_Opnd => Discrim,
Right_Opnd => New_Copy (Dchoice));
+ -- Generate a call to the discriminant-checking
+ -- function for the variant. Note that the result
+ -- has to be complemented since the function returns
+ -- False when the passed discriminant value matches.
+
else
+ -- The checking function takes all of the type's
+ -- discriminants as parameters, so a list of all
+ -- the selected discriminants must be constructed.
+
+ D_List := New_List;
+ D_Entity := First_Discriminant (E);
+ while Present (D_Entity) loop
+ Append (
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Make_Identifier (Loc, Vname),
+ Selector_Name =>
+ New_Occurrence_Of (D_Entity, Loc)),
+ D_List);
+
+ D_Entity := Next_Discriminant (D_Entity);
+ end loop;
+
Dtest :=
- Make_Function_Call (Loc,
- Name =>
- New_Occurrence_Of
- (Dcheck_Function (Var), Loc),
- Parameter_Associations => New_List (Discrim));
+ Make_Op_Not (Loc,
+ Right_Opnd =>
+ Make_Function_Call (Loc,
+ Name =>
+ New_Occurrence_Of
+ (Dcheck_Function (Var), Loc),
+ Parameter_Associations =>
+ D_List));
end if;
RM_Siz_Expr :=
Make_Conditional_Expression (Loc,
Expressions =>
- New_List (Dtest, RM_SizV, RM_Siz_Expr));
+ New_List
+ (Dtest, Bits_To_SU (RM_SizV), RM_Siz_Expr));
end if;
Prev (Var);
Build_Discr_Checking_Funcs (Decl);
- -- Layout the discriminants
+ -- Lay out the discriminants
+
+ First_Discr := First_Discriminant (E);
+ Last_Discr := First_Discr;
+ while Present (Next_Discriminant (Last_Discr)) loop
+ Next_Discriminant (Last_Discr);
+ end loop;
Layout_Components
- (From => Defining_Identifier (First (Dlist)),
- To => Defining_Identifier (Last (Dlist)),
+ (From => First_Discr,
+ To => Last_Discr,
Esiz => Esiz,
RM_Siz => RM_Siz);
- -- Layout the main component list (this will make recursive calls
- -- to layout all component lists nested within variants).
+ -- Lay out the main component list (this will make recursive calls
+ -- to lay out all component lists nested within variants).
Layout_Component_List (Component_List (Tdef), Esiz, RM_Siz_Expr);
- Set_Esize (E, Esiz);
+ Set_Esize (E, Esiz);
-- If the RM_Size is a literal, set its value
-- components themselves are all shared.
if (Ekind (E) = E_Record_Subtype
- or else Ekind (E) = E_Class_Wide_Subtype)
+ or else
+ Ekind (E) = E_Class_Wide_Subtype)
and then Present (Cloned_Subtype (E))
then
Set_Esize (E, Esize (Cloned_Subtype (E)));
-- All other cases
else
- -- Initialize aligment conservatively to 1. This value will
- -- be increased as necessary during processing of the record.
+ -- Initialize alignment conservatively to 1. This value will be
+ -- increased as necessary during processing of the record.
if Unknown_Alignment (E) then
Set_Alignment (E, Uint_1);
end if;
- -- Initialize previous component. This is Empty unless there
- -- are components which have already been laid out by component
- -- clauses. If there are such components, we start our layout of
- -- the remaining components following the last such component
+ -- Initialize previous component. This is Empty unless there are
+ -- components which have already been laid out by component clauses.
+ -- If there are such components, we start our lay out of the
+ -- remaining components following the last such component.
Prev_Comp := Empty;
- Comp := First_Entity (E);
+ Comp := First_Component_Or_Discriminant (E);
while Present (Comp) loop
- if (Ekind (Comp) = E_Component
- or else Ekind (Comp) = E_Discriminant)
- and then Present (Component_Clause (Comp))
- then
+ if Present (Component_Clause (Comp)) then
if No (Prev_Comp)
or else
Component_Bit_Offset (Comp) >
end if;
end if;
- Next_Entity (Comp);
+ Next_Component_Or_Discriminant (Comp);
end loop;
-- We have two separate circuits, one for non-variant records and
if Nkind (Decl) = N_Full_Type_Declaration
and then Has_Discriminants (E)
and then Nkind (Type_Definition (Decl)) = N_Record_Definition
+ and then Present (Component_List (Type_Definition (Decl)))
and then
Present (Variant_Part (Component_List (Type_Definition (Decl))))
then
-----------------
procedure Layout_Type (E : Entity_Id) is
+ Desig_Type : Entity_Id;
+
begin
- -- For string literal types, for now, kill the size always, this
- -- is because gigi does not like or need the size to be set ???
