| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ P A K D -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2004 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- -- |
| -- 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. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with Atree; use Atree; |
| with Checks; use Checks; |
| with Einfo; use Einfo; |
| with Exp_Dbug; use Exp_Dbug; |
| with Exp_Util; use Exp_Util; |
| with Nlists; use Nlists; |
| with Nmake; use Nmake; |
| with Rtsfind; use Rtsfind; |
| with Sem; use Sem; |
| with Sem_Ch3; use Sem_Ch3; |
| with Sem_Ch8; use Sem_Ch8; |
| with Sem_Ch13; use Sem_Ch13; |
| 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 Ttypes; use Ttypes; |
| with Uintp; use Uintp; |
| |
| package body Exp_Pakd is |
| |
| --------------------------- |
| -- Endian Considerations -- |
| --------------------------- |
| |
| -- As described in the specification, bit numbering in a packed array |
| -- is consistent with bit numbering in a record representation clause, |
| -- and hence dependent on the endianness of the machine: |
| |
| -- For little-endian machines, element zero is at the right hand end |
| -- (low order end) of a bit field. |
| |
| -- For big-endian machines, element zero is at the left hand end |
| -- (high order end) of a bit field. |
| |
| -- The shifts that are used to right justify a field therefore differ |
| -- in the two cases. For the little-endian case, we can simply use the |
| -- bit number (i.e. the element number * element size) as the count for |
| -- a right shift. For the big-endian case, we have to subtract the shift |
| -- count from an appropriate constant to use in the right shift. We use |
| -- rotates instead of shifts (which is necessary in the store case to |
| -- preserve other fields), and we expect that the backend will be able |
| -- to change the right rotate into a left rotate, avoiding the subtract, |
| -- if the architecture provides such an instruction. |
| |
| ---------------------------------------------- |
| -- Entity Tables for Packed Access Routines -- |
| ---------------------------------------------- |
| |
| -- For the cases of component size = 3,5-7,9-15,17-31,33-63 we call |
| -- library routines. This table is used to obtain the entity for the |
| -- proper routine. |
| |
| type E_Array is array (Int range 01 .. 63) of RE_Id; |
| |
| -- Array of Bits_nn entities. Note that we do not use library routines |
| -- for the 8-bit and 16-bit cases, but we still fill in the table, using |
| -- entries from System.Unsigned, because we also use this table for |
| -- certain special unchecked conversions in the big-endian case. |
| |
| Bits_Id : constant E_Array := |
| (01 => RE_Bits_1, |
| 02 => RE_Bits_2, |
| 03 => RE_Bits_03, |
| 04 => RE_Bits_4, |
| 05 => RE_Bits_05, |
| 06 => RE_Bits_06, |
| 07 => RE_Bits_07, |
| 08 => RE_Unsigned_8, |
| 09 => RE_Bits_09, |
| 10 => RE_Bits_10, |
| 11 => RE_Bits_11, |
| 12 => RE_Bits_12, |
| 13 => RE_Bits_13, |
| 14 => RE_Bits_14, |
| 15 => RE_Bits_15, |
| 16 => RE_Unsigned_16, |
| 17 => RE_Bits_17, |
| 18 => RE_Bits_18, |
| 19 => RE_Bits_19, |
| 20 => RE_Bits_20, |
| 21 => RE_Bits_21, |
| 22 => RE_Bits_22, |
| 23 => RE_Bits_23, |
| 24 => RE_Bits_24, |
| 25 => RE_Bits_25, |
| 26 => RE_Bits_26, |
| 27 => RE_Bits_27, |
| 28 => RE_Bits_28, |
| 29 => RE_Bits_29, |
| 30 => RE_Bits_30, |
| 31 => RE_Bits_31, |
| 32 => RE_Unsigned_32, |
| 33 => RE_Bits_33, |
| 34 => RE_Bits_34, |
| 35 => RE_Bits_35, |
| 36 => RE_Bits_36, |
| 37 => RE_Bits_37, |
| 38 => RE_Bits_38, |
| 39 => RE_Bits_39, |
| 40 => RE_Bits_40, |
| 41 => RE_Bits_41, |
| 42 => RE_Bits_42, |
| 43 => RE_Bits_43, |
| 44 => RE_Bits_44, |
| 45 => RE_Bits_45, |
| 46 => RE_Bits_46, |
| 47 => RE_Bits_47, |
| 48 => RE_Bits_48, |
| 49 => RE_Bits_49, |
| 50 => RE_Bits_50, |
| 51 => RE_Bits_51, |
| 52 => RE_Bits_52, |
| 53 => RE_Bits_53, |
| 54 => RE_Bits_54, |
| 55 => RE_Bits_55, |
| 56 => RE_Bits_56, |
| 57 => RE_Bits_57, |
| 58 => RE_Bits_58, |
| 59 => RE_Bits_59, |
| 60 => RE_Bits_60, |
| 61 => RE_Bits_61, |
| 62 => RE_Bits_62, |
| 63 => RE_Bits_63); |
| |
| -- Array of Get routine entities. These are used to obtain an element |
| -- from a packed array. The N'th entry is used to obtain elements from |
| -- a packed array whose component size is N. RE_Null is used as a null |
| -- entry, for the cases where a library routine is not used. |
| |
| Get_Id : constant E_Array := |
| (01 => RE_Null, |
| 02 => RE_Null, |
| 03 => RE_Get_03, |
| 04 => RE_Null, |
| 05 => RE_Get_05, |
| 06 => RE_Get_06, |
| 07 => RE_Get_07, |
| 08 => RE_Null, |
| 09 => RE_Get_09, |
| 10 => RE_Get_10, |
| 11 => RE_Get_11, |
| 12 => RE_Get_12, |
| 13 => RE_Get_13, |
| 14 => RE_Get_14, |
| 15 => RE_Get_15, |
| 16 => RE_Null, |
| 17 => RE_Get_17, |
| 18 => RE_Get_18, |
| 19 => RE_Get_19, |
| 20 => RE_Get_20, |
| 21 => RE_Get_21, |
| 22 => RE_Get_22, |
| 23 => RE_Get_23, |
| 24 => RE_Get_24, |
| 25 => RE_Get_25, |
| 26 => RE_Get_26, |
| 27 => RE_Get_27, |
| 28 => RE_Get_28, |
| 29 => RE_Get_29, |
| 30 => RE_Get_30, |
| 31 => RE_Get_31, |
| 32 => RE_Null, |
| 33 => RE_Get_33, |
| 34 => RE_Get_34, |
| 35 => RE_Get_35, |
| 36 => RE_Get_36, |
| 37 => RE_Get_37, |
| 38 => RE_Get_38, |
| 39 => RE_Get_39, |
| 40 => RE_Get_40, |
| 41 => RE_Get_41, |
| 42 => RE_Get_42, |
| 43 => RE_Get_43, |
| 44 => RE_Get_44, |
| 45 => RE_Get_45, |
| 46 => RE_Get_46, |
| 47 => RE_Get_47, |
| 48 => RE_Get_48, |
| 49 => RE_Get_49, |
| 50 => RE_Get_50, |
| 51 => RE_Get_51, |
| 52 => RE_Get_52, |
| 53 => RE_Get_53, |
| 54 => RE_Get_54, |
| 55 => RE_Get_55, |
| 56 => RE_Get_56, |
| 57 => RE_Get_57, |
| 58 => RE_Get_58, |
| 59 => RE_Get_59, |
| 60 => RE_Get_60, |
| 61 => RE_Get_61, |
| 62 => RE_Get_62, |
| 63 => RE_Get_63); |
| |
| -- Array of Get routine entities to be used in the case where the packed |
| -- array is itself a component of a packed structure, and therefore may |
| -- not be fully aligned. This only affects the even sizes, since for the |
| -- odd sizes, we do not get any fixed alignment in any case. |
| |
| GetU_Id : constant E_Array := |
| (01 => RE_Null, |
| 02 => RE_Null, |
| 03 => RE_Get_03, |
| 04 => RE_Null, |
| 05 => RE_Get_05, |
| 06 => RE_GetU_06, |
| 07 => RE_Get_07, |
| 08 => RE_Null, |
| 09 => RE_Get_09, |
| 10 => RE_GetU_10, |
| 11 => RE_Get_11, |
| 12 => RE_GetU_12, |
| 13 => RE_Get_13, |
| 14 => RE_GetU_14, |
| 15 => RE_Get_15, |
| 16 => RE_Null, |
| 17 => RE_Get_17, |
| 18 => RE_GetU_18, |
| 19 => RE_Get_19, |
| 20 => RE_GetU_20, |
| 21 => RE_Get_21, |
| 22 => RE_GetU_22, |
| 23 => RE_Get_23, |
| 24 => RE_GetU_24, |
| 25 => RE_Get_25, |
| 26 => RE_GetU_26, |
| 27 => RE_Get_27, |
| 28 => RE_GetU_28, |
| 29 => RE_Get_29, |
| 30 => RE_GetU_30, |
| 31 => RE_Get_31, |
| 32 => RE_Null, |
| 33 => RE_Get_33, |
| 34 => RE_GetU_34, |
| 35 => RE_Get_35, |
| 36 => RE_GetU_36, |
| 37 => RE_Get_37, |
| 38 => RE_GetU_38, |
| 39 => RE_Get_39, |
| 40 => RE_GetU_40, |
| 41 => RE_Get_41, |
| 42 => RE_GetU_42, |
| 43 => RE_Get_43, |
| 44 => RE_GetU_44, |
| 45 => RE_Get_45, |
| 46 => RE_GetU_46, |
| 47 => RE_Get_47, |
| 48 => RE_GetU_48, |
| 49 => RE_Get_49, |
| 50 => RE_GetU_50, |
| 51 => RE_Get_51, |
| 52 => RE_GetU_52, |
| 53 => RE_Get_53, |
| 54 => RE_GetU_54, |
| 55 => RE_Get_55, |
| 56 => RE_GetU_56, |
| 57 => RE_Get_57, |
| 58 => RE_GetU_58, |
| 59 => RE_Get_59, |
| 60 => RE_GetU_60, |
| 61 => RE_Get_61, |
| 62 => RE_GetU_62, |
| 63 => RE_Get_63); |
| |
| -- Array of Set routine entities. These are used to assign an element |
| -- of a packed array. The N'th entry is used to assign elements for |
| -- a packed array whose component size is N. RE_Null is used as a null |
| -- entry, for the cases where a library routine is not used. |
| |
| Set_Id : constant E_Array := |
| (01 => RE_Null, |
| 02 => RE_Null, |
| 03 => RE_Set_03, |
| 04 => RE_Null, |
| 05 => RE_Set_05, |
| 06 => RE_Set_06, |
| 07 => RE_Set_07, |
| 08 => RE_Null, |
| 09 => RE_Set_09, |
| 10 => RE_Set_10, |
| 11 => RE_Set_11, |
| 12 => RE_Set_12, |
| 13 => RE_Set_13, |
| 14 => RE_Set_14, |
| 15 => RE_Set_15, |
| 16 => RE_Null, |
| 17 => RE_Set_17, |
| 18 => RE_Set_18, |
| 19 => RE_Set_19, |
| 20 => RE_Set_20, |
| 21 => RE_Set_21, |
| 22 => RE_Set_22, |
| 23 => RE_Set_23, |
| 24 => RE_Set_24, |
| 25 => RE_Set_25, |
| 26 => RE_Set_26, |
| 27 => RE_Set_27, |
| 28 => RE_Set_28, |
| 29 => RE_Set_29, |
| 30 => RE_Set_30, |
| 31 => RE_Set_31, |
| 32 => RE_Null, |
| 33 => RE_Set_33, |
| 34 => RE_Set_34, |
| 35 => RE_Set_35, |
| 36 => RE_Set_36, |
| 37 => RE_Set_37, |
| 38 => RE_Set_38, |
| 39 => RE_Set_39, |
| 40 => RE_Set_40, |
| 41 => RE_Set_41, |
| 42 => RE_Set_42, |
| 43 => RE_Set_43, |
| 44 => RE_Set_44, |
| 45 => RE_Set_45, |
| 46 => RE_Set_46, |
| 47 => RE_Set_47, |
| 48 => RE_Set_48, |
| 49 => RE_Set_49, |
| 50 => RE_Set_50, |
| 51 => RE_Set_51, |
| 52 => RE_Set_52, |
| 53 => RE_Set_53, |
| 54 => RE_Set_54, |
| 55 => RE_Set_55, |
| 56 => RE_Set_56, |
| 57 => RE_Set_57, |
| 58 => RE_Set_58, |
| 59 => RE_Set_59, |
| 60 => RE_Set_60, |
| 61 => RE_Set_61, |
| 62 => RE_Set_62, |
| 63 => RE_Set_63); |
| |
| -- Array of Set routine entities to be used in the case where the packed |
| -- array is itself a component of a packed structure, and therefore may |
| -- not be fully aligned. This only affects the even sizes, since for the |
| -- odd sizes, we do not get any fixed alignment in any case. |
| |
| SetU_Id : constant E_Array := |
| (01 => RE_Null, |
| 02 => RE_Null, |
| 03 => RE_Set_03, |
