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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- L I B . W R I T --
-- --
-- S p e c --
-- --
-- $Revision$
-- --
-- Copyright (C) 1992-2001 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. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This package contains the routines for writing the library information
package Lib.Writ is
-----------------------------------
-- Format of Library Information --
-----------------------------------
-- Note: the contents of the ali file are summarized in the GNAT
-- user's guide, so if any non-trivial changes are made to this
-- section, they should be reflected in the user's guide.
-- This section describes the format of the library information that is
-- associated with object files. The exact method of this association is
-- potentially implementation dependent and is described and implemented
-- in package From the point of view of the description here, all we
-- need to know is that the information is represented as a string of
-- characters that is somehow associated with an object file, and can be
-- retrieved. If no library information exists for a given object file,
-- then we take this as equivalent to the non-existence of the object
-- file, as if source file has not been previously compiled.
-- The library information is written as a series of lines of the form:
-- Key_Character parameter parameter ...
------------------
-- Header Lines --
------------------
-- The initial header lines in the file give information about the
-- compilation environment, and identify other special information
-- such as main program parameters.
-- ----------------
-- -- V Version --
-- ----------------
-- V "xxxxxxxxxxxxxxxx"
--
-- This line indicates the library output version, as defined in
-- Gnatvsn. It ensures that separate object modules of a program are
-- consistent. It has to be changed if anything changes which would
-- affect successful binding of separately compiled modules.
-- Examples of such changes are modifications in the format of the
-- library info described in this package, or modifications to
-- calling sequences, or to the way that data is represented.
-- ---------------------
-- -- M Main Program --
-- ---------------------
-- M type [priority] [T=time-slice] W=?
-- This line appears only if the main unit for this file is
-- suitable for use as a main program. The parameters are:
-- type
-- P for a parameterless procedure
-- F for a function returning a value of integral type
-- (used for writing a main program returning an exit status)
-- priority
-- Present only if there was a valid pragma Priority in the
-- corresponding unit to set the main task priority. It is
-- an unsigned decimal integer.
-- T=time-slice
-- Present only if there was a valid pragma Time_Slice in the
-- corresponding unit. It is an unsigned decimal integer in
-- the range 0 .. 10**9 giving the time slice value in units
-- of milliseconds. The actual significance of this parameter
-- is target dependent.
-- W=?
-- This parameter indicates the wide character encoding
-- method used when compiling the main program file. The ?
-- character is the single character used in the -gnatW?
-- switch. This is used to provide the default wide-character
-- encoding for Wide_Text_IO files.
-- -----------------
-- -- A Argument --
-- -----------------
-- A argument
-- One of these lines appears for each of the arguments present
-- in the call to the gnat1 program. This can be used if it is
-- necessary to reconstruct this call (e.g. for fix and continue)
-- -------------------
-- -- P Parameters --
-- -------------------
-- P <<parameters>>
-- Indicates various information that applies to the compilation
-- of the corresponding source unit. Parameters is a sequence of
-- zero or more two letter codes that indicate configuration
-- pragmas and other parameters that apply:
--
-- Present if the unit uses tasking directly or indirectly and
-- has one or more valid xxx_Policy pragmas that apply to the unit.
-- The arguments are as follows:
--
-- CE Compilation errors. If this is present it means that the
-- ali file resulted from a compilation with the -gnatQ
-- switch set, and illegalities were detected. The ali
-- file contents may not be completely reliable, but the
-- format will be correct and complete. Note that NO is
-- always present if CE is present.
--
-- FD Configuration pragmas apply to all the units in this
-- file specifying a possibly non-standard floating point
-- format (VAX float with Long_Float using D_Float)
--
-- FG Configuration pragmas apply to all the units in this
-- file specifying a possibly non-standard floating point
-- format (VAX float with Long_Float using G_Float)
--
-- FI Configuration pragmas apply to all the units in this
-- file specifying a possibly non-standard floating point
-- format (IEEE Float)
--
-- Lx A valid Locking_Policy pragma applies to all the units
-- in this file, where x is the first character (upper case)
-- of the policy name (e.g. 'C' for Ceiling_Locking)
--
-- NO No object. This flag indicates that the units in this
-- file were not compiled to produce an object. This can
-- occur as a result of the use of -gnatc, or if no object
-- can be produced (e.g. when a package spec is compiled
-- instead of the body, or a subunit on its own).
--
-- NR No_Run_Time pragma in effect for all units in this file
--
-- NS Normalize_Scalars pragma in effect for all units in
-- this file
--
-- Qx A valid Queueing_Policy pragma applies to all the units
-- in this file, where x is the first character (upper case)
-- of the policy name (e.g. 'P' for Priority_Queueing).
--
-- Tx A valid Task_Dispatching_Policy pragma applies to all
-- the units in this file, where x is the first character
-- (upper case) of the corresponding policy name (e.g. 'F'
-- for FIFO_Within_Priorities).