+ -- For string literal types, for now, kill the size always, this is
+ -- because gigi does not like or need the size to be set ???
if Ekind (E) = E_String_Literal_Subtype then
Set_Esize (E, Uint_0);
return;
end if;
- -- For access types, set size/alignment. This is system address
- -- size, except for fat pointers (unconstrained array access types),
- -- where the size is two times the address size, to accommodate the
- -- two pointers that are required for a fat pointer (data and
- -- template). Note that E_Access_Protected_Subprogram_Type is not
- -- an access type for this purpose since it is not a pointer but is
- -- equivalent to a record. For access subtypes, copy the size from
- -- the base type since Gigi represents them the same way.
+ -- For access types, set size/alignment. This is system address size,
+ -- except for fat pointers (unconstrained array access types), where the
+ -- size is two times the address size, to accommodate the two pointers
+ -- that are required for a fat pointer (data and template). Note that
+ -- E_Access_Protected_Subprogram_Type is not an access type for this
+ -- purpose since it is not a pointer but is equivalent to a record. For
+ -- access subtypes, copy the size from the base type since Gigi
+ -- represents them the same way.
if Is_Access_Type (E) then
- -- If Esize already set (e.g. by a size clause), then nothing
- -- further to be done here.
+ Desig_Type := Underlying_Type (Designated_Type (E));
+
+ -- If we only have a limited view of the type, see whether the
+ -- non-limited view is available.
+
+ if From_With_Type (Designated_Type (E))
+ and then Ekind (Designated_Type (E)) = E_Incomplete_Type
+ and then Present (Non_Limited_View (Designated_Type (E)))
+ then
+ Desig_Type := Non_Limited_View (Designated_Type (E));
+ end if;
+
+ -- If Esize already set (e.g. by a size clause), then nothing further
+ -- to be done here.
if Known_Esize (E) then
null;
- -- Access to subprogram is a strange beast, and we let the
- -- backend figure out what is needed (it may be some kind
- -- of fat pointer, including the static link for example.
+ -- Access to subprogram is a strange beast, and we let the backend
+ -- figure out what is needed (it may be some kind of fat pointer,
+ -- including the static link for example.
- elsif Ekind (E) = E_Access_Protected_Subprogram_Type then
+ elsif Is_Access_Protected_Subprogram_Type (E) then
null;
-- For access subtypes, copy the size information from base type
Set_Size_Info (E, Base_Type (E));
Set_RM_Size (E, RM_Size (Base_Type (E)));
- -- For other access types, we use either address size, or, if
- -- a fat pointer is used (pointer-to-unconstrained array case),
- -- twice the address size to accommodate a fat pointer.
+ -- For other access types, we use either address size, or, if a fat
+ -- pointer is used (pointer-to-unconstrained array case), twice the
+ -- address size to accommodate a fat pointer.
- else
- declare
- Desig : Entity_Id := Designated_Type (E);
+ elsif Present (Desig_Type)
+ and then Is_Array_Type (Desig_Type)
+ and then not Is_Constrained (Desig_Type)
+ and then not Has_Completion_In_Body (Desig_Type)
+ and then not Debug_Flag_6
+ then
+ Init_Size (E, 2 * System_Address_Size);
- begin
- if Is_Private_Type (Desig)
- and then Present (Full_View (Desig))
- then
- Desig := Full_View (Desig);
- end if;
+ -- Check for bad convention set
- if (Is_Array_Type (Desig)
- and then not Is_Constrained (Desig)
- and then not Has_Completion_In_Body (Desig)
- and then not Debug_Flag_6)
- then
- Init_Size (E, 2 * System_Address_Size);
+ if Warn_On_Export_Import
+ and then
+ (Convention (E) = Convention_C
+ or else
+ Convention (E) = Convention_CPP)
+ then
+ Error_Msg_N
+ ("?this access type does not correspond to C pointer", E);
+ end if;
- -- Check for bad convention set
+ -- If the designated type is a limited view it is unanalyzed. We can
+ -- examine the declaration itself to determine whether it will need a
+ -- fat pointer.
- if Convention (E) = Convention_C
- or else
- Convention (E) = Convention_CPP
- then
- Error_Msg_N
- ("?this access type does not " &
- "correspond to C pointer", E);
- end if;
+ elsif Present (Desig_Type)
+ and then Present (Parent (Desig_Type))
+ and then Nkind (Parent (Desig_Type)) = N_Full_Type_Declaration
+ and then
+ Nkind (Type_Definition (Parent (Desig_Type)))
+ = N_Unconstrained_Array_Definition
+ then
+ Init_Size (E, 2 * System_Address_Size);
- else
- Init_Size (E, System_Address_Size);
- end if;
- end;
+ -- When the target is AAMP, access-to-subprogram types are fat
+ -- pointers consisting of the subprogram address and a static link
+ -- (with the exception of library-level access types, where a simple
+ -- subprogram address is used).