| 04 => RE_Null, |
| 05 => RE_Set_05, |
| 06 => RE_SetU_06, |
| 07 => RE_Set_07, |
| 08 => RE_Null, |
| 09 => RE_Set_09, |
| 10 => RE_SetU_10, |
| 11 => RE_Set_11, |
| 12 => RE_SetU_12, |
| 13 => RE_Set_13, |
| 14 => RE_SetU_14, |
| 15 => RE_Set_15, |
| 16 => RE_Null, |
| 17 => RE_Set_17, |
| 18 => RE_SetU_18, |
| 19 => RE_Set_19, |
| 20 => RE_SetU_20, |
| 21 => RE_Set_21, |
| 22 => RE_SetU_22, |
| 23 => RE_Set_23, |
| 24 => RE_SetU_24, |
| 25 => RE_Set_25, |
| 26 => RE_SetU_26, |
| 27 => RE_Set_27, |
| 28 => RE_SetU_28, |
| 29 => RE_Set_29, |
| 30 => RE_SetU_30, |
| 31 => RE_Set_31, |
| 32 => RE_Null, |
| 33 => RE_Set_33, |
| 34 => RE_SetU_34, |
| 35 => RE_Set_35, |
| 36 => RE_SetU_36, |
| 37 => RE_Set_37, |
| 38 => RE_SetU_38, |
| 39 => RE_Set_39, |
| 40 => RE_SetU_40, |
| 41 => RE_Set_41, |
| 42 => RE_SetU_42, |
| 43 => RE_Set_43, |
| 44 => RE_SetU_44, |
| 45 => RE_Set_45, |
| 46 => RE_SetU_46, |
| 47 => RE_Set_47, |
| 48 => RE_SetU_48, |
| 49 => RE_Set_49, |
| 50 => RE_SetU_50, |
| 51 => RE_Set_51, |
| 52 => RE_SetU_52, |
| 53 => RE_Set_53, |
| 54 => RE_SetU_54, |
| 55 => RE_Set_55, |
| 56 => RE_SetU_56, |
| 57 => RE_Set_57, |
| 58 => RE_SetU_58, |
| 59 => RE_Set_59, |
| 60 => RE_SetU_60, |
| 61 => RE_Set_61, |
| 62 => RE_SetU_62, |
| 63 => RE_Set_63); |
| |
| ----------------------- |
| -- Local Subprograms -- |
| ----------------------- |
| |
| procedure Compute_Linear_Subscript |
| (Atyp : Entity_Id; |
| N : Node_Id; |
| Subscr : out Node_Id); |
| -- Given a constrained array type Atyp, and an indexed component node |
| -- N referencing an array object of this type, build an expression of |
| -- type Standard.Integer representing the zero-based linear subscript |
| -- value. This expression includes any required range checks. |
| |
| procedure Convert_To_PAT_Type (Aexp : Node_Id); |
| -- Given an expression of a packed array type, builds a corresponding |
| -- expression whose type is the implementation type used to represent |
| -- the packed array. Aexp is analyzed and resolved on entry and on exit. |
| |
| function Known_Aligned_Enough (Obj : Node_Id; Csiz : Nat) return Boolean; |
| -- There are two versions of the Set routines, the ones used when the |
| -- object is known to be sufficiently well aligned given the number of |
| -- bits, and the ones used when the object is not known to be aligned. |
| -- This routine is used to determine which set to use. Obj is a reference |
| -- to the object, and Csiz is the component size of the packed array. |
| -- True is returned if the alignment of object is known to be sufficient, |
| -- defined as 1 for odd bit sizes, 4 for bit sizes divisible by 4, and |
| -- 2 otherwise. |
| |
| function Make_Shift_Left (N : Node_Id; S : Node_Id) return Node_Id; |
| -- Build a left shift node, checking for the case of a shift count of zero |
| |
| function Make_Shift_Right (N : Node_Id; S : Node_Id) return Node_Id; |
| -- Build a right shift node, checking for the case of a shift count of zero |
| |
| function RJ_Unchecked_Convert_To |
| (Typ : Entity_Id; |
| Expr : Node_Id) |
| return Node_Id; |
| -- The packed array code does unchecked conversions which in some cases |
| -- may involve non-discrete types with differing sizes. The semantics of |
| -- such conversions is potentially endian dependent, and the effect we |
| -- want here for such a conversion is to do the conversion in size as |
| -- though numeric items are involved, and we extend or truncate on the |
| -- left side. This happens naturally in the little-endian case, but in |
| -- the big endian case we can get left justification, when what we want |
| -- is right justification. This routine does the unchecked conversion in |
| -- a stepwise manner to ensure that it gives the expected result. Hence |
| -- the name (RJ = Right justified). The parameters Typ and Expr are as |
| -- for the case of a normal Unchecked_Convert_To call. |
| |
| procedure Setup_Enumeration_Packed_Array_Reference (N : Node_Id); |
| -- This routine is called in the Get and Set case for arrays that are |
| -- packed but not bit-packed, meaning that they have at least one |
| -- subscript that is of an enumeration type with a non-standard |
| -- representation. This routine modifies the given node to properly |
| -- reference the corresponding packed array type. |
| |
| procedure Setup_Inline_Packed_Array_Reference |
| (N : Node_Id; |
| Atyp : Entity_Id; |
| Obj : in out Node_Id; |
| Cmask : out Uint; |
| Shift : out Node_Id); |
| -- This procedure performs common processing on the N_Indexed_Component |
| -- parameter given as N, whose prefix is a reference to a packed array. |
| -- This is used for the get and set when the component size is 1,2,4 |
| -- or for other component sizes when the packed array type is a modular |
| -- type (i.e. the cases that are handled with inline code). |
| -- |
| -- On entry: |
| -- |
| -- N is the N_Indexed_Component node for the packed array reference |
| -- |
| -- Atyp is the constrained array type (the actual subtype has been |
| -- computed if necessary to obtain the constraints, but this is still |
| -- the original array type, not the Packed_Array_Type value). |
| -- |
| -- Obj is the object which is to be indexed. It is always of type Atyp. |
| -- |
| -- On return: |
| -- |
| -- Obj is the object containing the desired bit field. It is of type |
| -- Unsigned, Long_Unsigned, or Long_Long_Unsigned, and is either the |
| -- entire value, for the small static case, or the proper selected byte |
| -- from the array in the large or dynamic case. This node is analyzed |
| -- and resolved on return. |
| -- |
| -- Shift is a node representing the shift count to be used in the |
| -- rotate right instruction that positions the field for access. |
| -- This node is analyzed and resolved on return. |
| -- |
| -- Cmask is a mask corresponding to the width of the component field. |
| -- Its value is 2 ** Csize - 1 (e.g. 2#1111# for component size of 4). |
| -- |
| -- Note: in some cases the call to this routine may generate actions |
| -- (for handling multi-use references and the generation of the packed |
| -- array type on the fly). Such actions are inserted into the tree |
| -- directly using Insert_Action. |
| |
| ------------------------------ |
| -- Compute_Linear_Subcsript -- |
| ------------------------------ |
| |
| procedure Compute_Linear_Subscript |
| (Atyp : Entity_Id; |
| N : Node_Id; |
| Subscr : out Node_Id) |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| Oldsub : Node_Id; |
| Newsub : Node_Id; |
| Indx : Node_Id; |
| Styp : Entity_Id; |
| |
| begin |
| Subscr := Empty; |
| |
| -- Loop through dimensions |
| |
| Indx := First_Index (Atyp); |
| Oldsub := First (Expressions (N)); |
| |
| while Present (Indx) loop |
| Styp := Etype (Indx); |
| Newsub := Relocate_Node (Oldsub); |
| |
| -- Get expression for the subscript value. First, if Do_Range_Check |
| -- is set on a subscript, then we must do a range check against the |
| -- original bounds (not the bounds of the packed array type). We do |
| -- this by introducing a subtype conversion. |
| |
| if Do_Range_Check (Newsub) |
| and then Etype (Newsub) /= Styp |
| then |
| Newsub := Convert_To (Styp, Newsub); |
| end if; |
| |
| -- Now evolve the expression for the subscript. First convert |
| -- the subscript to be zero based and of an integer type. |
| |
| -- Case of integer type, where we just subtract to get lower bound |
| |
| if Is_Integer_Type (Styp) then |
| |
| -- If length of integer type is smaller than standard integer, |
| -- then we convert to integer first, then do the subtract |
| |
| -- Integer (subscript) - Integer (Styp'First) |
| |
| if Esize (Styp) < Esize (Standard_Integer) then |
| Newsub := |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Convert_To (Standard_Integer, Newsub), |
| Right_Opnd => |
| Convert_To (Standard_Integer, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Styp, Loc), |
| Attribute_Name => Name_First))); |
| |
| -- For larger integer types, subtract first, then convert to |
| -- integer, this deals with strange long long integer bounds. |
| |
| -- Integer (subscript - Styp'First) |
| |
| else |
| Newsub := |
| Convert_To (Standard_Integer, |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Newsub, |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Styp, Loc), |
| Attribute_Name => Name_First))); |
| end if; |
| |
| -- For the enumeration case, we have to use 'Pos to get the value |
| -- to work with before subtracting the lower bound. |
| |
| -- Integer (Styp'Pos (subscr)) - Integer (Styp'Pos (Styp'First)); |
| |
| -- This is not quite right for bizarre cases where the size of the |
| -- enumeration type is > Integer'Size bits due to rep clause ??? |
| |
| else |
| pragma Assert (Is_Enumeration_Type (Styp)); |
| |
| Newsub := |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Convert_To (Standard_Integer, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Styp, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List (Newsub))), |
| |
| Right_Opnd => |
| Convert_To (Standard_Integer, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Styp, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Styp, Loc), |
| Attribute_Name => Name_First))))); |
| end if; |
| |
| Set_Paren_Count (Newsub, 1); |
| |
| -- For the first subscript, we just copy that subscript value |
| |
| if No (Subscr) then |
| Subscr := Newsub; |
| |
| -- Otherwise, we must multiply what we already have by the current |
