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-- --
-- --
-- S E T _ T A R G --
-- --
-- S p e c --
-- --
-- Copyright (C) 2013-2021, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
-- This package handles setting target dependent parameters. If the -gnatet
-- switch is not set, then these values are taken from the back end (via the
-- routines in Get_Targ, and the enumerate_modes routine in misc.c). If the
-- switch is set, then the values are read from the target.atp file in the
-- current directory (usually written with the Write_Target_Dependent_Values
-- procedure defined in this package).
-- Note that all these values return sizes of C types with corresponding
-- names. This allows GNAT to define the corresponding Ada types to have
-- the same representation. There is one exception: the representation
-- of Wide_Character_Type uses twice the size of a C char, instead of the
-- size of wchar_t, since this corresponds to expected Ada usage.
with Stand; use Stand;
with Types; use Types;
package Set_Targ is
-- Target-Dependent Values --
-- The following is a table of target dependent values. In normal operation
-- these values are set by calling the appropriate C backend routines that
-- interface to back end routines that determine target characteristics.
-- If the -gnateT switch is used, then any values that are read from the
-- file target.atp in the current directory overwrite values set from the
-- back end. This is used by tools other than the compiler, e.g. to do
-- semantic analysis of programs that will run on some other target than
-- the machine on which the tool is run.
-- Note: fields marked with a question mark are boolean fields, where a
-- value of 0 is False, and a value of 1 is True.
Bits_BE : Nat; -- Bits stored big-endian?
Bits_Per_Unit : Pos; -- Bits in a storage unit
Bits_Per_Word : Pos; -- Bits in a word
Bytes_BE : Nat; -- Bytes stored big-endian?
Char_Size : Pos; -- Standard.Character'Size
Double_Float_Alignment : Nat; -- Alignment of double float
Double_Scalar_Alignment : Nat; -- Alignment of double length scalar
Double_Size : Pos; -- Standard.Long_Float'Size
Float_Size : Pos; -- Standard.Float'Size
Float_Words_BE : Nat; -- Float words stored big-endian?
Int_Size : Pos; -- Standard.Integer'Size
Long_Double_Size : Pos; -- Standard.Long_Long_Float'Size
Long_Long_Long_Size : Pos; -- Standard.Long_Long_Long_Integer'Size
Long_Long_Size : Pos; -- Standard.Long_Long_Integer'Size
Long_Size : Pos; -- Standard.Long_Integer'Size
Maximum_Alignment : Pos; -- Maximum permitted alignment
Max_Unaligned_Field : Pos; -- Maximum size for unaligned bit field
Pointer_Size : Pos; -- System.Address'Size
Short_Enums : Nat; -- Foreign enums use short size?
Short_Size : Pos; -- Standard.Short_Integer'Size
Strict_Alignment : Nat; -- Strict alignment?
System_Allocator_Alignment : Nat; -- Alignment for malloc calls
Wchar_T_Size : Pos; -- Interfaces.C.wchar_t'Size
Words_BE : Nat; -- Words stored big-endian?
-- Registered Floating-Point Types --
-- This table contains the list of modes supported by the back-end as
-- provided by the back end routine enumerate_modes in misc.c. Note that
-- we only store floating-point modes (see Register_Float_Type).
type FPT_Mode_Entry is record
NAME : String_Ptr; -- Name of mode (no null character at end)
DIGS : Natural; -- Digits for floating-point type
FLOAT_REP : Float_Rep_Kind; -- Float representation
PRECISION : Natural; -- Precision in bits
SIZE : Natural; -- Size in bits
ALIGNMENT : Natural; -- Alignment in bits
end record;
FPT_Mode_Table : array (1 .. 1000) of FPT_Mode_Entry;
Num_FPT_Modes : Natural := 0;
-- Table containing the supported modes and number of entries
-- Subprograms --
subtype S_Float_Types is
Standard_Entity_Type range S_Short_Float .. S_Long_Long_Float;
function C_Type_For (T : S_Float_Types) return String;
-- Return the name of a C type supported by the back-end and suitable as
-- a basis to construct the standard Ada floating point type identified by
-- T. This is used as a common ground to feed both ttypes values and the
-- GNAT tree nodes for the standard floating point types.
procedure Write_Target_Dependent_Values;
-- This routine writes the file target.atp in the current directory with
-- the values of the global target parameters as listed above, and as set
-- by prior calls to Initialize/Read_Target_Dependent_Values. The format
-- of the target.atp file is as follows
-- First come the values of the variables defined in this spec:
-- One line per value
-- name value
-- where name is the name of the parameter, spelled out in full,
-- and cased as in the above list, and value is an unsigned decimal
-- integer. Two or more blanks separates the name from the value.
-- All the variables must be present, in alphabetical order (i.e. the
-- same order as the declarations in this spec).
-- Then there is a blank line to separate the two parts of the file. Then
-- come the lines showing the floating-point types to be registered.
-- One line per registered mode
-- name digs float_rep precision alignment
-- where name is the string name of the type (which can have
-- single spaces embedded in the name (e.g. long double). The
-- name is followed by at least two blanks. The following fields
-- are as described above for a Mode_Entry (where float_rep is
-- I for IEEE-754-Binary, which is the only Float_Rep_Kind
-- currently supported), fields are separated by at least one
-- blank, and a LF character immediately follows the alignment
-- field.
-- ??? We do not write the size for backward compatibility reasons,
-- which means that target.atp will not be a complete description for
-- the very peculiar cases where the size cannot be computed from the
-- precision and the alignment by the formula:
-- size := (precision + alignment - 1) / alignment * alignment
end Set_Targ;