+
+ elsif AAMP_On_Target
+ and then
+ (Ekind (E) = E_Anonymous_Access_Subprogram_Type
+ or else (Ekind (E) = E_Access_Subprogram_Type
+ and then Present (Enclosing_Subprogram (E))))
+ then
+ Init_Size (E, 2 * System_Address_Size);
+
+ else
+ Init_Size (E, System_Address_Size);
+ end if;
+
+ -- On VMS, reset size to 32 for convention C access type if no
+ -- explicit size clause is given and the default size is 64. Really
+ -- we do not know the size, since depending on options for the VMS
+ -- compiler, the size of a pointer type can be 32 or 64, but choosing
+ -- 32 as the default improves compatibility with legacy VMS code.
+
+ -- Note: we do not use Has_Size_Clause in the test below, because we
+ -- want to catch the case of a derived type inheriting a size clause.
+ -- We want to consider this to be an explicit size clause for this
+ -- purpose, since it would be weird not to inherit the size in this
+ -- case.
+
+ -- We do NOT do this if we are in -gnatdm mode on a non-VMS target
+ -- since in that case we want the normal pointer representation.
+
+ if Opt.True_VMS_Target
+ and then (Convention (E) = Convention_C
+ or else
+ Convention (E) = Convention_CPP)
+ and then No (Get_Attribute_Definition_Clause (E, Attribute_Size))
+ and then Esize (E) = 64
+ then
+ Init_Size (E, 32);
end if;
- Set_Prim_Alignment (E);
+ Set_Elem_Alignment (E);
-- Scalar types: set size and alignment
elsif Is_Scalar_Type (E) then
- -- For discrete types, the RM_Size and Esize must be set
- -- already, since this is part of the earlier processing
- -- and the front end is always required to layout the
- -- sizes of such types (since they are available as static
- -- attributes). All we do is to check that this rule is
- -- indeed obeyed!
+ -- For discrete types, the RM_Size and Esize must be set already,
+ -- since this is part of the earlier processing and the front end is
+ -- always required to lay out the sizes of such types (since they are
+ -- available as static attributes). All we do is to check that this
+ -- rule is indeed obeyed!
if Is_Discrete_Type (E) then
- -- If the RM_Size is not set, then here is where we set it.
+ -- If the RM_Size is not set, then here is where we set it
-- Note: an RM_Size of zero looks like not set here, but this
-- is a rare case, and we can simply reset it without any harm.
Init_Esize (E, S);
exit;
- -- If the RM_Size is greater than 64 (happens only
- -- when strange values are specified by the user,
- -- then Esize is simply a copy of RM_Size, it will
- -- be further refined later on)
+ -- If the RM_Size is greater than 64 (happens only when
+ -- strange values are specified by the user, then Esize
+ -- is simply a copy of RM_Size, it will be further
+ -- refined later on)
elsif S = 64 then
Set_Esize (E, RM_Size (E));
end;
end if;
- -- For non-discrete sclar types, if the RM_Size is not set,
- -- then set it now to a copy of the Esize if the Esize is set.
+ -- For non-discrete scalar types, if the RM_Size is not set, then set
+ -- it now to a copy of the Esize if the Esize is set.
else
if Known_Esize (E) and then Unknown_RM_Size (E) then
end if;
end if;
- Set_Prim_Alignment (E);
+ Set_Elem_Alignment (E);
- -- Non-primitive types
+ -- Non-elementary (composite) types
else
- -- If RM_Size is known, set Esize if not known
+ -- For packed arrays, take size and alignment values from the packed
+ -- array type if a packed array type has been created and the fields
+ -- are not currently set.
- if Known_RM_Size (E) and then Unknown_Esize (E) then
+ if Is_Array_Type (E) and then Present (Packed_Array_Type (E)) then
+ declare
+ PAT : constant Entity_Id := Packed_Array_Type (E);
- -- If the alignment is known, we bump the Esize up to the
- -- next alignment boundary if it is not already on one.
+ begin
+ if Unknown_Esize (E) then
+ Set_Esize (E, Esize (PAT));
+ end if;
- if Known_Alignment (E) then
- declare
- A : constant Uint := Alignment_In_Bits (E);
- S : constant SO_Ref := RM_Size (E);
+ if Unknown_RM_Size (E) then
+ Set_RM_Size (E, RM_Size (PAT));
+ end if;
- begin
- Set_Esize (E, (S * A + A - 1) / A);
- end;
- end if;
+ if Unknown_Alignment (E) then
+ Set_Alignment (E, Alignment (PAT));
+ end if;
+ end;
+ end if;
- -- If Esize is set, and RM_Size is not, RM_Size is copied from
- -- Esize at least for now this seems reasonable, and is in any
- -- case needed for compatibility with old versions of gigi.
- -- look to be unknown.
+ -- If Esize is set, and RM_Size is not, RM_Size is copied from Esize.
+ -- At least for now this seems reasonable, and is in any case needed
+ -- for compatibility with old versions of gigi.