| -- stride and then add in the new value to the evolving subscript. |
| |
| else |
| Subscr := |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Subscr, |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Range_Length, |
| Prefix => New_Occurrence_Of (Styp, Loc))), |
| Right_Opnd => Newsub); |
| end if; |
| |
| -- Move to next subscript |
| |
| Next_Index (Indx); |
| Next (Oldsub); |
| end loop; |
| end Compute_Linear_Subscript; |
| |
| ------------------------- |
| -- Convert_To_PAT_Type -- |
| ------------------------- |
| |
| -- The PAT is always obtained from the actual subtype |
| |
| procedure Convert_To_PAT_Type (Aexp : Entity_Id) is |
| Act_ST : Entity_Id; |
| |
| begin |
| Convert_To_Actual_Subtype (Aexp); |
| Act_ST := Underlying_Type (Etype (Aexp)); |
| Create_Packed_Array_Type (Act_ST); |
| |
| -- Just replace the etype with the packed array type. This works |
| -- because the expression will not be further analyzed, and Gigi |
| -- considers the two types equivalent in any case. |
| |
| Set_Etype (Aexp, Packed_Array_Type (Act_ST)); |
| end Convert_To_PAT_Type; |
| |
| ------------------------------ |
| -- Create_Packed_Array_Type -- |
| ------------------------------ |
| |
| procedure Create_Packed_Array_Type (Typ : Entity_Id) is |
| Loc : constant Source_Ptr := Sloc (Typ); |
| Ctyp : constant Entity_Id := Component_Type (Typ); |
| Csize : constant Uint := Component_Size (Typ); |
| |
| Ancest : Entity_Id; |
| PB_Type : Entity_Id; |
| Esiz : Uint; |
| Decl : Node_Id; |
| PAT : Entity_Id; |
| Len_Dim : Node_Id; |
| Len_Expr : Node_Id; |
| Len_Bits : Uint; |
| Bits_U1 : Node_Id; |
| PAT_High : Node_Id; |
| Btyp : Entity_Id; |
| Lit : Node_Id; |
| |
| procedure Install_PAT; |
| -- This procedure is called with Decl set to the declaration for the |
| -- packed array type. It creates the type and installs it as required. |
| |
| procedure Set_PB_Type; |
| -- Sets PB_Type to Packed_Bytes{1,2,4} as required by the alignment |
| -- requirements (see documentation in the spec of this package). |
| |
| ----------------- |
| -- Install_PAT -- |
| ----------------- |
| |
| procedure Install_PAT is |
| Pushed_Scope : Boolean := False; |
| |
| begin |
| -- We do not want to put the declaration we have created in the tree |
| -- since it is often hard, and sometimes impossible to find a proper |
| -- place for it (the impossible case arises for a packed array type |
| -- with bounds depending on the discriminant, a declaration cannot |
| -- be put inside the record, and the reference to the discriminant |
| -- cannot be outside the record). |
| |
| -- The solution is to analyze the declaration while temporarily |
| -- attached to the tree at an appropriate point, and then we install |
| -- the resulting type as an Itype in the packed array type field of |
| -- the original type, so that no explicit declaration is required. |
| |
| -- Note: the packed type is created in the scope of its parent |
| -- type. There are at least some cases where the current scope |
| -- is deeper, and so when this is the case, we temporarily reset |
| -- the scope for the definition. This is clearly safe, since the |
| -- first use of the packed array type will be the implicit |
| -- reference from the corresponding unpacked type when it is |
| -- elaborated. |
| |
| if Is_Itype (Typ) then |
| Set_Parent (Decl, Associated_Node_For_Itype (Typ)); |
| else |
| Set_Parent (Decl, Declaration_Node (Typ)); |
| end if; |
| |
| if Scope (Typ) /= Current_Scope then |
| New_Scope (Scope (Typ)); |
| Pushed_Scope := True; |
| end if; |
| |
| Set_Is_Itype (PAT, True); |
| Set_Packed_Array_Type (Typ, PAT); |
| Analyze (Decl, Suppress => All_Checks); |
| |
| if Pushed_Scope then |
| Pop_Scope; |
| end if; |
| |
| -- Set Esize and RM_Size to the actual size of the packed object |
| -- Do not reset RM_Size if already set, as happens in the case |
| -- of a modular type. |
| |
| Set_Esize (PAT, Esiz); |
| |
| if Unknown_RM_Size (PAT) then |
| Set_RM_Size (PAT, Esiz); |
| end if; |
| |
| -- Set remaining fields of packed array type |
| |
| Init_Alignment (PAT); |
| Set_Parent (PAT, Empty); |
| Set_Associated_Node_For_Itype (PAT, Typ); |
| Set_Is_Packed_Array_Type (PAT, True); |
| Set_Original_Array_Type (PAT, Typ); |
| |
| -- We definitely do not want to delay freezing for packed array |
| -- types. This is of particular importance for the itypes that |
| -- are generated for record components depending on discriminants |
| -- where there is no place to put the freeze node. |
| |
| Set_Has_Delayed_Freeze (PAT, False); |
| Set_Has_Delayed_Freeze (Etype (PAT), False); |
| end Install_PAT; |
| |
| ----------------- |
| -- Set_PB_Type -- |
| ----------------- |
| |
| procedure Set_PB_Type is |
| begin |
| -- If the user has specified an explicit alignment for the |
| -- type or component, take it into account. |
| |
| if Csize <= 2 or else Csize = 4 or else Csize mod 2 /= 0 |
| or else Alignment (Typ) = 1 |
| or else Component_Alignment (Typ) = Calign_Storage_Unit |
| then |
| PB_Type := RTE (RE_Packed_Bytes1); |
| |
| elsif Csize mod 4 /= 0 |
| or else Alignment (Typ) = 2 |
| then |
| PB_Type := RTE (RE_Packed_Bytes2); |
| |
| else |
| PB_Type := RTE (RE_Packed_Bytes4); |
| end if; |
| end Set_PB_Type; |
| |
| -- Start of processing for Create_Packed_Array_Type |
| |
| begin |
| -- If we already have a packed array type, nothing to do |
| |
| if Present (Packed_Array_Type (Typ)) then |
| return; |
| end if; |
| |
| -- If our immediate ancestor subtype is constrained, and it already |
| -- has a packed array type, then just share the same type, since the |
| -- bounds must be the same. |
| |
| if Ekind (Typ) = E_Array_Subtype then |
| Ancest := Ancestor_Subtype (Typ); |
| |
| if Present (Ancest) |
| and then Is_Constrained (Ancest) |
| and then Present (Packed_Array_Type (Ancest)) |
| then |
| Set_Packed_Array_Type (Typ, Packed_Array_Type (Ancest)); |
| return; |
| end if; |
| end if; |
| |
| -- We preset the result type size from the size of the original array |
| -- type, since this size clearly belongs to the packed array type. The |
| -- size of the conceptual unpacked type is always set to unknown. |
| |
| Esiz := Esize (Typ); |
| |
| -- Case of an array where at least one index is of an enumeration |
| -- type with a non-standard representation, but the component size |
| -- is not appropriate for bit packing. This is the case where we |
| -- have Is_Packed set (we would never be in this unit otherwise), |
| -- but Is_Bit_Packed_Array is false. |
| |
| -- Note that if the component size is appropriate for bit packing, |
| -- then the circuit for the computation of the subscript properly |
| -- deals with the non-standard enumeration type case by taking the |
| -- Pos anyway. |
| |
| if not Is_Bit_Packed_Array (Typ) then |
| |
| -- Here we build a declaration: |
| |
| -- type tttP is array (index1, index2, ...) of component_type |
| |
| -- where index1, index2, are the index types. These are the same |
| -- as the index types of the original array, except for the non- |
| -- standard representation enumeration type case, where we have |
| -- two subcases. |
| |
| -- For the unconstrained array case, we use |
| |
| -- Natural range <> |
| |
| -- For the constrained case, we use |
| |
| -- Natural range Enum_Type'Pos (Enum_Type'First) .. |
| -- Enum_Type'Pos (Enum_Type'Last); |
| |
| PAT := |
| Make_Defining_Identifier (Loc, |
| Chars => New_External_Name (Chars (Typ), 'P')); |
| |
| Set_Packed_Array_Type (Typ, PAT); |
| |
| declare |
| Indexes : constant List_Id := New_List; |
| Indx : Node_Id; |
| Indx_Typ : Entity_Id; |
| Enum_Case : Boolean; |
| Typedef : Node_Id; |
| |
| begin |
| Indx := First_Index (Typ); |
| |
| while Present (Indx) loop |
| Indx_Typ := Etype (Indx); |
| |
| Enum_Case := Is_Enumeration_Type (Indx_Typ) |
| and then Has_Non_Standard_Rep (Indx_Typ); |
| |
| -- Unconstrained case |
| |
| if not Is_Constrained (Typ) then |
| if Enum_Case then |
| Indx_Typ := Standard_Natural; |
| end if; |
| |
| Append_To (Indexes, New_Occurrence_Of (Indx_Typ, Loc)); |
| |
| -- Constrained case |
| |
| else |
| if not Enum_Case then |
| Append_To (Indexes, New_Occurrence_Of (Indx_Typ, Loc)); |
| |
| else |
| Append_To (Indexes, |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => |
| New_Occurrence_Of (Standard_Natural, Loc), |
| Constraint => |
| Make_Range_Constraint (Loc, |
| Range_Expression => |
| Make_Range (Loc, |
| Low_Bound => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Indx_Typ, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Indx_Typ, Loc), |
| Attribute_Name => Name_First))), |
| |
| High_Bound => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Indx_Typ, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List ( |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Indx_Typ, Loc), |
| Attribute_Name => Name_Last))))))); |
| |
| end if; |
| end if; |
| |
| Next_Index (Indx); |
| end loop; |
| |
| if not Is_Constrained (Typ) then |
| Typedef := |
| Make_Unconstrained_Array_Definition (Loc, |
| Subtype_Marks => Indexes, |
| Component_Definition => |
| Make_Component_Definition (Loc, |
| Aliased_Present => False, |
| Subtype_Indication => |
| New_Occurrence_Of (Ctyp, Loc))); |
| |
| else |
| Typedef := |
| Make_Constrained_Array_Definition (Loc, |
| Discrete_Subtype_Definitions => Indexes, |
| Component_Definition => |
| Make_Component_Definition (Loc, |
| Aliased_Present => False, |