--
-- UA Unreserve_All_Interrupts pragma was processed in one or
-- more units in this file
--
-- UX Generated code contains unit exception table pointer
-- (i.e. it uses zero-cost exceptions, and there is at
-- least one subprogram present).
--
-- ZX Units in this file use zero-cost exceptions and have
-- generated exception tables. If ZX is not present, the
-- longjmp/setjmp exception scheme is in use.
--
-- Note that language defined units never output policy (Lx,Tx,Qx)
-- parameters. Language defined units must correctly handle all
-- possible cases. These values are checked for consistency by the
-- binder and then copied to the generated binder output file.
-- ---------------------
-- -- R Restrictions --
-- ---------------------
-- R <<restriction-characters>>
-- This line records information regarding restrictions. The
-- parameter is a string of characters, one for each entry in
-- Restrict.Partition_Restrictions, in order. There are three
-- settings possible settings for each restriction:
-- r Restricted. Unit was compiled under control of a pragma
-- Restrictions for the corresponding restriction. In
-- this case the unit certainly does not violate the
-- Restriction, since this would have been detected by
-- the compiler.
-- n Not used. The unit was not compiled under control of a
-- pragma Restrictions for the corresponding restriction,
-- and does not make any use of the referenced feature.
-- v Violated. The unit was not compiled uner control of a
-- pragma Restrictions for the corresponding restriction,
-- and it does indeed use the referenced feature.
-- This information is used in the binder to check consistency,
-- i.e. to detect cases where one unit has "r" and another unit
-- has "v", which is not permitted, since these restrictions
-- are partition-wide.
----------------------------
-- Compilation Unit Lines --
----------------------------
-- Following these header lines, a set of information lines appears for
-- each compilation unit that appears in the corresponding object file.
-- In particular, when a package body or subprogram body is compiled,
-- there will be two sets of information, one for the spec and one for
-- the body. with the entry for the body appearing first. This is the
-- only case in which a single ALI file contains more than one unit (in
-- particular note that subunits do *not* count as compilation units for
-- this purpose, and generate no library information, since they are
-- inlined).
-- --------------------
-- -- U Unit Header --
-- --------------------
-- The lines for each compilation unit have the following form.
-- U unit-name source-name version <<attributes>>
--
-- This line identifies the unit to which this section of the
-- library information file applies. The first three parameters are
-- the unit name in internal format, as described in package Uname,
-- and the name of the source file containing the unit.
--
-- Version is the version given as eight hexadecimal characters
-- with upper case letters. This value is the exclusive or of the
-- source checksums of the unit and all its semantically dependent
-- units.
--
-- The <<attributes>> are a series of two letter codes indicating
-- information about the unit:
--
-- DE Dynamic Elaboration. This unit was compiled with the
-- dynamic elaboration model, as set by either the -gnatE
-- switch or pragma Elaboration_Checks (Dynamic).
--
-- EB Unit has pragma Elaborate_Body
--
-- EE Elaboration entity is present which must be set true when
-- the unit is elaborated. The name of the elaboration entity
-- is formed from the unit name in the usual way. If EE is
-- present, then this boolean must be set True as part of the
-- elaboration processing routine generated by the binder.
-- Note that EE can be set even if NE is set. This happens
-- when the boolean is needed solely for checking for the
-- case of access before elaboration.
--
-- GE Unit is a generic declaration, or corresponding body
--
-- IL Unit source uses a style with identifiers in all lower
-- IU case (IL) or all upper case (IU). If the standard mixed-
-- case usage is detected, or the compiler cannot determine
-- the style, then no I parameter will appear.
--
-- IS Initialize_Scalars pragma applies to this unit
--
-- KM Unit source uses a style with keywords in mixed case
-- KU (KM) or all upper case (KU). If the standard lower-case
-- usage is detected, or the compiler cannot determine the
-- style, then no K parameter will appear.
--
-- NE Unit has no elaboration routine. All subprogram bodies
-- and specs are in this category. Package bodies and specs
-- may or may not have NE set, depending on whether or not
-- elaboration code is required. Set if N_Compilation_Unit
-- node has flag Has_No_Elaboration_Code set.
--
-- PK Unit is package, rather than a subprogram
--
-- PU Unit has pragma Pure
--
-- PR Unit has pragma Preelaborate
--
-- RA Unit declares a Remote Access to Class-Wide (RACW) type
--
-- RC Unit has pragma Remote_Call_Interface
--
-- RT Unit has pragma Remote_Types
--
-- SP Unit has pragma Shared_Passive.
--
-- SU Unit is a subprogram, rather than a package
--
-- The attributes may appear in any order, separated by spaces.