- elsif Known_Esize (E) and then Unknown_RM_Size (E) then
+ if Known_Esize (E) and then Unknown_RM_Size (E) then
Set_RM_Size (E, Esize (E));
end if;
- -- For array base types, set component size if object size of
- -- the component type is known and is a small power of 2 (8,
- -- 16, 32, 64), since this is what will always be used.
+ -- For array base types, set component size if object size of the
+ -- component type is known and is a small power of 2 (8, 16, 32, 64),
+ -- since this is what will always be used.
if Ekind (E) = E_Array_Type
and then Unknown_Component_Size (E)
CT : constant Entity_Id := Component_Type (E);
begin
- -- For some reasons, access types can cause trouble,
- -- So let's just do this for discrete types ???
+ -- For some reasons, access types can cause trouble, So let's
+ -- just do this for scalar types ???
if Present (CT)
- and then Is_Discrete_Type (CT)
+ and then Is_Scalar_Type (CT)
and then Known_Static_Esize (CT)
then
declare
S : constant Uint := Esize (CT);
-
begin
- if S = 8 or else
- S = 16 or else
- S = 32 or else
- S = 64
- then
- Set_Component_Size (E, Esize (CT));
+ if Addressable (S) then
+ Set_Component_Size (E, S);
end if;
end;
end if;
end if;
end if;
- -- Layout array and record types if front end layout set
+ -- Lay out array and record types if front end layout set
if Frontend_Layout_On_Target then
if Is_Array_Type (E) and then not Is_Bit_Packed_Array (E) then
elsif Is_Record_Type (E) then
Layout_Record_Type (E);
end if;
+
+ -- Case of backend layout, we still do a little in the front end
+
+ else
+ -- Processing for record types
+
+ if Is_Record_Type (E) then
+
+ -- Special remaining processing for record types with a known
+ -- size of 16, 32, or 64 bits whose alignment is not yet set.
+ -- For these types, we set a corresponding alignment matching
+ -- the size if possible, or as large as possible if not.
+
+ if Convention (E) = Convention_Ada
+ and then not Debug_Flag_Q
+ then
+ Set_Composite_Alignment (E);
+ end if;
+
+ -- Processing for array types
+
+ elsif Is_Array_Type (E) then
+
+ -- For arrays that are required to be atomic, we do the same
+ -- processing as described above for short records, since we
+ -- really need to have the alignment set for the whole array.
+
+ if Is_Atomic (E) and then not Debug_Flag_Q then
+ Set_Composite_Alignment (E);
+ end if;
+
+ -- For unpacked array types, set an alignment of 1 if we know
+ -- that the component alignment is not greater than 1. The reason
+ -- we do this is to avoid unnecessary copying of slices of such
+ -- arrays when passed to subprogram parameters (see special test
+ -- in Exp_Ch6.Expand_Actuals).
+
+ if not Is_Packed (E)
+ and then Unknown_Alignment (E)
+ then
+ if Known_Static_Component_Size (E)
+ and then Component_Size (E) = 1
+ then
+ Set_Alignment (E, Uint_1);
+ end if;
+ end if;
+
+ -- We need to know whether the size depends on the value of one
+ -- or more discriminants to select the return mechanism. Skip if
+ -- errors are present, to prevent cascaded messages.
+
+ if Serious_Errors_Detected = 0 then
+ Compute_Size_Depends_On_Discriminant (E);
+ end if;
+
+ end if;
+ end if;
+
+ -- Final step is to check that Esize and RM_Size are compatible
+
+ if Known_Static_Esize (E) and then Known_Static_RM_Size (E) then
+ if Esize (E) < RM_Size (E) then
+
+ -- Esize is less than RM_Size. That's not good. First we test
+ -- whether this was set deliberately with an Object_Size clause
+ -- and if so, object to the clause.
+
+ if Has_Object_Size_Clause (E) then
+ Error_Msg_Uint_1 := RM_Size (E);
+ Error_Msg_F
+ ("object size is too small, minimum allowed is ^",
+ Expression (Get_Attribute_Definition_Clause
+ (E, Attribute_Object_Size)));
+ end if;
+
+ -- Adjust Esize up to RM_Size value
+
+ declare
+ Size : constant Uint := RM_Size (E);
+
+ begin
+ Set_Esize (E, RM_Size (E));
+
+ -- For scalar types, increase Object_Size to power of 2, but
+ -- not less than a storage unit in any case (i.e., normally
+ -- this means it will be storage-unit addressable).
+
+ if Is_Scalar_Type (E) then
+ if Size <= System_Storage_Unit then
+ Init_Esize (E, System_Storage_Unit);
+ elsif Size <= 16 then
+ Init_Esize (E, 16);
+ elsif Size <= 32 then
+ Init_Esize (E, 32);
+ else
+ Set_Esize (E, (Size + 63) / 64 * 64);
+ end if;
+
+ -- Finally, make sure that alignment is consistent with
+ -- the newly assigned size.