| Subtype_Indication => |
| New_Occurrence_Of (Ctyp, Loc))); |
| end if; |
| |
| Decl := |
| Make_Full_Type_Declaration (Loc, |
| Defining_Identifier => PAT, |
| Type_Definition => Typedef); |
| end; |
| |
| -- Set type as packed array type and install it |
| |
| Set_Is_Packed_Array_Type (PAT); |
| Install_PAT; |
| return; |
| |
| -- Case of bit-packing required for unconstrained array. We create |
| -- a subtype that is equivalent to use Packed_Bytes{1,2,4} as needed. |
| |
| elsif not Is_Constrained (Typ) then |
| PAT := |
| Make_Defining_Identifier (Loc, |
| Chars => Make_Packed_Array_Type_Name (Typ, Csize)); |
| |
| Set_Packed_Array_Type (Typ, PAT); |
| Set_PB_Type; |
| |
| Decl := |
| Make_Subtype_Declaration (Loc, |
| Defining_Identifier => PAT, |
| Subtype_Indication => New_Occurrence_Of (PB_Type, Loc)); |
| Install_PAT; |
| return; |
| |
| -- Remaining code is for the case of bit-packing for constrained array |
| |
| -- The name of the packed array subtype is |
| |
| -- ttt___Xsss |
| |
| -- where sss is the component size in bits and ttt is the name of |
| -- the parent packed type. |
| |
| else |
| PAT := |
| Make_Defining_Identifier (Loc, |
| Chars => Make_Packed_Array_Type_Name (Typ, Csize)); |
| |
| Set_Packed_Array_Type (Typ, PAT); |
| |
| -- Build an expression for the length of the array in bits. |
| -- This is the product of the length of each of the dimensions |
| |
| declare |
| J : Nat := 1; |
| |
| begin |
| Len_Expr := Empty; -- suppress junk warning |
| |
| loop |
| Len_Dim := |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Length, |
| Prefix => New_Occurrence_Of (Typ, Loc), |
| Expressions => New_List ( |
| Make_Integer_Literal (Loc, J))); |
| |
| if J = 1 then |
| Len_Expr := Len_Dim; |
| |
| else |
| Len_Expr := |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Len_Expr, |
| Right_Opnd => Len_Dim); |
| end if; |
| |
| J := J + 1; |
| exit when J > Number_Dimensions (Typ); |
| end loop; |
| end; |
| |
| -- Temporarily attach the length expression to the tree and analyze |
| -- and resolve it, so that we can test its value. We assume that the |
| -- total length fits in type Integer. This expression may involve |
| -- discriminants, so we treat it as a default/per-object expression. |
| |
| Set_Parent (Len_Expr, Typ); |
| Analyze_Per_Use_Expression (Len_Expr, Standard_Integer); |
| |
| -- Use a modular type if possible. We can do this if we are we |
| -- have static bounds, and the length is small enough, and the |
| -- length is not zero. We exclude the zero length case because the |
| -- size of things is always at least one, and the zero length object |
| -- would have an anomous size. |
| |
| if Compile_Time_Known_Value (Len_Expr) then |
| Len_Bits := Expr_Value (Len_Expr) * Csize; |
| |
| -- We normally consider small enough to mean no larger than the |
| -- value of System_Max_Binary_Modulus_Power, checking that in the |
| -- case of values longer than word size, we have long shifts. |
| |
| if Len_Bits > 0 |
| and then |
| (Len_Bits <= System_Word_Size |
| or else (Len_Bits <= System_Max_Binary_Modulus_Power |
| and then Support_Long_Shifts_On_Target)) |
| |
| -- Also test for alignment given. If an alignment is given which |
| -- is smaller than the natural modular alignment, force the array |
| -- of bytes representation to accommodate the alignment. |
| |
| and then |
| (No (Alignment_Clause (Typ)) |
| or else |
| Alignment (Typ) >= ((Len_Bits + System_Storage_Unit) |
| / System_Storage_Unit)) |
| then |
| -- We can use the modular type, it has the form: |
| |
| -- subtype tttPn is btyp |
| -- range 0 .. 2 ** (Esize (Typ) * Csize) - 1; |
| |
| -- The bounds are statically known, and btyp is one |
| -- of the unsigned types, depending on the length. If the |
| -- type is its first subtype, i.e. it is a user-defined |
| -- type, no object of the type will be larger, and it is |
| -- worthwhile to use a small unsigned type. |
| |
| if Len_Bits <= Standard_Short_Integer_Size |
| and then First_Subtype (Typ) = Typ |
| then |
| Btyp := RTE (RE_Short_Unsigned); |
| |
| elsif Len_Bits <= Standard_Integer_Size then |
| Btyp := RTE (RE_Unsigned); |
| |
| elsif Len_Bits <= Standard_Long_Integer_Size then |
| Btyp := RTE (RE_Long_Unsigned); |
| |
| else |
| Btyp := RTE (RE_Long_Long_Unsigned); |
| end if; |
| |
| Lit := Make_Integer_Literal (Loc, 2 ** Len_Bits - 1); |
| Set_Print_In_Hex (Lit); |
| |
| Decl := |
| Make_Subtype_Declaration (Loc, |
| Defining_Identifier => PAT, |
| Subtype_Indication => |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => New_Occurrence_Of (Btyp, Loc), |
| |
| Constraint => |
| Make_Range_Constraint (Loc, |
| Range_Expression => |
| Make_Range (Loc, |
| Low_Bound => |
| Make_Integer_Literal (Loc, 0), |
| High_Bound => Lit)))); |
| |
| if Esiz = Uint_0 then |
| Esiz := Len_Bits; |
| end if; |
| |
| Install_PAT; |
| return; |
| end if; |
| end if; |
| |
| -- Could not use a modular type, for all other cases, we build |
| -- a packed array subtype: |
| |
| -- subtype tttPn is |
| -- System.Packed_Bytes{1,2,4} (0 .. (Bits + 7) / 8 - 1); |
| |
| -- Bits is the length of the array in bits. |
| |
| Set_PB_Type; |
| |
| Bits_U1 := |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Integer_Literal (Loc, Csize), |
| Right_Opnd => Len_Expr), |
| |
| Right_Opnd => |
| Make_Integer_Literal (Loc, 7)); |
| |
| Set_Paren_Count (Bits_U1, 1); |
| |
| PAT_High := |
| Make_Op_Subtract (Loc, |
| Left_Opnd => |
| Make_Op_Divide (Loc, |
| Left_Opnd => Bits_U1, |
| Right_Opnd => Make_Integer_Literal (Loc, 8)), |
| Right_Opnd => Make_Integer_Literal (Loc, 1)); |
| |
| Decl := |
| Make_Subtype_Declaration (Loc, |
| Defining_Identifier => PAT, |
| Subtype_Indication => |
| Make_Subtype_Indication (Loc, |
| Subtype_Mark => New_Occurrence_Of (PB_Type, Loc), |
| Constraint => |
| |
| Make_Index_Or_Discriminant_Constraint (Loc, |
| Constraints => New_List ( |
| Make_Range (Loc, |
| Low_Bound => |
| Make_Integer_Literal (Loc, 0), |
| High_Bound => PAT_High))))); |
| |
| Install_PAT; |
| end if; |
| end Create_Packed_Array_Type; |
| |
| ----------------------------------- |
| -- Expand_Bit_Packed_Element_Set -- |
| ----------------------------------- |
| |
| procedure Expand_Bit_Packed_Element_Set (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Lhs : constant Node_Id := Name (N); |
| |
| Ass_OK : constant Boolean := Assignment_OK (Lhs); |
| -- Used to preserve assignment OK status when assignment is rewritten |
| |
| Rhs : Node_Id := Expression (N); |
| -- Initially Rhs is the right hand side value, it will be replaced |
| -- later by an appropriate unchecked conversion for the assignment. |
| |
| Obj : Node_Id; |
| Atyp : Entity_Id; |
| PAT : Entity_Id; |
| Ctyp : Entity_Id; |
| Csiz : Int; |
| Cmask : Uint; |
| |
| Shift : Node_Id; |
| -- The expression for the shift value that is required |
| |
| Shift_Used : Boolean := False; |
| -- Set True if Shift has been used in the generated code at least |
| -- once, so that it must be duplicated if used again |
| |
| New_Lhs : Node_Id; |
| New_Rhs : Node_Id; |
| |
| Rhs_Val_Known : Boolean; |
| Rhs_Val : Uint; |
| -- If the value of the right hand side as an integer constant is |
| -- known at compile time, Rhs_Val_Known is set True, and Rhs_Val |
| -- contains the value. Otherwise Rhs_Val_Known is set False, and |
| -- the Rhs_Val is undefined. |
| |
| function Get_Shift return Node_Id; |
| -- Function used to get the value of Shift, making sure that it |
| -- gets duplicated if the function is called more than once. |
| |
| --------------- |
| -- Get_Shift -- |
| --------------- |
| |
| function Get_Shift return Node_Id is |
| begin |
| -- If we used the shift value already, then duplicate it. We |
| -- set a temporary parent in case actions have to be inserted. |
| |
| if Shift_Used then |
| Set_Parent (Shift, N); |
| return Duplicate_Subexpr_No_Checks (Shift); |
| |
| -- If first time, use Shift unchanged, and set flag for first use |
| |
| else |
| Shift_Used := True; |
| return Shift; |
| end if; |
| end Get_Shift; |
| |
| -- Start of processing for Expand_Bit_Packed_Element_Set |
| |
| begin |
| pragma Assert (Is_Bit_Packed_Array (Etype (Prefix (Lhs)))); |
| |
| Obj := Relocate_Node (Prefix (Lhs)); |
| Convert_To_Actual_Subtype (Obj); |
| Atyp := Etype (Obj); |
| PAT := Packed_Array_Type (Atyp); |
| Ctyp := Component_Type (Atyp); |
| Csiz := UI_To_Int (Component_Size (Atyp)); |
| |
| -- We convert the right hand side to the proper subtype to ensure |
| -- that an appropriate range check is made (since the normal range |
| -- check from assignment will be lost in the transformations). This |
| -- conversion is analyzed immediately so that subsequent processing |
| -- can work with an analyzed Rhs (and e.g. look at its Etype) |
| |
| Rhs := Convert_To (Ctyp, Rhs); |
| Set_Parent (Rhs, N); |
| Analyze_And_Resolve (Rhs, Ctyp); |
| |
| -- Case of component size 1,2,4 or any component size for the modular |
| -- case. These are the cases for which we can inline the code. |
| |
| if Csiz = 1 or else Csiz = 2 or else Csiz = 4 |
| or else (Present (PAT) and then Is_Modular_Integer_Type (PAT)) |
| then |
| Setup_Inline_Packed_Array_Reference (Lhs, Atyp, Obj, Cmask, Shift); |
| |
| -- The statement to be generated is: |
| |
| -- Obj := atyp!((Obj and Mask1) or (shift_left (rhs, shift))) |
| |
| -- where mask1 is obtained by shifting Cmask left Shift bits |
| -- and then complementing the result. |