-- ---------------------
-- -- W Withed Units --
-- ---------------------
-- Following each U line, is a series of lines of the form
-- W unit-name [source-name lib-name] [E] [EA] [ED]
--
-- One of these lines is present for each unit that is mentioned in
-- an explicit with clause by the current unit. The first parameter
-- is the unit name in internal format. The second parameter is the
-- file name of the file that must be compiled to compile this unit
-- (which is usually the file for the body, except for packages
-- which have no body). The third parameter is the file name of the
-- library information file that contains the results of compiling
-- this unit. The optional modifiers are used as follows:
--
-- E pragma Elaborate applies to this unit
--
-- EA pragma Elaborate_All applies to this unit
--
-- ED Elaborate_All_Desirable set for this unit, which means
-- that there is no Elaborate_All, but the analysis suggests
-- that Program_Error may be raised if the Elaborate_All
-- conditions cannot be satisfied. The binder will attempt
-- to treat ED as EA if it can.
--
-- The parameter source-name and lib-name are omitted for the case
-- of a generic unit compiled with earlier versions of GNAT which
-- did not generate object or ali files for generics.
---------------------
-- Reference Lines --
---------------------
-- The reference lines contain information about references from
-- any of the units in the compilation (including, body version
-- and version attributes, linker options pragmas and source
-- dependencies.
-- -----------------------
-- -- L Linker_Options --
-- -----------------------
-- Following the unit information is an optional series of lines that
-- indicates the usage of pragma Linker_Options. For each appearence
-- of pragma Linker_Actions in any of the units for which unit lines
-- are present, a line of the form:
-- L "string"
-- where string is the string from the unit line enclosed in quotes.
-- Within the quotes the following can occur:
-- c graphic characters in range 20-7E other than " or {
-- "" indicating a single " character
-- {hh} indicating a character whose code is hex hh (0-9,A-F)
-- {00} [ASCII.NUL] is used as a separator character
-- to separate multiple arguments of a single
-- Linker_Options pragma.
-- For further details, see Stringt.Write_String_Table_Entry. Note
-- that wide characters in the form {hhhh} cannot be produced, since
-- pragma Linker_Option accepts only String, not Wide_String.
-- ------------------------------------
-- -- E External Version References --
-- ------------------------------------
-- One of these lines is present for each use of 'Body_Version or
-- 'Version in any of the units of the compilation. These are used
-- by the linker to determine which version symbols must be output.
-- The format is simply:
-- E name
-- where name is the external name, i.e. the unit name with either
-- a S or a B for spec or body version referenced (Body_Version
-- always references the body, Version references the Spec, except
-- in the case of a reference to a subprogram with no separate spec).
-- Upper half and wide character codes are encoded using the same
-- method as in Namet (Uhh for upper half, Whhhh for wide character,
-- where hh are hex digits).
-- ---------------------
-- -- D Dependencies --
-- ---------------------
-- The dependency lines indicate the source files on which the compiled
-- units depend. This is used by the binder for consistency checking.
-- These lines are also referenced by the cross-reference information.
-- D source-name time-stamp checksum [subunit-name] line:file-name
-- The time-stamp field contains the time stamp of the
-- corresponding source file. See types.ads for details on
-- time stamp representation.
-- The checksum is an 8-hex digit representation of the source
-- file checksum, with letters given in lower case.
-- The subunit name is present only if the dependency line is for
-- a subunit. It contains the fully qualified name of the subunit
-- in all lower case letters.
-- The line:file-name entry is present only if a Source_Reference
-- pragma appeared in the source file identified by source-name.
-- In this case, it gives the information from this pragma. Note
-- that this allows cross-reference information to be related back
-- to the original file. Note: the reason the line number comes
-- first is that a leading digit immediately identifies this as
-- a Source_Reference entry, rather than a subunit-name.
-- A line number of zero for line: in this entry indicates that
-- there is more than one source reference pragma. In this case,
-- the line numbers in the cross-reference are correct, and refer
-- to the original line number, but there is no information that
-- allows a reader of the ALI file to determine the exact mapping
-- of physical line numbers back to the original source.
-- Note: blank lines are ignored when the library information is
-- read, and separate sections of the file are separated by blank
-- lines to ease readability. Blanks between fields are also
-- ignored.
-- For entries corresponding to files that were not present (and
-- thus resulted in error messages), or for files that are not
-- part of the dependency set, both the time stamp and checksum
-- are set to all zero characters. These dummy entries are ignored
-- by the binder in dependency checking, but must be present for
-- proper interpretation of the cross-reference data.
--------------------------
-- Cross-Reference Data --
--------------------------
-- The cross-reference data follows the dependency lines. See
-- the spec of Lib.Xref for details on the format of this data.
-----------------
-- Subprograms --
-----------------
procedure Ensure_System_Dependency;
-- This procedure ensures that a dependency is created on system.ads.
-- Even if there is no semantic dependency, Targparm has read the
-- file to acquire target parameters, so we need a source dependency.
procedure Write_ALI (Object : Boolean);
-- This procedure writes the library information for the current main unit
-- The Object parameter is true if an object file is created, and false
-- otherwise.
--
-- Note: in the case where we are not generating code (-gnatc mode), this
-- routine only writes an ALI file if it cannot find an existing up to
-- date ALI file. If it *can* find an existing up to date ALI file, then
-- it reads this file and sets the Lib.Compilation_Arguments table from
-- the A lines in this file.
end Lib.Writ;