+
+ while Alignment (E) * System_Storage_Unit < Esize (E)
+ and then Alignment (E) < Maximum_Alignment
+ loop
+ Set_Alignment (E, 2 * Alignment (E));
+ end loop;
+ end if;
+ end;
+ end if;
end if;
end Layout_Type;
procedure Rewrite_Integer (N : Node_Id; V : Uint) is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
-
begin
Rewrite (N, Make_Integer_Literal (Loc, Intval => V));
Set_Etype (N, Typ);
SC : Node_Id;
procedure Check_Size_Too_Small (Spec : Uint; Min : Uint);
- -- Spec is the number of bit specified in the size clause, and
- -- Min is the minimum computed size. An error is given that the
- -- specified size is too small if Spec < Min, and in this case
- -- both Esize and RM_Size are set to unknown in E. The error
- -- message is posted on node SC.
+ -- Spec is the number of bit specified in the size clause, and Min is
+ -- the minimum computed size. An error is given that the specified size
+ -- is too small if Spec < Min, and in this case both Esize and RM_Size
+ -- are set to unknown in E. The error message is posted on node SC.
procedure Check_Unused_Bits (Spec : Uint; Max : Uint);
- -- Spec is the number of bits specified in the size clause, and
- -- Max is the maximum computed size. A warning is given about
- -- unused bits if Spec > Max. This warning is posted on node SC.
+ -- Spec is the number of bits specified in the size clause, and Max is
+ -- the maximum computed size. A warning is given about unused bits if
+ -- Spec > Max. This warning is posted on node SC.
--------------------------
-- Check_Size_Too_Small --
begin
if Spec < Min then
Error_Msg_Uint_1 := Min;
- Error_Msg_NE
- ("size for & too small, minimum allowed is ^", SC, E);
+ Error_Msg_NE ("size for & too small, minimum allowed is ^", SC, E);
Init_Esize (E);
Init_RM_Size (E);
end if;
end if;
end if;
- -- Case where Value_Size (RM_Size) is set by specific Value_Size
- -- clause (we do not need to worry about Value_Size being set by
- -- a Size clause, since that will have set Esize as well, and we
- -- already took care of that case).
+ -- Case where Value_Size (RM_Size) is set by specific Value_Size clause
+ -- (we do not need to worry about Value_Size being set by a Size clause,
+ -- since that will have set Esize as well, and we already took care of
+ -- that case).
if Known_Static_RM_Size (E) then
SC := Get_Attribute_Definition_Clause (E, Attribute_Value_Size);
end if;
end Set_And_Check_Static_Size;
+ -----------------------------
+ -- Set_Composite_Alignment --
+ -----------------------------
+
+ procedure Set_Composite_Alignment (E : Entity_Id) is
+ Siz : Uint;
+ Align : Nat;
+
+ begin
+ -- If alignment is already set, then nothing to do
+
+ if Known_Alignment (E) then
+ return;
+ end if;
+
+ -- Alignment is not known, see if we can set it, taking into account
+ -- the setting of the Optimize_Alignment mode.
+
+ -- If Optimize_Alignment is set to Space, then packed records always
+ -- have an alignment of 1. But don't do anything for atomic records
+ -- since we may need higher alignment for indivisible access.
+
+ if Optimize_Alignment_Space (E)
+ and then Is_Record_Type (E)
+ and then Is_Packed (E)
+ and then not Is_Atomic (E)
+ then
+ Align := 1;
+
+ -- Not a record, or not packed
+
+ else
+ -- The only other cases we worry about here are where the size is
+ -- statically known at compile time.
+
+ if Known_Static_Esize (E) then
+ Siz := Esize (E);
+
+ elsif Unknown_Esize (E)
+ and then Known_Static_RM_Size (E)
+ then
+ Siz := RM_Size (E);
+
+ else
+ return;
+ end if;
+
+ -- Size is known, alignment is not set
+
+ -- Reset alignment to match size if the known size is exactly 2, 4,
+ -- or 8 storage units.
+
+ if Siz = 2 * System_Storage_Unit then
+ Align := 2;
+ elsif Siz = 4 * System_Storage_Unit then
+ Align := 4;
+ elsif Siz = 8 * System_Storage_Unit then
+ Align := 8;
+
+ -- If Optimize_Alignment is set to Space, then make sure the
+ -- alignment matches the size, for example, if the size is 17
+ -- bytes then we want an alignment of 1 for the type.