| |
| -- the "and Mask1" is omitted if rhs is constant and all 1 bits |
| |
| -- the "or ..." is omitted if rhs is constant and all 0 bits |
| |
| -- rhs is converted to the appropriate type. |
| |
| -- The result is converted back to the array type, since |
| -- otherwise we lose knowledge of the packed nature. |
| |
| -- Determine if right side is all 0 bits or all 1 bits |
| |
| if Compile_Time_Known_Value (Rhs) then |
| Rhs_Val := Expr_Rep_Value (Rhs); |
| Rhs_Val_Known := True; |
| |
| -- The following test catches the case of an unchecked conversion |
| -- of an integer literal. This results from optimizing aggregates |
| -- of packed types. |
| |
| elsif Nkind (Rhs) = N_Unchecked_Type_Conversion |
| and then Compile_Time_Known_Value (Expression (Rhs)) |
| then |
| Rhs_Val := Expr_Rep_Value (Expression (Rhs)); |
| Rhs_Val_Known := True; |
| |
| else |
| Rhs_Val := No_Uint; |
| Rhs_Val_Known := False; |
| end if; |
| |
| -- Some special checks for the case where the right hand value |
| -- is known at compile time. Basically we have to take care of |
| -- the implicit conversion to the subtype of the component object. |
| |
| if Rhs_Val_Known then |
| |
| -- If we have a biased component type then we must manually do |
| -- the biasing, since we are taking responsibility in this case |
| -- for constructing the exact bit pattern to be used. |
| |
| if Has_Biased_Representation (Ctyp) then |
| Rhs_Val := Rhs_Val - Expr_Rep_Value (Type_Low_Bound (Ctyp)); |
| end if; |
| |
| -- For a negative value, we manually convert the twos complement |
| -- value to a corresponding unsigned value, so that the proper |
| -- field width is maintained. If we did not do this, we would |
| -- get too many leading sign bits later on. |
| |
| if Rhs_Val < 0 then |
| Rhs_Val := 2 ** UI_From_Int (Csiz) + Rhs_Val; |
| end if; |
| end if; |
| |
| New_Lhs := Duplicate_Subexpr (Obj, True); |
| New_Rhs := Duplicate_Subexpr_No_Checks (Obj); |
| |
| -- First we deal with the "and" |
| |
| if not Rhs_Val_Known or else Rhs_Val /= Cmask then |
| declare |
| Mask1 : Node_Id; |
| Lit : Node_Id; |
| |
| begin |
| if Compile_Time_Known_Value (Shift) then |
| Mask1 := |
| Make_Integer_Literal (Loc, |
| Modulus (Etype (Obj)) - 1 - |
| (Cmask * (2 ** Expr_Value (Get_Shift)))); |
| Set_Print_In_Hex (Mask1); |
| |
| else |
| Lit := Make_Integer_Literal (Loc, Cmask); |
| Set_Print_In_Hex (Lit); |
| Mask1 := |
| Make_Op_Not (Loc, |
| Right_Opnd => Make_Shift_Left (Lit, Get_Shift)); |
| end if; |
| |
| New_Rhs := |
| Make_Op_And (Loc, |
| Left_Opnd => New_Rhs, |
| Right_Opnd => Mask1); |
| end; |
| end if; |
| |
| -- Then deal with the "or" |
| |
| if not Rhs_Val_Known or else Rhs_Val /= 0 then |
| declare |
| Or_Rhs : Node_Id; |
| |
| procedure Fixup_Rhs; |
| -- Adjust Rhs by bias if biased representation for components |
| -- or remove extraneous high order sign bits if signed. |
| |
| procedure Fixup_Rhs is |
| Etyp : constant Entity_Id := Etype (Rhs); |
| |
| begin |
| -- For biased case, do the required biasing by simply |
| -- converting to the biased subtype (the conversion |
| -- will generate the required bias). |
| |
| if Has_Biased_Representation (Ctyp) then |
| Rhs := Convert_To (Ctyp, Rhs); |
| |
| -- For a signed integer type that is not biased, generate |
| -- a conversion to unsigned to strip high order sign bits. |
| |
| elsif Is_Signed_Integer_Type (Ctyp) then |
| Rhs := Unchecked_Convert_To (RTE (Bits_Id (Csiz)), Rhs); |
| end if; |
| |
| -- Set Etype, since it can be referenced before the |
| -- node is completely analyzed. |
| |
| Set_Etype (Rhs, Etyp); |
| |
| -- We now need to do an unchecked conversion of the |
| -- result to the target type, but it is important that |
| -- this conversion be a right justified conversion and |
| -- not a left justified conversion. |
| |
| Rhs := RJ_Unchecked_Convert_To (Etype (Obj), Rhs); |
| |
| end Fixup_Rhs; |
| |
| begin |
| if Rhs_Val_Known |
| and then Compile_Time_Known_Value (Get_Shift) |
| then |
| Or_Rhs := |
| Make_Integer_Literal (Loc, |
| Rhs_Val * (2 ** Expr_Value (Get_Shift))); |
| Set_Print_In_Hex (Or_Rhs); |
| |
| else |
| -- We have to convert the right hand side to Etype (Obj). |
| -- A special case case arises if what we have now is a Val |
| -- attribute reference whose expression type is Etype (Obj). |
| -- This happens for assignments of fields from the same |
| -- array. In this case we get the required right hand side |
| -- by simply removing the inner attribute reference. |
| |
| if Nkind (Rhs) = N_Attribute_Reference |
| and then Attribute_Name (Rhs) = Name_Val |
| and then Etype (First (Expressions (Rhs))) = Etype (Obj) |
| then |
| Rhs := Relocate_Node (First (Expressions (Rhs))); |
| Fixup_Rhs; |
| |
| -- If the value of the right hand side is a known integer |
| -- value, then just replace it by an untyped constant, |
| -- which will be properly retyped when we analyze and |
| -- resolve the expression. |
| |
| elsif Rhs_Val_Known then |
| |
| -- Note that Rhs_Val has already been normalized to |
| -- be an unsigned value with the proper number of bits. |
| |
| Rhs := |
| Make_Integer_Literal (Loc, Rhs_Val); |
| |
| -- Otherwise we need an unchecked conversion |
| |
| else |
| Fixup_Rhs; |
| end if; |
| |
| Or_Rhs := Make_Shift_Left (Rhs, Get_Shift); |
| end if; |
| |
| if Nkind (New_Rhs) = N_Op_And then |
| Set_Paren_Count (New_Rhs, 1); |
| end if; |
| |
| New_Rhs := |
| Make_Op_Or (Loc, |
| Left_Opnd => New_Rhs, |
| Right_Opnd => Or_Rhs); |
| end; |
| end if; |
| |
| -- Now do the rewrite |
| |
| Rewrite (N, |
| Make_Assignment_Statement (Loc, |
| Name => New_Lhs, |
| Expression => |
| Unchecked_Convert_To (Etype (New_Lhs), New_Rhs))); |
| Set_Assignment_OK (Name (N), Ass_OK); |
| |
| -- All other component sizes for non-modular case |
| |
| else |
| -- We generate |
| |
| -- Set_nn (Arr'address, Subscr, Bits_nn!(Rhs)) |
| |
| -- where Subscr is the computed linear subscript. |
| |
| declare |
| Bits_nn : constant Entity_Id := RTE (Bits_Id (Csiz)); |
| Set_nn : Entity_Id; |
| Subscr : Node_Id; |
| Atyp : Entity_Id; |
| |
| begin |
| if No (Bits_nn) then |
| |
| -- Error, most likely High_Integrity_Mode restriction. |
| |
| return; |
| end if; |
| |
| -- Acquire proper Set entity. We use the aligned or unaligned |
| -- case as appropriate. |
| |
| if Known_Aligned_Enough (Obj, Csiz) then |
| Set_nn := RTE (Set_Id (Csiz)); |
| else |
| Set_nn := RTE (SetU_Id (Csiz)); |
| end if; |
| |
| -- Now generate the set reference |
| |
| Obj := Relocate_Node (Prefix (Lhs)); |
| Convert_To_Actual_Subtype (Obj); |
| Atyp := Etype (Obj); |
| Compute_Linear_Subscript (Atyp, Lhs, Subscr); |
| |
| -- Below we must make the assumption that Obj is |
| -- at least byte aligned, since otherwise its address |
| -- cannot be taken. The assumption holds since the |
| -- only arrays that can be misaligned are small packed |
| -- arrays which are implemented as a modular type, and |
| -- that is not the case here. |
| |
| Rewrite (N, |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (Set_nn, Loc), |
| Parameter_Associations => New_List ( |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => Obj), |
| Subscr, |
| Unchecked_Convert_To (Bits_nn, |
| Convert_To (Ctyp, Rhs))))); |
| |
| end; |
| end if; |
| |
| Analyze (N, Suppress => All_Checks); |
| end Expand_Bit_Packed_Element_Set; |
| |
| ------------------------------------- |
| -- Expand_Packed_Address_Reference -- |
| ------------------------------------- |
| |
| procedure Expand_Packed_Address_Reference (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Ploc : Source_Ptr; |
| Pref : Node_Id; |
| Expr : Node_Id; |
| Term : Node_Id; |
| Atyp : Entity_Id; |
| Subscr : Node_Id; |
| |
| begin |
| Pref := Prefix (N); |
| Expr := Empty; |
| |
| -- We build up an expression serially that has the form |
| |
| -- outer_object'Address |
| -- + (linear-subscript * component_size for each array reference |
| -- + field'Bit_Position for each record field |
| -- + ... |
| -- + ...) / Storage_Unit; |
| |
| -- Some additional conversions are required to deal with the addition |
| -- operation, which is not normally visible to generated code. |
| |
| loop |
| Ploc := Sloc (Pref); |
| |
| if Nkind (Pref) = N_Indexed_Component then |
| Convert_To_Actual_Subtype (Prefix (Pref)); |
| Atyp := Etype (Prefix (Pref)); |
| Compute_Linear_Subscript (Atyp, Pref, Subscr); |
| |
| Term := |
| Make_Op_Multiply (Ploc, |
| Left_Opnd => Subscr, |
| Right_Opnd => |
| Make_Attribute_Reference (Ploc, |
| Prefix => New_Occurrence_Of (Atyp, Ploc), |
| Attribute_Name => Name_Component_Size)); |
| |
| elsif Nkind (Pref) = N_Selected_Component then |
| Term := |
| Make_Attribute_Reference (Ploc, |
| Prefix => Selector_Name (Pref), |
| Attribute_Name => Name_Bit_Position); |
| |
| else |
| exit; |
| end if; |
| |
| Term := Convert_To (RTE (RE_Integer_Address), Term); |
| |
| if No (Expr) then |
| Expr := Term; |
| |
| else |
| Expr := |
| Make_Op_Add (Ploc, |
| Left_Opnd => Expr, |
| Right_Opnd => Term); |
| end if; |
| |
| Pref := Prefix (Pref); |
| end loop; |
| |
| Rewrite (N, |
| Unchecked_Convert_To (RTE (RE_Address), |
| Make_Op_Add (Loc, |
| Left_Opnd => |
| Unchecked_Convert_To (RTE (RE_Integer_Address), |
| Make_Attribute_Reference (Loc, |
| Prefix => Pref, |
| Attribute_Name => Name_Address)), |
| |
| Right_Opnd => |
| Make_Op_Divide (Loc, |
| Left_Opnd => Expr, |
| Right_Opnd => |
| Make_Integer_Literal (Loc, System_Storage_Unit))))); |