+
+ elsif Optimize_Alignment_Space (E) then
+ if Siz mod (8 * System_Storage_Unit) = 0 then
+ Align := 8;
+ elsif Siz mod (4 * System_Storage_Unit) = 0 then
+ Align := 4;
+ elsif Siz mod (2 * System_Storage_Unit) = 0 then
+ Align := 2;
+ else
+ Align := 1;
+ end if;
+
+ -- If Optimize_Alignment is set to Time, then we reset for odd
+ -- "in between sizes", for example a 17 bit record is given an
+ -- alignment of 4. Note that this matches the old VMS behavior
+ -- in versions of GNAT prior to 6.1.1.
+
+ elsif Optimize_Alignment_Time (E)
+ and then Siz > System_Storage_Unit
+ and then Siz <= 8 * System_Storage_Unit
+ then
+ if Siz <= 2 * System_Storage_Unit then
+ Align := 2;
+ elsif Siz <= 4 * System_Storage_Unit then
+ Align := 4;
+ else -- Siz <= 8 * System_Storage_Unit then
+ Align := 8;
+ end if;
+
+ -- No special alignment fiddling needed
+
+ else
+ return;
+ end if;
+ end if;
+
+ -- Here we have Set Align to the proposed improved value. Make sure the
+ -- value set does not exceed Maximum_Alignment for the target.
+
+ if Align > Maximum_Alignment then
+ Align := Maximum_Alignment;
+ end if;
+
+ -- Further processing for record types only to reduce the alignment
+ -- set by the above processing in some specific cases. We do not
+ -- do this for atomic records, since we need max alignment there,
+
+ if Is_Record_Type (E) and then not Is_Atomic (E) then
+
+ -- For records, there is generally no point in setting alignment
+ -- higher than word size since we cannot do better than move by
+ -- words in any case. Omit this if we are optimizing for time,
+ -- since conceivably we may be able to do better.
+
+ if Align > System_Word_Size / System_Storage_Unit
+ and then not Optimize_Alignment_Time (E)
+ then
+ Align := System_Word_Size / System_Storage_Unit;
+ end if;
+
+ -- Check components. If any component requires a higher alignment,
+ -- then we set that higher alignment in any case. Don't do this if
+ -- we have Optimize_Alignment set to Space. Note that that covers
+ -- the case of packed records, where we already set alignment to 1.
+
+ if not Optimize_Alignment_Space (E) then
+ declare
+ Comp : Entity_Id;
+
+ begin
+ Comp := First_Component (E);
+ while Present (Comp) loop
+ if Known_Alignment (Etype (Comp)) then
+ declare
+ Calign : constant Uint := Alignment (Etype (Comp));
+
+ begin
+ -- The cases to process are when the alignment of the
+ -- component type is larger than the alignment we have
+ -- so far, and either there is no component clause for
+ -- the component, or the length set by the component
+ -- clause matches the length of the component type.
+
+ if Calign > Align
+ and then
+ (Unknown_Esize (Comp)
+ or else (Known_Static_Esize (Comp)
+ and then
+ Esize (Comp) =
+ Calign * System_Storage_Unit))
+ then
+ Align := UI_To_Int (Calign);
+ end if;
+ end;
+ end if;
+
+ Next_Component (Comp);
+ end loop;
+ end;
+ end if;
+ end if;
+
+ -- Set chosen alignment, and increase Esize if necessary to match the
+ -- chosen alignment.
+
+ Set_Alignment (E, UI_From_Int (Align));
+
+ if Known_Static_Esize (E)
+ and then Esize (E) < Align * System_Storage_Unit
+ then
+ Set_Esize (E, UI_From_Int (Align * System_Storage_Unit));
+ end if;
+ end Set_Composite_Alignment;
+
--------------------------
-- Set_Discrete_RM_Size --
--------------------------
FST : constant Entity_Id := First_Subtype (Def_Id);
begin
- -- All discrete types except for the base types in standard
- -- are constrained, so indicate this by setting Is_Constrained.
+ -- All discrete types except for the base types in standard are
+ -- constrained, so indicate this by setting Is_Constrained.
Set_Is_Constrained (Def_Id);
- -- We set generic types to have an unknown size, since the
- -- representation of a generic type is irrelevant, in view
- -- of the fact that they have nothing to do with code.
+ -- Set generic types to have an unknown size, since the representation
+ -- of a generic type is irrelevant, in view of the fact that they have
+ -- nothing to do with code.
if Is_Generic_Type (Root_Type (FST)) then
Set_RM_Size (Def_Id, Uint_0);
- -- If the subtype statically matches the first subtype, then
- -- it is required to have exactly the same layout. This is
- -- required by aliasing considerations.
+ -- If the subtype statically matches the first subtype, then it is
+ -- required to have exactly the same layout. This is required by
+ -- aliasing considerations.
elsif Def_Id /= FST and then
Subtypes_Statically_Match (Def_Id, FST)
Set_RM_Size (Def_Id, RM_Size (FST));
Set_Size_Info (Def_Id, FST);
- -- In all other cases the RM_Size is set to the minimum size.
- -- Note that this routine is never called for subtypes for which
- -- the RM_Size is set explicitly by an attribute clause.