| |
| Analyze_And_Resolve (N, RTE (RE_Address)); |
| end Expand_Packed_Address_Reference; |
| |
| ------------------------------------ |
| -- Expand_Packed_Boolean_Operator -- |
| ------------------------------------ |
| |
| -- This routine expands "a op b" for the packed cases |
| |
| procedure Expand_Packed_Boolean_Operator (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| L : constant Node_Id := Relocate_Node (Left_Opnd (N)); |
| R : constant Node_Id := Relocate_Node (Right_Opnd (N)); |
| |
| Ltyp : Entity_Id; |
| Rtyp : Entity_Id; |
| PAT : Entity_Id; |
| |
| begin |
| Convert_To_Actual_Subtype (L); |
| Convert_To_Actual_Subtype (R); |
| |
| Ensure_Defined (Etype (L), N); |
| Ensure_Defined (Etype (R), N); |
| |
| Apply_Length_Check (R, Etype (L)); |
| |
| Ltyp := Etype (L); |
| Rtyp := Etype (R); |
| |
| -- First an odd and silly test. We explicitly check for the XOR |
| -- case where the component type is True .. True, since this will |
| -- raise constraint error. A special check is required since CE |
| -- will not be required other wise (cf Expand_Packed_Not). |
| |
| -- No such check is required for AND and OR, since for both these |
| -- cases False op False = False, and True op True = True. |
| |
| if Nkind (N) = N_Op_Xor then |
| declare |
| CT : constant Entity_Id := Component_Type (Rtyp); |
| BT : constant Entity_Id := Base_Type (CT); |
| |
| begin |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_And (Loc, |
| Left_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (CT, Loc), |
| Attribute_Name => Name_First), |
| |
| Right_Opnd => |
| Convert_To (BT, |
| New_Occurrence_Of (Standard_True, Loc))), |
| |
| Right_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (CT, Loc), |
| Attribute_Name => Name_Last), |
| |
| Right_Opnd => |
| Convert_To (BT, |
| New_Occurrence_Of (Standard_True, Loc)))), |
| Reason => CE_Range_Check_Failed)); |
| end; |
| end if; |
| |
| -- Now that that silliness is taken care of, get packed array type |
| |
| Convert_To_PAT_Type (L); |
| Convert_To_PAT_Type (R); |
| |
| PAT := Etype (L); |
| |
| -- For the modular case, we expand a op b into |
| |
| -- rtyp!(pat!(a) op pat!(b)) |
| |
| -- where rtyp is the Etype of the left operand. Note that we do not |
| -- convert to the base type, since this would be unconstrained, and |
| -- hence not have a corresponding packed array type set. |
| |
| -- Note that both operands must be modular for this code to be used. |
| |
| if Is_Modular_Integer_Type (PAT) |
| and then |
| Is_Modular_Integer_Type (Etype (R)) |
| then |
| declare |
| P : Node_Id; |
| |
| begin |
| if Nkind (N) = N_Op_And then |
| P := Make_Op_And (Loc, L, R); |
| |
| elsif Nkind (N) = N_Op_Or then |
| P := Make_Op_Or (Loc, L, R); |
| |
| else -- Nkind (N) = N_Op_Xor |
| P := Make_Op_Xor (Loc, L, R); |
| end if; |
| |
| Rewrite (N, Unchecked_Convert_To (Rtyp, P)); |
| end; |
| |
| -- For the array case, we insert the actions |
| |
| -- Result : Ltype; |
| |
| -- System.Bitops.Bit_And/Or/Xor |
| -- (Left'Address, |
| -- Ltype'Length * Ltype'Component_Size; |
| -- Right'Address, |
| -- Rtype'Length * Rtype'Component_Size |
| -- Result'Address); |
| |
| -- where Left and Right are the Packed_Bytes{1,2,4} operands and |
| -- the second argument and fourth arguments are the lengths of the |
| -- operands in bits. Then we replace the expression by a reference |
| -- to Result. |
| |
| -- Note that if we are mixing a modular and array operand, everything |
| -- works fine, since we ensure that the modular representation has the |
| -- same physical layout as the array representation (that's what the |
| -- left justified modular stuff in the big-endian case is about). |
| |
| else |
| declare |
| Result_Ent : constant Entity_Id := |
| Make_Defining_Identifier (Loc, |
| Chars => New_Internal_Name ('T')); |
| |
| E_Id : RE_Id; |
| |
| begin |
| if Nkind (N) = N_Op_And then |
| E_Id := RE_Bit_And; |
| |
| elsif Nkind (N) = N_Op_Or then |
| E_Id := RE_Bit_Or; |
| |
| else -- Nkind (N) = N_Op_Xor |
| E_Id := RE_Bit_Xor; |
| end if; |
| |
| Insert_Actions (N, New_List ( |
| |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Result_Ent, |
| Object_Definition => New_Occurrence_Of (Ltyp, Loc)), |
| |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (RTE (E_Id), Loc), |
| Parameter_Associations => New_List ( |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => L), |
| |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of |
| (Etype (First_Index (Ltyp)), Loc), |
| Attribute_Name => Name_Range_Length), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Component_Size (Ltyp))), |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => R), |
| |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of |
| (Etype (First_Index (Rtyp)), Loc), |
| Attribute_Name => Name_Range_Length), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Component_Size (Rtyp))), |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => New_Occurrence_Of (Result_Ent, Loc)))))); |
| |
| Rewrite (N, |
| New_Occurrence_Of (Result_Ent, Loc)); |
| end; |
| end if; |
| |
| Analyze_And_Resolve (N, Typ, Suppress => All_Checks); |
| end Expand_Packed_Boolean_Operator; |
| |
| ------------------------------------- |
| -- Expand_Packed_Element_Reference -- |
| ------------------------------------- |
| |
| procedure Expand_Packed_Element_Reference (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Obj : Node_Id; |
| Atyp : Entity_Id; |
| PAT : Entity_Id; |
| Ctyp : Entity_Id; |
| Csiz : Int; |
| Shift : Node_Id; |
| Cmask : Uint; |
| Lit : Node_Id; |
| Arg : Node_Id; |
| |
| begin |
| -- If not bit packed, we have the enumeration case, which is easily |
| -- dealt with (just adjust the subscripts of the indexed component) |
| |
| -- Note: this leaves the result as an indexed component, which is |
| -- still a variable, so can be used in the assignment case, as is |
| -- required in the enumeration case. |
| |
| if not Is_Bit_Packed_Array (Etype (Prefix (N))) then |
| Setup_Enumeration_Packed_Array_Reference (N); |
| return; |
| end if; |
| |
| -- Remaining processing is for the bit-packed case. |
| |
| Obj := Relocate_Node (Prefix (N)); |
| Convert_To_Actual_Subtype (Obj); |
| Atyp := Etype (Obj); |
| PAT := Packed_Array_Type (Atyp); |
| Ctyp := Component_Type (Atyp); |
| Csiz := UI_To_Int (Component_Size (Atyp)); |
| |
| -- Case of component size 1,2,4 or any component size for the modular |
| -- case. These are the cases for which we can inline the code. |
| |
| if Csiz = 1 or else Csiz = 2 or else Csiz = 4 |
| or else (Present (PAT) and then Is_Modular_Integer_Type (PAT)) |
| then |
| Setup_Inline_Packed_Array_Reference (N, Atyp, Obj, Cmask, Shift); |
| Lit := Make_Integer_Literal (Loc, Cmask); |
| Set_Print_In_Hex (Lit); |
| |
| -- We generate a shift right to position the field, followed by a |
| -- masking operation to extract the bit field, and we finally do an |
| -- unchecked conversion to convert the result to the required target. |
| |
| -- Note that the unchecked conversion automatically deals with the |
| -- bias if we are dealing with a biased representation. What will |
| -- happen is that we temporarily generate the biased representation, |
| -- but almost immediately that will be converted to the original |
| -- unbiased component type, and the bias will disappear. |
| |
| Arg := |
| Make_Op_And (Loc, |
| Left_Opnd => Make_Shift_Right (Obj, Shift), |
| Right_Opnd => Lit); |
| |
| -- We neded to analyze this before we do the unchecked convert |
| -- below, but we need it temporarily attached to the tree for |
| -- this analysis (hence the temporary Set_Parent call). |
| |
| Set_Parent (Arg, Parent (N)); |
| Analyze_And_Resolve (Arg); |
| |
| Rewrite (N, |
| RJ_Unchecked_Convert_To (Ctyp, Arg)); |
| |
| -- All other component sizes for non-modular case |
| |
| else |
| -- We generate |
| |
| -- Component_Type!(Get_nn (Arr'address, Subscr)) |
| |
| -- where Subscr is the computed linear subscript. |
| |
| declare |
| Get_nn : Entity_Id; |
| Subscr : Node_Id; |
| |
| begin |
| -- Acquire proper Get entity. We use the aligned or unaligned |
| -- case as appropriate. |
| |
| if Known_Aligned_Enough (Obj, Csiz) then |
| Get_nn := RTE (Get_Id (Csiz)); |
| else |
| Get_nn := RTE (GetU_Id (Csiz)); |
| end if; |
| |
| -- Now generate the get reference |
| |
| Compute_Linear_Subscript (Atyp, N, Subscr); |
| |
| -- Below we make the assumption that Obj is at least byte |
| -- aligned, since otherwise its address cannot be taken. |
| -- The assumption holds since the only arrays that can be |
| -- misaligned are small packed arrays which are implemented |
| -- as a modular type, and that is not the case here. |
| |
| Rewrite (N, |
| Unchecked_Convert_To (Ctyp, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (Get_nn, Loc), |
| Parameter_Associations => New_List ( |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => Obj), |
| Subscr)))); |
| end; |
| end if; |
| |
| Analyze_And_Resolve (N, Ctyp, Suppress => All_Checks); |
| |
| end Expand_Packed_Element_Reference; |
| |
| ---------------------- |
| -- Expand_Packed_Eq -- |
| ---------------------- |
| |
| -- Handles expansion of "=" on packed array types |
| |
| procedure Expand_Packed_Eq (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| L : constant Node_Id := Relocate_Node (Left_Opnd (N)); |
| R : constant Node_Id := Relocate_Node (Right_Opnd (N)); |
| |
| LLexpr : Node_Id; |
| RLexpr : Node_Id; |