+ -- In all other cases the RM_Size is set to the minimum size. Note that
+ -- this routine is never called for subtypes for which the RM_Size is
+ -- set explicitly by an attribute clause.
else
Set_RM_Size (Def_Id, UI_From_Int (Minimum_Size (Def_Id)));
end Set_Discrete_RM_Size;
------------------------
- -- Set_Prim_Alignment --
+ -- Set_Elem_Alignment --
------------------------
- procedure Set_Prim_Alignment (E : Entity_Id) is
+ procedure Set_Elem_Alignment (E : Entity_Id) is
begin
-- Do not set alignment for packed array types, unless we are doing
-- front end layout, because otherwise this is always handled in the
return;
-- If the size is not set, then don't attempt to set the alignment. This
- -- happens in the backend layout case for access to subprogram types.
+ -- happens in the backend layout case for access-to-subprogram types.
elsif not Known_Static_Esize (E) then
return;
return;
end if;
- -- Here we calculate the alignment as the largest power of two
- -- multiple of System.Storage_Unit that does not exceed either
- -- the actual size of the type, or the maximum allowed alignment.
+ -- Here we calculate the alignment as the largest power of two multiple
+ -- of System.Storage_Unit that does not exceed either the object size of
+ -- the type, or the maximum allowed alignment.
declare
- S : constant Int :=
- UI_To_Int (Esize (E)) / SSU;
- A : Nat;
+ S : constant Int := UI_To_Int (Esize (E)) / SSU;
+ A : Nat;
+ Max_Alignment : Nat;
begin
+ -- If the default alignment of "double" floating-point types is
+ -- specifically capped, enforce the cap.
+
+ if Ttypes.Target_Double_Float_Alignment > 0
+ and then S = 8
+ and then Is_Floating_Point_Type (E)
+ then
+ Max_Alignment := Ttypes.Target_Double_Float_Alignment;
+
+ -- If the default alignment of "double" or larger scalar types is
+ -- specifically capped, enforce the cap.
+
+ elsif Ttypes.Target_Double_Scalar_Alignment > 0
+ and then S >= 8
+ and then Is_Scalar_Type (E)
+ then
+ Max_Alignment := Ttypes.Target_Double_Scalar_Alignment;
+
+ -- Otherwise enforce the overall alignment cap
+
+ else
+ Max_Alignment := Ttypes.Maximum_Alignment;
+ end if;
+
A := 1;
- while 2 * A <= Ttypes.Maximum_Alignment
- and then 2 * A <= S
- loop
+ while 2 * A <= Max_Alignment and then 2 * A <= S loop
A := 2 * A;
end loop;
- -- Now we think we should set the alignment to A, but we
- -- skip this if an alignment is already set to a value
- -- greater than A (happens for derived types).
+ -- If alignment is currently not set, then we can safetly set it to
+ -- this new calculated value.
- -- However, if the alignment is known and too small it
- -- must be increased, this happens in a case like:
+ if Unknown_Alignment (E) then
+ Init_Alignment (E, A);
- -- type R is new Character;
- -- for R'Size use 16;
+ -- Cases where we have inherited an alignment
- -- Here the alignment inherited from Character is 1, but
- -- it must be increased to 2 to reflect the increased size.
+ -- For constructed types, always reset the alignment, these are
+ -- Generally invisible to the user anyway, and that way we are
+ -- sure that no constructed types have weird alignments.
- if Unknown_Alignment (E) or else Alignment (E) < A then
+ elsif not Comes_From_Source (E) then
Init_Alignment (E, A);
+
+ -- If this inherited alignment is the same as the one we computed,
+ -- then obviously everything is fine, and we do not need to reset it.
+
+ elsif Alignment (E) = A then
+ null;
+
+ -- Now we come to the difficult cases where we have inherited an
+ -- alignment and size, but overridden the size but not the alignment.
+
+ elsif Has_Size_Clause (E) or else Has_Object_Size_Clause (E) then
+
+ -- This is tricky, it might be thought that we should try to
+ -- inherit the alignment, since that's what the RM implies, but
+ -- that leads to complex rules and oddities. Consider for example:
+
+ -- type R is new Character;
+ -- for R'Size use 16;
+
+ -- It seems quite bogus in this case to inherit an alignment of 1
+ -- from the parent type Character. Furthermore, if that's what the
+ -- programmer really wanted for some odd reason, then they could
+ -- specify the alignment they wanted.
+
+ -- Furthermore we really don't want to inherit the alignment in
+ -- the case of a specified Object_Size for a subtype, since then
+ -- there would be no way of overriding to give a reasonable value
+ -- (we don't have an Object_Subtype attribute). Consider:
+
+ -- subtype R is new Character;
+ -- for R'Object_Size use 16;
+
+ -- If we inherit the alignment of 1, then we have an odd
+ -- inefficient alignment for the subtype, which cannot be fixed.