| |
| Ltyp : Entity_Id; |
| Rtyp : Entity_Id; |
| PAT : Entity_Id; |
| |
| begin |
| Convert_To_Actual_Subtype (L); |
| Convert_To_Actual_Subtype (R); |
| Ltyp := Underlying_Type (Etype (L)); |
| Rtyp := Underlying_Type (Etype (R)); |
| |
| Convert_To_PAT_Type (L); |
| Convert_To_PAT_Type (R); |
| PAT := Etype (L); |
| |
| LLexpr := |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Length, |
| Prefix => New_Occurrence_Of (Ltyp, Loc)), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Component_Size (Ltyp))); |
| |
| RLexpr := |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Attribute_Name => Name_Length, |
| Prefix => New_Occurrence_Of (Rtyp, Loc)), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Component_Size (Rtyp))); |
| |
| -- For the modular case, we transform the comparison to: |
| |
| -- Ltyp'Length = Rtyp'Length and then PAT!(L) = PAT!(R) |
| |
| -- where PAT is the packed array type. This works fine, since in the |
| -- modular case we guarantee that the unused bits are always zeroes. |
| -- We do have to compare the lengths because we could be comparing |
| -- two different subtypes of the same base type. |
| |
| if Is_Modular_Integer_Type (PAT) then |
| Rewrite (N, |
| Make_And_Then (Loc, |
| Left_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => LLexpr, |
| Right_Opnd => RLexpr), |
| |
| Right_Opnd => |
| Make_Op_Eq (Loc, |
| Left_Opnd => L, |
| Right_Opnd => R))); |
| |
| -- For the non-modular case, we call a runtime routine |
| |
| -- System.Bit_Ops.Bit_Eq |
| -- (L'Address, L_Length, R'Address, R_Length) |
| |
| -- where PAT is the packed array type, and the lengths are the lengths |
| -- in bits of the original packed arrays. This routine takes care of |
| -- not comparing the unused bits in the last byte. |
| |
| else |
| Rewrite (N, |
| Make_Function_Call (Loc, |
| Name => New_Occurrence_Of (RTE (RE_Bit_Eq), Loc), |
| Parameter_Associations => New_List ( |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => L), |
| |
| LLexpr, |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => R), |
| |
| RLexpr))); |
| end if; |
| |
| Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); |
| end Expand_Packed_Eq; |
| |
| ----------------------- |
| -- Expand_Packed_Not -- |
| ----------------------- |
| |
| -- Handles expansion of "not" on packed array types |
| |
| procedure Expand_Packed_Not (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Typ : constant Entity_Id := Etype (N); |
| Opnd : constant Node_Id := Relocate_Node (Right_Opnd (N)); |
| |
| Rtyp : Entity_Id; |
| PAT : Entity_Id; |
| Lit : Node_Id; |
| |
| begin |
| Convert_To_Actual_Subtype (Opnd); |
| Rtyp := Etype (Opnd); |
| |
| -- First an odd and silly test. We explicitly check for the case |
| -- where the 'First of the component type is equal to the 'Last of |
| -- this component type, and if this is the case, we make sure that |
| -- constraint error is raised. The reason is that the NOT is bound |
| -- to cause CE in this case, and we will not otherwise catch it. |
| |
| -- Believe it or not, this was reported as a bug. Note that nearly |
| -- always, the test will evaluate statically to False, so the code |
| -- will be statically removed, and no extra overhead caused. |
| |
| declare |
| CT : constant Entity_Id := Component_Type (Rtyp); |
| |
| begin |
| Insert_Action (N, |
| Make_Raise_Constraint_Error (Loc, |
| Condition => |
| Make_Op_Eq (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (CT, Loc), |
| Attribute_Name => Name_First), |
| |
| Right_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (CT, Loc), |
| Attribute_Name => Name_Last)), |
| Reason => CE_Range_Check_Failed)); |
| end; |
| |
| -- Now that that silliness is taken care of, get packed array type |
| |
| Convert_To_PAT_Type (Opnd); |
| PAT := Etype (Opnd); |
| |
| -- For the case where the packed array type is a modular type, |
| -- not A expands simply into: |
| |
| -- rtyp!(PAT!(A) xor mask) |
| |
| -- where PAT is the packed array type, and mask is a mask of all |
| -- one bits of length equal to the size of this packed type and |
| -- rtyp is the actual subtype of the operand |
| |
| Lit := Make_Integer_Literal (Loc, 2 ** Esize (PAT) - 1); |
| Set_Print_In_Hex (Lit); |
| |
| if not Is_Array_Type (PAT) then |
| Rewrite (N, |
| Unchecked_Convert_To (Rtyp, |
| Make_Op_Xor (Loc, |
| Left_Opnd => Opnd, |
| Right_Opnd => Lit))); |
| |
| -- For the array case, we insert the actions |
| |
| -- Result : Typ; |
| |
| -- System.Bitops.Bit_Not |
| -- (Opnd'Address, |
| -- Typ'Length * Typ'Component_Size; |
| -- Result'Address); |
| |
| -- where Opnd is the Packed_Bytes{1,2,4} operand and the second |
| -- argument is the length of the operand in bits. Then we replace |
| -- the expression by a reference to Result. |
| |
| else |
| declare |
| Result_Ent : constant Entity_Id := |
| Make_Defining_Identifier (Loc, |
| Chars => New_Internal_Name ('T')); |
| |
| begin |
| Insert_Actions (N, New_List ( |
| |
| Make_Object_Declaration (Loc, |
| Defining_Identifier => Result_Ent, |
| Object_Definition => New_Occurrence_Of (Rtyp, Loc)), |
| |
| Make_Procedure_Call_Statement (Loc, |
| Name => New_Occurrence_Of (RTE (RE_Bit_Not), Loc), |
| Parameter_Associations => New_List ( |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => Opnd), |
| |
| Make_Op_Multiply (Loc, |
| Left_Opnd => |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of |
| (Etype (First_Index (Rtyp)), Loc), |
| Attribute_Name => Name_Range_Length), |
| Right_Opnd => |
| Make_Integer_Literal (Loc, Component_Size (Rtyp))), |
| |
| Make_Byte_Aligned_Attribute_Reference (Loc, |
| Attribute_Name => Name_Address, |
| Prefix => New_Occurrence_Of (Result_Ent, Loc)))))); |
| |
| Rewrite (N, |
| New_Occurrence_Of (Result_Ent, Loc)); |
| end; |
| end if; |
| |
| Analyze_And_Resolve (N, Typ, Suppress => All_Checks); |
| |
| end Expand_Packed_Not; |
| |
| ------------------------------------- |
| -- Involves_Packed_Array_Reference -- |
| ------------------------------------- |
| |
| function Involves_Packed_Array_Reference (N : Node_Id) return Boolean is |
| begin |
| if Nkind (N) = N_Indexed_Component |
| and then Is_Bit_Packed_Array (Etype (Prefix (N))) |
| then |
| return True; |
| |
| elsif Nkind (N) = N_Selected_Component then |
| return Involves_Packed_Array_Reference (Prefix (N)); |
| |
| else |
| return False; |
| end if; |
| end Involves_Packed_Array_Reference; |
| |
| -------------------------- |
| -- Known_Aligned_Enough -- |
| -------------------------- |
| |
| function Known_Aligned_Enough (Obj : Node_Id; Csiz : Nat) return Boolean is |
| Typ : constant Entity_Id := Etype (Obj); |
| |
| function In_Partially_Packed_Record (Comp : Entity_Id) return Boolean; |
| -- If the component is in a record that contains previous packed |
| -- components, consider it unaligned because the back-end might |
| -- choose to pack the rest of the record. Lead to less efficient code, |
| -- but safer vis-a-vis of back-end choices. |
| |
| -------------------------------- |
| -- In_Partially_Packed_Record -- |
| -------------------------------- |
| |
| function In_Partially_Packed_Record (Comp : Entity_Id) return Boolean is |
| Rec_Type : constant Entity_Id := Scope (Comp); |
| Prev_Comp : Entity_Id; |
| |
| begin |
| Prev_Comp := First_Entity (Rec_Type); |
| while Present (Prev_Comp) loop |
| if Is_Packed (Etype (Prev_Comp)) then |
| return True; |
| |
| elsif Prev_Comp = Comp then |
| return False; |
| end if; |
| |
| Next_Entity (Prev_Comp); |
| end loop; |
| |
| return False; |
| end In_Partially_Packed_Record; |
| |
| -- Start of processing for Known_Aligned_Enough |
| |
| begin |
| -- Odd bit sizes don't need alignment anyway |
| |
| if Csiz mod 2 = 1 then |
| return True; |
| |
| -- If we have a specified alignment, see if it is sufficient, if not |
| -- then we can't possibly be aligned enough in any case. |
| |
| elsif Known_Alignment (Etype (Obj)) then |
| -- Alignment required is 4 if size is a multiple of 4, and |
| -- 2 otherwise (e.g. 12 bits requires 4, 10 bits requires 2) |
| |
| if Alignment (Etype (Obj)) < 4 - (Csiz mod 4) then |
| return False; |
| end if; |
| end if; |
| |
| -- OK, alignment should be sufficient, if object is aligned |
| |
| -- If object is strictly aligned, then it is definitely aligned |
| |
| if Strict_Alignment (Typ) then |
| return True; |
| |
| -- Case of subscripted array reference |
| |
| elsif Nkind (Obj) = N_Indexed_Component then |
| |
| -- If we have a pointer to an array, then this is definitely |
| -- aligned, because pointers always point to aligned versions. |
| |
| if Is_Access_Type (Etype (Prefix (Obj))) then |
| return True; |
| |
| -- Otherwise, go look at the prefix |
| |
| else |
| return Known_Aligned_Enough (Prefix (Obj), Csiz); |
| end if; |
| |
| -- Case of record field |
| |
| elsif Nkind (Obj) = N_Selected_Component then |
| |
| -- What is significant here is whether the record type is packed |
| |
| if Is_Record_Type (Etype (Prefix (Obj))) |
| and then Is_Packed (Etype (Prefix (Obj))) |
| then |
| return False; |
| |
| -- Or the component has a component clause which might cause |
| -- the component to become unaligned (we can't tell if the |
| -- backend is doing alignment computations). |
| |
| elsif Present (Component_Clause (Entity (Selector_Name (Obj)))) then |
| return False; |
| |
| elsif In_Partially_Packed_Record (Entity (Selector_Name (Obj))) then |
| return False; |
| |
| -- In all other cases, go look at prefix |