+
+ -- So we make the decision that if Size (or Object_Size) is given
+ -- (and, in the case of a first subtype, the alignment is not set
+ -- with a specific alignment clause). We reset the alignment to
+ -- the appropriate value for the specified size. This is a nice
+ -- simple rule to implement and document.
+
+ -- There is one slight glitch, which is that a confirming size
+ -- clause can now change the alignment, which, if we really think
+ -- that confirming rep clauses should have no effect, is a no-no.
+
+ -- type R is new Character;
+ -- for R'Alignment use 2;
+ -- type S is new R;
+ -- for S'Size use Character'Size;
+
+ -- Now the alignment of S is 1 instead of 2, as a result of
+ -- applying the above rule to the confirming rep clause for S. Not
+ -- clear this is worth worrying about. If we recorded whether a
+ -- size clause was confirming we could avoid this, but right now
+ -- we have no way of doing that or easily figuring it out, so we
+ -- don't bother.
+
+ -- Historical note. In versions of GNAT prior to Nov 6th, 2010, an
+ -- odd distinction was made between inherited alignments greater
+ -- than the computed alignment (where the larger alignment was
+ -- inherited) and inherited alignments smaller than the computed
+ -- alignment (where the smaller alignment was overridden). This
+ -- was a dubious fix to get around an ACATS problem which seems
+ -- to have disappeared anyway, and in any case, this peculiarity
+ -- was never documented.
+
+ Init_Alignment (E, A);
+
+ -- If no Size (or Object_Size) was specified, then we inherited the
+ -- object size, so we should inherit the alignment as well and not
+ -- modify it. This takes care of cases like:
+
+ -- type R is new Integer;
+ -- for R'Alignment use 1;
+ -- subtype S is R;
+
+ -- Here we have R has a default Object_Size of 32, and a specified
+ -- alignment of 1, and it seeems right for S to inherit both values.
+
+ else
+ null;
end if;
end;
- end Set_Prim_Alignment;
+ end Set_Elem_Alignment;
----------------------
-- SO_Ref_From_Expr --
function SO_Ref_From_Expr
(Expr : Node_Id;
Ins_Type : Entity_Id;
- Vtype : Entity_Id := Empty)
- return Dynamic_SO_Ref
+ Vtype : Entity_Id := Empty;
+ Make_Func : Boolean := False) return Dynamic_SO_Ref
is
Loc : constant Source_Ptr := Sloc (Ins_Type);
-
- K : constant Entity_Id :=
- Make_Defining_Identifier (Loc,
- Chars => New_Internal_Name ('K'));
-
+ K : constant Entity_Id := Make_Temporary (Loc, 'K');
Decl : Node_Id;
+ Vtype_Primary_View : Entity_Id;
+
function Check_Node_V_Ref (N : Node_Id) return Traverse_Result;
-- Function used to check one node for reference to V
if Has_V_Ref (Expr) = Abandon then
pragma Assert (Present (Vtype));
+
+ -- Check whether Vtype is a view of a private type and ensure that
+ -- we use the primary view of the type (which is denoted by its
+ -- Etype, whether it's the type's partial or full view entity).
+ -- This is needed to make sure that we use the same (primary) view
+ -- of the type for all V formals, whether the current view of the
+ -- type is the partial or full view, so that types will always
+ -- match on calls from one size function to another.
+
+ if Has_Private_Declaration (Vtype) then
+ Vtype_Primary_View := Etype (Vtype);
+ else
+ Vtype_Primary_View := Vtype;
+ end if;
+
Set_Is_Discrim_SO_Function (K);
Decl :=
Defining_Identifier =>
Make_Defining_Identifier (Loc, Chars => Vname),
Parameter_Type =>
- New_Occurrence_Of (Vtype, Loc))),
- Subtype_Mark =>
+ New_Occurrence_Of (Vtype_Primary_View, Loc))),
+ Result_Definition =>
New_Occurrence_Of (Standard_Unsigned, Loc)),
Declarations => Empty_List,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (
- Make_Return_Statement (Loc,
+ Make_Simple_Return_Statement (Loc,
Expression => Expr))));
- -- No reference to V, create constant
+ -- The caller requests that the expression be encapsulated in a
+ -- parameterless function.
+
+ elsif Make_Func then
+ Decl :=
+ Make_Subprogram_Body (Loc,
+
+ Specification =>
+ Make_Function_Specification (Loc,
+ Defining_Unit_Name => K,
+ Parameter_Specifications => Empty_List,
+ Result_Definition =>
+ New_Occurrence_Of (Standard_Unsigned, Loc)),
+
+ Declarations => Empty_List,
+
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => New_List (
+ Make_Simple_Return_Statement (Loc, Expression => Expr))));
+
+ -- No reference to V and function not requested, so create a constant
else
Decl :=
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