| |
| else |
| return Known_Aligned_Enough (Prefix (Obj), Csiz); |
| end if; |
| |
| elsif Nkind (Obj) = N_Type_Conversion then |
| return Known_Aligned_Enough (Expression (Obj), Csiz); |
| |
| -- For a formal parameter, it is safer to assume that it is not |
| -- aligned, because the formal may be unconstrained while the actual |
| -- is constrained. In this situation, a small constrained packed |
| -- array, represented in modular form, may be unaligned. |
| |
| elsif Is_Entity_Name (Obj) then |
| return not Is_Formal (Entity (Obj)); |
| else |
| |
| -- If none of the above, must be aligned |
| return True; |
| end if; |
| end Known_Aligned_Enough; |
| |
| --------------------- |
| -- Make_Shift_Left -- |
| --------------------- |
| |
| function Make_Shift_Left (N : Node_Id; S : Node_Id) return Node_Id is |
| Nod : Node_Id; |
| |
| begin |
| if Compile_Time_Known_Value (S) and then Expr_Value (S) = 0 then |
| return N; |
| else |
| Nod := |
| Make_Op_Shift_Left (Sloc (N), |
| Left_Opnd => N, |
| Right_Opnd => S); |
| Set_Shift_Count_OK (Nod, True); |
| return Nod; |
| end if; |
| end Make_Shift_Left; |
| |
| ---------------------- |
| -- Make_Shift_Right -- |
| ---------------------- |
| |
| function Make_Shift_Right (N : Node_Id; S : Node_Id) return Node_Id is |
| Nod : Node_Id; |
| |
| begin |
| if Compile_Time_Known_Value (S) and then Expr_Value (S) = 0 then |
| return N; |
| else |
| Nod := |
| Make_Op_Shift_Right (Sloc (N), |
| Left_Opnd => N, |
| Right_Opnd => S); |
| Set_Shift_Count_OK (Nod, True); |
| return Nod; |
| end if; |
| end Make_Shift_Right; |
| |
| ----------------------------- |
| -- RJ_Unchecked_Convert_To -- |
| ----------------------------- |
| |
| function RJ_Unchecked_Convert_To |
| (Typ : Entity_Id; |
| Expr : Node_Id) |
| return Node_Id |
| is |
| Source_Typ : constant Entity_Id := Etype (Expr); |
| Target_Typ : constant Entity_Id := Typ; |
| |
| Src : Node_Id := Expr; |
| |
| Source_Siz : Nat; |
| Target_Siz : Nat; |
| |
| begin |
| Source_Siz := UI_To_Int (RM_Size (Source_Typ)); |
| Target_Siz := UI_To_Int (RM_Size (Target_Typ)); |
| |
| -- First step, if the source type is not a discrete type, then we |
| -- first convert to a modular type of the source length, since |
| -- otherwise, on a big-endian machine, we get left-justification. |
| -- We do it for little-endian machines as well, because there might |
| -- be junk bits that are not cleared if the type is not numeric. |
| |
| if Source_Siz /= Target_Siz |
| and then not Is_Discrete_Type (Source_Typ) |
| then |
| Src := Unchecked_Convert_To (RTE (Bits_Id (Source_Siz)), Src); |
| end if; |
| |
| -- In the big endian case, if the lengths of the two types differ, |
| -- then we must worry about possible left justification in the |
| -- conversion, and avoiding that is what this is all about. |
| |
| if Bytes_Big_Endian and then Source_Siz /= Target_Siz then |
| |
| -- Next step. If the target is not a discrete type, then we first |
| -- convert to a modular type of the target length, since |
| -- otherwise, on a big-endian machine, we get left-justification. |
| |
| if not Is_Discrete_Type (Target_Typ) then |
| Src := Unchecked_Convert_To (RTE (Bits_Id (Target_Siz)), Src); |
| end if; |
| end if; |
| |
| -- And now we can do the final conversion to the target type |
| |
| return Unchecked_Convert_To (Target_Typ, Src); |
| end RJ_Unchecked_Convert_To; |
| |
| ---------------------------------------------- |
| -- Setup_Enumeration_Packed_Array_Reference -- |
| ---------------------------------------------- |
| |
| -- All we have to do here is to find the subscripts that correspond |
| -- to the index positions that have non-standard enumeration types |
| -- and insert a Pos attribute to get the proper subscript value. |
| |
| -- Finally the prefix must be uncheck converted to the corresponding |
| -- packed array type. |
| |
| -- Note that the component type is unchanged, so we do not need to |
| -- fiddle with the types (Gigi always automatically takes the packed |
| -- array type if it is set, as it will be in this case). |
| |
| procedure Setup_Enumeration_Packed_Array_Reference (N : Node_Id) is |
| Pfx : constant Node_Id := Prefix (N); |
| Typ : constant Entity_Id := Etype (N); |
| Exprs : constant List_Id := Expressions (N); |
| Expr : Node_Id; |
| |
| begin |
| -- If the array is unconstrained, then we replace the array |
| -- reference with its actual subtype. This actual subtype will |
| -- have a packed array type with appropriate bounds. |
| |
| if not Is_Constrained (Packed_Array_Type (Etype (Pfx))) then |
| Convert_To_Actual_Subtype (Pfx); |
| end if; |
| |
| Expr := First (Exprs); |
| while Present (Expr) loop |
| declare |
| Loc : constant Source_Ptr := Sloc (Expr); |
| Expr_Typ : constant Entity_Id := Etype (Expr); |
| |
| begin |
| if Is_Enumeration_Type (Expr_Typ) |
| and then Has_Non_Standard_Rep (Expr_Typ) |
| then |
| Rewrite (Expr, |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Expr_Typ, Loc), |
| Attribute_Name => Name_Pos, |
| Expressions => New_List (Relocate_Node (Expr)))); |
| Analyze_And_Resolve (Expr, Standard_Natural); |
| end if; |
| end; |
| |
| Next (Expr); |
| end loop; |
| |
| Rewrite (N, |
| Make_Indexed_Component (Sloc (N), |
| Prefix => |
| Unchecked_Convert_To (Packed_Array_Type (Etype (Pfx)), Pfx), |
| Expressions => Exprs)); |
| |
| Analyze_And_Resolve (N, Typ); |
| |
| end Setup_Enumeration_Packed_Array_Reference; |
| |
| ----------------------------------------- |
| -- Setup_Inline_Packed_Array_Reference -- |
| ----------------------------------------- |
| |
| procedure Setup_Inline_Packed_Array_Reference |
| (N : Node_Id; |
| Atyp : Entity_Id; |
| Obj : in out Node_Id; |
| Cmask : out Uint; |
| Shift : out Node_Id) |
| is |
| Loc : constant Source_Ptr := Sloc (N); |
| PAT : Entity_Id; |
| Otyp : Entity_Id; |
| Csiz : Uint; |
| Osiz : Uint; |
| |
| begin |
| Csiz := Component_Size (Atyp); |
| |
| Convert_To_PAT_Type (Obj); |
| PAT := Etype (Obj); |
| |
| Cmask := 2 ** Csiz - 1; |
| |
| if Is_Array_Type (PAT) then |
| Otyp := Component_Type (PAT); |
| Osiz := Component_Size (PAT); |
| |
| else |
| Otyp := PAT; |
| |
| -- In the case where the PAT is a modular type, we want the actual |
| -- size in bits of the modular value we use. This is neither the |
| -- Object_Size nor the Value_Size, either of which may have been |
| -- reset to strange values, but rather the minimum size. Note that |
| -- since this is a modular type with full range, the issue of |
| -- biased representation does not arise. |
| |
| Osiz := UI_From_Int (Minimum_Size (Otyp)); |
| end if; |
| |
| Compute_Linear_Subscript (Atyp, N, Shift); |
| |
| -- If the component size is not 1, then the subscript must be |
| -- multiplied by the component size to get the shift count. |
| |
| if Csiz /= 1 then |
| Shift := |
| Make_Op_Multiply (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Csiz), |
| Right_Opnd => Shift); |
| end if; |
| |
| -- If we have the array case, then this shift count must be broken |
| -- down into a byte subscript, and a shift within the byte. |
| |
| if Is_Array_Type (PAT) then |
| |
| declare |
| New_Shift : Node_Id; |
| |
| begin |
| -- We must analyze shift, since we will duplicate it |
| |
| Set_Parent (Shift, N); |
| Analyze_And_Resolve |
| (Shift, Standard_Integer, Suppress => All_Checks); |
| |
| -- The shift count within the word is |
| -- shift mod Osiz |
| |
| New_Shift := |
| Make_Op_Mod (Loc, |
| Left_Opnd => Duplicate_Subexpr (Shift), |
| Right_Opnd => Make_Integer_Literal (Loc, Osiz)); |
| |
| -- The subscript to be used on the PAT array is |
| -- shift / Osiz |
| |
| Obj := |
| Make_Indexed_Component (Loc, |
| Prefix => Obj, |
| Expressions => New_List ( |
| Make_Op_Divide (Loc, |
| Left_Opnd => Duplicate_Subexpr (Shift), |
| Right_Opnd => Make_Integer_Literal (Loc, Osiz)))); |
| |
| Shift := New_Shift; |
| end; |
| |
| -- For the modular integer case, the object to be manipulated is |
| -- the entire array, so Obj is unchanged. Note that we will reset |
| -- its type to PAT before returning to the caller. |
| |
| else |
| null; |
| end if; |
| |
| -- The one remaining step is to modify the shift count for the |
| -- big-endian case. Consider the following example in a byte: |
| |
| -- xxxxxxxx bits of byte |
| -- vvvvvvvv bits of value |
| -- 33221100 little-endian numbering |
| -- 00112233 big-endian numbering |
| |
| -- Here we have the case of 2-bit fields |
| |
| -- For the little-endian case, we already have the proper shift |
| -- count set, e.g. for element 2, the shift count is 2*2 = 4. |
| |
| -- For the big endian case, we have to adjust the shift count, |
| -- computing it as (N - F) - shift, where N is the number of bits |
| -- in an element of the array used to implement the packed array, |
| -- F is the number of bits in a source level array element, and |
| -- shift is the count so far computed. |
| |
| if Bytes_Big_Endian then |
| Shift := |
| Make_Op_Subtract (Loc, |
| Left_Opnd => Make_Integer_Literal (Loc, Osiz - Csiz), |
| Right_Opnd => Shift); |
| end if; |
| |
| Set_Parent (Shift, N); |
| Set_Parent (Obj, N); |
| Analyze_And_Resolve (Obj, Otyp, Suppress => All_Checks); |
| Analyze_And_Resolve (Shift, Standard_Integer, Suppress => All_Checks); |
| |
| -- Make sure final type of object is the appropriate packed type |
| |
| Set_Etype (Obj, Otyp); |
| |
| end Setup_Inline_Packed_Array_Reference; |
| |
| end Exp_Pakd; |
